Scientists are trying to make a birth control pill for men and they might have made it. In new preliminary research, a team says they’ve developed a non-hormonal form of male birth control, one that kept lab mice sterile for four to six weeks with seemingly no side effects. Early human trials will begin at the end of the year.
The research is conducted by the University of Minnesota, which says it works by targeting how our bodies interact with vitamin A, known to be essential to fertility in mammals. Diets deficient in vitamin A have been linked to sterility. After a lengthy search, they found an experimental compound that blocks a protein responsible for binding to a form of vitamin A (retinoic acid) in our cells, known as retinoic acid receptor alpha (RAR-?). RAR-? is one of three proteins with a similar function, and the hope is that its selective blocking is enough to induce long-lasting but reversible sterility while causing little to no off-target effects elsewhere.
“Since men do not have to suffer the consequences of pregnancy, the threshold for side effects from birth control pills is rather low,” lead researcher Md Abdullah Al Noman told Gizmodo in an email. “That’s why we’re trying to develop non-hormonal birth control pills to avoid hormonal side effects.”
The compound is called GPHR-529 and is working as intended. In new data presented Wednesday at the spring meeting of the American Chemical Society, the team found that male mice dosed with the treatment for four weeks consistently experienced a sharp drop in sperm count and became sterile.
“This all looks promising so far. But clinical trials are the definitive test for the safety of any drug candidate,” Noman noted.
The team has since licensed GPHR-529 to the company YourChoice Therapeutics for further development. The UMN team is also still working to identify other promising candidates, both in case GPHR529 doesn’t pan out and to improve on their existing concept, which could allow them to get the same contraceptive effect at a lower dose.
Another male conceptive gel NES/T is also in the works. It lowers levels of sperm and natural testosterone but then supplements its own testosterone to reduce side-effects. A larger scale Phase IIb trial of the gel is expected to be completed in early 2023, though more trials will be needed for FDA approval.