Raltegravir and Atazanavir Dosing Strategy Study

Inclusion Criteria: * aged ≥ 18 years with laboratory evidence of HIV-1 infection * currently receiving 3 or more unchanged antiretroviral agents including atazanavir (with or without ritonavir boosting) for at least 24 weeks prior to study entry * plasma HIV RNA less than 50 copies/mL for at least 24 weeks prior to study entry * provide written, informed consent. Exclusion Criteria : * prior clinical/virological failure on a PI-containing regimen * no clinical history of primary HIV-1 protease mutations identified in local baseline genotypic analysis of HIV with interpretation using current IAS-USA Drug Resistance Mutations in HIV-1 * women: pregnant, breastfeeding, or not willing to use adequate contraception (including barrier contraception) if of child-bearing potential * laboratory abnormalities at screening: * absolute neutrophil count (ANC) \< 750 cells/mL * haemoglobin less than 8.5 g/dL * platelet count less than 50 000 cells/mL * AST, ALT \> 5 times the upper limit of normal * serum bilirubin \> 5 times the upper limit of normal * chronic active hepatitis B infection defined by presence of serum viral hepatitis B surface antigen (HBsAg) or HBV DNA-positive * any malabsorption syndrome likely to affect drug absorption * concurrent therapy with human growth hormone or other immunomodulatory agents * concomitant medication contraindicated for use with either atazanavir or raltegravir therapy * any inter-current illness requiring hospitalisation * current excessive alcohol or illicit substance use * unlikely to be able to remain in follow-up for the protocol-defined period.