A phase 2 clinical trial has revealed promising results for a novel hormonal gel as a potential male contraceptive. The gel, containing testosterone and Nestorone, a synthetic progestin, demonstrated effective sperm suppression in a majority of participants, offering a potential new option for male birth control. The trial, presented at the Endocrine Society’s conference in Boston, marks a significant step forward in the development of male contraceptives, an area that has seen limited progress for decades.
The trial involved 222 men aged 18 to 50 who applied 5 milliliters of the gel daily to their shoulder blades. After 12 weeks, 86% of participants achieved sperm suppression, defined as having less than 1 million sperm per milliliter of semen. The average time to reach effective contraception was eight weeks, which was faster than anticipated. According to Diana Blithe, chief of the NIH’s Contraceptive Development Program, this rapid suppression is an encouraging sign, as previous attempts have taken longer to reach similar sperm levels.
The combination of testosterone and Nestorone in the gel is designed to suppress sperm production without negatively impacting sex drive or causing other side effects. Nestorone, already used in vaginal contraceptive rings, helps to reduce the amount of testosterone needed, minimizing potential adverse effects. So far, participants in the clinical trial have maintained normal sexual function with low blood levels of testosterone.
Researchers are now monitoring the gel's effectiveness in preventing pregnancy. Participants are required to be in committed, monogamous relationships and must agree to use the gel as their only form of birth control, engaging in sexual activity at least once a month for a year. Sperm counts are regularly tested to predict fertility, with low sperm counts indicating a reduced chance of pregnancy.
Despite the encouraging results, the path to FDA approval and widespread availability faces financial hurdles. Daniel Johnston, chief of the National Institute of Child Health and Human Development’s Contraception Research Branch, noted that a lack of funding has hindered the progress of male contraceptive development for 50 years. He hopes that the approval of one male birth control drug would incentivize pharmaceutical companies and investors to allocate more resources to this area.
Non-Hormonal Alternatives
In addition to the hormonal gel, several non-hormonal male contraceptive options are under development. YourChoice Therapeutics reported positive results from a small trial of their non-hormonal pill, YCT-529, which blocks the vitamin A receptor crucial for male fertility. Contraline is also developing ADAM, an injectable gel that blocks the vas deferens, offering a long-acting reversible contraceptive method. Next Life Sciences is working on a similar approach called Plan A or Vasalgel.
Growing Demand for Male Contraception
Surveys indicate a growing interest among men in using contraception. A 2023 survey published in Contraception found that three-quarters of male respondents were willing to try new contraceptive methods. Heather Vahdat, executive director of the Male Contraceptive Initiative, noted an increase in interest since the overturning of Roe v. Wade, with more individuals seeking to participate in clinical trials.
While vasectomies are a permanent solution, these new contraceptive approaches are designed to be reversible, allowing men to regain their fertility when desired. The development of diverse male contraceptive options aims to provide couples with more choices and shared responsibility in family planning.
Financial Obstacles
Despite the promising research, significant financial investment is needed to advance these contraceptives through the FDA approval process. Nguyen, an associate professor of obstetrics and gynecology at the University of Southern California, emphasized the necessity of an industry partner to fund the next-stage trials for the hormonal gel. The future of male contraception hinges on overcoming these financial obstacles and recognizing the growing demand for male birth control options.
