Document:

Exhibit 10.1

 

EXECUTION VERSION

 

STOCK REPURCHASE AGREEMENT

 

BY AND BETWEEN

 

REGENERON PHARMACEUTICALS, INC.,

 

AND

 

SANOFI

 

Dated as of May 25, 2020 

 

STOCK REPURCHASE AGREEMENT

 

THIS STOCK REPURCHASE AGREEMENT (this
 “Agreement”) is made and entered into as of May 25, 2020 by and between Regeneron Pharmaceuticals, Inc.,
a New York corporation (“Regeneron”) and Sanofi, a company organized under the laws of France (“Sanofi”
or the “Selling Shareholder”).

 

WHEREAS, Regeneron and the Selling Shareholder
propose to enter into a transaction whereby the Selling Shareholder shall sell to Regeneron, and Regeneron shall purchase from
the Selling Shareholder, shares of Regeneron’s common stock, par value $0.001 per share (“Common Stock”),
as set forth in this Agreement (the “Repurchase Transaction”); and

 

WHEREAS, the Selling Shareholder and its
affiliates propose to sell through an underwritten public offering a base number of shares equal to all shares of Common Stock
held by the Selling Shareholder and its affiliates as of the date hereof (other than the Sanofi Shares (as defined below) subject
to the Repurchase Transaction, any shares of Common Stock subject to the underwriter option to purchase additional shares of Common
Stock in the offering, and 400,000 shares of Common Stock that Sanofi intends to retain) (the “Secondary Offering”).

 

NOW, THEREFORE, in consideration of the
foregoing, of the mutual promises herein set forth, and for other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, it is hereby agreed as follows:

 

ARTICLE I

 

REPURCHASE

 

Section 1.1 Repurchase of Common Stock.

 

(a) Under the terms and subject to the conditions
hereof and in reliance upon the representations, warranties and agreements contained herein, at the Closing (as defined below),
the Selling Shareholder shall sell to Regeneron such aggregate number of shares of Common Stock (such aggregate amount, the “Sanofi
Shares”) equal to $5,000,000,000 (Five Billion U.S. Dollars) (the “Purchase Price”), divided
by the price at which the shares of Common Stock are sold to the public in the Secondary Offering, less the underwriting discount
(the “Secondary Share Price”), and with the Sanofi Shares and the Purchase Price rounded down for any
fraction of a share.

 

Section 1.2 Closing. The closing
(the “Closing”) of the purchase of the Sanofi Shares shall be held at the offices of Wachtell, Lipton,
Rosen & Katz, 51 West 52nd Street, New York, New York immediately subsequent to the satisfaction or waiver of the
conditions set forth in Articles V and VI herein (the “Closing Date”), by telephonic meeting on such
date or at such other time, date or place as the Selling Shareholder and Regeneron may agree in writing.

 

    

     

    

 

Section 1.3 Deliveries.

 

(a) At the Closing, the Selling Shareholder
shall deliver or cause to be delivered to Regeneron (collectively, the “Selling Shareholder Closing Deliveries”):

 

		(i)	the Sanofi Shares to Regeneron in the form attached hereto as Exhibit A, or pursuant to such form as the transfer agent
for the Common Stock shall require, free and clear of any Lien (as defined below); and

 

		(ii)	a completed and executed original copy of Internal Revenue Service (the “IRS”) Form W-8 BEN-E.

 

(b) At the Closing, Regeneron shall deliver,
or cause to be delivered, to the Selling Shareholder the Purchase Price, payable by wire transfer of immediately available funds
to an account or accounts that the Selling Shareholder shall designate in writing at least two business days prior to the Closing
Date.

 

ARTICLE II

 

REPRESENTATIONS AND WARRANTIES OF
THE SELLING SHAREHOLDER

 

The Selling Shareholder hereby represents
and warrants to Regeneron as follows:

 

Section 2.1 Title to Sanofi Shares.
As of the Closing, the Selling Shareholder shall own and shall deliver the Sanofi Shares, free and clear of any and all option,
call, contract, commitment, mortgage, pledge, security interest, encumbrance, lien, tax, claim or charge of any kind or right of
others of whatever nature, other than any arising out of, resulting from or in connection with any agreement, arrangement or understanding
between Sanofi or any of its subsidiaries and Regeneron (collectively, a “Lien”).

