San Diego-based Arena Pharmaceuticals this morning released the much-anticipated clinical trial data on its obesity drug lorcaserin. The data was basically the same than data in a smaller study it released earlier this year. But that didn’t stop its stock price from going on a wild ride.

Data from the 4,008-person study showed the drug meeting one of two weight-loss benchmarks established by the U.S. Food and Drug Administration. Just more than 47 percent of patients taking the pill lost 5 percent or more of their body weight compared to 25 percent of patients who were on a placebo. That meets the FDA benchmark that requires weight loss among patients taking an obesity drug to be approximately double that of a placebo.

That was the good news. The bad news is that the drug didn’t meet a second FDA benchmark. Patients’ average weight loss after one year was 5.9 percent, which was 3.1 percentage points more than patients taking a placebo. The FDA benchmark requires at least a 5 percent difference between the drug and the placebo. The agency requires one of those two benchmarks to be met before it will consider approving the drug.

Company officials said this morning that they will submit lorcaserin for FDA approval in December.

The results were very similar to the results of the company’s study in March, which caused its share price to drop precipitously and analysts to accuse Arena CEO Jack Lief of overhyping lorcaserin.

Arena’s stock price shot up from $4.91 to over $6 in after-hours trading Thursday as the market anticipated the results. Shares slid back this morning and are now trading at $5.53, 12.6 percent higher than yesterday’s close.

Arena is among three companies currently vying for FDA approval for new weight loss drugs. The others are La Jolla-based Orexigen Therapeutics and Bay Area-based Vivus. Stock in Orexigen, which in July posted trial results for its obesity drug Contrave that were similar to Arena’s results, is down 1 percent. Shares in Vivus, which last week posted trial results for its drug, Qnexa, that were better than both lorcaserin’s and Contrave’s, are up nearly 8 percent.

Expect an update later after I make calls to analysts and try to get in touch with Lief. Meanwhile, you can check out this Bloomberg story for more details on the release.


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