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 The result doesn’t represent all users of the drug, Truvada, and it
doesn’t prove that taking the drug leads men to have riskier sex,
researchers said. The result also stands in contrast to two rigorous
peer-reviewed trials of the drug.
The doctor who conducted the survey said the finding is leading to a
formal study.
“We need more information to really clarify the information we do
have,” said Dr. Jonathan Volk, who helped conduct the survey at
Kaiser Permanente in San Francisco.
Truvada, which is manufactured by Gilead, is approved in the U.S.
for pre-exposure prophylaxis or PrEP. The pill may reduce the risk
of HIV infection, which leads to AIDS, by as much as 92 percent,
according to the U.S. Centers for Disease Control and Prevention.
As of right now, Volk said the survey shows the drug is working to
prevent HIV.
"We now have over 500 patients on this medication and we have zero
new infections," he said.
The CDC advises people taking Truvada to continue using condoms,
because the pill does not completely protect against HIV and does
not protect against other sexually transmitted infections, which are
effectively prevented through condom use.
Volk told Reuters Health by phone that he decided to survey around
100 of his patients who had been taking Truvada for about six months
to get a better understanding about their behaviors and experiences
with the drug. The results have not been peer-reviewed for
publication in a journal.
The vast majority of the patients are men who have sex with men,
Volk said.
Of 90 men who responded to the survey, 45 percent reported decreased
condom use since starting on the drug.
“We can’t say that PreP is causing people to make that decision,”
Volk said.
He added that there is a lot they don’t know about the men who
responded to the survey. For example, they don’t know how many are
in committed, monogamous relationships. They also don’t know to what
degree condom use decreased.
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The researchers didn’t compare the respondents to another group of
men who don’t take the drug, so they can't tell if condom use is
declining among non-Truvada users, too.
For example, if men stop wearing condoms when they’re in a committed
relationship with one person, a comparison group not using PreP
might show a similar decline in condom use among some men.
Alternatively, Volk said it could be that people's condom use would
change over time and decrease anyway.
“We can’t really determine that without the control group,” he said.
Volk said it could be that they're reaching exactly the right people
at the right time, because their condom use would decrease anyway.
"These are important clinical questions that we need to look at and
plan to formally, but not from the data we have now," he said.
The survey results contrast with a 2013 randomized clinical trial –
considered the highest quality medical evidence – among
approximately 2,500 men and transsexual women in six countries.
Although participants did not know whether they were getting Truvada
or a dummy pill, rates of HIV and syphilis infection fell,
suggesting a decrease in risky behavior (see Reuters story of
December 18, 2013 here: http://reut.rs/1zUL0DR).
Volk said he received a grant from Kaiser Permanente to study
Truvada users. The study will look at adherence, outcomes and side
effects.
As of right now, he said, "The major point is that this drug was
approved for preventing HIV and if anything our experience supports
that this medication is working."
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