The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

Modified intent-to-treat (mIIT) population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity. Participants who received rescue therapy were considered non-responders.

AChR+ population included all participants in the study who were AChR+.

The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity. Participants who received rescue therapy were considered non-responders.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The QMG is a 13-item direct physician assessment scoring system that quantifies disease severity based on impairments of body functions and structures. The 13-items are: ptosis, diplopia, orbicularis oculi weakness, swallowing, speech disruption, percent forced vital capacity, arm and leg endurance (four items), grip strength (two items), and neck flexion strength. Each of the 13 item was quantitatively assessed and scored on a scale from 0=None to 3=Severe, providing a total QMG score (sum of each item score) ranging from 0 to 39 where higher scores indicate greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The QMG is a 13-item direct physician assessment scoring system that quantifies disease severity based on impairments of body functions and structures. The 13-items are: ptosis, diplopia, orbicularis oculi weakness, swallowing, speech disruption, percent forced vital capacity, arm and leg endurance (four items), grip strength (two items), and neck flexion strength. Each of the 13 item was quantitatively assessed and scored on a scale from 0=None to 3=Severe, providing a total QMG score (sum of each item score) ranging from 0 to 39 where higher scores indicate greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The MG-QOL-15r is a disease-specific health-related QoL measure that consists of 15 items: mobility (9 items), symptoms (3 items), and contentment and emotional well-being (3 items). Items were scored on a scale from 0=Not at all to 2=Very much with the total score ranging from 0 to 30 and higher scores indicate worse health-related quality of life (HRQoL).

AChR+ population included all participants in the study who were AChR+.

The MG-QOL-15r is a disease-specific health-related QoL measure that consists of 15 items: mobility (9 items), symptoms (3 items), and contentment and emotional well-being (3 items). Items are scored on a scale from 0=Not at all to 2=Very much, with the total score ranging from 0 to 30 and higher scores indicate worse HRQoL.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The Neuro-QoL is a validated tool designed to evaluate the HRQoL in participants with chronic neurological disease. The Fatigue Subscale is implemented as an eight-item, stand-alone short form that assesses the multi-dimensional aspects of fatigue ranging from general tiredness to debilitating exhaustion that Impacts activities of daily living. Each item was assessed using a 5-level Likert scale ranging between 1=never to 5=always. Raw scores range from 8 to 40, higher values indicate greater fatigue.

AChR+ population included all participants in the study who were AChR+.

The Neuro-QoL is a validated tool designed to evaluate the HRQoL in participants with chronic neurological disease. The Fatigue Subscale is implemented as an eight-item, stand-alone short form that assesses the multi-dimensional aspects of fatigue ranging from general tiredness to debilitating exhaustion that Impacts activities of daily living. Each item was assessed using a 5-level Likert scale ranging between 1=never to 5=always. Raw scores range from 8 to 40, higher values indicate greater fatigue.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The QMG is a 13-item direct physician assessment scoring system that quantifies disease severity based on impairments of body functions and structures. The 13-items are: ptosis, diplopia, orbicularis oculi weakness, swallowing, speech disruption, percent forced vital capacity, arm and leg endurance (four items), grip strength (two items), and neck flexion strength. Each of the 13 item was quantitatively assessed and scored on a scale from 0=None to 3=Severe, providing a total QMG score (sum of each item score) ranging from 0 to 39 where higher scores indicate greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The QMG is a 13-item direct physician assessment scoring system that quantifies disease severity based on impairments of body functions and structures. The 13-items are: ptosis, diplopia, orbicularis oculi weakness, swallowing, speech disruption, percent forced vital capacity, arm and leg endurance (four items), grip strength (two items), and neck flexion strength. Each of the 13 item was quantitatively assessed and scored on a scale from 0=None to 3=Severe, providing a total QMG score (sum of each item score) ranging from 0 to 39 where higher scores indicate greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The MGC is a composite measure consisting of items drawn from the MG-ADL (chewing, swallowing, speech, and breathing), QMG (diplopia and ptosis), and Manual Muscle Test (hip flexion strength, neck, facial, and shoulder abduction) in an effort to include both clinician- and participant-reported elements in a single measure. Each of the ten items contribute to a total score ranging from 0 to 50, with higher values indicating greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The MGC is a composite measure consisting of items drawn from the MG-ADL (chewing, swallowing, speech, and breathing), QMG (diplopia and ptosis), and Manual Muscle Test (hip flexion strength, neck, facial, and shoulder abduction) in an effort to include both clinician- and participant-reported elements in a single measure. Each of the ten items contribute to a total score ranging from 0 to 50, with higher values indicating greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The MGC is a composite measure consisting of items drawn from the MG-ADL (chewing, swallowing, speech, and breathing), QMG (diplopia and ptosis), and Manual Muscle Test (hip flexion strength, neck, facial, and shoulder abduction) in an effort to include both clinician- and participant-reported elements in a single measure. Each of the ten items contribute to a total score ranging from 0 to 50, with higher values indicating greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The MGC is a composite measure consisting of items drawn from the MG-ADL (chewing, swallowing, speech, and breathing), QMG (diplopia and ptosis), and Manual Muscle Test (hip flexion strength, neck, facial, and shoulder abduction) in an effort to include both clinician- and participant-reported elements in a single measure. Each of the ten items contribute to a total score ranging from 0 to 50, with higher values indicating greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

