Birth control pills for men have been developed in the US

American scientists have created the world's first birth control pills for men, and they've already been proven effective in mice.

Maria Zavialova

The birth control pills, developed by experts at Weill Cornell Medicine, have been designed to temporarily halt sperm and prevent pregnancy in preclinical trials. This means that a male contraceptive pill that can be taken on-demand is now a reality.

Dr. Jochen Buck and Dr. Lonny Levin, professors of pharmacology at Weill Cornell Medicine and co-senior authors of the study, believe that this development has the potential to be a “game changer” in the field of contraception.

Why male birth control pills weren’t introduced sooner

For men, the only choices are condoms and vasectomy. Most current efforts to develop new contraceptives for men impact sperm development. It means that contraception requires months of continuous pretreatment. Here, we provide proof-of-concept for an innovative strategy for on-demand contraception. So, a man would take a birth control pill shortly before sex, only as needed.

Co-senior authors Dr. Jochen Buck and Dr. Lonny Levin, professors of pharmacology at Weill Cornell Medicine

The development of male oral contraceptives has hit a roadblock, largely due to the heightened safety and side effect standards that they must meet, according to Dr. Levin. Men aren’t the ones carrying a child and all the risks attached. So, the industry has traditionally assumed that men would be less willing to tolerate potential side effects from contraceptives.

Historically, hormonal contraceptives with high efficacy rates have only been available to women, despite the accompanying side effects. However, scientists from Weill Cornell Medicine are shaking things up by asserting that they have created a product that is entirely side effect-free.

New birth control pills were invented accidentally

Buck and Levin’s journey to creating a male contraceptive was an unexpected one. The two were friends and colleagues, each with their own unique set of skills. It was during a challenge posed by Dr. Levin to isolate the elusive soluble adenylyl cyclase (sAC) protein that Dr. Buck became interested in the project. It took two years of dedicated work, but Drs. Buck and Levin successfully isolated sAC and decided to delve deeper into their research by merging their labs.

Their tireless efforts ultimately led them to discover that mice without the sAC protein were infertile. It opened the door to exploring its potential as a contraceptive. In 2018, their lab’s PhD student, Dr. Melanie Balbach, made an exciting breakthrough. She found that treating mice with an sAC inhibitor resulted in immobile sperm. With this discovery, the team felt confident that inhibiting sAC could be a safe and effective contraceptive option. Previous research had shown that males without the sAC gene were infertile but otherwise healthy.

Research results

Intriguingly, just one dose of the sAC inhibitor TDI-11861 is capable of rendering mouse sperm immobile for a staggering two and a half hours. And its effects persisting even after mating. Although some sperm start regaining their mobility after three hours, it takes a full 24 hours for nearly all sperm to regain normal movement.

Interestingly, male mice treated with TDI-11861 still exhibited normal mating behavior. Yet none of the 52 mating attempts with female mice resulted in pregnancy. In stark contrast, male mice given an inactive control substance successfully impregnated almost one-third of their mates.

Our inhibitor works within 30 minutes to an hour. Every other experimental hormonal or non-hormonal male contraceptive takes weeks to bring sperm count down or render them unable to fertilize eggs.

Dr. Melanie Balbach

Furthermore, Dr. Balbach pointed out that reversing the effects of other hormonal and non-hormonal male contraceptives currently in development can take several weeks. This is due to the fact that sAC inhibitors only last a few hours. It allows men to take them as needed and when needed. This newfound flexibility will empower men to make daily decisions about their fertility.

What’s next: making birth control pills fit for humans

Moving forward, the team plans to repeat their experiments using another preclinical model as a stepping stone towards human clinical trials. These trials will help test the effects of sAC inhibition on sperm motility in healthy men, according to Dr. Buck.

The team is already working on making sAC inhibitors better suited for use in humans.

Drs. Buck and Levin

Dr. Levin envisions a future where a man can walk into a pharmacy and confidently ask for a “man pill”.

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