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Fat Chance: Pharma Loves Diet Drugs, But the FDA Doesn't

The CEO of Arena Pharmaceuticals (ARNA) is excited about the FDA's September 16th meeting at which its new diet drug, Lorcaserin, will be voted on, but the history of the FDA and diet drugs suggests he ought to be anxious. It will be a miracle if Lorcaserin gets a green light.

The FDA isn't exactly reviewing Lorcaserin in a neutral background. The advisory committee will spend the day before it votes looking at Abbott Labs (ABT)'s Meridia, a weight-loss drug that's already on the market but which has been linked to a higher incidence of major cardiovascular adverse events. There will be guilt by association.

The FDA recently rejected Vivus (VVUS)'s Qnexa, another weight-loss drug, and Sanofi-Aventis (SNY)'s Zimulti, yet another obesity pill. It added a liver damage warning to GlaxoSmithKline's Alli, even though the evidence for liver damage is slight.

Lorcaserin's advantage is that its safety profile seems to be the best of a raft of recent attempts to get FDA approval. But it just isn't that effective: It only works in combination with diet and exercize and about half of all patients dropped out of Arena's big clinical trial. The drug only worked for about half of those who took it, if you draw the measure at 5 percent weight loss. It could be that this drug is safe because it doesn't do a heck of a lot.

Arena's management has successfully developed the most likely pill to get approval, but that may not be enough: The FDA just doesn't like diet drugs, and there's little even the best manager can do about that.


Image by Flickr user colros, CC.