<PAGE>

                                 UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                   Form 10-Q

(Mark One)
(X)     QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
        EXCHANGE ACT OF 1934

        For the quarterly period ended June 30, 1996

                                      OR

(  )    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
        EXCHANGE ACT OF 1934

        For the transition period from __________ to __________

        Commission File Number 0-19034

                        REGENERON PHARMACEUTICALS, INC.
            (Exact name of registrant as specified in its charter)

       New York                                       13-3444607
(State or other jurisdiction of           (I.R.S. Employer Identification No.)
incorporation or organization)

                 777 Old Saw Mill River Road
                     Tarrytown, New York                     10591-6707
          (Address of principal executive offices)           (Zip code)

                                (914) 347-7000
             (Registrant's telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                Yes  X      No ___


Indicate the number of shares outstanding of each of the issuer's classes of
common stock as of August 2, 1996:

           Class of Common Stock                     Number of Shares
      Class A Stock, $0.001 par value                    4,767,004
      Common Stock, $0.001 par value                    20,835,586


                                 Page 1 of 145




<PAGE>


                        REGENERON PHARMACEUTICALS, INC.
                               Table of Contents
                                 June 30, 1996

                                                                   Page Numbers


PART I -        FINANCIAL INFORMATION


Item 1. Financial Statements

             Condensed balance sheets (unaudited) at June 30, 1996
             and December 31, 1995                                       3
        
             Condensed statements of operations (unaudited) for the 
             three months and six months ended June 30, 1996 and 1995    4
        
             Condensed statements of cash flows (unaudited) for the
             six months ended June 30, 1996 and 1995                     5
        
             Notes to condensed financial statements                     6-8
        

Item 2.      Management's Discussion and Analysis of
             Financial Condition and Results of Operations               9-16


PART II-     OTHER INFORMATION


Item 4.      Submission of Matters to a Vote of Security Holders         17


Item 6.      Exhibits and Reports on Form 8-K                            18

SIGNATURE PAGE                                                           19

Exhibit 10.1    Stock and Warrant Purchase Agreement dated as of 
                April 15, 1996, between the Company and Amgen Inc.       20-36

Exhibit 10.2    Warrant Agreement dated as of April 15, 1996, between 
                the Company and Amgen Inc.                               37-62

Exhibit 10.3    Registration Rights Agreement dated as of April 15, 
                1996, between the Company and Amgen Inc.                 63-86

Exhibit 10.4    Stock and Warrant Purchase Agreement dated as of 
                June 27, 1996, between the Company and Medtronic, Inc.   87-103

Exhibit 10.5    Warrant Agreement dated as of June 27, 1996, between 
                the Company and Medtronic, Inc.                          104-126

Exhibit 10.6    Registration Rights Agreement dated as of June 27, 
                1996, between the Company and Medtronic, Inc.            127-141


Exhibit 10.7    Assignment and Assumption Agreement dated as of 
                June 27, 1996, between the Company and Medtronic, Inc.   142-143

Exhibit 11      Statement of computation of loss per share for the three
                months and six months ended June 30, 1996 and 1995       144

Exhibit 27      Financial data schedule                                  145


                                       2




<PAGE>


PART 1.  FINANCIAL INFORMATION

ITEM 1.   FINANCIAL STATEMENTS

REGENERON PHARMACEUTICALS, INC. 
CONDENSED BALANCE SHEETS AT JUNE 30, 1996 AND DECEMBER 31, 1995 (Unaudited)

                                                   June 30,       December 31,
                     ASSETS                          1996             1995
                                                     ----             ----  
Current assets
    Cash and cash equivalents                     $48,850,085      $32,736,026 
    Marketable securities                          26,088,654       13,417,634 
    Receivable due from Amgen-Regeneron Partners      985,542          668,990 
    Receivable due from Sumitomo Pharmaceuticals 
      Company, Ltd.                                 2,352,483        1,749,062 
    Receivable due from Merck & Co., Inc.           3,066,164          271,630 
    Prepaid expenses and other current assets         334,700          359,111 
                                                 ------------     ------------ 
       Total current assets                        81,677,628       49,202,453 

Marketable securities                              21,393,852       13,468,350 
Investment in Amgen-Regeneron Partners              1,615,458        1,273,538 
Property, plant and equipment, at cost, net of 
  accumulated depreciation and amortization  of 
  $16,777,650 in 1996 and $14,402,833 in 1995      33,336,670       27,870,720 
Other assets                                        1,248,582        1,996,284
                                                 ------------     ------------ 
       Total assets                              $139,272,190      $93,811,345 
                                                 ============     ============
LIABILITIES and STOCKHOLDERS' EQUITY
Current liabilities
    Accounts payable and accrued expenses          $4,247,055       $6,289,832 
    Note payable, current portion                      80,481           83,444 
    Capital lease obligations, current portion      3,603,976        3,408,090 
    Deferred revenue, current portion               1,670,830        3,166,665
                                                 ------------     ------------ 
       Total current liabilities                    9,602,342       12,948,031 

Capital lease obligations                           3,071,425        4,152,100 
Note payable                                        1,787,298        1,825,766 
Other liabilities                                     143,845          103,374 

Deferred revenue                                   11,866,632        6,925,625 

Commitments and contingencies

Stockholders' equity
    Preferred stock, $.01 par value; 30,000,000 
      shares authorized; issued and outstanding 
      - none
    Class A Stock, convertible, $.001 par value; 
      40,000,000 shares authorized;

        4,817,815 shares issued (4,800,742 
        outstanding) in 1996; 5,403,923 shares 
        issued (5,386,850 outstanding) in 1995          4,818            5,404 
    Common Stock, $.001 par value; 60,000,000 
      shares authorized; 20,795,448 shares 
      issued and outstanding in 1996; 
      16,465,429 shares issued and outstanding 
      in 1995                                          20,796           16,465 
    Additional paid-in capital                    254,058,076      193,594,141 
    Unearned compensation                          (1,260,000)      (1,440,000)
    Accumulated deficit                          (139,997,465)    (124,605,334)
    Net unrealized (loss) gain on marketable 
      securities                                      (25,410)         285,940 
                                                 ------------     ------------
                                                  112,800,815       67,856,616 
    Less, Class A Stock held in treasury, 
      at cost: 17,073 shares in 1996 and 1995            (167)            (167)
                                                 ------------     ------------
       Total stockholders' equity                 112,800,648       67,856,449 
                                                 ------------     ------------
       Total liabilities and stockholders' 
         equity                                  $139,272,190      $93,811,345 
                                                 ============     ============

   The accompanying notes are an integral part of the financial statements.


                                       3




<PAGE>

REGENERON PHARMACEUTICALS, INC.
CONDENSED STATEMENTS OF OPERATIONS (Unaudited)


<TABLE>
<CAPTION>
                                              Three months                  Six months    
                                             ended June 30,                ended June 30,    
                                          1996           1995           1996           1995    
                                          ----           ----           ----           ----
<S>                                   <C>            <C>           <C>              <C>
Revenues
  Contract research and development    $4,596,390     $6,807,634     $8,779,286     $13,706,349  
  Contract manufacturing                  431,009                       836,360  
  Investment income                     1,130,763        815,642      1,731,185       1,749,805    
                                      -----------    -----------   ------------     -----------  
                                        6,158,162      7,623,276     11,346,831      15,456,154      
                                      -----------    -----------   ------------     -----------  

Expenses
  Research and development              6,802,561      5,750,606     13,728,964      11,640,759   
  Loss in Amgen-Regeneron Partners      3,517,180      2,849,895      6,179,080       5,409,700  
  General and administrative            1,586,554      1,552,734      3,097,499       3,228,116  
  Depreciation and amortization         1,525,301      1,472,069      3,016,255       2,978,108    
  Interest                                227,429        378,871        478,058         750,771     
  Other                                   123,770                       239,106    
                                      -----------    -----------   ------------     -----------  
                                       13,782,795     12,004,175     26,738,962      24,007,454    
                                      -----------    -----------   ------------     -----------  
Net loss                              ($7,624,633)   ($4,380,899)  ($15,392,131)    ($8,551,300)  
                                      ===========    ===========   ============     ===========  
Net loss per share                         ($0.31)        ($0.22)        ($0.66)         ($0.44)   
                                      ===========    ===========   ============     ===========  
Weighted average number of Common
   and Class A shares outstanding      24,585,518     19,487,627     23,296,691      19,406,248  
                                      ===========    ===========   ============     ===========  

</TABLE>


   The accompanying notes are an integral part of the financial statements.

                                4




<PAGE>

REGENERON PHARMACEUTICALS, INC. 
CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) 
Increase (Decrease) in Cash and Cash Equivalents


                                                     Six  months ended June 30,
                                                        1996          1995
                                                        ----          ----
Cash flows from operating activities
  Net loss                                          ($15,392,131)  ($8,551,300)
                                                    ------------   -----------
  Adjustments to reconcile net loss to net cash
    used in operating activities
      Loss in Amgen-Regeneron Partners                 6,179,080     5,409,700 
      Depreciation and amortization                    3,016,255     2,978,108 
      Amortization of lease incentive                                  (50,300)
      Stock issued in consideration for services 
        rendered                                         180,000       180,000 
      Changes in assets and liabilities
        (Increase) decrease in amounts due from 
          Amgen-Regeneron Partners                      (316,552)      332,685 
        Increase in amounts due from Sumitomo 
          Pharmaceuticals Co., Ltd.                     (603,421)   (1,749,047)
        Increase in amounts due from Merck & Co., 
          Inc.                                        (2,794,534)
        Increase in investment in Amgen-Regeneron 
          Partners                                    (6,521,000)
        Decrease (increase) in prepaid expenses
          and other assets                               130,675      (402,599)
        Increase (decrease) in deferred revenue        3,445,172    (6,416,667)
        Decrease in accounts payable, accrued 
          expenses, and other liabilities               (533,047)     (778,476)
                                                    ------------   -----------
            Total adjustments                          2,182,628      (496,596)
                                                    ------------   -----------
          Net cash used in operating activities      (13,209,503)   (9,047,896)
                                                    ------------   -----------

Cash flows from investing activities
  Purchases of marketable securities                 (41,117,516)  (21,660,071)
  Sales of marketable securities                      20,209,644    25,223,126 
  Capital expenditures                                (7,462,280)     (161,206)
                                                    ------------   -----------

          Net cash (used in) provided by 
            investing activities                     (28,370,152)    3,401,849 
                                                    ------------   -----------

Cash flows from financing activities
  Net proceeds from the issuance of stock             59,394,527       363,044 
  Principal payments on note payable                     (41,431)      (45,282)

  Capital lease payments                              (1,659,382)   (1,478,238)
  Purchase of treasury stock                                                (5)
                                                    ------------   -----------

          Net cash provided by (used in) 
            financing activities                      57,693,714    (1,160,481)
                                                    ------------   -----------

          Net increase (decrease) in cash 
            and cash equivalents                      16,114,059    (6,806,528)
                                                    ------------   -----------

Cash and cash equivalents at beginning 
  of period                                           32,736,026    23,645,914 
                                                    ------------   -----------

          Cash and cash equivalents at end of 
            period                                   $48,850,085   $16,839,386 
                                                    ============   ===========

Supplemental disclosure of cash flow information
          Cash paid for interest                        $437,586      $698,485 
                                                    ============   ===========


   The accompanying notes are an integral part of the financial statements.

                                       5




<PAGE>


REGENERON PHARMACEUTICALS, INC.

Notes to Condensed Financial Statements


1.      Interim Financial Statements

        In the opinion of management of the Company, the accompanying unaudited
interim financial statements reflect all adjustments, consisting only of normal
recurring accruals, necessary to present fairly the Company's financial
position as of June 30, 1996 and December 31, 1995 and the results of
operations for the three and six months ended June 30, 1996 and 1995. The
results of operations for such interim periods are not necessarily indicative
of the results to be expected for the full year. The condensed interim
financial statements should be read in conjunction with the audited financial
statements included in the Company's annual report on Form 10-K.

        Certain reclassifications have been made to the financial statements
for 1995 in order to conform with the current period's presentation.


2.      Statement of Cash Flows

        Supplemental disclosure of noncash investing and financing activities:

        Capital lease obligations of approximately $775,000 and $132,000 were
incurred during the first six months of 1996 and 1995, respectively, when the
Company leased new equipment.

        Included in accounts payable and accrued expenses at June 30, 1996 were
approximately $688,000 of capital expenditures and approximately $115,000 of
costs incurred in connection with the Company's issuance of equity securities.

        At December 31, 1995, the Company had accrued $850,000 as its
contribution to the settlement of a securities class action lawsuit. During
January 1996, the Company issued shares of its Common Stock, valued at
$850,000, in settlement of this obligation.


3.      Accounts Payable and Accrued Expenses

        Accounts payable and accrued expenses as of June 30, 1996 and December
31, 1995 consist of the following:

                                                   June 30,       December 31,
                                                     1996            1995
                                                     ----            ----
     Accounts payable                            $2,062,690       $3,240,050
     Accrued payroll and related costs            1,028,887        1,054,626
     Accrued clinical trial expense                 319,500          350,000 
     Accrued litigation settlement                                   850,000

     Accrued expenses, other                        407,543          299,412
     Deferred compensation                          428,435          495,744
                                                 ----------       ---------- 
                                                 $4,247,055       $6,289,832
                                                 ==========       ==========

                                       6


<PAGE>

4.      Marketable Securities

        The following table summarizes the amortized cost basis of marketable
securities, the aggregate fair value of marketable securities, and gross
unrealized holding gains and losses at June 30, 1996:


<TABLE>
<CAPTION>

                                                                                   Unrealized Holding
                                          Amortized         Fair          ---------------------------------------
                                          Cost Basis        Value          Gains         (Losses)          Net
                                          ----------        -----          -----         --------          --- 
<S>                                       <C>             <C>             <C>            <C>             <C>
Maturities within one year
  Corporate debt securities               $22,109,392     $22,155,252     $ 50,991        ($ 5,131)       $45,860
  U.S. Government securities                3,897,592       3,933,402       35,810              --         35,810
                                          -----------     -----------     --------       ---------       --------
                                           26,006,984      26,088,654       86,801          (5,131)        81,670
                                          -----------     -----------     --------       ---------       --------
Maturities between one and two years
  Corporate debt securities                 6,235,286       6,244,632       11,601          (2,255)         9,346
  U.S. Government securities               15,265,646      15,149,220        3,637        (120,063)      (116,426)
                                          -----------     -----------     --------       ---------       --------
                                           21,500,932      21,393,852       15,238        (122,318)      (107,080)
                                          -----------     -----------     --------       ---------       --------
                                          $47,507,916     $47,482,506     $102,039       ($127,449)      $(25,410)
                                          ===========     ===========     ========       =========       ========

</TABLE>


        The aggregate net unrealized loss of $25,410 has been included as a
reduction of stockholders' equity at June 30, 1996.


5.      Stock and Warrant Agreement

        On April 15, 1996 Amgen Inc. purchased from the Company 3 million shares
of Common Stock for $48.0 million. The purchase price also included warrants to
purchase an additional 700,000 shares of Common Stock at an exercise price of
$16.00 per share. The warrants are fully exercisable, expire on April 15, 2001,
and are subject to antidilution provisions.


6.      Collaboration Agreement


        On June 27, 1996, the Company and Medtronic, Inc. (Medtronic) entered
into a worldwide exclusive joint development agreement (the Medtronic Agreement)
to collaborate on research and development of a family of therapeutics for
central nervous system diseases and disorders using experimental Regeneron
compounds and Medtronic delivery systems. The Medtronic Agreement, among other
things, provides for the Company and Medtronic to fund development costs and
supply amounts of drug and delivery systems, respectively. In addition,
Medtronic is required to make payments to Regeneron if certain clinical
milestones are achieved and the Company is required to pay royalties to
Medtronic based upon net sales of any drug developed under the collaboration.
The Medtronic Agreement may be terminated by written agreement of both parties,
by either party if certain regulatory approvals have not been obtained within
specified time periods, or by either party under certain other conditions.

        In addition, on June 27, 1996, Medtronic purchased from the Company
460,500 shares of Common Stock for $10.0 million. The purchase price also
included warrants to purchase an additional 107,400 shares of Common Stock at
an exercise price of $21.72 per share. The number of shares issuable upon
exercise of these warrants is subject to reduction in the event that Medtronic
elects a cashless exercise option. The warrants are fully exercisable, expire
on June 26, 2001, and are subject to antidilution provisions.


                                                7


<PAGE>

7.      Capital Leases

        In June 1996, the Company executed a new leasing agreement (the New
Lease Line) which provides up to $3.0 million to finance equipment
acquisitions and certain building improvements, as defined, (collectively, the
Equipment). The Company may utilize the New Lease Line in increments
(leases). Lease terms are for four years after which the Company is required
to purchase the Equipment at defined amounts, or the leases will be renewed for
eight months at defined monthly payments after which the Company will own the
Equipment. At June 30, 1996, the Company had available approximately $2.2
million of the New Lease Line.

                                       8




<PAGE>


I
tem 2.  Management's Discussion and Analysis of Financial Condition and Results
of Operations


General

        Overview. The discussion below contains forward-looking statements that
involve risks and uncertainties relating to the future financial performance of
Regeneron Pharmaceuticals, Inc. (Regeneron or the Company) and actual events or
results may differ materially. These statements concern, among other things, the
possible therapeutic applications of the Company's product candidates and
research programs, the timing and nature of the Company's clinical and research
programs now underway or planned, a variety of items described herein and in the
footnotes to the Company's financial statements (including the useful life of
assets, the anticipated length of agreements, and other matters), and the future
uses of capital and financial needs of the Company. These statements are made by
the Company based on management's current beliefs and judgment. In evaluating
such statements, stockholders and investors should specifically consider the
various factors identified under the caption Factors That May Affect Future
Operating Results which could cause actual results to differ materially from
those indicated by such forward-looking statements.

        During the second quarter of 1996, Amgen Inc. (Amgen), on behalf of
Amgen-Regeneron Partners, continued to conduct a Phase III clinical trial
designed to determine the safety and efficacy of brain-derived neurotrophic
factor (BDNF) in the treatment of amyotrophic lateral sclerosis (ALS, commonly
known as Lou Gehrig's disease). In addition, Amgen, on behalf of Amgen-Regeneron
Partners, continued to conduct a Phase I/II clinical trial of neurotrophin-3
(NT-3) for the treatment of peripheral neuropathies caused by diabetes. Amgen
also continued to conduct a trial of BDNF in Europe for the treatment of
neuropathies caused by diabetes. The Company continued to develop and
manufacture BDNF for use by Sumitomo Pharmaceuticals Co., Ltd. (Sumitomo
Pharmacteuticals) in Japan and continued the development of a series of
preclinical research programs in the areas of inflammatory and muscle disease,
angiogenesis, hematopoiesis, and cancer.

        In April 1996, Amgen purchased from the Company 3 million shares of
Common Stock for $48.0 million. The purchase price also included five-year
warrants to purchase an additional 700,000 shares of Common Stock at an exercise
price of $16.00 per share. In June 1996, the Company entered into a worldwide
exclusive joint development agreement with Medtronic, Inc. (Medtronic) to
collaborate on research and development of a family of therapeutics for central
nervous system diseases and disorders using experimental Regeneron compounds and
Medtronic delivery systems. The initial target of the Medtronic collaboration
will be the development of Regeneron's second generation neurotrophic factor
AXOKINE(TM) for the potential treatment of Huntington's disease, using 
Medtronic's implantable pump to infuse AXOKINE into the brain. In addition,
Medtronic purchased from the Company 460,500 shares of Common Stock for $10.0
million. The purchase price also included five-year warrants to purchase an
additional 107,400 shares of Common Stock at an exercise price of $21.72 per
share.


        The results of the BDNF Phase III clinical trial for ALS are uncertain
and are not expected to be known until the trial is completed and the data
reviewed and analyzed. The Company believes that such results are likely to be
known during the first quarter of 1997. If the study is timely completed and
demonstrates a statistically significant and 

                                       9


<PAGE>


clinically effective and safe treatment regimen, it could have a materially
beneficial effect on the Company. However, if the trial is not conclusively
successful, it could have a materially adverse effect on the Company, the price
of the Company's Common Stock, and the Company's ability to raise additional
capital. The results of the Company's and its collaborators' past activities in
connection with the research and development of BDNF and NT-3 do not necessarily
predict the results or success of future activities including, but not limited
to, any additional preclinical or clinical studies of BDNF or NT-3. The Company
cannot predict whether, when, or under what conditions BDNF or NT-3 will be
shown to be safe or effective to treat any human condition or be approved for
marketing by any regulatory agency. The delay or failure of current or future
studies to demonstrate the safety or efficacy of BDNF or NT-3 to treat human
conditions or to be approved for marketing would have a material adverse impact
on the Company.

        The potential success of the BDNF clinical trial is also dependent
upon, among other things, certain factors that could undermine the significance
of the data collected from such patients. Patients who are taking riluzole, an
orally administered drug approved for the treatment of ALS, are not, on that
basis, ineligible to participate in the BDNF clinical trial, and Amgen and the
Company know that some patients who are taking riluzole have enrolled in the
BDNF trial. The clinical effects of taking both drugs are completely unknown
and therefore unanticipated effects could complicate the trial or render the
data collected difficult to analyze or interpret. Amgen, on behalf of
Amgen-Regeneron Partners, has designed the BDNF clinical trial to take into
account the inclusion of patients who may also be taking riluzole. However, if
the Phase III clinical study is compromised through the inclusion of patients
who are taking riluzole or other medications, with or without the consent or
knowledge of the trial sponsor, the results of the study may be undermined and
additional clinical studies may be required, causing a delay in, and increasing
the costs of, the development of BDNF, which would have a material adverse
effect on the Company.

        No assurance can be given that extended administration of NT-3 will be
safe or effective. The Phase I study of NT-3 in normal human volunteers that
concluded in 1995 was a short term (seven day) treatment study. The 1996 study
involves substantially longer treatment (six months or longer). In the Phase I
study, two out of the seventy-six patients developed significant abnormalities
of blood tests of their liver function. These laboratory abnormalities reversed
after cessation of treatment and were not associated with any other evidence of
liver dysfunction. Similar abnormalities have not been observed in preclinical
toxicology studies with NT-3. However, if such abnormalities were to occur in a
number of patients in subsequent trials, including the 1996 study, this result

could delay or preclude the further development of NT-3. The treatment of
peripheral neuropathies associated with cancer chemotherapies or diabetes may
present additional clinical trial risks, in light of the complex and not wholly
understood mechanisms of action that lead to the neuropathies, the presence of
many other drugs to treat the underlying conditions, the potential difficulty
of achieving significant clinical endpoints, and other factors. No assurance
can be given that these or any other studies of NT-3 will be successful or that
NT-3 will be commercialized.

        To date, Regeneron has not received any revenues from the commercial
sale of products and does not expect to receive any such revenues for at least
several years. Before such revenues can be realized, the Company must overcome
a number of hurdles which include successfully completing its research and
development efforts and obtaining regulatory approval from the United States
Food and Drug Administration (FDA) or regulatory authorities in other
countries. In addition, the biotechnology and pharmaceutical industries are
rapidly evolving and highly competitive, and new developments may render the
Company's products and technologies noncompetitive and obsolete. While the
Company has applied for or received a number of patents to protect its
intellectual properties, there can be no assurance that the patents 

                                      10


<PAGE>

will be enforceable or will provide protection against competing technology. In
the absence of revenues from commercial product sales or other sources (the
amount, timing, nature, or source of which can not be predicted), the Company's
losses will continue as the Company conducts its research and development
activities. The Company's activities may expand over time and may require
additional resources, and the Company's operating losses may be substantial over
at least the next several years. The Company's losses may fluctuate from quarter
to quarter and will depend, among other factors, on the timing of certain
expenses and on the progress of the Company's research and development efforts.


Results of Operations

        Three months ended June 30, 1996 and 1995. The Company's total revenue
for the second quarter of 1996 was $6.2 million compared to $7.6 million for
the same period in 1995. Contract research and development revenue decreased to
$4.6 million for the second quarter of 1996 from $6.8 million for the same
period in 1995. Contract research and development revenue earned from Sumitomo
Pharmaceuticals decreased to $3.1 million in the second quarter of 1996 from
$4.9 million for the same period in 1995. Of the second quarter 1996 Sumitomo
Pharmaceuticals revenue, $0.8 million was for contract research and $2.3
million was reimbursement for developing manufacturing processes for, and
supplying, BDNF. Of the second quarter 1995 Sumitomo Pharmaceuticals revenue,
$3.2 million was for contract research (including $2.2 million related to a
non-recurring contract research payment) and $1.7 million was reimbursement for
developing manufacturing processes for, and supplying, BDNF. Contract research
and development revenue earned from Amgen and Amgen-Regeneron Partners (the
Partnership) decreased to $1.5 million for the second quarter of 1996 from
$1.9 million for the same period in 1995. This reflects a decision by the
Partnership to focus more spending in 1996 on clinical trials and other
precommercial activities conducted by Amgen and less spending on preclinical

research conducted by Regeneron. During the third quarter of 1995, the Company
entered into a long-term manufacturing agreement (the Merck Agreement) with
Merck & Co., Inc. (Merck), and contract manufacturing revenue for the second
quarter of 1996 related to this agreement totaled $0.4 million. Investment
income in the second quarter of 1996 increased to $1.1 million from $0.8
million for the same period in 1995, primarily due to increased levels of
interest-bearing investments resulting from the sale by the Company of equity
securities to Amgen in April 1996.

        The Company's total operating expenses increased to $13.8 million in
the second quarter of 1996 from $12.0 million for the same period in 1995.
Research and development expense increased to $6.8 million in the second
quarter of 1996 from $5.8 million for the same period in 1995 primarily due to
costs related to the Company's preclinical research programs, as well as the
costs of increased activity in the Rensselaer manufacturing facility related to
the Sumitomo and Merck agreements. Loss in Amgen-Regeneron Partners increased
to $3.5 million in the second quarter of 1996 from $2.8 million for the same
period in 1995, primarily due to increased costs related to clinical trials and
other precommercial activities conducted by Amgen on behalf of the Partnership.

        General and administrative expense was $1.6 million for both the second
quarters of 1996 and 1995. Interest expense decreased to $0.2 million in the
second quarter of 1996 from $0.4 million for the same period in 1995, resulting
from the expiration of capital leases during 1995 and the first six months of
1996. Other expenses of $0.1 million in the second quarter of 1996 are direct
expenses related to contract manufacturing for Merck.

                                      11


<PAGE>

        The Company's net loss for the second quarter of 1996 was $7.6 million,
or $0.31 per share, compared to a net loss of $4.4 million, or $0.22 per share,
for the same period in 1995.

        Six months ended June 30, 1996 and 1995. The Company's total revenue
for the six months ended June 30, 1996 was $11.3 million, compared to $15.5
million for the same period in 1995. Contract research and development revenue
decreased to $8.8 million for the six months ended June 30, 1996 from $13.7
million for the same period in 1995. Contract research and development revenue
earned from Sumitomo Pharmaceuticals decreased to $5.8 million in the six
months ended June 30, 1996 from $9.9 million for the same period in 1995. Of
the six months ended June 30, 1996 Sumitomo Pharmaceuticals revenue, $1.5
million was for contract research and $4.3 million was reimbursement for
developing manufacturing processes for, and supplying, BDNF. Of the six months
ended June 30, 1995, Sumitomo Pharmaceuticals revenue, $6.4 million was for
contract research (including $5.4 million related to a non-recurring contract
research payment) and $3.5 million was reimbursement for developing
manufacturing processes for, and supplying, BDNF. Contract research and
development revenue earned from Amgen and Amgen-Regeneron Partners decreased to
$3.0 million for the six months ended June 30, 1996 from $3.8 million for the
same period in 1995. This reflects a decision by the Partnership to focus more
spending in 1996 on clinical trials and other precommercial activities
conducted by Amgen and less spending on preclinical research conducted by

Regeneron. During the third quarter of 1995, the Company entered into the Merck
Agreement, and contract manufacturing revenue for the six months ended June 30,
1996 related to this agreement totaled $0.8 million. Investment income for the
six month periods ended June 30, 1996 and June 30, 1995 was $1.7 million.

        The Company's total operating expenses increased to $26.7 million in
the six months ended June 30, 1996 from $24.0 million for the same period in
1995. Research and development expense increased to $13.7 million in the six
months ended June 30, 1996 from $11.6 million for the same period in 1995
primarily due to costs related to the Company's preclinical research programs,
as well as the costs of increased activity in the Rensselaer manufacturing
facility related to the Sumitomo and Merck agreements. Loss in Amgen-Regeneron
Partners increased to $6.2 million in the six months ended June 30, 1996 from
$5.4 million for the same period in 1995, primarily due to increased costs
related to clinical trials and other precommercial activities conducted by
Amgen on behalf of the Partnership.

        General and administrative expense for the six months ended June 30,
1996 remained at the same level compared to the corresponding period in 1995.
Interest expense decreased to $0.5 million in the six months ended June 30,
1996 from $0.8 million for the same period in 1995, resulting from the
expiration of capital leases during 1995 and the first six months of 1996.
Other expenses of $0.2 million in the six months ended June 30, 1996 are direct
expenses related to contract manufacturing for Merck.

        The Company's net loss for the six months ended June 30, 1996 was $15.4
million, or $0.66 per share, compared to a net loss of $8.6 million, or $0.44
per share, for the same period in 1995.


Liquidity and Capital Resources

        Since its inception in 1988, the Company has financed its operations
primarily through private placements and public offerings of its equity
securities, revenue earned under the agreements between the Company and Amgen,
Sumitomo Chemical Company, 

                                      12


<PAGE>

Ltd., Sumitomo Pharmaceuticals, and Merck, and investment income. In connection
with the Company's agreement to collaborate with Sumitomo Pharmaceuticals in the
research and development of BDNF in Japan, Sumitomo Pharmaceuticals has paid the
Company $19.0 million and has agreed to pay the Company $3.0 million annually in
1997 and 1998. Sumitomo Pharmaceuticals has the option to cancel any remaining
annual payments; however, if such a cancellation were to occur, the rights to
develop and commercialize BDNF in Japan would revert to the Company. In
addition, the Company is being reimbursed in connection with supplying Sumitomo
Pharmaceuticals with BDNF for preclinical use.

        Under the Amgen Agreement, Amgen was required to make defined payments
through June 1995 to the Company for research and development efforts in the
United States in connection with BDNF and NT-3. As provided in the Amgen

Agreement, after Amgen determined that Investigational New Drug applications
(IND) should be filed for BDNF and NT-3, Amgen and Regeneron created
Amgen-Regeneron Partners to conduct the development and commercialization of
these product candidates. The Partnership began operations in June 1993 with
respect to BDNF and in January 1994 with respect to NT-3. Amgen's required
payments for BDNF and NT-3 were made directly to Regeneron prior to the
determination by Amgen that the preparation of an IND for each compound should
commence and thereafter to the Partnership. The Company's further activities
relating to BDNF and NT-3, as agreed upon by Amgen and Regeneron, are being
reimbursed by the Partnership, and the Company recognizes such reimbursement as
revenue. The funding of the Partnership,is through capital contributions from
Amgen and Regeneron, who must make equal payments in order to maintain equal
ownership and equal sharing of any profits or losses from the partnership. The
Company has made capital contributions totaling $34.9 million to Amgen-Regeneron
Partners from the Partnership's inception in June 1993 through June 30, 1996.
The Company expects that its capital contributions in 1996 will total
approximately $15.5 million. These contributions could increase, depending upon
the results of the BDNF ALS clinical trial and the other BDNF and NT-3 studies,
among other things. Capital contributions beyond 1996 are anticipated to be
significant.

        In September 1995, the Company entered into the Merck Agreement.
Depending on the volume of the intermediate supplied to Merck, total capital
and product payments from Merck to Regeneron could total $40.0 million or more
over the term of the agreement, which is expected to extend to 2003. This
agreement may be terminated at any time by Merck upon the payment by Merck of a
termination fee.

        From its inception in January 1988 through June 30, 1996 the Company
has invested $50.1 million in property, plant and equipment, including $16.8
million to acquire and renovate the Rensselaer facility and $10.5 million of
construction in progress to modify the facility in connection with the Merck
Agreement. In connection with the purchase and renovation of the Rensselaer
facility, the Company obtained financing of $2.0 million from the New York
State Urban Development Corporation, of which $1.9 million was outstanding at
June 30, 1996. Under the terms of such financing, the Company is not permitted
to declare or pay dividends to its stockholders.

        In June 1996, the Company executed a new leasing agreement (the New
Lease Line) which provides up to $3.0 million to finance equipment
acquisitions and certain building improvements, as defined, (collectively, the
Equipment). The Company may utilize the New Lease Line in increments
(leases). Lease terms are for four years after which the Company is required
to purchase the Equipment at defined amounts, or the leases will be renewed for
eight months at defined monthly payments after which the Company will own the
Equipment. At June 30, 1996, the Company had available approximately $2.2
million of the New Lease Line.

