What Defines Success in Pancreas and Islet Transplantation-Insulin Independence or Prevention of Hypoglycemia? A Review

Pancreas transplantation is considered to be the treatment of choice for selected uremic and diabetic patients, and insurance coverage is widely provided. In the USA, islet transplantation is considered to be an experimental procedure that awaits formal results of ongoing phase III trials to justify biologic licensure and transition to standard of care. Pancreas and islet registry analyses focus on different functional endpoints: insulin independence (pancreas transplants) versus avoidance of hypoglycemia (islet transplants). Although the results of islet transplants have significantly improved, the frequent use of multiple donor organs, suboptimal islet yields, and difficulties in monitoring successful engraftment or in diagnosing rejection remain major barriers that need to be overcome. Although pancreas and islet transplantations are frequently considered to be competing procedures, they are actually complementary treatment options for patients with type 1 diabetes mellitus. Because the results of pancreas transplants are superior to those for islet transplants, diabetic patients with a low surgical risk should undergo a pancreas transplantation. Type 1 diabetics with a high surgical risk (eg, serious comorbidities) should undergo an islet transplantation. Only an integrated approach to pancreas and islet transplantation, tailored to the need of the individual patient, will maximize the benefit of a scarce resource. Both procedures, if successful, have in common that they represent the only biologic treatment option to date for type 1 diabetic patients that prevents hypoglycemia long term.