In Vitro: Zilucoplan (RA101495; 1-1000 nM; 30 min) inhibit Lipopolysaccharides-induced increase in C5a plasma levels in human whole blood with an IC50 value of 474.5 pM. Zilucoplan has a 65.7% reduction in C5a plasma levels observed at a concentration of 1 nM. Zilucoplan bins to complement component 5 (C5) and blocks the downstream assembly of the membrane attack complex (MAC; C5b-9) by inhibiting the cleavage of C5 by the C5 convertase into C5a and C5b and binding to preformed C5b to sterically block interaction with C6, thereby inhibiting the formation of membrane pores and subsequent cell death.
In Vivo: Zilucoplan (RA101495; 10 mg/kg; S.C.; daily, for 6 d) prevents the development of immune-mediated necrotising myopathy (IMNM) in C5-deficient mice supplemented with human complement. Zilucoplan (10 mg/kg; S.C.; daily, for 6 d) has protection on myopathy prevention in C57BL/6 mice.