Exhibit 10.3 

As of November 14, 2008

Leonard S. Schleifer, M.D., Ph.D.

President and Chief Executive Officer, 
Regeneron Pharmaceuticals, Inc.

777 Old Saw Mill River Road 
Tarrytown, New York 10591-6707

Dear Len:

     This
employment agreement will replace and update the agreement dated December 20,
2002 between Regeneron Pharmaceuticals, Inc. ("Regeneron" or the "Company") and
you. The compensation obligations of the Company under this agreement (the
"Agreement") will be reduced by any amounts actually paid by any affiliate,
subsidiary, and related entity controlled by or under common control with the
Company ("Related Entity").

	1.	      	Employment.
	 
	 		(a)	      	You will continue to
      serve, during the Employment Term, as President and Chief Executive
      Officer of the Company with the customary responsibilities and authority
      of such positions and in accordance with the Company's By-Laws. You will
      report directly and only to the Board of Directors. If elected, you will
      also continue to serve as a Director of the Company. The Company shall
      during the Employment Term recommend and propose you as a Director of the
      Company and any Related Entity and, if the Chairman of the Board of
      Directors as of the date hereof at any time ceases to serve as such, as
      Chairman of the Board of Directors. To the extent you are not elected
      Chief Executive Officer of any Related Entity, such Chief Executive
      Officer shall report to you.
	  
	 		(b)		During the Employment
      Term, you shall devote substantially all of your business time and
      attention to the performance of your duties for the Company and serve the
      Company diligently and to the best of your ability. You may, however,
      perform teaching, consulting, patient care, and other activities as you
      have done from time to time in the past, provided that they do not
      materially conflict with the performance of your duties to the Company. In
      addition, you may manage your personal investments and be involved in
      civic and charitable activities so long as such activities do not
      materially interfere with your providing services hereunder. During the
      Employment Term, you shall not serve as a member of a board of directors
      of any other for-profit corporation (other than a Related Entity) without
      the prior written consent of the Board of Directors (which consent shall
      not be unreasonably withheld). In no event will the provisions of this
      Agreement in any way modify, alter, reduce, or limit the fiduciary
      obligations you owe to the Company as an officer and Director of the
      Company.
	  
	2.		Term. Except for earlier
      termination as provided in paragraph 4 hereof, your employment under this
      Agreement (the "Employment Term") is for an initial term that commenced on
      February 12, 1998 and ended on December 31, 2003 (the "Initial Term") and
      automatically extended since then. Unless notice is given of an intent not
      to extend the Initial Term or any extension thereof, by you or by the
      Company by written notice at least ninety (90) days prior to each December
      31 during the Employment Term, the Employment Term shall be deemed as of
      such 90th day to have been extended and continue until the end of the
      following calendar year unless otherwise terminated as provided in
      paragraph 4 hereof.


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	3.	      	Compensation/Benefits.
	 
	 		(a)	      	During the Employment
      Term, you have received base salary at an annual rate of not less than
      $575,000, paid currently at periodic intervals in accordance with the
      Company's payroll practices for salaried employees. Adjustments in your
      base salary during the term of this Agreement (which shall thereafter be
      your "Base Salary") have been and may be effected from time to time upon
      the recommendation of the Compensation Committee and the approval of the
      Board of Directors based upon an annual review by the Compensation
      Committee, but your Base Salary, once increased, shall in no event be
      decreased; provided, however, that in the event there is a general
      reduction of compensation applicable to senior executives generally,
      nothing herein shall preclude the Board of Director's ability to reduce
      your Base Salary consistent with this reduction. You shall also
      participate in and be the beneficiary of any cash bonus payments, stock
      option and other equity programs, incentive programs, pension plans,
      profit sharing plans and other benefit programs and fringe benefit
      programs implemented by the Company and otherwise available to executive
      officers, nonindependent directors, and employees of the Company, at a
      level commensurate with your position, in accordance with the terms and
      conditions of such programs.
	 
	 		(b)		You have separately
      entered into one or more stock purchase agreements and stock option award
      agreements with the Company. With the sole exception of the provisions in
      this Agreement regarding vesting and exercisability of stock options,
      nothing in this Agreement will affect any term or provision of any stock
      purchase or stock option award agreement you have entered into or will
      enter into with the Company under any stock purchase or incentive plan of
      the Company and the stock options to purchase common shares previously
      granted to you shall remain outstanding, and in effect, in accordance with
      their respective terms.
	 
	 		(c)		The Company will
      during the Employment Term maintain insurance on your life in the amount
      of $1,000,000 payable to such beneficiary as you designate. You may change
      the designated beneficiary of this policy at any time. The Company will
      not borrow against or otherwise encumber the policy or proceeds thereof.
      The Company will also during the Employment Term maintain for your benefit
      a long term disability policy that will pay you at least 65 percent of
      your Base Salary during such period as you are unable, for physical or
      mental reasons, to perform the responsibilities of your current position,
      with such benefits commencing no later than six (6) months after
      incurrence of the disability.


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	        	(d)	      	During the Employment Term,
      subject to paragraph 14(o)(i), the Company will pay for or will reimburse
      the reasonable costs of your medical malpractice insurance and all
      customary, ordinary, and necessary business expenses incurred by you in
      the performance of your duties (including expenses related to equipment
      you customarily and normally use in connection with the performance of
      your duties to the Company), provided that you present such vouchers,
      receipts, or other documentation as are required by the regular procedures
      of the Company for the reimbursement of such expenses. In addition, during
      the Employment Term, the Company will pay you a monthly automobile cash
      allowance of $1,500 plus all expenses of maintaining and operating your
      automobile in accordance with current policy.
		 
		(e)		You shall be entitled to at least
      four (4) weeks of vacation per year, which vacation may be taken at such
      times as you elect with due regard to the needs of the
  Company.
		 
		(f)		Subject to paragraph 14(o)(i),
      the Company will pay, or will reimburse the reasonable costs of any legal,
      accounting or other professional services you incur in connection with
      your tax preparation and financial planning to an annual maximum of (i)
      the amount for financial planning and similar benefits generally made
      available to other senior executives of the Company for such year, plus
      (ii) $12,500 per year (together, the “Maximum Annual Professional Services
      Reimbursement Amount”), including, without limitation, a tax gross-up
      reimbursement, so long as the total direct reimbursement and tax gross-up
      reimbursement is no more than the Maximum Annual Professional Services
      Reimbursement Amount per year. For calendar years commencing after
      December 31, 2004, any accrued unused amount that would have been
      reimbursed under this paragraph 3(f) during such year will be forfeited to
      the extent reimbursable expenses are not incurred during the applicable
      year. For calendar years prior to 2004, any unused amounts under the
      annual reimbursable cap (the "Grandfathered Reimbursements") under this
      Agreement and the February 12, 1998 agreement between you and the Company
      shall continue to be available to you for reimbursement of legal,
      accounting or other professional service expenses (and tax gross ups) you
      incur in connection with your tax preparation and financial planning under
      the terms of this Section 3(f). For the avoidance of doubt, all
      reimbursements shall first be deemed to come from the annual allowance
      that, if unused, is subject to forfeiture.
		 
		(g)		During the Employment Term (and,
      subject to the terms of this paragraph, thereafter), the Company will
      continue to designate you as its nominee at the club at which you are
      currently designated as the nominee of the Company (the "Club") and,
      subject to paragraph 14(o)(i), pay any dues or other expenses incurred
      with regard to your use of the Club. After your termination of employment
      with the Company, you shall, at your election made to the Company within
      45 days thereafter: (i) elect not to be designated by the Company as the
      nominee for the Company's Club membership; (ii) if permitted by the Club,
      have the Company transfer the Company's Club membership to you, with the
      Company having its bond either returned or assumed by you (in which case
      you would pay the Club any dues or other Club expenses incurred thereafter
      and, if you assumed the bond, would pay the Company the amount of the
      bond); or (iii) have the Company continue your designation as nominee for
      the Company's Club membership (in which case you would pay the dues and
      other Club expenses incurred thereafter and deposit the amount of the Club
      bond with the Company, with such amount (as adjusted in the same manner as
      the bond) returned to you by the Company at the earlier of such time as it
      receives a refund of the bond or you elect to cease being designated as
      the Company's nominee at the Club). Notwithstanding anything else herein,
      this obligation shall survive any termination of your employment with the
      Company.