gMG-related exacerbation was defined as one of the following: MG crisis; Substantial symptomatic worsening that requires immediate therapy; or health in jeopardy if rescue therapy is not given.

AChR+ population included all participants in the study who were AChR+.

gMG-related exacerbation was defined as one of the following: MG crisis; Substantial symptomatic worsening that requires immediate therapy; or health in jeopardy if rescue therapy is not given.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The percentage of participants receiving rescue therapy during DBP analyzed the variable that encodes whether a participant received rescue therapy during DBP or not. If a participant stopped the study drug but received rescue therapy during the safety follow-up and this occurred within 24 weeks of baseline then this was counted as having received rescue therapy.

AChR+ population included all participants in the study who were AChR+.

The percentage of participants receiving rescue therapy during DBP analyzed the variable that encodes whether a participant received rescue therapy during DBP or not. If a participant stopped the study drug but received rescue therapy during the safety follow-up and this occurred within 24 weeks of baseline then this was counted as having received rescue therapy.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

The duration was the difference in weeks between the two visits defining the start and end (or Week 24) of reduction from baseline. The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

AChR+ population included all participants in the study who were AChR+.

The duration was the difference in weeks between the two visits defining the start and end (or Week 24) of reduction from baseline. The MG-ADL scale was used to assess the degree of gMG symptoms (six items: diplopia, ptosis, difficulties with chewing, swallowing, talking, and respiratory problems) and functional limitations in carrying out activities of daily living (two items: ability to brush teeth or comb hair and impairment in the ability to arise from a chair) that are present and clinically relevant in gMG participants. Each of the eight items was ranked on a 0-3 scale, with 3 representing the most severe symptoms or impaired performance and 0 representing no symptoms or impaired performance. The total MG-ADL score was calculated as the sum of each item score, with a maximum score ranging from 0 (least severe symptoms/impairment) to 24 (most severe symptoms/impairment). Higher scores indicate greater disease severity.

mIIT population included all participants that were part of the ITT and had a baseline and at least one post-baseline MG-ADL assessment during the DB period. This excludes adolescents who joined the study after the last adult participant was randomized.

An AE was any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution. An AE can be any unfavorable and unintended sign (including an abnormal laboratory finding), symptoms, or disease temporarily associated with the use of a medicinal product, whether or not considered related to the medicinal product.

Safety-evaluable (SE) population included all enrolled participants who received at least one dose of study drug, with participants grouped according to treatment received.

SE Population included all enrolled participants who received at least one dose of study drug, with participants grouped according to treatment received. Overall number of participants analyzed is the number of participants with data available for analyses. Number analyzed is the number of participants with data available for analyses at the specified timepoints.

SE Population included all enrolled participants who received at least one dose of study drug, with participants grouped according to treatment received. Number analyzed is the number of participants with data available for analyses at the specified timepoints.

The percentage of ADA-positive participants after drug administration were determined for participants exposed to satralizumab. For determining post-baseline incidence, participants were considered to be ADA-positive if they were ADA-negative or had missing data at baseline but developed an ADA response following study drug exposure, or if they were ADA-positive at baseline and the titer of 1 or more post-baseline samples was at least 0.60 titer units (t.u.) greater than the baseline titer result. Participants were considered to be ADA-negative if they were ADA-negative or had missing data at baseline and all post-baseline samples were negative, or if they were ADA positive at baseline but did not have any post-baseline samples with a titer that is at least 4-fold (0.60 titer unit) greater than the titer of the baseline sample.

Immunogenicity-analysis population included all participants randomly assigned to study treatment who received any study treatment with at least one post-dose anti-drug antibody (ADA) assessment. Overall number analyzed is the number of participants with data available for analysis.

Pharmacokinetic (PK)-evaluable population included all participants randomly assigned to study treatment who received at least one dose and had sufficient sampling to permit PK evaluation. Number analyzed is the number of participants with data available for analysis at the specified timepoints.