A large clinical trial in India is looking to establish the effectiveness and safety of a new male contraceptive method known as RISUG (Reversible Inhibition of Sperm Under Guidance). RISUG uses a non-hormonal contraceptive gel that that is implanted in the testes and provides 10 or more years of protection. Importantly, the RISUG procedure is considered to be easily reversible, which is not the case with vasectomy procedures. In the RISUG procedure, which only takes around 10 minutes, doctors inject a spermicidal gel into the tube (known as the vas deferens) that sperm travel through after they are produced. The gel disables the sperm as they swim by, rendering a long-term contraceptive effect. The researchers say the effect can be reversed easily by administering another injection that dissolves the contraceptive gel. In tests with monkeys, researchers have injected and reversed RISUG multiple times and encountered no difficulties.
Another advantage is that unlike a vasectomy, RISUG is effective almost immediately, compared to a time to infertility for vasectomy of up to three months.
The results of a recent trial using RISUG found that azoospermia (the absence of sperm) was recorded as early as five days after the implantation. And the researchers say that any sperm that were found in the first months, were either too few or too sluggish to reach an egg. Although the men in the trial were advised to wait at least three days for the polymer to fully anchor itself before having sex and to use condoms for the first ten days, there were no pregnancies in the first months despite some men not following that recommendation.
Elaine Lissner, Director of the Male Contraception Information Project in San Francisco, believes that the RISUG method has the potential to be the first truly affordable, reversible, long-term male contraceptive. But Lissner cautions that there is still some way to go. "A reversibility study in men is key," she stresses. Currently, RISUG's Indian developers are collaborating with US researchers on the path to gain FDA approval.
But it's likely that studies in North American men would not start for several years. "We shouldn't be discouraged. We already know that RISUG works, which is half the battle in drug development. Men in studies in India have been using it for more than a decade. Now we just have to finish our homework," said Lissner.
Based on material from the Male Contraception Information Project
