Abstract Details

Satralizumab reduced the risk of protocol-defined relapse (PDR) and severe PDR vs placebo in the double-blind periods (DBP) of two phase 3 trials in patients with NMOSD: SAkuraSky (NCT02028884; satralizumab + baseline immunosuppressants [IST]) and SAkuraStar (NCT02073279; satralizumab monotherapy).

Patients who completed the DBPs and open-label extensions (OLEs) of SAkuraSky and SAkuraStar were rolled-over into a single-arm, open-label study (SAkuraMoon [NCT04660539]) and continued receiving satralizumab 120mg Q4W +/- IST; we evaluated all AQP4-IgG+ adults (≥18 years) who received ≥1 dose of satralizumab during these studies (data cut-off: 31 January 2022).

PDRs in the DBPs were adjudicated by a Clinical Endpoint Committee; however, PDRs in the OLEs and SAkuraMoon were determined by the investigator (iPDRs). We evaluated the annualized iPDR rate (ARR), time to first iPDR, severe iPDR (≥2 point increase in the Expanded Disability Status Scale [EDSS] score), and sustained EDSS worsening (EDSS increase of ≥2, ≥1, or ≥0.5 points for patients with baseline scores of 0, 1–5, or ≥5.5, respectively, confirmed ≥24 weeks post-initial-worsening).

Overall, 106 AQP4-IgG+ adults were included. The median (range) duration of satralizumab exposure was 5.0 (0.1–7.9) years. The overall adjusted ARR (95% CI) was 0.09 (0.06–0.12). When assessed longitudinally, the ARR did not increase with additional years of exposure (Y1: 0.16 [0.09–0.27]; Y2: 0.10 [0.05–0.20]; Y3: 0.05 [0.01–0.15]; Y4: 0.07 [0.02–0.26]). At Week 240 (4.6 years), 72% (95% CI: 62–80%) of satralizumab-treated patients were free from iPDR, 91% (84–96%) were free from severe iPDR, and 85% (75–91%) had no sustained EDSS worsening.

These results demonstrate that the efficacy of satralizumab observed in the DBPs is sustained with long-term treatment. High proportions of patients remained free from relapse, severe relapse, or worsening disability, with a consistently low ARR over 4.6 years of satralizumab exposure.