Ravulizumab in Atypical Hemolytic Uremic Syndrome: An Analysis of 2-Year Efficacy and Safety Outcomes in 2 Phase 3 Trials

Abstract

Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA) caused by complement dysregulation. Ravulizumab is a C5i approved for the treatment of aHUS. This analysis assessed long-term outcomes of ravulizumab in adults and pediatric patients with aHUS. This analysis reports 2-year data from 2 phase 3, single-arm studies. One study included C5i-naïve adults (NCT02949128), and the other included 2 cohorts of pediatric patients (C5i-naïve and those who switched to ravulizumab from eculizumab [pediatric switch patients]; NCT03131219). Patients received intravenous ravulizumab every 4-8 weeks, with the dose depending on body weight. The primary endpoint in the studies of C5i-naïve patients was complete TMA response, which consisted of platelet count normalization, lactate dehydrogenase normalization, and ≥25% improvement in serum creatinine concentrations from baseline, at 2 consecutive assessments≥4 weeks apart. All analyses used descriptive statistics. No formal statistical comparisons were performed. In total, 86 and 92 patients were included in efficacy and safety analyses, respectively. Complete TMA response rates over 2 years were 61% and 90% in C5i-naïve adults and pediatric patients, respectively. The median increase in estimated glomerular filtration rate from baseline was maintained over 2 years in C5i-naïve adults (35mL/min/1.73m2) and pediatric patients (82.5mL/min/1.73m2). Most adverse events and serious adverse events occurred during the first 26 weeks. No meningococcal infections were reported. Improvement in the Functional Assessment of Chronic Illness Therapy - Fatigue score achieved by 26 weeks was maintained over 2 years. Limitations were the small sample of pediatric switch patients and limited availability of genetic data. Long-term treatment with ravulizumab is well tolerated and associated with improved hematologic and renal parameters and quality of life in adults and pediatric patients with aHUS.