Vaginal gel won’t protect women against HIV

The search for an anti-HIV microbicide continues, after a new trial has refuted the results of a previous study that found one to be effective.
New study finds that vaginal gel is not effective in protecting against HIV infection.(Reuters)

A vaginal gel thought to reduce women’s chances of contracting HIV during sex has proven to be ineffective, according to a large-scale study conducted by the Follow-on African Consortium for Tenofovir Studies (Facts), a South African research consortium.

The results of the study, known as Facts 001, were revealed on Tuesday at the annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle in the US.

The Facts 001 results refute the findings of a similar study published in 2010 by the Center for the AIDS Program of Research in South Africa (Caprisa). Researchers in the Caprisa study sampled over 900 women in the KwaZulu-Natal province and reported that the tenofovir gel was 39% effective at reducing the rate of HIV infection among these women.

The rate of new HIV infections in South Africa, measured at 12.2 % in 2012, is the highest in the world, according to the Human Sciences Research Council’s National HIV Prevalence, Incidence and Behavior Survey. The rate is especially high among women, which has fueled research into preventative treatments that target women, such as vaginal gels, rings and injectables loaded with HIV-fighting drugs known as antiretroviral drugs.

HIV prevention tools a priority
During the three-year Facts study, researchers recruited over 2 000 sexually active HIV-negative women between ages 18 and 30, and gave half of them a placebo gel and the other half a vaginal gel containing tenofovir, an antiretroviral drug. Tenofovir gel is a type of microbicide, a compound which is applied to the rectum or vagina to protect against HIV and other sexually transmitted infections.

Researchers then measured the rate of HIV infection between the two groups and observed that women given the tenofovir gel contracted HIV at the same rate as women given the placebo. In total, 123 women became infected, of which 61 were part of the tenofovir gel group, while 62 were given the placebo.

Women in the study were instructed to apply the gel before and after every sexual encounter. Professor Helen Rees, co-chair of Facts, suggested that the method of delivery was not ideal.

“A product that is applied around the time of sex may be suitable for some women, but it did not meet the needs of the majority in our study, most of whom were young, single and lived with their parents,” Rees said in a press statement released by Facts. “Methods that are easier for women to incorporate into their lives are likely to be more effective.”

Responding to the Facts 001 findings, Quarraisha Abdool Karim, leader of the Caprisa trial, said in a statement: “Tenofovir gel prevents HIV infection when it is used, but most of the women in the Facts study did not manage to apply the gel consistently when they had sex.

“While the results are disappointing, the high HIV infection rates in this trial highlight the urgent need for continued efforts to find appropriate HIV prevention tools for women in Africa.”

Microbicides in clinical testing
The Facts 001 findings are similar to those of the Vaginal and Oral Interventions to Control the Epidemic (Voice) trial, which were released at the CROI conference in 2013. The Voice study, involving over 2 000 women in three African countries, found no significant difference between women using tenofovir gel and those using a placebo – but the study was also criticized for having a low number of women actually following the dosing regimen.

Research on tenofovir gel, along with other microbicides, continues, along with research on other types of preventive treatment. So far no microbicides have been made commercially available. However, according to the World Health Organization, 23 are undergoing various stages of clinical testing.

Despite the disappointing findings, Facts reports that the study “reinforces the need for continued research to develop women-centered HIV prevention methods”.

By: M&G 24.02.2015 Joan Koka

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