Open-label extension study of flibanserin in women with hypoactive sexual desire disorder

Hypoactive Sexual Desire Disorder (HSDD) is a common form of Female Sexual Dysfunction characterized by low sexual desire that causes distress or interpersonal difficulty.

This 52-week open-label extension study aimed to assess the safety and tolerability of flibanserin, a postsynaptic 5-HT(1A) agonist/5-HT(2A) antagonist, in women with HSDD.

Women with HSDD who had completed a trial of flibanserin or flibanserin placebo received flexible-dose flibanserin (50 or 100 mg once daily at bedtime [qhs] or 25 or 50 mg twice daily [bid]) for 52 weeks.

Primary end points were: proportions of women with somnolence, sedation, fatigue, dizziness, nausea, and vomiting (adverse events [AEs] known to be associated with flibanserin); discontinuations due to AEs; and serious AEs. Secondary end points included change from baseline in Female Sexual Distress Scale-Revised total and Item 13 scores and Female Sexual Function Index (FSFI) total and desire domain score scores. FSFI total scores were used to classify women into FSFI remitters (FSFI score >26.55, indicating no clinical sexual dysfunction) and FSFI non-remitters (FSFI score <26.55).

Of the 1723 women who received flibanserin, 962 (55.8%) completed 12 months' treatment, and 883 women were exposed to flibanserin 100 mg qhs for ≥180 days. Somnolence, sedation, fatigue, dizziness, nausea, and vomiting were reported by 15.8, 1.6, 7.6, 6.9, 6.3, and 1.4% of participants, respectively. A total of 185 participants (10.7%) discontinued due to AEs. Serious AEs were reported by 1.2% of participants. At study end, 42% of baseline non-remitters had improved their FSFI score to remission level. The proportion of baseline FSFI remitters in remission rose from 83% at week 4 to a stable value of ∼90%.

Flibanserin was well tolerated. Sexual function improved in women who were not FSFI remitters at baseline, and was maintained in those who were remitters at baseline.