Drug: Qnexa
Company: Vivus
PDUFA date: Oct. 28
Peak sales: Who knows?

One of the hottest late-stage development races in biotech is being played out among three public companies--Vivus, Arena and Orexigen--which are laying it all on the line. Unfortunately, they've helped illustrate just why so many Big Pharma companies fear to tread in a development arena where the safety bar is placed very, very high.

Just how high became evident when an expert FDA advisory panel took a close look at some promising one-year safety and efficacy data on Qnexa and then voted 10 to six against a recommendation. There were some big fears that the diet drug could trigger cardiovascular and other side effects which the one-year data wouldn't pick up on. And with the drug designed as an on-going therapy to control weight over an indefinite period, that was a risk they weren't willing to ignore.

Vivus wasn't rolling over, though. Soon after the panel voted the company released solid two-year data with a somewhat improved side effect profile and continued weight-loss well ahead of FDA guidelines for an approval. At a high dose, patients lost an average of 11.4 percent of their weight. That translates to 26 pounds. So far, so good. There's considerable disagreement, though, that the agency will overrule their experts and approve the drug. That could mean a complete response letter conceding approvability but laying out some requirements for continued study. If that means a new trial to examine, say, cardiovascular safety, the drug would be seriously delayed. But not dead.

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