'Major milestone' hit for new male contraceptive

Trials have shown that a new male contraception can last for at least two years

A male contraceptive that prevents sperm from leaving the body is effective for at least two years, results from trials suggest.

The implantable, non-hormonal male contraceptive – known as ADAM – is designed to prevent sperm from mixing with semen and breaks down in the body after a set period of time.

The water-soluble hydrogel is implanted in the sperm ducts and is a reversible alternative to condoms and vasectomies, according to Contraline, the US-based company behind the innovation.

Findings from its phase one clinical trial have been released by Contraline, which show that ADAM could successfully block the release of sperm for 24 months. Two participants have so far reached this time point in the trial, and no sperm has been detected in their semen. The company added that no serious side effects have been recorded.

Dr Alexander Pastuszak, Contraline’s chief medical officer, said: "Our goal was to create a male contraceptive option lasting two years, responding directly to consumer needs.

"These findings confirm that ADAM, our novel water-soluble hydrogel, can achieve the intended lifespan. We remain optimistic about its safety, efficacy, and reversibility, and its potential to give men and couples greater reproductive control."

The clinical trial includes 25 participants who were enrolled at different points in time. More results are expected to follow, The Guardian reports.

Contraline’s founder and chief executive, Kevin Eisenfrats, told the Guardian: "This is really exciting because our goal since day one has been to create a two-year-long male contraceptive – that is what the demand is for: a two-year-long, temporary or reversible male birth control. And we have the first data to show that that’s possible."

The results of the study do not include data on the reversibility of the implant, but the company says the hydrogel breaks down in the body and restores fertility.

He added: "The way to think about this is sort of like the IUD [intrauterine device] for men."

Non-hormonal intrauterine devices (IUDs) for women include the copper coil, which can last for up to 10 years and fertility levels return to previous levels right after removal. Common hormonal methods of contraception for women include the pill, the hormonal coil, implant, injection, patch and vaginal ring.

Eisenfrats said that men could decide whether to get another implant after a two-year period. The team is also working on a procedure to enable "on-demand reversal".

However, there are some concerns over how reversible the gel is. Professor Richard Anderson, an expert in hormonal male contraception at the University of Edinburgh, warned that it is not yet clear how long a single implant lasts and whether it can be removed.

That said, Prof Anderson said: "It’s impressive that this looks like something that does actually work, which is great.

"We’ve now got hormonal and non-hormonal methods in advanced clinical development, which is potentially a much better position than we’ve been in previously in terms of actually getting something on the market for men to really use."

The company has announced it has received approval to initiate its phase two clinical trial in Australia later in 2025, which Contraline described as a "major milestone in the development of long-lasting, reversible male contraceptives, paving the way for accelerated progress and global momentum toward much-needed innovation in reproductive health."

Results from the Adam trial have not yet been published or peer reviewed. Findings will be presented at the American Urological Association meeting on April 26.