Washington Editor

A federal panel of advisers Tuesday voted unanimously in favor of approval of Genzyme Corp.'s Synvisc-One, an investigational injectable product intended to relieve pain associated with osteoarthritis of the knee in patients who do not respond to simple analgesics, such as acetaminophen.

The vote from the FDA's Orthopaedic and Rehabilitation Devices Advisory Committee was 5 to 0.

While the panel's backing of Synvisc-One was important for Genzyme's shares, it was not a crucial event for the company, said Leerink Swann analyst Bill Tanner.

Shares of the Cambridge, Mass.-based firm (NASDAQ:GENZ) rose $1.93 Wednesday, to close at $65.19.

The drug is a single-injection version of Genzyme's Synvisc (hylan G-F 20), a viscosupplement approved in the U.S. in 1997, which is administered as a series of three injections.

Synvisc-One already has been approved in the European Union and a number of Asian and Latin American countries, with nearly 10,000 patients receiving the drug since last year, Genzyme said.

However, FDA drug reviewers said in briefing documents that there may be a need for Genzyme to conduct a postapproval study of Synvisc-One.

Regulators had noted that the clinical study supporting the product's U.S. application was conducted in Europe with a limited population.

But even if the FDA requires Genzyme to conduct any postapproval studies of Synvisc-One and the review period is extended beyond Dec. 23, the Prescription Drug User Fee Act (PDUFA) action date, Leerink's Tanner said he doubted such a delay would impact Genzyme's 2009 non-GAAP earnings per share guidance of $4.70.

The most important factor affecting the company's future revenues, he noted, is approval of the 2,000 L bioreactor scale version of Myozyme (alglucosidase alfa), which currently is approved in the U.S. at the 160 L bioreactor scale to treat all forms of Pompe disease, a rare, potentially life-threatening neuromuscular disorder.

Regulators last month informed the company that it was delaying the 2,000 L scale product's PDUFA date from Nov. 29 to Feb. 28, 2009, to give the FDA time to complete its review of Genzyme's risk evaluation and mitigation strategy plan for the drug and for the agency and the company to work out the details of a postapproval verification study.

Genzyme said on Nov. 17 that the agency had agreed to an accelerated approval process for Myozyme 2,000 L scale for late-onset Pompe disease, which was recommended by a panel of outside experts in October. (See BioWorld Today, Oct. 22, 2008.)

With the positive vote Tuesday by the FDA advisers for Synvisc-One, said analyst Christopher Raymond, of Robert W. Baird & Co., the chances of a timely approval of that product are now greater.

And, he added, considering the panel's discussion indicating Synvisc-One is effective for treating osteoarthritis, approval by the Dec. 23 PDUFA date is more likely.

The FDA is not bound by the recommendations rendered by its outside advisory panels, but generally follows their advice.

Tanner noted that Genzyme has captured nearly half of the U.S. viscosupplement market share with Synvisc.

"We believe it logical that a single-injection hyaluronic acid preparation such as Synvisc-One could increase the company's market share," he said, noting that competing agents, such as Ferring Pharmaceuticals Inc.'s Euflexxa, Sanofi-Aventis Group's Hyalgan, DePuy Mitek Inc.'s Orthovisc and Smith & Nephew's Supartz, are recommended to be injected weekly for three to five weeks, depending on the specific product.

Genzyme reported third-quarter sales of Synvisc and Synvisc-One of $67.5 million, a 10 percent increase from the $61.2 million reported at the same period last year. The company said that growth was driven primarily by the increasing strength of Synvisc in the U.S. market.

Tanner noted that the high, low and consensus revenue expectations for the Synvisc franchise are $355 million, $267 million and $307 million, respectively. He set his estimate at $349 million.