A Long-Term, Single-Arm, Open-label, Multicenter Phase 3 Study to Evaluate the Safety and Tolerability of Multiple Subcutaneous Injections of Efgartigimod PH20 SC in Patients With Generalized Myasthenia Gravis
Phase: PHASE3
Conditions: Generalized Myasthenia Gravis
Sponsor: argenx

Clinical Study Protocol ARGX-113-2002 v3.0 
 02 Feb 2023 
Efgartigimod PH20 SC 
argenx BV 
Confidential 
Page 1 of 120 
 
PROTOCOL: ARGX-113-2002 
PROTOCOL TITLE:  
A Long-term, Single-Arm, Open-label, Multicenter Phase 3 Study to Evaluate the Safety and 
Tolerability of Multiple Subcutaneous Injections of Efgartigimod PH20 SC in Patients With 
Generalized Myasthenia Gravis 
SHORT TITLE:  
Evaluating the Long-term Safety and Tolerability of Efgartigimod PH20 SC Administered 
Subcutaneously in Patients With Generalized Myasthenia Gravis 
STUDY PHASE:  
3 
ACRONYM:  
ADAPTSC+ 
COMPOUND:  
Efgartigimod 
REGULATORY AGENCY IDENTIFIER NUMBER(S): 
Registry 
ID 
IND 
 
EUDRACT 
2020-004086-38 
SPONSOR NAME:  
argenx BV 
System Version: 1.0, Status: Approved, Document ID: VV-TMF-88586

Clinical Study Protocol ARGX-113-2002 v3.0 
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Efgartigimod PH20 SC 
argenx BV 
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LEGAL REGISTERED ADDRESS:  
Industriepark Zwijnaarde 7 
9052 Zwijnaarde (Ghent) 
Belgium 
Phone: +32 9 310 34 00 
Fax: +32 9 310 34 99 
 
PRINCIPAL/ 
COORDINATING 
INVESTIGATOR: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
The information contained in this medium is the property of argenx BV and/or its subsidiaries 
(jointly “argenx”) and is confidential and proprietary. Without prior authorization from argenx, 
information contained herein may not be used, reproduced, divulged, published, or otherwise 
disclosed to anyone. 
 
 
System Version: 1.0, Status: Approved, Document ID: VV-TMF-88586

Clinical Study Protocol ARGX-113-2002 v3.0 
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Efgartigimod PH20 SC 
argenx BV 
Confidential 
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SIGNATURE OF THE SPONSOR 
Protocol Title: 
A Long-term, Single-Arm, Open-label, Multicenter Phase 3 Study to 
Evaluate the Safety and Tolerability of Multiple Subcutaneous 
Injections of Efgartigimod PH20 SC in Patients With Generalized 
Myasthenia Gravis 
Protocol Number: 
ARGX 113 2002 
Sponsor Signatory: 
 
 
See appended signature page 
 
 
, MD, PhD 
Chief Medical Officer 
 
Date  
 
 
 
 
System Version: 1.0, Status: Approved, Document ID: VV-TMF-88586

Clinical Study Protocol ARGX-113-2002 v3.0 
 02 Feb 2023 
Efgartigimod PH20 SC 
argenx BV 
Confidential 
Page 5 of 120 
EMERGENCY CONTACT INFORMATION 
In the event of a serious adverse event (SAE), the investigator must inform argenx within 
24 hours. A copy of the SAE form must also be sent to the contract research organization 
(CRO)/argenx BV medical monitor using the details below. 
Email: safety@argenx.com  
Toll-free Fax: +1 833 874 7325 
The following numbers are also available for urgent contact: 
 
24-Hour Urgent Medical Helpline Number: 
 
EMEA/APAC +44 1223 374 240 
 
North America +1 800 201 8725 
 
 
System Version: 1.0, Status: Approved, Document ID: VV-TMF-88586

Clinical Study Protocol ARGX-113-2002 v3.0 
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Page 6 of 120 
PROTOCOL AMENDMENT SUMMARY OF CHANGES 
Global protocol document history 
Date 
Protocol version 3.0 
02 Feb 2023 
Protocol version 2.0 
10 May 2021 
Protocol version 1.0 
14 Dec 2020 
Amendment 2 (02 Feb 2023) 
This amendment is considered to be substantial based on the criteria set forth in Article 10(a) of 
Directive 2991/20/EC of the European Parliament and the Council of the European Union. 
Overall Rationale for the Amendment 
The overall rationale for this amendment is:  
• to extend the study duration 
• to reduce the frequency of assessments from the second year onward, and to reduce 
requirements for on-site visits when the participant does not need treatment 
• to align with the established safety, efficacy, and PK/PD profile of efgartigimod, 
which will reduce the burden for the participants  
• to add optional photograph monitoring of injection site reactions 
Changes from the Germany-specific protocol v2.2 have also been included. This global protocol 
v3.0 supersedes the Germany-specific protocol v2.2. For considerations and amendment history 
specific to Germany, please refer to Section 10.8. Changes in this protocol amendment apply 
once approval is completed within the given country. 
The protocol has also incorporated the content of administrative clarification letters. The major 
changes from protocol v2.0 compared with protocol v3.0 are summarized in the following table. 
Minor editorial changes are not summarized, including correction of typographical errors and 
formatting inconsistencies. Refer to Section 10.7.2 of the protocol for any undefined 
abbreviations. 
 
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Summary of Changes Between Protocol Version 2.0 and Protocol Version 3.0 
Section and name 
Description of change 
Brief rationale 
Section 1.3 Schedule of 
Activities 
Section 8.8.2 
 
Section 10.6.3.4 Critical 
Parameters to Be Collected 
During the Study 
A new SoA has been 
created for the second 
year onward, with fewer 
assessments. The 
footnotes in the year 1 
SoA have also been 
modified to remove 
references to year 2, and 
the EoS visit has been 
removed from year 1.  
 
Reduction of efficacy and 
safety assessments and 
removal of PD, PK, and 
QoL assessments from the 
year 2 SoA (compared to 
year 1 SoA) includes: 
MG-ADL, SIB risk 
monitoring: removed 
assessment at visit 
TPnV2/3/4  
PD, PK, 
, MG-QoL15r, EQ-5D-
5L: removed all visits 
Safety laboratory tests, 
urinalysis, urine 
pregnancy test, vital 
signs, ECG, physical 
examination, 
immunogenicity: only 
retained at TPnV1, at 
every 5 visits for IP visits 
(starting with IPnV5), at 
ET/SFU and EoS visit, 
and at UNS visit when 
considered necessary by 
the investigator 
 
References to “TPnVn” 
have also been corrected to 
“TPnVm,” because “n” 
should refer to the 
treatment period number, 
and “m” should refer to the 
visit number. 
Efficacy/PD/PK: 
Consistency in efficacy, PD, and PK of 
efgartigimod is well established (refer to 
the current IB). Therefore, the clinical 
assessments can be reduced and the 
collection of PD and PK samples can be 
removed from the second year onward. 
 
Safety/immunogenicity: 
A favorable benefit-risk profile of EFG in 
gMG patients has been established. 
Frequency of safety assessments will be 
adapted to align with the safety profile of 
efgartigimod and to reduce the burden on 
the participant. Pregnancy testing is also 
reduced in frequency because reproductive 
toxicity risk has been shown to be low 
(refer to the current IB).  
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Section and name 
Description of change 
Brief rationale 
Section 4.1 Overall Design 
Section 1.1 Synopsis 
Section 1.2 Schema 
Section 1.3 Schedule of 
Activities 
 
The total study duration has 
been extended. Participants 
will remain in the study for 
at least 1 year, until 
efgartigimod PH20 SC 
becomes commercially 
available or available 
through another continued 
access program for gMG, 
or until 31 Dec 2024, 
whichever comes first. 
The study has been extended to provide 
prolonged access to IMP, to provide 
additional benefit for the participant and 
collect safety data beyond 2 years of 
exposure. 
Section 8.3.7 AEs of 
Clinical Interest  
Section 2.3.1. Risk 
Assessment 
Section 8.2.7 Assessment of 
Injection Site  
 
Section 8.3.7 has been 
added to define AEs of 
clinical interest, revise the 
definition of injection-site 
reaction (ISR), and 
include the option for 
photographic monitoring.  
 
Section 2.3.1 has been 
renamed and updated to 
align with Section 8.3.7.  
 
Former Section 8.2.7 was 
deleted because it was 
redundant to the new 
Section 8.3.7. 
The definition of ISR was revised to clarify 
that injection-site reactions and injection-
related reactions are AEs of clinical 
interest. ISR photographic monitoring is 
now included to allow collection of more 
ISR information. 
Section 2.3.1, Table 3 
Potential Risks and 
Mitigation Strategies 
Risks and mitigation 
strategies for serious 
infection, injection-related 
reactions, and injection-
site reactions have been 
updated; risks and 
mitigation strategies for 
teratogenicity/fetotoxicity 
have been deleted. 
The safety information on potential risks 
and mitigation strategies has been updated. 
Section 2 Introduction 
The introduction, 
background, and 
benefit/risk assessment 
sections were updated to 
streamline the most recent 
information regarding 
efgartigimod studies and 
risks and benefits.  
The efficacy and safety of efgartigimod has 
been established, and efgartigimod is 
approved in various regions. The 
introduction, background, and benefit/risk 
assessment sections have been updated to 
reflect this.  
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Section and name 
Description of change 
Brief rationale 
Section 6.8.3 Prohibited 
Medications and Procedures 
 
The language was updated 
on prohibited therapies 
that will result in 
participant discontinuation 
and prohibited activities 
during year 1 that will not 
require discontinuation. 
The text was updated to clarify which 
prohibited therapies must result in 
participant discontinuation from the study, 
and which prohibited activities during 
year 1 do not require discontinuation from 
the study. 
Section 7.2 Participant 
Discontinuation/Withdrawal 
From the Study 
The following bullet point 
was added: “participant 
develops a new or 
recurrent malignancy 
except for basal cell 
carcinoma of the skin, 
regardless of relationship.” 
The discontinuation requirement was 
added to ensure any participant receiving a 
malignancy diagnosis—whether recurrent 
or not—except basal cell carcinoma of the 
skin, permanently discontinues IMP. 
Section 8.2.4 
Electrocardiograms 
The ECG instructions were 
revised to indicate that 
single 12-lead ECGs will 
be obtained predose on 
dosing days, using an ECG 
machine. 
The ECG instructions have been simplified 
to align the protocol with the Data Transfer 
Agreement with the ECG vendor. 
Section 10.1.3 Informed 
Consent Process 
The language was updated 
to clarify that before 
signing the ICF, 
participants will be 
instructed not to participate 
in any other clinical study 
that involves a therapeutic 
intervention until the 
completion of the study.  
Participants should no longer be excluded or 
discontinued for enrolling in another study 
not involving a therapeutic intervention. 
This change aligns with the protocol 
clarification letter dated 24 Aug 2021. 
Section 10.6.3.3 Study 
Protocol Changes  
 
 
The home nurse and home 
visit language was 
updated: 
• Added “if allowed per 
local requirement" to the 
sentence “A home nurse 
will be a qualified 
person from either the 
study site staff or a 
home health care 
vendor.”  
• Removed “Mandatory 
site visits and home 
visits” section (formerly 
Section 10.7.3.5). 
The language was updated to account for 
local requirements, to allow the home 
nurse to be either study site staff or staff 
from a home health care vendor, and to 
note that the use of a home nurse depends 
on regional availability. 
System Version: 1.0, Status: Approved, Document ID: VV-TMF-88586

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Section and name 
Description of change 
Brief rationale 
Section 10.2 Clinical 
Laboratory Tests  
Section 1.3 Schedule of 
Activities  
 
Section 10.2.1 was 
removed, which included 
apolipoprotein B (apoB), 
lipoprotein A, fibrinogen, 
von Willebrand factor, d-
dimer, and proprotein 
convertase subtilisin/kexin 
type 9 serine protease 
(PCSK9). 
Efgartigimod does not reduce albumin 
levels and has had no observed effect on 
cholesterol, high density lipoprotein, or 
low density lipoprotein levels. Therefore, 
the monitoring of factors influenced by 
changing lipid levels is not relevant. 
 
The removal of PCSK9 aligns with the 
protocol clarification letter dated 03 Feb 
2022. 
Section 11 References 
The former Investigator's 
Brochure (IB) references 
4 and 5 were removed; 
language was changed to 
“refer to current IBs” 
throughout. 
The references were updated to remove 
outdated IBs. 
Section 10.1.9 Study and 
Site Start and Closure 
The following additional 
criteria for study 
termination were added: 
• An unexpected negative 
change to the benefit-
risk profile of the IMP 
• Recommendation of 
termination by the 
DSMB 
• A necessary adjustment 
to the maximum insured 
sum for the study that is 
not possible 
• Regulatory agency 
and/or IRB/IEC 
approvals withdrawn 
Criteria for study termination were added 
based on feedback from the ethics 
committee in Germany. These changes 
align with Germany-specific protocol v2.2. 
 
 
Section 10.6 Appendix 6: 
Administrative Structure 
Section 10.6. Appendix 6 
was removed, including 
Table 4, List of Vendor 
Information. 
Regulation (EU) No. 536/2014 does not 
require a list of the vendors in the protocol. 
Section 5.1 Inclusion 
Criteria 
Inclusion criterion 2a was 
revised to read as follows:  
“…Were discontinued 
from study treatment for 
reasons other than 
pregnancy or a life-
threatening SAE. 
Receiving rescue therapy 
The inclusion criterion was updated to 
clarify that a participant is eligible if they 
were discontinued due to an SAE that was 
not life-threatening.  
 
This revision aligns with the protocol 
clarification letter dated 01 Dec 2021. 
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Section and name 
Description of change 
Brief rationale 
is not exclusionary unless 
given in a response to a 
life-threatening situation.” 
Section 4.1 Overall Design 
Section 1.3 Schedule of 
Activities (Table 1) 
Section 10.6.3.3 Study 
Protocol Changes  
The language has been 
updated to clarify that the 
first and second visits of 
an IP, before the first TP 
and after a TP, must occur 
on-site. 
The language was updated to align with the 
protocol clarification letter dated 03 Feb 
2022. 
Section 8.2.8.2 ADA 
Against rHuPH20 
Section 1.3 Schedule of 
Activities  
 
The language was updated 
to clarify that the baseline 
sample for ADA against 
recombinant human 
hyaluronidase PH20 
(rHuPH20) will not be 
obtained until the first 
visit of the first TP 
(TP1V1), and that 
samples taken during the 
second year will only be 
analyzed if needed for 
safety purposes. 
The language was updated to align with the 
protocol clarification letter dated 03 Feb 
2022 and to clarify how samples will be 
used in the second year. 
Section 8.3.7.2 
Injection-Site Reaction 
The section was updated 
to include the most 
frequently reported 
injection-site reactions 
and to update the routine 
precautionary procedures 
regarding injection-site 
reactions. 
This text was updated to align with current 
company standards on injection-site 
monitoring. 
Section 4.1 Overall Design 
Section 1.1 Synopsis 
Section 1.3 Schedule of 
Activities  
Section 6.2.2 Handling 
Section 6.4 Study 
Intervention Compliance 
The language in Section 
4.1 was updated to specify 
that ≥2 visits are required 
for a participant or 
caregiver to be considered 
competent to administer 
efgartigimod PH20 SC at 
home. Cross-references to 
Section 4.1 have replaced 
detailed explanations in 
other sections. 
The language was updated to align with the 
protocol clarification letter dated 03 Feb 
2022. 
Section 8.2.9 Vaccine 
Antibody Titers and 
PBMCs 
 
The vaccination language 
has been updated to read 
as follows: 
The language was updated to clarify the 
time points when additional blood samples 
may be needed if the participant receives a 
vaccination during the study. 
 
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Section and name 
Description of change 
Brief rationale 
Section 1.3 Schedule of 
Activities  
“…the following samples 
are to be taken in case of 
vaccination: 
• The baseline serum 
sample can be taken at 
any moment before the 
vaccination is 
administered. This 
sample does not have to 
be taken at the baseline 
visit. 
• The second serum 
sample is to be taken at 
least 4 weeks after the 
vaccine has been 
administered. 
• A third serum sample is 
to be taken at the first 
IPnV1 that is at least 4 
weeks after the vaccine 
has been given. In case 
the visits of the second 
and the third sample 
coincide, then only 1 
sample is needed.” 
This change aligns with the protocol 
clarification letter dated 24 Aug 2021. 
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Section and name 
Description of change 
Brief rationale 
Section 10.2 Clinical 
Laboratory Tests 
Table 7 has been updated 
to include bilirubin (total 
and direct), gamma-
glutamyl transferase 
(GGT [γ-GT]), C-reactive 
protein (CRP), lactate 
dehydrogenase (LDH), 
international normalized 
ratio (INR), and activated 
partial thromboplastin 
time (aPTT). Total 
protein, mean corpuscular 
hemoglobin (MCH), and 
urobilinogen were 
removed. 
The table was further 
updated as follows: 
• 
Added prothrombin 
time (PT)  
• 
Added coagulation 
panel label, which 
includes aPTT, PT, 
and INR 
• 
Updated “routine 
analysis” label to 
“routine urinalysis” 
• 
Updated “MV” to 
“MCV” (mean 
corpuscular volume) 
• 
Added “WBC count 
with differential” as a 
heading for basophils, 
eosinophils, 
lymphocytes, 
monocytes, and 
neutrophils  
• 
Added “RBC indices” 
as a heading for MCV 
and % reticulocytes 
• 
Added creatinine 
clearance to clinical 
chemistry 
The table was updated to correct the 
unintentional removal and insertion of 
laboratory  
parameters in protocol v2.0 (10 May 
2021). This change aligns with the protocol 
clarification letter dated 18 Jul 2022, and 
with the changes made in Germany-
specific protocol v2.2. 
 
PT was added because the central lab 
analyzes PT as a part of the coagulation 
panel.  
 
Creatinine clearance was added to clarify 
that this measurement is required. 
 
Edits to the labeling were made for clarity. 
Section 4.1 Overall Design 
Section 1.1 Synopsis 
Section 1.2 Schema 
The 28-day restriction 
between treatment periods 
for year 2 onward was 
removed, and treatment 
As treatment management aims at 
minimizing fluctuations in disease severity, 
some participants may benefit from earlier 
initiation of the subsequent treatment 
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Section and name 
Description of change 
Brief rationale 
Section 1.3 Schedule of 
Activities 
Section 4.3 Justification for 
Dose 
Section 6.5 Dose 
Modification 
Section 7.1.1 Temporary 
Discontinuation of Study 
Intervention 
 
period labels were 
updated.  
The limit of 14 treatment 
periods was removed, and 
the number of weeks 
required for retreatment to 
occur was adjusted. 
All references to 
“treatment cycle” were 
changed to “treatment 
period” for clarity. Errors 
and unclear references to 
“IPnVm” labeling have 
been corrected. 
period. Changes were made to allow for 
collection of safety data in participants 
with cycles <50 days.  
 
 
Section 6.7 Treatment of 
Overdose 
The section was updated 
to define and differentiate 
overdose and medication 
error, and to describe the 
specific administration 
amounts and timeframes 
that constitute 
overdoses/medication 
errors.  
The text was updated to clarify the 
difference between overdoses and 
medication errors that are specific to SC 
administration. 
Section 6.4.2 Protocol 
Deviations 
Language was removed 
that suggested approval 
from the sponsor is 
allowed for protocol 
deviations. 
The sponsor does not approve or reject 
protocol deviations. 
Section 6.2.3 Storage 
Certificate of analysis and 
certificate of conformity 
were removed from 
required documents for 
the investigator. 
The language was updated to align with 
required documents per GCP regulatory 
requirements.  
Section 10.6.3.2 Testing for 
COVID-19 
The COVID-19 testing 
requirements were 
updated to clarify that 
participants must test 
negative for SARS-CoV-2 
and be symptom free to be 
(re)treated. 
 
The language was updated to align with 
other parts of the text. 
Section 1.1 Synopsis 
 “Overall Design” was 
updated to remove the 
requirement that 
participants be on current 
gMG therapy. 
This requirement was removed because the 
current gMG therapy may be tapered per 
investigator discretion. 
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Section and name 
Description of change 
Brief rationale 
Section 4.4 End of Study 
Definition 
The end of study 
definition was updated to: 
“The end of the study is 
defined as the date of the 
last participant’s last 
visit.” 
The text was updated to clarify that the end 
of the study is not related to whether a 
participant discontinues early. 
Section 6.6 Continued 
Access to IMP After the 
End of the Study 
The section was retitled 
and its text replaced with 
the following: 
“At the end of the study, 
argenx cannot guarantee 
continued access for 
participants but will 
comply with all local laws 
and regulations.” 
The language was updated to reflect the 
sponsor’s updated policy for continued 
access to IMP.  
Section 8.2.2 Physical 
Examinations 
The following text was 
deleted:  
“Weight will be measured 
at study entry, at the 
ET/SFU visit, at the EoS 
visit, and at UNS visits.” 
The in-text reference to time points for 
weight measurement was removed because 
all respective time points are specified in 
the SoA.  
Section 8.2.3 Vital Signs 
The first paragraph of the 
section was edited to 
remove “…be measured 
in a semi-supine position 
after 5 minutes rest and 
will…” 
This text was removed because it is 
redundant. 
Section 8.2.7 Pregnancy 
Testing 
The section was updated 
to refer to the SoA for the 
timing of urine pregnancy 
testing and to remove 
reference to serum 
pregnancy testing and 
testing entry criteria. 
The text was updated to clarify when a 
urine pregnancy test should be used and to 
clarify that there is no screening visit in 
this study and no pregnancy serum testing.  
1.1 Synopsis 
1.3 Schedule of Activities 
The language was updated 
to clarify that if a 
participant enters year 2 
of the study during a TP, 
the remaining TP visits 
and subsequent IPnV1 
must be completed 
according to the year 1 
SoA. 
The language was updated to provide 
instruction on which SoA applies if a 
participant transitions to year 2 during a 
TP. 
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Section and name 
Description of change 
Brief rationale 
10.5.2.2 Male 
Contraception 
Section 5.1 Inclusion 
Criteria 
The language has been 
updated to note that there 
is no requirement for male 
contraception.  
The requirements were updated to align 
with most the recent version of the 
efgartigimod IB. 
Section 5.2 Exclusion 
Criteria 
Criterion 3a has been 
updated to indicate that 
medical conditions are 
relative to rollover, not 
screening. 
This study does not have a screening visit, 
so medical condition requirements are 
relative to rollover.  
Section 1.2 Schema 
Figure 2 was updated to 
align the visit labels with 
Figure 1. 
Visit numbers in Figure 2 were clarified. 
Signature of the Sponsor 
The sponsor signatory has 
been updated to 
 
 MD, PhD. 
The signature page was updated to reflect 
the sponsor’s current chief medical officer. 
 
 
 
 
 
