Research on male contraception is slow, but advancing. Here are three main tracks that will be presented on Monday at a congress organized in Paris under the auspices of the Academy of Medicine.
However, this work is still at an early stage. Clinical trials are rare in this area, given both scientific and economic difficulties, and the pharmaceutical industry shows little interest in the topic.
A gel on the shoulder
This is the most advanced line of research, even though the studies are far from being able to foresee rapid commercialization.
This is a gel to apply to his shoulder every day. It contains both a female hormone called progestin to block the formation of spermatozoa and testosterone to counteract the effects of the former on libido or hair growth.
Why go through the skin and not orally like the female pills? This is because testosterone is better absorbed through this channel. Absorbed in a pill, the effects disappear even before the end of the day. They last longer with a gel.
The studies, conducted primarily in the United States, are currently in Phase 2, the most advanced for ongoing work on a male contraceptive. Performed with about 200 pairs, they should give a first idea of the effectiveness of this method, the safety and reversibility of which have already been sufficiently proven.
According to endocrinologist Régine Sitruk-Ware, who participates in these trials and also organizes the symposium in Paris, the first results are good enough to accelerate progress.
“This product seems to be very effective and very well accepted”, she reports to AFP. The researchers are already going to ask US health authorities to approve the next phase, which will make it possible to really guarantee the effectiveness of the product by testing it on a much larger number of people.
However, we are far from being on the market yet. “In principle you could say in five years, but that is the optimistic view, there are always unforeseen hurdles to overcome during development”warns Mrs. Sitruk-Ware.
Pills remain under study
Because of the difficulties in taking testosterone orally, a male pill is difficult to conceive. But researchers continue to follow this path and have seen encouraging early results on humans in recent years.
To achieve this, it was necessary to give up a concept: a concept that, like the gel described above, consists in combining two hormones, a progestin associated with testosterone.
Instead, researchers work from a single hormone. This simultaneously has the two desired effects: progestin, by limiting the production of spermatozoa, and androgen, by replacing the role of testosterone.
In fact, we know of two synthetic hormones that can play this dual role. Research is therefore underway on pills made from each of them.
In recent years, this research has gone through a first phase, which guarantees that these pills are well tolerated, ie without serious and systematic side effects.
We also know that they do not appear to have an irreversible effect on fertility. It remains to be assessed whether they are sufficiently effective.
“Unfortunately, testing and results are taking a long time due to Covid”explained to AFP researcher Stephanie Page who is working on one of these pills.
A sperm blocker
This is an even less advanced track than the previous two, but for which the first human trials should begin by the end of the year to first ensure it is well tolerated with no apparent side effects.
The principle is to inject a gel that blocks the sperm during ejaculation, without preventing it. The promoters of this method, developed by the American startup Contraline, promise years of rest after the injection.
This operation is similar to a vasectomy, although unlike this, the designers ensure that the effect of the gel is systematically reversible.
The idea is not new either. A similar concept, Risug says, has been studied in India for several years. The researchers had reported positive results in 2019, but have not provided any news since.