A Phase 2a, Multicenter, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of MK-6194 in Adult Participants With Non-Segmental Vitiligo
Phase: PHASE2
Conditions: Non-segmental Vitiligo
Sponsor: Merck Sharp & Dohme LLC

Official Protocol Title: 
NCT number: 
NCT06113328 
Document Date: 
09-April-2024
A Phase 2a, Multicenter, Randomized, Double-blind, Placebo-
controlled Study to Evaluate the Efficacy and Safety of 
MK-6194 in Adult Participants with Non-Segmental Vitiligo

PRODUCT: MK-6194
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TITLE PAGE
THIS PROTOCOL AND ALL OF THE INFORMATION RELATING TO IT ARE 
CONFIDENTIAL AND PROPRIETARY PROPERTY OF MERCK SHARP & 
DOHME LLC, RAHWAY, NJ, USA (MSD).
Protocol Title: A Phase 2a, Multicenter, Randomized, Double-blind, Placebo-controlled 
Study to Evaluate the Efficacy and Safety of MK-6194 in Adult Participants with Non-
Segmental Vitiligo
Protocol Number: 007-02
Compound Number: MK-6194
Sponsor Name: Merck Sharp & Dohme LLC
(hereafter called the Sponsor or MSD)
Legal Registered Address:
126 East Lincoln Avenue
P.O. Box 2000
Rahway, NJ 07065 USA
Regulatory Agency Identifying Number(s):
NCT
06113328
EU CT
2023-503502-37-00
EudraCT
Not applicable
JRCT
JRCT2031230622
WHO
Not applicable
UTN
U1111-1287-4329
IND
165557
Approval Date: 09 April 2024
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Sponsor Signatory
Typed Name:
Title:
Date
Protocol-specific Sponsor contact information can be found in the Investigator Study 
File Binder (or equivalent).
Investigator Signatory
I agree to conduct this clinical study in accordance with the design outlined in this protocol 
and to abide by all provisions of this protocol.
Typed Name:
Title:
Date
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DOCUMENT HISTORY
Document
Date of Issue
Overall Rationale
Amendment 02
09-APR-2024
This amendment was created to enhance 
requirements for HBV safety monitoring. 
Amendment 01
08-DEC-2023
This amendment was created to fulfill a request 
by the health authority in France. 
Original Protocol
27-JUL-2023
Not applicable
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PROTOCOL AMENDMENT SUMMARY OF CHANGES
Amendment: 02
Overall Rationale for the Amendment:
This amendment was created to enhance requirements for HBV safety monitoring.
Summary of Changes Table:
Section Number and 
Name
Description of Change
Brief Rationale
Primary Reason for the Amendment
Section 8.3.8, HBV, HCV, 
and HIV Testing
Comprehensive description 
of HBV testing and test result 
interpretation was added.
Strategic update to enhance 
requirements for HBV safety 
monitoring and clarity in the 
requirements for study entry.
Additional Changes
Section Number and 
Name
Description of Change
Brief Rationale
Title Page
NCT and JRCT numbers 
were added.
Regulatory agency 
identifying numbers are now 
available.
Section 1.3, Schedule of 
Activities
Day row was added to all 
subsections of the SoA.
To ensure clarity of 
day/week for scheduling 
purposes.
Section 1.3.1, Double-
Blind Treatment Period 
Verbal review at TC was 
added to the Participant 
Reminder Log:
review/collect row.
Clarification of expectations 
during TC visits.
Reference to Section 8.3.8 
was added to the HIV, HBV, 
and HCV testing row.
Refer to rationale for change
in Section 8.3.8. 
A separate row for 
HBV-DNA testing was 
added.
Refer to rationale for change 
in Section 8.3.8. 
TB testing note was 
shortened. Readers are 
directed to Section 8.3.6 and 
Section 5.2.
Note directing readers to 
updated TB testing 
information. 
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Section Number and 
Name
Description of Change
Brief Rationale
Section 1.3.2, Blinded 
Extension Period
Removed Week 54 scheduled 
time for conducting the 
Follow-up TC and added 
+7-day window. 
Follow-up TC should be 
conducted 28 days after last 
dose of study intervention.
Verbal review at TC was 
added to the Participant 
Reminder Log:
review/collect row.
Refer to rationale for change 
in Section 1.3.1.
A row for HBV-DNA testing 
was added. 
Refer to rationale for change 
in Section 8.3.8. 
Section 2.1, Study 
Rationale
Description of vitiligo 
disease activity was 
expanded.
Clarified definition of 
disease activity.
Section 4.1, Overall 
Design
Clarified that participants
will stay in the study unless 
consent is withdrawn.
Updated for protocol 
consistency.
Modified text to indicate that 
participants will alternate 
between placebo and 
MK-6194.
Placebo and MK-6194 are 
both considered study 
interventions.
Modified the text to indicate 
that enrollment for the 
PK/PD/Biomarker sampling 
will be at least 15 
participants per arm.
To avoid misunderstanding 
the number of subpopulation 
participants.
Added definition of follow-
up safety TC. 
Refer to rationale for change 
in Section 1.3.2 regarding 
follow-up TC. 
Section 4.2.1.3, 
Pharmacokinetic 
Endpoints
Modified the text to indicate 
that enrollment for the 
PK/PD/Biomarker sampling 
will be at least 15 
participants per arm.
Refer to rationale for change 
in Section 4.1.
Section 4.2.1.4, 
Pharmacodynamic 
Endpoints
Modified the text to indicate 
that enrollment for the 
PK/PD/Biomarker sampling 
will be at least 15 
participants per arm.
Refer to rationale for change 
in Section 4.1.
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Section Number and 
Name
Description of Change
Brief Rationale
Section 4.2.1.6, Planned 
Exploratory Biomarker 
Research
Removed microbiome 
analysis. 
Not applicable to this study.
Section 5.2, Exclusion 
Criteria
In exclusion criterion #12, 
HBV-DNA testing 
description was added, and 
the HCV definition was 
updated.
Refer to rationale for change 
in Section 8.3.8.
Moved QuantiFERON-TB
Gold testing guidance from 
criterion #13 to 
corresponding Section 8.3.6.
To clarify study entry 
guidance and initial TB 
retesting. 
In exclusion criterion #19, 
Table 1 Prohibited 
Medications, the 5-drug half-
lives period of phototherapy 
was deleted. 
Phototherapy does not have a 
half-life.
A footnote was added to 
Table 1 Prohibited 
Medications to indicate that 
medications are prohibited 
until the last dose of study 
intervention is administered.
Updated to align with 
Sections 6.5 and 8.1.5.2.
Section 6.3.1, Intervention 
Assignment
Modified text to indicate that 
participants will alternate 
between placebo and 
MK-6194.
Refer to Section 4.1 rationale
regarding study intervention. 
Section 6.3.2, Stratification
Descriptions of stratification 
factors were expanded.
Updated to address
investigator/site feedback. 
Section 7.1, 
Discontinuation of Study 
Intervention
Added criterion for 
discontinuation if HBV-DNA
is ≥LLOQ.
Refer to rationale for change 
in Section 8.3.8.
Section 8.1.1.3, Consent 
for PK/PD/Biomarker 
Subpopulation
Text added to indicate 
PK/PD/Biomarker consent
will be collected at selected 
sites.
PK/PD/Biomarker testing is 
limited to selected sites.
Section 8.1.11, Participant
Blinding/Unblinding
Added treatment unblinding 
guidance. 
Inadvertently omitted during 
original protocol creation. 
Section 8.1.13, 
PK/PD/Biomarker 
Subpopulation
Modified the text to indicate 
that enrollment for the 
PK/PD/Biomarker sampling 
will be at least 15 
participants per arm.
Refer to rationale for change 
in Section 4.1.
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Section Number and 
Name
Description of Change
Brief Rationale
Section 8.2.1, PROs
Added PROs timing and 
training information.
To harmonize with other 
sections of the protocol. 
Section 8.3.2, Vital signs
HR and BP will be assessed 
similarly.
Corrected to avoid 
confusion.
Added collection of vital 
signs timing exception.
Corrected a protocol 
inconsistency.
Section 8.3.6, TB Testing
Added TB testing guidance.
Refer for change in Section 
5.2 regarding TB testing.
Section 8.3.7, Chest X-ray
Added the focus of chest 
x-rays is to identify TB.
Added as additional 
investigator guidance. 
Section 8.10.2, Double-
Blind Treatment Period
Added clarification regarding 
PROs administration.
Refer to rationale for change 
in Section 8.2.1.
Section 10.1.1, Code of 
Conduct for Interventional 
Clinical Trials
EU regulation number was 
added. 
Added for completeness.
Section 10.1.3, Data 
Protection
Data protection guidelines 
have been updated.
To align with current 
regulatory guidance.
Section 10.2, Clinical 
Laboratory Tests
Added local TB testing to the 
footnote in the 
Protocol-required Safety 
Laboratory Assessments 
table.
TB testing will be conducted 
locally, as applicable.
Section 10.3.2, Definition 
of AE
New or progression of 
existing cancer was added to 
the list of events meeting the 
AE definition.
Refer to rationale for change 
in Section 8.1.11. 
Section 10.7.4, 
Country-specific 
Requirements for Japan
HBV description was 
updated to match the global 
study protocol.
Refer to rationale for change 
in Section 8.3.8. 
HBV-DNA testing was 
removed from Visit 2.
To eliminate redundancy. 
Section 10.4.1 definitions 
were updated.
To align with current 
country-specific guidance. 
Section 10.10, TB Risk 
Factor Assessment 
Questionnaire
Appendix 10 was added to 
help assess TB risk outlined 
in Section 8.3.6.
Refer to rationale for change 
in Section 5.2 regarding TB 
testing. 
Throughout the document
Minor administrative, 
formatting, grammatical, 
and/or typographical changes 
were made throughout the 
document.
To ensure clarity and 
accurate interpretation of the 
intent of the protocol. 
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TABLE OF CONTENTS
DOCUMENT HISTORY ........................................................................................................3
PROTOCOL AMENDMENT SUMMARY OF CHANGES...............................................4
1
PROTOCOL SUMMARY ............................................................................................16
1.1
Synopsis.................................................................................................................16
1.2
Schema ..................................................................................................................20
1.3
Schedule of Activities...........................................................................................21
1.3.1
Double-Blind Treatment Period...................................................................21
1.3.2
Blinded Extension Period ............................................................................27
1.3.3
PK/PD/Biomarker Subpopulation................................................................30
2
INTRODUCTION..........................................................................................................31
2.1
Study Rationale....................................................................................................31
2.2
Background ..........................................................................................................32
2.2.1
Pharmaceutical and Therapeutic Background .............................................33
2.2.2
Preclinical and Completed Clinical Studies.................................................33
2.2.3
Ongoing Clinical Studies.............................................................................33
2.3
Benefit/Risk Assessment......................................................................................34
3
HYPOTHESES, OBJECTIVES, AND ENDPOINTS................................................35
4
STUDY DESIGN............................................................................................................37
4.1
Overall Design......................................................................................................37
4.2
Scientific Rationale for Study Design.................................................................39
4.2.1
Rationale for Endpoints ...............................................................................39
4.2.1.1
Efficacy/QoL Endpoints ....................................................................39
4.2.1.2
Safety Endpoints................................................................................41
4.2.1.3
Pharmacokinetic Endpoints ...............................................................41
4.2.1.4
Pharmacodynamic Endpoints.............................................................41
4.2.1.5
Immunogenicity Endpoints................................................................41
4.2.1.6
Planned Exploratory Biomarker Research.........................................41
4.2.1.7
Future Biomedical Research..............................................................43
4.2.2
Rationale for the Use of Placebo .................................................................43
4.3
Justification for Dose...........................................................................................43
4.4
Beginning and End-of-Study Definition ............................................................44
4.4.1
Clinical Criteria for Early Study Termination .............................................44
5
STUDY POPULATION ................................................................................................45
5.1
Inclusion Criteria.................................................................................................45
5.2
Exclusion Criteria................................................................................................47
5.3
Lifestyle Considerations......................................................................................51
5.4
Screen Failures.....................................................................................................52
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5.5
Participant Replacement Strategy......................................................................52
6
STUDY INTERVENTION............................................................................................53
6.1
Study Intervention(s) Administered...................................................................53
6.1.1
Drug-Device Combination Products/Combination Medicinal Product .......55
6.2
Preparation/Handling/Storage/Accountability .................................................55
6.2.1
Dose Preparation..........................................................................................55
6.2.2
Handling, Storage, and Accountability........................................................55
6.3
Measures to Minimize Bias: Randomization and Blinding..............................56
6.3.1
Intervention Assignment..............................................................................56
6.3.2
Stratification.................................................................................................56
6.3.3
Blinding........................................................................................................57
6.4
Study Intervention Compliance..........................................................................57
6.5
Concomitant Therapy..........................................................................................58
6.5.1
Rescue Medications and Supportive Care ...................................................58
6.6
Dose Modification ................................................................................................58
6.6.1
Management of Serious Adverse Event of Infection...................................59
6.6.2
Management of COVID-19 Infection..........................................................59
6.6.3
Management of Eosinophilia.......................................................................59
6.7
Intervention After the End of the Study............................................................59
6.8
Clinical Supplies Disclosure................................................................................60
6.9
Standard Policies..................................................................................................60
6.9.1
Study Site Retention Samples......................................................................60
7
DISCONTINUATION OF STUDY INTERVENTION AND PARTICIPANT 
WITHDRAWAL............................................................................................................61
7.1
Discontinuation of Study Intervention...............................................................61
7.2
Participant Withdrawal From the Study...........................................................62
7.3
Lost to Follow-up .................................................................................................62
8
STUDY ASSESSMENTS AND PROCEDURES........................................................64
8.1
Administrative and General Procedures ...........................................................64
8.1.1
Informed Consent.........................................................................................64
8.1.1.1
General Informed Consent.................................................................65
8.1.1.2
Consent and Collection of Specimens for Future Biomedical 
Research.............................................................................................65
8.1.1.3
Consent for PK/PD/Biomarker Subpopulation..................................65
8.1.2
Inclusion/Exclusion Criteria ........................................................................66
8.1.3
Participant Identification Card.....................................................................66
8.1.4
Medical History ...........................................................................................66
8.1.5
Prior and Concomitant Medications Review...............................................66
8.1.5.1
Prior Medications...............................................................................66
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8.1.5.2
Concomitant Medications..................................................................67
8.1.6
Assignment of Screening Number...............................................................67
8.1.7
Assignment of Randomization Number.......................................................67
8.1.8
IRT Visit Registration, IRT Randomization, and Study Intervention 
Dispensing....................................................................................................67
8.1.9
Study Intervention Administration ..............................................................68
8.1.9.1
Timing of Dose Administration.........................................................68
8.1.9.2
Study Intervention Dispense or Return..............................................68
8.1.9.3
Train or Retrain Participant on Self-administration of Study 
Intervention........................................................................................68
8.1.9.4
Witnessed Dose..................................................................................69
8.1.9.5
Dosing Reminder ...............................................................................69
8.1.10
Discontinuation and Withdrawal .................................................................70
8.1.10.1
Withdrawal From Future Biomedical Research ................................70
8.1.10.2
Withdrawal From Additional PK/PD/Biomarker Subpopulation......70
8.1.11
Participant Blinding/Unblinding..................................................................71
8.1.12
Calibration of Equipment.............................................................................71
8.1.13
PK/PD/Biomarker Subpopulation................................................................72
8.2
Efficacy Assessments ...........................................................................................72
8.2.1
PROs ............................................................................................................72
8.2.2
ClinROs........................................................................................................73
8.2.3
Photography.................................................................................................75
8.3
Safety Assessments...............................................................................................75
8.3.1
Physical Examinations.................................................................................75
8.3.2
Vital Signs....................................................................................................76
8.3.3
Electrocardiograms ......................................................................................76
8.3.4
Clinical Safety Laboratory Assessments .....................................................76
8.3.5
Pregnancy Testing........................................................................................77
8.3.6
TB Testing ...................................................................................................77
8.3.7
Chest X-ray ..................................................................................................78
8.3.8
HBV, HCV, and HIV Testing......................................................................79
8.4
Adverse Events, Serious Adverse Events, and Other Reportable Safety 
Events....................................................................................................................80
8.4.1
Time Period and Frequency for Collecting AE, SAE, and Other 
Reportable Safety Event Information ..........................................................81
8.4.2
Method of Detecting AEs, SAEs, and Other Reportable Safety Events......83
8.4.3
Follow-up of AE, SAE, and Other Reportable Safety Event Information...83
8.4.4
Regulatory Reporting Requirements for SAE .............................................83
8.4.5
Pregnancy and Exposure During Breastfeeding ..........................................83
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8.4.6
Disease-related Events and/or Disease-related Outcomes Not Qualifying 
as AEs or SAEs............................................................................................84
8.4.7
Events of Clinical Interest............................................................................84
8.4.8
Drug-device Combination Products/Combination Medicinal Products –
Complaints, PQCs, and Malfunctions..........................................................84
8.5
Treatment of Overdose........................................................................................85
8.6
Pharmacokinetics.................................................................................................85
8.6.1
Blood Collection for Serum MK-6194 ........................................................85
8.7
Pharmacodynamics..............................................................................................85
8.7.1
Immunogenicity Assessments......................................................................86
8.7.2
Immunophenotyping....................................................................................86
8.8
Biomarkers ...........................................................................................................86
8.8.1
Planned Genetic Analysis Sample Collection..............................................86
8.9
Future Biomedical Research Sample Collection...............................................87
8.10
Visit Requirements...............................................................................................87
8.10.1
Screening/Rescreening Visits ......................................................................87
8.10.2
Double-Blind Treatment Period...................................................................88
8.10.3
Blinded Extension Period ............................................................................88
8.10.4
PK/PD/Biomarker Subpopulation Visits .....................................................88
8.10.5
Participants Discontinued From Study Intervention but Continuing to be 
Monitored in the Study ................................................................................89
8.10.6
Follow-up Telephone Call ...........................................................................89
9
KEY STATISTICAL CONSIDERATIONS ...............................................................90
9.1
Responsibility for Analyses/In-house Blinding .................................................90
9.2
Hypotheses/Estimation ........................................................................................90
9.3
Analysis Endpoints...............................................................................................90
9.3.1
Efficacy Endpoints.......................................................................................91
9.3.2
Safety Endpoints..........................................................................................91
9.4
Analysis Populations............................................................................................91
9.4.1
Efficacy Analysis Population.......................................................................91
9.4.2
Safety Analysis Population..........................................................................91
9.4.3
Pharmacokinetic Analysis Population .........................................................91
9.4.4
Pharmacodynamic Analysis Population ......................................................91
9.4.5
Immunogenicity Analysis Population..........................................................92
9.5
Statistical Methods...............................................................................................92
9.5.1
Estimand(s) ..................................................................................................92
9.5.2
Statistical Methods for Efficacy Analyses...................................................92
9.5.3
Statistical Methods for Safety Analyses ......................................................94
9.6
Interim Analyses ..................................................................................................94
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9.7
Multiplicity ...........................................................................................................95
9.8
Sample Size and Power Calculations .................................................................95
10
SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS.....................................................................................................96
10.1
Appendix 1: Regulatory, Ethical, and Study Oversight Considerations........96
10.1.1
Code of Conduct for Interventional Clinical Trials .....................................96
10.1.2
Financial Disclosure.....................................................................................99
10.1.3
Data Protection...........................................................................................100
10.1.3.1
Confidentiality of Data ....................................................................102
10.1.3.2
Confidentiality of Participant Records.............................................102
10.1.3.3
Confidentiality of IRB/IEC Information..........................................102
10.1.4
Committees Structure.................................................................................102
10.1.4.1
Executive Oversight Committee......................................................102
10.1.4.2
External Data Monitoring Committee .............................................103
10.1.5
Publication Policy......................................................................................103
10.1.6
Compliance with Study Registration and Results Posting Requirements .103
10.1.7
Compliance with Law, Audit, and Debarment ..........................................104
10.1.8
Data Quality Assurance .............................................................................104
10.1.9
Source Documents .....................................................................................105
10.1.10
Study and Site Closure...............................................................................106
10.2
Appendix 2: Clinical Laboratory Tests............................................................107
10.3
Appendix 3: Adverse Events: Definitions and Procedures for Recording, 
Evaluating, Follow-up, and Reporting.............................................................109
10.3.1
Definitions of Medication Error, Misuse, and Abuse................................109
10.3.2
Definition of AE ........................................................................................109
10.3.3
Definition of SAE ......................................................................................110
10.3.4
Additional Events Reported.......................................................................111
10.3.5
Recording AE and SAE .............................................................................111
10.3.6
Reporting of AEs, SAEs, and Other Reportable Safety Events to the 
Sponsor ......................................................................................................114
10.4
Appendix 4: Drug-Device Combination Products/ Combination 
Medicinal Products: Complaints, Product Quality 
Complaints/Malfunctions: Definitions, Recording, and Follow-up ..............116
10.4.1
Definitions..................................................................................................116
10.4.2
Recording, Assessing Causality, and Follow-up of PQCs/Malfunctions ..117
10.5
Appendix 5: Contraceptive Guidance..............................................................119
10.5.1
Definitions..................................................................................................119
10.5.2
Contraceptive Requirements......................................................................120
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10.6
Appendix 6: Collection and Management of Specimens for Future 
Biomedical Research..........................................................................................121
10.7
Appendix 7: Country-specific Requirements..................................................125
10.7.1
Country specific Requirements for Argentina ...........................................125
10.7.2
Country specific Requirements for the Czech Republic............................125
10.7.3
Country-specific Requirements for Germany............................................125
10.7.4
Country-specific Requirements for Japan..................................................126
10.7.5
Country-Specific Requirements for France ...............................................129
10.8
Appendix 8: Examples of Commonly Used Medications/Vaccines...............130
10.9
Appendix 9: Hypereosinophilic Syndrome or Eosinophil-Associated 
Organ Injury ......................................................................................................133
10.10 Appendix 10: TB Risk Factor Assessment Questionnaire .............................134
10.11 Appendix 11: Abbreviations .............................................................................135
11
REFERENCES.............................................................................................................141
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LIST OF TABLES
Table 1
Prohibited Medications................................................................................49
Table 2
Study Interventions......................................................................................54
Table 3
Reporting Periods and Time Frames for Adverse Events and Other 
Reportable Safety Events ............................................................................81
Table 4
Analysis Strategy for Key Efficacy Variables.............................................93
Table 5
Analysis Strategy for Safety Parameters......................................................94
Table 6
Protocol-required Safety Laboratory Assessments....................................108
Table 7
Commonly Used Immune Checkpoint Inhibitors......................................130
Table 8
Commonly Used Biologic Therapies.........................................................130
Table 9
Commonly Used Advanced Immunosuppressive Small Molecule 
Medications ...............................................................................................131
Table 10
Organ-Restricted (Inflammatory) Conditions Accompanied by 
Hypereosinophilia .....................................................................................133
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LIST OF FIGURES
Figure 1
Study Design................................................................................................20
Figure 2
Interpretation and Management of HBV Serologic Test Results ................80
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1
PROTOCOL SUMMARY
1.1
Synopsis
Protocol Title: A Phase 2a, Multicenter, Randomized, Double-blind, Placebo-controlled 
Study to Evaluate the Efficacy and Safety of MK-6194 in Adult Participants with Non-
Segmental Vitiligo 
Short Title: MK-6194 in Adult Participants with Non-Segmental Vitiligo
Acronym: N/A
Hypotheses, Objectives, and Endpoints:
In adult participants with non-segmented vitiligo:
Primary Objective
Primary Endpoint
To evaluate the efficacy of MK-6194 on the 
percent change from baseline in Facial 
Vitiligo Area Scoring Index (F-VASI) at 
Week 24
H1: At least 1 MK-6194 dose is superior to 
placebo on percent change from baseline in 
Facial Vitiligo Area Scoring Index 
(F-VASI) at Week 24
F-VASI
To evaluate the safety and tolerability of 
MK-6194
AEs 
Discontinuation due to AEs
Secondary Objective
Secondary Endpoint
To evaluate the efficacy of MK-6194 on the 
percent change from baseline in Total 
Vitiligo Area Scoring Index (T-VASI) at 
Week 24
T-VASI
092SJ5

PRODUCT: MK-6194
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09-APR-2024
Overall Design:
Study Phase
Phase 2
Primary Purpose
Treatment
Indication
Vitiligo
Population
Adult participants with non-segmental vitiligo
Study Type
Interventional
Intervention Model
Parallel
This is a multi site study.
Type of Control
Placebo
Study Blinding
Double-blind
Blinding Roles
Sponsor
Investigator
Participants or Subjects
Estimated Duration of Study
The Sponsor estimates that the study will require 
approximately 28 months from the time the first 
participant (or their legally acceptable 
representative) provides documented informed 
consent until the last participant’s last study-
related contact.
Participants will take part in the study for 58
weeks.
See Appendix 7 for country-specific 
requirements.
Number of Participants:
Approximately 165 participants will be randomized.
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Intervention Groups and Duration:
Arm Name
Intervention 
Name
Unit Dose 
Strength(s)
Dosage 
Level(s)
Route of 
Administration
Regimen/
Treatment 
Period/
Vaccination 
Regimen
Use
MK-6194 
Q2W
MK-6194
3 mg
3 mg
SC
Double-Blind 
Treatment and 
Blinded 
Extension 
Periods
Test Product
MK-6194 
Q4W
MK-6194
3 mg
3 mg
SC
Double-Blind 
Treatment and 
Blinded 
Extension 
Periods
Test Product
MK-6194 
Q4W
Placebo
0 mg
0 mg
SC
Double-Blind 
Treatment and 
Blinded 
Extension 
Periods
Placebo
Placebo
Q2W
Placebo
0 mg
0 mg
SC
Double-Blind 
Treatment 
Period
Placebo
SC=subcutaneous; Q2W=every 2 weeks, Q4W=every 4 weeks
Note: To maintain the blind for MK-6194 Q4W, alternating placebo will be administered between the MK-6194 doses. 
Participants randomized to the placebo arm Q2W during the Double-Blind Treatment Period will be rerandomized to MK-
6194 Q2W or MK-6194 Q4W during the Blinded Extension Period.
Other current or former name or alias for the study intervention is as follows: PT101.
Total Number of Intervention Groups/Arms
3
Duration of Participation
After a Screening period of up to 4 weeks, 
each participant will receive study
intervention for approximately 52 weeks
(24 weeks Double-Blind Treatment Period
+ 28 weeks Blinded Extension Period), 
followed by a safety follow-up telephone 
call 28 days after last study intervention is 
administered.
092SJ5

PRODUCT: MK-6194
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PROTOCOL/AMENDMENT NO.: 007-02
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Study Governance Committees:
Executive Oversight Committee
Yes
Data Monitoring Committee
Yes
Clinical Adjudication Committee
No
Study Accepts Healthy Participants: No
A list of abbreviations is in Appendix 11.
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PRODUCT: MK-6194
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1.2
Schema
The study design is depicted in Figure 1.
Figure 1
Study Design
IA= interim analysis; PBO= placebo; PK= pharmacokinetics; pts= participants; Q2W= every 2 weeks; Q4W= every 4 weeks; TC= telephone call; V= visit; Wk(s)= week(s)
092SJ5

PRODUCT: MK-6194
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09-APR-2024
1.3
Schedule of Activities
1.3.1
Double-Blind Treatment Period
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Administrative Procedures
Informed consent
X
Informed consent for FBR
X
FBR consent is 
optional
IRT visit registration
X
X
X
X
X
X
X
X
Medical history 
X
Prior/concomitant medications
X
X
X
X
X
X
X
X
X
X
X
Inclusion/exclusion criteria
X
X
Participant identification card
X
X
Add Randomization 
number to card at Visit 
2.
IRT randomization
X
Study intervention dispense/return
X
X
X
X
X
X
X
X
Dispense at Wks 2-18; 
return at all visits.
Assess compliance of 
returned syringe(s).
SC injection: train/retrain participant 
on self-administration
X
X
Self-administration is 
preferrable. Retrain as 
necessary. See Section 
8.1.9.3.
SC injection: witnessed dose
X
X
X
Study staff to ensure 
proper self-
administration. 
technique. See Section 
8.1.9.4.
092SJ5

