Human trials start this year, male contraceptives are really coming

Recently, a Japanese drama that many people are curious about will be broadcast in April 2022 – "Kentaro Hiyama's Pregnancy" starring Ueno Shuri and Saito Kou. The story is set in a world where men can get pregnant and have children. After advertising elite Kentaro Hiyama (played by Ko Saito) finds out that he is pregnant, he and his partner Aki Seto (played by Ueno Kiri) begin to face the challenges brought about by pregnancy and childbirth. many questions.

Picture from: Douban

It's really curious what kind of story this new show will show, but for now it's just a bold idea for a man to get pregnant and have a baby. But when it comes to fertility, a male-related thing is about to become a reality – the male birth control pill may really be coming.

Researchers at the University of Minnesota have developed a compound called YCT529, a non-hormonal male contraceptive that appears to have no side effects, and early human trials of the drug are expected to begin by the end of this year.

▲ Picture from: Getty Images

The researchers say the non-hormonal male contraceptive works by targeting vitamin A in the body. Research has shown that vitamin A is important for mammalian fertility. Moderate amounts of vitamin A can improve fertility and also play an important role in sperm quality.

After a long search, they discovered an experimental compound that blocks a protein. This protein is responsible for binding to a type of vitamin A (retinoic acid) in our cells called retinoic acid receptor alpha (RAR-alpha).

▲ Image from: shutterstock

It is by selective blockade of this protein that the researchers hope to induce durable but reversible birth control while causing little off-target effects elsewhere (ie, not interacting with targets outside of the drug's design, that is, producing no off-target effects). side effect).

So far, YCT529 has been working as expected. New data presented by the research team at the American Chemical Society (ACS) Spring Meeting not long ago showed that male mice treated with the drug for 4 weeks continued to see a sharp drop in sperm counts. They estimated that YCT529 It is 99% effective in preventing pregnancy with no apparent side effects.

▲ Picture from: ACS

Fertility returned about four to six weeks after the male mice stopped taking the drug. Their other studies in animals also suggest that inhibiting RAR-alpha should be safe and effective in inducing "transient male sterility."

Md Abdullah Al Noman, who was part of the research team, said contraceptives are prone to side effects because men don't have to suffer the consequences of pregnancy, which is why attempts have been made to develop non-hormonal contraceptives to avoid hormonal side effects.

▲ Picture from: Unsplash

The researchers also said that there are other male birth control methods in clinical trials, but achieving the goal will not be easy. Most approaches employ hormones that work against testosterone, which may have unwanted side effects such as increased cholesterol or decreased libido, and YCT529 eliminates those concerns.

At present, the contraceptive measures for men seem to be mainly the use of condoms or ligation, while the drug-based contraception is more aimed at women, and the resulting side effects are mostly borne by women.

▲ Picture from: Unsplash

In fact, some people have been researching male contraceptives. For example, WIN-18446, which has been researched by scientists in the United States, has an obvious and reversible inhibitory effect on sperm, but it was later found that the user will have severe side effects after drinking alcohol; the effect of gossypol is also obvious.

There is also the "magnetic control contraceptive" technology researched by Nantong University; the tripterygium lactone with contraceptive effect extracted from "Tripterygium wilfordii" by Chinese scholars…

▲ Tripterygium, picture from:

There are also some promising male contraceptives, such as the RISUG injectable contraceptive in India, which has a success rate of 97.3%. It is said that there are no side effects, and the contraceptive period of one injection can be valid for up to 13 years. Clinical trials have been completed and are currently waiting. Approval; NES/T gel in clinical trials in the U.S.…

▲ RISUG, picture from: The Flow

With so many male contraceptives under study, why hasn't one been successfully marketed yet?

Many male contraceptives have more or less side effects, and the success rate of male contraceptives is difficult to guarantee, because female contraception only needs to consider the monthly release of a fixed number of eggs (usually one per month), but the number of sperm is in the thousands Countless, the effect is difficult to control. For various reasons, drug R&D companies have been underdeveloped in this regard due to revenue considerations.

In terms of effects and side effects, the performance of YCT529 studied at the University of Minnesota is worth looking forward to, and it has now been licensed to YourChoice Therapeutics for further development. Although there is still a long way to go before it can be officially commercialized, it is also a hope for male contraceptives, so that both men and women can have more choices to take responsibility for contraception.

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