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

Rationale & Objective: 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.

Study Design: This analysis reports 2-year data from 2 phase 3, single-arm studies.

Setting & Participants: 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).

Exposure: Patients received intravenous ravulizumab every 4-8 weeks, with the dose depending on body weight.

Outcomes: 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.

Analytical Approach: All analyses used descriptive statistics. No formal statistical comparisons were performed.

Results: 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 (35 mL/min/1.73 m) and pediatric patients (82.5 mL/min/1.73 m). 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: Limitations were the small sample of pediatric switch patients and limited availability of genetic data.

Conclusions: 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.