Will Orexigen's Diet Pill Survive an FDA Panel?

| About: Orexigen Therapeutics, (OREX)

Twice this year, an FDA advisory committee refused to recommend new diet pills for marketing approval. First, Vivus (NASDAQ:VVUS) failed to win approval for its Qnexa drug and the same fate then met Arena Pharmaceuticals (NASDAQ:ARNA) and its Lorqess med (see here and here). Next Tuesday, however, the third in this controversial trifecta will make an appearance - Orexigen Therapeutics (NASDAQ:OREX) and its Contrave pill. Will the outcome be different?

The FDA briefing documents point out some safety issues, but there do not appear to be any great surprises either, suggesting that, well, anything is possible. On one hand, four studies conducted by Orexigen demonstrated that overweight patients lost, on average, 4.2 percent more weight than patients taking a placebo. On the other hand, this falls short of the FDA guideline that there should be at least a 5 percent difference in weight loss between these groups.

Contrave did meet a second effectiveness measure - at least 35 percent of patients, twice the proportion of those on the placebo, lost at least 5 percent of their weight. The FDA guidelines say a diet drug can be considered effective if it meets this requirement. However, “it is difficult to draw accurate conclusions about the long-term efficacy” of the proposed maintenance dose of Contrave, wrote Eric Colman, deputy director of the FDA’s Division of Metabolism and Endocrinology Products, in the briefing documents (pdf).

Yet the pill was also linked to more cases of high blood pressure, psychiatric side effects, dizziness and kidney dysfunction, raising speculation that additional trial work may be needed. For instance, the FDA staff, in its briefing, asks whether additional analysis should be done before or after approval and, specifically, a cardiovascular outcomes study is needed prior to approval. The med, by the way, combines the Wellbutrin antidepressant and a sustained release form of naltrexone, an opioid blocker used to treat addictions to alcohol and painkillers.

“Overall, the tone of the documents looks non-committal to us and did not contain any material surprises that can sometimes arise after FDA review,” Leerink Swann analyst Josh Schimmer wrote in a research note. “We are encouraged by the fact that we do not see anything materially new and the tone is not overtly negative by our read.”

As we have seen in recent months, safety remains paramount, especially when its comes to diet drugs that may raise safety signals, given the extensive use that experts anticipate among consumers. Remember that the FDA recently forced Abbott Laboratories (NYSE:ABT) to withdraw its Meridia pill. Even though the agency has not approved a new diet drug since Roche’s Xenical in 1999, there is no reason to believe the dearth of such pills is a reason to give readily Contrave a green light. The scales, if you will, are tipping in favor of continued caution.

Disclosure: None