PRODUCT: MK-6194
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PROTOCOL/AMENDMENT NO.: 007-02
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Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Participant Reminder Log:
train/dispense
X
X
X
X
X
X
For recording study 
intervention 
administration, any 
complaints/illnesses, 
and any new 
medications taken 
between study visits.
Participant Reminder Log:
review/collect
X
X
X
X
X
X
X
X
X
To be reviewed for 
accuracy. Verbal 
review at TC. See 
Section 8.1.9.5.
Dosing reminder telephone call
X
X
Additional reminders 
as necessary per site
Efficacy Procedures
PROs to be completed 
in order listed, before 
laboratory tests or other 
safety or efficacy 
procedures
VitiQoL Instrument
X
X
X
X
VNS
X
X
X
Patient Global Impression of 
Severity 
X
X
X
X
Patient Global Impression of 
Change/Meaningfulness
X
X
X
Clinical Global Impression of 
Severity
X
X
X
X
Clinical Global Impression of 
Change
X
X
X
F-VASI
X
X
X
X
X
X
X
X
X
T-VASI
X
X
X
X
X
X
X
CCI
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PRODUCT: MK-6194
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PROTOCOL/AMENDMENT NO.: 007-02
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09-APR-2024
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Other Procedures
Photography (face)
X
X
X
X
X
X
If baseline 
photographs are
sufficient, 
photographs at 
Randomization are 
not required. See 
Section 8.2.3.
Photography (total body)
X
X
X
X
X
If baseline 
photographs are 
sufficient, 
photographs at 
Randomization are 
not required. See 
Section 8.2.3.
Safety Procedures
Height
X
Weight
X
X
X
Vital signs 
X
X
X
X
X
X
X
X
X
Taken after completion 
of PROs and before 
blood samples 
collection
Full physical examination 
X
X
X
Directed physical examination
X
X
X
X
X
X
Per institutional 
standards, consistent 
with local requirements
12-lead ECG
X
Locally read
Chemistry
X
X
X
X
X
X
X
Hematology 
X
X
X
X
X
X
X
X
CCI
092SJ5

PRODUCT: MK-6194
24
PROTOCOL/AMENDMENT NO.: 007-02
MK-6194-007-02 FINAL PROTOCOL
09-APR-2024
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Urinalysis (with microscopy)
X
X
X
To be performed at 
additional visits if 
clinical symptoms 
suggestive of UTI
Serum pregnancy test (hCG; 
POCBP only)
X
FSH- (PONCBP only)
X
To confirm 
postmenopausal status. 
See Section 10.5.1.
Local urine pregnancy test (POCBP 
only)
X
X
X
X
X
X
Administered predose. 
If a urine test cannot be 
confirmed as negative 
(eg, an ambiguous 
result), serum test is 
required. See Appendix 
7 for country-specific 
requirements.
TSH
X
HIV, HBV, and HCV testing
X
See Section 8.3.8 to 
determine if further 
testing is needed. See 
Appendix 7 for 
country-specific 
requirements.
HBV-DNA testing
X
X
X
X
Only for participants 
with positive HBcAb 
and HBV-DNA 
<LLOQ at Screening.
TB testing
X
QFT TB Gold test or 
equivalent. See Section 
8.3.6 and Section 5.2 
(exclusion criterion 
#13).
092SJ5

PRODUCT: MK-6194
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PROTOCOL/AMENDMENT NO.: 007-02
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09-APR-2024
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Chest X-ray
X
Posterior-anterior chest 
x-ray. Locally read.
See Section 8.3.7.
AE/SAE review
X
X
X
X
X
X
X
X
X
X
X
PK/PD/Biomarkers (All participants)
Blood for serum ADA
X
X
X
X
X
X
Samples for ADA and 
PK should be drawn at 
the same time predose
Blood for serum PK
X
X
X
X
X
X
X
X
 
 
 
 
Blood for genetic analysis
X
Predose from 
randomized 
participants only, See 
Section 8.8.1.
Blood for DNA analysis
X
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9.
Blood for immunophenotyping
X
X
X
X
X
X
See Section 8.7.2
CCI
092SJ5

PRODUCT: MK-6194
26
PROTOCOL/AMENDMENT NO.: 007-02
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09-APR-2024
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1
Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week:
Up to 
4 wks
Day 1 
Wk 0
Day 2
Wk 2
Wk 4
Wk 6
Wk 8
Wk 12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 24
Day
1
2
15
29
43
57
85
86
127
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Blood for serum biomarkers analysis
X
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9.
Blood for RNA analysis
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9.
ADA= antidrug antibodies; AE= adverse event(s); d= day; Discon= discontinuation; DNA= deoxyribonucleic acid; EC=Ethics Committee; ECG= electrocardiogram; FBR= 
Future Biomedical Research; FSH= follicle-stimulating hormone; F-VASI= Facial Vitiligo Area Scoring Index; h= hour; HBcAb= hepatitis B core antibody; HBV= hepatitis B 
virus; HCV= hepatitis C virus; hCG= human chorionic gonadotropin; HIV= human immunodeficiency virus; IRB= Institutional Review Board; IRT= interactive response 
technology; LLOQ= lowest limit of quantitation; PD= pharmacodynamics; PK= pharmacokinetics; POCBP= Participant of childbearing potential; PONCBP= Participant of 
nonchildbearing potential; PROs=participant reported outcomes; Q2W= every 2 weeks; QFT= QuantiFERON; QoL= quality of life; Rand= randomization; RNA= ribonucleic 
acid; SAE= serious adverse event(s); SC= subcutaneous; TB= tuberculosis; TC= telephone call; TSH= thyroid-stimulating hormone; T-VASI= Total Vitiligo Area Scoring Index; 
UTI= urinary tract infection; V=visit; 
; VitiQoL= Vitiligo Quality of Life Instrument; VNS= Vitiligo Noticeability Scale; Wk(s)= 
Week(s).
(a) Procedures for the Blinded Extension portion of this visit are in Section 1.3.2.
CCI
092SJ5

PRODUCT: MK-6194
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09-APR-2024
1.3.2
Blinded Extension Period
Study Period:
Blinded Extension Period
Notes
Visit Number/Title:
10a
11
12
13
14
15
TC
16
Discon
F/U
TC
Scheduled Day/Week
Wk 
24
Wk 
26
Wk 
28
Wk 
32
Wk 
36
Wk 
44
Wk 
48
Wk
52
28 Days 
After Last 
Dose
Day
169
183
197
225
253
309
337
365
Recommended Window:
±7d
±3d
±3d
±7d
±7d
±7d
±3d
±7d
+7d
Administrative Procedures
Prior/concomitant medication 
X
X
X
X
X
X
X
X
X
IRT visit registration
X
X
X
X
X
X
X
X
IRT rerandomization
X
Collect participant identification 
card from the Double-Blind 
Treatment Period
X
New participant identification 
card
X
Add rerandomization number to card at Visit 10. 
See Section 8.1.3.
Study intervention 
dispense/return 
X
X
X
X
X
X
X
X
Assess compliance of returned syringe(s). Dispense 
at Wks 24 to 44; return at all visits.
Participant Reminder Log: 
train/dispense
X
X
X
X
X
X
For recording study intervention administration, 
any complaints/illnesses, and any new medications 
taken between study visits
Participant Reminder Log: 
review/collect
X
X
X
X
X
X
X
X
To be reviewed for accuracy. Verbal review at TC. 
See Section 8.1.9.5.
Dosing reminder telephone call
X
Last dose to be administered at Wk 50. Additional 
reminders as necessary per site.
Efficacy Procedures
PROs to be completed in order listed, before 
laboratory tests or other safety or efficacy 
procedures
VitiQoL Instrument
X
X
X
VNS
X
X
X
Patient Global Impression of 
Severity
X
X
X
Patient Global Impression of 
Change/Meaningfulness
X
X
X
Clinical Global Impression of 
Severity
X
X
X
Clinical Global Impression of 
Change
X
X
X
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PRODUCT: MK-6194
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Study Period:
Blinded Extension Period
Notes
Visit Number/Title:
10a
11
12
13
14
15
TC
16
Discon
F/U
TC
Scheduled Day/Week
Wk 
24
Wk 
26
Wk 
28
Wk 
32
Wk 
36
Wk 
44
Wk 
48
Wk
52
28 Days 
After Last 
Dose
Day
169
183
197
225
253
309
337
365
Recommended Window:
±7d
±3d
±3d
±7d
±7d
±7d
±3d
±7d
+7d
F-VASI
X
X
X
X
X
X
T-VASI
X
X
X
Other Procedures
Photography (face)
X
X
X
Photography (total body)
X
X
X
Safety Procedures
Weight
X
X
Vital signs 
X
X
X
X
X
X
X
Taken after completion of PROs and before blood 
samples collection
Full physical examination
X
X
Directed physical examination
X
X
X
X
X
Per institutional standards, consistent with local 
requirements.
Chemistry
X
X
X
X
X
X
Hematology
X
X
X
X
X
X
X
Urinalysis (with microscopy)
X
X
To be performed at additional visits if clinical 
symptoms suggestive of UTI.
Local urine pregnancy test 
(POCBP only)
X
X
X
X
X
X
Administered predose. If urine test not confirmed 
as negative (eg, ambiguous result), serum test is
required. See Appendix 7 for country-specific 
requirements.
HBV-DNA testing
X
X
X
Only for participants with positive HBcAb and 
HBV-DNA <LLOQ at Screening.
AE/SAE review
X
X
X
X
X
X
X
X
X
PK/PD/Biomarkers (All participants)
Blood for serum ADA
X
X
Samples for ADA and PK should be drawn at same 
time predose
Blood for serum PK
X
X
Samples for ADA and PK should be drawn at same 
time predose
Blood for DNA analysis
X
X
Leftover sample will be stored for FBR. See 
Section 8.9.
CCI
CCI
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PRODUCT: MK-6194
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09-APR-2024
Study Period:
Blinded Extension Period
Notes
Visit Number/Title:
10a
11
12
13
14
15
TC
16
Discon
F/U
TC
Scheduled Day/Week
Wk 
24
Wk 
26
Wk 
28
Wk 
32
Wk 
36
Wk 
44
Wk 
48
Wk
52
28 Days 
After Last 
Dose
Day
169
183
197
225
253
309
337
365
Recommended Window:
±7d
±3d
±3d
±7d
±7d
±7d
±3d
±7d
+7d
Blood for immunophenotyping
X
X
See Section 8.7.2
Blood for serum biomarkers 
analysis
X
X
Leftover sample will be stored for FBR. See 
Section 8.9.
Blood for RNA analysis
X
X
Leftover sample will be stored for FBR. See 
Section 8.9.
ADA= antidrug antibodies; AE= adverse event(s); d= day; Discon= discontinuation; DNA= deoxyribonucleic acid; FBR= future biomedical research; F/U= follow-up; 
F-VASI= Facial Vitiligo Area Scoring Index; HBcAb= hepatitis B core antibody; HBV= hepatitis B virus; IRT= interactive response technology; LLOQ= lower limit of 
quantitation; PD= pharmacodynamics; PK= pharmacokinetics; POCBP= Participant of childbearing potential; Q2W= every 2 weeks; QoL= quality of life; RNA= ribonucleic 
acid; SAE= serious adverse event(s); SC= subcutaneous; TC= telephone call; TSH= thyroid-stimulating hormone; T-VASI= Total Vitiligo Area Scoring Index; UTI= urinary 
tract infection; 
 VitiQoL= Vitiligo Quality of Life Instrument; VNS= Vitiligo Noticeability Scale; Wk= Week.
(a) Procedures for the Double-Blind portion of this visit are in Section 1.3.1 and should be completed before Blinded Extension procedures
CCI
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PRODUCT: MK-6194
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1.3.3
PK/PD/Biomarker Subpopulation
Study Period:
PK/PD/Biomarker Additional Samplesa,
Notes
Visit Number/Title:
1
2
Rand
3A
5
7
8A
9A
10
15A
16
Discon
Scheduled Day/Week:
Day 1
Wk0
Day 8
Wk 1
Wk 4
Wk 12
Wk 13
Wk 21
Wk 24
Wk 49
Wk 52
7 Days 
post 
Day 1 
dose
7 Days 
post 
Wk 12 
dose
7 Days 
post 
Wk 20 
dose
7 Days 
post 
Wk 48 
dose
Day
1
8
29
85
92
148
169
344
365
Recommended Window:
±1d
±1d
±1d
±1d
Informed consent for 
additional PK/PD/Biomarker
samples in Subpopulation
X
Hematology
X
X
X
X
Blood for PBMC
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9
Blood for serum PK
X*
X
X*
X
X
X
*Visit 2 or 7: 2h to 10h 
post dose. See Section 
8.10.4 for details
Blood for DNA analysis
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9.
Blood for 
immunophenotyping
X
X
X
X
X
X
X
X
X
X
See Section 8.7.2
Blood for serum biomarkers 
analysis
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9
Blood for RNA analysis
X
X
X
X
Leftover sample will be 
stored for FBR. See 
Section 8.9
d= day; Discon= discontinuation; DNA= deoxyribonucleic acid; FBR= future biomedical research; PBMC= peripheral blood mononuclear cells; PD= pharmacodynamics; PK= 
pharmacokinetics; Rand= randomization; RNA= ribonucleic acid; Wk= Week.
a For participants at preselected sites (determined by operational feasibility of site for sample processing) who consent for additional PK/PD/Biomarker samples (ie, the 
Subpopulation) in addition to the activities listed in the Treatment and Extension Period Schedule of Activities (Sections 1.3.1 and 1.3.2) for all study participants.
092SJ5

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2
INTRODUCTION
2.1
Study Rationale
Human autoimmune disease results, in part, from dysfunctional or insufficient numbers of 
Tregs that cause organ damage by not properly restricting immune responses [Kolios, A. G. 
A., et al 2021]. MK-6194 is a novel IL-2M that selectively expands regulatory T cells, 
without activating cytotoxic immune cell counterparts. This mechanism offers a unique 
opportunity to rebalance the dysregulated immune responses of patients with a wide range of 
autoimmune disease.
Vitiligo is an acquired chronic inflammatory skin depigmenting disorder resulting from 
selective destruction of melanocytes. This destruction leads to the development of typical 
vitiligo lesions defined as milky white, nonscaly macules with distinct margins. Progressive 
patchy loss of pigmentation from skin, overlying hair, and sometimes mucosa remains the 
basis of a diagnosis of vitiligo [Ezzedine, K., et al 2015].
Vitiligo is a common disease with a worldwide reported prevalence of 0.5 to 1 % overall, but
with rates eg, as high as 8.8% in India. The difference of prevalence is not fully understood 
and might in part be due to differences in reporting frequency. It is by far the most common 
depigmenting disease. Adults and children of both sexes are equally affected, although 
women and girls often present for treatment more frequently [Ezzedine, K., et al 2015].
Vitiligo can be classified into 2 major forms, segmental and non-segmental vitiligo. The non-
segmental form is the most common and will be studied in this trial. Non-segmental vitiligo 
develops at all ages, approximately 50% of patients present before the age of 20 and almost 
70 to 80% before the age of 30, although it can also develop beyond the age of 40.
Childhood-onset vitiligo (before age 12 years) is reported to be common and can affect more 
than 30% of patients. The course of the disease is unpredictable and phases of almost no 
progression can be followed by more active phases. In addition to new or extending lesions,
other indicators of areas of higher disease activity are clinically assessable and include 
Koebner’s phenomenon, trichrome lesions, confetti lesions, and inflammatory vitiligo 
lesions. The treatment trajectory depending on the activity status a patient is in might change
the outcome, so it is important to assess and distinguish [Ezzedine, K., et al 2015].
While vitiligo has no impact on life expectancy, due to the nature of the color dissimilarity it 
has a great impact on the psychosocial aspect of affected patients’ life and mental well-being. 
The unpredictability of the disease in the form of sudden new and enlarged lesions creates 
additional stress from this disease to the patient [Ezzedine, K., et al 2015].
The associated stigma results in a higher rate of psychiatric comorbidities[Ezzedine, K., et al 
2015].
Currently there is only one FDA-approved treatment available, which is a topical JAKi, and
it showed significant repigmentation when applied twice daily to up to 10% of the body 
surface [Rosmarin, D., et al 2022]. Other treatments include steroids, systemic and topical as 
well as calcineurin inhibitors, and phototherapy [Ezzedine, K., et al 2015]. All available 
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treatment options come either with a serious warning in their label, including a black box 
warning in the US for JAKi and/or a high patient burden so there remains a high unmet need 
for safe and tolerable treatment options [U.S. Prescribing Information 2023].
The pathophysiology of vitiligo is complex, but has not yet been fully understood and it 
involves multiple factors [Ezzedine, K., et al 2015].
Various theories have been suggested for the cause of melanocyte loss in vitiligo, with the 
autoimmune hypothesis having the strongest evidence. This includes the clinical association 
of vitiligo with other autoimmune disorders, such as autoimmune thyroid disease, type 1 
diabetes, pernicious anemia, rheumatoid arthritis, systemic lupus erythematosus, and 
Addison disease as well as atopic background. These findings are consistently reported 
although the frequency varies[Alkhateeb, A., et al 2003].
A shared underlying genetic susceptibility to autoimmune diseases has been suggested as an 
increased frequency of autoimmune diseases have been reported in relatives of vitiligo 
patients.
Several studies in animals support the role of the innate immune response. An overactive 
so-called danger signaling cascade in vitiligo lesions has been shown and melanocytes from 
patients with vitiligo have proved more susceptible to oxidative stress than those from 
unaffected individuals and more difficult to culture ex vivo than those from healthy controls.
In response to stressors, reactive oxygen species are released from melanocytes. This 
ultimately leads to the activation of innate immune cells (eg, natural killer cells and 
inflammatory dendritic cells). Reactive oxygen species can also initiate a signaling cascade 
through unfolded protein response activation. Induction of the unfolded protein response can 
result in the direct release of proinflammatory cytokines (interleukins 6 and 8) from 
melanocytes, which can antagonize the suppressor function of regulatory T cells [Ezzedine, 
K., et al 2015] [Seneschal, J., et al 2021].
The role of CD4+ T cells in the pathogenesis of the disease is still unclear, a possible role of 
dysregulated regulatory T cells has been suggested [Lili, Y., et al 2012] [Zhou, L., et al 
2012]. GWAS identified a polymorphism of FOXP3, the master transcription factor of Tregs, 
in vitiliginous skin [Shen, C., et al 2016] as well as involvement of genes encoding IL2RA 
[Jin, Y., et al 2010] [Shen, C., et al 2016]. Additional data from skin lesions is suggesting an 
increased skin expression of CCL22 responsible for inducing the migration of Tregs into the 
skin. [Eby, J. M., et al 2015] Selective mouse models of depigmentation further suggests a 
role of regulatory Tregs by demonstrating FOXP3+CD3+cells were 2.6-fold more frequent in 
repigmented than depigmented areas [Eby, J. M., et al 2014].
The selective activation of Tregs is therefore a potential approach for improving vitiligo.
The primary objective of this study is to characterize the efficacy and safety of MK-6194 
among participants with non-segmental vitiligo.
2.2
Background
Refer to the IB for detailed background information on MK-6194.
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2.2.1
Pharmaceutical and Therapeutic Background
Autoimmune and inflammatory diseases result from disrupted immune homeostasis and 
inappropriate immune activity, often driven by Teff. Tregs attenuate inflammatory processes 
by a variety of mechanisms that suppress the activity of Teff [Klatzmann, D. and Abbas, A. 
K. 2015]. Expansion of Tregs using repeated administration of low doses of IL-2 has shown 
preliminary evidence of clinical efficacy in small proof-of-concept studies in participants 
with a variety of autoimmune diseases [Castela, E., et al 2014] [Hartemann, A., et al 2013] 
[He, J., et al 2016] [Koreth, J., et al 2011] [Rosenzwajg, M., et al 2015] [Rosenzwajg, M., et 
al 2019] [Saadoun, D., et al 2011].
MK-6194 is a recombinant IL-2M fused at its C-terminus to the N-terminus of an effector 
function ablated human IgG1 Fc domain. Compared with wild-type human IL-2, the 
modified IL-2M component of MK-6194 contains mutations that increase the binding 
affinity for the IL-2Rα subunit (CD25) and reduce the binding affinity for the IL-2Rβ subunit 
(CD122). Collectively, these mutations lead to MK-6194 selectively activating Tregs over 
other cell types, including Tconv and NK cells.
2.2.2
Preclinical and Completed Clinical Studies
After a single-dose administration of MK-6194 to healthy adults, the geometric mean 
half-life of MK-6194 ranged from 20.4 to 28.3 hours, and the geometric mean Tmax was 
10.5 to 13.5 hours. MK-6194 exposure was generally dose-proportional. There was no 
evidence of induction of pharmacologically or clinically relevant ADA to MK-6194 after a 
single administration.
Refer to the IB for detailed preclinical and clinical information on MK-6194.
2.2.3
Ongoing Clinical Studies
The current ongoing clinical studies in the MK-6194 development program include 5 Phase 1 
studies, a MAD study in participants with ulcerative colitis (P002), a MAD study in healthy 
participants (P003), a single-dose study in healthy Japanese participants (P004), a MAD trial 
in participants with atopic dermatitis (P008), and a study to evaluate the impact of injection 
site on PK and relative bioavailability in healthy participants (P013).
Preliminary blinded safety data from these studies indicate that MK-6194 has been generally 
well tolerated to date.
Refer to the IB for more information on MK-6194.
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2.3
Benefit/Risk Assessment
It cannot be guaranteed that participants in clinical studies will directly benefit from study
participation, as clinical studies are designed to provide information about the safety and 
efficacy of an investigational medicine.
MK-6194 administered subcutaneously appears to be generally well tolerated in the 
completed and ongoing Phase 1 clinical studies at single doses 
 
. The number of participants exposed to multiple doses of MK-6194 over several 
weeks is continuously increasing due to the ongoing clinical development across several 
indications. The most frequently reported AEs are cutaneous AEs, including injection-site 
reactions, and elevated absolute eosinophil count. The cutaneous AEs were generally mild or 
moderate in intensity, self-limited, and did not require medical therapy. Transient mild to 
moderate increased absolute eosinophil counts have been observed in some participants who 
received MK-6194, which returned to normal range or were trending toward normal by the 
end of the treatment. There have been no events of eosinophil-associated organ injury. 
Injection-site reactions and increased eosinophil counts have been previously reported in 
patients receiving recombinant IL-2, including low-dose IL-2, for the treatment of 
autoimmune diseases [Fanton, C., et al 2020] [Van Gool, F., et al 2014] [Rosenzwajg, M., et 
al 2019].
The benefit/risk assessment for MK-6194 is considered favorable for its evaluation as a 
potential treatment for the treatment of vitiligo.
Additional details are provided in the IB and informed consent documents.
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3
HYPOTHESES, OBJECTIVES, AND ENDPOINTS
In adult participants with non-segmented vitiligo:
Primary Objective
Primary Endpoint
To evaluate the efficacy of MK-6194 on 
the percent change from baseline in Facial 
Vitiligo Area Scoring Index (F-VASI) at 
Week 24
H1: At least 1 MK-6194 dose is superior to 
placebo on percent change from baseline in 
Facial Vitiligo Area Scoring Index 
(F-VASI) at Week 24
F-VASI
To evaluate the safety and tolerability of 
MK-6194
AEs 
Discontinuation due to AEs
Secondary Objectives
Secondary Endpoints
To evaluate the efficacy of MK-6194 on 
the percent change from baseline in Total 
Vitiligo Area Scoring Index (T-VASI) at 
Week 24
T-VASI
Tertiary/Exploratory Objectives
Tertiary/Exploratory Endpoints
To evaluate the efficacy of MK-6194 on 
the proportion of participants achieving 
50%, 75%, and 90% improvement in F-
VASI response at Week 24
F-VASI-50, F-VASI-75, F-VASI-90
To evaluate the efficacy of MK-6194 on 
the proportion of participants achieving 
50%, 75%, and 90% improvement in T-
VASI response at Week 24
T-VASI-50, T-VASI-75, T-VASI-90
To evaluate the efficacy of MK-6194 on 
the F-VASI score at all timepoints assessed 
and the proportion of participants 
achieving 25%, 50%, 75%, 90% 
improvement in F-VASI response at all 
timepoints assessed
F-VASI
F-VASI-25/50/75/90
To evaluate the efficacy of MK-6194 on 
the T-VASI score at all timepoints assessed 
and the proportion of participants 
achieving 25%, 50%, 75%, 90% 
improvement in T-VASI response at all 
timepoints assessed
T-VASI
T-VASI-25/50/75/90
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To evaluate the efficacy of MK-6194 on 
investigator’s assessment of severity and 
change in vitiligo at all timepoints assessed
CGI-S
CGI-C
To evaluate the effect of MK-6194 on 
participant’s quality of life and 
noticeability of vitiligo at all timepoints 
assessed
VitiQoL
VNS
To evaluate the efficacy of MK-6194 on 
participant’s assessment of severity and 
change in vitiligo at all timepoints assessed
PGI-S
PGIC/M
To evaluate the PK of MK-6194 at 1 day 
post first dose and Week 12 dose (Cmax) 
and at Weeks 2, 4, 12, 24, and end of study 
(Ctrough)
MK-6194 serum PK
To evaluate the PK of MK-6194 at 7 days 
post Weeks 0, 12, 20 and 48 in a subset of 
study participants
MK-6194 serum PK
To evaluate the immunogenicity of 
MK-6194 at predose and Weeks 2, 4, 12, 
24, and end of study
ADA in serum (incidence and magnitude)
To evaluate the effect of MK-6194 
on Tregs
Immunophenotyping of Tregs and other 
peripheral immune cells
To identify molecular biomarkers that may 
be indicative of clinical response, 
resistance, PD activity, and/or the 
mechanism of action of MK-6194
Blood-derived biomarker parameters that 
may include, but are not limited to DNA, 
RNA, and protein-based analyses
To explore the relationship between 
genetic variation and response to the 
treatments administered, and mechanism of 
disease. Variation across the human 
genome may be analyzed for association 
with clinical data collected in this study
Germline genetic variation and association to 
clinical data collected in this study
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4
STUDY DESIGN
4.1
Overall Design
This is a multicenter randomized, placebo-controlled, parallel-group, double-blind, study of 
MK-6194 in adult participants with non-segmental vitiligo. This study is designed to evaluate 
the efficacy and safety of MK-6194 3 mg administered subcutaneously Q2W and 3 mg 
administered subcutaneously Q4W.
This study has 3 periods, Screening, Double-Blind Treatment, and Blinded Extension.
During the screening period of up to 4 weeks, participants will be assessed for eligibility 
against the inclusion and exclusion criteria (see Section 8).
As it is unknown whether exposure to JAK inhibitors may affect response to an IL-2M, up to 
approximately 50% of participants study wide with prior JAKi exposure (topical and/or 
systemic) may be randomized after the appropriate washout period if either of the following 
criteria are met:

Response to previous treatment with a JAKi after an appropriate treatment duration 
(ie, ≥12 weeks)

