Study: Vaginal gel cuts HIV infections by half

Scientists said Monday that a gel for women had cut the rate of HIV infections in South Africa as much as 54 percent, suggesting a potentially effective way to block male-to-female viral transmission.

Results of the clinical trial of the gel, made by a California biotech company, are expected to be presented Tuesday at the International AIDS Conference in Vienna, marking a milestone in developing medication to prevent HIV infection in women. Past attempts at similar medications produced a series of at least a half dozen failed results.

"The field of vaginal gels and microbicides has been going on for years and most of the results have been disappointing," said Dr. Roy Steigbigel, a microbiologist at Stony Brook University who is testing other forms of therapy to combat HIV. "Obviously, if this is efficacious it would be beneficial to women."

Women who used the gel 80 percent of the time, both before and after sex, received the greatest benefit, their infection rate lowered by more than 50 percent. Overall, results showed a 39 percent reduction, which included women who were not as compliant.

The study included 445 participants.

The gel contains the anti-HIV medication tenofovir, made by Gilead Sciences of Foster City, Calif. The two-year marks the first time such an approach has provided protection against HIV.

"Women represent the majority of new HIV infections globally and urgently need methods they can control to protect themselves from infection," said Dr. Kevin Fenton, director of the national center for HIV/AIDS at the Centers for Disease Control and Prevention.

"It is also very encouraging that the study found that the microbicide significantly reduced the risk of genital herpes, which is common in developing countries and in the United States," said Fenton. Genital herpes facilitates HIV transmission.

The trial was overseen by a research consortium in South Africa. Infectious disease experts in the United States say the study's results would have to be confirmed here and the medication approved by the Food and Drug Administration.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the research is "a significant milestone both for the microbicide research field and HIV prevention as a whole."

He added that research is under way in the United States involving the same drug, but in pill form, not gel. The government-supported research, he said, is aimed at discovering whether the medication's tablet form can prevent infection.