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
Phase: PHASE3
Conditions: Generalized Myasthenia Gravis
Sponsor: argenx



Clinical Trial Protocol Version 4.0, Final 
 
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Contract Research Organization 
(CRO): 
Syneos Health™ group company 
including INC Research, LLC, together with INC 
Research UK Limited 
3201 Beechleaf Court 
Suite 600 
Raleigh, North Carolina 27604-1547 
USA 
Phone: +1 919 876 9300 
The following additional numbers are also available for urgent contact 
24-Hour Urgent Medical Helpline 
Number: 
+1 877 462 0134 
For drug-safety reporting, contact the below email address 
Safety Mailbox/Fax: 
Email: 248700ADR@parexel.com  
Fax: +1 833 644 0806 
Confidentiality Statement 
This confidential information in this document is provided to you as an investigator or consultant 
for review by you, your staff, and the applicable Institutional Review Board/Independent Ethics 
Committee. Your acceptance of this document constitutes agreement that you will not disclose 
the information contained herein to others without written authorization from the sponsor. 
 
 
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SIGNATURE OF INVESTIGATOR 
PROTOCOL TITLE: 
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 
PROTOCOL NO: 
 
ARGX-113-1705 (ADAPT+) 
This protocol is a confidential communication of argenx BVBA. I confirm that I have read this 
protocol, I understand it, and I will work according to this protocol. I will also work consistently 
with the ethical principles that have their origin in the Declaration of Helsinki and that are 
consistent with good clinical practices and the applicable laws and regulations. Acceptance of 
this document constitutes my agreement that no unpublished information contained herein will 
be published or disclosed without prior written approval from argenx BVBA. 
 
Instructions to the investigator: Please SIGN and DATE this signature page. PRINT your 
name, title, and the name of the site in which the trial will be conducted. Return the signed 
original copy to the local representative of your sponsor’s designated CRO. 
 
I have read this protocol in its entirety and agree to conduct the trial accordingly: 
Signature of Investigator: 
 
Date: 
 
Printed Name: 
 
 
 
Investigator Title: 
 
 
 
Name/Address of Site: 
 
 
 
 
 
 
 
 
 
 
 
 
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DOCUMENT HISTORY 
Previous Version Number 
Effective Date 
Protocol Version 1.0 
15 June 2018 
Protocol Version 2.0 
12 August 2019 
Protocol Version 3.0 
18 December 2019 
Protocol Version 3.1 
15 April 2020 
Protocol Version 3.2 
30 June 2020 
Protocol Version 4.0 
19 January 2021 
SUMMARY OF CHANGES 
Changes from Protocol Version 3.2 compared to Protocol Version 4.0 are summarized below. 
Note: updates to headers/footers and the tables of contents and editorial changes to layout, font, 
format, and style guide conventions are not captured in this summary. 
Section 
Change 
Rationale 
Safety Mailbox/Fax: 
Email: be.life.saefax-ma@sgs.com 
Fax: +32 (0)15 29 93 94 
changed to 
Email: 248700ADR@parexel.com 
Fax: +1 1 833 644-0806 
Parexel is replacing SGS as 
the CRO for safety reporting. 
Appendix 4 Administrative 
Structure 
Added vendor for study monitoring 
EastHORN Clinical Service GmbH 
Im Mediapark 6c 
50670 Cologne 
Germany 
Corrected an omission of a 
monitoring vendor 
Data Management, Biostatistics, Drug Safety 
Reporting 
changed to 
Data Management and Biostatistics 
SGS is the CRO for data 
management and biostatistics. 
Parexel is the CRO for drug 
safety reporting. 
Row added for safety reporting vendor 
Drug Safety Reporting 
Parexel International 
8 Federal Street 
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Section 
Change 
Rationale 
Billerica MA 01821 
United States 
Throughout document 
ARGX-113 
changed to 
efgartigimod 
ARGX-113 has been changed 
to efgartigimod throughout the 
document to be current with 
the clinical development 
program. 
1.4. Benefit-Risk Assessment 
The section has been revised. 
Updated benefit-risk 
assessment based on emerging 
data and consistency with IB 
v9.0 
4.1. Summary of Trial Design 
Other sections impacted by 
the added text: 
x Synopsis 
x Table 2 General Schedule 
of Assessments for Part B 
x Figure 2 ARGX-113-1705 
Trial Design for Part B 
x Section 1.4 Benefit-Risk 
Assessment 
x 4.2. Discussion of Trial 
Design 
Added text: 
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. 
Before enrolling in ARGX-113-2002 from 
Part B, patients must first complete the early 
discontinuation (ED) visit assessments 
specified in Table 2. The previous 
efgartigimod IV dose must have been received 
at least 30 days before entry into ARGX-113-
2002. 
Patients can enroll in ARGX-113-2002 until 
recruitment for this study is closed. Patients 
who enroll in ARGX-113-2002 will not return 
to ARGX-113-1705. 
To allow patients to enroll in 
the safety study ARGX-113-
2002 
4.4. Early Discontinuation 
Other sections impacted by 
the changed text: 
x 5.4 End of Part A, End of 
Study and Early 
Discontinuation Visit 
…contact those patients who do not return for 
scheduled visits. 
The reason for early discontinuation from the 
trial will be clearly documented by the 
Investigator. 
Changed to 
…contact those patients who do not return for 
scheduled visits. 
Patients enrolling in ARGX-113-2002 from 
Part B must first complete the ED visit 
assessments from ARGX-113-1705 (see Table 
2). Patients who enroll in ARGX-113-2002 
will not return to ARGX-113-1705. 
To provide end of trial 
instruction for patients who 
enroll in study ARGX-113-
2002 
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Section 
Change 
Rationale 
The reason for premature discontinuation from 
the trial must be documented by the 
investigator on the appropriate page of the 
eCRF. 
5.2.1. Treatment Period 
Part A  
Other sections impacted by 
the changed text: 
x Synopsis 
x Table 1 General Schedule 
of Assessments for Part A 
(footnote c) 
x 4.1. Summary of Trial 
Design 
 
If a patient becomes eligible for (re-)treatment 
with efgartigimod per total MG-ADL score 
but cannot complete the entire treatment 
period within the duration of Part A of the trial 
(re-treatment in Part A can start at the latest by 
day 336) the patient can be transitioned to Part 
B after completing the end of Part A (EoA) 
visit. If the patient is not willing or able to 
continue to Part B then he/she should continue 
to the EoA visit. 
changed to 
If a patient becomes eligible for (re-)treatment 
with efgartigimod by meeting the criteria for 
the total MG-ADL score as stated in Section 
4.1, but cannot complete the entire treatment 
period within Part A (ie, after day 336) then 
the patient can be transitioned to Part B after 
completing the EoA visit assessments (Table 
1). These assessments should be completed 
even if the patient is unwilling or unable to 
continue to Part B (see Section 5.1). 
Revised for clarity 
4.3.2. Exclusion Criteria 
Other sections impacted by 
the moved text: 
x Synopsis 
Instruction on contraception requirements 
moved to Appendix 9.   
Contraceptive requirements 
were removed from the 
Exclusion Criterion section for 
logical reasons. 
Appendix 9: Contraceptive 
and Barrier Guidance 
Updated contraception requirements to allow 
for “acceptable” contraception methods per 
CTFG guidelines. 
Guidance on contraception has 
been updated following results 
of nonclinical reproductive 
toxicity studies. 
6. TRIAL TREATMENT 
6.8. Prior Treatments and 
Concomitant Medications 
Other sections impacted by 
the added text: 
x Table 1 General Schedule 
of Assessments for Part A 
(footnote s) 
Added text: 
Any vaccination received within 28 days of 
screening up until 28 days after the final dose 
of the IMP should be recorded in the eCRF 
with the brand name of the vaccine and the 
date of vaccine administration. 
Instructions were added to 
collect vaccination history. 
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Section 
Change 
Rationale 
x Figure 1: ARGX-113-
1705 Trial Design for Part 
A 
x Table 2 General Schedule 
of Assessments for Part B 
(footnote q) 
x Figure 2: ARGX-113-
1705 Trial Design for Part 
B 
7.2.3. Vital Signs, Physical 
Examination, and ECG 
Other sections impacted by 
the added assessment: 
x Table 2 General Schedule 
of Assessments for Part B 
(footnote k) 
x 5.2.2. Trial Period Part B 
and 5.3. Inter Treatment 
Period 
x 5.4. End of Part A, End of 
Study and Early 
Discontinuation Visit 
x 7.2 Safety 
ECG assessment added to Part B 
The ECG assessment was 
added to Part B to comply 
with the DSMB 
recommendation to monitor 
QTcF abnormalities that could 
arise due to the accumulation 
of efgartigimod. 
9.3 Monitoring 
Added text: 
Monitoring details describing strategy (eg, 
risk-based initiatives in operations and quality 
such as Risk Management and Mitigation 
Strategies and Analytical Risk-Based 
Monitoring), methods, responsibilities and 
requirements, including handling of 
noncompliance issues and monitoring 
techniques (central, remote, or on-site 
monitoring) are provided in the monitoring 
plan. 
Clarification 
An additional change was made to allow for testing in patients exhibiting symptoms of COVID-
19 infection. 
Even in countries where COVID-19 safety measures are stopped according to local regulations, 
COVID-19 testing should continue and the results sent to the sponsor for filing. 
 
 
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Section 
Change 
Rationale 
Table 1  General Schedule of 
Assessments for Part A 
and 
Table 2  General Schedule of 
Assessments for Part B 
Bold italics added to Table 1 and Table 2. 
The assessments identified for 
telephone assessment visits are 
highlighted in bold italics in the 
existing Schedule of 
Assessments for Part A in Table 
1 and for Part B in Table 2. 
Footnote added: 
Assessments highlighted by the use of bold 
italics indicate assessments that may be 
carried out as a telephone assessment visit 
under the conditions outlined in 
Appendix 8. 
Appendices 
Appendix 8 added. 
An addendum has been added to 
the study detailing the safety 
measures and changes to be 
implemented in the current 
situation. 
Due to the number of changes, and therefore the size of the tables required to describe all the 
changes made to the protocol, the detailed Summary of Changes tables have been moved to 
Appendix 7. 
For the global amendment of the ARGX-113-1705 protocol from version 2.0 to 3.0 an additional 
part (Part B) has been added to the trial in order to provide the patients with the chance to have 
access to efgartigimod while it is not yet commercially available or available through another 
patient program. This extension to Part A of the trial will be a maximum of 2 years and will also 
enable additional long-term safety and tolerability data to be collected. Below is a comparison of 
the differences between Part A and Part B of the trial: 
Subject 
Part A (1 year) 
Part B (max 2 years) 
Intertreatment period visits 
30 days after the previous visit 
90 days after the previous visit 
Disease severity assessments 
MG-ADL and QMG 
MG-ADL only 
Other assessments 
As per Table 1. 
 
As per Table 2: Fewer assessments 
to reduce burden for the patient:  
No suicidality assessments, ECG, 
anti-AChR/anti-MuSK antibodies 
and total IgG and its subtypes 
Laboratory testing 
Central laboratory for clinical 
laboratory tests (hematology, 
clinical chemistry) 
Local laboratory for clinical 
laboratory tests (hematology, 
clinical chemistry)  
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Subject 
Part A (1 year) 
Part B (max 2 years) 
Standard of care (SoC) 
From 1 week after the last infusion 
of each Treatment Period up to and 
prior to the administration of the 
first infusion of the next Treatment 
Period, a dose reduction in SoC 
consistent with current medical 
practice is allowed 
Change of SoC allowed 
Rescue therapy 
Rescue therapy limited 
Not applicable 
Prohibited medications 
List of prohibited medications 
No prohibited medications 
Safety and disease severity follow-
up period 
Has been removed from the current 
protocol amendment 
Not applicable 
AChR=acetylcholine receptor; ECG=electrocardiogram; IgG=immunoglobulin gamma; MG-ADL=Myasthenia 
Gravis Activities of Daily Living; MuSK=Muscle-Specific Kinase; QMG=Quantitative Myasthenia Gravis score; 
SoC=Standard of Care 
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SYNOPSIS 
Name of Sponsor: 
argenx  
Name of Investigational 
Medicinal Product (IMP): 
Efgartigimod (ARGX-113) 
Name of Active Ingredient: 
A human anti-neonatal crystallizable fragment (Fc) receptor (FcRn) 
immunoglobulin G1 (IgG1) Fc fragment 
Indication: 
Treatment of patients with generalized myasthenia gravis (gMG)  
Title of Trial: 
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 
Protocol No: 
ARGX-113-1705 (ADAPT+) 
Trial Sites: 
This trial is an extension of trial ARGX-113-1704 and will be 
conducted in the sites that participated in the ARGX-113-1704 trial 
Trial Duration: The trial duration will be up to maximum 3 years. The 
trial consists of 2 parts: Part A (1 year) and Part B (up to maximum 
2 years or until efgartigimod becomes commercially available or another 
option to access efgartigimod is available, whichever option comes first). 
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. 
Phase: 3 
Objectives: 
Primary Objective: 
x 
To evaluate the long-term safety and tolerability of efgartigimod in acetylcholine receptor 
antibody (AChR-Ab) seropositive patients 
Secondary Objective: 
x 
To evaluate the long-term safety and tolerability of efgartigimod in the overall population 
(AChR-Ab seropositive and AChR-Ab seronegative patients) 
Tertiary Objectives: 
Part A only: 
x 
To evaluate the disease severity as assessed by total Myasthenia Gravis Activities of Daily 
Living (MG-ADL) score changes in AChR-Ab seropositive patients. 
x 
To evaluate the disease severity as assessed by total MG-ADL score changes in the overall 
population (AChR-Ab seropositive patients and AChR-Ab seronegative patients). 
x 
To evaluate disease severity as assessed by total Quantitative Myasthenia Gravis (QMG) 
score changes in AChR-Ab seropositive patients. 
x 
To evaluate disease severity as assessed by total QMG score changes in the overall 
population (AChR-Ab seropositive patients and AChR-Ab seronegative patients). 
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x 
To evaluate the effect of efgartigimod on pharmacodynamics (PD) (total immunoglobulin 
gamma [IgG], IgG subtypes, autoantibodies [anti-AChR antibodies and anti-muscle-
specific kinase (MuSK) antibodies]). 
Part A and B: 
x 
To evaluate the immunogenicity of efgartigimod. 
Methodology: 
DESCRIPTION 
This is a 3-year (maximum), single-arm, open-label, multicenter, phase 3 follow-on trial of 
ARGX-113-1704 to evaluate the long-term safety and tolerability of efgartigimod in patients with 
gMG. The trial consists of 2 parts: Part A (1 year) and Part B (up to maximum 2 years or until 
efgartigimod becomes commercially available or another option to access efgartigimod is available, 
whichever option comes first). The additional part (Part B) was added to ARGX-113-1705 in order to 
provide the patients with the chance to have access to efgartigimod while it is not yet commercially 
available or available through another patient program. This extension will also enable additional long-
term safety and tolerability data to be collected. 
A variable number of treatment periods consisting of 4 weekly infusions of efgartigimod (10 mg/kg of 
body weight) infused over a period of 3 weeks will be administered to eligible patients on an “as 
needed basis” on top of their standard of care (SoC). The time between treatment periods is based on 
the duration of the treatment effect and may vary from patient to patient and within each patient from 
period to period (patient-tailored approach). 
The first visit of trial ARGX-113-1705 will coincide with the last visit of trial ARGX-113-1704 for 
each patient.  
The study entry baseline (SEB) will be set at the first trial visit, while the baseline of each subsequent 
treatment period (TPnB for Part A or TPEnB for Part B) will be set at visit 1 of each corresponding 
treatment period. 
ROLL-OVER 
At the end of study (EoS) visit of trial ARGX-113-1704, eligible patients will be offered the option to 
roll over into this trial. Patients in need of (re-)treatment in trial ARGX-113-1704 but who cannot 
complete a Treatment Cycle within the time frame of that trial, may immediately roll over to this trial 
to receive treatment with efgartigimod.  
Patients who discontinued early from trial ARGX-113-1704 or discontinued early from randomized 
treatment for rescue or pregnancy reasons or for a serious adverse event (SAE) that is likely to result in 
a life-threatening situation or pose a serious safety risk in that trial will not be offered the option to roll 
over into this trial. 
Patients who discontinued early from randomized treatment for other reasons and patients who had a 
temporary interruption from randomized treatment in trial ARGX-113-1704 may be offered the option 
to roll over into this trial. 
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. 
Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early discontinuation (ED) 
visit assessments specified in Table 2. The previous efgartigimod IV dose must have been received at least 30 
days before entry into ARGX-113-2002. 
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Patients can enroll in ARGX-113-2002 until its recruitment has closed. Patients who enroll in 
ARGX-113-2002 will not return to ARGX-113-1705. 
(RE-)TREATMENT (Part A) 
Each patient will start a (new) treatment period with efgartigimod when all the following criteria apply:  
x 
The patient has completed the previous treatment period (ie, after visit 4) 
x 
The patient has a total MG-ADL score of ≥5 points with more than 50% of the total score 
due to non-ocular symptoms 
x 
The patient has a reduction in the MG-ADL total score of <2 points compared to the score 
at: 
1. The last treatment cycle baseline (TCB) in trial ARGX-113-1704 for the first treatment 
period (TP1) in trial ARGX-113-1705 
2. The last treatment period baseline (TPnB) for all subsequent treatment periods (TPn+1) 
in trial ARGX-113-1705 
However, patients may not receive (re-)treatment with efgartigimod if, at the time of (re-)treatment, 
they have clinical evidence of bacterial, viral or fungal disease, or any other significant disease which 
could confound the results of the trial or put patients at undue risk. Patients who are in need of an 
additional treatment but who are not eligible to receive (re-)treatment for reasons listed here will 
remain in the trial to receive appropriate alternative MG treatment (see Appendix 5 and Appendix 6). 
Patients who show a treatment failure to efgartigimod for 3 consecutive treatment periods will be 
discontinued from the trial. Treatment failure means the absence of a decrease of at least 2 points in 
total MG-ADL score compared to the corresponding TPnB in at least 50% of the assessments (ie, 
TPnV2, TPnV3, TPnV4 and the first posttreatment period visit).  
If a patient becomes eligible for (re-)treatment with efgartigimod by meeting the criteria for the total 
MG-ADL score as stated in Section 4.1, but cannot complete the entire treatment period during Part A 
(ie, after day 336) then the patient can be transitioned to Part B after completing the end of Part A 
(EoA) visit assessments (Table 1). These assessments should be completed even if the patient is 
unwilling or unable to continue to Part B (see Section 5.1). 
The transition to Part B can be either at ITPE0V1 or TPE1V1, depending on the patient’s status 
regarding the need for (re-)treatment upon transition from Part A. The first visit in Part B will always 
coincide with the EoA visit in Part A. The assessments done for the last visit in Part A should not be 
repeated in Part B. 
(RE-)TREATMENT (Part B) 
If the patient feels that his/her condition has deteriorated, then the investigator may start a new 
treatment period at an intertreatment period (ITPE) visit or the patient may contact the investigator to 
attend an unscheduled visit. 
A patient can start the next treatment period and receive efgartigimod if all of the following criteria are 
met:  
x 
The patient has completed the previous treatment period (ie, after visit 4)* 
x 
The investigator determines that the patient will benefit from re-treatment 
x 
There is at least 1 calendar month (minimum 4 weeks) between treatment periods (ie, between 
TPEnV4 and TPEn+1V1) 
*A patient who has had a temporary interruption of trial treatment in Part A may also continue into Part 
B of the trial and receive (re-)treatment if the conditions in Section 4.4.1 are met. 
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However, patients may not receive (re-)treatment with efgartigimod if, at the time of (re-)treatment, 
they have clinical evidence of bacterial, viral or fungal disease, or any other significant disease which 
could confound the results of the trial or put patients at undue risk. 
If a patient becomes eligible for (re-)treatment with efgartigimod but cannot complete the entire 
treatment period within the duration of the trial, the patient should continue to the EoS visit. 
If the investigator considers that the patient will not have a clinical benefit from (re-)treatment then the 
patient cannot start a new treatment period. The patient should then continue to the EoS visit. 
STANDARD OF CARE (SoC) 
In Part A: 
Permitted SoC for MG treatment under this protocol include NSIDs (eg, azathioprine, methotrexate, 
cyclosporine, tacrolimus, mycophenolate mofetil, and cyclophosphamide), steroids, as well as 
acetylcholinesterase (AChE) inhibitors. 
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment of the 
SoC dose and/or frequency) is not allowed: 
x 
From trial entry until 1 week after the last infusion of the first treatment period. 
x 
From the first infusion until 1 week after the last infusion of each subsequent treatment 
period. 
From 1 week after the last infusion of each treatment period up to and prior to the administration of the 
first infusion of the next treatment period, a dose reduction in SoC consistent with current medical 
practice is allowed. 
In case these medications are taken for another indication than MG, same conditions apply. 
Administration of AChE inhibitors must be halted for at least 12 hours prior to performing the QMG 
assessment. Following this requirement, this possible temporary change in dosing regimen of AChE 
inhibitors will not be considered as a change in SoC. 
In Part B: 
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment of the 
SoC dose and/or frequency) is allowed, without restrictions, following current medical practice. 
Plasma exchange (PLEX), intravenous immunoglobulin (IVIg), immunoadsorption or use of a new 
type of corticosteroid or an increased dose of the current corticosteroids used as stand-alone therapy or 
in combination is also allowed in Part B. 
TIME BETWEEN TREATMENT PERIODS 
At the end of each treatment period, patients will enter a variable intertreatment period during which 
they will be treated with their SoC only. The length of the intertreatment period may vary from patient 
to patient and for each patient from period to period (patient-tailored approach). For Part A, the visit 
frequency in the intertreatment period is every 30 days (± 2 days) after the previous visit. For Part B, 
the visit frequency in the intertreatment period is every 90 days (± 7 days) after the previous visit. If an 
inter-treatment period (ITP) visit for Part A is scheduled within 14 days of the EoA visit, then the EoA 
visit should be performed instead. 
RESCUE THERAPY (Part A only) 
Rescue therapy will be limited to PLEX, IVIg, immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current corticosteroids used as stand-alone therapy or in 
combination. 
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Rescue therapy is permitted for patients experiencing protocol-defined MG clinical deterioration AND 
if in addition the treating physician believes that the patient’s health is in jeopardy if rescue therapy is 
not given. An MG clinical deterioration permitting rescue therapy to be given is defined as a patient 
experiencing at least 1 of the following: (1) new or worsening of respiratory / bulbar symptoms or (2) 
at least 2-point increase of individual non-ocular MG-ADL items. Whenever possible, prior to giving 
rescue therapy to a patient, the Medical Director at the sponsor and the Medical Monitor at the 
sponsor’s designated Contract Research Organization (CRO) should be informed. 
In situations where the treatments as listed above are given under the protocol-defined rescue criteria, 
patients will be discontinued early from the trial. 
EARLY DISCONTINUATION 
For patients who discontinue early from the trial, the assessments will depend on the visit at which it 
was decided that the patient had to discontinue (see Section 5.4, Figure 1, and Figure 2). 
Patients who discontinue early from the trial within a treatment period should perform the planned 
assessments of the corresponding treatment period visit. These patients will not receive any further 
administration of efgartigimod during the trial and will return for the ED visit 1 month (30 ± 2 days) 
after the last dose administration. An unscheduled visit can be organized if deemed necessary by the 
investigator. 
Patients who discontinue early from the trial between the last visit of a treatment period (TPnV4 or 
TPEnV4) and the next intertreatment period visit (ITPnVn or ITPEnVn) should perform the ED 
assessments 1 month (30 ± 2 days) after the last dose administration. 
Patients who discontinue early from the trial at the ITP (Part A) or ITPE (Part B) visit should perform 
the ED assessments, instead of the ITPnVn (Part A) or ITPEnVn (Part B) assessments.  
Patients who discontinue early from the trial after the ITP (Part A) or ITPE (Part B) visit should 
perform the ED assessments. 
Any patient prematurely discontinuing the trial during Part A should perform the EoA/ED assessments 
according to the General Schedule of Assessments for Part A (Table 1). Any patient prematurely 
discontinuing the trial during Part B should perform the EoS/ED assessments according to the General 
Schedule of Assessments for Part B (Table 2). 
Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early discontinuation (ED) 
visit assessments specified in Table 2. The previous efgartigimod IV dose must have been received at least 30 
days before entry into ARGX-113-2002. Patients who enroll in ARGX-113-2002 will not return to ARGX-
113-1705. 
TEMPORARY INTERRUPTION FROM TRIAL TREATMENT 
A patient who does not need to be discontinued early from the trial might still have a temporary 
interruption from trial treatment which is defined as a discontinuation only from the current treatment 
period. Therefore, these patients might still be eligible for further additional treatments with 
efgartigimod within this trial. 
Patients for whom treatment is interrupted will have to complete the current treatment period and will 
continue the trial as per the General Schedule of Assessments for Part A (Table 1) or for Part B 
(Table 2) but without drug administration. A patient who has had a temporary interruption of trial 
treatment in Part A may also continue into Part B of the trial and receive (re-)treatment if the 
conditions mentioned above are met. 
Planned Number of Patients: 
The maximum number of patients in this trial will be the number of 
patients who participated in trial ARGX-113-1704. 
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Criteria for Inclusion and 
Exclusion: 
Inclusion Criteria: 
1. Patients with the ability to understand the requirements of 
the trial, provide written informed consent, and can comply 
with the trial protocol procedures. 
2. Patients who participated in trial ARGX-113-1704 and are 
eligible for roll over, ie: 
x 
Patients who reached EoS at day 182 in trial ARGX-
113-1704. 
x 
Patients who need (re-)treatment in trial ARGX-113-
1704 but cannot complete a Treatment Cycle within the 
time frame of that trial may immediately roll over into 
this trial to receive treatment with efgartigimod. 
x 
Patients who discontinued early from randomized 
treatment for other reasons than pregnancy, rescue 
therapy or an (S)AE in trial ARGX-113-1704 may be 
offered the option to roll over into this trial. 
x 
Patients who had a temporary interruption from 
randomized treatment in trial ARGX-113-1704 may be 
offered the option to roll over into this trial. 
3. Patients are required to be on a stable dose of their MG 
treatment (SoC) prior to SEB. The SoC is limited to 
acetylcholinesterase (AChE) inhibitors, steroids and non-
steroidal immunosuppressive drugs (NSIDs) 
(eg, azathioprine, methotrexate, cyclosporine, tacrolimus, 
mycophenolate mofetil, and cyclophosphamide). 
Note: AChE inhibitors must be withheld for at least 
12 hours consistent with the revised manual for the QMG 
test as recommended by the Myasthenia Gravis Foundation 
of America (MGFA), before the QMG assessment. 
 
Exclusion Criteria: 
1. Patients who discontinued early from trial ARGX-113-1704 
or patients who discontinued early from randomized 
treatment for rescue or pregnancy reasons or an SAE that is 
likely to result in a life-threatening situation or pose a 
serious safety risk. 
2. Pregnant and lactating women, and those intending to 
become pregnant during the trial or within 90 days after the 
last dosing. Women of childbearing potential 
(DEFINITION OF TERMS) should have a negative urine 
pregnancy test at SEB. The contraceptive requirements for 
women of childbearing potential are described in Error! 
Not a valid result for table.. 
3. Male patients who are sexually active and do not intend to 
use effective methods of contraception (as mentioned 
above) during the trial or within 90 days after the last 
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dosing or male patients who plan to donate sperm during 
the trial or within 90 days after the last dosing. The 
contraceptive requirements for male patients are described 
in Error! Not a valid result for table.. 
4. Patients with known hepatitis B virus (HBV), hepatitis C 
virus (HCV) or human immunodeficiency virus (HIV) 
seropositivity. 
5. Patients with known autoimmune disease other than MG 
(for example autoimmune thyroiditis, rheumatoid arthritis, 
…) that would interfere with an accurate assessment of 
clinical symptoms. 
6. Patients with clinical evidence of other significant disease 
or patients who underwent a recent major surgery, which 
could confound the results of the trial or put the patient at 
undue risk. Patients with renal/hepatic function impairment 
can be included. 
7. Patients with known medical history of hypersensitivity to 
any of the ingredients of efgartigimod. 
Test Product, Dose, and Mode 
of Administration: 
In this trial, the test product is efgartigimod (ARGX-113), which is 
a human anti-FcRn IgG1 Fc fragment. In patients who need (re)-
treatment, a dose of 10 mg/kg of body weight of efgartigimod will 
be administered at visits 1, 2, 3, and 4 of each treatment period as an 
intravenous (IV) infusion over a period of 1 hour. The total dose per 
efgartigimod infusion is capped at 1200 mg for patients with body 
weight ≥120 kg. 
Criteria for Evaluation: 
Primary Endpoint: 
x 
Incidence and severity of AEs, SAEs, vital signs, electrocardiogram (ECG) and laboratory 
assessments over the duration of the trial in AChR-Ab seropositive patients. 
Secondary Endpoint: 
x 
Incidence and severity of AEs, SAEs, vital signs, ECG and laboratory assessments over the 
duration of the trial in the overall population (AChR-Ab seropositive patients and AChR-
Ab seronegative patients). 
Tertiary Endpoints: 
Part A only: 
x 
Total MG-ADL score changes compared to the treatment period baseline of the first cycle 
(TP1B) and the corresponding TPnB in AChR-Ab seropositive patients. 
x 
Total MG-ADL score changes compared to TP1B and the corresponding TPnB in the 
overall population (AChR-Ab seropositive and AChR-Ab seronegative patients). 
x 
Total QMG score changes compared to TP1B and the corresponding TPnB in AChR-Ab 
seropositive patients. 
x 
Total QMG score changes compared to TP1B and the corresponding TPnB in the overall 
population (AChR-Ab seropositive and AChR-Ab seronegative patients). 
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x 
Percentage decrease (compared to TP1B and the corresponding TPnB) of total IgG level 
and IgG subtypes in efgartigimod (re-)treated patients. 
x 
Percentage decrease (compared to TP1B and the corresponding TPnB) of autoantibodies 
(anti-AChR antibodies and anti-MuSK antibodies) in efgartigimod (re-)treated patients. 
Part A and B: 
x 
Incidence and prevalence of anti-drug antibodies (ADA) to efgartigimod. 
Statistical Methods and Plan:  
A Statistical Analysis Plan detailing all statistical methods and analyses will be issued before any 
database lock. A summary of the plan is described below. 
All endpoints will be summarized in all enrolled patients by means of descriptive statistics. 
Summary statistics will be provided for the continuous endpoints (eg, total MG-ADL score, total QMG 
score, levels of total IgG and subtypes, anti-AChR/anti-MuSK antibodies, laboratory values, vital 
signs, ECG) in terms of absolute values, changes from TP1B or changes from TPnB, by cycle and 
available time points. 
Frequency tables will be made for all binary variables, ie, AEs and ADA by cycle and overall.  
 
