FDA Approves Bupropion/Naltrexone (Contrave) for Obesity

September 10, 2014

The US Food and Drug Administration (FDA) has approved the combination of bupropion/naltrexone, developed by Orexigen Therapeutics, to be known as Contrave, for the treatment of obesity.

The FDA first rejected the drug combination in February 2011, asking the company to conduct a cardiovascular-outcomes trial because of concerns about the cardiovascular safety profile of bupropion/naltrexone when used long term in a population of overweight and obese subjects.

Orexigen Therapeutics subsequently began the 8900-patient Light Study and, following encouraging interim safety and outcomes data from this trial, the company resubmitted the US new drug application at the end of last year.

In June of this year, the company announced the FDA was extending, by 3 months, its review of bupropion/naltrexone.

Now the agency appears at least partially satisfied. However, the approval comes with a requirement for several postmarketing studies, including one further evaluating the cardiovascular risks of the drug.

In addition, the drug comes with a boxed warning to alert health professionals and consumers about the risk for suicidal thoughts associated with bupropion and serious neuropsychiatric events associated with bupropion's use in tobacco-cessation therapy.

The agency cleared the drug for use in adults with a body mass index (BMI) of 30 or higher and adults with a BMI of 27 or higher with one or more weight-related conditions, including hypertension, type 2 diabetes, or high cholesterol.

Four Obesity Drugs on Market Now in US

The approval of bupropion/naltrexone brings to 4 the number of obesity drugs now available in the United States. In addition, the approval comes on the day before an FDA advisory committee is to discuss whether to recommend approval of another potential obesity treatment, the glucagonlike peptide-1 (GLP-1) agonist liraglutide (Victoza, Novo Nordisk), which is already approved for the treatment of type 2 diabetes.

The currently available drugs include the nonprescription agent orlistat (Alli, GlaxoSmithKline) as well as 2 recently approved prescription agents, lorcaserin (Belviq, Eisai) and phentermine/topiramate (Qsymia, Vivus). The latter have provoked controversy, however, with 2 doctors writing an opinion piece earlier this year in JAMA Internal Medicine calling them "slim pickings" for the treatment of obesity.

But representatives from 2 obesity organizations responded in letters to the same journal this summer, accusing the doctors of having trivialized obesity and also refuting many of their statements.

Among the criticisms of these doctors was the fact that the European Medicines Agency has rejected lorcaserin and phentermine/topiramate, citing numerous safety concerns, despite them both being approved in the US.

Bupropion/naltrexone is also awaiting approval for obesity in Europe, and it remains to be seen how the EU agency will rule on this agent.

European doctors, for their part, have lamented the fact that they have little in the pharmaceutical armamentarium with which to treat obesity. The only available option for pharmaceutical treatment of obesity in Europe is orlistat, which is available without a prescription in a low dose (Alli, GlaxoSmithKline) or by prescription at a higher dose (Xenical, Genentech).


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