Virus-Blocking Gels Are Said to Shield Women From HIV

Work toward developing virus-blocking vaginal gels and other methods that women can use to protect themselves from HIV infection is making slow but steady progress, according to research discussed Wednesday at the International AIDS Conference here.

One group of researchers reported that a vaginal ring, designed to gradually release doses of antiviral drugs, passed its initial safety tests and consistently dispensed the drug for seven days.

In a separate study, trials of antiviral gels in monkeys also produced some protection against an HIV-like virus, in some cases for days when regularly applied.

Prevention and the empowerment of women have been prominent themes at the conference, with many speakers, including Microsoft Corp. Chairman Bill Gates -- a major funder of AIDS programs -- touting the benefits of these so-called microbicides because they give women the ability to protect themselves.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, made a special point to mention microbicides in his speech Wednesday on the history and future of AIDS research.

“HIV is progressively taking on the face of a woman,” Fauci said. “It is absolutely essential we address the special concerns of women in protecting themselves.”

Microbicides are “eminently doable” from a scientific point of view, Fauci said later. “There is no overwhelming scientific reason why we can’t have one.”

Five gel-based microbicides are in their final stages of clinical trials, and results could be presented as early as next year.

These first-generation microbicides have to be used immediately before sex. But many second-generation microbicides, using more sophisticated antiviral drugs, could be taken any time of day or even days in advance. Development of these drugs trails the first generation by several years.

The concept of microbicides has been around since the early 1990s but wasn’t intensely pursued because researchers were focused on developing an AIDS vaccine, said John P. Moore, a professor of microbiology and immunology at Weill Medical College of Cornell University in New York who presented the study on microbicide use in monkeys.

“It’s becoming increasingly realized that developing a vaccine is extraordinarily difficult,” Moore said. “In the absence of a vaccine, alternative prevention technologies have got to be on the forefront.”

Microbicides have the advantage of attacking HIV just as it is struggling to establish itself in a new host, said Dr. Rupert Kaul, who studies HIV at the University of Toronto and was not involved in the monkey or vaginal ring trial.

A woman’s genital tract is already inhospitable to the virus, he said. “If you can just improve what we already can do a little bit by ourselves, we can have a big impact on HIV transmission,” Kaul said.

Microbicides also appear to stay localized and do not spread throughout the body, like pills do. This could help limit their toxic effects.

Kaul, however, cautioned against too much optimism.

A trial in 2002 of a contraceptive cream, Nonoxyl-9, that was thought to guard against HIV, found it actually helped HIV infect women because it could cause ulcers that eased the virus’ entry into the body.

The Maryland-based International Partnership for Microbicides, which led the vaginal ring study, has begun market research in South Africa, Kenya and Zambia to see whether women will use the gels.

Zeda Rosenberg, the group’s chief executive and a coauthor of the vaginal ring study, said responses had been encouraging.

“When we ask women what they prefer to use, they say they will use something, even if it’s not ideal, if it’s the only thing available for them to prevent HIV,” she said.