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after the last dose administration. An unscheduled visit can be organized if deemed necessary by the investigator. Patients who discontinue early from the trial 
between the last visit of a treatment period (TPnV4) and the next intertreatment period visit (ITPnVn) should perform the ED assessments 1 month (30 ± 2 
days) after the last dose administration. Patients who discontinue early from the trial at the ITP visit should perform the ED assessments instead of the ITPnVn 
assessments. Patients who discontinue from the trial after the ITP visit should perform the ED assessments. 
e An unscheduled (UNS) visit can occur at the request of the patient or the investigator. During the UNS visit, additional assessments as indicated in the SoA can 
be performed at the discretion of the investigator, depending on the reason for the UNS visit. 
f No trial-related assessment is to be carried out before the patient has signed the informed consent form (ICF). 
g Assessments of disease severity should be completed predose on dosing days and before any other trial-specific assessment, except for obtaining informed 
consent at SEB and the weight assessment, if applicable. The MG-ADL scale should be administered before the QMG scale. Acetylcholinesterase inhibitors 
must be halted for at least 12 hours before the QMG assessment (consistent with the revised manual for the QMG test as recommended by the Myasthenia 
Gravis Foundation of America [MGFA]). 
h Suicidal ideation and behavior will be assessed predose on dosing days via a targeted question based on the Patient Health Questionnaire item 9 (PHQ-9). 
i The physical examination will be performed predose on dosing days. See Section 7.2.3 for an overview of the different assessments. 
j Weight will be measured at SEB, at the EoA/ED visit, and when there is an obvious weight change compared to the last weight assessment. Height will be 
measured at SEB. 
k Vital signs (supine blood pressure, heart rate, body temperature) will be performed predose on dosing days. It is recommended that the method used to measure 
body temperature at SEB is maintained throughout the trial for each patient. 
l ECG will be performed predose on dosing days. 
m Samples for clinical laboratory tests (hematology, clinical chemistry) will be collected predose on dosing days (see Appendix 3). Patients need to have fasted at 
least 8 hours prior to each sampling. 
n Urine samples will be collected predose on dosing days (see Appendix 3). 
o A urine pregnancy test will be performed predose on dosing days on the urine samples taken for urinalysis (only for women of childbearing potential, see 
DEFINITION OF TERMS). 
p Samples for pharmacodynamic (PD) biomarkers will be collected predose on dosing days (see Appendix 3). Anti-AChR antibodies will be measured in AChR-
Ab seropositive patients only. Anti-MuSK antibodies will be measured in MuSK-Ab seropositive patients only. Information on the AChR/MuSK-Ab serotype 
(seronegative or seropositive) is available from trial ARGX-113-1704. 
q Samples for anti-drug antibodies (ADAs) will be collected predose on dosing days. 
r Efgartigimod will be administered as an intravenous (IV) infusion over a period of 1 hour at visits 1, 2, 3, and 4 of each treatment period. Patients will remain 
at the site for at least 1 hour following the end of the infusion for safety monitoring based on the patient’s clinical status. At TPnV1, the conditions for (re-) 
treatment will be checked before administration of efgartigimod. 
s Clinically relevant prior treatment will only be recorded at SEB. All available vaccination history will be recorded as part of the participant’s prior medication 
for vaccinations received in the past or concomitant medication for vaccinations received during the trial. For vaccines where multiple doses or boosters are 
received, only the most recent one must be recorded. 
*Assessments highlighted by use of bold italics indicate assessments that may be carried out as a telephone assessment visit under the conditions outlined in 
Appendix 8. 
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d For patients who discontinue early from the trial, the assessments will depend on the visit at which it was decided that the patient had to discontinue (see 
Section 5.4). Patients who discontinue early from the trial within a treatment period should perform the planned assessments of the corresponding treatment 
period visit. These patients will not receive any further administration of efgartigimod during the trial and return for the ED visit 1 month (30 ±2 days) after the 
last dose administration. An unscheduled visit can be organized if deemed necessary by the investigator. Patients who discontinue early from the trial between 
the last visit of a treatment period (TPEnV4) and the next intertreatment period visit (ITPEnVn) should perform the ED assessments 1 month (30 ±2 days) after 
the last dose administration. Patients who discontinue early from the trial at the ITPE visit should perform the ED assessments instead of the ITPEnVn 
assessments. Patients who discontinue prematurely from the trial after the ITPE visit should perform the ED assessments. 
e Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early discontinuation (ED) visit assessments. The previous efgartigimod IV 
dose must have been received at least 30 days before entry into ARGX-113-2002. 
f An unscheduled (UNS) visit can occur at the request of the patient or the investigator. During the UNS visit, additional assessments as indicated in the SoA can 
be performed at the investigator's discretion, depending on the reason for the UNS visit. 
g The transition to Part B can be either ITPE0Vn or TPE1V1, depending on the patient status regarding the need for (re-)treatment upon transition from Part A. 
The first visit in Part B will always coincide with the EoA visit in Part A. The assessments done for the last visit in Part A should not be repeated in Part B. 
h Assessments of disease severity should be completed predose on dosing days and before any other trial-specific assessment, except weight, if applicable. 
i Weight will be measured at visit 1, the EoS/ED visit, and any visit when a weight change is obvious compared to the last weight measurement. 
j Vital signs (supine blood pressure, heart rate, body temperature) will be performed predose on dosing days. It is recommended that the method used to measure 
body temperature is maintained throughout the trial for each patient. 
k A 12-lead ECG will be recorded locally. The assessments on heart rate, PR, QT, and QRS intervals will be read centrally. 
l Samples for clinical laboratory tests (hematology, clinical chemistry) will be collected predose on dosing days, if applicable (see Appendix 3). 
m Urine samples will be collected predose on dosing days (see Appendix 3). 
n If a urine pregnancy test is carried out on a dosing day, then it should be performed predose (only for women of childbearing potential, see DEFINITION OF 
TERMS). 
o Samples for anti-drug antibodies (ADAs) will be collected predose on dosing days (if applicable) and collected only in the case of early discontinuation and not 
at the EoS visit.  
p Efgartigimod will be administered as an intravenous (IV) infusion over a period of 1 hour at visits 1, 2, 3, and 4 of each treatment period. Patients will remain 
at the site for at least 1 hour following the end of the infusion for safety monitoring based on the patient’s clinical status. At TPEnV1, the conditions for (re-) 
treatment will be checked before administration of efgartigimod. 
q All available vaccination history will be recorded as part of the participant’s prior medication for vaccinations received in the past or concomitant medication 
for vaccinations received during the trial. For vaccines where multiple doses or boosters are received, only the most recent one must be recorded. 
*Assessments highlighted by use of bold italics indicate assessments that may be carried out as a telephone assessment visit under the conditions outlined in 
Appendix 8. 
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TABLE OF CONTENTS 
TITLE PAGE ...................................................................................................................................1 
SIGNATURE OF SPONSOR ..........................................................................................................3 
SIGNATURE OF INVESTIGATOR ..............................................................................................4 
DOCUMENT HISTORY.................................................................................................................5 
SUMMARY OF CHANGES ...........................................................................................................5 
SYNOPSIS 11 
LIST OF ABBREVIATIONS ........................................................................................................30 
DEFINITION OF TERMS ............................................................................................................34 
1. 
INTRODUCTION ......................................................................................................37 
1.1. 
Background Information .............................................................................................37 
1.2. 
Investigational Medicinal Product ..............................................................................38 
1.3. 
Standard of Care and Rationale for the Use of Efgartigimod .....................................39 
1.4. 
Benefit-Risk Assessment ............................................................................................40 
2. 
TRIAL OBJECTIVES ................................................................................................43 
2.1. 
Primary Objective .......................................................................................................43 
2.2. 
Secondary Objective ...................................................................................................43 
2.3. 
Tertiary Objectives .....................................................................................................43 
3. 
TRIAL ENDPOINTS .................................................................................................44 
3.1. 
Primary Endpoint ........................................................................................................44 
3.2. 
Secondary Endpoint ....................................................................................................44 
3.3. 
Tertiary Endpoints ......................................................................................................44 
4. 
INVESTIGATIONAL PLAN .....................................................................................45 
4.1. 
Summary of Trial Design ...........................................................................................45 
4.2. 
Discussion of Trial Design .........................................................................................49 
4.3. 
Selection of Trial Population ......................................................................................51 
4.3.1. 
Inclusion Criteria ........................................................................................................51 
4.3.2. 
Exclusion Criteria .......................................................................................................51 
4.4. 
Early Discontinuation .................................................................................................52 
4.4.1. 
Temporary Interruption From Trial Treatment ...........................................................54 
4.4.2. 
Missed Doses ..............................................................................................................54 
4.5. 
Protocol Deviations ....................................................................................................54 
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4.6. 
Early Termination of Trial or Site ..............................................................................54 
4.7. 
End of Trial Definition ...............................................................................................54 
5. 
TRIAL PROCEDURES..............................................................................................55 
5.1. 
Informed Consent and Roll-Over Visit .......................................................................55 
5.2. 
Treatment Period ........................................................................................................56 
5.2.1. 
Treatment Period Part A .............................................................................................56 
5.2.2. 
Treatment Period Part B .............................................................................................58 
5.3. 
Intertreatment Period ..................................................................................................59 
5.4. 
End of Part A, End of Study, and Early Discontinuation Visit ..................................60 
5.5. 
Unscheduled Visit .......................................................................................................61 
6. 
TRIAL TREATMENT ...............................................................................................62 
6.1. 
Treatment Administered .............................................................................................62 
6.2. 
Identity of Investigational Medicinal Product ............................................................62 
6.3. 
Packaging and Labeling ..............................................................................................62 
6.4. 
Storage of Investigational Medicinal Product ............................................................62 
6.5. 
Method of Assigning Patients to Treatment Group ....................................................63 
6.6. 
Timing of Dose for Each Patient ................................................................................63 
6.7. 
Blinding ......................................................................................................................63 
6.8. 
Prior Treatments and Concomitant Medications ........................................................63 
6.8.1. 
Prohibited Medications During the Trial ....................................................................63 
6.8.2. 
Rescue Therapy (Part A only) ....................................................................................64 
6.9. 
Medical Care of Patients After End of Study .............................................................64 
6.10. 
Treatment Compliance ................................................................................................64 
6.11. 
Handling Missed Doses of Investigational Medicinal Product ..................................65 
6.12. 
Accountability of Investigational Medicinal Product .................................................65 
6.13. 
Storage of Blood Samples in the Trial ........................................................................65 
7. 
TRIAL ASSESSMENTS ............................................................................................66 
7.1. 
Monitoring of Disease Severity ..................................................................................66 
7.1.1. 
Myasthenia Gravis Activities of Daily Living ............................................................66 
7.1.2. 
Quantitative Myasthenia Gravis .................................................................................66 
7.2. 
Safety ..........................................................................................................................66 
7.2.1. 
Adverse Events ...........................................................................................................67 
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7.2.1.1. 
Adverse Events of Special Interest .............................................................................69 
7.2.1.2. 
Reporting of Adverse Events and Serious Adverse Events ........................................69 
7.2.1.3. 
Reporting of Serious Adverse Events to Regulatory Authorities and 
Investigators ................................................................................................................70 
7.2.1.4. 
Follow-up of Adverse Events and Serious Adverse Events .......................................71 
7.2.1.5. 
Reporting and Follow-up Requirements for Pregnancies ...........................................71 
7.2.2. 
Clinical Laboratory Evaluations .................................................................................72 
7.2.3. 
Vital Signs, Physical Examination, and ECG .............................................................73 
7.2.4. 
Suicidality Assessment ...............................................................................................73 
7.2.5. 
Medical and Surgical History .....................................................................................74 
7.2.6. 
Data Safety Monitoring Board (DSMB) .....................................................................74 
7.2.7. 
Visit Reminder/Subject ID Card .................................................................................74 
7.3. 
Pharmacodynamics .....................................................................................................74 
7.4. 
Anti-Drug Antibodies .................................................................................................75 
8. 
STATISTICS ..............................................................................................................76 
8.1. 
Determination of Sample Size ....................................................................................76 
8.2. 
Analysis Populations ..................................................................................................76 
8.3. 
Patient Disposition, Characteristics and Concomitant Medication ............................76 
8.4. 
Statistical Methods ......................................................................................................76 
8.4.1. 
Primary and Secondary Endpoint Analyses ...............................................................76 
8.4.2. 
Tertiary Endpoint Analyses ........................................................................................77 
8.5. 
Interim Analyses .........................................................................................................77 
9. 
QUALITY CONTROL AND QUALITY ASSURANCE .........................................78 
9.1. 
Investigator’s Responsibility ......................................................................................78 
9.2. 
Quality Control of Data ..............................................................................................78 
9.3. 
Monitoring ..................................................................................................................79 
9.4. 
Data Management .......................................................................................................79 
9.5. 
Quality Assurance Audit .............................................................................................80 
10. 
ETHICS ......................................................................................................................81 
10.1. 
Institutional Review Board or Independent Ethics Committee ..................................81 
10.2. 
Ethical Conduct of the Trial .......................................................................................81 
10.3. 
Patient Information and Informed Consent ................................................................81 
10.4. 
Patient Data Protection ...............................................................................................82 
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11. 
TRIAL ADMINISTRATION .....................................................................................83 
11.1. 
Data Handling and Record Keeping ...........................................................................83 
11.2. 
Direct Access to Source Data/Documents ..................................................................83 
11.3. 
Investigator Information .............................................................................................84 
11.3.1. 
Investigator Obligations ..............................................................................................84 
11.3.2. 
Protocol Signatures .....................................................................................................84 
11.3.3. 
Publication Policy .......................................................................................................84 
11.3.4. 
Financing and Insurance .............................................................................................84 
12. 
REFERENCES ...........................................................................................................85 
13. 
APPENDICES ............................................................................................................87 
APPENDIX 1: Myasthenia Gravis Activities of Daily Living ......................................................87 
APPENDIX 2: Quantitative Myasthenia Gravis Score ...............................................................88 
APPENDIX 3: Laboratory Evaluations ......................................................................................89 
APPENDIX 4: Administrative Structure ....................................................................................90 
APPENDIX 5: Decision Tree for Re-Treatment in Part A (Part 1) ............................................92 
APPENDIX 6: Decision Tree for Re-Treatment in Part A and Part B (Part 2) ..........................93 
APPENDIX 7: Summary of Changes From Prior Amendments ................................................94 
Protocol Version 3.1 compared to Protocol Version 3.2 ...............................................................94 
Protocol Version 3.0 compared to Protocol Version 3.1 ...............................................................95 
Protocol Version 2.0 compared to Protocol Version 3.0 ...............................................................96 
Protocol Version 1.0 compared to Protocol Version 2.0 .............................................................127 
APPENDIX 8: Temporary Changes to Study Procedures in ARGX-113-1705 Related 
to the COVID-19 Pandemic ......................................................................................135 
APPENDIX 9: Contraceptive and Barrier Guidance ................................................................135 
 
 
 
 
 
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LIST OF TABLES 
Table 1 
General Schedule of Assessments for Part A .............................................................19 
Table 2 
General Schedule of Assessments for Part B .............................................................23 
 
 
LIST OF FIGURES 
Figure 1: 
ARGX-113-1705 Trial Design for Part A ..................................................................22 
Figure 2: 
ARGX-113-1705 Trial Design for Part B ..................................................................25 
 
