Study of ALXN1830 Administered Subcutaneously in Adults With Generalized Myasthenia Gravis

Study Overview
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Brief Summary
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This study will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics (PD), immunogenicity, and efficacy of subcutaneous (SC) ALXN1830 in adults with generalized myasthenia gravis (gMG).

Detailed Description
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Participants have the option to enroll in an Open-label Extension (OLE) Period to receive ALXN1830 up to 58 weeks (including follow-up period).

Official Title
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A Phase 2a Randomized, Double-blind, Placebo-controlled, Parallel Groups, Multicenter Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of ALXN1830 Administered Subcutaneously in Adult Patients With Generalized Myasthenia Gravis

Conditions
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Generalized Myasthenia Gravis

Intervention / Treatment
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* Drug: ALXN1830
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Diagnosis of myasthenia gravis. Positive serologic test for anti-acetylcholine receptor antibodies. Myasthenia Gravis Foundation of America Clinical Classification Class II to IV at Screening. MG-ADL profile must be ≥ 5. Participants receiving stable treatment with azathioprine; other immunosuppressive therapies. Total IgG level at Screening ≥ 600 milligrams/deciliter. Key Exclusion Criteria: History of thymectomy, thymomectomy, or any other thymic surgery within 12 months prior to Screening. Any untreated thymic malignancy, carcinoma, or thymoma. Intravenous immunoglobulin within the 6 weeks, and/or use of plasmapheresis/plasma exchange prior to randomization (Day 1). Use of rituximab within the 3 months (90 days) prior to Screening. Participants who have received previous treatment with any biological agent or other anti-neonatal fragment crystallizable receptor therapy within 5 half-lives or 90 days after last dose (whichever is longer). Known medical or psychological condition(s) or risk factor that, in the opinion of the Investigator, might interfere with the participant's full participation in the study, pose any additional risk for the participant, or confound the assessment of the participant or outcome of the study.

Ages Eligible for Study
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Minimum Age: 18 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: ALXN1830 Dosing Arm 1<br>Participants will receive ALXN1830. Treatment will be received for 16 weeks followed by an Observation Period (no treatment) for 8 weeks. | Drug: ALXN1830<br>* Administered as an SC infusion.<br>|
| Experimental: ALXN1830 Dosing Arm 2<br>Participants will receive ALXN1830. Treatment will be received for 16 weeks followed by an Observation Period (no treatment) for 8 weeks. | Drug: ALXN1830<br>* Administered as an SC infusion.<br>|
| Experimental: ALXN1830 Dosing Arm 3<br>Participants will receive placebo for 8 weeks, then ALXN1830 for 8 weeks, followed by an Observation Period (no treatment) for 8 weeks. | Drug: ALXN1830<br>* Administered as an SC infusion.<br>Other: Placebo<br>* Administered as an SC infusion.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adverse Events (AEs) And Serious Adverse Events (SAEs) Up To Week 24 |  | Up to Week 24 | 
| AEs And SAEs Up To Week 82 |  | Up to Week 82 (OLE) | 
| Change From Baseline In Serum Total Immunoglobulin G (IgG) |  | Up to Week 24 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline In Myasthenia Gravis Activities Of Daily Living Profile (MG-ADL) Total Score |  | Up to Week 24 | 
| Change From Baseline In Quantitative Myasthenia Gravis (QMG) Score |  | Up to Week 24 | 
| Number Of Participants With At Least A 2-point Improvement In The MG-ADL Score Over 4 Consecutive Weeks |  | Up to Week 24 | 
| Number Of Participants With At Least A 3-point Improvement In The QMG Score Over 4 Consecutive Weeks |  | Up to Week 8 | 
| Change From Baseline In Neurological Disorders Fatigue Questionnaire (Neuro-Qol) Fatigue Score |  | Up to Week 24 | 
| Serum Trough Concentrations Of ALXN1830 |  | Up to Week 24 | 
| Change From Baseline In IgG Subtypes |  | Up to Week 24 | 
| Incidence Of Anti-drug Antibodies (ADA) And Neutralizing Antibodies (Nab) Against ALXN1830 |  | Up to Week 24 | 
| Titers Of ADA And Nab Against ALXN1830 |  | Up to Week 24 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Generalized Myasthenia Gravis