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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5
	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) 1/11/2017
(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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	1/11/2017		P		1592 ⁽¹⁾ ⁽²⁾	A	$362.4664 ⁽¹⁾ ⁽³⁾	23419988	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		6546 ⁽¹⁾ ⁽²⁾	A	$363.3534 ⁽¹⁾ ⁽⁵⁾	23426534	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		13226 ⁽¹⁾ ⁽²⁾	A	$364.3224 ⁽¹⁾ ⁽⁶⁾	23439760	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		19858 ⁽¹⁾ ⁽²⁾	A	$365.2018 ⁽¹⁾ ⁽⁷⁾	23459618	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		3979 ⁽¹⁾ ⁽²⁾	A	$366.0528 ⁽¹⁾ ⁽⁸⁾	23463597	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		1986 ⁽¹⁾ ⁽²⁾	A	$367.2911 ⁽¹⁾ ⁽⁹⁾	23465583	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		2336 ⁽¹⁾ ⁽²⁾	A	$368.3472 ⁽¹⁾ ⁽¹⁰⁾	23467919	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		2517 ⁽¹⁾ ⁽²⁾	A	$369.3 ⁽¹⁾ ⁽¹¹⁾	23470436	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		900 ⁽¹⁾ ⁽²⁾	A	$370.1789 ⁽¹⁾ ⁽¹²⁾	23471336	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		1259 ⁽¹⁾ ⁽²⁾	A	$371.5346 ⁽¹⁾ ⁽¹³⁾	23472595	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		2675 ⁽¹⁾ ⁽²⁾	A	$372.8741 ⁽¹⁾ ⁽¹⁴⁾	23475270	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		2784 ⁽¹⁾ ⁽²⁾	A	$373.9018 ⁽¹⁾ ⁽¹⁵⁾	23478054	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		3830 ⁽¹⁾ ⁽²⁾	A	$374.5922 ⁽¹⁾ ⁽¹⁶⁾	23481884	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		3016 ⁽¹⁾ ⁽²⁾	A	$375.8789 ⁽¹⁾ ⁽¹⁷⁾	23484900	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		3851 ⁽¹⁾ ⁽²⁾	A	$376.7488 ⁽¹⁾ ⁽¹⁸⁾	23488751	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		5313 ⁽¹⁾ ⁽²⁾	A	$377.8368 ⁽¹⁾ ⁽¹⁹⁾	23494064	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		9520 ⁽¹⁾ ⁽²⁾	A	$378.7635 ⁽¹⁾ ⁽²⁰⁾	23503584	I	See note ⁽⁴⁾
Common Stock	1/11/2017		P		2110 ⁽¹⁾ ⁽²⁾	A	$379.5636 ⁽¹⁾ ⁽²¹⁾	23505694	I	See note ⁽⁴⁾

*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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:
( 1)	The number of securities reported represents an aggregate number of shares purchased in multiple market transactions over a range of purchase prices. The price reported represents the weighted average price per share. The Reporting Person undertakes to provide the staff of the SEC, the Issuer, or a stockholder of the Issuer, upon request, the number of shares purchased by the Reporting Person at each separate price within the range.
( 2)	Represents shares acquired directly by sanofi-aventis Amerique du Nord ("SAAN").
( 3)	Purchase prices range from $361.76 to $362.71 per share, inclusive.
( 4)	Indirectly owned through (a) SAAN, a direct, wholly-owned subsidiary of Sanofi, and (b) Aventis Pharmaceuticals Inc. ("Aventis"), an indirect, wholly-owned subsidiary of SAAN. After giving effect to all acquisitions reported on this Form 4, the number of shares beneficially owned directly by SAAN and Aventis was 20,706,142 shares and 2,799,552 shares, respectively. Pursuant to the Amended and Restated Investor Agreement, dated as of January 11, 2014, by and among Sanofi, SAAN, sanofi-aventis US LLC, Aventis (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.
( 5)	Purchase prices range from $362.80 to $363.79 per share, inclusive.
( 6)	Purchase prices range from $363.80 to $364.77 per share, inclusive.
( 7)	Purchase prices range from $364.80 to $365.79 per share, inclusive.
( 8)	Purchase prices range from $365.80 to $366.73 per share, inclusive.
( 9)	Purchase prices range from $366.83 to $367.81 per share, inclusive.
( 10)	Purchase prices range from $367.84 to $368.78 per share, inclusive.
( 11)	Purchase prices range from $368.84 to $369.79 per share, inclusive.
( 12)	Purchase prices range from $369.87 to $370.59 per share, inclusive.
( 13)	Purchase prices range from $371.05 to $372.02 per share, inclusive.
( 14)	Purchase prices range from $372.29 to $373.27 per share, inclusive.
( 15)	Purchase prices range from $373.30 to $374.28 per share, inclusive.
( 16)	Purchase prices range from $374.31 to $375.24 per share, inclusive.
( 17)	Purchase prices range from $375.36 to $376.34 per share, inclusive.
( 18)	Purchase prices range from $376.36 to $377.34 per share, inclusive.
( 19)	Purchase prices range from $377.36 to $378.35 per share, inclusive.
( 20)	Purchase prices range from $378.37 to $379.36 per share, inclusive.
( 21)	Purchase prices range from $379.38 to $379.80 per share, inclusive.

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

Signatures
/s/ Alexandra Roger, attorney-in-fact		1/13/2017
^** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.