 

Section 2.2 Authority Relative to this
Agreement. The Selling Shareholder has the requisite corporate power and authority to execute and deliver this Agreement and
to consummate the transactions contemplated hereby. The execution and delivery of this Agreement by the Selling Shareholder and
the consummation by the Selling Shareholder of the transactions contemplated hereby, including the sale of the Sanofi Shares, has
been duly authorized by the board of directors of Sanofi and no other corporate or stockholder proceedings on the part of the Selling
Shareholder is necessary to authorize this Agreement or for the Selling Shareholder to consummate the transactions contemplated
hereby. This Agreement has been duly and validly executed and delivered by the Selling Shareholder and constitutes the valid and
binding obligations of the Selling Shareholder, enforceable against the Selling Shareholder in accordance with its terms, except
as may be limited by bankruptcy, insolvency or other equitable remedies.

 

Section 2.3 Approvals. No material
consent, approval, authorization or order of, or registration, qualification or filing with, any court, regulatory authority, governmental
body or any other third party is required to be obtained or made by the Selling Shareholder for the execution, delivery or performance
by the Selling Shareholder of this Agreement or the consummation by the Selling Shareholder of the transactions contemplated hereby.

 

Section 2.4 Receipt of Information.
The Selling Shareholder has received all the information it considers necessary or appropriate for deciding whether to dispose
of the Sanofi Shares. The Selling Shareholder has had an opportunity to ask questions and receive answers from Regeneron regarding
the terms and conditions of Regeneron’s purchase of the Sanofi Shares and the business and financial condition of Regeneron
and to obtain additional information (to the extent Regeneron possessed such information or could acquire it without unreasonable
effort or expense) necessary to verify the accuracy of any information furnished to them or to which they had access. The Selling
Shareholder and its counsel has also had an opportunity to participate in the diligence process related to the Secondary Offering.
The Selling Shareholder has not received, or is not relying on, any representations or warranties from Regeneron, other than as
provided herein.

 

Section 2.5 Full Disclosure. The
Selling Shareholder is not aware of any fact, condition or circumstance that may materially affect the collaborations between Sanofi
and Regeneron or any marketed products pursuant to such collaborations that they have not previously disclosed to Regeneron orally
or in writing.

 

Section 2.6 Treatment of Repurchase.
No portion of the Purchase Price will be treated as a dividend under Section 301 of the Internal Revenue Code of 1986, as amended
(the “Code”) by reason of Section 302 of the Code or otherwise.

 

    2

     

    

 

ARTICLE III

 

REPRESENTATIONS AND WARRANTIES OF
REGENERON

 

Regeneron hereby represents and warrants
to the Selling Shareholder as follows:

 

Section 3.1 Authority Relative to this
Agreement. Regeneron has the requisite corporate power and authority to execute and deliver this Agreement and consummate the
transactions contemplated hereby. The execution and delivery of this Agreement by Regeneron, and the consummation by Regeneron
of the transactions contemplated hereby, including the purchase of the Sanofi Shares have been duly authorized by Regeneron’s
board of directors, and no other corporate or stockholder proceedings on the part of Regeneron are necessary to authorize this
Agreement or to consummate the transactions contemplated hereby. This Agreement has been duly and validly executed and delivered
by Regeneron and constitutes the valid and binding obligations of Regeneron, enforceable against Regeneron in accordance with its
terms, except as may be limited by bankruptcy, insolvency or other equitable remedies.

 

Section 3.2 Approvals. No material
consent, approval, authorization or order of, or registration, qualification or filing with, any court, regulatory authority, governmental
body or any other third party is required to be obtained or made by Regeneron for the execution, delivery or performance by Regeneron
of this Agreement or the consummation by Regeneron of the transactions contemplated hereby.