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TABLE OF CONTENTS 
SIGNATURE OF THE SPONSOR .................................................................................................3 
EMERGENCY CONTACT INFORMATION ................................................................................5 
PROTOCOL AMENDMENT SUMMARY OF CHANGES ..........................................................6 
1. 
PROTOCOL SUMMARY ..........................................................................................23 
1.1. 
Synopsis ......................................................................................................................23 
1.2. 
Schema ........................................................................................................................28 
1.3. 
Schedule of Activities .................................................................................................30 
2. 
INTRODUCTION ......................................................................................................38 
2.1. 
Study Rationale ...........................................................................................................38 
2.2. 
Background .................................................................................................................38 
2.3. 
Benefit/Risk Assessment ............................................................................................39 
2.3.1. 
Risk Assessment .........................................................................................................39 
2.3.2. 
Overall Benefit-Risk Conclusion ................................................................................40 
3. 
OBJECTIVES AND ENDPOINTS ............................................................................41 
4. 
STUDY DESIGN .......................................................................................................43 
4.1. 
Overall Design ............................................................................................................43 
4.2. 
Scientific Rationale for Study Design ........................................................................44 
4.3. 
Justification for Dose ..................................................................................................45 
4.4. 
End of Study Definition ..............................................................................................45 
5. 
STUDY POPULATION .............................................................................................46 
5.1. 
Inclusion Criteria ........................................................................................................46 
5.2. 
Exclusion Criteria .......................................................................................................47 
5.3. 
Lifestyle Considerations .............................................................................................47 
5.4. 
Screen Failures ............................................................................................................48 
5.5. 
Criteria for Temporarily Delaying Administration of Study Intervention .................48 
6. 
STUDY INTERVENTION(S) AND CONCOMITANT THERAPY ........................49 
6.1. 
Study Intervention(s) Administered ...........................................................................49 
6.2. 
Preparation/Handling/Storage/Accountability ............................................................49 
6.2.1. 
Preparation ..................................................................................................................49 
6.2.2. 
Handling .....................................................................................................................50 
6.2.3. 
Storage ........................................................................................................................50 
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6.2.4. 
Accountability .............................................................................................................50 
6.3. 
Measures to Minimize Bias: Randomization and Blinding ........................................51 
6.4. 
Study Intervention Compliance ..................................................................................51 
6.4.1. 
Handling Missed Doses of the IMP ............................................................................52 
6.4.2. 
Protocol Deviations ....................................................................................................52 
6.5. 
Dose Modification ......................................................................................................52 
6.5.1. 
Retreatment Criteria ....................................................................................................52 
6.6. 
Continued Access to IMP After the End of the Study ................................................53 
6.7. 
Treatment of Overdose ...............................................................................................53 
6.8. 
Concomitant Therapy .................................................................................................53 
6.8.1. 
Prior Medication and Procedures ................................................................................54 
6.8.2. 
Permitted Concomitant Medication and Procedures ..................................................54 
6.8.3. 
Prohibited Medications and Procedures .....................................................................55 
6.8.4. 
Rescue Therapy ..........................................................................................................55 
7. 
IMP DISCONTINUATION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL ..................................................................57 
7.1. 
IMP Discontinuation ...................................................................................................57 
7.1.1. 
Temporary Discontinuation of Study Intervention .....................................................57 
7.2. 
Participant Discontinuation/Withdrawal From the Study ...........................................57 
7.3. 
Lost to Follow-up .......................................................................................................58 
8. 
STUDY ASSESSMENTS AND PROCEDURES ......................................................60 
8.1. 
Efficacy Assessments .................................................................................................60 
8.1.1. 
MG-ADL ....................................................................................................................60 
8.1.2. 
MG-QoL15r ................................................................................................................60 
8.1.3. 
EQ-5D-5L ...................................................................................................................61 
8.1.4. 
Pharmacodynamics .....................................................................................................61 
8.2. 
Safety Assessments .....................................................................................................62 
8.2.1. 
Demography ...............................................................................................................62 
8.2.2. 
Physical Examinations ................................................................................................62 
8.2.3. 
Vital Signs ..................................................................................................................62 
8.2.4. 
Electrocardiograms .....................................................................................................62 
8.2.5. 
Medical and Surgical History .....................................................................................62 
8.2.6. 
Clinical Safety Laboratory Assessments ....................................................................62 
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8.2.6.1. 
Hematology, Clinical Chemistry, Coagulation Panel and Urinalysis.........................63 
8.2.6.2. 
SARS-CoV-2 Test ......................................................................................................63 
8.2.7. 
Pregnancy Testing ......................................................................................................63 
8.2.8. 
Immunogenicity ..........................................................................................................64 
8.2.8.1. 
ADA Against Efgartigimod ........................................................................................64 
8.2.8.2. 
ADA Against rHuPH20 ..............................................................................................64 
8.2.9. 
Vaccine Antibody Titers and PBMCs ........................................................................65 
8.2.10. 
Suicidal Ideation and Behavior Risk Monitoring .......................................................65 
8.3. 
Adverse Events, Serious Adverse Events, and Other Safety Reporting .....................65 
8.3.1. 
Time Period and Frequency for Collecting AE and SAE Information .......................66 
8.3.2. 
Method of Detecting AEs and SAEs ..........................................................................66 
8.3.3. 
Follow-up of AEs and SAEs .......................................................................................66 
8.3.4. 
Regulatory Reporting Requirements for SAEs ...........................................................67 
8.3.5. 
Pregnancy ...................................................................................................................67 
8.3.6. 
Adverse Events of Special Interest .............................................................................68 
8.3.7. 
AEs of Clinical Interest ..............................................................................................68 
8.3.7.1. 
Injection-Related Reactions ........................................................................................68 
8.3.7.2. 
Injection-Site Reaction ...............................................................................................68 
8.4. 
Pharmacokinetics ........................................................................................................69 
8.5. 
Genetics and/or Pharmacogenomics ...........................................................................69 
8.6. 
Biomarkers ..................................................................................................................69 
8.7. 
Immunogenicity Assessments ....................................................................................69 
8.8. 
Medical Resource Utilization and Health Economics ................................................69 
8.8.1. 
69 
8.8.2. 
70 
8.9. 
Storage of Blood Samples After the Study .................................................................70 
9. 
STATISTICAL CONSIDERATIONS .......................................................................71 
9.1. 
Statistical Hypotheses .................................................................................................71 
9.2. 
Sample Size Determination ........................................................................................71 
9.3. 
Analysis Sets ...............................................................................................................71 
9.4. 
Statistical Analyses .....................................................................................................71 
9.4.1. 
General Considerations ...............................................................................................72 
9.4.2. 
Primary Endpoint(s) ....................................................................................................72 
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9.4.3. 
Secondary Endpoint(s) ................................................................................................72 
9.4.4. 
Exploratory Endpoints ................................................................................................72 
9.5. 
Interim Analysis ..........................................................................................................72 
10. 
SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS ..................................................................................................73 
10.1. 
Appendix 1: Regulatory, Ethical, and Study Oversight Considerations ....................73 
10.1.1. 
Regulatory and Ethical Considerations ......................................................................73 
10.1.2. 
Financial Disclosure ...................................................................................................73 
10.1.3. 
Informed Consent Process ..........................................................................................74 
10.1.4. 
Data Protection ...........................................................................................................75 
10.1.5. 
Committees Structure .................................................................................................75 
10.1.5.1. 
Data Safety Monitoring Board ....................................................................................75 
10.1.6. 
Dissemination of Clinical Study Data ........................................................................75 
10.1.7. 
Data Quality Assurance ..............................................................................................76 
10.1.7.1. 
Data Handling and Record Keeping ...........................................................................76 
10.1.7.2. 
Quality Assurance Audit .............................................................................................77 
10.1.7.3. 
Quality Control ...........................................................................................................77 
10.1.8. 
Source Documents ......................................................................................................78 
10.1.9. 
Study and Site Start and Closure ................................................................................78 
10.1.10. 
Publication Policy .......................................................................................................79 
10.2. 
Appendix 2: Clinical Laboratory Tests .......................................................................80 
10.3. 
Appendix 3: Total Blood Volume Collected From Each Participant .........................81 
10.4. 
Appendix 4: AEs and SAEs: Definitions and Procedures for Recording, 
Evaluating, Follow-up, and Reporting ........................................................................82 
10.4.1. 
Definition of AE .........................................................................................................82 
10.4.2. 
Definition of SAE .......................................................................................................83 
10.4.3. 
Recording and Follow-up of AE and/or SAE .............................................................83 
10.4.4. 
Reporting of SAEs ......................................................................................................85 
10.5. 
Appendix 5: Contraceptive and Barrier Guidance ......................................................86 
10.5.1. 
Definitions ..................................................................................................................86 
10.5.2. 
Contraception Guidance .............................................................................................86 
10.5.2.1. 
Female Contraception for Women of Childbearing Potential ....................................86 
10.5.2.2. 
Male Contraception ....................................................................................................87 
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10.6. 
Appendix 6: Possible Adaptations to Study Protocol During COVID-19 
Pandemic .....................................................................................................................88 
10.6.1. 
COVID-19 Risk Assessment for Participant Safety ...................................................88 
10.6.2. 
COVID-19 Risk Mitigation ........................................................................................88 
10.6.3. 
Possible Changes in Study Design Due to the COVID-19 Pandemic ........................89 
10.6.3.1. 
Implementation of This Appendix ..............................................................................89 
10.6.3.2. 
Testing for COVID-19 ................................................................................................89 
10.6.3.3. 
Study Protocol Changes ..............................................................................................89 
10.6.3.4. 
Critical Parameters to Be Collected During the Study ...............................................90 
10.7. 
Appendix 7: Abbreviations and Definitions ...............................................................91 
10.7.1. 
Definitions ..................................................................................................................91 
10.7.2. 
Abbreviations ..............................................................................................................91 
10.8. 
Appendix 8: Germany-Specific Requirements ...........................................................93 
10.8.1. 
Overview .....................................................................................................................93 
10.8.2. 
Germany-Specific Document History ........................................................................94 
10.8.3. 
Summary of Changes Between Protocol Version 2.1-GER and Protocol 
Version 2.2-GER ........................................................................................................94 
10.8.4. 
Summary of Changes Between Protocol Version 1.5-GER and Protocol 
Version 2.1-GER ........................................................................................................97 
10.8.5. 
Summary of Changes Between Protocol Version 1.0 and Protocol Version 
1.5-GER ....................................................................................................................106 
10.9. 
Appendix 9: Summary of Changes Between Protocol Version 1.0 and 
Protocol Version 2.0 .................................................................................................110 
11. 
REFERENCES .........................................................................................................120 
 
LIST OF TABLES 
Table 1: 
Schedule of Activities for Year 1 ...............................................................................30 
Table 2: 
Schedule of Activities for Year 2 Onward .................................................................35 
Table 3: 
Potential Risks and Mitigation Strategies ...................................................................40 
Table 4: 
Study ARGX-113-2002 Objectives and Endpoints ....................................................41 
Table 5: 
Study Intervention Administered ................................................................................49 
Table 6: 
Analysis Sets ...............................................................................................................71 
Table 7: 
Protocol-Required Safety Laboratory Tests ...............................................................80 
 
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LIST OF FIGURES 
Figure 1: 
Schema for Participants in Need of Retreatment at Study Entry ................................28 
Figure 2: 
Schema for Participants Not in Need of Retreatment at Study Entry .........................29 
 
 
 
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1. 
PROTOCOL SUMMARY 
1.1. 
Synopsis 
Protocol Title: 
A Long-term, Single-Arm, Open-label, Multicenter Phase 3 Study to Evaluate the Safety and 
Tolerability of Multiple Subcutaneous Injections of Efgartigimod PH20 SC in Patients With 
Generalized Myasthenia Gravis  
Brief Title: Evaluating the Long-term Safety and Tolerability of Efgartigimod PH20 SC 
Administered Subcutaneously in Patients With Generalized Myasthenia Gravis 
Rationale: 
The aim is to evaluate the long-term safety and tolerability of efgartigimod coformulated with 
recombinant human hyaluronidase PH20 (rHuPH20) administered subcutaneously (SC) 
(efgartigimod PH20 SC) and its efficacy in patients with generalized myasthenia gravis (gMG). 
Objectives and Endpoints: 
Objectives 
Endpoints 
Primary 
 
• To evaluate the long-term safety and 
tolerability of efgartigimod PH20 SC in 
participants with gMG 
• Incidence and severity of adverse events 
(AEs), incidence of serious adverse 
events (SAEs) and AEs of special interest 
(AESIs) and changes in laboratory test 
results, physical examination results, 
vital signs, and electrocardiogram results 
Secondary 
 
• To evaluate the impact of efgartigimod 
PH20 SC on disease severity 
• Myasthenia Gravis Activities of Daily 
Living (MG-ADL) total score changes 
from baseline and cycle baseline over 
time by cycle 
• To evaluate the effect of efgartigimod 
PH20 SC on pharmacodynamics (PD) 
• Percentage reduction in levels of total 
immunoglobulin G (IgG) from baseline 
and cycle baseline over time by cycle 
• Percentage reduction of 
anti-acetylcholine receptor antibodies 
(AChR-Ab) from baseline and cycle 
baseline over time by cycle in AChR-Ab 
seropositive participants 
• To evaluate the PK of efgartigimod PH20 
SC 
• Efgartigimod serum concentrations 
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• To evaluate the immunogenicity of 
efgartigimod PH20 SC 
• Incidence and prevalence of anti-drug 
antibodies (ADAs) to efgartigimod over 
time  
• Incidence and prevalence of neutralizing 
antibodies (NAbs) against efgartigimod 
over time 
• Incidence and prevalence of ADAs to 
rHuPH20 over time  
• Incidence and prevalence of NAbs 
against rHuPH20 over time 
• To evaluate the impact of efgartigimod 
PH20 SC on the quality of life (QoL) of 
the participants 
• Changes in total Myasthenia Gravis 
Quality of Life Questionnaire (15-item 
scale revised) (MG-QoL15r) from 
baseline and cycle baseline by cycle 
• Changes in EuroQoL 5-Dimensions 
5-Level (EQ-5D-5L) visual analog scale 
(VAS) score from baseline and cycle 
baseline over time by cycle 
• EQ-5D-5L responses to 5 dimensions (ie, 
mobility, self-care, usual activities, 
pain/discomfort, anxiety/depression) over 
time by cycle 
• To evaluate feasibility of 
self-administration of efgartigimod 
PH20 SC 
• Number and percentage of participants 
who performed self-administration at 
home over time by cycle 
• Number and percentage of caregivers 
who administered the injection to the 
participant at home over time by cycle 
• Number of training visits needed for the 
participant or caregiver to be competent 
to start administering efgartigimod 
PH20 SC 
• Number and percentage of self- or 
caregiver-supported study drug 
administration among all study treatment 
visits at home 
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Exploratory 
 
• 
 
 
 
• 
 
 
 
 
 
 
• 
 
 
Overall Design: 
ARGX-113-2002 is an open-label, multicenter, long-term safety study in patients with gMG, 
including both anti-acetylcholine receptor antibody (AChR-Ab) seropositive and seronegative 
participants. Participants will enter the study from either study ARGX-113-2001 or from study 
ARGX-113-1705. Once a participant has clinical need of retreatment, they will receive 
efgartigimod PH20 SC 1000 mg every 7 days (q7d) for a total of 4 injections in a treatment 
period (TP). Depending on the clinical effect, participants may be retreated as needed using a 
variable number of TPs. An independent Data and Safety Monitoring Board (DSMB) will 
periodically review and evaluate the accumulated study data for participant safety, study 
conduct, and study progress. The DSMB will make recommendations to the sponsor concerning 
the continuation, modification or termination of the study. 
Brief Summary: 
The purpose of this study is to evaluate the long-term safety and tolerability of efgartigimod 
PH20 SC 1000 mg, and the clinical efficacy, PD, pharmacokinetics (PK), immunogenicity, 
impact on the QoL of the participants, treatment satisfaction, and administration method 
preference, and the feasibility of self- and caregiver-supported administration of the SC injection. 
PD and PK will only be measured and assessed through the first year. 
 
Study details include: 
• Study duration and treatment duration: from the participant’s first visit in this study until, at 
the latest, 31 Dec 2024 
• Treatment period and intertreatment period (IP):  
− Year 1: 3-week TPs of once weekly injections, repeated as needed with at least 28 
days between TPs 
− Year 2 onward: 3-week TPs of once weekly injections. It is recommended to have 
IPs of at least 28 days, but a subsequent treatment period can be administered 
earlier based on clinical evaluation at the discretion of the investigator. A minimal 
interval of 7 days after the last investigational medicinal product (IMP) 
administration of the previous cycle must be maintained.  
• Study Assessments and Procedures:  
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− Year 1: total levels of immunoglobulin G (IgG), AChR-Ab levels, MG-ADL 
− Year 2: MG-ADL 
• Visit frequency:  
− Year 1: every week during the TPs. Then, the first IP visit is 1 week after the last 
TP visit, then every 21 days (+7 days) until the participant is in need of 
retreatment 
− Year 2 onward: every week during the TPs. Then, the first IP visit, if applicable, 
is 1 week after the last TP visit, and then every 21 days (+7 days). The new TP 
can start as soon as 1 week after the last TP, depending on when the participant is 
in need of retreatment. 
Number of Participants: 
Up to 201 participants may be enrolled from the antecedent studies ARGX-113-2001 and 
ARGX-113-1705. See Section 9.2. 
Note: “Enrolled” means a participant’s agreement to enter a clinical study following completion 
of the informed consent process and screening. Potential participants who are screened for the 
purpose of determining eligibility for the study, but do not participate in the study, are not 
considered enrolled unless otherwise specified by the protocol. 
Intervention Groups and Duration: 
The study spans the following study periods: 
• treatment period (TP):  
− All years: 3 weeks, repeated as needed based on clinical evaluation by the 
investigator 
− If a participant enters year 2 of the study during a TP, the remaining TP visits and 
subsequent IPnV1 must be completed according to the Year 1 SoA (refer to 
Table 1).  
• intertreatment period (IP):  
− Year 1: at least 28 days between TPs 
− Year 2 onward: recommended to have IPs of at least 28 days, but a subsequent TP 
can be administered earlier based on clinical evaluation at the discretion of the 
investigator. A minimal interval of 7 days after the last IMP administration of 
previous cycle must be maintained.  
 
Eligible participants will enter the study on their last visit of the antecedent study, 
ARGX-113-2001 or ARGX-113-1705. If they are in need of retreatment, the participants will 
start with a TP. A TP will consist of an injection of efgartigimod PH20 SC 1000 mg q7d for a 
total of 4 injections. If the participants are not in need of retreatment, they will start with an IP 
(visit IP0V1). Participants or their caregivers will be trained to perform the injection and will be 
allowed to perform the injection when they are competent to do so. Caregiver-supported or 
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self-administration can be performed at the site or at home, based on the participant's preference. 
Participants will be discontinued from the study if it is in their best interest, as determined by the 
investigator or sponsor.  
Participants will remain in the study for at least 1 year, until efgartigimod PH20 SC becomes 
commercially available, available through another continued access program for gMG, or until 
31 Dec 2024, whichever comes first. 
Data Monitoring/Other Committee: Yes (see Section 10.1.5.1) 
 
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1.2. 
Schema 
Figure 1: 
Schema for Participants in Need of Retreatment at Study Entry  
Concomitant gMG treatmentd
TP1V1
EoP
EoSc
IP1V1
IP1Vm
TPnV1
IPnV1
IPnV2
Treatment Perioda
Weekly visits
Intertreatment Periodb
Monthly visits
Treatment Perioda
Weekly visits
Intertreatment Periodb
Monthly visits
IPnVm
 
EoP=end of study/early discontinuation visit for antecedent studies ARGX-113-2001 or ARGX-113-1705; EoS=end of study; gMG=generalized myasthenia 
gravis; IMP=investigational medicinal product; IPnVm=intertreatment period (period number) visit (visit number); PH20=recombinant human hyaluronidase 
PH20 (rHuPH20); q7d=every 7 days; SC=subcutaneous(ly); SoA=schedule of activities; TP=treatment period; TPnVm=treatment period (period number) visit 
(visit number) 
a Participants will receive efgartigimod PH20 SC 1000 mg q7d for a total of 4 injections in a TP. A new TP can be started if the participant is in need of 
retreatment as determined by the investigator, however during the first year, at least 28 days must have elapsed since the last dose of efgartigimod. During the 
second year onward, it is recommended to have at least 28 days between TPs. However, a subsequent treatment period can be administered earlier based on 
clinical evaluation at the discretion of the investigator, with a minimum interval of 7 days after the last IMP administration. In case of retreatment, there must 
be at least 4 weeks left in the study for the participant, so that a full TP and the EoS visit can be performed.  
b For the visit schedule, see the SoA (Section 1.3). 
c Participants will remain in the study for at least 1 year, until efgartigimod PH20 SC becomes commercially available or available through another continued 
access program for gMG, or until 31 Dec 2024, whichever comes first. 
d Dose reduction or changes to the dose are allowed as described in Section 6.8.2. Concomitant gMG treatment can be tapered completely. 
 
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Figure 2: 
Schema for Participants Not in Need of Retreatment at Study Entry  
Concomitant gMG treatmente
IP0V1
EoP
EoSd
IPnV1
Treatment Periodb
Weekly visits
Intertreatment Perioda
Monthly visits
IP0Vm
TP1V1
IP1Vm
Intertreatment Periodc
Monthly visits
Intertreatment Periodc
Monthly visits
Treatment Periodb
Weekly visits
IP1V1
IPnVm
TPnV1
IPnV2
 
EoP=end of study/early discontinuation visit for antecedent studies ARGX-113-2001 or ARGX-113-1705; EoS=end of study; gMG=generalized myasthenia 
gravis; IMP=investigational medicinal product; IPnVm=intertreatment period (period number) visit (visit number); PH20=recombinant human hyaluronidase 
PH20 (rHuPH20); q7d=every 7 days; SoA=schedule of activities; TP=treatment period; TPnVm=treatment period (period number) visit (visit number) 
a During the intertreatment period, visits will occur every 21 days. TP1V1 will occur when a participant is eligible for retreatment. 
b Participants will receive efgartigimod PH20 SC 1000 mg q7d for a total of 4 injections in a TP. A new TP can be started if the participant is in need of 
retreatment as determined by the investigator, however during the first year, at least 28 days must have elapsed since the last dose of efgartigimod. During the 
second year onward, it is recommended to have at least 28 days between TPs. However, a subsequent treatment period can be administered earlier based on 
clinical evaluation at the discretion of the investigator, with a minimum interval of 7 days after the last IMP administration. In case of retreatment, there must 
be at least 4 weeks left in the study for the participant, so that a full TP and the EoS visit can be performed. 
c For the visit schedule, see the SoA (Section 1.3).  
d Participants will remain in the study for at least 1 year, until efgartigimod PH20 SC becomes commercially available or available through another continued 
access program for gMG, or until 31 Dec 2024, whichever comes first. 
e Dose reduction or changes to the dose are allowed as described in Section 6.8.2. Concomitant gMG treatment can be tapered completely.
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1.3. 
Schedule of Activities 
Table 1: 
Schedule of Activities for Year 1 
Visit Type 
Treatment Period 
Intertreatment 
Period 
 
 
TPnV1a,b 
PK1b,c 
TPnV2 
TPnV3 
TPnV4 
PK2b,c 
IPnV1b 
IP0V1a,b/ 
IPnVmd 
ET/SFUb,e 
UNSf 
Study Day (Visit 
Window) 
A 
A+2 
(±1) 
A+7 
(±2) 
A+14 
(±2) 
A+21 
(±2) 
A+23 
(±1) 
A+28 
(±2) 
Y+21 (+7) 
NA 
NA 
Informed consent 
Xg 
 
 
 
 
 
 
Xg 
 
 
Inclusion/ 
exclusion criteria 
Xg 
 
 
 
 
 
 
Xg 
 
 
Demographic 
characteristics 
Xg 
 
 
 
 
 
 
Xg 
 
 
Weight 
Xg 
 
 
 
 
 
 
Xg 
X 
X 
MG-ADLh 
X 
 
Xi 
Xi 
Xi 
 
X 
Xi 
X 
X 
MG-QoL15r 
X 
 
Xi 
Xi 
Xi 
 
X 
Xi 
X 
X 
EQ-5D-5L 
X 
 
 
 
 
 
X 
Xi 
X 
X 
 
 
SIB risk 
monitoringm 
X 
 
Xi 
Xi 
Xi 
 
X 
Xi 
X 
X 
Single 12-lead 
ECG 
X 
 
 
 
 
 
X 
X 
X 
X 
Physical 
examination 
X 
 
 
 
 
 
X 
X 
X 
X 
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Visit Type 
Treatment Period 
Intertreatment 
Period 
 
 
TPnV1a,b 
PK1b,c 
TPnV2 
TPnV3 
TPnV4 
PK2b,c 
IPnV1b 
IP0V1a,b/ 
IPnVmd 
ET/SFUb,e 
UNSf 
Study Day (Visit 
Window) 
A 
A+2 
(±1) 
A+7 
(±2) 
A+14 
(±2) 
A+21 
(±2) 
A+23 
(±1) 
A+28 
(±2) 
Y+21 (+7) 
NA 
NA 
Vital signs 
X 
 
 
 
 
 
X 
X 
X 
X 
Safety laboratory 
testsn 
X 
 
 
 
 
 
X 
X 
X 
X 
Vaccination 
antibody titers and 
PBMCso 
(X) 
 
(X) 
(X) 
(X) 
 
(X) 
(X) 
(X) 
X 
Immunogenicityp 
X 
 
 
 
 
 
X 
X 
X 
X 
Pharmaco-
dynamicsq 
X 
 
 
 
 
 
X 
X 
X 
X 
Pharmacokinetics  
Xr 
X 
 
 
 
X 
X 
 
X 
X 
SARS-CoV-2 tests 
 
 
 
 
 
 
 
 
 
X 
Urinalysis 
X 
 
 
 
 
 
X 
X 
X 
X 
Urine pregnancy 
testt 
X 
 
 
 
 
 
X 
X 
X 
X 
Efgartigimod 
PH20 SC 
administration 
trainingu 
X 
 
(X) 
(X) 
(X) 
 
X 
(X) 
 
X 
Efgartigimod 
PH20 SC 
administrationv 
X 
 
Xi 
Xi 
Xi 
 
 
 
 
 
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Visit Type 
Treatment Period 
Intertreatment 
Period 
 
 
TPnV1a,b 
PK1b,c 
TPnV2 
TPnV3 
TPnV4 
PK2b,c 
IPnV1b 
IP0V1a,b/ 
IPnVmd 
ET/SFUb,e 
UNSf 
Study Day (Visit 
Window) 
A 
A+2 
(±1) 
A+7 
(±2) 
A+14 
(±2) 
A+21 
(±2) 
A+23 
(±1) 
A+28 
(±2) 
Y+21 (+7) 
NA 
NA 
Administration 
compliance 
monitoringw 
Continuous monitoringi 
Assessment of 
injection sitex 
Continuous monitoringi 
Hospitalization 
monitoringy 
Continuous monitoringi 
Adverse eventsy 
Continuous monitoringi 
Prior/concomitant 
therapy and 
proceduresy 
Continuous monitoringi 
A=day 1 of a TP; AChR-Ab=anti-acetylcholine receptor antibody; ADA=antidrug antibodies; AE=adverse event; eCRF=electronic case report form; 
ECG=electrocardiogram; ET=end of treatment; FSH=follicle-stimulating hormone; ICF=informed consent form; IgG =immunoglobulin G; IMP=investigational 
medicinal product; IP=intertreatment period; IPnVm=IP (period number) visit (visit number); 
; 
MG-ADL=Myasthenia Gravis Activities of Daily Living; MG-QoL15r=Myasthenia Gravis Quality of Life 15 item scale revised; NA=not applicable; 
NAb=neutralizing antibody; PBMC=peripheral blood mononuclear cell; PD=pharmacodynamics; PH20=recombinant human hyaluronidase PH20 (rHuPH20); 
PHQ-9=9-item Patient Health Questionnaire; PK=pharmacokinetics; PK1 and PK2=additional pharmacokinetic sample visits for subset of participants; 
SC=subcutaneous(ly); SFU=safety follow-up; SIB=Suicidal Ideation and Behavior; SoA=schedule of activities; TP=treatment period; TPnVm=TP (period 
number) visit (visit number); 
; UNS=unscheduled; (X)=optional activity, only done under 
specified conditions; Y=previous IP visit 
Note: All activities will be performed predose on dosing days, unless otherwise indicated. 
a The transition from the antecedent studies ARGX-113-1705 or ARGX-113-2001, to study ARGX-113-2002, can either be IP0V1 or TP1V1, depending on the 
need for retreatment. The first visit of study ARGX-113-2002 will always coincide with the last visit from studies ARGX-113-2001 or ARGX-113-1705. 
Overlapping activities performed for the last visit of these antecedent studies will not be repeated for the first visit of ARGX-113-2002. 
b This visit must always be performed at the site. All other visits can be performed by phone if IMP administration occurs at home. 
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c These are optional visits to collect additional PK samples from consenting participants. These additional visits can only be performed when all of the injections 
of that treatment period are given at the site. Sampling will only be performed during a participant’s first and/or second treatment periods that start during the 
first year.  
d These IP visits will occur every 21 days. The visit denominator (“m”) will start at 2 for each IP after a TP. At each of these IP visits performed on-site, an 
evaluation of the need for retreatment will be done prior to performing any activities so that only activities listed for IPnVm or TPnV1 are performed, 
respectively. The first visit of an IP after a TP, called IPnV1, must occur on-site. The second IP visit (IPnV2) will also be on-site. Subsequent visits may 
alternate between telephone and on-site visits. During an IP, consecutive telephone visits are not allowed, except in exceptional circumstances caused by the 
COVID-19 pandemic and after approval by the sponsor and/or the CRO. 
e For participants who discontinue early from the study, the activities will depend on the visit at which the participant had to discontinue. Participants who 
discontinue early from the study at either a TP visit or an IP visit should perform planned activities for the ET visit if 49 (±2 days) days has not elapsed since 
the last dose of efgartigimod. These participants will not receive any further administration of efgartigimod PH20 SC during the study and will return for the 
SFU visit 49 ±2 days after the last dose administration. If 49 ±2 days has already elapsed since the last administration of efgartigimod PH20 SC, then this visit 
becomes the SFU visit and the SFU visit activities must be performed. Participants who discontinue early from the study between visits should perform the 
SFU visit at least 49 ±2 days after the last dose administration. If 49 ±2 days has already elapsed since the last administration of efgartigimod, then the SFU 
visit will be planned as soon as possible. 
f A UNS visit can occur at the request of the participant or the investigator. During the UNS visit, activities indicated in the SoA can be performed at the 
discretion of the investigator, depending on the reason for the UNS visit. 
g These activities are only performed at study entry. 
h It is recommended to perform the MG-ADL scale prior to all other activities. 
i When a visit is performed by phone, only these activities must be performed. 
j 
 