                                      13


<PAGE>

        The Company expects that expenses related to the filing, prosecution,
defense and enforcement of patent and other intellectual property claims will
continue to be substantial as a result of patent filings and prosecutions in

the United States and foreign countries. The Company is currently involved in
two interference proceedings in the Patent and Trademark Office between
Regeneron's patent applications and patents relating to CNTF issued to
Synergen, Inc. Amgen acquired all outstanding shares of Synergen in 1994.

        As of June 30, 1996, the Company had no established banking
arrangements through which it could obtain short-term financing or a line of
credit. Additional funds may be raised through, among other things, the
issuance of additional securities, other financing arrangements, and future
collaboration agreements. No assurance can be given that additional financing
will be available or, if available, that it will be available on acceptable
terms. In April 1996 Amgen purchased from the Company 3 million shares of
Common Stock for $48.0 million. The purchase price also included warrants to
purchase an additional 700,000 shares at an exercise price of $16.00 per share.
In June 1996, Medtronic purchased from the Company 460,500 shares of Common
Stock for $10.0 million. The purchase price also included warrants to purchase
an additional 107,400 shares of Common Stock at an exercise price of $21.72 per
share.

        At June 30, 1996, the Company had $96.3 million in cash, cash
equivalents, and marketable securities. The Company expects to incur
substantial funding requirements for capital contributions to Amgen-Regeneron
Partners to support the continued development and clinical trials of BDNF and
NT-3. The Company also expects to incur substantial funding requirements for,
among other things, its research and development activities (including
preclinical and clinical testing), validation of its manufacturing facilities,
and the acquisition of equipment, and may incur substantial funding
requirements for expenses related to the patent interference proceedings and
other patent matters. The amount needed to fund operations will also depend on
other factors, including the status of competitive products, the success of the
Company's research and development programs, the status of patents and other
intellectual property rights developments, and the extent and success of any
collaborative research programs. The Company expects to incur substantial
capital expenditures in connection with the renovation and validation of its
Rensselaer facility pursuant to its manufacturing agreement with Merck.
However, the Company also expects that such expenditures will be substantially
reimbursed by Merck, subject to certain conditions. The Company believes that
its existing capital resources will enable it to meet operating needs through
the next several years. No assurance can be given that there will be no change
in projected revenues or expenses that would lead to the Company's capital
being consumed at a faster rate than currently expected.


Factors That May Affect Future Operating Results

        Regeneron cautions stockholders and investors that the following
important factors, among others, in some cases have affected, and in the future
could affect, Regeneron's actual results and could cause Regeneron's actual
results to differ materially from those expressed in any forward-looking
statements made by, or on behalf of, Regeneron. The statements under this
caption are intended to serve as cautionary statements within the meaning of
the Private Securities Litigation Reform Act of 1995. The following information
is not intended to limit in any way the characterization of other statements or
information under other captions as cautionary statements for such purpose:


                                      14


<PAGE>

o      Delay, difficulty, or failure in obtaining regulatory approval (including
       approval of its facilities for production) for the Company's products
       (including vaccine intermediate for Merck), including delays or
       difficulties in development because of insufficient proof of safety or
       efficacy.

o      Delay, difficulty, or failure of the Company's preclinical drug research
       and development programs to produce product candidates that are
       scientifically or commercially appropriate for further development by the
       Company or others.

o      Increased and irregular costs of development, regulatory approval,
       manufacture, sales, and marketing associated with the introduction of
       products in the late stage of development.

o      Difficulties in launching or marketing the Company's products by the
       Company or its licensees, especially when such products are novel
       products based on biotechnology, and unpredictability of customer
       acceptance of such products.

o      Lack of experience with the ALS or peripheral neuropathy patient
       population and customer base in the United States could lead to a 
       variety of materially adverse developments; other factors that could
       materially affect the Company's future potential commerical sales or
       success of BDNF and NT-3 include the timing, approval, market launch and
       potential commercialization of competing products, including riluzole (an
       approved orally active product for ALS marketed by Rhone Poulenc Rorer)
       and insulin-like growth factor (a product being developed by Chiron
       Corporation and Cephalon Corp., which the Company believes will be the
       subject of a license application to the FDA in 1996); pricing,
       promotional, and marketing decisions (and the implementation of such
       decisions) by the Company and its partner, Amgen; and reimbursement
       policies of health care providers and insurers.

o      The ability to obtain, maintain, and prosecute intellectual property
       rights, and the cost of acquiring in-process technology and other
       intellectual property rights, either by license, collaboration, or
       purchase of another entity.

o      Amount and rate of growth in Regeneron's selling, general and
       administrative expenses; and the impact of unusual or infrequent charges
       resulting from Regeneron's ongoing evaluation of its business strategies
       and organizational structure.

o      Failure of corporate partners to commercialize successfully the Company's
       products or to retain and expand the markets served by the commercial
       collaborations; conflicts of interest, priorities, and commercial
       strategies which may arise between the Company and such corporate
       partners.


o      Inability to maintain or initiate third party arrangements which generate
       revenues, in the form of license fees, research and development support,
       royalties, and other payments, in return for rights to technology or
       products under development by the Company.

o      Delays or difficulties in developing and acquiring production technology
       and technical and managerial personnel to manufacture novel biotechnology
       products in commercial quantities at reasonable costs and in compliance
       with applicable quality assurance and environmental regulations and
       governmental permitting requirements.

                                      15


<PAGE>

o      Difficulties in obtaining key raw materials and supplies for the
       manufacture of the Company's products.

o      The costs and other effects of legal and administrative cases and
       proceedings (whether civil, such as product-related or environmental, or
       criminal); settlements and investigations; developments or assertions by
       or against Regeneron relating to intellectual property rights and
       licenses; the issuance and use of patents and proprietary technology by
       Regeneron and its competitors, including the possible negative effect on
       the Company's ability to develop, manufacture, and sell its products in
       circumstances where it is unable to obtain licenses to patents which may
       be required for such products.

o      Underutilization of the Company's existing or new manufacturing 
       facilities or of any facility expansions, resulting in inefficiencies and
       higher costs; start-up costs, inefficiencies, delays, and increased
       depreciation costs in connection with the start of production in new
       plants and expansions.

o      Health care reform.

o      The ability to attract and retain key personnel.

                                      16




<PAGE>


P
ART II. OTHER INFORMATION


ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

        On June 28, 1996, the Company conducted its Annual Meeting of
Shareholders pursuant to due notice. A quorum being present either in person or
by proxy, the shareholders voted on the following matters:

        1. To elect three directors to hold office for a three-year term as
Class II directors, and until their successors are duly elected and qualified.

        2. To approve certain changes to bring the Company's Amended and
Restated 1990 Long-Term Incentive Plan into compliance with Section 162(m) of
the Internal Revenue Code of 1986, as amended and any regulations thereunder.

        3.  To approve the selection of Coopers & Lybrand L.L.P. as independent
 accountants for the Company's fiscal year ending December 31, 1996.

        No other matters were voted on. The number of votes cast was:

                                              For           Withhold Authority
                                              ---           ------------------
1.  Election of Class II Directors
        James W. Fordyce                   63,947,872            202,916
        Alfred G. Gilman, M.D., Ph.D.      63,741,672            409,116
        Joseph L. Goldstein, M.D.          63,946,772            204,016

        The terms of office of P. Roy Vagelos, M.D., Leonard S. Schleifer, M.D.,
Ph.D., Eric M. Shooter, Ph.D., George L. Sing, Charles A. Baker, and Michael S.
Brown, M.D. continued after the meeting.


                                      For             Against         Abstain
                                      ---             -------         ------- 
2.  Amendment of Long-Term
    Incentive Plan                 62,651,196         399,655         79,881

3.  Selection of accountants       64,107,261          22,366         21,161

                                      17     


<PAGE>


ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

        (a)     Exhibits

                10.1    Stock and Warrant Purchase Agreement dated as of April
                        15, 1996, between the Company and Amgen Inc.

                10.2    Warrant Agreement dated as of April 15, 1996, between

                        the Company and Amgen Inc.

                10.3    Registration Rights Agreement dated as of April 15,
                        1996, between the Company and Amgen Inc.

                10.4    Stock and Warrant Purchase Agreement dated as of June
                        27, 1996, between the Company and Medtronic, Inc.

                10.5    Warrant Agreement dated as of June 27, 1996, between
                        the Company and Medtronic, Inc.

                10.6    Registration Rights Agreement dated as of June 27,
                        1996, between the Company and Medtronic, Inc.

                10.7    Assignment and Assumption Agreement dated as of June
                        27, 1996, between the Company and Medtronic, Inc.

                11      Statement of computation of loss per share for the
                        three months and six months ended June 30, 1996 and
                        1995.

                27      Financial Data Schedule



        (b)     Reports

                No reports on Form 8-K were filed by the registrant during the
                quarter ended June 30, 1996.

                                      18




<PAGE>


                                   SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                  Regeneron Pharmaceuticals, Inc.




Date: August 14, 1996             By: /s/ Murray A. Goldberg
                                      -------------------------------
                                      Murray A. Goldberg
                                      Vice President, Finance & Administration,
                                      Chief Financial Officer, and Treasurer

                                      19







<PAGE>
================================================================================

                      STOCK AND WARRANT PURCHASE AGREEMENT

                                 by and between

                         REGENERON PHARMACEUTICALS, INC.

                                       AND

                                   AMGEN INC.




                           DATED AS OF: APRIL 15, 1996

================================================================================

<PAGE>

                                TABLE OF CONTENTS


                                                                          PAGE


ARTICLE I      DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . .  1

    1.1  Defined Terms . . . . . . . . . . . . . . . . . . . . . . . . . .  1
    1.2  Other Defined Terms . . . . . . . . . . . . . . . . . . . . . . .  2

ARTICLE II    ISSUANCE AND SALE OF SECURITIES. . . . . . . . . . . . . . .  3

    2.1  Issuance and Sale of Securities . . . . . . . . . . . . . . . . .  3

ARTICLE III   CLOSING. . . . . . . . . . . . . . . . . . . . . . . . . . .  3

    3.1  Closing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
    3.2  Documents to be Delivered . . . . . . . . . . . . . . . . . . . .  3

ARTICLE IV    REPRESENTATIONS AND WARRANTIES OF THE COMPANY. . . . . . . .  4

    4.1  Organization and Standing . . . . . . . . . . . . . . . . . . . .  4
    4.2  Capitalization. . . . . . . . . . . . . . . . . . . . . . . . . .  4
    4.3  Issuance of Shares. . . . . . . . . . . . . . . . . . . . . . . .  5
    4.4  Authority for Agreement . . . . . . . . . . . . . . . . . . . . .  5
    4.5  Governmental Consents . . . . . . . . . . . . . . . . . . . . . .  6
    4.6  Litigation. . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
    4.7  SEC Filings; Financial Statements . . . . . . . . . . . . . . . .  6
    4.8  No Undisclosed Liabilities. . . . . . . . . . . . . . . . . . . .  7
    4.9  Absence of Changes. . . . . . . . . . . . . . . . . . . . . . . .  7
    4.10 Intellectual Property . . . . . . . . . . . . . . . . . . . . . .  7
    4.11 No Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . .  8

    4.12 Offerings . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
    4.13 Brokers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
    4.14 Clinical Trials . . . . . . . . . . . . . . . . . . . . . . . . .  8

ARTICLE V      REPRESENTATIONS AND WARRANTIES OF BUYER . . . . . . . . . .  8

    5.1  Investment. . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
    5.2  Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
    5.3  Accredited Investor . . . . . . . . . . . . . . . . . . . . . . .  9
    5.4  Brokers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
    5.5  Clinical Trials . . . . . . . . . . . . . . . . . . . . . . . . .  9



                                        i

<PAGE>

ARTICLE VI    INDEMNIFICATION. . . . . . . . . . . . . . . . . . . . . . .  9

    6.1  Survival of Representations, Etc. . . . . . . . . . . . . . . . .  9
    6.2  Indemnification . . . . . . . . . . . . . . . . . . . . . . . . . 10

ARTICLE VII   MISCELLANEOUS. . . . . . . . . . . . . . . . . . . . . . . . 10

    7.1  Legend. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
    7.2  Assignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
    7.3  Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
    7.4  Choice of Law . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.5  Entire Agreement; Amendments and Waivers. . . . . . . . . . . . . 12
    7.6  Counterparts. . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.7  Invalidity. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.8  Headings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.9  Expenses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.10
 Publicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    7.11 Specific Enforcement. . . . . . . . . . . . . . . . . . . . . . . 13
    7.12 Further Assurances. . . . . . . . . . . . . . . . . . . . . . . . 13
    7.13 Section 912 of the New York Business Corporate Law. . . . . . . . 13


                                       ii

<PAGE>

                      STOCK AND WARRANT PURCHASE AGREEMENT

     This Stock and Warrant Purchase Agreement, dated as of April 15, 1996 is by
and between AMGEN INC., a Delaware corporation ("BUYER"), and REGENERON
PHARMACEUTICALS, INC., a New York corporation (the "COMPANY").

                                    RECITALS

     WHEREAS, Buyer wishes to purchase from the Company, and the Company wishes
to sell to Buyer, 3,000,000 shares of the Company's Common Stock (the "SHARES");

     WHEREAS, Buyer wishes to purchase from the Company, and the Company wishes

to sell to Buyer, pursuant to the terms and conditions of the Warrant Agreement
(the "WARRANT AGREEMENT"), 700,000 Warrants (the "WARRANTS," and together with
the Shares, the "SECURITIES"). Each of the Warrants shall be exercisable for one
share of Common Stock (individually, a "WARRANT SHARE" and collectively, the
"WARRANT SHARES"); and

     WHEREAS, Buyer and the Company desire to provide for the foregoing
purchases and sales and to establish various rights and obligations in
connection therewith.

                                    AGREEMENT

     NOW, THEREFORE, in consideration of the mutual covenants and promises
contained herein and for other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

     1.1 DEFINED TERMS. As used herein, the terms below shall have the following
meanings:

          "BDNF" shall mean brain-derived neurotrophic factor.

          "CLASS A COMMON STOCK" shall mean the shares of the Class A Common
Stock, par value $.001 per share, of the Company.

          "COLLATERAL AGREEMENTS" shall mean the Warrant Agreement and the
Registration Rights Agreement.

<PAGE>

          "COMMON STOCK" shall mean the shares of the Common Stock, par value
$.001 per share, of the Company.

          "COMMISSION" shall mean the Securities and Exchange Commission.

          "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission thereunder.

          "NT3" shall mean Neurotrophin - 3.

          "PERSON" shall mean any individual, firm, corporation, partnership,
limited liability company, trust, unincorporated organization or other entity or
a government or agency or political subdivision thereof, and shall include any
successor (by merger or otherwise) of such Person.

          "PREFERRED STOCK" shall mean the shares of the Preferred Stock, par
value $.001 per share, of the Company.

          "REGISTRATION RIGHTS AGREEMENT" shall mean the Registration Rights
Agreement to be entered into as of the date hereof by and between the Company
and Buyer.


          "SECURITIES ACT" shall mean the Securities Act of 1933, as amended,
and the rules and regulations of the Commission thereunder.

          "WARRANT AGREEMENT" shall mean the Warrant Agreement to be entered
into as of the date hereof by and between the Company and Buyer.

     1.2 OTHER DEFINED TERMS. The following terms shall have the meanings
defined for such terms in the Sections set forth below:


                                        2

<PAGE>

         TERM                                    SECTION
         ----                                    -------
         Buyer                                   Preamble
         Closing                                   3.1
         Company SEC Reports                       4.7
         Reserved Plan Shares                      4.2
         Securities                              Recitals
         Securities Purchase Price                 2.1
         Shares                                  Recitals
         Warrant Agreement                       Recitals
         Warrants                                Recitals
         Warrant Share                           Recitals
         Warrant Shares                          Recitals
         1995 Balance Sheet                        4.8


                                   ARTICLE II

                         ISSUANCE AND SALE OF SECURITIES

     2.1 ISSUANCE AND SALE OF SECURITIES. Upon the terms set forth herein, the
Company will issue and sell to Buyer, and Buyer will purchase from the Company,
the Shares and the Warrants for an aggregate price of $48 Million in immediately
available funds (the "SECURITIES PURCHASE PRICE").

                                   ARTICLE III

                                     CLOSING

     3.1 CLOSING. The closing of the transactions contemplated hereby (the
"CLOSING") will take place at the offices of Skadden, Arps, Slate, Meagher &
Flom, 919 Third Avenue, New York, New York 10022 at 5:00 p.m. New York time on
the date hereof.

     3.2 DOCUMENTS TO BE DELIVERED. At the Closing, the Company shall deliver to
Buyer, against payment in full of the Securities Purchase Price, (i)
certificates for the Shares in such denominations as Buyer has requested, dated
the date hereof and registered in the names requested by Buyer, (ii)
certificates for the Warrants in such denominations as Buyer has requested,
dated the date hereof and registered in the names requested by Buyer, (iii) each
of the Collateral Agreements, which shall have been duly authorized, executed

and delivered by the Company and shall be in full


                                        3

<PAGE>

force and effect and (iv) an opinion of Paul Lubetkin, General Counsel to the
Company, in form and substance reasonably satisfactory to Buyer, substantially
to the effect specified in SECTIONS 4.1 THROUGH 4.5, with such exceptions and
qualifications as are customary and reasonable under the law of the applicable
jurisdiction.  In rendering such opinion, such counsel may rely upon
certificates of public officers and, as matters of fact, upon certificates of
duly authorized representatives of the Company, PROVIDED, that copies of such
certificates shall be contemporaneously delivered to Buyer.


                                   ARTICLE IV

                        REPRESENTATIONS AND WARRANTIES OF
                                   THE COMPANY

     The Company hereby represents and warrants to Buyer as of the date hereof
as follows:

     4.1 ORGANIZATION AND STANDING. The Company is a corporation duly organized
and validly existing under the laws of the State of New York and has full
corporate power and authority to own and lease its property, to conduct its
business as presently conducted and as proposed to be conducted by it and to
execute and deliver this Agreement and each of the Collateral Agreements. The
Company has full corporate power and authority to perform and to carry out the
transactions contemplated by this Agreement and each of the Collateral
Agreements. The Company is qualified to do business and in good standing in New
York and in each jurisdiction where it does business or owns property except
those jurisdictions where the failure to be so qualified and in good standing
would not have a material adverse effect on its business or property. The
Company has furnished to Buyer true and complete copies of its Restated
Certificate of Incorporation and Bylaws, each as amended to date and presently
in effect.

     4.2 CAPITALIZATION. As of April 12, 1996, the authorized capital stock of
the Company consisted of the following: (a) 60,000,000 shares of Common Stock,
of which (i) 16,826,838 shares were issued and outstanding, (ii) 5,203,942
shares were reserved for future issuance upon conversion of the Class A Common
Stock, each share of the Class A Stock being convertible into one share of
Company Common Stock, and (iii) 3,789,626 shares were reserved for future
issuance under the Company's 1990 Amended and Restated Long-Term Incentive Plan
(the "RESERVED PLAN SHARES"); and (b) 40,000,000 shares of Class A Common Stock,
of which 5,203,942 were issued and outstanding, and (c) 30,000,000 shares of
Preferred Stock, none of which were issued and outstanding. No material change
in such capitalization has occurred between April 12, 1996 and the date hereof,
and there has been no reduction whatsoever in the 


                                       4


<PAGE>

number of shares of any class of the Company's outstanding capital stock. All of
the issued and outstanding shares of Common Stock, Class A Stock, and Preferred
Stock have been duly authorized, and all of the issued and outstanding shares of
the Common Stock and the Class A Common Stock are validly issued and are fully
paid and non-assessable. Except as set forth in the Company SEC Reports hereto
or as provided in this Agreement, there is not, nor upon the consummation of the
transactions contemplated herein, will there be, (i) any subscription, warrant,
option, convertible security or other right (contingent or otherwise) to
purchase or acquire any shares of capital stock of the Company, (ii) any
commitment of the Company to issue any subscription, warrant, option,
convertible security or other such right or to issue or distribute to holders of
any shares of its capital stock any evidences of indebtedness or assets of the
Company, or (iii) any obligation of the Company (contingent or otherwise) to
purchase, redeem or otherwise acquire any shares of its capital stock or any
interest therein or to pay any dividend or make any other distribution in
respect thereof. Except as set forth in the Company SEC Reports or as provided
in this Agreement, no Person is entitled to, nor upon the consummation of the
transactions contemplated herein will any Person be entitled to, (i) any
preemptive or similar right with respect to the issuance of any capital stock of
the Company, or (ii) any rights with respect to the registration of any capital
stock of the Company under the Securities Act.

     4.3 ISSUANCE OF SHARES. The issuance, sale and delivery of the Securities
in accordance with this Agreement, and the issuance and delivery of the Warrant
Shares issuable upon exercise of the Warrants, have been duly authorized and
reserved for issuance, as the case may be, by all necessary corporate action on
the part of the Company (no consent or approval of the stockholders of the
Company being required by law, by the Restated Certificate of Incorporation or
Bylaws of the Company, or the qualification criteria of the Nasdaq National
Market), and the Securities when so issued, sold and delivered against payment
therefor in accordance with the provisions of this Agreement, and the Warrant
Shares issuable upon exercise of the Warrants, when issued upon such exercise,
will be duly and validly issued, fully paid and non-assessable and not subject
to preemptive or any other similar rights of the shareholders of the Company or
others and free, at time of issuance, of all restrictions on transfer subject to
restrictions on transfer imposed by applicable federal and state securities
laws.

     4.4 AUTHORITY FOR AGREEMENT. The execution, delivery and performance by the
Company of this Agreement and each of the Collateral Agreements have been duly
authorized by all necessary corporate action, and this Agreement and each of the
Collateral Agreements have been duly executed and delivered and constitute valid
and binding obligations of the Company enforceable in accordance with their
respective terms, subject to bankruptcy or equitable laws that might affect the
enforceability of this Agreement and each of the Collateral Agreements. The
execution 


                                       5

<PAGE>

and delivery by the Company of this Agreement and each of the Collateral

Agreements, and the consummation by the Company of the transactions contemplated
hereby and thereby (including, without limitation, the issuance and sale of the
Securities and the Warrant Shares), will not violate any provision of law and
will not conflict with or result in any breach of any of the terms, conditions
or provisions of, or constitute a default under, or result in the creation of
any lien, security interest, charge or encumbrance upon any of the properties,
assets or outstanding capital stock of the Company, under the Company's Restated
Certificate of Incorporation, or Bylaws, or any indenture, lease, agreement or
other instrument to which the Company is a party or by which it or any of its
properties is bound, or any decree, judgement, order, statute, rule or
regulation applicable to the Company.

     4.5 GOVERNMENTAL CONSENTS. No consent, approval, order or authorization of,
or registration, qualification, designation, declaration or filing with, any
governmental or regulatory authority is required on the part of the Company in
connection with the execution and delivery of this Agreement and each of the
Collateral Agreements, and the consummation of the transactions contemplated
hereby and thereby (including, without limitation, the offer, issue, sale and
delivery of the Securities and the Warrant Shares issuable upon exercise of the
Warrants), except such filings as shall have been made or consents or approvals
obtained prior to and which shall be effective on and as of the Closing. Based
in part on the representations made by Buyer in ARTICLE V of this Agreement, the
offer and sale of the Securities to Buyer will be in compliance with applicable
federal and state securities laws.

     4.6 LITIGATION. Except as set forth in the Company SEC Reports, there are
no material actions, suits, proceedings or investigations, either at law or in
equity, or before any commission or other administrative authority in any United
States or foreign jurisdiction, of any kind now pending or, to the best of the
Company's knowledge, threatened or proposed involving the Company or any of its
properties or assets or which questions the validity or legality of the
transactions contemplated hereby, or to the Company's actual knowledge, against
its employees or consultants with respect to the Company's business.

     4.7 SEC FILINGS; FINANCIAL STATEMENTS. (a) The Company has filed all forms,
reports and documents required to be filed with the Commission since April 1,
1993 (collectively, the "COMPANY SEC REPORTS"). The Company SEC Reports (i) were
prepared in all material respects in accordance with the requirements of the
Securities Act or the Exchange Act, as the case may be, and (ii) did not at the
time they were filed (or if amended or superseded by a filing prior to the date
of this Agreement, then on the date of such filing) contain any untrue statement
of a material fact or omit to state a material fact required to be stated
therein or necessary in order 


                                       6

<PAGE>

to make the statements therein, in the light of the circumstances under which
they were made, not misleading.

     (b) Each of the financial statements (including, in each case, any related
notes thereto) contained in the Company SEC Reports was prepared in accordance
with generally accepted accounting principles applied on a consistent basis

throughout the periods involved (except as may be indicated in the notes
thereto), and each was complete and correct in all material respects and
presented fairly in all material respects presented the financial position of
the Company as at the respective dates thereof and the results of its operations
and cash flows for the periods indicated, except that the unaudited interim
financial statements were or are subject to normal and recurring year-end
adjustments which were not or are not expected to be material in amount.

     4.8 NO UNDISCLOSED LIABILITIES. The Company does not have any material
liabilities (absolute, accrued, contingent or otherwise) except liabilities (a)
in the aggregate adequately provided for in the Company's audited balance sheet
(including any related notes thereto) for the fiscal year ended December 31,
1995 included in the Company's Annual Report on Form 10-K for the fiscal year
ended December 31, 1995 (the "1995 BALANCE SHEET"), or (b) incurred since
December 31, 1995 in the ordinary course of business.

     4.9 ABSENCE OF CHANGES. Since December 31, 1995, there has been no material
adverse change in the financial condition, business, or assets of the Company.

     4.10 INTELLECTUAL PROPERTY.

     (a) To the best of the Company's knowledge, it has done nothing to
compromise the secrecy, confidentiality or value of any of its trade secrets,
know-how, inventions, prototypes, designs, processes or technical data required
to conduct its business as now conducted or as proposed to be conducted. The
Company will continue to take reasonable security measures in the future, as it
presently is doing, to protect the secrecy, confidentiality, and value of all of
its trade secrets, know-how, inventions, prototypes, designs, processes, and
technical data important to the conduct of its business.

     (b) Except as set forth in the Company SEC Reports, the Company has not
granted rights to manufacture, produce, license, market or sell its products to
any other Person and is not bound by any agreement that affects the Company's
exclusive right to develop, manufacture, distribute, market or sell its
products.


                                       7

<PAGE>

     4.11 NO DEFAULTS. The Company is not in default (a) under its Restated
Certificate of Incorporation or Bylaws, each as amended or restated to date, or
any indenture, mortgage, lease agreement, contract, purchase order or other
instrument to which it is a party or by which it or any of its property is bound
or affected or (b) with respect to any order, writ, injunction or decree of any
court of any federal, state, municipal or other governmental department,
commission, board, bureau, agency or instrumentality, domestic or foreign, which
defaults, either singly or in the aggregate, would have a material adverse
effect on the Company. At the time of the Closing, to the best knowledge of the
Company, there will exist no condition, event or act which constitutes, or which
after notice, lapse of time or both would constitute, a material default under
any of the foregoing which, either singly or in the aggregate, would have a
material adverse effect on the Company.


     4.12 OFFERINGS. Except as contemplated by this Agreement or the Company's
1990 Amended and Restated Long-Term Incentive Plan or as otherwise disclosed by
the Company to Buyer, the Company does not have any current plans or intentions
to issue any shares of its capital stock or any other securities or any
securities convertible or exchangeable into shares of its capital stock or any
other securities.

     4.13 BROKERS. No broker, finder or investment banker is entitled to any
brokerage, finder's or other fee or commission in connection with the
transactions contemplated by this Agreement based upon arrangements made by or
on behalf of the Company.

     4.14 CLINICAL TRIALS. The Company is not aware of any non-public
information in the possession of its executive officers relating to the
completed or ongoing clinical trials of BDNF and/or NT3 that would be likely to
materially affect the price of the Common Stock.

                                    ARTICLE V

                     REPRESENTATIONS AND WARRANTIES OF BUYER

     Buyer hereby represents and warrants to the Company as of the date hereof
as follows:

     5.1 INVESTMENT. Buyer is acquiring the Securities, and the Warrant Shares
into which the Warrants may be exercised, for its own account (and not for the
account of others) for investment and not with a view to, or for sale in
connection with, any distribution thereof, nor with any present intention of
distributing or selling 


                                       8

<PAGE>

the same; and, except as contemplated by this Agreement, Buyer has no present or
contemplated agreement, undertaking, arrangement, obligation, indebtedness or
commitment providing for the disposition thereof.

     5.2 AUTHORITY. Buyer has full power and authority to execute and deliver
and to perform this Agreement and each of the Collateral Agreements in
accordance with their respective terms. Buyer represents that it has not been
organized, reorganized or recapitalized specifically for the purpose of
investing in the Company.

     5.3 ACCREDITED INVESTOR. Buyer is an Accredited Investor within the
definition set forth in Securities Act Rule 501(a).

     5.4 BROKERS. No broker, finder or investment banker (other than CS First
Boston, the fees and expenses of whom will be paid by Buyer) is entitled to any
brokerage, finder's or other fee or commission in connection with the
transactions contemplated by this Agreement based upon arrangements made by or
on behalf of Buyer.

     5.5 CLINICAL TRIALS. Buyer is not aware of any non-public information in

possession of its executive officers relating to the completed or ongoing
clinical trials of BDNF and/or NT3 that would be likely to materially affect the
price of the Common Stock.

                                   ARTICLE VI

                                 INDEMNIFICATION

     6.1 SURVIVAL OF REPRESENTATIONS, ETC. All representations and warranties
contained herein shall survive the execution and delivery of this Agreement and
the Collateral Agreements and the closing of the transactions contemplated
hereby and thereby until the third anniversary of the date of this Agreement (or
until final resolution of any claim or action arising from the untruth,
inaccuracy or breach of any such representation and warranty, if notice of such
untruth, inaccuracy or breach was given prior to such third anniversary) without
regard to any investigation made by any of the parties hereto. All statements
contained in any certificate or other instrument delivered by the Company
pursuant to this Agreement and denominated as representations and warranties
shall constitute representations and warranties by the Company under this
Agreement. All agreements and covenants contained herein shall survive
indefinitely until, by their respective terms, they are no longer operative.


                                       9

<PAGE>

     6.2 INDEMNIFICATION. The Company shall, with respect to the
representations, warranties, covenants and agreements made by the Company herein
or in certificates or other instruments delivered in connection therewith,
indemnify, defend and hold Buyer harmless against all liability, together with
all reasonable costs and expenses related thereto (including legal and
accounting fees and expenses), arising from the untruth, inaccuracy or breach of
any such representations, warranties, covenants or agreements of the Company.

                                   ARTICLE VII

                                  MISCELLANEOUS

     7.1 LEGEND. (a) Each certificate representing Shares sold pursuant to the
provisions hereof, if deemed advisable by the Company, shall bear the following
legends:

          "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
     UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED, SOLD
     OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL SUCH
     SHARES ARE REGISTERED UNDER SUCH ACT OR AN OPINION OF COUNSEL REASONABLY
     SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH
     REGISTRATION IS NOT REQUIRED."

     (b) Buyer hereby agrees not to offer, sell or otherwise transfer the Shares
in violation of the foregoing legend.

     7.2 ASSIGNMENT. Neither this Agreement nor any of the rights or obligations
hereunder may be assigned by the Company without the prior written consent of

Buyer, or by Buyer without the prior written consent of the Company, except that
Buyer may, without such consent, assign the right to acquire the Securities to a
wholly-owned subsidiary or subsidiaries of Buyer, each of which shall become
parties to this Agreement and each of the Collateral Agreements; provided,
however, that Buyer shall continue to be a party to this Agreement and to be
bound by the provisions hereof. Subject to the foregoing, this Agreement shall
be binding upon and inure to the benefit of the parties hereto and their
respective successors and assigns, and no other Person shall have any right,
benefit or obligation hereunder.

     7.3 NOTICES. Unless otherwise provided herein, any notice, request,
instruction or other document to be given hereunder by any party to the others
shall be 


                                       10

<PAGE>

in writing and delivered in person or by courier, telegraphed, telexed or by
facsimile transmission (with receipt confirmed) or mailed by certified mail,
postage prepaid, return receipt requested (such mailed notice to be effective on
the date of such receipt is acknowledged), as follows:

          If to the Company:

                    Regeneron Pharmaceuticals, Inc.
                    777 Old Saw Mill River Road
                    Tarrytown, New York 10591-6707
                    Attn: Corporate Secretary
                    Telecopy No.: (914) 345-7721

          With a copy to:

                    Skadden, Arps, Slate, Meagher & Flom
                    919 Third Avenue
                    New York, New York  10022
                    Attn: Morris J. Kramer, Esq. and Matthew J. Mallow, Esq.
                    Telecopy No.: (212) 735-2000

          If to Buyer:

                    Amgen Inc.
                    Amgen Center
                    1840 DeHavilland Drive
                    Thousand Oaks, California 91320
                    Attn: The Corporate Secretary
                    Telecopy No.: (805) 499-9315

          With a copy to:

                    Latham & Watkins
                    633 West Fifth Street, Suite 4000
                    Los Angeles, California 90071
                    Attn: Michael W. Sturrock, Esq.

