240-OR: Islet Allotransplantation into Prevascularized Sernova Cell Pouch—Early Results from the University of Chicago

Each of 6 patients with T1DM and problematic hypoglycemia received 2 islet transplants into pre-implanted Sernova Cell Pouches (SCPs). Each procedure involved transplantation of islets into two 8-channel SCPs and one mini sentinel SCP. SCP implants and the combination of SCP with human cadaveric islets are both well tolerated with durations exceeding 3 years. Detectable islet function (≥0.3ng/ml peak serum c-peptide in mixed meal tolerance test) was achieved in 4 patients following islet transplant to SCP. It was correlated with transplanted islet mass of 300k-500k IEQ per procedure. Transplantation of islet mass <300k IEQ did not lead to detectable c-peptide secretion. C-peptide was detectable for periods ranging from days up to 12 months after the procedure. Three patients with suboptimal levels of immunosuppression due to non-compliance experienced antibody mediated rejection based on de novo donor specific antibodies (DSAs). One patient with DSAs had detectable stimulated c-peptide at 90 days post-transplant. Histological assessment of sentinel SCPs retrieved ≥90 days post-transplant revealed surviving functional islets within vascularized SCP channels via positive immunofluorescence staining of insulin, c-peptide, glucagon and somatostatin in 5 of 6 patients. Five patients received supplemental intraportal islet transplants (IPITx) and all of them remain insulin independent (>2.5Y, >1Y, 10M, 2M, 1M). The sixth patient is awaiting an IPITx in the coming months as per protocol. Safety and dose-response observations from the first cohort of 6 patients led to the implementation of 10-channel SCPs with 50% greater transplant capacity than the 8-channel configuration in a second study cohort. Two additional patients were recently implanted with 10-channel SCPs and are currently awaiting their first islet transplantation.