Britons are first to test male contraceptive pill

A British group has become the first in the world to test a male contraceptive pill.

Female oral contraceptive pills have been around since the 1960s.

A British group has become the first in the world to test a male contraceptive pill that scientists believe could transform how responsibility for birth control is shared between the sexes.

The drug, called YCT-529, is being given to 16 volunteers at a clinic in Nottingham, England, more than 60 years after the female pill was introduced in the UK.

The male version shuts off a protein called retinoic acid receptor alpha (RAR-alpha) in the body. The protein is prevented from binding to a form of vitamin A, which should stop sperm being formed in the testes.

The approach, which has worked well in the laboratory on mice and monkeys, differs from earlier attempts at a male contraceptive, which typically sought to reduce sperm production by suppressing the hormone testosterone.

A YouGov poll in 2019 found about 33 per cent of sexually active British men would consider taking a male version of the pill – the same figure as the percentage of women who use hormonal contraception.

Finding a drug that can safely and temporarily block male fertility has proven a challenge, in part because men produce about 1000 sperm per heartbeat, compared with women who produce one or two eggs a month.

Among mice, YCT-529 was 99 per cent effective in preventing pregnancies. In monkeys, it decreased sperm counts after two weeks. In all the tests on animals, the effects were reversed when the treatment was ended.

The trials in Nottingham will at first involve volunteers who have decided not to have children and have had vasectomies being given low doses to assess safety.

Results are expected in the northern spring. If they are positive, larger – and far more expensive – trials will be required to test its effectiveness and side-effects.

Professor Gunda Georg, of Minnesota University, who has led the drug’s development in a scheme funded by the US government, said the test “could be historic”. She added: “We know many men would be interested in a male contraceptive pill. And whenever I describe this work to women they always say: ‘It’s about time’.”

At present men have two approved contraceptive options – vasectomies, which are 99 per cent effective but are relatively difficult to reverse, and condoms, which guard against sexually transmitted diseases but are less effective at preventing pregnancies.

The trial is being run by YourChoice Therapeutics, a company based in San Francisco that has been funded by Y-Combinator, a start-up accelerator.

Akash Bakshi, chief executive of YourChoice, said the pill could be taken with home test kits that would allow men to check that their sperm levels were too low to cause a pregnancy.

The latest effort appears to be the first male contraceptive test to begin in several years. Previous attempts to suppress testosterone were linked to an increased risk of cardiovascular disease, weight gain, acne and mood changes, including increased aggression and decreased libido. Those side-effects were deemed too severe, though it is often noted that women who take birth control pills can face similar ones.

Mr Bakshi said: “YCT-529 blocks a protein – not hormones – to prevent sperm production. We believe this will be more attractive to men, most of whom view pregnancy prevention as a shared responsibility.”

Professor Richard Anderson, of Edinburgh University, who is not involved in the study, said there was “good reason” to think the pill would work. “But of course it may not,” he added. “Or there may be unexpected off-target effects. Surveys and the willingness of men to take part in trials confirms there is a demand.”

Professor Georg blamed “a lack of interest from the pharmaceutical industry” for the failure to produce a male pill.

“Contraception is a risky situation,” she said. “We’re treating young, fertile males. So the requirements to bring something to market are very high – it has to be safe, it has to be reversible, it cannot affect any offspring born after the contraception is ended. These issues make the industry shy away.”

Heather Vahdat, executive director of the Male Contraceptive Initiative, which has invested in the pill, said “significant” work lay ahead. “We believe YCT-529’s first human study is a significant step toward a future where both men and women have the power to decide and control contraceptive use, pregnancy and child bearing,” she said. “A kind of health equity we believe is long overdue.”

Other potential male contraceptives being tested include a hormone gel called NES/T, which men would apply daily to their shoulders and upper arms. Researchers in India are testing a nonsurgical vasectomy procedure, known as reversible inhibition of sperm under guidance, which involves injecting a gel into the tubes in the scrotum.

The Times