ARGX-113

The percentage of patients who do not experience, at any time during the study, a 2 or more-point deterioration from their averaged baseline MG-ADL score that is sustained for a period of 4 or more consecutive weeks. (stable or improved patients)

Free triiodothyronine: \[fT3\]; free thyroxine: \[fT4\]; ATDs: antithyroid drugs

The ESSDAI was designed to measure systemic disease activity in patients with PSjD and consists of 12 domains. The score varies between 0 (no disease activity) and 123 (max disease activity). The clinESSDAI includes all ESSDAI domains except the biological domain.

The Myasthenia Gravis Impairment Index (MGII) is a scoring tool measuring disease severity. It consists of 22 patient-reported outcomes (PRO) and 6 physical examinations (PE). The Ocular PRO score varies between 0 and 18. The higher the score, the more severe the disease.

The Myasthenia Gravis Activities of Daily Living (MG-ADL) scale is an 8-item instrument used to assess MG symptoms and their effects on daily activities. The total score ranges from 0 (no symptoms) to 24 (most severe symptoms).

AE : adverse event ; SAE : serious adverse event ; AESI : adverse event of special interest.

The MG-ADL (Myasthenia Gravis Activities of Daily Living) scale assesses MG symptoms and their effects on daily activities. The total score varies between 0 and 24, with higher total scores indicating more impairment.

AE : adverse event ; SAE : Serious adverse event ; AESI : adverse event of special interest.

Adverse events, Serious Adverse event and Adverse events of special interest. Adverse events in the 'Infections and infestations' SOC were defined as AESIs because efgartigimod causes a transient reduction in total IgG levels.

ANCOVA Analysis of Percent Change From Baseline in Total IgG Level at Day 29 (ie, 7 days after the fourth IV or SC administration).

A participant was considered a responder for this endpoint (i.e., had a sustained platelet count response) if the participant had platelet counts of ≥50 × 10\^9/L for ≥4 of the 6 analysis visits between Weeks 19 and 24.

Proportion of participants with pemphigus vulgaris who had CRmin within 30 weeks, defined as the absence of new lesions and complete healing of established lesions while the participant was receiving prednisone at ≤10 mg/day for at least 8 weeks.

Percentage of participants with chronic ITP with a sustained platelet count response was defined as achieving platelet counts of at least 50 × 10\^9/L for at least 4 of the 6 visits between Week 19 and 24 of the study.

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.

The MG-ADL is an 8-item patient-reported scale to assess MG symptoms and their effects on daily activities. The scale comprises 2 items on daily life activities and 6 items on symptoms. The MG-ADL total score range is 0-24, with higher scores indicative of greater disease severity. A patient was considered an MG-ADL responder during C1 if there was a reduction of ≥2 points on the MG-ADL total score (compared to baseline of C1 \[C1B\]) for ≥4 consecutive weeks with the first reduction occurring no later than 1 week after the last infusion of IMP in C1.

CASE= Clinical Assessment Scale in Autoimmune Encephalitis; NMDAR=N-methyl-D-aspartate receptor; Neuropsychological Status. The CASE (Clinical Assessment Scale in AIE) includes an assessment of 9 items: seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, weakness. This overall CASE total score ranges from 0 to 27, with a higher score indicating a greater degree of disability.

The mTCNS (modified Toronto Clinical Neuropathy Score) is a clinician-reported outcome measure derived from the original TCNS to improve sensitivity to early and mild neuropathy and to enhance feasibility and consistency inclinical research settings. The total mTCNS score is calculated as the sum of the symptom and sensory subscores, yielding a total possible score range of 0 to 33, with higher scores indicating greater neuropathy severity.

The Modified Rodnan Skin Score is a scoring tool to assess skin thickness in 17 cutaneous sites across the body. Each site is rated on a semiquantitative score ranging from 0 (normal) to 3 (severe). The total score is the sum of the individual skin scores and can range from 0 to 51.

An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that, at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration. Adverse events in the 'Infections and infestations' SOC were defined as AE of Special Interest (AESIs) because efgartigimod causes a transient reduction in total IgG levels.

A Composite of Relevant Endpoints for Sjögren's Syndrome (CRESS) responder is defined as improvements in at least 3 of the 5 items of CRESS (systemic disease activity, patient-reported symptoms, tear gland function, salivary gland function and serology. The score ranges from 0 to 9 (higher score = worse symptoms).

