Precision Administration of Anti-thymocyte Globulin With or Without Verapamil

T cell directed therapy, anti-thymocyte globulin (ATG), in low doses, has been shown to lower HbA1c and preserve endogenous insulin production (measured by C-peptide) in individuals with recently diagnosed type 1 diabetes (T1D). However, not all individuals who received ATG responded to the therapy (i.e., non-responders). Additionally, use of ATG alone does not address inherent beta cell stress. A calcium channel blocker, verapamil, has demonstrated C-peptide preservation in newly diagnosed T1D. Investigators will identify those mostly likely to respond to ATG using an ex vivo predictive biomarker of response to ATG. In addition, Investigators will use sequential therapies to increase efficacy (ATG followed by verapamil) and explore synergistic mechanisms. This will be assessing with in depth immunophenotyping and quantify biomarkers of beta cell stress, cell death, and abnormal prohormone processing. Finally, novel clinical trial endpoints will be assessed for their ability to predict treatment efficacy earlier than the standard endpoint at 1 year.