                    Telecopy No.: (213) 891-8763

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.


                                          11

<PAGE>

     7.4 CHOICE OF LAW. This Agreement shall be construed, interpreted and the
rights of the parties determined in accordance with the laws of the State of New
York except with respect to matters of law concerning the internal corporate
affairs of any corporate entity which is a party to or the subject of this
Agreement, and as to those matters the law of the jurisdiction under which the
respective entity derives its powers shall govern.

     7.5 ENTIRE AGREEMENT; AMENDMENTS AND WAIVERS. This Agreement, together with
the Collateral Agreements, constitutes the entire agreement among the parties
pertaining to the subject matter hereof and thereof and supersedes all prior
agreements, understandings, negotiations and discussions, whether oral or
written, of the parties. No supplement, modification or waiver of this Agreement
shall be binding unless executed in writing by the party to be bound thereby. No
waiver of any of the provisions of this Agreement shall be deemed or shall
constitute a waiver of any other provision hereof (whether or not similar), nor
shall such waiver constitute a continuing waiver unless otherwise expressly
provided.

     7.6 COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

     7.7 INVALIDITY. In the event that any one or more of the provisions
contained in this Agreement or in any other instrument referred to herein,
shall, for any reason, be held to be invalid, illegal or unenforceable in any
respect, such invalidity, illegality or unenforceability shall not affect any
other provision of this Agreement or any other such instrument.

     7.8 HEADINGS. The headings of the Articles and Sections herein are inserted
for convenience of reference only and are not intended to be a part of or to
affect the meaning or interpretation of this Agreement.

     7.9 EXPENSES. Each of the Company and Buyer will each be liable for its own
costs and expenses incurred in connection with the negotiation, preparation,
execution and performance of this Agreement, provided that the Company will pay
all stamp or similar taxes which may be payable (i) in connection with the
execution and delivery of this Agreement and each of the Collateral Agreements
(and any amendments or modifications thereto), and (ii) in respect of the
issuance of the Securities (including the issuance of the Warrant Shares upon
exercise of the Warrants) to Buyer.

     7.10 PUBLICITY. Except for the initial press relating to the execution and
delivery of this Agreement (the form of which has been agreed to by the parties
hereto



                                          12

<PAGE>

and is attached hereto as Exhibit A), neither party shall issue any press
release or make any public statement regarding the transactions contemplated
hereby, without prior consultation with the other party.

     7.11 SPECIFIC ENFORCEMENT. The Company and Buyer acknowledge and agree that
if any of the provisions of this Agreement were not performed in accordance with
their specific terms or were otherwise breached, irreparable damage would occur
and it would be extremely impracticable and difficult to measure damages.
Accordingly, in addition to any other rights and remedies to which the parties
may be entitled by law or equity, the parties shall be entitled to an injunction
or injunctions to prevent or cure breached of the provisions of this Agreement
and to enforce specifically the terms and provisions hereof, and the parties
expressly waive (i) the defense that a remedy in damages will be adequate and
(ii) any requirement, in an action for specific performance, for the posting of
a bond.

     7.12 FURTHER ASSURANCES. On and after the date hereof, the Company and
Buyer will take all appropriate action and execute all documents, instruments or
conveyances of any kind which may be reasonably necessary or advisable to carry
out any of the provisions hereof.

     7.13 SECTION 912 OF THE NEW YORK BUSINESS CORPORATION LAW. (a) It is the
intent of the parties that neither the approval by the Board of Directors of the
Company of the transactions contemplated by this Agreement and the Collateral
Agreements nor any other action taken or omitted to be taken by the Board of
Directors of the Company in connection with the transactions contemplated by the
foregoing agreements shall be deemed to be approval of Buyer becoming an
"interested shareholder" by the Board of Directors of the Company under Section
912 of the New York Business Corporation Law.

     (b) Buyer hereby represents and warrants to the Company as of the date
hereof that other than the Shares, Warrants and Warrant Shares to be acquired
under this Agreement and the Warrant Agreement, Buyer beneficially owns and has
the right to acquire (whether such right is exercisable immediately or only
after the passage of time) pursuant to any agreement, arrangement or
understanding (whether or not in writing) or upon the exercise of conversion
rights, exchange rights, warrants or options, 788,766 shares of Class A Common
Stock and 1,438,766 shares of Common Stock (which includes 788,766 shares of
Common Stock issuable if and when the shares of Class A Common Stock are
converted into shares of Common Stock).

                           [Signature Page to follow]


                                          13

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement, or
have caused this Agreement to be duly executed on their respective behalf by
their respective officers thereunto duly authorized, as of the day and year

first above written.


                                        AMGEN INC.


                                        By
                                           -----------------------
                                        Name:
                                        Title:


                                        REGENERON PHARMACEUTICALS, INC.


                                        By
                                           -----------------------
                                        Name:
                                        Title:


                                       S-1





<PAGE>
================================================================================



                                  WARRANT AGREEMENT



                                    BY AND BETWEEN

                           REGENERON PHARMACEUTICALS, INC.

                                         and

                                      AMGEN INC.



                              Dated as of April 15, 1996





================================================================================

<PAGE>

                                  TABLE OF CONTENTS


                                                                            PAGE


SECTION 1.    Warrant Certificates..........................................  1

SECTION 2.    Execution of Warrant Certificates.............................  1

SECTION 3.    Registration..................................................  1

SECTION 4.    Registration of Transfers and Exchanges.......................  1

SECTION 5.    Warrants; Exercise of Warrant.................................  2

SECTION 6.    Payment of Taxes..............................................  3

SECTION 7.    Mutilated or Missing Warrant Certificates.....................  3

SECTION 8.    Reservation of Warrant Shares.................................  4

SECTION 9.    Obtaining Stock Exchange Listings.............................  4

SECTION 10.   Adjustment of Exercise Price and Number of Warrant Shares
               Issuable.....................................................  4


    (a)  Adjustment for Change in Capital Stock.............................  5
    (b)  Adjustment for Rights Issue........................................  6
    (c)  Adjustment for Other Distributions.................................  7
    (d)  Adjustment for Common Stock Issue..................................  7
    (e)  Adjustment for Convertible Securities Issue........................  9
    (f)  Current Market Price............................................... 10
    (g)  Consideration Received............................................. 10
    (h)  When De Minimis Adjustment May Be Deferred......................... 11
    (i)  When No Adjustment Required........................................ 11
    (j)  Notice of Adjustment............................................... 11
    (k)  Voluntary Reduction................................................ 11
    (l)  Reorganization of Company.......................................... 12
    (m)  Company Determination Final........................................ 13
    (n)  When Issuance or Payment May Be Deferred........................... 13
    (o)  Adjustment in Number of Shares..................................... 13
    (p)  Form of Warrants................................................... 14

SECTION 11.   Fractional Interests.......................................... 14

SECTION 12.   Notices to Warrant
 holders.................................... 14


                                          i


<PAGE>

SECTION 13.   Notices to Company and Warrant Holder......................... 15

SECTION 14.   Supplements and Amendments.................................... 16

SECTION 15.   Successors.................................................... 16

SECTION 16.   Termination................................................... 17

SECTION 17.   Governing Law................................................. 17

SECTION 18.   Benefits of This Agreement.................................... 17

SECTION 19.   Counterparts.................................................. 17

EXHIBIT A..................................................................  A-1


                                          ii


<PAGE>

     THIS WARRANT AGREEMENT (the "AGREEMENT") is dated as of April 15, 1996 and
entered into by and between REGENERON PHARMACEUTICALS, INC., a New York
corporation (the "COMPANY"), and AMGEN INC., a Delaware corporation ("AMGEN").

     WHEREAS, the Company proposes to issue to Amgen, or its designee, Common
Stock Purchase Warrants, as hereinafter described (the "WARRANTS"), to purchase

up to an aggregate of 700,000 shares of Common Stock, $.001 par value (the
"COMMON STOCK"), of the Company (the Common Stock issuable on exercise of the
Warrants being referred to herein as the "WARRANT SHARES"), pursuant to a Stock
and Warrant Purchase Agreement dated as of the date hereof (the "PURCHASE
AGREEMENT").

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereto agree as follows:

     SECTION 1. WARRANT CERTIFICATES. The certificates evidencing the Warrants
(the "WARRANT CERTIFICATES") to be delivered pursuant to this Agreement shall be
in registered form only and shall be substantially in the form set forth in
EXHIBIT A attached hereto.

     SECTION 2. EXECUTION OF WARRANT CERTIFICATES. Warrant Certificates shall be
signed on behalf of the Company by its Chairman of the Board or its President or
a Vice President and by its Secretary or an Assistant Secretary under its
corporate seal. Each such signature upon the Warrant Certificates may be in the
form of a facsimile signature of the present or any future Chairman of the
Board, President, Vice President, Secretary or Assistant Secretary and may be
imprinted or otherwise reproduced on the Warrant Certificates and for that
purpose the Company may adopt and use the facsimile signature of any person who
shall have been Chairman of the Board, President, Vice President, Secretary or
Assistant Secretary, notwithstanding the fact that at the time the Warrant
Certificates shall be delivered or disposed of he shall have ceased to hold such
office. The seal of the Company may be in the form of a facsimile thereof and
may be impressed, affixed, imprinted or otherwise reproduced on the Warrant
Certificates.

     In case any officer of the Company who shall have signed any of the Warrant
Certificates shall cease to be such officer before the Warrant Certificates so
signed shall have been disposed of by the Company, such Warrant Certificates
nevertheless may be delivered or disposed of as though such person had not
ceased to be such officer of the Company; and any Warrant Certificate may be
signed on behalf of the Company by any person who, at the actual date of the
execution of such Warrant Certificate, shall be a proper officer of the Company
to sign such Warrant Certificate, although at the date of the execution of this
Warrant Agreement any such person was not such officer.

     SECTION 3. REGISTRATION. The Company shall number and register the Warrant
Certificates in a register as they are issued.

     SECTION 4. REGISTRATION OF TRANSFERS AND EXCHANGES. The Company shall from
time to time register the transfer of any outstanding Warrant Certificates in a
Warrant register to be maintained by the Company upon surrender of such Warrant
Certificates accompanied by


                                          1


<PAGE>

a written instrument or instruments of transfer in form satisfactory to the
Company, duly executed by the registered holder or holders thereof or by the

duly appointed legal representative thereof or by a duly authorized attorney.
Upon any such registration of transfer, a new Warrant Certificate shall be
issued to the transferee(s) and the surrendered Warrant Certificate shall be
cancelled and disposed of by the Company.

     The Warrant holders agree that each certificate representing Warrant Shares
will bear the following legend:

     "THIS WARRANT AND THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
     REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE
     OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND
     UNTIL, IN THE CASE OF THE SHARES, SUCH SHARES ARE REGISTERED UNDER SUCH ACT
     OR, IN THE CASE OF THIS WARRANT AND THE SHARES, AN OPINION OF COUNSEL
     REASONABLY SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH
     REGISTRATION IS NOT REQUIRED."

     The Warrant holders further agree that they shall not offer, sell or
otherwise transfer the Warrants or Warrant Shares in violation of the foregoing
legend.

     Warrant Certificates may be exchanged at the option of the holder(s)
thereof, when surrendered to the Company at its office for another Warrant
Certificate or other Warrant Certificates of like tenor and representing in the
aggregate a like number of Warrants. Warrant Certificates surrendered for
exchange shall be cancelled and disposed of by the Company.

     SECTION 5. WARRANTS; EXERCISE OF WARRANTS. Subject to the terms of this
Agreement, each holder of Warrants shall have the right, which may be exercised
commencing at the opening of business on April 16, 1996 and until 5:00 p.m., New
York time on April 15, 2001, to receive from the Company the number of fully
paid and nonassessable Warrant Shares which the holder may at the time be
entitled to receive on exercise of such Warrants and payment to the Company of
the Exercise Price (as defined below) then in effect for such Warrant Shares.
Each Warrant not exercised prior to 5:00 p.m., New York time, on April 15, 2001
shall become void and all rights thereunder and all rights in respect thereof
under this Agreement shall cease as of such time.

     A Warrant may be exercised upon surrender to the Company at its office
designated for such purpose (the address of which is set forth in SECTION 13
hereof) of the certificate or certificates evidencing the Warrants to be
exercised with the form of election to purchase duly filled in and signed, which
signature shall be guaranteed by a bank or trust company having an office or
correspondent in the United States or a broker or dealer which is a member of a
registered securities exchange or the National Association of Securities
Dealers, Inc., and upon payment to the Company of the exercise price (the
"EXERCISE PRICE") which is set forth in the form of Warrant Certificate attached
hereto as EXHIBIT A, subject to adjustment pursuant to SECTION 10, for the
number of Warrant Shares in respect of which such Warrants are


                                        2


<PAGE>


then exercised.  Payment of the aggregate Exercise Price shall be made in cash
or by certified or official bank check payable to the order of the Company.

     Subject to the provisions of SECTION 6 hereof, upon such surrender of
Warrants and payment of the Exercise Price the Company shall issue and cause to
be delivered with all reasonable dispatch to or upon the written order of the
holder and in such name or names as the Warrant holder may designate, a
certificate or certificates for the number of full Warrant Shares issuable upon
the exercise of such Warrants together with cash as provided in SECTION 11;
PROVIDED, HOWEVER, that if any reclassification, consolidation, merger or lease
or sale of assets is proposed to be effected by the Company as described in
subsection (l) of SECTION 10 hereof, or a tender offer or an exchange offer for
shares of Common Stock of the Company shall be made, upon such surrender of
Warrants and payment of the Exercise Price as aforesaid, the Company shall, as
soon as possible, but in any event not later than two business days thereafter,
issue and cause to be delivered the full number of Warrant Shares issuable upon
the exercise of such Warrants in the manner described in this sentence together
with cash as provided in SECTION 11. Such certificate or certificates shall be
deemed to have been issued and any person so designated to be named therein
shall be deemed to have become a holder of record of such Warrant Shares as of
the date of the surrender of such Warrants and payment of the Exercise Price.

     The Warrants shall be exercisable, at the election of the holders thereof,
either in full or from time to time in part and, in the event that a certificate
evidencing Warrants is exercised in respect of fewer than all of the Warrant
Shares issuable on such exercise at any time prior to the date of expiration of
the Warrants, a new certificate evidencing the remaining Warrant or Warrants
will be issued and delivered pursuant to the provisions of this Section and of
SECTION 2 hereof.

     All Warrant Certificates surrendered upon exercise of Warrants shall be
cancelled and disposed of by the Company. The Company shall keep copies of this
Agreement and any notices given or received hereunder available for inspection
by the holders during normal business hours at its office.

     SECTION 6. PAYMENT OF TAXES. The Company will pay all documentary stamp
taxes, if any, attributable to the initial issuance of Warrant Shares upon the
exercise of Warrants.

     SECTION 7. MUTILATED OR MISSING WARRANT CERTIFICATES. In case any of the
Warrant Certificates shall be mutilated, lost, stolen or destroyed, the Company
may in its discretion issue, in exchange and substitution for and upon
cancellation of the mutilated Warrant Certificate, or in lieu of and
substitution for the Warrant Certificate lost, stolen or destroyed, a new
Warrant Certificate of like tenor and representing an equivalent number of
Warrants, but only upon receipt of evidence reasonably satisfactory to the
Company of such loss, theft or destruction of such Warrant Certificate and
indemnity, if requested, also reasonably satisfactory to it. Applicants for such
substitute Warrant Certificates shall also comply with such other reasonable
regulations and pay such other reasonable charges as the Company may prescribe.


                                        3



<PAGE>

     SECTION 8. RESERVATION OF WARRANT SHARES. The Company will at all times
reserve and keep available, free from preemptive rights, out of the aggregate of
its authorized but unissued Common Stock or its authorized and issued Common
Stock held in its treasury, for the purpose of enabling it to satisfy any
obligation to issue Warrant Shares upon exercise of the Warrants, the maximum
number of shares of Common Stock which may then be deliverable upon the exercise
of all the outstanding Warrants.

     The Company or, if appointed, the transfer agent for the Common Stock (the
"TRANSFER AGENT") and every subsequent transfer agent for any shares of the
Company's capital stock issuable upon the exercise of any of the rights of
purchase aforesaid will be irrevocably authorized and directed at all times to
reserve such number of authorized shares as shall be required for such purpose.
The Company will keep a copy of this Agreement on file with the Transfer Agent
and with every subsequent transfer agent for any shares of the Company's capital
stock issuable upon the exercise of the rights of purchase represented by the
Warrants. The Company will furnish such Transfer Agent a copy of all notices of
adjustments and certificates related thereto, transmitted to each holder
pursuant to SECTION 12 hereof.

     Before taking any action which would cause an adjustment pursuant to
SECTION 10 hereof to reduce the Exercise Price below the then par value (if any)
of the Warrant Shares, the Company will take any corporate action which may, in
the opinion of its counsel, be necessary in order that the Company may validly
and legally issue fully paid and nonassessable Warrant Shares at the Exercise
Price as so adjusted.

     The Company covenants that all Warrant Shares which may be issued upon
exercise of Warrants will, upon issue, be fully paid, nonassessable, free of
preemptive rights and free from all documentary stamp taxes, liens, charges and
security interests with respect to the issue thereof.

     SECTION 9. OBTAINING STOCK EXCHANGE LISTINGS. The Company will from time to
time take all action which may be necessary so that the Warrant Shares,
immediately upon their issuance upon the exercise of Warrants, will be listed on
the principal securities exchanges and markets within the United States of
America, if any, on which other shares of Common Stock are then listed.

     SECTION 10. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES
ISSUABLE. The Exercise Price and the number of Warrant Shares issuable upon the
exercise of each Warrant are subject to adjustment from time to time upon the
occurrence of the events enumerated in this SECTION 10. For purposes of this
SECTION 10, "COMMON STOCK" means shares now or hereafter authorized of any class
of common stock of the Company and any other stock of the Company, however
designated, that has the right (subject to any prior rights of any class or
series of preferred stock) to participate in any distribution of the assets or
earnings of the Company without limit as to per share amount, including, without
limitation, the Class A Common Stock, par value $.001, of the Company.


                                        4



<PAGE>

          ADJUSTMENT FOR CHANGE IN CAPITAL STOCK.

          If the Company:

          1. pays a dividend or makes a distribution on its Common Stock in
     shares of its Common Stock;

          2. subdivides its outstanding shares of Common Stock into a greater
     number of shares; or

          3. combines its outstanding shares of Common Stock into a smaller
     number of shares;

then the Exercise Price in effect immediately prior to such action shall then be
adjusted in accordance with the formula:

                        1      O
                       E = E x -
                               A

Where:
      1
     E =  the adjusted Exercise Price

     E =  the current Exercise Price

     O =  the number of shares of Common Stock outstanding prior to such action

     A =  the number of shares of Common Stock outstanding immediately after 
          such action

     In the case of a dividend or distribution the adjustment shall become
effective immediately after the record date for determination of holders of
shares of Common Stock entitled to receive such dividend or distribution, and in
the case of a subdivision or combination, the adjustment shall become effective
immediately after the effective date of such corporate action.

     If after an adjustment a holder of a Warrant upon exercise of it may
receive shares of two or more classes of capital stock of the Company, the
Company shall determine the allocation of the adjusted Exercise Price between
the classes of capital stock. After such allocation, the exercise privilege, the
number of shares issuable upon such exercise, and the Exercise Price of each
class of capital stock shall thereafter be subject to adjustment on terms
comparable to those applicable to Common Stock in this Section 10.


                                        5


<PAGE>

     Such adjustment shall be made successively whenever any event listed above
shall occur.


     (b) ADJUSTMENT FOR RIGHTS ISSUE.

     If the Company distributes any rights, options or warrants to all holders
of its Common Stock entitling them at any time after the record date mentioned
below to purchase shares of Common Stock at a price per share less than the
Current Market Price (as defined in SECTION 10(f)) per share of Common Stock on
that record date, the Exercise Price shall be adjusted in accordance with the
formula:

                                N x P
                            O + -----
                        1         M
                       E  = E x -----
                                O + N


where:
       1
     E  = the adjusted Exercise Price.

     E  = the current Exercise Price.

     O  = the number of shares of Common Stock outstanding on the record date.

     N  = the number of additional shares of Common Stock issuable upon exercise
          of the rights, options or warrants offered.

     P  = the exercise price per share of the additional shares issuable upon 
          exercise of the rights, options or warrants.

     M  = the Current Market Price per share of Common Stock on the record date.

     The adjustment shall be made successively whenever any such rights, options
or warrants are issued and shall become effective immediately after the record
date for the determination of stockholders entitled to receive the rights,
options or warrants. If at the end of the period during which such rights,
options or warrants are exercisable, not all rights, options or warrants shall
have been exercised, the Exercise Price shall be immediately readjusted to what
it would have been if "N" in the above formula had been the number of shares
actually issued.


                                        6


<PAGE>

     (c) ADJUSTMENT FOR OTHER DISTRIBUTIONS.

     If the Company distributes to all holders of its Common Stock any of its
assets (including but not limited to securities and cash), debt securities,
capital stock, or any rights or warrants to purchase assets, debt securities,
capital stock, or other securities of the Company, the Exercise Price shall be
adjusted in accordance with the formula:


                         1       M - F
                        E  = E x -----
                                   M

where:
       1
     E  = the adjusted Exercise Price.

     E  = the current Exercise Price.

     M  = the Current Market Price per share of Common Stock on the record date 
          mentioned below.

     F  = the fair market value on the record date of the assets, debt 
          securities, capital stock or rights or warrants applicable to one 
          share of Common Stock.  The Board of Directors shall determine the
          fair market value.

     The adjustment shall be made successively whenever any such distribution is
made and shall become effective immediately after the record date for the
determination of stockholders entitled to receive the distribution.

     This subsection does not apply to (i) dividends, distributions,
combinations or issuances referred to in subsection (a) of this SECTION 10, (ii)
rights, options or warrants referred to in subsection (b) of this SECTION 10, or
(iii) non-extraordinary quarterly cash dividends distributed to all holders of
Common Stock.

     (d) ADJUSTMENT FOR COMMON STOCK ISSUE.

     If the Company issues shares of Common Stock for a consideration per share
less than the Current Market Price per share of Common Stock on the date the
Company fixes the offering price of such additional shares, the Exercise Price
shall be adjusted in accordance with the formula:


                                        7


<PAGE>

                                       P
                                  O + ---
                          1            M
                         E  = E x -------
                                     A

where:

       1
     E  = the adjusted Exercise Price.

     E  = the then current Exercise Price.


     O  = the number of shares outstanding immediately prior to the issuance of 
          such additional shares.

     P  = the aggregate consideration received for the issuance of such 
          additional shares.

     M  = the Current Market Price per share of Common Stock on the date of
          issuance of such additional shares.

     A  = the number of shares outstanding immediately after the issuance of 
          such additional shares.

     The adjustment shall be made successively whenever any such issuance is
made, and shall become effective immediately after such issuance.

     This subsection (d) does not apply to:

          (1) the exercise of Warrants,

          (2) rights, options, warrants or other distributions referred to in
     subsections (b), (c) or (e) of this SECTION 10,

          (3) Common Stock issued to the Company's directors, employees and
     non-employee service providers under bona fide benefit plans adopted by the
     Board of Directors and approved by the holders of Common Stock when
     required by law, if such Common Stock would otherwise be covered by this
     subsection (d), or

          (4) Common Stock issued in a bona fide public offering pursuant to a
     firm commitment underwriting.

          (5) issuances of shares of Common Stock for a consideration per share
     less than 100%, but greater than 92%, of the Current Market Price per share
     of Common Stock on the date the Company fixes the offering price of such
     additional shares.


                                        8


<PAGE>

     (e) ADJUSTMENT FOR CONVERTIBLE SECURITIES ISSUE.

     If the Company issues any securities convertible into or exchangeable for
Common Stock (other than securities issued in transactions described in
subsections (b) and (c) of this SECTION 10) for a consideration per share of
Common Stock initially deliverable upon conversion or exchange of such
securities less than the Current Market Price per share of Common Stock on the
date of issuance of such securities, the Exercise Price shall be adjusted in
accordance with this formula:

                                        P
                                  O + -----
                          1             M

                         E  = E x ---------
                                    O + D


where:
       1
     E  = the adjusted Exercise Price.

     E  = the then current Exercise Price.

     O  = the number of shares outstanding immediately prior to the issuance of 
          such securities.

     P  = the aggregate consideration received for the issuance of such
          securities.

     M  = the Current Market Price per share of Common Stock on the date of
          issuance of such securities.

     D  = the maximum number of shares deliverable upon conversion or in 
          exchange for such securities at the initial conversion or exchange 
          rate.

     The adjustment shall be made successively whenever any such issuance is
made, and shall become effective immediately after such issuance.

     If all of the Common Stock deliverable upon conversion or exchange of such
securities have not been issued when such securities are no longer outstanding,
then the Exercise Price shall promptly be readjusted to the Exercise Price which
would then be in effect had the adjustment upon the issuance of such securities
been made on the basis of the actual number of shares of Common Stock issued
upon conversion or exchange of such securities.


                                        9


<PAGE>

     This subsection (e) does not apply to convertible securities issued in a
bona fide public offering pursuant to a firm commitment underwriting, nor does
this subsection apply to issuances of any securities convertible into or
exchangeable for Common Stock for a consideration per share of Common Stock
initially deliverable upon conversion or exchange of such securities less than
100%, but greater than 92%, of the Current Market Price per share of Common
Stock on the date of issuance of such securities.

     (f) CURRENT MARKET PRICE.

     As used in this Agreement, the "Current Market Price" per share of Common
Stock on any date is the average of the Quoted Prices of the Common Stock for 30
consecutive trading days commencing 45 trading days before the date in question.
The "Quoted Price" of the Common Stock is the last reported sales price of the
Common Stock as reported by Nasdaq National Market, or if the Common Stock is
listed on a national securities exchange, the last reported sales price of the

Common Stock on such exchange (which shall be for consolidated trading if
applicable to such exchange), or if neither so reported or listed, the last
reported bid price of the Common Stock. In the absence of one or more such
quotations, the Board of Directors of the Company shall determine the Current
Market Price on the basis of such quotations as it in good faith considers
appropriate.

     (g) CONSIDERATION RECEIVED.

     For purposes of any computation respecting consideration received pursuant
to subsections (d) and (e) of this SECTION 10, the following shall apply:

          (1) in the case of the issuance of shares of Common Stock for cash,
     the consideration shall be the amount of such cash, provided that in no
     case shall any deduction be made for any commissions, discounts or other
     expenses incurred by the Company for any underwriting of the issue or
     otherwise in connection therewith;

          (2) in the case of the issuance of shares of Common Stock for a
     consideration in whole or in part other than cash, the consideration other
     than cash shall be deemed to be the fair market value thereof as determined
     in good faith by the Board of Directors (irrespective of the accounting
     treatment thereof), whose determination shall be conclusive, and described
     in a Board resolution; and

          (3) in the case of the issuance of securities convertible into or
     exchangeable for shares, the aggregate consideration received therefor
     shall be deemed to be the consideration received by the Company for the
     issuance of such securities plus the additional minimum consideration, if
     any, to be received by the Company upon the conversion or exchange thereof
     (the consideration in each case to be determined in the same manner as
     provided in clauses (1) and (2) of this subsection).


                                       10


<PAGE>

     (h) WHEN DE MINIMIS ADJUSTMENT MAY BE DEFERRED.

     No adjustment in the Exercise Price need be made unless the adjustment
would require an increase or decrease of at least 1% in the Exercise Price. Any
adjustments that are not made shall be carried forward and taken into account in
any subsequent adjustment.

     All calculations under this Section shall be made to the nearest cent or to
the nearest 1/100th of a share, as the case may be.

     (i) WHEN NO ADJUSTMENT REQUIRED.

     No adjustment need be made for a transaction referred to in subsections
(a), (b), (c), (d) or (e) of this SECTION 10 if Warrant holders are to
participate in the transaction on a basis and with notice that the Board of
Directors determines to be fair and appropriate in light of the basis and notice

on which holders of Common Stock participate in the transaction.

     No adjustment need be made for rights to purchase Common Stock pursuant to
a Company plan for reinvestment of dividends or interest.

     No adjustment need be made for a change in the par value or no par value of
the Common Stock.

     If the Company distributes or issues rights to all holders of its Common
Stock pursuant to a shareholder rights plan, then no adjustment shall be made
pursuant to this SECTION 10 upon such distribution or issuance if, upon exercise
of the Warrants, each holder thereof receives the same type and number of
unexpired rights it would have received (as adjusted for any event described in
SECTION 10(a) OR 10(l)) had it exercised its Warrants, and been a holder of the
Warrant Shares issuable upon exercise thereof, prior to the record date for such
distribution or issuance.

     To the extent Warrants become convertible into cash, no adjustment need be
made thereafter as to the cash. Interest will not accrue on the cash.

     (j) NOTICE OF ADJUSTMENT.

     Whenever the Exercise Price is adjusted, the Company shall provide the
notices required by SECTION 12 hereof.

     (k) VOLUNTARY REDUCTION.

     The Company from time to time may reduce the Exercise Price by any amount
for any period of time if the period is at least 20 days and if the reduction is
irrevocable during the period; PROVIDED, HOWEVER, that in no event may the
Exercise Price be less than the par value of a share of Common Stock.


                                       11


<PAGE>

     Whenever the Exercise Price is reduced pursuant to SUBSECTION 10(k), the
Company shall mail to Warrant holders a notice of the reduction. The Company
shall mail the notice at least 15 days before the date the reduced Exercise
Price takes effect. The notice shall state the reduced Exercise Price and the
period it will be in effect.

     A reduction of the Exercise Price does not change or adjust the Exercise
Price otherwise in effect for purposes of subsections (a), (b), (c), (d) and (e)
of this SECTION 10.

     (l) REORGANIZATION OF COMPANY.

     If any reclassification of the Common Stock of the Company or any
consolidation or merger of the Company with another entity, or the sale or lease
of all or substantially all of the Company's assets to another entity shall be
effected in such a way that holders of the Common Stock of the Company shall be
entitled to receive stock, securities or assets with respect to or in exchange

for such Common Stock, then, as a condition precedent to such reclassification,
consolidation, merger, sale or lease, lawful and adequate provisions shall be
made whereby the Warrant holder shall thereafter have the right to purchase and
receive upon the basis and the terms and conditions specified in this Agreement
and in lieu of the shares of Common Stock immediately theretofore purchasable
and receivable upon the exercise of the rights represented hereby, such shares
of stock, securities or assets as may be issued or payable in such
reclassification, consolidation, merger, sale or lease with respect to or in
exchange for the number of shares of Common Stock purchasable and receivable
upon the exercise of the rights represented hereby had such rights been
exercised immediately prior thereto, and in any such case appropriate provision
shall be made with respect to the rights and interests of the holders of the
Warrants to the end that the provisions hereof (including without limitation
provisions for adjustments of the Exercise Price and of the number of shares of
Common Stock purchasable and receivable upon the exercise of the Warrant) shall
thereafter be applicable, as nearly as may be, in relation to any shares of
stock, securities or assets thereafter deliverable upon the exercise hereof. The
Company will not effect any such reclassification, consolidation, merger, sale
or lease, unless prior to the consummation thereof the successor corporation (if
other than the Company) resulting from such reclassification, consolidation or
merger or the corporation purchasing or leasing such assets shall assume by a
supplemental Warrant Agreement, executed and mailed or delivered to the holders
of the Warrants at the last address thereof appearing on the books of Company,
the obligation to deliver to such holders such shares of stock, securities or
assets as, in accordance with the foregoing provisions, such holders may be
entitled to purchase.

     If the issuer of securities deliverable upon exercise of Warrants under the
supplemental Warrant Agreement is an affiliate of the formed, surviving,
transferee or lessee corporation, that issuer shall join in the supplemental
Warrant Agreement.

     If this subsection (l) applies, subsections (a), (b), (c), (d) and (e) of
this SECTION 10 do not apply.


                                       12


<PAGE>

     (m) COMPANY DETERMINATION FINAL.

     Any determination that the Company or the Board of Directors must make
pursuant to this SECTION 10 is conclusive.

     (n) WHEN ISSUANCE OR PAYMENT MAY BE DEFERRED.

     In any case in which this SECTION 10 shall require that an adjustment in
the Exercise Price be made effective as of a record date for a specified event,
the Company may elect to defer until the occurrence of such event (i) issuing to
the holder of any Warrant exercised after such record date the Warrant Shares
and other capital stock of the Company, if any, issuable upon such exercise over
and above the Warrant Shares and other capital stock of the Company, if any,
issuable upon such exercise on the basis of the Exercise Price and (ii) paying

to such holder any amount in cash in lieu of a fractional share pursuant to
SECTION 11; PROVIDED, HOWEVER, that the Company shall deliver to such holder a
due bill or other appropriate instrument evidencing such holder's right to
receive such additional Warrant Shares, other capital stock and cash upon the
occurrence of the event requiring such adjustment.

