The HIV Diagnostics Pipeline
The HIV Diagnostics Pipeline By POLLY CLAYDEN The effectiveness of antiretroviral treatment delivery was traditionally thought to depend on the use of sophisticated diagnostic tests. Earlier this year, important findings from the Development of AntiRetroviral Therapy in Africa (DART) trial, conducted in Zimbabwe and Uganda were published, showing impressive survival rates in people receiving routine clinical monitoring alone. This trial randomized patients to receive either clinical monitoring or laboratory (hematology, biochemistry and CD4) plus clinical monitoring. At five years, 87% and 90% of patients were alive in the clinical and laboratory arms respectively.1 These results were even more impressive as patients in this trial had a median baseline CD4 count of 86 cells/mm3. The DART investigators concluded that ART could be delivered safely with good quality clinical care, allowing treatment delivery to be decentralized. Despite DART results being occasionally misinterpreted to suggest that this argues for no monitoring at all, the investigators also recommended that there is a role for CD4 testing from the second year on ART to guide the switch to a second-line regimen–and clearly to start treatment. They added that this should encourage accelerated development of simpler, cheaper, point-of-care CD4 tests. Furthermore, in an accompanying editorial, Andrew Phillips and Joep van Oosterhout argue that, although the authors suggest that the advantage of measuring viral load on survival may have been modest in this cohort, the reduction of transmission of drug-resistant virus, which will undermine the effectiveness of antiretroviral therapy over the longer term may be another reason to measure it. “Therefore development of cheap robust assays for viral load that can easily be used in rural and urban settings is of the highest priority for researchers.� There are many arguments for the development of affordable point of point-of-care assays. CD4 measurements are essential for knowing when to initiate ART. CD4 counts also guide the use of opportunistic infection prophylaxis. Viral load testing is essential to diagnose HIV-infected infants (see next chapter) and to monitor virological suppression in pregnant women to reduce the risk of mother to child transmission. These tests can be used to monitor adherence early on, and better inform decisions about treatment modifications or switches.3,4
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