Can stem cells cure type 1 diabetes?

Type 1 diabetes mellitus involves loss of insulin production due to autoimmune destruction of pancreatic islet cells. In the lab, researchers can coax embryonic stem cells to develop into functional islet cells. If these islet cells can be transplanted successfully and safely into people, it would represent a breakthrough for diabetes treatment.

Researchers now report phase 1–2 results from an ongoing, industry-sponsored study of the safety and efficacy of stem cell–derived islet cells (zimislecel) for type 1 diabetes. Zimislecel is a single infusion administered via the portal vein along with a transplant-based immunosuppression protocol. Of the 22 patients who received zimislecel, 14 (mean age, 44) completed at least 12 months of follow-up. Twelve patients were still alive at the time of the report, and all had endogenous production of insulin and substantial improvements in glycemic control; 10 patients were able to discontinue insulin. Two patients died (at 20 and 30 months of follow-up); one death was related to immunosuppression.

These results represent a remarkable scientific achievement for stem cell research; however, we do not know if zimislecel will hold up to further scrutiny in phase 3 studies and beyond. Although the treatment potentially obviates some issues with pancreatic transplants (e.g., organ availability and surgical complexity), it still requires immunosuppression.