Hormone-free male contraceptives are 99% effective in preclinical trials and are expected to enter human trials by the end of the year

On Wednesday, a team of scientists said they had developed a male oral contraceptive that was 99 percent effective in mice with no apparent side effects, and is expected to enter human trials by the end of this year

The findings, to be presented at the Spring Meeting of the American Chemical Society, mark a key step forward in expanding contraceptive choices and accountability for men

Md Abdullah Al Noman, a graduate student at the University of Minnesota who will lead the study, told AFP that researchers have been interested in male contraceptives since they were first approved for women in the 1960s

"Multiple studies have shown that men are willing to share the responsibility for birth control with their partners," he said, but so far there have only been two effective options: condoms or vasectomy

Vasectomy reversal surgery is expensive and not always successful

Female birth control pills use hormones to disrupt the menstrual cycle, while historical efforts to develop male birth control pills have focused on the male hormone testosterone

The problem with this approach, however, is that it can lead to side effects such as weight gain, depression and elevated levels of LDL (a type of cholesterol), which increases the risk of heart disease

Female birth control pills also have side effects, including the risk of blood clots — but since women can become pregnant without birth control, the risk is calculated differently

Hormone-Free Contraceptives

To develop a non-hormonal drug, Noman, who works in Professor Gunda Georg's lab, targeted a protein called retinoic acid receptor (RAR) alpha

In the body, vitamin A is converted into different forms, including retinoic acid, which plays an important role in cell growth, sperm formation, and embryonic development

Retinoic acid needs to interact with RAR-alpha for these functions, and laboratory experiments have shown that mice without the RAR-alpha gene are sterile

In their work, Noman and Georg developed a compound that blocks the effects of RAR-alpha

"If we know what a keyhole looks like, then we can make a better key -- that's where computational modeling comes in," Noman said

Their chemical, YCT529, was also designed to interact with RAR-alpha, but not the other two related receptors, RAR-beta and RAR-gamma, to minimize potential side effects

Will be listed in 5 years

When administered orally to male mice for 4 weeks, YCT529 greatly reduced sperm count and effectively prevented 99 percent of pregnancies in mating assays

The researchers monitored weight, appetite and overall activity and found no apparent adverse effects, although the mice certainly couldn't report side effects like headaches or mood changes
.

Four to six weeks after stopping the drug, the mice were able to produce male offspring again
.

Georg said the team, which is funded by the National Institutes of Health and the Male Contraception Initiative, is working with a company called YourChoice Therapeutics and plans to launch a 2022 or 2022 release date.
Human trials begin in the fourth quarter
.

"I'm optimistic this will move forward quickly,
" she said, envisioning a timetable that could go public in five years or less
.

"No one can guarantee that it will work .
.
.
but I would be really surprised if we didn't see this effect in humans," she added
.

An ongoing question about the future of male contraceptives is whether women will trust men to use them
.

But surveys show that most women actually have confidence in their partners, and a significant number of men say they are open to drug treatment
.

"Male contraceptives will be part of mixed contraceptive methods, offering new options for both men and women to provide contraceptives in any way they see fit
.
"