History of previous JAKi use for <12 weeks regardless of response status
Note: Response is defined by the investigator, or assessed in a previous interaction with a 
qualified physician/ dermatologist; participants in which previous exposure to JAKi for 
≥12 weeks resulted in treatment failure will be excluded.
The study will also be stratified by whether participants have a history of previous JAKi use 
(yes, no) regardless of response and according to stable vs. active non-segmental vitiligo at 
Randomization (Section 6.3.2).
During the Double-Blind Treatment Period (starting at Visit 2), approximately 
165 participants will be randomized in a 1:1:1 ratio and stratified (Section 6.3.2) to receive 
either MK-6194 3 mg Q2W, 3 mg Q4W, or placebo 2QW. Participants will take part in the 
Double-Blind Treatment Period of the study for approximately 24 weeks unless the 
participant withdraws from the study (Section 7.2). To maintain the blind, all participants 
will self-administer study intervention Q2W. Participants in the MK-6194 3-mg Q4W group 
will alternate between placebo and MK-6194 Q2W in a blinded manner (Section 8.1.9.1).
Those participants who complete 24 weeks of treatment in the Double-Blind Treatment 
Period on study intervention will then enter the Blinded Extension Period. Participants 
randomized to receive MK-6194 in the Double-Blind Treatment Period will continue on the 
same MK-6194 regimen in the Blinded Extension Period. Participants randomized to receive 
placebo in the Double-Blind Treatment Period will be rerandomized to receive either 
MK-6194 3 mg Q2W or 3 mg Q4W in the Blinded Extension Period.
The Blinded Extension Period will begin at Week 24 and will last approximately 28 weeks
unless the participant withdraws from the study (Section 7.2). Participants will receive either 
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MK-6194 3 mg Q2W or MK-6194 3 mg Q4W during the Blinded Extension Period.
Participants will receive the last dose of study intervention at ~Week 50, followed by an on-
site visit at approximately 2 weeks later (Week 52 – no study intervention administered), and 
a follow-up safety phone call at approximately 28 days after the last dose of study 
intervention.
At Visit 2, study sites will train participants/caregivers to subcutaneously self-administer 
study intervention using a prefilled syringe (see Appendix 7 for country-specific 
requirements). Study site visits will take place every 2 weeks (±3 days) for the first month of 
the Double-Blind and Blinded Extension Periods, followed by visits every 4 to 8 weeks (±7 
days) until the end of the period. In addition, a visit to collect PK samples the day after 
Randomization and the day after the Week 12 study site visit will occur. When a study site 
visit is scheduled, self-administration of study intervention should take place at the study site
if possible. Participants will subcutaneously self-administer study intervention away from the 
clinic between study visits (Section 8.1.9).
An eDMC (Section 10.1.4.2) will be used during the study to periodically monitor unblinded 
safety data as well as to review results from a planned futility IA (Section 9.6) and the 
Week 24 primary endpoint analysis. The IA will be performed when approximately 50% of 
randomized participants complete Week 24 or discontinue before Week 24. If futility criteria 
are met at the IA in both treatment arms, the study will stop early. If futility criteria are met 
for one treatment arm, participants who complete the double-blind portion of the study, but
have not started the Blinded Extension, will be switched to the nonfutile arm for the 
extension period. If the study is not stopped for futility, the study will continue until all 
participants complete the safety follow-up telephone call after the last dose of study 
intervention in the Blinded Extension or discontinue. The interim analysis for futility may not 
take place if the timing of the IA falls too close to the Final Analysis of the primary endpoint. 
A full description of the eDMC responsibilities will be provided in the eDMC Charter.
PK and PD sampling will be taken for all participants during the study. The Sponsor will 
provide continuous medical monitoring of AEs, laboratory results, and adherence to the study 
protocol during the study.
Concomitant therapy is described in Section 6.5 and Section 5.2 (Table 1).
Supplemental PK/PD/Biomarker sparse sampling will be collected in a subset of participants 
at preselected sites (>15 participants per arm) to provide additional PK and PD 
measurements, allowing a more comprehensive characterization of the PK-PD relationship of 
MK-6194 (Sections 4.2.1.3 and 4.2.1.4). Additional PD and biomarker samples will be 
collected to enable Treg and other biomarker assessments at more timepoints, to allow better
understanding of PD and biomarker responses to MK-6194 in participants with vitiligo.
Specific procedures to be performed during the study, including prescribed times and 
associated visit windows, are outlined in Section 1.3 of the SoA. Details of each procedure 
are provided in Section 8.
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4.2
Scientific Rationale for Study Design
This Phase 2a study will evaluate the efficacy, safety, and tolerability of MK-6194 in the 
treatment of non-segmental vitiligo. The study will test the hypothesis that at least one dose 
of MK-6194 is superior to placebo in the primary endpoint of percent change from baseline 
in F-VASI score at Week 24.
This study will use a double-blind, placebo-controlled, parallel-group design in the 
assessment of MK-6194 to minimize potential bias and improve reliability of the results. 
Eligibility criteria for this study will support enrollment of participants with a clinical 
diagnosis of non-segmental vitiligo with disease duration of at least 6 months before
screening.
The primary efficacy endpoint will be assessed at Week 24 to allow for a reasonably 
sufficient duration to reliably assess the efficacy and safety of MK-6194 3 mg administered
Q2W and Q4W. This duration is considered appropriate to capture the primary endpoint, 
F-VASI. A Blinded Extension Period is included to allow for collection of additional efficacy 
and safety data in the participants originally randomized to the placebo group during the 
Double-Blind Treatment Period, as well as additional efficacy and safety data with longer 
treatment in the participants originally randomized to MK-6194. The study duration is
consistent with other recent treatment studies in vitiligo.
4.2.1
Rationale for Endpoints
4.2.1.1
Efficacy/QoL Endpoints
F-VASI and T-VASI
The VASI is a validated scoring method that assesses the extent and severity of areas of 
vitiligo depigmentation [Hamzavi, I., et al 2004]. Two VASI scores will be calculated; the F-
VASI to indicate facial lesions, and the T-VASI to indicate vitiligo affecting the total body, 
including the face. The primary efficacy endpoint for this study is based on the F-VASI given 
the importance of the face to patients’ well-being. The F-VASI will also be used to measure
several exploratory endpoints for various levels of improvement in vitiligo lesions on the 
face.
Changes in T-VASI will comprise a key secondary endpoint as well as several exploratory
endpoints measuring for various levels of improvement in vitiligo lesions on the body.
ClinROs
Clinical Global Impression of Change and Clinical Global Impression of Severity
The following global assessments will be performed in this study to assess impact of 
treatment intervention from the investigator’s perspective: 1) Clinical Global Impression of 
Change (CGI-C), and 2) Clinical Global Impression of Severity (CGI-S). Both of these 
assessments range from “none” to “very severe” for severity and “much better” to “much 
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worse” for change. The assessment of severity and change in vitiligo at several timepoints 
are exploratory endpoints.
PROs
VitiQoL Instrument
The VitiQoL is a 16-item validated, disease-specific instrument that measures the impact of 
vitiligo on patients’ social, emotional and physical functioning [Batchelor, J. M., et al 2016]. 
Items are scored using a 7-point Likert scale (0 – 6), with lower scores indicating better 
HRQL. The VitiQoL includes items from the Dermatology Life Quality Index (DLQI), 
Skindex-16, and adapted items from the Brief Fear of Negative Evaluation scale (BFNE), as 
well as several de novo items.
Vitiligo Noticeability Scale
The VNS is the participant’s assessment of how ‘noticeable’ vitiligo patches are after 
treatment. The noticeability of vitiligo after treatment is an important indicator of treatment 
success from a patient’s perspective [Lilly, E., et al 2013]. The VNS is a single-item measure 
that asks patients to rate the noticeability of their vitiligo compared with before they started 
treatment on a 5-point scale ranging from 1 (more noticeable) to 5 (no longer noticeable). 
Scores of 4 – 5 are considered indicative of treatment success.
Both the VitiQoL and the VNS measure exploratory endpoints and will be assessed at several 
timepoints.
PGI-S and PGIC/M
The following global assessments will be performed in this study to assess impact of 
treatment intervention from the participant’s perspective: 1) Patient Global Impression of 
Change/Meaningfulness (PGIC/M), and 2) Patient Global Impression of Severity (PGI-S). 
Both of these assessments range from “none” to “very severe” for severity and “much better” 
to “much worse” for change. The assessment of severity and change in vitiligo at several 
timepoints are exploratory endpoints. The PGIC/M also includes 2 follow-up questions for 
patients who respond that their vitiligo is either “a little better” or “much better”, or “a little 
worse” or “much worse”. The follow-up question (dependent on the response) asks if this 
change is important to the patient (Yes/No).
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4.2.1.2
Safety Endpoints
General safety and tolerability will be evaluated by clinical review of all relevant parameters, 
including AEs, vital signs, and laboratory safety tests (hematology, chemistry, and 
urinalysis), performed per the SoA (Section 1.3). AEs will be evaluated and assessed 
according to the guidelines in Section 8.4. Participants may be asked to return for 
unscheduled visits to perform additional safety monitoring.
In MK-6194 studies, absolute eosinophil counts will be measured at baseline and monitored 
during treatment. Participant discontinuation criteria related to clinically significant elevated 
eosinophil counts and/or evidence of eosinophil-related organ injury have been implemented
(Section 7.1).
4.2.1.3
Pharmacokinetic Endpoints
PK samples will be collected from all participants at select visits as described in the SoA 
(Sections 1.3.1 and 1.3.2). On dosing days, PK samples will be collected before 
administration of study intervention. At selected timepoints PK samples post dosing will also 
be collected from all participants. At selected sites, additional PK/PD/Biomarker samples 
will be collected in >15 participants per treatment arm (Section 1.3.3). PK samples will be 
used to evaluate MK-6194 serum concentrations and for exposure response models to 
evaluate PK/PD and PK/AE relationships, as appropriate. The pharmacometric analyses will 
be reported separately.
4.2.1.4
Pharmacodynamic Endpoints
Whole blood samples will be collected from all participants for Treg assessment as described 
in the SoA (Sections 1.3.1 and 1.3.2). At selected sites, additional PK/PD/Biomarker samples 
will be collected in >15 participants per treatment arm (Section 1.3.3), allowing more 
frequent PD sample collection during the study. Whole blood PD samples will be used for 
immunophenotypic analyses to evaluate MK-6194 pharmacodynamic effect under multiple 
dosing conditions.
4.2.1.5
Immunogenicity Endpoints
Immunogenicity to MK-6194 will be described as per the results of the ADA assay from 
samples taken during the treatment period as described in the SoA (Section 1.3). ADA 
samples will be collected from all participants before the administration of study intervention
at select visits. The incidence, magnitude (titer), and characterization of ADA positive 
participants and potential effects of ADA on PK, PD, and safety will be reported as 
appropriate.
4.2.1.6
Planned Exploratory Biomarker Research
The mechanism of action of many new therapeutics is not completely understood and much 
remains to be learned regarding how best to leverage new drugs in treating participants. 
Thus, to aid future participants, it is important to investigate the determinants of response or 
resistance to the treatments administered, as well as determinants of AEs during our clinical 
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studies. These efforts may identify novel predictive/pharmacodynamic biomarkers and 
generate information that may better guide single-agent and combination therapies. To 
identify novel biomarkers, biospecimens (eg, blood components, tissue material) will be 
collected to support analyses of cellular components (eg, protein, DNA, RNA, metabolites) 
and other circulating molecules. Investigations may include, but are not limited to:
Germline (blood) genetic analyses (eg, SNP analyses, whole exome sequencing, whole 
genome sequencing)
This research may evaluate whether genetic variation within a clinical study population 
correlates with response to the treatment(s) under evaluation. Genome and exome wide 
approaches may be used for this effort. In addition, epigenetic characterization techniques 
(ie, DNA methylation status, histone profiling) may also be explored. If genetic and/or 
epigenetic variation is found to predict efficacy or AEs, the data might inform optimal use of 
therapies in the patient population.
Blood/Tissue RNA analyses
Both genome-wide and targeted mRNA expression profiling and sequencing in tissue and/or 
in blood may be performed to define gene signatures that correlate to clinical response to 
treatment with therapies. Specific gene sets (eg, those capturing interferon-gamma 
transcriptional pathways) may be evaluated and new signatures may be identified. Individual 
genes may also be evaluated (eg, IL-10). MicroRNA profiling may also be pursued as well as 
exosomal profiling.
Blood/Tissue Protein biomarker analyses
Tissue and/or blood samples from this study may undergo protein-based biomarker analyses 
using a variety of platforms that could include, but are not limited to; immunoassays (eg, 
ELISA) liquid chromatography/mass spectrometry, cytometry, and immunohistochemistry. 
These approaches may be used to quantify soluble, cell- and/or tissue-based analytes to 
further elucidate therapy mechanism of action and/or assess disease-related parameters. For 
immunohistochemical analyses information on spatial context and cellular distribution may 
also be included. Correlation of protein expression to response to therapy may be performed 
to identify novel predictive biomarkers that could aid in participant selection for therapy. 
This research would serve to develop such assays for future clinical use. 
4.2.1.6.1
Planned Genetic Analysis
Genetic variation may impact a participant’s response to therapy, susceptibility to, severity, 
and progression of disease. Variable response to therapy may be due to genetic determinants 
that impact drug ADME, mechanism of action of the drug, disease etiology, and/or molecular 
subtype of the disease being treated. Therefore, where local regulations and IRB/IEC allow, a 
sample will be collected for DNA analysis from consenting participants.
DNA samples may be used for research related to the study intervention(s), the disease under 
study, or related diseases. They may also be used to develop tests/assays including diagnostic 
tests related to the disease under study, related diseases, and study intervention(s). Genetic 
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research may consist of the analysis of 1 or more candidate genes, the analysis of genetic 
markers throughout the genome, or analysis of the entire genome. Analysis may be 
conducted if it is hypothesized that this may help further understand the clinical data.
The samples may be analyzed as part of a multistudy assessment of genetic factors involved 
in the response to understand study disease or related conditions.
4.2.1.7
Future Biomedical Research
The Sponsor will conduct FBR on specimens for which consent was provided during this 
study. This research may include genetic analyses (DNA), gene expression profiling (RNA), 
proteomics, metabolomics (serum, plasma), and/or the measurement of other analytes, 
depending on which specimens are consented for FBR.
Such research is for biomarker testing to address emergent questions not described elsewhere 
in the protocol and will only be conducted on specimens from appropriately consented 
participants. The objective of collecting/retaining specimens for FBR is to explore and 
identify biomarkers that inform the scientific understanding of diseases and/or their 
therapeutic treatments. The overarching goal is to use such information to develop safer, 
more effective drugs/vaccines, and/or to ensure that participants receive the correct dose of 
the correct drug/vaccine at the correct time. The details of FBR research are presented in 
Appendix 6.
4.2.2
Rationale for the Use of Placebo
This study will be placebo-controlled to avoid bias in the collection and evaluation of 
efficacy and safety data during the Double-Blind portion of the study, and to assess whether 
any observed effects are treatment-related or an effect of study participation. Participants 
may discontinue the study intervention at any time. Given that there are limited approved 
treatments for vitiligo, and no clear standard of care for treatment, the use of a placebo is 
justified.
4.3
Justification for Dose
MK-6194 will be administered as a 3-mg dose by subcutaneous injection Q2W or Q4W 
based on the available PK, PD, and safety results from Phase 1 SAD and MAD studies in 
healthy participants, participants with ulcerative colitis, and participants with atopic 
dermatitis. MK-6194 PK and PD has been generally similar between UC patients and healthy 
adults.
Published clinical studies have examined the impact of low-dose IL-2 on Treg expansion in a 
range of autoimmune diseases. These studies have shown that the greatest likelihood of 
clinical efficacy is associated with peak Treg expansion of ≥2-fold above baseline across 
differing autoimmune diseases [Rosenzwajg, M., et al 2019] [Allegretti, J., et al 2021] 
[Fanton, C., et al 2020]. A 3-mg dose will result in the majority of participants achieving a 
peak Treg expansion of 2-fold change from baseline while minimizing expansion of CD4+ T 
conventional cells, CD8+ cells, and NK cells. The correlation of Treg expansion and efficacy 
with MK-6194 in autoimmune diseases has not yet been studied.
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Doses up to 5 mg Q2W of MK-6194 have been generally well tolerated and resulted in 
preferential Treg expansion over effector cell populations in participants with UC when 
administered for 12 weeks. Low-dose IL-2 clinical studies have used dosing regimens that 
resulted in sustained or intermittent Treg expansion. Both Q2W and Q4W regimens of MK-
6194 will be studied in this trial to evaluate the impact of sustained or intermittent Treg 
expansion, respectively, on clinical efficacy. A 3-mg dose is anticipated to be generally well
tolerated when administered Q2W or Q4W.
Thus, dosing regimens of 3 mg Q2W and 3 mg Q4W will be studied to evaluate whether 
either of these MK-6194 dosing regimens have a therapeutic impact among participants with 
vitiligo.
4.4
Beginning and End-of-Study Definition
The overall study begins when the first participant (or their legally acceptable representative) 
provides documented informed consent. The overall study ends when the last participant 
completes the last study-related contact, withdraws consent, or is lost to follow-up (Section 
7.3). For purposes of analysis and reporting, the overall study ends when the Sponsor 
receives the last laboratory test result or at the time of final contact with the last participant, 
whichever comes last.
If the study includes countries in the European Economic Area (EEA), the local start of the 
study in the EEA is defined as First Site Ready (FSR) in any Member State.
See Appendix 7 for country-specific requirements.
4.4.1
Clinical Criteria for Early Study Termination
The clinical study may be terminated early if the extent (incidence and/or severity) of 
emerging effects is such that the risk/benefit ratio to the study population as a whole is 
unacceptable. In addition, further recruitment in the study or at (a) particular study site(s) 
may be stopped as described in Appendix 1.10.
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5
STUDY POPULATION
As stated in the Code of Conduct for Clinical Trials (Appendix 1.1), this study includes 
participants of varying age (as applicable), race, ethnicity, and sex (as applicable). The 
collection and use of these demographic data will follow all local laws and participant 
confidentiality guidelines while supporting the study of the disease, its related factors, and 
the IMP under investigation.
Prospective approval of protocol deviations to recruitment and enrollment criteria, also 
known as protocol waivers or exemptions, is not permitted.
5.1
Inclusion Criteria
An individual is eligible for inclusion in the study if the individual meets all of the following 
criteria:
Type of Participant and Disease Characteristics
1. Has a clinical diagnosis of non-segmental vitiligo
Note: Vitiligo diagnosis must be made by a trained physician who is a board-certified 
dermatologist (or local equivalent)
2. Has non-segmental vitiligo with disease duration of at least 6 months
Note: Disease duration is defined as the length of time since onset of symptoms
3.
Has depigmentation contributing to F-VASI ≥ 0.3 at screening and baseline
4. Has depigmented facial BSA ≥0.3% at screening and baseline
5. Has T-VASI ≥4 at screening and baseline
6. Has total body vitiligo area ≥4% at screening and baseline excluding hands and feet 
involvement
7. Is candidate for systemic therapy based on investigator judgment at screening and 
baseline
Demographics
8. Is an individual of any sex/gender, from 18 years to 75 years of age inclusive, at the time 
of providing the informed consent
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Female Participants
9. A participant assigned female sex at birth is eligible to participate if not pregnant or 
breastfeeding, and at least one of the following conditions applies:
•
Is not a POCBP
OR
•
Is a POCBP and:
Uses a contraceptive method that is highly effective (with a failure rate of <1% per year), or 
is abstinent from penile-vaginal intercourse as their preferred and usual lifestyle (abstinent on 
a long-term and persistent basis), as described in Appendix 5 during the intervention period 
and for at least 28 days after the last dose of study intervention. The investigator should 
evaluate the potential for contraceptive method failure (ie, noncompliance, recently initiated) 
in relationship to the first dose of study intervention. Contraceptive use by POCBPs should 
be consistent with local regulations regarding the methods of contraception for those 
participating in clinical studies. If the contraception requirements in the local label for any of 
the study interventions are more stringent than the requirements above, the local label 
requirements are to be followed.
Has a negative highly sensitive pregnancy test (urine or serum) as required by local 
regulations within 24 hours (for a urine test) or 72 hours (for a serum test) before the first 
dose of study intervention. If a urine test cannot be confirmed as negative (eg, an ambiguous 
result), a serum pregnancy test is required. In such cases, the participant must be excluded 
from participation if the serum pregnancy result is positive. Additional requirements for 
pregnancy testing during and after study intervention are in Section 8.3.5.
Abstains from breastfeeding during the study intervention period and for at least 28 days 
after study intervention MK-6194 is last administered.
Medical history, menstrual history, and recent sexual activity has been reviewed by the 
investigator to decrease the risk for inclusion of a POCBP with an early undetected 
pregnancy.
Informed Consent
10. The participant (or legally acceptable representative) has provided documented informed 
consent for the study. The participant may also provide consent for FBR. However, the 
participant may participate in the study without participating in FBR. See Appendix 7 for 
country-specific requirements.
Additional Categories
11. Is willing and considered able by the investigator to comply with study procedures, 
including adherence with study intervention, visit schedule, and completion of PROs. 
Participant must be able to read, understand, and complete the PROs.
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5.2
Exclusion Criteria
An individual must be excluded from the study if the individual meets any of the following 
criteria:
(See Appendix 7 for country-specific requirements).
Medical Conditions
1. Has segmental vitiligo
2. Has ≥50% leukotrichia on face or body
3. Has any other dermatological diseases that would interfere with vitiligo assessments
4. Has history of or current inflammatory condition other than vitiligo that, in the opinion of 
the investigator, could interfere with the evaluation of vitiligo
5. Has a known systemic hypersensitivity to IL-2, or modified IL-2 including MK-6194, or 
its inactive ingredients
Note: Refer to the IB for details regarding excipients for MK-6194.
6. Has a known history of hypereosinophilic syndrome or an eosinophil-related condition 
(eg, eosinophilic pulmonary disease including eosinophilic asthma, eosinophilic 
esophagitis, eosinophilic nephritis, eosinophilic granulomatosis with polyangiitis 
[formerly known as Churg-Strauss syndrome], etc)
7. Has an active or clinically significant infection requiring hospitalization or treatment with 
IV anti-infectives within 4 weeks prior to Randomization, or oral/intramuscular anti-
infective therapy within 2 weeks prior to Randomization
8. Has symptomatic heart failure (New York Heart Association class III or IV) or 
myocardial infarction or unstable angina pectoris within 6 months prior to Screening
9. Has a severe chronic pulmonary disease requiring oxygen therapy
10. Has a transplanted organ, which requires continued immunosuppression
11. Has a history of any malignancy, except for successfully treated non-melanoma skin 
cancer or localized carcinoma in situ of the cervix
12. Is known to be infected with HBV, HCV, or HIV.
•
Participants with positive HBsAg are excluded from the study. Participants with 
negative HBsAg and positive HBcAb must have further testing for HBV-DNA. 
Participants with HBV-DNA ≥LLOQ are not eligible for the study. 
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Note: Participants with HBV-DNA <LLOQ are eligible and the participant should have 
HBV-DNA testing performed approximately every 12 weeks (in correlation with a 
scheduled visit).
•
Participants with positive HCV antibodies at Screening must have further testing for 
HCV-RNA. Participants with HCV-RNA detectable are not eligible for the study. 
Participants with positive HCV antibodies, but HCV-RNA not detectable and 
successfully treated HCV with no recurrence for ≥1 year are eligible.
•
Participants with a history of HIV infection or have a positive antibody test are not 
eligible for the study.
See Appendix 7 for country-specific requirements.
13. Has evidence of active TB, latent TB, or inadequately treated TB (for participants with 
history of TB) as evidenced by one of the following:
•
Positive QuantiFERON-TB Gold test or equivalent test
o
See Section 8.3.6 for TB testing guidance.
•
Positive findings of active TB on CXR (or CT scan if locally required)
o
Note: CXR is not required if the participant had a previous normal CXR per local 
standard of care or chest CT within 90 days prior to Screening, provided all 
source documentation is available and nothing has changed in the participant’s 
medical history to warrant a repeat test.
o
Note: For participants with history of active or latent TB, documentation of 
treatment must be provided to the investigative site. Participants who are fully 
treated per local standard of care are eligible for the study. These participants do 
not require QuantiFERON testing. CXR is still required at Screening; normal 
CXR or CT within 90 days prior to Screening is acceptable.
14. Has confirmed or suspected COVID-19 infection
Note: Participants with recent confirmed or suspected COVID-19 infection may 
participate under the following conditions:
•
Participants with COVID-19 infection confirmed by a PCR or an antigen test:
o
For asymptomatic participants, Randomization must be at least 10 days after the 
positive COVID-19 test.
o
For symptomatic participants, Randomization must be at least 10 days after onset 
of symptoms and at least 3 days after resolution of fever without the use of 
fever-reducing medications, and the participant must have clinically meaningful 
improvement in symptoms.
•
Participants with suspected COVID-19 infection
o
For participants with signs/symptoms suggestive of COVID-19 infection, a 
molecular (ie, PCR) test must be performed to rule out COVID-19 infection prior 
to Randomization;
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OR
o
Randomization must be at least 10 days after onset of symptoms and at least 3 
days after resolution of fever without the use of fever-reducing medications, and
the participant must have clinically meaningful improvement in symptoms.
15. Has history of drug or alcohol abuse within 6 months prior to Screening (can be 
participant reported)
16. Has had major surgery within 3 months prior to Screening OR has a major surgery 
planned during the study
17. Has a concurrent clinically significant disease or clinically relevant laboratory 
abnormalities, or a history of any illness or medical condition that, in the opinion of the 
investigator, might confound the results of the study or poses an additional risk to the 
participant by their participation in the study
Prior/Concomitant Therapy
18. Has had an inadequate response (as evaluated by a dermatologist or local physician 
specialist equivalent) to previous treatment with a JAKi after an appropriate treatment 
duration (eg, ≥12 weeks)
Note: Up to approximately 50% of participants with previous JAKi use study wide are 
eligible if the following criteria are met:

Response to previous treatment with a JAKi after an appropriate treatment duration
(ie, ≥12 weeks)

History of previous JAKi use for <12 weeks regardless of response status
For these participants, the last dose of the JAKi should be ≥4 weeks prior to 
Randomization.
19. Has received prohibited medications within the specified timeframes prior to 
Randomization (Table 1). These medications are also prohibited during the study:
Table 1
Prohibited Medications
Medication Category
Prohibited Period Prior to 
Randomization 
and Any Time During the 
Studya
Biologics and Targeted Immunosuppressive Therapies
Recombinant IL-2
IL-2 muteins/analogs
Immune checkpoint inhibitors
(ie, PD-1 inhibitors, PD-L1 inhibitors, CTLA-4 inhibitors, etc). 
See Appendix 8
Permanent skin bleaching agents
Any time
T-cell depleting therapies (eg, alemtuzumab, antithymocyte globulin)
12 months
B-cell depleting therapies (eg, rituximab, ocrelizumab)
6 months
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Medication Category
Prohibited Period Prior to 
Randomization 
and Any Time During the 
Studya
Biologics with immunosuppressive potential. See Appendix 8 for 
examples of biologics
Note: Non-immunosuppressive biologics may be used after discussion 
with the study Clinical Director
3 months or 5 half-lives 
(whichever is longer)
JAK inhibitors (JAK1, JAK2, JAK3) (including selective inhibition)
TYK2 inhibitors
PDE4 inhibitors
S1P modulators
See Appendix 8 for examples of these medications
4 weeks
Medications Used to Treat Vitiligo
Any drug inducing photosensitivity such as including, but not limited to 
certain antibiotics (eg, tetracyclines), certain NSAIDs
2 weeks
Antioxidants (eg, polypodium leucotomas, superoxide dismutase, alpha-
lipoic acid, Ginko Biloba)
No newly initiated 3 month 
prior to Randomization, and 
the dose should remain stable 
during the study duration
Other topical treatments or any procedures (eg, needling) that could 
affect vitiligo
4 weeks (or 5-drug half-lives)
Systemic or topical non-biologic 
immunomodulators/immunosuppressants (eg, corticosteroids, calcineurin 
inhibitors, tacrolimus/pimecrolimus)
4 weeks for systemic, and 2 
weeks for topical
Any kind of phototherapy (eg, UV/UVB phototherapy, PUVA therapy, 
tanning beds, laser therapy)
4 weeks 
Any other prescription or over-the-counter medication, traditional 
Chinese medicine, herbal supplement, or other therapy used to treat 
vitiligo
4 weeks
Other Therapies
Any investigational drug
4 weeks or 5 half-lives of the 
investigational drug 
(whichever is longer)
Live vaccines
Note: JYNNEOS for prevention of smallpox and mpox, (also known as 
monkeypox disease) is allowed. JYNNEOS is a live, non-replicating 
vaccine.
See Appendix 8 for examples of live and non-live vaccines.
4 weeks (or longer if required 
locally)
CTLA-4=cytotoxic T-lymphocyte-associated protein 4; JAK=Janus kinase; IL-2=interleukin 2; NSAIDs=
nonsteroidal anti-inflammatory drugs; PD-1= programmed cell death protein 1; PDE4= phosphodiesterase-4 enzyme; 
PD-L 1= programmed cell death ligand 1; PUVA=psoralen and ultraviolet rays A; S1P= sphingosine 1 phosphate; 
TYK2= tyrosine kinase 2; UV/UVB=ultraviolet/ultraviolet rays B.
a Medication use is prohibited until the last dose of study intervention is administered (study completion or early 
discontinuation). 
See Appendix 7 for country-specific requirements.
Prior/Concurrent Clinical Study Experience
20. Has participated in another investigational clinical study within 4 weeks (see Table 1 for 
prohibited period) prior to Randomization
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Diagnostic Assessments
21. Has Screening laboratory test results within the following parameters:

Hemoglobin <8.5 g/dL

WBC <3.5 × 103/µL

Absolute neutrophil count <1.5 × 103/μL

Absolute lymphocyte count <0.5 × 103/μL

Absolute eosinophil count >1000 cells/μL

Absolute platelet count <100 × 103/μL

>2.0 X ULN of any of the following: ALT, AST, ALP, or >ULN total bilirubin 
(1.5 X ULN total bilirubin if known Gilbert’s syndrome)

eGFR ≤30 mL/min/1.73 m2, based on the MDRD equation
Note: For any of the above listed laboratory assessments, 1 repeat measurement will be 
allowed at the investigator’s discretion before being considered a screen failure.
Other Exclusions
22. Has donated or lost ≥1 unit of blood (approximately 500 mL) within 4 weeks prior to the 
Screening Visit
23. Has received cosmetic or other procedures that could interfere with evaluation of vitiligo 
during the study
24. Is or has an immediate family member (eg, spouse, parent/legal guardian, sibling, or 
child) who is investigational site or Sponsor staff directly involved with this study.
5.3
Lifestyle Considerations
Blood Donation
Study participants should be instructed not to donate blood or blood products during the 
study.
Sun or Light Exposure
Study participants should be instructed to avoid prolonged exposure to the sun (ie, without 
sufficient SPF protection or in sun conditions where skin could be impacted). The use of 
tanning booths, sun lamps, or other ultraviolet light sources are prohibited during the study.
Makeup/Tattooing/False Eyelashes/Self-Tanning

Permanent and semipermanent makeup is not permitted. Cosmetic makeup is permitted;
however, must be removed for clinical assessments at all study visits.

