Male contraceptive pill deemed 'safe' after trial breakthrough

The capsule limits the activity of sperm with few side effects

Scientists have brought the development of a “male contraceptive pill” one step closer to reality with the trial of a capsule which limits the activity of sperm with few side effects.

In a month-long study of 40 men, conducted by the University of Washington, researchers looked into the effectiveness of a once-daily capsule that aims to suppress levels of hormones which drive the production of sperm and testosterone in the testes.

The doctors found that levels of the hormones fell in men who took the daily capsules, suggesting that their sperm counts had been noticeably reduced.

As the study’s primary goal was to assess safety, researchers now say the next step will be to perform a longer trial which will help confirm the decline and determine if it is sufficient.

The team suggest that the drug would take at least 60 to 90 days to affect sperm production.

Stephanie Page, a professor of medicine and co-senior investigator on the trial at the University of Washington in Seattle, said: “The goal is to expand contraceptive options and create a menu of choices for men like we have for women.

“We are neglecting a major potential user population with the limited options currently available to men.”

The new study results were presented on 24 March at ENDO 19, the Endocrine Society's annual meeting in New Orleans.

Out of the 40 men involved, ten participants were given a placebo capsule – a pill that does not contain an active drug ingredient.

The other 30 men received 11-beta-MNTDC but in different doses. While 14 took a 200 mg dose, the remaining 16 took a 400mg dose.

Participants took the drug or placebo once daily with food for 28 days.

The study found drug side effects were mild and included fatigue, acne or headache in four to six men each.

Five men also reported a mildly decreased sex drive, while an additional two men described mild erectile dysfunction, however sexual activity was not decreased.

None of the participants stopped taking the drug because of the side effects, and all passed safety tests.

Christina Wang, a co-senior investigator on the trial at LA BioMed, said the next step in developing the male contraceptive pill is to measure the fall in sperm production directly.

“This study is very short and we need three months if not more to stop sperm production,” she said.

“All we have shown so far is that it shuts down the hormones that control the function of the testes.”

The researchers added that it could be a decade before a male pill is on the market. However, they believe there is still strong demand.

“Men have really limited options when it comes to reversible contraception,” Wang said.

“When we ask men about hormonal compounds, about 50 per cent are willing to try this new method. And when you ask their partners, the percentage is even higher.”

In 2016 a male contraceptive injection was found to be effective but with a high side effect rate which led to the trial being halted early.

Just under half the men involved in the study reported developing acne, a fifth reported mood disorders and around five per cent did not recover their sperm count one year after taking the drug.