CROI 2012: Changing Winds in HIV/AIDS Research
Prevention Revolution/Biomedical Prevention in Action/Treatment as Prevention
Pre-exposure prophylaxis (PrEP) is the utilization of antiviral drugs by HIV negative people in order to prevent HIV infection. This topic has been controversial. In recent studies the effectiveness of this intervention was between 42 to 76%. One study was halted early for failure to produce any protective effect (FEM-PrEP).
One of the pivotal studies was Partner PrEP, which enrolled 4,758 sero-discordant couples (one positive and the other negative); the HIV negative was assigned by chance to receive one of two regimens -- Tenofovir alone or Tenofovir/Emtricitabine (Truvada) or placebo. Overall PrEP decreased new infections by 70%. One presentation at CROI 2012 was dedicated to present the analysis of people who became infected during the study Partners PrEP, while taking ART drugs. Twenty-nine people were infected in the two PrEP active drug arms. Interestingly, only 35% of people taking Tenofovir alone had detectable drug levels in blood. In the Truvada group only 25% has detectable drug levels in blood. It is important to acknowledge that a sub analysis found that new infections were reduced by 86% and 90% in the Tenofovir and Truvada arms respectively.
IPrEx is another study on PrEP targeting men who have sex with men (MSM) and transgender women. In this multinational study, 2,499 people participated and were randomly assigned to Truvada or placebo once daily. These people were tested every 12 weeks. There were 132 new HIV infections, 84 in the placebo arm and 48 in the Truvada PrEP arm. These results indicated a 42% effectiveness rate in an overall intent-to-treat analysis. However the effectiveness rate was 92% among those with detectable drug levels in their blood. Further studies identified how frequently Tenofovir should be administered in order to have a protective effect. For instance, taking Tenofovir seven days a week confers a 99% reduction of HIV infection.
PrEP is still controversial despite of its promising results. Adherence is going to become a major obstacle to overcome in order to achieve acceptable levels of protection. Also, recent studies have identified that a large proportion of people living with HIV who needs antiretroviral therapy do not access to these medications in the United States. According to NASTAD there are over 4,000 people on waiting lists for AIDS drug assistance programs (ADAP). The situation is more precarious around the world. In general, health disparities are a major issue and PrEP will make these disparities deeper. There is a lot of work to done before the PrEP benefits will become a reality.
For the last five years, the term "community viral load" (the average viral load of people known to be HIV+ in a community) became a buzz word in the arena of intervention that seeks the control of the HIV epidemic. During CROI 2012, data from San Francisco Early HIV Treatment Policy was presented. This policy offers ART to everyone who tests positive for HIV regardless of CD4 cell count. Elvin Geng from UCSF presented the findings from a study of clinical practice and patient outcomes since the new policy took effect in 2010. The main finding is that the likelihood of HIV suppression more than doubled after the adoption of this new policy, with rapid suppression and less rebound of viral load in comparison with those who started with lower CD4 counts.
However, this universal early treatment policy has the potential to increase the depth of disparities between those who receive the current standard of care and those who participate in the new policy. For instance, people who started ART with CD4 cells counts >500 were significantly more likely to be white MSM and diagnosed by private clinicians, and less likely to be at the poverty level. Evidence of the benefits of this intervention exposes a new potential inequality for populations already disproportionately affected by HIV, including youth, African Americans, the poor, and those diagnosed at facilities other than private providers. According to the authors, unless these gaps are closed through specific efforts for earlier diagnosis, care, and ART initiation, we may observe increasing health and survival disparities among people living with HIV.
We are facing incredible times with the work on HIV/AIDS. Although we are seeing remarkable achievements in biomedical prevention (treatment as prevention) and the search for the cure (human viral eradication), we are also facing severe challenges due to financial constraints and changes in the political landscape of this country. The return of the International AIDS Conference (IAC) to American territory will offer the opportunity for HIV activists to reignite commitment and passion in the work of HIV/AIDS and secure the financial resources to confront our new challenges. This is the right time to become involved and participate in public forums, sign petitions, and contact your elected officials. Also, you can join Being Alive and be part of its advocacy initiatives.
This article was provided by Being Alive. It is a part of the publication Being Alive Newsletter. Visit Being Alive's website to find out more about their activities, publications and services.
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