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 In 2012, the U.S. Food and Drug Administration approved the pill,
known as Truvada, for so-called pre-exposure prophylaxis (PrEP)
against HIV, the virus that causes AIDS. Uninfected individuals who
take Truvada every day can cut their risk of getting HIV during sex
by more than 90 percent, according to the U.S. Centers for Disease
Control and Prevention (CDC).
In the ANRS IPERGAY trial, gay and bisexual men were randomly
assigned to take Truvada "as needed" - instead of each day - or an
inactive dummy pill. The group taking Truvada had an 86 percent
reduction in new HIV infections, compared to people taking the
placebo.
That phase of the trial ended in 2014, after which the researchers
offered Truvada to all the participants.
After an average of about 18 months, the risk of HIV among the 362
participants fell 97 percent, compared to results with the dummy
pill in the first phase of the study.
Dr. Jean-Michel Molina of Hopital Saint-Louis in Paris, one of the
lead investigators, told Reuters Health he's amazed at how
effectively this strategy prevents HIV.
For the trial, people took two pills two to 24 hours before sex.
They took one tablet 24 hours later, and another tablet 48 hours
later. If they had continuous sexual activity, they were told to
take a pill each day and a pill for the following two days after
last having sex.
During the first part of the trial, there were 6.6 new infections
per year among every 100 people taking the dummy pill, versus only
0.91 new infections per year among every 100 people using PrEP.
When everyone started using "on demand" PrEP, the rate of new
infections fell even further, to 0.19 per 100 people per year.
Molina wasn't surprised that infection rates dropped when everyone
began taking PrEP. "Participants knew the efficacy of on demand PrEP
and were more inclined to use it as recommended," he said in an
email.
Molina and colleagues reported Wednesday at AIDS 2016 in Durban,
South Africa that only one person acquired an HIV infection in the
last phase of the trial. The person had not taken PrEP in months and
had no detectable levels of the drug in his blood at the time of his
diagnosis.
"In France today, two thirds of people on PrEP use it on demand,"
said Molina. "I think it is an interesting alternative for people
who did not want to commit to a daily pill."
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The findings only apply to men who have sex with men, however.
Molina said studies in other populations are in progress.
The researchers also reported that condom use fell in the last phase
of the trial. The decrease was primarily among men who previously
committed to using condoms.
Dr. Bruno Spire of INSERM in Marseille, France, who is also an
investigator on the trial, said condoms were rarely used among
participants in the trial and they were protected from HIV by PrEP.
Without condoms, people are still vulnerable to other infections,
but those are largely treatable, he said. Also, he noted, rates of
other sexually transmitted infections in the study remained
relatively steady.
Spire told Reuters Health that it may be better to empower some
people to decide when they need PrEP. For others, he said, it may be
better to have the pill as part of their daily routine.
When the initial results of IPERGAY were announced last year, the
CDC said in a statement that it "continues to recommend daily dosing
of PrEP and urges people at substantial risk for HIV infection and
their health care providers to continue to follow current CDC
guidelines."
Spire added that the new results can't predict what would happen in
real life, where people are taking the pills on their own and not in
a trial.
SOURCE: http://bit.ly/29O4OCW AIDS 2016, presented July 20, 2016.
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