     (o) ADJUSTMENT IN NUMBER OF SHARES.

     Upon each adjustment of the Exercise Price pursuant to this SECTION 10,
each Warrant outstanding prior to the making of the adjustment in the Exercise
Price shall thereafter evidence the right to receive upon payment of the
adjusted Exercise Price that number of shares of Common Stock (calculated to the
nearest hundredth) obtained from the following formula:

                                1        E
                               N  = N x ----
                                          1
                                         E

where:
      1
     N = the adjusted number of Warrant Shares issuable upon exercise of a
         Warrant by payment of the adjusted Exercise Price.

     N = the number of Warrant Shares previously issuable upon exercise of a 
         Warrant by payment of the Exercise Price prior to adjustment.
      1
     E = the adjusted Exercise Price.

     E = the Exercise Price prior to adjustment.


                                       13


<PAGE>

     (p) FORM OF WARRANTS.

     Irrespective of any adjustments in the Exercise Price or the number or kind
of shares purchasable upon the exercise of the Warrants, Warrants theretofore or
thereafter issued may continue to express the same price and number and kind of
shares as are stated in the Warrants initially issuable pursuant to this
Agreement.

     SECTION 11. FRACTIONAL INTERESTS. The Company shall not be required to
issue fractional Warrant Shares on the exercise of Warrants. If more than one
Warrant shall be presented for exercise in full at the same time by the same
holder, the number of full Warrant Shares which shall be issuable upon the
exercise thereof shall be computed on the basis of the aggregate number of
Warrant Shares purchasable on exercise of the Warrants so presented. If any
fraction of a Warrant Share would, except for the provisions of this SECTION 11,
be issuable on the exercise of any Warrants (or specified portion thereof), the
Company shall pay an amount in cash equal to the Current Market Price on the day
immediately preceding the date the Warrant is presented for exercise, multiplied

by such fraction.

     SECTION 12. NOTICES TO WARRANT HOLDERS. Upon any adjustment of the Exercise
Price pursuant to SECTION 10, the Company shall promptly thereafter (i) cause to
be filed with the Company a certificate of a firm of independent public
accountants of recognized standing selected by the Board of Directors of the
Company (who may be the regular auditors of the Company) setting forth the
Exercise Price after such adjustment and setting forth in reasonable detail the
method of calculation and the facts upon which such calculations are based and
setting forth the number of Warrant Shares (or portion thereof) issuable after
such adjustment in the Exercise Price, upon exercise of a Warrant and payment of
the adjusted Exercise Price, which certificate shall be conclusive evidence of
the correctness of the matters set forth therein, and (ii) cause to be given to
each of the registered holders of the Warrant Certificates at his address
appearing on the Warrant register written notice of such adjustments by first-
class mail, postage prepaid. Where appropriate, such notice may be given in
advance and included as a part of the notice required to be mailed under the
other provisions of this SECTION 12.

     In case:

          (a) the Company shall authorize the issuance to all holders of shares
     of Common Stock of rights, options or warrants to subscribe for or purchase
     shares of Common Stock or of any other subscription rights or warrants; or

          (b) the Company shall authorize the distribution to all holders of
     shares of Common Stock of evidences of its indebtedness or assets (other
     than cash dividends or cash distributions payable out of earnings or earned
     surplus or dividends or distributions payable in shares of Common Stock);
     or

          (c) of any consolidation or merger to which the Company is a party and
     for which approval of any shareholders of the Company is required, or of
     the conveyance or transfer of all or substantially all of the properties
     and assets of the Company, or of


                                       14


<PAGE>

     any reclassification or change of Common Stock issuable upon exercise of
     the Warrants (other than a change in par value, or from par value to no par
     value, or from no par value to par value, or as a result of a subdivision
     or combination), or a tender offer or exchange offer for shares of Common
     Stock; or

          (d) of the voluntary or involuntary dissolution, liquidation or
     winding up of the Company; or

          (e) the Company proposes to take any action that would require an
     adjustment in the Exercise Price pursuant to subsections (a), (b), (c), (d)
     or (e) of SECTION 10 and if the Company does not arrange for Warrant
     holders to participate pursuant to subsection (i) of SECTION 10, or if the

     Company takes any action that would require a supplemental Warrant
     Agreement pursuant to subsection (l) of SECTION 10,

then the Company shall cause to be given to each of the registered holders of
the Warrant Certificates at his address appearing on the Warrant register, at
least 20 days (or 10 days in any case specified in clauses (a), (b) or (c)
above) prior to the applicable record date hereinafter specified, or promptly in
the case of events for which there is no record date, by first-class mail,
postage prepaid, a written notice stating (i) the date as of which the holders
of record of shares of Common Stock to be entitled to receive any such rights,
options, warrants or distribution are to be determined, or (ii) the initial
expiration date set forth in any tender offer or exchange offer for shares of
Common Stock, or (iii) the date on which any such consolidation, merger,
conveyance, transfer, dissolution, liquidation or winding up is expected to
become effective or consummated, and the date as of which it is expected that
holders of record of shares of Common Stock shall be entitled to exchange such
shares for securities or other property, if any, deliverable upon such
reclassification, consolidation, merger, conveyance, transfer, dissolution,
liquidation or winding up.  The failure to give the notice required by this
SECTION 12 or any defect therein shall not affect the legality or validity of
any distribution, right, option, warrant, consolidation, merger, conveyance,
transfer, dissolution, liquidation or winding up, or the vote upon any action.

     Nothing contained in this Agreement or in any of the Warrant Certificates
shall be construed as conferring upon the holders thereof the right to vote or
to consent or to receive notice as shareholders in respect of the meetings of
shareholders or the election of Directors of the Company or any other matter, or
any rights whatsoever as shareholders of the Company.

     SECTION 13. NOTICES TO COMPANY AND WARRANT HOLDER. Unless otherwise
provided herein, any notice, request, instruction or other document to be given
hereunder by any party to the others shall be in writing and delivered in person
or by courier, telegraphed, telexed or by facsimile transmission (with receipt
confirmed), or mailed by certified mail, postage prepaid, return receipt
requested (such mailed notice to be effective on the date such receipt is
acknowledged), as follows:


                                       15


<PAGE>

     If to the Company:

             Regeneron Pharmaceuticals, Inc.
             777 Old Saw Mill River Road
             Tarrytown, New York 10591-6707
             Attn: Corporate Secretary
             Telecopy No.: (914) 345-7721

     With a copy to:

             Skadden, Arps, Slate, Meagher & Flom
             919 Third Avenue

             New York, New York 10022
             Attn: Morris Kramer, Esq.
             Telecopy No.: (212) 735-2000

     If to Warrant Holder:

             Amgen Inc.
             Amgen Center
             1840 DeHavilland Drive
             Thousand Oaks, California 91320
             Attn: The Corporate Secretary
             Telecopy No.: (805) 499-9315

     With a copy to:

             Latham & Watkins
             633 West Fifth Street, Suite 4000
             Los Angeles, California 90071
             Attn: Michael W. Sturrock, Esq.
             Telecopy No.: (213) 891-8763

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.

     SECTION 14. SUPPLEMENTS AND AMENDMENTS. The Company may not supplement or
amend this Agreement without the prior written approval of the holders of
Warrant Certificates affected by such supplement or amendment.

     SECTION 15. SUCCESSORS. All the covenants and provisions of this Agreement
by or for the benefit of the Company shall bind and inure to the benefit of its
respective successors and assigns hereunder.


                                       16


<PAGE>

     SECTION 16. TERMINATION. This Agreement shall terminate at 5:00 p.m., New
York time on April 15, 2001. Notwithstanding the foregoing, this Agreement will
terminate on any earlier date if all Warrants have been exercised.

     SECTION 17. GOVERNING LAW. This Agreement and each Warrant Certificate
issued hereunder shall be deemed to be a contract made under the laws of the
State of New York and for all purposes shall be construed in accordance with the
internal laws of said State.

     SECTION 18. BENEFITS OF THIS AGREEMENT. Nothing in this Agreement shall be
construed to give to any person or corporation other than the Company and the
registered holders of the Warrant Certificates any legal or equitable right,
remedy or claim under this Agreement; but this Agreement shall be for the sole
and exclusive benefit of the Company and the registered holders of the Warrant
Certificates.

     SECTION 19. COUNTERPARTS. This Agreement may be executed in any number of

counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument.

                           [Signature Page To Follow]


                                       17


<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, as of the day and year first above written.


                                       REGENERON PHARMACEUTICALS, INC.



                                       By:
                                          -------------------------------------
                                          Name:  Leonard S. Schleifer
                                          Title: President

- -----------------------------------
Seal




Attest:
         --------------------------
              Secretary


                                       AMGEN INC.



                                       By:
                                          -----------------------------------
                                          Name:
                                          Title:

- -----------------------------------
Seal




Attest:
         --------------------------
              Secretary



                                       S-1


<PAGE>

                                                                       EXHIBIT A

                          [Form of Warrant Certificate]

THIS WARRANT AND THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED,
SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL, WITH
RESPECT TO THE SHARES, SUCH SHARES ARE REGISTERED UNDER SUCH ACT OR, WITH
RESPECT TO THIS WARRANT OR THE SHARES, AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH REGISTRATION IS
NOT REQUIRED.

     EXERCISABLE ON OR BEFORE 5:00 P.M., NEW YORK TIME, APRIL 15, 2001

No.                                                             700,000 Warrants

                               Warrant Certificate

                         REGENERON PHARMACEUTICALS, INC.

     This Warrant Certificate certifies that Amgen, Inc., or registered assigns,
is the registered holder of 700,000 Warrants expiring April 15, 2001 (the
"WARRANTS") to purchase Common Stock, $.001 par value (the "COMMON STOCK"), of
REGENERON PHARMACEUTICALS, INC., a New York corporation (the "COMPANY"). Each
Warrant entitles the holder to receive from the Company upon exercise on or
before 5:00 p.m. New York Time on April 15, 2001, one fully paid and
nonassessable share of Common Stock (a "WARRANT SHARE") at the initial exercise
price (the "EXERCISE PRICE") of $16.00 payable in lawful money of the United
States of America upon surrender of this Warrant Certificate and payment of the
Exercise Price at the office of the Company designated for such purpose, subject
to the conditions set forth herein and in the Warrant Agreement referred to
herein. The Exercise Price and number of Warrant Shares issuable upon exercise
of the Warrants are subject to adjustment upon the occurrence of certain events
set forth in the Warrant Agreement.

     No Warrant may be exercised after 5:00 p.m., New York Time on April 15,
2001, and to the extent not exercised by such time such Warrants shall become
void.


                                       A-1


<PAGE>

     The Warrants evidenced by this Warrant Certificate are issued pursuant to a
Warrant Agreement dated as of April 15, 1996 (the "WARRANT AGREEMENT"), duly
executed and delivered by the Company, which Warrant Agreement is hereby
incorporated by reference in and made a part of this instrument and is hereby
referred to for a description of the rights, limitation of rights, obligations,

duties and immunities thereunder of the Company and the holders (the words
"holders" or "holder" meaning the registered holders or registered holder) of
the Warrants. A copy of the Warrant Agreement may be obtained by the holder
hereof upon written request to the Company.

     Warrants may be exercised at any time on or before 5:00 p.m., New York time
on April 15, 2001. The holder of Warrants evidenced by this Warrant Certificate
may exercise them by surrendering this Warrant Certificate, with the form of
election to purchase set forth hereon properly completed and executed, together
with payment of the Exercise Price at the office of the Company designated for
such purpose. In the event that upon any exercise of Warrants evidenced hereby
the number of Warrants exercised shall be less than the total number of Warrants
evidenced hereby, there shall be issued to the holder hereof or his assignee a
new Warrant Certificate evidencing the number of Warrants not exercised. No
adjustment shall be made for any dividends on any Common Stock issuable upon
exercise of this Warrant.

     The Warrant Agreement provides that upon the occurrence of certain events
the Exercise Price set forth on the face hereof may, subject to certain
conditions, be adjusted. If the Exercise Price is adjusted, the Warrant
Agreement provides that the number of shares of Common Stock issuable upon the
exercise of each Warrant shall be adjusted. No fractions of a share of Common
Stock will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement.

     The holders of Warrants are entitled to certain registration rights with
respect to the Common Stock purchasable upon exercise thereof. Said registration
rights are set forth in full in a Registration Rights Agreement dated as of
April 15, 1996, between the Company and Amgen. A copy of the Registration Rights
Agreement may be obtained by the holder hereof upon written request to the
Company.

     Warrant Certificates, when surrendered at the office of the Company by the
registered holder thereof in person or by legal representative or attorney duly
authorized in writing, may be exchanged, in the manner and subject to the
limitations provided in the Warrant Agreement, but without payment of any
service charge, for another Warrant Certificate or Warrant Certificates of like
tenor evidencing in the aggregate a like number of Warrants.

     Upon due presentation for registration of transfer of this Warrant
Certificate at the office of the Company a new Warrant Certificate or Warrant
Certificates of like tenor and evidencing in the aggregate a like number of
Warrants shall be issued to the transferee(s) in exchange for this Warrant
Certificate, subject to the limitations provided in the Warrant Agreement,
without charge except for any tax or other governmental charge imposed in
connection therewith.


                                       A-2


<PAGE>

     The Company may deem and treat the registered holder(s) thereof as the
absolute owner(s) of this Warrant Certificate (notwithstanding any notation of

ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof, of any distribution to the holder(s) hereof, and for all other
purposes, and the Company shall not be affected by any notice to the contrary.
Neither the Warrants nor this Warrant Certificate entitles any holder hereof to
any rights of a stockholder of the Company.

     This Warrant Certificate shall not be valid unless countersigned by the
Company, as such term is used in the Warrant Agreement.

     This Warrant Certificate shall not be offered, sold or otherwise
transferred in violation of the legend on the first page hereof.

                           [Signature Page To Follow]


                                       A-3


<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant Certificate to be
signed by its President and by its Secretary and has caused its corporate seal
to be affixed hereunto or imprinted hereon.

Dated:  April 15, 1996


                                     REGENERON PHARMACEUTICALS, INC.



                                     By:
                                        ---------------------------------------
                                        Name:  Leonard S. Schleifer
                                        Title:  President



                                     By:
                                        ----------------------------------------
                                        Name:  Paul Lubetkin
                                        Title:  Secretary


                                       S-1


<PAGE>

                          [Form of Election to Purchase

                    (To Be Executed Upon Exercise Of Warrant)

     The undersigned hereby irrevocably elects to exercise the right,
represented by this Warrant Certificate, to receive _________ shares of Common
Stock and herewith tenders payment for such shares to the order of REGENERON

PHARMACEUTICALS, INC. in the amount of $_________ in accordance with the terms
hereof. The undersigned requests that a certificate for such shares be
registered in the name of ________________, whose address is
_______________________________ and that such shares be delivered to
________________ whose address is _________________________________. If said
number of shares is less than all of the shares of Common Stock purchasable
hereunder, the undersigned requests that a new Warrant Certificate representing
the remaining balance of such shares be registered in the name of
______________, whose address is _________________________, and that such
Warrant Certificate be delivered to _________________, whose address is
__________________.


                                     Signature:
                                               ---------------------------------


Date:
      ------------------------


                                   Signature Guaranteed:
                                                        ------------------------






<PAGE>
================================================================================





                          REGISTRATION RIGHTS AGREEMENT


                                 BY AND BETWEEN

                         REGENERON PHARMACEUTICALS, INC.

                                       and

                                   AMGEN INC.


                           Dated as of April 15, 1996






================================================================================


<PAGE>

                               TABLE OF CONTENTS*

SECTION 1.  Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . .   1

SECTION 2.  Securities Subject to this Agreement . . . . . . . . . . . . . .   2

     (a)    Registrable Securities . . . . . . . . . . . . . . . . . . . . .   2
     (b)    Holders of Registrable Securities. . . . . . . . . . . . . . . .   2

SECTION 3.  Demand Registrations . . . . . . . . . . . . . . . . . . . . . .   3

     (a)    Demand by Holders. . . . . . . . . . . . . . . . . . . . . . . .   3
     (b)    Effective Registration . . . . . . . . . . . . . . . . . . . . .   3
     (c)    Registration Statement Form. . . . . . . . . . . . . . . . . . .   4
     (d)    Selection of Underwriters. . . . . . . . . . . . . . . . . . . .   4
     (e)    Registration of Other Securities . . . . . . . . . . . . . . . .   4
     (f)    Priority Among Holders of Registrable Securities in Requested
            Registration . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     (g)    Delay of Requested Registration. . . . . . . . . . . . . . . . .   5

SECTION 4.  Piggyback Registrations. . . . . . . . . . . . . . . . . . . . .   5

     (a)    Participation. . . . . . . . . . . . . . . . . . . . . . . . . .   5
     (b)    Underwriter's Cutback. . . . . . . . . . . . . . . . . . . . . .   6

     (c)    No Effect on Demand Registrations. . . . . . . . . . . . . . . .   6

SECTION 5.  Hold-Back Agreements . . . . . . . . . . . . . . . . . . . . . .   7

     (a)    Restrictions Applicable to Company Registration. . . . . . . . .   7
     (b)    Restrictions Applicable to Demand Registration . . . . . . . . .   7

SECTION 6.  Registration Procedures. . . . . . . . . . . . . . . . . . . . .   9

SECTION 7.  Registration Expenses. . . . . . . . . . . . . . . . . . . . . .  14

SECTION 8.  Indemnification. . . . . . . . . . . . . . . . . . . . . . . . .  15

     (a)    Indemnification by Company . . . . . . . . . . . . . . . . . . .  15
     (b)    Indemnification by Holder of Registrable Securities. . . . . . .  16
     (c)    Contribution . . . . . . . . . . . . . . . . . . . . . . . . . .  17

- ----------
*    This Table of Contents does not constitute a part of this Agreement or have
     any bearing upon the interpretation of any of its terms or provisions.


                                        i


<PAGE>


SECTION 9.  Rule 144 . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18

SECTION 10.  Participation in Underwritten Registrations . . . . . . . . . .  18

SECTION 11.  Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . .  18

     (a)    Remedies . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
     (b)    No Inconsistent Agreements . . . . . . . . . . . . . . . . . . .  18
     (c)    Amendments and Waivers . . . . . . . . . . . . . . . . . . . . .  19
     (d)    Notices. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20
     (e)    Successors and Assigns . . . . . . . . . . . . . . . . . . . . .  19
     (f)    Counterparts . . . . . . . . . . . . . . . . . . . . . . . . . .  20
     (g)    Headings . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20
     (h)    Governing Law. . . . . . . . . . . . . . . . . . . . . . . . . .  20
     (i)    Severability . . . . . . . . . . . . . . . . . . . . . . . . . .  20
     (j)    Entire Agreement . . . . . . . . . . . . . . . . . . . . . . . .  20
     (k)    Limitations on Subsequent Registrations. . . . . . . . . . . . .  20


                                       ii


<PAGE>

     THIS REGISTRATION RIGHTS AGREEMENT (the "AGREEMENT") is dated as of April
15, 1996 and entered into by and between REGENERON PHARMACEUTICALS, INC., a New
York corporation (the "COMPANY") and AMGEN INC., a Delaware corporation (the
"PURCHASER").


     This Agreement is made in connection with the execution and delivery of the
Stock and Warrant Purchase Agreement, dated as of the date hereof, between the
Company and the Purchaser (the "PURCHASE AGREEMENT"). In order to induce the
Purchaser to enter into the Purchase Agreement, the Company has agreed to
provide the registration rights set forth in this Agreement.

     The parties hereby agree as follows:

     SECTION 1. DEFINITIONS.

     As used in this Agreement, the following capitalized terms shall have the
following meanings:

     AGENT: Any Person authorized to act and who acts on behalf of the Purchaser
with respect to the transactions contemplated by this Agreement.

     COMMON STOCK: The common stock, $.001 par value, of the Company.

     EXCHANGE ACT: The Securities Exchange Act of 1934, as amended from time to
time.

     NASD: National Association of Securities Dealers, Inc.

     PERSON: An individual, partnership, corporation, limited liability company,
trust or unincorporated organization, or other business entity, or a government
or agency or political subdivision thereof.

     PROSPECTUS: The prospectus included in any Registration Statement, as
amended or supplemented by any prospectus supplement with respect to the terms
of the offering of any portion of the Registrable Securities covered by the
Registration Statement and by all other amendments and supplements to the
prospectus, including post-effective amendments and all material incorporated by
reference in such prospectus.

     REGISTRABLE SECURITIES: (i) the Common Stock acquired by the Purchaser
pursuant to the terms of the Purchase Agreement, and (ii) the Warrant Shares.
Registrable Securities shall also include any securities which may be issued or
distributed with respect to, or in exchange for, such Registrable Securities
pursuant to a stock dividend, stock split or other


                                        1


<PAGE>

distribution, merger, consolidation, recapitalization or reclassification or
similar transaction; PROVIDED, HOWEVER, that any such Registrable Securities
shall cease to be Registrable Securities to the extent (i) a Registration
Statement with respect to the sale of such Registrable Securities has been
declared effective under the Securities Act and such Registrable Securities have
been disposed of in accordance with the plan of distribution set forth in such
Registration Statement, (ii) such Registrable Securities are distributed
pursuant to Rule 144 (or any similar provision then in force) under the
Securities Act, or (iii) such Registrable Securities shall have been otherwise

transferred, new certificates for them not bearing a legend restricting transfer
under the Securities Act shall have been delivered by the Company and they may
be publicly resold without subsequent registration under the Securities Act or
in compliance with Rule 144 thereunder; PROVIDED, FURTHER, HOWEVER, that any
securities that have ceased to be Registrable Securities cannot thereafter
become Registrable Securities.

     REGISTRATION: A registration of the Company's securities for sale to the
public under a Registration Statement.

     REGISTRATION EXPENSES: See SECTION 7 hereof.

     REGISTRATION STATEMENT: Any registration statement of the Company filed
with the Securities and Exchange Commission under the rules and regulations
promulgated under the Securities Act, including the Prospectus, amendments and
supplements to such Registration Statement, including post- effective
amendments, and all exhibits and all material incorporated by reference in such
Registration Statement.

     SECURITIES ACT: The Securities Act of 1933, as amended from time to time.

     SEC: The Securities and Exchange Commission.

     UNDERWRITTEN REGISTRATION or UNDERWRITTEN OFFERING: A Registration in which
securities of the Company are sold to an underwriter for reoffering to the
public.

     WARRANTS: The Warrants, each to purchase shares of Common Stock, issued and
sold pursuant to the Purchase Agreement and the Warrant Agreement dated as of
the date hereof, by and between the Company and the Purchaser (the "WARRANT
AGREEMENT").

     WARRANT SHARES: Any shares of Common Stock issued or issuable upon exercise
of any of the Warrants.

     SECTION 2. SECURITIES SUBJECT TO THIS AGREEMENT.

     (a) REGISTRABLE SECURITIES. The securities entitled to the benefits of this
Agreement are the Registrable Securities.

     (b) HOLDERS OF REGISTRABLE SECURITIES. A Person is deemed to be a holder of
Registrable Securities whenever such Person owns Registrable Securities or has
the right to acquire such Registrable Securities, whether or not such ownership
or right was acquired


                                        2


<PAGE>

pursuant to the Purchase Agreement, or the Warrant Agreement, and whether or not
such acquisition has actually been effected and disregarding any legal
restrictions upon the exercise of such right.


     SECTION 3. DEMAND REGISTRATIONS.

     (a) DEMAND BY HOLDERS. The holders of a majority of Registrable Securities,
at any time from and after the date hereof, may make a total of two written
requests to the Company for Registration of Registrable Securities under and in
accordance with the provisions of the Securities Act of all or part of the
Registrable Securities. Any such Registration requested shall hereinafter be
referred to as a "DEMAND REGISTRATION." Each request for a Demand Registration
shall specify the kind and aggregate amount of Registrable Securities to be
registered and the intended methods of disposition thereof. Upon such request
for a Demand Registration, the Company shall use its best efforts to promptly
effect the Registration of such Registrable Securities under (i) the Securities
Act, and (ii) subject to SECTION 6(h), the blue sky laws of such jurisdictions
as any holder of such Registrable Securities requesting such Registration or any
underwriter, if any, may reasonably request. The Company shall also use its best
efforts to have all such Registrable Securities registered with or approved by
such other federal or state governmental agencies or authorities as may be
necessary in the opinion of counsel to the Company and counsel to the holders of
a majority of such Registrable Securities to consummate the disposition of such
Registrable Securities.

     Notwithstanding the foregoing, the Company shall not be obligated to effect
a Demand Registration if all (but not less than all) of the shares requested to
be registered could immediately be sold by such holders under Rule 144 under the
Securities Act at a price substantially equivalent to the prevailing market
price. The final determination of whether all of the shares could immediately be
sold under Rule 144 shall be made in good faith by counsel for holders of the
Registrable Securities after, among other things, considering the possible
affiliate status of any such holder. The Company shall have the burden of
establishing that the shares could immediately be sold at a price substantially
equivalent to the prevailing market price. In addition, the Company shall not be
required to effect a Demand Registration within six months after the effective
date of any Registration Statement filed at the request of holders of
Registrable Securities pursuant to the terms of this Agreement or the Class D
Convertible Preferred Stock Purchase Agreement dated as of August 31, 1990. Any
request for a Demand Registration not effected pursuant to the provisions of
this paragraph shall not count against the two requests specified in the
preceding paragraph.

     (b) EFFECTIVE REGISTRATION. Subject to the last paragraph of SECTION 6, the
Company shall be deemed to have effected a Demand Registration if the
Registration Statement relating to such Demand Registration is declared
effective by the SEC and remains effective for at least 90 days; PROVIDED,
HOWEVER, that no Demand Registration shall be deemed to have been effected if
(i) such registration, after it has become effective, is interfered with by any
stop order, injunction or other order or requirement of the SEC or other
governmental agency or court for any reason not attributable to the selling
holders of Registrable Securities, or (ii) the conditions to closing specified
in the purchase agreement or underwriting agreement entered into in connection
with such registration are not satisfied, other than by reason of a failure on
the


                                        3



<PAGE>

part of the selling holders of Registrable Securities or any underwriter
referred to in SECTION 3(d).

     (c) REGISTRATION STATEMENT FORM. Registrations under this SECTION 3 shall
be on such appropriate registration form of the SEC as shall permit the
disposition of such Registrable Securities in accordance with the intended
method or methods of disposition specified in such holders' requests for such
Registration. If, in connection with any Registration under this SECTION 3 which
is proposed by the Company to be on Form S-3 or any successor form to such Form,
the managing underwriter (if any) or holders of a majority of the Registrable
Securities requesting a Demand Registration shall advise the Company in writing
that in its opinion additional disclosure not required by such form is of
material importance to the success of the offering, then such Registration shall
include such additional disclosure.

     (d) SELECTION OF UNDERWRITERS. If at any time or from time to time during
the time period applicable to Demand Registrations any of the holders of the
Registrable Securities covered by a Registration Statement desire to sell
Registrable Securities in an Underwritten Offering, the investment banker or
investment bankers that will manage the offering will be selected as follows:

          (1) MANAGING UNDERWRITER. A majority of the holders of Registrable
     Securities shall select three (or, if such holder(s) desires, more than
     three) nationally recognized investment banking firms as candidates for the
     offering, each of which is ready, willing and able to act as the managing
     underwriter, and shall provide a list of such candidates to the Company.
     Not later than five business days following the receipt of such list, the
     Company shall: (i) choose one of three candidates to act as the managing
     underwriter for the offering and (ii) notify the holders of a majority of
     Registrable Securities of such choice.

          (2) CO-MANAGERS. The investment banking firm(s), if any, that will
     serve as co-manager(s) of the offering will be selected by holders of a
     majority of Registrable Securities.

     (e) REGISTRATION OF OTHER SECURITIES. Whenever the Company shall effect a
Registration pursuant to this SECTION 3 in connection with an Underwritten
Offering by one or more holders of Registrable Securities, no securities other
than Registrable Securities shall be included among the securities covered by
such Registration if the managing underwriter of such offering shall have
advised each selling holder of Registrable Securities to be covered by such
Registration in writing (with a copy to the Company) that, in its opinion, the
number of securities requested to be included in such Registration exceeds the
number which can be sold in such offering within a price range acceptable to the
selling holders of a majority of the Registrable Securities requested to be
included in such Registration. If no such notice or letter is provided, the
Company may include shares of Common Stock for its own account or for the
account of other shareholders of the Company having the right to include such
shares in a Registration Statement filed by the Company with the SEC.



                                        4


<PAGE>

     (f) PRIORITY AMONG HOLDERS OF REGISTRABLE SECURITIES IN REQUESTED
REGISTRATION. If the managing underwriter of an Underwritten Offering pursuant
to this SECTION 3 advises each of the holders of Registrable Securities in
writing (with a copy to the Company) that less than all of the Registrable
Securities proposed to be included in such offering should be included (using
the same standard described in subsection (e) hereof), then the amount of
Registrable Securities to be offered for the accounts of holders of Registrable
Securities shall be reduced pro rata, based on the number of Registrable
Securities owned by such holders.

     (g) DELAY OF REQUESTED REGISTRATION. Notwithstanding anything to the
contrary contained in this SECTION 3, if following a request for a Demand
Registration the Company provides prompt written notification to all holders of
Registrable Securities specifying the nature of any Delay Event described below,
then the filing of the Registration Statement pursuant to the request for Demand
Registration may be delayed by the Company for a period not to exceed six months
from the date of its receipt of the written request for the Demand Registration
or such shorter period provided below; provided, however, that such right to
delay a request may be exercised by the Company not more than once in any two
year period. A "Delay Event" shall be defined as any of the following: (1) the
Company will file within 60 days following its receipt of the written request
for Demand Registration, a Registration Statement for the public offering of
securities for the account of the Company; (2) if the Securities Act or the
rules or regulations thereunder, or the form on which the Registration Statement
for the Demand Registration is to be filed, requires the filing of financial
statements which are not yet available (in which case, the Company shall prepare
or cause such statements to be prepared in a reasonably timely and diligent
manner and promptly thereafter file the Registration Statement); (3) at the time
of the request for Demand Registration, the Company is engaged in a material
transaction or has an undisclosed material corporate development, and in either
case, which would be required to be disclosed under the federal securities laws
in the Registration Statement, but the Company's Board of Directors has made a
good faith determination that making such disclosure at such time would
materially adversely affect such transaction or development (in which case, the
Company shall disclose the matter as promptly as practicable and promptly
thereafter file the Registration Statement); or (4) at the time of the request
of the Demand Registration, the Company is engaged in any financing (except the
type described in clause (1) above) (in which case the Company shall file the
Registration Statement no later than 30 days following its receipt of the
written request for Demand Registration).

     SECTION 4. PIGGYBACK REGISTRATIONS.

     (a) PARTICIPATION. Subject to SECTION 4(b) hereof, if at any time from and
after the date hereof, the Company proposes to file a Registration Statement
under the Securities Act with respect to any offering of any of its shares of
Common Stock, whether or not by the Company for its own account (other than (i)
a registration on Form S-4 (or otherwise in connection with non-cash offerings,
exchange offers, mergers or recapitalizations) or S-8 or any successor form to
such Forms, or (ii) any registration of securities as it relates to an offering

and sale to directors or employees of, or non-employee service providers to, the
Company under bona fide benefits plans adopted by the Board of Directors of the
Company and approved by the holders of Common Stock when required by law), then,
as promptly as practicable, the Company shall give written notice of such
proposed filing to each holder of Registrable Securities and such notice shall
offer the holders of Registrable Securities the opportunity to register such
number of Registrable


                                        5


<PAGE>

Securities as each such holder may request (a "PIGGYBACK REGISTRATION").
Subject to SECTION 4(b), the Company shall include in such Registration
Statement all Registrable Securities requested within 15 days after the receipt
of any such notice (which request shall specify the Registrable Securities
intended to be disposed of by such holder) to be included in the Registration
for such offering pursuant to a Piggyback Registration.  Notwithstanding the
foregoing, the Company shall not be obligated to include in a Piggyback
Registration the shares of Registrable Securities requested to be included by a
holder of Registrable Securities if: (i) all (but not less than all) of the
shares requested to be included by that holder could immediately be sold by that
holder under Rule 144 under the Securities Act at a price substantially
equivalent to the prevailing market price and (ii) the Company provides to that
holder a written waiver and consent allowing such holder to sell or otherwise
dispose of all of such shares requested to be included without limitation to the
restrictions imposed by Section 5(a) hereof.  The final determination of whether
all of the shares could immediately be sold under Rule 144 shall be made in good
faith by counsel for such holder after, among other things, considering the
possible affiliate status of such holder.  The Company shall have the burden of
establishing that the shares could immediately be sold at a price substantially
equivalent to the prevailing market price.  Each holder of Registrable
Securities shall be permitted to withdraw all or part of such holder's
Registrable Securities from a Piggyback Registration at any time prior to the
effective date thereof.

