A Phase 3 Study to Evaluate the Efficacy and Safety of Efgartigimod IV in Patients With Acetylcholine Receptor Binding Antibody Seronegative Generalized Myasthenia Gravis

Phase 3

Recruiting

• Conditions: Generalized Myasthenia Gravis
• Interventions: Biological: Efgartigimod IV; Other: Placebo IV

• Registration Number: NCT06298552
• Lead Sponsor: argenx

Brief Summary

The primary purpose of this study is to measure the efficacy and safety of efgartigimod intravenously (IV) compared to placebo in participants with Acetylcholine Receptor Binding Antibody (AChR-Ab) seronegative Generalized Myasthenia Gravis (gMG). Other objectives are to assess long-term efficacy, safety, and tolerability of efgartigimod.

Study will consist of:

* Screening

* Part A: participants will be randomized to receive either efgartigimod IV or placebo

* Part B: participants completing part A will receive open-label efgartigimod IV

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-03-01
• Study First Submitted QC: 2024-03-01
• Study First Posted: 2024-03-07
• Study Start: 2024-04-16
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-02
• Last Update Posted: 2025-05-04
• Primary Completion: 2025-07-25
• Study Completion: 2027-07-23

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 110

Inclusion Criteria

• The participant is at least the local legal age of consent for clinical studies when signing the ICF.

• The participant is capable of providing signed informed consent and following with protocol requirements.

• The participant agrees to use contraceptive measures consistent with local regulations and the women of child-bearing potential (WOCBP) must have a negative serum pregnancy test result at screening and a negative urine pregnancy test result at baseline before receiving the study drug.

• The participant has no known weakness in infancy and later develop fatigable weakness after aged 16 years and diagnosed with acquired gMG of both of the following:

  1. History of abnormal neuromuscular transmission demonstrated by single fiber electromyography or repetitive nerve stimulation (RNS) or is anti-muscle-specific kinase antibodies (MuSK-Ab) seropositive
  2. Either a history of positive edrophonium chloride test OR a demonstrated improvement in MG signs with treatments such as oral acetylcholinesterase (AChE) inhibitors, plasma exchange (PLEX), immunoabsorption, or intravenous immunoglobulin (IVIg)/ subcutaneous immunoglobulin (SCIg) treatment

Exclusion Criteria

• Known autoimmune disease or any medical condition that would interfere with an accurate assessment of clinical symptoms of gMG or puts the participant at undue risk
• History of malignancy, cancer, unless considered cured by adequate treatment with no evidence of recurrence for ≥3 years. Adequately treated participants with the following cancers can be included at any time: Basal cell or squamous cell skin cancer, Carcinoma in situ of the cervix, Carcinoma in situ of the breast, Incidental histological findings of prostate cancer
• Clinically significant active infection that is not sufficiently resolved in the investigator's opinion or positive serum test at screening for active infection with any of the following: Hepatitis B virus (HBV), Hepatitis C virus (HCV), HIV
• Current participation in another interventional clinical study or previous participation in an efgartigimod clinical study and received at least 1 dose of the study drug
• Known hypersensitivity to study drug or one of its excipients (inactive ingredients)
• History of or current alcohol, drug, or medication abuse as assessed by the investigator
• Pregnant or lactating state or intention to become pregnant during the study
• Live or live-attenuated vaccine received <4 weeks before screening
• Worsening muscle weakness secondary to concurrent infections or medications
• Received a thymectomy less than 3 months before screening or thymectomy is planned during the study
• Use of some medications before screening (more information is found in the protocol).

The complete list of exclusion criteria can be found in the protocol.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo IV	Patients receiving placebo during part A and receiving efgartigimod IV during part B
Efgartigimod IV	Efgartigimod IV	Patients receiving efgartigimod IV in both part A and part B
Placebo	Efgartigimod IV	Patients receiving placebo during part A and receiving efgartigimod IV during part B

Primary Outcome Measures

Name	Time	Method
Myasthenia Gravis Activities of Daily Living (MG-ADL) total score change from baseline	Up to 29 days during part A	Minimum value: 0 (normal symptoms); Maximum value: 24 (most severe symptoms)

Secondary Outcome Measures

Name	Time	Method
Quantitative myasthenia gravis (QMG) total score change from baseline	Up to 29 days during part A	Minimum value: 0 (no disease severity); Maximum value: 39 (highest disease severity)
Proportion of participants who are both MG-ADL and QMG responders	Up to 8 weeks during part A

