Phase 2 trials test a drug for both efficacy and safety, usually in hundreds of volunteers, and look for harmful or unpleasant drug reactions. An earlier 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 supported by the World Health Organization and CONRAD, a non-profit reproductive health organization.
For the gel trial, side effects may include weight gain and mood problems. “There will be a small percentage of men who will have some kind of side effect, but we know that’s true for many different female contraceptives as well,” says Creinin. “We’re not looking for the product that works perfectly for every man; We’re looking for the product that works really well for the most people.”
Next, the gel will need to be tested in a larger phase 3 clinical trial, which will likely include thousands of couples. It will also require a pharmaceutical company to manufacture and bring it to market, as the NIH and the Population Council lack the capacity to market drugs. (The NIH is also sponsoring early-stage trials of hormone pills designed to lower sperm counts by suppressing testosterone.)
Funding has been a major obstacle for male contraceptives: in recent years, pharmaceutical companies have not been involved in their research and development. Instead, philanthropic organizations and the public sector have been the main funders of these efforts.
But investment firms like Rhia Ventures, a San Francisco-based firm focused on reproductive health, are trying to turn that problem around. CEO Erika Seth Davies says it’s important that there are non-hormonal forms of birth control available to men. “In this post-Roe world, making sure there’s a robust supply of contraception and access to contraception is going to be essential,” she says. “We’re trying to make sure there are more options available in the market, because the responsibility for preventing “Pregnancy has been put squarely on women’s shoulders for so long.”
In addition to funding female contraceptive efforts, his company is investing in Contraline, a Virginia-based biotech company that is developing a reversible, non-hormonal form of male birth control. Contraline’s method involves a permeable hydrogel that is injected into the vas deferens, the pair of tubes in the male reproductive system that carry sperm. The gel is designed to block sperm without affecting sensation or ejaculation. The company is conducting a small phase 1 trial in Australia to test the safety of the approach.
Your Choice Therapeutics and Eppin Pharma are also pursuing non-hormonal forms of male contraception. Your Choice is developing a pill designed to block the development of sperm cells, while Eppin’s method is designed to prevent sperm from fertilizing an egg. But these companies have yet to move on to human testing.
One of the hurdles for all these efforts will be getting regulatory approval for any product that passes Phase 3 trials. No male contraceptive drug has ever reached this phase, so the Food and US Medicines will have to decide what level of risk is acceptable. Women’s birth control pills cause about one death for every 200,000 users, mostly from blood clots that can arise from using the pills. Men have none of the physical risks of pregnancy, so working out that risk-benefit calculation will be tricky, Armory says. He believes this is 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 believes it is time for the government to increase funding for male contraception research. “We are on the precipice of change in social norms,” he says. “Whatever is the first product on the market will be a social game changer.”