Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously in Patients With Generalized Myasthenia Gravis

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the long-term safety and tolerability of efgartigimod PH20 SC 1000 mg, and the clinical efficacy, PD, pharmacokinetics (PK), immunogenicity, impact on the quality of life (QoL) of the participants, treatment satisfaction, and administration method preference, and the feasibility of self- and caregiver-supported administration of the SC injection. Treatment duration: 3-week treatment periods, repeated as needed with at least 28 days in between treatment periods Health measurements: total levels of immunoglobulin G (IgG), Acetylcholine receptor binding autoantibodies (AChR-Ab) levels, Myasthenia Gravis Activities of Daly Living (MG-ADL).

Official Title
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A Long-Term, Single-Arm, Open-label, Multicenter Phase 3 Study to Evaluate the Safety and Tolerability of Multiple Subcutaneous Injections of Efgartigimod PH20 SC in Patients With Generalized Myasthenia Gravis

Conditions
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Generalized Myasthenia Gravis

Intervention / Treatment
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* Biological: efgartigimod PH20 SC


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Must be capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. Previously participated in antecedent studies ARGX-113-2001 or ARGX-113-1705 and are eligible for roll over. Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies and: Women of Child bearing potential (WOCBP) must have a negative urine pregnancy test at baseline before investigational medicinal product (IMP) can be administered. Exclusion Criteria: The participant was discontinued early from studies ARGX-113-2001 or ARGX-113-1705, unless the reason for discontinuation from study ARGX-113-1705 was to roll over into study ARGX-113-2002. a. Participants who, in the investigator's judgment, are not benefiting from efgartigimod IV in study ARGX-113-1705 Part B are not eligible for roll over into ARGX-113-2002. Are pregnant or lactating, or intend to become pregnant during the study or within 90 days after the last dose of investigational medicinal product (IMP) Has any of the following medical conditions: Clinically significant uncontrolled chronic bacterial, viral, or fungal infection at roll-over Any other known autoimmune disease that, in the opinion of the investigator, would interfere with 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 reoccurrence for ≥3 years before the first administration of investigational medicinal product (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 (TNM classification of malignant tumors stage T1a or T1b) Clinical evidence of other significant serious diseases, or the participant has had a recent major surgery, or who have any other condition that, in the opinion of the investigator, could confound the results of the study or put the participant at undue risk Received a live-attenuated vaccine within 28 days prior to study entry or plan to receive a live-attenuated vaccine during the study A known hypersensitivity reaction to efgartigimod, rHuPH20, or any of its excipients

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: efgartigimod PH20 SC<br>Patients receiving efgartigimod PH20 subcutaneous (SC) treatment | Biological: efgartigimod PH20 SC<br>* Subcutaneous injection with efgartigimod PH20 SC<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence and severity of Adverse Events (AEs) |  | Up to 3.5 years | 
| Incidence of Serious Adverse Events (SAEs) |  | Up to 3.5 years | 
| Incidence of Adverse Events of Special Interest (AESI) |  | Up to 3.5 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Myasthenia Gravis Activities of Daily Living (MG-ADL) total score changes from baseline | the higher the score, the more impairment | Up to 3.5 years | 
| Cycle baseline over time by cycle (for MG-ADL) |  | Up to 3.5 years | 
| Percentage change in levels of total immunoglobulin G (IgG) from baseline |  | Up to 3.5 years | 
| Cycle baseline over time by cycle (for total immunoglobulin G (IgG) |  | Up to 3.5 years | 
| Percentage change of anti-acetylcholine receptor antibodies (AChR-Ab) from baseline |  | Up to 3.5 years | 
| Cycle baseline over time by cycle in AChR-Ab seropositive participants (for acetylcholine receptor binding autoantibodies (AChR-Ab)) |  | Up to 3.5 years | 
| Efgartigimod serum concentrations |  | Up to 3.5 years | 
| Incidence of anti-drug antibodies (ADAs) to efgartigimod over time |  | Up to 3.5 years | 
| Prevalence of anti-drug antibodies (ADAs) to efgartigimod over time |  | Up to 3.5 years | 
| Incidence of neutralizing antibodies (NAbs) against efgartigimod over time |  | Up to 3.5 years | 
| Prevalence of neutralizing antibodies (NAbs) against efgartigimod over time |  | Up to 3.5 years | 
| Incidence of ADAs to rHuPH20 over time |  | Up to 3.5 years | 
| Prevalence of ADAs to rHuPH20 over time |  | Up to 3.5 years | 
| Incidence of NAbs against rHuPH20 over time |  | Up to 3.5 years | 
| Prevalence of NAbs against rHuPH20 over time |  | Up to 3.5 years | 
| Changes in total Myasthenia Gravis Quality of Life Questionnaire (15-item scale revised) (MG-QoL15r) from baseline |  | Up to 3.5 years | 
| Cycle baseline by cycle (for MG-QoL15r) |  | Up to 3.5 years | 
| Changes in EuroQoL 5 Dimensions 5-Level (EQ-5D-5L) visual analog scale (VAS) score from baseline |  | Up to 3.5 years | 
| Cycle baseline by cycle (for EQ-5D-5L) |  | Up to 3.5 years | 
| EQ-5D-5L responses over time by cycle |  | Up to 3.5 years | 
| Number of participants who performed self-administration at home over time by cycle |  | Up to 3.5 years | 
| Percentage of participants who performed self-administration at home over time by cycle |  | Up to 3.5 years | 
| Number of caregivers who administered the injection to the participant at home over time by cycle |  | Up to 3.5 years | 
| Percentage of caregivers who administered the injection to the participant at home over time by cycle |  | Up to 3.5 years | 
| Number of training visits needed for the participant or caregiver to be competent to start administering efgartigimod PH20 SC |  | Up to 3.5 years | 
| Number of self- or caregiver-supported study drug administration among all study treatment visits at home |  | Up to 3.5 years | 
| Percentage of self- or caregiver-supported study drug administration among all study treatment visits at home |  | Up to 3.5 years |