Kidney Week

Abstract: FR-PO0713

Budoprutug for Minimal Change Disease (MCD): A Case Study of Durable Response and Potential Disease Modification via CD19+ B-Cell Depletion

Session Information

• Glomerular Diseases: Membranous Nephropathy, FSGS, and Podocytopathies
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Cortazar, Frank B., New York Nephrology Vasculitis and Glomerular Center, Albany, New York, United States

Frank B. Cortazar, MD

• Cordero, Tatiana L., New York Nephrology Vasculitis and Glomerular Center, Albany, New York, United States

Tatiana L. Cordero

• Phelan, Howard J., New York Nephrology Vasculitis and Glomerular Center, Albany, New York, United States

Howard J. Phelan

• Charles, Edgar D., Climb Bio, Inc., Wellesley, Massachusetts, United States

Edgar D. Charles, MD

Introduction

Minimal change disease (MCD) is an immune-mediated podocytopathy characterized by development of nephrotic syndrome. In ~50% of adults, treatment is complicated by frequent relapses (≥2 relapses/6 months or ≥4 relapses/year [KDIGO guidelines]) and/or steroid-dependent disease (relapse within 2-4 weeks of stopping steroids). Discovery of anti-nephrin autoantibodies in a significant portion of patients provides rationale for steroid sparing, B-cell targeted therapy. Budoprutug (TNT119) is an investigational CD19 mAb with high affinity for CD19 and enhanced ADCC. Since CD19 is expressed from early B-cell development through plasmablasts and plasma cell subsets, budoprutug may durably deplete pathogenic autoantibody-producing B cells. We present a first report of an MCD patient treated with budoprutug.

Case Description

A 56-yr old white woman with frequently relapsing, biopsy-proven primary MCD was enrolled into NCT05441826 while receiving a glucocorticoid taper for treatment of relapse. The patient was most recently treated with a 6-month steroid course, with remission that lasted ~1 month after steroid discontinuation. The patient was restarted on steroids and enrolled onto the study when prednisone was tapered down to 7.5 mg/day. At baseline, she had no edema with UPCR 0.05 g/g, eGFR 78 mL/min/1.73 m², serum albumin 4.5 g/dL, and total B cells 238 cells/μL. She received 4 doses of IV budoprutug: 100 mg on Days 1, 15 and 200 mg on Days 169, 183, and was maintained on protocolized prednisone taper that ended on Day 85 of the study. Total B-cell count decreased to <LLOQ (4.6 cells/μL) on Day 8 and stayed <LLOQ for the duration of the study (Day 274). B-cell reconstitution was documented ~two years after Day 1. The patient remained asymptomatic, in complete remission, and steroid-free, with UPCR <0.3 g/g and normal eGFR, until a relapse occurred three years after first dose of budoprutug. The patient had 1 TEAE (unrelated to study drug) of right axillary nodule on Day 155, which resolved on Day 189 without intervention. No infusion-related reactions occurred.

Discussion

In this case study of first use of budoprutug in MCD, a patient with frequently relapsing disease experienced a prolonged steroid-free remission. Targeting CD19 may be an effective strategy for treating complicated MCD and warrants additional study.