PT-141

PT-141, a melanocortin receptor agonist, demonstrates concentration-dependent proerectile effects in rats and nonhuman primates through a CNS-mediated mechanism^[1]

This preclinical pharmacology study characterized the mechanism of PT-141 (bremelanotide) using MC receptor-selective agonists and antagonists in rat and nonhuman primate erectile function models. PT-141 at subcutaneous concentrations of 0.1-3 mg/kg produced concentration-dependent penile erection in male rats that was blocked by the MC3R/MC4R antagonist SHU-9119 but not by the alpha1-adrenergic antagonist prazosin, establishing centrally mediated rather than peripheral vascular action. The medial preoptic area (MPOA) was identified as the principal CNS locus using stereotaxic microinjection experiments. This mechanistic distinction from PDE5 inhibitors supported PT-141's characterization as acting on central desire pathways rather than peripheral vascular function.

Last verified: 2026-04-03

Phase 2 research study of bremelanotide (PT-141) for hypoactive sexual desire disorder in premenopausal women^[2]

This randomized, double-blind, placebo-controlled Phase 2 research study evaluated subcutaneous bremelanotide (1.25 mg and 1.75 mg) in premenopausal women with diagnosed hypoactive sexual desire disorder across 12 weeks of on-demand use. Coprimary endpoints of satisfying sexual events per month and Female Sexual Function Index desire domain scores were both significantly improved in the 1.75 mg arm versus placebo. The most common adverse events were transient nausea (27%) and flushing (20%), generally resolving within two hours. These results supported the subsequent Phase 3 program leading to FDA approval of bremelanotide (Vyleesi) in 2019.

Last verified: 2026-04-03