Sana Biotechnology Reports 14-Month Survival of Transplanted Islet Cells Without Immunosuppression in a Type 1 Diabetes Patient
Gene-edited pancreatic islet cells transplanted into a patient with type 1 diabetes continue producing insulin 14 months later with no immunosuppressive drugs, advancing the case for a functional cure.
Overview
Transplanted pancreatic islet cells engineered to evade the immune system are still producing insulin 14 months after being placed in the forearm of a 42-year-old man with type 1 diabetes, Sana Biotechnology announced on March 13, 2026. The patient has not taken any immunosuppressive medication since the transplant, a result that challenges one of the oldest barriers to cell-replacement therapy for the disease.
The first-in-human study, conducted at Uppsala University Hospital in Sweden, used Sana’s experimental therapy UP421, which consists of donor-derived islet cells genetically modified with the company’s hypoimmune (HIP) platform. The initial results through six months were published in the New England Journal of Medicine in August 2025, and the extended follow-up data strengthen the case that engineered immune evasion can provide durable graft survival in a human recipient.
What We Know
The patient had lived with type 1 diabetes for more than 30 years and had no detectable C-peptide, the standard biomarker for endogenous insulin production, at baseline. After receiving a single low dose of UP421 implanted surgically into his forearm muscle, C-peptide became measurable within weeks and has remained detectable at every monthly blood draw through month 14, according to Sana’s announcement.
C-peptide levels at month 14 were comparable to those seen in the first six months and exceeded levels recorded at months 9 and 12. Mixed meal tolerance tests confirmed the transplanted cells are responding to glucose, a hallmark of functional beta-cell behavior. A 52-week PET-MRI scan verified that islet cells remain present at the transplant site, as reported by Fierce Biotech.
No safety issues have been identified throughout the 14-month observation period. Per-Ola Carlsson, the principal investigator at Uppsala University Hospital, said the findings demonstrate “the dynamic functional capacity of beta cells transplanted in a single low dose without immunosuppression,” according to Sana.
How HIP Technology Works
Sana’s hypoimmune platform uses gene editing to modify donor cells so they can evade both arms of the recipient’s immune system: the adaptive response that rejects foreign tissue and, in type 1 diabetes specifically, the autoimmune attack that originally destroyed the patient’s own beta cells. The modifications are performed on cells outside the body before transplantation.
Islet transplantation itself is not new. The Edmonton Protocol, first described in 2000, demonstrated that infusing donor islets into the liver could restore insulin production. But that approach requires lifelong immunosuppressive drugs that carry risks including increased susceptibility to infections and cancer, limiting its use to only the most severe cases. Sana’s HIP platform aims to eliminate that trade-off entirely, as described in the NEJM publication.
What We Don’t Know
The most significant limitation is that all results come from a single patient who received a deliberately low dose. Whether the approach will work consistently across a larger population, and at doses sufficient to eliminate the need for exogenous insulin entirely, remains unproven. The current patient has achieved tighter glycemic control but has not been reported as insulin-independent.
Long-term durability beyond 14 months is also uncertain. Immune evasion could weaken over time, particularly if the gene edits are silenced or if the immune system develops alternative pathways to recognize the modified cells. The forearm transplant site, chosen for easy monitoring, differs from the liver site used in traditional islet transplantation, and it is unclear how site selection affects long-term function.
What Comes Next
Sana is using the immune evasion data from the UP421 study to develop SC451, a next-generation therapy that replaces donor-derived islets with stem cell-derived pancreatic cells, also modified with HIP technology. The company expects to file an Investigational New Drug application with the FDA and initiate a Phase 1 trial for SC451 as early as 2026, according to its announcement.
The shift to stem cell-derived cells is critical for scalability. Donor islets are scarce and variable in quality. If SC451 can replicate the immune evasion demonstrated by UP421 while using a manufactured, standardized cell source at higher doses, it could open a path toward a one-time treatment that restores normal blood glucose without insulin injections or immunosuppressive drugs for the estimated 8.7 million people worldwide living with type 1 diabetes.
Sana CEO Steve Harr said the data “highlight the potential for HIP-modified cells to survive, function, and evade immune detection long-term,” adding that the implications extend beyond diabetes to any condition that could benefit from allogeneic cell transplantation, according to the company.