Kidney Week

Abstract: INFO08-SA

A Phase 2, Open-Label Trial to Examine Kidney Tissue-Specific Effects of Felzartamab in Adults with IgAN

Session Information

• Informational Posters - 3
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• No subcategory defined

Authors

• Barratt, Jonathan, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom

Jonathan Barratt, MBChB, PhD

• Kretzler, Matthias, Division of Nephrology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, United States

Matthias Kretzler, MD

• Alenizi, Saif A., Biogen, South San Francisco, California, United States

Saif A. Alenizi

• Flesher, Donna, Biogen, South San Francisco, California, United States

Donna Flesher, PhD

• Shah, Millie, Biogen, South San Francisco, California, United States

Millie Shah, PhD

• Beckett, Valeria, Biogen, South San Francisco, California, United States

Valeria Beckett

• Griffin, Noelle, Biogen, Cambridge, Massachusetts, United States

Noelle Griffin, PhD

• Patel, Uptal D., Biogen, South San Francisco, California, United States

Uptal D. Patel, MD

• Schwartz, Brian, Biogen, South San Francisco, California, United States

Brian Schwartz, MD

• Lafayette, Richard A., Division of Nephrology, Department of Medicine, Stanford University, Stanford, California, United States

Richard A. Lafayette, MD

Description

Immunoglobulin A nephropathy (IgAN) results from immune complex accumulation in the glomerular mesangium leading to kidney injury and dysfunction, and is thought to be driven by CD38⁺ plasma cells that produce pathogenic antibodies. In the Phase 2 IGNAZ study, felzartamab, a human monoclonal antibody targeting CD38⁺ plasma cells and plasmablasts, was generally well tolerated, led to a rapid reduction in proteinuria that persisted off treatment, and slowed estimated glomerular filtration rate (eGFR) decline. While these clinical effects suggest meaningful activity, this single-arm, open-label Phase 2 study will evaluate the impact of felzartamab on kidney tissue–specific and peripheral biomarkers, clinical efficacy, and safety.

Approximately 25 adults with biopsy-confirmed IgAN within 5 years of screening will receive felzartamab over 24 weeks, followed by an 80-week observation period off-treatment (Figure). Participants must have eGFR ≥30 mL/min/1.73m², proteinuria ≥0.5 g/day or 24h urine protein-creatinine ratio (UPCR) ≥0.5 g/g, and be clinically stable on a maximally tolerated dose of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker for ≥12 weeks prior to screening (those intolerant may enroll). The primary endpoint is change in mesangial IgA deposition by immunofluorescence from baseline to Week 36. Secondary endpoints include change in mesangial IgA deposition, percent change in proteinuria (24h UPCR), change in eGFR, proportion of participants with complete response, proportion meeting the composite kidney outcome endpoint (eGFR decline, dialysis or kidney transplant, or death), safety, pharmacokinetics, and immunogenicity. Exploratory endpoints include efficacy, kidney tissue–specific and peripheral biomarkers, intrarenal molecular profiles, and histology in protocol kidney biopsies obtained at Weeks 0, 36, and 104.

This study will inform on the impact of felzartamab on mesangial IgA deposition, kidney tissue–specific and peripheral biomarkers, efficacy, and safety, and will help to further elucidate the durable, disease-modifying potential of felzartamab in IgAN.

Funding

• This study is sponsored by Biogen.