Preliminary Safety and Adherence Data from Oral PrEP Trial Released; Trial Not Designed to Evaluate Effectiveness
Friday, July 23, 2010
For immediate release:
Friday, July 23, 2010
11:00 am Vienna / 5:00 am EDT
Contacts:
Mitchell Warren, +1-914-661-1536, mitchell@avac.org
Kay
Marshall, +1-347-249-6375, kay@avac.org
New York, NY – Preliminary data
were presented today at the International AIDS
Conference by the US Centers for Disease
Control and Prevention (CDC) from a safety and
acceptability trial of daily use of oral
tenofovir in HIV-negative gay men and other men
who have sex with men (MSM) in the United
States. These data, which do not include any
evaluation of PrEP effectiveness, add to the
body of information about ARV-based prevention
available to researchers, policy makers,
community and other stakeholders.
This
trial, known as CDC 4323, is one of several
trials around the world testing the use of
antiretroviral drugs to prevent HIV infection,
a concept known as PrEP, or pre-exposure
prophylaxis.
The findings presented
today showed that no serious safety concerns
emerged in the initial analyses. CDC also
shared early findings about risk-taking among
men in the study. The trial was designed so
that some men began taking the daily oral
tenofovir or a placebo pill immediately, while
other participants were delayed by nine months.
This design allowed the research team to gather
information on how pill-taking affected sexual
behavior in participants who were all receiving
the same standard prevention package, including
counseling about safe sex, condoms and STD
testing for the duration of the trial. The
preliminary analyses indicate that rates of
risk behaviors were comparable between the
participants randomized to begin taking
tenofovir or placebo pills daily immediately
compared to those who began after nine months
of trial participation.
Importantly,
these results did not provide any information
on whether PrEP reduces the risk HIV infection.
This trial focused solely on safety and
behavior issues and was not designed to explore
possible effectiveness of PrEP. Several studies
that are studying possible PrEP effectiveness
are currently underway.
“The
information from this trial provides important
pieces of information about the possible use of
PrEP if it is proven effective in other ongoing
effectiveness trials around the world,” said
Mitchell Warren, AVAC executive director. “It
is encouraging to hear there were no serious
safety concerns and that the men in the study
did not appear to increase risk-taking
behaviors while taking a pill.”
“But
much more safety, adherence and risk data will
be needed before PrEP can be implemented if it
is proven effective. And, importantly, this
trial does not tell us anything about whether
or not PrEP will work to reduce the risk of
infection,” Warren added.
“Antiretroviral-based prevention
research shows great promises, especially in
the light of the positive results from the
CAPRISA 004 microbicide proof-of-concept study
released earlier this week. Although the CDC
safety study used oral tenofovir, the same
antiretroviral that was formulated as a gel in
the CAPRISA 004 microbicide study, it is
important not to extrapolate between the two
studies. There are a series of ongoing trials
that still need to be completed before we know
whether PrEP can be added to our list of
available HIV prevention options. Each of these
trials provides a piece of the puzzle of how
antiretrovirals might be used by HIV-negative
people to reduce their risk of acquiring
HIV,” Warren said.
More information
about PrEP research is available in AVAC’s
publication A Cascade of Hope and Questions:
Anticipating results of ARV-based HIV
prevention trials, available at avac@avac.org.