LIST OF ABBREVIATIONS 
ABDEG™ 
antibody that enhances IgG degradation 
AChE 
acetylcholinesterase 
AChR 
acetylcholine receptor 
ADA 
anti-drug antibodies 
ADL 
activities of daily living 
ADR 
adverse drug reaction 
AE 
adverse event 
CIOMS 
Council for International Organizations of Medical Sciences 
CRO 
contract research organization 
CTCAE 
Common Terminology Criteria for Adverse Events 
CTR 
clinical trial report 
DSMB 
Data Safety Monitoring Board 
ECG 
electrocardiogram 
eCRF 
electronic case report form 
ED 
early discontinuation 
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EDC 
electronic data capture 
EoA 
end of Part A of the study 
EoS 
end of study 
Fc 
crystallizable fragment 
FcRn 
neonatal Fc receptor 
FDA 
Food and Drug Administration 
FSH 
follicle-stimulating hormone 
GCP 
good clinical practice 
gMG 
generalized myasthenia gravis 
HBV 
hepatitis B virus 
HCV 
hepatitis C virus 
HEL-ABDEG™ 
full-length monoclonal antibody analog of ABDEG™ 
HIV 
human immunodeficiency virus 
IB 
investigator’s Brochure 
ICF 
informed consent form 
ICH 
International Council for Harmonisation 
IEC 
Independent Ethics Committee 
IgG 
immunoglobulin gamma 
IMP 
investigational medicinal product 
IND 
investigational new drug 
IRB 
Institutional Review Board 
ITPV 
intertreatment period visit in Part A 
ITPEV 
intertreatment period visit in Part B 
IV 
intravenous 
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IVIg 
intravenous immunoglobulin 
LRP4 
lipoprotein receptor-related protein 4 
MG 
myasthenia gravis 
MG-ADL 
Myasthenia Gravis Activities of Daily Living 
MGFA 
Myasthenia Gravis Foundation of America 
MuSK 
muscle-specific kinase 
NCI 
National Cancer Institute 
NSID 
non-steroidal immunosuppressive drug 
PD 
pharmacodynamic(s) 
PHQ-9 
Patient Health Questionnaire item 9 
PLEX 
plasma exchange 
PK 
pharmacokinetic(s) 
QMG 
Quantitative Myasthenia Gravis 
SAE 
serious adverse event 
SEB 
study entry baseline 
SoC 
standard of care 
SOP 
standard operating procedures 
SUSAR 
suspected unexpected serious adverse reaction 
TCB 
treatment cycle baseline 
TEAE 
treatment-emergent adverse event 
TPB 
treatment period baseline 
TPE 
treatment period in Part B 
TPnB 
subsequent treatment period baseline in Part A 
TPEnB 
subsequent treatment period baseline in Part B 
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UNS 
unscheduled visit 
US 
United States 
WBC 
white blood count 
WHO(-DD) 
World Health Organization (Drug Dictionary) 
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DEFINITION OF TERMS 
Childbearing potential: 
Women of childbearing potential are defined as all female 
participants unless they are postmenopausal (defined by 
continuous amenorrhea) for at least 2 years with a follicle-
stimulating hormone (FSH) >40 IU/L or are surgically sterile 
(ie, who had a hysterectomy, bilateral oophorectomy, or have 
current documented tubal ligation or any other permanent 
female sterilization procedure).  
Council for International 
Organizations of Medical 
Sciences (CIOMS): 
The Council for International Organizations of Medical 
Sciences (CIOMS) is an international, non-governmental, non-
profit organization established jointly by World Health 
Organization (WHO) and UNESCO in 1949. They provide a 
set of ethical principles regarding human experimentations, 
including International Reporting of Adverse Drug Reactions 
and International Reporting of Periodic Drug-Safety Update 
Summaries. 
The CIOMS form provides a standardized format for the 
reporting of suspected adverse reactions to any particular 
medical product and is the acceptable and widely used format 
for reporting suspect adverse drug reaction (ADR)/suspected 
unexpected serious adverse reaction (SUSAR) in clinical trials. 
Contract Research 
Organization (CRO): 
A person, or a group of persons (commercial, academic, or 
other), who as an independent contractor with argenx BVBA, 
assume(s) 1 or more obligations of argenx BVBA, 
eg, development of a protocol, selection and/or monitoring of 
investigators, evaluation of reports, preparation of materials to 
be submitted to Health Authorities. 
Cycle 
A cycle is a treatment period plus the intertreatment period. 
Database Lock: 
An action taken to prevent further changes to a trial database. 
A database is locked after review, query resolution, data 
cleaning and determination that it is ready for analysis. 
Data Safety Monitoring 
Board (DSMB): 
Independent group of experts that advises and whose 
responsibilities are to periodically review and evaluate the 
accumulated trial data for participant safety, trial conduct and 
progress and, when appropriate, efficacy and to make 
recommendation to the sponsor concerning the continuation, 
modification or termination of the trial. 
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Eligible: 
Qualified for roll-over into the trial based upon strict adherence 
to inclusion/exclusion criteria. 
Good Clinical Practice 
(GCP): 
A standard for the design, conduct, performance, monitoring, 
auditing, recording, analyses, and reporting of clinical trials 
that provides assurance that the data and reported results are 
credible and accurate, and that the rights, integrity, and 
confidentiality of trial subjects are protected (ICH E6). 
Institutional Review Board 
(IRB)/Independent Ethics 
Committee (IEC): 
An independent body (a review board or a committee, 
institutional, regional, national, or supranational), constituted 
of medical professionals and non-medical members, whose 
responsibility it is to ensure the protection of the rights, safety 
and well-being of human subjects involved in a trial and to 
provide public assurance of that protection, by, among other 
things, reviewing and approving / providing favorable opinion 
on, the trial protocol, the suitability of the investigator(s), 
facilities, and the methods and material to be used in obtaining 
and documenting informed consent of the trial subjects. 
Informed Consent/ 
Informed Consent Form 
(ICF): 
A process by which a clinical investigation participant 
voluntarily confirms his or her willingness to participate in a 
particular clinical trial, after having been informed of all 
aspects of the trial that are relevant to the participant’s decision 
to participate. Informed consent is documented by means of a 
dated and signed informed consent form (ICF). 
International Conference 
on Harmonisation (ICH): 
The International Conference on Harmonisation of Technical 
Requirements for Registration of Pharmaceuticals for Human 
Use (ICH) is a project that brings together the regulatory 
authorities of Europe, Japan and the United States and experts 
from the pharmaceutical industry in the 3 regions to discuss 
scientific and technical aspects of pharmaceutical product 
registration. 
Investigational Medicinal 
Product: 
A pharmaceutical form of an active ingredient being tested or 
used as a reference in a clinical trial, including a product with a 
marketing authorization when used in a way different from the 
approved form, or when used for an unapproved indication, or 
when used to gain further information about an approved use.  
Protocol amendment: 
A written description of a change(s) to or formal clarification 
of a protocol. 
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Treatment: 
Term used throughout the clinical trial to denote a set of 
investigational product(s) or marketed product(s) intended to 
be administered to a subject. 
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1. 
INTRODUCTION 
1.1. 
Background Information 
Myasthenia gravis (MG) is an autoimmune disorder characterized in most cases by T-cell and 
antibody responses to neuromuscular junction proteins such as skeletal muscle nicotinic 
acetylcholine receptor (AChR). Antibodies against epitopes of the AChR of the neuromuscular 
junction cause failure of neuromuscular transmission, resulting in the characteristic fatigue and 
weakness associated with this severe disorder. The muscle weakness fluctuates with activity, and 
periods of rest offer only a temporary reprieve.1  
Autoimmune MG has a reported worldwide prevalence of 40-180 per million people and an 
annual incidence of 4-12 per million people. Overall, MG incidence and prevalence shows little 
geographic variation.2  
Autoimmune MG is characterized by the presence of antibodies against several components of 
the neuromuscular junctions. The most common antibody found in autoimmune MG is directed 
against post-synaptic AChRs. Anti-AChR antibodies are present in approximately 80% of all 
autoimmune MG patients. Less frequent autoantibodies found in autoimmune MG include the 
anti-muscle-specific kinase (MuSK) antibody (4% of the cases), and the anti-lipoprotein 
receptor-related protein 4 (LRP4) antibody (2% of the cases) directed against LRP4. All these 
autoantibodies belong to the immunoglobulin gamma (IgG) class.2,3  
In approximately 5% to 20% of the MG patients, no serum antibodies against neuromuscular 
junction proteins can be detected.4,5  Although in some seronegative MG patients the disease 
may not be mediated by antibodies, in other cases the (apparent) absence of specific 
autoantibodies in patients may be due to insufficient sensitivity of the assay. Indeed, one-third of 
MG patients, who are seronegative on standard testing, are seropositive on cell-based testing. 
The seronegative group probably includes some patients with anti-AChR, -MuSK or -LRP4 
antibodies that are not detected because of insufficient test sensitivity.3  
The treatment of MG is based on a variety of medications and medical procedures used either 
alone or in combination (see Section 1.3). 
Given the pathogenic role of autoantibodies in MG, a possible novel therapeutic approach to this 
disease may include the use of drugs that lower the level of pathogenic autoantibodies rapidly 
and sustainably. Since all the specific autoantibodies found in MG belong to the IgG isotype, 
agents that specifically lower the level of these antibodies without affecting the level of other 
isotypes such as IgA, IgE and IgM may be of special interest. 
One such strategy involves inhibition of the neonatal crystallizable fragment (Fc) receptor 
(FcRn). FcRn was shown to play a central role in trafficking IgGs and albumin into recycling 
pathways rescuing them from lysosomal degradation. Molecules that block the interaction of 
FcRn with IgGs are expected to induce degradation and fast clearance of pathogenic IgGs 
leading to a lowering of their serum level.6,7 
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Thus, targeting the FcRn-IgG interaction would be a rational therapeutic approach to rapidly 
clear pathogenic autoantibodies in IgG-driven autoimmune diseases such as MG. 
1.2. 
Investigational Medicinal Product 
Efgartigimod (ARGX-113) is a human IgG1-derived Fc fragment of the za allotype that binds 
with nanomolar affinity to human FcRn. Efgartigimod encompasses IgG1 residues D220-K447 
(EU numbering scheme) and has been modified with the so-called ABDEG™ technology 
(ABDEG™ = antibody that enhances IgG degradation)8 to increase its affinity for FcRn at both 
physiological and acidic pH. The increased affinity for FcRn of efgartigimod at both acidic and 
physiological pH results in a constitutively blockage of FcRn-mediated recycling of IgGs. 
Given the essential role of the FcRn receptor in IgG homeostasis, inhibiting this FcRn function, 
as achieved by efgartigimod, leads to rapid degradation of IgGs, which is expected to include 
autoantibodies in IgG-driven autoimmune diseases. 
This concept has been validated in various murine disease models together with 
pharmacokinetic/pharmacodynamic (PK/PD) studies in cynomolgus monkeys, either by using 
efgartigimod or a full-lengthmonoclonal antibody analog (HEL-ABDEG™).9,10 
The antibody clearing properties of efgartigimod were confirmed in PK/PD studies in 
cynomolgus monkeys. A single infusion of efgartigimod resulted in a decrease of IgG up to 55% 
without altering serum albumin concentrations nor IgM or IgA levels. This PD effect as 
measured with a tracer IgG molecule was proven to be more potent than intravenous 
immunoglobulin (IVIg), both in rapidity of onset as in depth of the effect. Repeated dosing could 
improve the PD effect up to a maximum IgG reduction of 75%. 
These nonclinical data validated the further development of efgartigimod for assessing its 
therapeutic potential in IgG-driven autoimmune indications. 
To date, a phase 1 (ARGX-113-1501) and a phase 2 (ARGX-113-1602) trial are completed as 
part of the clinical development of efgartigimod for the treatment of generalized myasthenia 
gravis (gMG).  
ARGX-113-1501 was a randomized, double-blind, placebo-controlled, First-in-Human (FIH) 
phase 1 trial conducted in 62 healthy volunteers to assess the safety and tolerability and to 
evaluate the PK and PD characteristics of single and multiple ascending intravenous (IV) doses 
of efgartigimod. The trial showed that a single administration of efgartigimod reduced IgG levels 
up to 50%, while multiple dosing further lowered IgGs up to approximately 70%. IgG levels 
returned to baseline approximately 8 weeks following the last administration of efgartigimod. IV 
administration of efgartigimod at single doses up to 25 mg/kg and multiple doses of 10 mg/kg 
and 25 mg/kg were safe and well tolerated.  
Based on an optimal PD effect combined with minimal number of observed adverse events 
(AEs) (compared to the 25 mg/kg dose level), the dose of 10 mg/kg once weekly for 4 weeks 
provided the most favorable risk-benefit profile and was therefore selected for further testing in 
the phase 2 trial. The outcome of the phase 2 trial indicated the efficacy and safety of 10 mg/kg 
in 4 weekly infusions in gMG patients 
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ARGX-113-1602 was a randomized, double-blind, placebo-controlled, multicenter phase 2 trial 
to evaluate the safety, efficacy, and PK of efgartigimod for the treatment of autoimmune MG 
patients with generalized muscle weakness. Eligible patients (24 in total) were randomized at a 
1:1 ratio to receive efgartigimod (10 mg/kg) or placebo in 4 infusions administered 1 week apart 
in addition to standard of care (SoC). The clinical effect of efgartigimod was explored in this 
trial using validated efficacy scales commonly used in MG clinical research and practice: 
Myasthenia Gravis Activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis 
(QMG), MGC, and MGQoL15r. The efficacy data of the 4 scales consistently point in the same 
direction and show a rapid onset of action, and a relevant and long-lasting clinical improvement 
over placebo. More specifically, on the MG-ADL scale, 75% of the patients treated with 
efgartigimod had a sustained clinically relevant reduction in total MG-ADL scores (defined as a 
reduction of at least 2 points from baseline) for a period of at least 6 consecutive weeks (starting 
at the latest 1 week after last infusion of investigational medicinal product [IMP]) versus 25% of 
patients on placebo (difference was found to be statistically significant). Furthermore, this 
clinical improvement observed in all scales was consistent with the observed PD data, namely a 
reduction of total IgG and subtypes and a decreased level of AChR autoantibodies. 
The proposed phase 3 trial aims to establish the safety and tolerability of efgartigimod in 
class II-IVb gMG patients, and thereby validating the concept of autoantibody reduction as a 
therapeutic treatment modality in this indication. 
This trial will be performed in compliance with the protocol, International Council for 
Harmonisation Good Clinical Practice (ICH GCP), Declaration of Helsinki, and other applicable 
regulatory requirements. 
1.3. 
Standard of Care and Rationale for the Use of Efgartigimod 
Several drugs and medical procedures are routinely used in the management of gMG. 
Acetylcholinesterase (AChE) inhibitors are frequently used in treating MG, particularly in the 
mild forms of the disease. These agents include drugs such as pyridostigmine, neostigmine, and 
edrophonium, and their effectiveness varies widely. These drugs act by inhibiting the enzyme 
AChE, which is responsible for the degradation of acetylcholine. This prolongs acetylcholine 
exposure, which leads to an amelioration of the signs/symptoms of MG. AChE inhibitors provide 
a symptomatic treatment of MG and do not act on the disease's underlying pathogenic 
mechanism. AChE inhibitors are not efficacious in all patients with MG and can have a short 
duration of action, necessitating dosing several times daily. 
Corticosteroids and non-steroidal immunosuppressive drugs (NSIDs) are also used in the 
treatment of MG. These drugs are frequently used in the more advanced stage of the disease. 
Corticosteroids and NSIDs are typically characterized by delayed onset of effects. Because of 
their multiple side effects, the lowest effective dose of corticosteroids is recommended for long-
term treatment that is often indicated for chronic conditions such as MG. NSIDs are commonly 
used and include azathioprine, mycophenolate mofetil, cyclosporine, and cyclophosphamide. 
The use of corticosteroids and NSIDs however is associated with dose-dependent, frequent and 
often serious side effects whose management requires to lower the dose and to use these drugs in 
various combinations to find the right balance between efficacy and side effects.2,3  
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Apart from the SoC described above, new biologic agents such as rituximab and eculizumab are 
also used to treat specific cases of MG, such as resistant and refractory forms. However, the use 
of these drugs is also associated with serious and sometimes life-threatening side effects.11,12  
Exacerbations of MG are treated using either therapeutic plasma exchange (PLEX), 
immunoadsorption or IVIg. In the case of PLEX, typically 1 exchange, removing 1 to 2 plasma 
volumes, is done every other day up to a total of 4 to 6 times, to improve muscle strength or 
ameliorate a myasthenic crisis. Unfortunately, this treatment is invasive and has frequent side 
effects such as hypotension, paresthesia, infections, and thrombotic complications. IVIg is 
widely used for patients with exacerbating MG. The mechanism of action of IVIg in MG is still 
unclear and may include interference with autoantibodies, B-cell modulation, saturation of FcRn 
and complement.13,14 In addition, the use of IVIg is burdensome for the patient. 
These approaches however are not always available in all clinical centers since they require 
specific facilities and instrumentation.2,3 
Finally, in selected cases, surgical removal of the thymus gland is also used to ameliorate the 
clinical manifestations of MG. However, thymectomy is not always effective in all patients and 
is associated with surgery-specific risks.2,3,15,16 
Following administration of efgartigimod (10 mg/kg) in 4 infusions administered 1 week apart in 
addition to SoC in patients with autoimmune MG with generalized muscle weakness in the phase 
2 trial (ARGX-113-1602, also see Section 1.2), overall efgartigimod was well tolerated and 
demonstrated a good safety profile consistent with phase 1 data. No serious or severe AEs were 
reported. The following events were reported as related to efgartigimod administration: 
rhinorrhea, gingivitis, headache, nausea, pruritus, paresthesia, myalgia, lymphocyte count 
decreased, monocyte count decreased, neutrophil count decreased, contusion, feeling hot, 
infusion site pain and pruritus, and herpes zoster. All these events were reported as mild, except 
the herpes zoster, which was considered as moderate and occurred in a patient concomitantly 
treated with a systemic corticosteroid and NSID. Efgartigimod demonstrated a relevant and long-
lasting improvement over placebo of the clinical manifestations of MG as measured by all 4 
clinical efficacy MG scales, which reached statistical significance at specific timepoints on the 
MG-ADL, QMG, and MGQoL15r scales. Pharmacokinetic, PD, and immunogenicity profiles 
were consistent with phase 1 data. In addition, a potent and long-lasting reduction of AChR 
autoantibodies was observed. 
Myasthenia gravis is considered a highly autoantibody driven disease. Efgartigimod is a highly 
targeted therapy postulated to result in reduced autoantibody levels. Results from the phase 2 
trial indicate that it induces a strong and long-lasting improvement of the disease as measured by 
different efficacy scales while showing a favorable safety profile. Furthermore, this clinical 
improvement was consistent with the observed PD data, namely a reduction of total IgG and 
subtypes and a decreased level of AChR autoantibodies. Therefore, efgartigimod is believed to 
be a promising treatment to reduce autoantibodies in gMG patients. 
1.4. 
Benefit-Risk Assessment 
Benefits 
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The clinical effect of efgartigimod was explored using clinical activity tools commonly used in 
MG clinical research and practice: total MG-ADL, QMG, MGC, and MG-QoL15r scores. A 
mean total score change from baseline in total MG-ADL, QMG, MGC, and MG-QoL15r scores 
was observed as early as day 8 in patients treated with efgartigimod. A long-lasting reduction in 
total MG-ADL and MGC scores was observed, with the reduction in total scores still seen at 
day 78 (end of study [EoS]). Efgartigimod showed a statistically significant reduction in total 
MG-ADL, QMG, and MG-QoL15r scores compared with placebo at specific time points, 
indicating a clinical improvement in efgartigimod treatment over placebo. For all MG scales, a 
greater maximum mean change from baseline (reduction) was observed in the efgartigimod 
treatment group compared with placebo. 
Eligible participants of trial ARGX-113-1704 will be offered the option to roll over to this 
follow-on trial where (re-)treatment of efgartigimod can be done on an “as needed basis,” which 
is a substantial benefit for the patient. 
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. SC administration is considered more convenient for 
patients than IV administration, especially if efgartigimod can be administered by the patient or 
caregiver at home. 
Risks 
No major safety findings have arisen in the ongoing and completed trials, nor any pattern of AEs 
which would raise concerns or alter the potential benefit-risk profile of efgartigimod.  
In the phase 3 trials in patients with gMG, the majority of TEAEs were reported as mild (grade 
1) or moderate (grade 2) in severity. The most frequently (≥5%) reported TEAEs during all 
cycles of efgartigimod 10 mg/kg treatment in the overall population who received at least 1 dose 
of efgartigimod were headache, nasopharyngitis, upper respiratory tract infection, diarrhea, 
urinary tract infection, nausea, myalgia, and oropharyngeal pain. TEAEs of severity of grade ≥3 
that occurred in >2 patients who received efgartigimod were headache and myasthenia gravis. 
The only TEAE that led to efgartigimod discontinuation reported in >2 patients was myasthenia 
gravis. No SAEs were assessed by the investigator as related to efgartigimod treatment. 
Four fatal cases have been reported, however, none of the fatal events were assessed by the 
investigator as related to efgartigimod treatment. Causes of death was unknown in a patient who 
died at home without witness. The other 3 patients died due to myasthenia gravis crisis, lung 
cancer Stage IV, and acute myocardial infarction. These 4 patients were between 55 and 79 years 
old and all had clear comorbidities, including underlying gMG. 
Adverse drug reactions were identified based on safety data from the phase 3 double-blind, 
placebo-controlled trial in patients with gMG and include upper respiratory tract infection, 
urinary tract infection, bronchitis, myalgia, and procedural headache.  
Due to the efgartigimod mechanism of action of reducing IgG levels, AEs in the Infections and 
Infestations SOC have been defined as AESIs. In the Phase 3 trials with efgartigimod IV in 
patients with gMG, the most frequently reported treatment-emergent AESIs by preferred term 
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(PT) were nasopharyngitis, upper respiratory tract infection, urinary tract infection, and 
bronchitis. Most AESIs were mild or moderate in severity. Few patients had severe or serious 
AESIs reported, and no SAEs of AESIs were assessed by the investigator as related to 
efgartigimod treatment. 
All therapeutic proteins have the potential to elicit immune responses, potentially resulting in 
hypersensitivity or allergic reactions. As with any IV injection, the potential exists for infusion-
related reactions (IRRs) to occur during or within 48 hours following the administration of 
efgartigimod. Overall, the frequency of IRRs in the clinical trials was low. At the PT level, no 
TEAEs of drug hypersensitivity or anaphylactic reaction were reported. None of the IRRs 
reported were serious. Most IRRs were mild in severity and no IRRs resulted in a change in 
efgartigimod administration. For administration of efgartigimod PH20 SC, the local injection site 
will be monitored during the trial. 
In the Phase 3 trial with efgartigimod IV in patients with gMG, no differences or imbalances 
were observed between the efgartigimod and placebo groups in the incidence or rates of 
abnormal values in clinical laboratory parameters. There was no reduction in levels of serum 
albumin with the administration of efgartigimod. In the extension trial in patients with gMG, the 
most frequently reported grade ≥3 abnormalities were lymphocyte count decreased. 
No clinically significant changes in vital signs and/or electrocardiogram (ECG) findings have 
been observed in clinical trials to date.  
Safety for use during pregnancy has not been established. Therefore, efgartigimod should not be 
administered to pregnant or lactating women. 
In summary, efgartigimod has been well tolerated in clinical trials conducted to date. 
Please refer to the current investigator’s brochure (IB) for a full safety and efficacy summary. 
An independent Data Safety Monitoring Board (DSMB) is responsible for ongoing safety 
monitoring during the trial and will meet on a regular basis (see Section 7.2.6). 
Considering the efficacy and safety data collected up to date and the design of the trial that has 
appropriate measures to ensure safe trial participation, which minimizes the risk to patients 
participating in this trial, the potential risks identified in association with efgartigimod are 
justified by the potential benefits gained by patients receiving efgartigimod. 
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2. 
TRIAL OBJECTIVES 
2.1. 
Primary Objective 
To evaluate the long-term safety and tolerability of efgartigimod in acetylcholine receptor 
antibody (AChR-Ab) seropositive patients.  
2.2. 
Secondary Objective 
To evaluate the long-term safety and tolerability of efgartigimod in the overall population 
(AChR-Ab seropositive and AChR-Ab seronegative patients). 
2.3. 
Tertiary Objectives 
Part A only: 
x To evaluate the disease severity as assessed by total MG-ADL score changes in 
AChR-Ab seropositive patients. 
x To evaluate the disease severity as assessed by total MG-ADL score changes in the 
overall population (AChR-Ab seropositive patients and AChR-Ab seronegative 
patients). 
x To evaluate disease severity as assessed by total QMG score changes in AChR-Ab 
seropositive patients. 
x To evaluate disease severity as assessed by total QMG score changes in the overall 
population (AChR-Ab seropositive patients and AChR-Ab seronegative patients). 
x To evaluate the effect of efgartigimod on PD (total IgG, IgG subtypes, autoantibodies 
[anti-AChR antibodies and anti-MuSK antibodies]). 
Part A and B: 
x To evaluate the immunogenicity of efgartigimod. 
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3. 
TRIAL ENDPOINTS 
3.1. 
Primary Endpoint 
Incidence and severity of AEs, serious adverse events (SAEs), vital signs, ECG and laboratory 
assessments over the duration of the trial in AChR-Ab seropositive patients. 
3.2. 
Secondary Endpoint 
Incidence and severity of AEs, SAEs, vital signs, ECG and laboratory assessments over the 
duration of the trial in the overall population (AChR-Ab seropositive patients and AChR-Ab 
seronegative patients). 
3.3. 
Tertiary Endpoints 
Part A only: 
x Total MG-ADL score changes compared to the treatment period baseline of the first 
cycle (TP1B) and the corresponding TPnB in AChR-Ab seropositive patients. 
x Total MG-ADL score changes compared to TP1B and the corresponding TPnB in the 
overall population (AChR-Ab seropositive and AChR-Ab seronegative patients). 
x Total QMG score changes compared to TP1B and the corresponding TPnB in AChR-
Ab seropositive patients. 
x Total QMG score changes compared to TP1B and the corresponding TPnB in the 
overall population (AChR-Ab seropositive and AChR-Ab seronegative patients). 
x Percentage decrease (compared to TP1B and the corresponding TPnB) of total IgG 
level and IgG subtypes in efgartigimod (re-)treated patients. 
x Percentage decrease (compared to TP1B and the corresponding TPnB) of 
autoantibodies (anti-AChR antibodies and anti-MuSK antibodies) in efgartigimod 
(re-)treated patients. 
Part A and B: 
x Incidence and prevalence of anti-drug antibodies (ADA) to efgartigimod. 
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4. 
INVESTIGATIONAL PLAN 
4.1. 
Summary of Trial Design 
Methodology 
DESCRIPTION 
This is a 3-year (maximum), single-arm, open-label, multicenter, phase 3 follow-on trial of 
ARGX-113-1704 to evaluate the long-term safety and tolerability of efgartigimod in patients 
with gMG. The trial consists of 2 parts: Part A (1 year) and Part B (up to maximum 2 years or 
until efgartigimod becomes commercially available or another option to access efgartigimod is 
available, whichever option comes first. The additional part (Part B) was added to ARGX-113-
1705 in order to provide the patients with the chance to have access to efgartigimod while it is 
not yet commercially available or available through another patient program. This extension will 
also enable additional long-term safety and tolerability data to be collected. 
A variable number of treatment periods consisting of 4 weekly infusions of efgartigimod 
(10 mg/kg of body weight) infused over a period of 3 weeks will be administered to eligible 
patients on an “as needed basis” on top of their SoC. The time between treatment periods is 
based on the duration of the treatment effect and may vary from patient to patient and within 
each patient from period to period (patient-tailored approach). 
The first visit of trial ARGX-113-1705 will coincide with the last visit of trial ARGX-113-1704 
for each patient.  
The SEB will be set at the first trial visit, while the baseline of each subsequent treatment period 
(TPnB for Part A or TPEnB for Part B) will be set at visit 1 of each corresponding treatment 
period. 
ROLL-OVER 
At the EoS visit of trial ARGX-113-1704, eligible patients will be offered the option to roll over 
into this trial. Patients in need of (re-)treatment in trial ARGX-113-1704 but who cannot 
complete a Treatment Cycle within the time frame of that trial, may immediately roll over to this 
trial to receive treatment with efgartigimod.  
Patients who discontinued early from trial ARGX-113-1704 or discontinued early from 
randomized treatment for rescue or pregnancy reasons or for an SAE that is likely to result in a 
life-threatening situation or pose a serious safety risk in that trial will not be offered the option to 
roll over into this trial.  
Patients who discontinued early from randomized treatment for other reasons and patients who 
had a temporary interruption from randomized treatment in trial ARGX-113-1704 may be 
offered the option to roll over into this trial. 
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. 
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Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early 
discontinuation (ED) visit assessments specified in Table 2. The previous efgartigimod IV dose 
must have been received at least 30 days before entry into ARGX-113-2002. 
Patients can enroll in ARGX-113-2002 until recruitment for this study is closed. Patients who 
enroll in ARGX-113-2002 will not return to ARGX-113-1705. 
(RE-)TREATMENT (Part A) 
Each patient will start a (new) treatment period with efgartigimod when all of the following 
criteria are met:  
x The patient has completed the previous treatment period (ie, after visit 4) 
x The patient has a total MG-ADL score of ≥5 points with more than 50% of the total 
score due to non-ocular symptoms 
x The patient has a reduction in the total MG-ADL score of <2 points compared to the 
score at: 
1. The last treatment cycle baseline (TCB) in trial ARGX-113-1704 for the first 
treatment period (TP1) in trial ARGX-113-1705 
2. The last treatment period Baseline (TPnB) for all subsequent treatment periods 
(TPn+1) in trial ARGX-113-1705 
However, patients may not receive (re-)treatment with efgartigimod if, at the time of 
(re-)treatment, they have clinical evidence of bacterial, viral or fungal disease, or any other 
significant disease which could confound the results of the trial or put patients at undue risk. 
Patients who require an additional treatment but who are not eligible to receive (re-)treatment for 
the reasons listed here will remain in the trial to receive appropriate alternative MG treatment 
(see Appendix 5 and Appendix 6). 
Patients who have a treatment failure to efgartigimod for 3 consecutive treatment periods will be 
discontinued from the trial. Treatment failure means the absence of a decrease of at least 2 points 
in total MG-ADL score compared to the corresponding TPnB in at least 50% of the assessments 
(ie, TPnV2, TPnV3, TPnV4, and the first posttreatment period visit).  
If a patient becomes eligible for (re-)treatment with efgartigimod by meeting the criteria for the 
total MG-ADL score as stated in Section 4.1, but cannot complete the entire treatment period 
during Part A (ie, after day 336) then the patient can be transitioned to Part B after completing 
the end of Part A (EoA) visit assessments (Table 1). These assessments should be completed 
even if the patient is unwilling or unable to continue to Part B. 
The transition to Part B can be either at ITPE0Vn or TPE1V1, depending on the patient status 
regarding the need for (re-)treatment upon transition from Part A. The first visit in Part B will 
always coincide with the EoA visit in Part A. The assessments done for the last visit in Part A 
should not be repeated in Part B. 
(RE-)TREATMENT (Part B) 
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If the patient feels that his/her condition has deteriorated, then the investigator may start a new 
treatment period at an intertreatment period (ITPE) visit or the patient may contact the 
investigator to attend an unscheduled visit. 
A patient can start the next treatment period and receive efgartigimod if all of the following 
criteria are met:  
x The patient has completed the previous treatment period (ie, after visit 4)* 
x The investigator determines that the patient will benefit from re-treatment 
x There is at least 1 calendar month (minimum 4 weeks) between treatment periods (ie, 
between TPEnV4 and TPEn+1V1) 
*A patient who has had a temporary interruption of trial treatment in Part A may also continue 
into Part B of the trial and receive (re-)treatment if the conditions in Section 4.4.1 are met. 
However, patients may not receive (re-)treatment with efgartigimod if, at the time of 
(re-)treatment, they have clinical evidence of bacterial, viral or fungal disease, or any other 
significant disease which could confound the results of the trial or put patients at undue risk. 
If a patient becomes eligible for (re-)treatment with efgartigimod but cannot complete the entire 
treatment period within the duration of the trial, the patient should continue to the EoS visit. 
If the investigator considers that the patient will not have a clinical benefit from (re-)treatment 
then the patient cannot start a new treatment period. The patient should then continue to the EoS 
visit. 
STANDARD OF CARE (SoC) 
In Part A: 
Permitted SoC for MG treatment under this protocol include NSIDs (eg, azathioprine, 
methotrexate, cyclosporine, tacrolimus, mycophenolate mofetil, and cyclophosphamide), 
steroids, as well as acetylcholinesterase (AChE) inhibitors.  
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment 
of the SoC dose and/or frequency) is not allowed: 
x From trial entry until 1 week after the last infusion of the first treatment period. 
x From the first infusion until 1 week after the last infusion of each subsequent 
treatment period. 
From 1 week after the last infusion of each treatment period up to and prior to the administration 
of the first infusion of the next treatment period, a dose reduction in SoC consistent with current 
medical practice is allowed. 
In case these medications are taken for another indication than MG, same conditions apply. 
Administration of AChE inhibitors must be halted for at least 12 hours prior to performing the 
QMG assessment. Following this requirement, this possible temporary change in dosing regimen 
of AChE inhibitors will not be considered as a change in SoC. 
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In Part B: 
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment 
of the SoC dose and/or frequency) is allowed, without restrictions, following current medical 
practice. 
PLEX, intravenous immunoglobulin (IVIg), immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current corticosteroids used as stand-alone therapy or 
in combination is also allowed in Part B. 
TIME BETWEEN TREATMENT PERIODS 
At the end of each treatment period, patients will enter a variable intertreatment period during 
which they will be treated with their SoC only. The length of the intertreatment period may vary 
from patient to patient and for each patient from period to period (patient-tailored approach). For 
Part A, the visit frequency in the Intertreatment period is every 30 days (± 2 days) after the 
previous visit. For Part B, the visit frequency in the intertreatment period is every 90 days (± 7 
days) after the previous visit. If an ITP visit for Part A is scheduled within 14 days of the EoA 
visit, then the EoA visit should be performed instead. 
RESCUE THERAPY (Part A only) 
Rescue therapy will be limited to PLEX, IVIg, immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current corticosteroids used as stand-alone therapy or 
in combination. Rescue therapy is permitted for patients experiencing protocol-defined MG 
clinical deterioration AND if in addition the treating physician believes that the patient’s health 
is in jeopardy if rescue therapy is not given. An MG clinical deterioration permitting rescue 
therapy to be given is defined as a patient experiencing at least 1 of the following: (1) new or 
worsening of respiratory / bulbar symptoms or (2) at least 2-point increase of individual non-
ocular MG-ADL items. Whenever possible, prior to giving rescue therapy to a patient, the 
Medical Director at the sponsor and the Medical Monitor at the sponsor’s designated contract 
research organization (CRO) should be informed. 
In situations where the treatments as listed above are given under the protocol-defined rescue 
criteria, patients will be discontinued early from the trial. 
EARLY DISCONTINUATION  
For patients who discontinue early from trial, the assessments will depend on the visit at which it 
was decided that the patient had to discontinue (see Section 5.4, Figure 1, and Figure 2). 
Patients who discontinue early from the trial within a treatment period should perform the 
planned assessments of the corresponding treatment period visit. These patients will not receive 
any further administration of efgartigimod during the trial and will return for the ED visit 1 
month (30 ± 2 days) after the last dose administration. An unscheduled visit can be organized if 
deemed necessary by the investigator. 
Patients who discontinue early from the trial between the last visit of a treatment period (TPnV4 
or TPEnV4) and the next intertreatment period visit (ITPnVn or ITPEnVn) should perform the ED 
assessments 1 month (30 ± 2 days) after the last dose administration. 
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Patients who discontinue early from the trial at the ITP (Part A) or ITPE (Part B) visit should 
perform the ED assessments instead of the ITPnVn (Part A) or ITPEnVn (Part B) assessments. 
Patients who discontinue early from the trial after the ITP (Part A) or ITPE (Part B) visit should 
perform the ED assessments. 
Any patient prematurely discontinuing the trial during Part A should perform the EoA/ED 
assessments according to the General Schedule of Assessments for Part A (Table 1). Any patient 
prematurely discontinuing the trial during Part B should perform the EoS/ED assessments for 
Part B (Table 2). 
Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early 
discontinuation (ED) visit assessments specified in Table 2. The previous efgartigimod IV dose 
must have been received at least 30 days before entry into ARGX-113-2002. Patients who enroll 
in ARGX-113-2002 will not return to ARGX-113-1705. 
TEMPORARY INTERRUPTION FROM TRIAL TREATMENT 
A patient who does not need to be discontinued early from the trial might still have a temporary 
interruption from trial treatment, which is defined as discontinuation only from the current 
treatment period. Therefore, these patients might still be eligible for further additional treatments 
with efgartigimod within this trial. 
Patients for whom treatment is interrupted will have to complete the current treatment period and 
will continue the trial as per the General Schedule of Assessments for Part A (Table 1) or for 
Part B (Table 2) but without drug administration. A patient who has had a temporary interruption 
of trial treatment in Part A may also continue into Part B of the trial and receive (re-)treatment if 
the conditions mentioned above are met. 
A schematic of the trial design is presented in Figure 1 for Part A and in Figure 2 for Part B. 
4.2. 
Discussion of Trial Design 
In the current trial, efgartigimod will be administered in patients with gMG, with the aim to 
evaluate the long-term safety and tolerability of efgartigimod.  
This trial is designed as a 3-year (maximum), single-arm, open-label, follow-on trial of 
ARGX-113-1704. The trial consists of 2 parts: Part A (1 year) and Part B (up to maximum 
2 years or until efgartigimod becomes commercially available or another option to access 
efgartigimod is available, whichever option comes first. The additional part (Part B) was added 
to ARGX-113-1705 in order to provide the patients with the chance to have access to 
efgartigimod while it is not yet commercially available or available through another patient 
program. This extension will also enable additional long-term safety and tolerability data to be 
collected. 
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. 
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With the exception of patients who discontinued early from trial ARGX-113-1704 or patients 
who discontinued early from trial treatment for rescue or pregnancy reasons or an SAE that is 
likely to result in a life-threatening situation or pose a serious safety risk, all participants of trial 
ARGX-113-1704 who reached the EoS visit are allowed to roll over into this trial.  
The first visit of trial ARGX-113-1705 will coincide with the last visit of trial ARGX-113-1704 
for each patient. 
In the same way, with the exception of patients who discontinued early from Part A of this trial, 
all participants of Part A who reached the EoA visit can be transitioned to Part B of this trial. 
The first visit of Part B of this trial will coincide with the last visit of Part A for each patient. 
Efgartigimod will be administered to eligible patients on an “as needed basis” on top of their 
SoC in treatment periods. This SoC serves as a rational therapeutic approach for IgG-mediated 
immune diseases such as MG by targeting the FcRn-IgG interaction and alleviating autoimmune 
disease symptoms by rapidly clearing pathogenic autoantibodies. The time between treatment 
periods is based on the duration of the treatment effect and may vary from patient to patient and 
within each patient from period to period (patient-tailored approach). 
In Part A, a change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or 
adjustment of the SoC dose and/or frequency) is not allowed from trial entry until 1 week after 
the last infusion of the first treatment period, and from the first infusion until 1 week after the 
last infusion of each subsequent treatment period. From 1 week after the last infusion of each 
Treatment Period up to and prior to the administration of the first infusion of the next treatment 
period, a dose reduction in SoC consistent with current medical practice is allowed. 
In Part B, a change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or 
adjustment of the SoC dose and/or frequency) is allowed without restrictions, following current 
medical practice. 
PLEX, IVIg, immunoadsorption or use of a new type of corticosteroid or an increased dose of 
the current corticosteroids used as stand-alone therapy or in combination is also allowed in Part 
B. 
The chosen primary and secondary endpoints in this trial are to evaluate the long-term safety and 
tolerability of efgartigimod over the duration of the trial, as well as by cycle, in AChR-Ab 
seropositive patients and in the overall population (AChR-Ab seropositive and seronegative 
patients). 
Both MG AChR-Ab seropositive as well as MG AChR-Ab seronegative patients will be included 
in the trial. AChR-Ab seronegative patients are patients in which AChR-Ab cannot be detected 
in serum using routine laboratory methods. However, there is evidence that in these seronegative 
patients, MG is also driven by other autoantibodies of the Ig class, such as MuSK, LRP4 or by 
other so far unidentified autoantibodies to other antigens of the neuromuscular junction. In 
addition, in other cases, the absence of AChR-Ab may be due to the insufficient sensitivity of the 
routine assays which are unable to detect low affinity autoantibodies. Therefore, given the 
mechanism of action of efgartigimod and the IgG pathogenesis of MG in most of the so-called 
seronegative patients, there is reason to believe that, similarly to the AChR-Ab seropositive 
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patients, AChR-Ab seronegative patients will also benefit from treatment with efgartigimod. The 
dose regimen selected for this trial is the same as in trial ARGX-113-1704.  
The choice of the dose/regimen of efgartigimod (4 weekly infusions of 10 mg/kg) was made 
because, as observed in a phase 1 trial in human volunteers, it causes a marked and long-lasting 
decrease of IgG level believed to be related to efficacy with only few mild AEs. In the same trial, 
higher doses did not result in significant further reductions of IgG while, at the same time, the 
number of subjects experiencing efgartigimod-related AEs increased. On the other hand, a lower 
dose of 2 mg/kg resulted in substantially less reduction of IgG concentrations (2.3-fold 
difference in maximum IgG decrease). As suggested by the PK/PD modeling, lower doses 
(eg, 5 mg/kg) will result in a less marked decrease of the IgG level and therefore may result in a 
less pronounced therapeutic effect. In addition, in a phase 2 trial (ARGX-113-1602) in patients 
with gMG, the dose/regimen chosen for the current trial induced a clinically meaningful 
improvement on the MG-ADL and QMG scales and, at the same time, confirming the acceptable 
safety profile of the drug. Therefore, the dose of 10 mg/kg of efgartigimod administered weekly 
for 4 weeks seems to provide the best benefit/risk ratio and was selected for future trials.  
All safety and disease severity assessments used in this trial are standard, ie, widely used and 
generally recognized as reliable, accurate, and relevant. 
4.3. 
Selection of Trial Population 
4.3.1. 
Inclusion Criteria 
Patients will roll over in this trial only if they meet all of the following criteria: 
1. Patients with the ability to understand the requirements of the trial, provide 
written informed consent, and can comply with the trial protocol procedures. 
2. Patients who participated in trial ARGX-113-1704 and are eligible for roll over, 
ie: 
 Patients who reached EoS at day 182 in trial ARGX-113-1704. 
 Patients who need (re-)treatment in trial ARGX-113-1704 but cannot complete a 
Treatment Cycle within the time frame of that trial may immediately roll over into 
this trial to receive treatment with efgartigimod. 
 Patients who discontinued early from randomized treatment for other reasons than 
pregnancy, rescue therapy or an (S)AE in trial ARGX-113-1704 may be offered 
the option to roll over into this trial. 
 Patients who had a temporary interruption from randomized treatment in trial 
ARGX-113-1704 may be offered the option to roll over into this trial. 
3. Patients are required to be on a stable dose of their MG treatment (SoC) prior to 
SEB. The SoC is limited to AChE inhibitors, steroids and NSIDs (eg, 
azathioprine, methotrexate, cyclosporine, tacrolimus, mycophenolate mofetil, and 
cyclophosphamide). 
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Note: AChE inhibitors must be withheld for at least 12 hours consistent with the revised manual 
for the QMG test as recommended by the Myasthenia Gravis Foundation of America (MGFA), 
before the QMG assessment. 
4.3.2. 
Exclusion Criteria 
Patients will not roll over in this trial if they meet any of the following criteria: 
1. Patients who discontinued early from trial ARGX-113-1704 or patients who 
discontinued early from randomized treatment for pregnancy or rescue reasons or 
an SAE that is likely to result in a life-threatening situation or pose a serious 
safety risk. 
2. Pregnant and lactating women, and those intending to become pregnant during the 
trial or within 90 days after the last dosing. Women of childbearing potential 
(DEFINITION OF TERMS) should have a negative urine pregnancy test at SEB. 
The contraceptive requirements for women of childbearing potential are described 
in Appendix 8:Temporary Changes to Study Procedures in ARGX-113-1705 
Related to the COVID-19 Pandemic 
Introduction 
As the COVID-19 pandemic poses issues for both sites and patients and presents unprecedented 
challenges in uncharted territory, this crisis prompted the sponsor to perform a critical review of 
both efgartigimod administration and changes needed to the study in order to safeguard patient 
safety, while still being able to gather additional data.  
The risk/benefit, safety profile, guidance for site conduct in terms of visits and assessments, as 
well as data entry, and potential changes in the Schedule of Assessments are included below. 
Safety of Efgartigimod: Mechanism of Action, Pharmacodynamics and Risk/Benefit in  
Patient Safety 
Efgartigimod administration results in a targeted reduction in levels of all IgG subtypes. 
However, and more importantly, it does not impact levels of other immunoglobulin isotypes, 
such as IgA and IgM. Other elements of the immune system are not impacted by efgartigimod 
treatment. 
Efgartigimod induces a targeted reduction of IgG levels, without impacting IgG production. The 
maximum mean reduction in total IgG is approximately 70%; therefore, residual IgG and other 
immunoglobulin levels remain constant during treatment. It is therefore anticipated that patients 
can mount an immune response. In support of this, experiments in FcRn knockout animals and in 
animals treated with FcRn antagonist demonstrated that a specific immune response was 
obtained following an antigen trigger, albeit with reduced (antigen-specific) IgG titers. 
Additionally, after ceasing efgartigimod treatment, IgG recycling returns and total IgG levels 
increase and return to baseline levels within a few weeks. 
Looking at administration in humans, efgartigimod treatment at doses ≥10 mg/kg have been 
administered to more than 120 healthy volunteers and patients with generalized myasthenia 
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gravis (gMG), immune thrombocytopenia, and pemphigus in studies carried out prior to phase 3 
studies. No general or infection-related safety concerns were identified.  
The phase 3 ADAPT gMG study enrolled 167 patients and data will be available in mid-2020. 
An active assessment of adverse event reports during the study remains ongoing. Although the 
phase 3 ADAPT data are blinded, no safety concern has been identified to date. 
Available data from trials of other FcRn antagonists have not identified any increased risk of 
infection. 
 
ADAPT/ADAPT+: Pre-existing Safety Measures and Changes to Be Implemented in the 
Current Situation 
The phase 3 ADAPT study implements multiple layers of safety measures and reporting. 
Efgartigimod is administered in treatment cycles, in which 4-weekly infusions are followed by 
additional treatment cycles that are administered according to clinical need. Therefore, during the 
follow-up period after each treatment cycle, FcRn recycling resumes and IgG levels begin to 
increase. 
The protocol gives guidance to temporarily or permanently discontinue treatment when the 
patient has signs of clinically significant of bacterial, viral, or fungal infection, in order to treat 
the underlying condition. The treatment can be initiated at a later time once the clinically 
significant infection has been deemed resolved. A Treatment Period can be considered as 
interrupted if the patient is not able to visit the site for more than 1 visit. In such cases, a new 
Treatment Period can be initiated at a later date. 
Additionally, any case of infection is regarded as an adverse event of special interest (AESI) and 
is subject to structured safety reporting with standardized questions in the eCRF. 
The current COVID-19 situation warrants new measures to be introduced for patient safety. 
These measures will allow patients to be evaluated remotely if/when quarantine is imposed. For 
example, any remaining visits in an interrupted Treatment Period, may be performed remotely, in 
cases where the patient is not allowed or cannot physically visit the site. These measures respect 
both patient safety and local guidance, as well as allowing basic safety data to be collected. 
The assessments identified for telephone assessment visits are highlighted with the use of bold 
italics in the existing Schedule of Assessments for Part A in Table 1 and for Part B in Table 2. 
Guidance on the execution of these visits and assessments is given below. 
By providing a structured back-up plan, we aim to mitigate the risks of the COVID-19 pandemic, 
while still respecting both patient safety and collection of safety data and remaining compliant 
with GCP. 
 
Visits with the possibility of remote assessment by telephone: 
TPxV2, TPExV2, TPxV3, TPExV3, TPxV4, TPExV4, ITPxVx, ITPExVx, EoA, EoS, ED, and 
UNS. See the Schedule of Assessments for Part A (Table 1) and for Part B (Table 2). 
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Treatment Period visits will be replaced by telephone assessment visits during the current 
COVID-19 situation when the Treatment Period is considered interrupted.  
 
Mandatory physical visits: 
Initiating a new Treatment Period can only be done when the patient is physically on site. 
 
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Guidance to Sites in Case of Suspected COVID-19 in Patients 
As sponsor we want to emphasize and highlight the need to follow the guidance issued by local 
authorities. Wherever guidance is unclear, or if no specific guidance is available, argenx will 
recommend to either postpone the visit if possible or evaluate the need for telephone assessments 
to replace a physical visit. 
The site should contact the patient prior to each visit, and conduct the following COVID-19 
assessments: 
 
1. Does the patient have symptoms, such as cough, fever, muscle pain, shortness of breath*? 
- If NO: Go to Questions 2 and 3. 
- If YES: 
• The patient should be tested for COVID-19:  
The investigator needs to document a positive COVID-19 test as an AESI. The anonymized 
result needs to be sent to the sponsor for filing. If COVID-19 safety measures are stopped 
according to local regulations, COVID-19 tests should continue to be performed and the 
results sent to the sponsor. 
*Shortness of breath includes an otherwise unexplained deterioration in the patient’s MG-
ADL score for breathing. In cases where the MG-ADL score for breathing is 2 or 3 
additional COVID-19 testing should be carried out. The exception to this is when a patient 
has an MG-ADL score for breathing of 2 at baseline. In such cases the patient should only be 
tested when the MG-ADL score for breathing returns to 2 after previous improvement or 
when it deteriorates to 3. 
The visit will only take place once the patient has a negative test for COVID-19. The planned 
visit may need to be rescheduled or can be replaced by a telephone assessment visit. If the 
patient was in a treatment cycle, the treatment will have to be interrupted. A new treatment 
cycle may be initiated later. Remaining visits in the Treatment Period can be performed 
as telephone assessment visits. 
• If the patient is tested and found to be COVID-19 negative:  
The patient can come to the next visit as scheduled. Follow-up of the patient should be done 
according to the protocol (decision to be taken if treatment can be given or is to be 
postponed). 
• If the patient is tested and found to be COVID-19 positive:  
The patient can only come to the site once he/she has a negative test for COVID-19, and so 
the planned visit may need to be rescheduled or replaced by a telephone assessment visit. If 
the patient was in a treatment cycle, the treatment will have to be interrupted. A new 
treatment cycle may be initiated later. The remaining visits in the Treatment Period can 
be replaced by telephone assessment visits. 
 
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2. The patient has no Corona-like symptoms and is not aware of any contact he/she may have 
had with someone who tested positive for COVID-19:  
• The visit can proceed as planned. If the patient cannot physically come to the clinic due to the 
local COVID-19 situation, the visit can be replaced by a telephone assessment visit. 
 
3. The patient has no Corona-like symptoms but has been in contact with someone who tested 
positive for Corona virus: 
• If the contact was 14 days or longer before the study visit => the visit can go ahead as planned. 
If the patient cannot physically come to the clinic due to the local COVID-19 situation, the visit 
can be replaced by a telephone assessment visit. 
• If the contact was less than 14 days before the study visit => the visit needs to be rescheduled at 
least 14 days after the contact occurred or be replaced by a telephone assessment visit. 
 
How to: Information related to study procedures and data collection 
The assessments deemed suitable for telephone consultation are: 
x Re-consenting where warranted, MG-ADL, Adverse Event and Concomitant 
Medication questioning.  
Since QMG needs quantification by the physician, using specific equipment, such as a 
dynamometer and spirometer, this assessment is not deemed suitable for telephone assessment.  
Telephone consultation will allow safety data to be collected and to check on the patient’s well-
being, while the derived MG-ADL score may give an indication of the need for another 
treatment with efgartigimod. 
Re-consenting with the updated ICF, or consent to Part B of the ADAPT+ study can be done 
remotely in view of the COVID-19 situation.  
Options for consent might entail: 
x physical signature by sending the ICF to the patient by courier and having a phone 
call with the patient, then having the signed document sent back to the site. 
x phone call with the patient, asking for email confirmation to corroborate verbal 
consent. 
x organize a conference call or video call together with the patient and impartial 
witness, where needed. 
x if no phone call or video call is possible, email documented consent. 
Depending on regional requirements the options can be limited, after consultation with the 
relevant IRB/IEC and/or regulatory authority. 
Data collected during a telephone assessment visit can be entered into the e-CRF pages of the 
corresponding “missed” visit. Enter the date of the phone call as the “date of visit” and enter the 
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data obtained in the applicable CRF pages. For the assessments that are not performed, answer 
“no” to the question if the assessment was made in the respective forms. Add “COVID-19 
telephone” in the comment section of the CRF. 
If you are not able to contact the patient, inactivate the full study visit in the CRF and confirm 
the missing visit in the comments section as “COVID-19.” 
Other than conducting telephone assessments, there may be other changes in the current practice 
on site. Halting spirometry in COVID-19 patients may be required, or only allowing use of a 
dedicated spirometry device (for contamination reasons).  There can be a temporary halt in 
performing this assessment, or conducting a partial assessment is also permitted. 
In order to give a clear overview of protocol deviations related to the specific COVID-19 
situation, dedicated protocol deviations with the COVID-19 label have been created to which any 
missed visit or assessment can be attributed. 
 
3. APPENDIX 9. 
4. Male patients who are sexually active and do not intend to use effective methods 
of contraception (as mentioned above) 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. The contraceptive requirements for male patients are 
described in Appendix 8: Temporary Changes to Study Procedures in ARGX-
113-1705 Related to the COVID-19 Pandemic 
Introduction 
As the COVID-19 pandemic poses issues for both sites and patients and presents unprecedented 
challenges in uncharted territory, this crisis prompted the sponsor to perform a critical review of 
both efgartigimod administration and changes needed to the study in order to safeguard patient 
safety, while still being able to gather additional data.  
The risk/benefit, safety profile, guidance for site conduct in terms of visits and assessments, as 
well as data entry, and potential changes in the Schedule of Assessments are included below. 
Safety of Efgartigimod: Mechanism of Action, Pharmacodynamics and Risk/Benefit in  
Patient Safety 
Efgartigimod administration results in a targeted reduction in levels of all IgG subtypes. 
However, and more importantly, it does not impact levels of other immunoglobulin isotypes, 
such as IgA and IgM. Other elements of the immune system are not impacted by efgartigimod 
treatment. 
Efgartigimod induces a targeted reduction of IgG levels, without impacting IgG production. The 
maximum mean reduction in total IgG is approximately 70%; therefore, residual IgG and other 
immunoglobulin levels remain constant during treatment. It is therefore anticipated that patients 
can mount an immune response. In support of this, experiments in FcRn knockout animals and in 
animals treated with FcRn antagonist demonstrated that a specific immune response was 
obtained following an antigen trigger, albeit with reduced (antigen-specific) IgG titers. 
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Additionally, after ceasing efgartigimod treatment, IgG recycling returns and total IgG levels 
increase and return to baseline levels within a few weeks. 
Looking at administration in humans, efgartigimod treatment at doses ≥10 mg/kg have been 
administered to more than 120 healthy volunteers and patients with generalized myasthenia 
gravis (gMG), immune thrombocytopenia, and pemphigus in studies carried out prior to phase 3 
studies. No general or infection-related safety concerns were identified.  
The phase 3 ADAPT gMG study enrolled 167 patients and data will be available in mid-2020. 
An active assessment of adverse event reports during the study remains ongoing. Although the 
phase 3 ADAPT data are blinded, no safety concern has been identified to date. 
Available data from trials of other FcRn antagonists have not identified any increased risk of 
infection. 
 
ADAPT/ADAPT+: Pre-existing Safety Measures and Changes to Be Implemented in the 
Current Situation 
The phase 3 ADAPT study implements multiple layers of safety measures and reporting. 
Efgartigimod is administered in treatment cycles, in which 4-weekly infusions are followed by 
additional treatment cycles that are administered according to clinical need. Therefore, during the 
follow-up period after each treatment cycle, FcRn recycling resumes and IgG levels begin to 
increase. 
The protocol gives guidance to temporarily or permanently discontinue treatment when the 
patient has signs of clinically significant of bacterial, viral, or fungal infection, in order to treat 
the underlying condition. The treatment can be initiated at a later time once the clinically 
significant infection has been deemed resolved. A Treatment Period can be considered as 
interrupted if the patient is not able to visit the site for more than 1 visit. In such cases, a new 
Treatment Period can be initiated at a later date. 
Additionally, any case of infection is regarded as an adverse event of special interest (AESI) and 
is subject to structured safety reporting with standardized questions in the eCRF. 
The current COVID-19 situation warrants new measures to be introduced for patient safety. 
These measures will allow patients to be evaluated remotely if/when quarantine is imposed. For 
example, any remaining visits in an interrupted Treatment Period, may be performed remotely, in 
cases where the patient is not allowed or cannot physically visit the site. These measures respect 
both patient safety and local guidance, as well as allowing basic safety data to be collected. 
The assessments identified for telephone assessment visits are highlighted with the use of bold 
italics in the existing Schedule of Assessments for Part A in Table 1 and for Part B in Table 2. 
Guidance on the execution of these visits and assessments is given below. 
By providing a structured back-up plan, we aim to mitigate the risks of the COVID-19 pandemic, 
while still respecting both patient safety and collection of safety data and remaining compliant 
with GCP. 
 
