Gilead Drug Used in a Vaginal Gel Cuts Women's AIDS Risk

The 2010 International AIDS Conference in Vienna is still underway, but already some studies released there show the constant advances made in the attempts to slow the pandemic. As the world hopes for an HIV vaccine following recent positive developments, a new study in South Africa shows that a vaginal gel made using Gilead Sciences' (GILD) AIDS drug Viread cut HIV infections in women by as much as 50%.

Gilead's HIV drug Viread, or tenofovir, is used as a pill in AIDS treatment cocktails and was supplied royalty-free for the purpose of the study. This is the first time such a microbicide product -- an antiretroviral drug in a gel form -- has protected users after previous attempts failed. In addition, a surprising and positive finding of the trial is that the gel also reduced the risk of genital herpes infection by 51%.

"Tenofovir gel could fill an important HIV prevention gap by empowering women who are unable to successfully negotiate mutual faithfulness or condom use with their male partners," said study co-principal investigator Dr. Quarraisha Abdool Karim, associate director of CAPRISA and associate professor of epidemiology at Columbia University. "This new technology has the potential to alter the course of the HIV epidemic, especially in southern Africa where young women bear the brunt of this devastating disease."

On the Market by 2013?

Most of the world's 33.4 million people who live with HIV/AIDS are in Africa, where the highest burden of HIV infection is among women younger than 30 years. The trial involved 889 women in Durban and a remote rural village in South Africa. Half the women were given the gel containing the medicine to use before and after sex, while half were given a placebo gel.

After one year, the study results showed the gel lowered the risk of infection by 50%. After two-and-a-half years, the gel reduced the rate of infection by 39%. The lower level of effectiveness in the second year was associated with a drop-off in usage by women who became infected with HIV. Also, there were 54% fewer infections among those who used the gel more than 80% of the time and a 28% reduction among those who used it least.

While the study used the gold standard for clinical research, some flaws would prevent applying for regulatory approval of the gel. But if the study results are confirmed in a second trial known as Voice, which is already enrolling patients, a product could be ready as early as 2013, according to Bloomberg.

The "study is an exciting scientific achievement that moves us one step forward to gaining another effective tool to prevent HIV infection," said National Institute of Allergy and Infectious Diseases Director Anthony Fauci in a statement.

Gilead holds the top two slots with its Truvada and Atripla (a Gilead/Bristol-Myers Squibb [BMY] med) in Reuters top 10 best-selling AIDS medicines. Viread is in seventh place. ViiV, the GlaxoSmithKline (GSK)-Pfizer (PFE) partnership, also has three drugs in the top 10, but in the fifth, eighth and 10th spots. Bristol, Abbott Laboratories (ABT), Merck (MRK) and Johnson & Johnson (JNJ) drugs occupy the rest of the slots in the top 10. But with generic competition looming, the market could peak at 2012 if no new drugs come to market. Gilead closed the day up 3.04%, or 97 cents, to $32.91.