Study of ALXN2050 in Proliferative Lupus Nephritis (LN) or Immunoglobulin A Nephropathy (IgAN)

This is a Phase 2, randomized, double-blind, placebo-controlled, multicenter study of ALXN2050 (120 and 180 milligrams \[mg\]) in addition to background therapy consistent with the standard of care in adult participants (≥ 18 to ≤ 75 years of age) with either LN or IgAN. The study will consist of an up to 6-week Screening Period, a 26-week blinded Initial Evaluation Period, a 24-week blinded Extended Treatment Period, and an Open-label Extension (OLE) Period of up to 2 years. Safety will be monitored throughout the study.