     (b) UNDERWRITER'S CUTBACK. The Company shall use its best efforts to cause
the managing underwriter or underwriters of a proposed Underwritten Offering to
permit the Registrable Securities requested to be included in the Registration
for such offering under SECTION 4(a) (the "PIGGYBACK SECURITIES"), to be
included on the same terms and conditions as any similar securities included
therein. Notwithstanding the foregoing, if the managing underwriter of any such
proposed Underwritten Offering informs the Company and the holders of such
Piggyback Securities in writing that, in its opinion, the number of shares of
Common Stock (including the Piggyback Securities) requested to be included in
such Registration exceeds the number which can be sold in such offering within a
price range acceptable to the party who has requested the filing of the
Registration Statement (the Company or other holders of the Company's Common
Stock, as the case may be, hereafter referred to as the "Requesting Party"),
then the shares of Common Stock to be included in such Registration shall be the
number that can be sold within a price range acceptable to the Requesting Party,
selected (i) first, from the shares of Common Stock originally proposed by the
Requesting Party to be included in the Registration for such offering, (ii)

second, and only if all the shares of Common Stock referenced in clause (i) have
been included, from shares of Common Stock subject to piggyback registration
rights originally proposed to be included by all holders of shares of Common
Stock (other than the Requesting Party), selected pro rata based upon the total
ownership of such shares of Common Stock subject to piggyback registration
rights of such holders, and (iii) third, and only if all of the shares of Common
Stock referenced in clause (ii) have been included, from any other securities
eligible for inclusion in such Registration.

     (c) NO EFFECT ON DEMAND REGISTRATIONS. No Registration of Registrable
Securities effected pursuant to a request under this SECTION 4 shall be deemed
to have been effected pursuant to SECTION 3 hereof or shall relieve the Company
of its obligation to effect any Registration upon request under SECTION 3
hereof.


                                        6


<PAGE>

     SECTION 5. HOLD-BACK AGREEMENTS.

     (a)  RESTRICTIONS APPLICABLE TO COMPANY REGISTRATION.

          (1) RESTRICTIONS APPLICABLE TO HOLDERS OF REGISTRABLE SECURITIES. Each
holder of Registrable Securities, if requested by the Company and, in the case
of an Underwritten Offering, the managing underwriters, shall agree not to sell,
transfer or otherwise dispose of any Registrable Securities or other equity
securities (or any securities convertible, exchangeable or exercisable for such
equity securities) of the Company beneficially owned by it (except, in either
case, those that are included in a Piggyback Registration) for a specified
period of time (the "HOLDBACK PERIOD") in the event that the Company notifies
such holder that it desires to file a Registration Statement (the "COMPANY
REGISTRATION STATEMENT") to register the sale of shares of Common Stock (or any
securities convertible, exchangeable or exercisable for such Common Stock)
(other than a Registration referred to in clause (i) or (ii) of Section 4(a)).
The Holdback Period shall commence on the date the Company Registration
Statement is declared effective by the SEC and shall terminate 120 days
thereafter. A written agreement (the "Lock Up") memorializing each such holder's
agreement to the foregoing restrictions shall be executed in a form reasonably
satisfactory to the Company and, if applicable, the managing underwriters.

          (2) RESTRICTIONS APPLICABLE TO OFFICERS, DIRECTORS AND OTHER
STOCKHOLDERS, As a condition to each holder's delivery of the Lock Up pursuant
to SECTION 5(a)(1), the Company shall use its best efforts to obtain from each
of its: (i) officers, (ii) directors and (iii) shareholders beneficially owning
at least as many shares of Common Stock as the aggregate number of shares
beneficially owned by the holders of Registrable Securities, a written agreement
substantially similar to the Lock Up pursuant to which each such Person shall
agree not to sell, transfer or otherwise dispose of any equity securities (or
any securities convertible, exchangeable or exercisable for such equity
securities) of the Company beneficially owned by it under the same terms as the
Lock Up (excluding shares that are included in a Piggyback Registration);
provided however, that each of the officers and directors may sell, transfer or

dispose of during the Holdback Period the amount of equity securities of the
Company that each would be permitted to sell under Rule 144 during a 90 day
period commencing on the effective date of the Company Registration Statement.

     (b) RESTRICTIONS APPLICABLE TO DEMAND REGISTRATION. The following
restrictions on the sale, transfer or other disposition of the Company's equity
securities (or any securities convertible, exchangeable or exercisable for such
equity securities) by the Company, its officers and directors, certain other
shareholders and holders of Registrable Securities shall apply in the event of a
Demand Registration:

          (1) REGISTRATION RESTRICTIONS APPLICABLE TO THE COMPANY. The Company,
if requested by the holders of a majority of Registrable Securities and, in the
case of an Underwritten Offering, the managing underwriters, shall agree not to
effect any public sale or distribution of its equity securities (or any
securities convertible, exchangeable, or exercisable


                                        7


<PAGE>

for such equity securities) (except those that may be included in a Piggyback 
Registration) or any private offer, sale or distribution of its equity 
securities (or any securities convertible, exchangeable or exercisable for 
such equity securities) that may be integrated under the federal securities 
laws or the regulations thereunder with a Demand Registration, for the 
Demand Registration Holdback Period in the event of a Demand Registration.  
The "Demand Registration Holdback Period" shall be defined as the period 
commencing on the date that the Registration Statement for the Demand 
Registration is declared effective by the SEC and shall terminate 120 days 
thereafter.  A written agreement memorializing the Company's agreement to the 
foregoing restrictions shall be executed in a form reasonably satisfactory to 
the holders of a majority of Registrable Securities and, if applicable, the 
managing underwriters.

          (2) RESTRICTIONS APPLICABLE TO OFFICERS AND DIRECTORS. The Company, if
requested by the holders of a majority of Registrable Securities and, in the
case of an Underwritten Offering, the managing underwriters, shall cause Dr.
Leonard Schleifer (so long as he remains the Chief Executive Officer of the
Company), and shall use its best efforts to cause each of its other officers and
directors, to agree not to sell, transfer or otherwise dispose of any equity
securities (or any securities convertible, exchangeable, or exercisable for such
equity securities) of the Company beneficially owned by each such Person (except
those that may be included in a Piggyback Registration) during the Demand
Registration Holdback Period in the event of a Demand Registration; provided,
however, that all such officers and directors in the aggregate may sell,
transfer or otherwise dispose of an aggregate of up to five percent of the total
number of shares included in the Demand Registration. A written agreement
memorializing each such Person's agreement to the foregoing restrictions shall
be executed in a form reasonably satisfactory to the holders of a majority of
Registrable Securities and, if applicable, the managing underwriters.

          (3) RESTRICTIONS APPLICABLE TO OTHER STOCKHOLDERS. The Company, if

requested by the holders of a majority of Registrable Securities and, in the
case of an Underwritten Offering, the managing underwriters, shall cause each
holder of its privately placed equity securities (or any securities convertible,
exchangeable, or exercisable for such equity securities) issued by the Company
at any time on or after the date of this Agreement to agree (for the benefit of
the holders of Registrable Securities) not to effect any public sale or
distribution of any such securities during the Demand Registration Holdback
Period in the event of a Demand Registration. In addition, the Company shall use
its best efforts to cause each such other shareholder of the Company
beneficially owning at least five percent of the Company's then outstanding
equity securities (OR any securities convertible, exchangeable, or exercisable
for such equity securities) to agree not to effect any public sale or
distribution of equity securities (or any securities convertible, exchangeable,
or exercisable for such equity securities) of the Company during the Demand
Registration Holdback Period in the event of a Demand Registration. A written
agreement memorializing each such Person's agreement to the foregoing
restrictions shall be executed in a form reasonably satisfactory to the holders
of a majority of Registrable Securities and, if applicable, the managing
underwriters.

          (4) RESTRICTIONS APPLICABLE TO THE HOLDERS OF REGISTRABLE SECURITIES.
The holders of the Registrable Securities shall not sell, transfer or otherwise
dispose of any equity securities (or any securities convertible, exchangeable or
exercisable for such equity securities) of the Company beneficially owned by
them during a Demand Registration Holdback Period in the event of any Demand
Registration, except for those securities included in the Demand Registration.


                                        8


<PAGE>

     SECTION 6. REGISTRATION PROCEDURES.

     In connection with the Company's registration obligations pursuant to
SECTIONS 3 AND 4 hereof, the Company will use its best efforts to effect such
registration to permit the sale of such Registrable Securities in accordance
with the intended method or methods of disposition thereof, and pursuant thereto
the Company will as expeditiously as possible:

          (a) before filing a Registration Statement or Prospectus or any
     amendments or supplements thereto, furnish to the holders of the
     Registrable Securities covered by such Registration Statement and the
     underwriters, if any, copies of all such documents proposed to be filed,
     which documents will be subject to the review of such holders and
     underwriters, and the Company will not file any Registration Statement or
     amendment thereto or any Prospectus or any supplement thereto to which the
     holders of a majority of the Registrable Securities covered by such
     Registration Statement or the underwriters, if any, shall reasonably
     object;

          (b) prepare and file with the SEC a Registration Statement or
     Registration Statements relating to the applicable Demand Registration or
     Piggyback Registration including all exhibits and financial statements

     required by the SEC to be filed therewith, and use its best efforts to
     cause such Registration Statement to become effective under the Securities
     Act; and prepare and file with the SEC such amendments and post-effective
     amendments to such Registration Statement, and such supplements to the
     Prospectus, as may be requested by any underwriter of Registrable
     Securities or as may be required by the rules, regulations or instructions
     applicable to the registration form utilized by the Company or by the
     Securities Act or rules and regulations otherwise necessary to keep the
     Registration Statement effective for a period of not less than 90 days (or
     such shorter period which will terminate when all Registrable Securities
     covered by such Registration Statement have been sold or withdrawn); and
     cause the Prospectus as so supplemented to be filed pursuant to Rule 424
     under the Securities Act; and comply with the provisions of the Securities
     Act and the Exchange Act with respect to the disposition of all securities
     covered by such Registration Statement during the applicable period in
     accordance with the intended methods of disposition by the sellers thereof
     set forth in such Registration Statement or supplement to the Prospectus;

          (c) notify the selling holders of Registrable Securities and the
     managing underwriters, if any, promptly, and (if requested by any such
     Person) confirm such advice in writing,

               (1) when the Prospectus or any Prospectus supplement or post-
          effective amendment has been filed, and, with respect to the
          Registration Statement or any post-effective amendment, when the same
          has become effective,

               (2) of any request by the SEC for amendments or supplements to
          the Registration Statement or the Prospectus or for additional
          information,


                                        9


<PAGE>

               (3) of the issuance by the Commission of any stop order
          suspending the effectiveness of the Registration Statement or the
          initiation of any proceedings for that purpose,

               (4) if at any time the representations and warranties of the
          Company contemplated by PARAGRAPH (o) below cease to be true and
          correct,

               (5) of the receipt by the Company of any notification with
          respect to the suspension of the qualification of the Registrable
          Securities for sale in any jurisdiction or the initiation or
          threatening of any proceeding for such purpose, and

               (6) of the existence of any fact which results in the
          Registration Statement, the Prospectus or any document incorporated
          therein by reference containing an untrue statement of material fact
          or omitting to state a material fact required to be stated therein or
          necessary to make the statements therein not misleading;


          (d) make every reasonable effort to obtain the withdrawal of any order
     suspending the effectiveness of the Registration Statement at the earliest
     possible moment;

          (e) if requested by the managing underwriter or underwriters or a
     holder of Registrable Securities being sold in connection with an
     Underwritten Offering, immediately incorporate in a Prospectus supplement
     or post-effective amendment such information as the managing underwriters
     and the holders of a majority of the Registrable Securities being sold
     agree should be included therein relating to the plan of distribution with
     respect to such Registrable Securities, including, without limitation,
     information with respect to the amount of Registrable Securities being sold
     to such underwriters, the purchase price being paid therefor by such
     underwriters and with respect to any other terms of the underwritten (or
     best efforts underwritten) offering of the Registrable Securities to be
     sold in such offering; and make all required filings of such Prospectus
     supplement or post-effective amendment as soon as notified of the matters
     to be incorporated in such Prospectus supplement or post-effective
     amendment;

          (f) furnish to each selling holder of Registrable Securities and each
     managing underwriter, without charge, at least one signed copy of the
     Registration Statement and any post-effective amendment thereto, including
     financial statements and schedules, all documents incorporated therein by
     reference and all exhibits (including those incorporated by reference);

          (g) deliver to each selling holder of Registrable Securities and the
     underwriters, if any, without charge, as many copies of the Prospectus
     (including each preliminary prospectus) and any amendment or supplement
     thereto as such Persons may reasonably request (it being understood that,
     unless one of clauses (2)-(6) of Section 6(c) is applicable, the Company
     consents to the use of the Prospectus or any amendment or


                                       10


<PAGE>

     supplement thereto by each of the selling holders of Registrable Securities
     and the underwriters, if any, in connection with the offering and sale of
     the Registrable Securities covered by the Prospectus or any amendment or
     supplement thereto) and such other documents filed by the Company pursuant
     to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act as such selling
     holder may reasonably request in order to facilitate the disposition of the
     Registrable Securities by such holder and underwriters, if any;

          (h) prior to any public offering of Registrable Securities, register
     or qualify or cooperate with the selling holders of Registrable Securities,
     the underwriters, if any, and their respective counsel in connection with
     the registration or qualification of such Registrable Securities for offer
     and sale under the securities or blue sky laws of such jurisdictions as any
     selling holder of Registrable Securities or any underwriter reasonably
     requests in writing and do any and all other acts or things reasonably

     necessary to enable the disposition in such jurisdictions of the
     Registrable Securities covered by the Registration Statement; PROVIDED THAT
     the Company will not be required to qualify generally to do business in any
     jurisdiction where it is not then so qualified or to take any action which
     would subject it to taxation or general service of process in any such
     jurisdiction where it is not then so subject;

          (i) cooperate with the selling holders of Registrable Securities and
     the managing underwriters, if any, to facilitate the timely preparation and
     delivery of certificates representing Registrable Securities to be sold and
     not bearing any restrictive legends; and enable such Registrable Securities
     to be in such denominations and registered in such names as the managing
     underwriters may request at least two business days prior to any sale of
     Registrable Securities to the underwriters;

          (j) use its best efforts to cause the Registrable Securities covered
     by the applicable Registration Statement to be registered with or approved
     by such other foreign governmental agencies or authorities, and the
     National Association of Securities Dealers, Inc., as may be necessary to
     enable the seller or sellers thereof or the underwriters, if any, to
     consummate the disposition of such Registrable Securities;

          (k) if any fact contemplated by PARAGRAPH (c)(6) above shall exist,
     prepare a supplement or post-effective amendment to the Registration
     Statement or the related Prospectus or any document incorporated therein by
     reference or file any other required document so that, as thereafter
     delivered to the purchasers of the Registrable Securities, the Prospectus
     will not contain an untrue statement of a material fact or omit to state
     any material fact required to be stated therein or necessary to make the
     statements therein not misleading;

          (l) cause all Registrable Securities covered by the Registration
     Statement to be quoted on the Nasdaq National Market or listed on each
     securities exchange on which similar securities issued by the Company are
     then listed if requested by the holders of a majority of such Registrable
     Securities or the managing underwriters, if any;


                                       11


<PAGE>

          (m) not later than the effective date of the applicable Registration
     Statement, provide a CUSIP number for all Registrable Securities and
     provide the applicable transfer agent with printed certificates for the
     Registrable Securities which are in a form eligible for deposit with
     Depositary Trust Company;

          (n) enter into agreements (including underwriting agreements) and take
     all other appropriate actions in order to expedite or facilitate the
     disposition of such Registrable Securities and in such connection, whether
     or not an underwriting agreement is entered into and whether or not the
     registration is an Underwritten Registration:


               (1) make such representations and warranties to the holders of
          such Registrable Securities and the underwriters, if any, in form,
          substance and scope as are customarily made by issuers to underwriters
          in primary Underwritten Offerings;

               (2) obtain opinions of counsel to the Company (which counsel and
          opinions (in form, scope and substance) shall be reasonably
          satisfactory to the managing underwriters, if any, and the holders of
          a majority of the Registrable Securities being sold) addressed to each
          selling holder and the underwriters, if any, covering the matters
          customarily covered in opinions requested in primary Underwritten
          Offerings;

               (3) obtain "cold comfort" letters and updates thereof from the
          Company's independent certified public accountants addressed to the
          underwriters, if any, such letters to be in customary form and
          covering matters of the type customarily covered in "cold comfort"
          letters by underwriters in connection with primary Underwritten
          Offerings;

               (4) use its best efforts to obtain "cold comfort" letters and
          updates thereof from the Company's independent certified public
          accountants addressed to the selling holders of Registrable
          Securities, such letters to be in customary form and covering matters
          of the type customarily covered in "cold comfort" letters by
          underwriters in connection with primary Underwritten Offerings;

               (5) if such an agreement is entered into, cause the same to set
          forth in full indemnification provisions and procedures substantially
          comparable to those set forth in SECTION 8 hereof with respect to all
          parties to be indemnified pursuant to said Section, including without
          limitation, all underwriters, sellers, brokers, dealers, managers and
          similar securities industry professionals participating in the
          distribution contemplated by such agreement, their officers and
          directors and each Person who controls such Persons (within the
          meaning of Section 15 of the Securities Act or Section 20 of the
          Exchange Act); and

               (6) deliver such documents and certificates as may be reasonably
          requested in writing by the holders of a majority of the Registrable
          Securities being sold and the managing underwriters, if any, to
          evidence compliance with


                                       12


<PAGE>


          PARAGRAPH (k) above and with any customary conditions contained in the
          underwriting agreement or other agreement entered into by the Company.

     The above shall be done as and to the extent required by the applicable
     agreement and by the then current practice;


          (o) make available for inspection by any underwriter (including any
     "qualified independent underwriter" that is required to be retained in
     accordance with the rules and regulations of the NASD) participating in any
     disposition pursuant to such Registration Statement, and any attorney or
     accountant retained by the underwriter, all financial and other records,
     pertinent corporate documents and properties of the Company, and cause the
     Company's officers, directors and employees to supply all information
     reasonably requested by any such underwriter, attorney or accountant in
     connection with the registration; PROVIDED that prior to any such Person
     being given access to such records, documents, properties or information
     such Person shall execute a reasonable and customary agreement to maintain
     the confidentiality of such records, documents, properties or information;

          (p) otherwise use its best efforts to comply with all applicable rules
     and regulations of the SEC, and make generally available to its security
     holders, earnings statements satisfying the provisions of Section 11(a) of
     the Securities Act, no later than 45 days after the end of any 12- month
     period (or 90 days, if such period is a fiscal year) (1) commencing at the
     end of any fiscal quarter in which Registrable Securities are sold to
     underwriters in an Underwritten Offering, or, if not sold to underwriters
     in such an offering, (2) beginning with the first month of the Company's
     first fiscal quarter commencing after the effective date of the
     Registration Statement, which statements shall cover said 12-month periods;

          (q) cooperate and assist in any filings required to be made with the
     NASD and, subject to Section 6(o), in the performance of any due diligence
     investigation by any underwriter (including any "qualified independent
     underwriter" that is required to be retained in accordance with the rules
     and regulations of the NASD); and

          (r) promptly prior to the filing of any document which is to be
     incorporated by reference into the Registration Statement or the Prospectus
     (after initial filing of the Registration Statement) provide copies of such
     document to counsel to the selling holders of Registrable Securities and to
     the managing underwriters, if any, make the Company's representatives
     available for discussion of such document and make such changes in such
     document prior to the filing thereof as counsel for such selling holders or
     underwriters may reasonably request.

     The Company may require each seller of Registrable Securities as to which
any registration is being effected to furnish to the Company such information
regarding the distribution of such securities, and such other information about
each such Seller as is required by the form of Registration Statement being used
for such registration, as the Company may from time to time reasonably request
in writing.

     Each holder of Registrable Securities agrees by acquisition of such
Registrable Securities that, upon receipt of any notice from the Company of the
happening of any event of the kind described in SECTION 6(c)(6) hereof, such
holder will forthwith discontinue disposition of


                                       13



<PAGE>

Registrable Securities until such holder's receipt of the copies of the
supplemented or amended Prospectus contemplated by SECTION 6(k) hereof, or until
it is advised in writing by the Company that the use of the Prospectus may be
resumed, and has received copies of any additional or supplemental filings which
are incorporated by reference in the Prospectus, and, if so directed by the
Company, such holder will deliver to the Company (at the Company's expense) all
copies, other than permanent file copies then in such holder's possession, of
the Prospectus covering such Registrable Securities current at the time of
receipt of such notice.  In the event the Company shall give any such notice,
the time periods during which such Registration Statement shall be maintained
effective shall be extended by the number of days during the period from and
including the date of the giving of such notice to and including the date when
each seller of Registrable Securities covered by such Registration Statement
either receives the copies of the supplemented or amended prospectus
contemplated by SECTION 6(k) hereof or is advised in writing by the Company that
the use of the Prospectus may be resumed.

     SECTION 7. REGISTRATION EXPENSES.

     (a) All expenses incident to the Company's performance of or compliance
with this Agreement will be paid by the Company, regardless of whether the
Registration Statement becomes effective, including without limitation:

          (1) all registration and filing fees (including with respect to
     filings required to be made with the SEC);

          (2) fees and expenses of compliance with securities or blue sky laws
     (including fees and disbursements of counsel for the underwriters or
     selling holders in connection with blue sky qualifications of the
     Registrable Securities and determination of their eligibility for
     investment under the laws of such jurisdictions as the managing
     underwriters or holders of a majority of the Registrable Securities being
     sold may designate);

          (3) printing (including expenses of printing certificates for the
     Registrable Securities in a form eligible for deposit with the Depositary
     Trust Company and of printing prospectuses), messenger, telephone and
     delivery expenses;

          (4) fees and disbursements of counsel for the (i) Company and (ii) the
     sellers of the Registrable Securities (subject to the provisions of SECTION
     7(b) hereof);

          (5) fees and disbursements of all independent certified public
     accountants of the Company (including the expenses of any "cold comfort"
     letters required by or incident to such performance);

          (6) fees and expenses of other Persons retained by the Company; and

          (7) all registration, filing and other fees and expenses associated
     with any NASD filing required to be made in connection with the

     Registration Statement, including, if applicable, the fees and expenses of
     any "qualified independent underwriter" (and its counsel) that is required
     to


                                       14


<PAGE>

     be retained in accordance with the rules and regulations of the NASD (all
     such expenses being herein called "REGISTRATION EXPENSES").

     The Company will, in any event, pay its internal expenses (including,
without limitation, all salaries and expenses of its officers and employees
performing legal or accounting duties), the expense of any annual audit, the
fees and expenses incurred in connection with the listing of the securities to
be registered on each securities exchange on which similar securities issued by
the Company are then listed, rating agency fees and the fees and expenses of any
Person, including special experts, retained by the Company.

     (b) In connection with each Registration Statement required hereunder, the
Company will reimburse the holders of Registrable Securities being registered
pursuant to such Registration Statement for the reasonable fees and
disbursements of not more than one counsel chosen by the holders of a majority
of such Registrable Securities.

     (c) Each seller of the Registrable Securities shall pay all discounts,
commissions, fees and expenses of the underwriters, selling brokers, dealer
managers and similar industry professionals relating to the distribution of its
Registrable Securities.

     SECTION 8. INDEMNIFICATION.

     (a) INDEMNIFICATION BY COMPANY. The Company agrees to indemnify and hold
harmless each holder of Registrable Securities, its officers, directors,
employees and Agents and each Person who controls such holder within the meaning
of either Section 15 of the Securities Act or Section 20 of the Exchange Act
(each such person being sometimes hereinafter referred to as an "INDEMNIFIED
HOLDER") from and against all losses, claims, damages, liabilities and expenses
(including reasonable costs of investigation and legal expenses) arising out of
or based upon any untrue statement or alleged untrue statement of a material
fact contained in any Registration Statement or Prospectus or in any amendment
or supplement thereto or in any preliminary prospectus, or arising out of or
based upon any omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, except insofar as such losses, claims, damages, liabilities or
expenses arise out of or are based upon any such untrue statement or omission or
allegation thereof based upon information furnished in writing to the Company by
such holder expressly for use therein; PROVIDED, HOWEVER, that the Company shall
not be liable in any such case to the extent that any such loss, claim, damage,
liability or expense arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission in any Prospectus or
preliminary prospectus, if such untrue statement or alleged untrue statement,
omission or alleged omission is completely corrected in an amendment or

supplement to the Prospectus or preliminary prospectus and if, having previously
been furnished by or on behalf of the Company with copies of the Prospectus or
preliminary prospectus as so amended or supplemented, such holder thereafter
fails to deliver such Prospectus or preliminary prospectus as so amended or
supplemented, prior to or concurrently with the sale of a Registrable Security
to the person asserting such loss, claim, damage, liability or expense who
purchased such Registrable Security which is the subject thereof from such
holder. This indemnity will be in addition to any liability which the Company
may otherwise have.


                                       15


<PAGE>

     If any action or proceeding (including any governmental investigation or
inquiry) shall be brought or asserted against an Indemnified Holder in respect
of which indemnity may be sought from the Company, such Indemnified Holder shall
promptly notify the Company in writing, and the Company shall assume the defense
thereof, including the employment of counsel satisfactory to such Indemnified
Holder and the payment of all expenses. Such Indemnified Holder shall have the
right to employ separate counsel in any such action and to participate in the
defense thereof, but the fees and expenses of such counsel shall be at the
expense of such Indemnified Holder unless (a) the Company has agreed to pay such
fees and expenses or (b) the Company shall have failed to assume the defense of
such action or proceeding and has failed to employ counsel satisfactory to such
Indemnified Holder in any such action or proceeding or (c) the named parties to
any such action or proceeding (including any impleaded parties) include both
such Indemnified Holder and the Company, and such Indemnified Holder shall have
been advised by counsel that there may be one or more legal defenses available
to such Indemnified Holder which are different from or additional to those
available to the Company (in which case, if such Indemnified Holder notifies the
Company in writing that it elects to employ separate counsel at the expense of
the Company, the Company shall not have the right to assume the defense of such
action or proceeding on behalf of such Indemnified Holder, it being understood,
however, that the Company shall not, in connection with any one such action or
proceeding or separate but substantially similar or related actions or
proceedings in the same jurisdiction arising out of the same general allegations
or circumstances, be liable for the reasonable fees and expenses of more than
one separate firm of attorneys at any time for such Indemnified Holder and any
other Indemnified Holders, which firm shall be designated in writing by such
Indemnified Holders). The Company shall not be liable for any settlement of any
such action or proceeding effected without its written consent, but if settled
with its written consent, or if there be a final judgment for the plaintiff in
any such action or proceeding, the Company agrees to indemnify and hold harmless
such Indemnified Holders from and against any loss or liability by reason of
such settlement or judgment.

     (b) INDEMNIFICATION BY HOLDER OF REGISTRABLE SECURITIES. Each holder of
Registrable Securities agrees to indemnify and hold harmless the Company, its
directors and officers and each Person, if any, who controls the Company within
the meaning of either Section 15 of the Securities Act or Section 20 of the
Exchange Act to the same extent as the foregoing indemnity from the Company to
such holder, but only with respect to (i) information relating to such holder

furnished in writing by such holder expressly for use in any Registration
Statement or Prospectus, or any amendment or supplement thereto, or any
preliminary prospectus and (ii) any loss, claim, damage, liability or expense
described in the proviso to the first sentence of SECTION 8(a). In case any
action or proceeding shall be brought against the Company or its directors or
officers or any such controlling person, in respect of which indemnity may be
sought against a holder of Registrable Securities, such holder shall have the
rights and duties given the Company and the Company or its directors or officers
or such controlling person shall have the rights and duties given to each holder
by the preceding paragraph. In no event shall the liability of any selling
holder of Registrable Securities hereunder be greater in amount than the dollar
amount of the proceeds received by such holder upon the sale of the Registrable
Securities giving rise to such indemnification obligation.


                                       16


<PAGE>

     The Company shall be entitled to receive indemnities from underwriters,
selling brokers, dealer managers and similar securities industry professionals
participating in the distribution, to the same extent as provided above with
respect to information so furnished in writing by such Persons specifically for
inclusion in any Prospectus or Registration Statement or any amendment or
supplement thereto, or any preliminary prospectus.

     (c) CONTRIBUTION. If the indemnification provided for in this SECTION 8 is
unavailable to an indemnified party under SECTION 8(a) or SECTION 8(b) hereof
(other than by reason of exceptions provided in those Sections) in respect of
any losses, claims, damages, liabilities or expenses referred to therein, then
each applicable indemnifying party, in lieu of indemnifying such indemnified
party, shall contribute to the amount paid or payable by such indemnified party
as a result of such losses, claims, damages, liabilities or expenses in such
proportion as is appropriate to reflect the relative fault of the Company on the
one hand and of the Indemnified Holder on the other in connection with the
statements or omissions which resulted in such losses, claims, damages,
liabilities or expenses, as well as any other relevant equitable considerations.
The relative fault of the Company on the one hand and of the Indemnified Holder
on the other shall be determined by reference to, among other things, whether
the untrue or alleged untrue statement of a material fact or the omission or
alleged omission to state a material fact relates to information supplied by the
Company or by the Indemnified Holder and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
statement or omission. The amount paid or payable by a party as a result of the
losses, claims, damages, liabilities and expenses referred to in SECTION 8(a) or
SECTION 8(b) shall be deemed to include, subject to the limitations set forth in
the second paragraph of SECTION 8(a), any legal or other fees or expenses
reasonably incurred by such party in connection with investigating or defending
any action or claim.

     The Company and each holder of Registrable Securities agree that it would
not be just and equitable if contribution pursuant to this SECTION 8(c) were
determined by pro rata allocation or by any other method of allocation which
does not take account of the equitable considerations referred to in the

immediately preceding paragraph. Notwithstanding the provisions of this SECTION
8(c), an Indemnified Holder shall not be required to contribute any amount in
excess of the amount by which the total price at which the Registrable
Securities sold by such Indemnified Holder or its affiliated Indemnified Holders
and distributed to the public were offered to the public exceeds the amount of
any damages which such Indemnified Holder, or its affiliated Indemnified Holder,
has otherwise been required to pay by reason of such untrue or alleged untrue
statement or omission or alleged omission. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Act) shall be
entitled to contribution from any person who was not guilty of such fraudulent
misrepresentation.

     SECTION 9. RULE 144.

     The Company covenants that it will file the reports required to be filed by
it under the Securities Act and the Exchange Act and the rules and regulations
adopted by the SEC thereunder, and, so long as the Company is subject to the
reporting requirements of the Exchange Act and the rules and regulations
thereunder, it will take such further action as any holder of Registrable
Securities may reasonably request, all to the extent required from time to


                                       17


<PAGE>

time to enable such holder to sell Registrable Securities without registration
under the Securities Act within the limitation of the exemptions provided by (a)
Rule 144 under the Securities Act, as such Rule may be amended from time to
time, or (b) any similar rule or regulation hereafter adopted by the SEC.  Upon
the request of any holder of Registrable Securities, the Company will deliver to
such holder a written statement as to whether it has complied with such
information and requirements.

     SECTION 10. PARTICIPATION IN UNDERWRITTEN REGISTRATIONS.

     No Person may participate in any Underwritten Registration hereunder unless
such Person (a) agrees to sell such Person's securities on the basis provided in
any underwriting arrangements approved by the Persons entitled hereunder to
approve such arrangements and (b) completes and executes all questionnaires,
powers of attorney, indemnities, underwriting agreements and other documents
required under the terms of such underwriting arrangements.

     SECTION 11. MISCELLANEOUS.

     (a) REMEDIES. Each of the parties hereto, in addition to being entitled to
exercise all rights provided herein, in the Purchase Agreement and granted by
law, including recovery of damages, will be entitled to specific performance of
its rights under this Agreement. Each of the parties hereto agrees that monetary
damages would not be adequate compensation for any loss incurred by reason of a
breach by it of the provisions of this Agreement and hereby agrees to waive the
defense in any action for specific performance that a remedy at law would be
adequate.


     (b) NO INCONSISTENT AGREEMENTS. The Company will not on or after the date
of this Agreement enter into any agreement with respect to its securities which
is inconsistent with the rights granted to the holders of Registrable Securities
in this Agreement or otherwise conflicts with the provisions hereof. The Company
represents and warrants that the rights granted to the holders of Registrable
Securities hereunder do not in any way conflict with and are not inconsistent
with the rights granted to the holders of the Company's securities under any
agreement in effect on the date hereof.

