ORIGINAL RESEARCH—FSD PHARMACOTHERAPY Continued Efficacy and Safety of Flibanserin in Premenopausal Women with Hypoactive Sexual Desire Disorder (HSDD): Results from a Randomized Withdrawal Trial Evan R. Goldfischer, MD,* Jeffery Breaux, MD, † Molly Katz, MD, ‡ Joel Kaufman, MD, § William B. Smith, MD, ¶ Toshio Kimura, MPH,** Michael Sand, PhD,** and Rob Pyke, MD, PhD** *Hudson Valley Urology, Poughkeepsie, New York, NY, USA; † Women Center of Zachary, Baton Rouge, LA, USA; ‡ Katz and Kade, Inc., Cincinnati, OH, USA; § Urology Research Options, Aurora, CO, USA; ¶ Volunteer Research Group, University of Tennessee Medical Center, Knoxville, TN, USA; **Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA DOI: 10.1111/j.1743-6109.2011.02458.x ABSTRACT Introduction. Flibanserin is a 5-HT1A agonist/5-HT2A antagonist that has been shown to increase sexual desire and reduce distress in premenopausal women with Hypoactive Sexual Desire Disorder (HSDD). Aim. To assess the efficacy and safety of flibanserin over 24 weeks of double-blind treatment vs. placebo in premeno- pausal women with HSDD who showed a predefined response after 24 weeks of open-label treatment with flibanserin. Methods. Women (N = 738) were treated with open-label, flexible-dose flibanserin (50 mg or 100 mg/day) for 24 weeks. At week 24, women who showed a predefined response, measured using an eDiary, were randomized to 24 weeks of continued flibanserin therapy at optimized dosage (N = 163) or placebo (N = 170). The criteria for entering the double-blind phase were an increase from baseline to weeks 21–24 of 2 satisfying sexual events (SSE) and/or 4 “desire days.” A “desire day” was one in which a woman reported more than “no” desire. Main Outcome Measures. Coprimary endpoints were change from randomization to study end in SSE and desire score. Secondary measures included change in Female Sexual Function Index (FSFI) total and desire domain scores and Female Sexual Distress Scale-Revised (FSDS-R) total and Item 13 scores. Results. During the open-label period, mean SSE and desire score approximately doubled, and FSFI, FSDS-R total, and Item 13 scores improved. At the end of the double-blind period, flibanserin was superior to placebo in change from randomization in SSE, desire score, FSFI desire domain and total scores, and FSDS-R total and Item 13 scores (P < 0.05, for all). Flibanserin was well tolerated, and withdrawal reactions were not observed. Conclusions. At the end of the 24-week randomized withdrawal phase of a 48-week trial in premenopausal women with HSDD, flibanserin was superior to placebo on measures of SSE, sexual desire, overall sexual function, and sexual distress. Flibanserin was well tolerated, and no withdrawal reactions were observed following discontinuation. Goldfischer ER, Breaux J, Katz M, Kaufman J, Smith WB, Kimura T, Sand M, and Pyke R. Continued efficacy and safety of flibanserin in premenopausal women with Hypoactive Sexual Desire Disorder (HSDD): Results from a randomized withdrawal trial. J Sex Med 2011;8:3160–3172. Key Words. Flibanserin; Hypoactive Sexual Desire Disorder (HSDD); Premenopausal Women; Withdrawal; Safety; Low Sexual Desire Introduction H ypoactive Sexual Desire Disorder (HSDD) is defined in the American Psychiatric Associa- tion’s Diagnostic and Statistical Manual of Mental Disorders, 4 th Edition, Text Revision (DSM-IV- TR) as a persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity that causes marked distress or interpersonal difficulty [1]. The dysfunction should not be better 3160 J Sex Med 2011;8:3160–3172 © 2011 International Society for Sexual Medicine