Eledon's Tegoprubart Shows Major Quality of Life Gains in Kidney Transplants

IRVINE, Calif. – October 26, 2026 — For decades, the success of a kidney transplant has been measured by two primary, binary outcomes: the prevention of organ rejection and the preservation of graft function. However, a growing movement within transplant medicine is challenging this paradigm, arguing that the heavy physical and mental toll of standard immunosuppressive drugs often leaves patients surviving, rather than thriving.

New data presented by Eledon Pharmaceuticals, Inc. at the American Society of Nephrology (ASN) Kidney Week 2026 in Denver, Colorado, suggests a long-awaited shift may finally be on the horizon. The clinical-stage biotechnology company unveiled highly positive patient-reported outcomes from its Phase 2 BESTOW trial, demonstrating that its investigational immune-modulating therapy, tegoprubart, delivered sustained, statistically significant improvements in health-related quality of life compared to tacrolimus, the current standard of care.

The findings provide compelling evidence that replacing highly toxic calcineurin inhibitors (CNIs) like tacrolimus with targeted biologic therapies could fundamentally transform the everyday lives of transplant recipients.

A Paradigm Shift in Patient Experience

The Phase 2 BESTOW trial evaluated patients over a 12-month period following a kidney transplant, utilizing two rigorously validated measures of symptom burden: the Modified Transplant Symptom Occurrence and Symptom Distress Scale (MTSOSD-59R) and the Kidney Disease Quality of Life Short Form (KDQOL-SF).

According to the data, patients treated with tegoprubart reported continued reductions in symptom occurrence from baseline at both six and 12 months. In stark contrast, those in the tacrolimus arm saw a slight initial decline in symptoms that ultimately reversed, ending up slightly worse than their baseline levels by month 12.

The granular data is even more striking. Across 23 specific domains where differential improvement was observed—spanning neurological, gastrointestinal, metabolic, and physical categories—tegoprubart demonstrated greater symptom improvement than tacrolimus in 22 of them. Conversely, tacrolimus drove greater symptom worsening in all 22 domains where differential worsening was recorded.

"Success after kidney transplantation is measured not only by preventing rejection and preserving graft function, but also by how patients feel and function in their everyday lives," said presenting author Andrew Adams, M.D., Ph.D., Professor of Surgery and Chief of the Division of Transplantation at the University of Minnesota. "What is particularly compelling about these BESTOW results is the consistency of the patient-reported benefits when treated with tegoprubart compared with tacrolimus... The extent of separation between treatment groups suggests patients receiving tegoprubart may experience meaningful quality of life advantages."

Clinically significant milestones were also reached on the KDQOL-SF scale, where a change of three to five points is considered meaningful. Tegoprubart achieved a mean improvement from baseline of 9.0 points on the symptoms and problems subscale, compared to just 3.3 points for tacrolimus. Mental health outcomes mirrored this trend; the SF-12 mental component summary score increased by 1.5 points for the tegoprubart group, while the tacrolimus group experienced a 1.6-point decline.

The Resurgence of CD40L Inhibition

To understand the significance of tegoprubart's success, one must look at the turbulent history of the biological pathway it targets. Tegoprubart is an anti-CD40L antibody, designed to block the CD40 Ligand—a critical communication bridge in the activation of the adaptive and innate immune systems.

In the early days of transplant immunology, first-generation CD40L inhibitors like ruplizumab were heralded as potential "holy grails" for their ability to prevent rejection without depleting lymphocytes. However, those early drugs were derailed by severe thromboembolic complications. Researchers later discovered that the Fc region of those early antibodies was inadvertently activating blood platelets, causing dangerous clots.

Tegoprubart represents a triumph of modern protein engineering. The IgG1 antibody has been specifically engineered to lack the problematic Fc receptor interaction, effectively neutralizing the thromboembolic risks that plagued its predecessors. By successfully blocking the CD40L pathway without triggering platelet activation, Eledon has revived a highly promising mechanism of action.

Transplant specialists note that the ability to modulate the immune system without the widespread cellular destruction caused by older therapies is a massive leap forward. By promoting a more tolerogenic environment—where the body is coaxed into accepting the new organ rather than aggressively fighting it—tegoprubart minimizes the collateral damage that leads to chronic side effects.

Beyond Symptoms: Efficacy and Long-Term Graft Health

While quality of life is a crucial metric, any drug seeking to displace tacrolimus must first prove it can keep the transplanted kidney alive and functioning. Previous readouts from the BESTOW trial indicate that tegoprubart is more than capable of holding its own on this front.

Eledon had previously reported that tegoprubart-treated patients maintained statistically significantly higher estimated Glomerular Filtration Rates (eGFR), the primary indicator of kidney function. At 24 months, patients on tegoprubart showcased an eGFR advantage of approximately 13 mL/min/1.73 m² over those on tacrolimus. Furthermore, no cases of biopsy-proven acute rejection were reported in the tegoprubart arm beyond six months post-transplant, compared to seven cases in the tacrolimus cohort.

"The patient-reported outcomes presented at ASN Kidney Week provide perhaps the clearest picture yet of what tegoprubart’s differentiated profile means for transplant patients in everyday life," said David-Alexandre C. Gros, M.D., Chief Executive Officer of Eledon. "We previously reported encouraging BESTOW results across efficacy, kidney function and safety measures, which alone strengthened our belief in tegoprubart. The additional findings... address one of the most important unmet needs in organ transplantation."

Currently, an overwhelming majority of BESTOW trial participants (96% of the tegoprubart arm) have opted to continue into a global open-label extension study, underscoring the high patient tolerability and sustained efficacy of the treatment.

The Road to Displacing a Giant

Despite the glowing data, Eledon faces a steep commercial and clinical uphill battle. Tacrolimus has been the bedrock of transplant immunosuppression for decades. It is cheap, universally understood by transplant surgeons, and undeniably effective at preventing acute rejection, even if its long-term toxicity profile—which includes nephrotoxicity, diabetes, and severe tremors—leaves much to be desired.

Convincing a traditionally conservative medical community to adopt a novel, likely more expensive biologic will require unimpeachable Phase 3 data. Armed with a Fast Track designation from the U.S. Food and Drug Administration, Eledon is preparing to initiate the global Phase 3 LEGACY trial in the fourth quarter of 2026. The trial is expected to enroll approximately 600 patients and will utilize a composite efficacy failure endpoint to prove non-inferiority to tacrolimus at 52 weeks, while simultaneously tracking the sustained kidney function and patient-reported outcomes observed in Phase 2.

Industry analysts point out that Eledon is not alone in the race to replace calcineurin inhibitors. Competitors like Sanofi, with its drug candidate riliprubart, are also advancing therapies in the kidney transplant rejection pipeline. However, Eledon's robust financial runway, which extends through the second quarter of 2027, positions the company well to execute its late-stage development plans without immediate capital constraints.

If the forthcoming Phase 3 LEGACY trial replicates the success of BESTOW, the transplant community may finally have a therapeutic option that does not force patients to choose between keeping their new organ and preserving their quality of life. For the thousands of patients who undergo kidney transplantation each year, the promise of a life free from the debilitating side effects of legacy immunosuppressants is closer than ever to becoming a reality.