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Visits with the possibility of remote assessment by telephone: 
TPxV2, TPExV2, TPxV3, TPExV3, TPxV4, TPExV4, ITPxVx, ITPExVx, EoA, EoS, ED, and 
UNS. See the Schedule of Assessments for Part A (Table 1) and for Part B (Table 2). 
Treatment Period visits will be replaced by telephone assessment visits during the current 
COVID-19 situation when the Treatment Period is considered interrupted.  
 
Mandatory physical visits: 
Initiating a new Treatment Period can only be done when the patient is physically on site. 
 
Guidance to Sites in Case of Suspected COVID-19 in Patients 
As sponsor we want to emphasize and highlight the need to follow the guidance issued by local 
authorities. Wherever guidance is unclear, or if no specific guidance is available, argenx will 
recommend to either postpone the visit if possible or evaluate the need for telephone assessments 
to replace a physical visit. 
The site should contact the patient prior to each visit, and conduct the following COVID-19 
assessments: 
 
1. Does the patient have symptoms, such as cough, fever, muscle pain, shortness of breath*? 
- If NO: Go to Questions 2 and 3. 
- If YES: 
• The patient should be tested for COVID-19:  
The investigator needs to document a positive COVID-19 test as an AESI. The anonymized 
result needs to be sent to the sponsor for filing. If COVID-19 safety measures are stopped 
according to local regulations, COVID-19 tests should continue to be performed and the 
results sent to the sponsor. 
*Shortness of breath includes an otherwise unexplained deterioration in the patient’s MG-
ADL score for breathing. In cases where the MG-ADL score for breathing is 2 or 3 
additional COVID-19 testing should be carried out. The exception to this is when a patient 
has an MG-ADL score for breathing of 2 at baseline. In such cases the patient should only be 
tested when the MG-ADL score for breathing returns to 2 after previous improvement or 
when it deteriorates to 3. 
The visit will only take place once the patient has a negative test for COVID-19. The planned 
visit may need to be rescheduled or can be replaced by a telephone assessment visit. If the 
patient was in a treatment cycle, the treatment will have to be interrupted. A new treatment 
cycle may be initiated later. Remaining visits in the Treatment Period can be performed 
as telephone assessment visits. 
• If the patient is tested and found to be COVID-19 negative:  
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The patient can come to the next visit as scheduled. Follow-up of the patient should be done 
according to the protocol (decision to be taken if treatment can be given or is to be 
postponed). 
• If the patient is tested and found to be COVID-19 positive:  
The patient can only come to the site once he/she has a negative test for COVID-19, and so 
the planned visit may need to be rescheduled or replaced by a telephone assessment visit. If 
the patient was in a treatment cycle, the treatment will have to be interrupted. A new 
treatment cycle may be initiated later. The remaining visits in the Treatment Period can 
be replaced by telephone assessment visits. 
 
2. The patient has no Corona-like symptoms and is not aware of any contact he/she may have 
had with someone who tested positive for COVID-19:  
• The visit can proceed as planned. If the patient cannot physically come to the clinic due to the 
local COVID-19 situation, the visit can be replaced by a telephone assessment visit. 
 
3. The patient has no Corona-like symptoms but has been in contact with someone who tested 
positive for Corona virus: 
• If the contact was 14 days or longer before the study visit => the visit can go ahead as planned. 
If the patient cannot physically come to the clinic due to the local COVID-19 situation, the visit 
can be replaced by a telephone assessment visit. 
• If the contact was less than 14 days before the study visit => the visit needs to be rescheduled at 
least 14 days after the contact occurred or be replaced by a telephone assessment visit. 
 
How to: Information related to study procedures and data collection 
The assessments deemed suitable for telephone consultation are: 
x Re-consenting where warranted, MG-ADL, Adverse Event and Concomitant 
Medication questioning.  
Since QMG needs quantification by the physician, using specific equipment, such as a 
dynamometer and spirometer, this assessment is not deemed suitable for telephone assessment.  
Telephone consultation will allow safety data to be collected and to check on the patient’s well-
being, while the derived MG-ADL score may give an indication of the need for another 
treatment with efgartigimod. 
Re-consenting with the updated ICF, or consent to Part B of the ADAPT+ study can be done 
remotely in view of the COVID-19 situation.  
Options for consent might entail: 
x physical signature by sending the ICF to the patient by courier and having a phone 
call with the patient, then having the signed document sent back to the site. 
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x phone call with the patient, asking for email confirmation to corroborate verbal 
consent. 
x organize a conference call or video call together with the patient and impartial 
witness, where needed. 
x if no phone call or video call is possible, email documented consent. 
Depending on regional requirements the options can be limited, after consultation with the 
relevant IRB/IEC and/or regulatory authority. 
Data collected during a telephone assessment visit can be entered into the e-CRF pages of the 
corresponding “missed” visit. Enter the date of the phone call as the “date of visit” and enter the 
data obtained in the applicable CRF pages. For the assessments that are not performed, answer 
“no” to the question if the assessment was made in the respective forms. Add “COVID-19 
telephone” in the comment section of the CRF. 
If you are not able to contact the patient, inactivate the full study visit in the CRF and confirm 
the missing visit in the comments section as “COVID-19.” 
Other than conducting telephone assessments, there may be other changes in the current practice 
on site. Halting spirometry in COVID-19 patients may be required, or only allowing use of a 
dedicated spirometry device (for contamination reasons).  There can be a temporary halt in 
performing this assessment, or conducting a partial assessment is also permitted. 
In order to give a clear overview of protocol deviations related to the specific COVID-19 
situation, dedicated protocol deviations with the COVID-19 label have been created to which any 
missed visit or assessment can be attributed. 
 
