A Study of Zigakibart in Adults With IgA Nephropathy

Approximately 330 participants with eGFR ≥ 30 mL/min/1.73m\^2 and with biopsy-proven IgAN will be randomized to receive 600 mg Q2W BION-1301, Novartis FUB523, or a matched placebo for 104 weeks. An additional exploratory cohort, not included in the primary analysis, will be comprised of approximately 20 participants (10 participants per arm) with biopsy-confirmed IgAN and eGFR of ≥ 20 to \< 30 mL/min/1.73 m\^2. The exploratory cohort will be randomized using the same schema as the primary cohort. The primary objective of the study is to evaluate the effect of BION-1301 versus placebo on eGFR as measured by the change from Baseline in eGFR. Following completion of the 104-week treatment period, subjects may be eligible to enroll in an open-label extension (OLE) study to receive open-label treatment with BION-1301 under a separate protocol. Subjects who do not enroll in the OLE will enter the protocol-specified 24-week safety follow-up period. To facilitate study participation over this time period, other visits may be remote (away from study site) for participants who elect to self-administer the study drug.