Exciting news in the world of male contraception: a novel gel combining two hormones, segesterone acetate (known as Nestorone) and testosterone, is showing promising results. According to a new study, this gel suppresses sperm production faster than other experimental hormone-based methods for male birth control.
Results from this ongoing multicenter phase 2b clinical trial will be shared at ENDO 2024, the Endocrine Society’s annual meeting in Boston.
“The development of a safe, highly effective, and reliably reversible contraceptive method for men is an unmet need,” says Dr. Diana Blithe, the senior researcher and chief of the Contraceptive Development Program at the National Institutes of Health (NIH). “While some hormonal agents have shown potential for male contraception, their slow onset in suppressing sperm production is a limitation.”
Funded by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, the study included 222 men who used the contraceptive gel daily for at least 3 weeks. The gel, applied once daily to each shoulder blade, contained 8 milligrams of segesterone acetate and 74 milligrams of testosterone. Notably, segesterone acetate is also an ingredient in the Annovera vaginal birth control ring.
Researchers measured sperm suppression by conducting sperm count tests every 4 weeks. An effective contraceptive threshold was determined to be 1 million or fewer sperm per milliliter of semen.
By week 15, 86% of participants had reached this sperm count. Remarkably, the median time to suppression was less than 8 weeks. In contrast, previous studies of male hormonal contraceptives administered via injections showed a median suppression time of 9 to 15 weeks.
“A more rapid suppression may make this drug more appealing to potential users,” says Blithe.
While testosterone treatment alone can decrease sperm production in about 15 weeks, the addition of segesterone acetate significantly speeds up the process and allows for a lower dose of testosterone. This daily gel regimen maintains blood testosterone levels in the physiological range, ensuring normal sexual function and other androgen-dependent activities.
The sperm suppression phase of this international trial is now complete. The study will continue to evaluate the contraceptive’s overall effectiveness, safety, acceptability, and the reversibility of its effects after stopping treatment.
This development marks a significant step forward in male contraception, potentially offering men a new, efficient, and reliable birth control option.
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