Generalized Myasthenia GravisPhase 3ADAPT SERONNCT06298552
A Phase 3 Study to Evaluate the Efficacy and Safety of Efgartigimod IV in Patients With Acetylcholine Receptor Binding Antibody Seronegative Generalized Myasthenia Gravis
A Phase 3 study testing Efgartigimod IV in people with Generalized Myasthenia Gravis and gMG, run by argenx at 91 sites in 22 countries.
Trial summary
The primary purpose of this study is to measure the efficacy and safety of efgartigimod IV compared to placebo in participants with Acetylcholine Receptor Binding Antibody (AChR-Ab) seronegative Generalized Myasthenia Gravis (gMG). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Generalized Myasthenia Gravis, gMG, Myasthenia Gravis, Generalized
- What is being tested?
- Efgartigimod IV
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 119 participants
- Where
- 91 sitesin 22 countries
- Study dates
- 16 Apr 2024to Jun 2028
- Phase
- Phase 3
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- The participant is at least 18 years of age and 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:
- History of abnormal neuromuscular transmission demonstrated by single fiber electromyography or repetitive nerve stimulation (RNS) or is for anti-muscle-specific kinase antibodies (MuSK-Ab) seropositive
- 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
- The participant is receiving a stable dose of MG therapy before screening, including acetylcholinesterase (AChE) inhibitors, steroids, or nonsteroidal immunosuppressive therapies (NSISTs) in combination or alone
Who cannot join
- 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
- 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
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- 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
- The complete list of exclusion criteria can be found in the protocol.
Trial locations and contacts
91 sites in 22 countries.
91 sites in 22 countries
United States19 sites
Wellstar - Augusta University Medical Center
Augusta, Georgia, 30912
National Neuromuscular Research Institute
Austin, Texas, 78756
First Choice Neurology Boca Raton
Boca Raton, Florida, 33428
SFM Clinical Research LLC
Boca Raton, Florida, 33487
University of North Carolina - Chapel Hill
Chapel Hill, North Carolina, 27599-7025
Erlanger Neuroscience Institute
Chattanooga, Tennessee, 37403-2173
Cleveland Clinic
Cleveland, Ohio, 44195
The Neurology Institute / Healthcare Innovations Institute - Coral Springs
Coral Springs, Florida, 33067
Duke University School of Medicine - Duke Early Phase Clinical Research Unit
Durham, North Carolina, 27710
Kansas University Medical Center - Kansas City
Fairway, Kansas, 66205
Loma Linda University Health
Fresno, California, 93701-2234
Neurology Associates PA
Maitland, Florida, 32751
Desai Sethi Medical Center
Miami, Florida, 33136
Rutgers-Robert Wood Johnson Medical School
New Brunswick, New Jersey, 08901-1962
Medsol Clinical Research Center Inc
Port Charlotte, Florida, 33952
HonorHealth Neurology - Bob Bove Neuroscience Institute
Scottsdale, Arizona, 85251
University of Washington Medical Center - Montlake
Seattle, Washington, 98195
BayCare - St. Anthony's Hospital
St. Petersburg, Florida, 33705-1410
University of South Florida (USF) Health - Morsani Center for Advanced Healthcare
Tampa, Florida, 33612
China14 sites
Xuanwu Hospital Capital Medical University
Beijing, 100053
The First Hospital of Jilin University
Changchun, 130021
Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital
Chongqing, 400016
The First Affiliated Hospital of Chongqing Medical University
Chongqing, 400016
Fujian Medical University Union Hospital
Fuzhou, 350001
The First Affiliated Hospital of Guangxi Medical University
Guangxi, 530021
The First Affiliated Hospital of Guangzhou University Chinese Medicine
Guangzhou, 510405
Guangdong Province Traditional Chinese Medical Hospital
Guangzhou, 518053
The Affiliated Hospital of Guizhou Medical University
Guiyang, 550004
Ningbo Medical Center Lihuili Hospital
Ningbo, 315041
Qilu Hospital of Shandong University
Qingdao, 266035
Huashan Hospital Fudan University
Shanghai, 200040
First Hospital of Shanxi Medical University
Taiyuan, 030001
Tongji Hospital Tongji Medical College Huazhong University of Science and Technology
Wuhan, 430030
Spain7 sites
Hospital General Universitario Dr. Balmis
Alicante, 03010
Hospital Universitario Vall d'Hebron - PPDS
Barcelona, 8035
Hospital de La Santa Creu i Sant Pau
Barcelona, 8041
Hospital Universitari Arnau de Vilanova
Lleida, 25198
Hospital Universitario Ramon y Cajal
Madrid, 28304
Hospital Clinico Universitario de Santiago
Santiago de Compostela, 15706
Hospital Universitari i Politecnic La Fe de Valencia
Valencia, 46026
Poland6 sites
MICS Centrum Medyczne Bydgoszcz
Bydgoszcz, 85-065
Centrum Medyczne Neurologia Slaska
Katowice, 40-689
Szpital Uniwersytecki w Krakowie
Krakow, 31-503
Krakowska Akademia Neurologii Sp. z o.o.
