New Contraceptive Options for Men

Several male contraceptives are in different stages of investigation. A new form of nonhormonal male contraception is being studied in humans. The Intra Vas Device (IVD) is a long-term contraceptive designed as an alterative to vasectomy. The device blocks sperm by plugging the vas deferens, in contrast to vasectomy, in which this tube is simply cut.

The second trial in humans now under way will enroll 90 men. In the pilot study, the IVD was found to be very effective: All 30 men had either no sperm in their semen or levels that were too low to cause a pregnancy (www.NewMaleContraception.org).

A new contraceptive drug investigated in rats has been shown to stop the development of sperm (Nat Med. 2006; 12:1323-1328). Tests on rats have demonstrated that blocking connections to cells that nurture the development of sperm renders the animals infertile. The study used the recently developed molecule Adjudin to remove the developing sperm from the Sertoli cells. Previous studies have shown Adjudin to be toxic at higher doses, but this study used a novel approach that linked the molecule to a recombinant follicle-stimulating hormone mutant, which served as the “carrier” that delivered the Adjudin, allowing much lower doses to be used. Developing sperm cells “fell off” before they were mature, causing a temporary loss of fertility. Studies in humans are now needed.