Abstract
INTRODUCTION: Atypical hemolytic uremic syndrome (aHUS) is a potentially life-threatening condition associated with poor clinical outcomes if not treated adequately. Eculizumab has become the standard of care, whereas ravulizumab, a second-generation, high-affinity complement C5 inhibitor, demonstrates comparable efficacy in improving renal function, hematological markers, and dialysis rates. In addition, ravulizumab offers practical advantages, including a longer dosing interval and immediate, complete, and sustained inhibition of free C5, making it a valuable therapeutic option. METHODS: Given the limited real-world experience with ravulizumab, we present a case series of six treatment-naïve aHUS patients who received ravulizumab as first-line therapy. RESULTS: These cases include one pregnancy-related aHUS, one postpartum case, one related to a urinary tract infection, one associated with hypertension, one with a pneumonia-related trigger, and one kidney transplant patient with a prior verotoxin-producing E. coli infection. Altogether, these cases illustrate the challenges in diagnosing aHUS. The choice to administer ravulizumab as first-line treatment was sometimes made in the presence of a clear clinical suspicion, even when not all minor criteria seemed to confirm the diagnosis. In most patients, renal function improved rapidly after ravulizumab administration, followed by recovery of hematological parameters, which were stable in the longer term. As improvements remained sustained over time, the possibility of discontinuing ravulizumab can be evaluated on a case-by-case basis. CONCLUSION: These cases highlight the importance of early diagnosis, prompt intervention, and multidisciplinary care in managing aHUS. Ravulizumab as first-line therapy proved effective and well-tolerated, with sustained clinical improvements observed across diverse real-world scenarios.