A multicenter phase IIb study of a novel combination of intramuscular androgen (testosterone decanoate) and oral progestogen (etonogestrel) for male hormonal contraception.

The effect of a novel combination of oral etonogestrel (ENG) and im testosterone decanoate (TD) on suppression of gonadotropins and spermatogenesis as a potential lead for male contraception was investigated. Healthy male volunteers were randomized into two groups receiving 300 microg ENG daily and 400 mg TD every 4 (n = 55) or 6 (n = 57) wk for 48 wk. At wk 48, all men except one in the 6-wk group suppressed sperm concentration to less than 1 million/ml.