Eledon's tegoprubart hits 100% insulin independence in T1D islet trial
Eledon Pharmaceuticals has reported updated results from an investigator-initiated pilot study of tegoprubart, its anti-CD40L antibody, used as part of a calcineurin inhibitor-free immunosuppression regimen in patients with type 1 diabetes (T1D) undergoing allogeneic islet cell transplantation at the University of Chicago Medicine Transplant Institute. The data were presented at the American Diabetes Association's 86th Scientific Sessions on 8 June 2026.
All 12 enrolled patients achieved insulin independence — meaning they no longer required chronic exogenous insulin therapy — with stable islet graft function observed across a median follow-up of eight months and a maximum of 22 months. The cohort also demonstrated a mean most recent HbA1c of approximately 5.4%, below the 6.5% diabetic threshold, representing an average improvement of roughly 2.6 percentage points from a pre-transplant mean of around 8.0%. All patients had a history of recurrent severe hypoglycaemic episodes prior to transplantation; none were reported post-transplant.
Trial detail and safety profile
The pilot enrolled 12 adults with long-standing T1D — median disease duration approximately 33 years — who received tegoprubart as the cornerstone of a regimen deliberately designed to avoid tacrolimus and other calcineurin inhibitors (CNIs). CNIs are current standard-of-care for transplant rejection prevention but carry well-documented risks of nephrotoxicity, hypertension, neurotoxicity, and direct harm to insulin-producing islet cells, which makes long-term use problematic in this patient population. The Eledon team reported no rejection episodes, no development of de novo donor-specific HLA antibodies, and no evidence of the CNI-associated adverse events listed above. Adverse events that did occur were generally managed by dose reduction of mycophenolic acid.
The company also noted higher levels of post-transplant islet cell engraftment with the tegoprubart regimen compared with historical tacrolimus-treated patients at the same centre — a finding that, while not from a randomised head-to-head comparison, adds to the mechanistic rationale for CD40L blockade in this setting.
David-Alexandre C. Gros, Chief Executive Officer of Eledon, said the regimen "may protect an islet cell graft without the long-term burden associated with calcineurin inhibitors, the current standard of care."
Market context and regulatory path
Islet cell transplantation has long occupied a niche position in T1D management, constrained by limited donor supply, the toxicity of immunosuppression, and lack of regulatory approval in the United States — the FDA approved the first allogeneic islet cell product, Lantidra, only in 2023. Tegoprubart's anti-CD40L mechanism places it in the same broad class as prior candidates that failed on thromboembolic safety grounds; Eledon has presented tegoprubart as an engineered antibody designed to address that liability, though the pilot study scale is too small to draw firm conclusions on rare adverse events.
Eledon said it intends to seek FDA regulatory guidance on a path to market for tegoprubart in islet cell transplantation later in 2026. The study was funded by Breakthrough T1D, whose chief executive Aaron Kowalski described insulin independence without traditional immunosuppression burden as "one of cell replacement therapy's biggest goals." Breakthrough T1D has also committed funding for a second study evaluating the drug in T1D patients with concurrent chronic kidney disease — a population where CNI toxicity is particularly acute.
The broader competitive landscape for CNI-free transplant immunosuppression is active, with a number of academic and industry programmes exploring co-stimulation blockade and regulatory T-cell approaches. The 12-patient cohort and largely investigator-driven design mean peer-reviewed publication and longer follow-up data will be essential before the field can assess tegoprubart's durability and commercial viability in earnest.