This study is designed to compare the efficacy and safety of simplifying therapy from a regimen of atazanavir (ATV) + ritonavir (RTV) + tenofovir/emtricitabine (TDF/FTC) to a regimen of ATV + abacavir sulfate/lamivudine (ABC/3TC) without RTV in virologically suppressed, HIV-1 infected, HLA-B*5701 negative subjects for 48 weeks.