The primary objective of this study is to evaluate the safety and tolerability of sivelestat sodium hydrate administered in combination with standard steroid pulse therapy in patients experiencing an acute NMOSD attack. Safety assessments will include adverse events, laboratory parameters, vital signs, and other clinically relevant findings. In addition, the study will explore whether the addition of sivelestat sodium hydrate to standard steroid pulse therapy improves neurological outcomes in patients with acute NMOSD.
Participants will receive intravenous sivelestat sodium hydrate at a dose of 4.8 mg/kg/day administered as a continuous infusion (0.2 mg/kg/hour) for 5 consecutive days, receive steroid pulse therapy according to the study protocol, and be followed for 28 days after treatment initiation for safety and efficacy evaluations.