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Mwansa Njelesani [ profile ] |
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A Pill to Prevent HIV? What the New iPrEx Results Mean for Women
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Nov 24th, 2010 - 03:16:58 |
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FYI
A Pill to Prevent HIV? What the New iPrEx Results Mean for Women
Online: http://www.rhrealitycheck.org/blog/2010/11/23/pill-prevent-what-iprex-results-mean-women
ShareBy Anna Forbes
November 23, 2010 - 9:45am
Published under: STI/HIV/AIDS Prevention | Womens Rights | AIDS |
anal sex | condoms | gender | HIV | HIV prevention | iPrEx |
microbicides | sexual negotiation | vaginal success | women
Anna Forbes's blog | Printer-friendly version | Login or register to
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Pill May Prevent HIV -- its an attention-getting headline. On
November 23, the announced results of a clinical trial conducted in
Peru, Ecuador, Brazil, the United States, South Africa and Thailand
showed that taking an antiretroviral drug (in the class of those used
to treat HIV/AIDS) may help prevent an HIV-negative person from
becoming infected if exposed to HIV. The study, called iPrEX
(Iniciativa Prophylaxis in Spanish or the Pre-exposure Prophylaxis
Initiative in English) showed that, overall, those taking the
medication were 44 percent less likely to become infected than
participants using the placebo pills. Researchers also reported that
the study participants who took the drug strictly according to
schedule and did not miss doses were 73 percent less likely to become
infected.
Pre-exposure Prophylaxis (PrEP) refers to the practice of using
medicine to prevent yourself from getting a disease or condition
before you are exposed (pre-exposure) to the thing that can cause it.
You take malaria medication, for example, before traveling to areas
where you may be bitten by mosquitoes that carry malaria. Having the
medicine already in your system greatly reduces your chances of
getting malaria if you are bitten. Some people who are severely
allergic to cats may take an allergy medication before visiting a
friend who has cats another form of PrEP. In this case, the iPrEx
trial showed that HIV-negative people can reduce their risk of
acquiring HIV by taking an antiretroviral pill every day. Obviously,
this strategy is nowhere nearly as effective as using condoms or
having sex only with people who are HIV negative. But it may be a
good prevention tool for people who are at high risk of HIV because
they do not or cannot use those risk reduction strategies.
Started in June 2007, the iPrEx study ended in 2009 after enrolling
2,499 HIV-negative gay men, male-to-female transgendered women, and
other men who have sex with men (MSM). It was conducted at 11 sites
in six countries: two sites in Lima, Peru, one site in Iquitos, Peru,
one site in Guayaquil, Ecuador, one site in Boston and one site in San
Francisco in the United States, one site in Cape Town, South Africa,
two sites in Rio de Janeiro and one site in Sao Paulo, Brazil and one
site in Chiang Mai, Thailand. These locations were selected because
the prevalence of HIV infection among the men and transgender women
having sex with men there is extraordinarily high, between 10 and 28
percent. The iPrEx study was funded by the US National Institutes of
Health (NIH) and the Bill and Melinda Gates Foundation. The
medication tested in the study was donated by their manufacturer,
Gilead Sciences.
Proof that PrEP works that there is, literally, a pill can help to
prevent HIV -- is an extraordinary breakthrough, as was the news
received last summer that an effective vaginal microbicide had been
identified. But what does a study focused on people engaging in
rectal-penile sex have to do with women and their reproductive health?
There are many ways to answer that question -- some of them cause for
celebration and some reasons for real concern. Consider the following:
1. What do the iPrEx results mean for women?
Its great to know that PrEP may be an effective HIV prevention tool
that women could use on their own, without a partners cooperation.
Taken orally, the drug goes into the bloodstream and could help
protect women who are having vaginal sex, anal sex or are exposed to
HIV through other means. They may actually be of particular interest
to women who have anal sex because many report that it is easier to
insist on condom use during vaginal sex, where they can make the
pregnancy prevention argument, than it is during anal sex. This puts
them at serious risk because, although estimates vary, unprotected
receptive anal intercourse with an infected partner is probably five
to twenty times more likely to transmit HIV than receptive vaginal
sex.