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	 		(h)		Following any
      termination of your employment with the Company, if and to the extent the
      Company maintains any health benefit plans (and without any obligation to
      do so), you and your (and, after your death, your wife's) dependents shall
      be entitled to continue to participate therein by paying an amount equal
      to the COBRA cost thereof for the remainder of your life and that of your
      spouse at the time of such termination of employment. Notwithstanding
      anything else herein, this provision shall survive any termination of your
      employment with the Company.
	 
	4.	      	Termination. Except as otherwise
      provided in paragraph 2, the Employment Term shall end upon the earliest
      of the following to occur:
	 
	 		(a)	     	Your
  death.
	 
	 		(b)		Upon a vote of the
      Board of Directors and notice to you of termination as a result of your
      Permanent Disability. Permanent Disability means your inability, by reason
      of any physical or mental impairment, to substantially perform the
      significant aspects of your regular duties as contemplated by this
      Agreement and which inability is reasonably contemplated to continue for
      at least one (1) year from its incurrence and at least ninety (90) days
      from the date of such vote. Any question as to the existence, extent, or
      potentiality of your Permanent Disability shall be determined by a
      qualified independent physician selected by you (or, if you are unable to
      make such selection, by an adult member of your immediate family), and
      reasonably acceptable to the Company. Such physician's written
      determination of your Permanent Disability shall, upon delivery to the
      Company, be final and conclusive for purposes of this Agreement; provided,
      however, that no such determination shall be final and conclusive with
      respect to any disability coverage under paragraph 3(c).
	 
	 		(c)		Your Involuntary
      Termination, as set forth in paragraph 6 below.
	 
	 		(d)		Your Removal for
      Cause, as set forth in paragraph 7(a) below.
	 
	 		(e)		Your voluntary
      termination (other than termination on account of death, Permanent
      Disability or termination by you for Good Reason) upon ninety (90) days
      prior written notice; provided, however, that the Company may waive such
      notice requirement in a written waiver delivered to
  you.


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	5.	      	Death and
      Disability.
	 
	 		(a)	      	If the Employment Term
      terminates by reason of your death or your Permanent Disability as
      provided in paragraph 4, then, except as provided in this paragraph 5(a),
      no further compensation will become payable to you under this Agreement,
      other than any earned but unpaid Base Salary, earned but unpaid bonuses,
      the pro rata portion of incentive compensation earned for services
      rendered through the date of your death or Permanent Disability, any
      deferred compensation and all other payments, benefits or fringe benefits
      to which you may be entitled under the terms of any applicable
      compensation arrangement or benefit, equity or fringe benefit plan or
      program or grant (other than any severance plan) or this Agreement
      (collectively, "Entitlements"). Entitlements shall be calculated and paid
      as set forth in paragraph 5(c) below. You shall also be entitled to the
      Stock Option Treatment (as set forth in paragraph 8(f) below). In the
      event of your termination on account of your Permanent Disability, the
      Company shall pay you 100% of your Base Salary which you would have
      received during the eighteen (18) month period following your date of
      termination, such payment to be made in lump sum on the sixtieth (60th)
      day following termination, reduced by the projected amount of disability
      payments you are expected to receive during such period, calculated at the
      time of your termination, and assuming your continuous disability for the
      full (18) month period, and the Company shall also (i) continue to provide
      for insurance and other payments that are to be made under disability
      policies or plans paid for or maintained by the Company, (ii) continue to
      provide life insurance at a level of coverage comparable to the coverage
      in effect for you at the time of your termination on account of Permanent
      Disability, and (iii) pay you a monthly amount equal to COBRA premiums for
      medical and dental coverage as set forth in subparagraph (b) below, in
      each case upon the same terms and conditions (except for the requirement
      of your continued employment) for a period of eighteen (18) months
      following your date of termination.
	 
	 		(b)		With respect to
      monthly amount for medical and dental coverage provided under paragraph
      5(a), you shall be required to pay the applicable COBRA premium for you
      and your dependents, or to obtain coverage for you and your dependents
      under substitute arrangements, and you shall be paid a monthly amount by
      the Company equal to such amount, and to the extent you incur tax that you
      would not have incurred as an active employee as a result of the
      aforementioned coverage, you shall receive from the Company an additional
      gross-up payment in the amount necessary, subject to paragraph 14(o)(i),
      so that you will have no additional cost for receiving such items or any
      additional payment.
	 
	 		(c)		Earned but unpaid
      bonus shall mean any declared but unpaid bonus for any prior bonus period
      and, if the bonus for the current bonus period is other than totally
      discretionary, a pro rata portion of the calculated bonus for the bonus
      period based on days in the bonus period prior to termination of your
      services compared to total days in the bonus period. Any incentive
      compensation shall be deemed earned and shall be paid based on actual
      results during the measuring period and a pro rata measurement of the days
      in the incentive period prior to termination of your services compared to
      total days in the incentive period. Such pro rata bonus and incentive
      compensation shall be paid to you at the same time and form that bonuses
      and incentive compensation are paid to other active participants. Any
      deferred compensation shall be paid in accordance with the terms of the
      applicable plan. Base Salary shall be paid in accordance with normal
      payroll practice.


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	6.	      	Involuntary Termination.
	 
	 		(a)	      	Involuntary
      Termination shall mean either your termination by the Company in
      accordance with paragraph 6(b) hereof, or your resignation in accordance
      with paragraph 6(c) hereof.
	 
	 		(b)		Termination By The
      Company Without Cause: Your termination
      by the Company shall be considered to be "without cause" if (i) you are
      terminated or dismissed, for reasons other than your death, Permanent
      Disability or "Removal for Cause," as President or Chief Executive
      Officer, unless you have previously consented in writing to such removal
      or dismissal (which consent may be given or withheld in your sole
      discretion); provided, however, that your termination or dismissal as
      President shall not be a Termination by the Company without Cause if the
      person appointed President reports to you, or (ii) prior to your
      sixty-fifth (65th) birthday, the Company gives notice of nonextension of
      the Employment Term pursuant to paragraph 2 hereof.
	 
	 		(c)		Termination By You
      For Good Reason: Your resignation shall
      be considered to be for Good Reason if you resign as President and Chief
      Executive Officer (whether or not you resign as a Director and, if
      Chairman of the Board, as Chairman of the Board) upon ninety (90) days'
      prior written notice within ninety (90) days after the occurrence of one
      of the following events: (i) your removal, dismissal or failure to be
      re-elected as President or Chief Executive Officer (other than on account
      of your termination for some other reason) or a de jure or de facto
      material reduction in your duties, title, responsibilities, authority,
      status, or reporting responsibilities (other than in connection with the
      appointment of a Chief Operating Officer or President who reports to you),
      unless you have previously consented in writing to such removal, dismissal
      or reduction (which consent may be given or withheld in your sole
      discretion); (ii) the failure to elect you, or your removal, dismissal or
      failure to be re-elected, as Chairman of the Board if the current Chairman
      of the Board ceases to serve as such; (iii) the failure of the Company to
      pay to you any amount due under this Agreement within ten (10) days after
      the later of its due date or your written demand for payment of such
      amount; (iv) any material breach by the Company of any provision of this
      Agreement which is not cured within thirty (30) days after your giving of
      written notice of such breach to the Company; (v) one year after a Change
      of Control, as defined in Exhibit A hereto, to the extent you are employed
      hereunder at that time; (vi) the relocation of the Company's principal
      executive office more than fifty (50) miles from the current location; or
      (vii) the failure of the Company to obtain and deliver to you a reasonably
      satisfactory written agreement from any successor to the Company as
      provided in paragraph 14(l).


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	 		(d)		Upon an
      Involuntary Termination, you will become entitled to the benefits
      specified in paragraph 8 of this Agreement. In addition, you will be
      entitled to your Entitlements as calculated and paid in accordance with
      paragraph 5(c) above.
	 
