The Efficacy of Eculizumab in the Acute Phase of Neuromyelitis Optica Spectrum Disorder: A Case Series Study.

Eculizumab, a monoclonal antibody against complement C5, has been approved to prevent neuromyelitis optica spectrum disorder (NMOSD) relapse. Although complement activation leads to neuroinflammation and tissue necrosis in NMOSD attacks, clinical reports on the efficacy of eculizumab in the acute phase of NMOSD are limited. To clarify its effectiveness against clinical symptoms in NMOSD attacks, we described five patients with NMOSD who were administered eculizumab soon after treatment for an attack. The patients included four female patients and one male patient aged 50-93 years. The index attacks were optic neuritis in three cases, myelitis in one case, and brainstem encephalitis and myelitis in one case. Three patients had not received any maintenance therapy. Although all patients had received intravenous methylprednisolone (IVMP) and plasma exchange (PE) several times, these treatments were not sufficient to improve their symptoms. Thereafter, eculizumab was initiated between 35 and 61 days after the attack onset and partially ameliorated the symptoms in all cases. These cases suggest eculizumab as a treatment option to lessen the symptoms of severe NMOSD attacks, although the efficacy of IVMP and PE before eculizumab administration cannot be excluded.