Company and Wall Street disagree over trial results of diet drug lorcaserin

If you only read the press release issued by Arena Pharmaceuticals you would think the results of BLOSSOM, the highly anticipated phase 3 trial of the diet drug locaserin, were overwhelmingly positive. But Wall Street has a different view of the trial and drove the stock price of the company down more than 10%. Update: By Friday afternoon Wall Street appeared to change its mind. By the end of the day the stock was up 5.5%.

BLOSSOM randomized 4,000 obese or overweight patients to locaserin 10 mg (once or twice daily) or placebo. 47.25% of locaserin patients lost 5% of their weight, versus 25% taking placebo. According to Arena, “this result satisfies the efficacy benchmark in the most recent FDA draft guidance which provides that a weight-management product can be considered effective if the proportion of patients who lose at least 5% of baseline body weight in the active-product group is at least 35%, is approximately double the proportion in the placebo-treated group, and the difference between groups is statistically significant.” CardioBrief is unaware of a precise FDA definition of the word “approximately.”

But the trial did not meet a second, alternate FDA efficacy guideline, which requires that the difference in mean weight loss between the active-product and placebo-treated groups is at least 5%.

An Associated Press story quotes Lazard Capital Markets analyst Terence Flynn as saying the results “appear to be on border of the criteria recommended by the FDA.” The analyst also notes that the weight loss appears to be smaller than that reported in recent clinical trials of two other weight loss drugs under development.

Click to read stories from the Associated Press, Bloomberg News, or Dow Jones newswires.

Click here to read our story on Qnexa, the combination of phentermine and topiramate from Vivus.

Click here to download the press release from Arena.


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