PK, PD, Safety, and Efficacy Study of Gefurulimab in Pediatric Patients With AChR+ Generalized Myasthenia Gravis

March 31, 2026 updated by: Alexion Pharmaceuticals, Inc.

An Open-Label, Single-arm Study to Evaluate the Pharmacokinetics (PK), Pharmacodynamics (PD), Safety, and Efficacy of Gefurulimab in Pediatric Patients (6 to < 18 Years of Age) With Generalized Myasthenia Gravis (gMG) Who Express Acetylcholine Receptor Antibodies (AChR+)

The primary objective of this study is to assess the pharmacokinetics and pharmacodynamics of gefurulimab in pediatric participants with AChR+ gMG for the duration of the study.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

12

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Brazil
      • Joinville, Brazil, 89202-451
        • Recruiting
        • Research Site
      • Salvador, Brazil, 41253-190
        • Recruiting
        • Research Site
      • São José do Rio Preto, Brazil, 15090-000
        • Recruiting
        • Research Site
      • São Paulo, Brazil, 05403-000
        • Recruiting
        • Research Site
      • São Paulo, Brazil, 0438-002
        • Recruiting
        • Research Site
  • Japan
      • Saitama-Shi, Japan, 330-8777
        • Recruiting
        • Research Site
  • Poland
      • Bydgoszcz, Poland, 85-065
        • Withdrawn
        • Research Site
      • Lodz, Poland, 93-338
        • Withdrawn
        • Research Site
      • Warsaw, Poland, 02-097
        • Recruiting
        • Research Site
  • Taiwan
      • New Taipei City, Taiwan, 23561
        • Recruiting
        • Research Site
      • Taipei, Taiwan, 11101
        • Recruiting
        • Research Site
  • United States
    • District of Columbia
      • Washington D.C., District of Columbia, United States, 20010
        • Recruiting
        • Research Site
    • Virginia
      • Norfolk, Virginia, United States, 23507
        • Recruiting
        • Research Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

United States of America (USA) specific inclusion criterion:

  • Participant must be 12 to < 18 years of age at the time of signing the informed consent/assent.
  • All participants must be vaccinated against meningococcal infection from serogroups A, B, C, W, and Y within 3 years and at least 2 weeks prior to the first dose of study intervention administration.

Rest of World (ROW) specific inclusion criteria:

  • Participant must be 6 to < 18 years of age at the time of signing the informed consent/assent.
  • All participants must be vaccinated against meningococcal infection from serogroups A, C, W, Y (and B where available) within 3 years prior to study intervention on Day 1. If vaccination occurs < 2 weeks prior to Day 1, the participants will receive prophylactic antibiotics for at least 2 weeks after initial meningococcal vaccination for serogroups A,C,W,Y (and B, where available)

Global 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Gefurulimab
On Day 1, participants will receive a weight based loading dose followed by a weekly maintenance dose for up to 122 weeks.
Combination product: Gefurulimab
Combination product consisting of syringe prefilled with gefurulimab will be administered weekly via subcutaneous (SC) injection.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Maximum Observed Serum Concentration (Cmax) of Gefurulimab
Time Frame: Day 1 predose through Week 18 predose
Day 1 predose through Week 18 predose
Serum Free Complement Component 5 (C5) Concentration
Time Frame: Day 1 predose through Week 18 predose
Day 1 predose through Week 18 predose

Secondary Outcome Measures

Outcome Measure
Time Frame
Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Treatment-emergent Serious Adverse Events (TESAEs)
Time Frame: Day 1 through Week 134
Day 1 through Week 134
Change in Quantitative Myasthenia Gravis Score for Disease Severity (QMG) Total Score From Baseline Through Week 18
Time Frame: Baseline through Week 18
Baseline through Week 18
Number of Participants With ≥ 5-point Reduction From Baseline in the QMG Total Score Through Week 18
Time Frame: Baseline through Week 18
Baseline through Week 18
Change in Myasthenia Gravis Activities of Daily Living Profile (MG-ADL) Total Score From Baseline Through Week 18
Time Frame: Baseline through Week 18
Baseline through Week 18
Number of Participants With ≥ 3-point Reduction From Baseline in the MG-ADL Total Score Through Week 18
Time Frame: Baseline through Week 18
Baseline through Week 18
Number of Participants With Anti-drug Antibodies (ADAs)
Time Frame: Baseline through Week 134
Baseline through Week 134
Number of ADA Positive Participants With Pre-existing Immunoreactivity,Treatment-emergent or Treatment-boosted ADA Responses
Time Frame: Baseline through Week 134
Baseline through Week 134
Number of ADA Positive Participants With Neutralizing Antibody (NAb) Positive or Negative Status
Time Frame: Baseline through Week 134
Baseline through Week 134

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Alexion Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 13, 2024

Primary Completion (Estimated)

December 15, 2026

Study Completion (Estimated)

January 23, 2029

Study Registration Dates

First Submitted

September 19, 2024

First Submitted That Met QC Criteria

September 19, 2024

First Posted (Actual)

September 23, 2024

Study Record Updates

Last Update Posted (Actual)

April 1, 2026

Last Update Submitted That Met QC Criteria

March 31, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • D6780C00004
  • 2024-515157-17-00 (Other Identifier: EUCT)
  • ALXN1720-MG-302 (Other Identifier: Alexion)
  • U1111-1327-6615 (Other Identifier: WHO)

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.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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