Genzyme Corp. is looking to expand the reach of its leading osteoarthritis product after beginning a pivotal trial in an area beyond its already-approved indication.

The Cambridge, Mass.-based company started patient treatment to evaluate the ability of Synvisc (hylan G-F 20) in treating pain due to osteoarthritis of the hip. The product already holds the top sales spot in the U.S. and Canada for pain that results from osteoarthritis of the knee, Genzyme said, projecting full-year worldwide sales in that indication to range between $262 million and $284 million.

Those figures make it the company's third-largest product, and such forecasts could grow should Synvisc succeed in the trial and gain an expanded U.S. label. Genzyme said the U.S. has about 25 million osteoarthritis patients, with about half suffering from knee pain.

Genzyme officials could not be reached for comment.

The viscosupplementation product is approved in Europe and Canada for both osteoarthritis of the hip and knee.

The primary objective of the study, which is expected to enroll 300 patients at 30 U.S. sites, is to determine the safety and efficacy of two intra-articular Synvisc injections for patients with mild to moderate primary osteoarthritis of the hip. Investigators will follow the patients every few weeks after injection until the study concludes.

Genzyme's broader plans for Synvisc, which is administered in three injections over a 15-day period, include two European trials in patients with pain due to osteoarthritis of the ankle and shoulder. The studies are expected to begin by the end of the year.

The product stems from the company's biosurgery division, which also received positive news related to an internally developed cosmetic dermal filler. Along with partner Inamed Corp., of Santa Barbara, Calif., Genzyme said the FDA's General and Plastic Surgery Devices Panel voted to recommend approval with certain conditions of its pre-market approval application to market Hylaform (Hylan-B Gel), a hyaluronic acid-based product for soft-tissue contour deficiencies such as wrinkles.

Its stock (NASDAQ:GENZ) gained $2.46 Monday to close at $46.49.