Kidney Week

Abstract: SA-OR079

Interim Results from the Adult IgAN and Primary Membranous Nephropathy (pMN) Cohorts in the Atacicept PIONEER Trial

Session Information

• Late-Breaking Research Orals: Pediatrics, Genetics, and Glomerular Diseases
  October 24, 2026 | Location: Four Seasons Ballroom 2, Convention Center
  Abstract Time: 05:42 PM - 05:54 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Lafayette, Richard A., Stanford University, Stanford, California, United States

Richard A. Lafayette, MD

• Barratt, Jonathan, University of Leicester, Leicester, England, United Kingdom

Jonathan Barratt, MBChB, PhD

• Mix, Chris, Vera Therapeutics Inc, Brisbane, California, United States

Chris Mix, MD, MS

• Rizk, Dana V., University of Alabama at Birmingham Health System, Birmingham, Alabama, United States

Dana V. Rizk, MD

• Rovin, Brad, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States

Brad Rovin, MD, FASN

• Winterberg, Pamela D., Vera Therapeutics Inc, Brisbane, California, United States

Pamela D. Winterberg, MD

• Sheng, Tao, Vera Therapeutics Inc, Brisbane, California, United States

Tao Sheng, PhD

• Tumlin, James A., Emory University School of Medicine, Atlanta, Georgia, United States

James A. Tumlin, MD, FASN

• Chertow, Glenn M., Stanford University School of Medicine, Stanford, California, United States

Glenn M. Chertow, MD, MPH, FASN

• Wanner, Christoph, Julius-Maximilians-Universitat Wurzburg, Würzburg, BY, Germany

Christoph Wanner, MD

Background

Several glomerular diseases result from B-cell-driven production of antibodies that mediate kidney injury. Atacicept is a native human TACI-Fc fusion protein that inhibits BAFF and APRIL, key cytokines that drive B-cell activity. In ORIGIN 2b/3, atacicept reduced proteinuria and improved IgAN disease markers. PIONEER is a global, open-label, Phase 2 trial evaluating atacicept in multiple antibody-mediated glomerular diseases, including presentations of IgAN excluded from ORIGIN 2b/3 and anti-PLA2R-positive pMN.

Methods

Adults receive atacicept 150 mg SC weekly for 52 weeks. IgAN cohorts include reduced eGFR (<30 mL/min/1.73 m²), moderate proteinuria (UPCR 0.5–1.0 g/g), high proteinuria (≥5 g/g), IgA vasculitis with nephritis (IgAVN), and post-transplant recurrence. Objectives include safety/tolerability and change from baseline (BL) in proteinuria and disease-specific antibodies (Gd-IgA1, anti-PLA2R).

Results

94 adults with IgAN, including 14 with IgAVN and 6 with post-transplant recurrence are included in this Aug 2026 analysis. Mean change from BL in 24h-UPCR was –34% (SE 3.2) at Week 12 and –41% (SE 7.7) at Week 24 with similar reductions seen across adult IgAN cohorts. The analysis also includes 10 adults with pMN. Mean change from BL in anti-PLA2R antibody level at Week 4 was –63% (SE 6.0), with 1 of 7 achieving anti-PLA2R <14 RU/mL. Change from BL 24h-UPCR at Week 12 was -32% (SE 6.9), with 3 of 3 achieving resolution of BL nephrotic-range proteinuria. No new safety signals or clinically significant hypogammaglobulinemia have been observed. Updated analyses will be presented.

Conclusion

Atacicept treatment in adults with IgAN and low eGFR or low proteinuria at BL resulted in similar reductions in 24h-UPCR as reported in ORIGIN 2b/3. In adults with pMN, atacicept treatment resulted in rapid reduction in anti-PLA2R antibody levels, detectable at Week 4, the earliest reported response to a B-cell modulatory therapy in pMN, and similar in magnitude as B-cell depleting therapies at this time point. These findings support the broader therapeutic potential of atacicept across these antibody-mediated glomerular diseases.

Funding

• Commercial Support – Vera Therapeutics