A new male contraceptive pill, YCT-529, has shown promising results in early human trials, demonstrating reversible infertility in male mice and nonhuman primates.Developed by yourchoice Therapeutics, the drug works by targeting the retinoic acid receptor alpha (RARα), a key protein involved in sperm production. Researchers identified this target by examining the receptor’s structure when bound to it’s natural ligand and by testing various molecules for their ability to block this interaction.
In preclinical studies with male lab mice,YCT-529 induced reversible infertility within four weeks,achieving 99% effectiveness in preventing pregnancy in females mated with treated males. Fertility was restored in the mice four to six weeks after discontinuing the drug.Similar outcomes were observed in nonhuman primates,where sperm counts significantly decreased within two weeks of treatment and fully recovered 10 to 15 weeks after cessation.
These preclinical findings paved the way for a recent clinical trial involving 16 male participants aged 32 to 59. To ensure safety, all participants had previously undergone vasectomies, as a precautionary measure against any potential lasting effects on fertility, according to Nadja Mannowettez, co-founder and chief science officer of YourChoice Therapeutics.
Participants were divided into groups receiving either placebo pills or low or high doses of YCT-529. most participants took the pill after fasting, while a subset also took it after a large meal to assess the impact on drug absorption. The trial indicated that the drug reached adequate levels in the body across all tested doses and conditions. Mannowettez anticipates that the final approved dosage would likely be around 180 milligrams, the highest dose tested.
both animal and human trial data suggest that the pill would be taken onc daily, though further trials are needed to confirm this dosing regimen. While no significant side effects were reported in this initial small-scale trial, larger future studies will be necessary to monitor for any adverse effects.
The study authors noted that the positive outcomes of this first clinical trial have led to a second trial, currently underway. This ongoing trial will administer YCT-529 to men for 28 and 90 days to further evaluate its safety and effects on sperm parameters. This subsequent trial also includes men who have had vasectomies or have made a firm decision against fathering children.
