The University of Edinburgh is part of a groundbreaking trial, alongside nine other global sites including the United States, Sweden, Kenya, and Chile, testing a male contraceptive gel. The enrolment target is 450 couples worldwide with a staggered start – the University of Edinburgh is hoping to have completed enrolment by the end of March. EuSci had the pleasure of speaking to Edinburgh trial leader Dr John Reynolds-Wright.
The gel in question is a is a combination of testosterone (the male sex hormone) and Nesterone (synthetic progesterone, a hormone involved in sperm production amongst a plethora of other functions) and works by ‘turning off’ the part of the brain that instructs the testicles to make sperm.
“The purpose of the current study is to determine the efficacy of the male contraceptive gel but also to develop a better understanding of its side effect profile. We do not expect many side effects with the gel and those that have been found in earlier studies have been mild,” Dr Reynolds-Wright explained.
Dosing will be controlled accurately by dispenser pumps, and researchers will measure the contraceptive efficiency by assessing sperm counts, blood hormone levels, and monitoring pregnancy in the female partners. “From previous studies, we believe that the risk of pregnancy is small but currently unknown. All of the options are available to the couples if they become pregnant on this trial as if they were not on the trial – they can continue with the pregnancy or choose not to. We are asking that we can follow up any couples that become pregnant and to find the outcome of the pregnancy”
‘Acceptable’ side effects were […] lower in newer male trials than in female contraceptive trials several decades ago.
Importantly, this new formulation will ensure there is enough testosterone in the male body to function from the amount that is absorbed in the gel. This is a key factor as there have been multiple attempts at oral male contraception which encountered several issues – one of the common problems these methods was how frequently they had to be dosed due to break down of testosterone, making them impractical. Another trial using injectable contraceptives for men was discontinued in 2016 due to several side effects, including acne, mood swings, and loss of libido.
These adverse effects are similar to what women have been encountering for decades using the contraceptive pill. When inquiring why these side effects were accepted for women but not men, Dr Reynolds-Wright explained that “current male studies are conducted many years after the female contraceptive studies.” ‘Acceptable’ side effects were, therefore, lower in newer male trials than in female contraceptive trials several decades ago.
“There is already evidence from studies […] that there are men who would be keen to use a contraceptive and that their female partners would be happy to rely on this as their method.”
“There also has to be considered that for contraception, women are using it to prevent a condition in themselves (i.e. pregnancy) whereas in male contraception, men are using it to prevent a condition in someone else and so it could be argued that there may be a need for lower side effect rates. It is worth noting that in the injectable trial, despite being stopped for the frequency of side effects, the participants were still keen to use the injection even when experiencing side effects as they valued its contraceptive properties.”
Finally, I was curious if there needed to be a paradigm shift: contraception is so far largely a female task. However, Dr Reynolds-Wright has experienced a different side, “I think that there are already a significant proportion of men who would consider using a male contraceptive and I also think that we will find even more men who would be interested in using it once it has been brought to market. There is already evidence from studies conducted in Edinburgh, Cape Town, Shanghai and Hong Kong, that there are men who would be keen to use a contraceptive and that their female partners would be happy to rely on this as their method.”
The topic of contraception remains interesting despite being an age-old issue, and I am certain women all over the globe will welcome the active male contribution to it.
Want to participate?
The trial leaders in Edinburgh are still looking for healthy couples who have been in a relationship for at least 1 year and would be interested in taking part for up to 2 years in the study. Male partners must be aged between 18 and 50 and female partners aged between 18 and 34 at the time of enrolment. The study is conducted from the Simpson’s Centre for Reproductive Health at the New Royal Infirmary of Edinburgh. If you are interested, please contact them on 0131 242 2669.
This post was written by Chiara Herzog and edited by Karolina Zieba.
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