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Injectable combination hormonal contraceptive effective in men
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Men assigned norethisterone enanthate with testosterone undecanoate for up to 26 weeks effectively achieved suppression of spermatogenesis, and the effect was successfully reversed in most men, international study data show.
“The study found it is possible to have a hormonal contraceptive for men that reduces the risk of unplanned pregnancies in the partners of men who use it,” Mario Philip Reyes Festin, MD, of WHO in Geneva, said in a press release. “Our findings confirmed the efficacy of this contraceptive method previously seen in small studies.”
Festin and colleagues evaluated 320 healthy men (median age, 32 years) and their healthy female partners, all without known fertility problems, to determine the effect of intramuscular injections of 200 mg norethisterone enanthate plus 1,000 mg testosterone undecanoate, administered every 8 weeks, on suppression of spermatogenesis and contraceptive protection.
Ejaculate analysis was used to measure suppression of spermatogenesis, and pregnancy rate was used to measure contraceptive protection.
Overall, 274 participants achieved suppressed sperm concentrations of 1 million/mL or less by the end of 24 weeks; there was a 95.9 per 100 continuing-user rate, according to the researchers.
During the 56-week efficacy phase, four pregnancies occurred among partners of 266 participants; there was a 1.57 per 100 continuing-user rate.
Overall, participants achieved recovery of spermatogenesis for a rate of 94.8 per 100 continuing users who transitioned to the efficacy phase.
Acne, injection-site pain, increased libido and mood disorders were the most common adverse events, the researchers wrote.
Recruitment and hormone injections were terminated early to follow recommendations of an external safety review committee. According to a research project review panel, the risks to study participants outweighed the benefits; the adverse events of mood changes, depression, pain at the injection site and increased libido were of most concern.
“More research is needed to advance this concept to the point that it can be made widely available to men as a method of contraception,” Festin said in the release. “Although the injections were effective in reducing the rate of pregnancy, the combination of hormones needs to be studied more to consider a good balance between efficacy and safety.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.
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