A Multicenter Contraceptive Efficacy Study of Injectable Testosterone Undecanoate in Healthy Chinese Men

This report describes a Phase II, multicenter, contraceptive efficacy clinical trial using monthly injections of testosterone undecanoate (TU) alone at a dose of 500 mg in healthy Chinese men. Three hundred eight healthy men were recruited in six centers distributed throughout China. Volunteers underwent a control period with no treatment, then a 12-month treatment period including a 6-month suppression phase followed by a 6-month efficacy phase and a 12-month recovery period. During the suppression phase, an initial loading dose of 1000 mg TU, followed by 500 TU at monthly intervals were given until azoospermia or severe oligozoospermia was achieved, up to a maximum of six injections. During the efficacy phase, 500 mg TU were administered at monthly intervals for 6 months. Nine of 308 men did not achieve azoospermia or severe oligozoospermia (