Efficacy and safety of satralizumab in neuromyelitis optica spectrum disorder (NMOSD): Results from open-label extension periods of SAkuraSky and SAkuraStar

Abstract

Purpose : Satralizumab, a humanized, monoclonal recycling antibody that targets the interleukin-6 receptor, reduced patients’ risk of NMOSD relapse in the double-masked (DM) periods of two randomized, phase 3 clinical trials: SAkuraSky (satralizumab in combination with baseline immunosuppressants; NCT02028884), and SAkuraStar (satralizumab monotherapy; NCT02073279). We assessed the efficacy and safety of satralizumab over a longer period of treatment, using data from the SAkura studies’ open-label extension (OLE) periods.

Methods : Patients entering SAkuraSky/Star were randomized to receive satralizumab 120 mg or placebo at Weeks 0, 2, 4, and Q4W thereafter. After completing the DM period or experiencing a relapse, patients could enter the OLE period. Time to first investigator-assessed protocol-defined relapse (PDR) and safety were evaluated in the combined DM+OLE periods, using a pooled population from both studies. Data were analyzed through the clinical cut-off date (June 2019).

Results : Overall, 179 patients were randomized to treatment (satralizumab n=105; placebo n=74), of whom 166 received ≥1 dose of satralizumab in the combined DM+OLE period. The median (range) satralizumab exposure in the DM period was 96.1 (8–224) weeks, and in the combined DM+OLE was 131.9 (13–276) weeks. In the combined DM+OLE, patients originally randomized to satralizumab had a 51% lower risk of investigator-assessed 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, which likely reduced the observed treatment difference between satralizumab and placebo compared with the DM period. No patients randomized to satralizumab withdrew from the OLE period due to a relapse, vs four patients who were originally randomized to placebo. Safety profiles in the combined DM+OLE were consistent with those in the DM period (Table). No deaths were reported.

Conclusions : In the DM and OLE periods of the SAkura studies, patients receiving satralizumab had a significantly reduced risk of relapse vs placebo. Satralizumab was well-tolerated and showed a favorable safety profile.

This is a 2021 ARVO Annual Meeting abstract.