Impact of Metformin on Immuno-virologic Parameters in HIV

Non-diabetic, aviremic HIV-infected individuals on antiretroviral therapy (ART) will be randomized to metformin therapy or to observation for 72 weeks. Primary objective is to assess change over 72 weeks in CD4 T cell negative checkpoint receptors (PD-1 and TIGIT). As secondary objectives the study will look at 72 week change in other immuno-virologic parameters (CD8 T cell negative checkpoint receptors, plasma indoleamine 2,3-dioxygenase (IDO) levels and CD4 T cell and monocyte intracellular HIV DNA and HIV RNA. The study will also explore the 72 week impact of metformin on change in carotid intima-media thickness (cIMT) as a surrogate marker of atherosclerosis, on neuropsychological (NP) performance, strength, and change in body composition.