When Does CD4 Cell Count Plateau?
Evidence from Patients Treated with Lopinavir/ritonavir for up to 7 Years It is unclear how long subjects who receive long-term antiretroviral therapy can maintain continued CD4 cell count increases. Previous studies have generally suggested a plateau 3-4 years after treatment initiation. Researchers from Abbott Laboratories analyzed CD4 cell count changes from baseline in 100 antiretroviral-naive subjects treated with lopinavir/ritonavir (Kaletra) + d4T (stavudine; Zerit) + 3TC (lamivudine; Epivir) for up to 7 years (360 weeks). Results were presented at the 46th Interscience Conference on Antimicrobial Agents and Chemotherapy taking place this week in San Francisco. The investigators used nonlinear regression to fit a segmented model (by baseline CD4 cell count strata) consisting of a quadratic model followed by a plateau. Results Mean baseline CD4 cell counts were 485, 129, and 24 cells/mm3, respectively, for subjects with baseline CD4 counts greater than 200 cells/mm3 (n = 64), 50-
