The long wait for a durable and yet reversible male contraceptive may finally come to an end soon as researchers have found that a single injection of a new contraceptive called Vasalgel can provide males condom-free sex for a year.
Men currently have few options for reproductive control, including condoms and vasectomy. While condoms are widely available and useful in preventing disease when used correctly, they have an 18 percent yearly pregnancy rate in typical use.
Vasectomy is effective, but must generally be considered permanent. There are no long-acting, reversible contraceptives currently available for men.
In preclinical trials with rabbits, the researchers confirmed that the contraceptive effect of Vasalgel was durable over the 12 month study period.
"Results from our study in rabbits were even better than expected,” said lead author of the study Donald Waller, professor at University of Illinois at Chicago, US.
"Vasalgel produces a very rapid contraceptive effect which lasted throughout the study due to its unique hydrogel properties. These features are important considerations for a contraceptive product to be used in humans," Waller noted.
The findings were published in the journal Basic and Clinical Andrology.
Vasalgel, developed by US-based non-profit company Parsemus Foundation, consists of styrene-alt-maleic acid (SMA) dissolved in dimethyl sulfoxide and could be the first long-acting, non-hormonal, potentially reversible male contraceptive to reach market, the researchers said.
After the gel was injected into the duct which conveys sperm from the testicle to the urethra - the vas deferens - of 12 rabbits, semen analysis revealed that 11 rabbits were azoospermic, having no quantifiable sperm in their semen at all.
One rabbit had a few samples with very small numbers of sperm before also becoming azoospermic.
Human trial for Vasalgel is scheduled to begin later this year, the developers said.
"Contraceptive development is a hugely expensive project. But this is not just another early-stage lead; we're so close on this one. It's time to finish the job we've started," Elaine Lissner, executive director of Parsemus Foundation said.
