A male pill could be on the horizon after early trials showed a once-daily tablet was safe and appeared to work, according to researchers.
The quest to develop a male contraceptive pill has been long and fraught. Men who want a reversible form of contraception have said in surveys that they would prefer a pill to injections or gels, which are also being developed.
The new pill is known by the chemical name dimethandrolone undecanoate, or DMAU. Like most female contraceptive pills, it contains a combination of hormones – an androgen such as testosterone, and a progestin.
“DMAU is a major step forward in the development of a once-daily ‘male pill’,” said Stephanie Page, a professor of medicine at the University of Washington in Seattle, and the senior investigator on the study. The team have overcome previous problems that assailed developers of male hormonal pills, she believes.
One of those was the tendency of available forms of testosterone to cause liver inflammation. Also, because they clear the body relatively quickly, men would have had to take the pills twice a day.
The team, presenting their results at the Endocrine Society’s annual conference in Chicago, have added in the long-chain fatty acid undecanoate, which slows down the clearance of the hormone from the body, meaning one pill a day should be enough.
It is still early days, but the team believe the results from their safety trial in 100 men are promising. Of the 100 volunteers aged 18-50, 83 completed the month-long study, including giving blood samples for hormone and cholesterol testing at the beginning and end.
Different doses of the pill and different formulations were tested at university medical centres in Washington state and California. Each dose group included five men who were randomly assigned to receive an inactive placebo and another 12 to 15 men who were given the new pill.
Volunteers took the drug or placebo for 28 days once daily with food. DMAU must be taken with food to be effective, said Page.
At the highest dose tested, 400mg, there was “marked suppression” of the hormones required for sperm production, she said.
Low testosterone levels can lead to loss of sex drive and fatigue, but most of those on the trial did not appear to suffer. “Despite having low levels of circulating testosterone, very few subjects reported symptoms consistent with testosterone deficiency or excess,” Page said.
However, all the men taking the male pill had weight gain and a drop in their HDL or good cholesterol levels. But Page said this was mild and not a reason for concern, and that liver and kidney function was good.
“These promising results are unprecedented in the development of a prototype male pill,” Page said. “Longer-term studies are currently under way to confirm that DMAU taken every day blocks sperm production.”