Although it's been talked about for years, researchers now say that a male hormonal contraceptive really could be just around the corner. The prediction follows research findings in The Lancet confirming the reversibility of a male contraceptive undergoing clinical trials in Europe and China. The trial found that several months after the contraceptive was stopped, sperm levels returned to normal in all of the men. The new contraceptive works in a similar way to ovulation suppression in women using oral contraceptives. With the male (androgen) treatment, sperm production can be fully inhibited, or lowered to the point where fertilization is extremely unlikely. Currently, a large phase III study with an androgen treatment is being conducted in China and a large phase II study of androgen-progestagen treatment is running in Europe.
The reversibility findings were announced by Peter Liu, from the Los Angeles Biomedical Research Institute, who analyzed data from individual participants where sperm output was monitored every month until recovery. The key measurement was the time for the sperm concentration to recover to a threshold of 20 million/mL, an indicator of fertility.
Liu said the average time for sperm recovery to 20 million/mL was 3 - 4 months. Various factors such as older age, Asian origin, shorter treatment duration, and higher sperm concentrations at baseline affected the time to recovery, but spermatogenesis recovered to fertile levels in all the men.
"Our data provide strong assurance that the previously described efficacy of hormonal male contraceptives is coupled with highly predictable recovery to semen characteristics that are compatible with fertility. These findings thereby increase the promise of new contraceptive drugs allowing men to share more fairly the satisfaction and burden of family planning," concluded Liu.
Based on material from the Los Angeles Biomedical Research Institute