k 
 
l 
 
.  
m The SIB Risk Monitoring assessment is based on question 9 of the PHQ-9. 
n Blood samples for clinical laboratory (hematology/clinical chemistry/coagulation panel and FSH, if applicable) safety assessments will be collected. See 
Section 10.2. Participants will need to be fasted for each on-site visit at which safety laboratory assessments are collected. Fasted is defined as no food or drink 
at least 8 hours prior to each sampling. Permitted medications that the participant normally takes can be taken as usual before a visit. 
o Additional blood samples (serum/PBMC) may need to be taken for additional/optional/future/vaccination research if the participant consents. If a participant 
who consents to this additional sampling receives a vaccination during the study, samples referred to in Section 8.2.9 should be taken. The closest visit that is at 
least 4 weeks after the vaccine was administered may be used. If this visit does not coincide with IPnV1, then another sample will also be taken at this visit. 
Serum samples only need to be taken when a vaccination is planned or after a vaccination has occurred. In addition, a whole-blood sample to isolate PBMCs 
will be collected at study entry and then approximately every 3 months throughout the study during a scheduled on-site visit, regardless of the vaccines a 
participant has received. 
p Titers of ADA and the presence of NAbs against efgartigimod will be measured in serum. Blood samples for plasma titer levels of ADA and NAbs against 
rHuPH20 will also be taken. A titer for ADA and the presence of NAbs against PH20 must be measured at the first visit of the first TP (TP1V1) for participants 
coming from study ARGX-113-1705 and for participants coming from study ARGX-113-2001 who received efgartigimod IV. If no sample is taken, the reason 
will be recorded. The baseline sample for ADA against rHuPH20 will not be obtained until TP1V1. 
q The PD assessments comprises levels of total IgG, and autoantibody levels (AChR-Ab levels for AChR-Ab positive participants).  
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r The PK assessments will only be taken at TP1V1.  
s A nasopharyngeal swab will be performed to sample nasal and throat mucosal cells. Participants should only be tested for SARS-CoV-2 if they have symptoms 
of COVID-19 or if they were in contact with a person who tested positive for SARS-CoV-2, unless local or site regulations have more stringent testing 
requirements. Participants may be retested as needed. See Section 10.6. 
t Only for women of childbearing potential. See Section 8.2.7 and Section 10.5.1. 
u Participants who have not previously self-administered efgartigimod PH20 SC in study ARGX-113-2001 will be instructed on self-administration as of TP1V1 
or IP0V1 in study ARGX-113-2002. Training can continue until the participant or caregiver is ready to administer efgartigimod PH20 SC to the satisfaction of 
the site staff (a minimum of 1 visit). The participant or caregiver will then perform an administration under the supervision of site staff. Therefore, a minimum 
of 2 visits is required for a participant or caregiver to be considered competent to administer efgartigimod PH20 SC at home. Caregivers must sign the ICF 
before being trained in IMP administration. (X) indicates that this activity is optional and can only be performed on-site. At every on-site visit, the study staff 
must review the administration log and patient diary with the participant. 
v The first dose administration of all TPs must be performed on-site, even if the dose is self-administered. Subsequent administrations in any TP may be 
performed at home, if the participant or caregiver has been trained and is competent to perform IMP administration. Participants or caregivers who were 
competent to administer efgartigimod PH20 SC in study ARGX-113-2001 may continue administration during study ARGX-113-2002 and may perform all but 
the first administration of a TP at home. For participants who have not previously received efgartigimod PH20 SC, self-administration or caregiver-supported 
self-administration can begin during the first TP if the participant or caregiver is trained and capable, but all these administrations must still be performed on-
site under supervision by the site staff. During subsequent TPs, administration for visits 2, 3, and 4 may be performed at home. When IMP administration is 
performed at home, the associated visit will be performed by phone. 
w When administration is performed at home, participant compliance with the efgartigimod PH20 SC dosing and administration schedule will be assessed by 
direct questioning at each visit. Any deviations from the planned dosage must be recorded. See Section 6.4. 
x When a participant is not on-site, they must record any observed injection site reaction in the patient diary. The investigator will evaluate all reported injection 
site reactions and decide whether the site reaction is classified and reported as an AE. 
y Adverse events (including ongoing AEs from the antecedent studies), use of concomitant therapies, use of rescue therapy, medical procedures performed on the 
participants, and hospitalizations will be collected from ICF signature until the last study-related activity. All available vaccination history for participants 
rolling over from ARGX-113-1705 should be recorded in the eCRF. All vaccines received during the study should be recorded as concomitant medication. See 
Section 6.8 and Section 8.3. 
 
 
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Table 2: 
Schedule of Activities for Year 2 Onward 
Visit Type 
Treatment Period 
Intertreatment Perioda 
 
 
 
 
TPnV1b,c 
TPnV2/V3/V4 
IPnV1 
IPnVmb,c 
ET/EoS/SFUb,c,d 
UNSe 
Study Day 
(Visit Window) 
A 
A+7/14/21 
(±2) 
A+28 (±2) 
Y+21 (+7) 
NA 
NA 
MG-ADLf 
X  
 
X  
X 
X  
X  
SIB risk monitoringg 
X  
   
X  
 X 
X  
X  
Single 12-lead ECG  
X  
   
  
Xh 
X  
X  
Vital signs  
X  
   
  
Xh 
X  
X  
Physical examination 
X  
 
 
Xh 
X 
X 
Weight 
 
 
 
 
X 
X 
Safety laboratory testsi 
X 
   
  
Xh  
X  
X  
Vaccination antibody titers and PBMCsj 
(X)  
(X)  
(X)  
(X) 
(X)  
X  
Immunogenicityk 
X  
   
  
Xh 
X  
X  
SARS-CoV-2 testl 
  
  
  
 
  
X 
Urinalysis  
X  
  
Xh 
X  
X  
Urine pregnancy testm 
X  
  
Xh 
X  
X  
Efgartigimod PH20 SC administration trainingn 
(X) 
(X)  
(X)  
(X)  
 (X)  
X  
Efgartigimod PH20 SC administrationo 
X  
X 
  
  
  
  
Administration compliance monitoringp 
Continuous monitoring 
Assessment of injection siteq 
Continuous monitoring 
Hospitalization monitoringr 
Continuous monitoring 
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Visit Type 
Treatment Period 
Intertreatment Perioda 
 
 
 
 
TPnV1b,c 
TPnV2/V3/V4 
IPnV1 
IPnVmb,c 
ET/EoS/SFUb,c,d 
UNSe 
Study Day 
(Visit Window) 
A 
A+7/14/21 
(±2) 
A+28 (±2) 
Y+21 (+7) 
NA 
NA 
Adverse eventsr 
Continuous monitoring 
Prior/concomitant therapy and proceduresr 
Continuous monitoring 
A=day 1 of a TP; ADA=antidrug antibodies; AE=adverse event; eCRF=electronic case report form; ECG=electrocardiogram; EoS=end of study; ET=end of 
treatment; FSH=follicle-stimulating hormone; gMG=generalized myasthenia gravis; ICF=informed consent form; IMP=investigational medicinal product; 
IP=intertreatment period; IPnVm=IP (period number) visit (visit number); MG-ADL=Myasthenia Gravis Activities of Daily Living; NA=not applicable; 
NAb=neutralizing antibody; PBMC=peripheral blood mononuclear cell; PH20=recombinant human hyaluronidase PH20 (rHuPH20); PHQ-9=9-item Patient 
Health Questionnaire; SC=subcutaneous(ly); SFU=safety follow-up; SIB=Suicidal Ideation and Behavior; SoA=schedule of activities; TP=treatment period; 
TPnVm=TP (period number) visit (visit number); UNS=unscheduled; (X)=optional activity, only done under specified conditions; Y=previous IP period visit 
Note: All activities will be performed predose on dosing days, unless otherwise indicated. If a participant enters year 2 of the study during a TP, the remaining 
TP visits and subsequent IPnV1 must be completed according to the year 1 SoA (refer to Table 1). 
a IPnV1 can become a TPn+1V1 if there are at least 7 days past the last IMP administration in the previous TP, and the participant is in need of retreatment. All 
IPnVm visits may also become a new TP, if the investigator determines there is a need for retreatment. The need for retreatment will be assessed prior to 
performing any activities, so that only activities listed for IPnV1/m or TPn+1V1 are performed, respectively. The visit denominator (“m”) will start at 2 for 
each IP after a TP. 
b Participants will remain in the study for at least 1 year, until efgartigimod PH20 SC becomes commercially available or available through another continued 
access program for gMG, or until 31 Dec 2024, whichever comes first.  
c On-site visits are required for TPnV1, for IPnV5/10/15, etc, (ie, every 5 visits), and for ET, EoS, and SFU visits. All other visits in Table 2 can be performed by 
phone, including TPnV2/3/4 in case of IMP home administration. 
d For participants who discontinue early from the study, the activities will depend on the visit at which the participant had to discontinue. Participants who 
discontinue early from the study at either a TP visit or an IP visit should perform planned activities for the ET visit if 49 (±2 days) days has not elapsed since 
the last dose of efgartigimod. These participants will not receive any further administration of efgartigimod PH20 SC during the study and will return for the 
SFU visit 49 ±2 days after the last dose administration. If 49 ±2 days has already elapsed since the last administration of efgartigimod PH20 SC, then this visit 
becomes the SFU visit and the SFU visit activities must be performed. Participants who discontinue early from the study between visits should perform the 
SFU visit at least 49 ±2 days after the last dose administration. If 49 ±2 days has already elapsed since the last administration of efgartigimod, then the SFU 
visit will be planned as soon as possible. 
e A UNS visit can occur at the request of the participant or the investigator. During the UNS visit, activities indicated in the SoA can be performed at the 
discretion of the investigator, depending on the reason for the UNS visit. 
 
f It is recommended to perform the MG-ADL scale prior to all other activities. 
g The SIB Risk Monitoring assessment is based on question 9 of the PHQ-9. 
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h These assessments will only be performed every 5 visits (IPnV5, IPnV10, etc). 
i Blood samples for clinical laboratory (hematology/clinical chemistry/coagulation panel and FSH, if applicable) safety assessments will be collected. See 
Section 10.2. Participants will need to be fasted for each on-site visit at which safety laboratory assessments are collected. Fasted is defined as no food or drink 
at least 8 hours prior to each sampling. Permitted medications that the participant normally takes can be taken as usual before a visit. 
j Additional blood samples (serum/PBMC) may need to be taken for additional/optional/future/vaccination research if the participant consents. If a participant 
who consents to this additional sampling receives a vaccination during the study, samples referred to in Section 8.2.9 should be taken. The closest visit that is at 
least 4 weeks after the vaccine was administered may be used. If this visit does not coincide with IPnV1, then another sample will also be taken at this visit. 
Serum samples only need to be taken when a vaccination is planned or after a vaccination has occurred. In addition, a whole-blood sample to isolate PBMCs 
will be collected at study entry and then approximately every 3 months throughout the study during a scheduled on-site visit, regardless of the vaccines a 
participant has received. 
k Titers of ADA and the presence of NAbs against efgartigimod will be measured in serum. Blood samples for plasma titer levels of ADA and NAbs against 
rHuPH20 will also be taken, but these will only be analyzed if needed for safety purposes. 
l A nasopharyngeal swab will be performed to sample nasal and throat mucosal cells. Participants should only be tested for SARS-CoV-2 if they have symptoms 
of COVID-19 or if they were in contact with a person who tested positive for SARS-CoV-2, unless local or site regulations have more stringent testing 
requirements. Participants may be retested as needed. See Section 10.6.  
m This activity is only for women of childbearing potential. See Section 10.5.2.1. 
n Training can continue until the participant or caregiver is ready to administer efgartigimod PH20 SC, to the satisfaction of the site staff (a minimum of 1 visit) 
before performing an administration under the supervision of site staff. Therefore, a minimum of 2 visits is required for a participant or caregiver to be 
considered competent to administer efgartigimod PH20 SC at home. Caregivers must sign the ICF before being trained in IMP administration.  
o The first dose administration of all TPs (TPnV1) must be performed on-site, even if the dose is self-administered or administered by the caregiver. Subsequent 
administrations in any TP (TPnV2/3/4) may be performed at home, if the participant or caregiver has been trained and is competent to perform IMP 
administration. When IMP administration is performed at home, the associated visit will be performed by phone. 
p When administration is performed at home, participant compliance with the efgartigimod PH20 SC dosing and administration schedule will be assessed by 
direct questioning at each phone visit. Any deviations from the planned dosage must be recorded. See Section 6.4. 
q When a participant is not on-site, they must record any observed injection site reaction in the patient diary. The investigator will evaluate all reported injection 
site reactions and decide whether the site reaction is classified and reported as an AE. 
r Adverse events (including ongoing AEs from the antecedent studies), use of concomitant therapies, use of rescue therapy, medical procedures performed on the 
participants, and hospitalizations will be collected from ICF signature until the last study-related activity. All vaccines received during the study should be 
recorded as concomitant medication. See Section 6.8 and Section 8.3. 
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2. 
INTRODUCTION 
Efgartigimod is a human immunoglobulin (Ig) G1 (IgG1)-derived Fc fragment that binds with 
nanomolar affinity to human neonatal Fc receptor (FcRn), developed for the treatment of 
generalized myasthenia gravis (gMG). Efgartigimod alfa IV (VYVGART) received regulatory 
approval in various jurisdictions for patients with gMG. The subject of this protocol is the SC 
formulation of efgartigimod, referred to as efgartigimod PH20 SC. 
2.1. 
Study Rationale 
The aim is to evaluate the long-term safety and tolerability of efgartigimod coformulated with 
recombinant human hyaluronidase PH20 (rHuPH20) administered subcutaneously (SC) 
(efgartigimod PH20 SC) and its efficacy in patients with gMG. As the SC formulation allows for 
self-administration, the study will explore the feasibility of self-administration and caregiver-
supported administration, the impact of efgartigimod PH20 SC on quality of life (QoL), 
treatment satisfaction, and mode of administration preference.  
The incidence and severity of adverse events (AEs), incidence of serious adverse events (SAEs), 
vital signs, and laboratory assessments of participants receiving efgartigimod PH20 SC 1000 mg 
will be evaluated over time, as per the primary objective. The SC formulation includes rHuPH20 
because the enzyme allows manual SC injection within a few minutes and using larger volumes 
than what is possible without rHuPH20. 
2.2. 
Background 
gMG is a rare, chronic, neuromuscular autoimmune disease caused by pathogenic IgGs targeting 
the neuromuscular junction (NMJ), producing reduced neuromuscular transmission and 
debilitating and potentially life-threatening muscle weakness and chronic fatigue. Generalized 
muscle weakness results in difficulties in mobility, speech, swallowing, vision, and respiration. 
Up to 20% of patients develop potentially life-threatening myasthenic crisis involving respiratory 
failure requiring mechanical ventilation.1,2 
ARGX-113 (efgartigimod) is an investigational antibody fragment and a first-in-class FcRn 
antagonist that is being evaluated for the treatment of patients with severe autoimmune diseases 
mediated by pathogenic IgG autoantibodies, including gMG. Approximately 90% of patients 
with gMG have detectable levels of IgG autoantibodies in the serum. Most commonly, these 
antibodies are against the acetylcholine receptor (AChR).3 Efgartigimod results in degradation of 
circulating disease-causing pathogenic antibodies by blocking FcRn. 
FcRn is present throughout life and expressed predominantly in endothelial cells and cells of 
myeloid lineage. FcRn has a specific role in IgG homeostasis, recycling all IgG subtypes, which 
rescues them from lysosomal degradation. This FcRn-mediated recycling results in the longer 
half-life and higher concentrations of IgG, including pathogenic IgG autoantibodies, compared to 
other Igs that are not recycled by FcRn. FcRn also promotes transcytosis of IgG into tissues. 
Additionally, FcRn recycles albumin using a site that is distinct from the IgG binding site. 
Efgartigimod is a human IgG1 antibody Fc fragment, a natural ligand of FcRn, engineered for 
increased FcRn affinity at both physiological and acidic pH. Efgartigimod outcompetes 
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endogenous IgG binding, preventing FcRn-mediated recycling of IgGs and increasing IgG 
degradation.  
The efficacy of efgartigimod IV based on the percentage of MG-ADL responders was 
demonstrated against placebo in study ARGX-113-1704. Further, there was a strong association 
between total IgG and AChR-Ab reductions and clinical response, as measured by the percentage 
of MG-ADL responders. This strong association was used to bridge from efgartigimod IV to 
efgartigimod PH20 SC in study ARGX-113-2001. This study showed noninferiority of the 
pharmacodynamic effect (as measured by IgG percent reduction at week 4) of efgartigimod 
PH20 SC 1000 mg compared with efgartigimod IV 10 mg/kg in participants with gMG after 1 
treatment cycle of 4 weekly administrations. 
Given efgartigimod’s mechanism of action of reducing IgG levels, the strong association 
between total IgG reduction and clinical response in patients with gMG, the SC formulation of 
efgartigimod PH20 SC may provide an alternative to efgartigimod 10 mg/kg IV, giving patients 
with gMG treatment optionality and flexibility. 
A detailed description of the chemistry, pharmacology, efficacy, and safety of efgartigimod is 
provided in the Investigator’s Brochure (IB).  
2.3. 
Benefit/Risk Assessment 
More detailed information about the known and expected benefits and risks and reasonably 
expected AEs of efgartigimod PH20 SC is provided in the current IB. 
2.3.1. 
Risk Assessment 
Overall, available data confirm that efgartigimod PH20 SC has been well tolerated across studies 
in different indications and has an acceptable safety profile.  
 
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Table 3: 
Potential Risks and Mitigation Strategies 
Potential 
Clinically 
Significant Risk  
Summary of Data/Rationale for Risk 
Mitigation Strategy 
Serious infection 
Efgartigimod reduces IgG levels, 
potentially hindering immune response 
and increasing the risk for infection. 
Exclude participants with clinically 
significant active infection not 
sufficiently resolved in the 
investigator’s opinion (Section 5.2).  
Infections are considered AESIs 
(Section 8.3.6). Monitor for infections 
and temporarily interrupt IMP dosing 
as specified in Section 7.1. 
Injection-related 
reactions 
All therapeutic proteins can elicit 
immune responses, potentially resulting 
in hypersensitivity or allergic reactions 
such as rash, urticaria, angioedema, 
serum sickness, and anaphylactoid or 
anaphylactic reactions.  
Monitor participants during 
administration and for 30 minutes 
thereafter for clinical signs and 
symptoms of injection-related 
reactions. Injection-related reactions 
are considered AEs of clinical interest 
(Section 8.3.7). 
Injection-site 
reactions 
Most AEs have been mild, transient 
injection-site reactions, including 
erythema, pain, bruising, pruritus, 
burning, tenderness, edema, induration, 
irritation, paresthesia, numbness, and 
rash. Moderate injection-site reactions 
occurring less frequently include 
burning, erythema, pain, and numbness. 
Mild to moderate headache is commonly 
reported. 
 
Localized injection-site reactions were 
observed in studies of efgartigimod with 
PH20 administered SC.  
Continuously monitor participants for 
injection-site reactions.  
Injection-site reactions are considered 
AEs of clinical interest 
(Section 8.3.7). 
AE=adverse event; AESI=adverse event of special interest; IgG=immunoglobulin G; IMP=investigational medicinal 
product; PH20=recombinant human hyaluronidase PH20 (rHuPH20); SC=subcutaneous(ly) 
2.3.2. 
Overall Benefit-Risk Conclusion 
More detailed information about the known and expected benefits and risks of efgartigimod 
PH20 SC and reasonably expected AEs can be found in the current version of the IB. 
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3. 
OBJECTIVES AND ENDPOINTS 
Table 4: 
Study ARGX-113-2002 Objectives and Endpoints 
Objectives 
Endpoints 
Primary 
 
• To evaluate the long-term safety and 
tolerability of efgartigimod PH20 SC in 
participants with gMG 
• Incidence and severity of AEs, incidence 
of SAEs, and AEs of special interest 
(AESIs), and changes in laboratory test 
results, physical examination results, 
vital signs, and electrocardiogram results 
Secondary 
 
• To evaluate the impact of efgartigimod 
PH20 SC on disease severity 
• Myasthenia Gravis Activities of Daily 
Living (MG-ADL) total score changes 
from baseline and cycle baseline over 
time by cycle 
• To evaluate the effect of efgartigimod 
PH20 SC on PD 
• Percentage reduction in levels of total 
immunoglobulin G (IgG) from baseline 
and cycle baseline over time by cycle 
• Percentage reduction of anti-
acetylcholine receptor antibodies 
(AChR-Ab) from baseline and cycle 
baseline over time by cycle in AChR-Ab 
seropositive participants 
• To evaluate the PK of efgartigimod PH20 
SC 
• Efgartigimod serum concentrations 
• To evaluate the immunogenicity of 
efgartigimod PH20 SC 
• Incidence and prevalence of anti-drug 
antibodies (ADAs) to efgartigimod over 
time  
• Incidence and prevalence of neutralizing 
antibodies (NAbs) against efgartigimod 
over time 
• Incidence and prevalence of ADAs to 
rHuPH20 over time  
• Incidence and prevalence of NAbs 
against rHuPH20 over time 
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• To evaluate the impact of efgartigimod 
PH20 SC on the QoL of the participants 
• Changes in total Myasthenia Gravis 
Quality of Life Questionnaire (15-item 
scale revised) (MG-QoL15r) from 
baseline and cycle baseline by cycle 
• Changes in EuroQoL 5 Dimensions 
5-Level (EQ-5D-5L) visual analog scale 
(VAS) score from baseline and cycle 
baseline over time by cycle 
• EQ-5D-5L responses to 5 dimensions (ie, 
mobility, self-care, usual activities, 
pain/discomfort, anxiety/depression) over 
time by cycle 
• To evaluate feasibility of 
self-administration of efgartigimod PH20 
SC 
• Number and percentage of participants 
who performed self-administration at 
home over time by cycle 
• Number and percentage of caregivers 
who administered the injection to the 
participant at home over time by cycle 
• Number of training visits needed for the 
participant or caregiver to be competent 
to start administering efgartigimod 
PH20 SC 
• Number and percentage of self- or 
caregiver-supported study drug 
administration among all study treatment 
visits at home 
Exploratory 
 
• 
 
 
 
• 
 
 
 
 
 
• 
 
 
 
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4. 
STUDY DESIGN 
4.1. 
Overall Design 
• This is a phase 3, multicenter, long-term, single-arm, open-label study to evaluate the 
long-term safety and tolerability of efgartigimod PH20 SC 1000 mg. The clinical 
efficacy, PD, PK, immunogenicity, impact on the QoL of the participants, treatment 
satisfaction, mode of administration participant preference, and the feasibility of 
self-administration and caregiver-supported administration will also be assessed. 
• The total study duration is from the participant’s first visit in this study until, at the 
latest, 31 Dec 2024 (See Section 1.1):  
− Year 1: 3-week TPs of once weekly injections, repeated as needed with at least 28 
days between TPs 
− Year 2 onward: 3-week TPs of once weekly injections. It is recommended to have 
IPs of at least 28 days, but a subsequent treatment period can be administered 
earlier based on clinical evaluation at the discretion of the investigator. A minimal 
interval of 7 days after the last IMP administration of the previous cycle must be 
maintained.  
• The primary target population is adult patients with gMG who have previously 
participated in studies ARGX-113-2001 or ARGX-113-1705.  
− Study ARGX-113-2001 is a phase 3, randomized, open-label, parallel-group study 
comparing the PD, PK, efficacy, safety, tolerability, and immunogenicity of 
efgartigimod PH20 SC and efgartigimod IV in patients with gMG. Participants 
either receive efgartigimod PH20 SC 1000 mg or efgartigimod IV 10 mg/kg q7d 
for a total of 4 doses, after which there is a follow-up period of approximately 50 
days.  
− Study ARGX-113-1705 is a phase 3, single-arm, open-label, multicenter 
extension study evaluating the long-term safety and tolerability of efgartigimod 
IV in patients with gMG. Participants receive efgartigimod IV 10 mg/kg q7d for a 
total of 4 infusions, followed by an intertreatment cycle of variable length 
dependent on the patient’s clinical response to efgartigimod. Participants may 
continue this cycle for up to 3 years, receiving efgartigimod IV based on their 
clinical need. 
• Participants must be receiving concomitant medication for gMG to enter the study 
and they must be on a stable dose of concomitant medication to be eligible for 
retreatment. Participants who have recently altered their concomitant medication 
dosage will start the study with an IP. See Section 6.8.2. 
• At study entry, participants will be evaluated for the need of retreatment. Refer to the 
SoA in Section 1.3 for timing of retreatment. 
• Efgartigimod PH20 SC will be administered by injection into the abdominal 
subcutaneous tissue or into the subcutaneous tissue of another appropriate injection 
site. Participants or their caregivers will be trained in IMP administration. A caregiver 
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is a person of legal age from the participant’s social network (eg, family, relatives, 
friends) introduced by the participant. After signing an informed consent form (ICF) 
and receiving the necessary training, the caregiver can administer the SC injections to 
the participant. If the participant or caregiver completes the training to the satisfaction 
of the investigator, the participant or caregiver will be permitted to administer the 
investigational medicinal product (IMP). 
• Participants and their caregivers must complete the training to the satisfaction of the 
site staff (a minimum of 1 site visit) before (self-)administering efgartigimod PH20 
SC under the supervision of the site staff. Participants and caregivers who were in the 
SC arm in antecedent study ARGX-113-2001 and considered competent to 
(self-)administer may (self-)administer efgartigimod PH20 SC at home as of the 
second visit of the first TP. Participants and caregivers from the IV antecedent studies 
who are considered competent to (self-)administer may do so at home as of the 
second visit of the second TP onward. All participants must come to the site for the 
first administration of a TP, even if the participant or caregiver administers. 
4.2. 
Scientific Rationale for Study Design 
The aim is to evaluate the long-term safety and tolerability of efgartigimod PH20 SC 1000 mg 
and its efficacy in patients with gMG. Efgartigimod PH20 SC will include rHuPH20 because the 
enzyme facilitates the SC delivery of volumes greater than ~2 mL and may increase the 
absorption and dispersion of efgartigimod. rHuPH20 depolymerizes hyaluronan under 
physiologic conditions and acts as a permeation enhancer, allowing for a larger volume to be 
injected with limited swelling or pain.4 
As per the primary objective (Section 3), long-term safety and tolerability will be assessed by 
measuring the incidence and severity of TEAEs, including SAEs, AESIs, electrocardiogram 
(ECG) results, and clinical laboratory assessments over time. These metrics provide a broad view 
of potential safety concerns and allow a more detailed safety profile for efgartigimod PH20 SC. 
An open-label, single-arm design allows for accrual of long-term safety data over multiple TPs 
to verify the overall safety and tolerability profile of the SC formulation of efgartigimod. 
IgG autoantibodies lead to gMG symptoms, resulting from destruction of important molecules in 
the NMJ, including AChR. Total IgG levels and levels of AChR-Abs will be evaluated in the 
first year of the study as objective surrogate measures for the treatment efficacy of efgartigimod 
in gMG. Clinical efficacy will be measured by the MG-ADL total score, which is a well-
established measure for assessing disease severity. Furthermore, study ARGX-113-1704 showed 
that reductions in the MG-ADL total score were consistent with reductions in levels of total IgG 
and AChR-Abs and followed a similar time course. Any effect on the QoL of the participants 
will be measured using the MG-QoL15r and EQ-5D-5L assessments, which are standardized 
assessments for quality of life related to gMG symptoms and generic health status, respectively. 
 
