Efficacy, Safety, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Eculizumab in Chinese Adults With gMG (ECU-MG-304)

An Open-label, Single-arm, Multi-center Study to Evaluate the Efficacy, Safety, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Eculizumab in Chinese Participants With Refractory Generalized Myasthenia Gravis (gMG)

This is an open-label, single-arm, multi-center study to evaluate the efficacy, safety, PK, PD, and immunogenicity of eculizumab in Chinese participants with refractory gMG. Approximately 15 participants will be enrolled in the study.

Study Overview

• Status: Completed
• Conditions: Generalized Myasthenia Gravis (gMG); Refractory gMG
• Intervention / Treatment: Drug: Eculizumab

Detailed Description

This post-approval study is an open-label, single-arm, multi-center study to evaluate the efficacy, safety, PK, PD, and immunogenicity of eculizumab in Chinese participants with refractory gMG. There will be 3 periods in this study: Screening Period (up to 4 weeks), Treatment Period (26 weeks, including an Induction Phase and a Maintenance Phase), and Safety Follow-up Period (8 weeks). The overall study duration for an individual participant is estimated to be up to 38 weeks. Approximately 15 participants will be enrolled in the study.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Phase 3

Contacts and Locations

Study Locations

• China
  • Changchun, China, 130021
    • Research Site
  • Fuzhou, China, 350001
    • Research Site
  • Guangzhou, China, 510620
    • Research Site
  • Guangzhou, China, 510080
    • Research Site
  • Qingdao, China, 266035
    • Research Site
  • Shanghai, China, 200040
    • Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of MG must be made by the following tests:

  1. Positive serologic test for anti-AChR Abs as confirmed at Screening, and

  2. One of the following:

     1. Abnormal neuromuscular transmission demonstrated by repetitive nerve stimulation, or
     2. History of positive anticholinesterase test, eg, neostigmine test, or
     3. Participant has demonstrated improvement in MG signs on oral cholinesterase inhibitors as assessed by the treating physician
• MGFA Clinical Classification Class II to IV at Screening
• MG-ADL total score must be ≥ 6 at Screening and Day 1

• Participants who have:

  1. Failed treatment with 2 or more ISTs over one year (either in combination or as monotherapy), ie, continue to have impairment ADLs (persistent weakness, experience crisis, or unable to tolerate IST) despite ISTs or,
  2. Failed at least one IST and require chronic PE or IVIg to control symptoms, ie, participants who require PE or IVIg on a regular basis for the management of muscle weakness at least 2 cycles over last 12 months

Exclusion Criteria:

• Any untreated thymic malignancy, carcinoma, or thymoma

• History of thymectomy or any other thymic surgery within 6 months prior to Screening. Participants with a history of treated thymic malignancy or carcinoma are eligible if they meet all of the following conditions:

  1. Treatment completed > 5 years prior to the Screening Visit
  2. No recurrence within the 5 years prior to the Screening Visit
  3. No radiological indication of recurrence in a computed tomography (CT) or magnetic resonance imaging (MRI) scan, including administration of intravenous (IV) contrast, performed within 6 months of first dose on Day 1
• Weakness only affecting ocular or peri-ocular muscles (MGFA Class I)
• MG crisis at Screening (MGFA Class V). However, such participants may be rescreened with Alexion approval once they are treated and medically stable, in the opinion of the Investigator
• History of N meningitidis infection or unresolved meningococcal disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Eculizumab	Drug: Eculizumab; Participants will receive Eculizumab via intravenous (IV) infusion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To assess the efficacy of eculizumab in the treatment of refractory gMG based on the improvement in the MG-ADL	The mean change of Myasthenia Gravis Activities of Daily Living Profile (MG-ADL) total score from baseline at Week 26 along with 2-sided 95% CI	from baseline at Week 26

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To assess the efficacy of eculizumab in the treatment of refractory gMG by QMG	The mean change of quantitative myasthenia gravis (QMG) total score from baseline at Week 26 along with 2-sided 95% CI	from baseline at Week 26
To assess the efficacy of eculizumab in the treatment of refractory gMG by MGC	The mean change of myasthenia gravis composite (MGC) total score from baseline at Week 26 along with 2-sided 95% CI	from baseline at Week 26
To assess the efficacy of eculizumab in the treatment of refractory gMG by MG-QoL 15r	The mean change of revised Myasthenia Gravis Quality of Life 15-Item Scale (MG-QoL 15r scale) from baseline at Week 26 along with 2-sided 95% CI	from baseline at Week 26
To assess the efficacy of eculizumab in the treatment of refractory gMG by MG-ADL responder status	The proportion of participants who achieve the Myasthenia Gravis Activities of Daily Living Profile (MG-ADL) response at Week 26, along with the 2-sided 95% CI	from baseline at Week 26
To assess the efficacy of eculizumab in the treatment of refractory gMG by QMG responder analysis	The proportion of participants who achieve the quantitative myasthenia gravis (QMG) response at Week 26, along with the 2-sided 95% CI	from baseline at Week 26
To assess the safety and tolerability of eculizumab in the treatment of refractory gMG	Incidence of AEs, SAEs, and AEs leading to study intervention discontinuation (onset after first infusion)	from baseline at Week 26
To characterize the PK of eculizumab in participants with refractory gMG	Mean serum eculizumab concentrations at all scheduled visits	from baseline at Week 26
To characterize the PD of eculizumab in participants with refractory gMG	Mean changes in serum free complement component 5 (C5) concentrations at all scheduled visits	from baseline at Week 26
To characterize the immunogenicity of eculizumab in participants with refractory gMG	Proportion of treatment-emergent anti-drug antibody (ADA) positive participants	from baseline at Week 26

Collaborators and Investigators

• Sponsor: Alexion Pharmaceuticals, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): January 6, 2025
• Primary Completion (Actual): December 29, 2025
• Study Completion (Actual): December 29, 2025

Study Registration Dates

• First Submitted: December 11, 2024
• First Submitted That Met QC Criteria: January 2, 2025
• First Posted (Actual): January 8, 2025

Study Record Updates

• Last Update Posted (Actual): January 15, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Eculizumab; Generalized Myasthenia Gravis (gMG); Refractory gMG
• Additional Relevant MeSH Terms: Nervous System Diseases; Neoplasms by Site; Neoplasms; Neuromuscular Diseases; Autoimmune Diseases; Immune System Diseases; Autoimmune Diseases of the Nervous System; Neurodegenerative Diseases; Paraneoplastic Syndromes, Nervous System; Nervous System Neoplasms; Paraneoplastic Syndromes; Neuromuscular Junction Diseases; Myasthenia Gravis; Immunosuppressive Agents; Immunologic Factors; Physiological Effects of Drugs; Complement Inactivating Agents; eculizumab
• Other Study ID Numbers: D7411C00003; ECU-MG-304 (Other Identifier: Alexion)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal.

All request will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

• IPD Sharing Time Frame: AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please refer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.
• IPD Sharing Access Criteria: When a request has been approved AstraZeneca will provide access to the deidentified individual patient-level data in an approved sponsored tool. Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No