The Food and Drug Administration (FDA) has approved Addyi (flibanserin) for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD) as characterized by low sexual desire that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, problems within the relationship, or the effects of a medication or other drug substance. Prior to the approval of Addyi, there were no FDA-approved treatments for sexual desire disorders in men or women. Addyi is not indicated for the treatment of HSDD in postmenopausal women or men or for enhancing sexual performance.
Flibanserin is a once-daily, non-hormonal drug that is the first and only post-synaptic 5HT1A receptor agonist and 5HT2A receptor antagonist available for the treatment of premenopausal women with HSDD. Flibanserin may work by restoring prefrontal cortex control over the brain’s motivation/rewards structures enabling sexual desire to manifest. Specifically, flibanserin increases dopamine and norepinephrine while transiently decreasing serotonin in the brain’s prefrontal cortex, which may be accomplished by reduced glutamate transmission.
The FDA approval was based on Phase 3, randomized, double-blind, placebo-controlled, parallel-group North American studies of premenopausal women with a mean age of 36 years. In these trials, women counted the number of satisfying sexual events, reported sexual desire over the preceding four weeks (scored on a range of 1.2 to 6.0) and reported distress related to low sexual desire (on a range of 0 to 4). On average, treatment with Addyi increased the number of satisfying sexual events by 0.5 to one additional event per month over placebo increased the sexual desire score by 0.3 to 0.4 over placebo, and decreased the distress score related to sexual desire by 0.3 to 0.4 over placebo. Across the three trials, about 10% more Addyi-treated patients than placebo-treated patients reported meaningful improvements in satisfying sexual events, sexual desire or distress. The 100mg bedtime dose of Addyi has been administered to about 3,000 generally healthy premenopausal women with acquired, generalized HSDD in clinical trials, of whom about 1,700 received treatment for at least six months and 850 received treatment for at least one year.