Regeneron Pharmaceuticals, Inc. 777 Old Saw Mill River Road Tarrytown, NY 10591-6707 Phone 914 847 7000 www.regeneron.com

Via EDGAR

May 4, 2016

Mr. Jim B. Rosenberg

Senior Assistant Chief Accountant

Office of Healthcare and Insurance

U.S. Securities and Exchange Commission

Division of Corporation Finance

100 F Street, NE

Washington, D.C. 20549

Re:	Regeneron Pharmaceuticals, Inc.
	Form 10-K for the Fiscal Year Ended December 31, 2015
	Filed February 11, 2016
	Form 8-K dated February 9, 2016
	Filed February 9, 2016
	File No. 000-19034

Dear Mr. Rosenberg:

Regeneron Pharmaceuticals, Inc. (the "Company") acknowledges receipt of the letter dated May 2, 2016 provided by the staff of the Securities and Exchange Commission (the "Staff") with respect to the above-referenced Form 10-K and Form 8-K. The Company subsequently corresponded with Bonnie Baynes of the Staff on May 3, 2016, who kindly granted the Company’s request for a five business day extension. Accordingly, the Company plans to provide its response to the letter on or before May 23, 2016.

If you have any questions regarding the foregoing, please contact me at (914) 847-7270.

Very truly yours,

REGENERON PHARMACEUTICALS, INC.

/s/ Robert E. Landry

Robert E. Landry

Senior Vice President, Finance and Chief Financial Officer

cc: Bonnie Baynes, Staff Accountant