SC 14D9/A

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14D-9

SOLICITATION/RECOMMENDATION STATEMENT
PURSUANT TO SECTION 14(d)(4) OF THE
SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 12)

GENZYME CORPORATION

(Name of Subject Company)

GENZYME CORPORATION

(Name of Person(s) Filing Statement)

Common Stock, par value $0.01 per share
(Title of Class of Securities)

372917104
(CUSIP Number of Common Stock)

Peter Wirth
Executive Vice President
Genzyme Corporation
500 Kendall Street
Cambridge, Massachusetts 02142
(617) 252-7500
(Name, Address and Telephone Number of Person Authorized to Receive Notices
and Communications on Behalf of the Person(s) Filing Statement)

With copies to:

Paul M. Kinsella	Andrew R. Brownstein
Ropes & Gray LLP	Wachtell, Lipton, Rosen & Katz
Prudential Tower	51 West 52nd St
800 Boylston Street	New York, New York 10019
Boston, Massachusetts 02199	(212) 403-1000
(617) 951-7000

o  Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

This Amendment No. 12 amends and supplements the Solicitation/Recommendation Statement on Schedule 14D-9 originally filed by Genzyme Corporation, a Massachusetts corporation (the “Company” or “Genzyme”), with the Securities and Exchange Commission (the “SEC”) on October 7, 2010 (as previously amended, the “Schedule 14D-9”), relating to the unsolicited tender offer by GC Merger Corp., a Massachusetts corporation (“Offeror”) and wholly-owned subsidiary of Sanofi-Aventis, a French société anonyme (“Sanofi”), to purchase all of the outstanding shares of the Company’s common stock, par value $.01 per share (the “Shares”), at a purchase price of $69.00 per Share (the “Offer Price”), net to the selling shareholders in cash, without interest thereon and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated October 4, 2010 (the “Offer to Purchase”), and in the related Letter of Transmittal (which, together with the Offer to Purchase, constitutes the “Offer”), included as Exhibits (a)(1)(A) and (a)(1)(B) to the Tender Offer Statement on Schedule TO (as amended or supplemented from time to time, the “Schedule TO”) filed by Sanofi and Offeror with the SEC on October 4, 2010.

Item 9. Exhibits.

Item 9 of the Schedule 14D-9 is hereby amended and supplemented by adding the following thereto:

Exhibit No.	Description
(a)(27)	Press release issued by Genzyme, dated December 13, 2010.

SIGNATURE

     After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: December 13, 2010	GENZYME CORPORATION
	By:	/s/ Thomas J. DesRosier
		Name:	Thomas J. DesRosier
		Title:	Senior Vice President, General Counsel and Chief Legal Officer

EX-99.A.27

Exhibit (a)(27)

For Immediate Release	Media Contact:	Investor Contact:
December 13, 2010	Bo Piela	Patrick Flanigan
	(617) 768-6579	(617) 768-6563

Genzyme to Hold Investor Event on Alemtuzumab

Cambridge, MA — Genzyme Corp. (NASDAQ: GENZ) announced today that it will hold an Analyst and Investor meeting in New York on December 20, 2010, focused specifically on the commercial potential of alemtuzumab for multiple sclerosis. The event will be webcast live from 1:00 p.m.-3:00 p.m. Eastern on the investor events section of www.genzyme.com. The event is part of Genzyme’s ongoing program to communicate with shareholders regarding the intrinsic value of the company.

About Genzyme

One of the world’s leading biotechnology companies, Genzyme is dedicated to making a major positive impact on the lives of people with serious diseases. Since 1981, the company has grown from a small start-up to a diversified enterprise with approximately 10,000 employees in locations spanning the globe and 2009 revenues of $4.5 billion. In 2010, Genzyme was named to the Fortune 500.

With many established products and services helping patients in 100 countries, Genzyme is a leader in the effort to develop and apply the most advanced technologies in the life sciences. The company’s products and services are focused on rare inherited disorders, kidney disease, orthopaedics, cancer, transplant, and immune disease. Genzyme’s commitment to innovation continues today with a substantial development program focused on these fields, as well as cardiovascular disease, neurodegenerative diseases, and other areas of unmet medical need.

Important Information

Genzyme has filed with the Securities and Exchange Commission a Solicitation/Recommendation Statement on Schedule 14D-9 relating to the tender offer by Sanofi-Aventis. Genzyme shareholders are advised to read the company’s Solicitation/Recommendation Statement on Schedule 14D-9 because it contains important information. Shareholders may obtain a free copy of the Solicitation/Recommendation Statement on Schedule 14D-9, as well as any other documents filed by Genzyme in connection with the tender offer, free of charge at the SEC’s website at http://www.sec.gov. In addition, investors can obtain free copies of these documents from Genzyme by directing a request to Genzyme at 500 Kendall Street, Cambridge, MA 02142, Attention: Shareholder Relations Department, or by calling 617-252-7500 and asking for the Shareholder Relations Department.

Genzyme’s press releases and other company information are available at www.genzyme.com and by calling Genzyme’s investor information line at 1-800-905-4369 within the United States or 1-678-999-4572 outside the United States.