	7.	      	Removal
      for Cause.
	 
	 		(a)	     	Removal for
      Cause shall mean the termination of your duties as President, Chief
      Executive Officer and, if you are then serving in such capacity, Chairman
      of the Board, effected by the Board of Directors of the Company (after a
      Board of Directors meeting for which you had at least ten (10) days prior
      written notice and at which you had the opportunity to have counsel
      present to represent you in connection with issues concerning your removal
      for cause) by reason of any one or more of the following, which
      individually or in the aggregate has a material adverse effect on the
      aggregate business or affairs of the Company and any Related
    Entity:
	 
	 		 		(i)	     	your gross neglect of
      your duties, your willful and continuing refusal to perform your duties
      (other than, in any such case, because of a reasonably documented mental
      or physical illness), your refusal to obey any lawful order of the Board
      of Directors, or any material breach by you of any provision of paragraphs
      11 or 12 of this Agreement, which, in any of the foregoing events,
      continues for more than thirty (30) days following your receipt of written
      notice from the Board of Directors that describes such breach or other
      event
	 
	 		 		(ii)		your willful
      misconduct with respect to the business or affairs of the Company or of
      any Related Entity
	 
	 		 		(iii)		your conviction of, or
      your plea of nolo contendere to, a misdemeanor involving embezzlement or
      fraud or other offense involving money or other property of the Company
      (other than a good faith dispute over expense account items), any criminal
      violation of the Securities Act of 1933 or the Securities Exchange Act of
      1934, or any felony, provided your rights of appeal with respect to such
      matter have either lapsed or been exercised
	 
	 		(b)		Upon your
      Removal for Cause, you will be entitled to your Entitlements as calculated
      and paid in accordance with paragraph 5(c) above. In such case, no amounts
      will be payable to you under paragraph 8 of this Agreement for any reason
      whatsoever.
	 
	 		(c)		In the event
      of your voluntary termination in accordance with paragraph 4(e), you shall
      receive the same amounts as if you were Removed for Cause plus the Stock
      Option Treatment (as set forth in paragraph
8(f)).


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	8.		Severance
      Benefits.
							 
			(a)		Subject to paragraphs
      8(b) and 8(e), upon an Involuntary Termination, you will become entitled
      to the following severance benefits:
							 
	   		 		(i)	     	The Company will pay
      you an amount equal to one and one-quarter (1-1/4) times the sum of (x)
      your Base Salary in effect (or, if improperly reduced, required to be in
      effect) at the time of your Involuntary Termination and (y) the average of
      the annual bonuses paid or payable to you during the three (3) completed
      fiscal years prior to your Involuntary Termination; and such payment shall
      made to you in lump sum on the date specified in paragraph 8(g)
      below.
	 
	 		 		(ii)		With respect to
      medical and dental coverage, you shall be required to pay the applicable
      COBRA premium for you and your dependents, or to obtain covering for you
      and your dependents under substitute arrangements, for eighteen (18)
      months, and you shall be reimbursed monthly by the Company for such
      amount, and to the extent you incur tax that you would not have incurred
      as an active employee as a result of the aforementioned coverage, you
      shall receive from the Company, subject to paragraph 14(o)(i), an
      additional gross-up payment in the amount necessary so that you will have
      no additional cost for receiving such items or any additional payment. The
      Company shall continue to provide you and your eligible dependents, upon
      the same terms and conditions (except for the requirement of your
      continued employment), with life insurance at a level of coverage
      comparable to the coverage in effect for you at the time of your
      Involuntary Termination for the eighteen (18) month period following your
      Involuntary Termination.
							 
		     	(b)	     	Notwithstanding
      paragraph 8(a), upon your Involuntary Termination within three (3) years
      after a Change of Control, as defined in Exhibit A hereto, or within three
      (3) months prior thereto in anticipation of a Change of Control, you will
      become entitled to the following severance benefits in lieu of the amounts
      under paragraph 8(a) above:
							 
					(i)		The Company will make a lump sum
      payment to you at on the date specified in paragraph 8(g) below of an
      amount equal to three (3) times the sum of (x) your Base Salary in effect
      (or, if improperly reduced, required to be in effect) at the time of your
      Involuntary Termination and (y) the average of the annual bonuses paid or
      payable to you during the three (3) completed fiscal years prior to your
      Involuntary Termination or, if higher, the three (3) completed fiscal
      years prior to the Change of Control.
							 
					(ii)		Any bonus, vacation pay or other
      compensation accrued or earned under law or in accordance with the
      Company's policies applicable to you but not yet paid and any incurred but
      unreimbursed business expenses for the period prior to termination shall
      be payable, subject to paragraph 14(o)(i), in accordance with the
      Company's policies and the terms of the applicable
  plan


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					(iii)		With respect to medical and
      dental coverage, you shall be required to pay the applicable COBRA premium
      for you and your dependents, or to obtain covering for you and your
      dependents under substitute arrangements, for the thirty-six (36) month
      period following your Involuntary Termination, and you shall be reimbursed
      monthly by the Company for such amount, and to the extent you incur tax
      that you would not have incurred as an active employee as a result of the
      aforementioned coverage, you shall receive from the Company, subject to
      paragraph 14(o)(i), an additional gross-up payment in the amount necessary
      so that you will have no additional cost for receiving such items or any
      additional payment. The Company shall continue to provide you and your
      eligible dependents, upon the same terms and conditions (except for the
      requirement of your continued employment), with life insurance at a level
      of coverage comparable to the coverage in effect for you at the time of
      your Involuntary Termination for the thirty-six (36) month period
      following your Involuntary Termination.
							 
	   	     	 	     	(iv)	     	All stock options,
      whether heretofore or hereafter, granted to you shall become fully vested
      and immediately exercisable and, if the basis were an action in
      anticipation of the Change of Control, the option shall remain exercisable
      (unless the original terms would otherwise end) at least through the
      Change of Control
			 
			(c)		Each of your
      outstanding loans from the Company will become due and payable in
      accordance with their existing terms and provisions, and none of these
      loans will be forgiven or otherwise canceled in whole or in
  part.
			 
			(d)		The Company
      agrees that if your employment with the Company is terminated during the
      Employment Term for any reason whatsoever, you are not required to seek
      other employment or to attempt in any way to reduce any amounts payable to
      you by the Company pursuant to this Agreement. Further, the amount of any
      payment or benefit provided for in this Agreement shall not be reduced by
      any compensation earned by you or benefit provided to you as the result of
      employment by another employer or otherwise. In addition, the amounts
      payable hereunder shall not be subject to setoff, counterclaim,
      recoupment, defense or other right which the Company may have against you
      or others, except upon obtaining by the Company of a final nonappealable
      judgment against you.
			 
			(e)		In the event
      that you have received or commenced receipt of any payments or other
      rights under paragraphs 5(a) or 8(a), you shall not be entitled to any
      additional payments or rights under paragraphs 5(a), 8(a), or 8(b) with
      respect to any subsequent occurrence which might otherwise give rise to
      such payments or rights under such paragraphs, except as specifically
      provided with regard to paragraph 8(b).
			 
			(f)		Notwithstanding anything to the contrary in this Agreement or any
      other agreement between you and the Company, the Company agrees that if
      your employment with the Company terminates during the Employment Term for
      any reason (other than a Removal for Cause), including a termination of
      employment pursuant to paragraphs 4(a), 4(b), 4(c) and 4(e), (i) all of
      your stock options and other equity awards shall continue to vest in
      accordance with the terms of the applicable grant agreement
      notwithstanding the employment termination, (ii) you (or your executors or
      administrators of your estate, in the case of your death) shall be
      entitled to exercise any of your stock options at any time during the
      original term of such options, and (iii) all agreements relating to your
      stock options or other equity shall be deemed amended to the extent
      inconsistent with the foregoing (such continued vesting and
      exercisability, the "Stock Option Treatment").


