A Phase 3 Open-Label Study of Eculizumab in Pediatric Participants With Refractory Generalized Myasthenia Gravis (gMG)
Condition: Myasthenia Gravis; Myasthenia Gravis, Juvenile Form; Myasthenia Gravis, Generalized
MeSH terms: Myasthenia Gravis; Muscle Weakness
Intervention: Eculizumab
Intervention description: Eculizumab will be administered by IV infusion.
Intervention MeSH terms: Eculizumab
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Intervention model: Single Group Assignment
Masking: None (Open Label)
Enrollment: 11.0
Sex: All
Minimum age: 6 Years
Maximum age: 17 Years
Healthy volunteers: No
Keywords: Myasthenia Gravis; Myasthenia Gravis, Generalized

Summary:

      The purpose of this study is to evaluate the efficacy, safety, pharmacokinetics, and
      pharmacodynamics of eculizumab in the treatment of pediatric refractory gMG based on change
      from Baseline in the Quantitative Myasthenia Gravis (QMG) score for disease severity.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Male or female pediatric participants 6 to <18 years of age at time of assent/consent.

          -  Vaccinated against Neisseria meningitidis.

          -  Documented vaccination against Haemophilus influenzae and Streptococcus pneumoniae
             infections prior to dosing as per local and country specific immunization guidelines
             for the appropriate age group.

          -  Diagnosis of MG confirmed by positive serologic test for anti-acetylcholine receptor
             antibodies at Screening, and 1 of the following: (a) history of abnormal neuromuscular
             transmission test demonstrated by single-fiber electromyography or repetitive nerve
             stimulation; (b) history of positive anticholinesterase test (for example, edrophonium
             chloride or neostigmine test); or (c) participant demonstrated improvement in MG signs
             on oral acetylcholinesterase inhibitors, as assessed by the Investigator.

          -  Presence of refractory gMG, defined as participants with gMG who have 1 or more of the
             following: (a) failed treatment ≥1 year with at least 1 immunosuppressive therapies
             (IST), defined as follows: (1) persistent weakness with impairment of activities of
             daily living; (2) myasthenia gravis (MG) exacerbation and/or crisis while on
             treatment; or (3) intolerance to ISTs due to side effect or comorbid condition(s). (b)
             Require maintenance plasma exchange (PE) or intravenous immunoglobulin (IVIg) to
             control symptoms; and/or (c) in the opinion of the Investigator, MG poses a
             significant functional burden despite current MG treatment.

          -  MGFA Clinical Classification of Class II to IV at Screening.

          -  In patients aged 12 to 18 years, QMG total score ≥ 12 at Screening; in patients aged 6
             to 11 years, no minimum QMG is required for inclusion; however, patients must have
             documented limb weakness in at least one limb.

          -  All MG-specific treatment has been administered at a stable dosing regimen of adequate
             duration prior to Screening.

        Exclusion Criteria:

          -  Parent or legal guardian is an Alexion employee.

          -  Any active or untreated thymoma. History of thymic carcinoma or thymic malignancy
             unless deemed cured by adequate treatment with no evidence of recurrence for ≥5 years
             before Screening.

          -  History of thymectomy within 12 months prior to Screening.

          -  Are pregnant or lactating.

          -  Any unresolved acute, or chronic, systemic bacterial or other infection, which is
             clinically significant in the opinion of the Investigator and has not been treated
             with appropriate antibiotics.

          -  Use of PE within 4 weeks prior to first dose.

          -  Use of rituximab within 6 months prior to first dose.

          -  Patients who are under 15 kg and are receiving maintenance IVIg.

          -  Participation in another interventional treatment study or use of any experimental
             therapy within 30 days before initiation of study drug on Day 1 in this study or
             within 5 half-lives of that investigational product, whichever is greater.

          -  Have previously received treatment with eculizumab or other complement inhibitors.