     (c) AMENDMENTS AND WAIVERS. The provisions of this Agreement, including the
provisions of this sentence, may not be amended, modified or supplemented, and
waivers or consents to departures from the provisions hereof may not be given
unless the Company has obtained the written consent of holders of at least a
majority of the outstanding Registrable Securities. Notwithstanding the
foregoing, a waiver or consent to departure from the provisions hereof that
relates exclusively to the rights of holders of Registrable Securities whose
securities are being sold pursuant to a Registration Statement and that does not
directly or indirectly affect the rights of other holders of Registrable
Securities may be given by the holders of a majority of the Registrable
Securities being sold.

     (d) NOTICES. Unless otherwise provided herein, any notice, request,
instruction or other document to be given hereunder by any party to the others
shall be in writing and delivered in person or by courier, telegraphed, telexed
or by facsimile transmission (with receipt


                                       18


<PAGE>

confirmed), or mailed by certified mail, postage prepaid, return receipt
requested (such mailed notice to be effective on the date of such receipt is
acknowledged), as follows:

     (i) if to a holder of Registrable Securities, at the most current address
     given by such holder to the Company in accordance with the provisions of
     this Section 11(d), which address initially is, with respect to the
     Purchaser:

          Amgen Inc.
          Amgen Center
          1840 DeHavilland Drive
          Thousand Oaks, California 91320-1789
          Attn: Corporate Secretary
          Telecopy No.: (805) 499-9315

     With a copy to:

          Latham & Watkins
          633 West Fifth Street
          Los Angeles, California 90071
          Attn: Michael W. Sturrock, Esq.
          Telecopy No.: (213) 891-8763


     (ii) if to the Company, initially to:

          Regeneron Pharmaceuticals, Inc.
          777 Old Saw Mill River Road
          Tarrytown, New York 10591-6707
          Attn: Corporate Secretary
          Telecopy No.: (914) 345-7721

     With a copy to:

          Skadden, Arps, Slate, Meagher & Flom
          919 Third Avenue
          New York, New York 10022
          Attn: Morris Kramer, Esq. and Matthew J. Mallow, Esq.
          Telecopy No.: (212) 735-2000

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.

     (e) SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit of
and be binding upon the successors and assigns of each of the parties, including
without limitation and without the need for an express assignment, subsequent
holders of Registrable Securities; provided, however, that this Agreement shall
not inure to the benefit of or be binding upon a successor or assign of a holder
of Registrable Securities unless such successor


                                       19


<PAGE>

or assign (i) acquired Registrable Securities from a holder of Registrable 
securities who was bound by the terms of this Agreement and (ii) agrees
to be bound by the terms of this Agreement.

     (f) COUNTERPARTS. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

     (g) HEADINGS. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

     (h) GOVERNING LAW. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York.

     (i) SEVERABILITY. In the event that any one or more of the provisions
contained herein, or the application thereof in any circumstance, is held
invalid, illegal or unenforceable, the validity, legality and enforceability of
any such provision in every other respect and of the remaining provisions
contained herein shall not be affected or impaired thereby.

     (j) ENTIRE AGREEMENT. This Agreement is intended by the parties as a final

expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto in respect of
the subject matter contained herein. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein
with respect to the registration rights granted by the Company with respect to
the securities sold pursuant to the Purchase Agreement. This Agreement
supersedes all prior agreements and understandings between the parties with
respect to such subject matter.

     (k) LIMITATIONS ON SUBSEQUENT REGISTRATIONS. After the date hereof, the
Company shall not, without the prior written consent of the holders of at least
50% of the Registrable Securities, enter into any agreement (other than this
Agreement) with any holder or prospective holder of any securities for the
Company which would allow such holder or prospective holder to make a demand
registration, after the holders of Registrable Securities have made a Demand
Registration, which could result in such Registration Statement being declared
effective prior to such Demand Registration.


                           [Signature Page To Follow]


                                       20


<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
first written above.

                                   REGENERON PHARMACEUTICALS, INC.



                                   By:
                                       ------------------------------------
                                       Name:
                                       Title:




                                   AMGEN INC.



                                   By:
                                       ------------------------------------
                                       Name:
                                       Title:



                                       S-1




<PAGE>

                      STOCK AND WARRANT PURCHASE AGREEMENT

                                 by and between

                         REGENERON PHARMACEUTICALS, INC.

                                       and

                                 MEDTRONIC, INC.

                            Dated as of June 27, 1996


<PAGE>

                                TABLE OF CONTENTS

ARTICLE I......................................................................1
    1.1  Defined Terms.........................................................1
    1.2  Other Defined Terms...................................................2
ARTICLE II.....................................................................3
    2.1  Issuance and Sale of Securities.......................................3
ARTICLE III....................................................................3
    3.1  Closing...............................................................3
    3.2  Documents to be Delivered.............................................3
ARTICLE IV.....................................................................4
    4.1  Organization and Standing.............................................4
    4.2  Capitalization........................................................4
    4.3  Issuance of Shares....................................................5
    4.4  Authority for Agreement...............................................5
    4.5  Governmental Consents.................................................6
    4.6  Litigation............................................................6
    4.7  SEC Filings...........................................................6
    4.8  No Undisclosed Liabilities............................................7
    4.9  Absence of Changes....................................................7
    4.10 Intellectual Property.................................................7
    4.11 No Defaults...........................................................8
    4.12 Offerings.............................................................8
    4.13 Brokers...............................................................8
ARTICLE V......................................................................8
    5.1  Investment............................................................8
    5.2  Authority.............................................................9
    5.3  Accredited Investor...................................................9
    5.4  Brokers...............................................................9
ARTICLE VI.....................................................................9
    6.1  Survival of Representations...........................................9
    6.2  Indemnification.......................................................9


                                       i

<PAGE>

ARTICLE VII...................................................................10

    7.1  Legend...............................................................10
    7.2  Assignment...........................................................10
    7.3  Notices..............................................................10
    7.4  Choice of Law........................................................11
    7.5  Entire Agreement.....................................................11
    7.6  Counterparts.........................................................12
    7.7  Invalidity...........................................................12
    7.8  Headings.............................................................12
    7.9  Expenses.............................................................12
    7.10 Specific Enforcement.................................................12
    7.11 Further Assurances...................................................13


                                       ii

<PAGE>

                      STOCK AND WARRANT PURCHASE AGREEMENT

     This Stock and Warrant Purchase Agreement, dated as of June 27, 1996 is by
and between Medtronic, Inc., a Minnesota corporation ("Buyer"), and Regeneron
Pharmaceuticals, Inc., a New York
 corporation (the "Company").

                                    RECITALS

     WHEREAS, Buyer wishes to purchase from the Company, and the Company wishes
to sell to Buyer, 460,500 shares of the Company's Common Stock (the "Shares");

     WHEREAS, Buyer wishes to purchase from the Company, and the Company wishes
to sell to Buyer, pursuant to the terms and conditions of the Warrant Agreement
(the "Warrant Agreement"), 107,400 Warrants (the "Warrants," and together with
the Shares, the "Securities"). Each of the Warrants shall be exercisable for one
share of Common Stock (individually, a "Warrant Share" and collectively, the
"Warrant Shares"); and

     WHEREAS, Buyer and the Company desire to provide for the foregoing
purchases and sales and to establish various rights and obligations in
connection therewith.

                                    AGREEMENT

     NOW, THEREFORE, in consideration of the mutual covenants and promises
contained herein and for other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

     1.1 Defined Terms. As used herein, the terms below shall have the following
meanings:

          "Class A Common Stock" shall mean the shares of the Class A Common
Stock, par value $.001 per share, of the Company.


          "Collaborative Study Agreement" shall mean the Collaborative Study
Agreement to be entered into as of the date hereof by and between the Company
and Buyer.


                                       1

<PAGE>

          "Collateral Agreements" shall mean the Collaborative Study Agreement,
the Warrant Agreement, and the Registration Rights Agreement.

          "Common Stock" shall mean the shares of the Common Stock, par value
$.001 per share, of the Company.

          "Commission" or "SEC" shall mean the United States Securities and
Exchange Commission.

          "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission thereunder.

          "Person" shall mean any individual, firm, corporation, partnership,
limited liability company, trust, unincorporated organization or other entity or
a government or agency or political subdivision thereof, and shall include any
successor (by merger or otherwise) of such Person.

          "Preferred Stock" shall mean the shares of the Preferred Stock, par
value $.001 per share, of the Company.

          "Registration Rights Agreement" shall mean the Registration Rights
Agreement to be entered into as of the date hereof by and between the Company
and Buyer.

          "Securities Act" shall mean the Securities Act of 1933, as amended,
and the rules and regulations of the Commission thereunder.

          "Warrant Agreement" shall mean the Warrant Agreement to be entered
into as of the date hereof by and between the Company and Buyer.

     1.2 Other Defined Terms. The following terms shall have the meanings
defined for such terms in the Sections set forth below:

           TERM                                        SECTION
           ----                                        -------
           Buyer                                       Preamble
           Closing                                     3.1
           Company SEC Reports                         4.7
           Reserved Plan Shares                        4.2
           Securities                                  Recitals
           Securities Purchase Price                   2.1
           Shares                                      Recitals
           Warrant Agreement                           Recitals
           Warrants                                    Recitals
           Warrant Share                               Recitals
           Warrant Shares                              Recitals

           March 31, 1996 Balance Sheet                4.8


                                       2

<PAGE>

                                   ARTICLE II

                         ISSUANCE AND SALE OF SECURITIES

     2.1 Issuance and Sale of Securities. Upon the terms set forth herein, the
Company will issue and sell to Buyer, and Buyer will purchase from the Company,
the Securities for an aggregate price of $10.0 Million in immediately available
funds (the "Securities Purchase Price").

                                   ARTICLE III

                                     CLOSING

     3.1 Closing. The closing of the transactions contemplated hereby (the
"Closing") will take place (i) in the offices of Skadden, Arps, Slate, Meagher &
Flom, 919 Third Avenue, New York, New York at 5:00 p.m. New York time on the
date hereof or (ii) at either party's election, by delivery via facsimile
transmission (with originals sets via overnight courier service) of the executed
documents to be delivered at the Closing and wire transfer of the Securities
Purchase Price.

     3.2 Documents to be Delivered. At the Closing, the Company shall deliver to
Buyer, against payment in full of the Securities Purchase Price, (i)
certificates for the Shares in such denominations as Buyer has requested, dated
the date hereof and registered in the names requested by Buyer, (ii)
certificates for the Warrants in such denominations as Buyer has requested,
dated the date hereof and registered in the names requested by Buyer, (iii) each
of the Collateral Agreements, which shall have been duly authorized, executed
and delivered by the Company and shall be in full force and effect and (iv) an
opinion of Paul Lubetkin, General Counsel to the Company, in form and substance
reasonably satisfactory to Buyer, substantially to the effect specified in
Sections 4.1 through 4.5, with such exceptions and qualifications as are
customary and reasonable under the law of the applicable jurisdiction. In
rendering such opinion, such counsel may rely upon certificates of public
officers and, as to matters of fact, upon certificates of duly authorized
representatives of the Company, provided, that copies of such certificates shall
be contemporaneously delivered to Buyer.


                                       3

<PAGE>

                                   ARTICLE IV

                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

     The Company hereby represents and warrants to Buyer as of the date hereof
as follows:


     4.1 Organization and Standing. The Company is a corporation duly organized
and validly existing under the laws of the State of New York and has full
corporate power and authority to own and lease its property, to conduct its
business as presently conducted and as proposed to be conducted by it and to
execute and deliver this Agreement and each of the Collateral Agreements. The
Company has full corporate power and authority to perform and to carry out the
transactions contemplated by this Agreement and each of the Collateral
Agreements. The Company is qualified to do business and in good standing in New
York and in each jurisdiction where it does business or owns property except
those jurisdictions where the failure to be so qualified and in good standing
would not have a material adverse effect on its business or property. The
Company has furnished to Buyer true and complete copies of its Restated
Certificate of Incorporation and Bylaws, each as amended to date and presently
in effect.

     4.2 Capitalization. As of April 30, 1996, the authorized capital stock of
the Company consisted of the following: (a) 60,000,000 shares of Common Stock,
of which (i) 19,964,988 shares were issued and outstanding, (ii) 5,070,942
shares were reserved for future issuance upon conversion of the Class A Common
Stock, each share of the Class A Stock being convertible into one share of
Company Common Stock, (iii) 3,789,626 shares were reserved for future issuance
under the Company's 1990 Amended and Restated Long-Term Incentive Plan (the
"Reserved Plan Shares"), and (iv) 700,000 shares were reserved for future
issuance in accordance with a certain warrant issued to Amgen Inc.; and (b)
40,000,000 shares of Class A Common Stock, of which 5,070,942 were issued and
outstanding, and (c) 30,000,000 shares of Preferred Stock, none of which were
issued and outstanding. No material change in such capitalization has occurred
between April 30, 1996 and the date hereof, and there has been no reduction
whatsoever in the number of shares of any class of the Company's outstanding
capital stock. All of the issued and outstanding shares of Common Stock, Class A
Stock, and Preferred Stock have been duly authorized, and all of the issued and
outstanding shares of the Common Stock and the Class A Common Stock are validly
issued and are fully paid and non-assessable. Except as set forth in the Company
SEC Reports or in the aforementioned warrant issued to Amgen Inc. or as provided
in this 


                                       4

<PAGE>

Agreement, there is not, nor upon the consummation of the transactions
contemplated herein, will there be, (i) any subscription, warrant, option,
convertible security or other right (contingent or otherwise) to purchase or
acquire any shares of capital stock of the Company, (ii) any commitment of the
Company to issue any subscription, warrant, option, convertible security or
other such right or to issue or distribute to holders of any shares of its
capital stock any evidences of indebtedness or assets of the Company, or (iii)
any obligation of the Company (contingent or otherwise) to purchase, redeem or
otherwise acquire any shares of its capital stock or any interest therein or to
pay any dividend or make any other distribution in respect thereof. Except as
set forth in the Company SEC Reports or as provided in this Agreement, no Person
is entitled to, nor upon the consummation of the transactions contemplated
herein will any Person be entitled to, (i) any preemptive or similar right with

respect to the issuance of any capital stock of the Company, or (ii) any rights
with respect to the registration of any capital stock of the Company under the
Securities Act.

     4.3 Issuance of Shares. The issuance, sale and delivery of the Securities
in accordance with this Agreement, and the issuance and delivery of the Warrant
Shares issuable upon exercise of the Warrants, have been duly authorized and
reserved for issuance, as the case may be, by all necessary corporate action on
the part of the Company (no consent or approval of the stockholders of the
Company being required by law, by the Restated Certificate of Incorporation or
Bylaws of the Company, or the qualification criteria of the Nasdaq National
Market), and the Securities when so issued, sold and delivered against payment
therefor in accordance with the provisions of this Agreement, and the Warrant
Shares issuable upon exercise of the Warrants, when issued upon such exercise,
will be duly and validly issued, fully paid and non-assessable and not subject
to preemptive or any other similar rights of the shareholders of the Company or
others and free, at time of issuance, of all restrictions on transfer subject to
restrictions on transfer imposed by applicable federal and state securities
laws.

     4.4 Authority for Agreement. The execution, delivery and performance by the
Company of this Agreement and each of the Collateral Agreements have been duly
authorized by all necessary corporate action, and this Agreement and each of the
Collateral Agreements have been duly executed and delivered and constitute valid
and binding obligations of the Company enforceable in accordance with their
respective terms, subject to bankruptcy or equitable laws that might affect the
enforceability of this Agreement and each of the Collateral Agreements. The
execution and delivery by the Company of this Agreement and each of the
Collateral Agreements, and the consummation by the Company of the 


                                       5

<PAGE>

transactions contemplated hereby and thereby (including, without limitation, the
issuance and sale of the Securities and the Warrant Shares), will not violate
any provision of law and will not conflict with or result in any breach of any
of the terms, conditions or provisions of, or constitute a default under, or
result in the creation of any lien, security interest, charge or encumbrance
upon any of the properties, assets or outstanding capital stock of the Company,
under the Company's Restated Certificate of Incorporation, or Bylaws, or any
indenture, lease, agreement or other instrument to which the Company is a party
or by which it or any of its properties is bound, or any decree, judgment,
order, statute, rule or regulation applicable to the Company.

     4.5 Governmental Consents. No consent, approval, order or authorization of,
or registration, qualification, designation, declaration or filing with, any
governmental or regulatory authority is required on the part of the Company in
connection with the execution and delivery of this Agreement and each of the
Collateral Agreements, and the consummation of the transactions contemplated
hereby and thereby (including, without limitation, the offer, issue, sale and
delivery of the Securities and the Warrant Shares issuable upon exercise of the
Warrants), except such filings as shall have been made or consents or approvals
obtained prior to and which shall be effective on and as of the Closing. Based

in part on the representations made by Buyer in Article V of this Agreement, the
offer and sale of the Securities to Buyer will be in compliance with applicable
federal and state securities laws.

     4.6 Litigation. Except as set forth in the Company SEC Reports, there are
no material actions, suits, proceedings or investigations, either at law or in
equity, or before any commission or other administrative authority in any United
States or foreign jurisdiction, of any kind now pending or, to the best of the
Company's knowledge, threatened or proposed involving the Company or any of its
properties or assets or which questions the validity or legality of the
transactions contemplated hereby, or to the Company's actual knowledge, against
its employees or consultants with respect to the Company's business.

     4.7 SEC Filings; Financial Statements. (a) The Company has filed all forms,
reports and documents required to be filed with the Commission since May 3, 1993
(collectively, the "Company SEC Reports"). The Company SEC Reports (i) were
prepared in all material respects in accordance with the requirements of the
Securities Act or the Exchange Act, as the case may be, and (ii) did not at the
time they were filed (or if amended or superseded by a filing prior to the date
of this Agreement, then on the date of such 


                                       6

<PAGE>

filing) contain any untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading.

     (b) Each of the financial statements (including, in each case, any related
notes thereto) contained in the Company SEC Reports was prepared in accordance
with generally accepted accounting principles applied on a consistent basis
throughout the periods involved (except as may be indicated in the notes
thereto), and each was complete and correct in all material respects and
presented fairly in all material respects presented the financial position of
the Company as at the respective dates thereof and the results of its operations
and cash flows for the periods indicated, except that the unaudited interim
financial statements were or are subject to normal and recurring year-end
adjustments which were not or are not expected to be material in amount.

     4.8 No Undisclosed Liabilities. The Company does not have any material
liabilities (absolute, accrued, contingent or otherwise) except liabilities (a)
in the aggregate adequately provided for in the Company's unaudited balance
sheet (including any related notes thereto) for the quarter ended March 31, 1996
included in the Company's Quarterly Report on Form 10-Q for the quarter year
ended March 31, 1996 (the "March 31, 1996 Balance Sheet"), or (b) incurred since
March 31, 1996 in the ordinary course of business.

     4.9 Absence of Changes. Since March 31, 1996, there has been no material
adverse change in the financial condition, business, or assets of the Company.

     4.10 Intellectual Property. (a) To the best of the Company's knowledge, it
has done nothing to compromise the secrecy, confidentiality or value of any of

its trade secrets, know-how, inventions, prototypes, designs, processes or
technical data required to conduct its business as now conducted or as proposed
to be conducted. The Company will continue to take reasonable security measures
in the future, as it presently is doing, to protect the secrecy,
confidentiality, and value of all of its trade secrets, know-how, inventions,
prototypes, designs, processes, and technical data important to the conduct of
its business.

     (b) Except as set forth in the Company SEC Reports, the Company has not
granted rights to manufacture, produce, license, market or sell its products to
any other Person and is not bound by any agreement that affects the Company's
exclusive right to develop, manufacture, distribute, market or sell its
products.


                                       7

<PAGE>

     4.11 No Defaults. The Company is not in default (a) under its Restated
Certificate of Incorporation or Bylaws, each as amended or restated to date, or
any indenture, mortgage, lease agreement, contract, purchase order or other
instrument to which it is a party or by which it or any of its property is bound
or affected or (b) with respect to any order, writ, injunction or decree of any
court of any federal, state, municipal or other governmental department,
commission, board, bureau, agency or instrumentality, domestic or foreign, which
defaults, either singly or in the aggregate, would have a material adverse
effect on the Company. At the time of the Closing, to the best knowledge of the
Company, there will exist no condition, event or act which constitutes, or which
after notice, lapse of time or both would constitute, a material default under
any of the foregoing which, either singly or in the aggregate, would have a
material adverse effect on the Company.

     4.12 Offerings. Except as contemplated by this Agreement or the Company's
1990 Amended and Restated Long-Term Incentive Plan or as otherwise disclosed by
the Company to Buyer, the Company does not have any current plans or intentions
to issue any shares of its capital stock or any other securities or any
securities convertible or exchangeable into shares of its capital stock or any
other securities.

     4.13 Brokers. No broker, finder or investment banker is entitled to any
brokerage, finder's or other fee or commission in connection with the
transactions contemplated by this Agreement based upon arrangements made by or
on behalf of the Company.

                                    ARTICLE V

                     REPRESENTATIONS AND WARRANTIES OF BUYER

     Buyer hereby represents and warrants to the Company as of the date hereof
as follows:

     5.1 Investment. Buyer is acquiring the Securities, and the Warrant Shares
into which the Warrants may be exercised, for its own account (and not for the
account of others) for investment and not with a view to, or for sale in

connection with, any distribution thereof, nor with any present intention of
distributing or selling the same; and, except as contemplated by this Agreement,
Buyer has no present or contemplated agreement, undertaking, arrangement,
obligation, indebtedness or commitment providing for the disposition thereof.


                                       8

<PAGE>

     5.2 Authority. Buyer has full power and authority to execute and deliver
and to perform this Agreement and each of the Collateral Agreements in
accordance with their respective terms. Buyer represents that it has not been
organized, reorganized or recapitalized specifically for the purpose of
investing in the Company.

     5.3 Accredited Investor. Buyer is an Accredited Investor within the
definition set forth in Securities Act Rule 501(a).

     5.4 Brokers. No broker, finder or investment banker is entitled to any
brokerage, finder's or other fee or commission in connection with the
transactions contemplated by this Agreement based upon arrangements made by or
on behalf of Buyer.

     5.5. Exchange Act Reports. So long as Buyer or an Affiliate of Buyer holds
any of the Securities, the Company shall, within two business days of filing,
give Buyer a copy of all periodic and other reports filed by the Company
pursuant to Section 13 of the Exchange Act.

                                   ARTICLE VI

                                 INDEMNIFICATION

     6.1 Survival of Representations, etc. All representations and warranties
contained herein shall survive the execution and delivery of this Agreement and
the Collateral Agreements and the closing of the transactions contemplated
hereby and thereby until the three-year anniversary of the Closing (or until
final resolution of any claim or action arising from the untruth, inaccuracy or
breach of any such representation and warranty, if notice of such untruth,
inaccuracy or breach was given prior to such third anniversary) without regard
to any investigation made by any of the parties hereto. All statements contained
in any certificate or other instrument delivered by the Company pursuant to this
Agreement and denominated as representations and warranties shall constitute
representations and warranties by the Company under this Agreement. All
agreements and covenants contained herein shall survive indefinitely until, by
their respective terms, they are no longer operative.

     6.2 Indemnification. The Company and Buyer shall, with respect to the
representations, warranties, covenants and agreements made by the Company or
Buyer, respectively, herein or in certificates or other instruments delivered in
connection therewith, indemnify, defend and hold the other


                                       9

<PAGE>


party harmless against all liability, together with all reasonable costs and
expenses related thereto (including legal and accounting fees and expenses),
arising from the untruth, inaccuracy or breach of any such representations,
warranties, covenants or agreements of the Company or Buyer, as the case may be.

                                   ARTICLE VII

                                  MISCELLANEOUS

     7.1 Legend. (a) Each certificate representing Shares sold pursuant to the
provisions hereof, if deemed advisable by the Company, shall bear the following
legend:

     THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
     UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED,
     SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
     SUCH SHARES ARE REGISTERED UNDER SUCH ACT OR AN OPINION OF COUNSEL
     REASONABLY SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT
     SUCH REGISTRATION IS NOT REQUIRED.

     (b) Buyer hereby agrees not to offer, sell or otherwise transfer the Shares
in violation of the foregoing legend.

     7.2 Assignment. Neither this Agreement nor any of the rights or obligations
hereunder may be assigned by the Company without the prior written consent of
Buyer, or by Buyer without the prior written consent of the Company, except that
Buyer may, without such consent, assign the right to acquire the Securities to a
wholly-owned subsidiary or subsidiaries of Buyer, each of which shall become
parties to this Agreement and each of the Collateral Agreements; provided,
however, that Buyer shall continue to be a party to this Agreement and to be
bound by the provisions hereof. Notwithstanding any contrary provisions of this
Section 7.2, following the Closing the Buyer may sell or otherwise transfer the
Securities as permitted in this Agreement and the Collateral Agreements. Subject
to the foregoing, this Agreement shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and assigns, and no other
Person shall have any right, benefit or obligation hereunder.

     7.3 Notices. Unless otherwise provided herein, any notice, request,
instruction or other document to be given hereunder by any party to the others
shall be in writing and delivered in person or by courier, telegraphed, telexed
or by facsimile transmission (with receipt confirmed) or mailed by certified
mail, postage prepaid, return receipt


                                       10

<PAGE>

requested (such mailed notice to be effective on the date of such receipt is
acknowledged), as follows:

                  If to the Company:

                           Regeneron Pharmaceuticals, Inc.

                           777 Old Saw Mill River Road
                           Tarrytown, New York 10591-6707
                           Attn: Corporate Secretary
                           Telecopy No.: (914) 345-7721

                  With a copy to:

                           Skadden, Arps, Slate, Meagher & Flom
                           919 Third Avenue
                           New York, New York  10022
                           Attn: Morris J. Kramer, Esq.
                           Telecopy No.: (212) 735-2000

                  If to Buyer:

                           Medtronic, Inc.
                           7000 Central Avenue NE
                           Minneapolis, Minnesota 55432
                           Attn: General Counsel
                           Telecopy No.: (612) 572-5459

                  and

                           Attn:  Vice President, Corporate
                           Development and Associate General
                           Counsel
                           Telecopy No.:  (612) 572-5404

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.

     7.4 Choice of Law. This Agreement shall be construed, interpreted and the
rights of the parties determined in accordance with the laws of the State of New
York except with respect to matters of law concerning the internal corporate
affairs of any corporate entity which is a party to or the subject of this
Agreement, and as to those matters the law of the jurisdiction under which the
respective entity derives its powers shall govern.

     7.5 Entire Agreement; Amendments and Waivers. This Agreement, together with
the Collateral Agreements, constitutes the entire agreement among the parties
pertaining to the subject matter hereof and thereof and supersedes all prior
agreements, understandings, negotiations and discussions, whether oral or
written, of the parties. No 


                                       11

<PAGE>

supplement, modification or waiver of this Agreement shall be binding unless
executed in writing by the party to be bound thereby. No waiver of any of the
provisions of this Agreement shall be deemed or shall constitute a waiver of any
other provision hereof (whether or not similar), nor shall such waiver
constitute a continuing waiver unless otherwise expressly provided.


     7.6 Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

     7.7 Invalidity. In the event that any one or more of the provisions
contained in this Agreement or in any other instrument referred to herein,
shall, for any reason, be held to be invalid, illegal or unenforceable in any
respect, such invalidity, illegality or unenforceability shall not affect any
other provision of this Agreement or any other such instrument.

     7.8 Headings. The headings of the Articles and Sections herein are inserted
for convenience of reference only and are not intended to be a part of or to
affect the meaning or interpretation of this Agreement.

     7.9 Expenses. Each of the Company and Buyer will each be liable for its own
costs and expenses incurred in connection with the negotiation, preparation,
execution and performance of this Agreement, provided that the Company will pay
all stamp or similar taxes which may be payable (i) in connection with the
execution and delivery of this Agreement and each of the Collateral Agreements
(and any amendments or modifications thereto), and (ii) in respect of the
issuance of the Securities (including the issuance of the Warrant Shares upon
exercise of the Warrants) to Buyer.

     7.10 Specific Enforcement. The Company and Buyer acknowledge and agree that
if any of the provisions of this Agreement were not performed in accordance with
their specific terms or were otherwise breached, irreparable damage would occur
and it would be extremely impracticable and difficult to measure damages.
Accordingly, in addition to any other rights and remedies to which the parties
may be entitled by law or equity, the parties shall be entitled to an injunction
or injunctions to prevent or cure breached of the provisions of this Agreement
and to enforce specifically the terms and provisions hereof, and the parties
expressly waive (i) the defense that a remedy in damages will be adequate and
(ii) any requirement, in an action for specific performance, for the posting of
a bond.


                                       12

<PAGE>

     7.11 Further Assurances. On and after the date hereof, the Company and
Buyer will take all appropriate action and execute all documents, instruments or
conveyances of any kind which may be reasonably necessary or advisable to carry
out any of the provisions hereof.

                           [Signature Page to follow]


                                       13

<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Agreement, or have
caused this Agreement to be duly executed on their respective behalf by their
respective officers thereunto duly authorized, as of the day and year first
above written.



                           REGENERON PHARMACEUTICALS, INC.


                           By:
                              -------------------------------
                           Name:  Leonard S. Schleifer
                           Title: President & Chief Executive Officer


                           MEDTRONIC, INC.


                           By:/s/ Michael D. Ellwein                        
                              ------------------------------                
                           Name:  Michael D. Ellwein
                           Title: Vice President Corporate
                           Development and Associate General
                           Counsel


                                       S1




<PAGE>

                                WARRANT AGREEMENT

                                 by and between

                         REGENERON PHARMACEUTICALS, INC.

                                       And

                                 MEDTRONIC, INC.

                            Dated as of June 27, 1996

<PAGE>

                                TABLE OF CONTENTS

SECTION 1.     Warrant Certificates.......................................     1
SECTION 2.     Execution of Warrant Certificates..........................     1
SECTION 3.     Registration...............................................     2
SECTION 4.     Registration of Transfers and Exchanges....................     2
SECTION 5.     Warrants...................................................     2
SECTION 6.     Payment of Taxes...........................................     5
SECTION 7.     Mutilated or Missing Warrant Certificates..................     5
SECTION 8.     Reservation of Warrant Shares..............................     5
SECTION 9.     Obtaining Stock Exchange Listings..........................     6
SECTION 10.    Adjustment of Exercise Price and Number of
Warrant Shares Issuable    ...............................................     6
     (a) Adjustment for Change in Capital Stock...........................     6
     (b) Adjustment for Other Distributions...............................     8
     (c) When De Minimis Adjustment May be Deferred.......................     8
     (d) When No Adjustment Required......................................     9
     (e) Notice of Adjustment.............................................     9
     (f) Voluntary Reduction..............................................     9
     (g) Reorganization of Company........................................    10
     (h) Company Determination Final......................................    11
     (i) When Issuance Or Payment May Be Deferred.........................    11
     (j) Adjustment in Number of Shares...................................    11
     (k) Form of Warrants.................................................    12
SECTION 11.    Fractional Interests.......................................    12
SECTION 12.    Notices to Warrant Holders.................................    12
SECTION 13.    Notices to Company and Warrant Holder......................    14
SECTION 14.    Supplements and Amendments.................................    15
SECTION 15.    Successors.................................................    15
SECTION 16.    Termination................................................    15
SECTION 17.    Governing Law .............................................    15
SECTION 18.    Benefits
 of This Agreement.................................    15
SECTION 19.    Counterparts...............................................    15
EXHIBIT A ................................................................    A1

<PAGE>

     THIS WARRANT AGREEMENT (the Agreement") is dated as of June 27, 1996 and
entered into by and between Regeneron Pharmaceuticals, Inc., a New York
corporation (the Company"), and Medtronic, Inc., a Minnesota Corporation 

(Medtronic").

     WHEREAS, the Company proposes to issue to Medtronic, or its designee,
Common Stock Purchase Warrants, as hereinafter described (the Warrants"), to
purchase up to an aggregate of 107,400 shares of Common Stock, $.001 par value
(the Common Stock"), of the Company (the Common Stock issuable on exercise of
the Warrants being referred to herein as the Warrant Shares"), pursuant to a
Stock and Warrant Purchase Agreement dated as of the date hereof (the Purchase
Agreement").

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereto agree as follows:

     SECTION 1.Warrant Certificates. The certificates evidencing the Warrants
(the Warrant Certificates") to be delivered pursuant to this Agreement shall be
in registered form only and shall be substantially in the form set forth in
Exhibit A attached hereto.

     SECTION 2. Execution of Warrant Certificates. Warrant Certificates shall be
signed on behalf of the Company by its Chairman of the Board or its President or
Vice President and by its Secretary or an Assistant Secretary under its
corporate seal. Each such signature upon the Warrant Certificates may be in the
form of a facsimile signature of the present or any future Chairman of the
Board, President, Vice President, Secretary or Assistant Secretary and may be
imprinted or otherwise reproduced on the Warrant Certificates and for that
purpose the Company may adopt and use the facsimile signature of any person who
shall have been Chairman of the Board, President, Vice President, Secretary or
Assistant Secretary, notwithstanding the fact that at the time the Warrant
Certificates shall be delivered or disposed of he shall have ceased to hold such
office. The seal of the Company may be in the form of a facsimile thereof and
may be impressed, affixed, imprinted or otherwise reproduced on the Warrant
Certificates.