Tattooing, including procedures such as microblading and micropigmentation, are not 
permitted during the study. Existing tattoos are allowed as long as the assessment of 
vitiligo is not impaired per investigator clinical judgment.
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
False eyelashes are permitted; however, should be removed for clinical assessments at all 
study visits.

Self-tanning and dyes are not permitted during the study.

Laser treatment: intense pulsed light therapy and any laser treatment, including for hair 
removal and skin pigmentation, is not permitted during the study.

Needling is not permitted during the study.

Existing beards are allowed as long as the assessment of vitiligo is not impaired per 
investigator clinical judgment.
5.4
Screen Failures
Screen failures are defined as participants who consent to participate in the clinical study, but 
are not subsequently randomized in the study. A minimal set of screen-failure information is
required to ensure transparent reporting of screen-failure participants to meet the CONSORT 
publishing requirements and to respond to queries from regulatory authorities. Minimal 
information includes demography, screen-failure details, eligibility criteria, and any AEs or 
SAEs meeting reporting requirements as outlined in the data entry guidelines.
Rescreening is allowed once per participant (Section 8.1.6 and Section 8.10.1).
5.5
Participant Replacement Strategy
A participant who discontinues from study intervention or withdraws from the study will not
be replaced.
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6
STUDY INTERVENTION
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.
Clinical supplies study intervention(s) provided by the Sponsor will be packaged to support
enrollment as required. Clinical supplies will be affixed with a clinical label in accordance
with regulatory requirements.
6.1
Study Intervention(s) Administered
The study intervention(s) to be used in this study are outlined in Table 2.
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Table 2
Study Interventions
Arm 
Name
Arm Type
Intervention 
Name
Intervention 
Type
Dose 
Formulation
Unit Dose 
Strength(s)
Dosage 
Level(s)
Route of 
Administration
Treatment 
Period
Use
IMP 
or 
NIMP/
AxMP
Sourcing
MK-
6194 
Q2W
Experimental MK-6194
Biological/Vaccine Injection, 
Solution
3 mg
3 mg
SC
Double-
Blind 
Treatment 
and Blinded 
Extension 
Periods
Test 
Product
IMP
Provided 
centrally 
by 
Sponsor
MK-
6194 
Q4W
Experimental MK-6194
Biological/Vaccine Injection, 
Solution
3 mg
3 mg
SC
Double-
Blind 
Treatment 
and Blinded 
Extension 
Periods
Test 
Product
IMP
Provided 
centrally 
by 
Sponsor
MK-
6194 
Q4W
Experimental Placebo
Biological/Vaccine Injection, 
Solution
0 mg
0 mg
SC
Double-
Blind 
Treatment 
and Blinded 
Extension 
Periods
Placebo IMP
Provided 
centrally 
by 
Sponsor
Placebo
Q2W
Placebo 
Comparator
Placebo
Biological/Vaccine Injection, 
Solution
0 mg
0 mg
SC
Double-
Blind 
Treatment 
Period
Placebo IMP
Provided 
centrally 
by 
Sponsor
EEA= European Economic Area; IMP= investigational medicinal product; NIMP/AxMP= noninvestigational/auxiliary medicinal product; Q2W= every 2 weeks; Q4W= every 4 
weeks; SC= subcutaneous.
The classification of IMP and NIMP/AxMP in this table is based on guidance issued by the European Commission and applies to countries in the EEA. Country differences with 
respect to the definition/classification of IMP and NIMP/AxMP may exist. In these circumstances, local legislation is followed.
Note: To maintain the blind for MK-6194 Q4W, alternating placebo will be administered between the MK-6194 doses. Participants randomized to the placebo arm Q2W during 
the Double-Blind Treatment Period will be rerandomized to MK-6194 Q2W or MK-6194 Q4W during the Blinded Extension Period.
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All supplies indicated in Table 2 will be provided per the “Sourcing” column depending on 
local country operational requirements. If local sourcing, every attempt should be made to 
source these supplies from a single lot/batch number where possible (eg, not applicable in the 
case where multiple lots or batches may be required due to the length of the study, etc).
Refer to Section 8.1.9 for details regarding administration of the study intervention.
6.1.1
Drug-Device Combination Products/Combination Medicinal Product
The investigational drug-device combination product/combination medicinal product
provided for use in this study is MK-6194. Refer to Section 8.4.8 and Appendix 4 for 
reporting events.
6.2
Preparation/Handling/Storage/Accountability
6.2.1
Dose Preparation
There are no specific calculations or evaluations required to be performed to administer the 
proper dose to each participant. The rationale for selection of doses to be used in this study is 
in Section 4.3.
6.2.2
Handling, Storage, and Accountability
The investigator or designee must confirm appropriate temperature conditions have been 
maintained during transit for all study intervention received, and any discrepancies are 
reported and resolved before use of the study intervention.
Only participants enrolled in the study may receive study intervention, and only authorized 
site staff may supply or administer study intervention. All study interventions 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.
The investigator, institution, or the head of the medical institution (where applicable) is 
responsible for study intervention accountability, reconciliation, and record maintenance (ie, 
receipt, reconciliation, and final disposition records).
For all study sites, the local country Sponsor personnel or designee will provide appropriate 
documentation that must be completed for drug accountability and return, or local discard 
and destruction if appropriate. Where local discard and destruction is appropriate, the 
investigator is responsible for ensuring that a local discard/destruction procedure is 
documented.
The study site is responsible for recording the lot number, manufacturer, and expiry date for 
any locally purchased product (if applicable) as per local guidelines unless otherwise 
instructed by the Sponsor.
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The investigator shall take responsibility for and shall take all steps to maintain appropriate 
records and ensure appropriate supply, storage, handling, distribution, and usage of study 
interventions in accordance with the protocol and any applicable laws and regulations.
6.3
Measures to Minimize Bias: Randomization and Blinding
6.3.1
Intervention Assignment
Intervention randomization will occur centrally using an IRT system. There are 3 study 
intervention arms. Participants will be assigned randomly in a 1:1:1 ratio to MK-6194 3 mg 
Q2W, MK-6194 3 mg Q4W, or placebo during the Double-Blind Treatment Period.
During the Blinded Extension Period, participants who were assigned to the placebo arm 
during the Double-Blind Treatment Period will be rerandomized 1:1 to MK-6194 3 mg Q2W 
or MK-6194 3 mg Q4W and will be given new randomization numbers. Participants who 
were assigned to either of the MK-6194 arms during the Double-Blind Treatment Period will 
continue to receive 3 mg MK-6194 with the same dosing schedule; however, will be assigned 
new randomization numbers in order to maintain the study blind during the Blinded 
Extension Period.
In order to maintain the blind, all participants will self-administer study intervention Q2W. 
Participants in the 3 mg MK-6194 Q4W group will alternate between placebo and MK-6194.
If futility criteria are met at the IA in both treatment arms, the study will stop early. If futility 
criteria are met for one treatment arm, participants who complete the Double-Blind 
Treatment Period of the study, but have not started the Blinded Extension Period, will be 
switched to the nonfutile arm for the Blinded Extension Period.
If a dose arm is found to be subefficacious during the Week 24 primary endpoint analysis, 
participants in the Blinded Extension who are already part of the subefficacious dose arm 
may continue on that dose; however, there will be no new enrollment to the subefficacious 
dose arm (Section 9.6). Participants who are still receiving the subefficacious dose in the 
Double-Blind Treatment Period will finish the Double-Blind Treatment Period as 
randomized but will receive the efficacious dose in the Blinded Extension Period.
6.3.2
Stratification
Intervention randomization will be stratified according to the following factors:
1. Stable vs active vitiligo
Treatment response in active versus stable vitiligo might be different.

Active vitiligo is defined as new/extending lesion(s) in the 6 months prior to 
Screening Visit (confirmed by photographs or medical record/history) and/or; 
confetti-like lesion(s); trichrome lesion(s); Koebner phenomenon/phenomena 
(excluding Type 1 [history based on isomorphic reaction]), inflammatory vitiligo.

Stable vitiligo is defined as an absence of signs of active disease (no signs of new 
or extending lesions).
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2. Previous JAKi exposure (yes or no)
•
It is unknown whether exposure to JAKi may affect response to an IL-2 mutein or if an 
inadequate response to JAKi may predict an inadequate response to MK-6194.
6.3.3
Blinding
A double-blinding technique with in-house blinding will be used. MK-6194 and placebo will 
be packaged identically so that blind is maintained.
Clinical site personnel, participants, and most Sponsor personnel will remain blinded for the 
duration of the study (ie, through Week 54). Only selected Sponsor personnel involved in 
performing and reviewing the results of the Week 24 analyses will be unblinded at the time 
of the Week 24 database lock.
See Section 8.1.11 for the description of unblinding if a medical emergency occurs during the 
study.
6.4
Study Intervention Compliance
Interruptions from the protocol-specified treatment plan for ≥ 2 consecutive injections
require consultation between the investigator and the Sponsor and written documentation of 
the collaborative decision on participant management.
When participants self-administer study intervention at the site (witnessed doses per SoA), 
compliance with study intervention will be assessed by site personnel observation. 
Alternatively, participants may receive study intervention directly from the investigator or 
designee. The date and time of each dose administered in the clinic will be recorded in the 
source documents, the CRF, and the Participant Reminder Log.
When participants self-administer study intervention away from the clinic, compliance with 
study intervention will be assessed at the following site visit. Participants will record the date 
and time of the administered dose on the Participant Reminder Log. Compliance will be 
assessed by direct questioning during review of the Participant Reminder Log and inspection 
of the returned study intervention syringe(s) (used and unused, when applicable) and 
documented in the source documents and CRF. Deviation(s) from the prescribed dosage 
regimen should be recorded in the CRF.
If a discrepancy is noted when comparing entries in the Participant Reminder Log with the 
amounts of returned study intervention, the investigator or qualified designee must discuss 
the discrepancy with the participant and the explanation must be documented. Only the 
participant is allowed to make any changes to the log entries. The investigator or qualified 
designee will be responsible for transferring the appropriate information from the log into the 
appropriate CRF.
A record of the number of prefilled syringes dispensed to and administered by each 
participant must be maintained and reconciled with study intervention and compliance 
records. Intervention administration dates will also be recorded in the CRF.
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6.5
Concomitant Therapy
Prohibited Concomitant Medications
Medications or vaccinations specifically prohibited in the exclusion criteria are also 
prohibited during the study. Please refer to Table 1 (in Section 5.2) for medications which are 
prohibited during the study until the last dose of study intervention. Live vaccines, except for 
JYNNEOS, are prohibited during the study until 6 weeks after the last dose of study 
intervention. See Appendix 8 for examples of live vaccines and Appendix 7 for country-
specific requirements.
Any prescription or over-the-counter medication, traditional Chinese medicine, herbal 
supplement, or other therapy used to treat vitiligo (or could affect vitiligo) are prohibited 
during the study to avoid confounding of results.
If there is a clinical indication for any medications or vaccinations specifically prohibited, 
discontinuation from study intervention may be required. The investigator should discuss any 
questions regarding this with the Sponsor Clinical Director. The final decision on any
supportive therapy or vaccination rests with the investigator and/or the participant’s primary 
physician. However, the decision to continue the participant on study intervention requires 
the mutual agreement of the investigator, the Sponsor, and the participant.
Any medication or vaccine (including over-the-counter or prescription medicines, vitamins, 
and/or herbal supplements or other specific categories of interest) that the participant is 
receiving at the time of enrollment or receives during the study must be recorded along with:
•
Reason for use
•
Dates of administration including start and end dates
•
Dosage information including dose, route, and frequency
The Sponsor Clinical Director should be contacted if there are any questions regarding 
concomitant or prior therapy.
Note: It is the responsibility of the investigator to ensure participants with concomitant
medical conditions are treated according to local guidelines/standard of care.
6.5.1
Rescue Medications and Supportive Care
No rescue or supportive medications are specified for use in this study.
6.6
Dose Modification
There are no dose modifications in this study.
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6.6.1
Management of Serious Adverse Event of Infection
Interrupt study intervention if a participant develops an SAE of infection. Study intervention 
may be restarted once the infection has been successfully treated, per investigator discretion.
6.6.2
Management of COVID-19 Infection
Interrupt study intervention if a participant has a confirmed diagnosis of COVID-19 
infection. Study intervention may be restarted once the infection or symptom is resolved, per 
investigator discretion.
6.6.3
Management of Eosinophilia
For participants with AEC ≤650 cells/μL at Screening:
•
If AEC is >1000 cells/μL at a scheduled or unscheduled visit after Randomization, 
another CBC with differential must be performed before the next dose. It is 
recommended to perform the CBC with differential close to the next dosing day and at 
least 10 days after the prior dose.
•
If AEC is still >1000 cells/μL, a CBC with differential may be repeated the day before 
the dosing day or on the dosing day, prior to administration of study intervention.
•
If AEC remains >1000 cells/μL, study intervention should be interrupted. Study 
intervention may be restarted once AEC is ≤1000 cells/μL.
For participants with AEC >650 cells/μL at Screening:
•
If AEC at a scheduled or unscheduled visit after Randomization has an increase of
≥500 cells/μL above the Screening value, another CBC with differential must be 
performed before the next dose. It is recommended to perform the CBC with differential 
close to the next dosing day and at least 10 days after the prior dose.
•
If AEC is >1000 cells/μL, a CBC with differential may be repeated the day before the 
dosing day or on the dosing day, prior to administration of study intervention.
•
If AEC remains >1000 cells/μL, study intervention should be interrupted. Study 
intervention may be restarted once AEC is ≤1000 cells/μL.
Hypereosinophilic syndrome and eosinophil-associated organ injury are described in 
Appendix 9.
6.7
Intervention After the End of the Study
There is no study-specified intervention after the end of the study.
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6.8
Clinical Supplies Disclosure
The emergency unblinding call center will use the intervention/randomization schedule for 
the study to unblind participants and to unmask study intervention identity. The emergency 
unblinding call center should only be used in cases of emergency (see Section 8.1.11). If the 
emergency unblinding call center is not available for a given site in this study, the central 
electronic IRT should be used to unblind participants and to unmask study intervention 
identity. The Sponsor will not provide random code/disclosure envelopes or lists with the 
clinical supplies.
6.9
Standard Policies
Not applicable
6.9.1
Study Site Retention Samples
Not applicable
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7
DISCONTINUATION OF STUDY INTERVENTION AND PARTICIPANT 
WITHDRAWAL
7.1
Discontinuation of Study Intervention
Discontinuation of study intervention does not represent withdrawal from the study.
As certain data on clinical events beyond study intervention discontinuation may be 
important to the study, they must be collected through the participant’s last scheduled follow-
up, even if the participant has discontinued study intervention. Therefore, all participants 
who discontinue study intervention before completion of the protocol-specified treatment 
period will still continue to be monitored in the study and participate in the study visits and 
procedures as specified in Section 1.3 and Section 8.10.5 unless the participant has 
withdrawn from the study (Section 7.2).
Participants may discontinue study intervention at any time for any reason or be discontinued 
from the study intervention at the discretion of the investigator should any untoward effect
occur. In addition, a participant may be discontinued from study intervention by the 
investigator or the Sponsor if study intervention is inappropriate, the study plan is violated, or 
for administrative and/or other safety reasons.
A participant must be discontinued from study intervention, but continue to be monitored in 
the study for any of the following reasons:
•
The participant or participant’s legally acceptable representative requests to discontinue 
study intervention.
•
The participant’s treatment assignment has been unblinded by the investigator, MSD 
subsidiary, or through the emergency unblinding call center.
•
The participant has a medical condition or personal circumstance, which, in the opinion 
of the investigator and/or Sponsor, places the participant at unnecessary risk from 
continued administration of study intervention.
•
The participant has a confirmed positive serum pregnancy test.
•
The participant has AEC >1500 cells/µL and has confirmed or suspected 
hypereosinophilic syndrome or eosinophil-associated organ injury; see Appendix 9 for 
details.
•
The participant has a persistent moderate increase in eosinophils for ≥8 weeks, defined as 
AEC ≥1500 cells/µL on at least 3 consecutive tests. The interval between the tests should 
be at least 1 week.
•
The participant has AEC >5000 cells/µL at a single time point.
•
The participant develops active or latent TB.
•
The participant has an SAE of infection (eg, sepsis), which cannot be adequately 
controlled by anti-infective treatment.
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•
The participant has any malignancy, except for surgically removed and cured localized 
non-melanoma skin cancer or carcinoma in situ of the cervix.
•
The participant is diagnosed with HBV, HCV, or HIV.
•
The participant has HBV-DNA ≥LLOQ.
For participants who are discontinued from study intervention, but continue to be monitored 
in the study, selected visits and procedures, as outlined in the SoA and Section 8.10.5, should 
be completed.
Discontinuation from study intervention is “permanent.” Once a participant is discontinued 
from study intervention, they shall not be allowed to restart study intervention.
See Appendix 7 for country-specific requirements. 
7.2
Participant Withdrawal From the Study
A participant must be withdrawn from the study if the participant or participant’s legally 
acceptable representative withdraws consent from the study.
If a participant withdraws from the study, they will no longer receive study intervention or be 
followed at scheduled protocol visits.
Specific details regarding procedures to be performed at the time of withdrawal from the 
study, as well as specific details regarding withdrawal from FBR, are outlined in 
Section 8.1.10. The procedures to be performed should a participant repeatedly fail to return 
for scheduled visits and/or if the study site is unable to contact the participant are outlined in 
Section 7.3.
A participant or participant’s legally acceptable representative who consented for the 
Subpopulation procedures, may withdraw consent for the additional PK/PD/Biomarker 
sample collection. Specific details regarding activities to be performed at the time of 
withdrawal from the Subpopulation procedures are outlined in Section 8.1.10.2. Withdrawal 
from the Subpopulation does not represent withdrawal from the main study.
See Appendix 7 for country-specific requirements. 
7.3
Lost to Follow-up
If a participant fails to return to the clinic for a required study visit and/or if the site is unable 
to contact the participant, the following procedures are to be performed:
•
The site must attempt to contact the participant and reschedule the missed visit. If the 
participant is contacted, the participant should be counseled on the importance of 
maintaining the protocol-specified visit schedule.
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•
The investigator or designee must make every effort to regain contact with the participant 
at each missed visit (eg, telephone calls and/or a certified letter to the participant’s last 
known mailing address or locally equivalent methods). These contact attempts should be 
documented in the participant’s medical record.
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8
STUDY ASSESSMENTS AND PROCEDURES
•
Study procedures and their timing are summarized in the SoA.
•
Adherence to the study design requirements, including those specified in the SoA, is 
essential and required for study conduct.
•
The investigator is responsible for ensuring that procedures are conducted by 
appropriately qualified (by education, training, and experience) staff. Delegation of 
study-site personnel responsibilities will be documented in the Investigator Trial File 
Binder (or equivalent).
•
All study-related medical (or dental) decisions must be made by an investigator who is a 
qualified physician (or dentist when appropriate).
•
All screening evaluations must be completed and reviewed to confirm that potential 
participants meet all eligibility criteria. The investigator will maintain a screening log to 
record details of all participants screened and to confirm eligibility or record reasons for 
screening failure, as applicable.
•
Procedures conducted as part of the participant’s routine clinical management (eg, blood 
count) and obtained before providing documented informed consent may be used for 
screening or baseline purposes provided the procedures meet the protocol-specified 
criteria and were performed within the time frame defined in the SoA.
•
Additional evaluations/testing may be deemed necessary by the investigator and or the 
Sponsor for reasons related to participant safety. In some cases, such evaluation/testing 
may be potentially sensitive in nature (eg, HIV, hepatitis C), and thus local regulations 
may require that additional informed consent be obtained from the participant. In these 
cases, such evaluations/testing will be performed in accordance with those regulations.
•
The maximum amount of blood collected from each participant over the duration of the 
study will not exceed the volume mentioned in the Laboratory Manual.
•
Repeat or unscheduled samples may be taken for safety reasons or for technical issues 
with the samples.
8.1
Administrative and General Procedures
8.1.1
Informed Consent
Informed consent will adhere to IRB/IEC requirements, applicable laws and regulations, and 
Sponsor requirements. The ICF, any subsequent revised ICF, and any written information 
provided to the participant must receive the IRB/IEC’s approval/favorable opinion in 
advance of use.
Informed consent given by the participant (or their legally acceptable representative) must be 
documented on a consent form. The form must include the study protocol number, study 
protocol title, dated signature, and agreement of the participant (or their legally acceptable 
representative) and of the person conducting the consent discussion.
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A copy of the signed and dated ICF should be given to the participant (or their legally 
acceptable representative) before participation in the study.
The investigator or medically qualified designee (consistent with local requirements) must 
obtain documented informed consent from each potential participant (or their legally 
acceptable representative) prior to participating in this clinical study or FBR. If there are 
changes to the participant’s status during the study (eg, health or age of majority 
requirements), the investigator or medically qualified designee must ensure the appropriate 
documented informed consent is in place.
See Appendix 7 for country-specific requirements. 
8.1.1.1
General Informed Consent
Specifics about the study and the study population are to be included in the ICF.
The participant (or their legally acceptable representative) should be informed in a timely 
manner if new information becomes available that may be relevant to the participant’s 
willingness to continue participation in the study. The communication of this information 
will be provided and documented via a revised consent form or addendum to the original 
consent form that captures the participant’s or the participant’s legally acceptable 
representative’s dated signature.
See Appendix 7 for country-specific requirements. 
8.1.1.2
Consent and Collection of Specimens for Future Biomedical Research
The investigator or medically qualified designee will explain the FBR consent to the 
participant, or the participant’s legally acceptable representative, answer all his/her questions, 
and obtain documented informed consent before performing any procedure related to FBR. A 
copy of the informed consent will be given to the participant before performing any 
procedure related to FBR.
See Appendix 7 for country-specific requirements.
8.1.1.3
Consent for PK/PD/Biomarker Subpopulation
The investigator or medically qualified designee at selected sites will explain the consent for 
additional PK/PD/Biomarker sample collection to participants, or the participant’s legally 
acceptable representative, answer all of his/her questions, and obtain documented informed 
consent before performing any procedure related to the PK/PD/Biomarker Subpopulation. A 
copy of the informed consent will be given to the participant before performing any 
procedure related to the PK/PD/Biomarker Subpopulation.
See Appendix 7 for country-specific requirements.
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8.1.2
Inclusion/Exclusion Criteria
All inclusion and exclusion criteria (Sections 5.1 and 5.2) will be reviewed at the Screening 
and Randomization Visits as outlined in the SoA (Section 1.3.1) by the investigator, or 
subinvestigator delegate, who is a qualified physician, to ensure that the participant qualifies 
for the study.
8.1.3
Participant Identification Card
All participants will be given a participant identification card identifying them as participants 
in a research study. The card will contain study-site contact information (including direct 
telephone numbers) to be used in the event of an emergency. The investigator or qualified 
designee will provide the participant with a participant identification card immediately after 
the participant provides documented informed consent. At the time of intervention
randomization, site personnel will add the treatment/randomization number to the participant 
identification card.
The participant ID card also contains contact information for the emergency unblinding call 
center so that a health care provider can obtain information about study intervention in 
emergency situations where the investigator is not available.
For the Blinded Extension Period, each participant who completes the Double-Blind 
Treatment Period per protocol requirements will receive a new participant identification card 
at Visit 10; the rerandomization number will be added to the new participant identification 
card. The participant identification card from the Double-Blind Treatment Period should be 
collected at this time. 
8.1.4
Medical History
A medical history will be obtained by the investigator or qualified designee at the Screening 
Visit. Participants will be asked to provide any background or concomitant conditions, drug 
allergies, surgical procedures, or other medical conditions. Additionally, a complete vitiligo 
medical history will be collected.
Clinically significant findings in physical examination, laboratory tests, ECGs, and other 
physical evaluations during Screening are to be noted in the medical history. Clinically 
significant changes from the Screening evaluation during the study should be captured as 
AEs.
8.1.5
Prior and Concomitant Medications Review
8.1.5.1
Prior Medications
The investigator or qualified designee will review prior medication use, including any 
protocol-specified washout requirements (Table 1, Section 6.5, and Appendix 8), and record 
prior medications taken by the participant. All treatment with JAKi and vitiligo treatments or 
other prohibited medications, regardless of timing, must be recorded.
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All other medications taken within 30 days prior to Screening should be recorded.
8.1.5.2
Concomitant Medications
The investigator or qualified designee will record medications, if any, taken by the 
participant during the study. Prohibited concomitant medications, therapies, and products, as
outlined in Section 5.2 (Table 1), Section 6.5, and Appendix 8, should not be administered 
from the indicated period before Randomization to last dose of study intervention 
administration.
8.1.6
Assignment of Screening Number
All consented participants will be given a unique screening number that will be used to 
identify the participant for all procedures that occur before Randomization. Each participant 
will be assigned only 1 screening number. Screening numbers must not be reused for 
different participants.
Any individual who is screened twice will retain the original screening number assigned at 
the initial Screening Visit. Specific details on the screening/rescreening visit requirements are 
in Section 8.10.1. Prestudy screening logs may be collected for review by the Sponsor. If 
applicable, any information that would make the participant identifiable will be removed.
8.1.7
Assignment of Randomization Number
All eligible participants will be randomly allocated and will receive a randomization number. 
The randomization number identifies the participant for all procedures occurring after 
Randomization. Once a randomization number is assigned to a participant, it can never be 
reassigned to another participant.
All participants who complete the Double-Blind Treatment Period per protocol requirements 
will be rerandomized to MK-6194 3 mg Q2W or MK-6194 3 mg Q4W and will be assigned a 
new randomization number for the Blinded Extension Period.
8.1.8
IRT Visit Registration, IRT Randomization, and Study Intervention 
Dispensing
The investigator (or designee) will register the participant in IRT at the visits specified in the 
SoA. Participants who satisfy all entry criteria will be assigned a randomization number via 
IRT at Visit 2 (Day 1). A second randomization number will be assigned via IRT at Visit 10 
for all participants who complete the Double-Blind Treatment Period per protocol 
requirements. 
IRT will allow randomization of up to approximately 50% of participants study wide with 
previous JAKi use. IRT will manage the participant’s stratification as outlined in 
Section 6.3.2 and the Blinded Extension rerandomization of the placebo group as outlined in 
Section 6.3.1.
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Participants who do not meet eligibility criteria will be entered into IRT as screen failures. 
IRT will also be used to identify the study intervention supplies that will be dispensed to 
participants at the visits specified in the SoA. Details about the IRT system will be provided 
in a separate manual.
IRT will be contacted for participant closeout purposes at the Discontinuation Visit or the 
Week 52 Visit.
8.1.9
Study Intervention Administration
Self-administration of study intervention is recommended; however, administration of study 
intervention by site personnel or a caregiver/family member is permitted. Self-administration 
should be in one of the approved injection sites as outlined in the “MK-6194 Instructions for 
Use” provided to the participant. All participants will be instructed NOT to inject in an 
inflamed area. Participants will be trained on the proper technique of self-administration and 
be advised to review the “MK-6194 Instructions for Use” before their first injection. 
Retraining should occur as necessary at subsequent visits. See Appendix 7 for country-
specific requirements.
Details on appropriate handling, storage, and accountability of study intervention are 
provided in Section 6.2.2.
8.1.9.1
Timing of Dose Administration
When a study site visit is scheduled, self-administration of study intervention should take 
place at the study site after all required procedures have been performed. A witnessed dose is 
not required unless specified in the SoA (Section 1.3). In order to maintain the blind, all 
participants should administer study intervention doses approximately every 
 days (and at 
a minimum of 
 
