Ariceta G, Dixon BP, Kim SH, et al. - Among complement inhibitor-naïve children (under 18 years) with atypical hemolytic uremic syndrome, this phase III, single-arm trial was conducted to assess the efficacy as well as the safety of ravulizumab (a long-acting complement C5 inhibitor engineered from eculizumab). Ravulizumab was given every eight weeks in patients 20 kg and over, and four weeks in patients under 20 kg. A complete thrombotic microangiopathy response (normalization of platelet count and lactate dehydrogenase, and a 25% or more betterment in serum creatinine) through 26 weeks was assessed as the primary endpoint. A complete thrombotic microangiopathy response was achieved by 77.8% of patients, by week 26. No unexpected adverse events, deaths, or meningococcal infections happened. Overall, findings revealed that a rapid improvement in hematologic and kidney parameters was achieved with ravulizumab, without unexpected safety concerns, in complement inhibitor-naïve children suffering from atypical hemolytic uremic syndrome.