 

Section 3.3 Funds. Regeneron will
have as of the Closing sufficient cash available to pay the Purchase Price to the Selling Shareholder on the terms and conditions
contained herein.

 

ARTICLE IV

 

ADDITIONAL AGREEMENTS

 

Section 4.1 Additional Agreements.
The parties shall and shall cause their respective subsidiaries to take such action and execute, acknowledge and deliver such agreements,
instruments and other documents as the other party may reasonably require from time to time in order to carry out the purposes
of this Agreement.

 

Section 4.2 Public Announcements.
Except as may be required by applicable law, neither party hereto shall make any public announcements or otherwise communicate
with any news media with respect to this Agreement or any of the transactions contemplated hereby (a “Public Announcement”),
without prior consultation with the other party as to the timing and contents of any such announcement or communications; provided,
however, that nothing contained herein shall prevent any party from promptly making any filings with any governmental entity (including,
for the avoidance of doubt, the U.S. Securities and Exchange Commission) or disclosures with the stock exchange, if any, on which
such party’s capital stock is listed, as may, in its judgment, be required in connection with the execution and delivery
of this Agreement or the consummation of the transactions contemplated hereby.

 

Section 4.3 Withholding.
Regeneron shall pay the Purchase Price to the Selling Shareholder, free and clear of, and without reduction or withholding
for, any taxes. The Selling Shareholder shall indemnify Regeneron against any and all taxes required to be deducted or
withheld from the Purchase Price for any reason, including, without limitation, the treatment of all or any portion of the
Purchase Price as a distribution under Sections 302(d) and 301 of the Code (and any and all related losses, claims,
liabilities, penalties, interest, costs, and expenses incurred by Regeneron as a result of Regeneron’s failure to
deduct or withhold any such amounts).  In the case of any written claim or written challenge by the IRS or any other
governmental authority that deduction and withholding from the Purchase Price are or were required (a “Tax
Claim”), Regeneron (i) shall provide the Selling Shareholder with written notice of such Tax Claim, (ii) shall
consult with the Selling Shareholder regarding any challenge or defense of such Tax Claim and shall offer the Selling
Shareholder an opportunity to comment (and shall consider in good faith any such comments) before submitting any written
materials prepared or furnished in connection with such Tax Claim, and (iii) shall not settle or compromise any such Tax
Claim without the prior written consent of the Selling Shareholder, which consent shall not be unreasonably withheld,
conditioned or delayed. Notwithstanding the foregoing, the parties hereto agree that, under applicable law as of the date
hereof and assuming the accuracy of the representation in Section 2.6 and the delivery of the certificate required by Section
1.3(a)(ii), no deduction or withholding for any taxes are required with respect to the payment of the Purchase Price, and the
parties further agree that neither party shall take a contrary position for any purpose absent either a relevant change in
tax law or a final determination (within the meaning of Section 1313(a) of the Code) to the contrary.

 

    3

     

    

 

ARTICLE V

 

CONDITIONS TO CLOSING OF REGENERON

 

The obligation of Regeneron to purchase
the Sanofi Shares at the Closing is subject to the fulfillment on or prior to the Closing of each of the following conditions:

 

Section 5.1 Representations and Warranties.
Each representation and warranty made by the Selling Shareholder in Article II above shall be true and correct on and as of the
Closing Date as though made as of the Closing Date.

 

Section 5.2 Performance. All covenants,
agreements and conditions contained in this Agreement to be performed or complied with by the Selling Shareholder on or prior to
the Closing Date shall have been performed or complied with by the Selling Shareholder in all material respects.

 

Section 5.3 Closing Certificate.
The Selling Shareholder shall have delivered to Regeneron a certificate, dated as of the Closing Date and signed by an authorized
signatory of the Selling Shareholder, certifying to the effect that the conditions set forth in Sections 5.1 and 5.2 have been
satisfied.

 

Section 5.4 Certificates and Documents.
The Selling Shareholder shall have delivered at or prior to the Closing to Regeneron or its designee the Selling Shareholder Closing
Deliveries.

