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.

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.

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

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.

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.

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.