Highlights from the AIDS conferences

In the past months there were two important AIDS conferences: the 5th South African AIDS conference which was held from 7-10 June 2011 in Durban and the 6th IAS conference on HIV pathogenesis, treatment & prevention which was held from 17-20 July 2011 in Rome. Here I highlight some of the most important study findings that were presented at these conferences.

In May 2011 the HPTN 052 randomised controlled trial (RCT) of when to start HIV-positive people on ART, conducted in nine countries including South Africa, was terminated four years ahead of schedule because the evidence of impacts was so overwhelming that it became unethical to refuse early treatment to the control arm (1). The study showed that if an HIV-positive person adheres to an effective ARV therapy regiment, the risk of transmitting the virus to their uninfected sexual partner can be reduced by 96% and the incidence of TB by 82%. While there were also fewer deaths among those that started ART immediately the reduction was not statistically significant. Only people living with HIV not eligible for treatment for their own health according to latest WHO guidelines (CD4+ cell counts between 350 and 550) were enrolled in the study. One of Epi Results clients, SACEMA – the South African Centre for Epidemiological Modelling and Analysis – has already since 2009 been promoting the idea of annual HIV testing and immediate initiation of HAART as a way of massively reducing incidence in high prevalence settings to the extent that we could feasibly see an end to the HIV pandemic by 2050 (2).

Another way to apply Treatment as Prevention was highlighted last year when a vaginal gel containing an antiretroviral called tenofovir (TDF) turned out to be able to protect women from HIV (3). It showed that a TDF-based microbicide gel is 39% effective in preventing HIV transmission in women. The level of protection was more than 54% for women who used the gel regularly. The CAPRISA results were the first to establish the efficacy of a microbicide gel, after many years of setbacks in microbicide efficacy trials. A number of trials are planned to support this first trial and of these is the Follow-on African Consortium for Tenofovir Studies (FACTS) 001 trial (4). Another large trial currently underway in a number of African countries will compare the efficacy of TDF gel with TDF tablets, as well as comparing TDF with another ARV called Truvada (the tablet form of TDF, in combination with emtricitabine (FTC)) (5). The much anticipated Preexposure Prophylaxis (PrEP) Initiative (abbreviated to “iPrEx”), announced in November 2010, showed that oral PrEP (in the form of TDF/FTC) reduces risk of infection by 44% among HIV-negative high-risk men who have sex with men (MSM). However, the FEM-PrEP trial interim results showed that Truvada does not have a protective effect in women, although preliminary results from the Partners PrEP trial and the TDF2 study did show an effect (reduction of the risk of transmission by between 62% and 78%) (7)).

References:

1. HIV Prevention Trials Network. Initiation of Antiretroviral Treatment Protects Uninfected Sexual Partners from HIV Infection (HPTN Study 052). http://www.hptn.org/web%20documents/PressReleases/HPTN052PressReleaseFINAL5_12_118am.pdf Accessed 15 August 2011.
2. Granich RM, Gilks CF, Dye C, De Cock KM, Williams BG. Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. Lancet. 2009; 373(9657): 48-57. Link to article
3. Karim QA, Karim SS, Frohlich JA, et. al. Effectiveness and Safety of Tenofovir Gel, an Antiretroviral Microbicide, for the Prevention of HIV Infection in Women. Science. 2010;329(5996):1168-74. Link to article
4. TimesLive. State to run trials of anti-HIV gel. http://www.timeslive.co.za/specialreports/hivaids/2011/06/14/state-to-run-trials-of-anti-hiv-gel Accessed 15 August 2011.
5. Microbicide Trials Network. HIV Prevention Trial Milestone: VOICE Study Completes Enrollment of 5,000 Women. http://www.mtnstopshiv.org/node/3413 Accessed 15 August 2011.
6. NAM AIDSMAP. Two major studies show that HIV drugs prevent infection. http://www.aidsmap.com/Two-major-studies-show-that-HIV-drugs-prevent-infection/page/1870585/ Accessed 15 August 2011.