Genzyme Receives FDA Response Letter on Synvisc-One™

Date: November 13, 2007

Approval in U.S. to be Delayed

Genzyme Corp. (Nasdaq: GENZ) announced today that it has received a letter from the U.S. Food and Drug Administration requesting additional analyses and data regarding the marketing application for Synvisc-One™ in the United States. The company now expects that approval of the next-generation Synvisc^® (hylan G-F 20) to be delayed in the U.S. until at least the second half of 2008.

Synvisc-One is a single treatment of Synvisc that is intended to provide up to six months of pain relief from osteoarthritis (OA) of the knee. Genzyme believes that Synvisc-One will simplify osteoarthritis pain management and provide added patient convenience, while reducing the overall cost of therapy and offering a treatment option that will expand the benefits of viscosupplementation to a broader number of patients.

Genzyme has filed for approval of Synvisc-One in Europe and, if granted a CE mark there, will pursue marketing approvals in wider geographies in Asia and Latin America.

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 more than 9,500 employees in locations spanning the globe and 2006 revenues of $3.2 billion. In 2007, Genzyme was chosen to receive the National Medal of Technology, the highest honor awarded by the President of the United States for technological innovation. In 2006 and 2007, Genzyme was selected by FORTUNE as one of the “100 Best Companies to Work for” in the United States.

With many established products and services helping patients in nearly 90 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 diagnostic testing. Genzyme's commitment to innovation continues today with a substantial development program focused on these fields, as well as immune disease, infectious disease, and other areas of unmet medicalneed.

This press release contains forward-looking statements, including Genzyme’s expectation for receipt of US marketing approval of Synvisc-One and the revised timing thereof, its belief that a single-injection regimen of Synvisc will simplify pain management, provide additional patient convenience, reduce costs and expand the viscosupplementation market, and Genzyme’s plans to pursue marketing approvals in additional jurisdictions. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected. These risks and uncertainties include, among others, Genzyme’s ability to adequately respond to the questions raised by the FDA and to do so in a timely fashion, the extent to which the FDA determines that Synvisc-One can appropriately be approved for marketing in the US, the extent to which the government and private insurers recognize the benefits of Synvisc-One and maintain or otherwise implement reimbursement policies that reflect these benefits, and the risks and uncertainties described in reports filed by Genzyme with the U.S. Securities and Exchange Commission, including without limitation the factors discussed under the caption "Risk Factors" in Genzyme's Quarterly Report on Form 10-Q for the quarter ended September 30, 2007. We caution investors not to place undue reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this press release, and we undertake no obligation to update or revise the statements.

Genzyme^® and Synvisc^® are registered trademarks and Synvisc-One^™ is a trademark of Genzyme Corporation. All rights reserved.

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.

Términos y Condiciones de Uso | Política de Privacidad | © 2008 Genzyme Corporation. Todos los Derechos Reservados.