Gene-Edited Islet Cells Offer Hope for a Cure for Type 1 Diabetes

A recent proof-of-concept trial has demonstrated that genetically engineered pancreas cells can survive transplantation without the need for immunosuppressant drugs, marking a potential turning point in the treatment of type 1 diabetes (T1D). This breakthrough offers a glimmer of hope for the millions worldwide living with this chronic autoimmune condition.

Understanding Type 1 Diabetes

Type 1 diabetes occurs when the body’s immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. The World Health Organization estimated in 2017 that 9 million people globally were living with T1D. Without insulin, the body cannot effectively regulate blood glucose levels, requiring individuals to manage the disease through multiple daily insulin injections. Living with T1D is a constant, demanding task, requiring meticulous attention to diet and insulin dosage. Even with modern technologies like continuous glucose monitors and insulin pumps, individuals with T1D face a reduced life expectancy – approximately 10 years shorter than those without the condition.

The Evolution of Islet Transplantation

Islet transplantation, the process of replacing damaged islet cells with healthy ones, has shown promise in eliminating the need for insulin injections. The Edmonton protocol, developed by James Shapiro and his team in Canada, involves transplanting islets from deceased donors into a patient’s liver. While successful in many cases, this approach requires lifelong immunosuppression to prevent the body from rejecting the transplanted cells. The Nordic countries, particularly Uppsala University Hospital, have been at the forefront of islet transplantation research.

A New Approach: Gene Editing for Immune Evasion

Researchers are now exploring ways to overcome the need for immunosuppression through gene editing. Sana Biotechnology, led by Sonja Schrepfer, has developed a method to create “hypoimmune” cells that evade detection by the immune system. This involves three key genetic modifications:

• Knocking out human leukocyte antigen (HLA) class I and class II molecules, which trigger transplant rejection.
• Overexpressing CD47, a “don’t eat me” protein that protects cells from destruction by natural killer cells.

In a recent trial at Uppsala University Hospital, Per-Ola Carlsson and his team transplanted these gene-modified islets into a patient with T1D. Remarkably, the cells survived and functioned for several months without the need for immunosuppressant drugs. The results, published in August 2025, represent the first demonstration of gene-edited cells evading both transplant rejection and autoimmune attack in a human patient.

Challenges and Future Directions

Despite this significant advancement, several challenges remain. Scaling up the production of gene-modified cells is a major hurdle. Sana Biotechnology is working to create a stable master cell bank and optimize the differentiation process of stem cells into functional islets. Manufacturing involves creating a master cell bank that can be used to produce enough cells for anybody with T1D who wants a transplant. Genomic instability after gene editing can cause tumor-forming mutations.

Vertex Pharmaceuticals is pursuing a parallel strategy, differentiating pluripotent stem cells into pancreatic islets. However, their approach still requires immunosuppression, although they are also developing a hypoimmune cell program using gene editing.

The Patient Perspective and Cost Considerations

For patients with T1D, the prospect of a life free from daily insulin injections and the burden of managing their condition is profoundly appealing. Breakthrough T1D has identified freedom, mental well-being, sleep quality, and work productivity as key patient-reported outcomes for cell therapy trials. However, the high cost of these therapies and the lack of established reimbursement models pose significant challenges to widespread access.

Looking Ahead

The field of islet transplantation is rapidly evolving. With ongoing research and development, gene-edited islet cells hold the potential to revolutionize the treatment of type 1 diabetes, offering a lasting cure for millions. Sana Biotechnology hopes to file an investigational new drug (IND) application to start a Phase I trial in 2026. The next step involves using stem cells to create insulin-producing cells with the same genetic modifications.