Evaluating the Pharmacokinetics, Pharmacodynamics, and Safety of Efgartigimod Administered Intravenously in Children With Generalized Myasthenia Gravis

NCT04833894 | Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: ARGX-113-20062024-513854-31-00
• Study Type: interventional
• Target: 12
• Locations: 12 countries
• Sites: 25

Brief Summary

The purpose of this trial is to investigate the PK, PD, safety, and activity of efgartigimod IV in children and adolescents aged from 2 to less than 18 years of age with gMG. Trial details include:

• The maximum trial duration for each individual participant will be approximately 28 weeks
• The treatment duration will be 8 weeks for the dose-confirmatory part (Part A) and 18 weeks for the treatment response-confirmatory part (Part B)

Conditions

Generalized Myasthenia Gravis

Outcome Measures

Primary Outcomes (4)

• Efgartigimod concentrations as input for compartmental, model-driven analysis to determine (age and size dependency of) Clearance (CL)

  Blood samples will be collected from each participant for measurement of serum concentrations of efgartigimod

  up to 26 weeks

• Efgartigimod concentrations as input for compartmental, model-driven analysis to determine (age and size dependency of) Volume of Distribution (Vd)

  Blood samples will be collected from each participant for measurement of serum concentrations of efgartigimod

  up to 26 weeks

• Total Immunoglobulin G (IgG) levels as input for pharmacokinetics (PK) and pharmacodynamics (PD) modeling analysis

  Total Immunoglobulin G levels will be measured from blood samples

  up to 26 weeks

• Anti-acetylcholine receptors antibodies (AChR-Ab) as input for pharmacokinetics (PK) and pharmacodynamics (PD) modeling analysis

  Total Immunoglobulin G (IgG) levels will be measured from blood samples

  up to 26 weeks

Secondary Outcomes (19)

• Incidence and severity of adverse events (AEs), serious adverse events (SAEs) and adverse events of special interest (AESIs)

  up to 28 weeks

• Efgartigimod serum concentrations from blood samples

  up to 26 weeks

• Absolute values of levels of total Immunoglobulin G (IgG) from blood samples

  up to 26 weeks

• Change from baseline of levels of total Immunoglobulin G (IgG) from blood samples

  up to 26 weeks

• Percentage change from baseline of total Immunoglobulin G (IgG) from blood samples

  up to 26 weeks

Study Arms (1)

Efgartigimod

EXPERIMENTAL

Patients receiving efgartigimod intravenous (IV) treatment

Biological: Efgartigimod IV

Interventions

Efgartigimod IV BIOLOGICAL

Intravenous infusion of Efgartigimod

Efgartigimod

Eligibility Criteria

• Age: 2 Years - 18 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Ability of the participant and/or his/her legally authorized representative to understand the requirements of the trial and provide written informed consent/assent, if applicable (including consent/assent for the use and disclosure of research-related health information), willingness and ability to comply with the trial protocol procedures (including attending the required trial visits).
• Male or female participants between 2 to less than 18 years of age at the time of providing informed consent/assent. Age groups are enrolled in a staggered fashion respectively: 6 participants in the 12 to less than 18 years of age group followed by 6 participants in the 2 to less than 12 years of age group at the time of providing informed consent/assent.
• Diagnosed with Generalized Myasthenia Gravis (gMG) with confirmed documentation
• Meeting the clinical criteria as defined by the Myasthenia Gravis Foundation of America (MGFA) class II, III, and IVa.
• Eligible participants should have an unsatisfactory response (efficacy and/or safety) to immunosuppressants, steroids or acetylcholinesterase (AChE) inhibitors and should be on stable concomitant gMG therapy of adequate duration before screening.
• Positive serologic test for acetylcholine receptor (anti-AChR) antibodies at screening (for younger participants (\<15kg) historical values can be used).
• Contraceptive use should be consistent with local regulations regarding the methods of contraception for those participating in clinical trials. A subject is of childbearing potential if, in the opinion of the investigator, he/she is biologically capable of having children and is sexually active.
• Male participants: Male participants must agree to not donate sperm from of providing informed consent/assent until they have completed the trial.
• Female participants: Female adolescents of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test at baseline before investigational medicinal product (IMP) can be administered.

