Male Contraceptive Implant Gets Trial Run

July 11 -- It's a birth-control option men can't forget to take.

Dutch pharmaceutical company Organon has begun clinical trials into what it hopes will be long-term, reliable, safe, and reversible hormonal contraception for men.

What makes this contraceptive option different is that instead of a pill, tiny rods would be implanted under the skin of a patient's arm that would deliver etonogestrel, a form of progestogen commonly found in the female birth control pill, to block sperm production.

Because this form of hormonal contraception essentially would shut down testosterone and sperm production from the testicles, replacement therapy will be given to men participating in the trials. Participants will have to get testosterone replacement therapy injections every four to six weeks over the course of a year in order to help maintain their sex drive, as well as their male characteristics.

About 120 men between the ages of 18 and 45 from Europe and the United States will be used in the yearlong study. The results of the study are expected to come out sometime in 2002, and if all goes well, the product could be available by prescription as early as 2005.

Results from a smaller study by the pharmaceutical company last year using a similar method showed a completely reversible blockage of sperm production without major side effects, Organon said. The most notable side effect of the contraceptive includes weight gain — similar to what women experience while on the pill.

"The results found in studies performed until now have been so encouraging, showing completely reversible blockage of sperm production without major side effects, that we can't wait to move forward and start with this next study," said Dr. Fred Wu from the Manchester Royal Infirmary in a statement.

A Promising Clinical Lead

To date, the most reliable form of male contraception has been the condom, which has a failure rate of about 14 percent under typical conditions, according to the Food and Drug Administration. The failure rate of the female birth control pill is less than 1 percent.