 

Section 5.5 Completion of Secondary Offering.
The Secondary Offering shall have been consummated in accordance with the terms and conditions of any underwriting or purchase
agreement entered into in connection therewith such that the number of shares of Common Stock held by the Selling Shareholder and
its affiliates following the Secondary Offering and the Repurchase Transaction would be no greater than 400,000 shares of Common
Stock plus any shares of Common Stock retained by the Selling Shareholder as a result of the underwriters for the Secondary Offering
not exercising their overallotment option to purchase additional shares of Common Stock in full. For greater certainty, all references
to the consummation of the Secondary Offering contained herein do not require the exercise of any option granted to the underwriters
for such offering.

 

ARTICLE VI

 

CONDITIONS TO CLOSING OF THE SELLING
SHAREHOLDER

 

The obligation of the Selling Shareholder
to sell the Sanofi Shares to Regeneron at the Closing is subject to the fulfillment on or prior to the Closing of each of the following
conditions:

 

Section 6.1 Representations and Warranties.
Each representation and warranty made by Regeneron in Article III above shall be true and correct on and as of the Closing Date
as though made as of the Closing Date.

 

Section 6.2 Performance. All covenants,
agreements and conditions contained in this Agreement to be performed or complied with by Regeneron on or prior to the Closing
Date shall have been performed or complied with by Regeneron in all material respects.

 

Section 6.3 Certificate. Regeneron
shall have delivered to the Selling Shareholder a certificate, dated as of the Closing Date and signed by an authorized signatory
of Regeneron, certifying to the effect that the conditions set forth in Sections 6.1 and 6.2 have been satisfied.

 

Section 6.4 Purchase Price. Regeneron
shall have delivered to the Selling Shareholder or its designee or designees the Purchase Price, payable by wire transfer of immediately
available funds to the account or accounts that the Selling Shareholder shall designate at least two business days prior to the
Closing Date.

 

    4

     

    

 

Section 6.5 Completion of Secondary
Offering. The Secondary Offering shall have been consummated in accordance with the terms and conditions of any
underwriting or purchase agreement entered into in connection therewith such that the number of shares of Common Stock held
by the Selling Shareholder and its affiliates following the Secondary Offering and the Repurchase Transaction would be no
greater than 400,000 shares of Common Stock plus any shares of Common Stock retained by the Selling Shareholder as a result
of the underwriters for the Secondary Offering not exercising their overallotment option to purchase additional shares of
Common Stock in full. For greater certainty, all references to the consummation of the Secondary Offering contained herein do
not require the exercise of any option granted to the underwriters for such offering.

 

ARTICLE VII

 

MISCELLANEOUS

 

Section 7.1 Termination. This Agreement
may be terminated prior to the Closing as follows: (i) at any time on or prior to the Closing, by mutual written consent of the
Selling Shareholder and Regeneron or (ii) at the election of the Selling Shareholder or Regeneron by written notice to the other
party hereto after 5:00 p.m., New York time, on June 5, 2020, if the Closing shall not have occurred, unless such date is extended
by the mutual written consent of the Selling Shareholder and Regeneron; provided, however, that the right to terminate this
Agreement pursuant to this clause (ii) shall not be available to a party whose failure or whose subsidiaries’ or affiliate’s
failure to perform or observe in any material respect any of its obligations under this Agreement in any manner shall have been
the principal cause of or resulted in the failure of the Closing to occur on or before such date.

 

Section 7.2 Amendment and Waiver.
This Agreement may not be amended except by an instrument in writing signed on behalf of each of the parties hereto. The failure
of any party to enforce any of the provisions of this Agreement shall in no way be construed as a waiver of such provisions and
shall not affect the right of such party thereafter to enforce each and every provision of this Agreement in accordance with its
terms.

 

Section 7.3 Severability. The provisions
of this Agreement shall be deemed severable and the invalidity or unenforceability of any provision shall not affect the validity
or enforceability of the other provisions hereof. Any term or provision of this Agreement which is invalid or unenforceable in
any jurisdiction shall, as to that jurisdiction, be ineffective to the extent of such invalidity or unenforceability without rendering
invalid or unenforceable the remaining terms and provisions of this Agreement in any other jurisdiction and a suitable and equitable
provision shall be substituted therefor in order to carry out, so far as may be valid and enforceable, the intent and purpose of
such invalid or unenforceable provision.