You may not qualify if:

• Participants with MGFA class I, IVb, and V.
• Female adolescents of childbearing potential: Pregnancy or lactation, or the participant intends to become pregnant during the trial or within 90 days after the last dose of IMP.
• Has any of the following medical conditions:
• Clinically significant uncontrolled active or chronic bacterial, viral, or fungal infection at screening.
• Any other known autoimmune disease that, in the opinion of the investigator, would interfere with an accurate assessment of clinical symptoms of myasthenia gravis or put the participant at undue risk.
• History of malignancy unless deemed cured by adequate treatment with no evidence of recurrence for ≥3 years before the first administration of IMP. Participants with the following cancers can be included at any time: Adequately treated 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
• Clinical evidence of other significant serious diseases, or have had a recent major surgery, or who have any other condition that, in the opinion of the investigator, could confound the results of the trial or put the participant at undue risk
• Worsening muscle weakness secondary to concurrent infections or medications (aminoglycosides, fluoro-quinolones, beta-blockers, etc).
• A documented lack of clinical response to plasma exchange (PLEX).
• Received a thymectomy \<3 months before screening or 1 is planned to be performed during the trial period.
• a. Positive serum test at screening for an active viral infection with any of the following conditions: Hepatitis B virus (HBV) that is indicative of an acute or chronic infection; Hepatitis C virus (HCV) based on HCV antibody assay; Positive HIV serology at screening; Positive nasopharyngeal swab polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at screening.
• Using the following prior or concomitant therapies: Use of an investigational product within 3 months or 5 half-lives (whichever is longer) before the first dose of IMP, Use of any monoclonal antibody within the 6 months before the first dose of IMP, Use of intravenous immunoglobulin (IVIg), administered subcutaneously or intramuscularly, or PLEX within 4 weeks before screening.
• Total immunoglobulin (IgG) levels \<6 g/L below the lower limit of normal (LLN) according to the reference ranges of the central laboratory for participant by sex and age at screening.
• A known hypersensitivity reaction to efgartigimod or any of its excipients.
• Current participation in another interventional clinical trial or previous participation in an efgartigimod trial with at least 1 dose of IMP received.

Sponsors & Collaborators

• argenx: lead

Study Sites (25)

Ann and Robert H Lurie Children's Hospital of Chicago - Main Hospital

Chicago, Illinois, 60611, United States

RECRUITING

University of North Carolina at Chapel Hill

Chapel Hill, North Carolina, 27599, United States

RECRUITING

University of Virginia (UVA) Health - Developmental Pediatrics Clinic

Charlottesville, Virginia, 22903, United States

RECRUITING

Medizinische Universitat Wien

Vienna, 1090, Austria

COMPLETED

Universitair Ziekenhuis Antwerpen

Antwerp, 2650, Belgium

RECRUITING

Alberta Childrens Hospital

Calgary, T3B 6A8, Canada

RECRUITING

British Columbia Children's Hospital

Vancouver, V6H 3N1, Canada

RECRUITING

AP-HM - Hopital de la Timone

Marseille, 13385, France

RECRUITING

Assistance Publique Hopitaux de Paris (AP-HP) - Hopital Necker-Enfants Malades

Paris, 75015, France

RECRUITING

Vian - M. Iashvili Children's Central Hospital

Tbilisi, 121, Georgia

COMPLETED

Tbilisi State Medical University - Givi Zhvania Pediatric Academic Clinic

Tbilisi, 159, Georgia

COMPLETED

Charite Universitaetsmedizin Berlin - Campus Virchow-Klinikum - Sozialpadiatrisches Zentrum

Berlin, 13353, Germany

COMPLETED

Universitätsklinikum Essen

Essen, 45147, Germany

COMPLETED

Azienda Ospedaliera Universitaria Policlinico Consorziale Di Bari

Bari, 70124, Italy

RECRUITING

Azienda Ospedaliero Universitaria A. Meyer

Florence, 50139, Italy

RECRUITING

Ospedale Giannina Gaslini

Genova, 16147, Italy

RECRUITING

Leids Universitair Medisch Centrum

Leiden, 2333 ZA, Netherlands

RECRUITING

Uniwersyteckie Centrum Kliniczne

Gdansk, Woj. Pomorskie, 80-952, Poland

RECRUITING

Wielospecjalistyczna Poradnia Lekarska Synapsis

Katowice, Woj. Slaskie, 40-123, Poland

RECRUITING

Centralny Szpital Kliniczny - Uniwersyteckie Centrum Kliniczne WUM

Warsaw, 02-097, Poland

RECRUITING

Hospital Sant Joan de Deu

Esplugues de Llobregat, 08950, Spain

RECRUITING

Hospital Universitari i Politecnic La Fe de Valencia

Valencia, 46026, Spain

RECRUITING

Great Ormand Street Hospital for Children NHS Foundation Trust - Great Ormond Street Hospital

London, WC1N 3JH, United Kingdom

RECRUITING

Manchester University NHS Foundation Trust - Royal Manchester Children's Hospital

Manchester, M13 9WL, United Kingdom

RECRUITING

Oxford University Hospitals NHS Foundation Trust - John Radcliffe Hospital Children's Hospital

Oxford, OX3 9DU, United Kingdom

RECRUITING

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

Central Study Contacts

Sabine Coppieters, MD

CONTACT

857-350-4834; ClinicalTrials@argenx.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 16, 2021
• First Posted: April 6, 2021
• Study Start: October 26, 2021
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: February 18, 2026

Record last verified: 2026-02

Locations

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