Arena shares dive on debate over obesity data

Shares of Arena Pharmaceuticals shed 20 percent of their value this morning after patients enrolled in a two-year study of its obesity drug failed to shed enough weight to impress investors.

Arena's researchers declared that lorcaserin met all its primary endpoints with an average weight loss of 5.8 percent of body weight after 12 months of treatment. The placebo group lost 2.2 percent of their body weight, leaving analysts shaking their head over the 3.6 percentage point difference. The FDA wants to see a 5 percentage point gap between the two.

Arena, though, countered by saying that 48 percent of the lorcaserin group lost more than 5 percent of their body weight, compared to 20 percent in the placebo group who matched that performance. And that was key.

Cowen & Co. analyst Philip Nadeau thought that the numbers bode well for Arena. "They meet the FDA criteria for approvability," he told Dow Jones.

- see Arena release
- check out the story from the Wall Street Journal

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