Bremelanotide Treatment Improves Sexual Function and Reduces Associated Distress Levels in Women

A recent randomized, double-blind, placebo-controlled phase IIb trial of bremelanotide for the treatment of female sexual dysfunction actually required two stages of analysis, both of which were presented in New York City on May 6, 2014, at the American Psychiatric Association’s 167th annual meeting.

Bremelanotide is a melanocortin-receptor-4 agonist that targets a receptor system in the central nervous system that is active in such areas as hair and skin pigmentation, sleep, and weight, as well as sexual arousal.

The first stage of research, explained Leonard R. DeRogatis, PhD, director of the Maryland Center for Sexual Health, was designing a more thorough questionnaire that would measure not just women’s sexual dysfunction, but also their distress at that lack of function. As he pointed out, “You can have all the symptoms of sexual dysfunction in the world, but if you have no desire, you can’t be given a diagnosis of distress.” Or, in lay terms, “Some menopausal women say, ‘Thank God that’s over.’”

Accordingly, his team of researchers added two items to the 13 existing questions on the FSDS-R, thus creating what he called the Female Sexual Distress Scale-Desire/Arousal/Orgasm.

The two new items ask women: “How often did you feel concerned by difficulties with sexual arousal?” and “How often did you feel frustrated by problems with orgasm?” over the past 30 days. There were a number of subtopics, such as “How often did you feel embarrassed about your sexual problems?” and “How often did you feel bothered by low sexual desire?”

Armed with the enhanced questionnaire, the study then enrolled approximately 725 premenopausal women in the 12-week study. Each of the participants was in a stable, monogamous relationship that had been ongoing for at least six months, and many of them were in long-term marriages, according to Anita H. Clayton, PhD, a professor of psychiatry and neurobehavioral sciences at the University of Virginia in Charlottesville. She said she did not know if any were lesbian relationships, but she said the results theoretically should be the same for both heterosexual and same-sex partnerships.

The participants had all been diagnosed with hypoactive sexual desire disorder, female sexual arousal disorder, or both conditions, for at least six months.

The study medication was self-administered at a dosage of 0.75 mg, 1.25 mg, or 1.75 mg, by subcutaneous injection usually in the abdominal area. According to Clayton, bremelanotide is effective for 24 hours, and it can be safely used as many as 16 times in a month.

In its most important results, using the new questionnaire, the trial found significant improvements at the highest dosage of bremelanotide in terms of frequency of desire, frequency of arousal, ease of arousal, continuation of arousal, and orgasm, compared with the cohort on placebo. For instance, the mean change in orgasms was a reported increase of 1 for the 1.75 mg dosage versus just 0.4 for the group on placebo. Frequency of desire was nearly double: a mean of 0.9 for the group on 1.75 mg of bremelanotide and 0.5 for the control group.

If they get approval from the Food and Drug Administration, the researchers hope to start phase III trials by the end of the year.