Trial Locations

Locations (91)

Fakultni nemocnice Brno; 🇨🇿 Brno, Czech Republic

HonorHealth Neurology - Bob Bove Neuroscience Institute; 🇺🇸 Scottsdale, Arizona, United States

Loma Linda University Health; 🇺🇸 Fresno, California, United States

First Choice Neurology Boca Raton; 🇺🇸 Boca Raton, Florida, United States

SFM Clinical Research LLC; 🇺🇸 Boca Raton, Florida, United States

The Neurology Institute / Healthcare Innovations Institute - Coral Springs; 🇺🇸 Coral Springs, Florida, United States

Neurology Associates PA; 🇺🇸 Maitland, Florida, United States

Desai Sethi Medical Center; 🇺🇸 Miami, Florida, United States

Medsol Clinical Research Center Inc; 🇺🇸 Port Charlotte, Florida, United States

BayCare - St. Anthony's Hospital; 🇺🇸 Saint Petersburg, Florida, United States

University of South Florida (USF) Health - Morsani Center for Advanced Healthcare; 🇺🇸 Tampa, Florida, United States

Wellstar - Augusta University Medical Center; 🇺🇸 Augusta, Georgia, United States

Kansas University Medical Center - Kansas City; 🇺🇸 Fairway, Kansas, United States

Rutgers-Robert Wood Johnson Medical School; 🇺🇸 New Brunswick, New Jersey, United States

University of North Carolina - Chapel Hill; 🇺🇸 Chapel Hill, North Carolina, United States

Duke University School of Medicine - Duke Early Phase Clinical Research Unit; 🇺🇸 Durham, North Carolina, United States

Cleveland Clinic; 🇺🇸 Cleveland, Ohio, United States

Erlanger Neuroscience Institute; 🇺🇸 Chattanooga, Tennessee, United States

National Neuromuscular Research Institute; 🇺🇸 Austin, Texas, United States

University of Washington Medical Center - Montlake; 🇺🇸 Seattle, Washington, United States

Hôpital Erasme; 🇧🇪 Anderlecht, Belgium

Cliniques Universitaires Saint-Luc; 🇧🇪 Brussels, Belgium

AZ Sint-Lucas Gent; 🇧🇪 Gent, Belgium

UZ Leuven; 🇧🇪 Leuven, Belgium

Heritage Medical Research Clinic; 🇨🇦 Calgary, Canada

Genge Partners Inc.; 🇨🇦 Montreal, Canada

Ottawa Hospital - Civic Campus; 🇨🇦 Ottawa, Canada

Xuanwu Hospital Capital Medical University; 🇨🇳 Beijing, China

The First Hospital of Jilin University; 🇨🇳 Changchun, China

Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital; 🇨🇳 Chongqing, China

The First Affiliated Hospital of Chongqing Medical University; 🇨🇳 Chongqing, China

Fujian Medical University Union Hospital; 🇨🇳 Fuzhou, China

The First Affiliated Hospital of Guangxi Medical University; 🇨🇳 Guangxi, China

The First Affiliated Hospital of Guangzhou University Chinese Medicine; 🇨🇳 Guangzhou, China

Guangdong Province Traditional Chinese Medical Hospital; 🇨🇳 Guangzhou, China

The Affiliated Hospital of Guizhou Medical University; 🇨🇳 Guiyang, China

Ningbo Medical Center Lihuili Hospital; 🇨🇳 Ningbo, China

Qilu Hospital of Shandong University; 🇨🇳 Qingdao, China

Huashan Hospital Fudan University; 🇨🇳 Shanghai, China

First Hospital of Shanxi Medical University; 🇨🇳 Taiyuan, China

Tongji Hospital Tongji Medical College Huazhong University of Science and Technology; 🇨🇳 Wuhan, China

Cyprus Institute of Neurology and Genetics; 🇨🇾 Egkomi, Cyprus

Nemocnice Pardubickeho kraje, a.s., Pardubicka nemocnice; 🇨🇿 Pardubice, Czech Republic

