Figure 2.

Human immunodeficiency virus type 1 (HIV-1) cumulative amino acid changes over time to virologic failure. Each participant with virologic failure is represented by a line from (0,0) to time of virologic failure on the horizontal axis and HIV-1–weighted cumulative amino acid changes on the vertical axis, with mixture changes assigned weight = 0.5 change. A, Among participants with virologic failure, lower pretreatment CD4 count (cells/μL) was associated with more HIV-1 amino acid changes. B, Many of the HIV-1 amino acid changes occurred within participants with virologic failure who had major resistance mutations present prior to treatment or emergent at failure, particularly with efavirenz (EFV). Abbreviations: 3TC, lamivudine; ABC, abacavir; ATV/rtv, atazanavir/ritonavir; FTC, emtricitabine; TDF. tenofovir DF.