Abacavir-based therapy does not affect biological mechanisms associated with cardiovascular dysfunction

Objective: To assess the effects of initiating abacavir-containing therapy on plasma lipids and cardiovascular biomarkers. Design: Sub-study of the BICOMBO study in which participants were randomized to switch their nucleoside backbone to either abacavir/lamivudine or tenofovir/emtricitabine. Methods: We assessed 48-week changes in fasting lipids and several biomarkers including serum high-sensitivity C-reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), osteoprotegerin, interleukin (IL)-6, IL-10, tumor necrosis factor alpha (TNF-alpha), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), selectin E and P, adiponectin, insulin, and D-dimer in otherwise healthy, virologically suppressed HIV-infected patients randomly switched to abacavir/ lamivudine or tenofovir/emtricitabine with no history of cardiovascular disease, no prior abacavir or tenofovir use, and no virological failure or AIDS during follow-up. Results: Eighty (46 abacavir/lamivudine and 34 tenofovir/emtricitabine) patients were included. Baseline characteristics were similar between groups and between patients in the sub-study vs. those not. There were no significant differences in baseline lipids and markers between groups. Although total (6.5 vs. -6.7%, P < 0.0001) and low-density lipoprotein (LDL) (8.6 vs. -9.1%, P=0.004) cholesterol increased significantly in the abacavir/lamivudine group relative to the tenofovir/emtricitabine group, we found no significant changes in the biomarkers: CRP (-3.9 vs. 0.0%), MCP-1 (5.9 vs. 4.0%), osteoprotegerin (5.1 vs. -2.8%), IL-6 (0.0 vs. 0.0%), IL-10 (0.0 vs. 0.0%), TNF-alpha (0.0 vs. 0.0%), ICAM-1 (6.6 vs. 5.2%), VCAM-1 (0.02 vs. -0.01 %), selectin E (-0.4 vs. 7.8%), selectin P (4.6 vs. 12.6%), insulin (-2.5 vs. 8.8%), adiponectin (-2.2 vs. 15.4%), and D-dimer (0.0 vs. 0.0%) (P≥0.12 for all comparisons). Conclusion: Abacavir/lamivudine increased total and LDL cholesterol compared with tenofovir/emtricitabine, but it did not cause inflammation, endothelial dysfunction, insulin resistance, or hypercoagulability in virologically suppressed HIV-infected patients.