Kidney Week

Abstract: INFO13-TH

PIONEER: A Basket Trial of Atacicept in Autoimmune Mediated Glomerular Disease

Session Information

• Informational Posters - 1
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• No subcategory defined

Authors

• Lafayette, Richard A., Stanford University School of Medicine, Stanford, California, United States

Richard A. Lafayette, MD

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

Jonathan Barratt, MBChB, PhD

• Brenner, Robert M., Vera Therapeutics Inc, Brisbane, California, United States

Robert M. Brenner, MD

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

Pamela D. Winterberg, MD

• Wanner, Christoph, University Hospital of Würzburg, Würzburg, Germany

Christoph Wanner, 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

Group or Team Name

• PIONEER Steering Committee.

Description

Autoimmune glomerular diseases are characterized by the presence of an autoantigen which may be of glomerular or B cell origin; these autoantigens elicit an autoantibody response by B cells. While autoimmune glomerular diseases are associated with a variety of histopathologic profiles, the fundamental pathophysiology of these kidney diseases is conserved. This mechanistic conservation invites consideration of a basket trial approach to investigate the safety and efficacy of a B-cell modulator in a broad range of glomerular diseases.

Atacicept is a rationally designed biologic protein that binds the two primary cytokines driving B cell activity: B-cell Activating Factor (BAFF) and A PRoliferation-Inducing Ligand (APRIL), with nanomolar potency. Atacicept is comprised of the extracellular binding domain of the TACI receptor fused to Fc. TACI is expressed by B cells and binds circulating BAFF and APRIL; atacicept is a soluble receptor for BAFF and APRIL amenable to chronic subcutaneous self-administration.

In Ph 2 and 3 clinical trials, atacicept has shown compelling evidence of disease modification in Immunoglobulin A nephropathy (IgAN). Recently conducted clinical trials in IgAN have generally focused inclusion on participants (pts) with high levels of proteinuria and mild-to-moderate impairment in kidney function, criteria which have rendered approximately half of all patients with biopsy-proven IgAN ineligible for enrollment. PIONEER is designed to address this gap, expanding experience with atacicept to a broader population of patients with IgAN. This study also includes pts with primary membranous nephropathy (pMN) and confirmed anti-phospholipase A2 receptor (anti-PLA2R) autoantibodies, and others with focal segmental glomerulosclerosis (FSGS) or minimal change disease (MCD) with evidence of anti-nephrin autoantibodies.

PIONEER is a global, Ph 2, basket trial designed to assess safety and detect signals of efficacy of atacicept in an expanded cohort of pts with IgAN, as well as anti-PLA2R-associated pMN and anti-nephrin-associated FSGS and MCD. Eligible pts will receive atacicept 150 mg via at-home once-weekly subcutaneous injection for up to 52 weeks. Key efficacy endpoints will include changes from baseline in UPCR, eGFR, and disease-specific antibody levels.

Funding

• Vera Therapeutics, Inc.