Indian researchers are now on their way to devise a male contraceptive, Reversible Inhibition of Sperm Under Guidance, which is reversible, non-hormonal and provides 10 or more years of protection after a 10-15 minute procedure.
In the RISUG study, doctors inject a gel into the tube that sperm travel through after they are produced (known as the vas deferens). The gel then disables the sperm as they swim by. In the study involving animals, male fertility returns if the RISUG is flushed out with another injection that dissolves the gel.
Elaine Lissner, director of the non-profit Male Contraception Information Project in San Francisco, says she is not surprised that American men are watching the RISUG trial with keen interest. She emphasises the method has the potential to be the first truly affordable, reversible, long-term male contraceptive.
In 2002, when enrollment in the Indian study was halted, more than 140 men were already using RISUG. Concern about side effects and insufficiency of safety data caused a temporary suspension of the project. However, expert panels subsequently concluded that the major side effect -- several weeks of non-painful scrotal swelling in about a third of the subjects, was not enough to stop the study.
"When we first began using RISUG in volunteers more than 15 years ago, we didn't have access to the more sophisticated toxicity tests available today," says Dr H C Das, one of the lead investigators.
"Last year we sent RISUG to an FDA-registered laboratory in the United States for more tests, and the results came back clean. We've also done more studies at the Industrial Toxicology Research Centre in Lucknow, India, with the latest equipment. We're glad to be able to provide men this additional reassurance," Dr Das said.
Dr R S Sharma, deputy director general of the Indian Council of Medical Research, concurs that the safety results were "very satisfactory". The ICMR is working to arrange study sites throughout India, beginning with Jaipur, Ludhiana, Udhampur, and New Delhi. Three data monitoring committees will watch for any safety concerns.
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