Vaginal Gel Study Charts New Course for HIV Prevention
A vaginal gel containing Gilead Sciences Inc.’s AIDS drug Viread cut HIV infections by as much as 54 percent in a trial in South Africa, the first time such a product has protected women after six previous gels failed.
Among 445 women who applied the gel before and after sex, there were 39 percent fewer HIV infections overall than among those who used a placebo gel, according to the trial results released today by the journal Science. There were 54 percent fewer infections among those who used the gel more than 80 percent of the time and a 28 percent reduction among those who used it least.
About 2.7 million people are newly infected with AIDS each year, and new methods are needed to curb the epidemic that still ravages countries in sub-Saharan Africa. Previous gels relied on drugs that weren’t specifically designed to target HIV, the virus that causes AIDS. The new approach, in which medicines are used before sex to prevent infection, is also being tested with antiviral pills and rings inserted vaginally once a month, eliminating the need to use the gel every time women have sex.
“It’s a game-changing trial,” said Mitchell Warren, executive director of the New York-based AIDS Vaccine Advocacy Coalition, a nonprofit group, in an interview. “At last, here is now proof of concept that we can use a microbicide against HIV. It’s a transformative moment in prevention science.”
Women who used the gel had the added benefit of being protected from genital herpes, or HSV-2, a disease that increases a person’s susceptibility to HIV infection. Women who used the gel had a 51 percent reduction in new herpes infections, said Salim Abdool Karim, the director of the Centre for the AIDS Programme of Research in South Africa, or Caprisa, which coordinated the study.
Herpes, which causes open lesions in some patients, affects as much as 74 percent of some populations in developing countries, according to the World Health Organization in Geneva. Women who have herpes are twice as likely to acquire HIV, and blocking herpes will help the gel decrease AIDS infections over time, Karim said.
The gel was developed by Conrad, a nonprofit organization based in Arlington, Virginia, and funded by the U.S. and South African governments under royalty-free license from Foster City, California-based Gilead, the world’s biggest maker of AIDS medicines.
The experimental product is the first gel to employ a proven treatment to prevent infections, and may indicate the prospects for five other major trials of the pre-exposure prophylaxis, or PrEP, theory of HIV prevention. Researchers are also testing Viread and Gilead’s Truvada as a means of blocking the virus in gay men, drug users and heterosexuals.
“It’s a fantastic outcome and one that everyone should look to as another step,” Howard Jaffe, chairman of the Gilead Foundation, which manages the company’s relationship with Conrad, said today in an interview. “The bigger line item for Gilead is, what does this mean in terms of PrEP overall? One can’t help but come away from these results and feel even more optimism.”
Gilead, which donated the active ingredient in the gel, won’t participate in the commercialization of the product in developing nations. It’s “an open question” as to whether the company markets it in the U.S. and Europe, he said.
“We’re not in the business of doing vaginal or rectal gels,” Jaffe said. “I’ve always believed that it’s easier to pop a pill than it is to apply a gel.”
Gilead’s top three drugs, which all rely on Viread as a key ingredient, are given to 85 percent of newly diagnosed AIDS patients in the U.S. Gilead shares rose 97 cents, or 3 percent, to $32.91 at 4 p.m. New York time in Nasdaq Stock Market composite trading.
Gels could be made more appealing by emphasizing their ability to increase sexual pleasure, Karim said in a conference call with reporters.
“The future is going to involve making this gel something that is part of the sex act, that enhances sex even,” said Karim. The gel in the trial “is a simple cylindrical white plastic tube. There is no color, no design, nothing. Even Coke would have gone bankrupt if they took this approach in marketing their product.”
A product could be ready as early as 2013 if the results are confirmed by a second study known as Voice that is enrolling patients, said Warren, of the AIDS advocacy group.
“After these results are confirmed in an ongoing and similar study supported by the National Institutes of Health in the U.S. Department of Health and Human Services, as well as other studies, we will work with partners at the global and country levels to integrate this product into programs,” said USAID Administrator Rajiv Shah in a statement.
Conrad gave the rights to manufacture the gel to the government of South Africa to get the product to women in the country most affected by the disease as quickly as possible, said Henry Gabelnick, the nonprofit’s executive director, in a statement.
“It’s not something that can happen overnight, but it should be achievable that when you have a positive result it’s less than three years before it’s scaled up quite substantially,” Bill Gates, the co-founder of Microsoft Corp. told reporters at the biennial International AIDS Conference in Vienna today. His foundation helped fund the trial.
The WHO and the United Nations will meet with the South African government next month to discuss how to speed plans for more testing of the gel, said Cate Hankins, the chief scientific officer of UNAIDS, a UN agency. The Voice trial will take too long to complete, and a quicker study may be developed using the same patients from South Africa trial, she said.
“It’s the first time we have something women can use,” Hankins said in an interview in Vienna. “What’s really important now is to move very, very quickly.”
A study in pregnant women will be needed, Hankins said. Women in the South African trial were taken off the gel if they became pregnant, though there were no signs of complications in those pregnancies. No serious side effects were reported, and there was no evidence of the virus developing resistance to Viread, according to the study.
The results are scheduled to be presented tomorrow at the conference in Vienna.
In studies presented today, Merck & Co.’s Isentress tablets suppressed HIV as successfully as older drugs by Abbott Laboratories and Gilead, and London-based GlaxoSmithKline Plc’s experimental AIDS drug cut virus levels in patients for whom Isentress no longer worked. Research on medicines from Gilead, Glaxo and New Brunswick, New Jersey-based Johnson & Johnson will be reported later this week.
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