     In case any officer of the Company who shall have signed any of the Warrant
Certificates shall cease to be such officer before the Warrant Certificates so
signed shall have been disposed of by the Company, such Warrant Certificates
nevertheless may be delivered or disposed of as though such person had not
ceased to be such officer of the Company; and any Warrant Certificate may be
signed on behalf of the Company by any person who, at the actual date of the
execution of such Warrant Certificate, shall be a proper officer of the Company
to sign such Warrant Certificate, although at the date of the 


                                       1

<PAGE>

execution of this Warrant Agreement any such person was not such officer.

     SECTION 3. Registration. The Company shall number and register the Warrant
Certificates in a register as they are issued.

     SECTION 4.Registration of Transfers and Exchanges. The Company shall from
time to time register the transfer of any outstanding Warrant Certificates in a
Warrant register to be maintained by the Company upon surrender of such Warrant

Certificates accompanied by a written instrument or instruments of transfer in
form satisfactory to the Company, duly executed by the registered holder or
holders thereof or by the duly appointed legal representative thereof or by a
duly authorized attorney. Upon any such registration of transfer, a new Warrant
Certificate shall be issued to the transferee (s) and the surrendered Warrant
Certificates shall be canceled and disposed of by the Company.

     The Warrant holders agree that each certificate representing Warrant Shares
will bear the following legend:

     THIS WARRANT AND THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE
     NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
     AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR
     HYPOTHECATED UNLESS AND UNTIL, IN THE CASE OF THE SHARES, SUCH
     SHARES ARE REGISTERED UNDER SUCH ACT OR, IN THE CASE OF THIS
     WARRANT AND THE SHARES, AN OPINION OF COUNSEL REASONABLY
     SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH
     REGISTRATION IS NOT REQUIRED.

     The Warrant holders further agree that they shall not offer, sell or
otherwise transfer the Warrant or Warrant Shares in violation of the foregoing
legend.

     Warrant Certificates may be exchanged at the option of the holder (s)
thereof, when surrendered to the Company at its office for another Warrant
Certificate or other Warrant Certificates of like tenor and representing in the
aggregate a like number of Warrants. Warrant Certificates surrendered for
exchange shall be canceled and disposed of by the Company.

     SECTION 5. Warrants; Exercise and Warrants. Subject to the terms of this
Agreement and compliance with any applicable law, each holder of Warrants shall
have the right, which may be exercised commencing at the opening of business on
June 27, 1996 and until 5:00 p.m., New York time on June 26, 2001, to receive
from the Company the number of fully paid and nonassessable Warrant Shares which
the holder may at the time be entitled to receive on exercise of such Warrants
and payment


                                       2

<PAGE>

to the Company of the Exercise Price (as defined below) then in effect for such
Warrant Shares. Each Warrant not exercised prior to 5:00 p.m., New York time, on
June 26, 2001 shall become void and all rights thereunder and all rights in
respect thereof under this Agreement shall cease as of such time.

     A Warrant may be exercised at any time or from time to time upon surrender
to the company at its office designated for such purpose (the address of which
is set forth in Section 13 hereof) of the certificate or certificates evidencing
the Warrants to be exercised with the form of election to purchase duly filled
in and signed, which signature shall be guaranteed by a bank or trust company
having an office or correspondent in the United States or a broker or dealer
which is a member of a registered securities exchange or the National
Association of Securities Dealers, Inc., and upon payment to the Company of the

exercise price (the Exercise price") which is set forth in the form of Warrant
Certificate attached hereto as Exhibit A, subject to adjustment pursuant to
Section 10, for the number of Warrant Shares in respect of which such Warrants
are then exercised. Payment of the aggregate Exercise Price shall be made in
cash or by certified or official bank check payable to the order of the Company.

     In lieu of exercising the Warrants for the cash Exercise Price provided for
in this Section 5 and pursuant to the other provisions of the Warrants, the
Warrants may be exercised by the holder by the surrender to the Company at its
office designated for such purpose (the address of which is set forth in Section
13 hereof) of the certificate or certificates evidencing the Warrants to be
exercised with the form of election to purchase duly filled in and signed, which
signature shall be guaranteed by a bank or trust company having an office or
correspondent in the United States or a broker or dealer which is a member of a
registered securities exchange or the National Association of Securities
Dealers, Inc., marked to reflect the non-cash exercise of Warrants and
specifying the number of Warrant Shares to be purchased. The Company agrees that
such Warrant Shares shall be deemed to be issued to the holder as the record
holder of such Warrant Shares as of the close of business on the date on which
this Warrant Certificate shall have been surrendered as aforesaid. Upon such
exercise, the holder shall be entitled to receive shares equal to the value of
the Warrants being exercised computed as of the date of surrender of this
Warrant Certificate to the Company using the following formula:


                                       3

<PAGE>

                     Y x (M-E)
                         -----
                X =        M

         where:

          X = the number of Warrant Shares to be issued to holder under this
paragraph.

          Y = the number of Warrant Shares otherwise purchasable under the
Warrants to be exercised at the date of such calculation.

          M = the Current Market Price per share of Common Stock at the date of
such calculation.

          E = the current Exercise Price.

     As used in this Agreement, the Current Market Price" per share of Common
Stock on any date is the average of the Quoted Prices of the Common Stock for 30
consecutive trading days commencing 45 trading days before the date in question.
The Quoted Price" of the Common Stock is the last reported sales price of the
Common Stock as reported by Nasdaq National Market, or if the Common Stock is
listed on a national securities exchange, the last reported sales price of the
Common Stock on such exchange (which shall be for consolidated trading if
applicable to such exchange), or if neither so reported or listed, the last
reported bid price of the Common Stock. In the absence of one or more such

quotations, the Board of Directors of the Company shall determine the Current
Market Price on the basis of such quotations as it in good faith considers
appropriate.

     Subject to the provisions of Section 6 hereof, upon such surrender of
Warrants and payment or other satisfaction of the Exercise Price, the Company
shall issue and cause to be delivered with all reasonable dispatch to or upon
the written order of the holder and in such name or names as the Warrant holder
may designate, a certificate or certificates for the number of full Warrant
Shares issuable upon the exercise of such Warrants together with cash as
provided in Section 11; provided, however, that if any reclassification,
consolidation, merger or lease or sale of assets is proposed to be effected by
the Company as described in subsection (1) of Section 10 hereof, or a tender
offer or an exchange offer for shares of Common Stock of the Company shall be
made, upon such surrender of Warrants and payment of the Exercise Price as
aforesaid, the Company shall, as soon as possible, but in any event not later
than two business days thereafter, issue and cause to be delivered the full
number of Warrant Shares issuable upon the exercise of such Warrants in the
manner described in this


                                       4

<PAGE>

sentence together with cash provided in Section 11. Such certificate or
certificates shall be deemed to have been issued and any person so designated to
be named therein shall be deemed to have become holder of record of such Warrant
Shares as of the date of the surrender of such Warrants and payment of the
Exercise Price.

     The Warrants shall be exercisable, at the election of the holders thereof,
either in full or from time to time in part and, in the event that a certificate
evidencing Warrants is exercised in respect of fewer than all of the Warrant
Shares issuable on such exercise at any time prior to the date of expiration of
the Warrants, a new certificate evidencing the remaining Warrant or Warrants
will be issued and delivered pursuant to the provisions of this Section and of
Section 2 hereof.

     All Warrant Certificates surrendered upon exercise of Warrants shall be
canceled and disposed of by the Company. The Company shall keep copies of this
Agreement and any notices given or received hereunder available for inspection
by the holders during normal business hours at its office.

     SECTION 6. Payment of Taxes. The Company will pay all documentary stamp
taxes, if any, attributable to the initial issuance of Warrant Shares upon the
exercise of Warrants.

     SECTION 7. Mutilated or Missing Warrant Certificates. In case any of the
Warrant Certificates shall be mutilated, lost, stolen or destroyed, the Company
may in its discretion issue, in exchange and substitution for and upon
cancellation of the mutilated Warrant Certificate, or in lieu of and
substitution for the Warrant Certificate lost, stolen or destroyed, a new
Warrant Certificate of like tenor and representing an equivalent number of
Warrants, but only upon receipt of evidence reasonably satisfactory to the

Company of such loss, theft or destruction of such Warrant Certificate and
indemnity, if requested, also reasonably satisfactory to it. Applicants for such
substitute Warrant Certificates shall also comply with such other reasonable
regulations and pay such other reasonable charges as the Company may prescribe.

     SECTION 8. Reservation of Warrant Shares. The Company will at all times
reserve and keep available, free from preemptive rights, out; of the aggregate
of its authorized but unissued Common Stock or its authorized and issued Common
Stock held in its treasury, for the purpose of enabling it to satisfy any
obligation to issue Warrant Shares upon exercise of the Warrants, the maximum
number of shares of Common Stock which may then be deliverable upon the exercise
of all the outstanding Warrants.


                                       5

<PAGE>

     The Company or, if appointed, the transfer agent for the Common stock (the
Transfer Agent") and every subsequent transfer agent for any shares of the
Company's capital stock issuable upon the exercise of any of the rights of
purchase aforesaid will be irrevocably authorized and directed at all times to
reserve such number of authorized shares as shall be required for such purpose.
The Company will keep a copy of this Agreement on file with the Transfer Agent
and with every subsequent transfer agent for any shares of the Company's capital
stock issuable upon the exercise of the rights of purchase represented by the
Warrants. The company will furnish such Transfer Agent a copy of all notices of
adjustments and certificates related thereto, transmitted to each holder
pursuant to Section 12 hereof.

     Before taking any action which would cause an adjustment pursuant to
Section 10 hereof to reduce the Exercise Price below the then par value (if any)
of the Warrant Shares, the Company will take any corporate action which may, in
the opinion of its counsel, be necessary in order that the Company may validly
and legally issue fully paid and nonassessable Warrant Shares at the Exercise
Price as so adjusted.

     The Company covenants that all Warrant Shares which may be issued upon
exercise of Warrants will, upon issue, be fully paid, nonassessable, free of
preemptive rights and free from all documentary stamp taxes, liens, charges and
security interests with respect to the issue thereof.

     SECTION 9. Obtaining Stock Exchange Listings. The Company will from time to
time take all action which may be necessary so that the Warrant Shares,
immediately upon their issuance upon the exercise of Warrants, will be listed on
the principal securities exchanges and markets within the United States of
America, if any, on which other shares of Common Stock are then listed.

     SECTION 10. Adjustment of Exercise Price and Number of Warrant Shares
Issuable. The Exercise Price and the number of Warrant Shares issuable upon the
exercise of each Warrant are subject to adjustment from time to time upon the
occurrence of the events enumerated in this Section 10. For purposes of this
Section 10, Common Stock" means shares now or hereafter authorized of any class
of common stock of the Company and any other stock of the Company, however
designated, that has the right (subject to any prior rights of any class or

series of preferred stock) to participate in any distribution of the assets or
earnings of the Company without limit as to per share amount, including, without
limitation, the Class A Common Stock, par value $.001, of the Company.

     (a) Adjustment for Change in Capital Stock.


                                       6

<PAGE>

     If the Company:

          1.   Pays a dividend or makes a distribution on its Common Stock in
               shares of its Common Stock;

          2.   Subdivides its outstanding shares of shares; or

          3.   Combines its outstanding shares of Common Stock into a smaller
               number of shares

then the Exercise Price in effect immediately prior to such action shall then be
adjusted in accordance with the formula:
                                               0
                                 E(1) =   E  x -
                                               A

     where:

           E(1)  = the adjusted Exercise Price

           E    = the current Exercise Price

           0    = the number of shares of Common Stock
           outstanding prior to such action

           A    = the number of shares of Common Stock
           outstanding immediately after such action

     In the case of a dividend or distribution the adjustment shall become
effective immediately after the record date for determination of holders of
shares of Common Stock entitled to receive such dividend or distribution, and in
the case of subdivision or combination, the adjustment shall become effective
immediately after the effective date of such corporate action.

     If after an adjustment a holder of a Warrant upon exercise of it may
receive shares of two or more classes or capital stock of the Company, the
Company shall determine the allocation of the adjusted Exercise Price between
the classes of capital stock. After such allocation, the exercise privilege, the
number of shares issuable upon such exercise, and the Exercise Price of each
class of capital stock shall thereafter be subject to adjustment on terms
comparable to those applicable to Common Stock in this Section 10.

     Such adjustment shall be made successively whenever any event listed above
shall occur.



                                       7

<PAGE>

     (b) Adjustment for Other Distributions.

     If the Company distributes to all holders of its Common Stock any of its
assets (including but not limited to securities and cash), debt securities,
capital stock, or any rights or warrants to purchase assets, debt securities,
capital stock. Or other securities of the Company, the Exercise Price shall be
adjusted in accordance with the formula:

                                        M - F
                           E(1) = E  x  -----
                                          M

     where:

           E(1) = the adjusted Exercise Price

           E   = the current Exercise Price

           M   = the current market price per share Common Stock on the
                 record date mentioned below

           F   = the fair market value on the record date of the
                 assets, capital stock or rights or warrants
                 applicable to one share of Common Stock. The
                 Board of Directors shall determine the fair
                 market value.

     The adjustment shall be made successively whenever any such distribution is
made and shall become effective immediately after the record date for the
determination of stockholders entitled to receive the distribution.

     This subsection does not apply to (i) dividends, distributions.
Combinations or issuances referred to in subsection (a) of this Section 10 or
(ii) nonextraordinary quarterly cash dividends distributed to all holders of
Common Stock.

     (c) When De Minimis Adjustment May be Deferred.

     No adjustment in the Exercise Price need be made unless the adjustment
would require an increase or decrease of at least 1% in the Exercise Price. Any
adjustments that are not made shall be carried forward and taken into account in
any subsequent adjustment.

     All calculations under this Section shall be made to the nearest cent or to
the nearest 1/100th of a share, as the case may be.


                                       8

<PAGE>


     (d) When no Adjustment Required.

     No adjustment need to be made for a transaction referred to in this Section
10 if Warrant holders are to participate in the transaction on a basis and with
notice that the Board of Directors determines to be fair and appropriate in
light of the basis and notice on which holders of Common Stock participate in
the transaction.

     No adjustment need be made for rights to purchase Common Stock pursuant to
a Company plan for reinvestment of dividends or interest.

     No adjustment need be made for a change in the par value or no par value of
the Common Stock.

     If the Company distributes or issues rights to all holders of its Common
Stock pursuant to be a shareholder rights plan, then no adjustment shall be made
pursuant to this Section 10 upon such distribution or issuance if, upon exercise
of the War rants, each holder thereof receives the same type and number of
unexpired rights it would have received (as adjusted for any event described in
Section 10 (a)) had it exercised its Warrants, and been a holder of the Warrant
Shares issuable upon exercise thereof, prior to the record date for such
distribution or issuance.

     To the extent Warrants become convertible into cash, no adjustment need be
made thereafter as to the cash. Interest will not accrue on the cash.

     (e) Notice of Adjustment.

     Whenever the Exercise Plan is adjusted, the Company shall provide the
notices required by Section 12 hereof.

     (f) Voluntary Reduction.

     The Company from time to time may reduce the Exercise Price by any amount
for any period of time if the period is at least 20 days and if the reduction is
irrevocable during the period; provided, however, that in no event may the
Exercise Price be less than par value or a share of Common Stock.

     Whenever the Exercise Price is reduced pursuant to subsection 10(f), the
Company shall mail to Warrant holders a notice of the reduction. The Company
shall mail the notice at least 15 days before the date the reduced Exercise
Price takes effect. The notice shall state the reduced Exercise Price and the
period it will be in effect.


                                       9

<PAGE>

     A reduction of the Exercise Price does not change or adjust the Exercise
Price otherwise in effect for purposes of subsections (a) or (b) of this Section
10.

     (g) Reorganization of Company.


     If any reclassification of the Common Stock of the Company or any
consolidation or merger of the Company with another entity, or the sale or lease
of all or substantially all of the Company's assets to another entity shall be
effected in such a way that holders of the Common Stock of the Company shall be
entitled to receive stock, securities or assets with respect to or in exchange
for such Common Stock, then, as a condition precedent to such reclassification,
consolidation, merger, sale or lease, lawful and adequate provisions shall be
made whereby the Warrant holder shall thereafter have the right to purchase and
receive upon the basis and the terms and conditions specified in this Agreement
and in lieu of the shares of Common Stock immediately theretofore purchasable
and receivable upon the exercise of the rights represented hereby, such shares
of stock, securities or assets as may be issue or payable in such
reclassification, consolidation, merger, sale or lease with respect to or in
exchange for the number of shares of Common Stock purchasable and receivable
upon the exercise of the rights represented hereby had such rights been
exercised immediately prior thereto, and in any such case appropriate provision
shall be made with respect to the rights and interests of the holders of the
Warrants to the end that the provisions hereof (including without limitation
provisions for adjustments of the Exercise Price and of the number of shares of
Common Stock purchasable and receivable upon the exercise of the Warrant) shall
thereafter be applicable, as nearly as may be, in relation to any shares of
stock, securities or assets thereafter deliverable upon the exercise hereof. The
Company will not effect any such reclassification, consolidation, merger, sale
or lease, unless prior to the consummation thereof the successor corporation (if
other than the Company) resulting from such reclassification, consolidation or
merger or the corporation purchasing or leasing such assets shall assume by a
supplemental Warrant Agreement, executed and mailed or delivered to the holders
of the Warrants at the last address thereof appearing on the books of Company,
the obligation to deliver to such holders such shares of stock, securities or
assets as, in accordance with the foregoing provisions, such holders may be
entitled to purchase.

     If the issuer of securities deliverable upon exercise of Warrants under the
supplemental Warrant Agreement is an affiliate of the formed, surviving,
transferee or lessee corporation, that issuer shall join in the supplemental
Warrant Agreement.


                                       10

<PAGE>

     If this subsection (g) applies, subsection (a) of this Section 10 does not
apply.

     (h) Company Determination Final.

     Any determination that the Company or the Board of Directors must make
pursuant to this Section 10 is conclusive.

     (i) When Issuance or Payment May be Deferred.

     In any case in which this Section 10 shall require than an adjustment in
the Exercise Price be made effective as of a record date for a specified event,

the Company may elect to defer until the occurrence of such event (i) issuing to
the holder of any Warrant exercised after such record date the Warrant Shares
and other capital stock of the Company, if any, issuable upon such exercise over
and above the Warrant Shares and other capital stock of the Company, if any,
issuable upon such exercise on the basis of the Exercise Price and (ii) paying
to such holder any amount in cash in lieu of a fractional share pursuant to
Section 11; provided, however, that the Company shall deliver to such holder a
due bill or other appropriate instrument evidencing such holder's right to
receive such additional Warrant Shares, other capital stock and cash upon the
occurrence of the event requiring such adjustment.

     (j) Adjustment in Number of Shares.

     Upon each adjustment of the Exercise Price pursuant to this Section 10,
each Warrant outstanding prior to the making of the adjustment in the Exercise
Price shall thereafter evidence the right to receive upon payment of the
adjusted Exercise Price that number of shares of Common Stock (calculated to the
nearest hundredth) obtained from the following formula:

                                       E
                        N(1) = N   x  ----
                                      E(1)

     where:

     N(1) = the adjusted number of Warrant Shares issuable upon exercise of a
Warrant by payment of the adjusted Exercise Price.

     N = the number of Warrant Shares previously issuable upon exercise of a
Warrant by payment of the Exercise Price prior to adjustment.

     E(1) = the adjusted Exercise Price.

     E = the Exercise Price prior to adjustment.


                                       11

<PAGE>

     (k) Form of Warrants.

     Irrespective of any adjustments in the Exercise Price or the number or kind
shares purchasable upon the exercise of the Warrants, Warrants theretofore or
thereafter issued may continue to express the same price and number and kind of
shares as are stated in the Warrants initially issuable pursuant to this
Agreement.

     SECTION 11. Fractional Interests. The Company shall not be required to
issue fractional Warrant Shares on the exercise of Warrants. If more than one
Warrant shall be presented for exercise in full at the same time by the same
holder, the number of full Warrant Shares which shall be issuable upon the
exercise thereof shall be computed on the basis of the aggregate number of
Warrant Shares purchasable on exercise of the Warrants so presented. If any
fraction of a Warrant Share would except for the provisions of this Section 11,

be issuable on the exercise of any Warrants (or specified portion thereof), the
Company shall pay an amount in cash equal to the Current Market Price on the day
immediately preceding the date the Warrant is presented for exercise, multiplied
by such fraction.

     SECTION 12. Notices to Warrant Holders. Upon any adjustment of the Exercise
Price pursuant to Section 10, the Company shall promptly thereafter (i) cause to
be filed with the Company a certificate by the Chief Financial Officer or Chief
Accounting Officer of the Company setting forth the Exercise Price after such
adjustment and setting forth in reasonable detail the method of calculation and
the facts upon which such calculations are based and setting forth the number of
Warrant Shares (or portion thereof) issuable after such adjustment in the
Exercise Price, upon exercise of a Warrant and payment of the adjusted Exercise
Price, which certificate shall be conclusive evidence of the correctness of the
matters set forth therein, and (ii) cause to be given to each of the registered
holders of the Warrant Certificates at his address appearing on the Warrant
register written notice of such adjustments by first-class mail, postage
prepaid. Where appropriate, such notice may be given in advance and included as
a part of the notice required to be mailed under the other provisions of this
Section 12.

     In case:

     (a) the Company shall authorize the issuance to all holders of shares of
Common Stock of rights, options or warrants to subscribe for or purchase shares
of Common Stock or of any other subscription rights or warrants; or


                                       12

<PAGE>

     (b) the Company shall authorize the distribution to all holders of shares
of Common Stock of evidences of its indebtedness or assets (other than cash
dividends or cash distributions payable out of earnings or earned surplus or
dividends or distributions payable in shares of Common Stock); or

     (c) of any consolidation or merger to which the Company is a party and for
which approval of any shareholders of the Company is required, or of the
conveyance or transfer of all or substantially all of the properties and assets
of the Company, or of any reclassification or change of Common Stock issuable
upon exercise of the Warrants (other than a change in par value, or from par
value to no par value, or from no par value to par value, or as a result of a
subdivision or combination), or a tender offer or exchange offer for shares of
Common Stock; or

     (d) of the voluntary or involuntary dissolution, liquidation or winding up
of the Company; or

     (e) the Company proposes to take any action that would require an
adjustment in the Exercise Price pursuant to subsections (a) or (b) of Section
10 and if the Company does not arrange for Warrant holders to participate
pursuant to subsection (d) of Section 10, or if the Company takes any action
that would require a supplemental Warrant Agreement pursuant to subsection (g)
of Section 10;


     Then the Company shall cause to be given to each of the registered holders
of the Warrant Certificates at his address appearing on the Warrant register, at
least 20 days (or 10 days in any case specified in clauses (a) or (b) above)
prior to the applicable record date hereinafter specified, or promptly in the
case of events for which there is no record date, by first-class mail, postage
prepaid, a written notice stating (i) the dates as of which the holders of
record of shares of Common Stock to be entitled to receive any such rights,
options, warrants or distribution are to be determined, or (ii) the initial
expiration date set forth in any tender offer or exchange offer for shares of
Common Stock, or (iii) the date on which any such consolidation, merger,
conveyance, transfer, dissolution, liquidation or winding up is expected to
become effective or consummated, and the date as of which it is expected that
holders or record of shares of Common Stock shall be entitled to exchange such
shares for securities or other property, if any, deliverable upon such
reclassification, consolidation, merger, conveyance, transfer, dissolution,
liquidation or winding up. The failure to give the notice required by this
Section 12 or any defect therein shall not affect the legality or validity or
any distribution, right, option, warrant, consolidation, merger, conveyance,
transfer, dissolution, liquidation or winding up, or the vote upon any action.


                                       13

<PAGE>

     Nothing contained in this Agreement or in any of the Warrant Certificates
shall be construed as conferring upon the holders thereof the right to vote or
to consent or to receive notice as shareholders in respect of the meetings of
shareholders or the election of Directors of the Company or any other matter, or
any rights whatsoever as shareholders of the Company.

     SECTION 13. Notices to Company and Warrant Holder. Unless otherwise
provided herein, any notice, request, instruction or other document to be given
hereunder by any party to the others shall be in writing and delivered in person
or by courier, telegraphed, telexed or by facsimile transmission (with receipt
confirmed), or mailed by certified mail, postage prepaid, return receipt
requested (such mailed notice to be effective on the date such receipt is
acknowledged), as follows:

     If to the Company:

          Regeneron Pharmaceuticals, Inc.
          777 Old Saw Mill River Road
          Tarrytown, New York 10591-6707
          Attn:  Corporate Secretary
          Telecopy No.:  (914) 345-7721

     With a copy to:

          Skadden, Arps, Slate, Meagher & Flom
          919 Third Avenue
          New York, New York 10022
          Attn:  Morris Kramer, Esq.
          Telecopy No.:  (212) 735-2000


     If to Warrant Holder:

          Medtronic, Inc.
          7000 Central Avenue NE
          Minneapolis, Minnesota 55432
          Attn:  General Counsel
          Telecopy No.:  (612) 572-5459

          and

          Attn:  Vice President, Corporate Development and
                 Associate General Counsel
          Telecopy No.:  (612) 572-5404

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.


                                       14

<PAGE>

     SECTION 14. Supplements and Amendments. The Company may not supplement or
amend this Agreement without the prior written approval of the majority of the
holders of Warrant Certificates affected by such supplement or amendment.

     SECTION 15. Successors. All the covenants and provisions of this Agreement
by or for the benefit of the Company shall bind and inure to the benefit of its
respective successors and assigns hereunder.

     SECTION 16. Termination. This Agreement shall terminate at 5:00 p.m., New
York time on June 26, 2001. Notwithstanding the foregoing, this Agreement will
terminate on any earlier date if all Warrants have been exercised.

     SECTION 17. Governing Law. This Agreement and each Warrant Certificate
issued hereunder shall be deemed to be a contract made under the laws of the
State of New York and for all purposes shall be construed in accordance with the
internal laws of said State.

     SECTION 18. Benefits of This Agreement. Nothing in this Agreement shall be
construed to give to any person or corporation other than the Company and the
registered holders of the Warrant Certificates any legal or equitable right,
remedy or claim under this Agreement; but this Agreement shall be for the sole
and exclusive benefit of the Company and the registered holders of the Warrant
Certificates.

     SECTION 19. Counterparts. This Agreement may be executed in any number of
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument.

                           [Signature Page to Follow]



                                       15

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, as of the day and year first above written.


                      REGENERON PHARMACEUTICALS, INC.

                      By:---------------------------------
                      Name:    Leonard S. Schleifer
                      Title:   President & Chief Executive Officer


                      Seal



                      Attest:----------------------------
                               Paul Lubetkin
                               Secretary


                      MEDTRONIC, INC.

                      By:/s/ Michael D. Ellwein
                         ---------------------------------
                      Name:    Michael D. Ellwein
                      Title:   Vice President Corporate
                               Development and Associate
                               General Counsel



                      Attest:/s/ Michael Kroll
                             ----------------------------
                               Assistant Secretary


                                       S1

<PAGE>

                                    EXHIBIT A

                          [Form of Warrant Certificate]

THIS WARRANT AND THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED,
SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL, WITH
RESPECT TO THE SHARES, SUCH SHARES ARE REGISTERED UNDER SUCH ACT OR, WITH
RESPECT TO THIS WARRANT OR THE SHARES, AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH REGISTRATION IS
NOT REQUIRED.


     EXERCISABLE ON OR BEFORE 5:00 P.M., NEW YORK TIME, JUNE 26, 2001

No.1                                               107,400 Warrants

                               Warrant Certificate

                         REGENERON PHARMACEUTICALS, INC.

     This Warrant Certificate certifies that Medtronic Asset Management, Inc.,
or registered assigns, is the registered holder of 107,400 Warrants expiring
June 26, 2001 (the "Warrants") to purchase Common Stock, $.001 par value (the
"Common Stock"), of Regeneron Pharmaceuticals, Inc., a New York corporation (the
"Company"). Each Warrant entitles the holder to receive from the Company upon
exercise on or before 5:00 p.m. New York Time on June 26, 2001, one fully paid
and nonassessable share of Common Stock (a "Warrant Share") at the initial
exercise price (the "Exercise Price") of $21.72 payable in lawful money of the
United States of America upon surrender of this Warrant Certificate and payment
of the Exercise Price at the office of the Company designated for such purpose,
subject to the holder's right to exercise such Warrants on a "cash-less" basis
pursuant to the Warrant Agreement referred to herein, and to the conditions set
forth herein and in the Warrant Agreement referred to herein. The Exercise Price
and number of Warrant Shares issuable upon exercise of the Warrants are subject
to adjustment upon the occurrence of certain events set forth in the Warrant
Agreement.

     No Warrant may be exercised after 5:00 p.m., New York Time on June 26,
2001, and to the extent not exercised by such time such Warrants shall become
void.


                                       A1

<PAGE>

     The Warrants evidenced by this Warrant Certificate are issued pursuant to a
Warrant Agreement dated as of June 27, 1996 (the "Warrant Agreement"), duly
executed and delivered by the Company, which Warrant Agreement is hereby
incorporated by reference in and made a part of this instrument and is hereby
referred to for a description of the rights, limitation of rights, obligations,
duties and immunities thereunder of the Company and the holders (the words
"holders" or "holder" meaning the registered holders or registered holder) of
the Warrants. A copy of the Warrant Agreement may be obtained by the holder
hereof upon written request to the Company.

     Warrants may be exercised at any time on or before 5:00 p.m., New York time
on June 26, 2001. The holder of Warrants evidenced by this Warrant Certificate
may exercise them by surrendering this Warrant Certificate, with the form of
election to purchase set forth hereon properly completed and executed, together
with payment of the Exercise Price at the office of the Company designated for
such purpose. In the event that upon any exercise of Warrants evidenced hereby
the number of Warrants exercised shall be less than the total number of Warrants
evidenced hereby, there shall be issued to the holder hereof or his assignee a
new Warrant Certificate evidencing the number of Warrants not exercised. No
adjustment shall be made for any dividends on any Common Stock issuable upon
exercise of this Warrant.


     The Warrant Agreement provides that upon the occurrence of certain events
the Exercise Price set forth on the face hereof may, subject to certain
conditions, be adjusted. If the Exercise Price is adjusted, the Warrant
Agreement provides that the number of shares of Common Stock issuable upon the
exercise of each Warrant shall be adjusted. No fractions of a share of Common
Stock will be issued upon the exercise of any Warrant, but the Company will pay
the cash value thereof determined as provided in the Warrant Agreement.

     Warrant Certificates, when surrendered at the office of the Company by the
registered holder thereof in person or by legal representative or attorney duly
authorized in writing, may be exchanged, in the manner and subject to the
limitations provided in the Warrant Agreement, but without payment of any
service charge, for another Warrant Certificate or Warrant Certificates of like
tenor evidencing in the aggregate a like number of Warrants.

     Upon due presentation for registration of transfer of this Warrant
Certificate at the office of the Company a new Warrant Certificate or Warrant
Certificates of like tenor and evidencing in the aggregate a like number of
Warrants shall be issued to the transferee(s) in exchange for this Warrant


                                       A2

<PAGE>

Certificate, subject to the limitations provided in the Warrant Agreement,
without charge except for any tax or other governmental charge imposed in
connection therewith.

     The Company may deem and treat the registered holder(s) thereof as the
absolute owner(s) of this Warrant Certificate (notwithstanding any notation of
ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof, of any distribution to the holder(s) hereof, and for all other
purposes, and the Company shall not be affected by any notice to the contrary.
Neither the Warrants nor this Warrant Certificate entitles any holder hereof to
any rights of a stockholder of the Company.

     This Warrant Certificate shall not be valid unless countersigned by the
Company, as such term is used in the Warrant Agreement.

     This Warrant Certificate shall not be offered, sold or otherwise
transferred in violation of the legend on the first page hereof

                           [Signature Page To Follow]


                                       A3

<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant Certificate to be
signed by its President and by its Secretary and has caused its corporate seal
to be affixed hereunto or imprinted hereon.

Dated:   June 27, 1996


                               REGENERON PHARMACEUTICALS, INC.



                               By:
                                  ------------------------------
                               Name:  Leonard S. Schleifer
                               Title: President & Chief Executive Officer



                               By:
                                  ------------------------------
                               Name:  Paul Lubetkin
                               Title: Secretary


                                       A4

<PAGE>

                         [Form of Election to Purchase]

                    (To be Executed Upon Exercise of Warrant)

     The undersigned hereby irrevocably elects (check applicable box):

     /__/ (i) to exercise the right, represented by this Warrant Certificate, to
receive _________ shares of Common Stock and herewith tenders payment for such
shares to the order of Regeneron Pharmaceuticals, Inc. in the amount of $_____
in accordance with the terms hereof.

