HIV-1 induction-maintenance at the lymph node level: the "Apollo-97" Study

To assess the effects of five-drug combination therapy on HIV-1 load in lymph nodes and subsequent maintenance with four and three drugs.

Ten pharmacotherapeutically naive patients received a combination of zidovudine, lamivudine, didanosine, ritonavir, and saquinavir for 24 weeks, then zidovudine, lamivudine, didanosine, and saquinavir for the next 24 weeks, and finally zidovudine, lamivudine, and saquinavir for the last 24 weeks. HIV-1 RNA in lymph nodes was measured using quantitative polymerase chain reaction (PCR) at baseline, after 12, 24, 48, and 78 weeks. Plasma HIV-1 RNA, proviral DNA in peripheral blood mononuclear cells (PBMCs), circulating lymphocyte subsets, and protease inhibitor levels in blood were also regularly measured. Genotypic resistance was assessed in the different compartments in 2 patients who were failed by therapy.

HIV-1 RNA decreased in lymph nodes in 9 patients and was stable in 1 despite initial control of plasma replication <20 copies/ml in each patient. Lymph node levels rebounded in 1 patient at week 72 as a result of lack of adherence and remained stable in the 8 others despite maintenance regimens. This represents a mean drop of -3.17 log in lymph nodes for the 8 patients maintaining undetectable viremia at 72 weeks. In the patient with stable lymph node viral RNA, selection of the M184V mutation was demonstrated at this level before detection in plasma and low blood saquinavir levels were found throughout the study. Continuous improvements in immune parameters were observed in all cases, although PBMC proviral DNA levels either showed a continuous decrease or stabilized to a plateau.

More complex regimens do not perform better in lymph nodes than classic triple therapy. The persistence of HIV-1 RNA in lymph nodes could be related with cellular resistance mechanisms rather than an insufficient potency of the regimens.