5. APPENDIX 9. 
6. Patients with known hepatitis B virus (HBV), hepatitis C virus (HCV) or human 
immunodeficiency virus (HIV) seropositivity. 
7. Patients with known autoimmune disease other than MG (for example 
autoimmune thyroiditis, rheumatoid arthritis…) that would interfere with an 
accurate assessment of clinical symptoms. 
8. Patients with clinical evidence of other significant disease or patients who 
underwent a recent major surgery, which could confound the results of the trial or 
put the patient at undue risk. Patients with renal/hepatic function impairment can 
be included. 
9. Patients with known medical history of hypersensitivity to any of the ingredients 
of efgartigimod or placebo. 
4.4. 
Early Discontinuation 
The criteria for roll-over into this trial (see Section 4.3) are to be followed explicitly. If it is noted 
that a patient who does not meet 1 or more of the inclusion and/or meets 1 or more of the 
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exclusion criteria is inadvertently rolled over, the Medical Monitor at sponsor’s designated CRO 
and the sponsor’s Medical Director must be contacted immediately. 
Early discontinuation from the trial is defined as the permanent cessation of further participation 
in the trial prior to its planned completion.  
Patients must be discontinued early from the trial if: 
x They withdraw their consent. 
x The investigator, after discussion with the sponsor’s Medical Director, deems it is in 
the patient’s best interest. 
x Patient is pregnant. 
x Patient receives rescue therapy (Part A only). 
x Patient develops an SAE that is likely to result in a life-threatening situation or pose a 
serious safety risk to the patient. 
x Prohibited medication is taken (Part A only) (see Section 6.8.1). 
Patients might discontinue early from the trial if: 
x Patient has clinical evidence of bacterial, viral or fungal disease or any other 
significant disease which could confound the results of the trial or put the patient at 
undue risk. In this situation, decision on whether or not to discontinue patients early 
from trial will depend on the evaluation on a case-by-case basis. Patients who, after 
evaluation of the above situations are not discontinued from the trial, may have a 
temporary interruption from trial treatment (see Section 4.4.1). 
For patients who discontinue early from trial, the assessments will depend on the visit at which it 
was decided that the patient had to discontinue (see Section 5.4, Figure 1, and Figure 2).  
Patients who discontinue early from the trial within a treatment period should perform the 
planned assessments of the corresponding treatment period visit. These patients will not receive 
any further administration of efgartigimod during the trial and will return for the ED visit 1 
month (30 ± 2 days) after the last dose administration. An unscheduled visit can be organized if 
deemed necessary by the investigator. 
Patients who discontinue early from the trial between the last visit of a treatment period (TPnV4 
or TPEnV4) and the next intertreatment period visit (ITPnVn or ITPEnVn) should perform the ED 
assessments 1 month (30 ± 2 days) after the last dose administration. 
Patients who discontinue early from the trial at the ITP (Part A) or ITPE (Part B) visit should 
perform the ED assessments, instead of the ITPnVn (Part A) or ITPEnVn (Part B) assessments. 
Patients who discontinue early from the trial after the ITP (Part A) or ITPE (Part B) visit should 
perform the ED assessments. 
Any patient prematurely discontinuing the trial during Part A should perform the EoA/ED 
assessments according to the General Schedule of Assessments for Part A (Table 1). Any patient 
prematurely discontinuing the trial during Part B should perform the EoS/ED assessments 
according to the General Schedule of Assessments for Part B (Table 2). 
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All patients are free to withdraw consent from participation in the trial at any time, for any 
reason, specified or unspecified, and without prejudice to further treatment. Prior to actual 
withdrawal of consent, an effort should be made to perform a final set of assessments as per the 
EoA/ED visit in the General Schedule of Assessments for Part A (Table 1) or the EoS/ED visit in 
the General Schedule of Assessments for Part B (Table 2). Investigators will make and document 
all efforts made to contact those patients who do not return for scheduled visits. 
Before enrolling in ARGX-113-2002 from Part B, patients must first complete the early 
discontinuation (ED) visit assessments specified in Table 2. The previous efgartigimod IV dose 
must have been received at least 30 days before entry into ARGX-113-2002. Patients who enroll 
in ARGX-113-2002 will not return to ARGX-113-1705. 
The reason for early discontinuation from the trial must be documented by the investigator on the 
appropriate page of the eCRF. 
4.4.1. 
Temporary Interruption From Trial Treatment 
A patient who does not need to be discontinued early from the trial might still have a temporary 
interruption from trial treatment. A temporary interruption from trial treatment is defined as a 
discontinuation only from the current treatment period, but the patient might still be eligible for 
further additional treatments with efgartigimod within this trial.  
Patients for whom treatment is interrupted will have to complete the current treatment period and 
will continue the trial as per the General Schedule of Assessments for Part A (Table 1) or for 
Part B (Table 2). A patient who has had a temporary interruption of trial treatment in Part A may 
also continue into Part B of the trial and receive (re-)treatment if the conditions mentioned above 
are met. 
4.4.2. 
Missed Doses 
Patients who miss 1, 2, or 3 infusions per treatment period will stay in the trial and will follow 
the assessments as per the General Schedule of Assessments for Part A (Table 1) or for Part B 
(Table 2). These patients may be eligible for further treatment periods during the trial. A patient 
who has missed doses in Part A may also continue into Part B of the trial and receive 
(re-)treatment if the conditions in Section 4.4.1 are met. 
4.5. 
Protocol Deviations 
The investigator should not implement any deviation from, or changes of the protocol without 
agreement by the sponsor and prior review and documented approval from the Institutional 
Review Board/Independent Ethics Committee (IRB/IEC) of an amendment from the IRB/IEC 
and Regulatory Authority as per local regulation, except where necessary to eliminate an 
immediate hazard to trial patients, or when the change involves only logistical or administrative 
aspects of the trial (eg, change of telephone numbers, …). The investigator (or delegate) should 
document and explain any deviation from the approved protocol. 
Planned protocol exemptions or waivers will not be approved by the sponsor. 
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4.6. 
Early Termination of Trial or Site 
The trial may be terminated at any time by the sponsor for safety concerns due to SAEs, inability 
to achieve the recruitment target within reasonable time or if in the sponsor's judgment, there are 
no further benefits to be expected from the trial. In such a case, the sponsor or delegate will 
inform the trial investigators, institutions, and all regulatory authorities. 
The trial can also be terminated by the Regulatory Authority for any reason or if recommended 
by the DSMB, or at a site level by the IRB/IEC. The sponsor may close individual trial sites 
prematurely for reasons such as poor protocol compliance or unsatisfactory recruitment of 
patients. 
4.7. 
End of Trial Definition 
The end of trial is defined as last patient last visit. 
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5. 
TRIAL PROCEDURES 
Every effort should be made to ensure that the protocol-required tests and procedures are 
completed as described. When a protocol-required procedure cannot be performed, the 
investigator will document the reason and any corrective and preventive actions that he/she has 
taken to ensure that the normal processes are adhered to in source documents. The trial team 
should be informed of these incidents in a timely manner. 
Patients should be seen for all visits on the designated days or as closely as possible to the 
original planned visit schedule. There is a permissible window of ±1 day for treatment period 
visits (visit 1 to visit 4), of ±2 days for ITPnVn (Part A), and of ±7 days for the ITPEnVn 
(Part B), EoA visit (day 365) and the EoS visit (day 1095 or when efgartigimod becomes 
commercially available or another option to access efgartigimod is available, whichever option 
comes first). Every effort should be made to schedule every visit on the exact day (which is 
relative to the baseline visit [SEB, TPnB or TPEnB]) within the window as described in the 
General Schedule of Assessments for Part A (Table 1) and for Part B (Table 2). 
Each treatment period consists of 4 weekly infusions over a period of 3 weeks. 
The SEB will be set at the first trial visit, while the baseline of each subsequent treatment period 
(TPnB or TPEnB) will be set at visit 1 of each corresponding treatment period. 
At all visits, assessments of disease severity should be performed first, before any other trial-
specific assessments, with the only exception of obtaining informed consent at SEB and the 
weight assessment. The MG-ADL scale needs to be performed prior to the QMG scale (Part A) 
as per Table 1. Acetylcholinesterase inhibitors must be halted for at least 12 hours before the 
QMG assessment (Part A). 
As from signature of informed consent until last study visit, all AEs that occur and all 
concomitant medications, whether allowed or not, that are taken during the trial are to be 
recorded on the appropriate pages in the electronic case report form (eCRF). 
5.1. 
Informed Consent and Roll-Over Visit 
The roll-over visit (SEB) can be either ITP0V1 or TP1V1, depending on the patient status 
regarding the need for (re-)treatment upon roll-over from trial ARGX-113-1704. The first visit in 
trial ARGX-113-1705 will always coincide with the last visit in trial ARGX-113-1704.  
The patient must sign the informed consent form (ICF) prior to any trial-related assessment. The 
assessments done for the last visit in trial ARGX-113-1704 should not be repeated. 
Prior to signing the ICF, trial patients will be instructed not to participate in any other clinical 
trial that involves an intervention or collection of data until the completion of the current trial. 
After informed consent has been obtained, participants of trial ARGX-113-1704 will be screened 
at the site for eligibility to roll over to this trial based on the inclusion and exclusion criteria 
defined in Sections 4.3.1 and 4.3.2, respectively. 
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In addition to obtaining written informed consent and the eligibility check, the following 
assessments will be performed at SEB: 
x Clinically relevant medical and surgical history, clinically relevant prior treatments 
and all concomitant medications (see Sections 6.8 and 7.2.5) 
x Demographic characteristics (date of birth, sex, race, and ethnicity, per national 
regulations) 
x Assessments of disease severity – the MG-ADL scale should be administered before 
the QMG scale  
x Suicidal ideation and behavior will be assessed via a targeted question based on the 
Patient Health Questionnaire item 9 (PHQ-9)17 
x Complete physical examination, including at a minimum: general appearance, skin, 
lymph nodes, musculoskeletal/extremities, abdomen, cardiovascular, respiratory, and 
neurological systems 
x Weight and height 
x Vital signs (supine blood pressure, heart rate, body temperature). It is recommended 
that the method used to measure body temperature at SEB is maintained throughout 
the trial for each patient 
x ECG (heart rate, PR, QT, and QRS interval) 
x Clinical laboratory tests (see Appendix 3 for an overview of the clinical laboratory 
tests that will be assessed). Patients need to have fasted at least 8 hours prior to 
sampling 
x Urinalysis 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS) 
x Pharmacodynamic biomarkers (anti-AChR antibodies in AChR-Ab seropositive 
patients only, total IgG and subtypes [IgG1, IgG2, IgG3 and IgG4], and anti-MuSK 
antibodies in MuSK-Ab seropositive patients only). Information on the AChR/MuSK-
Ab serotype (seronegative or seropositive) is available from trial ARGX-113-1704 
x Anti-drug antibodies (ADA) 
x Assess AEs, if any 
5.2. 
Treatment Period 
5.2.1. 
Treatment Period Part A 
A treatment period will include assessments in 4 weekly visits including treatment with 
efgartigimod in eligible patients in need for (re-)treatment. A new treatment period can only be 
started if it can be completed within the 1-year duration of Part A of the trial (re-treatment in 
Part A can start at the latest on day 336). Otherwise, the patient can be transitioned to Part B 
after completing the EoA visit assessments (Table 1). These assessments should be completed 
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even if the patient is unwilling or unable to continue to Part B, then he/she should continue to the 
EoA visit.  
The following assessments will be performed from visit 1 to visit 4 of each treatment period: 
x Assessments of disease severity – the MG-ADL scale should be administered before 
the QMG scale* 
x Suicidality assessment* 
x Physical examination* 
x Weight will only be measured in case there is an obvious weight change compared to 
the last weight assessment* 
x Vital signs* 
x ECG, only at visit 1 and visit 4 of each treatment period* 
x Clinical laboratory tests. Patients need to have fasted at least 8 hours prior to 
sampling* 
x Urinalysis* 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS)* 
x Pharmacodynamic biomarkers (anti-AChR antibodies in AChR-Ab seropositive 
patients only, total IgG and subtypes [IgG1, IgG2, IgG3 and IgG4], and anti-MuSK 
antibodies in MuSK-Ab seropositive patients only)* 
x ADA, only at visit 1 and visit 4 of each treatment period* 
x Administration of efgartigimod as an IV infusion over a period of 1 hour. Patients 
will remain at the site for at least 1 hour following the end of the infusion for safety 
monitoring, based on the patient’s clinical status 
x Review of concomitant medication and rescue therapy 
x Assess AEs, if any 
*These assessments should be performed prior to administration of efgartigimod (predose). 
At visit 1 of each subsequent treatment period, the conditions for (re-)treatment will be checked 
before administration of efgartigimod (see Section 4.1). 
Patients may not receive (re-)treatment with efgartigimod if, at the time of (re-)treatment, they 
have clinical evidence of bacterial, viral or fungal disease, or any other significant disease which 
could confound the results of the trial or put patients at undue risk. Patients who are in need of an 
additional treatment but who are not eligible to receive (re-)treatment for reasons listed here will 
remain in the trial to receive appropriate alternative MG treatment. 
Patients who fail to respond to efgartigimod for 3 consecutive treatment periods will be 
discontinued from the trial. Treatment failure means the absence of a decrease of at least 2 points 
in total MG-ADL score compared to the corresponding TPnB in at least 50% of the assessments 
(ie, TPnV2, TPnV3, TPnV4 and the first posttreatment period visit).  
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If a patient becomes eligible for (re-)treatment with efgartigimod by meeting the criteria for the 
total MG-ADL score as stated in Section 4.1, but cannot complete the entire treatment period 
during Part A (ie, after day 336) then the patient can be transitioned to Part B after completing 
the EoA visit assessments in Table 1. These assessments should be completed even if the patient 
is unwilling or unable to continue to Part B (see Section 5.1). 
The transition to Part B can be either ITPE0Vn or TPE1V1, depending on the patient status 
regarding the need for (re-)treatment upon transition from Part A. The first visit in Part B will 
always coincide with the EoA visit in Part A. The assessments done for the last visit in Part A 
should not be repeated in Part B. 
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment 
of the SoC dose and/or frequency) is not allowed from trial entry until 1 week after the last 
infusion of the first Treatment Period, and from the first infusion until 1 week after the last 
infusion of each subsequent Treatment Period. 
From 1 week after the last infusion of each Treatment Period up to and prior to the 
administration of the first infusion of the next Treatment Period, a dose reduction in SoC 
consistent with current medical practice is allowed. 
5.2.2. 
Treatment Period Part B 
A Treatment Period will include assessments in 4 weekly visits including treatment with 
efgartigimod in eligible patients in need for (re-)treatment. A new Treatment Period can only be 
started if it can be completed within the trial duration (up to maximum 3 years or until 
efgartigimod becomes commercially available or another option to access efgartigimod is 
available, whichever option comes first). 
The following assessments will be performed from visit 1 to visit 4 of each Treatment Period: 
x Assessments of disease severity (MG-ADL scale)* 
x Weight will be measured at visit 1 and when there is an obvious weight change 
compared to the last weight assessment* 
x Vital signs* 
x ECG, only at visit 1 and visit 4 of each Treatment Period* 
x Clinical laboratory tests (local labs), only at visit 1 and visit 4 of each Treatment 
Period.* 
x Urinalysis, only at visit 1 and visit 4 of each Treatment Period* 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS), only at visit 1 and visit 4 of each Treatment Period* 
x ADA, only at visit 1 of each Treatment Period* 
x Administration of efgartigimod as an IV infusion over a period of 1 hour. Patients 
will remain at the site for at least 1 hour following the end of the infusion for safety 
monitoring, based on the patient’s clinical status 
x Review of concomitant medication 
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x Assess AEs if any 
*These assessments should be performed prior to administration of efgartigimod (predose). 
At visit 1 of each Treatment Period, the conditions for (re-)treatment will be checked before 
administration of efgartigimod (see Section 4.1). 
Patients may not receive (re-)treatment with efgartigimod if, at the time of (re-)treatment, they 
have clinical evidence of bacterial, viral or fungal disease, or any other significant disease which 
could confound the results of the trial or put patients at undue risk. 
If a patient becomes eligible for (re-)treatment with efgartigimod but cannot complete the entire 
Treatment Period within duration of the trial, the patient should continue to the EoS visit. 
If the investigator considers that the patient will not have a clinical benefit from re-treatment 
then the patient cannot start a new Treatment Period. The patient should then continue to the EoS 
visit. 
A change of the type or dose/regimen of SoC (replacing, adding or removing SoC, or adjustment 
of the SoC dose and/or frequency) is allowed, without restrictions, following current medical 
practice. 
5.3. 
Intertreatment Period 
Intertreatment period visits occur every 30 days after the previous visit in Part A and every 
90 days after the previous visit in Part B. 
At each ITPnVn (Part A) or ITPEnVn (Part B) an evaluation of the need for (re-)treatment should 
be done. In case the patient is not in need of (re-)treatment, assessments for ITPnVn (Part A) or 
ITPEnVn (Part B) should be performed as listed below and per the General Schedule of 
Assessments for Part A (Table 1) or for Part B (Table 2). However, in case the evaluation shows 
that the patient is in need of (re-)treatment and is also eligible for (re-)treatment, the assessments 
according to TPnV1 (Part A) or TPEnV1 (Part B) are to be performed instead (see Section 5.2). If 
an ITP visit for Part A is scheduled within 14 days of the EoA visit, then the EoA visit should be 
performed instead. 
The following assessments will be performed in Part A: 
x Assessments of disease severity – the MG-ADL scale should be administered before 
the QMG scale 
x Suicidality assessment 
x Physical examination 
x Weight will only be measured in case there is an obvious weight change compared to 
the last weight assessment 
x Vital signs 
x ECG 
x Clinical laboratory tests. Patients need to be fasted at least 8 hours prior to sampling 
x Urinalysis 
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x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS) 
x Pharmacodynamic biomarkers (anti-AChR antibodies in AChR-Ab seropositive 
patients only, total IgG and subtypes [IgG1, IgG2, IgG3 and IgG4], and anti-MuSK 
antibodies in MuSK-Ab seropositive patients only) 
x Review of concomitant medication and rescue therapy 
x Assess AEs, if any 
The following assessments will be performed in Part B: 
x Assessments of disease severity (MG-ADL scale) 
x Vital signs 
x ECG 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS) 
x Review of concomitant medication 
x Assess AEs, if any 
5.4. 
End of Part A, End of Study, and Early Discontinuation Visit 
In case of early discontinuation, the same assessments as scheduled for EoA (day 365) or EoS 
(day 1095 or when efgartigimod becomes commercially available or another option to access 
efgartigimod is available, whichever option comes first) must be performed as follows: 
For EoA/ED (Part A): 
x Assessments of disease severity – the MG-ADL scale should be administered before 
the QMG scale and before any other assessments except for weight 
x Suicidality assessment 
x Physical examination 
x Weight 
x Vital signs 
x ECG 
x Clinical laboratory tests – Patients should have fasted at least 8 hours before sampling 
x Urinalysis 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS) 
x Pharmacodynamic biomarkers (anti-AChR antibodies in AChR-Ab seropositive 
patients only, total IgG and subtypes [IgG1, IgG2, IgG3, and IgG4], and anti-MuSK 
antibodies in MuSK-Ab seropositive patients only) 
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x ADA 
x Review of concomitant medication and rescue therapy 
x Assess AEs if any 
For EoS/ED (Part B): 
x Before enrolling in ARGX-113-2002 from Part B, patients must first complete the 
early discontinuation (ED) visit assessments specified in Table 2. The previous 
efgartigimod IV dose must have been received at least 30 days before entry into 
ARGX-113-2002. Patients who enroll in ARGX-113-2002 will not return to ARGX-
113-1705 
x Assessments of disease severity (MG-ADL scale) should be administered before any 
other assessments except weight 
x Physical examination 
x Weight 
x Vital signs 
x ECG 
x Clinical laboratory tests (local labs) 
x Urinalysis 
x Urine pregnancy test (only for women of childbearing potential, see DEFINITION 
OF TERMS) 
x ADA (only in case of ED) 
x Review of concomitant medication 
x Assess AEs, if any 
5.5. 
Unscheduled Visit 
It is at the investigator’s discretion or at patient’s request to initiate an unscheduled (UNS) visit, 
if deemed necessary for the patient’s safety and well-being. All such visits will be documented in 
the eCRF with any additional required documentation based on the nature of UNS visit. 
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to those individuals authorized to dispense efgartigimod, and maintained within the appropriate 
temperature ranges. efgartigimod must be stored as specified at delivery and in the original 
packaging. 
Efgartigimod must be stored refrigerated (2-8°C or 35-46°F) in their secondary packaging, 
should not be exposed to freezing temperatures, should not be shaken and should be protected 
from direct sunlight during storage at the clinical site. 
Further requirements on temperature logging during storage and information on how to handle 
temperature excursions can be found in the IMP management manual (pharmacy manual). 
6.5. 
Method of Assigning Patients to Treatment Group 
Not applicable. 
6.6. 
Timing of Dose for Each Patient 
Only to patients who need (re-)treatment, efgartigimod will be administered IV over a period of 
1 hour as 4 weekly infusions at visits 1, 2, 3, and 4 of each Treatment Period, provided they are 
eligible. Patients will be asked to remain at the site for a minimum of 1 hour after the end of 
infusion as part of routine safety monitoring at visits 1, 2, 3, and 4 of each Treatment Period. 
6.7. 
Blinding 
This is an open-label trial with a single treatment group; no blinding will be applied. 
6.8. 
Prior Treatments and Concomitant Medications 
Clinically relevant prior treatments received by the patient including (1) previous MG treatments 
(including SoC) with patient’s response and reason for changing treatment/dose in the last 
12 months and (2) non-MG treatment in the last 6 months, prior to Screening in trial 
ARGX-113-1704. Information should include start and stop dates and tick box for those 
continuing as concomitant medication. 
Vaccines (except for live/live-attenuated vaccines) will be allowed during the trial when 
administered at least 48 hours pre-infusion or 48 hours post-infusion of IMP. 
Any vaccination received within 28 days of screening up until 28 days after the final dose of the 
IMP should be recorded in the eCRF with the brand name of the vaccine and the date of vaccine 
administration. 
All concomitant medications whether allowed or not must be recorded in the eCRF. 
6.8.1. 
Prohibited Medications During the Trial 
The following medications or treatments will lead to discontinuation from treatment during 
Part A of the trial as from SEB onwards: 
x Any IgG therapy 
x A change in the type or an increase of the dose/frequency of SoC, even if used for 
indications other than MG 
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x Any monoclonal antibody for immunomodulation 
x Live/live-attenuated vaccines 
x Rescue therapy when used in patients who meet the criteria to be rescued 
x Use of PLEX or immunoadsorption more than once during study period 
In Part B of the trial, a change of the type or dose/regimen of SoC (replacing, adding or 
removing SoC, or adjustment of the SoC dose and/or frequency) is allowed without restrictions, 
following standard clinical practice. 
PLEX, IVIg, immunoadsorption or use of a new type of corticosteroid or an increased dose of 
the current corticosteroids used as stand-alone therapy or in combination is also allowed in Part 
B. 
6.8.2. 
Rescue Therapy (Part A only) 
Rescue therapy is permitted for patients experiencing protocol-defined MG clinical deterioration 
AND if in addition the treating physician believes that the patient’s health is in jeopardy if rescue 
therapy is not given. An MG clinical deterioration permitting rescue therapy to be given is 
defined as a patient experiencing at least 1 of the following: (1) new or worsening of respiratory / 
bulbar symptoms or (2) at least 2-point increase of individual non-ocular MG-ADL items. 
Rescue therapy will be limited to PLEX, IVIg, immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current corticosteroids used as stand-alone therapy or 
in combination. The type of rescue therapy used should be documented. 
In case a patient needs rescue therapy according to the treating investigator, the Medical Director 
at the sponsor should be informed in addition to the Medical Monitor at the sponsor’s designated 
CRO; whenever possible prior to actual implementation of the rescue therapy. 
In situations where the treatments as listed above are given under the protocol-defined rescue 
criteria, patients will be discontinued early from the trial. 
6.9. 
Medical Care of Patients After End of Study 
After a patient has completed the trial, or has withdrawn/discontinued early, usual treatment will 
be administered, if required, in accordance with the trial site’s SoC and generally accepted 
medical practice depending on the patient’s individual needs. The sponsor will not provide any 
additional care to these patients.  
6.10. 
Treatment Compliance 
The investigator should promote treatment compliance by stating that compliance is necessary 
for the patient’s safety and the validity of the trial. The prescribed dose, timing, and mode of 
administration may not be changed. All dates and start and end time of efgartigimod 
administration and any deviations from the intended regimen must be recorded. 
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6.11. 
Handling Missed Doses of Investigational Medicinal Product 
Patients in need for (re-)treatment will receive 4 weekly IV infusions of efgartigimod at a dose of 
10 mg/kg over a period of 1 hour during each Treatment Period, provided they are eligible. 
All efforts will be done to ensure that the patient receives the 4 administrations of efgartigimod 
within the allowed time windows. However, if a patient misses 1 or more doses in any Treatment 
Period, the patient will not be discontinued from the trial or from further trial treatment and will 
complete all further visits and assessments according to the General Schedule of Assessments for 
Part A (Table 1) and for Part B (Table 2). This patient may be eligible for further Treatment 
Periods during the trial. 
In case a dose needs to be delayed for more than 3 days, the dosing should be skipped to ensure 2 
consecutive doses are given with an interval of at least 3 days. 
6.12. 
Accountability of Investigational Medicinal Product 
Detailed instructions on accountability of efgartigimod will be included in the IMP management 
manual (pharmacy manual). 
6.13. 
Storage of Blood Samples in the Trial 
Any remaining samples after the analysis per protocol has been completed may be stored for up 
to 15 years for future additional research to address any scientific questions related to 
efgartigimod or MG, unless this would not be allowed according to local regulations or the 
patient would not agree. 
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7. 
TRIAL ASSESSMENTS 
7.1. 
Monitoring of Disease Severity 
Monitoring of disease severity will be assessed using MG-ADL (Part A and B) and QMG 
(Part A only). The assessments, where applicable, have to be performed predose on all 
efgartigimod infusion days and prior to any other assessment at each visit, except for the 
assessment of weight (if applicable) and signing of the ICF at SEB. The MG-ADL scale needs to 
be performed prior to the QMG scale in Part A (Table 1). 
Monitoring of disease severity for a given patient is preferentially assessed, whenever possible, 
by 1 and the same trained evaluator throughout the course of the trial. 
7.1.1. 
Myasthenia Gravis Activities of Daily Living 
The MG-ADL is an 8-item patient-reported scale (Appendix 1) to assess MG symptoms and their 
effects on daily activities. It evaluates the capacity to perform different activities of daily living 
such as talking, chewing, swallowing, breathing, brushing the teeth/combing the hair, or rising 
from a chair and it also assesses double vision and eyelid droop. It is a discrete quantitative 
variable in which the 8 items are rated from 0 to 3 and the total score can point from 0 to 24, 
with higher total scores indicating more impairment. The assessments to be performed using 
MG-ADL (Appendix 1) do not require any equipment to assess MG symptoms and their effects 
on daily activities. The scoring of MG-ADL should be performed by a trained and certified 
evaluator. 
7.1.2. 
Quantitative Myasthenia Gravis 
The QMG quantifies disease severity based on impairments of body functions and structures as 
defined by the International Classification of Functioning, Disability and Health.18  
The QMG consists of 13 items (Appendix 2) that assess ocular, bulbar, and limb function. Out of 
the 13 items, 6 are timed tests of endurance measured in seconds. Each item has a possible score 
from 0-3. The total possible score is 39, where higher total scores indicate more severe 
impairments. It is based on quantitative testing of specific muscle groups to assess limb function. 
It requires minimal equipment such as spirometer, mouthpieces that fit the spirometer, nose clips, 
stopwatch, cups and water for swallowing tests, goniometer, dynamometer, and is based on the 
trained rater’s examination. The scoring of QMG should be performed by a trained evaluator. 
7.2. 
Safety 
Safety assessments will consist of monitoring and recording all AEs, pregnancies, suicidality 
assessment (Part A only), safety laboratory testing, measurement of vital signs, ECGs, physical 
examinations; and other tests that are deemed critical to the safety evaluation of the trial in all 
patients who receive at least 1 dose of efgartigimod. As discussed in Section 7.2.1.5, any 
pregnancy that occurs while a patient is enrolled into the trial will also be monitored and reported 
according to the appropriate regulations. 
The DSMB will evaluate the safety data periodically (see Section 7.2.6). 
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7.2.1. 
Adverse Events 
The investigator is responsible for recording all AEs observed during the trial from the time the 
patient signs the ICF until the last contact of the patient. 
Definition of AE: An AE is any untoward medical occurrence in a clinical trial patient whether 
or not a pharmaceutical product is administered, and which does not necessarily have a causal 
relationship with this treatment. An AE can therefore be any unfavorable and unintended sign 
(including an abnormal laboratory finding), symptom, or disease temporally associated with the 
use of a medicinal product or efgartigimod, whether or not considered related to the medicinal 
product or efgartigimod. 
An AE can also be a new disease or exacerbation of an existing disease (a worsening in the 
character, frequency, or severity of a known condition), if considered clinically relevant by the 
investigator. 
Abnormal laboratory values, or test results, physical examination findings, and other abnormal 
investigational findings (ie, ECG) should not be reported as AEs unless they are considered 
clinically significant, eg, require therapy (eg, hematologic abnormality that requires transfusion 
or hematological stem cell support) or lead to treatment discontinuation. 
Death is not considered an AE but an outcome. 
MG disease worsening, if considered clinically relevant by the investigator, can be reported as 
AE, provided that it is supported by a clinically relevant change in total MG-ADL score (as 
compared to SEB). The investigator should contact the sponsor in case of clinically relevant 
worsening of the disease. 
Adverse Drug Reaction (ADR): Any untoward and unintended response in a patient to 
efgartigimod, which is related to any dose administered to that patient. 
Definition of Serious AE (SAE): An SAE, experience or reaction, is any untoward medical 
occurrence (whether considered to be related to efgartigimod or not) that at any dose: 
x Results in death 
x Is life-threatening (the patient is at a risk of death at the time of the event; it does not 
refer to an event, which hypothetically might have caused death if it was more severe) 
x Requires inpatient hospitalization or prolongation of existing hospitalization. 
However, a planned hospitalization related to the administration of efgartigimod is 
not considered an SAE 
(Hospital admissions and/or surgical operations planned before a trial are not 
considered SAEs or if the illness or disease, which caused hospitalization, existed 
before the patient was enrolled in the trial, provided that it did not deteriorate in an 
unexpected way during the trial. However, the condition for which the surgery is 
required may be an AE.) 
x Results in persistent or significant disability or incapacity, OR 
x Is a congenital abnormality or birth defect 
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x Other: Medically significant events, which do not meet any of the criteria above, but 
may jeopardize the patient and may require medical or surgical intervention to 
prevent 1 of the other serious outcomes listed in the definition above. Examples of 
such events are blood dyscrasias (eg, neutropenia or anemia requiring blood 
transfusion, etc.) or convulsions that do not result in inpatient hospitalization 
Suspected Unexpected Serious Adverse Reactions (SUSARs) and Unexpected Adverse 
Reactions: Any suspected adverse reaction that is serious, unexpected, and considered to be 
related to drug exposure is defined as a SUSAR. 
An unexpected AE is any adverse drug event, which is not listed in the current IB or is not listed 
at the specificity or intensity that has been observed. 
Suspected adverse reaction means any AE for which there is a reasonable possibility that the 
drug caused the AE. 
An untoward and unintended post-dosing response to a non-trial drug is, by definition, not a 
SUSAR, but is, however, an AE. 
Each AE is to be evaluated for duration, severity, seriousness and causal relationship to 
efgartigimod or trial procedures. The action taken with the investigational drug and the outcome 
of the event must also be recorded. 
Treatment-emergent adverse event (TEAE): Any AE temporally associated with the use of 
efgartigimod, whether considered related to efgartigimod or not. TEAEs are recorded from the 
start of efgartigimod administration, until completion of the patient’s last visit. 
Overdose 
For the purposes of this trial, exceeding the dosage requirements specified in this protocol (see 
Section 6.1) represents an overdose. In case of suspected overdose, the patient should be treated 
according to standard medical practice based on the investigator’s judgment. 
Severity 
All AEs observed will be graded using the National Cancer Institute (NCI) Common 
Terminology Criteria for Adverse Events (CTCAE) version 5.0. The NCI-CTCAE is a 
descriptive terminology, which can be utilized for AE reporting. A grading (severity) scale is 
provided for each AE term. Grade refers to the severity of the AE. If a particular AE’s severity is 
not specifically graded by the guidance document, the investigator is to use the general NCI-
CTCAE definitions of Grade 1 through Grade 5 following his or her best medical judgment. The 
CTCAE displays Grades 1 through 5 with unique clinical descriptions of severity for each AE 
based on the following general guideline: 
x Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations 
only; intervention not indicated. 
x Grade 2: Moderate; minimal, local or non-invasive intervention indicated; limiting 
age--appropriate instrumental activities of daily living (ADL). 
x Grade 3: Severe or medically significant but not immediately life-threatening; 
hospitalization or prolongation of hospitalization indicated; disabling; limiting 
self-care ADL. 
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x Grade 4: Life-threatening consequences; urgent intervention indicated. 
x Grade 5: Death related to AE. 
Relationship 
The causal relationship between efgartigimod/trial procedures and the AE has to be characterized 
as unrelated, unlikely, related, possible, and probable. 
x Events can be classified as “unrelated” if there is not a reasonable possibility that 
efgartigimod caused the AE. 
x An “unlikely” relationship suggests that only a remote connection exists between 
efgartigimod and the reported AE. Other conditions, including chronic illness, 
progression or expression of the disease state, or reaction to concomitant medication, 
appear to explain the reported AE. 
x A “related” relationship suggests that the AE follows a reasonable temporal sequence 
from administration of efgartigimod, it follows a known or expected response pattern 
to efgartigimod and it cannot reasonably be explained by known characteristics of 
patient’s clinical state. 
x A “possible” relationship suggests that the association of the AE with efgartigimod is 
unknown; however, the AE is not reasonably supported by other conditions. 
x A “probable” relationship suggests that a reasonable temporal sequence of the AE 
with drug administration exists and, in the investigator’s clinical judgment, it is likely 
that a causal relationship exists between the drug administration and the AE, and 
other conditions (concurrent illness, progression or expression of disease state, or 
concomitant medication reactions) do not appear to explain the AE. 
In final evaluation for reporting, the relationship will be converted into “Binary Determination” 
as per Council for International Organizations of Medical Sciences (CIOMS). Unrelated and 
Unlikely will be clubbed into “Unrelated” and Related, Possible and Probable will be clubbed 
into “Related” for final reporting purpose. 
7.2.1.1. 
Adverse Events of Special Interest 
An AESI (serious or non-serious, related or not related) is an event of scientific and medical 
concern specific to the sponsor’s product or program. 
Efgartigimod treatment induces reductions in IgG levels, and there is a potential risk for 
infections associated with the low IgG levels. As such, any infection will be considered AESI in 
this trial. Further characterizing information will be collected in the eCRF, such as: location of 
infection, relationship to underlying condition, medical history and concomitant medication, 
reoccurrence of previous infection, previous rescue therapy, any confirmatory procedure, culture 
or urgent medical intervention. 
7.2.1.2. 
Reporting of Adverse Events and Serious Adverse Events 
All AEs that occur during the trial from signature of the ICF until the last study visit are to be 
recorded on the appropriate AE pages (either “serious” or “non-serious”) in the eCRF. The 
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investigator should complete all the details requested, including dates of onset, time of onset, 
stop date (when applicable), stop time (when applicable), severity, action taken, outcome, and 
relationship to efgartigimod, and to trial procedures. Each event should be recorded separately in 
the eCRF. 
All AEs spontaneously reported by the patient or reported in response to the open question from 
the trial personnel: “Have you had any health problems since the previous visit or since you were 
last asked?,” or revealed by observation will be collected and recorded in the eCRF. When 
collecting AEs, the recording of diagnoses is preferred (when possible) to recording a list of 
signs and symptoms. However, if a diagnosis is known and there are other signs or symptoms 
that are not generally part of the diagnosis, the diagnosis and each sign or symptom will be 
recorded separately. 
Any SAE, including death due to any cause, which occurs during this trial after signature of the 
ICF, whether or not related to efgartigimod, must be reported immediately (within 24 hours of 
the trial site’s knowledge of the event). All SAEs will be recorded (within 24 hours) on the paper 
SAE Report Form and the AE form in the eCRF, the investigator or delegated site staff should 
check that all entered data are consistent. An alert email for the SAE report in the eCRF will then 
automatically be sent by email to the sponsor’s designated CRO safety mailbox via the electronic 
data capture (EDC) system. The paper SAE Report Form should be faxed or emailed to the 
sponsor’s designated CRO (see the Safety Mailbox/Fax details on the title page of this protocol). 
The report will contain as much available information concerning the SAE to enable the sponsor 
(or an authorized representative) to file a report, which satisfies regulatory reporting 
requirements. These timelines apply to initial reports of SAEs and to all follow-up reports. 
Criteria for documenting the relationship to efgartigimod, as well as severity, outcome, and 
action taken will be the same as those previously described. 
The investigator shall report within 24 hours any SAE (s)he becomes aware of after a patient’s 
last visit if a causal relationship with the investigational product is suspected. Such a serious 
adverse reaction (SAR) is to be collected and reported as previously described for SAEs. 
All SAEs that are spontaneously reported within 30 days after the last trial visit are to be 
collected and reported as previously described and all efforts should be made to follow-up until 
resolution. 
Additional follow-up information should be completed and entered on a paper SAE Report Form 
and sent by fax/email to the sponsor’s designated CRO. 
7.2.1.3. 
Reporting of Serious Adverse Events to Regulatory Authorities and 
Investigators 
The sponsor’s designee will be responsible for reporting all SUSARs, the Analysis of Similar 
Events (AOSE), and any other applicable reports to regulatory authorities, ethics committees, 
and investigators, in accordance with national regulations in the countries where the trial is 
conducted. Relative to the first awareness of the event by/or further provision to the sponsor’s 
designee, SUSARs will be submitted within 7 days for fatal and life-threatening events and 
15 days for other SUSARs, unless otherwise required by national regulations. The sponsor’s 
designee will also prepare an expedited report for other safety issues where applicable. 
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The investigational site will also forward a copy of all expedited reports to his or her IEC/IRB in 
accordance with national regulations. 
7.2.1.4. 
Follow-up of Adverse Events and Serious Adverse Events 
Any AEs observed from signing the ICF to the last study visit will be followed up to resolution, 
until the patient is lost to follow-up, or until the patient withdraws consent. Resolution means 
that the patient has returned to a baseline state of health or the investigator does not expect any 
further improvement or worsening of the AE. 
Every effort should be made to follow all (S)AEs considered to be related to efgartigimod or trial 
procedures until an outcome can be reported. If the patient is lost to follow-up, all AEs will be 
categorized based on the investigator’s last assessment. 
All SAEs that are spontaneously reported after the last study visit are to be collected and reported 
as previously described (as per Section 7.2.1.2) and will be followed up. During the trial period, 
resolution of SAEs (with dates) should be documented on the SAE page of the eCRF and in the 
patient’s medical record to facilitate source data verification. If, after follow-up, return to the 
baseline status or stabilization cannot be established, an explanation should be recorded on the 
SAE page of the eCRF. 
All pregnancies reported during the trial should be followed until pregnancy outcome. 
For SAEs, non-serious AEs, and pregnancies, the sponsor’s designee may follow-up by 
telephone, fax, electronic mail, and/or a monitoring visit to obtain additional case details and 
outcome information (eg, from hospital discharge summaries, consultant reports, or autopsy 
reports) in order to perform an independent medical assessment of the reported case. 
7.2.1.5. 
Reporting and Follow-up Requirements for Pregnancies 
7.2.1.5.1. Pregnancies in Female Patients 
Urine pregnancy tests will be conducted and analyzed locally at visits as detailed in the General 
Schedule of Assessments for Part A (Table 1) and for Part B (Table 2). Results will be recorded 
in the eCRF. 
If a patient becomes pregnant after the administration of efgartigimod and up to 90 days after the 
patient received the last infusion, the sponsor and/or sponsor’s designee should be informed 
immediately (ie, within 24 hours of the trial site’s knowledge of the event). The following 
actions will be performed: 
x The patient should immediately be discontinued from trial treatment. 
x The patient should have the planned ED assessments.  
x All planned assessments (see Sections 4.4 and 5.4) must be performed unless 
contraindicated by pregnancy (harmful to fetus) or unless the patient withdraws 
informed consent.  
The investigator must update the patient with information currently known about potential risks 
and about available treatment alternatives. The pregnancy should be followed up to determine 
outcome, including spontaneous or voluntary termination, details of the birth, and the presence or 
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absence of any birth defects, congenital abnormalities, or maternal and/or newborn 
complications. 
If required by local regulations, the female participant will be requested to sign a separate 
pregnancy ICF. Full details will be recorded on a paper Pregnancy Report Form and submitted 
via email or fax (see the Safety Mailbox/Fax details on the title page of this protocol), and 
reporting details will be specified in the trial manual. The investigator will update the Pregnancy 
Report Form with additional information as soon as the outcome of the pregnancy is known. 
If the outcome of the pregnancy is an SAE, then this must be additionally reported as an SAE on 
the appropriate SAE Report Form. 
7.2.1.5.2. Pregnancies in Female Partners of Male Patients 
Male patients will be instructed through the ICF to immediately inform the investigator if their 
partner becomes pregnant during the trial or up to 90 days after they received the last infusion of 
efgartigimod. A Pregnancy Report Form should be completed by the investigator within 24 hours 
after learning of the pregnancy and submitted via email or fax (see the Safety Mailbox/Fax 
details on the title page of this protocol). Attempts should be made to collect and report details of 
the course and outcome of any pregnancy in the partner of a male patient exposed to 
efgartigimod. 
The pregnant partner will need to sign an ICF to allow for follow-up on her pregnancy. Once the 
ICF has been signed, the investigator will update the Pregnancy Report Form with additional 
information on the course and outcome of the pregnancy. An investigator who is contacted by 
the male patient or his pregnant partner may provide information on the risks of the pregnancy 
and the possible effects on the fetus, to support an informed decision in cooperation with the 
treating physician and/or obstetrician. 
7.2.2. 
Clinical Laboratory Evaluations 
In Part A, blood and urine samples for determination of clinical chemistry, hematology and 
urinalysis will be analyzed at a central laboratory. PD and ADA will be analyzed at a specialty 
laboratory as indicated in the General Schedule of Assessments for Part A (Table 1) and 
Appendix 3. Patients need to be fasting for at least 8 hours prior to the sampling for clinical 
laboratory tests as from SEB up to EoA. 
In Part B, blood and urine samples for determination of clinical chemistry, hematology and 
urinalysis will be analyzed at local laboratories and results will not be recorded in the eCRF. 
Blood samples for ADA will be analyzed at a specialty laboratory as indicated in the General 
Schedule of Assessments for Part B (Table 2) and Appendix 3.  
Additional safety samples may be collected if clinically indicated at the discretion of the 
investigator. 
For all patients of childbearing potential, a urine pregnancy test will be conducted and analyzed 
locally at the site (on the urine samples taken for urinalysis, if applicable) at all visits in Part  A 
(Table 1) and at visit 1 and 4 of each Treatment Period, at ITPE visits, at EoS/ED and at the 
discretion of the investigator in Part B (Table 2). 
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The estimated total maximum blood volume needed for a patient during Part A of the trial (when 
completing the trial up until the last visit) is between 170 mL for a patient who receives 
1 Treatment Period only and 362 mL for a patient who receives a maximum of 6 Treatment 
Periods. The estimated total maximum blood volume needed for a patient during Part B of the 
trial (when completing the trial up until the last visit) is between 24 mL for a patient who 
receives 1 Treatment Period only and 100 mL for a patient who receives 6 Treatment Periods. 
Clinical laboratory tests will be reviewed for results of potential clinical significance at all time 
points throughout the trial. The investigator will evaluate any change in laboratory values. If the 
investigator determines a laboratory abnormality to be clinically significant, it will be considered 
as a laboratory AE; however, if the abnormal laboratory value is consistent with a current 
diagnosis, it may be documented accordingly without being reported as an AE. 
The details of sampling, handling, storage, and transportation of the samples will be described in 
the laboratory manual. The actual sample collection date and time must be entered in the 
patient’s source documents and on the central lab assessment eCRF page. 
Refer to Appendix 4 for the addresses of the laboratories used for sample analyses and storage. 
7.2.3. 
Vital Signs, Physical Examination, and ECG 
Assessment of vital signs (supine blood pressure, heart rate, and body temperature), physical 
examination and ECG will be performed at the time points indicated in the General Schedule of 
Assessments for Part A (Table 1) and for Part B (Table 2) (predose at dosing days). 
Supine blood pressure and heart rate will be measured using standard equipment after 10 minutes 
rest on a bed. 
It is recommended that the method used to measure body temperature at SEB is maintained 
throughout the trial for each patient. 
A physical examination will include at a minimum an assessment of general appearance, skin, 
lymph nodes, musculoskeletal/extremities, abdomen, cardiovascular, respiratory, and 
neurological system.  
Weight will be measured at SEB, at the EoA/ED visit, at visit 1 of Part B, at the EoS/ED visit, 
and can be repeated at any visit when there is an obvious weight change compared to the last 
weight assessment. Patients will be required to remove their shoes and wear light indoor clothing 
for this measurement. 
A 12-lead ECG will be recorded locally as per local regulations in the supine position after the 
patient has rested in this position for at least 10 minutes. The assessments on heart rate, PR, QT 
and QRS intervals will be read centrally. 
7.2.4. 
Suicidality Assessment 
As is recommended for trials involving a biological product for a neurological indication, a 
prospective assessment for suicidal ideation and behavior will be included in this clinical trial 
(Part A only). 
This so-called suicidality assessment will be conducted by specifically asking the following 
question, derived from the PHQ-9: 
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x "Over the last 2 weeks, how often have you been bothered by thoughts that you 
would be better off dead, or of hurting yourself in some way?" 
The patient will be asked this question at each visit and the response documented. Response 
options as per the PHQ-9 are limited to the following: "not at all," "several days," "more than 
half the days" or "nearly every day." 
This specific question was selected for the reported significant linear relationship between the 
item 9 score of the PHQ-9 and the risk of subsequent suicide attempt.17 
7.2.5. 
Medical and Surgical History 
Clinically significant findings and pre-existing conditions present in a patient prior to SEB must 
be reported on the relevant medical history/current medical conditions page of the eCRF. 
Information should be provided on medical and surgical history, and concomitant medical 
conditions specifying those ongoing at SEB. 
7.2.6. 
Data Safety Monitoring Board (DSMB) 
The sponsor will appoint a DSMB consisting of an independent group of clinical experts, who 
are not participating in the trial. They will be supplemented by an independent statistician. The 
objective of the DSMB will be to review all safety data (including the overall number of patients 
treated up to that point, rates, and patient-level details). Fixed meetings will be scheduled based 
on the recruitment rate into the trial, and incidence of (S)AEs. In addition, ad hoc meetings can 
be requested at any time during the trial by either the sponsor or the DMSB. The DSMB will 
advise the sponsor concerning continuation, modification or termination of the trial after every 
meeting. 
The composition, objectives, and role and responsibilities of the independent DSMB will be 
described in a DSMB charter, agreed with the DSMB members and sponsor. The DSMB charter 
will also define and document the content of the safety summaries, and general procedures 
(including communications). 
7.2.7. 
Visit Reminder/Subject ID Card 
Patients must be provided with the address and telephone number of the main contact for 
information about the clinical trial. The investigator must therefore provide a “Visit 
Reminder/Subject ID Card” to each patient. In an emergency situation this card serves to inform 
the responsible attending physician that the patient is in a clinical trial and that relevant 
information may be obtained by contacting the investigator. Patients must be instructed to keep 
the card in their possession at all times. 
7.3. 
Pharmacodynamics 
In Part A, the PD markers (total IgG and IgG subtypes [IgG1, IgG2, IgG3 and IgG4], and 
autoantibodies [anti-AChR antibodies for the AChR-Ab seropositive patients and anti-MuSK 
antibodies for the MuSK-Ab seropositive patients]) will be measured at the time points as 
indicated in Table 1. Information on the AChR/MuSK-Ab serotype is available from trial 
ARGX-113-1704. 
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These PD markers will be determined using validated assays. The actual date and time of 
collection of the blood sample will be recorded in the relevant section of the eCRF. 
7.4. 
Anti-Drug Antibodies 
Blood samples to assess ADA will be collected predose at the time points as indicated in Table 1 
and Table 2. At baseline (SEB, TPnB, and TPEnB), confirmatory and titer analysis will be 
performed using a validated ADA assay. Samples having a positive ADA titer will be further 
investigated in a neutralizing ADA assay. The actual date and time of collection of the blood 
sample will be recorded in the relevant section of the eCRF. 
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8. 
STATISTICS 
The statistical analyses will be performed by sponsor’s designated CRO using statistical analysis 
systems SAS® (SAS Institute, Cary, NC, United States [US]) version 9.2 or higher, and the 
software package R, if applicable. The standard operating procedures (SOPs) and work 
instructions of sponsor’s designated CRO will be used as the default methodology if not 
otherwise specified. 
Any change to the data analysis methods described underneath will be mentioned in the 
statistical analysis plan (SAP). Any additional analysis, and the justification for making the 
change, will be described in the Clinical Trial Report (CTR). Additional exploratory analyses of 
the data will be conducted as deemed appropriate. 
Due to the single-arm, open-label nature of the design, evaluation of all endpoints will be 
essentially descriptive. Endpoints will be summarized by treatment (as received in ARGX-113-
1704). 
8.1. 
Determination of Sample Size 
Not applicable. 
8.2. 
Analysis Populations 
The analysis population will consist of all patients who rolled over from trial ARGX-113-1704. 
8.3. 
Patient Disposition, Characteristics and Concomitant Medication 
A tabular presentation of the patient disposition will be provided. It will include the number of 
patients enrolled, completed (by cycle), as well as the number of early discontinuations 
(including rescued patients), with reasons for discontinuation from trial treatment or trial and 
major protocol deviations. 
A listing will be presented to describe dates of SEB, completion or early discontinuation and the 
reason for early discontinuation, if applicable, for each patient. 
Patient characteristics will be recorded prior to enrollment and will be listed and summarized. 
Overall summaries will include descriptive statistics for continuous measures (number of 
observations, mean, standard deviation, median, minimum and maximum) and for categorical 
measures (sample size, frequency, and percent). Patient characteristics include but are not limited 
to age, sex, race, weight, and body mass index (BMI). 
Use of concomitant medication will be summarized with frequency and percentage. All 
concomitant medications used will be listed.  
8.4. 
Statistical Methods 
8.4.1. 
Primary and Secondary Endpoint Analyses 
All endpoints will be summarized in all enrolled patients and by means of descriptive statistics.  
Frequency tables will be made for all binary variables, ie, AEs, by cycle and overall.  
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Summary statistics will be provided for the continuous endpoints (eg, laboratory values, vital 
signs, ECGs) in terms of absolute values and changes from TP1B by cycle and available time 
points.  
8.4.2. 
Tertiary Endpoint Analyses 
The tertiary endpoints will be summarized descriptively.  
Summary statistics will be provided for the continuous endpoints (eg, total MD-ADL score, total 
QMG score, levels of total IgG and subtypes, anti-AChR/anti-MuSK antibodies) in terms of 
absolute values, changes from TP1B or changes from TPnB, by cycle and available time points. 
For levels of total IgG and subtypes and also anti-AChR/anti-MuSK antibodies, the percentage 
change from TP1B and from TPnB will also be presented. 
Frequency tables will be made for incidence and prevalence of ADA to efgartigimod. 
8.5. 
Interim Analyses 
Interim analyses might be performed to support questions for authorities and/or submissions. 
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9. 
QUALITY CONTROL AND QUALITY ASSURANCE 
9.1. 
Investigator’s Responsibility 
The investigator will comply with the protocol (which has been approved/given favorable 
opinion by the Ethics Committee), ICH GCP, and applicable regulatory requirements. The 
investigator is ultimately responsible for the conduct of all aspects of the trial at the trial site and 
verifies by signature the integrity of all data transmitted to the sponsor. The term “investigator” 
as used in this protocol as well as in other trial documents, refers to the investigator or authorized 
trial personnel that the investigator has designated to perform certain duties. Sub-investigators or 
other authorized trial personnel are eligible to sign for the investigator, except where the 
investigator’s signature is specifically required. 
9.2. 
Quality Control of Data 
Quality control will be applied to each stage of data handling. 
The following steps will be taken to ensure the accuracy, consistency, completeness, and 
reliability of the data: 
x Investigator meetings 
x Central laboratories for clinical laboratory parameters and ECGs 
x Site initiation visit 
x Routine site monitoring 
x Ongoing site communication and training 
x Ongoing oversight by Clinical Trial Monitors of safety parameters and adherence to 
selection criteria 
x Data management quality control checks 
x Continuous data acquisition and cleaning 
x Quality control check of the CTR 
x To avoid inter-observer variability, every effort should be made to ensure that the 
same individual who made the initial baseline determinations completes all safety and 
disease severity evaluations. 
In addition, sponsor and/or sponsor’s designated CRO Clinical Quality Assurance (CQA) 
Department may conduct periodic audits of the trial processes, including, but not limited to trial 
site, or site visits, central laboratories, vendors, clinical database, and final CTR. When audits are 
conducted, access must be authorized for all trial-related documents including medical history 
and concomitant medication documentation to authorized sponsor’s representatives and 
regulatory authorities. 
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9.3. 
Monitoring 
The sponsor has engaged the services of a CRO to perform all clinical trial monitoring functions 
within this clinical trial. Sponsor’s designated CRO monitors will work in accordance with SOPs 
of the CRO.  
Monitoring visits must be conducted according to the applicable ICH GCP guidelines to verify 
that, among others, the: 
x Data are authentic, accurate, and complete. 
x Safety and rights of patients are being protected. 
x Trial is conducted in accordance with the currently approved protocol, any other trial 
agreements and all applicable regulatory requirements. 
The investigator and the head of the medical institution (where applicable) agrees to allow the 
Clinical Trial Monitor direct access to all relevant documents. 
The investigator must ensure provision of reasonable time, space and qualified personnel for 
monitoring visits. 
The Clinical Trial Monitor will perform an eCRF review and Source Document Verification 
(SDV).  
The Source Documentation Agreement Form describes the source data for the different data in 
the eCRF. This document should be completed and signed by the Clinical Trial Monitor and 
investigator and should be filed in the investigator’s trial file. Any data item for which the eCRF 
will serve as the source must be identified, agreed and documented in the Source Documentation 
Agreement Form. 
Upon completion or premature discontinuation from the trial, the Clinical Trial Monitor will 
conduct site closure activities with the investigator and site staff as appropriate, in accordance 
with applicable regulations, ICH GCP guidelines and CRO/sponsor procedures. 
Monitoring details describing strategy (eg, risk-based initiatives in operations and quality such as 
Risk Management and Mitigation Strategies and Analytical Risk-Based Monitoring), methods, 
responsibilities and requirements, including handling of noncompliance issues and monitoring 
techniques (central, remote, or on-site monitoring) are provided in the monitoring plan. 
9.4. 
Data Management 
Data generated within this clinical trial will be handled according to the SOPs of the Data 
Management and Biostatistics departments of the sponsor’s designated CRO. 
Case report forms are provided for each patient in electronic format. It will be transcribed by the 
trial site staff from the source documents onto the eCRF. Date must be entered in English and 
guidelines for eCRF completion, including the collection of investigator’s e-signature, will be 
provided by the CRO. Appropriate training and security measures will be completed with the 
investigator and all authorized trial site staff prior to the trial being initiated and any data being 
entered into the system for any trial patient at the site. 
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The eCRF is essentially considered a data entry form and should not constitute the original (or 
source) medical records unless otherwise specified. Source documents are all documents used by 
the investigator or hospital that relate to the patient’s medical history, that verify the existence of 
the patient, the inclusion and exclusion criteria, and all records covering the patient’s 
participation in the trial. They can include laboratory notes, ECG results, memoranda, pharmacy 
dispensing records, patient files, etc. The eCRFs should be completed by the investigator or a 
qualified designee from the site as soon as the data are available. 
As a matter of regulation, the investigator is responsible for the accuracy and authenticity of all 
clinical data entered onto eCRFs. Prior to database lock, each completed eCRF must be reviewed 
for accuracy by the investigator, corrected as necessary and then approved. The investigator’s 
e-signature serves to attest that the information contained on the eCRFs has been reviewed by the 
investigator and is true and accurate. The investigator will be required to electronically sign off 
the eCRF. 
The data will be verified for missing data, inconsistencies, and for necessary medical 
clarifications. Queries arising from these checks will be flagged to the trial site, and the trial site 
staff will correct data, confirm or clarify data as appropriate. The CRO will provide the details of 
the review process in a data management plan and monitoring plan. Any change, including the 
issuing of queries, will be fully audit trailed by the EDC application, meaning the name of the 
person, time, and date stamp are recorded, as well as the reason for change. 
Data will also be provided by third party vendors, such as the results generated by the central 
labs, the Interactive Response Technology (IRT) provider, or centralized ECG reading. These 
data will need to be reconciled with the data recorded in the eCRF before it can be merged with 
the eCRF data into the clinical database. The CRO will provide a data management plan 
detailing this reconciliation. 
Adverse events, concomitant diseases/medical history terms will be assigned to a lowest level 
term (LLT) and a preferred term (PT) and will be classified by high level term (HLT), high level 
group term, and primary system organ class (SOC) according to the Medical Dictionary for 
Regulatory Activities (MedDRA) thesaurus. 
Prior and concomitant medications will be classified according to active drug substance using the 
World Health Organization Drug Dictionary (WHO-DD). The generic name, the preferred name, 
and the WHO name will be assigned using WHO-DD thesaurus. 
The Anatomical Therapeutic Chemical (ATC) classes will be assigned to the prior and 
concomitant medications. 
9.5. 
Quality Assurance Audit 
Trial sites, the trial database and trial documentation may be subject to Quality Assurance audit 
during the course of the trial by the sponsor or sponsor’s designee (CRO or other vendor) on 
behalf of sponsor. In addition, inspections may be conducted by regulatory bodies at their 
discretion. 
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10. 
ETHICS 
10.1. 
Institutional Review Board or Independent Ethics Committee 
The investigator will provide the sponsor or designee with documentation of IRB/IEC approval 
of the protocol and informed consent documents before the trial may begin at the trial sites. The 
investigator will supply documentation to the sponsor or designee of the required IRB/IEC’s 
annual renewal of the protocol, and any approvals of revisions to the informed consent document 
or amendments to the protocol. 
The investigator will report promptly to the IRB/IEC, any new information that may adversely 
affect the safety of patients or the conduct of the trial. Similarly, the investigator will submit 
written summaries of the trial status to the IRB/IEC annually, or more frequently if requested by 
the IRB/IEC. Upon completion of the trial, the investigator will provide the IRB/IEC with a brief 
report of the outcome of the trial, if required. 
10.2. 
Ethical Conduct of the Trial 
This trial will be conducted, and the informed consent will be obtained, according to the ethical 
principles stated in the Declaration of Helsinki (2013), the applicable guidelines for GCP, or the 
applicable drug and data protection laws and regulations of the countries where the trial will be 
conducted. 
To comply with the Declaration of Helsinki (2013), argenx is assessing the appropriateness and 
possibility of making the study drug available for clinical study participants post-trial. 
10.3. 
Patient Information and Informed Consent 
The ICF, will be used to explain the risks and benefits of trial participation to the patient in 
simple terms before the patient rolled over into the trial. A separate ICF will be given in case of 
pregnancy of a female partner of male patient. The ICF contains a statement that the consent is 
freely given, that the patient is aware of the risks and benefits of entering the trial, and that the 
patient is free to withdraw from the trial at any time. Written consent must be given by the 
patient and/or legally acceptable representative, after the receipt of detailed information on the 
trial. 
All ICFs must be available in the local and vernacular languages required at the site and include 
patient information sheets/brochures that outline the trial procedures. All ICF(s) must be signed 
and dated by the patient or a legally acceptable representative. 
For patients who are unable to read and write, the patient information sheet and ICF(s) should be 
read to the patient in his/her native language in the presence of a legally acceptable 
representative who is literate and not affiliated with the trial. The patient having understood the 
information given to him/her in the presence of a legally acceptable representative will 
thumbprint the ICF(s) and the same will be countersigned by the legally acceptable 
representative. If the patient or legally acceptable representative cannot read, then an impartial 
witness will witness and attest the entire consent process and will be required to sign the ICF. 
Confirmation of a patient’s informed consent must also be documented in the patient’s medical 
record prior to any testing under this protocol, including SEB tests and assessments. 
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The investigator is responsible for ensuring that informed consent is obtained from each patient 
or legally acceptable representative and for obtaining the appropriate signatures and dates on the 
informed consent document prior to the performance of any protocol procedures and prior to the 
administration of efgartigimod. The investigator will provide each patient with a copy of the 
signed and dated ICF(s). 
10.4. 
Patient Data Protection 
The ICF will incorporate (or, in some cases, be accompanied by a separate document 
incorporating) wording that complies with relevant data protection and privacy legislation. 
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11. 
TRIAL ADMINISTRATION 
11.1. 
Data Handling and Record Keeping 
It is the investigator’s responsibility to maintain essential trial documents (including records and 
documents pertaining to the conduct of this trial and the distribution of IMP, regulatory 
documents, eCRFs, signed patient ICFs, laboratory test results, IMP inventory records, source 
documents, relevant correspondence, AE reports, and all other supporting documentation) as 
required by the applicable national regulatory requirements. The trial site should plan on 
retaining such documents for approximately 25 years after trial completion. The trial site should 
retain such documents until at least 2 years after the last approval of a marketing application in 
an ICH region and until there are no pending or contemplated marketing applications in an ICH 
region or at least 2 years after the formal discontinuation of clinical development of 
efgartigimod. The sponsor will notify the principal investigator of these events. 
These documents should be retained for a longer period if required by the applicable regulatory 
requirements or the hospital, institution, or private practice in which the trial is being conducted. 
Patient identification codes (patient names and corresponding trial numbers) will be retained for 
this same period of time. These documents may be transferred to another responsible party, 
acceptable to sponsor, who agrees to abide by the retention policies. The investigator is required 
to notify the sponsor (or an authorized representative) in writing prior to changing the location or 
status of any essential clinical trial documents. The investigator must contact sponsor prior to 
disposing of any trial records. 
No records should be disposed of without the written approval of argenx BVBA. 
For trials conducted outside the US under a US investigational new drug (IND), the principal 
investigator must comply with US FDA IND regulations and with those of the relevant national 
and local health authorities. 
11.2. 
Direct Access to Source Data/Documents 
The sponsor or designee and auditor may access patient records for the purpose of monitoring 
this trial, auditing, and managing progress details. The investigator must be fully aware that the 
sponsor or designee and auditor can inspect or verify documents to verify patient chart and eCRF 
records. Such information must be kept confidential and must have locked facilities that allow 
for this. The investigator will prepare and maintain adequate and accurate source documents to 
record all observations and other pertinent data for each patient enrolled into the trial. 
The investigator is responsible for maintaining source documents. These will be made available 
for inspection by the Clinical Trial Monitor at each monitoring visit. The investigator must 
submit a completed eCRF for each patient who receives efgartigimod, regardless of duration. All 
supportive documentation submitted with the eCRF, such as laboratory or hospital records, 
should be clearly identified with the trial and patient number. Any personal information, 
including patient name, should be removed or rendered illegible to preserve individual 
confidentiality. 
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11.3. 
Investigator Information 
11.3.1. 
Investigator Obligations 
The investigator is responsible for ensuring that all trial site personnel, including sub-
investigators, adhere to all applicable regulations and guidelines, including local laws and 
regulations, regarding the trial, both during and after trial completion. The investigator is 
responsible for informing the IRB/IEC of the progress of the trial and for obtaining annual 
IRB/IEC renewal. The investigator is responsible for informing the IRB/IEC of completion of 
the trial and will provide the IRB/IEC with a summary of the results of the trial. 
11.3.2. 
Protocol Signatures 
After reading the protocol, each investigator will sign the protocol signature page and send a 
copy of the signed page to the sponsor or representative. By signing the protocol, the investigator 
confirms in writing that he/she has read, understands, and will strictly adhere to the trial protocol 
and will conduct the trial in accordance with ICH Tripartite Guidelines for GCP and applicable 
regulatory requirements. The trial will not be able to start at any site where the investigator has 
not signed the protocol. 
11.3.3. 
Publication Policy 
All information regarding efgartigimod supplied by the sponsor to the investigator and all data 
generated as a result of this trial, are considered confidential and remain the sole property of the 
sponsor. The results of the trial will be reported in a CTR. 
The CTR written in accordance with the ICH E3 Guideline, will be submitted in accordance with 
local regulations. 
Any manuscript, abstract or other publication or presentation of results or information arising in 
connection with the trial must be prepared in conjunction with the sponsor and must be 
submitted to the sponsor for review and comment prior to submission for publication or 
presentation. Trial patient identifiers will not be used in publication of results. 
Authorship will be granted based on scientific input, recruitment efforts, and will be granted 
upon decision of a publication committee. This committee will include among others the 
coordinating investigator and the sponsor. 
The sponsor will register and/or disclose the existence of and the results of clinical trials as 
required by law. 
11.3.4. 
Financing and Insurance 
The sponsor will fund the trial as outlined in the Clinical Trial Agreement.  
The sponsor will obtain adequate global/local insurance for the trial participants including the 
trial patients for the required duration of time. 
The sponsor maintains an insurance coverage for this trial in accordance with the laws and 
regulations of the countries in which the trial is performed. Liability and insurance provisions for 
this trial are specified in the investigator’s contract. The terms and conditions will apply as 
specified in the policy document. 
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12. 
REFERENCES 
1. Howard JF Jr, Barohn RJ, Cutter GR, et al. A randomized, double-blind, placebo-
controlled phase II study of eculizumab in patients with refractory generalized myasthenia 
gravis. Muscle Nerve. 2013;48(1):76-84. 
2. Gilhus NE, Verschuuren JJ. Myasthenia gravis: subgroup classification and therapeutic 
strategies. Lancet Neurol. 2015;14(10):1023-1036. 
3. Gilhus NE. Myasthenia gravis. N Engl J Med. 2016;375(26):2570-2581. 
4. Vincent A, Lang B, Kleopa KA. Autoimmune channelopathies and related neurological 
disorders. Neuron. 2006;52(1):123-138. 
5. Kaminski HJ. Seronegative myasthenia gravis—a vanishing disorder? JAMA. Neurol 
2016;73(9):1055-1056. 
6. Roopenian DC, Akilesh S. FcRn: the neonatal Fc receptor comes of age. Nat Rev 
Immunol. 2007;7(9):715-725. 
7. Challa DK, Velmurugan R, Ober RJ, et al. FcRn: from molecular interactions to 
regulation of IgG pharmacokinetics and functions. Curr Top Microbiol Immunol. 
2014;382:249-272. 
8. Vaccaro C, Zhou J, Ober RJ, et al. Engineering the Fc region of immunoglobulin G to 
modulate in vivo antibody levels. Nat Biotech. 2005;23(10):1283-1288. 
9. Patel DA, Puig-Canto A, Challa DK, et al. Neonatal Fc receptor blockade by Fc 
engineering ameliorates arthritis in a murine model. J Immunol. 2011;187(2):1015-1022. 
10. Challa DK, Bussmeyer U, Khan T, et al. Autoantibody depletion ameliorates disease in 
murine experimental autoimmune encephalomyelitis. MAbs. 2013:5(5): 655-659. 
11. Nowak RJ, Dicapua DB, Zebardast N, et al. Response of patients with refractory 
myasthenia gravis to rituximab: a retrospective study. Ther Adv Neurol Disord. 
2011;4(5):259-266. 
12. Howard JF Jr, Utsugisawa K, Benatar M, et al. Safety and efficacy of eculizumab in anti-
acetylcholine receptor antibody-positive refractory generalised myasthenia gravis 
(REGAIN): a phase 3, randomised, double-blind, placebo-controlled, multicentre study. 
Lancet Neurol. 2017;16(12):976-986. 
13. Meriggioli MN, Sanders DB. Autoimmune myasthenia gravis: emerging clinical and 
biological heterogeneity. Lancet Neurol. 2009;8(5):475-490. 
14. Liu JF, Wang WX, Xue J, et al. Comparing the autoantibody levels and clinical efficacy 
of double filtration plasmapheresis, immunoadsorption, and intravenous immunoglobulin 
for the treatment of late-onset myasthenia gravis. Ther Apher Dial. 2010;14(2):153-160. 
15. Drachman DB. Myasthenia gravis. N Engl J Med. 1994;330(25):1797-1810. 
16. Wolfe GI, Kaminski HJ, Aban IB, et al. Randomized trial of thymectomy in myasthenia 
gravis. N Engl J Med. 2016;375(6): 511-522. 
17. Simon GE, Rutter CM, Peterson D, et al. Does response on the PHQ-9 Depression 
Questionnaire predict subsequent suicide  attempt or suicide death? Psychiatr Serv. 
2013;64(12): 1195-1202. 
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18. World Health Organization. International Classification of Functioning, Disability, and 
Health (ICF). 1st edition. World Health Organization website 2001. Available at 
http://www.who.int/classifications/icf/en/. 
19. Wolfe GI, Herbelin L, Nations SP, et al. Myasthenia gravis activities of daily living 
profile. Neurology. 1999;52(7):1487-1489. 
20. Muppidi S, Wolfe GI, Conaway M, et al. MG-ADL: still a relevant outcome measure. 
Muscle Nerve. 2011;44(5):727-731. 
21. Barohn RJ, McIntire D, Herbelin L, et al. Reliability testing of the quantitative myasthenia 
gravis score. Ann N Y Acad Sci. 1998:841:769-772. 
22. Katzberg HD, Barnett C, Merkies IS, et al. Minimal clinically important difference in 
myasthenia gravis: outcomes from a randomized trial. Muscle Nerve. 2014;49(5):661-665. 
 
