Original content from the Mapping Pathways blog team
An important landmark was achieved on May 10 when a panel of
experts of the U.S. Food and Drug Administration
(FDA) strongly backed the approval
of the first ever drug to prevent sexually acquired HIV infection.
The panel recommended approval of Truvada
(emtricitabine/tenofovirdisoproxilfumarate) for use in PrEP in HIV-uninfected
gay men and other men who have sex with men (MSM), HIV-uninfected partners in
serodiscordant relationships and other individuals “at risk” of acquiring HIV
through sexual activity. The committee voted 19 to 3 in favor of using it for
HIV-uninfected gay/MSM, 19 to 2 (1 abstention) in favor of using it for
HIV-uninfected partners of those with HIV, and 12 to 8 (2 abstentions) in favor
of using it for other “at risk” individuals.
While the FDA is not required to follow the panel’s advice,
it usually does and the final decision is expected by June 15.
One of the main drivers of HIV transmission in the U.S. is
unprotected anal intercourse among gay men and other men who have sex with men
(MSM), who represent approximately 2% of the population but accounted for 61%
of all new HIV infections in 2009, according to the U.S.
Centers for Disease Control and Prevention (CDC.) CDC estimates
approximately 1.2 million people currently living with HIV in the U.S., and
about 50,000 new infections every year. Click here
for more info on the U.S. epidemic.
To support its supplemental drug application, Gilead
Sciences presented findings from the iPrEx
trial and the Partners
PrEP trial, both of which used Truvada in combination with regular HIV testing
and counseling. Condoms and STD screening and treatment were also part of the "prevention package" for all trial participants.
The iPrEX trial indicated that gay/MSM participants who took
Truvada daily had a 44% reduction in HIV incidence over the course of 1.2 years
of follow-up compared with placebo. However, there was low adherence to the
drug with approximately half the men not taking their pills, despite extensive
counseling and other supportive measures. For individuals who did take the drug, and had
detectable levels of drug in their bodies, the efficacy of Truvada was approximately
90%. The Partners PrEP trial (serodiscordant heterosexual couples in Africa) had encouraging results as well with risk of infection reduced by 73% in those
who received Truvada and demonstrated astoundingly
high levels of adherence.
Adherence
was, once again, a major topic of debate among the panel members who pointed
out that taking the pill every single day was critical for the efficacy of
Truvada. If in controlled, clinical trials, patients were not able to take the
drug everyday, how could one ensure that they would take the drug everyday in
the real world, where people are more likely to forget or skip their
medication?
Another concern voiced by the panel members was whether the
use of Truvada would encourage higher-risk behavior among users, like neglecting
to use a condom, which is still the most reliable defense against HIV. (Read an
interesting response to this concern by some members of the HIV prevention
community here.)
The potential FDA approval will allow Gilead to officially
market Truvada as an HIV-prevention strategy. As our Mapping Pathways colleague
Jessica Terlikowski said
last week,“We need to make sure that people are aware of what prevention
strategies exist, so they can access what they need when they need it. We owe
it to the communities to push for both existing tools like male and female
condoms, sterile syringes, PEP, as well as emerging biomedical tools like microbicides
and PrEP.”
The issue of whether the FDA should approve Truvada for use in PrEP continues to be
a source of debate and conversation among the HIV prevention community.
To learn more about PrEP, check out the following links:
[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position. Please look for us on Facebook here www.facebook.com/MappingPathways and you can follow us on Twitter @mappingpathways as well.]
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