A New Hope in the Search For a Male Contraceptive

Hallelujah and praise the Norns, it seems there might finally be an effective form of AMAB birth control on the horizon. It’s fast-acting, effective, and without the terrible side effects that got the last for-AMAB-use contraceptive cancelled! It’s a dream come true, especially for potentially fertile couples where hormonal birth control is off the table for the AFAB partner, but neither person is willing to permanently end their fertility yet.

The potential contraceptive was discovered almost by accident in 2018, while testing an experimental drug for the treatment of eye disease. It works by stopping sperm development in its tracks. But the effect only lasts for a limited time: two and a half hours in mice, with twelve hours projected for a human being. This allows normal sperm development to resume in a same-day window. Best of all, no hormonal fiddling is required, as the drug instead targets an enzyme, soluble adenylyl cyclase (sAC). It seems sAC can be safely blocked for discrete periods of time without any ill effects on the subject.

How does it work?

The idea came to Melanie Balbach, then a postdoctoral scientist at Weill Cornell Medicine, when a colleague asked for her assistance during the animal testing stage of his project. Though the drug was intended to treat eye disease, Balbach was aware that the biochemical process it targeted is crucial to male fertility. She agreed to participate in exchange for being allowed to examine the impact on the test mice’s fertility. The results were revolutionary: total sperm immobility. One colleague described Balback’s findings as “the holy grail” in the search for an effective male contraceptive.

The two most exciting parts of Balbach’s discovery are the apparent safety and the reversibility of the contraceptive in question. Most previous research into AMAB contraceptives has been hormone-based—something which, due to the cycle of sperm development, can only be used as a long-term method. These methods also take several weeks to come into effect. Hormonal contraception can be dangerous, too, though still less dangerous than pregnancy itself. Still, there’s a small percentage of serious and even fatal outcomes for users of established AFAB-specific methods.

However, because pregnancy and its ensuing risk factors aren’t a possibility for AMAB patients, the acceptable level of risk for an AMAB hormonal contraceptive is set lower than standard for AFAB birth control. There’s no equivalent to the dangers of pregnancy to offset it. Add in the fact that research into AMAB hormonal contraceptives are decades behind AFAB, and the severe psychiatric effects found in a small percentage of users in the cancelled study that exceeded even what would be permitted in an AFAB pill, and a safe, effective hormonal method could still be a decade or more away.

Meanwhile, Balbach’s proposed contraceptive would be an “on demand” method. The contraceptive allows AMAB people and their partners to have spontaneous, protected sex, and then immediately begin trying to conceive the next day if they decided that’s what they want. Better still, it seems the chance of negative side effects is minimal. The study which inspired Balbach to try her experiment featured two cis men who were missing the gene which allows the body to produce sAC. The primary negative outcomes were infertility and an increased risk of kidney stones—something that’s likely a result of long-term absence or inhibition of sAC, rather than the result of turning it off and on again (so to speak) for short periods of time.

A long time coming

Infuriatingly, sAC’s impact on male fertility has been known for some time—almost twenty years, in fact. However, drug companies almost immediately lost interest in it, due in large part to a prevailing belief that cis men just didn’t want pharmacological birth control that they were responsible for taking. Add in concerns about inhibiting these kinds of enzymes in case of unforeseen side effects, and sAC was put on the back-burner until Balbach had the opportunity to test her hypothesis.

Now, with the loss of Roe vs Wade driving interest in AMAB specific birth control, the environment is very different. The co-directors of the Weill Cornell laboratory, Jochen Buck and Lonny Levin, have enough confidence in Balbach’s discovery that they’ve founded a startup, Sacyl Pharmaceuticals. The startup will try and produce a viable AMAB birth control pill.

Unfortunately, the contraceptive is still a few years out from human testing. We’re all going to be stuck with the contraception we’re using now for a while longer. But still, it’s an exciting discovery. And in the meantime, another non-hormonal contraceptive for AMAB users is scheduled for testing later this year. So an alternative may become a possibility sooner than we think.

(Featured image: Artem Podrez via Pexels)