Predictors of hemolysis in patients with and without hemolysis events. Assessment of key characteristics of higher disease activity at PEGASUS study baseline in patients with and without hemolysis events include higher-than-label eculizumab dose at screening (>900 mg every 2 weeks), ≥4 transfusions within 12 months before study entry, and detectable CH50 levels while on eculizumab treatment. CH50, total complement function; ECU, eculizumab.