Long-term porcine islet graft survival in diabetic non-human primates treated with clinically available immunosuppressants

Background: Although pancreatic islet transplantation is becoming an effective therapeutic option for patients with type 1 diabetes (T1D) who suffer from a substantially impaired awareness of hypoglycemia, its application is limited due to the lack of donors. Thus, pig-to-human islet xenotransplantation has been regarded as a promising alternative due to the unlimited number of “donor organs.” Long-term xenogeneic islet graft survival in pig-to-non-human primate (NHP) models has mainly been achieved by administering the anti-CD154 mAb-based immunosuppressant regimen. Since the anti-CD154 mAb treatment has been associated with unexpected fatal thromboembolic complications in clinical trials, the establishment of a new immunosuppressant regimen that is able to be directly applied in clinical trials is an urgent need. Methods: We assessed an immunosuppressant regimen composed of clinically available agents at porcine islet transplantation in consecutive diabetic NHPs. Results: Porcine islet graft survival in consecutive diabetic NHPs (n = 7; >222, >200, 181, 89, 62, 55, and 34 days) without severe adverse events. Conclusion: We believe that our study could contribute greatly to the initiation of islet xenotransplantation clinical trials.