6\VWHP 9HUVLRQ  6WDWXV $SSURYHG 'RFXPHQW ,' 9970)

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13. 
APPENDICES 
APPENDIX 1: Myasthenia Gravis Activities of Daily Living 
 
Source: website MGFA, MG-ADL19,20 
 
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APPENDIX 2: Quantitative Myasthenia Gravis Score 
 
Source: website MGFA, Quantitative MG score21,22  
 
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APPENDIX 3: Laboratory Evaluations 
Hematology 
Hemoglobin, platelet count, white blood cell (WBC) count with WBC 
differential 
Clinical Chemistry 
Creatinine, creatinine clearance, blood urea nitrogen (BUN), glucose, 
glycosylated hemoglobin [HbA1c], alanine aminotransferase (ALT), 
aspartate aminotransferase (AST), total bilirubin, gamma-glutamyl 
transferase (GGT), C-reactive protein (CRP), alkaline phosphatase 
(ALP), lactate dehydrogenase (LDH), uric acid, albumin, potassium, 
sodium, calcium, lipid panel (total cholesterol, high density lipoprotein 
[HDL], low density lipoprotein [LDL], and triglycerides), international 
normalized ratio (INR) and activated partial thromboplastin time (aPTT) 
Urinalysis 
Color, clarity/appearance, specific gravity, pH, protein, glucose, ketones, 
blood, bilirubin, urobilinogen, nitrite, leukocyte esterase, and 
microscopic examination including red blood cell (RBC) count, WBC, 
cast crystals, bacteria. 
Other 
Urine human chorionic gonadotrophin (ß-HCG) 
Pharmacodynamic (PD) 
markers 
Total IgG and subtypes (IgG1, IgG2, IgG3, and IgG4), and AChR-Ab 
(binding) levels in AChR-Ab seropositive patients only and anti-muscle-
specific kinase (MuSK) antibodies in MuSK-Ab seropositive patients 
only. Information on the AChR/MuSK-Ab serotype (seronegative or 
seropositive) is available from trial ARGX-113-1704. 
Anti-drug antibodies 
(ADA) 
Levels of anti-efgartigimod binding and neutralizing antibodies (if 
applicable) 
Note: For Part A, all blood and urine samples will be collected locally (predose on dosing days) and analyzed at a 
central or specialty laboratory. For Part B, blood and urine samples for clinical chemistry, hematology, and 
urinalysis will be analyzed locally, while ADA samples will be analyzed at a specialty laboratory. 
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APPENDIX 4: Administrative Structure 
Clinical Laboratories (Part A only) 
United States 
Covance  
8211 SciCor Drive  
Indianapolis, IN 46214 
United States 
Europe 
Covance  
Rue Moise-Marcinhes 7 
CH – 1217 Meyrin  
Geneva 
Switzerland 
Japan 
Covance Japan Co., Ltd. 
Harumi Triton Square Office Tower Y  
8F,1-8-11, Harumi, Chuo-ku, 
Tokyo 104-6108  
Japan 
 
 
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Analysis of Pharmacodynamics (PD), Anti-Drug Antibodies (ADA) 
France 
SGS France 
90 Avenue des Hauts de la Chaume BP. 28 
86281 Saint-Benoît Cedex 
France 
Long-Term Storage of Pharmacodynamics (PD), Anti-Drug Antibodies (ADA) 
Germany 
Brooks Life Science, BioStorage Technologies GmbH 
Im Leuschnerpark 1b 
64347 Griesheim 
Germany 
Study Monitoring/Medical Monitoring 
United States 
Syneos Health™ group company 
including INC Research, LLC, together with INC Research 
UK Limited 
3201 Beechleaf Court, Suite 600 
Raleigh, North Carolina 27604-1547 
United States  
Phone +1 919-876-9300 
Germany 
EastHORN Clinical Service GmbH 
Im Mediapark 6c 
50670 Cologne 
Germany 
Clinical Trial Supply Management 
Belgium 
CSM  
Watson & Crick Hill 
Rue Granbonpré 11 
B-1435 Mont-Saint-Guibert 
Belgium 
Data Management and Biostatistics 
Belgium 
SGS Life Sciences (SGS LS), a division of SGS Belgium 
NV 
Generaal de Wittelaan 19A b5 
BE – 2800 – Mechelen 
Belgium 
Drug-Safety Reporting 
United States 
Parexel International  
8 Federal Street 
Billerica MA 01821 
United States 
 
 
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APPENDIX 7: Summary of Changes From Prior Amendments 
Protocol Version 3.1 compared to Protocol Version 3.2 
Changes from Protocol Version 3.1 compared to Protocol Version 3.2 are summarized below. 
Of note: updates of headers/footers and tables of contents as well as editorial changes regarding 
layout, font, and format are not recorded in this summary. 
Section 
Change 
Rationale 
Table 2  General 
Schedule of 
Assessments for 
Part B 
 
Assessments highlighted in yellow indicate 
assessments … 
changed to 
Assessments highlighted by use of bold italics indicate 
assessments … 
Correction 
Appendix 8 
Guidance to Sites in 
Case of Suspected 
COVID-19 in Patients 
1. Does the patient have symptoms such as cough, 
fever, muscle pain, shortness of breath? 
- If NO: Go to Questions 2 and 3. 
- If YES: 
• If the patient is not tested for COVID-19:  
The visit will take place after at least 14 days post first 
symptoms and only if the patient is symptom free… 
… 
• If the patient is tested and found to be COVID-19 
positive:  
The patient can only come to the site once he/she is 
symptom free, and so … 
changed to 
1. Does the patient have symptoms, such as cough, 
fever, muscle pain, shortness of breath*? 
- If NO: Go to Questions 2 and 3. 
- If YES: 
• The patient should be tested for COVID-19:  
The Investigator needs to document a positive COVID-
19 test as an AESI. The anonymized result needs to be 
sent to the sponsor for filing. If COVID-19 safety 
measures are stopped according to local regulations, 
COVID-19 tests should continue to be performed and 
the results sent to the sponsor. 
*Shortness of breath includes an otherwise unexplained 
deterioration in the patient’s MG-ADL score for 
breathing. In cases where the MG-ADL score for 
breathing is 2 or 3 additional COVID-19 testing should 
Changes have been made to 
allow for COVID-19 testing 
of patients exhibiting 
symptoms of the disease. 
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Section 
Change 
Rationale 
be carried out. The exception to this is when a patient 
has an MG-ADL score for breathing of 2 at baseline. In 
such cases the patient should only be tested when the 
MG-ADL score for breathing returns to 2 after 
previous improvement or when it deteriorates to 3. 
The visit will only take place once the patient has a 
negative test for COVID-19… 
… 
• If the patient is tested and found to be COVID-19 
positive:  
The patient can only come to the site once he/she has a 
negative test for COVID-19, and so … 
 
As the COVID-19 pandemic poses issues for both sites and patients and presents unprecedented 
challenges in uncharted territory, this crisis prompted the sponsor to perform a critical review of 
both efgartigimod administration and changes needed to the study in order to safeguard patient 
safety, while still being able to gather additional data. 
Therefore, for the global amendment of the ARGX-113-1705 protocol from version 3.0 to 3.1 an 
addendum has been added to the study detailing the safety measures and changes to be 
implemented in the current situation. The risk/benefit, safety profile, guidance for site conduct 
and potential changes in the Schedule of Assessments are detailed in Appendix 8. 
This will be a temporary change to the procedures of the study and will only last as long as the 
COVID-19 pandemic affects the ability of the patients to attend their study visits. 
Protocol Version 3.0 compared to Protocol Version 3.1 
Changes from Protocol Version 3.0 compared to Protocol Version 3.1 are summarized below. 
Of note: updates of headers/footers and tables of contents as well as editorial changes regarding 
layout, font, and format are not recorded in this summary. 
 
An additional part (Part B) was added to ARGX-113-1705 in order to provide the patients with 
the chance to have access to efgartigimod while it is not yet commercially available or available 
through another patient program. This extension to Part A of the trial will be a maximum of 2 
years and will also enable additional long-term safety and tolerability data to be collected. 
The extension part (Part B) will include fewer assessments to minimize the burden for the 
patients and changes in the SoC are allowed. 
Long-term safety follow-up will be carried out via local lab testing at the discretion of the 
investigator, as well as follow-up of AEs. 
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In Part A of the trial MG-ADL guidelines need to be followed for re-treatment. In Part B, 
MG-ADL will serve as a guide for re-treatment, but it is up to the investigator to decide when the 
patient will be re-treated. 
Protocol Version 2.0 compared to Protocol Version 3.0 
Changes from Protocol Version 2.0 compared to Protocol Version 3.0 are summarized below. 
Of note: updates of headers/footers and tables of contents as well as editorial changes regarding 
layout, font, and format are not recorded in this summary. 
Where changes have been made in a few words only these have been highlighted using italics. 
Section 
Change 
Rationale 
SUMMARY OF 
CHANGES 
A summary and table highlighting the differences 
between Part A and Part B of the trial was added. 
The Summary of Changes tables have been moved to 
Appendix 7. 
Due to the number of 
changes, and therefore the 
size of the tables required to 
describe all the changes made 
to the protocol, the detailed 
Summary of Changes tables 
have been moved to 
Appendix 7. 
SYNOPSIS 
Trial Duration: 
The trial duration will be 1 year. 
changed to 
The trial duration will be up to maximum 3 years. The 
trial consists of two parts: Part A (1 year) and Part B 
(up to maximum 2 years or until efgartigimod becomes 
commercially available or another option to access 
efgartigimod is available, whichever option comes 
first). 
See summary above. 
SYNOPSIS 
Objectives: 
 
2. TRIAL 
OBJECTIVES 
2.3. Tertiary 
Objectives 
Tertiary Objectives: 
… 
• To evaluate the immunogenicity of ARGX-113. 
changed to 
Tertiary Objectives: 
Part A only: 
… 
Part A and B: 
• To evaluate the immunogenicity of ARGX-113. 
SYNOPSIS 
Methodology: 
DESCRIPTION 
This is a 1-year, single-arm, open-label, multicenter, 
Phase 3 follow-on extension trial of ARGX-113-1704 
to evaluate the long-term safety and tolerability of 
ARGX-113 in patients with gMG. 
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Rationale 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
DESCRIPTION 
A variable number of Treatment Periods consisting of 
4 weekly infusions of ARGX-113 (10 mg/kg of body 
weight) infused over a period of 3 weeks will be 
administered to eligible patients on an “as needed 
basis” on top of their standard of care (SoC) in 
Treatment Periods. 
… 
The Study Entry Baseline (SEB) will be set at the first 
trial visit, while the Baseline of each subsequent 
Treatment Period (TPnB) will be set at Visit 1 of each 
corresponding Treatment Period. 
changed to 
This is a 3-year (maximum), single-arm, open-label, 
multicenter, Phase 3 follow-on extension trial of 
ARGX-113-1704 to evaluate the long-term safety and 
tolerability of ARGX-113 in patients with gMG. The 
trial consists of two parts: Part A (1 year) and Part B 
(maximum 2 years or until efgartigimod becomes 
commercially available or another option to access 
efgartigimod is available, whichever option comes 
first). The additional part (Part B) was added to 
ARGX-113-1705 in order to provide the patients with 
the chance to have access to efgartigimod while it is 
not yet commercially available or available through 
another patient program. This extension will also 
enable additional long-term safety and tolerability data 
to be collected. 
A variable number of Treatment Periods consisting of 
4 weekly infusions of ARGX-113 (10 mg/kg of body 
weight) infused over a period of 3 weeks will be 
administered to eligible patients on an “as needed 
basis” on top of their standard of care (SoC). 
… 
The Study Entry Baseline (SEB) will be set at the first 
trial visit, while the Baseline of each subsequent 
Treatment Period (TPnB for Part A or TPEnB for Part 
B) will be set at Visit 1 of each corresponding 
Treatment Period. 
SYNOPSIS 
Methodology: 
(RE-)TREATMENT 
 
(RE-)TREATMENT 
changed to 
(RE-)TREATMENT (Part A) 
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Section 
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Rationale 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
(RE-)TREATMENT 
SYNOPSIS 
Methodology: 
(RE-)TREATMENT 
(Part A) 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
(RE-)TREATMENT 
(Part A) 
Patients who show a treatment failure to ARGX-113 
for three consecutive Treatment Periods will be 
discontinued from further treatments with ARGX-113 
but will remain in the trial to receive appropriate 
alternative MG therapy. Treatment failure means the 
absence of a decrease of at least 2 points in total MG-
ADL score compared to the corresponding TPnB in at 
least 50% of the assessments (i.e., TPnV2, TPnV3, 
TPnV4 and the first post-Treatment Period visit).  
If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score but cannot 
complete the entire Treatment Period within the 
duration of the trial the patient should receive 
appropriate alternative MG therapy and continue to the 
EoS visit. 
changed to 
Patients who show a treatment failure to ARGX-113 
for three consecutive Treatment Periods will be 
discontinued from the trial. Treatment failure means 
the absence of a decrease of at least 2 points in total 
MG-ADL score compared to the corresponding TPnB 
in at least 50% of the assessments (i.e., TPnV2, TPnV3, 
TPnV4 and the first post-Treatment Period visit).  
If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score but cannot 
complete the entire Treatment Period within the 
duration of Part A (re-treatment in Part A can start at 
the latest on Day 336) then the patient will be 
transitioned to Part B after completing the End of Part 
A (EoA) visit. If the patient is not willing or able to 
continue to Part B then he/she should continue to the 
EoA visit. 
The transition to Part B can be either at ITPE0V1 or 
TPE1V1, depending on the patient’s status regarding 
the need for (re-)treatment upon transition from Part A. 
The first visit in Part B will always coincide with the 
EoA visit in Part A. The assessments done for the last 
visit in Part A should not be repeated in Part B. 
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(RE-)TREATMENT (Part B) 
If the patient feels that his/her condition has 
deteriorated, the Investigator may decide to start a new 
Treatment Period at the time of an Intertreatment 
Period (ITPE) visit or the patient may contact the 
Investigator for an unscheduled visit. 
Each patient can start a (new) Treatment Period with 
ARGX-113 when all the following criteria apply:  
The patient has completed the previous Treatment 
Period (i.e., after Visit 4)*; AND 
The Investigator determines that the patient will benefit 
from re-treatment; AND 
There is at least 1 calendar month (minimum 4 weeks) 
between Treatment Periods (i.e., between TPEnV4 and 
TPEn+1V1). 
*A patient who has had a temporary interruption of 
trial treatment in Part A may also continue into Part B 
of the trial and receive (re-)treatment if the conditions 
in Section 4.4.3 are met. 
However, patients may not receive (re-)treatment with 
ARGX-113 if, at the time of (re-)treatment, they have 
clinical evidence of bacterial, viral or fungal disease, or 
any other significant disease which could confound the 
results of the trial or put patients at undue risk. 
If a patient becomes eligible for (re-)treatment with 
ARGX-113 but cannot complete the entire Treatment 
Period within the duration of the trial, the patient 
should continue to the EoS visit. 
If the Investigator considers that the patient will not 
have a clinical benefit from (re-)treatment then the 
patient cannot start a new Treatment Period. The 
patient should then continue to the EoS visit. 
SYNOPSIS 
Methodology: 
STANDARD OF 
CARE (SoC) 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Permitted SoC for MG treatment under this protocol 
include … 
changed to 
In Part A: 
Permitted SoC for MG treatment under this protocol 
include … 
In Part B: 
A change of the type or dose/regimen of SoC 
(replacing, adding or removing SoC, or adjustment of 
See summary above. 
 
Part B allows for freedom of 
changing therapy and there 
will be no restrictions on the 
type of therapy that can be 
used. This because Part B 
will shift to a more real-life 
approach. 
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Section 
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Rationale 
Methodology 
STANDARD OF 
CARE 
the SoC dose and/or frequency) is allowed, without 
restrictions, following current medical practice. 
Plasma exchange (PLEX), intravenous 
immunoglobulin (IVIg), immunoadsorption or use of a 
new type of corticosteroid or an increased dose of the 
current corticosteroids used as stand-alone therapy or 
in combination is also allowed in Part B. 
SYNOPSIS 
Methodology: 
TIME BETWEEN 
TREATMENT 
CYCLES 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
TIME BETWEEN 
TREATMENT 
CYCLES 
TIME BETWEEN TREATMENT CYCLES 
At the end of each Treatment Period, … The visit 
frequency in the Intertreatment Period is every 30 days 
(± 2 days) after the previous visit. 
changed to 
TIME BETWEEN TREATMENT PERIODS 
At the end of each Treatment Period, … For Part A, the 
visit frequency in the Intertreatment Period is every 30 
days (± 2 days) after the previous visit. For Part B, the 
visit frequency in the Intertreatment Period is every 90 
days (± 7 days) after the previous visit. If an ITP visit 
for Part A is scheduled within 14 days of the EoA visit, 
then the EoA visit should be performed instead. 
Changed to be consistent 
with ARGX-113-1704. A 
Treatment Cycle is a 
Treatment Period + follow-
up. This section is describing 
Treatment Periods. 
 
Since in Part B the dosing 
regimen and visit schedule 
are more in line with a real-
life situation with quarterly 
visits to the treating 
physician, the frequency of 
the ITP visits has been 
reduced to once every 90 
days. However, should the 
Investigator, together with 
the patient, deem it necessary 
the patient can return sooner. 
SYNOPSIS 
Methodology: 
RESCUE THERAPY  
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
RESCUE THERAPY 
 
6.  TRIAL 
TREATMENT 
RESCUE THERAPY  
Rescue therapy will be limited to plasma exchange 
(PLEX), intravenous immunoglobulin (IVIg), 
immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current 
corticosteroids used as stand-alone therapy or in 
combination. 
… 
In situations where the treatments as listed above are 
given under the protocol-defined rescue criteria, 
patients will be discontinued early from trial treatment. 
changed to 
RESCUE THERAPY (Part A only) 
Rescue therapy will be limited to PLEX, IVIg, 
immunoadsorption or use of a new type of 
corticosteroid or an increased dose of the current 
corticosteroids used as stand-alone therapy or in 
combination. 
See summary above. 
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6.8.  Prior Treatments 
and Concomitant 
Medications 
6.8.2.  Rescue Therapy 
… 
In situations where the treatments as listed above are 
given under the protocol-defined rescue criteria, 
patients will be discontinued early from the trial. 
SYNOPSIS 
Methodology: 
EARLY 
DISCONTINUATION 
FROM THE TRIAL 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
EARLY 
DISCONTINUATION 
FROM THE TRIAL 
Section deleted: 
EARLY DISCONTINUATION FROM THE TRIAL 
Any patient prematurely discontinuing the trial should 
perform the EoS/ED assessments. 
In order to reduce the burden 
on the patients, the safety 
follow-up period has been 
replaced by 1 safety follow-
up visit. As a result there is 
no longer a difference 
between discontinuation from 
trial treatment or from the 
trial. 
 
Therefore if the patient can 
no longer receive the study 
drug for any reason, the 
patient will be able to leave 
the trial after a limited safety 
follow-up period. 
 
If warranted further safety 
follow-up can be performed 
by the Investigator and the 
relevant information captured 
in the safety database. 
SYNOPSIS 
Methodology: 
EARLY 
DISCONTINUATION 
FROM TRIAL 
TREATMENT 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
EARLY 
DISCONTINUATION 
FROM TRIAL 
TREATMENT 
EARLY DISCONTINUATION FROM TRIAL 
TREATMENT 
Patients who discontinue early from trial treatment 
within a Treatment Period will have to complete the 
End of Treatment (EoT) assessments and complete the 
remaining visits in the current Treatment Period 
according to the General Schedule of Assessments 
(Table 1). These patients will not receive any further 
administration of ARGX-113 during the trial and will 
continue to be followed for safety and disease severity 
as per Schedule of Assessments for Patients who 
Discontinue Early from Trial Treatment (Table 2).  
Patients who discontinue early from trial treatment in 
the Intertreatment Period will have to complete the 
EoT assessments and then continue into the Safety and 
Disease Severity Follow-up period as per Table 2. 
changed to 
EARLY DISCONTINUATION 
For patients who discontinue early from trial, the 
assessments will depend on the visit at which it was 
decided that the patient had to discontinue (see 
Section 5.4, Figure 1, and Figure 2). 
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Patients who discontinue early from the trial within a 
Treatment Period should perform the planned 
assessments of the corresponding Treatment Period 
visit. These patients will not receive any further 
administration of ARGX-113 during the trial and will 
return for the ED visit one month (30 ± 2 days) after 
the last dose administration. An unscheduled visit can 
be organized if deemed necessary by the Investigator. 
Patients who discontinue early from the trial between 
the last visit of a Treatment Period (TPnV4 or TPEnV4) 
and the next Intertreatment Period visit (ITPnVn or 
ITPEnVn) should perform the ED assessments one 
month (30 ± 2 days) after the last dose administration. 
Patients who discontinue early from the trial at the ITP 
(Part A) or ITPE (Part B) visit should perform the ED 
assessments, instead of the ITPnVn (Part A) or 
ITPEnVn (Part B) assessments. 
Patients who discontinue early from the trial after the 
ITP (Part A) or ITPE (Part B) visit should perform the 
ED assessments. 
Any patient prematurely discontinuing the trial during 
Part A should perform the EoA/ED assessments 
according to the General Schedule of Assessments for 
Part A (Table 1). Any patient prematurely 
discontinuing the trial during Part B should perform 
the EoS/ED assessments according to the General 
Schedule of Assessments for Part B (Table 2). 
SYNOPSIS 
TEMPORARY 
INTERRUPTION 
FROM TRIAL 
TREATMENT 
 
4.  
INVESTIGATIONAL 
PLAN  
4.1. Summary of Trial 
Design 
Methodology 
TEMPORARY 
INTERRUPTION 
FROM TRIAL 
TREATMENT 
A patient who does not need to be discontinued early 
from trial treatment might still … 
A schematic of trial design is presented in Figure 1. 
changed to: 
A patient who does not need to be discontinued early 
from the trial might still … 
Patients for whom treatment is interrupted will have to 
complete the current Treatment Period and will 
continue the trial as per the General Schedule of 
Assessments for Part A (Table 1) or for Part B (Table 
2) but without drug administration. A patient who has 
had a temporary interruption of trial treatment in Part 
A may also continue into Part B of the trial and receive 
(re-)treatment if the conditions mentioned above are 
met. 
A schematic of the trial design is presented in Figure 1 
for Part A and in Figure 2 for Part B. 
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SYNOPSIS 
Exclusion Criteria 
 
4.  
INVESTIGATIONAL 
PLAN 
4.3.  Selection of Trial 
Population 
4.3.2.  Exclusion 
Criteria 
1. Patients who discontinued early from trial ARGX-
113-1704 or patients who discontinued early from 
randomized treatment for rescue or pregnancy reasons 
or an (S)AE that might jeopardize the safety of the 
patient in that trial. 
changed to 
1. Patients who discontinued early from trial ARGX-
113-1704 or patients who discontinued early from 
randomized treatment for rescue or pregnancy reasons 
or an SAE that is likely to result in a life-threatening 
situation or pose a serious safety risk. 
Corrected. This was amended 
in Section 4.4.2 in a previous 
amendment (2.0), but was not 
amended in the exclusion 
criteria. 
SYNOPSIS 
Criteria for 
Evaluation: 
 
3. TRIAL 
ENDPOINTS 
3.1. Primary Endpoint 
3.2. Secondary 
Endpoint 
3.3. Tertiary 
Endpoints 
Primary Endpoint: 
• Incidence and severity of AEs, SAEs, vital signs, 
electrocardiogram (ECG) and laboratory assessments 
over 1 year in AChR-Ab seropositive patients. 
Secondary Endpoints: 
• Incidence and severity of AEs, SAEs, vital signs, 
ECG and laboratory assessments over 1 year in the 
overall population (AChR-Ab seropositive patients and 
AChR-Ab seronegative patients). 
• Incidence and severity of AEs, SAEs, vital signs, 
ECG and laboratory assessments at each Treatment 
Period in AChR-Ab seropositive patients. 
• Incidence and severity of AEs, SAEs, vital signs, 
ECG and laboratory assessments at each Treatment 
Period in the overall population (AChR-Ab 
seropositive patients and AChR-Ab seronegative 
patients).  
Tertiary Endpoints 
• To evaluate the disease severity as assessed by total 
MG-ADL score changes compared to SEB and the 
corresponding TPnB in AChR-Ab seropositive patients. 
• To evaluate the disease severity as assessed by total 
MG-ADL score changes compared to SEB and the 
corresponding TPnB in the overall population (AChR-
Ab seropositive and AChR-Ab seronegative patients). 
• To evaluate the disease severity as assessed by total 
QMG score changes compared to SEB and the 
corresponding TPnB in AChR-Ab seropositive 
patients. 
• To evaluate the disease severity as assessed by total 
QMG score changes compared to SEB and the 
Endpoints streamlined to 
reflect what will actually be 
summarized and labels added 
to clarify what will be 
analyzed in Part A and Part B 
of the trial. 
 
Corrected to reflect that 
changes from the treatment 
period baseline of the first 
cycle will be summarized 
(instead of changes from 
SEB) as patients might start 
the study with an 
intertreatment period. 
 
“To evaluate the disease 
severity as assessed by” 
should not be part of an 
endpoint definition. 
 