Composite Autonomic Symptom Score (COMPASS) 31 modified version (2-week recall) is a self-rated questionnaire to evaluate the severity and distribution of autonomic symptoms in various autonomic nerve disorders. It consists of 31 questions in 6 weighted domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal {GI}-mixed upper and diarrhea, bladder, and pupillomotor). A weighted total score of 0 (mild) to 100 (severe) was determined by adding a maximum raw score for each domain. Higher scores indicated a more severe degree of autonomic symptoms.

The Malmö POTS Symptom Score (MaPS) score is a dedicated POTS symptom scoring questionnaire. The score consists of 12 questions that assess symptom burden related (tachycardia, palpitations, dizziness, presyncope) and unrelated to orthostatic intolerance (GI symptoms, insomnia, concentration difficulties). Participants graded their symptoms for the past 7 days using a visual analog scale ranging from 0 (no symptoms) to 10 (worst possible). The total score was calculated by summing up the items/individual items and range was 0 to 120 points, with higher scores indicating more severe symptoms.

An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that at any dose resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration.

AE : adverse event; SAE : serious adverse event; AESI : adverse event of special interest

CRoff = complete remission while receiving efgartigimod PH20 SC or placebo and being off oral corticosteroid therapy for at least 8 weeks. Complete remission is defined as the absence of new lesions, complete healing of existing lesions and absence of pruritus.

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

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

Total Immunoglobulin G levels will be measured from blood samples

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

Changes from Baseline in vital signs, electrocardiogram parameters (ECGs), physical examination abnormalities and clinical laboratory assessments.

TEAEs were defined as AEs that first occurred or worsened in severity after the first administration of the treatment. A treatment emergent SAE was any untoward medical occurrence that resulted in death; was life-threatening; required inpatient hospitalization or prolongation of existing hospitalization;resulted in persistent or significant disability or incapacity; was a congenital abnormality or birth defect; or other medically significant events. All TEAEs observed were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 4.03 with descriptions of severity for each AE based on the following general guideline: Grade 1= mild; Grade 2 = moderate; Grade 3 = severe or medically significant but not immediately life-threatening; Grade 4 = life-threatening consequences; Grade 5 = death related to AE.

The patients' diastolic and systolic blood pressure were measured pre-dose on dosing days 1,8,15 and 22 and also during the follow up period. The mean change from baseline at each time point is presented. Baseline is defined as the last non-missing value before first dose of study medication.

The patients' heart rate was measured pre-dose on dosing days 1,8,15 and 22 and also during the follow up period. The mean change from baseline at each time point is presented. Baseline is defined as the last non-missing value before first dose of study medication.

The patients' temperature was measured pre-dose on dosing days 1,8,15 and 22 and also during the follow up period. The mean change from baseline at each time point is presented. Baseline is defined as the last non-missing value before first dose of study medication.

The patients' weight as measured pre-dose on dosing days 1,8,15 and 22 and also during the follow up period. The mean change from baseline at each time point is presented. Baseline is defined as the last non-missing value before first dose of study medication.

ECG parameters of heart rate, PR, QT, and QRS interval were read locally and performed pre-dose on dosing days 1,8,15 and 22 and on the last follow up visit on Day 78. Any patients recording abnormal clinically relevant findings during the study are presented.

Sampling for clinical laboratory tests including hematology, clinical chemistry, and urinalysiswas performed pre-dose on dosing Days 1, 8, 15 and 22 and throughout the follow up period. Patients fasted for at least 8 hours prior to this sampling. Abnormal laboratory values, or test results were not reported as TEAEs unless they were associated with clinical signs and symptoms that were considered clinically relevant, required therapy or led to treatment discontinuation. Patients reporting TEAEs in any of the laboratory parameters during the study are presented.

The proportion of patients who exhibit reduction in serum C7 antibody levels at week 26 as compared to week 1.

Occurrence of adverse events and effects.

The overall improvement of EB symptoms at week 26 as compared to week 1, measured by percentage change of a participant's EBDASI score (overall total score, total activity score, and total damage score). The EBDASI is scored in the range of 0 - 506, with a lower score corresponding to mild disease and higher score corresponding to more severe disease.