Krakow, 31-505
CLINIREM Sp z o.o.
Lublin, 20-883
Uniwersytecki Szpital Kliniczny im. Jana Mikulicza Radeckiego we Wroclawiu
Wroclaw, 50-556
Georgia5 sites
West Georgia Medical Center
Kutaisi, 4600
Petre Sarajishvili Institute of Neurology
Tbilisi, 0112
Pineo Medical Ecosystem
Tbilisi, 0112
New Hospitals
Tbilisi, 0114
LLC Caucasus Medical Centre
Tbilisi, 0186
Belgium4 sites
Hôpital Erasme
Anderlecht, 1070
Cliniques Universitaires Saint-Luc
Brussels, 1200
AZ Sint-Lucas Gent
Ghent, 9000
UZ Leuven
Leuven, 3000
Greece4 sites
Eginitio Hospital
Athens, 115 28
University General Hospital ''ATTIKON''
Chaïdári, 124 62
University General Hospital of Patras
Pátrai, 265 04
AHEPA University General Hospital of Thessaloniki
Thessaloniki, 546 36
Canada3 sites
Heritage Medical Research Clinic
Calgary, T2N 4Z6
Genge Partners Inc.
Montreal, H4A 3T2
Ottawa Hospital - Civic Campus
Ottawa, K1H 8L6
Denmark3 sites
Aarhus Universitetshospital
Aarhus, 8200
Rigshospitalet
Copenhagen, 2100
Odense Universitetshospital
Odense C, 5000
France3 sites
AP-HM- Hôpital de La Timone
Marseille, 13386
CHU de Nice-Hôpital Pasteur
Nice, 06000
AP-HP - Hôpital de la Pitié Salpétrière
Paris, 75013
Germany3 sites
Charité - Universitätsmedizin Berlin
Berlin, 13353
Katholisches Klinikum Bochum - St. Josef Hospital
Bochum, 44791
Universitätsklinikum Würzburg
Würzburg, 97080
Portugal3 sites
ULS de Santa Maria, EPE - Hospital de Santa Maria
Lisbon, 1150-199
ULS de Lisboa Ocidental, EPE - Hospital Egas Moniz
Lisbon, 1349-019
Hospital de Santo António - Unidade Local de Saúde de Santo António
Porto, 4050-011
Czechia2 sites
Fakultni nemocnice Brno
Brno, 625 00
Nemocnice Pardubickeho kraje, a.s., Pardubicka nemocnice
Pardubice, 530 03
Netherlands2 sites
Leiden University Medical Center
Leiden, 2333 ZA
Universitair Medisch Centrum Utrecht
Utrecht, 3584 CX
Norway2 sites
Haukeland Universitetssykehus
Bergen, 5021
Oslo Universitetssykehus HF, Ullevål
Oslo, 424
Romania2 sites
Cluj County Emergency Clinical Hospital
Cluj-Napoca, 400012
Sibiu Emergency County Clinical Hospital
Sibiu, 550166
Saudi Arabia2 sites
King Faisal Specialist Hospital & Research Center
Riyadh, 11211
National Guard Riyadh
Riyadh, 14611
Serbia2 sites
Opsta bolnica MSB - Medicinski Sistemi Beograd
Belgrade, 11000
University Clinical Center Kragujevac
Kragujevac, 34000
United Kingdom2 sites
Panthera Biopartners
Glasgow, G51 4TY
Leeds General Infirmary
Leeds, LS1 3EX
Hungary1 site
Semmelweis Egyetem Genomikai Medicina és Ritka Betegségek Intézete
Budapest, 1082
About this study
Official title: A Randomized, Double-Blinded, Placebo-Controlled, Phase 3, Parallel-Group Design Study Evaluating the Efficacy and Safety of Efgartigimod IV in Adult Participants With Acetylcholine Receptor Binding Antibody Seronegative Generalized Myasthenia Gravis
The primary purpose of this study is to measure the efficacy and safety of efgartigimod IV compared to placebo in participants with Acetylcholine Receptor Binding Antibody (AChR-Ab) seronegative Generalized Myasthenia Gravis (gMG). The study consists of a Part A where participants will be randomized to receive either efgartigimod IV or placebo IV and a Part B where participants completing part A will receive open-label efgartigimod IV. Participants will be in the study for up to (approximately) 3.5 years.
- Being tested
- Efgartigimod IV, Placebo IV
- Medical subject headings
- Myasthenia Gravis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Efgartigimod IVBiological
Intravenous infusion of efgartigimod
Placebo IVOther
Intravenous infusion of placebo
| Study group | Role | What they receive |
|---|---|---|
| Efgartigimod IV | Experimental | Patients receiving efgartigimod IV in both part A and part B Receives: Biological: Efgartigimod IV |
| Placebo | Placebo comparator | Patients receiving placebo during part A and receiving efgartigimod IV during part B Receives: Biological: Efgartigimod IV; Other: Placebo IV |
What is being measured
The primary outcome is the main question the study is designed to answer.
