Evaluating Long-term Safety of Efgartigimod Administered Intravenously and Efgartigimod PH20 Administered Subcutaneously in Children With Generalized Myasthenia Gravis (ADAPT Jr +)

A Long-term, Single-Arm, Open-label, Multicenter Trial to Evaluate Safety of Efgartigimod Administered Intravenously and Efgartigimod PH20 Administered Subcutaneously in Children With Generalized Myasthenia Gravis

The purpose of this trial is to evaluate the long-term safety of efgartigimod IV and efgartigimod PH20 SC administered to participants with gMG in the antecedent studies, ARGX-113-2006 and ARGX-113-2207, respectively.

Study Overview

• Status: Recruiting
• Conditions: Generalized Myasthenia Gravis
• Intervention / Treatment: Biological: Efgartigimod IV or Efgartigimod PH20 SC

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Phase 2; Phase 3

Contacts and Locations

• Study Contact: Name: Sabine Coppieters, MD; Phone Number: 857-350-4834; Email: clinicaltrials@argenx.com

Study Locations

• Belgium
  • Antwerp, Belgium, 2650
    • Recruiting
    • UZ Antwerpen
    • Contact: Diane Beysen, MD; Phone Number: 857-350-4834; Email: Clinicaltrials@argenx.com
• Netherlands
  • Leiden, Netherlands, 2333
    • Recruiting
    • Leiden University Medical Center
    • Contact: Erik Harmen Niks, MD; Phone Number: 8573504834; Email: clinicaltrials@argenx.com
• Poland
  • Katowice, Poland, 40-123
    • Recruiting
    • Wielospecjalistyczna Poradnia Lekarska SYNAPSIS
    • Contact: Marek Smilowski, MD; Phone Number: 8573504834; Email: clinicaltrials@argenx.com
  • Warszawa, Poland, 02-097
    • Recruiting
    • Uniwersyteckie Centrum Kliniczne WUM, Centralny Szpital Kliniczny
    • Contact: Anna Kostera-Pruszczyk, MD; Phone Number: 8573504834; Email: clinicaltrials@argenx.com
• United Kingdom
  • Oxford, United Kingdom, OX3 9DU
    • Recruiting
    • Oxford University hospitals NHS Foundation Trust-Oxford Children's Hospital
    • Contact: Sithara Ramdas, MD; Phone Number: 857-350-4834; Email: clinicaltrials@argenx.com
• United States
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Recruiting
      • Ann and Robert H. Lurie Childrens Hospital of Chicago
      • Contact: Nancy Kuntz, MD; Phone Number: 857-350-4834; Email: Clinicaltrials@argenx.com
  • Virginia
    • Charlottesville, Virginia, United States, 22903
      • Recruiting
      • University of Virginia
      • Contact: Anna Jesus, MD; Phone Number: 857-350-4834; Email: Clinicaltrials@argenx.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 2 years to 18 years (Child, Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Participants are eligible to be included in the trial only if all of the following criteria apply:

1. The participant completed ARGX-113-2006 or ARGX-113-2207, defined as:

   1. The participant reached End of Trial in trial ARGX-113-2006 or End of Study in ARGX-113-2207 and agreed to participate in the ARGX-113-2008 trial.
   2. The participant qualifies for retreatment in trial ARGX-113-2006, but cannot complete a Treatment Period (TP) and the required Intertreatment Period (IP) visits within the ARGX-113-2006 trial's timeframe.
2. Either the participant or the participant's legally authorized representative can understand the requirements of the trial and provide written informed consent/assent, and willingness and ability to comply with the trial protocol procedures.

3. Contraceptive use for sexually active participants should be consistent with local regulations for those participating in clinical studies. A participant is of childbearing potential if, in the opinion of the investigator, he/she is biologically capable of having children.

   1. Contraceptive requirements for male participants are presented in Section 10.4.2.2.
   2. Female adolescents of childbearing potential (FAOCBP) must have a negative urine pregnancy test at trial entry (TP1V1 or IP0V1)

Exclusion Criteria:

Participants are excluded from the trial if any of the following criteria apply:

1. Female adolescents of childbearing potential (FAOCBP): Pregnancy or lactation, or the participant intends to become pregnant during their participation in the study.
2. Discontinued early from ARGX-113-2006 or ARGX-113-2207 treatment.
3. A known hypersensitivity reaction to efgartigimod or any of its excipients.

4. Any of the following medical conditions:

   1. Clinically significant uncontrolled chronic bacterial, viral, or fungal infection at study entry not sufficiently resolved in the investigator's opinion.
   2. Known autoimmune disease or any medical condition that would interfere with an accurate assessment of clinical symptoms of generalized myasthenia gravis (gMG) or put the participant at undue risk

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Efgartigimod or Efgartigimod PH20 SC; Patients receiving Efgartigimod IV treatment or Efgartigimod PH 20 SC treatment	Biological: Efgartigimod IV or Efgartigimod PH20 SC; Intravenous infusion of Efgartigimod or Subcutaneous injection of Efgartigimod PH20 SC

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Incidence of adverse events (AEs)	up to 4 years
Severity of adverse events (AEs)	up to 4 years
Incidence of serious adverse events (SAEs)	up to 4 years
Severity of serious adverse events (SAEs)	up to 4 years
Incidence of adverse events of special interest (AESIs)	up to 4 years
Severity of adverse events of special interest (AESIs)	up to 4 years
Changes in height from baseline	up to 4 years
Changes in weight from baseline	up to 4 years
Electrocardiogram - heart rate	up to 4 years
Electrocardiogram - QTcF (ms)	up to 4 years

Secondary Outcome Measures

Outcome Measure	Time Frame
Incidence of antidrug antibodies (ADAs) against efgartigimod	up to 4 years
Prevalence of antidrug antibodies (ADAs) against efgartigimod	up to 4 years
Incidence of antibodies against recombinant human hyaluronidase PH20 (rHuPH20)	Up to 4 years
Prevalence of antibodies against recombinant human hyaluronidase PH20 (rHuPH20)	Up to 4 years

Collaborators and Investigators

• Sponsor: argenx

Study record dates

Study Major Dates

• Study Start (Actual): August 18, 2022
• Primary Completion (Estimated): September 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: April 1, 2022
• First Submitted That Met QC Criteria: May 13, 2022
• First Posted (Actual): May 16, 2022

Study Record Updates

• Last Update Posted (Actual): April 11, 2024
• Last Update Submitted That Met QC Criteria: April 10, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Nervous System Diseases; Immune System Diseases; Neoplasms; Autoimmune Diseases of the Nervous System; Autoimmune Diseases; Neoplasms by Site; Neurologic Manifestations; Musculoskeletal Diseases; Muscular Diseases; Neuromuscular Diseases; Neurodegenerative Diseases; Neuromuscular Manifestations; Nervous System Neoplasms; Paraneoplastic Syndromes, Nervous System; Paraneoplastic Syndromes; Neuromuscular Junction Diseases; Muscle Weakness; Myasthenia Gravis
• Other Study ID Numbers: ARGX-113-2008

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes