The Vaginal and Oral Interventions to Control the Epidemic (VOICE) trial assessed the effect of taking any of three antiretroviral medicines — oral tenofovir tablets, oral Truvada tablets or vaginal tenofovir gel — in preventing HIV.
The study involved 5,029 women in South Africa, Uganda and Zimbabwe from 2009 to 2012. Adherence rates were determined based on self-reporting from participants and counts of unused applicators and pills.
“What we presented was an in-depth analysis of that divergence between behaviour and biological measure of endurance based on drug detection in biological specimens.”
Ariane van der Straten, RTI International.
The first result of the trial, which was presented last year, showed that none of the three medicines was effective.
But the results of a new analysis based on blood samples, presented at the 21st Conference on Retroviruses and Opportunistic Infections on 4 March at Boston in the United States, gives insight into the challenges of self-reporting and treatment mechanisms for the Sub-Saharan Africa population.
The new analysis reveals that despite a 90 per cent adherence rate reported by the women, only 25 per cent actually used the products.
“What we presented was an in-depth analysis of that divergence between behaviour and biological measure of endurance based on drug detection in biological specimens,” says VOICE lead researcher, Ariane van der Straten, a senior research scientist at the US-based RTI International.
Van der Straten attributes the poor adherence rates to factors, including the burden of taking a daily treatment product and safety concerns among the women. “There was concern about taking ARV [antiretroviral] drugs as prevention as they are conceived as treatment drugs. So, there was a worry of being ‘pegged’ as HIV positive,” she says.
Two social and behavioural sub-studies, VOICE C and VOICE D, will explore the reason high-risk women did not follow the study process, van der Straten adds. Results are expected later this year.
The current VOICE analysis, however, is already making an impact in the HIV research community, says Deborah Baron, programme manager at South Africa’s Wits Reproductive Health. “When those of us in the field initially heard the  results, we were surprised and were discouraged. However, we have learned a lot from the study,” Baron says.
The adherence protocol was enhanced with real-time batch testing. “This is a tool researchers could use to intervene in real time, rather than at the end of a study, as we saw in VOICE,” says Baron. “But it must be done carefully to ensure you don’t unblind the study.”
The new study sheds light on the mechanism for treatment of patients with HIV in Africa. Women do not want interventions that will require that they use them daily, but may prefer those to be taken weekly, says Gita Ramjee, director of the South African Medical Research Council’s HIV prevention programme.
The council is currently involved in two studies testing the efficacy of a vaginal ring that contains an antiretroviral agent and is inserted for 30 days. Results are expected in late 2015.
This article has been produced by SciDev.Net's Sub-Saharan Africa desk.