Enough study intervention supplies will 
be provided to the participant to allow for self-administration of required doses in between 
clinic visits. Participants will be instructed to review the “MK-6194 Instructions for Use” 
when administering injections of study intervention at home.
Contact the Sponsor if the participant misses ≥2 consecutive injections (Section 6.4).
8.1.9.2
Study Intervention Dispense or Return
Study intervention prefilled syringe(s) will be provided to each participant at the times 
outlined in the SoA. All used (and unused, as applicable) study intervention prefilled 
syringes must be returned at the end of each study visit as outlined in the SoA. Study sites 
will keep track of returned syringes to assess study intervention administration compliance.
8.1.9.3
Train or Retrain Participant on Self-administration of Study Intervention
All participants and/or caregivers/family members will be trained by the appropriate study 
staff on the proper administration of study intervention technique before the participant’s first 
injection. Training or retraining will take place during the study visits marked in the SoA and 
CC
I
CCI
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at other visits on an as-needed basis (see Section 8.1.9). Participants will receive written 
instructions and will be directed to review the “MK-6194 Instructions for Use” prior to 
self-administration of study intervention. See Appendix 7 for country-specific requirements.
Individuals responsible for administering study intervention will be instructed NOT to inject 
into an inflamed area.
8.1.9.4
Witnessed Dose
Study intervention administration should be witnessed and documented by the investigator 
and/or study staff during visits as outlined in the SoA. Self-administration of study 
intervention by the participant, or administration by a caregiver/family member, should occur 
after completion of all study procedures, including collection of all blood samples. The study 
site staff will ensure proper self-administration technique. Participants will document dosing 
in the Participant Reminder Log.
Additionally, on study visit days when the dose is not required to be witnessed by the 
investigator and/or study staff, administration at the study site (whether by participant or 
caregiver/family member/site staff) is preferred, but not required.
See Appendix 7 for country-specific requirements.
8.1.9.5
Dosing Reminder
Participant Reminder Log
A paper ‘Participant Reminder Log’ will be provided to each randomized participant for 
documentation of study intervention administration (each dose administered), any 
complaints/illnesses, and any new medications taken between study visits. Participants will 
be trained on how to use and complete the ‘Participant Reminder Log’ at the visits outlined
in the SoA.
Participants should be instructed to bring their completed ‘Participant Reminder Log’ to each 
study visit. The investigator and/or designee will review the ‘Participant Reminder Log’ with 
the participant at the next visit for accuracy, and any errors/discrepancies should be corrected 
by the participant per GCP (one line cross-out with initials/date of change). The investigator 
and/or designee will then collect the ‘Participant Reminder Log’ from participants at the 
visits described in the SoA. The information recorded in the ‘Participant Reminder Log’ will 
be used to assist the investigator (and/or designee) in assessing study medication compliance, 
identifying potential AEs, and determining whether any concomitant medications were taken; 
applicable study data will be recorded on the appropriate eCRF.
Participant Reminder Telephone Call
Telephone contacts will be made to assess compliance of study intervention administration 
away from the clinic at specific visits outlined in the SoA (Section 1.3). During the telephone 
call, AE and concomitant medication information will also be reviewed. Additional reminder 
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telephone calls are recommended if a participant has not been compliant with administration 
of study intervention or when deemed necessary by the study site.
8.1.10
Discontinuation and Withdrawal
Participants who discontinue study intervention before completion of the treatment period
will have a Discontinuation Visit and should be encouraged to continue to be followed for all 
remaining study visits until the end of the study period in which they discontinued as 
outlined in the SoA and Section 8.10.5.
Participants who withdraw from the study should be encouraged to complete all applicable 
activities scheduled for the Discontinuation Visit at the time of withdrawal. Any AEs that are 
present at the time of withdrawal should be followed in accordance with the safety 
requirements outlined in Section 8.4.
8.1.10.1
Withdrawal From Future Biomedical Research
Participants may withdraw their consent for FBR. Participants may withdraw consent at any 
time by contacting the study investigator. If medical records for the study are still available, 
the investigator will contact the Sponsor using the designated mailbox 
(clinical.specimen.management@MSD.com). Subsequently, the participant’s consent for 
FBR will be withdrawn. A letter will be sent from the Sponsor to the investigator confirming 
the withdrawal. It is the responsibility of the investigator to inform the participant of 
completion of withdrawal. Any analyses in progress at the time of request for withdrawal or 
already performed before the request being received by the Sponsor will continue to be used 
as part of the overall research study data and results. No new analyses would be generated 
after the request is received.
If the medical records for the study are no longer available (eg, if the investigator is no longer 
required by regulatory authorities to retain the study records) or the specimens have been 
completely anonymized, there will no longer be a link between the participant’s personal 
information and their specimens. In this situation, the request for specimen withdrawal 
cannot be processed.
8.1.10.2
Withdrawal From Additional PK/PD/Biomarker Subpopulation
Participants may withdraw consent for the Subpopulation procedures (Section 1.3.3) at any 
time by contacting the study investigator. Any analyses in progress at the time of request for 
withdrawal or already performed before the request being received by the Sponsor will 
continue to be used as part of the overall research study data and results. No new analyses 
would be generated after the request is received. Specific details regarding activities to be 
performed at the time of withdrawal from the Subpopulation procedures are outlined in 
Section 8.10.5.
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8.1.11
Participant Blinding/Unblinding
STUDY INTERVENTION IDENTIFICATION INFORMATION IS TO BE UNMASKED 
ONLY IF NECESSARY FOR THE WELFARE OF THE PARTICIPANT. EVERY 
EFFORT SHOULD BE MADE NOT TO UNBLIND.
For emergency situations where the investigator or medically qualified designee (consistent 
with local requirements) needs to identify the intervention used by a participant and/or the 
dosage administered, he/she will contact the emergency unblinding call center by telephone 
and make a request for emergency unblinding. As requested by the investigator or medically 
qualified designee, the emergency unblinding call center will provide the information to 
him/her promptly and report unblinding to the Sponsor. Before contacting the emergency 
unblinding call center to request unblinding of a participant’s intervention assignment, the 
investigator who is a qualified physician should make reasonable attempts to enter the
intensity of the AEs observed, the relation to study intervention, the reason thereof, etc, in the 
medical record. If it is not possible to record this assessment in the medical record before the 
unblinding, the unblinding should not be delayed.
If unblinding has occurred, the circumstances around the unblinding (eg, date, reason, and 
person performing the unblinding) must be documented promptly, and the Sponsor Clinical 
Director notified as soon as possible.
Once an emergency unblinding has taken place, the investigator, site personnel, and Sponsor 
personnel may be unblinded so that the appropriate follow-up medical care can be provided 
to the participant.
Participants whose treatment assignment has been unblinded by the investigator or medically 
qualified designee and/or nonstudy treating physician must be discontinued from study 
intervention, but should continue to be monitored in the study. 
Additionally, the investigator or medically qualified designee must go into the IRT system 
and perform the unblind in the IRT system to update drug disposition. If the emergency 
unblinding call center is not available for a given site in this study, the IRT system should be 
used for emergency unblinding if this is required for participant safety.
At the end of the study, random code/disclosure envelopes or lists and unblinding logs are to 
be returned to the Sponsor or designee.
8.1.12
Calibration of Equipment
The investigator or qualified designee has the responsibility to ensure that any device or 
instrument used for a clinical evaluation/test during a clinical study that provides information 
about inclusion/exclusion criteria and/or safety or efficacy parameters shall be suitably 
calibrated and/or maintained to ensure that the data obtained are reliable and/or reproducible. 
Documentation of equipment calibration must be retained as source documentation at the 
study site.
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8.1.13
PK/PD/Biomarker Subpopulation
At selected sites, additional PK/PD/Biomarker samples will be collected from 
>15 participants per treatment arm, as outlined in the SoA (Section 1.3.3), in addition to the 
samples listed in the Double-Blind Treatment and Blinded Extension Periods (Sections 1.3.1 
and 1.3.2).
The purpose of the Subpopulation is to provide additional PK and PD measurements, 
allowing a more comprehensive characterization of the PK-PD relationship of MK-6194. The 
additional PD and biomarker sample collection is to enable Treg and other biomarker 
assessments at more timepoints, to allow better understanding of PD and biomarker 
responses to MK-6194 in participants with vitiligo.
8.2
Efficacy Assessments
8.2.1
PROs
All PROs should be completed in the order listed in the SoA before laboratory tests or any 
other efficacy or safety procedures, except for Visit 2 (Randomization) where PROs can be 
completed after confirming eligibility. Participants will be trained by site personnel on the 
use of an electronic tablet for PRO completion and are to complete the questionnaires on 
their own at the study site using the provided electronic tablet.
VitiQoL
The VitiQoL is a 16-item validated, disease-specific instrument that measures the impact of 
vitiligo on patients’ social, emotional and physical functioning [Lilly, E., et al 2013]. Items 
are scored using a 7-point Likert scale (0 – 6), with lower scores indicating better quality of 
life.
Vitiligo Noticeability Scale
The VNS is a single-item measure that asks patients to rate the noticeability of their vitiligo 
compared with before they started treatment on a 5-point scale ranging from 1 (more 
noticeable) to 5 (no longer noticeable). Scores of 4 – 5 are considered indicative of treatment 
success.
Patient Global Impression of Severity
The PGI-S is a 2-item measure asking the participant to rate the severity of their vitiligo on 
their facial area and on their total body area right now, with response options of none, mild, 
moderate, severe, and very severe.
Patient Global Impression of Change/Meaningfulness
The PGIC/M is a 2-part measure asking the participant to rate the change in their vitiligo
since they started taking the study medication, with response options ranging from “much 
better” to “much worse”. Based on the response to the initial question, the participant is 
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asked a follow-up question to evaluate the meaningfulness of the improvement or worsening, 
with response options of “yes” or “no” indicating whether the improvement or worsening 
was important to the participant or not.
8.2.2
ClinROs
All ClinROs should be completed in the order listed in the SoA. The investigator or 
medically qualified designee are to complete the questionnaires using the provided electronic 
tablet. Separate instructions on how to complete the ClinROs will be available if needed.
Investigator qualifications, training, and applicable certification processes are established in a 
separate document. It is strongly encouraged that the same investigator evaluates the same 
participant for the duration of the study to improve continuity and reliability of the 
assessments.
Clinical Global Impression of Severity
The CGI-S is a 2-item measure asking the investigator to rate the severity of participant’s 
vitiligo on their facial area and on the total body area right now, with response options of 
none, mild, moderate, severe, and very severe.
Clinical Global Impression of Change
The CGI-C is a 2-item measure asking the investigator to rate the change in the participant’s 
vitiligo on their facial area and on the total body area since they started taking the study
medication, with response options ranging from “much better” to “much worse”.
Facial Vitiligo Area Scoring Index (F-VASI) and Total Vitiligo Area Scoring Index (T-
VASI) 
The VASI is a validated scoring method that assesses the extent and severity of areas of 
vitiligo depigmentation. There are 2 region-specific VASI scores that will be calculated for 
the study; the F-VASI, which measures vitiligo involvement of the facial area, and the
T-VASI, which measures vitiligo involvement for the total body. Both are scored by 
measuring the total area of depigmentation, as measured by a standard unit, multiplied by the 
percent of depigmentation of the affected areas.
F-VASI is defined as the sum of the area(s) of all vitiligo lesions on the Face X Average
Degree of Depigmentation (%).
The FACE is defined as the area between the hairline, chin, and up to the ears. This area 
includes the eyelids, cheeks, and nose, but DOES NOT INCLUDE the lips, scalp, ears, or 
neck.
Vitiligo lesions on face will be estimated by using a fingertip unit (1 FTU), a finger 
(3 FTUs), or a thumb (3 FTUs) depending on the lesion size. One FTU is equivalent to 
0.03% of the body surface are (BSA) and a finger and thumb are considered 0.1% BSA. The 
degree of depigmentation for each vitiligo involvement site is determined and estimated to 
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the nearest of the following percentages: 0% (no depigmentation), 10%, 25%, 50%, 75%, 
90%, or 100% (complete depigmentation). The F-VASI is derived by multiplying the values 
assessed for the vitiligo involvement by the percentage of affected skin for each site on the 
face and summing the values of all sites together. Possible scores range from 0-3.5.
The T-VASI determines the degree of vitiligo involvement of the whole body. The total body 
is separated into 6 mutually exclusive areas: 1. Head/Neck (Including the Face), 2. Hands, 3. 
Upper extremities (Excluding the hands), 4. Trunk (Including genitalia; Excluding buttocks), 
5. Lower extremities (Including buttocks; Excluding the feet), and 6. Feet. The area of 
depigmentation will be measured by using the palmar method, whereupon one hand unit 
(comprised of the patient’s palm + 5 digits, with fingers tucked together & thumb tucked to 
the side) = 1% Body Surface Area. As for the F-VASI, the degree of depigmentation for each 
vitiligo involvement site is determined and estimated to the nearest of the following 
percentages: 0% (no depigmentation), 10%, 25%, 50%, 75%, 90%, or 100% (complete 
depigmentation). Where there are multiple lesions within a body region, the degree of 
depigmentation within each body region should be estimated using the above percentages
and then averaged to the closest overall percentage. For example, if there are 3 vitiligo 
lesions within a body region, with degrees of depigmentation of 75%, 50% and 100%, the 
estimated average degree of depigmentation for that region would be 75%.
The area of percent depigmentation scores for each body region are summed to derive the 
T-VASI score, which ranges from 0 to 100, with 0 indicating no vitiligo and 100 indicating 
vitiligo on the entire body. Note that, when a lesion crosses over more than one region, the 
scoring for the lesion is not split between regions; the investigator will select one of the 
regions to include that lesion in to calculate the VASI for that region, always including that 
lesion in the same region for all future assessments.
Body Surface Area
The participant’s right or left hand should be selected as the measuring device. For purposes 
of clinical estimation, the total surface of the palm plus 5 digits, with fingers tucked together 
and thumb tucked to the side, will be assumed to be approximately equivalent to 1% BSA. 
Measurement of the total area of involvement by the physician is aided by clinical judgment
(ie, if specks of pigment were moved so that they were next to each other and then estimating 
the total area involved). The site should make every attempt to have the same qualified 
investigator or designee perform all BSA assessments on a given participant throughout the 
study.
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8.2.3
Photography
Photography of the face and/or body areas affected with vitiligo will be obtained at the times 
outlined in the SoA using the provided electronic tablet to support the F-VASI, T-VASI, and 
Photographs will be anonymized to the extent possible in order to protect 
participant’s identity. Additional instructions and a full description of the methodology for 
obtaining photographs are provided in a separate manual. Photographs will not be used for
formal assessments of efficacy; however, may be included in the CSR or other publications.
The F-VASI and T-VASI photographs will be reviewed centrally; however, it is the 
investigator’s VASI score that will be used for efficacy calculations. If the photographs 
obtained at Screening are deemed sufficient by the central reviewer, no additional 
photographs are required at the randomization visit.
8.3
Safety Assessments
Details regarding specific safety procedures/assessments to be performed in this study are 
provided. The total amount of blood/tissue to be drawn/collected over the course of the study 
(from prestudy to poststudy visits), including approximate blood/tissue volumes 
drawn/collected by visit and by sample type per participant, can be found in the Laboratory 
Manual.
Planned time points for all safety assessments are provided in the SoA.
8.3.1
Physical Examinations
A full physical examination will be conducted by an investigator or medically qualified 
designee (consistent with local requirements) per institutional standard at the visits listed in 
the SoA.
The full examination should be based on the following body systems: general appearance, 
head (oral inspection, ears, eyes, nose, and throat), respiratory (auscultation/stethoscopy 
examination of the lungs), heart (auscultation/stethoscopy examination of the heart), 
abdomen, musculoskeletal, neurological, lymph nodes, and skin (rash, injection site). Other 
body systems may be examined at the discretion of the investigator.
Note that a urinary/genital examination is not required; however, visual inspection of the 
urinary/genital area for areas of depigmentation is expected.
Height and body weight will be measured and recorded per the SoA, and will be obtained 
with the participant’s shoes off and jacket or coat removed.
Physical findings at Screening will be recorded as medical history. Abnormal findings that 
are worsening of a baseline finding or any new abnormal findings from other visits will be 
recorded as an AE.
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A brief directed physical examination will be conducted by an investigator or medically 
qualified designee (consistent with local requirements) per institutional standard at the visits 
listed in the SoA.
A physical examination (full or limited, based on investigator judgment) can be performed at 
any unscheduled visit if deemed necessary by the investigator. Investigators should pay 
special attention to clinical signs related to previous serious illnesses.
8.3.2
Vital Signs
•
Temperature, HR, RR, and BP will be assessed. The same method should be used for all 
measurements for each individual participant.
•
HR and BP measurements will be assessed in a sitting position and should be preceded 
by a few minutes of rest.
•
Vital signs are to be taken after completion of PROs and before blood collection for 
laboratory tests, except for Visit 2 (Randomization) where vital signs are collected before 
PROs as part of confirmation of eligibility.
8.3.3
Electrocardiograms
Single 12-lead ECG will be obtained and reviewed by an investigator or medically qualified 
designee (consistent with local requirements) as outlined in the SoA using an ECG machine 
that automatically calculates the HR and measures PR, QRS, QT, and QTc intervals. ECGs 
should be performed after the participant has rested quietly for at least 5 minutes. Refer to 
Appendix 10.3.2 for evaluation of potentially significant findings.
The investigator is responsible for retaining all copies of the ECG reports.
8.3.4
Clinical Safety Laboratory Assessments
Refer to Appendix 2 for the list of clinical laboratory tests to be performed and to the SoA for 
the timing and frequency.
•
The investigator or medically qualified designee (consistent with local requirements) 
must review the laboratory report, document this review, and record any clinically 
relevant changes occurring during the study in the AE section of the CRF. The laboratory 
reports must be filed with the source documents. Clinically significant abnormal 
laboratory findings are those which are not associated with the underlying disease, unless 
judged by the investigator to be more severe than expected for the participant’s condition.
•
All protocol-required laboratory assessments, as defined in Appendix 2, must be 
conducted in accordance with the Laboratory Manual and the SoA.
•
If laboratory values from nonprotocol-specified laboratory assessments performed at the 
institution’s local laboratory require a change in study participant management or are 
considered clinically significant by the investigator (eg, SAE or AE or dose 
modification), then the results must be recorded in the appropriate CRF (eg, SLAB).
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•
For any laboratory tests with values considered clinically significantly abnormal during 
participation in the study or within 28 days after the last dose of study intervention, every 
attempt should be made to perform repeat assessments until the values return to normal or 
baseline or if a new baseline is established as determined by the investigator.
8.3.5
Pregnancy Testing
Pregnancy testing:
•
Pregnancy testing requirements for study inclusion are described in Section 5.1.
•
Pregnancy testing (urine and/or serum) should be conducted as per SoA at the specified 
visits during intervention. A negative pregnancy test should be confirmed prior to 
administration of study intervention.
•
Additional serum or urine pregnancy tests may be performed, as determined necessary by 
the investigator or required by local regulation, to establish the absence of pregnancy at 
any time during the participant’s participation in the study.
See Appendix 7 for country-specific requirements.
8.3.6
TB Testing
Participants will be screened for TB using the QuantiFERON Gold Test or equivalent as 
outlined in the TB screening eligibility criterion in Section 5.2. The QuantiFERON Gold Test 
or equivalent must be performed and read by trained and licensed personnel according to 
local guidelines. If this testing was performed at any site other than the investigator’s facility, 
the results must be made available in written form as source documentation.
All participants must be evaluated for TB at Screening. The results of the TB screening must 
be interpreted in the context of the participant’s epidemiology, history, exam findings, etc,
and it is the responsibility of the investigator to determine if a participant has previous, 
active, or latent TB.
TB Testing 
•
The QFT should be performed at Screening on all participants unless the participant is 
considered to be TB test positive prior to Screening. The PPD skin test (also known as 
TB Skin Test or Mantoux Test) should be utilized when the QFT is not possible or if both 
tests are required per local guidelines. If local requirements dictate a local PPD be 
performed, this should be in addition to the QFT. 
•
Participants with documentation of prior positive results of QFT, PPD skin test, and/or 
history of latent or active TB are not required to repeat a TB test at Screening or during 
the study and should be considered TB test positive. 
•
If either PPD or QFT is positive, the TB test is considered positive. 
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•
If the QFT or PPD skin test are performed within 90 days prior to Screening and source 
documentation is available, these tests do not need to be performed at Screening,
provided nothing has changed in the participant’s medical history to warrant a repeat test.
•
If performed, the PPD should be read by a licensed healthcare professional between 48 
and 72 hours after administration. A participant who does not return within 72 hours will 
need to be rescheduled for another skin test. The PPD skin test reaction will be measured 
in millimeters (mm) of induration and induration ≥5 mm is considered a positive reaction. 
The absence of induration will be recorded as "0 mm" not "negative."
•
Participants who have had an ulcerating reaction to the PPD in the past should not be 
reexposed and the TB skin test should be considered positive.
•
If the QFT is indeterminate, the site should perform a local QFT (or through the central 
laboratory if not locally available) to rule out a positive test result. If testing remains 
indeterminate or is positive, then the participant is considered to be positive for the 
purpose of this study. If the testing result is negative, then the participant is considered to 
be negative. 
•
If TB testing is done at Screening in participants considered at low risk for TB as 
described below and a positive result is reported, the procedure for “Interpretation of a 
positive TB test in low-risk participants” should be followed OR a prior treatment for 
latent TB is required. 
Interpretation of a positive TB test in low-risk participants: In cases where the QFT by 
the central laboratory is positive and the investigator considers the participant at low risk 
for TB (ie, no risk factors identified on TB risk assessment questionnaire; see Appendix 
10) and has no clinical suspicion of TB, the investigator may perform a local QFT (or 
repeat testing through the central laboratory if not locally available) to confirm the 
positive test result. If the repeat testing result is negative, the investigator may consider 
the test to be negative based on clinical judgment. If the repeat testing is positive or 
indeterminate, the test is considered positive. 
•
An equivalent interferon Gamma Release Assay such as T-SPOT TB test may be 
substituted for the QFT.
•
TB test results will be retained at the site as the original source documentation. 
Refer to the Laboratory Manual for any additional processing information and shipping 
instructions.
8.3.7
Chest X-ray
If permitted by the local health authority and IRB/EC, a chest x-ray will be obtained as 
outlined in the SoA to screen for TB (see exclusion criterion in Section 5.2). The chest x-ray 
must be focused on identifying abnormalities suggestive of TB. Posterior-anterior chest x-ray 
is recommended; however, local guidelines should be followed (see Appendix 7 for country-
specific requirements).
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The chest x-rays must be read and assessed by a medically qualified designee. Results must 
be within normal limits or not clinically significant for enrollment in the study. The 
investigator is responsible for retaining all source documentation.
8.3.8
HBV, HCV, and HIV Testing
Participants will be screened for HBV, HCV, and HIV as outlined in the SoA. See the HBV/ 
HCV/HIV screening eligibility criterion (Section 5.2) to determine if further testing is needed 
or if the participant is eligible for the study. See Appendix 7 for country-specific 
requirements.
Hepatitis B
All participants will be tested for the presence of HBV at Screening using the following tests:
•
HBsAg (hepatitis B surface antigen)
•
HBcAb/anti-HBc (hepatitis B core antibody)
HBV serologic test results will be interpreted and managed as shown in Figure 2.
•
A positive result for HBsAg will be exclusionary.
•
A positive test result for HBcAb requires HBV-DNA PCR testing (automatic reflex 
testing) (Scenario A):
o
HBV-DNA ≥LLOQ will be exclusionary
o
A participant with HBV-DNA <LLOQ may be enrolled and the participant should 
have HBV-DNA testing performed approximately every 12 weeks (in correlation 
with a scheduled visit). If HBV-DNA is ≥LLOQ at any timepoint, the participant will 
require discontinuation of study intervention (Section 7.1). 

