• Posted May 24, 2024

New Steps Towards a Male Birth Control Pill

For decades, the responsibility for birth control has fallen largely on women, but new research suggests a birth control pill for men might one day become a reality.

How does it work? It targets a protein required for fertility, scientists report.

The protein, called serine/threonine kinase 33 (STK33), is enriched in the testicles and is specifically required to create functional sperm, they explained.

A drug that inhibits STK33, called compound CDD-2807, blocked the ability of male lab mice to fertilize female mice, researchers reported May 23 in the journal Science.

“We were pleased to see that the mice did not show signs of toxicity from CDD-2807 treatment, that the compound did not accumulate in the brain and that the treatment did not alter testis size,” said researcher Courtney Sutton, a postdoctoral fellow in pathology at Baylor College of Medicine in Houston.

“Importantly, the contraceptive effect was reversible,” Sutton added in a Baylor news release. “After a period without compound CDD-2807, the mice recovered sperm motility and numbers and were fertile again.”

Previous research had shown that naturally occurring mutations in STK33 leads to infertility in both mice and men by causing abnormal sperm with poor movement. These mutations cause no other health problems.

“STK33 is therefore considered a viable target with minimal safety concerns for contraception in men,” said researcher Dr. Martin Matzuk, director of the Center for Drug Discovery at Baylor.

The research team screened billions of different compounds to discover ones that would effectively inhibit STK33, researchers said. They then generated modified versions of the most effective compounds to make them more stable and potent.

“Among these modified versions, compound CDD-2807 turned out to be the most effective,” said lead researcher Angela Ku, a staff scientist with Baylor.

The researchers then tested different doses and treatment regimens of CDD-2807 in lab mice, to see how well it worked.

“In the next few years, our goal is to further evaluate this STK33 inhibitor and compounds similar to CDD-2807 in primates, to determine their effectiveness as reversible male contraceptives,” Matzuk said.

More information

Planned Parenthood has more on birth control.

SOURCE: Baylor College of Medicine, news release, May 23, 2024