Safety of Contrave (Naltrexone-Bupropion)

The safety of Contrave is the subject of a fairly glowing review just published in Expert Opinion on Drug Safety. This attention comes as the anticipated FDA approval for Contrave draws near. FDA is due to act on Orexigen’s application for approval in the U.S. by June 10.

Contrave is a combination of two marketed drugs: the antidepressant buproprion and natrexone, an opoid receptor blocker used to treat drug dependence. In a patented formulation developed by Orexigen and branded as Contrave, this combination has been studied in more than 13,000 patients for treating obesity.

In this new review, Jessica Verpeut and Nicholas Bello conclude that naltrexone-bupropion offers less severe adverse effects than the phentermine-topiramate (Qsymia) and better efficacy than orlistat (Alli or Xenical) and lorcaserin (Belviq). They also noted that it lacked the abuse potential of phentermine or lorcaserin. The only deficit they noted was less weight loss than phentermine-topiramate.

This glowing assessment leaves us with a question. Will Contrave meet with more success than the slow going that Qsymia and Belviq have seen?

Certainly, a safety advantage could help. Primary care physicians have proven themselves reluctant to prescribe medications for obesity treatment. But, frankly, beyond offering brilliant, terse advice along the lines of “you ought to lose some weight,” all too many primary care physicians do very little to treat obesity.

We have a growing cadre of obesity medicine physicians, with more becoming certified every year by the American Board of Obesity Medicine. Still, the numbers are small.

Some drug industry analysts see an opening for Contrave. One such analyst, Charles Duncan of Piper Jaffrey, recently said:

We think that, in the short term, Contrave may not have better uptake than the other two drugs. But in the longer term, looking out a couple of years, I think Contrave will be the winner. The other thing that differentiates the Orexigen story from the two comparables is that the company has the potential to get approval for and launch Contrave in Europe. Neither of the other two products is positioned for that, because neither has completed a cardiovascular outcomes study.

Treatment of obesity is an area of tremendous unmet medical needs. Progress is slow, but steady. Opportunists will likely get impatient, but more dedicated people and organizations will persist until the needs are met.

Click here for the publication by Verpeut and Bello. Click here for more analysis on the prospects for Contrave.

Safety, photograph © Jonathan Warner / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.