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The iPrEx Results: Lifting Hopes, Raising Questions

Summer/Fall 2010

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Other PrEP efficacy trials are underway around the world (see table, below). Additional studies designed to assess the safety and acceptability of oral tenofovir, oral tenofovir/emtricitabine (Truvada) and vaginally applied tenofovir gel as PrEP are also ongoing in diverse populations, including female sex workers and young men who have sex with men. These studies are testing different methods for delivering PrEP drugs (such as vaginal or rectal application), as well as intermittent dosing (twice weekly and after sex); results are expected beginning in early 2011. The ultimate goal of all of these studies is to develop safe, effective and feasible strategies for HIV prevention that will have the greatest public health impact globally.

Ongoing PrEP Efficacy Trials
Trial and InterventionLocation(s)Study PopulationResults Expected
Bangkok Tenofovir Study
Daily oral tenofovir
ThailandInjecting drug usersEarly 2012
iPrEx extension study
Daily oral Truvada
Brazil, Ecuador, Peru, South Africa, Thailand, United StatesMen who have sex with men (including male-to-female transgenders)Mid- to late 2012
Partners PrEP
Daily oral tenofovir; daily oral Truvada
Kenya, UgandaSerodiscordant heterosexual couplesEarly 2013
Daily oral tenofovir; daily oral Truvada; daily topical tenofovir gel
South Africa, Uganda, Zambia, ZimbabweWomenEarly 2013
Daily oral Truvada
Kenya, South Africa, Tanzania, ZimbabweWomenMid- to late 2013

But feasibility must be tested outside the rarified context of controlled research studies. That is why a number of organizations are looking to develop demonstration projects in places like San Francisco, where the iPrEx study findings are particularly relevant because of the disproportionate impact of HIV on gay men. These projects would help determine the best strategies for delivering PrEP, maximizing adherence to the PrEP regimen and assessing the cost-effectiveness of this approach. A qualitative component of these projects would also tell us how individuals do or do not incorporate a new practice (daily or intermittent pill-taking) into their lives and the meanings they bring to that process, and how this influences the effectiveness of PrEP at an individual and community level.

Meanwhile, it is likely that some people will begin asking their health care providers whether they are candidates for taking PrEP based on the iPrEx study results and their sense of their own risk for HIV infection (for example, if they are HIV negative and in a "serodiscordant" partnership with someone who has HIV). The Centers for Disease Control and Prevention (CDC) plans to provide a guidance document to help health care providers make sound clinical decisions with their clients on a case-by-case basis. However, it is currently the consensus of the public heath community that no one should "try this at home" at this point, and that all sexually active people should be advised to continue using condoms for prevention of HIV and other sexually transmitted infections, since condoms remain the most effective tool we have.

The "standard of prevention" for any biomedical trial of an HIV prevention strategy includes counseling about HIV risk and safer sex, testing and treatment for any sexually transmitted infections and access to free condoms.

While this comprehensive HIV prevention package is ethically necessary, it does complicate the interpretation of study results. Researchers may have difficulty determining how much of a reduction in HIV infections was due to the study product and how much was a result of counseling, condom access, etc.

For an in-depth look at this and other quandaries in prevention research, see "Confronting the 'Evidence' in Evidence-Based HIV Prevention: Current Scientific and Political Challenges" in the Summer 2008 issue of BETA.

On the policy and advocacy front, much attention is focused on issues of pricing and availability of PrEP. In the U.S., the annual cost of Truvada when purchased at market rate is about $12,000 to $14,000 per individual. Some countries that have negotiated agreements with Truvada's developer, Gilead Sciences, are able to produce generic versions at a much lower cost, but this is not the case in the U.S. Moreover, the pills are not the only things that come with a price tag; to be an effective HIV prevention strategy, PrEP must be accompanied by regular HIV testing, monitoring for side effects and adherence counseling.


At a time when many HIV positive people in the U.S. and globally still lack access to lifesaving antiretroviral treatment, many people wonder whether it is ethical to provide these same drugs to HIV negative people who have other HIV prevention options. Some also worry that the costs associated with providing PrEP will threaten access to HIV treatment through public programs, such as the AIDS Drug Assistance Program (ADAP), whose funding already is tenuous.

Most of us engaged in AIDS advocacy do not believe that HIV prevention and HIV treatment should be pitted against each other. The best way to ensure that all HIV positive people have access to optimal care and treatment is to reduce the number of people who become infected in the first place. As more HIV positive people around the world survive into midlife and older age because of better and more tolerable antiretroviral therapy, the costs attendant with their care and treatment -- including treatment for comorbidities such as cancer and heart, liver and bone disease -- are becoming insurmountable. Funds for HIV/AIDS treatment and care will go further if fewer people acquire the virus.

We also must be sure that PrEP does not become something only available to people who can afford it, thereby heightening class-associated disparities that already exist in HIV epidemics and in health care systems in the U.S. and elsewhere. This means we must advocate for reduced drug prices for both HIV prevention (PrEP) and HIV treatment, and for equitable health care delivery systems.

Finally, we must ensure that advances in science, like PrEP, continue to happen, by advocating for a robust research enterprise, particularly at the National Institutes of Health (NIH), whose initial funding made the iPrEx study possible. Most other promising HIV prevention studies -- biomedical, behavioral and social -- also depend on support from the NIH, whose budget is currently under threat in these tight economic times.

But this is no time to cut research funding. The recent development of the first U.S. National HIV/AIDS Strategy, whose three main goals are reducing new HIV infections, ensuring access to care and treatment for all HIV positive people, and reducing HIV-associated health disparities, makes clear the need to identify the most effective and efficient strategies to target limited funds. Research is essential to identifying and optimizing those strategies, and to determining whether PrEP is one of them.

efficacy: the capacity of a drug or other intervention to produce a desired effect under ideal research conditions, such as in a controlled trial.

effectiveness: the capacity to produce a desired effect under "real world" conditions, such as in a given community or population.

Judith D. Auerbach, Ph.D., is Vice President of Research & Evaluation at San Francisco AIDS Foundation.

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This article was provided by San Francisco AIDS Foundation. It is a part of the publication Bulletin of Experimental Treatments for AIDS. Visit San Francisco AIDS Foundation's Web site to find out more about their activities, publications and services.
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