PT-141 10 mg

PT-141 10 mg research-grade lyophilized peptide powder in a glass vial. Also known as bremelanotide, this cyclic heptapeptide analog of alpha-Melanocyte-Stimulating Hormone (α-MSH) is studied in melanocortin receptor signaling, sexual function models, appetite regulation and circulatory response research.

Research Overview

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide derived from Melanotan 2 and acting as a melanocortin receptor agonist. In experimental systems it is used to explore central MC4R/MC1R signaling, sexual function models, appetite control and vascular or circulatory responses under different stressors.

Primary Research Areas

• Melanocortin receptor signaling: MC4R/MC1R agonist used in studies of hypothalamic and CNS melanocortin pathways [6,7].
• Sexual function & arousal models: experimental paradigms assessing centrally mediated sexual behaviour and neuroendocrine responses [1,6,8].
• Appetite & energy-balance research: models investigating feeding behaviour, caloric intake and weight-regulation pathways via melanocortin signaling.
• Inflammatory & circulatory responses: studies exploring vascular tone, blood-flow changes and inflammatory markers in response to MC receptor activation [4].
• Nausea, flushing and headache: in the pooled phase 3 studies of 1,247 women, nausea hit 40% against 1.3% on placebo, flushing 20.3% against 1.3%, headache 11.3% against 1.9% and injection-site reactions 5.4% against 0.5%. Nausea was the commonest reason for stopping, and of the 684 women who went on to the 52-week open-label phase only 272 finished it [2,3].
• Blood pressure up, pulse down: in 397 premenopausal women, single doses raised systolic pressure by about 2.4 to 3.2 mmHg above placebo in the first four hours, with peaks usually lasting under 15 minutes. Heart rate fell by roughly 4.6 to 4.7 beats a minute at 1.75 mg. Twenty-six women came off the study for pre-set blood-pressure rises [3,4].
• Skin darkening with repeated doses: patches of darker skin were rare when the drug was used as labelled, but appeared in more than a third of subjects given up to 16 doses on consecutive days. How often a dose is taken is what decides it, not the size of any single dose [3].
• Lowers two other medicines: most drug interactions tested were not clinically important, but bremelanotide lowered the plasma concentrations of indomethacin and of naltrexone. For someone taking naltrexone by mouth for alcohol or opioid dependence a lower level can mean less protection. It comes from clinical pharmacology studies, not from a trial in patients [3].
• Taken together with alcohol: 24 healthy men and women took a 20 mg intranasal dose with or without 0.6 g/kg alcohol, enough to push peak blood alcohol above 80 mg/dL; there were no drug-related drops in blood pressure and no orthostatic drops. It is one small single-day crossover study and says nothing about repeated use alongside alcohol [5].

References

1. Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol. 2019;134(5):899-908. PMID 31599840. doi:10.1097/AOG.0000000000003500
2. Simon JA, Kingsberg SA, Portman D, et al. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstet Gynecol. 2019;134(5):909-917. PMID 31599847. doi:10.1097/AOG.0000000000003514
3. Clayton AH, Kingsberg SA, Portman D, et al. Safety Profile of Bremelanotide Across the Clinical Development Program. J Womens Health (Larchmt). 2022;31(2):171-182. PMID 35147466. doi:10.1089/jwh.2021.0191
4. White WB, Myers MG, Jordan R, et al. Usefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotide. J Hypertens. 2017;35(4):761-768. PMID 27977473. doi:10.1097/HJH.0000000000001221
5. Clayton AH, Lucas J, DeRogatis LR, et al. Phase I Randomized Placebo-controlled, Double-blind Study of the Safety and Tolerability of Bremelanotide Coadministered With Ethanol in Healthy Male and Female Participants. Clin Ther. 2017;39(3):514-526.e14. PMID 28189361. doi:10.1016/j.clinthera.2017.01.018
6. Pfaus J, Giuliano F, Gelez H. Bremelanotide: an overview of preclinical CNS effects on female sexual function. J Sex Med. 2007;4 Suppl 4:269-79. PMID 17958619. doi:10.1111/j.1743-6109.2007.00610.x
7. Pfaus JG, Sadiq A, Spana C, et al. The neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women. CNS Spectr. 2022;27(3):281-289. PMID 33455598. doi:10.1017/S109285292100002X
8. Althof S, Derogatis LR, Greenberg S, et al. Responder Analyses from a Phase 2b Dose-Ranging Study of Bremelanotide. J Sex Med. 2019;16(8):1226-1235. PMID 31277966. doi:10.1016/j.jsxm.2019.05.012