A Safety and Tolerability Study of ARGX-113 in Patients With Myasthenia Gravis Who Have Generalized Muscle Weakness.

Study Overview
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Brief Summary
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This is a Long-Term, Single-Arm, Open-Label, Multicenter Phase 3 follow-on trial of the ARGX-113-1704 study to evaluate the safety and tolerability of ARGX-113 in patients with gMG. Patients who have completed at least 1 cycle of treatment and at least 1 year of trial ARGX-113-1705 and have started Part B are eligible to enroll in the open-label trial ARGX-113-2002 to receive efgartigimod by SC administration.

Official Title
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A Long-Term, Single-Arm, Open-Label, Multicenter, Phase 3 Follow-on Trial of ARGX-113-1704 to Evaluate the Safety and Tolerability of ARGX-113 in Patients With Myasthenia Gravis Having Generalized Muscle Weakness

Conditions
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Generalized Myasthenia Gravis

Intervention / Treatment
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* Biological: ARGX-113


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with the ability to understand the requirements of the trial, provide written informed consent, and comply with the trial protocol procedures. Patients who participated in trial ARGX-113-1704 and are eligible for roll over, as specified in the protocol. Other more specific inclusion criteria are further defined in the protocol. Exclusion Criteria: Patients who discontinued early from trial ARGX-113-1704 or patients who discontinued early from randomized treatment for pregnancy or rescue reasons or an (S)AE that might jeopardize the safety of the patient in that trial. Pregnant and lactating women, and those intending to become pregnant during the trial or within 90 days after the last dosing. Women or childbearing potential should have a negative urine pregnancy test at SEB. Male patients who are sexually active and do not intend to use effective methods of contraception during the trial or within 90 days after the last dosing or male patients who plan to donate sperm during the trial or within 90 days after the last dosing. Patients with known Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) or Human Immunodeficiency Virus (HIV) seropositivity. Other, more specific exclusion criteria are further defined in the protocol.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ARGX-113<br> | Biological: ARGX-113<br>* Intravenous administration of ARGX-113<br>* Other names: efgartigimod;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs, TEAEs Leading to Study Drug Discontinuation and Fatal TEAE in AChR-Positive Participants | An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. Any clinically significant abnormal laboratory test results (hematology, clinical chemistry, or urinalysis) or other safety assessments (electrocardiogram [ECG], radiological scans, vital signs measurements) were collected as AEs. All AEs starting on or after first dose administered and until completion of participant's last visit were considered as TEAEs. A serious AE (SAE) was any AE that resulted in death, was life-threatening, required inpatient hospitalization, resulted in persistent or significant disability/incapacity, was a congenital abnormality, or was medically significant. | TEAEs were collected from the start of first administered study treatment (Day 1) up to end of follow-up, approximately up to 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With TEAEs, Treatment-Emergent SAEs, TEAEs Leading to Study Drug Discontinuation and Fatal TEAE in the Overall Population | Overall population included both AChR-Ab seropositive and AChR-Ab seronegative participants. An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. Any clinically significant abnormal laboratory test results (hematology, clinical chemistry, or urinalysis) or other safety assessments (ECG, radiological scans, vital signs measurements) were collected as AEs. All AEs starting on or after first dose administered and until completion of participant's last visit were considered as TEAEs. An SAE was any AE that resulted in death, was life-threatening, required inpatient hospitalization, resulted in persistent or significant disability/incapacity, was a congenital abnormality, or was medically significant. | TEAEs were collected from the start of first administered study treatment (Day 1) up to end of follow-up, approximately up to 3 years |