Delaying a treatment switch in antiretroviral-treated HIV type 1-infected patients with detectable drug-resistant viremia does not have a profound effect on immune parameters: AIDS Clinical Trials Group Study A5115

Some patients are unable to achieve and maintain an undetectable plasma HIV-1 RNA level with combination antiretroviral therapy (ART) and are therefore maintained on a partially suppressive regimen. To determine the immune consequences of continuing ART despite persistent viremia, we randomized 47 ART-treated individuals with low to moderate plasma HIV-1 RNA levels (200-9999 copies/ml) to either an immediate switch in therapy or a delayed switch (when plasma HIV-1 RNA became ≥10,000 copies/ml). After 48 weeks of follow-up, naive and memory CD4⁺ T cell percents were comparable in the two groups. The proportion of subjects with a lymphocyte proliferative response to Candida, Mycobacterium avium- intracellulare complex, or HIV-gag was also not significantly different at week 48. Delaying a treatment switch in patients with partial virologic suppression and stable CD4⁺ T cells does not have profound effects on immune parameters.