On-demand pill for men: US researchers win $8.2 million for safety testing

Pharmacologists Jochen Buck and Lonny Levin of Weill Cornell Medicine in New York are receiving $8.2 million over four years from the US National Institute of Child Health and Human Development (NICHD), the health portal News-Medical reported on 22 October; Newsweek covered the project on 23 October. It is the third such award since 2020. The money will fund toxicology and safety studies required before a first phase 1 clinical trial in healthy men.

The compound inhibits the enzyme soluble adenylyl cyclase (sAC) in sperm and temporarily immobilises them. “We've developed an on-demand contraceptive pill that men would take 30 minutes before having sex,” Buck said, according to News-Medical. The goal is a six-to-eight-hour window of protection, after which fertility returns. A study published in Nature Communications in 2023 found that blocking sAC rendered sperm immobile and prevented pregnancies in preclinical models; according to Newsweek, no side effects were seen in the animal studies. Buck, Levin and their colleague Peter Meinke co-founded the company Sacyl Pharmaceuticals.

There is still a long way to go: the compound has not yet been tested in humans. The researchers hope to begin human studies in less than two years, while efficacy testing with couples would take several years. Steven L'Hernault of Emory University told Newsweek that sAC also plays a role in other tissues such as the eye, which raises “some concerns”. Yale researcher Jean-Ju Chung urged patience, noting that the field has been set back before by promises of a male pill within five years.