Treatment Is Prevention: ARV Treatment in HPTN-052 Reduces Transmission by at Least 96%: Single Transmission in Treatment Arm Occurred Prior to Viral Suppression
These results add to research that not only correlates viral load with risk of sexual transmission but specifically demonstrates a protective impact with treatment. The two cases of transmission in the early treatment arm (a second was discussed during the presentation) were both detected at the beginning of the study prior to the positive person reaching suppressed viraemia <400 copies/mL.
The fewer clinical endpoints from earlier treatment for the HIV-positive partners in this study are important but were driven by extrapulmonary TB. This clinical difference has significance for people in geographical regions where this study was run, but this aspect of the results was unexpected and has yet to be explained. A more generalisable benefit to people in Western countries is probably the reduced CD4 response in the deferred arm and this needs to be supported by longer follow-up. The ongoing START study will report on whether clinical benefits result from earlier treatment in Western countries.
It would be interesting to model the potential number of transmissions that have already been prevented over the last ten years from the seven million people globally on HAART. Given the financial constraints of access to treatment the additional impact on prevention should be included in future cost: benefit analysis.
The results from HPTN 052 clearly support offering an option for treatment to HIV-positive people who have HIV negative partners. This has been included in UK (BHIVA) guidelines for many years.
When access to treatment is limited with a waiting list using CD4 upper cut-offs to access treatment, those with the most severe medical should clearly be prioritised. However, the majority of the nine million people currently identified by UNAIDS and WHO analyses as requiring but not yet able to access treatment are likely to be undiagnosed. Broadening the CD4 criteria for access to treatment as prevention at higher CD4 counts is unlikely to directly deny access to treatment for more advanced patients.
It was unfortunate that a WHO guideline due to be launched at the IAS meeting, that included the recommendation for treatment people with CD4 counts higher than 350 and who have HIV-negative partners, based on the HPTN 052 study was withdrawn at the last minute.6
Although printed for a launch at the conference there is concern that while the scientific evidence is clear -- and this should be the focus for clinical guidelines -- practical issues on implementation have stalled their release perhaps under pressure from prominent WHO funders. It is difficult to understand how such a useful document that included broad community consultation and approval to the stage of print would have been retracted at such a late stage. WHO say this is due to a need to make "small modifications" and "to review their modeling data they used to inform investment structures". The timeline for these changes are 2-3 months.
This plausibility for intervention from outside the extensive WHO guidelines writing and advisory panels is supported by an article in Science magazine that names the Gates Foundation specifically related to their interest in the latest PrEP results also being included.7
Unless stated otherwise, all references are the Programme and Abstracts of the 16th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 17-20 July 2011, Rome.
Links to external websites are current at time of posting but not maintained.
This article was provided by HIV i-Base. It is a part of the publication HIV Treatment Bulletin. Visit HIV i-Base's website to find out more about their activities, publications and services.
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