Drugs May Prevent HIV Spread Among
WEDNESDAY, July 13 (HealthDay News) -- Giving antiretroviral
drugs to heterosexuals at high risk of HIV infection can
significantly reduce the chance they will develop the AIDS-causing
virus, two new studies suggest.
"This is an extremely exciting finding for the field of HIV prevention," said Dr. Jared Baeten, co-chair of one study and a University of Washington associate professor of global health.
Both trials were done in Africa. In one, a daily dose of
Truvada, a combination pill that includes tenofovir disoproxil
fumarate and emtricitabine, reduced the risk of getting HIV from
infected partners by about 63 percent.
The other study found that two different regimens -- tenofovir,
sold as Viread, and Truvada -- also reduced the risk of
transmission through heterosexual sex.
Using antiretrovirals in this way is called pre-exposure
prophylaxis, or PrEP.
Earlier research found that PrEP reduced HIV transmission among
gay and bisexual men, but whether it could prevent HIV infection
among heterosexuals was unknown.
A subsequent trial, reported in May, that involved heterosexuals
found that people with HIV could reduce the risk of infecting their
sex partners by more than 90 percent if they started treatment with
antiretroviral drugs when their immune system was still relatively
The latest research includes a trial conducted by the U.S.
Centers for Disease Control and Prevention (CDC) and the Botswana
Ministry of Health. For that study, researchers assigned 1,219
HIV-negative men and women to a daily dose of Truvada or a dummy
pill. All the participants also received HIV prevention services,
including condoms, risk-reduction counseling and testing and
treatment for sexually transmitted diseases, according to the
Nine of those taking Truvada became HIV-positive, compared with
24 of those taking the placebo. That is a 62.6 percent reduced risk
for those on Truvada, the researchers said.
Among those who continued taking the pill, the risk reduction
was greater -- 77.9 percent.
No significant safety concerns were associated with Truvada, the
study said, although people taking it were more likely to report
nausea, vomiting and dizziness than those taking placebo.
The other new trial, called the Partners PrEP study, was headed
up by the University of Washington and funded by the Bill &
Melinda Gates Foundation. The placebo portion of the study was
halted sooner than expected because early findings so strongly
indicated that the pill prevented the spread of HIV. That led to
the CDC releasing the results of its study early as well, on
The Partners PrEP trial, done in Kenya and Uganda, included
4,758 couples with one partner who was HIV-positive. Individuals
without HIV were randomly assigned to a single drug (Viread), a
drug combination (Truvada) or a placebo.
As of late May, 78 HIV infections had occurred; 18 of them in
the Viread group, 13 taking Truvada, and 47 who took the dummy
For those getting Viread, the single drug, the risk of
developing HIV was reduced 62 percent, while the two-drug
combination reduced the risk 73 percent compared with placebo, the
"Now, more than ever, the priority for HIV prevention research must be on how to deliver successful prevention strategies, like PrEP, to populations in greatest need," said Baeten in the statement.
Truvada is approved by the U.S. Food and Drug Administration for
use in combination with other antiretroviral agents to treat HIV-1
infection in adults and children 12 and older. It has not been
approved for PrEP.
Based on the new study results, the CDC will start working to
develop guidance on the use of PrEP among heterosexuals in the
United States, the agency said.
"To use PrEP in the United States we would use basically the same guidelines -- someone who is truly at risk for HIV," said Dr. Margaret A. Fischl, professor of medicine and director of the AIDS Clinical Research Unit and co-director of the University of Miami Developmental Center for AIDS Research, commenting on the study.
Those at high-risk have multiple sex partners, use intravenous
drugs or have multiple sexually transmitted diseases, Fischl said.
"You are talking about a group that is at risk for multiple
sexually transmitted diseases including HIV," she said.
However, it might be difficult to get the drugs to the people
who need them, Fischl said.
"In addition, we need to identify people with HIV and get them into care, because in doing that we know that we decrease the transmission of HIV," Fischl said.
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