     /__/ (ii) to convert __________ shares of Common Stock otherwise
purchasable upon exercise of the attached Warrant on a "cashless" basis into the
right to receive such lesser number of shares of Common Stock as determined by
Section 5 of the Warrant Agreement.

     The undersigned requests that a certificate for such shares be registered
in the name of ________________, whose address is
_______________________________ and that such shares be delivered to
________________ whose address is ___________________________
______________________________________. If said number of shares is less than
all of the shares of Common Stock purchasable hereunder, the undersigned
requests that a new Warrant Certificate representing the remaining balance of
such shares be registered in the name of ______________, whose address is
_________________________, and that such Warrant Certificate be delivered to
_________________, whose address is __________________.

                           Signature:____________________________________

                           Date: ________________________________________

                           Signature Guaranteed:_________________________



                                       A5




<PAGE>

                          REGISTRATION RIGHTS AGREEMENT

                                 by and between

                         REGENERON PHARMACEUTICALS, INC.
                               and MEDTRONIC, INC.

                            Dated as of June 27, 1996



<PAGE>

                               TABLE OF CONTENTS


1.  Introduction ........................................................    1
    1.1  Certain Definitions.............................................    1
    1.2  Sale or Transfer of Company's Common Stock......................    2
2.  Registration under Securities Act, etc...............................    2
    2.1  Incidental Registration.........................................    3
    2.2  Registration Procedures.........................................    3
    2.3  Allocation of Expenses..........................................    5
    2.4  Indemnification.................................................    5
    2.5  Information by Holder...........................................    8
    2.6  "Stand-off" Agreement...........................................    8
    2.7  Rule 144 Requirements...........................................    8
3.  Standstill Agreement.................................................    8
4.  Amendments and Waivers...............................................    10
5.  Notices .............................................................    10
6.  Successors and Assigns...............................................    11
7.  Transfer of Certain Rights...........................................    12
8.  Descriptive Headings.................................................    12
9.  Governing Law .......................................................    12
10. Counterparts ........................................................    12
11. Entire Agreement.....................................................    12
12. Submission to Jurisdiction...........................................    12
13. Severability ........................................................    13


                                       i

<PAGE>



                          REGISTRATION RIGHTS AGREEMENT


     REGISTRATION RIGHTS AGREEMENT, dated as of June 27, 1996, between Regeneron
Pharmaceuticals, Inc., a New York corporation (the "Company"), and Medtronic,
Inc., a Minnesota corporation (the "Purchaser").

     1. Introduction. The Company is a party to a Stock and Warrant Purchase

Agreement (the "Purchase Agreement"), dated June 27, 1996, with the Purchaser
and pursuant to which the Company has agreed, among other things, to issue
460,500 shares of its common stock, par
 value $.001 per share (the "Common
Stock"), and a warrant to purchase 107,400 shares of Common Stock (the
"Warrants") for an initial exercise price of $21.72 per share to the Purchaser.
This Agreement shall become effective upon the issuance of such securities to
the Purchaser or to a designated Affiliate of Purchaser pursuant to the Purchase
Agreement. Certain capitalized terms used in this Agreement are defined below;
references to Sections shall be to Sections of this Agreement. Terms not
otherwise defined herein shall have the meanings assigned to them in the
Purchase Agreement.

     1.1 Certain Definitions. As used in this Agreement, the following terms
shall have the following respective meanings:

     "Affiliate" means any corporation, company, partnership, joint venture or
other entity which controls, is controlled by, or is under common control with
Purchaser. For purposes of this definition control shall mean the direct or
indirect ownership of at least fifty (50%) percent or, if less than fifty (50%)
percent, the maximum percentage as allowed by applicable law of (a) the shares
of capital stock entitled to vote for the election of directors, or (b)
ownership interest.

     "Collaborative Study Agreement" means that certain Collaborative Study
Agreement, dated June 27, 1996 between the Company and Purchaser.

     "Registration Statement" means a registration statement filed by the
Company with the Commission for a public offering and sale of securities of the
Company (other than a registration statement on Form S-8 or Form S-4, or their
successor forms, or any other form for a limited purpose, or any registration
statement covering only securities proposed to be issued in exchange for
securities or assets of another corporation).


                                       1

<PAGE>

     "Registration Expenses" means the expenses described in subsection 2.3.

     "Registrable Shares" means (i) the Shares of Common Stock acquired by the
Purchaser pursuant to the Purchase Agreement and (ii) any other shares of Common
Stock of the Company issued in respect of such Shares (because of stock splits,
stock dividends, reclassifications, recapitalization, or similar event);
provided, however, that shares of Common Stock which are Registrable Shares
shall cease to be Registrable Shares upon any sale of such shares pursuant to a
Registration Statement, Section 4(1) of the Securities Act, or Rule 144 under
the Securities Act, or any sale in any manner to a person or entity which is not
entitled to the rights provided by this Agreement.

     1.2 Sale or Transfer of Company's Common Stock; Legend.

          (a) The Registrable Shares shall not be sold or transferred unless
either (i) they first shall have been registered under the Securities Act, or
(ii) the Company first shall have been furnished with an opinion of legal

counsel, reasonably satisfactory to the Company, to the effect that such sale or
transfer is exempt from the registration requirements of the Securities Act.

          (b) Notwithstanding the foregoing, no registration or opinion of
counsel shall be required for a transfer made in accordance with Rule 144 under
the Securities Act.

          (c) Each certificate representing the Registrable Shares shall bear a
legend substantially in the following form:

     THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
     THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED, SOLD OR
     OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL SUCH SHARES
     ARE REGISTERED UNDER SUCH ACT OR AN OPINION OF COUNSEL REASONABLY
     SATISFACTORY TO THE COMPANY IS OBTAINED TO THE EFFECT THAT SUCH
     REGISTRATION IS NOT REQUIRED.

     The foregoing legend shall be removed from the certificates representing
any Registrable Shares, at the request of the holder thereof, at such time as
such shares become eligible for resale pursuant to Rule 144(k) under the
Securities Act or such shares become publicly tradable pursuant to an effective
Registration Statement.

2. Registration under Securities Act, etc.


                                       2

<PAGE>

     2.1 Incidental Registration

          (a) Whenever the Company proposes to file a Registration Statement, at
any time and from time to time, it will, prior to such filing, give written
notice to the Purchaser of its intention to do so and, upon the written request
of the Purchaser given within ten (10) days after the Company provides such
notice (which request shall state the intended method of disposition of such
Registrable Shares), the Company shall use its best efforts in accordance with
the terms of this Registration Rights Agreement and law to cause all Registrable
Shares which the Company has been requested by the Purchaser to register to be
registered under the Securities Act to the extent necessary to permit their sale
or other disposition in accordance with the intended methods of distribution
specified in the request of the Purchaser; provided that the Company shall have
the right to postpone or withdraw any registration affected pursuant of this
subsection 2.1 without obligation to the Purchaser.

          (b) In connection with any offering under this subsection 2.1
involving an underwriting, the Company shall not be required to include any
Registrable Shares in such underwriting unless the Purchaser accepts the terms
of the underwriting as agreed upon between the Company and the underwriters, and
then only in such quantity as will not, in the opinion of the underwriters,
jeopardize the success of the offering by the Company. If in the opinion of the
managing underwriters the registration of all, or part of, the Registrable
Shares which the Purchaser has requested to be included would materially and
adversely affect such public offering then the Company shall be required to

include in the underwriting only that number of Registrable Shares, if any,
which the managing underwriter believes may be sold without causing such adverse
effect.

          (c) The Company may refuse to register shares eligible for sale under
Rule 144.

     2.2 Registration Procedures. If and whenever the Company is required by the
provisions of this Agreement to use its best efforts to effect the registration
of any of the Registrable Shares under the Securities Act, the Company shall:

          (a) prepare and file with the Commission, and use its reasonable best
efforts to cause the effectiveness of, any amendments and supplements to the
Registration Statement and the prospectus included in the Registration Statement
as may be necessary to comply with the provisions of the Securities Act;


                                       3

<PAGE>

          (b) furnish to the Purchaser such reasonable numbers of copies of the
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as the Purchaser
may reasonably request in order to facilitate the public sale or other
disposition of the Registrable Shares owned by the Purchaser;

          (c) use its best efforts to promptly register or qualify such
Registrable Securities under the securities laws of such states of the United
States as Purchaser reasonably requests (provided that the Company will not be
required to (i) qualify generally to do business in any jurisdiction where it
would not otherwise be required to qualify but for this subparagraph, (ii)
subject itself to taxation in any such jurisdiction, or (iii) consent to general
service of process in any such jurisdiction);

          (d) use its best efforts to cause all the Registrable Securities to be
listed on the Nasdaq National Market (or such other exchange or market upon
which the Company's common stock is then traded or listed);

          (e) permit the Purchaser, in its sole and exclusive judgment, to
participate in the preparation of such Registration Statement and to propose the
insertion therein of information, furnished to the Company in writing, which in
the reasonable judgment of the Purchaser and its counsel, and the Company and
its counsel, should be included;

          (f) in the event of the issuance of any stop order suspending the
effectiveness of a Registration Statement, or of any order suspending of
preventing the use of any related prospectus or suspending the qualification of
any common stock included in such Registration Statement for sale in any
jurisdiction; use its reasonable best efforts promptly to obtain the withdrawal
of such order; and

          (g) at the request of the Purchaser, furnish on the effective date of
such Registration Statement, an opinion, dated such date, of the counsel
representing the Company for the purpose of such registration, addressed to the

Purchaser, in which opinion such counsel shall stated that (i) such registration
became effective under the Securities Act, and (ii) to such counsel's knowledge,
no stop order suspending the effectiveness thereof has been issued and no
proceedings for that purpose have been instituted or are pending or contemplated
under the Securities Act.

     If the Company has delivered preliminary or final prospectuses to the
Purchaser and after having done so the prospectus is amended to comply with the
requirements of the Securities Act, the Company shall promptly notify the
Purchaser and, if requested, the Purchaser shall immediately


                                       4

<PAGE>

cease making offers of Registrable Shares and return all prospectuses to the
Company. The Company shall promptly provide the Purchaser with revised
prospectuses and, following receipt of the revised prospectuses, the Purchaser
shall be free to resume making offers of the Registrable Shares.

     In the event of an underwritten public offering, the Company shall enter
into and perform its obligations under an underwriting agreement, in usual and
customary form, with the managing underwriter of such offering. The Purchaser
shall also enter into and perform its obligations under such agreement.

     2.3 Allocation of Expenses. The Company will pay, and indemnify and hold
the Purchaser harmless for the payment of, all Registration Expenses of all
registrations under this Agreement, except as set forth in this Agreement. The
term Registration Expenses shall mean all expenses incurred by the Company in
complying with this Section 2, including, without limitation, all registration
and filing fees, exchange listing fees, printing expenses, and other fees; and
disbursements of counsel for the Company, state Blue Sky fees and expenses
(except that the Purchaser shall not cause or request the filing for Blue Sky
approval in any state reasonably refused by the Company), and the expenses of
any special audits incident to or required by any such registration, but
excluding underwriting discounts and selling commissions.

     Each seller of the Registrable Shares shall pay all discounts, commissions,
fees, and expenses of the underwriters, selling brokers, dealer managers and
similar industry professionals relating to the distribution of its Registrable
Shares and all other expenses (including without limitation fees of attorneys,
accountants or others retained by such seller of Registrable Shares) not
specifically otherwise described in this Section 2.3.

     2.4 Indemnification. In the event of any registration of any of the
Registrable Shares under the Securities Act pursuant to this Agreement, the
Company will indemnify and hold harmless the Purchaser, and each of its officers
and directors, and each other person, if any, who controls the Purchaser, within
the meaning of the Securities Act or the Exchange Act against any losses,
claims, damages or liabilities, joint or several, to which the Purchaser or
controlling person may become subject under the Securities Act, the Exchange
Act, state securities or Blue Sky laws or otherwise, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of or
are based upon any untrue statement or alleged untrue statement of any material

fact contained in any Registration 


                                       5

<PAGE>

Statement under which such Registrable Shares were registered under the
Securities Act, any preliminary prospectus or final prospectus contained in the
Registration Statement, or any amendment or supplement to such Registration
Statement, or arise out of or are based upon the omission or alleged omission to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading or arise out of or are based upon any
violation by the Company of the Securities Act in connection with such
registration; and the Company will reimburse the Purchaser, officer, director,
and each such controlling person for any legal or any other expenses reasonably
incurred by the Purchaser, officer, director, or controlling person in
connection with the investigating or defending of any such loss, claim, damage,
liability or action; provided, however, that the Company will not be liable in
any such case to the extent that any such loss, claim, damage or liability
arises out of or is based upon any untrue statement or omission made in such
Registration Statement, preliminary prospectus or final prospectus, or any such
amendment or supplement, in reliance upon and in conformity with information
furnished to the Company, in writing, by or on behalf of the Purchaser, officer,
director, underwriter or controlling person specifically for use in the
preparation thereof.

     In the event of any registration of any of the Registrable Shares under the
Securities Act pursuant to this Agreement, the Purchaser will indemnify and hold
harmless the Company, each of its directors and officers and each underwriter
(if any) and each person, if any, who controls the Company or any such
underwriter within the meaning of the Securities Act or the Exchange Act,
against any losses, claims, damages or liabilities, joint or several, to which
the Company, such directors and officers, underwriter or controlling person may
become subject under the Securities Act, Exchange Act, state securities or Blue
Sky laws or otherwise, insofar as such losses, claims, damages or liabilities
(or actions in respect thereof) arise out of or are based upon any untrue
statement or alleged untrue statement of a material fact contained in any
Registration Statement under which such Registrable Shares were registered under
the Securities Act, any preliminary prospectus or final prospectus contained in
the Registration Statement, or arise out of or are based upon any omission or
alleged omission to state a material fact required to be stated therein or
necessary to make the statements therein not misleading, if the statement or
omission was made in reliance upon and in conformity with information furnished
in writing to the Company, by or on behalf of the Purchaser, specifically for
use in connection with the preparation of such Registration Statement,
prospectus, amendment or supplement; provided, however, that the obligations of
the Purchaser hereunder shall be limited to an amount equal to the proceeds of
the Registrable Shares sold as contemplated herein; provided, 


                                       6

<PAGE>

further, that, with respect to any untrue statement or omission or alleged

untrue statement or omission made in any preliminary prospectus, the indemnity
agreement contained in this subsection 2.4 shall not apply to the extent that
any loss, claim, damage or liability results from the fact that a current copy
of the prospectus was not sent or given to the person asserting any such loss,
claim, damage or liability at or prior to the written confirmation of the sale
of the Registrable Shares confirmed to such person if it is determined that it
was the responsibility of the Company, any of its directors, officers or agents
to provide such person with a current copy of the prospectus and such current
copy of the prospectus would have cured the defect giving rise to such loss,
claim, damage or liability.

     Each party entitled to indemnification under this subsection 2.4 (the
"Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom; provided, that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not be unreasonably
withheld); and, provided, further that the failure of any Indemnified Party to
give notice as provided herein shall not relieve the Indemnifying Party of its
obligations under this subsection 2.4. The Indemnified Party may participate in
such defense at such party's expense provided, however, that the Indemnifying
Party shall pay such expense if representation of such Indemnified Party by the
counsel retained by the Indemnifying Party would be inappropriate due to actual
or potential differing interests between the Indemnified Party and any other
party represented by such counsel in such proceeding. No Indemnifying Party, in
the defense of any such claim or litigation, shall except with the consent of
each Indemnified Party, consent to entry of any judgment or enter into any
settlement which does not include as an unconditional term thereof the giving by
the claimant or plaintiff to such Indemnified Party of a release from all
liability in respect of such claim or litigation, and no Indemnified Party shall
consent to entry of any judgment or settle such claim or litigation without the
prior written consent of the Indemnifying Party.

     If the indemnification provided for in this subsection 2.4 is held by a
court of competent jurisdiction to be unavailable to an Indemnified Party, then
each Indemnifying Party, in lieu of indemnifying such Indemnified Party
thereunder, hereby agrees to contribute to the amount paid or payable by such
Indemnified Party in such proportion as is appropriate to reflect the relative
fault of the Indemnifying Party on the one hand and of the Indemnified Party on
the


                                       7

<PAGE>

other. Notwithstanding the foregoing, the amount the Purchaser shall be obliged
to contribute pursuant to this paragraph of subsection 2.4 shall be limited to
an amount equal to the public offering sale price of the shares sold by the
Purchaser.

     2.5 Information by Holder. The Purchaser shall furnish to the Company such
information regarding the Purchaser and the distribution proposed by the

Purchaser as the Company may request in writing and as shall be required in
connection with any registration, qualification or compliance referred to in
this Section 2.

     2.6 "Stand-off" Agreement. The Purchaser, if requested by the Company and
an underwriter of Common Stock or other securities of the Company, shall agree
not to sell or otherwise transfer or dispose of any Registrable Shares for a
specified period of time (not to exceed 120 days) following the effective date
of the Registration Statement. Such agreement shall be in writing in a form
satisfactory to the Company and such underwriter. The Company may impose stop
transfer instructions with respect to the Registrable Shares or other securities
subject to the foregoing restrictions until the end of the stand-off period.

     2.7 Rule 144 Requirements. The Company agrees to use reasonable efforts to:

          (a) make and keep public information available, as those terms are
understood and defined in Rule 144 under the Securities Act;

          (b) file with the Commission in a timely manner all reports and other
documents required of the Company under the Securities Act and the Exchange Act;
and

          (c) furnish to the Purchaser upon request a copy of the most recent
annual or quarterly report of the Company, and such other reports and documents
of the Company as the Purchaser may reasonably request to avail itself of any
similar rule or regulation of the Commission allowing it to sell all or any
portion of the Registrable Shares without registration.

3. Standstill Agreement.

     3.1 Except as hereinafter set forth in subsection 3.2, the Purchaser
agrees, for itself and its Affiliates, whether now or hereafter created or
acquired, and any of the Purchaser's pension plans or employee benefit plan
programs sponsored by the Purchaser for which the Purchaser controls its
investment decisions, that it will not, until the later of (x) the termination
of the Collaboration Agreement or (y) 


                                       8

<PAGE>

five (5) years from the date of this Agreement, without the prior written
consent of the Company;

               (i) directly or indirectly acquire or own beneficially and/or of
record more than twenty (20) percent of the Then Outstanding Capital Stock of
the Company (as hereinafter defined). For purposes of this Section 3, the "Then
Outstanding Capital Stock" of the Company shall be deemed to be all of the then
issued and outstanding shares of the Common Stock and all shares of Common Stock
into which the then outstanding shares of preferred stock and any other
convertible securities or any options or warrants issued by the Company are then
convertible or exercisable, as well as all capital stock issued as a result of
any stock split, stock dividend or reclassifications of Common Stock
distributable, on a pro rata basis, to all holders of Common Stock or securities

convertible into Capital Stock;

               (ii) directly or indirectly, solicit proxies or consents or
become a participant in a solicitation (as such terms are defined in Regulation
14A under the Exchange Act) in opposition to the recommendation of the majority
of the Board of Directors of the Company with respect to any matter, or seek to
advise or influence any person, with respect to the voting of any securities of
the Company or any of its subsidiaries;

               (iii) propose or induce any other person to propose, directly or
indirectly, (x) any merger or business combination involving the Company or any
of its subsidiaries, (y) the purchase or sale of any assets of the Company or
any of its subsidiaries or (z) the purchase of any of the voting securities of
the Company, by tender offer or otherwise (except pursuant to the exercise of
rights, warrants, options or similar securities distributed by the Company to
holders of voting securities generally);

               (iv) deposit any voting securities in a voting trust or subject
any voting securities to any arrangement or agreement with respect to the voting
of voting securities; or

               (v) advise, assist or encourage any other person in connection
with any of the foregoing.

     3.2 The Purchaser will be relieved of the restrictions set forth in
subsection 3.1 of this Agreement only under the following circumstances and for
the specific transactions as set forth herein below:

               (i) if a third party, not an Affiliate of the Purchaser, directly
or indirectly makes a bona fide tender offer or other bona fide offer for more
than twenty (20%) percent but not more than fifty (50%) percent of the Company's
Then Outstanding Capital Stock, and said third 


                                       9

<PAGE>

party has, in the reasonable opinion of the Purchaser, the financial resources,
ability and intention to carry out such offer, the Purchaser shall not be
prohibited from purchasing or conducting a tender offer for an amount of shares
equal to the amount of shares sought to be acquired by the third party during
the period of its tender offer;

               (ii) if a third party, not an Affiliate of the Purchaser,
directly or indirectly makes a bona fide tender offer or other bona fide offer
for more than fifty (50%) percent of the Company's Then Outstanding Capital
Stock and said third party has, in the reasonable opinion of the Purchaser, the
financial resources, ability and intention to carry out such offer, the
Purchaser shall not be prohibited from purchasing or conducting a tender offer
for all or less than all of the Then Outstanding Capital Stock it does not
already own during the period of the third party's tender offer; or

               (iii) in the event the Company hereafter issues to a third party
more than seven (7%) percent of its Then Outstanding Capital Stock pursuant to a

negotiated written transaction without requiring such third party to enter into
a standstill agreement with provisions substantially as restrictive as those set
forth in this Section 3, then Purchaser shall be relieved from its obligations
hereunder.

     3.3 The parties hereto acknowledge and agree that the Company would be
irreparably damaged in the event that any of the provisions of this Section 3
are not performed in accordance with their specific terms or are otherwise
breached and that monetary damages are not an adequate remedy for said breach.
It is accordingly, agreed that the Company shall be entitled to injunctive
relief to prevent breaches of this Section 3 by Purchaser and/or its Affiliates,
and to specifically enforce this Section 3 and the terms and provisions thereof,
in addition to any other remedy to which such aggrieved party may be entitled,
at law or in equity, in any court of competent jurisdiction in the State of New
York, and that for this purpose, Purchaser, for itself and its Affiliates,
hereby consents to the jurisdiction of such courts. The Company may enter a stop
transfer order with respect to the transfer of voting securities except in
compliance with the termination of this Agreement.

     4. Amendments and Waivers. This Agreement may be amended, modified,
supplemented or waived only with the written consent of the parties hereto.

     5. Notices. Unless otherwise provided herein, any notice, request,
instruction or other document to be given hereunder by any party to the others
shall be in writing and delivered in person or by courier, telegraphed,


                                       10

<PAGE>

telexed or by facsimile transmission (with receipt confirmed) or mailed by
certified mail, postage prepaid, return receipt requested (such mailed notice to
be effective on the date of such receipt is acknowledged), as follows:

          If to the Company:

               Regeneron Pharmaceuticals, Inc.
               777 Old Saw Mill River Road
               Tarrytown, New York 10591-6707
                Attn: Corporate Secretary
                Telecopy No.: (914) 345-7721

          With a copy to:

                Skadden, Arps, Slate, Meagher & Flom
                919 Third Avenue
                New York, New York  10022
                Attn: Morris J. Kramer, Esq.
                Telecopy No.: (212) 735-2000

          If to Buyer:

                Medtronic, Inc.
                7000 Central Avenue NE

                Minneapolis, Minnesota 55432
                Attn: General Counsel
                Telecopy No.: (612) 572-5459

          and

                Attn:  Vice President, Corporate Development
                       and Associate General Counsel
                Telecopy No.:  (612) 572-5404

or to such other place and with such other copies as either party may designate
as to itself by written notice to the others.

     6. Successors and Assigns. The provisions of this Agreement, including the
rights and obligations hereunder, shall be binding upon, and inure to the
benefit of, the respective successors and assigns of the Purchaser (the
Transferees) and of the Company, provided that such Transferees shall be an
Affiliate of the Purchaser, and such Transferees shall become the Purchaser for
the all purposes of this Agreement. If such Transferee(s) is not an Affiliate of
the Purchaser, the rights granted to Purchaser under section 2 of this Agreement
shall not be transferable and will not inure to the benefit of such
non-Affiliate Transferee.


                                       11

<PAGE>

     7. Transfer of Certain Rights.

          (a) The rights and obligations of the Purchaser under this Agreement
may be transferred by the Purchaser to any Affiliate of the Purchaser, provided,
however, that the rights and obligations of the Purchaser under section 2 of
this Agreement may not be transferred to any third party other than any
Affiliate of the Purchaser. The Company shall be given written notice by the
Purchaser at the time of such transfer stating the name and address of the
Transferee and identifying the securities with respect to which such rights are
assigned.

          (b) Any Transferee to whom rights are transferred shall, as a
condition to such transfer, deliver to the Company a written instrument pursuant
to which the Transferee agrees to be bound by the obligations imposed upon the
Purchaser hereunder to the same extent as if such Transferee were the Purchaser
hereunder.

     8. Descriptive Headings. The headings of the Articles and Sections herein
are inserted for convenience of reference only and are not intended to be a part
of or to affect the meaning or interpretation of this Agreement.

     9. Governing Law. THIS AGREEMENT SHALL BE CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, AND THE RIGHTS OF THE PARTIES SHALL BE GOVERNED BY, THE LAWS OF
THE STATE OF NEW YORK WITHOUT REFERENCE TO THE PRINCIPLES OF CONFLICTS OF LAWS.

     10. Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which

together shall constitute one and the same instrument.

     11. Entire Agreement; Amendments and Waivers. This Agreement, together with
the Collateral Agreements, constitutes the entire agreement among the parties
pertaining to the subject matter hereof and thereof and supersedes all prior
agreements, understandings, negotiations and discussions, whether oral or
written, of the parties. No supplement, modification or waiver of this Agreement
shall be binding unless executed in writing by the party to be bound thereby. No
waiver of any of the provisions of this Agreement shall be deemed or shall
constitute a waiver of any other provision hereof (whether or not similar), nor
shall such waiver constitute a continuing waiver unless otherwise expressly
provided.

     12. Submission to Jurisdiction. Any legal action or proceeding with respect
to this Agreement may be brought in the courts of the State of New York or of
the United States of America for the Southern District of New York, and, by


                                       12

<PAGE>

execution and delivery of this Agreement, each of the parties hereby accepts for
itself and in respect of its property, generally and unconditionally, the
jurisdiction of the aforesaid courts and appellate courts from any thereof. Each
party hereto hereby irrevocably consents to the service of process out of any of
the aforementioned courts in any action or proceeding by the mailing of copies
thereof to such party by registered or certified mail, postage prepaid, return
receipt requested, to such party at its address specified in Section 5.

     13. Severability. If any provision of this Agreement, or the application of
such provisions to any Person or circumstance, shall be held invalid, the
remainder of this Agreement, or the application of such provision to Persons or
circumstances other than those to which it is held invalid, shall not be
affected thereby.

     IN WITNESS WHEREOF, the parties have caused this Agreement to be executed
and delivered by their respective officers thereunto duly authorized as of the
date first above written.


Dated:  June 27, 1996

                                    REGENERON PHARMACEUTICALS, INC.


                                    By
                                      -----------------------------

Dated:  June 27, 1996

                                    MEDTRONIC, INC.


                                    By /s/ Michael D. Ellwein

                                       ----------------------------



                                       13




<PAGE>
                      ASSIGNMENT AND ASSUMPTION AGREEMENT

      THIS ASSIGNMENT AND ASSUMPTION AGREEMENT is made and entered into as of
June 27, 1996, by and between Medtronic, Inc., a Minnesota corporation
("Medtronic"), Medtronic Asset Management, Inc., a Minnesota corporation and
wholly-owned subsidiary of Medtronic ("MAM"), and Regeneron Pharmaceuticals,
Inc., a New York corporation ("Regeneron").

                                    RECITALS:

      A. Medtronic and Regeneron are parties to a Stock and Warrant Purchase
Agreement, a Registration Rights Agreement, and Warrant Agreement, each dated
June 27, 1996 (collectively, the "Agreements") pursuant to which Medtronic or
its assignee will purchase Regeneron stock and warrants from Regeneron and
receive certain registration rights with respect to such stock.

      B. Medtronic desires to assign and delegate to MAM, and MAM desires to
assume Medtronic's rights and obligations pursuant to the "Agreements".

      NOW, THEREFORE, in consideration of the foregoing and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledge, the parties agree as follows:

                                   AGREEMENTS:

      1. Assignment and Delegation. Medtronic hereby transfers, assigns, and
delegates to MAM all of Medtronic's rights and obligations under
 and pursuant to
the Agreements, including but not limited to Medtronic's right and obligation to
purchase the Regeneron stock and warrants contemplated therein, effective as of
the date hereof.

      2. Assumption. MAM hereby assumes and agrees to perform all of the
obligations of Medtronic under and pursuant to the Agreements, including but not
limited to Medtronic's right and obligation to purchase the Regeneron stock and
warrants contemplated therein.

      3. Acknowledgment: Regeneron acknowledges and agrees to the foregoing
assignment and delegation of Medtronic's rights and obligations under the
Agreement to MAM and MAM's assumption of such obligations.


                                      -1-

<PAGE>

      IN WITNESS WHEREOF, the parties have executed this Assignment and
Assumption Agreement as of the date first above written.




                                    MEDTRONIC, Inc.

                                    By:   /s/ Michael D. Ellwein

                                          -------------------------------------
                                          Michael D. Ellwein, Vice President
                                          Corporate Development and Associate
                                          General Counsel



                                    MEDTRONIC ASSET MANAGEMENT, INC.


                                    By:   /s/ Michael D. Ellwein
                                          -------------------------------------
                                          Michael D. Ellwein, Vice President




                                    REGENERON PHARMACEUTICALS, INC.


                                    By:______________________________________

                                    Its:_____________________________________


                                      -2-




<PAGE>

                                                              Exhibit 11
REGENERON PHARMACEUTICALS, INC.
STATEMENT OF COMPUTATION OF NET LOSS PER SHARE


<TABLE>
<CAPTION>
                                                       Three months ended June 30,           Six months ended June 30,
                                                         1996               1995               1996             1995
                                                         ----               ----               ----             ----
<S>                                                  <C>                <C>                <C>                <C>
Primary:

Net loss                                             ($7,624,633)       ($4,380,899)       ($15,392,131)      ($8,551,300)
                                                     ===========        ===========        ============       ===========
Per share data
  Weighted average number of Class A and
    Common shares outstanding during the period       24,585,518         19,487,627          23,296,691        19,406,248 
                                                     ===========        ===========        ============       ===========
    Net loss per share                                    ($0.31)            ($0.22)             ($0.66)           ($0.44)
                                                     ===========        ===========        ============       ===========
Fully diluted:

Net loss                                             ($7,624,633)       ($4,380,899)       ($15,392,131)      ($8,551,300)
                                                     ===========        ===========        ============       ===========
Per share data
  Weighted average number of Class A and
    Common shares outstanding during the period       24,585,518         19,487,627          23,296,691        19,406,248 

  Shares issuable upon exercise of options
    and warrants                                       3,607,408          2,236,158           3,336,165         2,070,063 

  Shares assumed to be repurchased under
    the treasury stock method                         (1,776,186)        (1,066,485)         (1,507,453)         (958,311)
                                                     -----------        -----------        ------------       -----------
                                                      26,416,740         20,657,300          25,125,403        20,518,000 
                                                     ===========        ===========        ============       ===========
    Net loss per share                                    ($0.29)            ($0.21)             ($0.61)           ($0.42)
                                                     ===========        ===========        ============       ===========

</TABLE>


                                     -144-






<TABLE> <S> <C>


<ARTICLE> 5
       
<S>                           <C>
<PERIOD-TYPE>                 6-MOS
<FISCAL-YEAR-END>             DEC-31-1996
<PERIOD-START>                JAN-01-1996
<PERIOD-END>                  JUN-30-1996
<CASH>                        48,850,085
<SECURITIES>                  47,482,506
<RECEIVABLES>                 6,404,189
<ALLOWANCES>                  0
<INVENTORY>                   0
<CURRENT-ASSETS>              81,677,628
<PP&E>                        50,114,320
<DEPRECIATION>                16,777,650
<TOTAL-ASSETS>                139,272,190
<CURRENT-LIABILITIES>         9,602,342
<BONDS>                       0
<PREFERRED-MANDATORY>         0
<PREFERRED>                   0
<COMMON>                      25,614
<OTHER-SE>                    112,775,034
<TOTAL-LIABILITY-AND-EQUITY>  139,272,190
<SALES>                       0
<TOTAL-REVENUES>              11,346,831
<CGS>                         0
<TOTAL-COSTS>                 0
<OTHER-EXPENSES>              26,260,904
<LOSS-PROVISION>              0
<INTEREST-EXPENSE>            478,058
<INCOME-PRETAX>               (15,392,131)
<INCOME-TAX>                  0
<INCOME-CONTINUING>           (15,392,131)
<DISCONTINUED>                0
<EXTRAORDINARY>               0
<CHANGES>                     0
<NET-INCOME>                  (15,392,131)
<EPS-PRIMARY>                 (0.66)
<EPS-DILUTED>                 0
        


</TABLE>