A negative test result for HBcAb does not require HBV-DNA PCR qualitative testing and 
the participant may be enrolled (Scenario B).
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Figure 2
Interpretation and Management of HBV Serologic Test Results
DNA=deoxyribonucleic acid, HBcAb=hepatitis B core antibody, HBsAg=hepatitis B surface antigen, HBV=hepatitis B 
virus, LLOQ=lower limit of quantification. 
a These participants should have HBV-DNA testing performed approximately every 12 weeks (in correlation with a 
scheduled visit). If HBV-DNA is ≥LLOQ at any timepoint, the participant will require discontinuation of study intervention 
(Section 7.1).
See Appendix 7 for country-specific requirements. 
8.4
Adverse Events, Serious Adverse Events, and Other Reportable Safety Events
The definitions of an AE or SAE, as well as the method of recording, evaluating, and 
assessing causality of AE and SAE and the procedures for completing and transmitting AE, 
SAE, and other reportable safety event reports can be found in Appendix 3.
Adverse events, SAEs, and other reportable safety events will be reported by the participant 
(or, when appropriate, by a caregiver, surrogate, or the participant’s legally authorized 
representative).
The investigator and any designees are responsible for detecting, documenting, and reporting 
events that meet the definition of an AE or SAE as well as other reportable safety events. 
Investigators need to document if an SAE was associated with a medication error, misuse, or 
abuse.
Investigators remain responsible for following up AEs, SAEs, and other reportable safety 
events for outcome according to Section 8.4.3. The investigator, who is a qualified physician, 
will assess events that meet the definition of an AE or SAE as well as other reportable safety 
events with respect to seriousness, intensity/toxicity, and causality.
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8.4.1
Time Period and Frequency for Collecting AE, SAE, and Other Reportable 
Safety Event Information
All AEs, SAEs, and other reportable safety events that occur after the participant provides 
documented informed consent, but before intervention randomization, must be reported by 
the investigator if the participant is receiving placebo run-in or other run-in treatment; if the 
event causes the participant to be excluded from the study, or is the result of a protocol-
specified intervention, including, but not limited to washout or discontinuation of usual 
therapy, diet, or a procedure.
From the time of intervention randomization through 28 days after cessation of treatment, all 
AEs, SAEs, and other reportable safety events must be reported by the investigator.
Additionally, any SAE brought to the attention of an investigator at any time outside the 
period specified in the previous paragraph must be reported immediately to the Sponsor if the 
event is considered related to study intervention.
Investigators are not obligated to actively seek AEs or SAEs or other reportable safety events 
in former study participants. However, if the investigator learns of any SAE, including a 
death, at any time after a participant has been discharged from the study, and the investigator 
considers the event to be reasonably related to the study intervention or study participation, 
the investigator must promptly notify the Sponsor.
All initial and follow-up AEs, SAEs, and other reportable safety events will be recorded and 
reported to the Sponsor or designee within the time frames as indicated in Table 3.
Exception: A positive pregnancy test at the time of initial screening is not a reportable event 
unless the participant has received study intervention.
Table 3
Reporting Periods and Time Frames for Adverse Events and Other Reportable 
Safety Events
Type of Event
Reporting Period:
Consent to 
Randomization/
Allocation
Reporting Period:
Randomization/
Allocation 
Through 
Protocol-specified 
Follow-up Period
Reporting 
Period:
After the 
Protocol-
specified 
Follow-up 
Period
Time Frame 
to Report 
Event and 
Follow-up 
Information to 
Sponsor
NSAE
Report if:
– due to protocol-
specified 
intervention
– causes exclusion
– participant is 
receiving placebo 
run-in or other run-
in treatment
Report all
Not required
Per data entry 
guidelines
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Type of Event
Reporting Period:
Consent to 
Randomization/
Allocation
Reporting Period:
Randomization/
Allocation 
Through 
Protocol-specified 
Follow-up Period
Reporting 
Period:
After the 
Protocol-
specified 
Follow-up 
Period
Time Frame 
to Report 
Event and 
Follow-up 
Information to 
Sponsor
SAE
Report if:
– due to protocol-
specified 
intervention
– causes exclusion
– participant is 
receiving placebo 
run-in or other run-
in treatment
Report all
Report if:
– drug/vaccine 
related.
(Follow 
ongoing to 
outcome)
Within 
24 hours of 
learning of 
event
Pregnancy/Lactation 
Exposure
Report if:
– participant has been 
exposed to any 
protocol-specified 
intervention (eg, 
procedure, washout,
or run-in treatment 
including placebo 
run-in)
Exception: A positive 
pregnancy test at the 
time of initial 
screening is not a 
reportable event.
Report all
Previously 
reported –
Follow to 
completion/
termination; 
report outcome
Within 
24 hours of 
learning of 
event
ECI (requiring
regulatory reporting)
Report if:
– due to intervention
– causes exclusion
Report
– potential DILI
– requiring
regulatory 
reporting
Not required
Within 
24 hours of 
learning of 
event
ECI (does not require 
regulatory reporting)
Report if:
– due to intervention
– causes exclusion
Report
– non-DILI ECIs 
and those not 
requiring 
regulatory 
reporting
Not required
Within 
5 calendar days 
of learning of 
event
Cancer
Report if:
– due to intervention
– causes exclusion
Report all
Not required
Within 
5 calendar days 
of learning of 
event (unless 
serious)
Overdose
Report if:
– receiving placebo 
run-in or other run-
in medication 
Report all
Not required
Within 
5 calendar days 
of learning of 
event
DILI=drug-induced liver injury; ECI=event of clinical interest; NSAE=nonserious adverse event; SAE=serious 
adverse event.
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8.4.2
Method of Detecting AEs, SAEs, and Other Reportable Safety Events
Care will be taken not to introduce bias when detecting AEs and/or SAEs and other 
reportable safety events. Open-ended and nonleading verbal questioning of the participant is 
the preferred method to inquire about AE occurrence.
8.4.3
Follow-up of AE, SAE, and Other Reportable Safety Event Information
After the initial AE/SAE report, the investigator is required to proactively follow each 
participant at subsequent visits/contacts. All AEs, SAEs, and other reportable safety events, 
including pregnancy and exposure during breastfeeding, ECIs, cancer, and overdose will be 
followed until resolution, stabilization, until the event is otherwise explained, or the 
participant is lost to follow-up (as defined in Section 7.3). In addition, the investigator will 
make every attempt to follow all nonserious AEs that occur in randomized participants for 
outcome. Further information on follow-up procedures is given in Appendix 3.
8.4.4
Regulatory Reporting Requirements for SAE
Prompt notification (within 24 hours) by the investigator to the Sponsor of 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 and global laws and 
regulations relating to safety reporting to regulatory authorities, IRB/IECs, and investigators.
Investigator safety reports must be prepared for SUSARs according to local regulatory 
requirements and Sponsor policy and forwarded to investigators as necessary.
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 file it 
along with the IB and will notify the IRB/IEC, if appropriate according to local requirements.
8.4.5
Pregnancy and Exposure During Breastfeeding
Although pregnancy and infant exposure during breastfeeding are not considered AEs, any 
pregnancy or infant exposure during breastfeeding (spontaneously reported to the 
investigator or their designee) that occurs in a participant during the study are reportable to 
the Sponsor.
All reported pregnancies must be followed to the completion/termination of the pregnancy. 
Any pregnancy complication will be reported as an AE or SAE.
The medical reason (example: maternal health or fetal disease) for an elective termination of 
a pregnancy will be reported as an AE or SAE. Prenatal testing showing fetus will be born 
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with severe abnormalities/congenital anomalies that leads to an elective termination of a 
pregnancy will be reported as an SAE for the fetus.
Pregnancy outcomes of ectopic pregnancy, spontaneous abortion, missed abortion, benign 
hydatidiform mole, blighted ovum, fetal death, intrauterine death, miscarriage, and stillbirth 
must be reported as serious events (Important Medical Events). If the pregnancy continues to 
term, the outcome (health of infant) must also be reported.
8.4.6
Disease-related Events and/or Disease-related Outcomes Not Qualifying as 
AEs or SAEs
Not applicable
8.4.7
Events of Clinical Interest
Selected serious and nonserious AEs are also known as ECIs and must be reported to the 
Sponsor.
Events of clinical interest for this study include:
1. Potential DILI events defined as an elevated AST or ALT laboratory value that is greater 
than or equal to 3× the ULN and an elevated total bilirubin laboratory value that is greater 
than or equal to 2× the ULN and, at the same time, an alkaline phosphatase laboratory 
value that is less than 2× the ULN, as determined by way of protocol-specified laboratory 
testing or unscheduled laboratory testing.*
*Note: These criteria are based on available regulatory guidance documents. The purpose 
of the criteria is to specify a threshold of abnormal hepatic tests that may require an 
additional evaluation for an underlying etiology. The study-site guidance for assessment 
and follow-up of these criteria can be found in the Investigator Study File Binder (or 
equivalent).
2. AEC >5000 cells/µL at a single time point
3. AEC >1500 cells/µL and confirmed or suspected hypereosinophilic syndrome or 
eosinophil-associated organ injury; see Appendix 9 for definitions and examples.
8.4.8
Drug-device Combination Products/Combination Medicinal Products –
Complaints, PQCs, and Malfunctions
The method of documenting and reporting complaints, PQCs, and malfunctions will occur as 
below and in Appendix 4. Refer to Appendix 7 for country-specific information and 
definitions.
To fulfill regulatory reporting obligations worldwide, medical device information associated 
with AEs will be collected and reported to the Sponsor in the same time frame as AEs per 
Section 8.4.1 via CRF (paper or electronic) and as per data entry guidelines.
All SAEs due to malfunction will be followed until resolution, stabilization, until the event is 
otherwise explained, or the participant or associated person is lost to follow-up.
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PQCs/malfunctions, including those that involve a participant or any user/associated person, 
must be reported to the Sponsor. Sponsor shall review reported events by the investigator to 
fulfill the legal responsibility of notifying appropriate regulatory authorities and other entities 
about certain safety information relating to the drug-device combination 
products/combination medicinal products being used in clinical studies.
The investigator is responsible for ensuring that follow-up includes any supplemental 
investigations as indicated to elucidate the nature and/or causality between the AE and the 
device constituent of combination product.
8.5
Treatment of Overdose
For purposes of this study, an overdose will be defined as 2 or more doses of study 
intervention administered <10 days apart.
If an overdose occurs, a CBC with differential to assess absolute eosinophil counts (see 
Section 6.6.3 and Appendix 9) must be performed prior to the next dose of study 
intervention. If the overdose is associated with an AE, the participant should have the CBC 
with differential performed as soon as possible.
8.6
Pharmacokinetics
The decision as to which serum samples collected will be measured for evaluation of PK will 
be collaboratively determined by the Sponsor. If indicated, these samples may also be 
assayed and/or pooled for assay in an exploratory manner for additional PD markers. Blood 
samples collected may be stored and further analysis may be performed, if required.
Samples for PK and ADA should be drawn at the same time prior to study intervention 
administration.
At Visit 3 (1 day after Randomization) and Visit 8 (1 day after the Week 12 visit), all 
participants will come to the study site for blood collection (24 hours [±12 hours] after study 
intervention administration) as outlined in the SoA.
8.6.1
Blood Collection for Serum MK-6194
Sample collection, storage, and shipment instructions for serum samples are provided in the 
Laboratory Manual.
8.7
Pharmacodynamics
Sample collection, storage, and shipment instructions for pharmacodynamic samples are 
provided in Laboratory Manual. Blood samples collected may be stored and further analysis 
may be performed, if required.
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8.7.1
Immunogenicity Assessments
Samples for ADA analysis will be collected prior to study intervention administration at the
timepoints specified in the SoA. Samples for ADA and PK should be drawn at the same time. 
Confirmed ADA samples will be assayed for titer. Other assays for neutralizing antibodies, 
ADA domain mapping and cross-reactivity to WT-IL-2 may be performed. Sample 
collection, storage, and shipment instructions for serum samples are provided in the 
Laboratory Manual.
8.7.2
Immunophenotyping
Blood for immunophenotyping will be collected for all participants as outlined in the SoA 
Section 1.3. Additional samples will be collected from participants that are part of the 
PK/PD/Biomarker Subpopulation as outlined in Section 1.3.3.
Blood collected for immunophenotyping will be assessed using the Treg -
immunophenotyping assay and TBNK assay. For all participants, blood will be collected for 
use in the TBNK assay. For participants in the Subpopulation, blood will be collected to use 
in both Treg-immunophenotyping and TBNK assays.
8.8
Biomarkers
The following samples for biomarker research will be collected from participants prior to 
study intervention administration as specified in the SoA:
•
Blood for genetic analysis
•
Blood for immunophenotyping
•
Blood for PBMC biomarkers
•
Blood for serum biomarkers analysis
•
Blood for DNA biomarkers analysis
•
Blood for RNA biomarkers analysis
Sample collection, storage, and shipment instructions for biomarker samples are provided in 
the Laboratory Manual.
8.8.1
Planned Genetic Analysis Sample Collection
The planned genetic analysis sample should be drawn for planned analysis of the association 
between genetic variants in DNA and drug response. This sample will not be collected at the 
site if there is either a local law or regulation prohibiting collection, or if the IRB/IEC does 
not approve the collection of the sample for these purposes. If the sample is collected, 
leftover extracted DNA will be stored for FBR if the participant provides documented 
informed consent for FBR. If the planned genetic analysis is not approved, but FBR is 
approved and consent is given, this sample will be collected for the purpose of FBR.
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The planned genetic analysis sample should be obtained predose on Day 1, but may be 
collected at the next scheduled blood draw, if needed. Sample collection, storage, and 
shipment instructions for planned genetic analysis samples will be in the Laboratory Manual.
8.9
Future Biomedical Research Sample Collection
If the participant provides documented informed consent for FBR, the following specimens 
will be obtained as part of FBR:
•
Leftover samples listed in Section 8.8, except for blood for immunophenotyping
8.10
Visit Requirements
Visit requirements are outlined in Section 1.3. Specific procedure-related details are provided 
in Section 8.
Scheduling Visits
A visit should occur within the recommended scheduling window shown in the SoA. Study 
visits that include study intervention dispensation (Section 1.3) should be scheduled at least 
10 days apart to avoid overdose (Section 8.5).
Unscheduled Visits are allowed whenever necessary.
Except for Visit 2, all PROs should be completed in the order listed in the SoA before
laboratory tests or any other efficacy or safety procedures (Section 8.2.1).
8.10.1
Screening/Rescreening Visits
Screening
Up to 4 weeks before intervention randomization, potential participants will be evaluated to 
determine whether they fulfill the entry requirements as set forth in Section 5.
Rescreening
Participants are allowed to rescreen once. Participants who are rescreened will retain the 
original screening number assigned at the initial Screening Visit (Section 8.1.6). Once a 
participant has started the rescreening process, a new screening period will begin (ie, an 
additional 4-week window) during which time screening procedures will be repeated. If the 
participant’s original screening laboratory results and procedures were not exclusionary and 
rescreening is completed within 4 weeks of the initial Screening Visit date, the screening 
laboratory assessments or procedures do not need to be repeated.
If the informed consent has been updated, participants must be reconsented before 
rescreening. If no updates have been made, the informed consent from the original screening 
period should be reviewed with the participant and a verbal reconsent to continue in the study 
should be documented.
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8.10.2
Double-Blind Treatment Period
Each visit should be performed as specified in the SoA.
Participants who satisfy all entry criteria will be randomized (via IRT) to double-blind study 
intervention at Visit 2 (Day 1). Participants will complete PROs in the order listed in the SoA 
and specified in Section 8.2.1, before any other procedures are completed, except for Visit 2 
(Randomization) where PROs can be completed after confirming eligibility.
Participants will be educated by a trained member of the site staff on appropriate 
administration of study intervention (Section 8.1.9.3). The first dose of study intervention 
will be witnessed by a member of the site staff in the clinic after completion of all other 
study procedures (Section 8.1.9.4). Witnessed dosing will occur at visits outlined in the SoA.
Week 24 Visit
At Visit 10 (Week 24), all procedures for the Double-Blind Treatment Period (Section 1.3.1) 
need to be completed BEFORE the Week 24 study intervention administration as the Week 
24 dosing will be part of the Blinded Extension Period (Section 1.3.2).
8.10.3
Blinded Extension Period
The Blinded Extension Period begins with the participant’s Week 24 administration of study 
intervention. Study procedures are outlined in Section 1.3.2. Participants who were assigned 
to the placebo group during the Double-Blind Treatment Period will be rerandomized to an 
active arm as outlined in Section 6.3.1.
Participants who permanently discontinued study intervention will continue to be monitored 
in the study according to the parameters outlined in Section 8.10.5.
8.10.4
PK/PD/Biomarker Subpopulation Visits
At selected sites, additional PK/PD/Biomarker samples will be collected from participants 
who consent as outlined in the SoA (Section 1.3.3) in addition to the activities listed in the 
Double-Blind Treatment and Blinded Extension Periods (Sections 1.3.1 and 1.3.2).
During Visit 2, an additional PK sample will be collected 2 to 10 hours after study 
intervention administration. Participants will need to remain at, or come back to, the site to 
have this sample collected. If the PK sample is not able to be collected at Visit 2, then the 
sample will be collected 2 to 10 hours after study intervention administration at Visit 7.
Participants who discontinue study intervention will no longer be part of this Subpopulation.
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8.10.5
Participants Discontinued From Study Intervention but Continuing to be 
Monitored in the Study
Any participant who prematurely discontinues study intervention will have a Discontinuation 
Visit as outlined in the SoA (Section 1.3). Participants will be encouraged to continue their 
participation in the study off study intervention until the end of the study period in which 
they discontinued, and be followed for all remaining study visits in that period (Section 7.1) 
as outlined in the SoA with the following exceptions, which are not applicable after study 
intervention is discontinued.
•
Efficacy data, including photographs
•
PK, PD, Biomarker sample collection
•
Study intervention dispense/return
•
Witnessed dose
•
Train/retrain participant on self-administration
•
Dosing reminder telephone call
Discontinuation Visit assessments should be performed at the time of discontinuation. Any 
AEs present at the time of discontinuation should be followed in accordance with the safety 
requirements outlined in Section 8.4.
Concomitant therapies specifically prohibited (see Section 6.5, [Table 1], and Appendix 8) 
while the participant was on study intervention are no longer prohibited after discontinuation 
of study intervention, except for live vaccines. See Appendix 7 for country-specific
requirements.
Note: At the Discontinuation Visit, IRT will be contacted for closeout purposes.
8.10.6
Follow-up Telephone Call
Participants will be contacted at least 28 days (+7 days) after the last administration of study 
intervention to determine if any AEs have occurred since discontinuing study intervention. 
During this telephone call, AE and concomitant medication information will be collected.
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9
KEY STATISTICAL CONSIDERATIONS
This section outlines the statistical analysis strategy and procedures for the study. If, after the 
study has begun, but prior to any unblinding, there are changes made to the primary 
hypothesis, or the statistical methods related, then the protocol will be amended (consistent 
with ICH Guidance for Industry E9). Changes to non-confirmatory analyses made after the 
protocol has been finalized, but prior to unblinding will be documented in a SAP and 
referenced in the CSR for the study. Post-hoc exploratory analyses will be clearly identified 
in the CSR. Separate analysis plans (ie, separate documents from the SAP) will be developed 
to detail other planned analyses including those specific to the analysis of PK data.
9.1
Responsibility for Analyses/In-house Blinding
The statistical analysis of the data obtained from this study will be the responsibility of the 
Sponsor.
This study will be conducted as a double-blind study under in-house blinding procedures. 
The official, final database for the Double-Blind Treatment Period (at Week 24) will not be 
unblinded until medical/scientific review has been performed, protocol deviations have been 
identified, and data have been declared final and complete. Only the clinical database and 
sponsor personnel directly involved in the Week 24 analysis and reporting will become 
unblinded at the time of the Week 24 database lock.
The extension period of this study will also be conducted as a blinded study. The database of 
the extension period will be unblinded after the end of the Blinded Extension Period (Week 
52). Additional efficacy and safety analyses will be performed based on the data acquired 
from the completion of the extension period.
The Biostatistics and Research Decision Sciences department will generate the randomized 
allocation schedule(s) for study treatment assignment.
9.2
Hypotheses/Estimation
Objectives and hypotheses of the study are stated in Section 3.
9.3
Analysis Endpoints
Efficacy and safety endpoints that will be evaluated for within- and/or between-treatment
differences are listed below.
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9.3.1
Efficacy Endpoints
Primary Efficacy Endpoint

Percent change from baseline in F-VASI at Week 24
Secondary Efficacy Endpoint

Percent change from baseline in T-VASI at Week 24
Exploratory Efficacy Endpoints
Exploratory efficacy endpoints are stated in Section 3 of the protocol.
9.3.2
Safety Endpoints
Safety endpoints are stated in Section 3 of the protocol. 
Safety and tolerability will be assessed by clinical review of all relevant parameters including 
adverse events, laboratory values, and vital signs.
9.4
Analysis Populations
9.4.1
Efficacy Analysis Population
The FAS population will serve as the primary population for the efficacy data analysis. The 
FAS population consists of all randomized participants who received at least one injection of 
study intervention. Participants will be analyzed by the treatment group assigned at 
randomization.
9.4.2
Safety Analysis Population
The APaT population will be used for the safety data analysis. The APaT population consists 
of all randomized/allocated participants who received at least one injection of study 
intervention. Participants will be analyzed in the treatment arm actually received.
9.4.3
Pharmacokinetic Analysis Population
The population for PK data analysis will include all participants with at least 1 measurable 
PK sample after treatment with MK-6194. 
9.4.4
Pharmacodynamic Analysis Population 
The population for the PD endpoints will be the FAS population. All randomized participants 
who have at least 1 injection (including partial injection) of study intervention and have at 
least 1 assessment for those analyses for which this is required will be included in this 
population. 
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9.4.5
Immunogenicity Analysis Population 
The population for immunogenicity analysis will include all participants with at least 1 ADA 
assay result after treatment with MK-6194.
9.5
Statistical Methods
9.5.1
Estimand(s)
Estimand for the Primary Efficacy Analysis
The estimand for the primary objective of this study contains 5 attributes:

Treatment Regimen: MK-6194 or matching placebo

Target population: Adult Participants with Non-Segmental Vitiligo

Endpoint: The percent change from baseline in F-VASI at Week 24

The population-level summary: the difference in the mean percent change from baseline 
in F-VASI at Week 24 between the treatment group and placebo

Intercurrent events:  Detailed below:
Number
Intercurrent Events
Handling Strategy
Intercurrent Event #1
Discontinuation of MK-6194 or placebo
Treatment Policy 
Strategy
Intercurrent Event #2
Usage of any medication for the treatment 
of Vitiligo as listed in Protocol Section 5.2 
# 19
Treatment Policy 
Strategy
9.5.2
Statistical Methods for Efficacy Analyses
All efficacy endpoints will be analyzed based on the FAS population. Unless otherwise 
specified, all efficacy data will be included in efficacy analyses. A Hochberg testing 
procedure will be implemented in this study for multiplicity adjustment. LDA method will be 
used for the analysis of the continuous endpoints, and stratified M&N method will be used 
for the analysis of the binary endpoints.
Primary Efficacy Analysis
The primary endpoints, the percent change from baseline in F-VASI score at Week 24, will 
be analyzed using a LDA model for repeated measures. This model will use all available data 
on F-VASI at baseline and all post-baseline timepoints. In this model, time will be treated as 
a categorical variable so that no restriction is imposed on the trajectory of the means over 
time. The analysis model will adjust for treatment, visit, treatment by visit, and baseline 
vitiligo status (stable, active) and previous JAK inhibitor use (yes, no). Point estimates, 95% 
CI and p-value for the treatment differences will be provided. If there are a small number of 
responses in one or more strata, for the purpose of analysis, strata will be combined to ensure 
a sufficient number of participants and responses in each stratum. Details regarding the 
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combining of strata will be specified in the SAP prior to database lock based on a blinded 
review of response by stratum. An unstructured covariance matrix will be used to model the 
correlation among repeated measurements.
Sensitivity Analyses
In addition to the analysis approach specified above for the primary endpoint analysis 
section, the following sensitivity analyses will be used to assess the robustness of the primary 
analysis approach.
Multiple-imputation Analysis
For all participants with missing baseline F-VASI assessment, single imputation (only once)
will be implemented based on baseline stratification factors. All post-baseline missing F-
VASI assessments will be handled using multiple imputation (MI) under the missing-at-
random (MAR) assumption.
Tipping-point Multiple-imputation Analysis
Tipping point as described in Ratitch et al. (2013) [Ratitch, B., et al 2013] will be conducted. 
In this approach, missing data are first imputed for all visits under the MAR assumption, and 
then the worsening/shift is applied.  This is repeated with increasing the delta-shift 
(worsening) until the result is no longer statistically significant. 
Secondary Efficacy Analysis
The secondary efficacy endpoint, the percent change from baseline in T-VASI at Week 24, 
will be analyzed similarly as the primary endpoint.
Table 4
Analysis Strategy for Key Efficacy Variables
Endpoint/Variable
(Description, Time Point)
Primary vs 
Supportive 
Approach
Statistical 
Method
Analysis 
Population
Missing Data 
Approach
Primary Endpoint/Hypothesis 1
Percent change from baseline in 
F-VASI at Week 24
P
LDA
FAS
Model based 
S
LDA
FAS
Multiple Imputation
S
LDA
FAS
Tipping Point 
Multiple Imputation
Secondary Endpoint 2
Percent change from baseline in 
T-VASI at Week 24
P
LDA
FAS
Model based
FAS=Full Analysis Set; F-VASI= Facial Vitiligo Area Scoring Index; LDA=longitudinal data analysis; MI=multiple 
imputation; P=Primary approach; S=Supportive approach; T-VASI= Total Vitiligo Area Scoring Index.
The efficacy analysis mentioned above will be performed at the end of the Double-Blind 
Treatment Period (Week 24). Additional descriptive analyses will be performed at the end of 
the Blinded Extension Period (Week 52). Details of the analysis plan will be finalized in the 
SAP before the final database lock.
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9.5.3
Statistical Methods for Safety Analyses
Safety and tolerability will be assessed by clinical review of AEs and other relevant 
parameters, including laboratory tests, and vital signs.
The overall safety evaluation will include a summary (ie, frequency and percentage) by 
treatment group of participants with at least one AE, drug-related AE, serious AE, serious 
drug-related AE, discontinuation from study intervention due to an AE, and AE resulting in 
death.
Point estimates and 95% CIs of the differences between treatment groups in the percentages 
of participants with events will be provided using the M&N method [Miettinen, O. and 
Nurminen, M. 1985]. Figures and/or plots will be provided as needed.
For continuous safety measures, such as change from baseline in laboratory, and vital signs, 
summary statistics for baseline, on-treatment, and change from baseline values will be 
provided by treatment group.
Table 5 summarizes analysis strategy for safety endpoints in this study. 
Table 5
Analysis Strategy for Safety Parameters
Safety Endpoint
Descriptive 
Statistics
95% Between-
group CI
Graphical 
Display
Any AE
X
X
Any serious AE
X
X
Any drug-related AE
X
X
Any serious drug-related AE
X
X
Discontinued study treatment due to AE 
X
X
AE that resulted in death
X
Specific AEs or SOCs (incidence ≥ 4
participants in any treatment group)
X
Xa
Xa
Change from Baseline Results (Labs, Vital 
Signs)
X
AE=adverse event; CI=Confidence Interval; SOC=System Organ Class.
a: Threshold for incidence will be applied for CI and Graphical Display.
The safety analysis mentioned above will be performed at the end of the Double-Blind 
Treatment Period (Week 24). Additional descriptive analyses will be performed at the end of 
the Blinded Extension Period (Week 52). Details of the analysis plan will be finalized in the 
SAP before the final database lock.
9.6
Interim Analyses
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9.7
Multiplicity
Due to the interim analysis for futility, an α-spending of 0.0001 will be applied to the 2-sided 
Type I error rate of 5% for the primary hypothesis based on the Haybittle-Peto method 
[Haybittle, J. L. 1971] [Peto, R., et al 1976]. Multiplicity adjustment will be made for testing
2 doses on the primary endpoint for the analysis, i.e., for testing a family of the following 
hypotheses: 

H1(1): 3 mg MK-6194 Q4W dose is superior to placebo in the percent change from 
baseline in F-VASI at Week 24. 

