Sprout Pharmaceuticals resubmits flibanserin NDA for treating HSDD in pre-menopausal women

Sprout Pharmaceuticals, the Raleigh-based pharmaceutical company developing flibanserin, a treatment being evaluated for Hypoactive Sexual Desire Disorder (HSDD) in pre-menopausal women, confirmed today that the company has resubmitted the New Drug Application (NDA) for flibanserin earlier this year and expects US Food and Drug Agency (FDA) action before the end of 2013. If approved, flibanserin would be the first FDA approved treatment for HSDD in pre-menopausal women.

HSDD, a form of female sexual dysfunction, is defined as a persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity that causes marked distress or interpersonal difficulty. The 2012 Prescription Drug User Fee Act (PDUFA) V identified addressing female sexual dysfunction as one of 20 priority areas in the FDA's Patient-Focused Drug Development Program.

Sprout's announcement comes in connection with the recent publication of positive results of a Phase 3 clinical trial involving more than 1,000 patients in the Journal of Sexual Medicine. Study 511.147 was a key component of the company's resubmission in response to the FDA's 2010 Complete Response Letter to the original flibanserin NDA.

Study authors (Molly Katz, MD; Leonard R. DeRogatis, PhD, et al) concluded that flibanserin resulted in statistically significant improvements in the number of satisfying sexual events (SSEs), as well as increase in sexual desire when compared with placebo. Flibanserin was further associated with significant reductions in distress associated with low desire, a hallmark characteristic of HSDD.

Study 511.147 was a randomized, placebo-controlled trial in which nearly 1,100 pre-menopausal women with HSDD (mean age: 36.6 years) were treated with flibanserin 100 mg once daily at bedtime or placebo for 24 weeks. Co-primary end points were the change from baseline to study end in number of satisfying sexual events and increases in desire as measured by the Female Sexual Function Index (FSFI) desire domain score.  Secondary end points included the change from baseline in FSFI total score, Female Sexual Distress Scale-Revised (FSDS-R) total score, and the FSDS-R Item 13 score, which measures distress associated with low desire on FSDS. Further, clinical meaningfulness of outcomes was assessed using the FDA recommended Patient Global Index of Improvement (PGI-I).  All endpoints achieved statistical significance.

The study's authors found the drug to be well tolerated during patients' 24 weeks of use. The most frequently reported adverse events in the flibanserin group were somnolence, dizziness, and nausea, with adverse events leading to discontinuation in 9.6% of women receiving flibanserin vs. 3.7% on placebo.

"In cases where there is a bio-chemical component to sexual dysfunction, women, unlike men, have no biopharmaceutical options," commented Dr. Sheryl Kingsberg, Chief of Behavioral Medicine at University Hospitals Case Medical Center and Professor in Reproductive Biology and Psychiatry at Case Western Reserve University School of Medicine. "The consistency of flibanserin's statistically significant effect on satisfying sexual events and desire, while decreasing the distress of women experiencing HSDD, is very encouraging."

"This additional data, which is a key part of Sprout's resubmission of the flibanserin NDA, is responsive to feedback received from FDA previously," said Cindy Whitehead, chief operating officer of Sprout. "With this study, and other information included in our resubmission, Sprout believes that it has addressed the concerns raised by the FDA during its previous review. We look forward to working with the Agency during the ongoing review process."