Safety and Efficacy Study of Zilucoplan in Subjects With Immune-Mediated Necrotizing Myopathy

Inclusion Criteria: * Clinical diagnosis of IMNM (Immune-Mediated Necrotizing Myopathy) * Positive serology for anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) or anti-signal recognition particle (SRP) autoantibodies * Clinical evidence of weakness (≤ grade 4 out of 5) on manual muscle testing in at least one proximal limb muscle group * Creatine kinase (CK) of \>1000 U/L at Screening * No change in corticosteroid dose for at least 30 days prior to Baseline or anticipated to occur during the first 8-weeks on study * No changes in immunosuppressive therapy, including dose, for at least 30 days prior to Baseline or anticipated to occur during the first 8-weeks on study Exclusion Criteria: * History of meningococcal disease * Current or recent systemic infection within 2 weeks prior to Screening or infection requiring intravenous (IV) antibiotics within 4 weeks prior to Screening * Recent initiation of intravenous immunoglobulin (IVIG) (i.e., first cycle administered less than 90 days prior to Baseline) * Rituximab use within 90 days prior to Baseline or anticipated to occur during study * Statin use within 30 days prior to Baseline or anticipated to occur during study * Plasma exchange within 4 weeks prior to Baseline or expected to occur during the 8-week Treatment Period