On The Horizon: A Contraceptive Gel for Men

By Jane Farrell

Researchers are working on a new contraceptive gel – for men.

A clinical trial, funded by the National Institutes of Health (NIH), will conduct a study of 420 couples around the world.

The gel, called NES/T, includes the progestin compound segesterone acetate (brand name Nestorone), in combination with testosterone. Men who participate in the study will apply it to their back and shoulders once a day. It is then absorbed into the skin. NIH officials said that the progestin blocks natural testosterone production in the testes, reducing sperm production to low or nonexistent levels. The replacement testosterone will help maintain normal sex drive and other functions that are dependent on adequate testosterone levels in the blood.

NIH experts said the possibility of a new, reversible contraception method for men would be welcome. (See our story, “What You Need to  Know About Birth Control.”)

“Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms,” said study investigator Diana Blithe, Ph.D., chief of the Contraceptive Development Program NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). “A safe, highly effective and reversible method of male contraception would fill an important public health need.”

Couples in the global study, funded by the NIH, will rely on the gel as their only method of contraception.

Male volunteers will use the NES/T gel daily for four to 12 weeks to determine whether they tolerate the formulation and to guard against 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 only method of contraception. Men will remain in the study for observation for an additional 24 weeks after they discontinue the formulation.

The gel formulation was developed by the Population Council and the NIH’s NICHD institute. The Population Council will collaborate with NIH to conduct the study in NICHD’s Contraceptive Clinical Trials Network.