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| |  DG DISPATCH - ENDO 99: Male Contraceptive Pill/Patch Can Stop Sperm Production By Cameron Johnston Special to DG News SAN DIEGO, CA -- June 16, 1999 -- A transdermal testosterone patch used in combination with oral desogestrel has been shown to induce azoospermia -- the complete cessation of sperm production -- in a small group of men. This drug combination could ultimately serve as a male form of oral birth control, researchers reported at the Endo ‘99 meeting. The pill/patch combination was capable of eliminating sperm production entirely in some men, while reducing sperm density from as high as 200 million sperms per millilitre to less than one million sperms per millilitre. However, only total azoospermia in the entire cohort of test subjects could be considered acceptable, explained Dr. Frederick Wu, senior lecturer in medicine at Manchester University. The combination regime involved men taking either 75, 150 or 300 mcg (micrograms) per day of desogestrel while, at the same time, wearing two 2.5 mg testosterone patches (SmithKline Beecham’s Andropatch) per day for a period of 24 weeks. Complete azoospermia was achieved in 66 percent of the 300 mcg desogestrel group and in 60 percent of the 150 mcg group. Azoospermia was not achieved in the 75 mcg group. Dr. Wu explained that desogestrel, which is also used in female contraceptives, stops the production of testosterone in the testis, while the testosterone patch provides the needed testosterone to the rest of the body. Testosterone concentrations in the testis are more than 100 times greater than testosterone concentrations in the bloodstream. "We’re using the same principal as female contraceptives," he said in an interview with Doctor’s Guide. “We block the signalling in the brain that tells the testis to produce testosterone. The way to remove the testosterone in the testis is to remove the gonadotropins, so the testis no longer produce testosterone, either for the testis and spermatogenesis or for other circulating targets. But we put back testosterone with the patch so the rest of the body does not become androgen deficient.” The elimination of all testosterone would cause the men to lose facial and pubic hair and could lead to the development of breasts. "We were adding back the testosterone, but not in sufficient quantities to lead to spermatogenesis," he explained. Dr. Wu said that while the concept is valid, putting the results into practice in the form of a commercially-available male contraceptive may still be some years away. One problem is that azoospermia was achieved in less than two-thirds of the men, meaning a lot of men would still be capable of fathering children. Also, even for those who achieved azoospermia, there were still periods during the 24-week study when the men were producing some sperm -- although in very small amounts. "It’s very difficult to get everybody azoospermic. There is still this very stubborn 20 percent or so who go from 100 million sperms per ml to less than a million, but in terms of contraception, you only really need one sperm," he said. "We know that if we can achieve azoospermia, it can be effective, but the question now is what is the safest and easiest way of achieving this target and what is the best combination and delivery system to make it genuinely acceptable." Only rendering two-thirds of the men azoospermic, which was accomplished in this study is very far from ideal, he added.
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