There has been a lot of chatter about male contraception, but this week researchers have officially kick-started a clinical trial of a male contraceptive gel.
Until now common forms of male contraception are either short-term, such as condoms, or long-term, a vasectomy.
But condoms are actually only 85% effective when real life use is taken into consideration, and vasectomies, though effective, are often not reversible.
So scientists have been busy trying to devise another form of male contraception in the form of a gel.
“Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms,” said study investigator Diana Blithe, Ph.D., chief of NICHD’s Contraceptive Development Program said in a statement announcing the trial last year.
“A safe, highly effective and reversible method of male contraception would fill an important public health need.”
The gel formulation, includes the progestin compound segesterone acetate (brand name Nestorone), in combination with testosterone. It is applied to the back and shoulders and absorbed through the skin.
It works because the progestin blocks natural testosterone production in the testes, reducing sperm production to low or nonexistent levels.
The replacement testosterone maintains normal sex drive and other functions that are dependent on adequate levels of the hormone.
The trial, funded by the National Institute of Child Health and Human Development (NICHD), is set to enroll approximately 420 couples, from nine different study sites in seven countries scattered across the world, including Chile, England, and Sweden. But the first batch of volunteers will come from the US.
Male volunteers will use the gel daily for four to 12 weeks to determine whether they tolerate the formulation and to ensure they do not experience unacceptable side effects.
If sperm levels have not adequately declined, they will continue to use the formulation for up to 16 weeks. Once their sperm levels have declined to a threshold sufficient for contraception, they will enter the efficacy phase, which will evaluate the ability of the formulation to prevent pregnancy.
This phase will last for 52 weeks, and the couple will rely on the male partner’s application of the gel as the sole method of contraception.
During the trial scientists also plan on keeping a close eye on participants and their partners via questionnaires, which adds another layer to the research.
“This is something quite different from what we used to do. When you look at the studies of female contraceptives, they never assess the guys,” Christina Wang, a researcher at the Los Angeles Biomedical Research Institute and principal investigator of the trial told Gizmodo.
“We want to make sure that the couple coming in, the couple that’s using this contraceptive, is satisfied with using this method.”
So what happens if the trial is successful?
Well even if everything does go to plan it will be quite some years before we may see the gel stocked in Boots.
According to Gizmodo, the trial will fully wrap up by 2022. But it won’t end there as because it’s only a phase 2b clinical trial, further studies will be required before the gel will be given official approval by the Food and Drug Administration (FDA).
It isn’t the first time scientists have attempted to bring a male contraception to the market.
While trials of a new male pill, which works by lowering levels of testosterone and two hormones required for sperm production, have been showing promise, previous attempts to create a male pill, have resulted in side effects such as liver damage or low sex drive.
But earlier this year a team of Chinese researchers revealed they had been trialling a ‘medium-term’ reversible form of male contraception in rats.
Commenting on the findings, published in the journal ACS Nano, study leader Dr Xiaolei Wang, of Nanchang University, said: “The injected materials kept the rats from impregnating females for more than two months.”
However, when the researchers shone a near-infrared lamp on the rats for a few minutes, the layers mixed and dissolved, allowing the animals to produce offspring.
Dr Wang said the pilot experiment was “promising” but more research is needed to verify the safety of the materials uses.