 
 
For Part B only 
immunogenicity will be 
characterized as a tertiary 
endpoint. Furthermore, only 
safety and tolerability will be 
followed up and no PD 
markers will be summarized. 
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corresponding TPnB in the overall population (AChR-
Ab seropositive and AChR-Ab seronegative patients). 
• Percentage decrease (compared to SEB and the 
corresponding TPnB) of total IgG level and IgG 
subtypes in ARGX-113 (re-)treated patients. 
• Percentage decrease (compared to SEB and the 
corresponding TPnB) of autoantibodies (anti-AChR 
antibodies and anti-MuSK antibodies) in ARGX-113 
(re-)treated patients. 
• Incidence of anti-drug antibodies (ADA) to ARGX-
113 at SEB and at each Treatment Period. 
changed to 
Primary Endpoint: 
• Incidence and severity of AEs, SAEs, vital signs, 
electrocardiogram (ECG) and laboratory assessments 
over the duration of the trial in AChR-Ab seropositive 
patients. 
Secondary Endpoint: 
• Incidence and severity of AEs, SAEs, vital signs, 
ECG and laboratory assessments over the duration of 
the trial in the overall population (AChR-Ab 
seropositive patients and AChR-Ab seronegative 
patients). 
Tertiary Endpoints: 
Part A only: 
• Total MG-ADL score changes compared to the 
Treatment Period Baseline of the first cycle (TP1B) and 
the corresponding TPnB in AChR-Ab seropositive 
patients. 
• Total MG-ADL score changes compared to TP1B and 
the corresponding TPnB in the overall population 
(AChR-Ab seropositive and AChR-Ab seronegative 
patients). 
• Total QMG score changes compared to TP1B and the 
corresponding TPnB in AChR-Ab seropositive patients. 
• Total QMG score changes compared to TP1B and the 
corresponding TPnB in the overall population (AChR-
Ab seropositive and AChR-Ab seronegative patients). 
• Percentage decrease (compared to TP1B and the 
corresponding TPnB) of total IgG level and IgG 
subtypes in ARGX-113 (re-)treated patients. 
• Percentage decrease (compared to TP1B and the 
corresponding TPnB) of autoantibodies (anti-AChR 
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antibodies and anti-MuSK antibodies) in ARGX-113 
(re-)treated patients. 
Part A and B: 
• Incidence and prevalence of anti-drug antibodies 
(ADA) to ARGX-113. 
SYNOPSIS 
Statistical Methods 
and Plan: 
 
A Statistical Analysis Plan detailing all statistical 
methods and analyses will be issued before the 
database lock. A summary of the plan is described 
below. 
All endpoints will be tested in all enrolled patients and 
by means of descriptive statistics. All comparisons of 
endpoints between Treatment Periods will be purely 
descriptive. 
Summary statistics will be provided for the continuous 
endpoints (e.g., total MG-ADL score, total QMG 
score, levels of total IgG and subtypes, anti-
AChR/anti-MuSK antibodies, laboratory values, vital 
signs, ECG) in terms of absolute values and changes 
from SEB and changes from Treatment Period 
Baseline (TPB), at each Treatment Period (including 
Intertreatment Period) and available time points. 
Frequency tables will be made for all binary variables, 
i.e., AEs and ADA for all Treatment Periods and 
overall (including Intertreatment Periods) and available 
time points. 
changed to 
A Statistical Analysis Plan detailing all statistical 
methods and analyses will be issued before any 
database lock. A summary of the plan is described 
below. 
All endpoints will be summarized in all enrolled 
patients and by means of descriptive statistics. 
Summary statistics will be provided for the continuous 
endpoints (e.g., total MG-ADL score, total QMG 
score, levels of total IgG and subtypes, anti-
AChR/anti-MuSK antibodies, laboratory values, vital 
signs, ECG) in terms of absolute values, changes from 
TP1B or changes from TPnB, by cycle and available 
time points. 
Frequency tables will be made for all binary variables, 
i.e., AEs and ADA by cycle and overall. 
Corrected to reflect that 
changes from the treatment 
period baseline of the first 
cycle will be summarized 
(instead of changes from 
SEB), as patients might start 
the study with an 
intertreatment period. 
AEs and ADA will be 
summarized by cycle, not by 
timepoint. 
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Table 1  General 
Schedule of 
Assessments 
Title:  
Table 1  General Schedule of Assessments 
changed to 
Table 1  General Schedule of Assessments for Part A 
See summary above. 
Table 1  General 
Schedule of 
Assessments  
End of Study/Early 
Discontinuation 
End of Study/Early Discontinuation 
EoS/ED 
changed to 
End of Part A/Early Discontinuation 
EoA/ED 
Table 1  General 
Schedule of 
Assessments 
Trial Day (Visit 
Windows) 
Trial Day (Visit Windows): 
(X+8)±1/ (X+15)±1/ (X+22)±1 
changed to 
(X+7)±1/ (X+14)±1/ (X+21)±1 
Trial Day (Visit Windows) 
timings were corrected. 
Table 1  General 
Schedule of 
Assessments 
Trial Day (Visit 
Windows) 
Trial Day (Visit Windows): 
Y (±2) 
changed to 
Y+30 (±2) 
Clarification added that these 
visits occur 30 days after the 
previous visit. 
Table 1  General 
Schedule of 
Assessments 
Deleted: 
EoTn 
There is no End of Treatment 
visit. 
Table 1  General 
Schedule of 
Assessments 
Text added: 
Y=previous visit 
Y added to footnotes for 
clarification. 
Table 1 General 
Schedule of 
Assessments  
Footnote 
EoS/ED=End of Study/Early Discontinuation; 
changed to 
EoA/ED=End of Part A/Early Discontinuation; 
See summary above. 
Table 1 General 
Schedule of 
Assessments  
Footnote 
Deleted: 
EoT=End of Treatment 
There is no End of Treatment 
visit. 
Table 1 General 
Schedule of 
Assessments  
b The intertreatment period visits (ITPnVn) occur every 
30 days after the previous visit. The visit denominator 
(‘n’) will start at 1 at each period. At each ITPnVn, an 
See summary above. 
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Footnote b 
evaluation of the need for (re-)treatment should be 
done prior to decide whether assessments listed for 
ITPnVn or TPnV1 are to be performed. 
changed to 
b The intertreatment period visits (ITPnVn) occur every 
30 days after the previous visit (Y). The visit 
denominator (‘n’) will start at 1 at each period. At each 
ITPnVn, an evaluation of the need for (re-)treatment 
should be done prior to deciding whether the 
assessments listed for ITPnVn or TPnV1 are to be 
performed. If an ITP visit for Part A is scheduled 
within 14 days of the EoA visit, then this EoA visit 
should be performed instead. For patients that 
discontinue at the ITP visit this will then serve as the 
EoA/ED visit. 
Table 1  General 
Schedule of 
Assessments  
Footnote c 
c  If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score but cannot 
complete the entire Treatment Period within the trial 
duration, the patient should receive appropriate 
alternative MG therapy and continue to the EoS visit. 
changed to 
c  If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score, but cannot 
complete the entire Treatment Period within Part A of 
the trial (re-treatment in Part A can start at the latest on 
Day 336), then the patient will be transitioned to Part B 
after completing the EoA visit. If the patient is not 
willing or able to continue to Part B then they should 
continue to the EoA visit. The transition to Part B can 
be either ITPE0V1 or TPE1V1, depending on the 
patient status regarding the need for (re-)treatment 
upon transition from Part A. The first visit in Part B 
will always coincide with the EoA visit in Part A. The 
assessments done for the last visit in Part A should not 
be repeated in Part B. 
Footnote c was added to the assessment End of Part A. 
Table 1  General 
Schedule of 
Assessments  
Footnote d 
d An unscheduled (UNS) visit can be on request of the 
patient or the Investigator. 
changed to 
d An unscheduled (UNS) visit can occur at the request 
of the patient or the Investigator. 
Use of language corrected. 
Table 1  General 
Schedule of 
Assessments  
i Weight will be measured at SEB, at the EoS/ED visit, 
and when there is an obvious weight change compared 
to the last weight assessment. 
See summary above. 
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Footnote i 
changed to 
i Weight will be measured at SEB, at the EoA/ED visit, 
and when there is an obvious weight change compared 
to the last weight assessment. 
Table 1  General 
Schedule of 
Assessments  
Footnote s 
s For patients who discontinue early from trial 
treatment, the assessments will depend on the visit at 
which it was decided that the patient had to discontinue 
trial treatment (see Section 5.4). Patients who 
discontinue early from trial treatment within a 
Treatment Period will have to complete the EoT 
assessments and complete the remaining visits in the 
current Treatment Period according to this Schedule of 
Assessments. These patients will not receive any 
further administration of ARGX-113 during the trial 
and will continue to be followed for safety and disease 
severity as per Schedule of Assessments for Patients 
who Discontinued Early from Trial Treatment (Table 
2). Patients who discontinue early from trial treatment 
in the Intertreatment Period will have to complete the 
EoT assessments and then continue into the Safety and 
Disease Severity Follow-up period per Table 2. 
changed to 
s For patients who discontinue early from trial, the 
assessments will depend on the visit at which it was 
decided that the patient had to discontinue (see Section 
5.4). Patients who discontinue early from the trial 
within a Treatment Period should perform the planned 
assessments of the corresponding Treatment Period 
visit. These patients will not receive any further 
administration of ARGX-113 during the trial and will 
return for the ED visit one month (30 ± 2 days) after 
the last dose administration. An unscheduled visit can 
be organized if deemed necessary by the Investigator. 
Patients who discontinue early from the trial between 
the last visit of a Treatment Period (TPnV4) and the 
next intertreatment period visit (ITPnVn) should 
perform the ED assessments one month (30 ± 2 days) 
after the last dose administration. Patients who 
discontinue early from the trial at the ITP visit should 
perform the ED assessments, instead of the ITPnVn 
assessments. Patients who discontinue early from the 
trial after the ITP visit should perform the ED 
assessments. 
Footnote s was added to the assessment Early 
Discontinuation. 
In order to simplify the safety 
follow-up the different 
scenarios have now been 
linked to the last dose, in 
order to see what schedule 
needs to be followed for 
further safety follow-up. 
 
There is no End of Treatment 
visit. 
Table 2: Schedule of 
Assessments for 
Table 2 was deleted. 
Patients will not be followed 
for safety and disease 
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Patients who 
Discontinued Early 
from Trial Treatmenta 
severity every 30 days. The 
new scenario for early 
discontinuation means that 
patients should perform the 
ED visit instead (at least 30 
days after the last 
administration of study drug). 
Figure 1: ARGX-113-
1705 Trial Design 
Scenario for early discontinuation added. 
Figure 1: ARGX-113-
1705 Trial Design 
Footnotes for ED, EoA, SEB and SoC added 
See summary above. 
Title: 
Figure 1: ARGX-113-1705 Trial Design 
changed to 
Figure 1: ARGX-113-1705 Trial Design for Part A 
EoS 
changed to 
EoA 
Table 2  General 
Schedule of 
Assessments for Part 
B  
A new table for the Schedule of Assessments for Part 
B has been added. 
Figure 2: ARGX-113-
1705 Trial Design for 
Part B 
A new figure for the Trial Design for Part B has been 
added. 
LIST OF 
ABBREVIATIONS 
List of abbreviations updated to include cycle, EoA, 
EoS, ITPEV, TP, TPE, TPEnB and TPEV, and EoT 
removed. 
4.  
INVESTIGATIONAL 
PLAN 
4.2.  Discussion of 
Trial Design 
This trial is designed as a 1-year, single-arm, open-
label, follow-on extension trial of ARGX-113-1704. 
With the exception of patients who discontinued early 
from trial ARGX-113-1704 or patients who 
discontinued early from trial treatment for rescue or 
pregnancy reasons or an (S)AE that might jeopardize 
the safety of the patient in that trial, all participants of 
trial ARGX-113-1704 who reached the EoS visit (Day 
182) are allowed to roll over into this trial. 
The first visit of trial ARGX-113-1705 will coincide 
with the last visit of trial ARGX-113-1704 for each 
patient. 
changed to 
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This trial is designed as a 3-year (maximum), single-
arm, open-label, follow-on extension trial of ARGX-
113-1704. The trial consists of two parts: Part A (1 
year) and Part B (up to maximum 2 years or until 
efgartigimod becomes commercially available or 
another option to access efgartigimod is available, 
whichever option comes first. The additional part (Part 
B) was added to ARGX-113-1705 in order to provide 
the patients with the chance to have access to 
efgartigimod while it is not yet commercially available 
or available through another patient program. This 
extension will also enable additional long-term safety 
and tolerability data to be collected. 
With the exception of patients who discontinued early 
from trial ARGX-113-1704 or patients who 
discontinued early from trial treatment for rescue or 
pregnancy reasons or an SAE that is likely to result in a 
life-threatening situation or pose a serious safety risk, 
all participants of trial ARGX-113-1704 who reached 
the EoS visit are allowed to roll over into this trial. 
The first visit of trial ARGX-113-1705 will coincide 
with the last visit of trial ARGX-113-1704 for each 
patient. 
In the same way, with the exception of patients who 
discontinued early from Part A of this trial, all 
participants of Part A who reached the EoA visit can 
be transitioned to Part B of this trial. 
The first visit of Part B of this trial will coincide with 
the last visit of Part A for each patient. 
4.  
INVESTIGATIONAL 
PLAN 
4.2.  Discussion of 
Trial Design 
A change of the type or dose/regimen of SoC … 
… 
The chosen primary and secondary endpoints in this 
trial are to evaluate the long-term safety and 
tolerability of ARGX-113 over 1 year and at each 
Treatment Period in AChR-Ab seropositive patients 
and in the overall population (AChR-Ab seropositive 
and seronegative patients). 
changed to 
In Part A, a change of the type or dose/regimen of SoC 
… 
… 
In Part B, a change of the type or dose/regimen of SoC 
(replacing, adding or removing SoC, or adjustment of 
See summary above. 
 
Part B allows for freedom of 
changing therapy and there 
will be no restrictions on the 
type of therapy that can be 
used. This because Part B 
will shift to a more real-life 
approach. 
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the SoC dose and/or frequency) is allowed, without 
restrictions, following current medical practice. 
PLEX, IVIg, immunoadsorption or use of a new type 
of corticosteroid or an increased dose of the current 
corticosteroids used as stand-alone therapy or in 
combination is also allowed in Part B. 
The chosen primary and secondary endpoints in this 
trial are to evaluate the long-term safety and 
tolerability of ARGX-113 over the duration of the 
trial, as well as by cycle, in AChR-Ab seropositive 
patients and in the overall population (AChR-Ab 
seropositive and seronegative patients). 
4.  
INVESTIGATIONAL 
PLAN 
4.4.  Early 
Discontinuation 
4.4.  Early Discontinuation 
… 
4.4.1.  Early Discontinuation from Trial 
… Patients must be discontinued early from the trial 
and complete the EoS/ED visit if: 
• They withdraw their consent. 
• The Investigator, after discussion with the sponsor’s 
Medical Director, deems it is in the patient’s best 
interest. 
All patients are free to withdraw consent from 
participation in the trial at any time, for any reason, 
specified or unspecified, and without prejudice to 
further treatment. Prior to actual withdrawal of 
consent, an effort should be made to perform a final set 
of assessments as per EoS/ED visit in the General 
Schedule of Assessments (Table 1). Investigators will 
make and document all efforts made to contact those 
patients who do not return for scheduled visits. 
changed to 
4.4.  Early Discontinuation 
… 
… Patients must be discontinued early from the trial if: 
• They withdraw their consent. 
• The Investigator, after discussion with the sponsor’s 
Medical Director, deems it is in the patient’s best 
interest. 
• Patient is pregnant. 
• Patients receives rescue therapy. 
In order to reduce the burden 
on the patients, the safety 
follow-up period has been 
replaced by 1 safety follow-
up visit. As a result there is 
no longer a difference 
between discontinuation from 
trial treatment or from the 
trial. 
 
Therefore if the patient can 
no longer receive the study 
drug for any reason, the 
patient will be able to leave 
the trial after a limited safety 
follow-up period. 
 
If warranted further safety 
follow-up can be performed 
by the Investigator and the 
relevant information captured 
in the safety database. 
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• Patient develops an SAE that is likely to result in a 
life-threatening situation or pose a serious safety risk to 
the patient. 
• Prohibited medication is taken (see Section 6.8.1). 
Patients might discontinue early from the trial if: 
•  Patient has clinical evidence of bacterial, viral or 
fungal disease or any other significant disease which 
could confound the results of the trial or put the patient 
at undue risk. In this situation, decision on whether or 
not to discontinue patients early from trial will depend 
on the evaluation on a case-by-case basis. Patients 
who, after evaluation of the above situations are not 
discontinued from the trial, may have a temporary 
interruption from trial treatment (see Section 4.4.1). 
For patients who discontinue early from trial, the 
assessments will depend on the visit at which it was 
decided that the patient had to discontinue (see Section 
5.4). 
Patients who discontinue early from the trial within a 
Treatment Period should perform the planned 
assessments of the corresponding Treatment Period 
visit. These patients will not receive any further 
administration of ARGX-113 during the trial and will 
return for the ED visit one month (30 ± 2 days) after 
the last dose administration. An unscheduled visit can 
be organized if deemed necessary by the Investigator. 
Patients who discontinue early from the trial between 
the last visit of a Treatment Period (TPnV4 or TPEnV4) 
and the next Intertreatment Period visit (ITPnVn or 
ITPEnVn) should perform the ED assessments one 
month (30 ± 2 days) after the last dose administration. 
Patients who discontinue early from the trial at the ITP 
(Part A) or ITPE (Part B) visit should perform the ED 
assessments, instead of the ITPnVn (Part A) or 
ITPEnVn (Part B) assessments. 
Patients who discontinue early from the trial after the 
ITP (Part A) or ITPE (Part B) visit should perform the 
ED assessments. 
Any patient prematurely discontinuing the trial during 
Part A should perform the EoA/ED assessments 
according to the General Schedule of Assessments for 
Part A (Table 1). Any patient prematurely 
discontinuing the trial during Part B should perform 
the EoS/ED assessments according to the General 
Schedule of Assessments for Part B (Table 2). 
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All patients are free to withdraw consent from 
participation in the trial at any time, for any reason, 
specified or unspecified, and without prejudice to 
further treatment. Prior to actual withdrawal of 
consent, an effort should be made to perform a final set 
of assessments as per the EoA/ED visit in the General 
Schedule of Assessments for Part A (Table 1) or the 
EoS/ED visit in the General Schedule of Assessments 
for Part B (Table 2). Investigators will make and 
document all efforts made to contact those patients 
who do not return for scheduled visits. 
4.  
INVESTIGATIONAL 
PLAN 
4.4.  Early 
Discontinuation 
4.4.2.  Early 
Discontinuation from 
Trial Treatment 
Section deleted. 
4.  
INVESTIGATIONAL 
PLAN 
4.4.  Early 
Discontinuation 
4.4.3.  Temporary 
Interruption from Trial 
Treatment 
A patient who does not need to be discontinued early 
from trial treatment might still have a temporary 
interruption from trial treatment. … 
Patients for whom treatment is interrupted will have to 
complete the current Treatment Period and will 
continue the trial as per General Schedule of 
Assessments (Table 1). 
changed to 
A patient who does not need to be discontinued early 
from the trial might still have a temporary interruption 
from trial treatment. … 
Patients for whom treatment is interrupted will have to 
complete the current Treatment Period and will 
continue the trial as per the General Schedule of 
Assessments for Part A (Table 1) or for Part B (Table 
2). A patient who has had a temporary interruption of 
trial treatment in Part A may also continue into Part B 
of the trial and receive (re-)treatment if the conditions 
mentioned above are met. 
4.  
INVESTIGATIONAL 
PLAN 
4.4.  Early 
Discontinuation 
Patients who miss one, two or three infusions per 
Treatment Period will stay in the trial and will follow 
the assessments as per General Schedule of 
Assessments (Table 1). These patients may be eligible 
for further Treatment Periods during the trial. 
changed to 
See summary above. 
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4.4.4. 
Missed Doses 
Patients who miss one, two or three infusions per 
Treatment Period will stay in the trial and will follow 
the assessments as per the General Schedule of 
Assessments for Part A (Table 1) or for Part B 
(Table 2). These patients may be eligible for further 
Treatment Periods during the trial. A patient who has 
missed doses in Part A may also continue into Part B 
of the trial and receive (re-)treatment if the conditions 
in Section 4.4.3 are met. 
5.  TRIAL 
PROCEDURES 
Patients should be seen for all visits on the designated 
days or as closely as possible to the original planned 
visit schedule. There is a permissible window of ±1 
day for Treatment Period visits (Visit 1 to Visit 4), of 
±2 days for ITPnVn, and of ±7 days for the EoS visit 
(Day 365). Every effort should be made to schedule 
every visit on the exact day (which is relative to the 
Baseline visit [SEB or TPnB]) within the window as 
described in the General Schedule of Assessments 
(Table 1). 
… 
The SEB will be set at the first trial visit, while the 
Baseline of each subsequent Treatment Period (TPnB) 
will be set at Visit 1 of each corresponding Treatment 
Period. 
… The MG-ADL scale needs to be performed prior to 
the QMG scale. Acetylcholinesterase inhibitors must 
be halted for at least 12 hours before the QMG 
assessment. 
… 
As from signature of informed consent until EoS, all 
AEs that occur … 
Patients who are discontinued early from trial 
treatment, after they have completed the EoT 
assessments and, if applicable, the remaining visits of 
the current Treatment Period, will return every month 
(30 ± 2 days) for Follow-up visits until Day 365 as per 
Schedule of Assessments for Patients who 
Discontinued Early from Trial Treatment (Table 2). 
These patients will then continue in the trial to be 
followed for safety and disease severity. 
changed to 
Patients should be seen for all visits on the designated 
days or as closely as possible to the original planned 
visit schedule. There is a permissible window of ±1 
day for Treatment Period visits (Visit 1 to Visit 4), of 
±2 days for ITPnVn (Part A), and of ±7 days for the 
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ITPEnVn (Part B), EoA visit (Day 365) and EoS visit 
(Day 1095 or when efgartigimod becomes 
commercially available or another option to access 
efgartigimod is available, whichever option comes 
first). Every effort should be made to schedule every 
visit on the exact day (which is relative to the Baseline 
visit [SEB, or TPnB or TPEnB]) within the window as 
described in the General Schedule of Assessments for 
Part A (Table 1) and for Part B (Table 2). 
… 
The SEB will be set at the first trial visit, while the 
Baseline of each subsequent Treatment Period (TPnB or 
TPEnB) will be set at Visit 1 of each corresponding 
Treatment Period. 
… The MG-ADL scale needs to be performed prior to 
the QMG scale (Part A) as per Table 1. 
Acetylcholinesterase inhibitors must be halted for at 
least 12 hours before the QMG assessment (Part A). 
… 
As from signature of informed consent until last study 
visit, all AEs that occur … 
5.  TRIAL 
PROCEDURES 
5.2.  Treatment Period 
… A new Treatment Period can only be started if it can 
be completed within the 1-year trial duration. 
changed to 
5.2.1.  Treatment Period Part A 
… A new Treatment Period can only be started if it can 
be completed within the 1-year trial duration of Part A 
of the trial (re-treatment in Part A can start at the latest 
on Day 336). Otherwise the patient can be transitioned 
to Part B after completing the EoA visit. If the patient 
is not willing or able to continue to Part B, then he/she 
should continue to the EoA visit. 
5.  TRIAL 
PROCEDURES 
5.2.  Treatment Period 
5.2.1.  Treatment 
Period Part A 
Patients who fail to respond to ARGX-113 for three 
consecutive Treatment Periods will be discontinued 
from further treatments with ARGX-113 but will 
remain in the trial to receive appropriate alternative 
MG therapy. …  
If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score but cannot 
complete the entire Treatment Period within the trial 
duration, the patient should receive appropriate 
alternative MG therapy and continue to the EoS visit. 
changed to 
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Patients who fail to respond to ARGX-113 for three 
consecutive Treatment Periods will be discontinued 
from the trial. … 
If a patient becomes eligible for (re-)treatment with 
ARGX-113 per total MG-ADL score but cannot 
complete the entire Treatment Period within Part A of 
the trial (re-treatment in Part A can start at the latest on 
Day 336) then the patient will be transitioned to Part B 
after completing the EoA visit. If the patient is not 
willing or able to continue to Part B then he/she should 
continue to the EoA visit. 
The transition to Part B can be either ITPE0Vn or 
TPE1V1, depending on the patient status regarding the 
need for (re-)treatment upon transition from Part A. 
The first visit in Part B will always coincide with the 
EoA visit in Part A. The assessments done for the last 
visit in Part A should not be repeated in Part B. 
5.  TRIAL 
PROCEDURES 
5.2.  Treatment Period 
5.2.2.  Treatment 
Period Part B 
Extra section added for Part B: 
5.2.2. 
Treatment Period Part B 
A Treatment Period will include assessments in 4 
weekly visits including treatment with ARGX-113 in 
eligible patients in need for (re-)treatment. A new 
Treatment Period can only be started if it can be 
completed within the trial duration (up to maximum 3 
years or until efgartigimod becomes commercially 
available or another option to access efgartigimod is 
available, whichever option comes first). 
The following assessments will be performed from 
Visit 1 to Visit 4 of each Treatment Period: 
• Assessments of disease severity (MG-ADL scale). (*) 
• Weight will be measured at Visit 1 and when there is 
an obvious weight change compared to the last weight 
assessment.(*) 
• Vital signs.(*) 
• Clinical laboratory tests (local labs), only at Visit 1 
and Visit 4 of each Treatment Period.(*) 
• Urinalysis, only at Visit 1 and Visit 4 of each 
Treatment Period.(*) 
• Urine pregnancy test (only for women of childbearing 
potential, see DEFINITION OF TERMS), only at Visit 
1 and Visit 4 of each Treatment Period.(*) 
• ADA, only at Visit 1 of each Treatment Period (*) 
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• Administration of ARGX-113 as an IV infusion over 
a period of 1 hour. Patients will remain at the site for at 
least 1 hour following the end of the infusion for safety 
monitoring, based on the patient’s clinical status.  
• Review of concomitant medication. 
• Assess AEs if any. 
(*) These assessments should be performed prior to 
administration of ARGX-113 (predose). 
At Visit 1 of each Treatment Period, the conditions for 
(re-)treatment will be checked before administration of 
ARGX-113 (see Section 4.1). 
Patients may not receive (re-)treatment with ARGX-
113 if, at the time of (re-)treatment, they have clinical 
evidence of bacterial, viral or fungal disease, or any 
other significant disease which could confound the 
results of the trial or put patients at undue risk. 
If a patient becomes eligible for (re-)treatment with 
ARGX-113 but cannot complete the entire Treatment 
Period within the duration of the trial, the patient 
should continue to the EoS visit. 
If the Investigator considers that the patient will not 
have a clinical benefit from re-treatment then the 
patient cannot start a new Treatment Period. The 
patient should then continue to the EoS visit. 
A change of the type or dose/regimen of SoC 
(replacing, adding or removing SoC, or adjustment of 
the SoC dose and/or frequency) is allowed, without 
restrictions, following current medical practice. 
5.  TRIAL 
PROCEDURES 
5.3.  Intertreatment 
Period 
Intertreatment Period visits occur every 30 days after 
the previous visit. 
At each ITPnVn, an evaluation of the need for (re-
)treatment should be done. In case the patient is not in 
need of (re-)treatment, assessments for ITPnVn should 
be performed as listed below and per the General 
Schedule of Assessments (Table 1). However, in case 
the evaluation shows that the patient is in need of 
(re-)treatment and is also eligible for (re-)treatment, the 
assessments according to TPnV1 are to be performed 
instead (see Section 5.2). 
The following assessments will be performed: 
changed to 
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Intertreatment Period visits occur every 30 days after 
the previous visit in Part A and every 90 days after the 
previous visit in Part B. 
At each ITPnVn (Part A) or ITPEnVn, (Part B) an 
evaluation of the need for (re-)treatment should be 
done. In case the patient is not in need of (re-
)treatment, assessments for ITPnVn (Part A) or 
ITPEnVn (Part B) should be performed as listed below 
and per the General Schedule of Assessments for Part 
A (Table 1) or for Part B (Table 2). However, in case 
the evaluation shows that the patient is in need of (re-
)treatment and is also eligible for (re-)treatment, the 
assessments according to TPnV1 (Part A) or TPEnV1 
(Part B) are to be performed instead (see Section 5.2). 
If an ITP visit for Part A is scheduled within 14 days of 
the EoA visit, then the EoA visit should be performed 
instead. 
The following assessments will be performed in Part 
A: 
5.  TRIAL 
PROCEDURES 
5.3.  Intertreatment 
Period 
The following text added: 
The following assessments will be performed in Part 
B: 
• Assessments of disease severity (MG-ADL scale). 
• Vital signs. 
• Urine pregnancy test (only for women of childbearing 
potential, see DEFINITION OF TERMS). 
• Review of concomitant medication. 
• Assess AEs, if any. 
5.  TRIAL 
PROCEDURES 
5.4.  End of Treatment 
Section deleted. 
There is no End of Treatment 
visit. 
5.  TRIAL 
PROCEDURES 
5.5.  Safety and 
Disease Severity 
Follow-up Period for 
Patients who 
Discontinued Early 
from Trial Treatment 
Section deleted. 
In order to reduce the burden 
on the patients, the safety 
follow-up period has been 
replaced by 1 safety follow-
up visit. 
5.  TRIAL 
PROCEDURES 
5.6.  End of Study and Early Discontinuation (EoS/ED) 
Visit 
See summary above. 
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5.6.  End of Study and 
Early Discontinuation 
(EoS/ED) Visit 
In case of early discontinuation from the trial, the same 
assessments as scheduled for EoS (Day 365) must be 
performed as follows: 
• Assessments of disease severity. … (*) 
• …(*) 
 
(*) Only applicable for patients following Table 1. 
changed to 
5.5.  End of Part A, End of Study and Early 
Discontinuation (EoA/ED or EoS/ED) Visit 
In case of early discontinuation, the same assessments 
as scheduled for EoA (Day 365) or EoS (Day 1095 or 
when efgartigimod becomes commercially available or 
another option to access efgartigimod is available, 
whichever option comes first) must be performed as 
follows: 
For EoA/ED (Part A): 
• Assessments of disease severity. … 
• … 
For EoS/ED (Part B): 
• Assessments of disease severity (MG-ADL scale) 
should be performed prior to any other assessments 
except for the weight assessment. 
• Physical examination. 
• Weight. 
• Vital signs. 
• Clinical laboratory tests (local labs). 
• Urinalysis. 
• Urine pregnancy test (only for women of childbearing 
potential, see DEFINITION OF TERMS). 
• ADA (only in case of ED). 
• Review of concomitant medication. 
• Assess AEs, if any. 
 
