All 10 Evaluable Patients Achieve Insulin Independence in Eledon's Type 1 Diabetes Islet Transplant Trial

For people who have lived with Type 1 diabetes for decades, the idea of waking up each morning without needing insulin injections can feel impossibly distant. A new clinical trial from the University of Chicago Medicine is offering a glimpse of what that future might look like, with results that have quietly stunned the transplant community.

The trial, led by Piotr Witkowski, M.D., Ph.D., Director of the Pancreas and Islet Transplant Program at UChicago Medicine, enrolled 12 adults with long-standing Type 1 diabetes. The participants had been living with the disease for a median of 33 years and had an average HbA1c of approximately 8.0% before entering the trial. Each person underwent allogeneic islet transplantation, a procedure in which donor insulin-producing cells called islets are infused into the recipient's liver, where they take up residence and begin producing insulin on their own.

What makes this trial different from earlier islet transplant efforts is the immunosuppression regimen. Historically, patients who received islet transplants had to take drugs called calcineurin inhibitors, most commonly tacrolimus, to prevent their immune systems from rejecting the new cells. The problem is that tacrolimus itself is toxic to the kidneys over time and can cause high blood pressure and nerve damage, creating a difficult trade-off for patients who are already at risk for these complications from diabetes itself.

In this trial, participants instead received tegoprubart, an anti-CD40L monoclonal antibody developed by Eledon Pharmaceuticals. Tegoprubart works by blocking a specific signaling pathway that the immune system uses to mount rejection attacks, without the kidney and blood pressure side effects associated with tacrolimus. This approach, called a calcineurin inhibitor-free regimen, has long been a goal in transplant medicine, and this trial represents one of the most promising attempts to achieve it in a Type 1 diabetes population.

The updated results, presented in March 2026 at the Advanced Technologies and Treatments for Diabetes conference in Barcelona, were striking. Of the 12 patients enrolled, 10 were more than four weeks post-transplant and fully evaluable at the time of the data cutoff. Every single one of those 10 patients had achieved insulin independence, meaning they no longer required daily insulin injections. Every one also had a most recent HbA1c below 6.0%, which falls within the normal range for people without diabetes. The mean HbA1c across the group was approximately 5.35%, a level that most people with Type 1 diabetes, even well-managed, rarely reach. One participant, transplanted more than 15 months ago, maintained an HbA1c as low as 4.7% throughout that period with no exogenous insulin at all.

From a safety standpoint, the results were equally encouraging. Not a single patient experienced a rejection episode. None developed de novo donor-specific HLA antibodies, which are a marker of immune rejection activity. And critically, none showed signs of the kidney damage, high blood pressure, or nerve toxicity that commonly accompany tacrolimus-based regimens. The tegoprubart regimen was generally well tolerated, and any side effects related to the accompanying immunosuppressant mycophenolic acid were manageable by adjusting the dose.

It is important to note that islet transplantation remains a complex procedure that requires a donor, carries the risks of any transplant, and requires ongoing immunosuppression to maintain function. It is not yet a widely available treatment, and the trial is still in early stages with a small number of participants. Longer follow-up will be needed to understand how durable these results are over time. Nevertheless, for a disease that has resisted a cure for over a century, these numbers represent a meaningful and well-documented step forward.

Breakthrough T1D, a leading Type 1 diabetes research organization, has committed funding for a follow-up study that will evaluate tegoprubart specifically in people with both Type 1 diabetes and chronic kidney disease, a population for whom calcineurin inhibitor toxicity poses an even greater danger and for whom safe islet transplantation could be life-changing.