In recent years, researchers have developed a variety of new contraceptive options for women. From intrauterine devices to hormone injections, there are more ways for women to take birth control than ever. The search for male contraceptives, on the other hand, has been far more elusive.
Most male birth control options have been experimental, or invasive, or both.
Take Vasalgel, for example. This is a nonhormonal contraceptive that’s currently only available to men in Indiana through clinical trials. As its name suggests, Vasalgel is a polymer gel that is injected into the vas deferens to block the flow of sperm out of the testicles. It was based on a similar product which has been in clinical trials for more than 15 years. If men want to restore their fertility, a second injection is used to flush the gel out of the vas deferens.
A second, even more experimental option is Bimek SLV. This is a mechanical birth control switch invented by a carpenter in Germany. It’s surgically implanted behind the testicles, and acts as a temporary vasectomy that can be turned on and off. Flip the switch on, and a mechanism blocks the vans deferens, rendering the man temporarily infertile. Turn it off, and the flow of sperm is restored. It’s effective, but not exactly ideal. Plus, it’s not expected to be out of clinical trials until at least 2018.
Thanks to the efforts of a group of researchers at the University of Minnesota, however, men may soon be able to take responsibility for their reproductive health without having to go under the knife. The researchers presented their work last week at the National Meeting & Exposition of the American Chemical Society (ACS).
The researcher team’s leader, Gunda I. Georg, Ph.D., explained that in order to be successful, a male oral contraceptive must meet several criteria. It must work quickly, and it should not have a negative impact on libido. It should also be safe, even if taken for decades. Finally, its effects should be easily reversible and cause no lingering negative effects on sperm health.
“That’s a very high bar for bringing a male contraceptive to market,” explained Georg in her presentation. “It would be wonderful to provide couples with a safe alternative because some women cannot take birth control pills,” she continued. Oral contraceptives can be especially dangerous for women with high blood pressure or heart problems.
So how might the male contraceptive work?
Rather than focusing on hormone supplements, Georg and her team looked instead at chemical compounds that block retinoic acid receptors. One of these receptors – the alpha receptor – is tied to sperm production. Previous studies have demonstrated that animals with alpha receptor deficiencies stop producing sperm, but remain otherwise healthy.
Georg’s team concluded that if they could isolate a chemical compound that would target and suppress the alpha receptor, it could act as an effective, reversible form of birth control. The trick is finding a compound that will target the alpha receptor, but not other retinoic acid receptors. If the compound unintentionally interacts with other receptors, it could cause severe negative side-effects.
Georg and her team have been working to hone a chemical compound from Bristol-Myers Squibb that modifies the alpha receptor to stop sperm production. Currently, they’re conducting tests to ensure that the chemical only binds to the alpha receptor. They’re also altering the chemical to increase its solubility so that it can be taken orally.
There’s still significant work to be done before the chemical will be ready to go to market, but Georg expects that the team will have a pill ready for animal trials within the next six months.