AIDS Gels Show Prevention Promise-Researchers

Gels to protect women from infection with the AIDS virus have shown hints that they may work, researchers said on Monday.

One study of 3,000 women showed a gel made by Massachusetts-based Indevus Pharmaceuticals cut transmission rates by a third, and two studies in monkeys suggested that Gilead Sciences Inc.'s drug Truvada might prevent infection when taken as a pill or used in a gel.

The studies presented at a meeting of AIDS in Canada show possible ways to slow the pandemic of deadly human immunodeficiency virus, which infects 33 million people globally and which has killed 25 million.

Dr. Salim Abdool Karim of the Center for the AIDS Program of Research in South Africa and colleagues tested a gel Indevus's PRO 2000 in women who did not have HIV but whose husbands were infected.

Although they were only testing its safety, PRO 2000 actually reduced the rate of HIV infection by a third, they told the meeting.

"This is the first study that now shows that we have a promising candidate," Karim told a news conference.

"We do not regard it as a definitive conclusion that PRO 2000 is a microbicide, but we certainly view it as very promising."

The human immunodeficiency virus is especially common among men who have sex with other men but in Africa, the continent hardest hit by AIDS, women are most likely to be infected, often by their husbands.

"How would you convey to a woman in a rural community who is married and trying to have children how to protect herself from HIV?" asked Karim. "We cannot promote abstinence. We cannot promote faithfulness because she is very faithful," he added.

"We cannot promote condom use because she is trying to have children."

The researchers tested another microbicide called BufferGel made by ReProtect Inc, but were unable to find any significant indication that it helped. The study was only designed to show the gels were safe, an especially important issue because other studies have shown would-be microbicides actually raised the risk of infection.

Work is ongoing to see whether PRO 2000 or BufferGel really do protect women.

"Although more data are needed to conclusively determine whether PRO 2000 protects women from HIV infection, the results of this study are encouraging," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which helped fund the study, said in a statement.

Two studies in monkeys showed combinations of Gilead's HOV drug Viread, or tenofovir, combined with its newer drug emtricitabine, marketed under the brand name Truvada, could protect monkeys from infection with a monkey virus similar to HIV both when used as gels or in pills.

Dr. Gerardo Garcia-Lerma and colleagues at the U.S. Centers for Disease Control and Prevention gave Viread and Truvada pills to monkeys in an approach called pre-exposure prophylaxis and found the monkeys were completely protected.

CDC's Drs. Charles Dobard and Walid Heneine treated monkeys with one of two gels, one containing Viread alone and one with both drugs. Either gel worked equally well in protecting the monkeys, they told the meeting.