Scientists have taken a step closer toward finding the holy grail of male reproductive science. While testing a cancer drug on mice, researchers found that the drug temporarily, but reversibly, halted the production of sperm.
In essence, the drug made the mice’s testicles “forget” how to make sperm. The mice became completely fertile, and even fathered children after they were taken off the drug. The study, which was published in the biology journal Cell, was led by doctors from the Dana-Ferber Cancer Institute, Harvard Medical School, the Baylor College of Medicine in Houston, and the Center for Drug Discovery.
“These findings suggest that a reversible, oral male contraceptive may be possible,” said Dr. James Bradner, who led the study, in an interview with NBC News.
Dr. Bradner produced a molecule called JQ1 that inhibits the production of the testicular protein that is responsible for the production of sperm. The drug was created to fight cancer by inhibiting the production proteins associated with cancerous cells. So far, animal tests for both the sperm-stopping and cancer-fighting applications of the chemical have been promising.
Mice were injected with the solution over an 18-month period. After months of treatment, the mice had their working sperm count reduced to as little as five percent. Once taken off the drug, the mice fathered children, and those children also had kids. There was no evidence the chemical was passed on to any generation of the offspring.
“We have only observed full recovery of fertility in treated males,” the researchers wrote in their study. “We envision that our discoveries can be completely translated to men, providing a novel and efficacious strategy for a male contraceptive.”
“The definitive development of a contraceptive agent will require more chemistry,” said Dr. Bradner in The Atlantic.
Even the most optimistic projections has the drug years away from market as a contraceptive, if it is approved it would have several benefits over the currently available contraceptives. In tests with mice, the effects of the drug were reversible and safe for the offspring of the user. It was orally administered, unlike the surgeries required for a vasectomy and the experimental RISUG (Reversible Inhibition of Sperm and Guidance) treatment.
Even if the drug is approved, it would run into some of the problems that current contraceptives have. Like the female birth control pill, a male birth control pill would offer protection from sexually transmitted diseases. At its current state, the drug would be less effective than condoms, which are 98 percent effective. And it is estimated that up to 16 percent of couples who use condoms as their main form of contraception in a given year will end up becoming pregnant.
JQ1 is beginning human trials for cancer patients, which will give the researchers an opportunity to see the human reproductive effects of the drug for the first time.