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P0711 - Efficacy of satralizumab in neuromyelitis optica spectrum disorder (NMOSD): Results from open-label extension periods of SAkuraSky and SAkuraStar (ID 1319)
Satralizumab, a humanized, monoclonal recycling antibody that targets the interleukin-6 receptor, reduced patients’ risk of NMOSD relapse in the double-blind (DB) periods of two randomized, phase 3 clinical trials in NMOSD: SAkuraSky (satralizumab in combination with baseline immunosuppressants; NCT02028884), and SAkuraStar (satralizumab monotherapy; NCT02073279).
To assess the efficacy of satralizumab over a longer period of treatment, using data from the SAkura studies’ open-label extension (OLE) periods.
Patients entering SAkuraSky/Star were randomized to receive satralizumab 120mg or placebo at Weeks 0, 2, 4, and Q4W thereafter. After completing the DB period or experiencing a relapse, patients could enter the OLE period (same satralizumab dosing as DB period). The primary endpoint of both studies was time to first protocol-defined relapse (PDR) in the DB period, adjudicated by a Clinical Endpoint Committee (CEC). In this analysis, which includes OLE data (CEC adjudication unavailable), we assessed time to first investigator-reported PDR (any relapse considered by the investigator to meet PDR criteria) in the combined DB+OLE periods, using a pooled population from both studies.
Overall, 179 patients were randomized to treatment (satralizumab n=105; placebo n=74), of whom 166 received ≥1 dose of satralizumab in the combined DB+OLE period. The median (range) satralizumab exposure in the DB period was 96.1 (8–224) weeks, and in the combined DB+OLE was 131.9 (13–276) weeks.
In the combined DB+OLE, patients originally randomized to satralizumab had a 51% lower risk of investigator-reported PDR vs those originally randomized to placebo (HR [95% CI] 0.49 [0.31–0.79]; P=0.002); the risk reduction was more pronounced in AQP4-IgG seropositive patients (66% risk reduction; HR [95% CI] 0.34 [0.19–0.62]; P<0.001). Patients who switched from placebo to satralizumab upon entry into the OLE period were included in the placebo group for this analysis, which likely reduced the observed treatment difference between satralizumab and placebo compared with the DB period.
No patients randomized to satralizumab withdrew from the OLE period due to a relapse, vs four patients who were originally randomized to placebo. The safety profile of satralizumab in the OLE was consistent with the DB period.
Across the DB and OLE periods of the SAkura studies, patients randomized to satralizumab had a significantly reduced risk of relapse vs placebo.