Hormone-free male contraceptive pill being tested in the UK - how it works

A group of British men are the first in the world to test a new hormone-free male contraceptive pill.

Scientists hope that if the tests are successful, the daily pill could broaden shared responsibility for contraception between the sexes. Men can currently only use condoms or have a vasectomy while there are a vast array of contraceptives for women including the pill, the coil, a contraceptive injection and use of diaphragms or female condoms, among other options.

The new male pill is a hormone-free drug, unlike the female pill.

The pill, YCT-529, is a drug called a retinoic acid receptor-alpha inhibitor, which prevents sperm production by blocking access to vitamin A. Previous studies dating back more than 90 years have shown that depriving mice, rats and monkeys of vitamin A can cause infertility.

Experts from YourChoice Therapeutics said that pre-clinical studies showed YCT-529 was “99 per cent effective and 100 cent reversible with no side effects”. The company said that previous versions of the male pill have attempted to supress the male sex hormone testosterone to prevent sperm production, but this does not stop sperm production completely and has been linked to some complications.

Now, 16 British men are testing the hormone-free pill.

Gunda Georg, regents professor at the University of Minnesota’s College of Pharmacy, who developed the pill, said: "The last innovation in contraception was the birth control pill for women, and that’s more than 60 years ago. The world is ready for a male contraceptive agent, and delivering one that’s hormone-free is simply the right thing to do given what we know about the side effects women have endured for decades from the pill.

"We consciously chose to inhibit the vitamin A signalling pathway in the testis because nearly 100 years of research has validated this pathway and shows that infertility can be reversed easily. Our pre-clinical data is strong, showing that YCT-529 was 99 per cent effective in preventing mouse pregnancies and decreasing monkey sperm counts after two weeks of dosing.

"YCT-529 has also demonstrated a strong safety profile, and full reversibility in mice and monkeys once treatment ended. I commend the YourChoice Therapeutics team for taking this candidate into the clinic and feel confident in its safety profile, which the phase one study will affirm."