FDA sheds light on flibanserin approval

The Food and Drug Administration is providing a rare look into the agency’s decision-making process surrounding the approval of flibanserin (Addyi) for female hypoactive sexual desire disorder (HSDD) earlier this year.

Officials in the FDA’s Division of Bone, Reproductive, and Urologic Products shared their perspective on the factors behind the drug’s approval in a commentary published online in the New England Journal of Medicine on Dec. 9 (doi: 10.1056/NEJMp1513686). “In the face of divergent views, we at the FDA think it’s important to clarify why flibanserin was approved after being rejected twice,” Dr. Hylton Joffe, the division’s director, and his colleagues wrote.

^{Courtesy of Sprout Pharmaceuticals}

Reviewing the data underpinning flibanserin’s three bids for approval, Dr. Joffe and his coauthors emphasized concerns that the initial data presented an unfavorable benefit-risk profile, given the drug’s known risks for hypotension and syncope, especially when taken in combination with alcohol or drugs that are moderate or strong cytochrome P-450 3A4 inhibitors.

Flibanserin won the day eventually because there had been convincing evidence presented regarding efficacy (though with modest effect size), there was no previous pharmacologic treatment for female HSDD, and phase III clinical trial data regarding flibanserin’s real-world use were reassuring, according to the FDA.

The agency’s review team required black box warnings regarding flibanserin’s risks, a Risk Evaluation and Mitigation Strategy (REMS), and ongoing post-marketing studies for safety.

Dr. Joffe and his colleagues acknowledged the divisive public discussions about flibanserin and in particular, the accusations of gender bias in the FDA’s scrutiny of the drug. Some of this criticism, Dr. Joffe and his coauthors wrote, was leveled by Even the Score, “an advocacy campaign partly funded by Sprout Pharmaceuticals, flibanserin’s sponsor after Boehringer Ingelheim sold the rights to the drug.”

Read the full Perspectives article in the New England Journal of Medicine.

koakes@frontlinemedcom.com

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