New male contraceptive gel works faster than similar contraceptive methods
Last reviewed: 14.06.2024
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Results from the ongoing multicenter phase 2b clinical trial will be presented Sunday at ENDO 2024, the annual meeting of the Endocrine Society in Boston.
“Development of a safe, highly effective, and reliably reversible method of contraception for men remains an unmet need,” said senior investigator Diana Blythe, Ph.D., director of the Contraceptive Development Program at the National Institutes of Health (NIH) in Bethesda, Maryland. "Although studies have shown that some hormonal agents may be effective for male contraception, the slow onset of suppression of spermatogenesis is a limitation."
The study included 222 men who completed at least 3 weeks of daily use of the contraceptive gel. The gel contained 8 milligrams (mg) of segesterone acetate and 74 mg of testosterone. Segesterone acetate is an ingredient in the Annovera vaginal birth control ring. The men applied the gel daily to each shoulder blade.
In the early stages of the study, researchers measured suppression of sperm production by conducting semen tests at 4-week intervals. The threshold considered effective for contraception was 1 million or fewer sperm per milliliter of semen, Blythe noted.
The majority of study participants (86%) achieved this sperm count by week 15, the researchers reported. In these men, sperm production was suppressed after an average of less than 8 weeks of segesterone-testosterone treatment. Blythe said previous studies of injectable male hormonal contraceptives showed an average time to suppress sperm production of 9 to 15 weeks.
“A faster suppression time may increase the appeal and acceptability of this drug to potential users,” Blythe said.
Testosterone treatment by itself reduces sperm production, with an average time of 15 weeks, but adding segesterone acetate speeds up this process and reduces the dose of testosterone required to suppress sperm production compared with testosterone alone, she noted. In a daily regimen of segesterone-testosterone gel, blood testosterone levels are maintained within the physiological range to support normal sexual function and other androgen-dependent activities.
The sperm suppression phase of the international Phase 2b trial of segesterone-testosterone gel has been completed. The study is ongoing to test contraceptive effectiveness, safety, acceptability, and reversibility of contraceptive effects after treatment discontinuation.