H1(2): 3 mg MK-6194 Q2W dose is superior to placebo in the percent change from 
baseline in F-VASI at Week 24. 
To strongly control the Type-I error rate for this family, the Hochberg procedure [Hochberg, 
Y. 1988] will be applied.
9.8
Sample Size and Power Calculations
This study will randomize 55 participants into each treatment group and has >80% power to 
demonstrate the superiority of at least 1 dose of MK-6194 over placebo at an overall 2-sided 
0.0499 alpha-level, if the underlying treatment difference in percent change from baseline at 
Week 24 in F-VASI score is -20%. The power and sample size are based on the following 
assumptions: 1) a 15% drop out rate, 2) a standard deviation of 33%, pooled across treatment 
groups. 
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10
SUPPORTING DOCUMENTATION AND OPERATIONAL CONSIDERATIONS
10.1
Appendix 1: Regulatory, Ethical, and Study Oversight Considerations
10.1.1
Code of Conduct for Interventional Clinical Trials
Merck Sharp & Dohme LLC, Rahway, NJ, USA (MSD)
I.
Introduction
A. Purpose
Merck Sharp & Dohme LLC, Rahway, NJ, USA (MSD), through its subsidiaries, 
conducts clinical trials worldwide to evaluate the safety and effectiveness of our 
products. As such, we are committed to designing, planning, conducting, analyzing, 
and reporting these trials in compliance with the highest ethical and scientific 
standards. Protection of participants in clinical trials is the overriding concern in the 
design and conduct of clinical trials. In all cases, MSD clinical trials will be 
conducted in compliance with MSD’s global standards, local and/or national 
regulations (including all applicable data protection laws and regulations), Regulation 
(EU) 536/2014, the International Council for Harmonisation Good Clinical Practice 
(ICH GCP) E6 and ICH General Considerations for Clinical Studies E8, and in 
accordance with the ethical principles that have their origin in the Declaration of 
Helsinki.
B. Scope
Highest ethical and scientific standards shall be endorsed for all clinical 
interventional investigations sponsored by MSD irrespective of the party (parties) 
employed for their execution (e.g., contract research organizations, collaborative 
research efforts). This Code is not intended to apply to trials that are observational in 
nature, or which are retrospective. Further, this Code does not apply to investigator-
initiated trials, which are not under the full control of MSD.
II. Scientific Issues
A. Trial Conduct
1. Trial Design
Except for pilot or estimation trials, clinical trial protocols will be hypothesis-
driven to assess safety, efficacy, and/or pharmacokinetic or pharmacodynamic 
indices of MSD or comparator products. Alternatively, MSD may conduct 
outcomes research trials, trials to assess or validate various endpoint measures, or 
trials to determine patient preferences, etc.
The design (i.e., participant population, duration, statistical power) must be 
adequate to address the specific purpose of the trial and shall respect the data 
protection rights of all participants, trial site staff and, where applicable, third 
parties. Input may be considered from a broad range of stakeholders, including 
patient advocacy groups/patients representing the trial population, caregivers, and 
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healthcare providers to ensure operational feasibility. Trial design also includes 
proactive identification of critical to quality factors utilizing a risk-based 
approach. Plans are then developed to assess and mitigate risks to those factors as 
appropriate during the trial. All trial protocols are and will be assessed for the 
need and capability to enroll underrepresented groups. Participants must meet 
protocol entry criteria to be enrolled in the trial.
2. Site Selection
MSD’s clinical trials are conducted globally in many different countries and in 
diverse populations, including people of varying age, race, ethnicity, gender, and 
accounting for other potential disease related factors. MSD selects investigative 
sites based on medical expertise, access to appropriate participants, adequacy of 
facilities and staff, previous performance in clinical trials, as well as budgetary 
considerations. Prior to trial initiation, sites are evaluated by MSD personnel (or 
individuals acting on behalf of MSD) to assess the ability to successfully conduct 
the trial. Individuals involved in trial conduct receive training commensurate with 
their role prior to their becoming involved in the trial.
Where appropriate, and in accordance with regulatory authority guidance, MSD 
will make concerted efforts to raise awareness of clinical trial opportunities in 
various communities. MSD will seek to engage underrepresented groups and 
those disproportionately impacted by the disease under study. MSD will support 
clinical trial investigators to enroll underrepresented groups and expand access to 
those who will ultimately use the products under investigation.
3. Site Monitoring/Scientific Integrity
Investigative trial sites are monitored to assess compliance with the trial protocol 
and Good Clinical Practice (GCP). MSD reviews clinical data for accuracy, 
completeness, and consistency. Data are verified versus source documentation 
according to standard operating procedures. Per MSD policies and procedures, if 
potential fraud, scientific/research misconduct, privacy incidents/breaches or 
Clinical Trial-related Significant Quality Issues are reported, such matters are 
investigated. When necessary, appropriate corrective and/or preventative actions 
are defined and regulatory authorities and/or ethics review committees are 
notified.
B. Publication and Authorship
Regardless of trial outcome, MSD commits to publish the primary and secondary 
results of its registered trials of marketed products in which treatment is assigned, 
according to the pre-specified plans for data analysis. To the extent scientifically 
appropriate, MSD seeks to publish the results of other analyses it conducts that are 
important to patients, physicians, and payers. Some early phase or pilot trials are 
intended to be hypothesis generating rather than hypothesis testing; in such cases, 
publication of results may not be appropriate since the trial may be underpowered and 
the analyses complicated by statistical issues such as multiplicity.
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MSD’s policy on authorship is consistent with the recommendations published by the 
International Committee of Medical Journal Editors (ICMJE). In summary, 
authorship should reflect significant contribution to the design and conduct of the 
trial, performance or interpretation of the analysis, and/or writing of the manuscript. 
All named authors must be able to defend the trial results and conclusions. MSD 
funding of a trial will be acknowledged in publications.
III.Participant Protection
A. Regulatory Authority and Ethics Committee Review (Institutional Review Board 
[IRB]/Independent Ethics Committee [IEC])
All protocols and protocol amendments will be submitted by MSD for regulatory 
authority acceptance/authorization prior to implementation of the trial or amendment, 
in compliance with local and/or national regulations.
The protocol, protocol amendment(s), informed consent form, investigator’s 
brochure, and other relevant trial documents must be reviewed and approved by an 
IRB/IEC before being implemented at each site, in compliance with local and/or 
national regulations and ICH Guidelines. Changes to the protocol that are required 
urgently to eliminate an immediate hazard and to protect participant safety may be 
enacted in anticipation of ethics committee approval. MSD will inform regulatory 
authorities of such new measures to protect participant safety, in compliance with 
local and/or national regulations.
B. Safety
The guiding principle in decision-making in clinical trials is that participant welfare is 
of primary importance. Potential participants will be informed of the risks and 
benefits of, as well as alternatives to, trial participation. At a minimum, trial designs 
will take into account the local standard of care.
All participation in MSD clinical trials is voluntary. Participants enter the trial only 
after informed consent is obtained. Trial designs include procedures and systems for 
the identification, monitoring, and reporting of safety concerns. Participants may 
withdraw from an MSD trial at any time, without any influence on their access to, or 
receipt of, medical care that may otherwise be available to them.
During trial planning, the need for an independent Data Monitoring Committee 
(DMC) is assessed. DMC review of data accumulated during the conduct of the trial 
is integral to the well-being of trial participants.
C. Confidentiality
MSD is committed to safeguarding participant confidentiality, to the greatest extent 
possible, as well as all applicable data protection rights. Unless required by law, only 
the investigator, Sponsor (or individuals acting on behalf of MSD), ethics committee, 
and/or regulatory authorities will have access to confidential medical records that 
might identify the participant by name.
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D. Genomic Research
Genomic research will only be conducted in accordance with a protocol and informed 
consent authorized by an ethics committee.
E. Trial Results
At the time of providing informed consent and in accordance with local laws and 
regulations, participants should be informed about the plans for availability of trial 
results.
IV.Financial Considerations
A. Payments to Investigators
Clinical trials are time- and labor-intensive. It is MSD’s policy to compensate 
investigators (or the sponsoring institution) in a fair manner for the work performed 
in support of MSD trials. MSD does not pay incentives to enroll participants in its 
trials. However, when enrollment is particularly challenging, additional payments 
may be made to compensate for the time spent in extra recruiting efforts.
MSD does not pay for participant referrals. However, MSD may compensate 
referring physicians for time spent on medical record review and medical evaluation 
to identify potentially eligible participants.
B. Clinical Research Funding
Informed consent forms will disclose that the trial is sponsored by MSD, and that the 
investigator or sponsoring institution is being paid or provided a grant for performing 
the trial. However, the local ethics committee may wish to alter the wording of the 
disclosure statement to be consistent with financial practices at that institution. As 
noted above, all publications resulting from MSD trials will indicate MSD as a source 
of funding.
C. Funding for Travel and Other Requests
Funding of travel by investigators and support staff (e.g., to scientific meetings, 
investigator meetings, etc) will be consistent with local guidelines and practices.
V. Investigator Commitment
Investigators will be expected to review MSD’s Code of Conduct as an appendix to the 
trial protocol, and in signing the protocol, agree to support these ethical and scientific 
standards.
10.1.2
Financial Disclosure
Financial disclosure requirements are outlined in the US Food and Drug Administration 
Regulations, Financial Disclosure by Clinical Investigators (21 CFR Part 54). It is the 
Sponsor’s responsibility to determine, based on these regulations, whether a request for 
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financial disclosure information is required. It is the investigator’s/subinvestigator’s 
responsibility to comply with any such request.
The investigator/subinvestigator(s) agree, if requested by the Sponsor in accordance with 21 
CFR Part 54, to provide their financial interests in and/or arrangements with the Sponsor to 
allow for the submission of complete and accurate certification and disclosure statements. 
The investigator/subinvestigator(s) further agree to provide this information on a 
Certification/Disclosure Form, frequently known as a financial disclosure form, provided by 
the Sponsor. The investigator/subinvestigator(s) also consent to the transmission of this 
information to the Sponsor in the United States for these purposes. This may involve the 
transmission of information to countries that do not have laws protecting personal data.
10.1.3
Data Protection
The Sponsor will conduct this study in compliance with all applicable data protection 
regulations.
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 that would make the participant identifiable will not be transferred.
The participant must be informed that their 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.
The participant must be informed that their 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.
Pursuant to Union law (Clinical Trials Directive 2001/20/EC and Clinical Trials Regulation 
536/2014), the Investigator is responsible for pseudonymizing and assigning a key-
code/patient ID to each study subject.  In addition, the Investigator is required by Union law 
to store the Key (linking the Patient ID to the full name of the study subject) at the site in the 
EU/EEA throughout the course of the study and for a designated period of time thereafter.  
Finally, the study site is only permitted to share pseudonymized study subject personal data 
with the Sponsor.  
The European Data Protection Board, in its Recommendations 01/2020 on measures that 
supplement transfer tools to ensure compliance with the EU level of protection of personal 
data (“Recommendations”), states in Paragraph 85 that pseudonymization (of study subject) 
personal data under the conditions described above constitutes an effective supplemental 
measure.  
Organizational measures are contractually imposed on third party vendors wherever possible, 
to ensure that Personal Data are protected by industry-best practices against accidental
destruction or loss (physical/logical) which include regular backup procedures, Firewalls, and 
disaster recovery plans.
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In support of Corporate Policy 1 Information Risk Management, on a Sponsor-wide basis all 
supplier relationships, both IT and non-IT related, are strongly encouraged to meet the 
Sponsor’s Supplier Information Risk Management Standard.  To protect the confidentiality, 
availability and integrity of Sponsor information, conformity to information risk 
requirements by supplier personnel, hardware and software may be measured, analyzed and 
appropriate corrective/preventive actions taken as necessary. Based on the supplier criticality, 
additional activities (e.g., on-site reviews, integrated business continuity exercises) may be 
required to ensure the cyber-resiliency of the supplier on an on-going basis.
The Sponsor has implemented (Corporate Policy 13.1 Information Security Standards 
Handbook) an organization-wide process to assign user access rights based on the whether 
the employee/contractor has a legitimate need to utilize a database in order to carry out 
his/her job; manager approval is required when granting user access rights (beyond those 
sites or databases intended for all employees/contractors); and a process is in place for an 
annual review by each manager of the user access rights currently in place.  Organizational 
measures, also contractually imposed on third party vendors, to prevent data processing 
systems from being used by unauthorized persons include i) user identification and 
authentication procedures (e.g., special characters, minimum length, regular change of 
password), and ii) automatic blocking (e.g., password or timeout).
The Sponsor utilizes a database called “InForm”, operated by Oracle, for the storage of its 
study subject clinical trial data. InForm is a role-based system and only authorized users can 
see the data. Sites may only see the data they have entered.  Access by Sponsor users is 
restricted to only those associated with a specific clinical trial. 
Study sites are provided with a password to access the database.  Access to InForm requires 
https (Secure Socket Layer) with a FIPS 140-2 compliant algorithm to connect to the 
application via the study site’s web browser.  Once logged into the system, the connection 
between the database, located in Ashburn, Virginia, USA, and the site, is encrypted.  The 
Sponsor also stores the name and access credentials of the Investigators and other site staff 
(Study Coordinators) who record patient data into InForm.  Such study staff personal data is 
not pseudonymized.  Note, such encryption during transmission may not meet all conditions 
imposed by the EDPB in its Recommendations for this encryption, on its own, to constitute 
an effective supplemental measure.
Data, whether concerning a study subject or site staff, stored in the InForm database is 
encrypted.  Note, such encryption may not meet all conditions imposed by the EDPB in its 
Recommendations for this encryption, on its own, to constitute an effective supplemental 
measure.  
Whenever possible, organization wide measures are imposed on third party vendors to 
prevent unauthorized persons from gaining access to the data processing systems available on 
premises and in facilities (including databases, application servers and related hardware), 
where Personal Data are processed, include i) Access control system (ID reader, chip), ii) key 
management, card-keys procedures, and iii) on-site security personnel and alarm system.
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InForm is a HIPAA Part 11 capable system.  Any data entered/changed or deleted will be 
associated with a viewable audit trail.
The Sponsor has EU-approved Binding Corporate Rules since 2017, covering all aspects of 
its Global Privacy Program (Corporate Policy 20).  Pursuant to organization-wide 
requirements, the Sponsor periodically conducts audits of the vendors providing IT services, 
including Oracle, the vendor supporting the InForm database.  The most recent audit of 
Oracle and its operations of InForm occurred in May 2020.  Finally, Oracle has obtained ISO 
27001 certification for the various databases it offers to third parties as a service, including 
the InForm database.   
10.1.3.1
Confidentiality of Data
By signing this protocol, the investigator affirms to the Sponsor that information furnished to 
the investigator by the Sponsor will be maintained in confidence, and such information will 
be divulged to the IRB, IEC, or similar or expert committee, affiliated institution, and 
employees, only under an appropriate understanding of confidentiality with such board or 
committee, affiliated institution, and employees. Data generated by this study will be 
considered confidential by the investigator, except to the extent that it is included in a 
publication as provided in the Publications section of this protocol.
10.1.3.2
Confidentiality of Participant Records
By signing this protocol, the investigator agrees that the Sponsor (or Sponsor representative), 
IRB/IEC, or regulatory authority representatives may consult and/or copy study documents to 
verify worksheet/CRF data. By signing the consent form, the participant agrees to this 
process. If study documents will be photocopied during the process of verifying 
worksheet/CRF information, the participant will be identified by unique code only; full 
names/initials will be masked before transmission to the Sponsor.
By signing this protocol, the investigator agrees to treat all participant data used and 
disclosed in connection with this study in accordance with all applicable privacy laws, rules, 
and regulations.
10.1.3.3
Confidentiality of IRB/IEC Information
The Sponsor is required to record the name and address of each IRB/IEC that reviews and 
approves this study. The Sponsor is also required to document that each IRB/IEC meets 
regulatory and ICH GCP requirements by requesting and maintaining records of the names 
and qualifications of the IRB/IEC members and to make these records available for 
regulatory agency review upon request by those agencies.
10.1.4
Committees Structure
10.1.4.1
Executive Oversight Committee
The EOC is comprised of members of Sponsor Senior Management. The EOC will receive 
and decide on any recommendations made by the eDMC regarding the study.
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10.1.4.2
External Data Monitoring Committee
To supplement the routine study monitoring outlined in this protocol, an external DMC will 
monitor the interim data from this study. The voting members of the committee are external 
to the Sponsor. The members of the DMC must not be involved with the study in any other 
way (eg, they cannot be study investigators) and must have no competing interests that could 
affect their roles with respect to the study.
The DMC will make recommendations to the EOC regarding steps to ensure both participant 
safety and the continued ethical integrity of the study. Also, the DMC will review interim 
study results, consider the overall risk and benefit to study participants (Section 9.6 ) and 
recommend to the EOC whether the study should continue in accordance with the protocol.
Specific details regarding composition, responsibilities, and governance, including the roles 
and responsibilities of the various members and the Sponsor protocol team ; meeting 
facilitation; the study governance structure; and requirements for and proper documentation 
of DMC reports, minutes, and recommendations will be described in the DMC charter that is 
reviewed and approved by all the DMC members.
10.1.5
Publication Policy
The results of this study may be published or presented at scientific meetings. 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.
If publication activity is not directed by the Sponsor, the investigator agrees to submit all 
manuscripts or abstracts to the Sponsor before submission. This allows the Sponsor to protect 
proprietary information and to provide comments.
Authorship will be determined by mutual agreement and in line with ICMJE authorship 
requirements.
10.1.6
Compliance with Study Registration and Results Posting Requirements
Under the terms of the FDAAA of 2007 and the EMA clinical trials Regulation 536/2014, the 
Sponsor of the study is solely responsible for determining whether the study and its results 
are subject to the requirements for submission to http://www.clinicaltrials.gov, 
www.clinicaltrialsregister.eu, https://euclinicaltrials.eu, or other local registries. MSD, as 
Sponsor of this study, will review this protocol and submit the information necessary to 
fulfill these requirements. MSD entries are not limited to FDAAA or the EMA clinical trials 
Regulation 536/2014 mandated trials. Information posted will allow participants to identify 
potentially appropriate studies for their disease conditions and pursue participation by calling 
a central contact number for further information on appropriate study locations and study-site 
contact information.
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By signing this protocol, the investigator acknowledges that the statutory obligations under 
FDAAA, the EMA clinical trials Regulation 536/2014, or other locally mandated registries 
are that of the Sponsor and agrees not to submit any information about this study or its results 
to those registries.
10.1.7
Compliance with Law, Audit, and Debarment
By signing this protocol, the investigator agrees to conduct the study in an efficient and 
diligent manner and in conformance with this protocol, generally accepted standards of GCP 
(eg, ICH GCP: Consolidated Guideline and other generally accepted standards of GCP), and 
all applicable federal, state, and local laws, rules, and regulations relating to the conduct of 
the clinical study.
The Code of Conduct, a collection of goals and considerations that govern the ethical and 
scientific conduct of clinical investigations sponsored by MSD, is provided in this appendix 
under the Code of Conduct for Clinical Trials.
The investigator agrees not to seek reimbursement from participants, their insurance 
providers, or from government programs for procedures included as part of the study 
reimbursed to the investigator by the Sponsor.
The investigator will promptly inform the Sponsor of any regulatory authority inspection 
conducted for this study.
The investigator agrees to provide the Sponsor with relevant information from inspection 
observations/findings to allow the Sponsor to assist in responding to any citations resulting 
from regulatory authority inspection and will provide the Sponsor with a copy of the 
proposed response for consultation before submission to the regulatory authority.
Persons debarred from conducting or working on clinical studies by any court or regulatory 
authority will not be allowed to conduct or work on this Sponsor’s studies. The investigator 
will immediately disclose in writing to the Sponsor if any person who is involved in 
conducting the study is debarred or if any proceeding for debarment is pending or, to the best 
of the investigator’s knowledge, threatened.
For investigators located in countries with serious breach reporting requirements, investigator 
will promptly report to the Sponsor any serious breach or suspected serious breach that 
occurs in compliance with those requirements. Unless more specifically defined in the 
applicable requirements, a serious breach is any breach of the applicable clinical trial 
regulation or of the clinical trial protocol which is likely to affect to a significant degree: (i) 
the safety or rights of a trial participant, or (ii) the reliability and robustness of the data 
generated in the clinical trial.
10.1.8
Data Quality Assurance
All participant data relating to the study will be recorded on printed or electronic CRF unless 
transmitted to the Sponsor or designee electronically (eg, laboratory data). The investigator 
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or qualified designee is responsible for verifying that data entries are accurate and correct by 
physically or electronically signing the CRF.
Detailed information regarding Data Management procedures for this protocol will be 
provided separately.
The investigator must maintain accurate documentation (source data) that supports the 
information entered in the CRF.
The investigator must permit study-related monitoring, audits, IRB/IEC review, and 
regulatory agency inspections and provide direct access to source data documents.
Study documentation will be promptly and fully disclosed to the Sponsor by the investigator 
upon request and also shall be made available at the study site upon request for inspection, 
copying, review, and audit at reasonable times by representatives of the Sponsor or any 
regulatory authorities. The investigator agrees to promptly take any reasonable steps that are 
requested by the Sponsor or any regulatory authorities as a result of an audit or inspection to 
cure deficiencies in the study documentation and worksheets/CRFs.
The Sponsor or designee is responsible for the data management of this study including 
quality checking of the data.
Study monitors will perform ongoing source data review and 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.
Records and documents, including participants’ documented informed consent, pertaining to 
the conduct of this study must be retained by the investigator for 15 years after study 
completion unless local regulations or institutional policies require a longer retention period. 
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.
10.1.9
Source Documents
Source documents provide evidence for the existence of the participant and substantiate the 
integrity of the data collected. The investigator/institution should maintain adequate and 
accurate source documents and study records that include all pertinent observations on each 
of the site’s participants. Source documents and data should be attributable, legible, 
contemporaneous, original, accurate, and complete. Changes to source data should be 
traceable, should not obscure the original entry, and should be explained if necessary (eg, via 
an audit trail). Source documents are filed at the investigator’s site.
Data reported on the CRF or entered in the eCRF that are transcribed from source documents 
must be consistent with the source documents or the discrepancies must be explained. The 
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investigator/institution may need to request previous medical records or transfer records, 
depending on the study. Also, current medical records must be available.
10.1.10
Study and Site Closure
The Sponsor or its designee may stop the study or study-site participation in the study for 
medical, safety, regulatory, administrative, or other reasons consistent with applicable laws, 
regulations, and GCP.
In the event the Sponsor prematurely terminates a particular study site, the Sponsor or 
designee will promptly notify that study site’s IRB/IEC as specified by applicable regulatory 
requirement(s).
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10.2
Appendix 2: Clinical Laboratory Tests
•
The tests detailed in Table 6 will be performed by the central laboratory.
•
Local laboratory results are only required in the event that the central laboratory results 
are not available in time for either study intervention administration and/or response 
evaluation. If a local sample is required at a scheduled visit, it is important that the 
sample for central analysis is obtained at the same time. Additionally, if the local 
laboratory results are used to make either a study intervention decision or response 
evaluation, the results must be entered into the CRF.
•
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.
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Table 6
Protocol-required Safety Laboratory Assessments
Laboratory 
Assessments
Parameters
Hematology
Platelet Count
RBC Indices:
MCV
MCH
% Reticulocytes
WBC count with 
Differential:
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
RBC Count
Hemoglobin
Hematocrit
Chemistry
BUN
Potassium
AST/SGOT
Total bilirubin (and direct 
bilirubin, if total bilirubin is 
above the ULN)
Albumin
Bicarbonate
Chloride
Phosphorous
Creatinine
Sodium
ALT/SGPT
Total Protein
Nonfasting 
glucose 
Calcium
Alkaline 
phosphatase
Routine Urinalysis
Specific gravity
pH, glucose, protein, blood, ketones
Microscopic examination (if blood or protein is abnormal)
Pregnancy Testing
Highly sensitive serum or urine hCG pregnancy test (as needed for POCBP)
Other Screening Tests
FSH (as needed in PONCBP only)
TSH
Serology (HIV antibody, HBsAg, HBcAb, HCV antibody)a. See Appendix 7 for 
country-specific requirements.
QuantiFERON- TB Gold test
PCR test (only required for participants exhibiting COVID-19 symptoms)
a Further testing will be needed for:
•
Participants with negative HBsAg and positive HBcAb must have further testing for HBV-DNA.
•
Participants with positive HCV Ab must have further testing for HCV-RNA.
Note: All Study-required laboratory assessments will be performed by a central laboratory, with the 
exception of urine pregnancy tests, COVID-19 PCR tests, and local TB tests, as applicable.
ALT=alanine aminotransferase; AST=aspartate aminotransferase; BUN=blood urea nitrogen; COVID-19=coronavirus 
disease 2019; FSH=follicle-stimulating hormone; HBsAg=hepatitis B surface antigen; hCG=human chorionic 
gonadotropin; HIV=human immunodeficiency virus; MCH=mean corpuscular hemoglobin; MCV=mean corpuscular 
volume; POCBP=persons of childbearing potential; RBC=red blood cell; SGOT=serum glutamic-oxaloacetic 
transaminase; SGPT=serum glutamic-pyruvic transaminase; ULN=upper limit of normal; WBC=white blood cells.
The investigator (or medically qualified designee) must document their review of each 
laboratory safety report.
See Appendix 7 for country-specific requirements.
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10.3
Appendix 3: Adverse Events: Definitions and Procedures for Recording, 
Evaluating, Follow-up, and Reporting
10.3.1
Definitions of Medication Error, Misuse, and Abuse
Medication error
This is an unintended failure in the drug treatment process that leads to or has the potential to 
lead to harm to the patient.
Misuse
This refers to situations where the medicinal product is intentionally and inappropriately used 
not in accordance with the terms of the product information.
Abuse
This corresponds to the persistent or sporadic intentional, excessive use of a medicinal 
product for a perceived psychological or physiological reward or desired nontherapeutic 
effect.
10.3.2
Definition of AE
AE definition
•
An AE is any untoward medical occurrence in a clinical study participant, temporally 
associated with the use of study intervention, whether or not considered related to the 
study intervention.
•
Note: An AE can therefore be any unfavorable and unintended sign (including an 
abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally 
associated with the use of a study intervention.
•
Note: For purposes of AE definition, study intervention includes any pharmaceutical 
product, biological product, vaccine, diagnostic agent, medical device, combination 
product, or protocol-specified procedure whether investigational or marketed (including 
placebo, active comparator product, or run-in intervention), manufactured by, licensed 
by, provided by, or distributed by the Sponsor for human use in this study.
Events meeting the AE definition
•
Any abnormal laboratory test results (hematology, clinical chemistry, or urinalysis) or 
other safety assessments (eg, ECG, radiological scans, vital signs measurements), 
including those that worsen from baseline, considered clinically significant in the medical 
and scientific judgment of the investigator.
•
Exacerbation of a chronic or intermittent preexisting condition including either an 
increase in frequency and/or intensity of the condition.
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•
New conditions detected or diagnosed after study intervention administration even 
though it may have been present before the start of the study.
•
Signs, symptoms, or the clinical sequelae of a suspected drug-drug interaction.
•
Signs, symptoms, or the clinical sequelae of a suspected overdose of either study 
intervention or a concomitant medication.
•
For all reports of overdose (whether accidental or intentional) with an associated AE, the 
AE term should reflect the clinical symptoms or abnormal test result. An overdose 
without any associated clinical symptoms or abnormal laboratory results is reported using 
the terminology “accidental or intentional overdose without adverse effect.”
•
Any new cancer or progression of existing cancer. 
Events NOT meeting the AE definition
•
Medical or surgical procedure (eg, endoscopy, appendectomy): the condition that leads to 
the procedure is the AE.
•
Situations in which an untoward medical occurrence did not occur (social and/or 
convenience admission to a hospital).
•
Anticipated day-to-day fluctuations of preexisting disease(s) or condition(s) present or 
detected at the start of the study that do not worsen.
•
Surgical procedure(s) planned prior to informed consent to treat a preexisting condition 
that has not worsened.
•
Refer to Section 8.4.6 for protocol-specific exceptions.
10.3.3
Definition of SAE
If an event is not an AE per definition above, then it cannot be an SAE even if serious 
conditions are met.
An SAE is defined as any untoward medical occurrence that, at any dose:
a.
Results in death
b. Is life-threatening
-
The term “life-threatening” in the definition of “serious” refers to an event in which 
the participant was at risk of death at the time of the event. It does not refer to an 
event, which hypothetically might have caused death, if it were more severe.
c.
Requires inpatient hospitalization or prolongation of existing hospitalization
-
Hospitalization is defined as an inpatient admission, regardless of length of stay, even 
if the hospitalization is a precautionary measure for continued observation. (Note: 
Hospitalization for an elective procedure to treat a preexisting condition that has not 
worsened is not an SAE.) A preexisting condition is a clinical condition that is 
diagnosed prior to the use of an MSD product and is documented in the participant’s 
medical history.
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d. Results in persistent or significant disability/incapacity
-
The term disability means a substantial disruption of a person’s ability to conduct 
normal life functions.
-
This definition is not intended to include experiences of relatively minor medical 
significance such as uncomplicated headache, nausea, vomiting, diarrhea, influenza, 
and accidental trauma (eg, sprained ankle) that may interfere with or prevent 
everyday life functions but do not constitute a substantial disruption.
e.
Is a congenital anomaly/birth defect
-
In offspring of participant taking the product regardless of time to diagnosis.
f.
Other important medical events
-
Medical or scientific judgment should be exercised in deciding whether SAE 
reporting is appropriate in other situations such as important medical events that may 
not be immediately life-threatening or result in death or hospitalization but may 
jeopardize the participant or may require medical or surgical intervention to prevent 1 
of the other outcomes listed in the above definition. These events should usually be 
considered serious.
-
Examples of such events include invasive or malignant cancers, intensive treatment in 
an emergency room or at home for allergic bronchospasm, blood dyscrasias, or 
convulsions that do not result in hospitalization, or development of drug dependency 
or drug abuse.
10.3.4
Additional Events Reported
Additional events that require reporting
In addition to the above criteria, AEs meeting either of the below criteria, although not 
serious per ICH definition, are reportable to the Sponsor.
•
Is a cancer.
•
Is associated with an overdose.
10.3.5
Recording AE and SAE
AE and SAE recording
•
When an AE/SAE occurs, it is the responsibility of the investigator to review all 
documentation (eg, hospital progress notes, laboratory, and diagnostics reports) related to 
the event.
•
The investigator will record all relevant AE/SAE information on the AE 
CRFs/worksheets at each examination.
•
It is not acceptable for the investigator to send photocopies of the participant’s medical 
records to the Sponsor in lieu of completion of the AE CRF page.
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•
There may be instances when copies of medical records for certain cases are requested by 
the Sponsor. In this case, all participant identifiers, with the exception of the participant 
number, will be blinded on the copies of the medical records before submission to the 
Sponsor.
•
The investigator will attempt to establish a diagnosis of the event based on signs, 
symptoms, and/or other clinical information. In such cases, the diagnosis (not the 
individual signs/symptoms) will be documented as the AE/SAE.
Assessment of intensity
•
An event is defined as “serious” when it meets at least 1 of the predefined outcomes as 
described in the definition of an SAE, not when it is rated as severe.
•
The investigator will make an assessment of intensity for each AE and SAE (and other 
reportable safety event) reported during the study and assign it to 1 of the following 
categories:
-
Mild: An event that is easily tolerated by the participant, causing minimal discomfort, 
and not interfering with everyday activities (for pediatric studies, awareness of 
symptoms, but easily tolerated).
-
Moderate: An event that causes sufficient discomfort to interfere with normal 
everyday activities (for pediatric studies, definitely acting like something is wrong).
-
Severe: An event that prevents normal everyday activities. An AE that is assessed as 
severe should not be confused with an SAE. Severe is a category used for rating the 
intensity of an event; and both AE and SAE can be assessed as severe (for pediatric 
studies, extremely distressed or unable to do usual activities).
Assessment of causality
•
Did the study intervention cause the AE?
•
The determination of the likelihood that the study intervention caused the AE will be 
provided by an investigator who is a qualified physician. The investigator’s signed/dated 
initials on the source document or worksheet that supports the causality noted on the AE 
form, ensures that a medically qualified assessment of causality was done. This initialed 
document must be retained for the required regulatory time frame. The criteria below are 
intended as reference guidelines to assist the investigator in assessing the likelihood of a 
relationship between the test product and the AE based upon the available information.
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•
The following components are to be used to assess the relationship between the 
study intervention and the AE; the greater the correlation with the components and 
their respective elements (in number and/or intensity), the more likely the study 
intervention caused the AE:
-
Exposure: Is there evidence that the participant was actually exposed to the study 
intervention such as: reliable history, acceptable compliance assessment (pill count, 
diary, etc), expected pharmacologic effect, or measurement of drug/metabolite in 
bodily specimen?
-
Time Course: Did the AE follow in a reasonable temporal sequence from 
administration of the study intervention? Is the time of onset of the AE compatible 
with a drug-induced effect (applies to studies with investigational medicinal product)?
-
Likely Cause: Is the AE not reasonably explained by another etiology such as 
underlying disease, other drug(s)/vaccine(s), or other host or environmental factors.
-
Dechallenge: Was the study intervention discontinued or dose/exposure/frequency 
reduced?

If yes, did the AE resolve or improve?

If yes, this is a positive dechallenge.

If no, this is a negative dechallenge.
(Note: This criterion is not applicable if: (1) the AE resulted in death or permanent 
disability; (2) the AE resolved/improved despite continuation of the study 
intervention; (3) the study is a single-dose drug study; or (4) study intervention (s) 
is/are only used 1 time.)
-
Rechallenge: Was the participant reexposed to the study intervention in this study?

