Clinical islets transplantation from deceased donors was established as an experimental protocol by Prof Paul Lacy (Missouri) in the early 90s with a major goal to cure T1D. However, success rate was low. A decade later, a group from Edmonton, led by Prof James Shapiro, established a steroid-free immunosuppression therapy. Using this protocol, they greatly improved long-term viability and performance of transplanted islets. These patients are frequently reported as normoglycemic and insulin-free for extended periods of time.
Two major drawbacks are associated with the Edmonton protocol. Firstly, it is dependent on fairly large number of donor islets – average of 2 pancreata per patient. In a world of large shortage of donor organs this fact severely limits number of treatments. Secondly, transplantation is dependent on life-long use of immunosuppressive drugs. Notably, long-term use of these drugs is associated with significant morbidity (e.g. malignancies, hypertension, and opportunistic infection). As a result, human allogeneic islet transplantation has not been widely adopted by the medical community. Limited number of clinical procedures have been performed globally, less than 3000 during a period of almost two decades.