NIH to evaluate effectiveness of male contraceptive skin gel

The gel formulation includes the progestin compound segesterone acetate, in combination with testosterone, and is applied to the back and shoulders and absorbed through the skin.

“Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms,” said study investigator Diana Blithe, chief of NICHD’s Contraceptive Development Program. “A safe, highly effective and reversible method of male contraception would fill an important public health need.”

The gel formulation, called NES/T, includes the progestin compound segesterone acetate (brand name Nestorone), in combination with testosterone. It is applied to the back and shoulders and absorbed through the skin. The progestin blocks natural testosterone production in the testes, reducing sperm production to low or nonexistent levels. The replacement testosterone maintains normal sex drive and other functions that are dependent on adequate blood levels of the hormone.

Researchers plan to enroll approximately 420 couples into the study. Male volunteers will use the NES/T gel daily for 4 to 12 weeks to determine whether they tolerate the formulation and to ensure they do not experience unacceptable side effects. If sperm levels have not adequately declined, they will continue to use the formulation for up to 16 weeks. Once their sperm levels have declined to a threshold sufficient for contraception, they will enter the efficacy phase, which will evaluate the ability of the formulation to prevent pregnancy. This phase will last for 52 weeks, and the couple will rely on the male partner’s application of the gel as the sole method of contraception. Males will remain in the study for observation for an additional 24 weeks after they discontinue the formulation.