Patients with neuromyelitis optica spectrum disorder (NMOSD) may experience severe disability after their incident (first) attack, with disability accumulating with subsequent relapses. Satralizumab, a humanized monoclonal antibody that inhibits the interleukin-6 receptor, reduced relapse frequency and had a favorable safety profile vs placebo in two randomized, placebo-controlled, phase 3 clinical trials in patients with NMOSD: SAkuraSky (satralizumab in combination with baseline immunosuppressants; NCT02028884), and SAkuraStar (satralizumab monotherapy; NCT02073279).
To review a case series of treatment-naïve, aquaporin-4-IgG seropositive (AQP4-IgG+) NMOSD patients who enrolled in SAkuraStar following their incident attack.
All instances of investigator-reported relapse were assessed in six treatment-naïve, AQP4-IgG+ NMOSD patients enrolled in SAkuraStar after their first attack. Relapses that met protocol-defined relapse (PDR) criteria are specified. Patients who experienced a PDR or remained in SAkuraStar when the double-blind period ended were eligible to enter the open-label extension (OLE). Expanded Disability Status Scale (EDSS) scores were recorded at regular intervals and at relapse.
Of the six enrolled patients, two were randomized to placebo, and four to satralizumab. Demographic characteristics in these six patients were generally consistent with the overall SAkuraStar population. One of the two patients who received placebo experienced a PDR on Study Day 21, with a 1.5-point increase in EDSS score, and fully recovered to pre-relapse EDSS score. Two of the four patients who received satralizumab experienced a relapse. The first patient experienced a PDR on Study Day 214, with a 1-point increase in EDSS, and the second patient experienced a relapse (not meeting PDR criteria) on Study Day 458, with a 0.5-point increase in EDSS score. Both patients fully recovered to pre-relapse EDSS score.
Five of six patients continued in the ongoing OLE, and no further relapses were reported (up to March 2020). Safety outcomes were consistent with the overall SAkuraStar safety population.
Treatment-naïve AQP4-IgG+ patients enrolled in SAkuraStar after their incident attack and randomized to placebo experienced a relapse earlier than those randomized to satralizumab. All patients fully recovered to pre-relapse EDSS score. Interpretation is limited due to the small sample size.