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	 		(g)	      	Any amounts payable
      and benefits or additional rights provided pursuant to paragraphs 8(a) or
      8(b) beyond Entitlements ("Release Conditioned Amounts") shall be payable
      only if you deliver to the Company a release of all claims that you have
      or may have (and you do not revoke the release within the revocation
      period) within sixty (60) days after your termination in a form
      substantially in the form of Exhibit B hereto. Release Conditioned Amounts
      shall be paid to you in a lump sum, or shall commence if in installments,
      on the sixtieth (60th) day following your date of termination, with any
      missed installment payments paid in a lump sum on such date.
	 
	9.	     	Excise
      Tax. In the event that you become
      entitled to payments and/or benefits which would constitute "parachute
      payments" within the meaning of Section 280G(b)(2) of the Internal Revenue
      Code of 1986, as amended, (the "Code"), the provisions of Exhibit C shall
      apply.
	 
	10.		Proprietary Information and Inventions. You understand and acknowledge that:
	 
	 		(a)		The Company is and
      will be engaged in a continuous program of research, design, development,
      production, and marketing with respect to its business.
	 
	 		(b)		Your employment by the
      Company creates a relationship of confidence and trust between the Company
      and you with respect to certain information relating to the business and
      affairs of the Company or applicable to the business of any client,
      customer, consultant, partner, external collaborator, or service provider
      of the Company, which may be made known to you by the Company or by any
      client, customer, consultant, partner, external collaborator, or service
      provider of the Company, or learned by you during the period of your
      affiliation with the Company.
	 
	 		(c)		The Company will
      possess information created, discovered, or developed by, or otherwise
      become known to, the Company (including, without limitation, information
      created, discovered, developed, or made known to you during the Employment
      Term) or in which property rights have been or may be assigned or
      otherwise conveyed to the Company (whether or not the information has
      commercial value in the business in which the Company is or proposes to be
      engaged) and is treated by the Company as confidential. All this
      information is "Proprietary Information," which includes, but is not
      limited to, systems, processes, formulae, data, functional specifications,
      computer software, programs and displays, know-how, improvements,
      discoveries, inventions, developments, designs, techniques, marketing
      plans, strategies, forecasts, new and proposed products, unpublished
      financial statements, budgets, projections, licenses, prices, costs, and
      customer, external collaborator, partner, client, and supplier lists, and
      any and all intellectual properties. The foregoing, however, shall not
      cover information generally known in the industry or which hereafter
      become generally known in the industry.


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	11.	     	Ownership
      of Proprietary Information and Inventions.
	 
	 		(a)	      	All Proprietary
      Information shall be the sole property of the Company and its assigns, and
      the Company and its assigns will be the sole owners of all inventions,
      patents, copyrights, trademarks, and other rights in connection therewith.
      You hereby assign to the Company any right you may have or acquire in such
      Proprietary Information. At all times, you will keep in strictest
      confidence and trust all Proprietary Information and you will not use or
      disclose any Proprietary Information without the written consent of the
      Company.
	 
	 		(b)		If your employment
      with the Company is terminated for any reason, you will deliver to the
      Company all documents, notes, drawings, specifications, computer software,
      data, inventions, organisms, and other materials of any nature pertaining
      to any Proprietary Information, and will not take any of the foregoing, or
      any reproduction of any of the foregoing, that is embodied in any tangible
      medium of expression. This shall not limit you from retaining your
      personal phone directories and rolodexes.
	 
	 		(c)		You will promptly
      disclose to the Company (or any persons designated by it) all discoveries,
      developments, designs, improvements, inventions, formulae, processes,
      techniques, computer software, strategies, know-how, and data, whether or
      not patentable or registrable under copyright or similar statutes, made or
      conceived or reduced to practice or learned by you, either alone or
      jointly with others, during your employment by the Company, which result
      from carrying out your responsibilities to the Company, or result from the
      use of premises or property owned, leased, or contracted for by the
      Company (all such discoveries, developments, designs, improvements,
      inventions, formulae, processes, techniques, computer software, know-how,
      and data are referred to in this Agreement as Inventions). You will also
      promptly disclose to the Company, and the Company agrees to receive all
      such disclosures in confidence, all other discoveries, developments,
      designs, improvements, inventions, formulae, processes, techniques,
      computer software, strategies, know-how, and data, whether or not
      patentable or registrable under copyright or similar statutes, made or
      conceived or reduced to practice or learned by you, either alone or
      jointly with others, during your employment by the Company for the purpose
      of determining whether they are Inventions, as that term is used in this
      Agreement. At all times during your employment by the Company you will use
      your reasonable business efforts to avoid conflicts of interest involving
      potential rights and claims of the Company and of third parties to
      Inventions, including those that might arise by virtue of your affiliation
      with a university or other medical institution concurrently with your
      employment by the Company and will take all action reasonably necessary
      and or desirable to minimize the probability of any such conflicts of
      interest and to maximize the likelihood that any Inventions made,
      conceived or developed or reduced to practice by you (alone or jointly
      with others) during your employment by the Company and which reasonably
      relate to the business of the Company will be and become the sole,
      unencumbered property of the Company, and no other third party (including,
      without limitation, any such university or other institution with whom you
      may also be affiliated) will have any rights thereto and that any such
      conflicts of interest be resolved in favor of the
  Company.


11 





	 		(d)	     	All Inventions shall
      be the sole property of the Company and its assigns, and the Company and
      its assigns shall be the sole owner of all patents, copyrights,
      trademarks, and other rights in connection therewith. You hereby assign to
      the Company any rights you may have or acquire in such Inventions. You
      will assist the Company in every proper way as to all such Inventions (but
      at the Company's expense) to obtain and from time to time enforce patents,
      copyrights, trademarks, and other rights and protections on and enforcing
      such Inventions, as the Company may desire, together with any assignments
      thereof to the Company or persons designated by it. Your obligation to
      assist the Company in obtaining and enforcing patents, copyrights,
      trademarks, and other rights and protections relating to such Inventions
      in any and all countries shall continue beyond the Employment Term. If the
      Company is unable, after reasonable effort, to secure your signature on
      any document or documents needed to apply for or prosecute any patent,
      copyright, or other right or protection relating to an Invention, for any
      other reason whatsoever, you hereby irrevocably designate and appoint the
      Company and its duly authorized officers and agents as your agent and
      attorney-in-fact, to act for and on your behalf to execute and file any
      such application or applications and to do all other lawfully permitted
      acts to further the prosecution and issuance of patents, copyrights, or
      similar protections thereon with the same legal force and effect as if
      executed by you and you hereby ratify, affirm, and approve all such
      lawfully permitted acts accordingly.
	 
	12.	     	Restricted Covenant.
	 
	 		(a)		You are aware that the
      services you perform for the Company are of a special, unique character.
      You also acknowledge your possession and future possession of Proprietary
      Information and the highly competitive nature of the business of the
      Company. Accordingly, you agree that, for the consideration set forth in
      this Agreement, you will not, without the written permission of the
      Company pursuant to Board of Directors authorization, during your
      employment under this Agreement and, if your employment ends as a result
      of your voluntary termination of employment pursuant to paragraph 4(e),
      for a period of one (1) year thereafter (six (6) months, in the event of
      any such termination after the occurrence of a Change of Control): (i)
      directly or indirectly engage or become interested or involved in any
      Competitive Business (as defined in subparagraph (b) below), whether such
      engagement, interest, or involvement shall be as an employer, officer,
      director, owner shareholder, employee, partner, consultant, or in any
      other capacity or relationship; provided, however, that this shall not
      preclude a passive investment of less than one (1%) of the stock of any
      publicly traded company; or (ii) materially assist others in engaging in
      any Competitive Business in the manner described in the foregoing clause
      (i); provided, further, that this shall not preclude you from providing
      investment banking services to or on behalf of an entity after your
      termination of employment that might otherwise be a Competitive Business
      so long as such services are to arrange a purchase, sale or other business
      combination for or with such entity or to arrange financing for such
      entity (including, without limitation, obtaining a bank loan for such
      entity or participating in the sale of the debt or equity securities of
      such entity).


