A Study To Evaluate Efficacy, Safety, Pharmacokinetics, And Pharmacodynamics Of Satralizumab In Patients With Generalized Myasthenia Gravis

Study Overview
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Brief Summary
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This study will evaluate the efficacy, safety, pharmacokinetics, and pharmacodynamics of satralizumab compared with placebo in participants with generalized myasthenia gravis (gMG).

Official Title
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A Phase III, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study To Evaluate Efficacy, Safety, Pharmacokinetics, And Pharmacodynamics Of Satralizumab In Patients With Generalized Myasthenia Gravis

Conditions
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Generalized Myasthenia Gravis

Intervention / Treatment
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* Drug: Satralizumab
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Signed Informed Consent Form For adolescent patients: Informed Consent Form for study participation signed by the parents or a legal guardian, and patient assent obtained, as per local requirements Ability to comply with the study protocol procedures Confirmed diagnosis of gMG (anti-AChR, anti-MuSK or anti-LRP4 present at screening) A total MG-ADL score of ≥ 5 points at screening with more than 50% of this score attributed to non-ocular items MGFA severity Class II-IV Ongoing gMG treatment at a stable dose For female patients of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use adequate contraception during the treatment period and for at least 3 months after the final dose of satralizumab. Exclusion Criteria: History of thymectomy within 12 months prior to screening Ocular MG (MGFA Class I) and myasthenic crisis (MGFA Class V) within the last 3 months prior to screening Known disease other than gMG that would interfere with the course and conduct of the study Positive screening tests for hepatitis B virus (HBV) and hepatitis C virus (HCV) Evidence of latent or active tuberculosis (excluding patients receiving chemoprophylaxis for latent tuberculosis infection) Receipt of live or live attenuated vaccine within 6 weeks prior to baseline Pregnant or breastfeeding, or intending to become pregnant during the study or within 3 months after the last dose

Ages Eligible for Study
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Minimum Age: 12 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Satralizumab<br>Participants will receive Satralizumab at Weeks 0, 2, 4, and Q4W thereafter. Adolescent patients who first enter the study in the OLE period will receive satralizumab SC loading doses at Week 0, 2, and 4 in the OLE, followed by maintenance doses Q4W thereafter and will remain on stable background therapy until Week 24 of the OLE. | Drug: Satralizumab<br>* Satralizumab will be administered as a subcutaneous injection<br>|
| Placebo Comparator: Placebo<br>Participants will receive placebo at Weeks 0, 2, 4, and Q4W thereafter | Other: Placebo<br>* Satralizumab placebo will be administered as a subcutaneous injection<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean change from baseline in Myasthenia Gravis Activities of Daily Living (MG-ADL) score in AChR-antibody seropositive population |  | Week 24 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean change from baseline in Quantitative Myasthenia Gravis (QMG) score |  | Week 24 | 
| Mean change from baseline in Myasthenia Gravis Quality of Life 15 Scale (MG-QOL 15r) score |  | Week 24 | 
| Mean change from baseline in Quality of Life in Neurological Disorders (Neuro-QoL) Fatigue Subscale score |  | Week 24 | 
| Mean change from baseline in total Myasthenia Gravis Composite (MGC) score |  | Week 24 | 
| Proportion of MG-ADL responders |  | Week 24 | 
| Proportion of QMG responder |  | Week 24 | 
| Proportion of MGC responders |  | Week 24 | 
| Proportion of participants who have achieved minimal disease manifestation (total MG-ADL score of 0 or 1) |  | Week 24 |