Agence France Presse (11.26.11) - Tuesday, November 29, 2011
A routine review of data from a large clinical trial found
that a tenofovir-based vaginal gel was not effective in
preventing HIV in women, researchers reported Friday.
Since the review found no safety concerns with the gel, women
in the vaginal gel arms of the VOICE (Vaginal and Oral
Interventions to Control the Epidemic) study will be told to
discontinue its use at their next regularly scheduled clinic
visit, the Microbicides Trial Network said.
In 2010, the CAPRISA (Center for the AIDS Program of Research
in South Africa) study in South Africa found a tenofovir-based
microbicide vaginal gel was 39 percent more effective than
placebo gel when used before and after sex. In regular users,
it was 54 percent effective. The VOICE study, begun in 2009
with 5,029 sexually active HIV-negative women in South Africa,
Uganda, and Zimbabwe, was expected to back those findings.
Instead, the interim data review found no difference between
the tenofovir gel and placebo, with an annual HIV incidence of
6 percent in the placebo group, compared with 6.1 percent for
tenofovir gel users.
Although VOICE previously scrapped a trial of oral tenofovir
for lacking efficacy, it is continuing to study the safety and
effectiveness of oral Truvada (tenofovir and emtricitabine)
taken daily to prevent HIV, or pre-exposure prophylaxis
"For now, the study will continue and we will work to complete
the remaining visits for the women continuing in the study,"
wrote researchers Sharon Hillier and Ian McGowan. "We are all
eager to understand whether adherence, our daily dosing
strategy, inflammation or other factors could explain the lack
of oral and vaginal tenofovir effectiveness in VOICE. We will
not likely have all of the assays completed until later next
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