Satralizumab in the treatment of neuromyelitis optica spectrum disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and debilitating autoimmune astrocytopathy with a predominantly relapsing disease course. Satralizumab, a humanized monoclonal antibody, was designed to treat NMOSD by targeting the IL-6 receptor. Satralizumab builds on positive experiences of off-label use tocilizumab in recent years. Before 2019, no medications were approved for the treatment of NMOSD. In 2020, satralizumab became the third compound to enter the US market, adding to the complement inhibitor eculizumab and the CD19 inhibitor inebilizumab. Here, we review the two randomized, double-blind, Phase III trials that investigated the subcutaneous administration of satralizumab as add-on treatment and monotherapy. Both studies revealed positive effects concerning the reduction of relapse risk for AQP4 seropositive NMOSD patients and generally good tolerability.