Eculizumab as rescue therapy in a context of dramatic NMOSD attack: report of two cases

Abstract Early administration of plasma exchanges (PE) combined with intravenous methylprednisolone (IVMP) is considered the best treatment for neuromyelitis optica spectrum disorder (NMOSD) attack. However, up to 20% of patients fail to respond, suggesting the existence of idiosyncratic factors yet to be understood. We report cases of two women who suffered devastating Aquaporin-4 immunoglobulin G-positive (AQP4-IgG+) NMOSD attacks, worsening despite optimal treatment up to life-threatening, for which eculizumab was successfully administrated as a rescue therapy. The first case describes a fulminant onset of the disease with pan-medullary and bulbar lesions leading to tetraplegia and respiratory failure within a few days, directly refractory to PE/IVMP. The second case described the 4th attack within two years of an aggressive disease, currently treated with mycophenolate mofetil, with early post-mitoxantrone relapse. For both patients, acute administration of eculizumab immediately after usual treatment failure seemed to have rapidly aborted the inflammatory cascade, saving them from imminent death. In addition to its proven efficacy in preventing relapses in AQP4-IgG + NMOSD, eculizumab could also rapidly stop an attack before the installation of irreversible lesions or death. This raises therapeutic issues relative to the management of such complement inhibitor treatment as rescue therapy, and questions about pathophysiological mechanisms of resistance to PE.