 

Section 7.4 Entire Agreement. Except
as otherwise expressly set forth herein, this Agreement, together with the several agreements and other documents and instruments
referred to herein or therein or annexed hereto and executed contemporaneously herewith, embody the complete agreement and understanding
among the parties hereto with respect to the subject matter hereof and supersede and preempt any prior understandings, agreements
or representations by or among the parties, written or oral, that may have related to the subject matter hereof in any way.

 

Section 7.5 Successors and Assigns.
Neither this Agreement nor any of the rights or obligations of any party under this Agreement shall be assigned, in whole or in
part by any party without the prior written consent of the other parties.

 

Section 7.6 Counterparts. This Agreement
may be executed in separate counterparts each of which shall be an original and all of which taken together shall constitute one
and the same agreement.

 

Section 7.7 Remedies.

 

(a) Each party hereto acknowledges that
monetary damages would not be an adequate remedy in the event that each and every one of the covenants or agreements in this Agreement
are not performed in accordance with their terms, and it is therefore agreed that, in addition to and without limiting any other
remedy or right it may have, the non-breaching party shall have the right to an injunction, temporary restraining order or other
equitable relief in any court of competent jurisdiction enjoining any such breach and enforcing specifically each and every one
of the terms and provisions hereof. Each party hereto agrees not to oppose the granting of such relief in the event a court determines
that such a breach has occurred, and to waive any requirement for the securing or posting of any bond in connection with such remedy.

 

    5

     

    

 

(b) All rights, powers and remedies provided
under this Agreement or otherwise available in respect hereof at law or in equity shall be cumulative and not alternative, and
the exercise or beginning of the exercise of any thereof by any party shall not preclude the simultaneous or later exercise of
any other such right, power or remedy by such party.

 

Section 7.8 Notices. All notices
and other communications hereunder shall be in writing and shall be deemed given if delivered personally, sent by electronic mail,
telecopied (upon telephonic confirmation of receipt), on the first business day following the date of dispatch if delivered by
a recognized next day courier service, or on the third business day following the date of mailing if delivered by registered or
certified mail, return receipt requested, postage prepaid. All notices hereunder shall be delivered as set forth below, or pursuant
to such other instructions as may be designated in writing by the party to receive such notice.

 

If to Regeneron:

 

Regeneron Pharmaceuticals, Inc.

777 Old Saw Mill River Road

Tarrytown, New York 10591

Attention: Joseph J. LaRosa, Joseph.LaRosa@regeneron.com

Executive Vice President, General Counsel and Secretary

 

with a copy (which shall not constitute notice) to:

Wachtell, Lipton, Rosen & Katz, LLP

51 West 52nd Street

New York, NY 10019

Attention: Andrew R. Brownstein, ARBrownstein@wlrk.com

Elina Tetelbaum, ETetelbaum@wlrk.com

If to the Selling Shareholder:

 

Sanofi

54, rue La Boétie

75008 Paris – France

Email: global_generalcounsel@sanofi.com

Attention: General Counsel, karen.linehan@sanofi.com

 

with a copy (which shall not constitute notice) to:

 

Weil, Gotshal & Manges

767 5th Avenue

New York, NY 10153

Attention: Michael J. Aiello, michael.aiello@weil.com

Alexander D. Lynch, alex.lynch@weil.com

Eoghan P. Keenan, eoghan.keenan@weil.com

 

    6

     

    

 

Section 7.9 Governing Law; Consent to
Jurisdiction.

