The International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--chapter 6: Patient selection for pilot clinical trials of islet xenotransplantation.

Several clinical scenarios would justify trials of islet xenotransplantation, including islet after kidney (IAK) transplantation and islet xenotransplantation for hypoglycemia unawareness. In selecting a patient cohort, several factors unique to xenotransplant trials must be considered, including the potential for unique infective complications, the risks of immunosuppression, and the requirement for life-long monitoring. These factors need to be balanced against the benefits of improved glycemic control and ability to deliver large numbers of high-quality islets, something more difficult to achieve in islet allotransplantation. The importance of these risks varies depending on the patient cohort selected and proposed therapy to be undertaken. In islet xenotransplantation for hypoglycemia unawareness, immunosuppressive risks, and problems with life-long monitoring need special attention in trial design. Whereas in IAK xenotransplantation, consideration must be given to ensure that the procedure does not impact on renal allograft outcomes and patient co-morbidity, which is already significant in renal transplant recipients. This review outlines the rationale for undertaking islet xenotransplantation in highly select patients with type 1 diabetes and addresses some of the unique challenges. At present, no clear consensus exists as to the most appropriate patient group for the first trials of islet xenotransplantation. Rather, this will depend on the type of treatment being proposed, the potential infective risks and the overall burden of immunosuppression.