ABSTRACT
Background: Severe presentation of ANCA vasculitis is a life-threatening disease despite aggressive immunodepression therapy. Complement hyperactivation is involved in pathogenesis;thus, the effect of the C5 inhibitor (eculizumab) used in severe forms of ANCA vasculitis may be a treatment option. Method(s): This is a retrospective study. Nine patients were included. Period of study: from May 2017 to May 2022. All patients received at least 3 drugs (steroids, rituximab and mycophenolate or cyclophosphamide) before eculizumab. Eculizumab was indicated as an off-label indication due to lack of improvement or clinical worsening. Result(s): Mean (SD) age: 62 (15) years. Female: 4. Three patients showed serum antiproteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) and 5 (myeloperoxidase: MPO-ANCA) and one was ANCA-negative. Six patients had an estimated glomerular filtration rate (eGFR) < 10 ml/min/1.73 m2 at presentation. Five patients had pulmonary involvement. The mean (min-max) time of follow-up after the onset of eculizumab was 27 (1-60) months. One patient ANCA-negative microscopic polyangiitis with diffuse alveolar hemorrhage needed orotracheal intubation and had a satisfactory evolution after eculizumab;however, 20 days after, the patient developed a COVID-19 infection and died. One patient who needed urgent dialysis at presentation did not recover renal function and showed a complement factor H mutation. The evolution of the other 7 patients was as follows: the median (p25-p75) eGFR increased from baseline to the end of the follow-up: 9.1(4.8-21.7)ml/min/1.73m2 to 31(13-45)ml/min/1.73m2, respectively (P=0.018) and the mild proteinuria disappeared in all patients. Alveolar hemorrhage improved in all patients within seven days after the first eculizumab administration. The median (p25-p75) doses of eculizumab administered were 1800(1800-3600) mg. One patient required eculizumab for two different periods. Conclusion(s): One patient died due to a COVID-19 infection, and one remained in chronic renal replacement therapy. Alveolar hemorrhage was well controlled in all patients. The eGFR increased significantly in 7/9 patients, and in 4/6 patients, dialysis could be withdrawn. In severe ANCA vasculitis, eculizumab should be considered for improving outcomes.