Between 10 percent and 35 percent of heterosexual women in the US and
UK acknowledge practicing receptive anal intercourse. Among American
men, 40 percent report having engaged in anal intercourse with a woman
at some point in their lived.
Clearly, we cant assume that the PrEP medications tested in iPrEx
will have the same effect in womens bodies as they did in the bodies
of the male and transgender study participants. Additional PrEP
trials are already underway, including a study enrolling heterosexual
men and women in Botswana and the UK, one enrolling just heterosexual
women in seven African countries, and one enrolling serodiscordant
couples (couples with one HIV-positive and one HIV-negative member) in
Kenya and Uganda. Studies enrolling injection drug users and
adolescents of all genders are also occurring. Expected to produce
results in 2011-2013, these studies will tell us more about the
gender-based differences (if any) in how the drugs tested in iPrEx
work. But the iPrEx results are certainly cause for optimism that PrEP
may provide women with another HIV prevention tool in the near future.
2. Who will get these PrEP medications now?
Truvada® (a combination of Tenofovir Disoproxil Fumarate or TDF and
Emtricitabine) is the medication tested in the iPrEx trial. In the
short term, this drug will only be legally available to iPrEx study
participants, who will be offered the option to volunteer for the
follow-up open label study. This standard procedure recognizes the
ethical responsibility to allow those who took on the burden of study
participation to be the first to benefit from the study results and it
allows investigators to gather more information about use of the
medication..
The unusual aspect of this process, however, is that Truvada® is
already on the market and regularly prescribed to treat people living
with HIV. Typically, it takes three to five years to get a new drug
into consumers hands after it is proven to be effective. It has to be
reviewed and approved by government regulators, manufacturing of it
has to be scaled up, a supply chain has to be created to get it from
factory to stores, etc. Truvada® is now only approved as a treatment
for HIV and will have to go through a separate regulatory approval to
be marketed for HIV prevention once at least one other study confirms
its efficacy at an acceptable rate. Nevertheless, some consumers can
already access it for prevention from private health care providers.
Physicians in the U.S. and some other countries can, at their
discretion, prescribe drugs for purposes other those for which they
have been approved (a practice usually known as off-label use).
Thus, these drugs are already available as prevention tools to those
able to pay for them privately.
The third option -- and one of which womens health advocates need to
be particularly mindful is that the pill may prevent HIV headlines
could escalate the informal (or black market) sale of Truvada®.
Envision the following: On one hand we have people who read the
headlines and want to take a pill to protect themselves rather than
having to use condoms. But they either dont want to go to a doctor or
cant find one willing to prescribe these drugs for HIV prevention.
On the other hand, we have people living with HIV who are being
prescribed Truvada®. How do HIV-positive individuals who are poor
choose between maintaining the treatment regimen they need to stay
healthy and selling their pills at a high price on the street? This
may be particularly problematic for indigent women living with HIV who
are trying to make ends meet for their families. What about the woman
who brings the pills home only to have her partner or someone else
take them away from her to use himself for prevention or to sell on
the street? This threat of mis-appropriation is one of the major
differences between PrEP and microbicides. Men are foreseeably much
less likely to grab up a woman's microbicidal gel (once we have one)
because they will not see it as something that other men want or that
they can use, themselves.
Informal marketing and non-prescription use of PrEP drugs may also
have serious public health implications. To get these pills prescribed
for prevention, consumers will have to take an HIV test before each
refill to ensure that they are still HIV negative. If you use PrEP
when you are already HIV-positive, you may develop drug resistant
virus. You could pass this resistant strain on to other people and
having it is likely to make it harder to treat your HIV infection on
an on-going basis. Experts warn that epidemiological train wrecks
could occur if access to these drugs used for both prevention and
treatment is not well controlled.
Very little drug resistant virus was detected among participants in
the iPrEx study because they received HIV tests monthly and stopped
using the Truvada® immediately if they tested positive. In real world
use, people obtaining Truvada® without a prescription will likely not
be tested regularly. The longer they, unknowingly, continue to take
the drug after acquiring HIV, the higher the chance that they may
develop drug resistant virus.
