10 Years to a Male Contraceptive?

March 25, 2019

NEW ORLEANS — More early research into a possible male contraceptive pill has been presented here at ENDO 2019: The Endocrine Society Annual Meeting.

"Our results suggest that this pill, a modified testosterone which combines two hormonal activities in one, will decrease sperm production while preserving libido," said Christina Wang, MD, of the Clinical and Translational Science Institute at the Los Angeles Biomed Research Institute (LA BioMed), Torrance, California, who presented the findings of the small brief study here during a press conference. The results were also reported during a poster session at the meeting.

Last year, the same team, known collectively as the Male Contraceptive Clinical Trial Network Research group, presented encouraging findings from a preliminary study with another potential oral male contraceptive, an investigational oral synthetic androgen called dimethandrolone undecanoate (DMAU), which were published in the Journal of Clinical & Endocrinology Medicine. A 12-week study of this compound is ongoing, Wang told Medscape Medical News.

Both compounds are being pursued in parallel. "The goal is to find the compound that has the fewest side effects and is the most effective," she noted.

Men Want a Male Contraceptive, Team Working on a Number of Options

Current methods of contraception available to men are limited to condoms, withdrawal/rhythm method, or vasectomy, Wang explained.

As well as the two pills, the team is also looking at a contraceptive gel for men — it has just begun a large study of this product — and is investigating a longer-acting intramuscular injection, too.

"We are covering all ground. We want to offer as many different [contraceptive] methods to men as we can, similar to the choices available to women," Wang said.

"Safe, reversible hormonal male contraception should be available in about 10 years," she predicted.

Study coauthor Stephanie Page, MD, PhD, professor of medicine at the University of Washington, Seattle, told Medscape Medical News that 10 years is likely "being optimistic" but that the team is hoping that they can attract a pharmaceutical company to invest in the work, which will speed things up.

"We're hoping for industry funding or help from a nongovernmental organization (NGO), but the problem is that this field is unknown in terms of risk/benefit from a regulatory standpoint," she explained.

The researchers insist there is an appetite among men for male birth control. They cited a multinational survey of 9000 men published in Human Reproduction in 2005 that showed 55% of men in stable relationships would want to try a new hormonal male contraceptive method if it was reversible. The pill was the most preferred method, followed by a long-acting injection.

Page conceded to Medscape Medical News that this survey is "old" and only examined men in stable relationships. "Times change," she said, adding that it would be useful to perform another survey to gauge male interest in such a product.

Circulating Testosterone Dropped With 11-beta-MNTDC

In the new study reported here, 40 healthy men aged 18-50 years were recruited in Los Angeles and Washington state.

Thirty men received the 11-beta-MNTDC pill with food once a day and 10 men received placebo. Fourteen of the men taking active drug took 200 mg of 11-beta-MNTD, and the remaining 16 men took a dose of 400 mg.

The trial ran for 28 days and participants presented twice weekly for assessment of safety parameters. There were no clinically important adverse events or related discontinuations, Wang said.

Among the men receiving the 11-beta-MNTDC, the average circulating testosterone level dropped as low as is seen in androgen deficiency.

The compound "markedly and rapidly" suppressed luteinizing hormone and follicle stimulating hormone, which control the production of testosterone and sperm, Wang said, and few participants complained of any effect on sexual function "because 11-beta-MNTDC also has male hormonal activity," she noted.

Adverse effects reported in those taking 11-beta-MNTDC included four men with fatigue, six with headache, five with acne, five with decreased libido, and two with mild erectile dysfunction. The drug effects were reversible after stopping treatment, Wang noted.

The next step will be a longer study, lasting 3 months or longer, to demonstrate sperm suppression — because the cycle of spermatogenesis takes up to 90 days — and to further investigate safety, she explained.

If successful, 11-beta-MNTDC will be tested in larger studies and then in sexually active couples.

A placebo-controlled study of the intramuscular male contraceptive is also ongoing, Page told Medscape Medical News, which has so far enrolled 50 or 60 men at two US sites.

And a larger trial of the gel, which combines the progesterone nestorone with testosterone — known as NerTes gel — has recently begun, with the aim of recruiting 400 sexually active couples at nine sites around the world, as reported by Medscape Medical News.

For updates on the work of the Male Contraceptive Clinical Trial Network Research team, information can be found on the Center for Male Contraceptive Research & Development website, on Twitter (@MaleBirthCtrl), and Instagram (@malecontraception).

Wang has reported receiving research support from Clarus Therapeutics, Antare, and TesoRx.

ENDO 2019. Presented March 24, 2019. Abstract LB042.

Follow Lisa Nainggolan on Twitter: @lisanainggolan1. For more diabetes and endocrinology news, follow us on Twitter and on Facebook.

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