Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the safety and efficacy of ALXN1720 for the treatment of generalized MG (gMG) in adults with autoantibodies against acetylcholine receptor (AChR).

Official Title
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A Phase 3, Randomized, Double-blind, Placebo-controlled, Parallel, Multicenter Study to Evaluate the Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis

Conditions
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Generalized Myasthenia Gravis

Intervention / Treatment
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* Combination Product: ALXN1720
* Combination Product: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of MG with generalized muscle weakness meeting the clinical criteria defined by Myasthenia Gravis Foundation of America (MGFA) Class II, III or IV Positive serological test for autoantibodies against AChR Exclusion Criteria: History of thymectomy, or any other thymic surgery within 12 months prior to Screening Untreated thymic malignancy, carcinoma, or thymoma History of Neisseria meningitidis infection Pregnancy, breastfeeding, or intention to conceive during the course 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
Interventional Model Description: This is a treatment study with 2 parallel intervention groups. The study is blinded for sponsor staff, sponsor designees, investigative site personnel, other staff directly associated with the conduct of the study, and study participants.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ALXN1720<br>Participants will receive a weight-based initial (loading) dose of ALXN1720 on Day 1, followed by weight-based maintenance treatment with ALXN1720 on Day 8 and once every week (Q1W) thereafter for a total of 26 weeks. Following this randomized controlled treatment (RCT) period, all participants will receive ALXN1720 in an open-label extension (OLE) period of 105 weeks. | Combination Product: ALXN1720<br>* Combination product consisting of syringe prefilled with ALXN1720.<br>|
| Placebo Comparator: Placebo<br>Participants will receive placebo during the 26-week RCT period, after which they will enter the OLE period of the study and receive ALXN1720. | Combination Product: Placebo<br>* Combination product consisting of syringe prefilled with placebo.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26 |  | Baseline, Week 26 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Quantitative Myasthenia Gravis (QMG) Total Score at Week 26 |  | Baseline, Week 26 | 
| Percentage of Responders Based on Reduction of the MG-ADL Total Score at Week 26 | Response defined as reduction of the MG-ADL total score by >= 3 points from baseline at Week 26. | Baseline up to Week 26 | 
| Percentage of Responders based on Reduction of the QMG Total Score at Week 26 | Response defined as reduction of the QMG total score by >= 5 points from baseline at Week 26 | Baseline up to Week 26 | 
| Change From Baseline in Myasthenia Gravis Composite (MGC) Total Score at Week 26 |  | Baseline, Week 26 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ALXN1720, anti-acetylcholine receptor antibody-positive, acetylcholine receptor, AChR, generalized myasthenia gravis, myasthenia gravis, MG, gMG, complement component 5, C5, VHH antibody