Postmarketing safety profile of eculizumab for neuromyelitis optica spectrum disorder: a disproportionality and time-to-onset analysis

Background To evaluate adverse events associated with eculizumab treatment in patients with neuromyelitis optica spectrum disorder (NMOSD) using the US Food and Drug Administration Adverse Event Reporting System (FAERS), thereby providing evidence for clinical risk identification and long-term safety monitoring. Methods Reports related to eculizumab were extracted from the FAERS database from the first quarter of 2004 through the first quarter of 2026. NMOSD cases were identified from reported indications, and only reports listing eculizumab as the primary suspect drug were included. Data cleaning and deduplication were performed in accordance with the procedures recommended by the U.S. Food and Drug Administration. Disproportionality analyses were conducted at the system organ class (SOC) and preferred term (PT) levels using the reporting odds ratio (ROR) and Bayesian confidence propagation neural network (BCPNN) methods. Signal detection was restricted to PTs with at least three reports, followed by clinical priority assessment and time-to-onset analysis. Results A total of 954 adverse event reports were included. The most frequently involved SOCs were general disorders and administration site conditions, nervous system disorders, and musculoskeletal and connective tissue disorders. At the PT level, 27 positive signals were identified, primarily including fatigue, headache, pain, musculoskeletal stiffness, dizziness, and paresthesia. Twelve signals were classified as moderate clinical priority, whereas no strong-priority signals were identified. Among the 152 reports with complete time-to-onset information, the median time to onset was 356 days, and 50.0% of the events occurred more than 360 days after treatment initiation. Conclusion These findings provide new evidence for safety monitoring in patients with NMOSD receiving eculizumab. Further clinical and basic research is warranted to validate these findings.