Male Contraceptive Pill Enters First Trial

A brand new type of male contraceptive has begun its first trial, and unlike many contraceptives, doesn't involve any hormones.

A group of 16 British men are involved in the trial of the pill, which is currently named YCT-529 and is the first ever hormone-free male birth control pill to be tested in humans.

This pill—manufactured by YourChoice Therapeutics and developed by drug development company Quotient Sciences—works by preventing access of the sperm production process to vitamin A, which in turn prevents sperm from being manufactured in the seminiferous tubules in the testes.

The YCT-529 pill prevents the sperm from being both formed and released via the blocking a receptor of retinoic acid, a form of vitamin A. Vitamin A deficiencies have been previously found to lead to infertility in mice, monkeys and rats.

"Researchers have understood for decades that vitamin A is essential for male fertility. YCT-529 is a retinoic acid receptor-alpha [RAR-a] inhibitor that prevents the production of sperm cells in the testes as well as their release by blocking RAR-alpha (one of three nuclear receptors that bind retinoic acid, a form of vitamin A)," Gunda Georg, regents professor at the University of Minnesota's College of Pharmacy and one of the developers of the new pill, told Newsweek.

"In mice mating studies, YCT-529 was 99 percent effective and reversible. Studies in monkeys also showed a reversible reduction of sperm counts. Neither the mice nor the monkeys showed any side effects," Georg said.

Additionally, the mice were found to be fertile again after four to six weeks.

Other previous forms of birth control pill for men worked by suppressing testosterone, which did not lead to effective blocking of sperm production and led to issues in regaining full fertility and side effects such as weight gain, acne, aggression and decreased libido. These are also all side effects of hormonal birth control options for women, which use estrogen and progesterone hormones to prevent ovulation.

In 2016, a phase II trial of a male injectable birth control study that had been commissioned by the World Health Organization was stopped due to the side effects, according to the results in a Journal of Clinical Endocrinology and Metabolism paper. Other male contraceptive methods that are being tested include hormonal male birth control pill called dimethandrolone undecanoate, which is undergoing trials, and a hormonal birth control gel, which made it to phase III trials in 2022.

This trial is hoped to be the first step towards men and women taking contraceptives more equally. According to a 2021 study published in the Journal of Sex Research, between 34 and 82.3 percent of men are willing to take male contraceptives.

"While most men view pregnancy prevention as a shared responsibility, they have few options to participate," YourChoice Therapeutics executive director Heather Vahdat said in a statement. "The first human study for a hormone-free male birth control pill is a long-awaited milestone and a landmark achievement in the quest for reproductive autonomy. While significant work lies 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 childbearing, a kind of health equity we believe is long overdue."

The phase I trial is expected to end in June 2024, after which more phases will be needed before the pill makes it to the public.

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