A promising male contraceptive: Effective and side-effect free?

Male contraception could soon experience a decisive breakthrough thanks to a new non-hormonal method that proves effective and reversible in mice. A team of researchers from Baylor College of Medicine has developed a promising compound, CDD-2807, that could transform the way male contraception is considered. The study was published in the journal Science.


Human trials are still far off, but the results obtained in rodents are encouraging. The compound, named CDD-2807, demonstrated its ability to penetrate the bloodstream, cross into the testes, and inhibit hyperactivity of sperm cells. In a study conducted on a dozen male mice, the subjects received daily injections of CDD-2807 for 21 days.

During this period, none of the treated males fathered any offspring despite regular mating with females. After 53 days without the treatment, the males regained their fertility. Researchers observed that the sperm count, motility, and hyperactivity were significantly reduced in treated mice compared to control groups.

"We are thrilled to see that the mice showed no signs of toxicity following CDD-2807 treatment, that the compound did not accumulate in the brain, and that the size of the testes was unaffected," stated pathologist Courtney Sutton. "The contraceptive effect was reversible. After a period without CDD-2807, the mice regained their sperm mobility and count, becoming fertile again."

CDD-2807 stands out for its ability to inhibit a protein known as serine/threonine kinase 33 (STK33), which is widespread in the testes of mammals. Studies have shown that sperm cells from humans and mice lacking the STK33 gene, which codes for the same protein, exhibit abnormalities leading to sterility, without causing other health issues.

According to Martin Matzuk, a reproductive biologist at Baylor, STK33 is a viable target with minimal safety risks for male contraception. Since the introduction of the first female contraceptive pill nearly 60 years ago, numerous new options have appeared for women, ranging from oral pills to implantable devices. In contrast, the last innovative male contraceptive dates back to the 1980s with the minimally invasive vasectomy.

Research on a reversible, non-invasive male contraceptive method has long been a challenge. Previous attempts have not reached widespread clinical application. In 2016, a clinical trial for male contraception was halted due to negative side effects, despite concerns about a double standard since similar effects are tolerated for female contraceptives.

The development of male contraceptives must overcome significant obstacles, including the increased rigor of current clinical research processes. While this rigor improves drug safety, it also lengthens the time required to bring them to market. However, the team at Baylor College of Medicine is determined to continue research on CDD-2807 and plans to test the compound on non-human primates.