The decades-long ambition of creating a male contraceptive pill has today moved another step closer to reality.
For experts claim to have developed a tablet that’s 99 per cent effective at blocking pregnancies, putting it on par with the actual female version.
Tests on mice showed the non-hormonal drug, labelled YCT529, did not trigger any visible side effects.
And the rodents were able to father pups again four to six weeks after they stopped taking the contraceptive, according to the team.
University of Minnesota researchers plan human trials of the drug — which inhibits a protein to stop the formation of sperm — later this year.
Other candidates exist, including ones that have been trialled on men in Britain over the past few years.
But Professor Gunda Georg, who led the study, said YCT529 is ‘the furthest ahead of all contraceptive agents for men’.
The non-hormonal drug, which was given to mice orally for four weeks, works by inhibiting a protein important for the normal development of sperm. University of Minnesota experts, who designed the drug called YCT529, said it was 99 per cent effective at preventing pregnancy — on par with the female contraceptive pill. Pictured: stock of oral contraceptive pills
Scientists have been trying since the 1950s to develop an effective male oral contraceptive, including pills, gels and injections.
None have been approved, and even the most promising options are still thought to be years away from being widely available.
A major hurdle is that the female contraceptive works by preventing ovulation, which happens once a month.
Any male contraceptives would need to interrupt the production of millions of sperm made by men every day.
WHAT ARE THE CURRENT METHODS OF CONTRACEPTION AVAILABLE TO MEN?
There have been few changes in male contraception compared with the range of options available to women.
Although there’s ongoing research into a male contraceptive pill, there is not one available yet.
At the moment, the 2 contraceptive methods available to men are:
- condoms – a barrier form of contraception that stops sperm from reaching and fertilising an egg
- vasectomy – a minor, usually permanent, surgical procedure that stops sperm from reaching the semen ejaculated from the penis
The withdrawal method of taking your penis out of your partner’s vagina before ejaculating is not a method of contraception.
This is because sperm can be released before ejaculation and cause pregnancy.
Most of the drugs undergoing clinical trials target testosterone, blocking the male sex hormone from producing healthy sperm cells.
Doctors say, however, that the testosterone-blocking action can trigger weight gain, depression and increase cholesterol.
For comparison, the female combined contraceptive pill — which contains synthetic versions of female hormones oestrogen and progesterone — has been linked with similar mental health side effects.
The NHS says it can raise blood pressure and slightly increase the risk of blood clots and breast cancer.
Abdullah Al Noman, who helped create YCT529, said: ‘We wanted to develop a non-hormonal male contraceptive to avoid these side effects.’
YCT529 targets retinoic acid receptor alpha (RAR-a), a protein heavily involved in the development of cells, including sperm formation.
When they gave the drug orally to mice for four weeks, it ‘dramatically reduced’ their sperm counts, the researchers said.
It was also 99 per cent effective in preventing pregnancy and worked ‘without any observable side effects’.
‘The mice could father pups again four to six weeks after they stopped receiving the compound,’ the scientists said.
Condoms, which are ‘prone to failure’, and a vasectomy — a surgical procedure that permanently prevents pregnancy — are the only effective birth control options for men.
Men need ‘an effective, long-lasting but reversible contraceptive, similar to the birth control pill for women’, they said.
YCT529 will be tested in human clinical trials in the second half of 2022.
Professor Georg, head of medicinal chemistry at the university, said: ‘Because it can be difficult to predict if a compound that looks good in animal studies will also pan out in human trials, we’re currently exploring other compounds, as well.’
She told US news website The Daily Beast: ‘YCT529 is the furthest ahead of all contraceptive agents for men.’
Mr Al Noman told the website: ‘Birth control is a critical health-care issue. About more than half of all pregnancies in the US are unintended pregnancies.
‘And that can lead to very poor outcomes, whether in terms of the child’s health or maternal health and also financial and career advancement of women.
‘We need to have more investment in the research and development of the male birth control pill.’