In 4 PNH patients with inadequate response to C5 inhibitors who have completed 48 weeks of treatment (out of 6 enrolled), BCX9930 given initially as add‐on and then as monotherapy (3 out 4 patients) increased hemoglobin level from mean 8.91 gr/dl at baseline to mean 11.60 gr/dL at week 48, with no need of transfusion during the treatment period.99, 100. Here, C5 is linked to paroxysmal nocturnal hemoglobinuria.