An Open-label Study of Povetacicept in Autoantibody-Associated Glomerular Diseases

Key Inclusion Criteria Summary:

1. Biopsy-confirmed autoantibody-associated glomerular disease: immunoglobulin A nephropathy (IgAN), primary membranous nephropathy (pMN), or lupus nephritis (LN) 2.

Indication-specific criteria:

a. IgAN

• Biopsy-confirmed diagnosis less than or equal to (≤)10 years prior to the start of screening AND Screening UPCR greater than or equal to (≥)0.5 g/g.

• No background immunosuppression therapies.

pMN

• A historical biopsy-confirmed diagnosis with positive anti-PLA2R1 antibodies or anti-THSD7A antibodies at screening AND Screening UPCR ≥1 g/g

• Inadequate reduction of proteinuria determined by the Principal Investigator (PI) despite optimal supportive care for at least 12 weeks.

• No background immunosuppression therapies except for optional calcineurin inhibitors.

LN

• A Biopsy-confirmed diagnosis of active, proliferative Class III, IV, (with or without Class V) LN ≤6 months prior to the start of screening AND

• Screening UPCR ≥1 g/g,

• Positive anti-dsDNA at screening

• On stable background immunosuppression ≥ 8 weeks prior to Day 1

AAV

•

Past diagnosis of renal AAV, defined as either of the following:

• History of renal biopsy consistent with renal AAV.

• History of clinically diagnosed renal AAV.

• Myeloperoxidase (MPO)-ANCA or proteinase 3 (PR3)-ANCA positive by enzyme-linked immunosorbent assay at screening.

• At least 4 weeks since initiation of AAV induction therapy, if applicable.

3. On maximal dose or the maximally tolerated dose ACEis/ARBs for ≥12 weeks prior to study Day 1

Key Exclusion Criteria Summary:

1. Prior diagnosis of, or fulfills diagnostic criteria for, another renal disease

2. eGFR <30 (milliliter per minute per square meter (mL/min/1.73m^2) or rapidly progressive glomerulonephritis

3. Recent serious or ongoing infection; risk or history of serious infection

4. Receipt of B cell depleting therapies or anti-BAFFand/or APRIL therapies within protocol specified timeframes