Tenofovir DF (Disoproxil Fumarate) in Combination With Emtricitabine in HIV-1 Patients

Inclusion Criteria: Patients must meet all of the following inclusion criteria to be eligible for participation in the study. * HIV-1 infection * Either antiretroviral therapy-naive requiring antiretroviral treatment with HIV-1 RNA greater than 400 copies/mL or antiretroviral therapy-experienced on a stable antiretroviral regimen for at least 3 mos. with HIV-1 RNA less than or equal to 50 copies/mL at screening. * No active opportunistic infection within 45 days prior to baseline. * Able to understand and sign the informed consent form and comply with the study. * Stable renal impairment within the four defined groups for at least 3 mos., based on creatinine clearance (Cockcroft-Gault method). Exclusion Criteria: Patients who meet any of the following are not to be enrolled in this study. * Women who are pregnant or breastfeeding * Fanconi syndrome or multiple myeloma, tertiary hyperparathyroidism, malignancy (with the exception of basocellular carcinoma) or myeloproliferative disorder. * Women of childbearing potential who are unwilling to use an effective contraceptive method during the study * Contraindications to tenofovir DF, emtricitabine or efavirenz * Undergoing treatment for tuberculosis * Using atazanavir * Prior history of mutation M184V, K65R or T69 insertion * Z-score on pre-baseline DEXA scan less than -2.5 * The following laboratory values within 30 days prior to study entry: \*absolute neutrophil count (ANC) less than 750/mm3, \*hemoglobin less than 9.0 g/dL, \*platelet count less than 50,000/mm3, \*AST (SGOT) or ALT (SGPT) less than 5 x ULN and \*CD4 cell count less than 100/mm3. * Use of nephrotoxic agents or competitors with renal excretions, including aminoglycoside antibiotics, intravenous amphotericin B, cidofovir, cisplatin, foscarnet, intravenous pentamidine, probenecid or other agents with significant nephrotoxic potential * Clinically significant cardiac, pulmonary or gastrointestinal disorder * Alcohol or drug abuse that could hinder compliance with the study