We designed the clinical trial as a single-arm, phase 1-2 trial conducted in two transplant centers (San Raffaele Scientific Institute, Milan, Italy; Cell Isolation and Transplantation Center, University of Geneva, Geneva, Switzerland) which used a common protocol for islet preparation, post-transplantation patient management and data collection. The trial is exploratory in nature and the target enrollment is 10 patients. The recruitment is competitive between the two centers and each patient is to receive at least 10,000 IE/kg. Up to three islet infusions are allowed per patients until insulin independence is reached, provided that partial islet function (i.e., fasting C-peptide ≥0.3 ng/mL) is maintained between infusions. We planned an individual follow-up of 3 years after the last islet infusion.