Zimislecel is an allogeneic stem cell-derived islet-cell therapy. Data on the safety and efficacy of zimislecel in persons with type 1 diabetes are needed. We conducted a phase 1-2 study of zimislecel in persons with type 1 diabetes. In part A, participants received a half dose of zimislecel (0.4 × 10⁹ cells) as a single infusion into the portal vein, with an option for a second half dose within 2 years. In parts B and C, participants received a full dose of zimislecel (0.8 × 10⁹ cells) as a single infusion. All the participants also received glucocorticoid-free immunosuppressive therapy. The primary end point in part A was safety. The primary end point in part C was freedom from severe hypoglycemic events during days 90 through 365, with a glycated hemoglobin level of less than 7% or a decrease of at least 1 percentage point from baseline in the glycated hemoglobin level at one or more time points between days 180 and 365. Secondary end points in part C included safety and insulin independence between days 180 and 365. Assessment of the primary and secondary end points in part C involved the participants who received the full dose of zimislecel as a single infusion in part B or C. Detection of serum C-peptide during a 4-hour mixed-meal tolerance test was used to assess engraftment and islet function. All the analyses were interim and not prespecified. A total of 14 participants (2 in part A and 12 in parts B and C) completed at least 12 months of follow-up and were included in the analyses. C-peptide was undetectable at baseline in all 14 participants. After zimislecel infusion, all the participants had engraftment and islet function, as evidenced by the detection of C-peptide. Neutropenia was the most common serious adverse event, occurring in 3 participants. Two deaths occurred - one caused by cryptococcal meningitis and one by severe dementia with agitation owing to the progression of preexisting neurocognitive impairment. All 12 participants in parts B and C were free of severe hypoglycemic events and had a glycated hemoglobin level of less than 7%; these participants spent more than 70% of the time in the target glucose range (70 to 180 mg per deciliter). Ten of the 12 participants (83%) had insulin independence and were not using exogenous insulin at day 365. The results of this small, short-term study involving persons with type 1 diabetes support the hypothesis that zimislecel can restore physiologic islet function, warranting further clinical investigation. (Funded by Vertex Pharmaceuticals; VX-880-101 FORWARD ClinicalTrials.gov number, NCT04786262.).

Background: Recent studies suggest that immunotherapy using T regulatory cells (Tregs) prolongs remission in type 1 diabetes (T1DM). Here, we report factors that possibly affect the efficacy of this treatment. Methods: The metabolic and immune background of 12 children with recently diagnosed T1DM, as well as that of untreated subjects, during a 2-year follow-up is presented. Patients were treated with up to 30 × 10⁶/kg b.w. of autologous expanded CD3⁺CD4⁺CD25^highCD127⁻ Tregs. Results: The disease progressed and all patients were insulin-dependent 2 years after inclusion. The β-cell function measured by c-peptide levels and the use of insulin were the best preserved in patients treated with two doses of Tregs (3/6 in remission), less so after one dose (1/6 in remission) and the worst in untreated controls (no remissions). Increased levels of Tregs could be seen in peripheral blood after their adoptive transfer together with the shift from naïve CD62L⁺CD45RA⁺ to memory CD62L⁺CD45RA⁻ Tregs. Increasing serum levels of proinflammatory cytokines were found: IL6 increased in all subjects, while IL1 and TNFα increased only in untreated group. Therapeutic Tregs were dependent on IL2, and their survival could be improved by other lymphocytes. Conclusions: The disease progression was associated with changing proportions of naïve and memory Tregs and slowly increasing proinflammatory activity, which was only partially controlled by the administered Tregs. The therapeutic cells were highly dependent on IL2. We conclude that the therapy should be administered at the earliest to protect the highest possible mass of islets and also to utilize the preserved content of Tregs in the earlier phases of T1DM. Trial registrationhttp://www.controlled-trials.com/ISRCTN06128462; registered retrospectively

Selection of an optimal donor pancreas is the first key task for successful islet isolation. We conducted a retrospective multicenter study in 11 centers in North America to develop an islet donor scoring system using donor variables. The data set consisting of 1,056 deceased donors was used for development of a scoring system to predict islet isolation success (defined as postpurification islet yield >400,000 islet equivalents). With the aid of univariate logistic regression analyses, we developed the North American Islet Donor Score (NAIDS) ranging from 0 to 100 points. The c index in the development cohort was 0.73 (95% confidence interval 0.70–0.76). The success rate increased proportionally as the NAIDS increased, from 6.8% success in the NAIDS < 50 points to 53.7% success in the NAIDS ≥ 80 points. We further validated the NAIDS using a separate set of data consisting of 179 islet isolations. A comparable outcome of the NAIDS was observed in the validation cohort. The NAIDS may be a useful tool for donor pancreas selection in clinical practice. Apart from its utility in clinical decision making, the NAIDS may also be used in a research setting as a standardized measurement of pancreas quality.

Islet allotransplantation in the United States (US) is facing an imminent demise. Despite nearly three decades of progress in the field, an archaic regulatory framework has stymied US clinical practice. Current regulations do not reflect the state‐of‐the‐art in clinical or technical practices. In the US, islets are considered biologic drugs and “more than minimally manipulated” human cell and tissue products (HCT/Ps). In contrast, across the world, human islets are appropriately defined as “minimally manipulated tissue” and not regulated as a drug, which has led to islet allotransplantation (allo‐ITx) becoming a standard‐of‐care procedure for selected patients with type 1 diabetes mellitus. This regulatory distinction impedes patient access to islets for transplantation in the US. As a result only 11 patients underwent allo‐ITx in the US between 2016 and 2019, and all as investigational procedures in the settings of a clinical trials. Herein, we describe the current regulations pertaining to islet transplantation in the United States. We explore the progress which has been made in the field and demonstrate why the regulatory framework must be updated to both better reflect our current clinical practice and to deal with upcoming challenges. We propose specific updates to current regulations which are required for the renaissance of ethical, safe, effective, and affordable allo‐ITx in the United States.