HIV-1 Reverse Transcriptase and Protease Resistance Mutations Selected during 16–72 Weeks of Therapy in Isolates from Antiretroviral Therapy-Experienced Patients Receiving Abacavir/Efavirenz/Amprenavir in the CNA2007 Study

Abstract

Prior NNRTI and NRTI therapy influences the pathway of resistance to efavirenz. In this study, the prevalence of mutations selected by efavirenz were different from those described in less ART-experienced patients. Baseline Y181C was associated with the development of mutations at position 190, but not L100I or K103N. In this patient population, abacavir with efavirenz preferentially selected for L74V but not for thymidine analogue mutations. M184V was rarely selected and was maintained in only 77% of patients who did not add lamivudine or didanosine. Finally, amprenavir-specific mutations were selected in the background of other primary protease inhibitor mutations, confirming the distinct resistance profile of amprenavir.