Genzyme Corp. has 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 programme 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, an investigational combined-dose regimen of Synvisc (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 randomised 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 programme 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 analyse 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."