Sanofi — Director's Dealing 2010

Oct 14, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: REGENERON PHARMACEUTICALS INC (REGN)
CIK: 0000872589
Period of Report: 2010-10-13

Reporting Person: SANOFI-AVENTIS (10% Owner)
Reporting Person: Sanofi-Aventis Amerique du Nord S.N.C. (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-10-13	Common stock, $.001 par value	P	1017401	$28.00	Acquired	15816953	Indirect

Footnotes

F1: 13,017,401 shares are held directly by sanofi-aventis Amerique du Nord and 2,799,552 of the shares are held directly by Aventis Pharmaceuticals Inc. Sanofi-aventis Amerique du Nord is indirectly wholly owned by sanofi-aventis and Aventis Pharmaceuticals Inc., an indirectly wholly-owned subsidiary of sanofi-aventis, is controlled by sanofi-aventis Amerique du Nord. Accordingly, sanofi-aventis can be deemed to share voting and dispositive power over the shares held directly by sanofi-aventis Amerique du Nord and Aventis Pharmaceuticals Inc. Similarly, sanofi-aventis Amerique du Nord can be deemed to share voting and dispositive power over the shares held directly by Aventis Pharmaceuticals Inc.