 

(a) This Agreement shall be governed
by and construed in accordance with the laws of the State of New York, without regard to the conflict of laws principles
thereof that would require the application of the law of any other jurisdiction. The parties irrevocably and unconditionally
consent to submit to the exclusive jurisdiction of the United States District Court for the Southern District of New York
solely and specifically for any action, proceeding or investigation in any court or before any governmental authority
(“Litigation”) arising out of or relating to this Agreement and the transactions contemplated
hereby. Each of the parties hereto hereby irrevocably and unconditionally waives, and agrees not to assert, by way of motion,
as a defense, counterclaim or otherwise, in any such Litigation, the defense of sovereign immunity, any claim that it is not
personally subject to the jurisdiction of the aforesaid courts for any reason other than the failure to serve process in
accordance with this Section 7.9, that it or its property is exempt or immune from jurisdiction of any such court or from any
legal process commenced in such courts (whether through service of notice, attachment prior to judgment, attachment in aid of
execution of judgment, execution of judgment or otherwise), and to the fullest extent permitted by applicable law, that the
Litigation in any such court is brought in an inconvenient forum, that the venue of such Litigation is improper, or that this
Agreement, or the subject matter hereof, may not be enforced in or by such courts and further irrevocably waives, to the
fullest extent permitted by applicable law, the benefit of any defense that would hinder, fetter or delay the levy, execution
or collection of any amount to which the party is entitled pursuant to the final judgment of any court having jurisdiction.
Each of the parties irrevocably and unconditionally waives, to the fullest extent permitted by applicable law, any and all
rights to trial by jury in connection with any Litigation arising out of or relating to this Agreement or the transactions
contemplated hereby.

 

(b) Each of the parties expressly acknowledges
that the foregoing waiver is intended to be irrevocable under the laws of the State of New York and of the United States of America;
provided that consent by the Selling Shareholder and Regeneron to jurisdiction and service contained in this Section 7.9
is solely for the purpose referred to in this Section 7.9 and shall not be deemed to be a general submission to said courts or
in the State of New York other than for such purpose.

 

Section 7.10 Interpretation. The
headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation
of this Agreement. Whenever the words “include”, “includes” or “including” are used in this
Agreement, they shall be deemed to be followed by the words “without limitation”.

 

[Signature Pages Follow] 

 

    7

     

    

 

IN WITNESS WHEREOF, the parties hereto have caused this Stock
Repurchase Agreement to be duly executed and delivered as of the date first above written.

 

	 	SANOFI
	 	 
	 	By:	
        /s/ Karen Linehan

	 	Name: Karen Linehan
	 	Title: Executive Vice President, Legal Affairs
and
	 	General Counsel

 

 

	 	REGENERON PHARMACEUTICALS, INC.
	 	 
	 	By:	
        /s/ Robert E. Landry

	 	Name: Robert E. Landry
	 	Title: Executive Vice President,
Finance and Chief
	 	Financial Officer

 

[Signature Page
to Stock Repurchase Agreement]

 

    

     

    

 

Exhibit A

[Transfer of Stock Ownership Form]

 

    

     

    

 

STOCK
POWER

 

FOR
VALUE RECEIVED, SANOFI SA HEREBY ASSIGNS AND TRANSFERS UNTO _______________________________, TWELVE MILLION
(12,000,000) SHARES OF THE COMMON STOCK OF REGENERON PHARMACEUTICALS, INC. STANDING IN HIS/HER NAME ON THE BOOKS OF
SAID CORPORATION REPRESENTED BY CERTIFICATE/BOOK NOS. RE-9025, RE-9026, RE- 9027, RE-9028, RE-9029, RE-9030, RE-9031, RE-9032, RE-9033, RE-9034, RE-9035
and RE-9036 HEREWITH, AND DOES HEREBY IRREVOCABLY CONSTITUTE AND APPOINT AMERICAN STOCK TRANSFER & TRUST
COMPANY, LLC ATTORNEY TO TRANSFER THE SAID STOCK ON THE BOOKS OF SAID CORPORATION WITH FULL POWER OF SUBSTITUTION IN THE
PREMISES.