12 





					You understand that
      this provision is not meant to prevent you from earning a living or
      fostering your career. It does intend, however, to prevent Competitive
      Businesses from gaining any unfair advantage from your knowledge of
      Proprietary Information. You understand that by making any other employer
      aware of this provision, that employer can take such action as to avoid
      your breach of this provision and to indemnify you in the event of a
      breach.
							  
			(b)	     	The term "Competitive
      Business" means:
							 
	 		 		(i)	     	For the period commencing on the
      date of this Agreement and ending on the date of your termination of
      employment any business or activity that is substantially the same as any
      business or activity of the Company as conducted by the Company or any
      Related Entity during such period; and
	 
	 		 		(ii)		For the period thereafter, any
      business or activity described in subparagraph (i) above to the extent
      that on the date of your termination of employment such business or
      activity represents at least 10% of the research and development budget of
      the Company for the fiscal year in which your termination occurs;
      provided, however, that any business or activity of the Company shall be
      deemed to have been conducted by the Company at the time of your
      termination of employment if the Company has undertaken steps to commence
      such business or activity prior to your termination of employment.
      Notwithstanding the foregoing, the provisions of this paragraph shall not
      operate to preclude your employment with (or providing consulting services
      to) any company that has a market capitalization at the time of your
      termination of employment of at least $500 million.
	 
	13.	    	Litigation Support. Subject to
      your other commitments, following the Employment Term, you shall make
      yourself reasonably available to cooperate (but only truthfully) with the
      Company and provide information as to matters with which you were
      personally involved, or have information on, while you were an officer of
      the Company and which are or become the subject of litigation or other
      dispute.


13 





	14.		General
      Provisions.
					 
		    	(a)	      	Death. Should you die before
      receipt of any or all severance payments to which you became entitled
      under paragraph 8, then the balance of the payments to which you are
      entitled shall continue to be paid in accordance with the terms hereof to
      the executors or administrators of your estate.
			 
			(b)		General Creditor
      Status. The amounts to which you may
      become entitled hereunder shall be paid, when due, from the general assets
      of the Company, and no trust fund, escrow arrangements, or other
      segregated account shall be established as a funding vehicle for such
      payment. Accordingly, your right (or the right of the executors or
      administrators of your estate) to receive such benefits shall at all times
      be that of a general creditor of the Company and shall have no priority
      over the claims of other general creditors.
			 
			(c)		Indemnification. During the
      Employment Term and thereafter, the Company shall indemnify you and hold
      you harmless to the fullest extent permitted by law against any judgments,
      fines, amounts paid in settlement and reasonable expenses (including
      reasonable attorneys' fees), and advance amounts necessary to pay the
      foregoing at the earliest time and to the fullest extent permitted by law,
      in connection with any claim, action or proceeding (whether civil or
      criminal) against you as a result of you serving as an officer or Director
      of the Company or in any capacity at the request of the Company in or with
      regard to any other entity, employee benefit plan or enterprise. This
      indemnification is in addition to and not in lieu of any other
      indemnification rights you may otherwise have.
			 
			(d)		Remedies. Your obligations under
      paragraphs 11 or 12 of this Agreement will survive termination of your
      employment by the Company. You acknowledge that a remedy at law for any
      breach or threatened breach of such provisions would be inadequate and
      therefore agree that the Company may be entitled to injunctive relief and
      any other available rights and remedies in case of any such breach or
      threatened breach; provided, however, that nothing contained in this
      subparagraph (d) will be construed as prohibiting the Company from
      pursuing any other remedies available for any such breach or threatened
      breach.
			 
			(e)		Interpretation. This Agreement
      shall be interpreted under the laws of the State of New York without
      regard to conflict of law provisions thereof.
			 
			(f)		Notices. Any notice which a
      party is required or may desire to give under this Agreement will be given
      by personal delivery, air courier, or registered or certified mail, return
      receipt requested, addressed to you at the address of record with the
      Company and addressed to the Secretary of the Company at its principal
      office, or at such other place as either party may from time to time
      designate in writing given as aforesaid. The date of delivery of any
      notice or communication will be deemed to be (i) the date of delivery
      thereof, in the case of personal delivery; (ii) the day after the date
      when dispatched, in the case of air courier; and (iii) the date of
      receipt, in the case of mailing.


14 





	         
	(g)	      	Waivers. If either party shall
      waive any breach of any provision of this Agreement, he or it will not
      thereby be deemed to have waived any preceding or succeeding breach of the
      same or any other provision of this Agreement.
		 
		(h)		Headings. The paragraph headings
      of this Agreement are for convenience only and will not be deemed to
      affect the meaning of the Agreement.
		 
		(i)		Superseding. This Agreement
      supersedes all prior agreements between you and the Company relating to
      the subject of your personal services and severance benefits, including
      the letter agreement dated September 14, 1993, which is hereby terminated.
      The provisions of this Agreement may only be amended by written instrument
      signed by you and a member of the Board of Directors.
		 
		(j)		No Guarantee of
      Employment or Service. Nothing in this
      Agreement is intended to provide you with any right to continue in the
      service of the Company for any period of specific duration, nor, except as
      specifically provided herein, to provide the Company with any right to
      require you to continue in the service of the Company.
		 
		(k)		Amendment or
      Termination. This Agreement may not be
      amended or terminated orally, but only by a writing executed by the party
      to be charged.
		 
		(l)		Assignment. None of the benefits
      to which you may become entitled hereunder may be assigned, transferred,
      pledged, or otherwise encumbered by you, and to the maximum extent
      permissible under law, such benefits will not be subject to the claims of
      your creditors or to levy, attachment, execution, or other legal process.
      This Agreement shall be binding upon and inure to the benefit of the
      Company, its successors and permitted assigns and your executors and
      heirs, provided that the Company may not assign the Agreement except in
      connection with a sale of all or substantially all of its assets and then
      only if said acquiror assumes in a writing delivered to you the
      obligations of the Company hereunder.
		 
		(m)		Costs of
      Collection. In the event either party
      collects any part or all of the payments provided for hereunder or
      otherwise successfully enforces the terms of this Agreement by or through
      a lawyer or lawyers, the losing party shall pay all costs of such
      collection or enforcement, including reasonable legal fees and other fees
      and expenses which the successful party may incur plus interest ("Costs");
      provided, however, that the Company shall not be entitled to recover any
      Costs from you unless an arbitrator determines that your action to recover
      any payment or to enforce the terms of this Agreement was not grounded on
      a reasonable good faith interpretation of the Agreement or that the action
      was undertaken for the primary purpose of harassing the Company. Interest
      shall be calculated at the prime rate as announced from time to time by
      Citibank, N.A. on all or any part of any amount to be paid to you
      hereunder that is not paid when due. The prime rate for each calendar
      quarter shall be the prime rate in effect on the first day of the calendar
      quarter. Any amounts due and payable to you on a favorable award of the
      arbitrator, pursuant to this paragraph 14(m) and paragraph 14(n), shall be
      paid within sixty (60) days following the date the arbitrator's decision
      becomes final.


15 





	          	(n)	      	Arbitration. Any dispute or
      controversy arising under or in connection with this Agreement shall be
      settled exclusively by arbitration, conducted before a panel of three (3)
      arbitrators in New York, New York, in accordance with the rules of the
      American Arbitration Association then in effect, and judgment may be
      entered on the arbitrators' award in any court having jurisdiction. The
      Company shall pay all costs of the American Arbitrator Association and the
      arbitrator. The decision upon arbitration shall be final and binding upon
      both you and the Company. Notwithstanding the foregoing, you shall be
      entitled to seek specific performance from a court of your right to be
      paid until the date of termination during the pendency of any dispute or
      controversy arising under or in connection with this Agreement and the
      Company shall have the right to obtain injunctive relief from a court
      pursuant to subparagraph (d) above.
	 	 
