Phase 2 trials test a drug for both efficacy and safety, typically in hundreds of volunteers, and look for harmful or unpleasant drug reactions. A previous Phase 2 trial of an injectable hormone-based contraceptive for men was stopped in 2011 because the drug had too many side effects, including muscle pain, increased libido, acne, and depression. Its development was backed by the World Health Organization and CONRAD, a reproductive health nonprofit.
For the gel trial, side effects might include weight gain and mood issues. “There are going to be a small percentage of men that are going to have some kind of side effects, but we know that’s true for lots of different female contraceptives as well,” Creinin says. “We’re not looking for the product that will work perfectly for every single man; we’re looking for the product that is going to work very well for the majority of people.”
Next, the gel will need to go through testing in a larger Phase 3 clinical trial, which will likely include thousands of couples. It will also need a pharmaceutical company to manufacture and bring it to market, since NIH and the Population Council don’t have the ability to commercialize drugs. (The NIH is also sponsoring early-stage trials of hormonal pills designed to lower sperm count by suppressing testosterone.)
Financing has been a major hurdle for male contraceptives: In recent years, pharmaceutical companies haven’t been involved in their research and development. Instead, philanthropic organizations and the public sector have been the main funders of such efforts.
But investment firms like Rhia Ventures, a San Francisco-based company focused on reproductive health, are trying to turn that problem around. CEO Erika Seth Davies says it’s important that nonhormonal forms of birth control are available for men. “In this post-Roe world, making sure that there is a robust offering of contraception and access to contraception is going to be imperative,” she says. “We’re trying to make sure that there are more options available on the market, because the responsibility for pregnancy prevention has been squarely placed on women’s shoulders for so long.”
In addition to funding female contraceptive efforts, her firm is investing in Contraline, a Virginia-based biotech company that’s developing a reversible, nonhormonal form of male birth control. Contraline’s method involves a permeable hydrogel that’s injected into the vas deferens, the pair of tubes in the male reproductive system that transport sperm. The gel is designed to block sperm without affecting sensation or ejaculation. The company is running a small Phase 1 trial in Australia to test the safety of the approach.
Your Choice Therapeutics and Eppin Pharma are also pursuing nonhormonal forms of male contraception. Your Choice is developing a pill meant to block sperm cell development, while Eppin’s method stops sperm from fertilizing an egg. But those companies have yet to move into human testing.
One of the hurdles for all of these efforts will be getting regulatory approval for any product that clears Phase 3 trials. No contraceptive drug for men has ever gotten to that stage, so the US Food and Drug Administration will have to decide what level of risk is acceptable. Women’s birth control pills result in about one death per 200,000 users, primarily from blood clots that can arise from using the pills. Men don’t have any of the physical risks of pregnancy, so calculating that risk-benefit calculation will be tricky, says Armory. He thinks that’s one reason pharmaceutical companies have been reluctant to get involved in male birth control. But ultimately, more contraceptive options will benefit everyone, he says: “The market is huge—we’re talking about potentially millions of men.”
With the fall of Roe, Creinin thinks it’s time for the government to increase funding for male contraception research. “We are on the precipice of change in societal norms,” he says. “Whatever product is first to market is going to be a social game changer.”