 

	DATED: MAY [●], 2020	 	 
	 	 	 
	 	SELLING
    STOCKHOLDER (if entity)	 	SELLING
    STOCKHOLDER (if individual)
	 	 	 	 
	 	Sanofi
    SA	 	 
	 	(Name of Entity*)	 	(Print Legibly
    – Name of Selling Stockholder*)
	 	 	 	 
	 	By:	 	 
	 	(Signature)	 	 
	 	 	 	(Signature*)
	 	 	 	 
	 	(Print Name of
    Person Signing)	 	 
	 	 	 	 
	 	 	 	 
	 	 	 	 
	 	(Print
Title of Person Signing)	 	 

 

____________

*
To be signed in exactly the same name as the shares are registered.Exhibit 10.2

 

EXECUTION VERSION

 

Regeneron Pharmaceuticals, Inc.

777 Old Saw Mill River Road

Tarrytown, New York 10591

 

May 25, 2020

 

Sanofi

54, rue La Boétie

75008 Paris

France

Attention: Chief Financial Officer

 

		Re:	Amendment of Investor Agreement

 

Ladies and Gentlemen:

 

Reference is made to the Amended and Restated
Investor Agreement (as may be amended from time to time, the “Investor Agreement”), dated as of January 11,
2014, by and among Sanofi, a company organized under the laws of France (“Sanofi”), sanofi-aventis US LLC, a
Delaware limited liability company (“Sanofi US”), Aventisub LLC, a Delaware limited liability company (formerly
Aventis Pharmaceuticals Inc., a Delaware corporation) (“Aventis”), sanofi-aventis Amérique du Nord, a
société en nom collectif organized under the laws of France (the “Investor”, which was
merged with Sanofi on October 30, 2018, and, together with Sanofi, Sanofi US and Aventis, the “Purchaser Parties”),
and Regeneron Pharmaceuticals, Inc., a New York corporation (“Regeneron”), as amended pursuant to that certain
letter agreement, dated as of January 7, 2018, by and among Regeneron and the affiliates of the Purchaser Parties party thereto
(the “2018 Letter Agreement”). Capitalized terms that are used but not defined herein have the meanings given
to such terms in the Investor Agreement.

 

The purpose of this Letter Agreement is
to provide for certain matters in connection with (i) the underwritten offering by Sanofi and Aventis of shares (the “Offering
Shares”) of common stock, par value $0.001 per share, of Regeneron (“Common Stock”) pursuant to Regeneron’s
Registration Statement on Form S-3 (Registration No. 333-228352), with a base public offering size equal to all shares of Common
Stock held by Sanofi and its Affiliates as of the date hereof (other than the Repurchase Shares (as defined below), any shares
of Common Stock subject to the underwriter overallotment option to purchase additional Offering Shares and 400,000 shares of Common
Stock that Sanofi intends to retain) (such offering, the “Offering”) and (ii) the repurchase (the “Repurchase”
and, together with the Offering, the “Transaction”) by Regeneron of approximately $5 billion of Common Stock
from Sanofi at the price at which the Offering Shares are sold to the public in the Offering, less the underwriting discount (the
 “Repurchase Shares”) pursuant to the Stock Repurchase Agreement, dated as of the date hereof, by and between
Sanofi, Aventis and Regeneron.

 

     

     

    

 

	Sanofi	Page 2 of 4
	May 25, 2020	 

 

Pursuant to Sections 9.2 and 9.5 of the
Investor Agreement, the parties to this Letter Agreement agree as follows:

 

		(1)	Termination of Registration Rights (Section 2 of the Investor Agreement). Effective as of and conditioned upon the closing
of the Offering (without regard to any underwriter overallotment option to purchase additional Offering Shares) and the Repurchase
(the “Closing”), Section 2 of the Investor Agreement (comprising Sections 2.1 through 2.12 of the Investor Agreement)
is hereby terminated and has no further force and effect.

 

		(2)	Termination of Board Designation Right (Section 3.1 of the Investor Agreement). Effective as of and conditioned upon
the Closing, Section 3.1 of the Investor Agreement is hereby terminated and has no further force and effect.

 

		(3)	Survival of Standstill (Section 4.1 of the Investor Agreement). For the avoidance of doubt, Section 4.1 of the Investor
Agreement shall continue in full force and effect pursuant to its terms following the Closing.