		(o)		Section
      409A. It is the intention of the
      parties hereto that the provisions of this Agreement comply with or be
      exempt from Section 409A of the Code and the regulations and guidance
      promulgated thereunder ("Section 409A") and that the Agreement shall be
      construed in accordance with such intention. Without limiting the
      generality of the foregoing, the Company and you agree as
    follows:
		 
		 		(i)	      	Reimbursements payable
      to you as a result of the operation of paragraph 3(c), paragraph 3(d),
      paragraph 3(f) (other than the "Grandfathered Reimbursements"), paragraph
      3(g), paragraph 3(h), paragraph 5, paragraph 8 (including paragraphs
      8(b)(iii) and 8(f)), paragraph 14(c) or paragraph 14(m) hereof, or any
      other provision in this Agreement regarding reimbursement, shall be paid
      to you within sixty (60) days following the date upon which you become
      entitled to the reimbursement (or such earlier date specified in this
      Agreement), but in no event later than the end of the calendar year
      following the year in which the expenses to be reimbursed are incurred
      (or, in the case of payments under paragraph 14(m), the year following the
      year in which you become entitled to reimbursement). Tax gross-up payments
      (and related reimbursements) payable to you as a result of the operation
      of paragraph 3(f), paragraph 5(b), paragraph 8(f), paragraph 9 or Exhibit
      C hereof, or any other provision in this Agreement regarding tax gross-up
      payments, shall be paid to you within sixty (60) days following the date
      upon which the tax resulting in the gross-up is paid, but in no event
      later than the end of the calendar year following the year in which the
      tax resulting in the gross-up is paid. With regard to such reimbursements
      and payments under this paragraph or elsewhere in the Agreement, except as
      permitted by Section 409A, (i) the right to reimbursement or in-kind
      benefits shall not be subject to liquidation or exchange for another
      benefit, and (ii) the amount of expenses eligible for reimbursement, or
      in-kind benefits, provided during any taxable year shall not affect the
      expenses eligible for reimbursement, or in-kind benefits to be provided,
      in any other taxable year, provided that the foregoing clause (ii) shall
      not be violated without regard to expenses reimbursed under any
      arrangement covered by Section 105(b) of the Code solely because such
      expenses are subject to a limit related to the period the arrangement is
      in effect.


16 





	                  
    	(ii)	     	Notwithstanding
      anything to the contrary herein, if you are a "specified employee" (within
      the meaning of Section 409A(a)(2)(B)(i) of the Code) with respect to the
      Company, (1) any amounts (or benefits) otherwise payable to or in respect
      of you under this Agreement pursuant to your termination of employment
      with the Company, which are deferred compensation under Section 409A,
      shall be delayed for a period of six months following such termination (or
      until death if earlier), so that taxes are not imposed on you pursuant to
      the operation of Section 409A, and shall be paid on first business day
      following the expiration such six month period and (2) any payments and
      benefits not required to be so delayed shall be paid or provided in
      accordance with this Agreement.
		 
		(iii)		For purposes of
      amounts under this Agreement which are subject to Section 409A, your
      employment with the Company will not be treated as terminated unless and
      until such termination of employment constitutes a "separation from
      service" for purposes of Section 409A.
		 
		(iv)		For purposes of
      Section 409A, to the extent that any payment payable under the Agreement
      is to be paid in installments, each such payment shall be treated as a
      separate identified payment for purposes of Section 409A. To the extent
      that the Agreement provides for a payment to be made on or before a
      specified date, the decision with respect to when to make such payment
      within the specified period shall be made in the sole discretion of the
      Company.
		 
		(v)		The Company shall
      gross you up for any taxes, interest or penalties incurred by you under
      Section 409A as a result of any payments or benefits hereunder or
      otherwise due from the Company in such a manner that you will have no
      after tax cost as a result thereof, as soon as practicable but in no event
      later than the last day of the calendar year following the calendar year
      in which such tax, interest or penalty is paid. You agree to reasonably
      cooperate with the Company in order to avoid the imposition of such taxes,
      it being understood that such cooperation shall not require you to forgo
      receipt or receive a reduced amount of payments or benefits due
      hereunder.


17 





Please indicate your acceptance by
signing the enclosed copy of this letter and returning it to the
Company.

	 	Very truly yours,
  


REGENERON PHARMACEUTICALS, INC.


	/s/ Arthur F.
      Ryan 	 
	Chairman of the Compensation  
	Committee of the Board of Directors 



 

AGREED TO AND ACCEPTED BY: 
LEONARD S. SCHLEIFER,
M.D., Ph.D.

	/s/ Leonard
      Schleifer              



18 





EXHIBIT A 

CHANGE OF CONTROL

For purposes of this Agreement, "Change
of Control" shall be deemed to have occurred if the event set forth in any one
of the following paragraphs shall have occurred:

	      	(i)	      	any "Person" (as
      defined in Section 3(a)(9) of the Securities Exchange Act of 1934, as
      amended (the "Exchange Act"), as modified and used in Sections 13(d) and
      14(d) thereof, except that such term shall not include (1) the Company,
      (2) a trustee or other fiduciary holding securities under an employee
      benefit plan of the Company, (3) an underwriter temporarily holding
      securities pursuant to an offering of such securities, or (4) a
      corporation owned, directly or indirectly, by the shareholders of the
      Company in substantially the same proportions as their ownership of stock
      of the Company) is or becomes the "Beneficial Owner" (as defined in Rule
      13d-3 under the Exchange Act), directly or indirectly, of securities of
      the Company (not including in the securities Beneficially Owned by such
      Person any securities acquired directly from the Company) representing 20%
      or more of the Company's then outstanding securities, excluding any Person
      who is an officer or director of the Company or who becomes such a
      Beneficial Owner in connection with a transaction described in clause (A)
      of paragraph (iii) below; or
		 
		(ii)		the following
      individuals cease for any reason to constitute a majority of the number of
      directors then serving: individuals who, on the date hereof, constitute
      the Board of Directors and any new director (other than a director whose
      initial assumption of office is in connection with an actual or threatened
      election contest, including but not limited to a consent solicitation,
      relating to the election of directors of the Company) whose appointment or
      election by the Board of Directors or nomination for election by the
      Company's shareholders was approved or recommended by a vote of at least
      two-thirds (2/3) of the directors then still in office who either were
      directors on the date hereof or whose appointment, election or nomination
      for election was previously so approved or recommended; or
		 
		(iii)		there is consummated a
      merger or consolidation of the Company with any other corporation other
      than (A) a merger or consolidation which would result in the voting
      securities of the Company outstanding immediately prior to such merger or
      consolidation continuing to represent (either by remaining outstanding or
      by being converted into voting securities of the surviving entity or any
      parent thereof) at least 60% of the combined voting power of the voting
      securities of the Company or such surviving entity or any parent thereof
      outstanding immediately after such merger or consolidation, or (B) a
      merger or consolidation effected to implement a recapitalization of the
      Company (or similar transaction) in which no Person is or becomes the
      Beneficial Owner, directly or indirectly, of securities of the Company
      (not including in the securities Beneficially Owned by such Person any
      securities acquired directly from the Company) representing 20% or more of
      the combined voting power of the Company's then outstanding securities;
      or
				 
		(iv)		the shareholders of the Company
      approve a plan of complete liquidation or dissolution of the Company or
      there is consummated an agreement for the sale or disposition by the
      Company of all or substantially all of the Company's assets, other than a
      sale or disposition by the Company of all or substantially all of the
      Company's assets to an entity at least 75% of the combined voting power of
      the voting securities of which are owned by Persons in substantially the
      same proportions as their ownership of the Company immediately prior to
      such sale.


1 





EXHIBIT B 

FORM OF RELEASE

	To:	     	Regeneron Pharmaceuticals, Inc.
      
777 Old Saw Mill River Road 
Tarrytown, New York 10591-6707
      
Attention: [General Counsel] 


      1. Termination. (a) I hereby acknowledge that my employment with Regeneron
Pharmaceuticals, Inc. (the "Company") [will terminate] [has terminated] on, (the
"Termination Date") pursuant to provisions of paragraphs 8 of my employment
agreement dated as of December 20, 2002 with the Company (the "Employment
Agreement"), that the Company will not have an obligation to rehire me or to
consider me for reemployment after the Termination Date and that my employment
with the Company is permanently and irrevocably severed.

