When Are We Going to Have a Male Pill?
This recurrent question may be closer to being answered...and it may be sooner rather than later. In one of the most exciting breakthroughs reported at the XVI World Congress of the International Federation of Gynecology and Obstetrics, David Kinniburgh of the University of Edinburgh, Scotland, described preliminary, yet promising, findings from a study of a male contraceptive. He noted that investigators have traditionally explored 3 general approaches to male contraception: steroid feedback at the hypothalamus/pituitary level (used here), suppression of sperm production by luteinizing hormone/follicle-stimulating hormone receptor antagonists, and post-testis contraception (focusing on the epididymis). One of the stubborn problems with male contraception has been dissociating sperm production from testosterone production. Steroids that shut down sperm production do the same for testosterone production, necessitating "add-back" therapy.
Dr. Kinniburgh described a randomized controlled trial conducted at 2 disparate sites: Edinburgh and Shanghai. The investigators randomized 66 men to receive desogestrel either 150 mcg or 300 mcg orally on a daily basis for 24 weeks. In addition, each participant received a testosterone subdermal implant, 400 mg, every 12 weeks for androgen replacement therapy. Nine men withdrew from the study, 4 in Edinburgh and 5 in Shanghai, but none because of serious adverse events.
Both doses of desogestrel profoundly suppressed sperm production. However, only the 300-mg daily dose led to total azospermia in all the Edinburgh and Shanghai participants. Hormone assays confirmed physiologic androgen levels resulting from the testosterone implants. Kinniburgh concluded that this approach to male contraception seemed promising: profound sperm suppression, maintenance of normal androgen levels, and no serious adverse events. Sperm concentrations returned to pretreatment values in all men after discontinuation of the regimen.
Several other hormonal regimens have been tested for male contraception. These include testosterone enanthate, levonorgestrel butanoate/testosterone buciclate, 7-alpha-19-methyl nortestosterone (MENT), and levonorgestrel/testosterone enanthate.  Male contraception with desogestrel, combined with replacement testosterone by implant, has promise. Several caveats deserve mention, however. First, this regimen is inherently more complex than oral contraception for women. Women take either an oral contraceptive or an implant (eg, subdermal levonorgestrel or 3-ketodesogestrel [etonogestrel] rods), but not both. In general, the more complex a regimen, the poorer the compliance and acceptability. In a later press conference, Dr. Kinniburgh noted that a pharmaceutical company will be continuing this development and will shift to a monthly injection of testosterone instead of the implant. Male contraceptives that suppress spermatogenesis have another drawback: the delay between initiation and infertility, generally about 2-3 months. This necessitates use of alternative contraception early on.
Both compliance and acceptability of hormonal contraception among men are unknown. Similarly, would women be willing to trust men to be compliant with pill-taking when the women suffer the consequences of imperfect compliance? A recent survey conducted among women in family planning clinics in Scotland, China, and South Africa suggested that a large proportion of women would be comfortable relying on a male pill. Given the reticence of some men to undergo vasectomy because of fears about potential effects on their virility, the notion of needing replacement testosterone therapy may deter men from this hormonal approach.
Medscape Ob/Gyn. 2000;5(2) © 2000 Medscape
Cite this: Updates in Contraception From The XVI World Congress of the International Federation of Gynecology and Obstetrics - Medscape - Sep 20, 2000.