A major clinical trial on promising anti-HIV drug Truvada has been ended early after it became clear it would be “highly unlikely” to prove effective in preventing new infections.
Family Health International (FHI), the non-profit overseers of the phase III trial, described the development as “surprising and disappointing”. Many AIDS researchers had high hopes for Truvada, not least because it was recently proven to be effective in preventing infection in gay men.
After reviewing interim data on the FEM-PrEP study an independent monitoring committee concluded the study would be “highly unlikely to be able to demonstrate the effectiveness of Truvada in preventing HIV infection in the study population, even if it continued to its originally planned conclusion”, says FHI (press release).
Although it is not yet possible to say whether or not Truvada can prevent HIV infection in women, the 56 new infections found among trial participants were spread equally among the control group and the group receiving the drug. Possible reasons for not finding a preventive effect include poor adherence and lack of impact in women as opposed to men, says FHI.
“Today’s announcement about the FEM-PrEP study is disappointing,” said Mitchell Warren, executive director of HIV non-profit AVAC (press release). “However, it must be seen as what it is – the closure of a single trial in a field that has generated exciting results in the recent past. Even with this finding, there is still a strong rationale for continuing other trials, including those in women, in hopes of obtaining better results in the future.”
Truvada combines emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF). AVAC notes that two trials continue in sub-Saharan Africa on these compounds. The early closure of this trial should not be seen as predicting the future outcome of these trials, says Warren.