Real-world management of patients with neuromyelitis optica spectrum disorder using satralizumab: Results from a Japanese claims database

Background Satralizumab, a humanized anti-interleukin-6 receptor monoclonal antibody, has been approved globally for the treatment of neuromyelitis optica spectrum disorder (NMOSD), based on positive results from two randomized, double-blind, phase 3 studies: SAkuraSky (NCT02028884) and SAkuraStar (NCT02073279). There remains an unmet need to understand the real-world management of NMOSD, especially in patients undergoing tapering of concomitant therapy. We examined real-world treatment patterns, including concomitant glucocorticoids and immunosuppressants, and relapse in satralizumab-treated patients with NMOSD, using a Japanese administrative hospital claims database. Methods We used retrospective data from the Medical Data Vision hospital-based administrative claims database. The index date was the date of first satralizumab prescription and the study period was set between August 2018 and March 2022. Patients were included in the overall population if they had a first prescription for satralizumab between August 2020 and March 2022, an International Classification of Disease, Version10 code of G36.0 prior to March 2022, and were observable for ≥90 days prior to the index date. The primary endpoint was the percentage of patients with relapse-free reduction of oral glucocorticoids to 0 mg/day at 360 days of continued satralizumab treatment. Secondary endpoints included time to relapse, number of relapses after the index date while being on continuous satralizumab treatment, annualized relapse rate before and after the index date, and concomitant medication use. Relapse and dose reduction were identified using definition specifically developed for this study. Results Of the 131 patients included in the overall population, most were female (90.8%), aged 18–65 years (75.6%), and were prescribed oral glucocorticoids (93.1%). Azathioprine (19.1%) and tacrolimus, a calcineurin inhibitor (18.3%), were the most common immunosuppressants at index date. Six (4.6%) patients had a history of biologic use (tocilizumab, 1 0.8%; eculizumab, 5 3.8%). Among 111 patients observable for 360 days pre-index, there were 0.6±0.8 (mean±SD) relapses during 360 days before the index date. The median (interquartile range) duration of satralizumab exposure was 197.0 (57.0–351.0) days. Most (125/131; 95.4%) of patients were relapse-free post-index; 6 (4.6%) patients relapsed within 90 days after the index date; of which 2 had the first relapse within 7 days after the index date. Among 21 patients with 360-day follow-up, 6 (28.6%) patients were on 0 mg/day dose of glucocorticoid prescription without relapse 360 days post-index. Of these 6 patients, 2 had no prescription of oral glucocorticoids at the index date and remained glucocorticoid- and relapse-free 360 days after the index date. Conclusion These real-world data support the phase 3 clinical trials. Our results, over a median duration of satralizumab exposure was of 197.0 days, showed that a majority (125/131, 95.4%) of patients were relapse-free after initiating satralizumab treatment. The number of glucocorticoid-free patients without relapse increased over time under continuous satralizumab prescription. Further studies are needed to confirm if satralizumab can be used as a potential immunosuppressant- and glucocorticoid-sparing agent.