What Is PT-141 Peptide?
PT-141, also known as bremelanotide, is occasionally called the female Viagra. It was previously investigated in phase IIb human clinical trials to treat female hypoactive sexual desire disorder (HSDD). It is derived from another synthetic melanocortin known as melanotan 2 (MT-2). PT-141 is a melanocortin that interacts with melanocortin 4 receptor (MC-4R) and MC-1R. In 2009, PT-141 was studied for treating acute hemorrhage.
Molecular Formula: C50H68N14O10
Molecular Weight: 1025.2 g/mol
PubChem: CID 9941379
CAS Number: 189691-06-3
Research related to PT-141 (bremelanotide)
PT-141 Peptide and Sexual Arousal
PT-141 uniquely stimulates MC-4R, which triggers sexual arousal in the central nervous system and affects sexual behavior. Studies in mice agonist binding to MC-4R bring sexual arousal and enhanced copulation in both males and females. The mechanism of PT-141 beings different from Viagra; it helps to treat both male and female sexual arousal disorders that are not caused by reduced blood flow to the genitals.
One-third of men who suffered from erectile dysfunction (ED) but did not respond to sildenafil (Viagra) experienced satisfactory erection for sexual intercourse using PT-141 (administered via nasal spray). The strong dose-dependent response in the trial indicated the effectiveness of PT-141 in some cases. PT-41 thus can be helpful to treat ED when Viagra is non-responsive.
Interestingly, it was removed from clinical trials for treating women with HSDD despite showing increased female sexual satisfaction and reducing female sexual distress scores without side effects. Experts on female sexual dysfunction (FSD) consider a lack of established endpoints for trials of FSD and socio-cultural biases against women’s sexual health as the essential reasons for the non-approval of PT-41. Experts are hopeful for FDA to issue concrete guidelines for evaluating trials of such potential drugs. They also suggest the PT-41 treatment if combined with other existing modalities will enhance both physiological and psychological efficacies.
In 2017, partly due to the outcry against the cessation of earlier trials, Phase II Reconnect trials were initiated for subcutaneous injections of PT-141 for FSD. The newest variant of PT-141, called Rekynda, might soon be marketed for use in the United States. PT-141, at that point, could be used off-label for treating both male and female sexual dysfunction. The new trials abided by the modified endpoint for effective clinical trial evaluation of such drugs in the treatment of FSD.
The MC-1R has shown to mediate important anti-fungal and anti-inflammatory effects in a rat model of specific fungal infection. This will be relevant as current drugs have limited mechanisms of action and show adverse effects in some patients. The alternative therapy can control morbidity and mortality, especially in immunocompromised patients.
PT-141 and Hemorrhage
In 2009, modified PT-141 was investigated for use in hemorrhagic shock. The peptide controls ischemia and protects tissues against inadequate blood supply hypovolemic (hemorrhagic) shock through interaction with both MC-1R and MC-4R. It was further observed in phase IIb trials that the intravenous dose of the drug shows no side effects. The modified version is referred to as PL-6983.
The MC-1R receptor being an important stimulus of DNA repair pathways, is of relevance in cancer treatment and prevention. People with variants of MC-1R are more prone to both basal cell and squamous cell carcinoma. Altered PT-141 can be used to bind to these variants and prevent or treat these cancers.
Right now, PT-141 is well known for the treatment of sexual dysfunction. There is potential to expand its use for other diseases. For instance, a mutant or deleted MC-4R triggers some instances of obesity and influence about 6% of early-onset obesity cases. PT-141 helps to study this specific reason for obesity and illustrates a pathway for intervention. MC-1R is involved in pain, inflammation, kidney pathology, and the spread of infection; the peptide helps investigate diverse research domains.
PT-141 exhibits minimal side effects, low oral bioavailability, and excellent subcutaneous bioavailability in mice. The dosage (per kg) in mice does not match humans.