Gefurulimab for Myasthenia Gravis

Recruiting at 15 trial locations

Overseen By Alexion Pharmaceuticals, Inc. (Sponsor)

Age: < 18

Sex: Any

Trial Phase: Phase 3

Sponsor: Alexion Pharmaceuticals, Inc.

Disqualifiers: Thymectomy, Thymic malignancy, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: Unknown

Duration: 122 weeks

12 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests an experimental treatment called gefurulimab for children and teens with myasthenia gravis, a condition that causes muscle weakness. The goal is to understand how the body processes and reacts to this treatment. Participants will initially receive a dose based on their weight, followed by a weekly dose for up to 122 weeks. This trial suits children aged 6-18 diagnosed with myasthenia gravis who test positive for specific antibodies related to the condition. Participants must also be vaccinated against certain infections before joining. As a Phase 3 trial, this study represents the final step before FDA approval, offering participants a chance to contribute to a potentially groundbreaking treatment.

Do I need to stop my current medications for the trial?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

Is there any evidence suggesting that gefurulimab is likely to be safe for humans?

Research has shown that gefurulimab is generally safe for people with myasthenia gravis. In earlier studies, patients experienced significant symptom relief and managed daily activities better without serious side effects over 26 weeks. Although these studies focused on adults, the results are promising for the treatment's safety in humans. This trial is in Phase 3, indicating substantial evidence from earlier trials supporting its safety. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for myasthenia gravis?

Gefurulimab is unique because it offers a new approach to treating myasthenia gravis by potentially targeting specific immune pathways involved in the condition. Most current treatments, like corticosteroids and immunosuppressants, broadly suppress the immune system, which can lead to significant side effects. Gefurulimab, on the other hand, is being developed to more selectively modulate immune activity, aiming to reduce symptoms with potentially fewer side effects. Researchers are excited about this treatment because of its promise to improve patient quality of life by offering a more targeted and possibly safer therapy option.

What evidence suggests that gefurulimab might be an effective treatment for myasthenia gravis?

Research shows that gefurulimab, the investigational treatment in this trial, may effectively treat generalized myasthenia gravis (gMG). Studies found it led to noticeable improvements in daily activities affected by the disease, as measured by the Myasthenia Gravis Activities of Daily Living (MG-ADL) score. These improvements appeared as early as the first week and continued through week 26. The treatment also improved scores on the Quantitative Myasthenia Gravis (QMG) scale, which measures disease severity. Gefurulimab blocks a part of the immune system called the complement pathway, which contributes to gMG symptoms. Overall, evidence suggests gefurulimab could effectively manage gMG symptoms. ^{1 2 3 4 5}

Are You a Good Fit for This Trial?

This trial is for pediatric patients aged 6 to less than 18 with generalized muscle weakness due to AChR+ Myasthenia Gravis. They must have tested positive for specific autoantibodies and be vaccinated against certain meningococcal infections, or take antibiotics if recently vaccinated. Those with untreated thymic conditions, recent thymic surgery, a history of certain infections, or who are pregnant cannot participate.

Inclusion Criteria

Positive serological test for autoantibodies against AChR

I am between 6 and 17 years old.

I have been diagnosed with Myasthenia Gravis and experience moderate to severe muscle weakness.

Exclusion Criteria

I have an untreated cancer of the thymus.

I have not had thymus gland surgery in the last year.

History of Neisseria meningitidis infection

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive a weight-based loading dose of gefurulimab followed by a weekly maintenance dose

122 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

4-8 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Gefurulimab

Trial Overview The study aims to evaluate the effects and body's handling (pharmacokinetics/pharmacodynamics) of Gefurulimab in children with AChR+ generalized Myasthenia Gravis over the course of the study.

How Is the Trial Designed?

Group I: Gefurulimab Experimental Treatment 1 Intervention

On Day 1, participants will receive a weight based loading dose followed by a weekly maintenance dose for up to 122 weeks.

Who Is Running the Clinical Trial?

Alexion Pharmaceuticals, Inc.

Lead Sponsor

Trials

267

Recruited

141,000+

Dr. Alberto R. Martinez

Alexion Pharmaceuticals, Inc.

Chief Medical Officer since 2010

MD from University of Sao Paulo

Marc Dunoyer

Alexion Pharmaceuticals, Inc.

Chief Executive Officer since 2021

PhD in Molecular Biology

Published Research Related to This Trial

A new sum score has been developed to define treatment-refractory generalized myasthenia gravis (TRgMG), which includes criteria such as disease severity and inefficacy of previous therapies, making it easier for clinicians to make treatment decisions.

