Ra Pharmaceuticals, Inc. announced the U.S. Food and Drug Administration’s (FDA) clearance of the Company’s Investigational New Drug (IND) application for zilucoplan for the treatment of immune-mediated necrotizing myopathy (IMNM). The Company is on track to initiate a Phase 2 clinical trial in the second half of 2019. IMNM is an autoimmune myopathy characterized by skeletal muscle necrosis, severe proximal limb weakness, and elevated creatine kinase (CK) levels. IMNM is categorized into two subtypes defined by the presence of distinct autoantibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) or signal recognition particle (SRP). In IMNM, these autoantibodies drive complement-mediated necrosis of muscle fibers, resulting in severe, progressive, and debilitating proximal muscle weakness. IMNM affects more than 15,000 patients in the United States, European Union, and Japan. There are currently no approved therapies for the treatment of IMNM. The randomized, double-blind, placebo-controlled, multi-center, Phase 2 trial will evaluate the safety, tolerability, and efficacy of zilucoplan in patients with IMNM who are positive for anti-HMGCR or anti-SRP autoantibodies. Patients will be randomized in a 1:1 ratio to receive daily subcutaneous (SC) doses of 0.3 mg/kg zilucoplan or placebo. Randomization will be stratified based on antibody status (anti-HMGCR+ versus anti-SRP+). The trial is expected to enroll approximately 24 patients with an eight-week treatment period. The primary endpoint will be change in CK from baseline to week eight. Following completion of the trial, patients will have the option to enter into an open-label long-term extension study with zilucoplan.