 
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4.3. 
Justification for Dose 
The efgartigimod PH20 SC dose selected targets a similar total IgG reduction compared to the 
efgartigimod IV 10 mg/kg dose, anticipating a similar clinical response. PK/PD modeling 
indicated that weekly or biweekly doses of efgartigimod PH20 SC 1000 mg result in a 
comparable effect on IgG levels when compared to efgartigimod IV 10 mg/kg administered q7d 
or biweekly (q2w). In a phase 3 study in participants with gMG (ARGX-113-1704), 
administration of efgartigimod IV 10 mg/kg q7d for 4 infusions achieved near-maximal total IgG 
reduction, resulted in a reduction of pathogenic autoantibodies, and was associated with clinical 
efficacy in participants with gMG. 
A proportion of participants have clinically significant worsening of symptoms at the end of the 
required minimum 28-day IP. Treatment management aims at minimizing fluctuations in disease 
severity. Therefore, some participants may benefit from earlier initiation of the subsequent cycle. 
Thus, earlier initiation of the next cycle will be allowed from the second year of treatment 
onward. This adaptation is not expected to raise any safety issues. Efgartigimod has been tested 
in once weekly and biweekly treatment regimens in other indications such as ITP and PV, and no 
safety concerns were identified with this treatment regimen, compared to the safety profile in 
cyclic dosing. Refer to the current IB for more details. 
4.4. 
End of Study Definition 
The end of the study is defined as the date of the last participant’s last visit. 
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5. 
STUDY POPULATION 
Prospective approval of protocol deviations to recruitment and enrollment criteria, also known as 
protocol waivers or exemptions, is not permitted. 
5.1. 
Inclusion Criteria 
Participants are eligible to be included in the study only if all of the following criteria apply: 
1. Must be capable of giving signed informed consent as described in Section 10.1.3, which 
includes compliance with the requirements and restrictions listed in the ICF and in this 
protocol 
2.  Previously participated in antecedent studies ARGX-113-2001 or ARGX-113-1705 and 
are eligible for rollover as defined by: 
a. For ARGX-113-2001 
− Completed the study and performed the EoS visit, or 
− Were discontinued from study treatment for reasons other than pregnancy or a 
life-threatening SAE. Receiving rescue therapy is not exclusionary unless given in 
a response to a life-threatening situation 
b. For ARGX-113-1705 
− Performed the end of part A, or 
− Started Part B, received the previous dose of efgartigimod IV at least 30 days 
prior to entry into this study, completed at least 1 year of study ARGX-113-1705, 
and performed the early discontinuation visit in ARGX-113-1705 
− Did not have 3 consecutive treatment failures in ARGX-113-1705 Part A, even if 
the participant received rescue therapy (unless rescue therapy was given in 
response to a life-threatening situation). Treatment failure is defined as the 
absence of a decrease of at least 2 points in total MG-ADL score compared to the 
subsequent TP baseline in at least 50% of the assessments 
− Are still receiving concomitant gMG medication. Participants who have stopped 
taking any concomitant medication for gMG are not eligible for rollover 
− Participants may rollover from ARGX-113-1705 until recruitment for this study is 
closed 
3. Contraceptive use should be consistent with local regulations regarding the methods of 
contraception for those participating in clinical studies and: 
a. Male participants  
− Refer to Section 10.5.2.2. 
b. Female participants 
− WOCBP (defined in Section 10.5.1) must have a negative urine pregnancy test at 
baseline before IMP can be administered. 
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− The contraceptive requirements for WOCBP are described in Section 10.5.2. 
5.2. 
Exclusion Criteria  
Participants are excluded from the study if any of the following criteria apply: 
1. The participant was discontinued early from studies ARGX-113-2001 or 
ARGX-113-1705, unless the reason for discontinuation from study ARGX-113-1705 was 
to rollover into study ARGX-113-2002 
a. Participants who, in the investigator’s judgment, are not benefiting from efgartigimod 
IV in study ARGX-113-1705 Part B are not eligible for rollover into 
ARGX-113-2002 
2. Are pregnant or lactating, or intend to become pregnant during the study or within 
90 days after the last dose of IMP 
3. Have any of the following medical conditions: 
a. Clinically significant uncontrolled chronic bacterial, viral, or fungal infection at 
rollover 
b. Any other known autoimmune disease that, in the opinion of the investigator, would 
interfere with accurate assessment of clinical symptoms of myasthenia gravis or put 
the participant at undue risk 
c. History of malignancy unless deemed cured by adequate treatment with no evidence 
of reoccurrence for ≥3 years before the first administration of IMP. Participants with 
the following cancers can be included at any time: 
− adequately treated basal cell or squamous cell skin cancer 
− carcinoma in situ of the cervix 
− carcinoma in situ of the breast 
− incidental histological findings of prostate cancer (TNM classification of 
malignant tumors stage T1a or T1b) 
d. Clinical evidence of other significant serious diseases, or the participant has had a 
recent major surgery, or who have any other condition that, in the opinion of the 
investigator, could confound the results of the study or put the participant at undue 
risk 
4. Received a live-attenuated vaccine within 28 days prior to study entry or plan to receive a 
live-attenuated vaccine during the study 
5. Had a known hypersensitivity reaction to efgartigimod, rHuPH20, or any of its excipients 
5.3. 
Lifestyle Considerations 
Participants will need to be fasted for each on-site visit at which safety laboratory assessments 
will be performed. Fasted is defined as no food or drink for at least 8 hours prior to the visit. 
Permitted medications that the participant normally takes can be taken as usual before a visit. 
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5.4. 
Screen Failures 
Eligibility to rollover must be verified at the last visit of the antecedent studies ARGX-113-2001 
or ARGX-113-1705, which acts as the first visit of this study. 
Screen failures are defined as participants who consent to participate in the clinical study but are 
not subsequently entered in the study. A minimal set of screen failure information is required to 
ensure transparent reporting of screen failure participants to meet the Consolidated Standards of 
Reporting Trials (CONSORT) publishing requirements and to respond to queries from regulatory 
authorities. Minimal information includes demography, screen failure details, eligibility criteria, 
and any SAE. 
Results from assessments in the antecedent studies should be used to determine eligibility. 
Individuals who do not meet the criteria for participation in this study (screen failure) may not be 
rescreened.  
5.5. 
Criteria for Temporarily Delaying Administration of Study 
Intervention 
Delaying the administration of the IMP must occur if it is deemed in the best interest of the 
participant, as determined by the investigator. If a dose cannot be administered within a visit 
window as specified in the SoA (Section 1.3), then that dose will be skipped. See Section 7.1.1. 
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6. 
STUDY INTERVENTION(S) AND CONCOMITANT THERAPY 
Study intervention is defined as any investigational intervention(s), marketed product(s), 
placebo, or medical device(s) intended to be administered to a study participant according to the 
study protocol. 
6.1. 
Study Intervention(s) Administered 
 
Table 5: 
Study Intervention Administered 
Treatment Group 
Efgartigimod PH20 SC 
Intervention name 
Efgartigimod solution for SC injection 
 mg/mL coformulated with rHuPH20  
Type  
Biologic 
Dose formulation 
Efgartigimod drug product of 
 mg/mL for 
a fixed dose of 1000 mg for SC injection 
coformulated with 
 U/mL rHuPH20 
Unit dose strength(s) 
 mg/mL 
Dosage level(s) 
1000 mg q7d for a total of 4 injections in a 
TP, with multiple TPs possible depending on 
clinical effect 
Route of administration 
SC injection 
Use 
Investigational 
IMP and NIMP 
IMP 
Sourcing 
Provided centrally by the sponsor 
Packaging and labeling 
The IMP will be provided in glass vials and 
will be packed and labeled in secondary 
boxes. Each glass vial and box will be labeled 
as per country requirement.  
6.2. 
Preparation/Handling/Storage/Accountability 
For detailed instructions for preparation, handling, storage, and accountability, please refer to the 
pharmacy manual and applicable guidance materials for home administrations. Each participant 
or caregiver will receive a specific training for IMP administration and a manual on preparation, 
handling, storage and administration of the IMP. 
6.2.1. 
Preparation 
Efgartigimod for SC administration will be provided as a sterile, clear to opalescent, yellowish 
solution for injection in glass vials. 
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The IMP will be manufactured in accordance with Good Manufacturing Practice regulations. 
6.2.2. 
Handling 
The investigator or designee must confirm appropriate temperature conditions have been 
maintained during transit for all IMP received and any discrepancies are reported and resolved 
before use of the IMP. 
Only participants enrolled in the study may receive IMP and only authorized site staff may 
supply the IMP. IMP administration must be performed by site staff or by an adequately trained 
participant or caregiver.  
Home administration by the participant or caregiver is permitted once they are considered 
competent to do (refer to Section 4.1). 
6.2.3. 
Storage 
The IMP will be supplied to the pharmacy at the designated investigational site by and under the 
responsibility of the sponsor’s designated IMP supply vendor. The investigator will be provided 
with the European Union qualified person release documents. 
All study intervention must be stored in a secure, environmentally controlled, and monitored 
(manual or automated) area in accordance with the labeled storage conditions with access limited 
to the investigator and authorized site staff until the study intervention is received by the 
participant. 
The IMP must be stored refrigerated (2°C to 8°C or 35°F to 46°F) in its secondary packaging. It 
should not be exposed to freezing temperature or shaken, and it should be protected from direct 
sunlight during storage at the clinical site and when the participant is storing the IMP at home. 
The investigator (or designee) is responsible for the correct and safe storage of the IMP assigned 
to the clinical site before the IMP is given to the participant for home administration. While at 
the clinical site, the IMP must be stored in a locked, secure storage facility maintained within the 
appropriate temperature ranges, with access limited to those individuals authorized to dispense 
the IMP. 
Once the participants have the IMP outside of the clinical site, they are responsible for the 
correct storage of the IMP. The investigator (or his/her designee) must directly ask the 
participant if the IMP has been stored correctly. Participants will be instructed to contact the site 
if they think there is a problem with the storage conditions at home. 
6.2.4. 
Accountability 
The investigator, institution, or the head of the medical institution (where applicable) is 
responsible for IMP accountability, reconciliation, and record maintenance (ie, receipt, 
reconciliation, and final disposition records). 
When the IMP is being used in home administration, the investigator or his/her designee must 
directly ask the participant to ensure that the IMP is only being taken by the participant and that 
it is being properly stored at home. All IMP vials must be returned to the site for accountability, 
regardless of whether they were used. 
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6.3. 
Measures to Minimize Bias: Randomization and Blinding 
As this is an open-label, single-arm study, no randomization or blinding will be performed.  
6.4. 
Study Intervention Compliance 
Participants and/or their caregivers will receive specific training for IMP administration of 
efgartigimod PH20 SC and guidance materials on preparation, handling, storage, and 
administration of the IMP (refer to Section 4.1). 
When the study intervention is administered at home by the participant or caregiver, compliance 
with study intervention will be assessed at each visit, including phone visits. Compliance will be 
assessed by direct questioning during the visits and documented in the source documents and the 
electronic case report form (eCRF). Deviation(s) from the prescribed dosage regiment should be 
recorded. 
A record of the quantity of efgartigimod PH20 SC dispensed to and administered by each 
participant must be maintained and reconciled with study intervention and compliance records. 
Intervention start and stop times and dates, including dates for intervention delays will also be 
recorded by the site staff when administration is performed at the site and by the participant 
when administration is performed at home. At every on-site visit, the study staff must review the 
administration log and patient diary with the participant. 
The investigator should promote treatment compliance by stating that compliance is necessary 
for the participant’s safety and the validity of the study. The prescribed dose, timing, and mode 
of administration cannot be changed. Site staff will contact the participants for the scheduled 
phone visits and ensure that the participant is compliant with the IMP administration schedule. 
All dates, start and end times of IMP administration, and any deviations from the intended 
regimen must be recorded in the administration log and the eCRF. 
Participants will be provided with an administration log, where they will record when the IMP 
was administered at home and if there were any issues with the IMP administration. Participants 
will also receive a patient diary to record any AEs (including injection site reactions) that have 
occurred, what concomitant medication they have been taking, any hospitalizations, emergency 
room (ER) admissions, and intensive care unit (ICU) admissions. Completed diaries have to be 
provided to the site staff whenever the participant visits the site. Data collected from the diaries 
will need to be entered into the eCRF by the site staff. 
A sponsor’s designated contract research organization (CRO) monitor will review the pharmacy 
records at each site including the drug accountability and dispensing records on which the 
pharmacist or designated person should record all IMP released for participant use. The 
sponsor’s designated CRO monitor will compare the dispensing record and vials with the 
individual participant’s identifiers, kit number, and visit schedule to confirm that the participant 
received the correct treatment and dose, and that the dosing schedule is correct. The designated 
CRO monitor will also review records if the IMP administration is performed at home. 
Errors that are identified will be communicated to the site personnel to ensure that the errors are 
not repeated. The sponsor’s designated CRO monitor’s report will include details of any missed 
doses, errors in dose, treatment or scheduling errors, and the associated explanations. If it is 
determined that a participant or their caregiver committed an error in administration, then the 
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participant or the caregiver will need to complete the administration training again. The site staff 
will then determine if the participant and caregiver are competent to continue administration 
without supervision. All supplies and pharmacy documentation must be made available 
throughout the study for the sponsor’s designated CRO monitor to review. 
6.4.1. 
Handling Missed Doses of the IMP 
All efforts will be made to ensure that the participant receives all administrations of the IMP in 
the scheduled dosing window. If a participant cannot receive the dose within the scheduled 
dosing window, that dose must be skipped. Participants who miss doses will be allowed to 
continue in the study. Dosing should resume in the next scheduled dosing window, unless there 
are medical concerns that indicate IMP administration would put the participant at undue risk.  
6.4.2. 
Protocol Deviations 
The investigator should not implement any deviation from or changes to the approved protocol, 
except when necessary to eliminate an immediate hazard to study participants, or when the 
change involves only logistical or administrative aspects of the study (eg, change of telephone 
numbers). The investigator (or designee) should document and explain a deviation from the 
approved protocol. 
6.5. 
Dose Modification 
No dose modification is planned for this study. 
6.5.1. 
Retreatment Criteria 
A participant may be retreated if the investigator determines that the participant’s condition has 
deteriorated due to gMG symptoms and if the participant agrees to be retreated. 
The investigator may start a new TP during an on-site IP visit. In this instance, the IP visit 
becomes the first visit of the new TP (TPnV1). No activities will be duplicated. If a participant 
thinks they may need retreatment between on-site visits, they may contact the investigator to 
discuss retreatment and schedule the first visit of the new TP (TPnV1). 
The participant must meet all of the following criteria to be eligible for retreatment: 
• The participant completed the previous TP 
• The participant could benefit from retreatment according to the investigator’s 
judgment 
• There is no clinical or laboratory evidence of any concomitant disease that could 
confound the results of the study or put the participant at undue risk (eg, infection) 
• At least 28 days has elapsed since the participant received any kind of rescue therapy 
• For year 1: 
− At least 28 days has elapsed between treatment periods (ie, between the last dose 
of the previous TP and the first dose of the next TP)  
• For year 2 onward:  
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− At least 7 days has elapsed between treatment periods (ie, between the last dose of 
the previous TP and the first dose of the next TP). It is recommended to have 
intertreatment periods (IPs) of at least 28 days, but a subsequent treatment period 
can be administered earlier based on clinical evaluation at the discretion of the 
investigator.  
• There must be at least 4 weeks left in the study for the participant, so that a full TP 
and the EoS visit can be performed.  
6.6. 
Continued Access to IMP After the End of the Study 
At the end of the study, argenx cannot guarantee continued access for participants but will 
comply with all local laws and regulations. 
6.7. 
Treatment of Overdose 
For this study, a variation of less than 10% of the amount of efgartigimod PH20 SC that should 
be injected for each administration will not be considered an overdose or medication error. A 
variation of greater than 10% of the intended amount of efgartigimod PH20 SC will be 
considered a medication error and an overdose, if applicable, regardless of whether any AEs 
occur. 
An overdose is defined as a deliberate or accidental administration of IMP to a participant at a 
dose more than 10% that was assigned to that participant per the study protocol.  
A medication error is any preventable incident that may cause or lead to inappropriate IMP use 
or participant harm while the IMP is in the care of the health care professionals. Such an incident 
may be due to health care professional practice, product labeling, packaging and preparation, 
administration procedures, and/or systems, including prescribing, order communication, 
nomenclature, compounding, dispensing, distribution, administration, education, monitoring, 
and/or use.  
In case of a suspected overdose and/or medication error, the participant must be treated 
according to standard medical practice based on the investigator’s judgment. The suspected 
overdose and/or medication error must be documented, with the quantity of the excess dose, as 
well as any observed AEs that are associated with the overdose.  
6.8. 
Concomitant Therapy 
Any medication or vaccine (including over-the-counter or prescription medicines, recreational 
drugs, vitamins, or herbal supplements) that the participant is receiving at the time of enrollment 
or receives during the study must be recorded in the eCRF along with: 
• Reason for use 
• Dates of administration including start and end dates 
• Dosage information including dose and frequency 
• Brand name 
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The medical monitor should be contacted if there are any questions regarding concomitant or 
prior therapy. 
6.8.1. 
Prior Medication and Procedures 
Clinically relevant ongoing medication and procedures received by the participant must be 
recorded in the eCRF, including the start dates. Any information on prior medication from the 
antecedent studies ARGX-113-2001, ARGX-113-1704, and ARGX-113-1705 may be used in the 
analysis. For participants rolling over from ARGX-113-1705, all available vaccination history 
should be recorded. Any vaccination information that the participant or their caregiver can 
remember should be recorded in the eCRF, with the brand name of the vaccine and date of 
vaccination, if possible. When a vaccine requires multiple injections (eg, influenza vaccine, 
tetanus vaccination, and booster), only the most recent vaccination must be recorded. 
6.8.2. 
Permitted Concomitant Medication and Procedures 
At study entry, participants are required to be on concomitant therapy for gMG, as they were in 
the antecedent studies. Permitted concomitant therapy for gMG includes: 
• Nonsteroidal immunosuppressant (NSIDs) (eg, azathioprine, methotrexate, 
cyclosporine, tacrolimus, mycophenolate mofetil, and cyclophosphamide) 
• Steroids 
• Acetylcholinesterase (AChE) inhibitors 
To be retreated at study entry, participants must be on a stable dose of concomitant therapy for 
gMG. Therefore, participants entering this study from ARGX-113-1705 that have recently 
adjusted their concomitant medication will have to wait to be retreated in this study for the 
following time periods after changing their concomitant medication: 
• NSIDS: 3 months 
• steroids: 1 month 
• AChE inhibitors: 2 weeks 
In the first year, participants will be allowed to reduce the dose of a corticosteroid, an NSID, or 
an AChE inhibitor during IPs, but only after the first IP visit following a TP.  
During the second year of the study, there will be no restrictions on changes to any concomitant 
gMG treatment.  
All changes in concomitant gMG treatment and the reason for the change must be recorded in the 
eCRF. 
Throughout the entire study, participants may be treated with plasma exchange (PLEX), Ig 
therapy or immunoadsorption (as a combination or monotherapy) as rescue therapy a maximum 
of 3 times per year if it is not for a life-threatening condition (see Section 6.8.3). 
Participants are allowed to receive vaccines that do not use live or live-attenuated biological 
material. Any inactivated subunit, polysaccharide, or conjugate vaccine is allowed at the 
discretion of the investigator and when administered at least 48 hours predose or 48 hours 
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postdose of the IMP. Any vaccination done during the study should be recorded in the eCRF 
with the brand name of the vaccine and the date of vaccine administration (see Section 8.2.9). 
Standard therapies for concurrent medical conditions are permitted if they are not listed as 
prohibited in Section 6.8.3. 
6.8.3. 
Prohibited Medications and Procedures 
If any of the following prohibited therapies are used, participants must be discontinued from the 
study: 
• any monoclonal antibody 
• other experimental/study IMP 
• live or live-attenuated vaccines 
In the first year of the study, participants are also not allowed to do any of the below activities. 
However, participants will not be discontinued from the study in case of a protocol deviation due 
to the following prohibited activities: 
• increase the dose or frequency of corticosteroids 
• start a new type of steroids 
• increase the dose or frequency of an NSID 
• start a new NSID 
• increase the dose or frequency of an AChE inhibitor 
• decrease the dose or frequency of a corticosteroid, an NSID, or an AChE inhibitor 
from TPnV1 through IPnV1 
6.8.4. 
Rescue Therapy 
PLEX, Ig therapy, immunoadsorption, an increased dose of the current corticosteroid, or the use 
of a different corticosteroid used as a monotherapy or in combination with another therapy are 
considered rescue therapy if both of the following conditions apply: 
1. The treating physician believes that the participant’s health is in jeopardy if rescue 
therapy is not provided, and 
2. The participant is deteriorating clinically according to the protocol-defined criteria, which 
includes at least 1 of the following: 
a. new or worsening of respiratory/bulbar symptoms, or 
b. at least a 2-point increase in any individual nonocular item on the MG-ADL scale 
compared to the previous visit 
The date and time of rescue medication administration, and the name, dosage regimen, and 
response to the rescue medication will be recorded in the eCRF. Prior to administration of rescue 
therapy, the MG-ADL total score should be recorded if possible. 
Participants who receive rescue therapy under the previously listed conditions will not be 
discontinued from the study unless rescue therapy is given in response to a life-threatening 
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situation. Participants may not receive PLEX, Ig therapy, or immunoadsorption more than 
3 times per year. When rescue therapy is needed, what therapy was used and the response to that 
therapy must be documented in the eCRF. The MG-ADL total score will be used to measure the 
response to the therapy at the safety follow-up (SFU) visit.  
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7. 
IMP DISCONTINUATION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL 
7.1. 
IMP Discontinuation 
It may be necessary for a participant to permanently discontinue IMP. If IMP is permanently 
discontinued, the participant will not remain in the study (see Section 7.2). 
7.1.1. 
Temporary Discontinuation of Study Intervention 
Temporary discontinuation of study intervention is defined as an interruption of only the current 
TP. Participants may have a temporary discontinuation of the study intervention without being 
required to discontinue early from the study. Participants could have a temporary discontinuation 
from the study due to a temporary medical condition that puts the participant at undue risk (ie, 
symptoms of infection). These participants may still be eligible for additional doses of 
efgartigimod PH20 SC. If a dose cannot be administered within a visit window as specified in 
the SoA (Section 1.3), then that dose will be missed (Section 6.4.1), and the treatment 
discontinuation and reason for the missed doses will be documented. The next planned IMP dose 
can be administered to the participant at the next scheduled TP visit if the investigator 
determines that the undue risk has been resolved. The participant must continue to participate in 
all remaining TP visits, regardless of whether the IMP will be administered. During the first year 
of the study, if the last dose(s) of a TP are missed, a new TP can start only after at least 28 days 
have elapsed since the last dose of efgartigimod PH20 SC was administered. During the second 
year of the study onward, if the last dose(s) of a TP are missed, a new TP can start only after at 
least 7 days have elapsed since the last dose of efgartigimod PH20 SC was administered. 
Participants can remain in the study regardless of how many doses are missed. 
7.2. 
Participant Discontinuation/Withdrawal From the Study 
Early discontinuation from the study is defined as the permanent cessation of further 
participation in the study prior to its planned completion.  
The reason for early discontinuation from the study will be clearly documented by the 
investigator. 
A participant may withdraw from the study at any time at his/her own request or may be 
withdrawn at any time at the discretion of the investigator for safety, behavioral, or compliance 
reasons.  
See Section 1.3 for data to be collected at the time of study discontinuation and follow-up and for 
any evaluations that need to be completed.  
Participants who discontinue early from the study at a study visit should perform the activities 
for the end of treatment (ET) visit if 49 days (±2 days) has not elapsed since the last dose of 
efgartigimod PH20 SC. These participants will not receive any further administration of 
efgartigimod PH20 SC during the study and will return for the SFU visit at least 49 ±2 days after 
the last dose administration. If 49 ±2 days has already elapsed since the last dose of efgartigimod 
PH20 SC, then this visit becomes the SFU visit and the SFU visit activities must be performed. 
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Participants who discontinue early from the study between visits should perform the SFU visit at 
least 49 ±2 days after the last dose of efgartigimod PH20 SC. If 49 ±2 days has already elapsed, 
then the SFU visit will be planned as soon as possible. 
The participant will be permanently discontinued from both the study intervention and from the 
study at that time.  
If the participant withdraws consent for disclosure of future information, the sponsor may retain 
and continue to use any data collected before such a withdrawal of consent. 
If a participant withdraws from the study, he/she may request destruction of any samples taken 
and not tested, and the investigator must document this in the study records and inform the 
sponsor as soon as possible. 
Participants must be discontinued from the study and complete the ET visit (if applicable) and 
the SFU visit at least 49 ±2 days after the last administered dose and as specified in the SoA, 
(Section 1.3) if: 
• the investigator determines it is in the participant’s best interest; discussion with the 
sponsor’s medical director is encouraged prior to discontinuation 
• the participant receives prohibited medication (Section 6.8.3) 
• the participant receives rescue therapy in response to a life-threatening situation 
(Section 6.8.4) 
• the participant receives rescue therapy more than 3 times per year 
• a severe hypersensitivity reaction to the IMP occurs 
• the participant is pregnant 
• the sponsor requests discontinuation (eg, following DSMB advice, see Section 
10.1.5.1) 
• participant develops a new or recurrent malignancy except for basal cell carcinoma of 
the skin, regardless of relationship 
7.3. 
Lost to Follow-up 
A participant will be considered lost to follow-up if he/she repeatedly fails to return for 
scheduled visits and is unable to be contacted by the study site. 
The following actions must be taken if a participant fails to return to the clinic for a required 
study visit: 
• The site must attempt to contact the participant and reschedule the missed visit as 
soon as possible and counsel the participant on the importance of maintaining the 
assigned visit schedule and ascertain whether or not the participant wishes to and/or 
should continue in the study. 
• Before a participant is deemed lost to follow-up, the investigator or designee must 
make every effort to regain contact with the participant (where possible, 3 telephone 
calls and, if necessary, a certified letter to the participant’s last known mailing 
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address or local equivalent methods). These contact attempts should be documented 
in the participant’s medical record. 
• Should the participant continue to be unreachable, he/she will be considered to have 
withdrawn from the study.  
• Site personnel, or an independent third party, will attempt to collect the vital status 
information of the participant within legal and ethical boundaries for all participants 
randomized, including those who did not get study intervention. Public sources may 
be searched for vital status information. If vital status is determined as deceased, this 
will be documented and the participant will not be considered lost to follow-up. 
Sponsor personnel will not be involved in any attempts to collect vital status 
information. 
Discontinuation of specific sites or of the study as a whole are handled as part of Section 10.1.9. 
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8. 
STUDY ASSESSMENTS AND PROCEDURES 
Study procedures and their timing are summarized in the SoA (Section 1.3). Protocol waivers or 
exemptions are not allowed. 
Immediate safety concerns should be addressed by the site staff upon occurrence or awareness. 
The investigator may decide whether to discontinue the IMP. If possible, the sponsor should be 
involved in the decision. 
Adherence to the study design requirements, including those specified in the SoA (Section 1.3), 
is essential and required for study conduct. 
At study entry, all eligibility assessments should be performed after obtaining informed consent. 
When a protocol-required procedure cannot be performed, the investigator will document the 
reason, and any corrective and preventative actions that he/she has taken to ensure that the 
protocol processes are adhered to in the source documents. The study team should be informed 
of these incidents in a timely manner. These incidents will be considered a protocol deviation 
and will be recorded accordingly.  
The investigator must confirm that potential participants meet all eligibility criteria. The 
investigator will record details of all participants to confirm eligibility. 
8.1. 
Efficacy Assessments 
Planned time points for all efficacy assessments are provided in the SoA (Section 1.3). Clinical 
efficacy will be measured using the MG-ADL scale and quality of life will be measured using 
the MG-QoL15r and EQ-5D-5L.5,6 
8.1.1. 
MG-ADL 
The MG-ADL is an 8-item patient-reported scale that assesses MG symptoms and their effects 
on daily activities. It evaluates a participant’s capacity to perform different activities in their 
daily life, including talking, chewing, swallowing, breathing, brushing their teeth, combing their 
hair, or getting up from a chair. The MG-ADL also assesses double vision and eyelid droop. It is 
a discrete quantitative variable in which the 8 items are rated by the participant on a scale of 
0 to 3. The total score can range from 0 to 24, with higher total scores indicating more 
impairment. The MG-ADL assessment does not require any equipment to perform. The scoring 
of the MG-ADL should be performed by a trained and certified evaluator. If possible, the same 
evaluator should administer the MG-ADL for a given participant throughout the study. It is 
recommended to perform the MG-ADL scale prior to all other assessments. 
8.1.2. 
MG-QoL15r 
The MG-QoL15r is a 15-item survey of a patient’s perceived health-related quality of life and 
addresses attributes known to be meaningful to a patient with gMG, such as psychological 
well-being and social functioning.  
The patient assesses statements using a 3-point (0–2) Likert scale on the following domains: 
• mobility (9 items) 
• symptoms (3 items) 
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• general contentment (1 item) 
• emotional well-being (2 items) 
Each item will be participant-scored using a 3-point severity scale ranging from 0 (not at all) to 2 
(very much), with a maximum possible score of 30. The MG-QoL15r is helpful in determining 
the participant’s perception of the extent and dissatisfaction of MG-related dysfunction.  
8.1.3. 
EQ-5D-5L 
The EQ-5D-5L is a standardized measure of health status and was developed by the EuroQoL 
Group to provide a simple, generic measure of health status for clinical and economic appraisal.  
The descriptive system comprises 5 dimensions:  
• mobility 
• self-care 
• usual activities 
• pain/discomfort 
• anxiety/depression 
Each dimension has 5 levels: 
• no problem 
• slight problem 
• moderate problem 
• severe problem 
• extreme problem 
The participant will be asked to indicate his/her health state by ticking the (or placing a cross in) 
the box against the most appropriate statement in each of the 5 dimensions. This decision results 
in a 1-digit number expressing the level selected for that dimension. The digits for 5 dimensions 
were combined in a 5-digit number describing the respondent’s health state. A unique health 
state is defined by combining 1 level from each of the 5 dimensions. A total of 3125 possible 
health states could be defined in this way. Each state is referred to in terms of a 5-digit code. For 
example, state 11111 would indicate no problems in any of the 5 dimensions, while state 12345 
would indicate no problem with mobility, slight problems with washing or dressing, moderate 
problems with doing usual activities, severe pain or discomfort, and extreme anxiety or 
depression. 
A VAS is included in the questionnaire. Participants are asked to mark the health status from 0 to 
100 on the day the interview is conducted, with a score of 0 corresponding to “the worst health 
you can imagine” and 100 corresponding to “the best health you can imagine.” 
8.1.4. 
Pharmacodynamics 
Total IgG levels and AChR antibody levels (in AChR-Ab seropositive participants only) will be 
measured using validated methods from blood samples as indicated in Section 1.3. The actual 
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date and time of the blood sample collection will be collected and included in the central 
laboratory data transfer.  
8.2. 
Safety Assessments 
Planned time points for all safety assessments are provided in the SoA (Section 1.3). 
8.2.1. 
Demography 
Demography information will be copied over from antecedent studies ARGX-113-2001 and 
ARGX-113-1705. 
8.2.2. 
Physical Examinations 
A complete physical examination will include, at a minimum, assessments of the participant’s 
general appearance, skin, lymph nodes, musculoskeletal/extremities, abdomen, cardiovascular, 
respiratory, and neurological systems. Investigators should pay special attention to clinical signs 
related to previous serious illnesses. 
8.2.3. 
Vital Signs 
Vital signs (to be taken before blood collection for laboratory tests) will include temperature, 
systolic and diastolic blood pressure, and pulse.  
It is recommended that the method used to measure body temperature at study entry is 
maintained throughout the study. 
Blood pressure and pulse measurements will be assessed in a semi-supine position with a 
completely automated device. Manual techniques will be used only if an automated device is not 
available. 
Blood pressure and pulse measurements should be preceded by at least 5 minutes of rest for the 
participant in a quiet setting without distractions (eg, television, cell phones). 
8.2.4. 
Electrocardiograms 
Single 12-lead ECGs will be obtained predose on dosing days, using an ECG machine. 
8.2.5. 
Medical and Surgical History 
Medical history from the antecedent studies ARGX-113-2001, ARGX-113-1704, and 
ARGX-113-1705 will be used.  
8.2.6. 
Clinical Safety Laboratory Assessments 
See Section 10.2 for the list of clinical laboratory tests to be performed. 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 will be collected and included in the central 
laboratory data transfer. 
The investigator must review the laboratory report, document this review, and record any 
clinically significant changes occurring during the study as an AE. The laboratory reports must 
be filed with the source documents.  
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All routine laboratory safety assessments must be performed by the central laboratory. 
Abnormal laboratory findings associated with the underlying disease are not considered 
clinically significant unless judged by the investigator to be more severe than expected for the 
participant's condition. 
All laboratory tests with values considered clinically significantly abnormal during participation 
in the study should be repeated until the values return to normal or baseline or are no longer 
considered clinically significant by the investigator or medical monitor. 
• If any values do not return to normal/baseline within a period of time judged 
reasonable by the investigator, the etiology should be identified, and the sponsor 
notified. 
• All protocol-required laboratory tests, as defined in Section 10.2, must be conducted 
in accordance with the laboratory manual and the SoA (Section 1.3).  
• If laboratory values from nonprotocol specified laboratory tests performed at the 
institution’s local laboratory require a change in participant management or are 
considered clinically significant by the investigator and an SAE, then it must be 
recorded on the SAE form. 
8.2.6.1. 
Hematology, Clinical Chemistry, Coagulation Panel and Urinalysis 
Clinical laboratory tests will be reviewed for potential clinically significant findings at all time 
points throughout the study. Findings meeting the definition of an AE (see Section 10.4) must be 
recorded on an AE page of the eCRF. See Section 10.4.3 for information on following up of 
clinically significant abnormalities 
Laboratory tests with values considered clinically significantly abnormal during the study that 
meet the definition of an AE will be monitored until the values return to normal or baseline or 
are no longer considered clinically significant by the investigator or medical monitor. 
8.2.6.2. 
SARS-CoV-2 Test 
Nasal and throat mucosal cell samples will be collected according to the laboratory manual at the 
time points to be tested for SARS-CoV-2 as needed. Participants should only be tested if they 
have symptoms of COVID-19 or if they were in contact with someone who tested positive for 
SARS-CoV-2, unless local or site regulations have more stringent testing requirements. See 
Section 10.6. 
8.2.7. 
Pregnancy Testing 
Urine tests for pregnancy will occur for WOCBP at the time points specified in the SoA 
(Section 1.3). Pregnancy testing in WOCBP will be conducted at the end of relevant systemic 
exposure (ie, at the SFU). 
Additional pregnancy testing could be performed as necessary by the investigator or as required 
by local regulations, to establish the absence of pregnancy at any time during the study. 
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8.2.8. 
Immunogenicity 
8.2.8.1. 
ADA Against Efgartigimod 
Blood samples will be collected to assess the serum levels of ADA against efgartigimod as 
indicated in the SoA (Section 1.3). Sampling will be done predose on IMP administration visits. 
The details of sampling, handling, storage, and transportation of the samples will be described in 
the laboratory manual. 
As per regulations, all samples will be analyzed in a 3-tiered approach using validated methods:7  
1. First, all samples will be evaluated in a screening assay (tier 1) and scored as ADA 
positive or negative 
2. Samples that screen positive in tier 1 will be evaluated in the confirmatory ADA assay to 
assess the specificity of the ADA response. The samples will be scored as either 
confirmed positive (ie, positive immunodepletion) or confirmed negative (ie, negative 
immunodepletion). 
3. Samples confirmed to be positive for ADA in tier 2 will be further analyzed in a titration 
assay to characterize the magnitude of the ADA response and a NAb assay to assess the 
ADA for neutralizing activity. 
If no sample was taken, the reason will be recorded. 
8.2.8.2. 
ADA Against rHuPH20 
Blood samples will be collected to assess the plasma levels of ADA against rHuPH20 as 
indicated in the SoA (Section 1.3), including a sample taken at the first visit of the first TP 
(TP1V1) for participants coming from study ARGX-113-1705 and for participants coming from 
study ARGX-113-2001 who received efgartigimod IV. Sampling will be done predose on IMP 
administration visits. The details of sampling, handling, storage, and transportation of the 
samples will be described in the laboratory manual. If no sample was taken, the reason will be 
recorded. 
As per regulations, samples will be analyzed in a 3-tiered approach using validated methods:7  
1. Samples will be analyzed in a screening assay (tier 1), which identifies putative positive 
or negative samples. 
2. Samples that screen positive in tier 1 will be evaluated in the confirmatory ADA assay to 
assess the specificity of the ADA response. The samples will be scored as either 
confirmed positive or negative. 
3. Samples confirmed to be positive for ADA in tier 2 will be further analyzed in a titration 
assay to characterize the magnitude of the ADA response, and a neutralizing antibody 
(NAb) assay to assess the ADA for neutralizing activity. 
Samples taken during the second year will only be analyzed if needed for safety purposes. 
 
