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

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 13, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 15, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 23, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 19, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 19, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 23, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 31, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings