FDA Advisory Committee to Discuss Genzyme’s Synvisc-One PMA on Tuesday

Panel Will Consider Clinical Data Supporting Approval and Labeling

Genzyme Corporation (Nasdaq: GENZ) today announced that its Premarket Approval (PMA) application supplement for Synvisc-One™ (hylan G-F 20) will be discussed this Tuesday, December 9th, at a public meeting of the FDA’s Orthopaedic and Rehabilitation Devices Advisory Committee in Gaithersburg, Maryland. The panel is expected to consider the clinical trial results Genzyme submitted to support the approval and labeling of Synvisc-One, a product intended for the relief of pain associated with osteoarthritis of the knee. Genzyme anticipates that the panel will vote on whether the FDA should approve Synvisc-One.

Synvisc-One is a proposed alternative treatment regimen for Genzyme’s Synvisc® (hylan G-F 20), a viscosupplement approved in the United States in 1997 and in use worldwide for more than 16 years. Synvisc-One is administered through a single intra-articular injection, whereas Synvisc is administered as a series of three injections. Synvisc-One contains the same material and total treatment volume as Synvisc but provides the 6 mL of hylan G-F 20 in a single injection. Genzyme is seeking the same indication for Synvisc-One that is currently approved for Synvisc.

“We developed Synvisc-One to provide an innovative treatment alternative that could offer the benefit of viscosupplementation to a broader set of patients by simplifying osteoarthritis pain management,” said Alison Lawton, Genzyme’s senior vice president for global market access. “Our marketing application for Synvisc-One is strong, and we are hopeful that the advisory committee will recommend approval.”

If approved, Synvisc-One would be the only single-injection viscosupplement available in the United States. The product is approved in the European Union and a number of Asian and Latin American countries. Nearly 10,000 patients have been treated with Synvisc-One since it was first approved last year.

Genzyme’s U.S. marketing application is supported by the results from a prospective, randomized, double-blind, placebo-controlled trial that involved 253 patients at 21 sites across Europe. Genzyme incorporated advice from FDA into the design of this study. In this study, a statistically significant improvement in pain from osteoarthritis of the knee was observed over 26 weeks when compared to pain relief for patients receiving saline treatment. This translated into a significant reduction in knee pain, and a greater likelihood of improvement of the overall general joint condition in patients treated with Synvisc-One.

Osteoarthritis is the most common joint disorder in the United States, affecting more than 27 million Americans. There is a spectrum of treatment options to relieve pain from OA ranging from over-the-counter pain relievers and anti-inflammatory drugs such as acetaminophen to invasive surgical procedures. Viscosupplementation, a procedure in which hyaluronic acid is injected into the knee joint to act as a lubricant and a shock absorber, is a well accepted therapy for OA pain that is both comparable to oral therapies, and avoids toxicity and the associated costs of systemic therapy. This innovative procedure is performed on an out-patient basis and requires little recovery time.

FDA action on Genzyme’s marketing application for Synvisc-One is anticipated by December 23, 2008, the Medical Device User Fee Act date. For more information on the panel please visit the FDA web site.

About Synvisc

Synvisc is indicated for the treatment of pain due to osteoarthritis (OA) of the knee in patients who have failed to respond adequately to conservative nonpharmacologic therapy and simple analgesics, for example, acetaminophen. Synvisc is currently approved in Europe and Canada to treat pain due to osteoarthritis in the knee and hip, and also approved in Europe for the ankle and shoulder indications, covering the major joints.

In clinical trials, the most commonly reported adverse events were transient local pain, swelling, and/or effusion in the injected knee. In some cases, these symptoms have been extensive. Other side effects such as rash have been reported rarely. Synvisc is contraindicated in patients with known hypersensitivity to hyaluronan products or patients with infections in or around the knee. Healthcare practitioners should exercise caution when using Synvisc in patients allergic to avian proteins, feathers, or egg products; who have evidence of venous or lymphatic stasis in the leg to be treated; or who have severe inflammation in the knee joint to be treated. Patients should be advised to avoid strenuous or prolonged weight-bearing activities after treatment. Strict adherence to aseptic technique must be followed to avoid joint infection. The safety and effectiveness of Synvisc in children and in pregnant or lactating women have not been established. It is unknown whether Synvisc is excreted in human milk.

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 10,000 employees in locations spanning the globe and 2007 revenues of $3.8 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.

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 immune disease, and diagnostic testing. 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.

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.

This press release contains forward-looking statements about Genzyme’s future plans and strategies, including statements about: the topics the FDA Advisory Committee is expected to consider; whether a single-injection regimen of Synvisc will provide the benefits of viscosupplementation to a broader set of patients; Genzyme’s hope that the FDA approves its marketing application for Synvisc-One; and its expectation that FDA action will be taken by December 23, 2008. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others: whether the FDA determines that Synvisc-One can appropriately be approved for marketing in the US by its MDUFA date, the actual focus of the panel on December 9th, 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 fiscal quarter ended September 30, 2008. 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.