An Open-label Study to Investigate the Clinical Efficacy of Different Dosing Regimens of Efgartigimod IV in Patients With Generalized Myasthenia Gravis

NCT04980495 | Completed Phase 3 DMC FDA Drug

• 2 other identifiers: ARGX-113-20032024-510932-36-00
• Study Type: interventional
• Target: 69
• Locations: 11 countries
• Sites: 39

Brief Summary

The purpose of this open-label study is to investigate the efficacy, safety, and tolerability of a continuous regimen of efgartigimod compared with a cyclic regimen in participants with Generalized Myasthenia Gravis (gMG). Participants will receive efgartigimod throughout the study. The participants will be randomized to the continuous regimen arm or to the cyclic regimen arm. The study consists of a part A (regimen comparison period) where participants will continue the treatment based on the treatment regimen arm they were assigned at randomization. Following part A, participants will enter part B (extension period) where all participants will receive efgartigimod in the continuous regimen. The study duration for participants is up to 138 weeks.

Conditions

Generalized Myasthenia Gravis; MG - Myasthenia Gravis; gMG

Outcome Measures

Primary Outcomes (1)

• Mean of the average MG-ADL total score change from baseline during the visit of week 1 through week 21 by regimen arm

  The MG-ADL (Myasthenia Gravis Activities of Daily Living) scale assesses MG symptoms and their effects on daily activities. The total score varies between 0 and 24, with higher total scores indicating more impairment.

  Up to 21 weeks

Secondary Outcomes (7)

• Incidence of AEs, SAEs and AESIs

  Up to 136 weeks

• Change from baseline in the MG-ADL total score over time

  Up to 126 weeks

• Normalized area under the effect curve (AUEC) of MG-ADL total score improvement from baseline

  Up to 21 weeks

• Characterization of MG-ADL total score change from baseline

  Up to 21 weeks

• Percentage of participants who have a ≥ 2, 3, 4, or 5 points improvement in MG-ADL total score from baseline

  Up to 21 weeks

Study Arms (2)

Efgartigimod IV - continuous regimen

EXPERIMENTAL

Participants receiving efgartigimod IV on a continuous regimen

Biological: Efgartigimod IV

Efgartigimod IV - cyclic regimen

EXPERIMENTAL

Participants receiving efgartigimod IV on a cyclic regimen

Biological: Efgartigimod IV

Interventions

Efgartigimod IV BIOLOGICAL

Intravenous infusions of efgartigimod

Efgartigimod IV - continuous regimen; Efgartigimod IV - cyclic regimen

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• At least 18 years of age, at the time of signing the informed consent.
• Diagnosed with Generalized Myasthenia Gravis (gMG) with confirmed documentation and supported by a physical exam and confirmed seropositivity for anti-acetylcholine receptor antibodies (AChR-Abs).
• Meets the clinical criteria as defined by the Myasthenia Gravis Foundation of America (MGFA) class II, III, or IV

You may not qualify if:

• Any other condition that, in the opinion of the investigator, would interfere with an accurate assessment of the clinical symptoms of gMG and/or put the participant at undue risk
• A thymectomy within 3 months of screening
• Use of the following prior or concomitant therapies:
• intravenous immunoglobulin (IVIg) or subcutaneous immunoglobulin (SCIg) within 14 days of day 1
• Rituximab within 6 months of day 1
• Eculizumab within 1 month of day 1
• Other monoclonal antibodies (eg, adalimumab, tocilizumab, ixekizumab)

Sponsors & Collaborators

• argenx: lead

Study Sites (39)

Investigator Site 10 - US0010007

Carlsbad, California, 92011, United States

Location

Investigator Site 7 - US0010001

Orange, California, 92868, United States

Location

Investigator Site 9 - 0010006

Boca Raton, Florida, 33487, United States

Location

Investigator Site 15 - US0010014

Coral Springs, Florida, 33067, United States

Location

Investigator Site 16 - US0010009

Augusta, Georgia, 30910, United States

Location

Investigator Site 8 - US0010003

Chicago, Illinois, 60611, United States

Location

Investigator Site 6 - US0010008

Meadows, Illinois, 60008, United States

Location

Investigator Site 12 - US0010004

Kansas City, Kansas, 66160, United States

Location

Investigator Site 13 - US0010013

Portland, Oregon, 97239, United States

Location

Investigator Site 17 - US0010012

Philadelphia, Pennsylvania, 19104, United States

Location

Investigator Site 11 - US0010011

Austin, Texas, 78756, United States

Location

Investigator Site 14 - US0010010

Richmond, Virginia, 23219, United States

Location

Investigator Site 26 - AT0430002

Innsbruck, 6020, Austria

Location

Investigator Site 27 - AT0430001

Vienna, 1090, Austria

Location

Investigator Site 28 - BE0320001

Leuven, 3000, Belgium

Location

Investigator Site 29 - CA0019003

London, N6A 5A5, Canada

Location

Investigator site 37 - CA0019002

Québec, H3A 2B4, Canada

Location

Investigator Site 23 - FR0330005

Bordeaux, 33604, France

Location

Investigator Site 24 - FR0330004

Lille, 59000, France

Location

Investigator Site 20 - FR0330001

Marseille, 13385, France

Location

Investigator Site 25 - FR0330003

Nice, 06001, France

Location

Investigator site 38 - FR0330002

Paris, 75013, France

Location

Investigator Site 2 - GEO9950002

Tbilisi, 0112, Georgia

Location

Investigator Site 1 - GEO9950001

Tbilisi, 0114, Georgia

Location

Investigator Site 3 - GEO9950003

Tbilisi, 0114, Georgia

Location

Investigator Site 33 - DE0490004

Berlin, 10117, Germany

Location

Investigator Site 36 - DE0490002

Bochum, 44791, Germany

Location

Investigator Site 32 - DE0490001

Essen, 45147, Germany

Location

Investigator Site 34 - DE0490005

Hanover, 30625, Germany

Location

Investigator Site 31 - IT0390005

Bologna, 40139, Italy

Location

Investigator Site 30 - IT0390004

Genova, 16132, Italy

Location

Investigator Site 21 - IT0390002

Milan, 20133, Italy

Location

Investigator site 39 - IT0390006

Pisa, 56126, Italy

Location

Investigator Site 22 - IT0390001

Roma, 00168, Italy

Location

Investigator Site 35 - NL0310001

Amsterdam, 1105, Netherlands

Location

Investigator Site 5 - PL0480002

Krakow, 31-426, Poland

Location

Investigator Site 4 - PL0480001

Lubin, 20-093, Poland

Location

Investigator Site 18 - ES0340002

Santiago de Compostela, A Coruña, 15706, Spain

Location

Investigator Site 19 - ES0340001

Barcelona, 08041, Spain

Location

MeSH Terms

Conditions

Myasthenia Gravis

Condition Hierarchy (Ancestors)

Paraneoplastic Syndromes, Nervous System; Nervous System Neoplasms; Neoplasms by Site; Neoplasms; Paraneoplastic Syndromes; Autoimmune Diseases of the Nervous System; Nervous System Diseases; Neurodegenerative Diseases; Neuromuscular Junction Diseases; Neuromuscular Diseases; Autoimmune Diseases; Immune System Diseases

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 19, 2021
• First Posted: July 28, 2021
• Study Start: December 16, 2021
• Primary Completion: August 24, 2023
• Study Completion: October 6, 2025
• Last Updated: November 5, 2025

Record last verified: 2025-11

Locations

AU (2); IT (5); ES (2); BE (1); CA (2); GE (3); US (12); DE (4); PL (2); FR (5); NL (1)