Each year, more than five million people in the United States are infected with human papillomavirus-some strains of which can cause genital warts and cancers-during sex. One of the most common causes of sexually transmitted disease, the virus is highly contagious, and so far, nobody has come up with a way to fight it directly. Doctors can remove the warts with chemicals, lasers or other means, but the virus isn't affected. Now Quebec-based Origenix Technologies is testing a drug the company believes will combat both the warts and the virus by blocking the microbe's ability to replicate.

The drug is a specially modified DNA molecule that interferes with one of the genes the virus uses to replicate itself once it infects a human cell. Origenix has completed animal testing of a cream containing the drug, says executive vice president Anthony Payne. The company hopes to begin U.S. clinical trials this summer.