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8.2.9. 
Vaccine Antibody Titers and PBMCs 
Additional blood samples (serum/peripheral blood mononuclear cells [PBMCs]) may need to be 
taken for additional/optional/future/vaccination research if the participant consents. If a 
participant consents to this additional sampling, the following samples are to be taken in case of 
vaccination: 
• The baseline serum sample can be taken at any moment before the vaccination is 
administered. This sample does not have to be taken at the baseline visit. 
• The second serum sample is to be taken at least 4 weeks after the vaccine has been 
administered.  
• A third serum sample is to be taken at the first IPnV1 that is at least 4 weeks after the 
vaccine has been given. In case the visits of the second and the third sample coincide, 
then only 1 sample is needed. 
Serum samples only need to be taken when a vaccination is planned (baseline sample) or after a 
vaccination has occurred (second/third sample).  
 
In addition, a whole-blood sample to isolate PBMCs will be collected at study entry and then 
approximately every 3 months throughout the study during a scheduled on-site visit, regardless 
of the vaccines a participant has received. The details of sampling, handling, storage, and 
transportation of the samples will be described in the laboratory manual. 
8.2.10. 
Suicidal Ideation and Behavior Risk Monitoring 
Efgartigimod PH20 SC is being developed for a neurologic indication. Therefore, per US Food 
and Drug Administration (FDA) guidance, suicidal ideation and behavior (SIB) risk monitoring 
is required.8 
Participants being treated with efgartigimod should be monitored appropriately and observed 
closely for SIB or any other unusual changes in behavior, especially at the beginning and end of 
the course of intervention, or at the time of dose changes, either increases or decreases. 
Participants who experience signs of SIB, should undergo a risk assessment. All factors 
contributing to SIB should be evaluated and consideration should be given to discontinuation of 
the study intervention. 
Baseline assessment of SIB and intervention emergent SIB will be monitored by asking the 
following question derived from the 9-item Patient Health Questionnaire (PHQ-9): "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?" 
8.3. 
Adverse Events, Serious Adverse Events, and Other Safety 
Reporting 
The definitions of AEs and SAEs can be found in Section 10.4.  
AEs will be reported by the participant (or, when appropriate, by a caregiver, or surrogate). 
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The investigator and any qualified designees are responsible for detecting, documenting, and 
recording events that meet the definition of an AE or SAE and remain responsible for following 
up AEs that are serious, considered related to the study intervention or study procedures, or that 
caused the participant to discontinue the study intervention (see Section 7). 
An unexpected AE is any adverse drug event, which is not listed in the reference safety 
information in the current IB or is not listed at the specificity or intensity that has been observed 
in the current study. 
Suspected adverse drug reaction means any AE for which there is a reasonable possibility that 
the IMP caused the AE. 
Each AE is to be evaluated for duration, severity (using the Common Terminology Criteria for 
Adverse Events [CTCAE] criteria version 5.0), seriousness, and causal relationship to the IMP or 
study procedures. The action taken with the investigational drug and the outcome of the event 
must also be recorded. 
The method of recording, evaluating, and assessing causality of AEs and SAEs and the 
procedures for completing and transmitting SAE reports are provided in Section 10.4.3 and 
Section 10.4.4. 
8.3.1. 
Time Period and Frequency for Collecting AE and SAE Information 
All AEs and SAEs will be collected from the signing of the ICF until the EoS visit or the SFU 
visit at the time points specified in the SoA (Section 1.3). Ongoing AEs from the antecedent 
studies must also be recorded. 
All SAEs will be recorded and reported to the sponsor or designee immediately and under no 
circumstance should this exceed 24 hours from awareness of the site staff, as indicated in 
Section 10.4. The investigator will submit any updated SAE data to the sponsor within 24 hours 
of the information being available. 
Investigators are not obligated to actively seek information on AEs or SAEs after conclusion of 
the study participation. However, if the investigator learns of any SAE, including a death, at any 
time after a participant has been discharged from the study, and he/she considers the event to be 
reasonably related to the study intervention or study participation, the investigator must promptly 
notify the sponsor. 
8.3.2. 
Method of Detecting AEs and SAEs 
Care will be taken not to introduce bias when detecting AEs and/or SAEs. Open-ended and 
nonleading verbal questioning of the participant is the preferred method to inquire about 
AE occurrences. 
8.3.3. 
Follow-up of AEs and SAEs 
After the initial AE/SAE report, the investigator is required to proactively follow each participant 
at subsequent visits/contacts. All AESIs as defined in Section 8.3.6 will be followed until 
resolution, stabilization, the event is otherwise explained, or the participant is lost to follow-up 
(as defined in Section 7.3). Further information on follow-up procedures is provided in 
Section 10.4.3. 
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8.3.4. 
Regulatory Reporting Requirements for SAEs 
Prompt notification by the investigator to the sponsor of an SAE is essential so that legal 
obligations and ethical responsibilities toward the safety of participants and the safety of a study 
intervention under clinical investigation are met. 
The sponsor has a legal responsibility to notify both the local regulatory authority and other 
regulatory agencies about the safety of a study intervention under clinical investigation. The 
sponsor will comply with country-specific regulatory requirements relating to safety reporting to 
the regulatory authority, IRB/IEC, and investigators. 
An investigator who receives an investigator safety report describing an SAE or other specific 
safety information (eg, summary or listing of SAEs) from the sponsor will review and then file it 
along with the IB and will notify the IRB/IEC, if appropriate according to local requirements. 
The sponsor (or its designee) will be responsible for reporting suspected unexpected serious 
adverse reactions (SUSARs) to the relevant regulatory authorities and the IRB/IEC as per 
applicable regulatory requirements. The sponsor (or its designee) will also be responsible to 
forward SUSAR reports to all investigators involved in the study, who will also be required to 
report these SUSARs to their respective IECs/IRBs, as per their local regulatory requirements. 
8.3.5. 
Pregnancy 
Details of all pregnancies in female participants will be collected from when the participant 
enters the study and until 90 days after the last dose of the study IMP. 
Attempts will be made to obtain details of all pregnancies in female partners of male participants 
that occurred after the start of study intervention and until 90 days after the last dose of IMP. 
Female partners will be asked to sign a relevant ICF. 
If a pregnancy is reported, the investigator will record pregnancy information on the appropriate 
form and submit it to the sponsor within 24 hours of learning of the female participant or female 
partner of male participant (after obtaining the necessary signed ICF from the female partner) 
pregnancy. 
While pregnancy itself is not considered to be an AE or SAE, any pregnancy complication or 
elective termination of a pregnancy for medical reasons will be reported as an AE or SAE. 
Abnormal pregnancy outcomes (eg, spontaneous abortion, fetal death, stillbirth, congenital 
anomalies, ectopic pregnancy) are considered SAEs and will be reported as such. 
The pregnant participant will be followed to determine the outcome of the pregnancy. The 
investigator will collect follow-up information on the participant and the neonate and the 
information will be forwarded to the sponsor. 
If a female partner of a male participant consents, the female partner will be followed to 
determine the outcome of the pregnancy. In this case, the investigator will collect follow-up 
information on the female partner and the neonate and the information will be forwarded to the 
sponsor. 
Any post-study pregnancy-related SAE considered reasonably related to the study intervention 
by the investigator will be reported to the sponsor as described in Section 8.3.4. While the 
investigator is not obligated to actively seek this information in former study participants or 
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pregnant female partners of former male study participants, he/she may learn of an SAE through 
spontaneous reporting. 
Any female participant who becomes pregnant while participating in the study will be 
discontinued from the study intervention and will perform the ET visit (if applicable) and the 
SFU visit, as described in Section 7.2. 
8.3.6. 
Adverse Events of Special Interest 
An AESI is an event of scientific and medical concern specific to the sponsor’s product or 
program (eg, an underlying condition being investigated, a mechanism of action/potential 
immunosuppression). An AESI can be serious or nonserious and related or unrelated to study 
IMP or procedures. Further characterizing information will be collected in the eCRF.  
Efgartigimod treatment induces reductions in the IgG levels and there is a potential risk for 
infections associated with low IgG levels. As such, any infections are considered AESIs in this 
study. Further information to be collected in the eCRF will include: 
• Location of the infection 
• Relationship to the underlying condition, medical history, and concomitant 
medications 
• Reoccurrence of previous infection 
• Previous rescue therapy 
• Any confirmatory procedure, culture, or urgent medical intervention 
8.3.7. 
AEs of Clinical Interest 
8.3.7.1. 
Injection-Related Reactions  
All therapeutic proteins can elicit immune responses, potentially resulting in hypersensitivity or 
allergic reactions such as rash, urticaria, angioedema, serum sickness, and anaphylactoid or 
anaphylactic reactions. As with any SC injection, injection-related reactions can occur during or 
after administration. 
Overall, the frequency of injection-related reactions in clinical studies has been low.  
The efgartigimod IB provides more information on injection-related reactions. 
8.3.7.2. 
Injection-Site Reaction  
An injection-site reaction is any AE developing at the injection site. Localized injection-site 
reactions were observed in studies of efgartigimod with PH20 administered SC. The most 
frequently reported injection-site reaction AEs are Injection site erythema, Injection site pain, 
and Injection site swelling. 
Any injection-site reaction will be reported as an AE (Section 8.3). Certain types of local 
reactions could be photographed and shared with the sponsor for review and assessment.  
As a routine precaution, participants will be trained or observed closely by a trained health-care 
professional for any potential injection-site reaction. 
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Refer to the current IB for more information on injection-site reactions. 
8.4. 
Pharmacokinetics 
Blood samples for PK will be collected from each participant as specified in the SoA (Section 
1.3). Concentrations of efgartigimod will be determined using a validated method. If no sample 
was taken, the reason will be recorded. 
Instructions for the collection and handling of biological samples will be provided by the 
sponsor. The actual date and time (24-hour clock time) of each sample will be recorded. 
At visits during which blood samples for the determination of multiple aspects of efgartigimod 
will be taken, 1 sample of sufficient volume can be used. 
PK sampling will be done predose (within 1 hour prior to the injection) at study entry. 
To characterize anticipated peak concentrations, efgartigimod concentrations will also be 
measured in a subset of at least 12 participants who consent to additional sampling. These 
participants will perform additional on-site visits 2 days after their first and fourth injections in a 
treatment period. These additional visits can only be performed when all of the injections of that 
treatment period are given at the site. This sampling may only be performed during a 
participant’s first and/or second treatment periods. 
8.5. 
Genetics and/or Pharmacogenomics 
Genetics are not evaluated in this study. 
8.6. 
Biomarkers 
See Section 8.1.4 for assessments of total IgG levels and AChR autoantibody levels. 
8.7. 
Immunogenicity Assessments 
See Section 8.2.8 for immunogenicity assessments.  
8.8. 
Medical Resource Utilization and Health Economics 
Medical resource and health economic parameters including ER visits, hospitalizations, and ICU 
admissions will be recorded in the eCRF to allow for the assessment of change in these 
parameters with efgartigimod PH20 SC treatment. Historical data on these parameters for at least 
12 months prior to the start of the study will be collected only for participants rolling over from 
ARGX-113-1705.  
8.8.1. 
 
 
 
 
 
 
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8.8.2. 
 
 
 
 
 
 
 
 
8.9. 
Storage of Blood Samples After the Study 
Any samples remaining after the laboratory analyses defined in the protocol have been 
completed may be stored for up to 15 years after the end of the study for additional medical, 
academic, or scientific research to address any scientific questions related to efgartigimod, FcRn 
biology, or gMG. The samples may be stored in the laboratory or long-term storage designated 
by the sponsor or research partners worldwide. The storage and future use of samples obtained 
during this study is permitted unless local regulations do not allow it or if the participant did not 
consent.  
In addition, blood samples may be used to validate methods to measure efgartigimod, antibodies 
biomarkers, and methods used for vaccination antibody testing and any other additional research 
interests. 
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9. 
STATISTICAL CONSIDERATIONS 
The statistical analysis will be performed by the sponsor’s designated CRO using Statistical 
Analysis Systems (SAS) software (SAS Institute, Cary, NC, United States) version 9.4 or higher, 
and the software package R, if applicable. The standard operating procedures (SOPs) and work 
instructions of the sponsor’s designated CRO will be used as the default methodology if not 
otherwise specified. 
A detailed and comprehensive Statistical Analysis Plan (SAP) will be written and signed-off 
prior to an interim or final analysis database lock. Minor changes to the statistical methods set 
out in this protocol do not require a protocol amendment but will be documented (as changes 
from the protocol) in the SAP and in the clinical study report(s). The below sections contain the 
main general features of the statistical analysis. More details will be provided in the SAP. 
9.1. 
Statistical Hypotheses 
Not applicable to this one-arm, open-label long-term safety study. 
9.2. 
Sample Size Determination 
No sample size calculation is needed in this study. Up to 201 participants may be enrolled from 
the antecedent studies ARGX-113-2001 and ARGX-113-1705. 
Note: “Enrolled” means a participant’s agreement to enter a clinical study following completion 
of the informed consent process and screening. Potential participants who are screened for the 
purpose of determining eligibility for the study, but do not participate in the study, are not 
considered enrolled, unless otherwise specified by the protocol.  
9.3. 
Analysis Sets 
The analysis set defined in Table 6 will be used for all analyses. 
Table 6: 
Analysis Sets 
Analysis Sets 
Description 
Safety analysis set 
All participants who are exposed to IMP in this 
study 
Full analysis set 
All participants who are exposed to IMP in this 
study 
9.4. 
Statistical Analyses 
The SAP will be finalized prior to an interim or final database lock and it will include a more 
technical and detailed description of the statistical analyses described in this section. This section 
is a summary of the planned statistical analyses of the most important endpoints including 
primary and key secondary endpoints. 
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9.4.1. 
General Considerations 
Since all participants will receive the same treatment in this open-label long-term safety study, 
analysis of all endpoints will be essentially descriptive. All endpoints will be summarized with 
descriptive statistics by treatment arm in study ARGX-113-2001 and overall among participants 
from study ARGX-113-2001 and also by AChR-Ab status and overall among all participants 
from both study ARGX-113-2001 and study ARGX-113-1705. 
Summary statistics will be provided for the continuous endpoints (eg, MG-ADL total score, 
levels of total IgG and AChR-Abs, MG-QoL15r score, EQ-5D-5L VAS score, laboratory values, 
vital signs) over time (by cycle and over applicable study visits) in terms of absolute values, 
changes from study baseline and changes from cycle baseline.  
Frequency tables will be generated for all categorical endpoints (ie, AEs, ADA against 
efgartigimod and ADA against rHuPH20, and EQ-5D-5L responses to 5 dimensions by cycle and 
overall). 
9.4.2. 
Primary Endpoint(s) 
Summary statistics will be provided for the continuous endpoints and frequency tables will be 
generated for all categorical endpoints. 
9.4.3. 
Secondary Endpoint(s) 
Summary statistics will be provided for the continuous endpoints and frequency tables will be 
generated for all categorical endpoints.  
9.4.4. 
Exploratory Endpoints 
 
 
 
 
 
 
 
 
 