     (b) I
hereby confirm my resignation from my position as President and Chief Executive
Officer of the Company and that I will not be eligible for any benefits or
compensation after the Termination Date, other than as specifically provided
hereunder and in paragraphs 3 and 8 of the Employment Agreement [or in any
capacity as a director of the Company]. In addition, effective as of the
Termination Date, I hereby resign from all offices, directorships, trusteeships,
committee memberships and fiduciary capacities held with, or on behalf of, the
Company or any of its affiliates or any benefit plans of the Company or any of
its affiliates [other than as a director]. These resignations will become
irrevocable on the Effective Date of this Agreement, as defined in Section 6
below.

     2.
Consideration. I acknowledge that this General Release is being executed in accordance
with paragraph 8(g) of the Employment Agreement.

     3.
General Release. (a) For and in consideration of the payments to be made and the promises
set forth under the Employment Agreement, I, for myself and for my heirs,
dependents, executors, administrators, trustees, legal representatives and
assigns (collectively referred to as "Releasors"), hereby forever release, waive
and discharge the Company, its affiliates, employee benefit and/or pension plans
or funds, insurers, successors and assigns, and all of its or their past,
present and/or future directors, officers, trustees, agents, members, partners,
counsel, employees, fiduciaries, administrators, representatives, successors and
assigns, whether acting on behalf of the Company or its affiliates or in their
individual capacities (collectively referred to as "Releasees"), from any and
all claims, demands, causes of action, fees and liabilities of any kind
whatsoever, whether known or unknown, which Releasors ever had, now have, or
hereafter may claim to have against Releasees by reason of any actual or alleged
act, omission, transaction, practice, policy, procedure, conduct, occurrence, or
other matter up to and including the date of my execution of this General
Release, in connection with, or in any way related to or arising out of, my
employment, service as a director, service as a trustee, service as a fiduciary
or termination of any of the foregoing with the Company.

1 





     (b)
Without limiting the generality of the foregoing, this General Release is
intended and shall release the Releasees from any and all claims, whether known
or unknown, which Releasors ever had, now have, or may hereafter claim to have
against the Releasees including, but not limited to, (i) any claim of
discrimination or retaliation under the Age Discrimination in Employment Act
("ADEA"), Title VII of the Civil Rights Act of 1964, the Americans with
Disabilities Act ("ADA"), the Employee Retirement Income Security Act of 1974 or
the Family and Medical Leave Act; (ii) any claim under the New York State Human
Rights Law and the New York City Administrative Code; (iii) any other claim
(whether based on federal, state or local law, statutory or decisional) relating
to or arising out of my employment, the terms and conditions of such employment,
the termination of such employment and/or any of the events relating directly or
indirectly to or surrounding the termination of such employment, including, but
not limited, breach of contract (express or implied), wrongful discharge,
tortious interference, detrimental reliance, defamation, emotional distress or
compensatory or punitive damages; and (iv) any claim for attorney's fees, costs,
disbursements and the like.

     (c) I
further acknowledge and agree that by virtue of the foregoing, I have waived all
relief available to me (including without limitation, monetary damages,
equitable relief and reinstatement) under any of the claims and/or causes of
action waived in Sections 3(a) and (b) above. Therefore I agree that I will not
seek or accept any award or settlement from any source or proceeding (including,
but not limited to, any proceeding brought by any other person or by any
government agency) with respect to any claim or right waived in this General
Release. I further agree, to the maximum extent permitted by law, that I will
not sue or commence any proceeding (judicial or administrative), or participate
in any action, suit or proceeding (unless compelled by legal process or court
order), against the Company (or any of its affiliates), with respect to any
claim released by Sections 3(a) and (b) above, other than a claim contesting the
validity of the release under applicable provisions of the ADEA. I also warrant
and represent that as of the date I sign this Agreement, I have not taken or
engaged in any of the acts described in the foregoing sentences. I understand
that this release has neither the purpose nor intent of interfering with my
protected right to file a charge with or participate in an investigation or
proceeding pursuant to the statutes administered and enforced by the EEOC,
specifically: the ADEA, the Equal Pay Act, Title VII of the Civil Rights Act of
1964 and the ADA. I understand that I will not breach this release if I file a
charge with or participate in an investigation or proceeding pursuant to the
statutes administered and enforced by the EEOC. However, by signing this
release, I understand that I waive any right I may have to recover money or
other relief in any lawsuit or proceeding brought by me or by an agency or third
party, including the EEOC, on my behalf. If, notwithstanding the foregoing
promises and understandings, I violate this Section 3(c), I shall be required,
to the maximum extent permitted by law, to indemnify and hold harmless the
Company (and its affiliates) from and against any and all demands, assessments,
judgments, costs, damages, losses and liabilities, and attorneys' fees and other
expenses which result from, or are incident to, such violation.

     (d)
Notwithstanding anything herein to the contrary, the sole matters to which the
release and covenants in this Section 3 do not apply are: (i) my rights of
indemnification and directors and officers liability insurance coverage which I
was entitled immediately prior to the Termination Date under the Company's
By-laws or otherwise with regard to my service as an officer and director of the
Company (including, without limitation, under paragraph 14(c) of the Employment
Agreement); (ii) my rights under any tax-qualified pension or tax deferred
annuity plan or claims for accrued vested benefits under any other employee
benefit plan, program, policy or arrangement maintained by the Company or under
COBRA; (iii) my rights under the provisions of the Employment Agreement which
are intended to survive termination of employment (including claims to payments,
benefits or entitlements specifically payable or provided under the Employment
Agreement); or (iv) my rights as a stockholder or as a director of the
Company.

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     4.
Governing Law; Enforceability. The interpretation of this General Release will be construed
and enforced in accordance with the laws of the State of New York without regard
to that state's principles of conflicts of law. If, at any time after the
execution of this General Release, any provision of this General Release will be
held to be illegal or unenforceable by a court of competent jurisdiction, solely
such provision will be of no force or effect.

     5.
Acknowledgement. I acknowledge that I have been advised by the Company in writing to
consult, and I have consulted, independent legal counsel of my choice before
signing this General Release. I further acknowledge that I have had the
opportunity to consult independent legal counsel and to consider the terms of
this General Release for a period of at least 21 days. I further acknowledge
that I have carefully read this General Release in its entirety; that I have had
an adequate opportunity to consider it and to consult with any advisors of my
choice about it; that I have consulted with independent legal counsel of my
choice who has answered to my satisfaction all questions I had regarding this
General Release; that I understand all the terms of this General Release and
their significance; that I am legally competent to execute this Agreement; that
I have not relied on any statements or explanations made by the Company, any
agent of the Company or its counsel; that I knowingly and voluntarily assent to
all the terms and conditions contained herein; and that I am signing this
General Release voluntarily and of my own free will.

     6. Effective Date. I further acknowledge that this General Release will not
become effective until the eighth day following my execution of this General
Release (the "Effective Date"), and that I may at any time prior to the
Effective Date revoke this General Release by delivering written notice of
revocation to the Company, at 777 Old Saw Mill River Road, Tarrytown, New York
10591-6707, to the attention of the [General Counsel]. In the event that I
revoke this General Release prior to the eighth day after its execution, this
General Release will automatically be null and void.

     7.
Survival.
The provisions in the Employment Agreement which are intended to survive
termination of employment hall survive and continue in full force and
effect.

Acknowledged and
Agreed:
REGENERON PHARMACEUTICALS,
INC.

