The study will be conducted in 2 parts: Part A (Phase 2) and Part B (Phase 3). There will be 3 periods in both Part A and Part B of this study: Screening Period, Randomized Controlled Period, and Open-Label Extension Period.
This is a Phase 2/3, double-blind, randomized, placebo-controlled, parallel group, multicenter study to evaluate the efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity of ravulizumab in adult participants with dermatomyositis (DM).