Oct. 8, 2003 -- New research from Australia offers proof that hormone-based contraceptives can work in men as well as women, but that doesn't mean a male birth control pill will be available anytime soon.
Although two drug manufacturers are currently collaborating on the development of a male pill, longtime contraception researcher David J. Handelsman, PhD, says he is not convinced that commercially available hormonal contraception will ever be a reality for men.
"There is absolutely no biological reason why hormonal contraception for men couldn't have been introduced four decades ago when oral contraceptives became available for women," Handelsman tells WebMD. "It has taken four decades to get this far because the pharmaceutical companies did not believe men would be interested despite their own market research, which told them that was nonsense."
In their newly reported trial, Handelsman and colleagues found the combination of the male sex hormone testosterone and steroid-derived hormones known as progestins to be 100% effective in preventing pregnancies in 55 couples followed for one year. The combination had been shown to prevent sperm production in previous studies, but theirs was the first to show that it is an effective male contraceptive.
Just as birth control pills trick the female body into thinking that there is an excess of certain hormones, thereby inhibiting pregnancy, the male hormone combination tricks the male body into thinking that it has produced enough testosterone, thereby inhibiting sperm production.
According to Handelsman, the combination protocol was devised after trials of testosterone alone found the single-hormone approach to be an unreliable contraceptive method in up to a third of men. The testosterone trials also involved weekly injections, which the researcher says is simply not practical.
The men in the study were given progestin injections every three months, and they received testosterone by surgical implants every four months. All the men were followed for a year after their sperm counts had fallen to zero. All were in stable relationships, and no pregnancies occurred during the 12-month follow up period, even though no other birth control methods were used.
Sperm counts returned to their pre-trial levels in all of the men within six to 12 months after the last treatment.
"Obviously a study of 55 men only proves the principle," Handelsman says. "There were no pregnancies in our group, but it will take studies involving hundreds of men to prove efficacy. And proof of safety will require studies involving thousands of men."
A Male Pill?
In a joint research effort, pharmaceutical companies Schering AG and Organon International are focusing on the development of a male hormonal pill, which they say could be on the market within six years.
Handelsman says a male birth control pill would undoubtedly prove less reliable than injections or implants, and he remains unconvinced that any drug company will follow through with a hormonal contraceptive for men of any kind, unless there is a public outcry calling for one.
"Studies have shown that men all over the world want this, but I'm guessing that there are people within all of these companies who don't believe there is a market," he says. "And if the first (commercial) trials fail, that may be the end of the commitment."
Doug Colvard, a spokesman for the Virginia-based contraceptive research group CONRAD, which funded the Australian research, tells WebMD that the Australian experiment is one of many trials examining different hormonal contraceptive methods for men.
"There are many investigators working on this, and it is becoming increasingly evidence that this approach can reliably suppress fertility without affecting male sexual function," he says.