Dutch researchers have made a major breakthrough in treating severe type 1 diabetes by using lab-grown insulin-producing cells derived from stem cells. In a recent clinical trial involving people prone to dangerous hypoglycaemia, a single infusion of these fully mature, stem-cell-derived islet cells—called zimislecel—was administered through the portal vein. A year later, all patients experienced a complete stop in severe hypoglycaemic episodes, and 10 out of 12 became insulin-independent.
These lab-grown islets function remarkably well: they sense blood sugar and release insulin accordingly, much like natural pancreatic cells. Results showed sustained blood sugar control, with participants spending over 70% of the time within the healthy glucose range (70–180 mg/dL) and average HbA1c below 7%. This heralds a major shift away from daily insulin injections towards restoring the body’s own insulin production.
The zimislecel cells are fully differentiated before infusion, which appears crucial. This avoids the inefficiencies and unpredictability of immature cell therapies. By manufacturing these ready-to-go islets at scale, the approach can circumvent the shortage of donor organs associated with traditional transplants. Moreover, notably, no glucocorticoid steroids were used to deliver the cells—an important step toward safer application.
However, immunosuppression remains necessary to prevent rejection, which carries risks like neutropenia and infection—and two trial participants sadly died, although their deaths were linked to preexisting conditions or post-procedural complications. While early results are promising, the team acknowledges the need for larger, longer-term studies to verify safety, durability, and immune management.
Overall, this zimislecel trial marks a seismic step toward a functional cure for type 1 diabetes and could redefine treatment. A larger Phase 3 trial is already underway, with the goal of full regulatory approval by 2026. If sustained, this therapy could free millions from lifelong insulin dependency, transforming the landscape of diabetes care.