MG-ADL Total Score Change From Baseline
The Myasthenia Gravis Activities of Daily Living (MG-ADL) scale is an 8-item instrument used to assess MG symptoms and their effects on daily activities. The total score ranges from 0 (no symptoms) to 24 (most severe symptoms).
Measured: Up to 29 days in part A
Secondary outcomes (10)
QMG Total Score Change From Baseline
The Quantitative Myasthenia Gravis (QMG) score includes 13 items that measure endurance or fatigability and accounts for fluctuations in disease state. The total score ranges from 0 (no symptoms) to 39 (highest disease severity).
Measured: Up to 29 days in part A
Proportion of Participants Who Are Both MG-ADL and QMG Responders in Part A
A participant was an MG-ADL responder if there was a ≥2-point reduction in the MG-ADL total score compared with baseline that was maintained for at least 4 consecutive weeks (ie, at least 5 consecutive visits total), with the first reduction occurring no later than 1 week after the last administration of IMP in part A. A participant was a QMG responder if there was a ≥3-point reduction in the QMG total score compared with baseline that was maintained for at least 4 consecutive weeks (ie, at least 5 consecutive visits total), with the first reduction occurring no later than 1 week after the last administration of IMP in part A.
Measured: Up to 8 weeks (part A)
Proportion of Participants With MSE
Minimal symptom expression (MSE) is defined as an MG-ADL total score of 0 or 1
Measured: Up to 8 weeks (part A) + 3 years (part B)
Proportion of Participants Who Are MG-ADL Responders in Part A
The Myasthenia Gravis Activities of Daily Living (MG- ADL) scale is an 8-item instrument used to assess MG symptoms and their effects on daily activities. The total score ranges from 0 (no symptoms) to 24 (most severe symptoms). A participant was an MG-ADL responder if there was a ≥2-point reduction in the MG-ADL total score compared with baseline that was maintained for at least 4 consecutive weeks (ie, at least 5 consecutive visits total), with the first reduction occurring no later than 1 week after the last administration of IMP in part A.
Measured: Up to 8 weeks (part A)
Proportion of Participants Who Are QMG Responders in Part A
The Quantitative myasthenia gravis (QMG) includes 13 items that measure endurance or fatigability and accounts for fluctuations in disease state. The total score ranges from 0 (no symptoms) to 39 (highest disease severity). A participant was a QMG responder if there was a ≥3-point reduction in the QMG total score compared with baseline that was maintained for at least 4 consecutive weeks (ie, at least 5 consecutive visits total), with the first reduction occurring no later than 1 week after the last administration of IMP in part A.
Measured: Up to 8 weeks (part A)
Proportion of Participants Who Are Early MG-ADL Responders in Part A
The Myasthenia Gravis Activities of Daily Living (MG- ADL) scale is an 8-item instrument used to assess MG symptoms and their effects on daily activities. The total score ranges from 0 (no symptoms) to 24 (most severe symptoms). An Early MG-ADL responder is an MG-ADL responder who had an onset of an MG-ADL response no later than 2 weeks after the first administration of IMP in part A.
Measured: Up to 8 weeks (part A)
MG-ADL Total Score Change From Baseline Over Time in Part A and Part A+B
The Myasthenia Gravis Activities of Daily Living (MG- ADL) scale is an 8-item instrument used to assess MG symptoms and their effects on daily activities. The total score ranges from 0 (no symptoms) to 24 (most severe symptoms).
Measured: Up to 8 weeks (part A) + 3 years (part B)
MG-QoL15r Change From Baseline Over Time in Part A and Part A+B
The Myasthenia Gravis Quality of Life-15 revised (MG-QoL15r) is a patient-reported instrument that measures the impact of MG symptoms on quality of life. The total scores range from 0 (best outcome) to 30 (worst outcome).
Measured: Up to 8 weeks (part A) + 3 years (part B)
EQ-5D-5L VAS Change From Baseline Over Time in Part A and Part A+B
The EQ-5D-5L is a participant-reported measure of health status developed by the EuroQol Group. The questionnaire comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Current health status is rated on vertical visual analog score (VAS) from 0 to 100, with a score of 0 corresponding to "the worst health you can imagine" and 100 corresponding to "the best health you can imagine."
Measured: Up to 8 weeks (part A) + 3 years (part B)
Total IgG Concentrations Percent Changes From Baseline Over Time in Part A and Part A+B
Measured: Up to 8 weeks (part A) + 3 years (part B)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Mar 2024
- Study start16 Apr 2024
- Primary completion30 Jun 2025
- Study completionJun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Generalized Myasthenia GravisStudies of the same condition, open and under way.
- More trials run by argenxThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 119 participants (actual)
Sponsor and investigators
- Lead sponsor
- argenx
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06298552
- Sponsor's protocol ID
- ARGX-113-2308
- Other IDs
- 2024-511796-15-00
- Acronym
- ADAPT SERON
- Status last verified
- Nov 2025
- First submitted
- 1 Mar 2024
- Last updated
- 10 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No