Part B allows for freedom of 
changing therapy and there 
will be no restrictions on the 
type of therapy that can be 
used and no prohibited 
medications. This is because 
Part B will shift to a more 
real-life approach. 
6.  TRIAL 
TREATMENT 
6.8.  Prior Treatments 
and Concomitant 
Medications 
The following medications or treatments will lead to 
discontinuation from treatment during the trial as from 
SEB onwards: 
changed to 
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6.8.1.  Prohibited 
Medications during 
the Trial 
The following medications or treatments will lead to 
discontinuation from treatment during Part A of the 
trial as from SEB onwards: 
6.  TRIAL 
TREATMENT 
6.8.  Prior Treatments 
and Concomitant 
Medications 
6.8.1.  Prohibited 
Medications during 
the Trial 
The following text added: 
In Part B of the trial, a change of the type or 
dose/regimen of SoC (replacing, adding or removing 
SoC, or adjustment of the SoC dose and/or frequency) 
is allowed without restrictions, following standard 
clinical practice. 
PLEX, IVIg, immunoadsorption or use of a new type 
of corticosteroid or an increased dose of the current 
corticosteroids used as stand-alone therapy or in 
combination is also allowed in Part B. 
6.  TRIAL 
TREATMENT 
6.9.  Medical Care of 
Patients after End of 
Study 
Sentence deleted: 
… The Sponsor will not provide any additional care to 
these patients, neither will ARGX-113 be provided on 
a compassionate use program. 
The aim of the extension is to 
provide the patients with the 
chance to have access to 
efgartigimod while it is not 
yet commercially available or 
available through another 
patient program. Therefore 
this sentence is no longer 
valid. 
6.  TRIAL 
TREATMENT 
6.11.  Handling 
Missed Doses of 
Investigational 
Medicinal Product 
… according to the General Schedule of Assessments 
(Table 1). … 
changed to 
… according to the General Schedule of Assessments 
for Part A (Table 1) and for Part B (Table 2). … 
See summary above. 
7.  TRIAL 
ASSESSMENTS 
7.1.  Monitoring of 
Disease Severity 
Monitoring of disease severity will be assessed using 
MG-ADL and QMG. Both assessments have to be 
performed predose on all ARGX-113 infusion days and 
prior to any other assessment at each visit except for 
the assessment of weight (if applicable) and signing of 
the ICF at SEB. The MG-ADL scale needs to be 
performed prior to the QMG scale (Table 1).  
changed to 
Monitoring of disease severity will be assessed using 
MG-ADL (Part A and B) and QMG (Part A only). The 
assessments, where applicable, have to be performed 
predose on all ARGX-113 infusion days and prior to 
any other assessment at each visit, except for the 
assessment of weight (if applicable) and signing of the 
ICF at SEB. The MG-ADL scale needs to be 
performed prior to the QMG scale in Part A (Table 1). 
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7.  TRIAL 
ASSESSMENTS 
7.1.  Monitoring of 
Disease Severity 
7.1.1.  Myasthenia 
Gravis Activities of 
Daily Living 
... It evaluates the capacity to perform different 
activities of daily living such as talking, chewing, 
swallowing, breathing, brushing the teeth/combing the 
hair, or arising from the chair and it also assesses 
double vision and eyelid droop. 
changed to 
…It evaluates the capacity to perform different 
activities of daily living such as talking, chewing, 
swallowing, breathing, brushing the teeth/combing the 
hair, or rising from a chair and it also assesses double 
vision and eyelid droop. 
Sentence corrected. 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
Safety assessments will consist of monitoring and 
recording all AEs, pregnancies, suicidality assessment, 
safety laboratory testing, measurement of vital signs, 
ECGs, physical examinations; … 
changed to 
Safety assessments will consist of monitoring and 
recording all AEs, pregnancies, suicidality assessment 
(Part A only), safety laboratory testing, measurement 
of vital signs, ECGs (Part A only), physical 
examinations; … 
See summary above. 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.1.2.  Reporting of 
Adverse Events and 
Serious Adverse 
Events 
All AEs that occur during the trial from signature of 
the ICF until EoS are to be recorded on the appropriate 
AE pages (either ‘serious’ or ‘non-serious’) in the 
eCRF. … 
changed to 
All AEs that occur during the trial from signature of 
the ICF until the last study visit are to be recorded on 
the appropriate AE pages (either ‘serious’ or ‘non-
serious’) in the eCRF. 
Additional text added: 
All SAEs that are spontaneously reported within 30 
days after the last trial visit are to be collected and 
reported as previously described and all efforts should 
be made to follow-up until resolution. 
In order to comply with 
generally accepted safety 
pharmacovigilance 
guidelines, this paragraph has 
been added. 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.1.  Adverse Events 
7.2.1.4.  Follow-up of 
Adverse Events and 
Any AEs observed from signing the ICF to the EoS 
visit will be followed up to resolution, … 
… 
All SAEs that are spontaneously reported after the EoS 
visit are to be … 
changed to 
See summary above. 
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Serious Adverse 
Events 
Any AEs observed from signing the ICF to the last 
study visit will be followed up to resolution, … 
… 
All SAEs that are spontaneously reported after the last 
study visit are to be … 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.1.  Adverse Events 
7.2.1.5.  Reporting and 
Follow-up 
Requirements for 
Pregnancies 
7.2.1.5.1.  Pregnancies 
in Female Patients 
Urine pregnancy tests will be conducted and analyzed 
locally at all visits as detailed in the General Schedule 
of Assessments (Table 1). 
changed to 
Urine pregnancy tests will be conducted and analyzed 
locally at visits as detailed in the General Schedule of 
Assessments for Part A (Table 1) and for Part B 
(Table 2). Results will be recorded in the eCRF. 
•  The patient should have EoT assessments. 
•  All assessments for EoT (see Sections 4.4.2 and 5.4) 
must be performed unless contraindicated by 
pregnancy … 
changed to 
•  The patient should have the planned ED assessments. 
•  All planned assessments (see Sections 4.4.2 and 5.4) 
must be performed unless contraindicated by 
pregnancy … 
There is no End of Treatment 
visit. 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.2.  Clinical 
Laboratory 
Evaluations 
Blood and urine samples for determination of clinical 
chemistry, hematology, urinalysis, PD, and ADA will 
be analyzed at a central lab as indicated in the General 
Schedule of Assessments (Table 1) and Appendix 3. 
Patients need to be fasting for at least 8 hours prior to 
the sampling for clinical laboratory tests as from SEB 
up to EoS. Patients need to be fasting for at least 8 
hours prior to the sampling for clinical laboratory tests 
as from SEB up to EoS. 
… 
For all patients of childbearing potential, a urine 
pregnancy test will be conducted and analyzed locally 
at the site (on the urine samples taken for urinalysis) at 
all visits (Table 1). 
The estimated total maximum blood volume needed for 
a patient during the trial (when completing the trial up 
until the last visit) is between 170 mL for a patient who 
receives 1 Treatment Period only and 362 mL for a 
patient who receives a maximum of 6 Treatment 
Periods. 
See summary above. 
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Besides the urine pregnancy test, which will be 
conducted and analyzed locally, all samples will be 
analyzed centrally. 
changed to 
In Part A blood and urine samples for determination of 
clinical chemistry, hematology and urinalysis will be 
analyzed at a central laboratory. PD and ADA will be 
analyzed at a specialty laboratory as indicated in the 
General Schedule of Assessments for Part A (Table 1) 
and Appendix 3. Patients need to be fasting for at least 
8 hours prior to the sampling for clinical laboratory 
tests as from SEB up to EoA. 
In Part B, blood and urine samples for determination of 
clinical chemistry, hematology and urinalysis will be 
analyzed at local laboratories and results will not be 
recorded in the eCRF. Blood samples for ADA will be 
analyzed at a specialty laboratory as indicated in the 
General Schedule of Assessments for Part B (Table 2) 
and Appendix 3. 
… 
For all patients of childbearing potential, a urine 
pregnancy test will be conducted and analyzed locally 
at the site (on the urine samples taken for urinalysis, if 
applicable) at all visits in Part  A (Table 1) and at 
Visit 1 and 4 of each Treatment Period, at ITPE visits, 
at EoS/ED and at the discretion of the Investigator in 
Part B (Table 2). 
The estimated total maximum blood volume needed for 
a patient during Part A of the trial (when completing 
the trial up until the last visit) is between 170 mL for a 
patient who receives 1 Treatment Period only and 362 
mL for a patient who receives a maximum of 6 
Treatment Periods. The estimated total maximum 
blood volume needed for a patient during Part B of the 
trial (when completing the trial up until the last visit) is 
between 24 mL for a patient who receives 1 Treatment 
Period only and 100 mL for a patient who receives 6 
Treatment Periods. 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.3.  Vital Signs, 
Physical Examination, 
and ECG 
Assessment of vital signs (supine blood pressure, heart 
rate, and body temperature), physical examination and 
ECG will be performed at the time points indicated in 
the General Schedule of Assessments (Table 1) 
(predose at dosing days). 
A 12-lead ECG will be recorded locally as per local 
regulations … 
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Section 
Change 
Rationale 
changed to 
Assessment of vital signs (supine blood pressure, heart 
rate, and body temperature), physical examination and 
ECG (Part A only) will be performed at the time points 
indicated in the General Schedule of Assessments for 
Part A (Table 1) and for Part B (Table 2) (predose at 
dosing days). 
Weight will be measured at SEB, at the EoS/ED visit, 
and can be repeated … 
changed to 
Weight will be measured at SEB, at the EoA/ED visit, 
at Visit 1 of Part B, at the EoS/ED visit, and can be 
repeated … 
A 12-lead ECG will be recorded locally (only for Part 
A) as per local regulations … 
7.  TRIAL 
ASSESSMENTS 
7.2.  Safety 
7.2.4.  Suicidality 
Assessment 
As is recommended …suicidal ideation and behavior 
will be included in this clinical trial. 
changed to 
As is recommended … suicidal ideation and behavior 
will be included in this clinical trial (Part A only). 
7.  TRIAL 
ASSESSMENTS 
7.3.  
Pharmacodynamics 
The PD markers (total IgG and IgG subtypes [IgG1, 
IgG2, IgG3 and IgG4], and … 
changed to 
In Part A, the PD markers (total IgG and IgG subtypes 
[IgG1, IgG2, IgG3 and IgG4], and … 
7.  TRIAL 
ASSESSMENTS 
7.4.  Anti-Drug 
Antibodies 
Blood samples to assess ADA will be collected 
predose at the time points as indicated in Table 1. At 
Baseline (SEB and TPnB), confirmatory and titer 
analysis … 
changed to 
Blood samples to assess ADA will be collected 
predose at the time points as indicated in Table 1 and 
Table 2. At Baseline (SEB, TPnB and TPEnB), 
confirmatory and titer analysis … 
8.  STATISTICS 
Wording added: 
Endpoints will be summarized by treatment (as 
received in ARGX-113-1704). 
Wording added for 
clarification. 
8.  STATISTICS 
A tabular presentation of the patient disposition will be 
provided. It will include the number of patients 
Wording corrected; statistical 
analysis will be carried out 
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Section 
Change 
Rationale 
8.3.  Patient 
Disposition, 
Characteristics and 
Concomitant 
Medication 
screened, enrolled, completed (per Treatment Period), 
… 
… 
A list of protocol violations will be identified and 
discussed with the Investigator to categorize as major 
or minor and the same will be reported. 
… 
Use of concomitant medication will be summarized by 
treatment with frequency and percentage. All 
concomitant medications used will be listed. 
changed to 
A tabular presentation of the patient disposition will be 
provided. It will include the number of patients 
enrolled, completed (by cycle), … 
… 
Use of concomitant medication will be summarized 
with frequency and percentage. All concomitant 
medications used will be listed. 
per cycle (Treatment Period + 
Intertreatment Period) not 
just per Treatment Period. 
The protocol violation 
process is not relevant for the 
statistics in this section. 
8.4.  Statistical 
Methods 
8.4.  Statistical 
Methods 
8.4.1.  Primary and 
Secondary Endpoint 
Analyses 
Frequency tables will be made for all binary variables, 
i.e., AEs, for all available time points, by Treatment 
Period (including Intertreatment Period) and overall. 
Summary statistics will be provided for the continuous 
endpoints (e.g., laboratory values, vital signs, ECGs) in 
terms of absolute values and changes from SEB (for 1-
year assessment), and changes from Treatment Period 
Baseline (TP1B), at each Treatment Period (including 
Intertreatment Period),by cycle and available time 
points. 
changed to 
Frequency tables will be made for all binary variables, 
i.e., AEs, by cycle and overall. 
Summary statistics will be provided for the continuous 
endpoints (e.g., laboratory values, vital signs, ECGs) in 
terms of absolute values and changes from TP1B by 
cycle and available time points. 
Corrected to reflect that AEs 
are not reported by timepoint 
and that for safety endpoints 
only changes from the 
treatment period baseline of 
the first cycle will be 
summarized as patients might 
start the study with an 
intertreatment period. 
8.  STATISTICS 
8.4.  Statistical 
Methods 
8.4.2  Tertiary 
Endpoint Analyses 
The tertiary endpoints will be analyzed in a descriptive 
manner.  
Summary statistics will be provided for the continuous 
endpoints (e.g., total MD-ADL score, total QMG 
score, levels of total IgG and subtypes, anti-
AChR/anti-MuSK antibodies) in terms of absolute 
values and changes from SEB (for 1-year assessment) 
Corrected to reflect that 
changes from the treatment 
period baseline of the first 
cycle will be summarized 
(instead of changes from 
SEB) as patients might start 
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Section 
Change 
Rationale 
and changes from TPB, at each Treatment Period 
(including Intertreatment Period), and available time 
points. For levels of total IgG and subtypes and also 
anti-AChR/anti-MuSK antibodies, the percentage 
change from SEB and from TPB will also be 
presented. Every 30 days’ percent change compared to 
SEB will be calculated. 
Frequency tables will be made for incidence of ADA to 
ARGX-113 every 30 days in patients who are (re-
)treated with ARGX-113, at SEB, at Visits 1 and 4 of 
each Treatment Period, and at the EoS visit. In 
addition, within each Treatment Period, the proportion 
of patients treated with ARGX-113 that present ADA’s 
over all time points will be calculated together with 
95% confidence interval (CI) using Clopper-Pearson 
exact method. 
Interim analyses might be performed to support 
questions for authorities and/or submissions. 
changed to 
The tertiary endpoints will be summarized 
descriptively.  
Summary statistics will be provided for the continuous 
endpoints (e.g., total MD-ADL score, total QMG 
score, levels of total IgG and subtypes, anti-
AChR/anti-MuSK antibodies) in terms of absolute 
values, changes from TP1B or changes from TPnB, by 
cycle and available time points. For levels of total IgG 
and subtypes and also anti-AChR/anti-MuSK 
antibodies, the percentage change from TP1B and from 
TPnB will also be presented. 
Frequency tables will be made for incidence and 
prevalence of ADA to ARGX-113. 
8.5.  Interim Analyses 
Interim analyses might be performed to support 
questions for authorities and/or submissions. 
the study with an 
intertreatment period. 
 
ADA will also be 
summarized as is consistent 
with the literature. 
 
An extra section has been 
added for interim analyses as 
these do not belong with the 
tertiary endpoints. 
Appendix 3:  
Laboratory 
Evaluations 
Note: All blood and urine samples will be collected 
locally (predose on dosing days) and analyzed 
centrally. 
changed to 
Note: For Part A, all blood and urine samples will be 
collected locally (predose on dosing days) and 
analyzed at a central or specialty laboratory. For Part 
B, blood and urine samples for clinical chemistry, 
hematology and urinalysis will be analyzed locally, 
Given the long time frame of 
the extension and the option 
of unscheduled visits being 
carried out at the request of 
the Investigator, the more 
flexible option of working 
with a local laboratory has 
been chosen over the central 
laboratory structure. 
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4.1. Summary of Trial 
Design 
ROLL-OVER 
(serious) adverse event ([S]AE) that might jeopardize 
the safety of the patient in that trial will not be offered 
the option to roll over into this trial.” 
changed to 
“Patients who discontinued early from trial ARGX-
113-1704 or discontinued early from randomized 
treatment for rescue or pregnancy reasons or for a 
serious adverse event (SAE) that is likely to result in a 
life-threatening situation or pose a serious safety risk in 
that trial will not be offered the option to roll over into 
this trial.” 
serious safety risk in order to 
have the patient discontinued. 
SYNOPSIS 
(RE-)TREATMENT 
4.1. Summary of Trial 
Design 
(RE-)TREATMENT 
 
“Each patient may start a (new) Treatment Period with 
ARGX-113 when all the following criteria apply: 
The patient has completed the previous Treatment 
Period; AND” 
changed to: 
“Each patient will start a (new) Treatment Period with 
ARGX-113 when all the following criteria apply: 
The patient has completed the previous Treatment 
Period (i.e. after Visit 4); AND” 
Wording adjusted for 
clarification. 
SYNOPSIS 
(RE-)TREATMENT 
4.1. Summary of Trial 
Design 
(RE-)TREATMENT 
“Patients who are in need of an additional treatment 
but who are not eligible to receive (re-)treatment for 
reasons listed here will remain in the trial to receive 
appropriate alternative MG treatment.” 
changed to: 
“Patients who are in need of an additional treatment 
but who are not eligible to receive (re-)treatment for 
reasons listed here will remain in the trial to receive 
appropriate alternative MG treatment see Appendix 5  
and Appendix 6.” 
Wording adjusted for 
clarification. 
 
“Patients who fail to respond to ARGX-113 ...” 
changed to: 
“Patients who show a treatment failure to ARGX-113 
...” 
 
SYNOPSIS 
STANDARD of 
CARE (SoC) 
4.1. Summary of Trial 
Design 
STANDARD OF 
CARE (SoC) 
Addition of the following sentences: 
“Permitted SoC for MG treatment under this protocol 
include NSIDs (e.g., azathioprine, methotrexate, 
cyclosporine, tacrolimus, mycophenolate mofetil, and 
cyclophosphamide), steroids, as well as 
acetylcholinesterase (AChE) inhibitors.” 
Sentences added for extra 
clarification. 
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“In case these medications are taken for another 
indication than MG, same conditions apply.” 
“Administration of AChE inhibitors must be halted for 
at least 12 hours prior to performing the QMG 
assessment. Following this requirement, this possible 
temporary change in dosing regimen of AChE 
inhibitors will not be considered as a change in SoC.” 
SYNOPSIS 
RESCUE THERAPY 
4.1. Summary of Trial 
Design 
RESCUE THERAPY 
“If necessary, patients may receive rescue therapy, 
which will be limited to plasma exchange (PLEX), ...” 
changed to: 
“Rescue therapy, will be limited to plasma exchange 
(PLEX, ...” 
Wording adjusted to enhance 
clarification. 
 
“In situations where rescue therapy is given, patients 
will be discontinued early from trial treatment.” 
changed to 
“In situations where the treatments as listed above are 
given under the protocol-defined rescue criteria, 
patients will be discontinued early from trial 
treatment.” 
 
SYNOPSIS 
Inclusion Criteria 
4.3.1 Inclusion 
Criteria 
Criterion no. 3: 
“Note: AChE inhibitors must be held for at least …” 
changed to 
“Note: AChE inhibitors must be halted for at least …” 
Deletion of the following sentence: 
“Following this requirement, this possible temporary 
change in dosing regimen of AChE inhibitors will not 
be considered as a change in SoC.” 
Administrative change. 
SYNOPSIS 
Exclusion Criteria 
4.3.2 Exclusion 
Criteria 
Criterion no. 5: 
“Patients with known autoimmune disease other than 
MG (i.e., autoimmune thyroiditis) that …” 
changed to 
“Patients with known autoimmune disease other than 
MG (for example autoimmune thyroiditis, rheumatoid 
arthritis, …) that …” 
Typo/wrong use of “i.e.” was 
corrected, additional example 
provided. 
SYNOPSIS 
Exclusion Criteria 
4.3.2 Exclusion 
Criteria 
New exclusion criterion added: 
7. “Patients with known medical history of 
hypersensitivity to any of the ingredients of ARGX-
113.” 
Updated in order to align 
with CTP ARGX-113-1705 
Japan-specific version 1.1 
which was updated upon 
request of PMDA. 
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Table 1 General 
Schedule of 
Assessments
Assessment “Weight”
changed to
“Weight and Height”
Updated in order to align 
with ARGX-113-1705 SAP.
Addition of the following sentence in footnote “i”
“Height will be measured at SEB.”
Added for completeness.
“d During the UNS visit, additional assessments can be 
performed at …”
changed to
“d During the UNS visit, additional assessments as 
indicated in the SoA can be performed at …”
Administrative change.
DEFINITION OF 
TERMS
Childbearing potential:
Deletion of the following sentence:
“Determination of FSH levels can be used to confirm 
postmenopausal status in amenorrheic patients not on 
hormonal replacement therapy if the test result is 
within the postmenopausal range per the central 
laboratory performed in study ARGX-113-1704.”
Correction.
4.4.2. Early 
Discontinuation from 
Trial Treatment
“
Patient develops an (S)AE that might jeopardize 
the safety of the patient.”
changed to:
“
Patient develops an SAE that is likely to result in a 
life-threatening situation or pose a serious safety risk.”
Change of wording to clarify 
that there needs to be a 
serious safety risk in order to 
have the patient discontinued.
4.5. Protocol 
Deviations
“The Investigator should not implement any deviation 
from, or changes of the protocol without agreement by 
the Sponsor and prior review and documented approval 
from the Institutional Review Board/Independent 
Ethics Committee (IRB/IEC), except …”
changed to
“The Investigator should not implement any deviation 
from, or changes of the protocol without agreement by 
the Sponsor and prior review and documented approval 
from the Institutional Review Board/Independent 
Ethics Committee (IRB/IEC) of an amendment from 
the IRB/IEC and Regulatory Authority as per local 
regulation, except ...”
Administrative change.
4.7. End of Trial 
Definition
The following was added:
“4.7. End of Trial Definition
End of trial is defined as last patient last visit.”
Added for completeness (was 
missing in the previous 
version).
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5.1. Informed Consent 
and Roll-Over Visit
“
Weight”
changed to
“
Weight and height”
6.8. Prior Treatments
and Concomitant 
Medications
Addition of the following sentence:
“Vaccines (except for live/live-attenuated vaccines) 
will be allowed during the trial when administered at 
least 48 hours pre-infusion or 48 hours postinfusion of 
IMP.”
For patient safety, allowing 
for vaccines to be 
administered according to 
common clinical practice and 
to reduce the risk of 
confusing vaccination-related 
adverse events (such as fever) 
with IMP-infusion related 
adverse events.
6.8.1. Prohibited 
Medications during 
the Trial
“The following medications or treatments will not be 
permitted as from signing the ICF during the trial:”
changed to
“The following medications or treatments will lead to 
discontinuation from treatment during the trial as from 
SEB onwards:”
Wording updated for 
clarification.
6.8.1. Prohibited 
Medications during 
the Trial
“an increase of the dose/frequency of SoC, even if used 
for indications other than MG”
changed to
“a change in the type or an increase of the 
dose/frequency of SoC, even if used for indications 
other than MG”
Clarify that patients are not to 
start treatment with a new 
SoC
“Vaccines”
changed to
“Live/live-attenuated vaccines”
For patient safety, allowing 
for vaccines to be 
administered according to 
common clinical practice and 
to reduce the risk of 
confusing vaccination-related 
adverse events (such as fever) 
with IMP-infusion related 
adverse events.
“Rescue therapy”
changed to
“Rescue therapy when used in patients who meet the 
criteria to be rescued”
Wording added for 
clarification.
Additional bullet:
“
Use of PLEX or immunoadsorption more than 
once during the study period”
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6.8.2. Rescue Therapy 
First sentence (“If necessary, patients may receive 
rescue therapy if their gMG deteriorates.”) deleted. 
To align with the 
corresponding section in the 
Synopsis, Section 4.1, and 
Section 6.8.1. 
 
“In situations where rescue therapy is given, patients 
will be discontinued early from trial treatment.” 
changed to 
“In situations where the treatments as listed above are 
given under the protocol-defined rescue criteria, 
patients will be discontinued early from the trial 
treatment.” 
 
6.11. Handling Missed 
Doses of 
Investigational 
Medicinal Product 
“In case a dose needs to be delayed for more than 5 
days, …” 
changed to 
“In case a dose needs to be delayed for more than 3 
days, …” 
Correction. 
7.1.2. Quantitative 
Myasthenia Gravis 
End of section, one but last sentence: 
“…dynamometer, and is based on physician’s 
examination.” 
changed to 
“…dynamometer, and is based on the trained rater’s 
examination.” 
Updated because the rater 
needs to be a trained person, 
but not necessarily a 
physician. 
7.2.1.1. Adverse 
Events of Special 
Interest 
New section added: 
“An AESI (serious or non-serious, related or not 
related) is an event of scientific and medical concern 
specific to the sponsor’s product or program. 
ARGX-113 treatment induces reductions in IgG levels, 
and there is a potential risk for infections associated 
with the low IgG levels. As such, any infection will be 
considered AESI in this trial. Further characterizing 
information will be collected in the eCRF, such as: 
location of infection, relationship to underlying 
condition, medical history and concomitant 
medication, reoccurrence of previous infection, 
previous rescue therapy, any confirmatory procedure, 
culture or urgent medical intervention.” 
Since the mechanism of 
action of ARGX-113 induces 
reductions in IgG levels there 
is a potential of infection risk. 
Therefore, infections will be 
captured as AESIs, in order 
to collect the data in a 
systematic way. 
7.2.1.4. Follow-up of 
Adverse Events and 
Serious Adverse 
Events 
Second paragraph: 
“Every effort should be made to follow all AEs …” 
changed to 
“Every effort should be made to follow all (S)AEs …” 
Table deleted and text 
updated to clarify that all 
SAEs are to be followed-up 
until resolution. 
 
Sentence referring to Table 3 and Table 3 deleted 
 
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7.2.1.5.1 Pregnancies 
in Female Patients 
The following sentence has been added: 
“If required by local regulations, the female participant 
will be requested to sign a separate pregnancy ICF.” 
Added for completeness. 
7.2.2. Clinical 
Laboratory 
Evaluations 
“Refer to Appendix 4 for the addresses of the 
laboratories used for sample analyses.” 
changed to 
“Refer to Appendix 4 for the addresses of the 
laboratories used for sample analyses and storage.” 
Updated in order to align 
with CTP ARGX-113-1705 
The Netherlands-specific 
version 1.2. 
7.3. 
Pharmacodynamics 
“(PD)” was added to the section title. 
Added for completeness. 
7.4. Anti-Drug 
Antibodies 
“(ADA)” was added to the section title. 
 
10.2. Ethical Conduct 
of the Trial 
The paragraph: “This trial will be conducted and the 
informed consent will be obtained according to the 
ethical principles stated in the Declaration of Helsinki 
(2008), the applicable guidelines for GCP, or the 
applicable drug and data protection laws and 
regulations of the countries where the trial will be 
conducted.” 
was updated to: 
“This trial will be conducted and the informed consent 
will be obtained according to the ethical principles 
stated in the Declaration of Helsinki (2013), the 
applicable guidelines for GCP, or the applicable drug 
and data protection laws and regulations of the 
countries where the trial will be conducted. 
To comply with the Declaration of Helsinki (2013), 
argenx is assessing the appropriateness and possibility 
of making the study drug available for clinical study 
participants post-trial.” 
Updated in order to align 
with CTP ARGX-113-1704 
The Netherlands-specific 
amendment version 1.1. upon 
request of the Ethics 
Committee of The 
Netherlands. 
11.1. Data Handling 
and Record Keeping 
First sentence: 
“It is the Investigator’s responsibility to maintain 
essential trial documents (including regulatory 
documents, eCRFs, signed patient ICFs, source 
documents, …” 
changed to 
“It is the Investigator’s responsibility to maintain 
essential trial documents (including records and 
documents pertaining to the conduct of this trial and 
the distribution of IMP, regulatory documents, eCRFs, 
signed patient ICFs, laboratory test results, IMP 
inventory records, source documents, …” 
Updated to avoid duplication 
of information. 
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The following sentence was added to the end of the 
first paragraph: 
“The Sponsor will notify the Principal Investigator of 
these events.” 
 
11.1. Data Handling 
and Record Keeping 
Third paragraph ("The United States (US) Food and 
Drug Administration (FDA) regulations … the 
Principal Investigator of these events.”) deleted. 
Updated to avoid duplication 
of information. 
Appendix 3
 
Laboratory 
Evaluations 
Other: 
“follicle-stimulating hormone (FSH) test” deleted 
Correction (FSH test does not 
need to be redone in this 
trial). 
Appendix 4
 
Administrative 
Structure 
Clinical Laboratories: 
“Asia 
Covance Asia 
Pte Ltd1 International Business Park 
#01-01 The Synergy 
Singapore 609917” 
deleted 
This Covance Lab is not 
involved anymore in the trial 
since Korea is dropped from 
country mix. 
 
“Analysis of Pharmacokinetics-Pharmacodynamics 
(PK-PD), Anti-Drug Antibodies (ADA)” 
changed to 
“Analysis of Pharmacodynamics (PD), Anti-Drug 
Antibodies (ADA)” 
Correction (PK is not 
performed in this trial). 
 
Addition of the following: 
“Long-Term Storage of Pharmacodynamics (PD), 
Anti-Drug Antibodies (ADA) 
Brooks Life Science, Biostorage Technologies GmbH 
Im Leuschnerpark 1b 
64347 Griesheim 
Germany” 
Updated in order to align 
with CTP ARGX-113-1705 
The Netherlands-specific 
version 1.2. 
Appendix 5 Decision 
Tree for re-Treatment 
(Part A) 
Figure added. 
Added for clarification. 
Appendix 6 Decision 
Tree for re-Treatment 
(Part B) 
Figure added. 
 
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APPENDIX 8: Temporary Changes to Study Procedures in ARGX-113-1705 
Related to the COVID-19 Pandemic 
Introduction 
As the COVID-19 pandemic poses issues for both sites and patients and presents unprecedented 
challenges in uncharted territory, this crisis prompted the sponsor to perform a critical review of 
both efgartigimod administration and changes needed to the study in order to safeguard patient 
safety, while still being able to gather additional data.  
The risk/benefit, safety profile, guidance for site conduct in terms of visits and assessments, as 
well as data entry, and potential changes in the Schedule of Assessments are included below. 
Safety of Efgartigimod: Mechanism of Action, Pharmacodynamics and Risk/Benefit in  
Patient Safety 
Efgartigimod administration results in a targeted reduction in levels of all IgG subtypes. 
However, and more importantly, it does not impact levels of other immunoglobulin isotypes, 
such as IgA and IgM. Other elements of the immune system are not impacted by efgartigimod 
treatment. 
Efgartigimod induces a targeted reduction of IgG levels, without impacting IgG production. The 
maximum mean reduction in total IgG is approximately 70%; therefore, residual IgG and other 
immunoglobulin levels remain constant during treatment. It is therefore anticipated that patients 
can mount an immune response. In support of this, experiments in FcRn knockout animals and in 
animals treated with FcRn antagonist demonstrated that a specific immune response was 
obtained following an antigen trigger, albeit with reduced (antigen-specific) IgG titers. 
Additionally, after ceasing efgartigimod treatment, IgG recycling returns and total IgG levels 
increase and return to baseline levels within a few weeks. 
Looking at administration in humans, efgartigimod treatment at doses ≥10 mg/kg have been 
administered to more than 120 healthy volunteers and patients with generalized myasthenia 
gravis (gMG), immune thrombocytopenia, and pemphigus in studies carried out prior to phase 3 
studies. No general or infection-related safety concerns were identified.  
The phase 3 ADAPT gMG study enrolled 167 patients and data will be available in mid-2020. 
An active assessment of adverse event reports during the study remains ongoing. Although the 
phase 3 ADAPT data are blinded, no safety concern has been identified to date. 
Available data from trials of other FcRn antagonists have not identified any increased risk of 
infection. 
 
ADAPT/ADAPT+: Pre-existing Safety Measures and Changes to Be Implemented in the 
Current Situation 
The phase 3 ADAPT study implements multiple layers of safety measures and reporting. 
Efgartigimod is administered in treatment cycles, in which 4-weekly infusions are followed by 
additional treatment cycles that are administered according to clinical need. Therefore, during the 
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follow-up period after each treatment cycle, FcRn recycling resumes and IgG levels begin to 
increase. 
The protocol gives guidance to temporarily or permanently discontinue treatment when the 
patient has signs of clinically significant of bacterial, viral, or fungal infection, in order to treat 
the underlying condition. The treatment can be initiated at a later time once the clinically 
significant infection has been deemed resolved. A Treatment Period can be considered as 
interrupted if the patient is not able to visit the site for more than 1 visit. In such cases, a new 
Treatment Period can be initiated at a later date. 
Additionally, any case of infection is regarded as an adverse event of special interest (AESI) and 
is subject to structured safety reporting with standardized questions in the eCRF. 
The current COVID-19 situation warrants new measures to be introduced for patient safety. 
These measures will allow patients to be evaluated remotely if/when quarantine is imposed. For 
example, any remaining visits in an interrupted Treatment Period, may be performed remotely, in 
cases where the patient is not allowed or cannot physically visit the site. These measures respect 
both patient safety and local guidance, as well as allowing basic safety data to be collected. 
The assessments identified for telephone assessment visits are highlighted with the use of bold 
italics in the existing Schedule of Assessments for Part A in Table 1 and for Part B in Table 2. 
Guidance on the execution of these visits and assessments is given below. 
By providing a structured back-up plan, we aim to mitigate the risks of the COVID-19 pandemic, 
while still respecting both patient safety and collection of safety data and remaining compliant 
with GCP. 
 
Visits with the possibility of remote assessment by telephone: 
TPxV2, TPExV2, TPxV3, TPExV3, TPxV4, TPExV4, ITPxVx, ITPExVx, EoA, EoS, ED, and 
UNS. See the Schedule of Assessments for Part A (Table 1) and for Part B (Table 2). 
Treatment Period visits will be replaced by telephone assessment visits during the current 
COVID-19 situation when the Treatment Period is considered interrupted.  
 
Mandatory physical visits: 
Initiating a new Treatment Period can only be done when the patient is physically on site. 
 
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Guidance to Sites in Case of Suspected COVID-19 in Patients 
As sponsor we want to emphasize and highlight the need to follow the guidance issued by local 
authorities. Wherever guidance is unclear, or if no specific guidance is available, argenx will 
recommend to either postpone the visit if possible or evaluate the need for telephone assessments 
to replace a physical visit. 
The site should contact the patient prior to each visit, and conduct the following COVID-19 
assessments: 
 
1. Does the patient have symptoms, such as cough, fever, muscle pain, shortness of breath*? 
- If NO: Go to Questions 2 and 3. 
- If YES: 
• The patient should be tested for COVID-19:  
The investigator needs to document a positive COVID-19 test as an AESI. The anonymized 
result needs to be sent to the sponsor for filing. If COVID-19 safety measures are stopped 
according to local regulations, COVID-19 tests should continue to be performed and the 
results sent to the sponsor. 
*Shortness of breath includes an otherwise unexplained deterioration in the patient’s MG-
ADL score for breathing. In cases where the MG-ADL score for breathing is 2 or 3 additional 
COVID-19 testing should be carried out. The exception to this is when a patient has an MG-
ADL score for breathing of 2 at baseline. In such cases the patient should only be tested when 
the MG-ADL score for breathing returns to 2 after previous improvement or when it 
deteriorates to 3. 
The visit will only take place once the patient has a negative test for COVID-19. The planned 
visit may need to be rescheduled or can be replaced by a telephone assessment visit. If the 
patient was in a treatment cycle, the treatment will have to be interrupted. A new treatment 
cycle may be initiated later. Remaining visits in the Treatment Period can be performed 
as telephone assessment visits. 
• If the patient is tested and found to be COVID-19 negative:  
The patient can come to the next visit as scheduled. Follow-up of the patient should be done 
according to the protocol (decision to be taken if treatment can be given or is to be 
postponed). 
• If the patient is tested and found to be COVID-19 positive:  
The patient can only come to the site once he/she has a negative test for COVID-19, and so 
the planned visit may need to be rescheduled or replaced by a telephone assessment visit. If 
the patient was in a treatment cycle, the treatment will have to be interrupted. A new 
treatment cycle may be initiated later. The remaining visits in the Treatment Period can be 
replaced by telephone assessment visits. 
 
2. The patient has no Corona-like symptoms and is not aware of any contact he/she may have had 
with someone who tested positive for COVID-19:  
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• The visit can proceed as planned. If the patient cannot physically come to the clinic due to the 
local COVID-19 situation, the visit can be replaced by a telephone assessment visit. 
 
3. The patient has no Corona-like symptoms but has been in contact with someone who tested 
positive for Corona virus: 
• If the contact was 14 days or longer before the study visit => the visit can go ahead as planned. 
If the patient cannot physically come to the clinic due to the local COVID-19 situation, the visit 
can be replaced by a telephone assessment visit. 
• If the contact was less than 14 days before the study visit => the visit needs to be rescheduled at 
least 14 days after the contact occurred or be replaced by a telephone assessment visit. 
 
How to: Information related to study procedures and data collection 
The assessments deemed suitable for telephone consultation are: 
x Re-consenting where warranted, MG-ADL, Adverse Event and Concomitant 
Medication questioning.  
Since QMG needs quantification by the physician, using specific equipment, such as a 
dynamometer and spirometer, this assessment is not deemed suitable for telephone assessment.  
Telephone consultation will allow safety data to be collected and to check on the patient’s well-
being, while the derived MG-ADL score may give an indication of the need for another treatment 
with efgartigimod. 
Re-consenting with the updated ICF, or consent to Part B of the ADAPT+ study can be done 
remotely in view of the COVID-19 situation.  
Options for consent might entail: 
x physical signature by sending the ICF to the patient by courier and having a phone call 
with the patient, then having the signed document sent back to the site. 
x phone call with the patient, asking for email confirmation to corroborate verbal 
consent. 
x organize a conference call or video call together with the patient and impartial 
witness, where needed. 
x if no phone call or video call is possible, email documented consent. 
Depending on regional requirements the options can be limited, after consultation with the 
relevant IRB/IEC and/or regulatory authority. 
Data collected during a telephone assessment visit can be entered into the e-CRF pages of the 
corresponding “missed” visit. Enter the date of the phone call as the “date of visit” and enter the 
data obtained in the applicable CRF pages. For the assessments that are not performed, answer 
“no” to the question if the assessment was made in the respective forms. Add “COVID-19 
telephone” in the comment section of the CRF. 
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If you are not able to contact the patient, inactivate the full study visit in the CRF and confirm the 
missing visit in the comments section as “COVID-19.” 
Other than conducting telephone assessments, there may be other changes in the current practice 
on site. Halting spirometry in COVID-19 patients may be required, or only allowing use of a 
dedicated spirometry device (for contamination reasons).  There can be a temporary halt in 
performing this assessment, or conducting a partial assessment is also permitted. 
In order to give a clear overview of protocol deviations related to the specific COVID-19 
situation, dedicated protocol deviations with the COVID-19 label have been created to which any 
missed visit or assessment can be attributed. 
 
APPENDIX 9: Contraceptive and Barrier Guidance 
Definitions 
Woman of childbearing potential 
A woman is considered to be of childbearing potential unless she is either:  
a. Postmenopausal: A postmenopausal state is defined by continuous amenorrhea 
for at least 1 year without an alternative medical cause with a follicle-
stimulating hormone (FSH) measurement of >40 IU/L. A historical 
pretreatment FSH measurement of >40 IU/L is accepted as proof of a 
postmenopausal state for women on hormone replacement therapy 
b. Surgically sterilized: Women who have had a documented permanent 
sterilization procedure (ie, hysterectomy, bilateral salpingectomy, or bilateral 
oophorectomy) 
Contraception Guidance 
Female Contraception for Women of Childbearing Potential 
Women of childbearing potential must use a highly effective or acceptable method of 
contraception which should be maintained at minimum until 90 days after last dose of IMP. 
The following methods are considered highly effective methods of contraception: 
1. Combined (estrogen and progestogen containing) hormonal contraception 
associated with inhibition of ovulation 
 Oral 
 Intravaginal 
 Transdermal 
2. Progestogen-only hormonal contraception associated with inhibition of ovulation 
 Oral 
 Injectable 
 Implantable 
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3. Intrauterine device (IUD) 
4. Intrauterine hormone-releasing system (IUS) 
5. Bilateral tubal occlusion 
6. Vasectomized partner 
7. Sexual abstinence 
The following methods are considered acceptable methods of contraception: 
1. Progestogen-only oral hormonal contraception in which inhibition of ovulation is 
not the primary mode of action 
a. Oral 
b. Injectable 
c. Implantable 
2. Male or female condom with or without spermicide 
3. Cap, diaphragm, or sponge with spermicide 
Male Contraception 
An acceptable method of contraception is a condom. 
 
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