Scientists are moving closer to developing a male contraceptive pill, after early trial data showed that a drug known as JQ1 effectively and reversibly inhibits male fertility in mice.

The contraceptive pill for women has been around for decades, and developing an equivalent for men has become somewhat of a holy grail, which could have a significant impact on the rate of unwanted pregnancies, abortions and single parenthood.

But currently there are few targets in clinical trials, and they are testosterone analogs that change the production of endogenous androgen. 

In order to address the current lack alternatives for men, researchers from the Dana-Farber Cancer Institute and Baylor College of Medicine say they are working on the development of small molecules potentially targeting spermatogenic-specific proteins essential for both sperm production and fertility. 

BRDT target

One target they are investigating is the testis-specific protein BRDT, and according to the findings of their trial, published in the journal Cell, direct inhibition of this target "exerts a dose- and time-dependent inhibitory effect on spermatogenesis".

A small-molecule inhibitor called JQ1 has emerged as a lead compound for a new class of drugs that can cross the blood-testis boundary, disrupt spermatogenesis, impair sperm generation and motility, and produce a reversible contraceptive effect in mammals, they note.

"These findings suggest that a reversible, oral male contraceptive may be possible," said Dana-Farber' James Bradner, lead author of the study. "While we will be conducting more research to see if we can build on our current findings, JQ1 shows initial promise as a lead compound for male contraception," he added.