Study Of Investigational Regimen Combining FDA Approved HIV Drugs In HIV Subjects Experiencing Early Virologic Failure

Inclusion Criteria: * Currently on an initial HAART (highly active antiretroviral therapy) regimen of 3TC/ZDV or 3TC/d4T and a PI (protease inhibitor) -boosted or unboosted- or NNRTI (non-nucleoside reverse transcriptase inhibitor). * Plasma HIV - 1 RNA was \<400 copies/ml on at least 2 documented occasions prior to viral rebound. * Have a plasma HIV - 1 RNA value \>400 copies/ml and \<10,000 copies/ml on 2 documented successive occasions (including screen) separated by at least 2 weeks. * A CD4+ lymphocyte count less than or equal to 100. Exclusion Criteria: * Have not taken Abacavir (ZIAGEN or TRIZIVIR) or tenofovir (VIREAD) previously. * Have not had an AIDS defining illness within 30 days of screen. * Pregnant or breast-feeding. * Specified viral genotypes upon screening. * And other inclusion or exclusion criteria to be evaluated by the physician.