Statement of Changes in Beneficial Ownership (4)

FORM 4

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * Sanofi	2. Issuer Name and Ticker or Trading Symbol REGENERON PHARMACEUTICALS, INC. [ REGN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director                    __X__ 10% Owner _____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle) 54 RUE LA BOETIE	3. Date of Earliest Transaction (MM/DD/YYYY) 3/9/2020
(Street) PARIS, I0 75008 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	3/9/2020		S(1)		128914	D	$489.6532	20421899	D (3)
Common Stock								2799552	I (3)	See note (2)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:
(1)	Private sale to the Issuer pursuant to the letter agreement entered into with the Issuer on January 7, 2018 and filed on January 9, 2018 by the Reporting Person as Exhibit 99.4 to Amendment No. 13 to Reporting Person's statement on Schedule 13D.
(2)	Directly owned by Aventisub LLC ("Aventisub"), formerly known as Aventis Pharmaceuticals Inc., an indirect, wholly-owned subsidiary of the Reporting Person.
(3)	Pursuant to the Amended and Restated Investor Agreement, dated as of January 11, 2014, by and among the Reporting Person, sanofi-aventis US LLC, Aventis, sanofi-aventis Amerique du Nord (collectively, the "Sanofi Parties") and the Issuer, the Sanofi Parties have agreed to vote their respective shares of the Issuer, subject to specified exceptions, in accordance with the recommendation of the Issuer's Board of Directors.

Remarks: Exhibit 24 - Power of Attorney (incorporated herein by reference to Exhibit 24 to Form 4 filed by the Reporting Person with the SEC on February 3, 2016, with respect to Alnylam Pharmaceuticals, Inc.).

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Sanofi 54 RUE LA BOETIE PARIS, I0 75008		X

Signatures
/s/ Alexandra Roger Name: Alexandra Roger Title: Attorney-in-fact		3/11/2020
**Signature of Reporting Person		Date