FDA panel backs Benlysta but spurs new marketing worries

Beating back some deep-seated concerns regarding the efficacy and safety of Human Genome Science's ($HGSI) Benlysta, a solid majority of an FDA advisory panel voted to endorse the therapy and recommend that the agency approve it as the first new lupus drug in half a century.

At least one of the panel members, Dr. David Blumenthal, rattled supporters of the drug with a dour assessment of Benlysta's efficacy. The FDA staff had earlier noted that the data on the drug appeared to support a case for only marginal efficacy. And there were particular concerns regarding the efficacy among U.S. patients and African Americans. But most of the experts on the panel appeared eager to give lupus patients access to something that could offer hope of ameliorating the symptoms of the disease. And that sentiment clearly helped win the day for HGS, which has a potential blockbuster on its hands. HGS is partnered with GlaxoSmithKline ($GSK), but will split revenue on the drug, which could exceed $2 billion a year.

At the end of the day the panelists voted 13 to 2 that the drug should be on the market. But the lopsided vote failed to elicit many cheers among analysts, several of whom were concerned that the sharp discussion focused on the drug's questionable efficacy would blunt demand for the drug even as a potentially tough label would limit market potential.

"The label will likely have noticeable restrictions and thin efficacy is already drawing a mixed reception from rheumatologists. We are concerned about the long-term sales potential given (1) modest benefit, (2) poorer activity in U.S. pts than we originally expected, and (3) now more restricted label," wrote Citi biotech analyst Yaron Werber, who cut his peak sales forecast by a billion dollars a year as a result. HGSI shares slid seven percent in early trading today as marketing worries mounted.

HGS, though, has had plenty of support for its drug from disease groups. "I really do think the drug is efficacious," noted Sandra Raymond, president & CEO of the Lupus Foundation of America. "What I'm hearing in terms of efficacy is pretty strong." A final decision from the FDA should arrive by December 9.

- here's the Reuters story on the vote
- here's the report from TheStreet this morning