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Bremelanotide () INN, USAN), formerly known as PT-141, is a peptide drug which is (or has) been under development by Palatin Technologies as a treatment for female sexual dysfunction (FSD), hemorrhagic shock, and reperfusion injury. Bremelanotide was originally tested for intranasal administration in treating FSD but this application was temporarily discontinued in 2008 after concerns were raised over increased blood pressure seen with bremelanotide administration in some patients. As of December 2014, Palatin is conducting a human phase III study using a subcutaneous drug delivery system that appears to have little effect on blood pressure. ==Development== Bremelanotide was developed from the peptide hormone melanotan II which underwent testing as a sunless tanning agent. In initial testing, melanotan II did induce the production of darkening dermal pigmentation (melanogenesis) but additionally caused sexual arousal and spontaneous erections as unexpected side effects in nine out of the ten original male volunteer test subjects. In studies, bremelanotide was shown to induce lordosis in an animal model and was also effective in treating sexual dysfunction in both men (erectile dysfunction or impotence) and women (sexual arousal disorder). Unlike sildenafil (Viagra) and other related medications, it does not act upon the vascular system, but directly increases sexual desire via acting in the brain. A phase III clinical trial was scheduled to begin in the first half of 2007, but was delayed until August 2007. On August 30, Palatin announced that the U.S. Food and Drug Administration had expressed serious concerns regarding the risk/benefit ratio of bremelanotide with regards to the side effect of increased blood pressure. The FDA stated that it would consider alternate uses for bremelanotide, including as a treatment for individuals who do not respond to more established ED treatments. However, on May 13, 2008, Palatin Technologies announced it had "discontinued development of bremelanotide for the treatment of male and female sexual dysfunction" while concurrently announcing plans to develop it as a treatment for hemorrhagic shock instead. The company additionally announced intentions to focus its attention on another, more selective compound, PL-6983, that was found to produce lower increases in blood pressure in animal models. Palatin has since re-initiated bremelanotide studies for ED and FSD using a subcutaneous delivery method. On August 12, 2009, the company announced that in a double-blind study of 54 volunteers bremelanotide failed to evoke the hypertensive side effects seen with the nasal delivery system used in prior studies, concluding that "variability of uptake" inherent in intranasal administration of the drug resulted in "increases in blood pressure and gastrointestinal events...primarily related to high plasma levels in () a subset of patients" and that subcutaneous administration of the drug circumvented the potential for this side effect. Palatin has completed a human phase IIb study utilizing subcutaneous administration and reported positive results.〔http://www.palatin.com/news/news.asp?ud=306〕 Bremelanotide, via the subcutaneous injection route, has been studied in human clinical trials in doses of 0.75, 1.25, and 1.75 mg, with its effectiveness in treating sexual dysfunction increasing with each dosage and side effect rates remaining similar.〔http://www.palatin.com/pdfs/bremelanotide.pdf〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「bremelanotide」の詳細全文を読む スポンサード リンク
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