 

		(4)	Survival of Restrictions on Dispositions (Section 5 of the Investor Agreement). Section 5 of the Investor Agreement
(comprising Sections 5.1 through 5.4 of the Investor Agreement) shall continue in full force and effect pursuant to its terms,
including the length of the Lock-Up Term, and shall apply to any shares of Common Stock beneficially owned by any Purchaser Party
or Permitted Transferee following the Closing; provided that the funding mechanics and related provisions set forth in the
2018 Letter Agreement relating to the REGN2810 Development Costs and certain Dupilumab/REGN3500 Eligible Investments (each as defined
in the 2018 Letter Agreement) shall apply to any such shares. For the avoidance of doubt, (a) this Letter Agreement shall not modify
the rights of any Purchaser Party to transfer shares of Common Stock to a Permitted Transferee pursuant to and in compliance with
the terms of the Investor Agreement and (b) Section 5.2(a) of the Investor Agreement shall continue to apply with respect to any
underwritten public offering by the Purchaser Parties of shares of Common Stock following the expiration of the Lock-Up Term.

 

		(5)	Survival of Voting Agreement (Section 6 of the Investor Agreement). Section 6 of the Investor Agreement (comprising
Sections 6.1 through 6.3 of the Investor Agreement) shall continue in full force and effect with respect to any shares of Common
Stock beneficially owned by any Purchaser Party following the Closing so long as any Purchaser Party or Permitted Transferee holds
any shares of Common Stock held by any Purchaser Party immediately following the consummation of the Transaction; and, for the
avoidance of doubt, it shall not terminate as a result of the Offering or the Purchaser Parties ceasing to own five percent (5%)
of the voting power of Common Stock.

 

		(6)	Changes to Termination Provisions (Section 7 of the Investor Agreement).

 

		(a)	Effective as of and conditioned upon the Closing, Section 7.1 of the Investor Agreement is hereby replaced in its entirety
with the following:

 

“7.1 [Reserved.]”

 

     

     

    

 

	Sanofi	Page 3  of 4
	May 25, 2020	 

 

		(b)	Effective as of and conditioned upon the Closing, Section 7.4(c) of the Investor Agreement is hereby replaced in its entirety
with the following:

 

“(c) [Reserved.]”

 

		(7)	Termination of Other Rights (Section 8 of the Investor Agreement). Effective as of and conditioned upon the Closing,
Section 8 of the Investor Agreement (comprising Sections 8.1 and 8.2 of the Investor Agreement) is hereby terminated and has no
further force and effect.

 

Except as expressly set forth herein or
in the waiver letter, dated as of the date hereof, by and among Regeneron and the Purchaser Parties, no provision of the Investor
Agreement is modified or waived, and the Investor Agreement shall continue in full force and effect in accordance with its terms.
All references in the Investor Agreement to the Investor Agreement shall be deemed to be references to the Investor Agreement after
giving effect to this Letter Agreement.

 

Please confirm your agreement with the foregoing
by returning a countersigned acknowledgement.

 

[Signature page follows.]

 

     

     

    

 

	 	Sincerely,
	 
	 	REGENERON PHARMACEUTICALS, INC.
	 
	 	By:	 /s/ Robert E. Landry                    
	 	Name: Robert E. Landry
	 	Title: Executive Vice President, Finance and Chief Financial Officer
	 
	Acknowledged and Agreed as of the Date Set forth Above:
	 
	SANOFI
	 
	By:	 /s/ Karen Linehan	 	 
	Name: Karen Linehan
	Title: Executive Vice President, Legal Affairs and General Counsel
	 
	SANOFI-AVENTIS US LLC
	 
	By:	/s/ Karen Linehan	 
	Name: Karen Linehan
	Title: Attorney-in-Fact
	 
	AVENTISUB LLC
	 
	By:	 /s/ Karen Linehan	 
	Name: Karen Linehan
	Title: Attorney-in-Fact

 

[Signature
Page to Amendment to the Investor Agreement]

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