Evaluation of Efficacy of Povetacicept in Adults With Immunoglobulin A Nephropathy (IgAN)

Key Inclusion Criteria: * Diagnosed IgAN, with biopsy confirmation * 24-hr proteinuria excretion ≥1.0 g/day or 24-hour uPCR ≥0.75 g/g * Estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73m\^2 * Stable angiotensin converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARBs) as per protocol specification Key Exclusion Criteria: * Have received any immunosuppressive treatment or procedures (including corticosteroids, oral immunosuppressive agents, B cell or plasma cell targeted therapies, complement targeted therapies, herbal medicines per protocol, and tonsillectomy) within a wash-out period per protocol * Rapidly progressive glomerulonephritis with eGFR reduction \>50% within 12 weeks of the start of screening Other protocol defined Inclusion/Exclusion criteria may apply.