Simulation of eculizumab concentration-time profiles. Eculizumab concentration-time profiles over 7 days after the first dose were simulated based on our developed models for nonbleeding and bleeding patients shown in Table 2. The population PK parameter estimates were used for the simulations. Eculizumab concentration-time curves are shown in different colors and represent different predose sC5b-9 levels ranging from 200 to 800 ng/mL. The horizontal dotted pink line represents the suggested eculizumab target concentration of 100 μg/mL.