Vivus obesity drug delayed

The US Food and Drug Administration (FDA) has asked Vivus for more safety information regarding Qnexa (phentermine and topiramate), which the company is hoping to market as a treatment for obesity.

At an end-of-review meeting with the company, the FDA asked Vivus to look into whether it would be feasible to analyse existing data to determine the historical incidence of oral cleft in the children of women who have taken topiramate as a prophylaxis for migraine. The FDA has not requested that the company conduct additional clinical trials, Vivus noted.

The company said it believes the FDA's concerns are related to two published reports citing two oral clefts in the UK Epilepsy and Pregnancy Register and four, including two isolated cleft lips, from the North American AED Pregnancy Registry. The company stressed that in its own clinical trials of Qnexa, which included 15 births from women who took the drug, there were no reports of birth defects.

Vivus has not yet provided a planned timeline for the resubmission of the marketing application for Qnexa. The company said the timeline would be announced after it had reached an agreement with the FDA on the feasibility assessment.

The company eventually hopes to market Qnexa for weight loss, type 2 diabetes and obstructive sleep apnea. The once-a-day, controlled-release capsules are intended to decrease appetite and increase satiety. Phentermine, which was approved in 1959, is already cleared in the US as a short-term treatment for weight reduction. Topiramate was approved in 1996 as a treatment for epilepsy and was subsequently cleared as a prophylactic for migraine.

In a close vote at an advisory committee meeting in July, panel members recommended against approval of Qnexa as an obesity treatment, citing the increased risk of psychiatric and cognitive issues linked to the drug in the company's trials, as well as the potential risk of birth defects.