Uncontrolled access could result in a rise in the prevalence and
transmission of virus that is resistant to these drugs, resulting in
reduced utility of first-line treatment regimens involving Viread® (an
antiretroviral drug containing TDF) and Truvada® and a subsequent rise
in the death rate. Someone using black market Truvada® occasionally
(rather than daily) or those who sometimes buy counterfeit versions of
Truvada® that contain no active drug may be particularly susceptible
to developing resistant virus if they become HIV positive, are not
tested, and continue to take non-prescription PrEP drugs. At the very
least, we have to anticipate that increased levels of drug resistance
would increase the cost of treating HIV because more second-line
treatments (those able to overcome drug resistant virus) would be
required.
3. How might PrEP work in the real world?
As womens health advocates, there are things we can do to try to
ensure that the iPrEx results lead to good outcomes for women that are
not eclipsed by unintended consequences. Among other things, we must:
Insist that policy makers look at real world issues, not just clinical
trial results:
The CDC is preparing a PrEP implementation plan that will include
public education, guidance for physicians and health care providers
regarding PrEP use, and implementation research. Advocates need to
insist that the implementation research agenda include examination of
the impact of informal marketing and drug sharing on the well-being of
people living with HIV and on public health generally. If evaluators
focus solely on the experience of people with legal access to PrEP
drugs, they may miss effects such as treatment non-adherence due to
drug misappropriation, increases in drug resistant virus levels due to
sporadic use of illegally obtained and/or counterfeit PrEP drugs, and
other consequences indicative of informal marketing and drug sharing
practices.
Call for resistance monitoring systems:
Once approved for use in the U.S., PrEP is only likely to be
prescribed to high-risk people who are demonstrably unable to use
other HIV prevention methods consistently. Nevertheless, we need to
put systems in place now to do baseline assessments of
population-level drug resistance and then monitor the level
periodically so that any effect PrEP has on the prevalence of drug
resistant virus can be tracked. Research has shown that, in places
where anti-retroviral drugs are widely used, between 5 and 15 percent
of new HIV infections transmit drug-resistant virus from one person to
another. We will need an effective evidence base to determine whether
or not use of PrEPformal or informal/off-labelis increasing the
prevalence of HIV that is resistant to PrEP drugs.
Demand stakeholder involvement in setting the PrEP research agenda and roll-out:
As mentioned above, trials showing how PrEP works in womens bodies
are likely to produce results in the next few years. Additional data
are needed to show whether gender-based differences occur in terms of
overall effectiveness and the incidence and severity of side effects
during long term use. Additional trials will also be needed to
determine how use of PrEP drugs affects pregnancy or breastfeeding.
Advocacy will be required to get those trials on the research agenda
sooner rather than later.
Implementation research is also needed to understand the barriers that
keep people from accessing HIV testing and how they can be overcome.
Women who need PrEP because they have no other prevention alternative
when their partners dont use condoms will be unable to get it if they
feel unable or unwilling to get HIV testing.
Most of all, community stakeholders need to play key roles in planning
and delivering highly targeted community education about PrEP. This
is essential to ensuring that women and men in high risk communities
understand about how PrEP works and why it is not a replacement for
condoms. People will need to hear clearly, from those they perceive as
credible, that they endanger their own healthand the communitys
healthif they use PrEP without a prescription or buy it on the
street.
No matter how well PrEP works to prevent HIV in tightly controlled
clinical trials environments, significant stumbling blocks exist to
its effective use in the real world. Unfortunately, these real world
challenges are often set aside as issues that can be addressed once
roll-out of an intervention to the target population has been
achieved. Funders and policymakers often see work to address them
prior to introduction as optional and aspirational, rather than as an
investment that is essential to the interventions success.
We cant let PrEP go the route of condoms and circumcisionbecoming an
HIV prevention tool primarily benefitting men. As we celebrate
evidence of its potential effectiveness, we must also pay close
attention to what next steps are needed to put this new HIV prevention
tool into the hands of the women who need it most.
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