Positive Synvisc Data Presented at European Conference

Results Show Superiority of Synvisc in Pain Relief and Patient Satisfaction

June 23, 2006, Genzyme Corp. (Nasdaq: GENZ) today announced that data were presented from an independent clinical study examining the effectiveness, functional outcome and patient satisfaction following injections with Synvisc® (hylan G-F 20) and Hyalgan® (sodium hyaluronate) in patients with osteoarthritis (OA) of the knee. The investigator-initiated study was conducted in a leading university teaching hospital in the United Kingdom and finds that Synvisc is superior to Hyalgan in magnitude and duration of pain relief, functional improvement and patient satisfaction. These data were presented this afternoon at the annual congress of the European League Against Rheumatism (EULAR) meeting in Amsterdam, The Netherlands.

Study Results

In this controlled, prospective study, 348 patients with osteoarthritis of the knee were randomized to receive intra-articular injections of either Synvisc or Hyalgan. All patients were given the recommended doses (3 weekly injections of Synvisc or 5 weekly injections of Hyalgan) which were administered by the same physician. All patients were reviewed by independent assessors who were blinded for the treatment at pre-injection, six weeks, three and six months, and yearly thereafter.

As reported at the conference, both treatment groups experienced pain reduction. However, patients receiving Synvisc experienced a greater magnitude of pain relief which occurred earlier and lasted longer. Similarly, the functional outcome and physical activity scores were significantly better in the Synvisc group throughout the study.

“Our study demonstrated that the pain relief obtained in patients treated with Synvisc was superior to that of Hyalgan,” stated Raghu Raman, M.D., orthopaedic surgeon at the Hull Royal Infirmary in Hull, United Kingdom, and the principal investigator of the study. “Patients treated with Synvisc also demonstrated an early increase in activity levels and, from these data, it appears both the clinical effectiveness and general patient satisfaction are better among patients who received Synvisc.”

Richard Polisson, M.D., senior vice president of clinical research at Genzyme, stated that these findings are significant not only because of the noted differences in outcomes between the two products, but also because of the well designed nature of the study and the completely independent status of the investigator.

“We are very pleased that this clinical study clearly shows that Synvisc is highly effective in treating the symptoms of osteoarthritis of the knee,” said Polisson. “These data now provide an answer to the questions that the clinical community has asked about products in this class and confirms what we have always believed - that Synvisc delivers a greater magnitude and duration of pain relief and greater improvement in function than Hyalgan, and should be viewed differently from other viscosupplements.”
Additional Study Findings

Both treatments were well tolerated, however, a local inflammatory reaction was observed in one patient treated with Synvisc. Data from the study also show that there was a local increase in knee pain in one patient who received Synvisc, which settled by four weeks.

A Market Leader Powered by Clinical Benefit

Synvisc is marketed in more than 60 countries and has been used to treat more than 3 million people. Because market penetration is still in the early stages, there is much room for future growth. In 2004 and 2005, two meta-analyses affirmed the clinical benefit of Synvisc and its class of viscosupplements. The studies were conducted using research methodologies that provide physicians and payers with tools to evaluate new treatments using an evidence-based approach. In addition to its efficacy in relieving pain, Synvisc, as a non-systemic treatment, has the advantage of avoiding the side effects associated with some non-steroidal anti-inflammatory drugs including the COX-2 inhibitors.

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 osteroarthritis in both the knee and hip.

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 Corporation

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. This year marks the 25th anniversary of Genzyme’s founding. Since 1981, the company has grown from a small start-up to a diversified enterprise with more than 8,000 employees in locations spanning the globe and 2005 revenues of $2.7 billion. Genzyme has been 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 more than 80 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 diseases, and diagnostic testing. Genzyme’s commitment to innovation continues today with a substantial development program focused on these fields, as well as heart disease and other areas of unmet medical need.

Genzyme® and Synvisc® are registered trademarks of Genzyme Corporation. Hyalgan® is a registered trademark of Sanofi Aventis. All rights reserved.

Contact Information

Maria Cantor

Media Contact

Genzyme Corp.

Contact via E-mail