The U.S. Food and Drug Administration cleared Ra Pharmaceuticals application to begin a human clinical trial of zilucoplan, its experimental therapy for the treatment of immune-mediated necrotizing myopathy.

The Company is on track to initiate a phase 2 clinical trial of the drug in the second half of 2019.

Immune-mediated necrotizing myopathy (IMNM) is an autoimmune myopathy characterized by skeletal muscle necrosis, severe proximal limb weakness, and elevated creatine kinase levels. IMNM is categorized into two subtypes defined by the presence of distinct autoantibodies. In IMNM, these autoantibodies drive complement-mediated necrosis of muscle fibers, resulting in severe, progressive, and debilitating proximal muscle weakness. There are currently no approved therapies for the treatment of IMNM.

Zilucoplan is an investigational, synthetic, macrocyclic peptide that inhibits compliment C5, a part of the body’s immune system that when activated in an uncontrolled manner, plays a role in severe rare disorders like IMNM.

The company is developing zilucoplan for subcutaneous self-administration for generalized myasthenia gravis, IMNM, and other tissue-based, complement-mediated disorders.

“Given the availability of diagnostic autoantibodies and the central role of terminal complement activation in the pathophysiology of the disease, zilucoplan has the potential to become a targeted therapy for patients with IMNM,” said Andrew Mammen, muscle disease unit leader for the  Laboratory of Muscle Stem Cells and Gene Regulation, and Principal Investigator for the phase 2 study at the National Institute of Arthritis and Musculoskeletal and Skin Diseases. “The results observed in the recent phase 2 clinical trial of zilucoplan in generalized myasthenia gravis, a neuromuscular disease similarly characterized by autoantibody-mediated complement activation and tissue injury, provide strong rationale for the clinical evaluation of zilucoplan in this disease.” 

Photo: Andrew Mammen, muscle disease unit leader for the Laboratory of Muscle Stem Cells and Gene Regulation

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