‣ Part A:

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

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

• Indication-specific criteria:

∙ 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,

• Anti-dsDNA at screening. Anti-dsDNA testing is required but the result need not be positive.

• 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.

∙ Part B:

• Participants meet at least 1 of the following criteria:

‣ Completed investigational product (IP) treatment and 24 weeks of follow-up in Part A, or

⁃ Had IP interruption(s) in Part A, but did not permanently discontinue IP, and completed study visits up to the last scheduled visit of the follow-up period of Part A.