ABSTRACT
Studies evaluating combinations of antiretroviral drugs introduced the new treatment paradigm for HIV infection – the suppression of plasma HIV RNA below detectable levels. This strategy has become the standard for patient management and the criterion by which new drugs and new drug combinations are evaluated. A significant minority of patients initiating antiretroviral therapy with wild type virus at baseline fail to suppress HIV RNA to undetectable levels. An initial study proposing undetectability as a treatment endpoint was the Merck 035 study which described an 85% rate of undetectability at 1 year on zidovudine/lamivudine/indinavir and a rate of 78% after 100 weeks of such treatment. There is histological evidence of residual replication in lymphoid tissue of patients with undetectable HIV RNA. Nucleic acid extracts of lymph node biopsies from patients with undetectable HIV RNA after 6–12 months of suppressive treatment showed 4 logio reductions.
