All together, these data demonstrate that ALN-CC5 monotherapy may result in suboptimal control of intravascular hemolysis in PNH; on the other hand, once used in combination with eculizumab, ALN-CC5 allows for more effective C5 inhibition, which has not been seen so far with anti-C5 mAb. Here, C5 is linked to paroxysmal nocturnal hemoglobinuria.