Move over, ladies. The quest for male birth control is heating up, and it’s not just about gels and pills—it’s about rewriting the rules of reproductive responsibility.
This month researchers unveiled results of phase II clinical trials that show NES/T, an alcohol based gel much like an after shave balm, containing a mix of testosterone and nestosterone, successfully and reversibly suppresses sperm production. As NES/T progresses to phase IIb clinical trials, US government scientists are hopeful that we may soon see this gel-based contraceptive pass the next hurdle—pregnancy prevention.
The hormonal treatment developed by US government scientists from the National Institute of Child Health and Human Development (NICHD) and the Population Council lowers sperm counts to contraceptive levels, 1 million or fewer sperm per milliliter of semen. Absorbed through the skin, the hormones will pass into the bloodstream and work their way through the body. This magic lotion potion, splashed on the shoulders, could suppress sperm counts faster than a cold shower.
NES/T, is making history as the first product of its kind to advance past initial clinical trials. So far early phase IIb clinical results have been promising, with couples reporting positive experiences using the gel, and successful pregnancies after discontinuing treatment. Could we be about to see the first male hormonal birth control option hit phase III clinical trials?
Trying the “gel-on” method
The gel, applied daily to the shoulders, has shown remarkable effectiveness in suppressing sperm count in the phase II trial. Two hundred twenty-two men applied the gel once a day to their arms and shoulders for a duration of 52 weeks in the phase II trial. Researchers measured sperm counts at 4-week intervals and considered a count of 1 million or fewer sperm per milliliter of semen to be effective for contraception. After 12 weeks, 86% of participants achieved sperm suppression to a level considered effective for contraception. This rapid effectiveness is a significant improvement over previous attempts at hormonal male contraception, which often required higher doses and led to undesirable side effects.
The gel’s success is attributed to its unique combination of testosterone and Nestorone, a synthetic hormone already used in female contraceptives. This combination allows for lower testosterone levels, minimizing side effects while still maintaining normal sexual function.
Low count, high hopes
Researchers are now moving on to the next phase of the trial, focusing on the gel’s effectiveness in preventing pregnancy. In this Phase IIb study, 420 couples across 15 sites will participate in a four-phase process. An initial screening phase, to confirm eligibility, will be followed by a 20-week suppression phase. Men will use the gel each day until their sperm count reaches a target low level. Entering the evaluation phase, they will continue to use the gel for a year to test the gel’s ability to prevent pregnancy when used as the sole contraceptive method. Finally, the men will stop using the gel and a 24-week recovery phase will allow researchers to monitor the men’s sperm counts as they return to normal after gel use is discontinued.
The male participants will apply the NES/T gel daily and attend monthly visits for monitoring and support. Their female partners will also be contacted monthly and have in-person visits every three months.
Will the gel deliver?
The lack of federally approved male contraceptives despite decades of research highlights the challenges in securing funding for large-scale trials. However, experts remain hopeful that the success of this gel and other promising methods will usher in a new era of reproductive options for men.
Dr. Diana Blithe, chief of the Contraceptive Development Program at the National Institutes of Health (NIH) stated in a recent press release, “The development of a safe, highly effective and reliably reversible contraceptive method for men is an unmet need.” “While studies have shown that some hormonal agents may be effective for male contraception, the slow onset of spermatogenic suppression is a limitation.”4
The current phase of the international trial has successfully demonstrated the gel’s ability to suppress sperm production. The study is now progressing to assess its effectiveness as a contraceptive, its safety profile, how well it’s tolerated by users, and the reversibility of its effects once treatment is stopped.
The stakes here are high. It’s not just about giving men more choices, it’s about empowering couples to share the responsibility of family planning. So, gentlemen, get ready. The future of birth control might just be in your hands…or rather, on your shoulders.
References
- Study of Daily Application of Nestorone® (NES) and Testosterone (T) Combination Gel for Male Contraception (no date) Clinicaltrials.gov. Available at: https://clinicaltrials.gov/study/NCT03452111 (Accessed: 13 September 2024).
- Spotlight: One Year and counting: Male birth control study reaches milestone (no date) Eunice Kennedy Shriver National Institute of Child Health and Human Development. Available at: https://www.nichd.nih.gov/newsroom/news/080222-NEST (Accessed: 13 September 2024).
- Endocrine Society (2024) New male birth control gel takes effect sooner than similar contraceptive methods, Endocrine Society. Available at: https://www.endocrine.org/news-and-advocacy/news-room/2024/endo-2024-press-blithe (Accessed: 23 September 2024).