PT-141 (Bremelanotide)

The RECONNECT program consisted of two identical, randomized, double-blind, placebo-controlled Phase 3 trials (Study 301 and Study 302) enrolling 1,247 premenopausal women with a clinical diagnosis of hypoactive sexual desire disorder. Participants self-administered 1.75 mg of bremelanotide or matched placebo subcutaneously, on demand, over a 24-week core period. The co-primary endpoints were change from baseline in the Female Sexual Function Index desire domain score (FSFI-D) and change in the Female Sexual Distress Scale–Desire/Arousal/Orgasm Item 13 score (FSDS-DAO Item 13). Both endpoints reached statistical significance in favor of bremelanotide versus placebo across both studies (integrated analysis P < 0.001 for each). The most frequent adverse events reported in the active arm were nausea, flushing, and headache, consistent with the known pharmacology of melanocortin receptor activation.

Researchers ran two large, identical clinical trials of bremelanotide in premenopausal women with low sexual desire. About 1,247 women were randomly assigned to inject either bremelanotide or a placebo when they wanted to, for 24 weeks. The women using bremelanotide reported statistically significant increases in sexual desire and significant reductions in the distress they felt about low desire, compared to placebo. The most common side effects were nausea, flushing of the skin, and headache — all consistent with how melanocortin receptors work throughout the body.

This early-phase, randomized, double-blind, placebo-controlled crossover study examined the pharmacology and subjective response profile of intranasal bremelanotide in premenopausal women with female sexual arousal disorder. The authors characterize bremelanotide as a cyclic heptapeptide analog of α-MSH acting centrally via the melanocortin receptor system, with activity at MC3R and MC4R subtypes expressed in hypothalamic and limbic regions implicated in sexual motivation. Pharmacokinetic measurements supported a relatively short systemic half-life consistent with on-demand dosing protocols. The study laid the mechanistic foundation for later Phase 3 work, distinguishing PT-141's central, receptor-mediated mechanism from peripheral vasoactive agents.

Scientists studied how PT-141 works in the brain and how women responded to it during an early controlled study. PT-141 is a small, ring-shaped peptide that mimics a natural body hormone called α-MSH. Instead of acting on blood vessels like some other compounds, it activates receptors in brain regions that control sexual motivation. This study established the mechanism that later, larger trials would build on — showing that PT-141 acts on the central nervous system rather than on the body's plumbing.