Atypical Hemolytic Uremic Syndrome Treated With Ravulizumab or Eculizumab: A Claims-Based Evaluation of Health Care Resource Utilization and Clinical Outcomes in the United States

Effectiveness and safety of ravulizumab for Japanese patients with atypical hemolytic uremic syndrome switched from eculizumab: an analysis of a post-marketing surveillance

BACKGROUND

Ravulizumab, a long-acting anti-C5 antibody, was approved for atypical hemolytic uremic syndrome (aHUS) in September 2020 in Japan. Post-marketing surveillance was mandated by local regulatory authorities to evaluate the effectiveness and safety of ravulizumab in patients with aHUS in real-world clinical practice.

METHODS

Patients with aHUS who switched from eculizumab to ravulizumab and received at least one dose of ravulizumab between September 2020 and December 2021 were enrolled. The effectiveness was evaluated by thrombotic microangiopathy (TMA) event-free status, defined as no sign of TMA recurrence and no initiation of plasma therapy/dialysis during ravulizumab treatment. The safety of ravulizumab was evaluated by summarizing the incidence of adverse events (AEs) and serious AEs.

RESULTS

This study included 33 patients (19 children and 14 adults). The median (range) duration of eculizumab treatment before the switch was 1233 (113-3240) days, and the duration of ravulizumab treatment was 351 (127-365) days. During ravulizumab treatment, TMA event-free status was achieved in 97.0% (32/33) of patients. The platelet count, lactate dehydrogenase levels, and serum creatinine levels remained stable during ravulizumab treatment. Twenty-nine AEs were reported in 13 patients, including nine serious AEs in seven patients. No meningococcal infections or deaths occurred during ravulizumab treatment. One patient discontinued treatment and died 478 days later from an unknown cause.

CONCLUSIONS

This study confirmed the effectiveness and safety of ravulizumab in Japanese patients with aHUS after switching from eculizumab in a real-world setting.

Global aHUS Registry Analysis of Patients Switching to Ravulizumab From Eculizumab

Introduction

Atypical hemolytic uremic syndrome (aHUS) is a progressive rare disease that, if untreated, can result in severe organ damage and death. Ravulizumab, a next-generation terminal complement inhibitor, provides immediate, complete, and sustained complement C5 inhibition. Real-world data in patients with aHUS who switched to ravulizumab from eculizumab are lacking.

Methods

The Global aHUS Registry is a multicenter study (NCT01522183) collecting data on adult or pediatric patients with an aHUS diagnosis, regardless of treatment. Patient characteristics, genetic data, hematological and renal parameters, clinical events (e.g., dialysis and kidney transplantation), and adverse events (AEs) were extracted from patients who switched to ravulizumab from eculizumab up to July 3, 2023.

Results

Overall, 60 patients switched to ravulizumab (adult: n = 43; pediatric: n = 17); 11 patients were excluded from effectiveness and genetic analyses (N = 49; adult: n = 40; pediatric: n = 9) because they received <3 months ravulizumab treatment and/or had >1 month between eculizumab discontinuation and ravulizumab initiation. Pathogenic complement variants were identified in 11 of 49 patients (22%); the most common was a complement factor H variant (n = 5/49 [10%]). During ravulizumab treatment, 20 AEs occurred in 13 patients, with no unexpected AEs and only 3 treatment-related AEs (infusion reaction, headaches, and fatigue). No meningococcal infections or deaths were reported. No new events of dialysis, kidney transplantation, or thrombotic microangiopathy were reported. Renal and hematological parameters remained stable after switching to ravulizumab.

Conclusion

This is the first real-world cohort analysis of data from patients treated with ravulizumab and reinforces the real-world safety and effectiveness data of ravulizumab in patients with aHUS who switched from eculizumab.

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 m2) and pediatric patients (82.5 mL/min/1.73 m2). 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.

Ravulizumab facilitates reduced burden of vascular access, a major benefit in paediatric atypical haemolytic uraemic syndrome

BACKGROUND

Atypical haemolytic uraemic syndrome (aHUS) is a rare thrombotic microangiopathy resulting from dysregulation of the alternative complement pathway, leading to multi-organ dysfunction and chronic kidney disease. Eculizumab is an anti-C5 monoclonal antibody therapy that has significantly improved aHUS disease control and patient outcomes, however it requires fortnightly intravenous dosing. This often necessitates long term central access and a high hospital attendance burden. Ravulizumab is a novel, next-generation anti-C5 monoclonal antibody engineered from eculizumab to reduce endosomal degradation of the antibody, increasing the dosing interval up to 8 weeks.

CASE SERIES

In this retrospective case series we present the transition of three children with aHUS from eculizumab to ravulizumab from a single tertiary paediatric nephrology service. All patients underwent genomic and immunological work up for aHUS, with no cause found. After stabilisation with eculizumab, two patients developed macrovascular thrombotic complications associated with indwelling central vascular catheters, ultimately leading to central access failure. All patients were transitioned from eculizumab to ravulizumab without relapse of aHUS. One patient successfully underwent deceased donor kidney transplantation with ravulizumab for complement inhibition. All patients have transitioned to peripheral access for infusions given the reduced frequency of dosing, maintaining good control of aHUS for 2-4 years.

CONCLUSION

Ravulizumab permits sufficiently reduced frequency of infusion to allow for administration by peripheral cannulation - removing the risks of long term central vascular access often required to deliver eculizumab to paediatric patients.