SYDNEY, 8 October 2003 — A new hormone-based contraceptive treatment which stops men from producing sperm has prevented pregnancy among 55 couples during a 12-month test, researchers said yesterday.
The study, a US government-funded program sponsored by Virginia-based family planning organization CONRAD, was able to successfully and reversibly turn off sperm production in the men who took part, said Rob McLachlan, director of clinical research at Prince Henry’s Institute of Medical Research in Sydney, Australia.
Australian researchers pitched the study and won financial backing from CONRAD, which often funds medical studies outside of the United States and works closely with the World Health Organization.
“This is the first time the combination of long-acting testosterone and a progestin have been used in an effectiveness study, this is the first to be reported in the world,” McLachlan said in a telephone interview. “We’re very pleased and excited the results are so positive.”
It was an 18-month commitment by the 55 couples involved, McLachlan explained.
The trial was conducted in two phases. The first, over three to six months, involved taking testosterone and progestin to turn off sperm production. Then when the sperm count was zero or close to zero, the 12-month trial period began.
“What was unusual was the fact that this was an effectiveness study,” McLachlan said. “Once the sperm was suppressed the couples used this as their (contraceptive) method. Other studies only monitor how far the sperm count falls.”
Over the 12 months of the trial, the men continually took implants of testosterone and injections of progestin, a reproductive hormone. The implants require minor surgery to put them under the skin, McLachlan said.