Successful Treatment of a PNH Patient Non‐responsive to Eculizumab with the Novel Complement C5 Inhibitor Coversin (Nomacopan)

Paroxysmal Nocturnal Haemoglobinuria (PNH) is an acquired bone marrow disease characterized by haemolysis, thrombosis and bone marrow failure. The complement C5 inhibitor eculizumab reduces haemolysis, improves symptoms and decreases the risk of PNH-related complications. Failure to respond to eculizumab has been reported in patients with an Asian ancestry who have a polymorphism at p.Arg885His in their C5 protein. This polymorphism interferes with the binding of eculizumab to C5. We describe a different genetic variant of C5 (p.Arg885Ser) in a PNH patient with no Asian ancestry and report on the efficacy, safety, pharmacokinetics and dynamics of treatment with the novel subcutaneous complement inhibitor coversin (nomacopan)