The relation between treatment outcome and efavirenz, atazanavir or lopinavir exposure in the NORTHIV trial of treatment-naïve HIV-1 infected patients.

Purpose: The relation between treatment outcome and trough plasma concentrations of efavirenz (EFV), atazanavir (ATV) and lopinavir (LPV) was studied in a pharmacokinetic/pharmacodynamic substudy of the NORTHIV trial-a randomised phase IV efficacy trial comparing antiretroviral-naïve human immunodeficiency virus-1-infected patients treated with (1) EFV + 2 nucleoside reverse transcriptase inhibitors (2NRTI) once daily, (2) ritonavir-boosted ATV + 2NRTI once daily or (3) ritonavir-boosted LPV + 2NRTI twice daily. The findings were related to the generally cited minimum effective concentration levels for the respective drugs (EFV 1,000 ng/ml, ATV 150 ng/ml, LPV 1,000 ng/ml). The relation between atazanavir-induced hyperbilirubinemia and virological efficacy was also studied.