FDA declines to approve diet drug Contrave, says more study needed

WASHINGTON – The government on Tuesday unexpectedly rejected what appeared to be the most promising candidate among a class of new diet drugs, wiping out hopes for a new medication to fight obesity anytime soon.

Orexigen Therapeutics Inc. said the Food and Drug Administration is concerned about the heart side effects of its drug Contrave and will require a new study, a costly undertaking that may prove too burdensome for the small drugmaker.

The FDA’s ruling marks the third rejection of a weight loss drug in recent months, raising questions about whether any new drugs in the class can be made safe enough to win approval. The FDA has not approved a new diet pill in more than a decade.

The FDA request for an additional study suggests the agency may yet approve the drug, but makes that path much more difficult.

Analysts had viewed Contrave as the most promising of three new diet pills recently submitted to the agency. Contrave is a combination pill, mixing an antidepressant with an anti-addiction drug to curb appetite. Four out of 10 patients taking Contrave for a year lost at least 5 percent of their body weight. Those results narrowly met FDA’s guidelines for effectiveness.

Given the drug’s limited benefit, FDA’s rejection was not surprising, according to drug industry analyst Erik Gordon.

“You have life-threatening possible side effects in return for modest weight loss that might not be produced in the real world – no wonder the FDA wants more data,” said Gordon, a professor and analyst at the University of Michigan.