#1028 Experience with ravulizumab in atypical hemolytic uremic syndrome

Abstract Background and Aims The arrival of eculizumab revolutionized the treatment of Atypical Hemolytic Uremic Syndrome (aHUS). Ravulizumab also offers C5 inhibition, but with 3-4 times longer half- life. We describe the experience with ravulizumab in patients with aHUS in two scenarios: 1. Switching from another C5 inhibitor in stable patients; 2. Direct initiation of therapy with ravulizumab (naïve). Method We present 9 patients with an average age of 42 ± 13 years and weight of 81 ± 12.4 kg. The switch to ravulizumab was initiated 2 weeks after the last dose of eculizumab in switch patients, while in naïve patients it was initiated after excluding other causes of aHUS. The initial dose was 2700 mg, followed by a second dose of 3300 mg after 2 weeks, and subsequently every 2 months. Analytical variables of renal function, hematological parameters, and complement were collected. Results Switch : 6 patients (50% females), 4/6 were transplant recipients (3 on prophylactic treatment). Regarding renal function, 5/6 patients had a complete response with eculizumab (creatinine 1.33 ± 0.32 mg/dL, eGFR 59.5 ± 34.3 mL/min/1.73 m2, proteinuria 115 ± 91.5 mg/g), and all of them had a complete hematological response. After the switch, all patients maintained a complete hematological response, stability of renal function, and serum complement levels. Naïve : 3 cases (2 males); 2/3 required hemodialysis (HD) at presentation. The renal response was complete in two patients and partial in the third (who discontinued HD after 90 days and currently remains stable with stage G3b chronic kidney disease). All three patients had a complete hematological response. Only 3 adverse effects were documented (arthralgia, headache, and rhinitis), with no cases of infection. Conclusion The use of ravulizumab is effective both in maintaining a complete response after switching from eculizumab and as a first-line therapy. The safety profile is comparable, with the main difference being the dosing regimen, as ravulizumab requires fewer administrations and leads to a reduction in direct and indirect costs.