Aarhus Universitetshospital; 🇩🇰 Aarhus, Denmark

Rigshospitalet; 🇩🇰 Copenhagen, Denmark

Odense Universitetshospital; 🇩🇰 Odense C, Denmark

Turun Yliopistollinen Keskussairaala; 🇫🇮 Turku, Finland

AP-HM- Hôpital de La Timone; 🇫🇷 Marseille, France

CHU de Nice-Hôpital Pasteur; 🇫🇷 Nice, France

AP-HP - Hôpital de la Pitié Salpétrière; 🇫🇷 Paris, France

West Georgia Medical Center; 🇬🇪 Kutaisi, Georgia

Petre Sarajishvili Institute of Neurology; 🇬🇪 Tbilisi, Georgia

Pineo Medical Ecosystem; 🇬🇪 Tbilisi, Georgia

New Hospitals; 🇬🇪 Tbilisi, Georgia

LLC Caucasus Medical Centre; 🇬🇪 Tbilisi, Georgia

Charité - Universitätsmedizin Berlin; 🇩🇪 Berlin, Germany

Katholisches Klinikum Bochum - St. Josef Hospital; 🇩🇪 Bochum, Germany

Universitätsklinikum Würzburg; 🇩🇪 Würzburg, Germany

Eginitio Hospital; 🇬🇷 Athens, Greece

University General Hospital ''ATTIKON''; 🇬🇷 Chaidari, Greece

University General Hospital of Patras; 🇬🇷 Patra, Greece

AHEPA University General Hospital of Thessaloniki; 🇬🇷 Thessaloniki, Greece

Semmelweis Egyetem Genomikai Medicina és Ritka Betegségek Intézete; 🇭🇺 Budapest, Hungary

Leiden University Medical Center; 🇳🇱 Leiden, Netherlands

Universitair Medisch Centrum Utrecht; 🇳🇱 Utrecht, Netherlands

Haukeland Universitetssykehus; 🇳🇴 Bergen, Norway

Oslo Universitetssykehus HF, Ullevål; 🇳🇴 Oslo, Norway

MICS Centrum Medyczne Bydgoszcz; 🇵🇱 Bydgoszcz, Poland

Centrum Medyczne Neurologia Slaska; 🇵🇱 Katowice, Poland

Szpital Uniwersytecki w Krakowie; 🇵🇱 Kraków, Poland

Krakowska Akademia Neurologii Sp. z o.o.; 🇵🇱 Kraków, Poland

CLINIREM Sp z o.o.; 🇵🇱 Lublin, Poland

Uniwersytecki Szpital Kliniczny im. Jana Mikulicza Radeckiego we Wroclawiu; 🇵🇱 Wrocław, Poland

ULS de Santa Maria, EPE - Hospital de Santa Maria; 🇵🇹 Lisboa, Portugal

ULS de Lisboa Ocidental, EPE - Hospital Egas Moniz; 🇵🇹 Lisboa, Portugal

Hospital de Santo António - Unidade Local de Saúde de Santo António; 🇵🇹 Porto, Portugal

Cluj County Emergency Clinical Hospital; 🇷🇴 Cluj Napoca, Romania

Sibiu Emergency County Clinical Hospital; 🇷🇴 Sibiu, Romania

King Faisal Specialist Hospital & Research Center; 🇸🇦 Riyadh, Saudi Arabia

National Guard Riyadh; 🇸🇦 Riyadh, Saudi Arabia

Opsta bolnica MSB - Medicinski Sistemi Beograd; 🇷🇸 Belgrade, Serbia

University Clinical Center Kragujevac; 🇷🇸 Kragujevac, Serbia

Hospital General Universitario Dr. Balmis; 🇪🇸 Alicante, Spain

Hospital Universitario Vall d'Hebron - PPDS; 🇪🇸 Barcelona, Spain

Hospital de La Santa Creu i Sant Pau; 🇪🇸 Barcelona, Spain

Hospital Universitari Arnau de Vilanova; 🇪🇸 Lleida, Spain

Hospital Universitario Ramon y Cajal; 🇪🇸 Madrid, Spain

Hospital Clinico Universitario de Santiago; 🇪🇸 Santiago de Compostela, Spain

Hospital Universitari i Politecnic La Fe de Valencia; 🇪🇸 Valencia, Spain

Panthera Biopartners; 🇬🇧 Glasgow, United Kingdom

Leeds General Infirmary; 🇬🇧 Leeds, United Kingdom