A Study In Neuromyelitis Optica Spectrum Disorder (NMOSD) With Satralizumab As An Intervention

Percentage of Participants in Need of Rescue Therapy Due to Relapse

Relapse was the occurrence of new or worsening neurological symptoms attributable to NMOSD. New or worsening neurological symptoms that occur \<31 days following the onset of a relapse were considered part of the same relapse. The severity of relapses was assessed based on the need of rescue therapy. Rescue therapy for clinical relapse included pulse intravenous (IV) corticosteroids, oral corticosteroids for tapering, intravenous immunoglobulin (IVIG) and/or apheresis (including plasma exchange and plasmapheresis).

Time frame: Up to 14 months

Percentage of Participants in Need of Plasma Exchange Due to Relapse

Relapse was the occurrence of new or worsening neurological symptoms attributable to NMOSD. New or worsening neurological symptoms that occur \<31 days following the onset of a relapse were considered part of the same relapse. The severity of relapses was assessed based on the need for plasma exchange.

Time frame: Up to 14 months

Percentage of Participants With Residual Disability Due to Relapse

Relapse was the occurrence of new or worsening neurological symptoms attributable to NMOSD. New or worsening neurological symptoms that occur \<31 days following the onset of a relapse were considered part of the same relapse.

Time frame: Up to 14 months

Change From Baseline in Expanded Disability Status Scale (EDSS) Score

EDSS was a quantitative measure of disability and for assessment of severity of relapse for participants with NMOSD. The overall score ranges from 0 points (normal neurological examination) up to 10 points (death), increasing in increments of 0.5 points. Higher scores represent increased disability. A negative change from baseline indicates improvement.

Time frame: Up to Week 36

Time to Onset of Confirmed Disability Progression (CDP) Sustained for at Least 12 Weeks

EDSS was a quantitative measure of disability and for assessment of severity of relapse for participants with NMOSD. The overall score ranges from 0 points (normal neurological examination) up to 10 points (death), increasing in increments of 0.5 points. Higher scores represent increased disability. CDP was defined as 1-point or greater worsening in EDSS from baseline that is not attributable to another etiology when the baseline score is 5.5 or less, and ≥ 0.5 when the baseline score is above 5.5. Disability progression was considered confirmed when the increase in the EDSS is confirmed at a regularly scheduled visit at least 12 weeks after the initial documentation of neurological worsening.

Time frame: Up to 12 weeks

Change From Baseline in the Symbol Digital Modalities Test (SDMT)

SDMT testing was to detect impairment of key neurocognitive functions that underlie many substitution tasks, including sustained attention, visual scanning, and recent memory. The test consisted of a sequence of 110 symbols displayed in a maximum 90 seconds and a reference key legend with 9 symbols in a given order and their respective matching digits from 1 to 9. The test measures the speed (number of correct paired responses) to pair abstract symbols with specific digits in 90 seconds time. The score is the number of correctly paired items in 90 seconds with a maximum score of 110 and minimum of 0. Higher scores indicate improvement.

Time frame: Baseline, Week 24

Change in High Contrast (100%) and Low Contrast (2.5%) Visual Acuity Using High-and Low-contrast Letter Acuity (LCLA) Charts

Best corrected high-contrast (100%) and low-contrast (2.5%) visual acuities were measured at distances of both 4 and 1 meters with the appropriate eye charts. Each eye was tested individually. No visual acuities were obtained with both eyes open. The participants read the charts from left to right starting with the top line (largest letters). The participants proceeded to each lower line until he/she could not see the letters. The total number of letters read correctly were recorded for each eye. Visual acuity was measured before any drops are instilled into the eye and before OCT assessments.

Time frame: Baseline and Week 24

Change in Visual Functioning Questionnaire -25 (VFQ-25)

The National Eye institute (NEI) VFQ-25 captures a participants's perception of vision-related functioning and vision-related quality of life. The core measures include 25 items that comprise 11 vision-related subscales and one item on general health. The NEI VFQ-25 also included an appendix of additional items that was used to expand the scales up to 39 total items. The composite score and the subscale scores range from 0 to 100, with higher scores indicating better vision-related functioning.

Time frame: At Week 24

Time to Onset of Confirmed Disability Progression (CDP) Sustained for at Least 24 Weeks

EDSS was a quantitative measure of disability and for assessment of severity of relapse for participants with NMOSD. The overall score ranges from 0 points (normal neurological examination) up to 10 points (death), increasing in increments of 0.5 points. Higher scores represent increased disability. CDP was defined as 1-point or greater worsening in EDSS from baseline that is not attributable to another etiology when the baseline score is 5.5 or less, and ≥ 0.5 when the baseline score is above 5.5. Disability progression was considered confirmed when the increase in the EDSS is confirmed at a regularly scheduled visit at least 12 weeks after the initial documentation of neurological worsening.

Time frame: Up to 24 weeks