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EXHIBIT C

GOLDEN PARACHUTE
PROVISION

(a) (i) In the event that you shall
become entitled to payments and/or benefits provided by this Agreement or any
other amounts in the "nature of compensation" (whether pursuant to the terms of
this Agreement or any other plan, arrangement or agreement with the Company, any
person whose actions result in a change of ownership or effective control
covered by Section 280G(b)(2) of the Code or any person affiliated with the
Company or such person) as a result of such change in ownership or effective
control (collectively the "Company Payments"), and such Company Payments will be
subject to the tax (the "Excise Tax") imposed by Section 4999 of the Code (and
any similar tax that may hereafter be imposed by any taxing authority) the
Company shall pay to you at the time specified in subsection (d) below (x) an
additional amount (the "Gross-up Payment") such that the net amount retained by
you, after deduction of any Excise Tax on the Company Payments and any U.S.
federal, state, and for local income or payroll tax upon the Gross-up Payment
provided for by this paragraph (a), but before deduction for any U.S. federal,
state, and local income or payroll tax on the Company Payments, shall be equal
to the Company Payments and (y) an amount equal to the product of any deductions
disallowed for federal, state or local income tax purposes because of the
inclusion of the Gross-Up Payment in your adjusted gross income multiplied by
your actual
applicable marginal rate of federal, state or local income taxation,
respectively, for the calendar year in which the Gross-Up Payment is to be
made.

     (ii)
Notwithstanding the foregoing, if it shall be determined that you are entitled
to a Gross-Up Payment, but that if the Company Payments (other than that portion
valued under Q&A 24(c) of the proposed regulations under Section 280G of the
Code(the "Stock Vesting Value")) (the "Cash Payments") are reduced by the amount
necessary such that the receipt of the Company Payments would not give rise to
any Excise Tax (the "Reduced Payment") and the Reduced Payment (other than the
Stock Vesting Value) would not be less than 90% of the Cash Payment, then no
Gross-Up Payment shall be made to you and the Cash Payments, in the aggregate,
shall be reduced to the Reduced Payments (other than the Stock Vesting Value).
If the Reduced Payments is to be effective, payments shall be reduced as
mutually agreed between the Company and you or, in the event the parties cannot
agree, in the following order (1) any lump sum severance based on a multiple of
Base Salary or annual bonus, (2) any other cash amounts payable to you and (3)
any benefits valued as parachute payments.

     (iii) In
the event that the Internal Revenue Service or court ultimately makes a
determination that the excess parachute payments plus the base amount is an
amount other than as determined initially, an appropriate adjustment shall be
made with regard to the Gross-Up Payment or Reduced Payment, as applicable to
reflect the final determination and the resulting impact on whether (ii)
applies.

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(b) For purposes of determining whether
any of the Company Payments and Gross-up Payments (collectively the "Total
Payments") will be subject to the Excise Tax and the amount of such Excise Tax,
(x) the Total Payments shall be treated as "parachute payments" within the
meaning of Section 280G(b)(2) of the Code, and all "parachute payments" in
excess of the "base amount" (as defined under Section 280G(b)(3) of the Code)
shall be treated as subject to the Excise Tax, unless and except to the extent
that, in the opinion, delivered to the Company and you at a level of more likely
than not, of the Company's independent certified public accountants appointed
prior to any change in ownership (as defined under Section 280G(b)(2) of the
Code) or tax counsel selected by such accountants (the "Accountants") such Total
Payments (in whole or in part) either do not constitute "parachute payments,"
represent reasonable compensation for services actually rendered within the
meaning of Section 280G(b)(4) of the Code in excess of the "base amount" or are
otherwise not subject to the Excise Tax, and (y) the value of any non-cash
benefits or any deferred payment or benefit shall be determined by the
Accountants in accordance with the principles of Section 280G of the Code. In
the event that the Accountants are serving (or decline to serve) as accountant
or auditor for the individual, entity or group effecting the Change of Control,
you may appoint another nationally recognized accounting firm or law firm to
make the determinations hereunder (which accounting firm or law firm shall then
be referred to as the "Accountants" hereunder). All determinations hereunder
shall be made by the Accountants which shall provide detailed supporting
calculations both to the Company and you at such time as it is requested by the
Company or you. If the Accountants determine that payments under this Agreement
must be reduced pursuant to this paragraph, they shall furnish you with a
written opinion to such effect. The determination of the Accountants shall be
final and binding upon the Company and you, subject to the other provisions
herein.

(c) For purposes of determining the
amount of the Gross-up Payment, you shall be deemed to pay U.S. federal income
taxes at actual
rate of U.S. federal income taxation in the calendar year in which the Gross-up
Payment is to be made and state and local income taxes at the rate of taxation
in the state and locality of your residence for the calendar year in which the
Company Payment is to be made, net of the reduction in U.S. federal income taxes
which could be obtained from deduction of such state and local taxes if paid in
such year. In the event that the Excise Tax is subsequently determined by the
Accountants to be less than the amount taken into account hereunder at the time
the Gross-up Payment is made, you shall repay to the Company, at the time that
the amount of such reduction in Excise Tax is finally determined, the portion of
the prior Gross-up Payment attributable to such reduction (plus the portion of
the Gross-up Payment attributable to the Excise Tax and U.S. federal, state and
local income tax imposed on the portion of the Gross-up Payment being repaid by
you if such repayment results in a reduction in Excise Tax or a U.S. federal,
state and local income tax deduction), plus interest on the amount of such
repayment at the rate provided in Section 1274(b)(2)(B) of the Code.
Notwithstanding the foregoing, in the event any portion of the Gross-up Payment
to be refunded to the Company has been paid to any U.S. federal, state and local
tax authority, repayment thereof (and related amounts) shall not be required
until actual refund or credit of such portion has been made to you, and interest
payable to the Company shall not exceed the interest received or credited to you
by such tax authority for the period it held such portion. Furthermore, to the
extent the foregoing provision shall be deemed to create a loan of a personal
nature in violation of Section 402 of the Sarbanes-Oxley Act of 2002, the
provision for repayment shall be null and void. You and the Company shall
mutually agree upon the course of action to be pursued (and the method of
allocating the expense thereof) if your claim for refund or credit is
denied.

In the event that the Excise Tax is
later determined by the Accountant or the Internal Revenue Service to exceed the
amount taken into account hereunder at the time the Gross-up Payment is made
(including by reason of any payment the existence or amount of which cannot be
determined at the time of the Gross-up Payment), the Company shall make an
additional Gross-up Payment in respect of such excess (plus any interest or
penalties payable with respect to such excess) at the time that the amount of
such excess is finally determined.

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(d) The Gross-up Payment or portion
thereof provided for in subsection (c) above shall be paid not later than the
thirtieth (30th) day following an event occurring which subjects you to the
Excise Tax; provided, however, that if the amount of such Gross-up Payment or
portion thereof cannot be finally determined on or before such day, the Company
shall pay to you on such day an estimate, as determined in good faith by the
Accountant, of the minimum amount of such payments and shall pay the remainder
of such payments (together with interest at the rate provided in Section
1274(b)(2)(B) of the Code), subject to further payments pursuant to subsection
(c) hereof, as soon as the amount thereof can reasonably be determined, but in
no event later than the ninetieth day after the occurrence of the event
subjecting you to the Excise Tax. In the event that the amount of the estimated
payments exceeds the amount subsequently determined to have been due, such
excess shall constitute a loan by the Company to you, payable on the fifth day
after demand by the Company (together with interest at the rate provided in
Section 1274(b)(2)(B) of the Code), provided that, to the extent the foregoing
provision shall be deemed to create a loan of a personal nature in violation of
Section 402 of the Sarbanes-Oxley Act of 2002, the provision for repayment shall
be null and void.

(e) In the event of any controversy
with the Internal Revenue Service (or other taxing authority) with regard to the
Excise Tax, you shall permit the Company to control issues related to the Excise
Tax (at its expense), provided that such issues do not potentially materially
adversely affect you, but you shall control any other issues. In the event the
issues are interrelated, you and the Company shall in good faith cooperate so as
not to jeopardize resolution of either issue, but if the parties cannot agree
you shall make the final determination with regard to the issues. In the event
of any conference with any taxing authority as to the Excise Tax or associated
income taxes, you shall permit the representative of the Company to accompany
you, and you and your representative shall cooperate with the Company and its
representative.

(f) The Company shall be responsible
for all charges of the Accountant.

(g) The Company and you shall promptly
deliver to each other copies of any written communications, and summaries of any
verbal communications, with any taxing authority regarding the Excise Tax
covered by this Exhibit C.

(h) Any Gross-Up Payments hereunder
shall be paid in the time and manner set forth in Section 14(o)(i) and (ii) of
the Agreement. 

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