This scoring system, created through a consensus of 12 experts and based on a thorough literature review, aims to clarify when eculizumab should be used and can also serve as a basis for inclusion criteria in future clinical studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Sum Score to Define Therapy-Refractory Myasthenia Gravis: A German Consensus. Schroeter, M., Berger, B., Blaes, F., et al.[2022]

In a subgroup of patients with treatment-refractory generalized myasthenia gravis who had previously received chronic intravenous immunoglobulin (IVIg), eculizumab demonstrated sustained clinical improvements over 18 months compared to placebo.

Eculizumab was associated with a lower rate of disease exacerbations and was well tolerated, indicating its efficacy and safety for patients transitioning from IVIg treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Response to eculizumab in patients with myasthenia gravis recently treated with chronic IVIg: a subgroup analysis of REGAIN and its open-label extension study. Jacob, S., Murai, H., Utsugisawa, K., et al.[2022]

Eculizumab significantly improved outcomes in patients with anti-acetylcholine receptor-positive refractory generalized myasthenia gravis (gMG), with 25.0% achieving minimal manifestations (MM) after 26 weeks compared to 13.3% in the placebo group.

After 130 weeks of treatment, 88.0% of patients on eculizumab reported improved status, and 57.3% achieved MM, demonstrating both rapid and sustained efficacy without new safety concerns.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension. Mantegazza, R., Wolfe, GI., Muppidi, S., et al.[2021]

In a study of 25 patients with anti-muscle-specific kinase (MuSK) myasthenia gravis, the rituximab protocol 4 + 2 resulted in significantly fewer relapses (18.2%) and a longer time to relapse (mean 3.5 years) compared to other protocols.

The protocol 1 + 1 had a much higher relapse rate (80%) and a shorter time to relapse (mean 1.1 years), indicating that the choice of rituximab protocol can greatly affect treatment outcomes in MuSK MG.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The impact of rituximab infusion protocol on the long-term outcome in anti-MuSK myasthenia gravis. Cortés-Vicente, E., Rojas-Garcia, R., Díaz-Manera, J., et al.[2022]

Eculizumab, a terminal complement inhibitor, significantly improves muscle strength and daily activities in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis, as shown in a study with 125 participants.

Improvements in muscle strength and daily living activities were rapid and sustained over 130 weeks, indicating the long-term efficacy of eculizumab in managing this condition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consistent improvement with eculizumab across muscle groups in myasthenia gravis. Mantegazza, R., O'Brien, FL., Yountz, M., et al.[2023]

Citations

1. astrazeneca-us.com astrazeneca-us.com/media/press-releases/2025/Gefurulimab-demonstrates-statistically-significant-and-clinically-meaningful-improvement-in-Myasthenia-Gravis-Activities-of-Daily-Living-MG-ADL-at-week-26-with-clinically-meaningful-improvement-seen-as-early-as-week-one-in-adults-with-gMG-in-PREVAIL-Phase-III-trial.html

Gefurulimab demonstrates statistically significant and ... Trial met all secondary endpoints including change from baseline in quantitative myasthenia gravis total score at week four and week 26.

2. astrazeneca.com astrazeneca.com/media-centre/press-releases/2025/alexion-data-presented-at-2025-aanem-annual-meeting-and-mgfa-scientific-session-underscores-pioneering-c5-inhibition-leadership-in-gmg.html

Alexion data presented at 2025 AANEM Annual Meeting ... The trial met its primary and all secondary endpoints, with gefurulimab demonstrating a statistically significant and clinically meaningful ...

3. clinicaltrials.gov clinicaltrials.gov/study/NCT05556096

NCT05556096 | Safety and Efficacy of ALXN1720 in Adults ... 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 ...

4. ajmc.com ajmc.com/view/gefurulimab-for-mg-exhibits-lasting-efficacy-safety-in-topline-prevail-trial-data

Gefurulimab for MG Exhibits Lasting Efficacy, Safety in ... Gefurulimab showed significant improvements in MG-ADL and QMG scores in the phase 3 PREVAIL trial, with early benefits sustained through week 26 ...

5. neurology.org neurology.org/doi/10.1212/WNL.0000000000208763

The Phase 3 PREVAIL Study Assessing the Efficacy and ... Gefurulimab is a new investigational complement inhibitor that binds C5, blocks its enzymatic cleavage, and thus, inhibits the terminal complement pathway.