 
9.5. 
Interim Analysis 
Interim analyses might be performed to support questions for authorities and/or submissions. 
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10. 
SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS 
10.1. 
Appendix 1: Regulatory, Ethical, and Study Oversight 
Considerations 
10.1.1. 
Regulatory and Ethical Considerations 
This study will be conducted in accordance with the protocol and with the following: 
• Consensus ethical principles derived from international guidelines including the 
Declaration of Helsinki and Council for International Organizations of Medical 
Sciences (CIOMS) International Ethical Guidelines 
• Applicable International Council for Harmonisation (ICH) Good Clinical Practice 
(GCP) Guidelines 
• Applicable laws and regulations 
The protocol, protocol amendments, ICF, IB, and other relevant documents (eg, advertisements) 
must be submitted to an Institutional Review Board/Independent Ethics Committee (IRB/IEC) 
by the investigator and reviewed and approved by the IRB/IEC before the study is initiated. 
• Any amendments to the protocol will require IRB/IEC approval before 
implementation of changes made to the study design, except for changes necessary to 
eliminate an immediate hazard to study participants.  
• Protocols and any substantial amendments to the protocol will require health 
authority approval prior to initiation except for changes necessary to eliminate an 
immediate hazard to study participants. 
The investigator will be responsible for the following: 
• Providing written summaries of the status of the study to the IRB/IEC annually or 
more frequently in accordance with the requirements, policies, and procedures 
established by the IRB/IEC 
• Notifying the IRB/IEC of serious adverse events (SAEs) or other significant safety 
findings as required by IRB/IEC procedures 
• Providing oversight of the conduct of the study at the site and adherence to 
requirements of 21 Code of Federal Regulations (CFR), ICH guidelines, the IRB/IEC, 
European regulation 536/2014 for clinical studies, and all other applicable local 
regulations 
10.1.2. 
Financial Disclosure 
The sponsor will fund the study as outlined in the clinical study agreement. 
The sponsor will obtain adequate global/local insurance for the study participants including the 
study participants for the required duration of time. 
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The sponsor maintains an insurance coverage for this study in accordance with the laws and 
regulations of the countries in which the study is performed. Liability and insurance provisions 
for this study are specified in the investigator’s contract. The terms and conditions will apply as 
specified in the policy document. 
Investigators and sub-investigators will provide the sponsor with sufficient accurate financial 
information as requested to allow the sponsor to submit complete and accurate financial 
certification or disclosure statements to the appropriate regulatory authorities. Investigators are 
responsible for providing information on financial interests during the course of the study and for 
1 year after completion of the study. 
10.1.3. 
Informed Consent Process 
Before signing the ICF, the study participants will be instructed not to participate in any other 
clinical study that involves a therapeutic intervention until the completion of the study. 
Any participant that provides informed consent will be assigned a unique participant ID via the 
Interactive Response Technology system. 
The investigator or his/her representative will explain to the participant all of the following: the 
nature of the study, its purpose, the procedures involved, the expected duration, any potential 
discomfort, potential alternative procedure(s) or course(s) of treatment available, and the extent 
of procedures to maintain the confidentiality of the participant’s records. The investigator or 
his/her representative will answer all questions from the participant regarding the study. 
Participants must be informed that their participation is voluntary, that they may withdraw from 
the study at any time, and that withdrawal of consent will not affect their subsequent medical 
treatment or relationship with the treating physician. 
Participants will be required to sign a statement of informed consent after receipt of detailed 
information on the study that meets the requirements of 21 CFR 50, local regulations, ICH 
guidelines, Health Insurance Portability and Accountability Act (HIPAA) requirements, where 
applicable, and the IRB/IEC or study center. 
The ICF will be used to explain the potential risks and benefits of study participation to the 
participant in simple terms before the participant enters the study. 
The medical record must include a statement that written informed consent was obtained before 
the participant was enrolled in the study and the date the written consent was obtained. The 
authorized person obtaining the informed consent must also sign the ICF. 
A separate ICF will be issued in case of pregnancy of a female partner of a male participant. If 
required by local regulations, a separate pregnancy ICF will be issued for female participants 
who become pregnant.  
A separate ICF will be issued to all caregivers. Caregivers must sign the ICF before being trained 
in IMP administration. A copy of the signed and dated caregiver ICF(s) must be provided to the 
caregiver. 
All participant information and ICFs must be available in the local and vernacular languages 
required at the site and include participant information sheets/brochures that outline the study 
procedures. All ICF(s) must be signed and dated by the participant. 
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Participants must reconsent to the most current version of the ICF(s) during their participation in 
the study. 
The investigator is responsible for ensuring that informed consent is obtained from each 
participant and for obtaining the appropriate signatures and dates on the ICF prior to the 
performance of any protocol procedures.  
A copy of the signed and dated ICF(s) must be provided to the participant. 
10.1.4. 
Data Protection 
Participants will be assigned a unique identifier by the sponsor. Any participant records or 
datasets that are transferred to the sponsor will contain the identifier only; participant names or 
any information which would make the participant identifiable will not be transferred. 
The participant must be informed that his/her personal study-related data will be used by the 
sponsor in accordance with local data protection law. The level of disclosure must also be 
explained to the participant who will be required to give consent for their data to be used as 
described in the informed consent.  
The participant must be informed that his/her medical records may be examined by Clinical 
Quality Assurance auditors or other authorized personnel appointed by the sponsor, by 
appropriate IRB/IEC members, and by inspectors from regulatory authorities. 
10.1.5. 
Committees Structure 
10.1.5.1. Data Safety Monitoring Board 
Participant safety will be monitored by an independent DSMB, which includes safety signal 
detection at any time during the study. 
The DSMB will consist of an independent group of clinical experts who are not involved in the 
study management. The objective of the DSMB will be to review and evaluate all available 
safety data. The planning and frequency of the meetings will be detailed in the DSMB charter. 
Additionally, ad hoc meetings can be requested at any time during the study by the sponsor or 
the DSMB.  
The DSMB will advise the sponsor regarding continuation, modification, temporary 
discontinuation, or termination of the study after every meeting. 
The composition, objectives, role, and responsibilities of the DSMB will be described in the 
DSMB charter, which will be agreed to by the DSMB members and the sponsor. The DSMB 
charter will also define and document the content of safety summaries and general procedures, 
including communications. 
10.1.6. 
Dissemination of Clinical Study Data 
The sponsor or designee and auditor may access participant records for the purpose of 
monitoring this study, 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 
participant’s chart and eCRF records. Such information must be kept confidential in locked 
facilities that allow for this. The investigator will prepare and maintain adequate and accurate 
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source documents to record all observations and other pertinent data for each participant 
screened for the study. 
The investigator is responsible for maintaining source documents. These will be made available 
for verification by the sponsor’s designated contract research organization (CRO) monitor at 
each monitoring visit. The investigator must submit an eCRF for each participant, regardless of 
duration of participation or administration of IMP (ie, an eCRF has to be submitted for screen 
failures as well). All supportive documentation submitted with the eCRF, such as laboratory or 
hospital records, should be clearly identified with the study and participant number. Any 
personal information, including participant name, should be removed or rendered illegible to 
preserve data privacy. 
10.1.7. 
Data Quality Assurance 
All participant data relating to the study will be recorded in the eCRF unless transmitted to the 
sponsor or designee electronically (eg, laboratory data). The investigator is responsible for 
verifying that data entries are accurate and correct by electronically signing the eCRF. 
The investigator must maintain accurate documentation (source data) that supports the 
information entered in the eCRF if and where applicable. No source data verification will be 
performed on race and ethnicity only if requested per local regulations. 
Guidance on completion of eCRFs will be provided in the CRF completion guidelines by the 
designated CRO.  
The investigator must permit study-related monitoring, audits, IRB/IEC review, and regulatory 
agency inspections and provide direct access to source data documents. 
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. 
The sponsor or designee is responsible for the data management of this study, including quality 
checking of the data. 
The sponsor assumes accountability for actions delegated to other individuals (eg, CROs). 
Study monitors will perform ongoing source data verification to confirm that data entered into 
the eCRF by authorized site personnel are accurate, complete, and verifiable from source 
documents; that the safety and rights of participants are being protected; and that the study is 
being conducted in accordance with the currently approved protocol and any other study 
agreements, ICH GCP, and all applicable regulatory requirements. 
10.1.7.1. Data Handling and Record Keeping 
It is the investigator’s responsibility to maintain essential study documents (records and 
documents pertaining to the conduct of this study and the distribution of IMP, including 
regulatory documents, eCRFs, signed participant 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 study site 
should plan on retaining such documents for approximately 25 years after study completion. The 
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study 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 the IMP. 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 study is being 
conducted. Participant identification codes (participant names and corresponding study numbers) 
will be retained for this same period of time. These documents may be transferred to another 
responsible party, acceptable to the 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 study documents. The investigator must 
contact the sponsor prior to disposing of any study records. 
No records may be destroyed during the retention period without the written approval of the 
sponsor. No records may be transferred to another location or party without written notification 
to the sponsor. 
For studies conducted outside the US under an US investigational new drug (IND), the principal 
investigator must comply with US Food and Drug Administration IND regulations and with 
those of the relevant national and local health authorities. 
10.1.7.2. Quality Assurance Audit 
Study processes, study sites (including, but not limited to site visits, central laboratories, 
vendors), the study database, and study documentation may be subject to quality assurance audit 
during the course of the study 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. Such audits/inspections can occur at any time during or after completion of the study. 
10.1.7.3. Quality Control 
Quality control will be applied to each stage of study-related activities. 
The following steps will be taken to ensure the accuracy, consistency, completeness, and 
reliability of the data: 
• Investigator meetings 
• Central laboratories for clinical laboratory parameters 
• Site initiation visit 
• Routine site monitoring 
• Ongoing site communication and training 
• Ongoing oversight by sponsor’s designated CRO monitors of safety parameters and 
adherence to selection criteria 
• Data management quality control checks 
• Continuous data acquisition and cleaning 
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• Quality control check of the clinical study report (CSR) 
• To avoid interobserver variability, every effort should be made to ensure that the 
same individual who made the initial baseline determinations completes all efficacy 
and safety evaluations 
In addition, periodic audits can be performed as specified in Section 10.1.7.2. 
When audits or inspections are conducted, access must be authorized for all study-related 
documents including medical history and concomitant medication documentation to authorized 
sponsor’s representatives and regulatory authorities. 
10.1.8. 
Source Documents 
Source documents provide evidence for the existence of the participant and substantiate the 
integrity of the data collected. Source documents are filed at the investigator’s site. The 
investigator/institution should maintain a record of the location(s) of their respective essential 
documents, including source documents. 
Data entered in the eCRF that are transcribed from source documents must be consistent with the 
source documents or the discrepancies must be explained. The investigator may need to request 
previous medical records or transfer records, depending on the study. Also, current medical 
records must be available. 
The definition of what constitutes source data can be found in the investigator source data 
agreement. 
The investigator must maintain accurate documentation (source data) that supports the 
information entered in the eCRF. 
Study monitors will perform ongoing source data verification to confirm that data entered into 
the CRF by authorized site personnel are accurate, complete, and verifiable from source 
documents; that the safety and rights of participants are being protected; and that the study is 
being conducted in accordance with the currently approved protocol and any other study 
agreements, ICH GCP, and all applicable regulatory requirements. 
10.1.9. 
Study and Site Start and Closure 
First Act of Recruitment 
The study start date is the date on which the clinical study will be open for recruitment of 
participants. 
The first act of recruitment is the first site open and will be the study start date. 
Study/Site Termination 
The sponsor or designee reserves the right to close the study site or terminate the study at any 
time for any reason at the sole discretion of the sponsor. Study sites will be closed upon study 
completion. A study site is considered closed when all required documents and study supplies 
have been collected and a study-site closure visit has been performed. 
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The investigator may initiate study-site closure at any time, provided there is reasonable cause 
and sufficient notice is given in advance of the intended termination. 
Reasons for the early closure of a study site by the sponsor or investigator may include but are 
not limited to: 
For study termination: 
• Discontinuation of further study intervention development 
• An unexpected negative change to the benefit-risk profile of the IMP  
• Recommendation of termination by the DSMB  
• A necessary adjustment to the maximum insured sum for the study that is not possible  
• Regulatory agency and/or IRB/IEC approvals withdrawn 
For site termination: 
• Failure of the investigator to comply with the protocol, the requirements of the 
IRB/IEC or local health authorities, the sponsor's procedures, or GCP guidelines 
• Inadequate or no recruitment (evaluated after a reasonable amount of time) of 
participants by the investigator 
• Total number of participants included earlier than expected 
If the study is prematurely terminated or suspended, the sponsor shall promptly inform the 
investigators, the IECs/IRBs, the regulatory authorities, and any contract research organization(s) 
used in the study of the reason for termination or suspension, as specified by the applicable 
regulatory requirements. The investigator shall promptly inform the participant and should assure 
appropriate participant therapy and/or follow-up. 
10.1.10. 
Publication Policy 
All information regarding ARGX-113 supplied by the sponsor to the investigator and all data 
generated as a result of this study are considered confidential and remain the sole property of the 
sponsor. The results of the study will be reported in a CSR. The CSR will be written in 
accordance with the ICH E3 guideline and will be submitted in accordance with local 
regulations. 
Any manuscript, abstract, other publication, presentation of the results, or information arising in 
connection with the study must be prepared with the sponsor and must be submitted to the 
sponsor for review and comment prior to submission for publication or presentation. Study 
participant identifiers will not be used in the publication of results. 
The sponsor will comply with the requirements for publication of study results. In accordance 
with standard editorial and ethical practice, the sponsor will generally support publication of 
multicenter studies only in their entirety and not as individual site data. In this case, a 
coordinating investigator will be designated by mutual agreement. 
Authorship will be determined by mutual agreement and in line with International Committee of 
Medical Journal Editors authorship requirements. 
 
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10.2. 
Appendix 2: Clinical Laboratory Tests 
The tests detailed in Table 7 will be performed by the central laboratory. 
Protocol-specific requirements for inclusion or exclusion of participants are detailed in Section 5 
of the protocol. 
Additional tests may be performed at any time during the study as determined necessary by the 
investigator or required by local regulations. 
Investigators must document their review of each laboratory safety report.  
Table 7: 
Protocol-Required Safety Laboratory Tests 
Laboratory Test 
Parameter 
Hematology 
RBC count 
platelet count 
hemoglobin 
hematocrit 
RBC indices: 
MCV 
% reticulocytes 
WBC count with differentiala: 
basophils  
eosinophils 
lymphocytes 
monocytes 
neutrophils 
Clinical chemistry 
BUN 
potassium 
AST/SGOT 
albumin 
creatinine  
sodium 
ALT/SGPT 
CRP 
glucose 
calcium 
ALPb 
Bilirubin, total 
and direct 
HbA1c 
 GGT 
 HDL 
 LDL (measured) 
LDH 
triglycerides 
total cholesterol 
creatinine 
clearance  
Coagulation panel 
aPTT 
PT 
INR 
 
Routine urinalysis 
Specific gravity 
pH, glucose, protein, blood, ketones, bilirubin, nitrite, leukocyte esterase by 
dipstick 
Microscopic examination (if blood or protein is abnormal) 
Pregnancy testing 
Urine hCG pregnancy testc (as needed for women of childbearing potential, 
defined in Section 10.5) 
Unscheduled tests 
SARS-CoV-2 
ALP=alkaline phosphatase; ALT/SGPT=alanine aminotransferase; aPTT=activated partial thromboplastin time; 
AST/SGOT=aspartate aminotransferase; BUN=blood urea nitrogen; CRP=C-reactive protein; GGT=γ Glutamyl 
transferase; HbA1c=glycosylated hemoglobin; hCG=human chorionic gonadotropin; HDL=high density lipoprotein; 
INR=international normalized ratio; LDH=lactate dehydrogenase; LDL=low density lipoprotein; MCV=mean 
corpuscular volume; PT=prothrombin time; RBC=red blood cell; SGOT=serum glutamic-oxaloacetic transaminase; 
SGPT=serum glutamic pyruvic transaminase; WBC=white blood cell 
Note: All samples for safety laboratory tests will be taken with the participant in the fasted state (8 hours). 
a These will be measured in percentage and absolute numbers. 
b Consider fractioning for elevated alkaline phosphatase levels. 
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c Local urine testing will be standard for the protocol unless serum testing is required by local regulation or 
IRB/IEC. 
 
10.3. 
Appendix 3: Total Blood Volume Collected From Each Participant 
The maximum amount of blood collected from each participant is 1493.4 mL. Repeat or 
unscheduled samples may be taken for safety reasons or technical issues with samples. 
 
 
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10.5. 
Appendix 5: Contraceptive and Barrier Guidance 
10.5.1. 
Definitions 
Woman of Childbearing Potential (WOCBP) 
A woman is considered to be of childbearing potential unless she is either: 
• 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 FSH measurement of >40 IU/L is 
accepted as proof of a postmenopausal state for women on hormone replacement 
therapy. 
• Surgically sterilized: Women who have had a documented permanent sterilization 
procedure (ie, hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) 
10.5.2. 
Contraception Guidance 
10.5.2.1. Female Contraception for Women of Childbearing Potential 
WOCBP must use a highly effective or acceptable contraception method, which should be 
maintained at minimum until 90 days after the last dose of IMP. 
Highly effective methods of contraception are: 
1. Combined (estrogen and progestogen-containing) hormonal contraception associated 
with inhibition of ovulation 
a. Oral 
b. Intravaginal 
c. Transdermal 
2. Progestogen-only hormonal contraception associated with the inhibition of ovulation 
a. Oral 
b. Injectable 
c. Implantable 
3. Intrauterine device (IUD) 
4. Intrauterine hormone-releasing system (IUS) 
5. Bilateral tubal occlusion 
6. Vasectomized partner 
7. Sexual abstinence 
• Sexual abstinence is considered a highly effective method only if defined as 
refraining from heterosexual intercourse during the entire period of risk associated 
with the study intervention. The reliability of sexual abstinence needs to be evaluated 
in relation to the duration of the study and the preferred and usual lifestyle of the 
participant. 
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Acceptable methods of contraception are: 
1. Progestogen-only 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 
10.5.2.2. Male Contraception 
No male contraception is required. 
 
 
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10.6. 
Appendix 6: Possible Adaptations to Study Protocol During 
COVID-19 Pandemic 
During the COVID-19 pandemic, study sites and participants are facing unprecedented 
challenges. As a result of this crisis, the sponsor has considered changes that are necessary to 
protect the safety of the participants and the site staff, while still evaluating the long-term safety 
and tolerability of efgartigimod PH20 SC. All sites and participants will follow local regulations 
and guidance regarding preventing the spread of COVID-19.  
The risk assessment, risk mitigation plan, and changes that may occur in response to an increase 
in COVID-19 cases is described in the following sections. 
10.6.1. 
COVID-19 Risk Assessment for Participant Safety 
Efgartigimod administration results in the reduction of all immunoglobulin G (IgG) subtypes, 
potentially hindering immune response and increasing the risk of all infections, including 
COVID-19. However, efgartigimod does not affect the levels of other immunoglobulin subtypes, 
such as IgA and IgM. Also, previous studies have shown that the maximum mean reduction of 
total IgG ranges from 60% to 70% and total IgG levels return to baseline within a few weeks of 
stopping efgartigimod treatment. Furthermore, other elements of the immune system are not 
impacted by efgartigimod treatment. The IV formulation of efgartigimod has been administered 
to over 250 participants, including healthy volunteers and patients with generalized myasthenia 
gravis (gMG), immune thrombocytopenia, and pemphigus, with no infection-related safety 
concerns identified. The efgartigimod PH20 SC doses used in study ARGX-113-2002 have been 
administered to healthy volunteers and patients with chronic inflammatory demyelinating 
polyneuropathy, with no infection-related safety concerns identified. Therefore, despite the 
immunomodulating properties of efgartigimod, efgartigimod treatment is not expected to 
increase the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or 
developing COVID-19 in participants. 
10.6.2. 
COVID-19 Risk Mitigation 
During the entire study, the sites will implement all recommendations issued by the local 
government regarding minimizing the spread of COVID-19 (eg, social distancing, disinfection, 
hygiene, face mask requirements, and use of personal protection equipment [PPE] by site staff), 
including specific guidelines related to clinical research performed in clinical research centers. 
All participants with clinically significant uncontrolled infections, malignancies, or recent 
surgeries are excluded (see Section 5.2). If at any point a participant tests positive for 
SARS-CoV-2, the administration of efgartigimod PH20 SC will be temporarily discontinued 
until the participant’s symptoms have resolved and they no longer test positive for SARS-CoV-2. 
Furthermore, administration of efgartigimod to a participant will be interrupted if a clinically 
significant infection occurs. Infections are also considered an AESI subject to structured safety 
reporting and a detailed questionnaire, so a participant contracting COVID-19 would be recorded 
as an AESI.  
Home administration by a participant or caregiver is permitted for many of the TP visits in the 
study and IP visits are permitted to alternate between on-site visits and phone visits. Thus, the 
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number of necessary on-site visits is minimal, reducing the risk to participants and site staff of 
contracting COVID-19.  
10.6.3. 
Possible Changes in Study Design Due to the COVID-19 Pandemic 
10.6.3.1. Implementation of This Appendix 
Implementation for all sites includes social distancing where possible, PPE, and a telephone call 
before each study visit to check for COVID-19 symptoms. The adaptations to the visits and 
procedures described are acceptable alternatives to the main protocol procedures only under 
exceptional circumstances and after approval of the sponsor and/or CRO. Approval will be 
granted based on the possibility of participants going to the site and per local and/or site 
regulations. 
This appendix is intended for sites in areas where COVID-19 has affected the workload of study 
sites, severe movement restrictions have been imposed, or where there is a risk to participants or 
site staff when attending visits at the site. The duration of these changes will be agreed upon 
between the site and the sponsor/CRO and can be extended based on local epidemic status. 
10.6.3.2. Testing for COVID-19 
Testing for COVID-19 beyond what is mandated by relevant local authorities is not required 
during the study. However, it is recommended that participants who develop COVID-19 
symptoms during the study or have contact with someone who tested positive for SARS-CoV-2 
be tested. 
During the pandemic, the site staff should contact participants prior to each visit to inquire about 
COVID-19 symptoms (ie, fever, cough, sneezing, loss of taste/smell, difficulties breathing/chest 
tightness) and exposure to determine if it is safe for the participant to proceed with the visit as 
planned. 
At study entry, if the participant cannot come to the site due to COVID-19 infection or travel 
restrictions, the ICF can be signed remotely. If a participant is infected with COVID-19, they 
cannot be (re)treated until they no longer test positive for SARS-CoV-2 and no longer have 
symptoms of a COVID-19 infection. These participants can still enter the ARGX-113-2002 
study by entering an IP. 
10.6.3.3. Study Protocol Changes 
If the COVID-19 pandemic results in participants being unable to visit the site, a home nurse can 
perform visits that are mandatory to be performed at the site (Section 1.3). A home nurse will be 
a qualified person from either the study site staff or a home health care vendor if allowed per 
local requirement. The use of a home nurse will depend on regional availability. If a home nurse 
is being used, the visits can take place at the participant’s home or an alternative location agreed 
upon by both parties. Additionally, all IP and TP visits, except TPnV1 and the first 2 visits of the 
IP that occur before the first TP (IP0), can be performed by phone if necessary. In the first year, 
the first visit of an IP after a TP, called IPnV1, must occur on-site. The second IP visit (IPnV2) 
will also be on-site. Subsequent visits may alternate between telephone and on-site visits. During 
an IP, consecutive telephone visits are not allowed, except in exceptional circumstances caused 
by the COVID-19 pandemic and after approval by the sponsor and/or the CRO. 
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The COVID-19 pandemic may lead to restrictions that reduce the ability of study monitors to 
travel to the sites to verify source data, protection of participant safety and rights, and 
compliance to the protocol, other study agreements, ICH GCP guidelines, and applicable 
regulatory requirements. In these cases, remote monitoring will be performed where possible and 
permitted by local regulations. Any remote access will exclusively use a secure electronic system 
that is compliant with local regulations. Participants will be informed of this possibility before 
giving consent. 
10.6.3.4. Critical Parameters to Be Collected During the Study 
All assessments should be performed as indicated in the SoA (Section 1.3) if possible. In the 
event that some assessments cannot be performed due to the COVID-19 pandemic, the following 
critical parameters must be collected: all AE reporting, injection site reactions, suicide ideation 
and behavior monitoring, IMP administration, who performed the administration, training and 
competency to perform self-administration, MG-ADL total score, quality of life assessments 
(first year only), 
 
 
 
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10.7. 
Appendix 7: Abbreviations and Definitions 
10.7.1. 
Definitions 
Baseline: the data collected prior to the first dose of efgartigimod in this study 
Caregiver: a person of legal age from the participant’s social network (eg, family, relatives, 
friends) introduced by the participant. After receiving the necessary training, the caregiver can 
administer the SC injections to the participant 
Cycle: a period that includes both a TP and the corresponding IP and ends immediately prior to 
the first dose of the next TP 
Cycle baseline: the data collected prior to the start of each cycle 
Enrolled: A participant’s agreement to enter a clinical study following completion of the 
informed consent process and screening. Potential participants who are screened for the purpose 
of determining eligibility for the study, but do not participate in the study, are not considered 
enrolled, unless otherwise specified by the protocol. 
10.7.2. 
Abbreviations 
AChE 
acetylcholinesterase 
AChR 
acetylcholine receptor 
AChR-Ab 
anti-acetylcholine receptor antibody 
ADA 
antidrug antibodies 
AE 
adverse event 
AESI 
adverse event of special interest 
CFR 
Code of Federal Regulations 
CIOMS 
Council for International Organizations of Medical Sciences 
CONSORT 
Consolidated Standards of Reporting Trials 
CRO 
contract research organization 
CSR 
clinical study report 
CTCAE 
Common Terminology Criteria for Adverse Events 
DSMB 
Data and Safety Monitoring Board 
ECG 
electrocardiogram 
eCRF 
electronic case report form 
EoS 
end of study 
ER 
emergency room 
ET 
end of treatment 
FcRn 
neonatal Fc receptor 
FSH 
follicle-stimulating hormone 
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gMG 
generalized myasthenia gravis 
GCP 
Good Clinical Practice 
hCG 
human chorionic gonadotropin 
HIPAA 
Health Insurance Portability and Accountability Act 
IB 
investigator’s brochure 
ICF 
informed consent form 
ICH 
International Council for Harmonisation of Technical Requirements for 
Registration of Pharmaceuticals for Human Use 
ICU 
intensive care unit 
IEC 
Independent Ethics Committee 
Ig 
immunoglobulin 
IgG 
immunoglobulin G 
IMP 
investigational medicinal product 
IND 
investigational new drug 
IP 
intertreatment period 
IPnVm 
intertreatment period (period number) visit (visit number) 
IRB 
Institutional Review Board 
IV 
intravenous(ly) 
 
 
MG-ADL 
Myasthenia Gravis Activities of Daily Living 
MG-QoL15r 
Myasthenia Gravis Quality of Life 15 item scale revised 
NAb 
neutralizing antibody 
NMJ 
neuromuscular junction 
NSID 
nonsteroidal immunosuppressant 
PBMC 
peripheral blood mononuclear cells 
PD 
pharmacodynamics 
PH20 
recombinant human hyaluronidase PH20 (rHuPH20) 
PHQ-9 
9-item Patient Health Questionnaire 
PK 
pharmacokinetics 
PLEX 
plasma exchange 
PPE 
personal protective equipment 
PT 
prothrombin time 
q2w 
every 2 weeks (biweekly) 
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q7d 
every 7 days 
QMG 
Quantitative Myasthenia Gravis 
QoL 
quality of life 
QRS 
duration of ventricular depolarization 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SARS-CoV-2 
severe acute respiratory syndrome coronavirus 2 
SAS 
safety analysis set 
SC 
subcutaneous(ly) 
SFU 
safety follow-up 
SIB 
suicidal ideation and behavior 
SoA 
schedule of activities 
SOP 
standard operating procedure 
SUSAR 
suspected unexpected serious adverse reactions 
TEAE 
treatment-emergent adverse events 
 
 
TP 
treatment period 
TPnVm 
treatment period (number) visit (number) 
UNS 
unscheduled  
VAS 
visual analog scale 
WOCBP 
woman of childbearing potential 
10.8. 
Appendix 8: Germany-Specific Requirements 
10.8.1. 
Overview 
To align with the upcoming Regulation (EU) No. 536/2014, this protocol amendment supersedes 
prior country-specific amendments. Therefore, all changes from the Germany-specific v2.2 
protocol were incorporated with the below exceptions that were first implemented in the 
Germany-specific v1.5 protocol. The following changes were not included in the global protocol 
v3.0 because they were only applicable to the starting phase of the study: 
• An obligatory treatment-free visit at the start of the study to test for SARS-CoV-2 
before IMP 
• Exclusion criterion for being infected with SARS-CoV-2 
• Exclusion criteria to comply with Section 7 (3), No. 4 GCP Regulation and Section 
40 Para. 1 S.3 No.4 AMG (German Drug Law), respectively 
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10.8.2. 
Germany-Specific Document History 
Germany-Specific  
DOCUMENT HISTORY 
Document 
Date 
Protocol version 1.1-Germany 
19 May 2021 
Protocol version 1.2-Germany 
02 Jun 2021 
Protocol version 1.3-Germany 
10 Jun 2021 
Protocol version 1.4-Germany 
07 Jul 2021 
Protocol version 1.5-Germany 
02 Aug 2021 
Protocol version 2.1-Germany 
22 Sep 2021 
Protocol version 2.2-Germany 
07 Jun 2022 
Protocol version 3.0 (global, to supersede 
Germany v2.2) 
02 Feb 2023 
10.8.3. 
Summary of Changes Between Protocol Version 2.1-GER and Protocol Version 
2.2-GER 
 
Overall Rationale for the Changes in Protocol Version 2.2-Germany 
The changes implemented in the protocol were include in 3 protocol clarification letters (dated 
05 Oct 2021, 01 Dec 2021, and 01 Feb 2022) and have been updated into an amendment at the 
request of the competent authorities. 
The major changes from protocol version 2.1 compared with protocol version 2.2 are 
summarized in the following table. A double strikethrough indicates text that was removed and 
bold text indicates text that was added. Minor editorial changes, including the correction of 
typographical errors and formatting inconsistencies, are not summarized.  
 
