Tenofovir

Tenofovir Gel Overview

Tenofovir is an antiretroviral drug that works by preventing HIV from growing inside human cells and, taken in pill form, tenofovir is a common component of various three-drug cocktails that are used to treat HIV infections. In 2006, Gilead Sciences granted a co-exclusive, royalty-free license to CONRAD and the International Partnership for Microbicides to develop tenofovir into a vaginal gel that could be used by women in developing countries to prevent HIV.

CONRAD researchers conducted a number of preclinical and safety trials to develop a gel that would be safe to test in women. In 2010, researchers at the Centre for the AIDS Programme of Research in South Africa (CAPRISA) completed a study (CAPRISA 004) of 889 women who inserted tenofovir gel in their vaginas before and after sex, and found that it was 39% effective in reducing a woman’s risk of becoming infected with HIV and 51% effective in preventing genital herpes infections. The CAPRISA researchers found that the protective effect against HIV increased as use of tenofovir gel increased: Women who used the gel in more than 80% of their sex acts had a 54% reduction in HIV infections, whereas those who used the gel in less than half of their sex acts had a 28% reduction in HIV infections. Research has shown that women with genital herpes are more likely to become infected with HIV, so the additional protection against genital herpes infection creates a second mechanism whereby the gel may have an even bigger impact in preventing HIV.  Additional studies are necessary to confirm the findings of the CAPRISA 004 trial and only when drug regulatory authorities determine that tenofovir gel is safe and effective for HIV prevention, can the gel be made available for distribution and sale.

VOICE, an ongoing trial conducted by the Microbicides Trial Network (MTN), studied the effectiveness of tenofovir gel inserted into the vagina once a day.  Daily use of the gel was not found to be effective in preventing HIV infection. However, data from the VOICE trial will be helpful in contributing to the overall knowledge of tenofovir gel. For more information on the VOICE trial and other studies of tenofovir gel conducted by the MTN, please click here.

In 2011, a nine-site trial in South Africa being conducted by the Follow-on African Consortium for Tenofovir Studies (FACTS) and replicates the CAPRISA study was launched.  This FACTS 001 trial is testing the effectiveness of the gel in preventing HIV and herpes infections when used before and after sex. Should the study find that the gel is at least as effective as in the CAPRISA 004 trial, it may receive regulatory approval, but approval will not occur before 2015.  CONRAD is the sponsor of the FACTS 001 study.  For more information on FACTS, please click here.

While it is difficult to predict the results of the ongoing FACTS 001 trial, it is important to prepare for success and regulatory approval. CONRAD and the South African Government’s Technology Innovation Agency (TIA) created a license agreement that grants TIA the rights to manufacture and distribute tenofovir gel in Africa, pending approval. 

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