Bill & Melinda Gates Foundation

Understanding the VOICE Trial Results

March 04, 2013

Today, researchers announced that none of the three HIV prevention interventions tested in a large-scale trial called VOICE (Vaginal and Oral Interventions to Control the Epidemic) were effective in  reducing the incidence of new infections among the women who participated in the trial.

The likely explanation for these results is that few of the women who participated in this well-conducted trial funded by the Microbicide Trials Network of the National Institutes of Health used the products that they were prescribed as directed. Those products included a daily oral tenofovir pill, a daily oral TDF/FTC (Truvada) pill, or a daily application of 1% vaginal tenofovir gel.

So what do the VOICE results mean for efforts to identify effective antiretorival (ARV)-based prevention methods that women can initiate and control? We know from other trials that, when women use them, ARV-based prevention methods can be highly effective. But it is clear that the drug regimens used in the VOICE trial didn’t meet the needs of many women. As a result, a large number of women didn’t use them with the frequency necessary to prevent infection. 

As Mitchell Warren of AVAC notes, HIV prevention methods can’t be designed in a vacuum. They must be responsive to the complex social, cultural, and economic realities of women’s and girls’ lives and address women’s specific reproductive and sexual health needs. Researchers can gather important insights from VOICE and other prevention trials about how women perceive their HIV risks, about the factors that encourage health-seeking behavior, and about the products that women prefer to use.

So where do we go from here?

  1. We need to continue with ongoing prevention trials such as FACTS001
  2. We need to pursue the development of less user-dependent products such as long-acting vaginal rings, and intramuscular injections. 
  3. We should carefully evaluate opportunities to combine ARVs for HIV prevention with contraceptive methods. This is because women’s risk perception of pregnancy is higher than their perception of HIV risk and effective contraceptive delivery methods are known.

Beyond ARV-based prevention, it is important  that we stay committed to research to develop  a safe and effective preventive HIV vaccine, the continued scale up of treatment – focused on those most in need – and the continued scale up of voluntary medical male circumcision. 

In the past two decades, we have made considerable progress in reducing HIV incidence and expanding access to treatment. But we still face a reality in which 34 million people are living with HIV, and the number of people who are newly infected still outpaces the number of people who gain access to treatment, by a factor 2:1.

This path ahead will not be easy, and the results of the VOICE trial are a disappointment. But they also provide an opportunity to address fundamental factors that influence prevention product preferences and behaviors.  To turn the tide we must stay committed to discovering and developing HIV prevention and treatment tools that those at risk will want and use.

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