Evaluating Long-term Safety of Efgartigimod Administered Intravenously and Efgartigimod PH20 Administered Subcutaneously in Children with Generalized Myasthenia Gravis

Phase 2

• Conditions: Generalized Myasthenia Gravis
• Interventions: Biological: Efgartigimod IV or Efgartigimod PH20 SC

• Registration Number: NCT05374590
• Lead Sponsor: argenx

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-04-01
• Study First Submitted QC: 2022-05-13
• Study First Posted: 2022-05-16
• Study Start: 2022-08-18
• Status Verified: 2025-02
• Last Update Submitted: 2025-02-28
• Last Update Posted: 2025-03-03
• Primary Completion: 2028-09
• Study Completion: 2028-09

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 12

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Efgartigimod or Efgartigimod PH20 SC	Efgartigimod IV or Efgartigimod PH20 SC	Patients receiving Efgartigimod IV treatment or Efgartigimod PH 20 SC treatment

Primary Outcome Measures

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

Secondary Outcome Measures

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

Trial Locations

Locations (10)

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

Universitair Ziekenhuis Antwerpen; 🇧🇪 Edegem, Belgium

Ann and Robert H Lurie Children's Hospital of Chicago - Main Hospital; 🇺🇸 Chicago, Illinois, United States

University of Virginia (UVA) Health - Developmental Pediatrics Clinic; 🇺🇸 Charlottesville, Virginia, United States

Leids Universitair Medisch Centrum; 🇳🇱 Leiden, Netherlands

Uniwersyteckie Centrum Kliniczne w Gdansku; 🇵🇱 Gdańsk, Poland

Wielospecjalistyczna Poradnia Lekarska Synapsis; 🇵🇱 Katowice, Poland

Centralny Szpital Kliniczny - Uniwersyteckie Centrum Kliniczne WUM; 🇵🇱 Warszawa, Poland

Great Ormand Street Hospital for Children NHS Foundation Trust - Great Ormond Street Hospital - Pediatric Neurology; 🇬🇧 London, United Kingdom

Oxford University Hospitals NHS Foundation Trust - John Radcliffe Hospital Children's Hospital; 🇬🇧 Oxford, United Kingdom