Vertex shares jump on FDA findings

By Robert Weisman, Globe Staff

A proposed drug developed by Vertex Pharmaceuticals Inc. cures more patients with the hepatitis C virus in less time than existing therapies, according to a briefing document filed today by Food and Drug Administration staffers who reviewed the new drug application.

Shares of Cambridge-based Vertex vaulted 12.8 percent to $54.20 on the Nasdaq exchange at 11:35 p.m., a gain of $6.03.

The drug, called telaprevir, would be used in combination with two current therapies. Together, the drug "cocktail" proved more effective in late-stage clinical trials than the older drugs by themselves, the briefing paper said. The document was prepared in advance of a day-long hearing Thursday by an FDA advisory committee that will recommend whether the agency should approve the new drug.

Tomorrow the same FDA advisory committee will consider a rival hepatitis C treatment, boceprevir, developed by Merck & Co. Both drugs act to inhibit the protease enzyme that enables the virus to reproduce, and both target a market projected by some securities analysts to exceed $2 billion annually this year and in 2012.

While the FDA document didn't tip its hand on whether the advisory committee will recommend in favor of telaprevir, the drug's approval is widely anticipated by industry analysts, doctors, and hepatitis C patients. The FDA document said telaprevir, used in the regimen Vertex is proposing, cured 79 percent of patients in a clinical trial -- higher than the 75 percent cure rate the company reported to the agency last May.