The Population Council is pioneering work on Adjudin, a potential new, safe, effective, and reversible male contraceptive.
Men’s contraceptive options are limited to the male condom and vasectomy. Neither method is ideal for most couples: Vasectomy is irreversible, while the condom has a relatively high failure rate compared to other family planning methods available to women. As a result, the burden of preventing unintended pregnancies falls largely on women.
The Population Council is working to develop safe, reliable, reversible male contraceptives. Adjudin is a promising nonhormonal method that causes reversible infertility by disrupting spermatogenesis.
Adjudin was derived from the anti-cancer drug lonidamine. Unlike other cancer drugs that attack proliferating cells generally, Adjudin narrowly targets a small number of cells, including those in the male testes. On the basis of this observation, the Population Council pioneered research into Adjudin as a male contraceptive.
Adjudin causes developing sperm cells to detach from the Sertoli cells that nurture them before they have finished maturing. The prematurely detached cells die, causing temporary infertility. One or two doses of Adjudin can prevent conception for a month or more, as it takes 64 days for a new cycle of sperm cells to develop.
Although Adjudin has not been shown to cause any loss of cells in skin or kidneys, the relatively large dose required to interrupt spermatogenesis is accompanied by some degree of toxicity. The margin between safety and efficacy is narrow. As a result, Council researchers are working to develop alternative formulations that are better absorbed, thus delivering higher potency with a smaller, less toxic dose.
The Council has developed an Adjudin formulation that can be efficacious at one-tenth the original dosage, thus significantly reducing the risk of toxicity. In animal models, Adjudin has successfully caused male infertility with no chemical or structural damage, so that full fertility is restored after the drug is discontinued.
In addition to its contraceptive benefits, Adjudin also has mild anti-cancer and anti-neurodegenerative effects, which could increase its acceptability and improve adherence should it be introduced as a contraceptive option.
Laboratory research on Adjudin continues, with the goal of entering clinical trials within the next five years.