Conclusion
Early administration of zilucoplan prevents the onset of myopathy at the clinical and histological level in a humanized mouse model of IMNM.
Methods
purified immunoglobulin G (IgG) from an anti-HMGCR+ IMNM patient was co-injected intraperitoneally with human complement in C57BL/6, C5-deficient B10 (C5def) and Rag2 deficient (Rag2-/-) mice. Zilucoplan was administered subcutaneously in a preventive or interventional paradigm, either injected daily throughout the duration of the experiment in C57BL/6 and C5def mice or 8 days after disease induction in Rag2-/- mice.
Results
prophylactic administration of zilucoplan prevented muscle strength loss in C5def mice (anti-HMGCR+ vs. anti-HMGCR+ + zilucoplan: p = 0.0289; control vs. anti-HMGCR+ + zilucoplan: p = 0.4634) and wild-type C57BL/6 (anti-HMGCR+ vs. anti-HMGCR+ + zilucoplan: p = 0.0002; control vs. anti-HMGCR+ + zilucoplan: p = 0.0939) with corresponding reduction in C5b-9 deposits on myofibres and number of regenerated myofibres. Interventional treatment of zilucoplan after disease induction reduced the complement deposits and number of regenerated myofibres in muscles of Rag2-/- mice, although to a lesser extent. In this latter setting, C5 inhibition did not significantly ameliorate muscle strength.