WEDNESDAY, Feb. 15, 2023 (HealthDay News) — A man pops a bit of pill just before he expects to get frisky along with his girlfriend.
However the pill isn’t Viagra, as one might expect.
As an alternative, it’s an on-demand contraceptive that may prevent pregnancy even when taken just before sex.
Researchers think they’ve discovered a solution to create such a contraceptive pill for men, by inhibiting an enzyme that’s key to a sperm’s ability to swim.
Inhibiting this enzyme in lab mice using an experimental compound successfully prevented pregnancy, based on a brand new report published Feb. 14 within the journal Nature Communications.
“The effect began inside half-hour after dosing and the mice were completely infertile for the next two hours,” said co-senior researcher Lonny Levin, a professor of pharmacology at Weill Cornell Medicine in Recent York City.
“By the next day, the mice were completely normal. The compound didn’t adversely affect the mice in any way, and their sexual behavior and ejaculate were completely normal,” he added.
If proven to work in humans, such an approach “can be an amazing advancement for the sector,” said Christopher Lindsey, program officer on the U.S. National Institute for Child Health and Human Development, which helped fund the study.
“The advantage of that is that unlike a hormonal approach where you’d need to take that drug for days, weeks, sometimes months, this might work just like Viagra,” Lindsey said. “You’ll only need to take it possibly a short while back before engaging in sexual intercourse.”
Nearly half of all pregnancies are unintended, and the speed is even higher amongst teenagers in the US, researchers said in background notes. This pill could revolutionize family planning.
The targeted enzyme known as soluble adenylyl cyclase (sAC). It contributes to fertility by helping sperm survive and swim upstream to the feminine egg.
“When sperm are deposited into the feminine reproductive tract, they really need to give you the option to swim or move with the intention to give you the option to fertilize an egg,” Lindsey said. “When you take away that motility, then the sperm don’t move. They simply sit there, and that’s what this compound does, it prevents sperm from moving and maturing.”
Some healthy men are naturally infertile because of the same mutation that inhibits soluble adenylyl cyclase, Levin said.
To see whether a brief inhibition of the enzyme would stop pregnancy, Levin and his colleagues tested the experimental drug on a bunch of lab mice. The compound was designed to specifically block soluble adenylyl cyclase.
The female and male mice got busy as expected, but no pregnancies were observed, researchers said. Sperm recovered from the feminine mice afterward remained incapacitated.
The compound wore off three hours later, and males recovered their fertility.
Men with naturally inhibited soluble adenylyl cyclase do have an increased risk of kidney stones, but that happens only when the enzyme is blocked for months or years, Levin said.
“A person would only have sAC inhibitors of their body temporarily so there would never be enough time with sAC inactive for stones to form,” Levin said.
The drug utilized in the mice was a “tool compound” — a chemical utilized in the laboratory to research whether this approach would work, Levin said. Further work must be done to seek out the correct enzyme blocker for humans.
“We don’t consider it sufficiently advanced for taking into humans,” Levin said of the compound. “Our current studies are focused on getting improved versions that are suitable for taking into clinical trials, which we hope can begin in the subsequent two to 3 years.”
However the researchers say this study proves the concept — an on-demand pill for male contraception is feasible.
“Hopefully, someday men might be equal partners in family planning and other people shouldn’t need to take a contraceptive day-after-day of their lives with the intention to control their fertility,” Levin said. “On-demand contraception allows an individual to take contraception only when and as often as needed.”
The approach is “promising,” but there are still some potential hurdles to pass before such a pill is on the market for men, said Dr. Amin Herati, director of male infertility and men’s health at Johns Hopkins Medicine in Baltimore.
“A lot of these non-hormonal contraceptive therapies don’t reach human use since human and murine [mouse] biology are usually not perfectly matched, and the success rates in human clinical trials might not be as robust as a vasectomy,” Herati said. “Any contraceptive developed would want to match vasectomy as the present gold standard.”
More information
The U.S. Centers for Disease Control and Prevention has more on contraception.
SOURCES: Lonny Levin, PhD, professor, pharmacology, Weill Cornell Medicine, Recent York, N.Y.; Christopher Lindsey, PhD, program officer, U.S. National Institute for Child Health and Human Development, Rockville, Md.; Amin Herati, MD, director, male infertility and men’s health, Johns Hopkins Medicine, Baltimore; Nature Communications, Feb. 14, 2023