Genzyme Corporation's Hylastan Misses Goal in Arthritis Trial CAMBRIDGE, Mass., July 5 -- Genzyme Corp. today announced top-line results from a pivotal study investigating the safety and efficacy of hylastan in treating pain in patients with osteoarthritis (OA) of the knee. Hylastan is being developed within Genzyme's program to introduce a viscosupplementation product that can be delivered through a single knee injection. The goal of this effort is to simplify OA pain management, reduce the overall cost of therapy and advance a treatment option that may expand the benefits of viscosupplementation to a broader number of patients. Genzyme's development program also includes Synvisc-One(TM), an investigational combined-dose regimen of SynviscÂ® (hylan G-F 20) provided in a single injection, which the company is currently seeking to market in the United States and Europe. Genzyme has submitted an application to the FDA for Synvisc-One, and later this month will apply for a CE Mark to introduce Synvisc-One in Europe. Regulatory action on both applications is expected this year. Results from the successful pivotal study of Synvisc-One were presented last month at the Annual European Congress of Rheumatology. The pivotal trial of hylastan was a double-blind, active-control study involving nearly 400 patients with osteoarthritis of the knee enrolled at 27 sites in North America and Europe. Patients were randomized to receive two intra-articular injections of hylastan delivered two weeks apart, a single injection of hylastan, or an injection of a corticosteroid. Patients were evaluated for 26 weeks following treatment. Results showed a statistically significant and clinically meaningful reduction in knee pain compared to baseline for each of the three treatment arms. However, the difference in pain reduction between patients treated with hylastan and patients treated with a steroid was not significant, and the trial did not meet its primary endpoint of demonstrating that hylastan provides superior pain relief to steroids. The safety profile of the three treatment arms appeared to be comparable in the preliminary analysis of the study results. "We structured our development program in a way that provided us with several chances to reach our goal of introducing a single-injection product," said Ann Merrifield, president of Genzyme Biosurgery, the business unit that manufactures and markets Synvisc. "It is now clear that we will focus our efforts on bringing Synvisc-One to the market. We are confident that simplifying the treatment process will encourage a greater number of physicians and patients to seek the benefits of viscosupplementation to help manage OA knee pain. We will continue to analyze the findings from the hylastan study to determine how this product fits into our longer-range strategy, as we continue to invest in bringing innovation to this field." 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 9,000 employees in locations spanning the globe and 2006 revenues of $3.2 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 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 medical need. This press release contains forward-looking statements, including the statements regarding whether and when Synvisc-One obtains marketing approval in the US and the timing of a regulatory filing for Synvisc-One in Europe. 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, the extent to which the US Food and Drug Administration determines that Synvisc- One can appropriately be approved for marketing in the US, our ability to prepare the necessary regulatory filing for Europe in a timely fashion and the risks and uncertainties described in reports filed by Genzyme with the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended, including without limitation the information under the heading "Risk Factors" in the Management's Discussion and Analysis of Financial Condition and Results of Operations section of the Genzyme Quarterly Report on Form 10-Q for the quarter ending March 31, 2007. Genzyme cautions investors not to place substantial reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this press release, and Genzyme undertakes no obligation to update or revise the statements. GenzymeÂ® and SynviscÂ® are registered trademarks and Synvisc-One(TM) is a trademark of Genzyme Corporation. All rights reserved.