Section and Name 
Description of Change 
Brief Rationale 
Protocol Signature 
Page 
, MD, PhD is now the 
sponsor signatory for this protocol. 
Effective 01 Apr 2022, Dr. 
 
 became the sponsor’s chief 
medical officer. 
10.1.3 Informed 
Consent Process 
Prior to signing the ICF, the study 
participants will be instructed not to 
participate in any other clinical study that 
involves an therapeutic intervention or 
collection of data until the completion of 
the study. 
Clarified that participants enrolled 
in another study not involving a 
therapeutic intervention should not 
be excluded or discontinued 
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8.2.9.2 ADA 
Against rHuPH20 
 
Other sections 
impacted by the 
added text: 
1.3 Schedule of 
Activities, footnote 
r 
Blood samples will be collected to assess 
the plasma levels of ADA against 
rHuPH20 … for participants coming 
from study ARGX-113-1705 and for 
participants coming from study 
ARGX-113-2001 who received 
efgartigimod IV. 
Corrected the omission of ADA 
sampling for participants coming 
from study ARGX-113-2001 who 
received efgartigimod IV 
8.2.10 Vaccine 
Antibody Titers and 
PBMCs 
 
Other sections 
impacted by the 
edited text: 
1.3 Schedule of 
Activities, footnote 
q 
If a participant that consents to this 
additional sampling receives a 
vaccination during the study, a baseline 
serum sample prior to the vaccination 
will be taken and a serum sample will be 
taken at least 4 weeks after the vaccine 
was administered. The closest visit that is 
at least 4 weeks after the vaccine was 
administered may be used. If this visit 
does not coincide with IPnV1, then 
another sample will also be taken at this 
visit, the following samples are to be 
taken in case of vaccination: 
• 
The baseline serum sample can 
be taken at any moment before 
the vaccination is 
administered. This sample does 
not have to be taken at the 
baseline visit. 
• 
The second serum sample is to 
be taken at least 4 weeks after 
the vaccine has been 
administered.  
• 
A third serum sample is to be 
taken at the first IPnV1 that is 
at least 4 weeks after the 
vaccine has been given. In case 
the visits of the second and the 
third sample coincide, then 
only one sample is needed. 
Clarified the time points when 
additional blood samples may be 
needed for 
additional/optional/future/ 
vaccination research if the 
participant receives a vaccination 
during the study 
4.1 Overall Design 
 
Other sections 
impacted by the 
added text: 
1.3 Schedule of 
Activities, footnote 
d 
If a participant is not in need of 
retreatment, the next visit will be an IP 
visit. In this case, IP visits will be 
performed every 21 days and may 
alternate between on-site visits and 
phone visits. However, the first 2 visits 
of an IP must be on-site, and 2 
Clarified that the first 2 visits of an 
IP, both before the first TP and after 
a TP, must be at the site 
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consecutive phone visits are not 
allowed. 
8.2.9.2 ADA 
Against rHuPH20  
 
Other sections 
impacted by the 
edited text: 
1.3 Schedule of 
Activities, footnote 
r 
Blood samples will be collected to assess 
the plasma levels of ADA against 
rHuPH20 as indicated in the SoA 
(Section 1.3), including a sample taken at 
study entry the first visit of the first TP 
(TP1V1) … 
Clarified that the baseline sample 
for ADA against rHuPH20 will not 
be obtained until the first visit of the 
first TP (TP1V1) 
4.1 Overall Design 
 
Other sections 
impacted by the 
added text: 
 
1.3 Schedule of 
Activities, footnote 
w 
 
Once participants or their caregivers are 
competent to perform IMP 
administration and they have performed 
at least 1 administration at the site under 
the supervision of the site staff, including 
during study ARGX 113 2001, 
participants will be allowed to administer 
efgartigimod PH20 SC at home or at the 
site. However, the first administration of 
a TP must always be done at the site. 
Participants and their caregivers must 
complete the training to the 
satisfaction of the site staff (a 
minimum of 1 visit) before (self-) 
administering efgartigimod PH20 SC 
under the supervision of the site staff. 
Therefore, a minimum of 2 visits is 
required for a participant or caregiver 
to be considered competent to 
administer efgartigimod PH20 SC at 
home. Participants and caregivers who 
were considered competent to (self-) 
administer and successfully (self-) 
administered at least once under 
supervision of the site staff in the 
antecedent study, ARGX-113-2001, 
may (self-) administer efgartigimod 
PH20 SC at home as of the second visit 
of the first TP. All participants must 
come to the site for the first 
administration of a TP, even if the 
participant or caregiver administers. 
Subsequent administrations at visits 2, 3, 
and 4 of that TP can be performed at 
home. 
Clarified that a minimum of 2 visits 
is required for a participant or 
caregiver to be considered 
competent to administer 
efgartigimod PH20 SC at home 
10.2.1 Specialty 
Laboratory Tests 
At the visits listed in the SoA (Section 
1.3.), blood will be sampled under fasting 
conditions for specialty laboratory 
Removed PCSK9 assessment from 
specialty laboratory tests 
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parameters that may include but not be 
limited to apolipoprotein B (apoB), 
lipoprotein A, fibrinogen, von 
Willebrand factor, and d-dimer, 
proprotein convertase subtilisin/kexin 
type 9 serine protease (PCSK9). 
5.1 Inclusion 
Criteria  
2a…Were discontinued from study 
treatment for reasons other than 
pregnancy or an S(AE) a life-
threatening SAE.  
Clarified that a participant is 
eligible if they were discontinued 
due to an SAE that was not life-
threatening 
10.2 Appendix 2: 
Clinical Laboratory 
Tests, Table 3 
Content in Table 3 of the Clinical Study 
Protocol ARGX-113-2002 v1.5-GER (02 
Aug 2021) was restored. 
Corrected the unintentional removal 
and insertion of laboratory 
parameters in Table 3 that occurred 
due to a reformatting issue in CTP 
v2.0 (10 May 2021) 
 
10.8.4. 
Summary of Changes Between Protocol Version 1.5-GER and Protocol Version 
2.1-GER  
 
Overall Rationale for the Changes in Protocol Version 2.1-Germany 
The overall rationale for this amendment includes adding additional optional pharmacokinetic 
samples from a subset of participants to better evaluate the pharmacokinetics of the 
investigational medicinal product (IMP), as requested by competent authorities. Additionally, 
more clinical chemistry laboratory assessments have been added to evaluate the effect of the IMP 
on lipid panels. 
The major changes from Protocol Version 1.5 compared with Protocol Version 2.1 are 
summarized in the following table. A double strikethrough indicates text that was removed and 
bolded text indicates text that was added. Minor editorial changes, including the correction of 
typographical errors and formatting inconsistencies, are not summarized. 
 
Section and Name 
Description of Change 
Brief Rationale 
Title Page 
Industriepark Zwijnaarde 7 
B 9052 Zwijnaarde (Ghent) 
Belgium 
Corrected argenx address 
Added name and affiliation of 
principal/coordinating investigator 
Added Investigator’s Agreement and signature 
Integrated investigator 
information into protocol 
Emergency Contact 
Information 
Added the Emergency Contact Information 
section with information about SAE reporting 
Updated email address 
and fax number for 
reporting SAEs 
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Section 1.1 Synopsis, 
Objectives and 
Endpoints 
Section 3 Objectives 
and Endpoints 
Incidence and severity of adverse events (AEs), 
incidence of serious adverse events (SAEs), 
and AEs of special interest (AESIs), and 
changes in laboratory test results, physical 
examination results, vital signs, and 
electrocardiogram results 
Edited endpoints for 
clarity 
 
 
 
Added secondary objective and endpoint 
Objective: 
To evaluate the PK of efgartigimod PH20 
SC 
Endpoint: 
Efgartigimod serum concentrations 
Added an objective and 
endpoint to assess the PK 
with the additional 
optional PK assessments. 
Section 1.1 Synopsis, 
Overall Design 
Section 4.1 Overall 
Design  
Section 10.8.1 
Definitions 
A caregiver is a person of legal age from the 
participant’s social network (eg, family, 
relatives, friends) introduced by the 
participant. After receiving the necessary 
training, the caregiver can administer the 
SC injections to the participant. 
Added the definition of 
the caregiver 
Section 4.1 Overall 
Design 
The total study duration is 2 years from the 
participant’s first visit in this study: 
• 
3-week treatment periods (TPs), 
repeated as needed based on the 
clinical effect, with a maximum of 14 
TPs 
Added information 
contained in the synopsis 
to the body of the protocol 
Section 1.1 Synopsis 
Section 9.2 Sample Size 
Determination 
“Enrolled” means a participant’s, or their 
legally acceptable representative’s, agreement 
to participate in a clinical study following 
completion of the informed consent process 
and screening. 
Removed references to the 
participant’s legally 
authorized or legally 
acceptable representative 
that are not applicable to 
this study. 
Section 8.3 Adverse 
Events, Serious 
Adverse Events, and 
Other Safety Reporting 
AEs will be reported by the participant (or, 
when appropriate, by a caregiver, or surrogate, 
or the participant’s legally authorized 
representative). 
Section 1.3 Schedule of 
Activities 
Added 2 visits, PK1 and PK2, to take place 
2 days after the first and fourth dose in a 
treatment period, respectively. These visits 
have “Pharmacokinetics” activity row checked. 
Added footnote c 
These are optional visits to collect additional 
PK samples from consenting participants. 
These additional visits can only be 
performed when all of the injections of that 
Added additional 
pharmacokinetic sampling 
visits to meet competent 
authority request for more 
PK sampling 
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treatment cycle are given at the site. 
Sampling will only be performed during a 
participant’s first and/or second treatment 
cycles. 
Section 8.4 
Pharmacokinetics 
Efgartigimod concentrations will be 
measured in all participants at study entry 
and 1 week after the last injection of each 
treatment cycle. 
The following PK parameters will be 
measured: concentration observed predose 
(Ctrough) of efgartigimod PH20 SC To 
characterize anticipated peak 
concentrations, efgartigimod concentrations 
will also be measured in a subset of at least 
12 participants who consent to additional 
sampling. These participants will perform 
additional on-site visits 2 days after their 
first and fourth injections in a treatment 
cycle. These additional visits can only be 
performed when all of the injections in a 
treatment cycle are given at the site. This 
sampling may only be performed during a 
participant’s first and/or second treatment 
cycles.  
Section 1.3 Schedule of 
Activities 
End of study visit study day changed 
728730 
Corrected the number of 
days to accurately reflect 
the study duration 
Footnote b 
This visit must always be performed at the site. 
All other visits can be performed by phone if 
IMP administration occurs at home.  
Clarified which visits are 
phone visits 
Footnote y 
The first dose administration of all TPs…may 
be performed at home. When IMP 
administration is performed at home, the 
associated visit will be performed by phone. 
Footnote u 
The PK assessments will only be taken at 
TP1V1. The assessment should be performed 
predose. only at TP1V1. 
Clarified the timing of the 
PK sampling 
Added row for “Blood sampling” 
Rearranged the Schedule 
of Activities to group the 
blood sampling together 
Section 1.1 Synopsis, 
Intervention Groups 
and Duration 
Footnote c in Figure 1 
Footnote d in Figure 2 
Clarified study duration 
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Section 1.2 Schema 
Section 1.3 Schedule of 
Activities 
 
Footnote f in Schedule of Activities 
The study will last for 2 years from the 
participant’s first visit in this study. 
Section 1.3 Schedule of 
Activities 
Section 6.6 Continued 
Access to Study 
Intervention After the 
End of the Study 
Footnote f in Schedule of Activities 
If efgartigimod becomes commercially 
available for patients with gMG or available 
through another patient program for gMG, 
participants will have the choice to switch to 1 
of these options after 1 year of participation in 
this long-term safety study. No treatment-free 
follow-up will be performed in this study, 
except for participants who do not want to 
continue receiving efgartigimod. 
Clarified procedures for 
continued access to IMP 
after the study 
Section 1.3 Schedule of 
Activities 
Section 6.4 Study 
Intervention 
Compliance 
Footnote x in Schedule of Activities 
Participants who have not previously self-
administered…only be performed on-site. At 
every on-site visit, the study staff must 
review the administration log and patient 
diary with the participant. 
Added the instruction to 
review the administration 
log and patient diary to 
check for compliance and 
adverse events 
Section 1.3 Schedule of 
Activities 
 
Footnote p 
Blood samples for clinical laboratory 
(hematology/clinical chemistry and FSH, if 
applicable) safety assessments will be 
collected. On dosing days, the samples will be 
taken predose. Participants need to be fasted 
(defined as no food or drink except for water, 
which is allowed until at least 4 hours prior to 
sampling) for at least 8 hours prior to each 
sampling. 
Clarified policy on taking 
permitted medications 
before each sampling. 
Aligned fasted definition 
with previous studies 
Section 1.3 Schedule of 
Activities 
Section 5.3 Lifestyle 
Considerations 
Footnote p in the Schedule of Activities 
Participants will need to be fasted for each on-
site visit at which safety laboratory 
assessments will be performed. Fasted is 
defined as no food or drink except for water, 
for at least 8 hours prior to the visit. Permitted 
medications that the participant normally 
takes can be taken as usual before a visit. 
Section 8.2.6.1 
Hematology, Clinical 
Chemistry, and 
Urinalysis 
Blood samples for clinical laboratory 
assessments will be taken while the participant 
is in the fasted condition, defined as no food or 
drink (except for water) for 8 hours. Water is 
permitted for up to 4 hours prior to the 
assessment. 
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Section 8.2.9.1 ADA 
Against Efgartigimod 
Section 8.2.9.2 ADA 
Against rHuPH20 
Section 8.2.10 Vaccine 
Antibody Titers and 
PBMCs 
The details of sampling, handling, storage, 
and transportation of the samples will be 
described in the laboratory manual. 
Added the location of the 
instructions for sampling 
Section 1.3 Schedule of 
Activities 
Section 8.2.10 Vaccine 
Antibody Titers and 
PBMCs 
Footnote r in the Schedule of Activities 
Additional blood samples (serum/peripheral 
blood mononuclear cells [PBMCs]) may need 
to be taken for 
additional/optional/future/vaccination 
research…occurred. In addition, if a participant 
consents to it, a whole-blood sample to isolate 
PBMCs will be collected at study entry and 
then approximately every 3 months throughout 
the study during a scheduled on-site visit, 
regardless of the vaccines a participant has 
received. 
Clarified that participants 
will have the option to 
consent to both serum and 
PBMC samples instead of 
one or the other. Added 
PBMC sampling at study 
entry 
Section 1.3 Schedule of 
Activities 
 
Footnote bb in the Schedule of Activities 
Adverse events, use of concomitant therapies, 
use of rescue therapy, medical procedures 
performed on participants, and hospitalizations 
will be collected informed consent signature 
until the last study-related activity. All 
available vaccination history for participants 
rolling over from ARGX-113-1705 will be 
captured as a part of the participant’s prior 
medication for vaccinations received in the past 
or concomitant medication for vaccinations 
received during the study. should be recorded 
in the eCRF. All vaccines received during 
the study should be recorded as concomitant 
medication. See Section 6.8 and Section 8.3 
Clarification on the 
recording of vaccination 
history and vaccines 
received during the study. 
Section 8.2.6 Clinical 
Safety Laboratory 
Assessments 
If laboratory values from nonprotocol specified 
laboratory tests performed at the institution’s 
local laboratory require a change in participant 
management or are considered clinically 
significant by the investigator and an SAE, 
then it the outcomes must be recorded on the 
SAE form. 
Simplified the text by 
removing redundant 
information 
Section 8.2.6.1 
Hematology, Clinical 
Chemistry 
Blood and urine samples for clinical safety 
laboratory assessments, including hematology, 
blood chemistry, and urinalysis, will be 
collected at the timepoints specified in the SoA 
(Section 1.3). The list of clinical safety 
laboratory parameters for hematology, clinical 
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chemistry, and urinalysis are provided in Table 
3. 
• 
Blood samples for clinical laboratory 
assessments will be taken while the 
participant is in the fasted condition, 
defined as no food or drink for 8 hours.  
• 
Blood samples for safety assessments 
will be collected according to the 
laboratory manual. 
• 
The samples will be analyzed at the 
central laboratory. 
Section 5.1 Inclusion 
Criteria 
Criterion 3.a. 
Male participants: 
Male participants are not allowed to donate 
sperm from signing the ICF through 90 days 
after the last dose of IMP until the end of the 
study. 
Updated contraceptive 
requirement to reflect new 
reproductive toxicity data 
Section 6.2.3 Storage 
The IMP will be supplied to the pharmacy at 
the designated investigational site by and under 
the responsibility of the sponsor’s designated 
IMP supply vendor. who will also provide The 
investigator will be provided with the 
certificate of analysis, certificate of conformity, 
and European Union qualified person release 
documents. 
Edited the information 
regarding supplying the 
IMP for clarity 
Section 6.4 Study 
Intervention 
Compliance 
Errors that are identified…without supervision. 
It will be evaluated if these dosing errors will 
be reported as protocol deviations in the 
clinical database. All supplies and pharmacy 
documentation must be made available 
throughout the study for the sponsor’s 
designated CRO monitor to review. 
Clarified administration 
error text. 
Section 1.2 Schema, 
Figures 1 and 2 
Section 6.5.1 
Retreatment Criteria 
Footnote a in the Schema 
There must be at least 7 weeks left in the 
study for the participant, so that a full TP 
and IP can be performed. 
Added a retreatment 
condition to restrict 
starting treatment periods 
near the end of the study 
so that participants can 
complete a full treatment 
cycle 
Section 6.7 Treatment 
of Overdose 
A participant must not miss more than 2 
consecutive doses and must not miss more than 
10% of the total planned doses. Furthermore, 
There must be at least 3 days between 
2 consecutive doses. 
Removed unnecessary 
restriction on missing 
doses 
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Section 6.8.1 Prior 
Medication and 
Procedures 
For participants rolling over from ARGX-113-
1705, all available vaccination history must be 
collected should be recorded in the eCRF. 
Any vaccination information that the 
participant or their caregiver can remember 
should be recorded in the eCRF with the 
brand name of the vaccine and date of 
vaccination, if possible. 
Added vaccination history 
collection information for 
participants entering the 
study from study ARGX-
113-1705 
Section 6.8.2 Permitted 
Concomitant 
Medication and 
Procedures 
Any vaccination within 28 days of study entry 
up until the end of the study during the study 
should be recorded in the eCRF with the brand 
name of the vaccine and the date of vaccine 
administration. 
Updated information on 
recording received 
vaccination so 
information can be used in 
a separate analysis 
Section 6.8.3 Prohibited 
Medications and 
Procedures 
In the first year of the study, participants are 
NOT allowed to do any of the following: 
… 
change increase the dose or frequency of an 
NSID 
Corrected prohibited 
medication rules for the 
first year of the study 
Section 8.2.6 Clinical 
Safety Laboratory 
Assessments 
See Section 10.2 for the list of…laboratory 
manual. The actual sample collection date and 
time will be collected and included in the 
central laboratory data transfer. 
Clarified data 
management procedures 
Section 1.3 Schedule of 
Activities 
Section 8.2.9.2 ADA 
Against rHuPH20 
Footnote s in Schedule of Activities 
If no sample was taken, the reason will be 
recorded in the relevant section of the eCRF. 
Section 1.3 Schedule of 
Activities 
 
Footnote s in Schedule of Activities 
Titers of ADA and the presence of NAbs 
against efgartigimod will be measured in 
serum. Blood samples for plasma titer levels of 
ADA and NAbs against rHuPH20 will also be 
taken. A titer for ADA and the presence of 
NAbs against PH20 must be measured at 
study entry for participants coming from 
ARGX-113-1705. 
Ensured immunogenicity 
sampling for participants 
entering this study from 
study ARGX-113-1705 
Section 8.2.9.2 ADA 
Against rHuPH20 
Blood samples will be collected to assess the 
serum levels of ADA against efgartigimod as 
indicated in the SoA (Section 1.3), including a 
sample taken at study entry for participants 
coming from study ARGX-113-1705. 
Section 1.3 Schedule of 
Activities 
Section 8.3.1 Time 
Period and Frequency 
Footnote bb of Schedule of Activities 
Adverse events (including ongoing AEs from 
the antecedent studies), use of concomitant 
therapies, use of rescue therapy, medical 
procedures performed on the participants, and 
hospitalizations will be collected from 
Added requirement for 
ongoing AE reporting 
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for Collecting AE and 
SAE Information 
informed consent signature until the last study-
related activity. 
All AEs and SAEs will be collected from the 
signing of the informed consent form until the 
EoS or the SFU visit at the time points 
specified in the SoA (Section 1.3). Ongoing 
AEs from the antecedent studies must also 
be recorded. 
Section 1.3 Schedule of 
Activities 
Footnote x in the Schedule of Activities 
Participants who have not previously self-
administered efgartigimod PH20 SC in study 
ARGX-113-2001 will be instructed on self-
administration as of TP1V1 or IP0V1 in study 
ARGX-113-2002. Training can continue until 
the participant or caregiver is ready to 
administer efgartigimod PH20 SC. Caregivers 
must sign the ICF before being trained in 
IMP administration.  
Added information for a 
caregiver ICF 
Section 1.1 Synopsis, 
Overall Design 
Section 4.1 Overall 
Design 
Efgartigimod PH20 SC will be administered… 
After signing an informed consent form and 
receiving the necessary training, the caregiver 
can administer the SC injections to the 
participant. 
Section 10.1.3 Informed 
Consent Process 
A separate ICF will be issued to all 
caregivers. Caregivers must sign the ICF 
before being trained in IMP administration. 
A copy of the signed and dated caregiver 
ICF(s) must be provided to the caregiver. 
… 
The investigator is responsible for ensuring that 
informed consent is obtained from each 
participant and for obtaining the appropriate 
signatures and dates on the ICF prior to the 
performance of any protocol procedures and 
prior to the administration of the IMP. 
Section 1.3 Schedule of 
Activities 
Added row for “Specialty laboratory tests” 
and footnote q 
Samples for specialty laboratory tests will be 
taken at the baseline, the IP1V1 visit, and the 
next on-site visit that is at least 4 weeks after 
the participant’s fourth dose (TP1V4). See 
Section 10.2.1. 
Added assessments to 
further investigate the 
effect of the IMP on lipid 
metabolism 
Section 10.2.1 Specialty 
Laboratory Tests 
At the visits listed in the SoA, blood will be 
sampled under fasting conditions for 
specialty laboratory parameters that may 
include but not be limited to apolipoprotein 
B (apoB), lipoprotein A, fibrinogen, von 
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Willebrand factor, d-dimer, proprotein 
convertase subtilisin/kexin type 9 serine 
protease (PCSK9). 
These parameters will be analyzed by the 
central laboratory. 
Section 10.1.8 Source 
Documents 
Source documents provide evidence for the 
existence of the participant and substantiate the 
integrity of the data collected. Source 
documents are filed at the investigator’s site. 
The investigator/institution should maintain 
a record of the location(s) of their respective 
essential documents, including source 
documents. 
… 
The definition of what constitutes source data 
can be found in the investigator source data 
agreement data management plan. 
Clarified guidance around 
recording the source 
document locations and 
the location of the 
definition of what is 
considered source data 
Section 10.3 Appendix 
3: Total Blood Volume 
Collected From Each 
Participant 
The maximum amount of blood collected from 
each participant is 815 mL 1493.4 mL. 
Updated the maximum 
blood volume from each 
participant based on the 
updated PK sampling 
schedule 
Section 10.6 Appendix 
6: Administrative 
Structure, Table 4 
Edited addresses for Covance Bioanalytical 
Services LLC, Fisher Clinical Services, SGS 
Life Sciences 
Added EastHORN Clinical Service and 
EndPoint as vendors 
Updated vendor 
information 
Section 10.7.3.3 Study 
Protocol Changes 
If the COVID-19 pandemic results in 
participants being unable to visit the site, a 
home nurse can perform visits that are 
mandatory to be performed at the site (Section 
10.7.3.5). A home nurse will be a qualified 
person from either the study site staff or a 
home health care vendor. If a home nurse is 
being used, the visits can take place at the 
participant’s home or an alternative location 
agreed upon by both parties. A participant 
must consent to performing study visits with 
a home nurse from the home health care 
vendor. The use of a home nurse will depend 
on regional availability. Study staff will 
follow-up with participants who participate 
in offsite study visits using the home health 
care vendor. 
Added information 
regarding home nurse 
during the COVID-19 
pandemic 
Section 10.8.1 
Appendix 8 Definitions 
Baseline: the data collected prior to the first 
dose of efgartigimod in the antecedent studies 
Changed the definition of 
baseline to align with 
previous clinical studies 
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ARGX 113 2001, ARGX 113 1704, or 
ARGX 113 1705 this study 
Section 10.9 Protocol 
Amendment History 
Added the following change to Section 8.2.6.2 
to Summary of Changes 
Participants should only be tested after the 
IP0V1 visit if they have symptoms of COVID-
19 or if they were in contact with someone who 
tested positive for SARS-CoV-2, unless local 
or site regulations have more stringent testing 
requirements. 
Added a previously 
omitted change to the 
Summary of Changes 
from the previous protocol 
version 
 
10.8.5. 
Summary of Changes Between Protocol Version 1.0 and Protocol Version 1.5-
GER 
 
Overall Rationale for the Changes in Protocol Version 1.5-Germany 
The overall rationale for the changes implemented in this protocol version is to conform to the 
requirements set forth by the competent authorities and ethics committees.  
The major changes from Protocol Version 1 compared with Protocol Version 1.5–Germany are 
summarized in the following table. A double strikethrough indicates deleted text and a bold font 
indicates added text. Minor editorial changes and document formatting revisions have not been 
summarized. 
 
