The Kenyatta National Hospital(KNH) is currently carrying out clinical trials on male hormone contraceptives. Kenya is conducting these trials alongside Italy, Scotland, Sweden, United Kingdom and United States. The male contraceptive is currently on Phase 2 testing, meaning the doctors are checking for its safety and efficacy. Previous studies involving men in western countries were used to determine the effective dosage which also demonstrated that the related adverse effects of using the gel are unlikely. Therefore, the risks of participation in this study are expected to be minimal.

Usually, 40% of pregnancies in the world are unintended. While women hold nearly all the cards when it comes to family planning, men are limited to a few options namely: withdarawal, condoms, and vasectomy. Condoms (85% effective) suffer from inconsistent use, vasectomy (99% effective) requires surgery which is not reliably reversible, while withdrawal (78% effective) meaning that 22 out of 100 women who use it in a year will get pregnant. Therefore, an extra contraceptive method available to men is always welcome, especially when it offers novel features.

The male hormone contraceptive used in the clinical trial is Nestorone®/Testosterone Transdermal Gel for Male Contraception developed by Population Council in collaboration with NICHD. It is a gel containing Nestorone (a powerful progestin) and testesterone that is applied on the skin. This contraceptive is marketed as safe, reversible, affordable and can be self-delivered.

…40% of pregnancies in the world are unintended

The transdermal male hormonal conctraceptive regimen shows effective suppression of production of mature spermatozoa (spermatogeneisis). The gel in the current trial contains segesterone acetate (marketed as Nestrorone) and testosterone. Nestorone suppresses testosterone and other gonadotropin (such as FSH and LH) levels, which reduces sperm production as well and causes a man’s sperm count to drop below contraceptive levels (less than 1 million sperm per mililitre of semen). Low luteinizing hormone (LH) levels suppress testosterone production from the interstitial cells of the testes. While it is true that high levels of testosterone can suppress the release of the follicle-stimulating hormone (FSH) from the pituitary gland which will inhibit spermatozoa production, in this case, the testosterone levels in the gel are not high and just replenishes the testeterone supressed in equal physiological doses.

Why stop at 1 million sperm per mililitre of semen? Well, completely stopping spermatogenesis is not practical, so researchers identified a cut-off level that leads to effective sterility. In fertile men, ejaculate typically contains more than 15 million sperm per millilitre, and early trials suggested that reducing this to one million per millilitre would be sufficient.

Since Nestorone inhibits production of testosterone and pituitary hormones, extra testosterone must be added to maintain a normal hormonal balance, that’s why the gel contains testosterone. Nesterone is a powerful progestogen that remains active in circulation for twice as long as testosterone, which must be replaced daily, meaning that missing a dose wouldn’t necessarily increase spermatozoa production.

In the trials that have been conducted so far, 84% of men using this gel saw their sperm count fall below the threshold of one million sperm per millilitre within 28 days, with no serious adverse effects. However, some men take much longer to reach this 1 million sperm per mililitre threshold than others, some may take 2 to 4 weeks while others may take 16 to 20 weeks.

This contraceptive is marketed as safe, reversible, affordable and can be self-delivered.

Once a couple is enrolled, the man will start using the gel to suppress sperm production for up to 20 weeks, until his sperm count is consistently low enough to prevent pregnancy. During that period, the couple will still be allowed to use other forms of contraception. After that suppression phase, a 52-week efficacy phase will begin, where the couple uses the Nestorone and Testosterone (NES/T) gel as their only form of contraception.

Finally, during the recovery phase, estimated to be about 24 weeks, the man will stop using the gel to allow his sperm count to return to pre-suppression levels. During the entire trial, the man’s sperm count will be measured during monthly visits to ensure it stays below the fertility threshold. The pregnancy rate (based on the number of pregnancies that occur in the efficacy phase) and rate of compliance with gel usage will be assessed to both measure the gel’s efficacy and gauge the gel’s overall acceptance as a male contraceptive method. While the gel can, in principle, be applied topically anywhere on the body, the gel is to be applied to the shoulder or upper arms to reduce the risk of testosterone being transferred to others, especially women and children.

Side effects observed in previous studies included acne and dry skin, weight gain, and some mood changes, however, the doses of the components have since been modified to reduce chances of these side effects occuring. The gel is not yet available for sale in the market as the trials are still in progress.

The KNH is offering the male contraceptive gel free of charge to member who will qualify to participate in the 2 year long study. During the entire period of the study, the men using the gel will be closely followed up and monitored for any adverse events though such events are highly unlikely. Feel free to contact KNH trials on 0721144394 / 0701605711 and they will provide you with more information about the study.

Would you use Nestorone®/Testosterone Transdermal Gel once it hits the market?

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