Eledon Pharmaceuticals’ drug to prevent islet transplantation rejection in type 1 diabetes has led to an insulin-free life in patients in a Phase I/II trial.
Preliminary data from the first six patients in the ongoing Phase I/II trial (NCT06305286) show tegoprubart’s ability to prevent the rejection of transplanted islet cells in the absence of calcineurin inhibition, resulting in sustained insulin-free management of haemoglobin A1C (HbA1c).
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The first three patients that had islet transplants over a year ago have remained insulin-free, including a patient who has maintained stable blood glucose control reflected by an HbA1c as low as 4.7% for over 15 months without the use of exogenous insulin.
Two patients who received transplants in July 2025 achieved insulin independence within approximately four weeks following a single islet transplantation and have maintained an HbA1c below 6% for more than three months.
The sixth patient, who was transplanted in early August 2025, recently underwent a second islet infusion and is now insulin-free with an HbA1c of 5.3%. All six patients have been free of severe hypoglycemic episodes since their transplants.
An anti-CD40 ligand antibody, tegoprubart was generally well tolerated with no reported serious infections, thromboembolic or rejection events. There were also no signs of kidney or neurological toxicity, all events often observed with traditional calcineurin inhibitor-based immunosuppression such as tacrolimus.
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By GlobalDataCalcineurin inhibitors are drugs used to suppress the immune system and reduce inflammation. While they are commonly used in transplants, they can cause significant adverse events, including kidney damage, and can also be toxic to the transplanted islets themselves, potentially harming their function and insulin secretion.
One of the lead investigators, Dr Piotr Witkowski, director of the Pancreas and Islet Transplant Program at UChicago Medicine, said: “For years, clinicians have been working to find a new medication that can prevent rejection of islet cells while offering a better safety profile than calcineurin inhibitors, including tacrolimus, which remain the current standard of care, but are often associated with debilitating metabolic, neurologic, and cardiovascular toxicities.”
Eledon also hopeful for kidney transplant success
The drug is also being investigated in kidney transplant, with the drug set to advance to Phase III despite missing the primary endpoint in the Phase II BESTOW trial (NCT06126380).
During the study, those dosed with tegoprubart demonstrated an estimated glomerular filtration rates (eGFR) of 69mL/min/1.73m² after 12 months while patients on standard of care (SoC) tacrolimus experienced a rate of 66mL/min/1.73m² at the same time period.
Despite its failure to meet the assigned efficacy endpoint, Eledon noted that, to its knowledge, tegoprubart’s impact on eGFR is the “highest to be reported to date” in a kidney transplant rejection prevention-focused clinical trial.
Nonprofit Breakthrough T1D, which funded the Phase I/II trial diabetes study, has also committed to funding a second study evaluating tegoprubart as part of a calcineurin inhibitor-free immunosuppression drug regimen to prevent islet transplant rejection in individuals with both type 1 diabetes and chronic kidney disease.
This is notable as research has shown that patients who received both a kidney and islet transplant had a higher frequency of kidney rejection compared to patients who received a kidney transplant alone.