Section and Name 
Description of Change 
Brief Rationale 
Section 1.3 Schedule of 
Activities 
Addition of specific first visit IP0V1 
Marked with footnotes a and b 
Removed footnote a from TPnV1 and IPnVm 
visits 
Added an obligatory 
treatment-free visit at the 
start of the study to test 
for SARS-CoV-2 before 
IMP  
Footnote p 
A nasopharyngeal swab will be performed to 
sample nasal and throat mucosal cells. 
Participants must be tested for SARS-CoV-2 
at study entry. Participants should be tested 
for SARS-CoV-2 if they have symptoms of 
COVID-19 or if they were in contact with a 
person who tested positive for SARS-CoV-2, 
unless local or site regulations have more 
stringent testing requirements. Participants may 
be retested as needed. 
Removal of footnote g 
These activities are only performed at study 
entry. 
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Section and Name 
Description of Change 
Brief Rationale 
Footnote a 
The transition from the antecedent studies 
ARGX-113-1705 or ARGX-113-2001 to study 
ARGX-113-2002 can either will be IP0V1 or 
TP1V1, depending on the need for retreatment. 
Section 1.1 Synopsis 
Eligible participants will enter the study on 
their last visit of the antecedent study, 
ARGX-113-2001 or ARGX-113-1705. 
Participants will enter the study with an IP 
visit (IP0V1). Once the results of the 
SARS-CoV-2 test from that visit are 
available, If they are in need of retreatment, 
the participants will start a TP if they are in 
need of retreatment and test negative for 
SARS-CoV-2. A TP will consist of an 
injection of efgartigimod PH20 SC 1000 mg 
q7d for a total of 4 injections. If the 
participants are not in need of retreatment, they 
will start continue with an IP visits 
(ie, visit IP0V12). 
Section 1.2 Schema 
Updated Figure 1 to include IP0V1 
Footnote a 
Participants will receive efgartigimod PH20 SC 
1000 mg q7d for 4 injections. A new TP can be 
started if the participant is in need of 
retreatment as determined by the investigator, 
has tested negative for SARS-CoV-2, and at 
least 28 days have elapsed since the last dose 
of efgartigimod. 
Section 4.1 Overall 
Design 
At study entry, participants will be evaluated 
for the start with the IP0V1 visit, which will 
include a SARS-CoV-2 test and an 
evaluation of the participant’s need of for 
retreatment. If a participant is in need of 
retreatment and has tested negative for 
SARS-CoV-2, the next visit will become the 
first visit of the first TP. If a participant is not 
in need of retreatment, the next visit will be an 
IP visit. 
Section 5.4 Screen 
Failures 
Eligibility to roll over into study 
ARGX-113-2002 will must be verified 
assessed at the last IP0V1 visit of the 
antecedent studies ARGX 113 2001 or 
ARGX-113-1705, which acts as the first visit 
of this study. 
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Section and Name 
Description of Change 
Brief Rationale 
Section 8.2.6.2 
SARS-CoV-2 Test 
Nasal and throat mucosal cell samples will be 
collected according to the laboratory manual at 
the time points start of the study and as 
needed after study entry to be tested test for 
SARS-CoV-2. Participants should only be 
tested after the IP0V1 visit if they have 
symptoms of COVID-19 or if they were in 
contact with someone who tested positive for 
SARS-CoV-2, unless local or site regulations 
have more stringent testing requirements. 
Section 10.2 Appendix 
2: Clinical Laboratory 
Tests, Table 3 
Changed the category of the SARS-CoV-2 test 
from “Unscheduled Test” to “Eligibility 
Assessment” 
Section 10.7.3.2 
Testing for COVID-19 
Testing for COVID-19 beyond what is 
indicated in Table 1, described in Section 
8.2.6.2, and mandated by the relevant local 
authorities is not required during the study. 
… 
At study entry, if the participant cannot come 
to the site due to COVID 19 infection or travel 
restrictions, the ICF can be signed remotely 
when allowed by local regulations. A positive 
SARS-CoV-2 test at study entry is 
exclusionary. If a participant is infected with 
COVID-19 during the study, they cannot be 
(re)treated until they no longer test positive for 
SARS-CoV-2. These participants can still enter 
the ARGX 113 2002 study by entering an IP. 
Section 5.2 Exclusion 
Criteria 
Exclusion criterion 3 
A positive test for SARS-CoV-2 at IP0V1 
Added an exclusion 
criterion for being 
infected with SARS-CoV-
2 
Section 5.2 Exclusion 
Criteria 
Exclusion criteria 7 and 8 
The participant stands in any relationship of 
dependency with the sponsor. 
The participant has been institutionalized 
due to an official or judicial order. 
Added exclusion criteria 
to comply with Section 7 
(3), No. 4 GCP 
Regulation and Section 40 
Para. 1 S.3 No. 4 AMG 
(German Drug Law), 
respectively 
Section 10.1.9 Study 
and Site Start and 
Closure 
For study termination: 
• 
Discontinuation of further study 
intervention development 
• 
An unexpected negative change to 
the benefit-risk profile of the IMP 
Added additional criteria 
for study termination 
based on feedback 
received from the ethics 
committee 
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Section and Name 
Description of Change 
Brief Rationale 
• 
Recommendation of termination by 
the DSMB 
• 
A necessary adjustment to the 
maximum insured sum for the study 
that is not possible 
• 
The approvals given by the 
regulatory agencies and/or IRB/IEC 
are withdrawn 
Section 10.5.2.1 Female 
Contraception for 
Women of Childbearing 
Potential 
Sexual abstinence is considered a highly 
effective method only if defined as refraining 
from heterosexual intercourse during the 
entire period of risk associated with the 
study intervention. The reliability of sexual 
abstinence needs to be evaluated in relation 
to the duration of the study and the 
preferred and usual lifestyle of the 
participant. 
Added more information 
about sexual abstinence as 
a highly effective method 
of contraception 
 
 
 
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10.9. 
Appendix 9: Summary of Changes Between Protocol Version 1.0 and 
Protocol Version 2.0 
Overall Rationale for the Changes in Protocol Version 2.0 
The overall rationale for this amendment includes adding additional optional pharmacokinetic 
samples from a subset of participants to better evaluate the pharmacokinetics of the 
investigational medicinal product (IMP), as requested by competent authorities. Additionally, 
more clinical chemistry laboratory assessments have been added to evaluate the effect of the IMP 
on lipid panels. 
The major changes from protocol version 1.0 compared with protocol version 2.0 are 
summarized in the following table. A double strikethrough indicates text that was removed and 
bolded text indicates text that was added. Minor editorial changes, including the correction of 
typographical errors and formatting inconsistencies, are not summarized. 
 
Section and Name 
Description of Change 
Brief Rationale 
Title Page 
Industriepark Zwijnaarde 7 
B 9052 Zwijnaarde (Ghent) 
Belgium 
Corrected argenx address 
Added name and affiliation of 
principal/coordinating investigator 
Added Investigator’s Agreement and signature 
Integrated investigator 
information into protocol 
Emergency Contact 
Information 
Added the Emergency Contact Information 
section with information about SAE reporting 
Updated email address 
and fax number for 
reporting SAEs 
Section 1.1 Synopsis, 
Objectives and 
Endpoints 
Section 3 Objectives 
and Endpoints 
Incidence and severity of adverse events (AEs), 
incidence of serious adverse events (SAEs), 
and AEs of special interest (AESIs), and 
changes in laboratory test results, physical 
examination results, vital signs, and 
electrocardiogram results 
Edited endpoints for 
clarity 
 
 
 
Added secondary objective and endpoint 
Objective: 
To evaluate the PK of efgartigimod PH20 
SC 
Endpoint: 
Efgartigimod serum concentrations 
Added an objective and 
endpoint to assess the PK 
with the additional 
optional PK assessments. 
Section 1.1 Synopsis, 
Overall Design 
A caregiver is a person of legal age from the 
participant’s social network (eg, family, 
relatives, friends) introduced by the 
Added the definition of 
the caregiver 
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Section and Name 
Description of Change 
Brief Rationale 
Section 4.1 Overall 
Design  
Section 10.8.1 
Definitions 
participant. After receiving the necessary 
training, the caregiver can administer the 
SC injections to the participant. 
Section 4.1 Overall 
Design 
The total study duration is 2 years from the 
participant’s first visit in this study: 
• 
3-week treatment periods (TPs), 
repeated as needed based on the 
clinical effect, with a maximum of 14 
TPs 
Added information 
contained in the synopsis 
to the body of the protocol 
Section 1.1 Synopsis 
Section 9.2 Sample Size 
Determination 
“Enrolled” means a participant’s, or their 
legally acceptable representative’s, agreement 
to participate in a clinical study following 
completion of the informed consent process 
and screening. 
Removed references to the 
participant’s legally 
authorized or legally 
acceptable representative 
that are not appliable to 
this study. 
Section 8.3 Adverse 
Events, Serious 
Adverse Events, and 
Other Safety Reporting 
AEs will be reported by the participant (or, 
when appropriate, by a caregiver, or surrogate, 
or the participant’s legally authorized 
representative). 
Section 1.3 Schedule of 
Activities 
Added 2 visits, PK1 and PK2, to take place 
2 days after the first and fourth dose in a 
treatment period, respectively. These visits 
have “Pharmacokinetics” activity row checked. 
Added footnote c 
These are optional visits to collect additional 
PK samples from consenting participants. 
These additional visits can only be 
performed when all of the injections of that 
treatment cycle are given at the site. 
Sampling will only be performed during a 
participant’s first and/or second treatment 
cycles. 
Added additional 
pharmacokinetic sampling 
visits to meet competent 
authority request for more 
PK sampling 
Section 8.4 
Pharmacokinetics 
Efgartigimod concentrations will be 
measured in all participants at study entry 
and 1 week after the last injection of each 
treatment cycle. 
The following PK parameters will be 
measured: concentration observed predose 
(Ctrough) of efgartigimod PH20 SC To 
characterize anticipated peak 
concentrations, efgartigimod concentrations 
will also be measured in a subset of at least 
12 participants who consent to additional 
sampling. These participants will perform 
additional on-site visits 2 days after their 
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Section and Name 
Description of Change 
Brief Rationale 
first and fourth injections in a treatment 
cycle. These additional visits can only be 
performed when all of the injections in a 
treatment cycle are given at the site. This 
sampling may only be performed during a 
participant’s first and/or second treatment 
cycles.  
Section 1.3 Schedule of 
Activities 
End of study visit study day changed 
728730 
Corrected the number of 
days to accurately reflect 
the study duration 
Footnote b 
This visit must always be performed at the site. 
All other visits can be performed by phone if 
IMP administration occurs at home.  
Clarified which visits are 
phone visits 
Footnote y 
The first dose administration of all TPs…may 
be performed at home. When IMP 
administration is performed at home, the 
associated visit will be performed by phone. 
Footnote u 
The PK assessments will only be taken at 
TP1V1. The assessment should be performed 
predose. only at TP1V1. 
Clarified the timing of the 
PK sampling 
Added row for “Blood sampling” 
Rearranged the Schedule 
of Activities to group the 
blood sampling together 
Section 1.1 Synopsis, 
Intervention Groups 
and Duration 
Section 1.2 Schema 
Section 1.3 Schedule of 
Activities 
 
Footnote c in Figure 1 
Footnote d in Figure 2 
Footnote f in Schedule of Activities 
The study will last for 2 years from the 
participant’s first visit in this study. 
Clarified study duration 
Section 1.3 Schedule of 
Activities 
Section 6.6 Continued 
Access to Study 
Intervention After the 
End of the Study 
Footnote f in Schedule of Activities 
If efgartigimod becomes commercially 
available for patients with gMG or available 
through another patient program for gMG, 
participants will have the choice to switch to 1 
of these options after 1 year of participation in 
this long-term safety study. No treatment-free 
follow-up will be performed in this study, 
except for participants who do not want to 
continue receiving efgartigimod. 
Clarified procedures for 
continued access to IMP 
after the study 
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Section and Name 
Description of Change 
Brief Rationale 
Section 1.3 Schedule of 
Activities 
Section 6.4 Study 
Intervention 
Compliance 
Footnote x in Schedule of Activities 
Participants who have not previously self-
administered…only be performed on-site. At 
every on-site visit, the study staff must 
review the administration log and patient 
diary with the participant. 
Added the instruction to 
review the administration 
log and patient diary to 
check for compliance and 
adverse events 
Section 1.3 Schedule of 
Activities 
 
Footnote p 
Blood samples for clinical laboratory 
(hematology/clinical chemistry and FSH, if 
applicable) safety assessments will be 
collected. On dosing days, the samples will be 
taken predose. Participants need to be fasted 
(defined as no food or drink except for water, 
which is allowed until at least 4 hours prior to 
sampling) for at least 8 hours prior to each 
sampling. 
Clarified policy on taking 
permitted medications 
before each sampling. 
Aligned fasted definition 
with previous studies 
Section 1.3 Schedule of 
Activities 
Section 5.3 Lifestyle 
Considerations 
Footnote p in the Schedule of Activities 
Participants will need to be fasted for each on-
site visit at which safety laboratory 
assessments will be performed. Fasted is 
defined as no food or drink except for water, 
for at least 8 hours prior to the visit. Permitted 
medications that the participant normally 
takes can be taken as usual before a visit. 
Section 8.2.6.1 
Hematology, Clinical 
Chemistry, and 
Urinalysis 
Blood samples for clinical laboratory 
assessments will be taken while the participant 
is in the fasted condition, defined as no food or 
drink (except for water) for 8 hours. Water is 
permitted for up to 4 hours prior to the 
assessment. 
Section 8.2.9.1 ADA 
Against Efgartigimod 
Section 8.2.9.1 ADA 
Against rHuPH20 
Section 8.2.10 Vaccine 
Antibody Titers and 
PBMCs 
The details of sampling, handling, storage, 
and transportation of the samples will be 
described in the laboratory manual. 
Added the location of the 
instructions for sampling 
Section 1.3 Schedule of 
Activities 
Section 8.2.10 Vaccine 
Antibody Titers and 
PBMCs 
Footnote r in the Schedule of Activities 
Additional blood samples (serum/peripheral 
blood mononuclear cells [PBMCs]) may need 
to be taken for 
additional/optional/future/vaccination 
research…occurred. In addition, if a participant 
consents to it, a whole-blood sample to isolate 
PBMCs will be collected at study entry and 
Clarified that participants 
will have the option to 
consent to both serum and 
PBMC samples instead of 
one or the other. Added 
PBMC sampling at study 
entry 
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Section and Name 
Description of Change 
Brief Rationale 
then approximately every 3 months throughout 
the study during a scheduled on-site visit, 
regardless of the vaccines a participant has 
received. 
Section 1.3 Schedule of 
Activities 
 
Footnote bb in the Schedule of Activities 
Adverse events, use of concomitant therapies, 
use of rescue therapy, medical procedures 
performed on participants, and hospitalizations 
will be collected informed consent signature 
until the last study-related activity. All 
available vaccination history for participants 
rolling over from ARGX-113-1705 will be 
captured as a part of the participant’s prior 
medication for vaccinations received in the past 
or concomitant medication for vaccinations 
received during the study. should be recorded 
in the eCRF. All vaccines received during 
the study should be recorded as concomitant 
medication. See Section 6.8 and Section 8.3 
Clarification on the 
recording of vaccination 
history and vaccines 
received during the study. 
Section 8.2.6 Clinical 
Safety Laboratory 
Assessments 
If laboratory values from nonprotocol specified 
laboratory tests performed at the institution’s 
local laboratory require a change in participant 
management or are considered clinically 
significant by the investigator and an SAE, 
then it the outcomes must be recorded on the 
SAE form. 
Simplified the text by 
removing redundant 
information 
Section 8.2.6.1 
Hematology, Clinical 
Chemistry 
Blood and urine samples for clinical safety 
laboratory assessments, including hematology, 
blood chemistry, and urinalysis, will be 
collected at the timepoints specified in the SoA 
(Section 1.3). The list of clinical safety 
laboratory parameters for hematology, clinical 
chemistry, and urinalysis are provided in Table 
3. 
• 
Blood samples for clinical laboratory 
assessments will be taken while the 
participant is in the fasted condition, 
defined as no food or drink for 8 hours.  
• 
Blood samples for safety assessments 
will be collected according to the 
laboratory manual. 
• 
The samples will be analyzed at the 
central laboratory. 
Section 5.1 Inclusion 
Criteria 
Criterion 3.a. 
Male participants: 
Updated contraceptive 
requirement to reflect new 
reproductive toxicity data 
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Section and Name 
Description of Change 
Brief Rationale 
Male participants are not allowed to donate 
sperm from signing the ICF through 90 days 
after the last dose of IMP until the end of the 
study. 
Section 6.2.3 Storage 
The IMP will be supplied to the pharmacy at 
the designated investigational site by and under 
the responsibility of the sponsor’s designated 
IMP supply vendor. who will also provide The 
investigator will be provided with the 
certificate of analysis, certificate of conformity, 
and European Union qualified person release 
documents. 
Edited the information 
regarding supplying the 
IMP for clarity 
Section 6.4 Study 
Intervention 
Compliance 
Errors that are identified…without supervision. 
It will be evaluated if these dosing errors will 
be reported as protocol deviations in the 
clinical database. All supplies and pharmacy 
documentation must be made available 
throughout the study for the sponsor’s 
designated CRO monitor to review. 
Clarified administration 
error text. 
Section 1.2 Schema, 
Figures 1 and 2 
Section 6.5.1 
Retreatment Criteria 
Footnote a in the Schema 
There must be at least 7 weeks left in the 
study for the participant, so that a full TP 
and IP can be performed. 
Added a retreatment 
condition to restrict 
starting treatment periods 
near the end of the study 
so that participants can 
complete a full treatment 
cycle 
Section 6.7 Treatment 
of Overdose 
A participant must not miss more than 2 
consecutive doses and must not miss more than 
10% of the total planned doses. Furthermore, 
There must be at least 3 days between 
2 consecutive doses. 
Removed unnecessary 
restriction on missing 
doses 
Section 6.8.1 Prior 
Medication and 
Procedures 
For participants rolling over from ARGX-113-
1705, all available vaccination history must be 
collected should be recorded in the eCRF. 
Any vaccination information that the 
participant or their caregiver can remember 
should be recorded in the eCRF with the 
brand name of the vaccine and date of 
vaccination, if possible. 
Added vaccination history 
collection information for 
participants entering the 
study from study ARGX-
113-1705 
Section 6.8.2 Permitted 
Concomitant 
Medication and 
Procedures 
Any vaccination within 28 days of study entry 
up until the end of the study during the study 
should be recorded in the eCRF with the brand 
name of the vaccine and the date of vaccine 
administration. 
Updated information on 
recording received 
vaccination so 
information can be used in 
a separate analysis 
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Section and Name 
Description of Change 
Brief Rationale 
Section 6.8.3 Prohibited 
Medications and 
Procedures 
In the first year of the study, participants are 
NOT allowed to do any of the following: 
… 
change increase the dose or frequency of an 
NSID 
Corrected prohibited 
medication rules for the 
first year of the study 
Section 8.2.6 Clinical 
Safety Laboratory 
Assessments 
See Section 10.2 for the list of…laboratory 
manual. The actual sample collection date and 
time will be collected and included in the 
central laboratory data transfer. 
Clarified data 
management procedures 
Section 1.3 Schedule of 
Activities 
Section 8.2.9.2 ADA 
Against rHuPH20 
Footnote s in Schedule of Activities 
If no sample was taken, the reason will be 
recorded in the relevant section of the eCRF. 
Section 1.3 Schedule of 
Activities 
 
Footnote s in Schedule of Activities 
Titers of ADA and the presence of NAbs 
against efgartigimod will be measured in 
serum. Blood samples for plasma titer levels of 
ADA and NAbs against rHuPH20 will also be 
taken. A titer for ADA and the presence of 
NAbs against PH20 must be measured at 
study entry for participants coming from 
ARGX-113-1705. 
Ensured immunogenicity 
sampling for participants 
entering this study from 
study ARGX-113-1705 
Section 8.2.9.2 ADA 
Against rHuPH20 
Blood samples will be collected to assess the 
serum levels of ADA against efgartigimod as 
indicated in the SoA (Section 1.3), including a 
sample taken at study entry for participants 
coming from study ARGX-113-1705. 
Section 1.3 Schedule of 
Activities 
Section 8.3.1 Time 
Period and Frequency 
for Collecting AE and 
SAE Information 
Footnote bb of Schedule of Activities 
Adverse events (including ongoing AEs from 
the antecedent studies), use of concomitant 
therapies, use of rescue therapy, medical 
procedures performed on the participants, and 
hospitalizations will be collected from 
informed consent signature until the last study-
related activity. 
All AEs and SAEs will be collected from the 
signing of the informed consent form until the 
EoS or the SFU visit at the time points 
specified in the SoA (Section 1.3). Ongoing 
AEs from the antecedent studies must also 
be recorded. 
Added requirement for 
ongoing AE reporting 
Section 1.3 Schedule of 
Activities 
Footnote x in the Schedule of Activities 
Participants who have not previously self-
administered efgartigimod PH20 SC in study 
Added information for a 
caregiver ICF 
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Section and Name 
Description of Change 
Brief Rationale 
ARGX-113-2001 will be instructed on self-
administration as of TP1V1 or IP0V1 in study 
ARGX-113-2002. Training can continue until 
the participant or caregiver is ready to 
administer efgartigimod PH20 SC. Caregivers 
must sign the ICF before being trained in 
IMP administration.  
Section 1.1 Synopsis, 
Overall Design 
Section 4.1 Overall 
Design 
Efgartigimod PH20 SC will be administered… 
After signing an informed consent form and 
receiving the necessary training, the caregiver 
can administer the SC injections to the 
participant. 
Section 10.1.3 Informed 
Consent Process 
A separate ICF will be issued to all 
caregivers. Caregivers must sign the ICF 
before being trained in IMP administration. 
A copy of the signed and dated caregiver 
ICF(s) must be provided to the caregiver. 
… 
The investigator is responsible for ensuring that 
informed consent is obtained from each 
participant and for obtaining the appropriate 
signatures and dates on the ICF prior to the 
performance of any protocol procedures and 
prior to the administration of the IMP. 
Section 1.3 Schedule of 
Activities 
Added row for “Specialty laboratory tests” 
and footnote q 
Samples for specialty laboratory tests will be 
taken at the baseline, the IP1V1 visit, and the 
next on-site visit that is at least 4 weeks after 
the participant’s fourth dose (TP1V4). See 
Section 10.2.1. 
Added assessments to 
further investigate the 
effect of the IMP on lipid 
metabolism 
Section 10.2.1 Specialty 
Laboratory Tests 
At the visits listed in the SoA, blood will be 
sampled under fasting conditions for 
specialty laboratory parameters that may 
include but not be limited to apolipoprotein 
B (apoB), lipoprotein A, fibrinogen, von 
Willebrand factor, d-dimer, proprotein 
convertase subtilisin/kexin type 9 serine 
protease (PCSK9). 
These parameters will be analyzed by the 
central laboratory. 
Section 10.1.8 Source 
Documents 
Source documents provide evidence for the 
existence of the participant and substantiate the 
integrity of the data collected. Source 
documents are filed at the investigator’s site. 
The investigator/institution should maintain 
Clarified guidance around 
recording the source 
document locations and 
the location of the 
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Section and Name 
Description of Change 
Brief Rationale 
a record of the location(s) of their respective 
essential documents, including source 
documents. 
… 
The definition of what constitutes source data 
can be found in the investigator source data 
agreement data management plan. 
definition of what is 
considered source data 
Section 10.3 Appendix 
3: Total Blood Volume 
Collected From Each 
Participant 
The maximum amount of blood collected from 
each participant is 815 mL 1493.4 mL. 
Updated the maximum 
blood volume from each 
participant based on the 
updated PK sampling 
schedule 
Section 10.5.2 
Appendix 5: 
Contraception 
Guidance 
Sexual abstinence is considered a highly 
effective method only if defined as refraining 
from heterosexual intercourse during the 
entire period of risk associated with the 
study intervention. The reliability of sexual 
abstinence needs to be evaluated in relation 
to the duration of the study and the 
preferred and usual lifestyle of the 
participant. 
Provided more 
information about sexual 
abstinence as a 
contraception method 
Section 10.6 Appendix 
6: Administrative 
Structure, Table 4 
Edited addresses for Covance Bioanalytical 
Services LLC, Fisher Clinical Services, SGS 
Life Sciences 
Added EastHORN Clinical Service and 
EndPoint as vendors 
Updated vendor 
information 
Section 10.7.3.3 Study 
Protocol Changes 
If the COVID-19 pandemic results in 
participants being unable to visit the site, a 
home nurse can perform visits that are 
mandatory to be performed at the site (Section 
10.7.3.5). A home nurse will be a qualified 
person from either the study site staff or a 
home health care vendor. If a home nurse is 
being used, the visits can take place at the 
participant’s home or an alternative location 
agreed upon by both parties. A participant 
must consent to performing study visits with 
a home nurse from the home health care 
vendor. The use of a home nurse will depend 
on regional availability. Study staff will 
follow-up with participants who participate 
in offsite study visits using the home health 
care vendor. 
Added information 
regarding home nurse 
during the COVID-19 
pandemic 
Section 10.8.1 
Appendix 8 Definitions 
Baseline: the data collected prior to the first 
dose of efgartigimod in the antecedent studies 
Changed the definition of 
baseline to align with 
previous clinical studies 
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Section and Name 
Description of Change 
Brief Rationale 
ARGX 113 2001, ARGX 113 1704, or 
ARGX 113 1705 this study 
 
 
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11. 
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