If yes, did the AE recur or worsen?

If yes, this is a positive rechallenge.

If no, this is a negative rechallenge.
(Note: This criterion is not applicable if: (1) the initial AE resulted in death or 
permanent disability; (2) the study is a single-dose drug study; or (3) study 
intervention (s) is/are used only 1 time.)
NOTE: IF A RECHALLENGE IS PLANNED FOR AN AE THAT WAS SERIOUS AND 
MAY HAVE BEEN CAUSED BY THE STUDY INTERVENTION, OR IF REEXPOSURE 
TO THE STUDY INTERVENTION POSES ADDITIONAL POTENTIAL SIGNIFICANT 
RISK TO THE PARTICIPANT THEN THE RECHALLENGE MUST BE APPROVED IN 
ADVANCE BY THE SPONSOR CLINICAL DIRECTOR, AND IF REQUIRED, THE 
IRB/IEC.
•
Consistency with study intervention profile: Is the clinical/pathological presentation of 
the AE consistent with previous knowledge regarding the study intervention or drug class 
pharmacology or toxicology?
•
The assessment of relationship will be reported on the CRFs/worksheets by an 
investigator who is a qualified physician according to their best clinical judgment, 
including consideration of the above elements.
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•
Use the following scale of criteria as guidance (not all criteria must be present to be 
indicative of a study intervention relationship).
-
Yes, there is a reasonable possibility of study intervention relationship:

There is evidence of exposure to the study intervention. The temporal sequence of 
the AE onset relative to the administration of the study intervention is reasonable. 
The AE is more likely explained by the study intervention than by another cause.
-
No, there is not a reasonable possibility of study intervention relationship:

Participant did not receive the study intervention OR temporal sequence of the AE 
onset relative to administration of the study intervention is not reasonable OR the 
AE is more likely explained by another cause than the study intervention. (Also 
entered for a participant with overdose without an associated AE.)
•
The investigator must review and provide an assessment of causality for each AE/SAE
and document this in the medical notes.
•
There may be situations in which an SAE has occurred and the investigator has minimal 
information to include in the initial report to the Sponsor. However, it is very important 
that the investigator always make an assessment of causality for every event before the 
initial transmission of the SAE data to the Sponsor.
•
The investigator may change their opinion of causality in light of follow-up information 
and send an SAE follow-up report with the updated causality assessment.
•
The causality assessment is 1 of the criteria used when determining regulatory reporting 
requirements.
Follow-up of AE and SAE
•
The investigator is obligated to perform or arrange for the conduct of supplemental 
measurements and/or evaluations as medically indicated or as requested by Sponsor to 
elucidate the nature and/or causality of the AE or SAE as fully as possible. This may 
include additional laboratory tests or investigations, histopathological examinations, or 
consultation with other health care professionals.
•
New or updated information will be recorded in the CRF.
•
The investigator will submit any updated SAE data to the Sponsor within 24 hours of 
receipt of the information.
10.3.6
Reporting of AEs, SAEs, and Other Reportable Safety Events to the Sponsor
AE, SAE, and other reportable safety event reporting to Sponsor via electronic data 
collection tool
•
The primary mechanism for reporting to the Sponsor will be the EDC tool.
o
Electronic reporting procedures can be found in the EDC data entry guidelines (or 
equivalent).
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o
If the electronic system is unavailable for more than 24 hours, then the site will use 
the paper AE Reporting form.
o
Reference Section 8.4.1 for reporting time requirements.
•
The site will enter the SAE data into the electronic system as soon as it becomes 
available.
•
After the study is completed at a given site, the EDC tool will be taken off-line to prevent 
the entry of new data or changes to existing data.
•
If a site receives a report of a new SAE from a study participant or receives updated data 
on a previously reported SAE after the EDC tool has been taken off-line, then the site can 
report this information on a paper SAE form or by telephone (see next section).
•
Contacts for SAE reporting can be found in the Investigator Study File Binder (or 
equivalent).
SAE reporting to the Sponsor via paper CRF
•
If the EDC tool is not operational, facsimile transmission or secure email of the SAE 
paper CRF is the preferred method to transmit this information to the Sponsor.
•
In rare circumstances and in the absence of facsimile equipment, notification by 
telephone is acceptable with a copy of the SAE data collection tool sent by overnight 
mail or courier service.
•
Initial notification via telephone does not replace the need for the investigator to 
complete and sign the SAE CRF pages within the designated reporting time frames.
•
Contacts and instructions for SAE reporting and paper reporting procedures can be found 
in the Investigator Study File Binder (or equivalent).
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10.4
Appendix 4: Drug-Device Combination Products/ Combination Medicinal 
Products: Complaints, Product Quality Complaints/Malfunctions: Definitions, 
Recording, and Follow-up
The recording and follow-up procedures described in this protocol apply to drug-device 
combination products/combination medicinal products. For purposes of this section, medical 
devices in scope for device information collection include drug-device combination 
products/combination medicinal products listed in Section 6.1.1. Product Quality 
Complaints/Malfunctions must be reported to the Sponsor.
10.4.1
Definitions
Combination Product – A product composed of any combination of a drug, a device, and a 
biological product. Each drug, device, and biological product included in a combination 
product is referred to as a “constituent part” of the combination product.
Complaint – Any written, electronic, or oral communication that alleges deficiencies related 
to the identity, quality, durability, reliability, safety, effectiveness, or performance of a device 
after it is released for distribution. 
A complaint does not necessarily need to involve a user or any other person.
Constituent Part – A drug, device, or biological product that is part of a combination 
product.
Malfunction – The failure of a device including the device component of a combination 
product to meet its performance specifications or otherwise perform as intended. 
Performance specifications include all claims made in the labeling for the medical 
device/device constituent part. The intended performance of a device refers to the intended 
use for which the device is labeled or marketed.
Medical Device – Any instrument, apparatus, appliance, implement, machine, contrivance, 
implant, in-vitro reagent or other similar or related article, including a component part, or 
accessory which is intended for use in the diagnosis of disease or other conditions, or in the 
cure, mitigation, treatment, or prevention of disease, in man or other animals, or intended to 
affect the structure or any function of the body of man or other animals and which does not 
achieve its primary intended purposes through chemical action within or on the body of man 
or other animals and which is not dependent upon being metabolized for the achievement of 
any of its primary intended purposes.
PQC – Any communication (written or oral) that describes a potential defect related to the 
identity, strength, quality, purity, or performance of a product identified by external 
customers. This includes potential device or device component malfunctions.
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Serious Deterioration of Health/Serious Injury/Serious Illness – This includes:
1.    Life-threatening illness, even if temporary in nature,
2.    Results in permanent impairment of a body function or permanent damage to a body 
structure, or
3.    A condition necessitating medical or surgical intervention, including hospitalization or 
prolonged hospitalization to preclude permanent impairment of a body function or 
permanent damage to a body structure.
4.    Cases that are considered medically significant,
5.    Fetal distress, fetal death, or any congenital abnormality or birth defects.
Permanent means irreversible impairment or damage to a body structure or function, 
excluding trivial impairment or damage.
Japan specific definitions and documenting/reporting requirements can be found in 
Section 10.7.
10.4.2
Recording, Assessing Causality, and Follow-up of PQCs/Malfunctions
Recording
When a complaint, including PQC/malfunction occurs it is the responsibility of the 
investigator to review all documentation (eg, hospital progress notes, laboratory reports, and 
diagnostic reports) related to the event.
Adverse Events occurring during the study will be recorded in the participant’s medical 
records (or equivalent), in accordance with the investigator’s normal clinical practice, and on 
the appropriate CRF (paper or electronic) as per instructions provided in the data entry 
guidelines (or equivalent). Device constituent part of drug-device combination 
product/combination medicinal product information (regardless of participant or associated 
person) will be collected and reported to the Sponsor in the same time frame as SAEs as per 
Section 8.4.1 via CRF (paper or electronic). PQCs/malfunctions must be reported to the 
Sponsor. It is important that the investigator provides an assessment of causality (relationship 
to the medical device) at the time of the initial report.
Assessing Causality
A “reasonable possibility” of a relationship conveys that there are facts, evidence, and/or 
arguments to suggest a causal relationship.
The investigator will use clinical judgment to determine the relationship.
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Alternative causes such as underlying disease(s), concomitant therapy, and other risk factors, 
as well as the temporal relationship of the event to study intervention administration should 
be considered and investigated.
Follow-up
The investigator will perform or arrange for the conduct of supplemental measurements 
and/or evaluations as medically indicated or as requested by the Sponsor to elucidate the 
nature and/or causality of the event as complete as possible.
See Appendix 7 for country-specific requirements.
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10.5
Appendix 5: Contraceptive Guidance
10.5.1
Definitions
Participants of Childbearing Potential (POCBP)
A participant assigned female sex at birth is considered fertile following menarche and 
capable of becoming pregnant until becoming postmenopausal unless permanently sterile 
(see below):
If fertility is unclear (eg, amenorrhea in adolescents or athletes) and a menstrual cycle cannot 
be confirmed before first dose of study intervention, additional evaluation should be 
considered.
Participants assigned female sex at birth who are in the following categories are not capable 
of becoming pregnant and, therefore, not considered POCBP:
•
Premenarchal
•
Premenopausal with 1 of the following:
-
Documented hysterectomy
-
Documented bilateral salpingectomy
-
Documented bilateral oophorectomy
For individuals with permanent infertility due to an alternate medical cause other than the 
above (eg, Müllerian agenesis, androgen insensitivity), investigator discretion should be 
applied to determining study entry.
Note: Documentation can come from the site personnel’s review of the participant’s 
medical records, medical examination, or medical history interview.
•
Postmenopausal
-
A postmenopausal state is defined as no menses for 12 months without an alternative 
medical cause.

A high FSH level in the postmenopausal range may be used to confirm a 
postmenopausal state in participants assigned female sex at birth who are not 
using hormonal contraception or HRT. However, in the absence of 12 months of 
amenorrhea, confirmation with 2 FSH measurements in the postmenopausal range 
is required.
-
Participants assigned female sex at birth who are on HRT and whose menopausal 
status is in doubt will be required to use one of the nonhormonal highly effective 
contraception methods if they wish to continue their HRT during the study. 
Otherwise, they must discontinue HRT to allow confirmation of postmenopausal 
status before study enrollment.
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10.5.2
Contraceptive Requirements
Contraceptives allowed during the study include:
Highly Effective Contraceptive Methods That Have Low User Dependencya
Failure rate of <1% per year when used consistently and correctly.
Progestogen-only subdermal contraceptive implantb,c
IUSb,d
Nonhormonal IUD
Bilateral tubal occlusion
Azoospermic partner (vasectomized or secondary to medical cause) –
All sexual partner(s) of the POCBP must be azoospermic. The participant must provide verbal 
confirmation of partner azoospermia during Medical History. If not, an additional highly effective method 
of contraception should be used. A spermatogenesis cycle is approximately 90 days.
Highly Effective Contraceptive Methods That Are User Dependentb
Failure rate of <1% per year when used consistently and correctly.
Combined (estrogen- and progestogen-containing) hormonal contraception b,c
- Oral
- Intravaginal
- Transdermal
- Injectable
Progestogen-only hormonal contraception b,c
- Oral
- Injectable
Sexual Abstinence
Sexual abstinence is considered a highly effective method only if defined as refraining from penile-
vaginal intercourse with a partner capable of producing sperm, 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.
a
Typical use failure rates are higher than perfect-use failure rates (ie, when used consistently and correctly).
b
Penile/external condoms must be used in addition to the POCBP’s hormonal contraception.
c
If locally required, in accordance with CTFG guidelines, acceptable contraceptives are limited to those which inhibit 
ovulation.
d
IUS is a progestin-releasing IUD.
Note:
Tubal occlusion includes tubal ligation
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10.6
Appendix 6: Collection and Management of Specimens for Future Biomedical 
Research
1. Definitions
a.
Biomarker: A biological molecule found in blood, other body fluids, or tissues that is 
a sign of a normal or abnormal process or of a condition or disease. A biomarker may 
be used to see how well the body responds to a treatment for a disease or condition.1
b. Pharmacogenomics: The investigation of variations of DNA and RNA characteristics 
as related to drug/vaccine response.2
c.
Pharmacogenetics: A subset of pharmacogenomics, pharmacogenetics is the influence 
of variations in DNA sequence on drug/vaccine response.2
d. DNA: Deoxyribonucleic acid.
e.
RNA: Ribonucleic acid.
2. Scope of Future Biomedical Research3, 4
The specimens consented and/or collected in this study as outlined in Section 8.9 will be 
used in various experiments to understand:
-
The biology of how drugs/vaccines work
-
Biomarkers responsible for how a drug/vaccine enters and is removed by the body
-
Other pathways with which drugs/vaccines may interact
-
The biology of disease
The specimen(s) may be used for future assay development and/or drug/vaccine 
development.
It is now well recognized that information obtained from studying and testing clinical 
specimens offers unique opportunities to enhance our understanding of how individuals 
respond to drugs/vaccines, enhance our understanding of human disease, and ultimately 
improve public health through development of novel treatments targeted to populations 
with the greatest need. All specimens will be used by the Sponsor or those working for or 
with the Sponsor.
3. Summary of Procedures for Future Biomedical Research3, 4
a.
Participants for Enrollment
All participants enrolled in the clinical study will be considered for enrollment in 
future biomedical research.
b. Informed Consent
Informed consent for specimens (ie, DNA, RNA, protein, etc) will be obtained during 
screening for protocol enrollment from all participants or legal guardians, at a study 
visit by the investigator or his or her designate. Informed consent for future 
biomedical research should be presented to the participants on the visit designated in 
the SoA. If delayed, present consent at next possible Participant Visit. Consent forms 
signed by the participant will be kept at the clinical study site under secure storage for 
regulatory reasons.
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A template of each study site’s approved informed consent will be stored in the 
Sponsor’s clinical document repository.
c.
eCRF Documentation for Future Biomedical Research Specimens
Documentation of participant consent for future biomedical research will be captured 
in the eCRFs. Any specimens for which such an informed consent cannot be verified 
will be destroyed.
d. Future Biomedical Research Specimen(s)
Collection of specimens for future biomedical research will be performed as outlined 
in the SoA. In general, if additional blood specimens are being collected for future 
biomedical research, these will usually be obtained at a time when the participant is 
having blood drawn for other study purposes.
4. Confidential Participant Information for Future Biomedical Research3, 4
In order to optimize the research that can be conducted with future biomedical research 
specimens, it is critical to link participants’ clinical information with future test results. In 
fact, little or no research can be conducted without connecting the clinical study data to 
the specimen. The clinical data allow specific analyses to be conducted. Knowing 
participant characteristics like sex, age, medical history, and intervention outcomes is
critical to understanding clinical context of analytical results.
To maintain privacy of information collected from specimens obtained for future 
biomedical research, the Sponsor has developed secure policies and procedures. All 
specimens will be single coded per ICH E15 guidelines as described below.
At the clinical study site, unique codes will be placed on the future biomedical research 
specimens. This code is a random number that does not contain any personally 
identifying information embedded within it. The link (or key) between participant 
identifiers and this unique code will be held at the study site. No personal identifiers will 
appear on the specimen tube.
5. Biorepository Specimen Usage3, 4
Specimens obtained for the Sponsor will be used for analyses using good scientific 
practices. Analyses using the future biomedical research specimens may be performed by 
the Sponsor, or an additional third party (eg, a university investigator) designated by the 
Sponsor. The investigator conducting the analysis will follow the Sponsor’s privacy and 
confidentiality requirements. Any contracted third-party analyses will conform to the 
specific scope of analysis outlined in future biomedical research protocol and consent. 
Future biomedical research specimens remaining with the third party after specific 
analysis is performed will be reported to the Sponsor.
6. Withdrawal From Future Biomedical Research3, 4
Participants may withdraw their consent for FBR and ask that their biospecimens not be 
used for FBR. Participants may withdraw consent at any time by contacting the study 
investigator. If medical records for the study are still available, the investigator will 
contact the Sponsor using the designated mailbox 
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(clinical.specimen.management@MSD.com). Subsequently, the participant's specimens 
will be flagged in the biorepository and restricted to study use only. If specimens were 
collected from study participants specifically for FBR, these specimens will be removed 
from the biorepository and destroyed. Documentation will be sent to the investigator 
confirming withdrawal and/or destruction, if applicable. It is the responsibility of the 
investigator to inform the participant of completion of the withdrawal and/or destruction, 
if applicable. Any analyses in progress at the time of request for withdrawal/destruction 
or already performed before the request being received by the Sponsor will continue to be 
used as part of the overall research study data and results. No new analyses would be 
generated after the request is received.
If the medical records for the study are no longer available (eg, if the investigator is no 
longer required by regulatory authorities to retain the study records) or the specimens 
have been completely anonymized, there will no longer be a link between the 
participant’s personal information and their specimens. In this situation, the request for 
withdrawal of consent and/or destruction cannot be processed.
7. Retention of Specimens3, 4
Future biomedical research specimens will be stored in the biorepository for potential 
analysis for up to 20 years from the end of the study. Specimens may be stored for longer 
if a regulatory or governmental authority has active questions that are being answered. In 
this special circumstance, specimens will be stored until these questions have been 
adequately addressed.
Specimens from the study site will be shipped to a central laboratory and then shipped to 
the Sponsor-designated biorepository. If a central laboratory is not used in a particular 
study, the study site will ship directly to the Sponsor-designated biorepository. The 
specimens will be stored under strict supervision in a limited access facility, which 
operates to assure the integrity of the specimens. Specimens will be destroyed according 
to Sponsor policies and procedures and this destruction will be documented in the 
biorepository database.
8. Data Security3, 4
Databases containing specimen information and test results are accessible only to the 
authorized Sponsor representatives and the designated study administrator research 
personnel and/or collaborators. Database user authentication is highly secure, and is 
accomplished using network security policies and practices based on international 
standards to protect against unauthorized access.
9. Reporting of Future Biomedical Research Data to Participants3, 4
No information obtained from exploratory laboratory studies will be reported to the 
participant, family, or physicians. Principle reasons not to inform or return results to the 
participant include lack of relevance to participant health, limitations of predictive 
capability, and concerns regarding misinterpretation.
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If important research findings are discovered, the Sponsor may publish results, present 
results in national meetings, and make results accessible on a public website in order to 
rapidly report this information to doctors and participants. Participants will not be 
identified by name in any published reports about this study or in any other scientific 
publication or presentation.
10. Future Biomedical Research Study Population3, 4
Every effort will be made to recruit all participants diagnosed and treated on Sponsor 
clinical studies for future biomedical research.
11. Risks Versus Benefits of Future Biomedical Research3, 4
For future biomedical research, risks to the participant have been minimized and are 
described in the future biomedical research informed consent.
The Sponsor has developed strict security, policies, and procedures to address participant 
data privacy concerns. Data privacy risks are largely limited to rare situations involving 
possible breach of confidentiality. In this highly unlikely situation, there is risk that the 
information, like all medical information, may be misused.
12. Questions
Any questions related to the future biomedical research should be emailed directly to 
clinical.specimen.management@MSD.com.
13. References
1. National Cancer Institute [Internet]: Available from 
https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=45618
2. International Council on Harmonisation [Internet]: E15: Definitions for Genomic 
Biomarkers, Pharmacogenomics, Pharmacogenetics, Genomic Data and Sample 
Coding Categories. Available from 
http://www.ich.org/products/guidelines/efficacy/efficacy-single/article/definitions-
for-genomic-biomarkers-pharmacogenomics-pharmacogenetics-genomic-data-and-
sample-cod.html
3. Industry Pharmacogenomics Working Group [Internet]: Understanding the Intent, 
Scope and Public Health Benefits of Exploratory Biomarker Research: A Guide for 
IRBs/IECs and Investigational Site Staff. Available at http://i-pwg.org/
4. Industry Pharmacogenomics Working Group [Internet]: Pharmacogenomics 
Informational Brochure for IRBs/IECs and Investigational Site Staff. Available at 
http://i-pwg.org/
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10.7
Appendix 7: Country-specific Requirements
10.7.1
Country specific Requirements for Argentina
Section 1.3 Schedule of Activities
HBV, HCV, TB, and HIV testing at Screening is mandatory.
Section 1.3 Schedule of Activities and Section 8.3.5 Pregnancy Testing
Pregnancy testing must be performed monthly during treatment as well as at the end of study 
intervention.
10.7.2
Country specific Requirements for the Czech Republic
Section 6.5 Concomitant Therapy
In addition to all restrictions or concomitant medications listed in Section 6.5, specific 
concomitant therapies or vaccinations noted below are prohibited during the study:
•
Live vaccines must not be administered within 30 days prior to the first dose of study 
intervention, while participating in the study, and for 90 days after the last dose of study 
intervention.
Section 8.3.5 Pregnancy Testing
Pregnancy testing is to be conducted every 30 days during the treatment period.
10.7.3
Country-specific Requirements for Germany
Sections 1.1, 4.4, 5.1, 7.1, 7.2, 8.1.1, 8.1.1.1, 8.1.1.2, 8.1.1.3
For a participant to be eligible to participate in Germany, they must be capable of providing 
documented informed consent; therefore, all references to a participant’s “legally acceptable 
representative” in the protocol are not applicable for participants in Germany.
Section 8.3.7 Chest X-ray
Chest x-rays and/or CT scans will not be implemented in Germany. Participants will be 
screened for TB using the QFT Test or equivalent as outlined in Section 8.3.7.
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10.7.4
Country-specific Requirements for Japan
Section 1.3.1 Double-Blind Treatment Period
Study Period:
Screen
Double-Blind Treatment Period
Notes
Visit Number/Title:
1 Screen
2
Rand
3
4
5
TC
6
7
8
9
TC
10a
Discon
Scheduled Day/Week
Up to 4 
wks
Day 1
Wk 0
Day 2
Wk 
2
Wk 
4
Wk 
6
Wk 
8
Wk 
12
Wk12 
+1d
Wk 
18
Wk 
20
Wk 
24
Day
1
2
15
29
43
57
85
86
141
169
Recommended Window
±12h
±3d
±3d
±3d
±7d
±7d
±12h
±7d
±3d
±7d
Safety Procedures
HBV-DNA testing
X
X
X
X
Only for participants 
with positive 
HBcAb and/or 
positive HBsAb 
and HBV-DNA 
<LLOQ at 
Screening
Section 1.3.2 Blinded Extension Period
Study Period:
Blinded Extension Period
Notes
Visit Number/Title:
10a
11
12
13
14
15
TC
16
Disco
n
F/U
TC
Scheduled Day/Week
Wk 24
Wk 
26
Wk 
28
Wk 
32
Wk 
36
Wk 
44
Wk 
48
Wk
52
28 Days 
after Last 
Dose
Day
169
183
197
225
253
309
337
365
Recommended Window:
±7d
±3d
±3d
±7d
±7d
±7d
±3d
±7d
+7d
Safety Procedures
HBV-DNA testing
X
X
X
X
Only for participants with 
positive HBcAb and/or 
positive HBsAb and HBV-
DNA <LLOQ at Screening
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Section 10.2
HBV Testing
Table Protocol-required Safety Laboratory Assessments
Other Screening Tests
HBsAb
HBsAb= hepatitis B surface antibody
Section 5.2: Exclusion Criteria and Section 8.3.8 HBV, HCV, and HIV Testing
12. Is known to be infected with HBV, HCV, or HIV:
•
Participants with positive HBsAg are excluded from the study.
•
For participants with positive HBsAb and negative HBcAb, HBV-DNA testing at 
screening is required. If HBV-DNA is ≥LLOQ, the participant must be excluded. If 
HBV-DNA is <LLOQ, participant may be enrolled and HBV-DNA testing should be 
performed approximately every 12 weeks (in correlation with a scheduled visit) and at 
last scheduled visit. If subsequently, HBV-DNA is ≥LLOQ, the participant will require 
discontinuation of study intervention (Section 7.1).
•
For participants with positive HBcAb and/or positive HBsAb and HBV-DNA is <LLOQ
at Screening, HBV-DNA testing should be performed approximately every 12 weeks (in 
correlation with a scheduled visit) and at last scheduled visit. If HBV-DNA is ≥LLOQ, 
the participant will require discontinuation of study intervention (Section 7.1).
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HBV, HCV, HIV Testing
DNA=deoxyribonucleic acid, HBcAb=hepatitis B core antibody, HBsAg=hepatitis B surface antigen, HBV=hepatitis B 
virus, LLOQ=lower limit of quantification.
a. For participants with positive HBsAb and negative HBcAb who have had a HBV vaccination, HBV-DNA testing is 
required at Screening. However, HBV-DNA monitoring after randomization is not required. The vaccination history must be 
documented in the medical records. 
b These participants should have HBV-DNA testing performed approximately every 12 weeks (in correlation with a 
scheduled visit). If HBV-DNA is ≥LLOQ, the participant will require discontinuation of study intervention (Section 7.1).
Sections 4.1, 8.1.9, 8.1.9.3, 8.1.9.4
In Japan, administration of study intervention is not be permitted by a caregiver.
10.4 Appendix 4: Drug-Device Combination Products/ Combination Medicinal Products: 
Complaints, Product Quality Complaints/Malfunctions: Definitions, Recording, and 
Follow-up
Section 10.4.1 Definitions
Medical Device - Devices, etc. (other than regenerative medicine products) intended for use 
in the diagnosis, treatment, or prevention of disease in humans or animals, or intended to 
affect the structure or functions of humans or animals.
Combination Medicinal Product - The products to be manufactured and marketed as a single 
drug, medical device, or regenerative medical product by combining 2 or more different type 
of drugs, medical devices or processed cells that are presumed to fall under the category of 
drugs, medical devices, or regenerative medical products if it is distributed alone.
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Malfunction - When the device constituent part of a combination medicinal product, as 
described in the protocol, has quality, safety, or performance issue, such as damage or failure 
in operation, regardless of the stage of design, delivery, storage, or use.
Serious Adverse Event due to Malfunction - A SAE occurring in a participant (and/or the 
associated person) in a clinical trial caused by, or suspected to be caused by, the use of the 
device constituent part of the combination medicinal product, as described in the protocol.
Malfunction That may Lead to Serious Adverse Events - Any malfunction of a device 
constituent part of a combination medicinal product, as described in the protocol, which 
might have led to the death of a participant (and/or the associated person), or to a serious 
deterioration in their state of health. “Which might have led to” means there is the possibility 
death, or a serious deterioration might have occurred in a participant (and/or the associated 
person), although no event has occurred.
Section 10.4.2 Recording, Assessing Causality, and Follow-up of Complaints, 
PQCs/Malfunctions
Malfunction which may lead to SAEs will be reported to the Sponsor within 5 calendar days 
of learning of the information via a paper reporting form.
10.7.5
Country-Specific Requirements for France
Section 5.2: Exclusion Criteria
In addition to all exclusion criteria listed in Section 5.2, the General principles relating to 
research involving human beings (Art. L. 1121-6, Art. L. 1121-8, Art. L. 1121-8-1) are to be 
followed. 
Adults protected by laws, persons deprived of their liberty by a judicial or administrative 
decision, those hospitalized without consent in accordance with local law as further defined 
in the informed consent form, persons admitted to a health or social institution for purposes 
other than research and adults who are subject to a legal protection measure or who are 
unable to express their consent are not eligible to participate.
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10.8
Appendix 8: Examples of Commonly Used Medications/Vaccines
Biologic Therapies
Immune Checkpoint Inhibitors
Immune checkpoint inhibitors are not allowed at any time prior to Randomization and 
throughout the study until the last dose of study intervention. Examples of immune 
checkpoint inhibitors include, but are not limited to, the medications in Table 7.
Table 7
Commonly Used Immune Checkpoint Inhibitors
PD-1 Inhibitors
PD-L1 Inhibitors
CTLA-4 Inhibitors
Cemiplimab
Nivolumab
Pembrolizumab
Atezolizumab
Avelumab
Durvalumab
Ipilimumab
Tremelimumab
Biologic Therapies With Immunosuppressive Potential
Biologic therapies with immunosuppressive potential are prohibited within 3 months or 5 
half-lives (whichever is longer) prior to Randomization and throughout the study until the 
last dose of study intervention with the exception of T and B cell depleting therapies(Table 
1). Examples of prohibited biologics include, but are not limited to, the medications in Table 
8.
Table 8
Commonly Used Biologic Therapies
Name of Medication
Abatacept
Adalimumab
Anakinra
Anifrolumab-fnia
Belimumab
Certolizumab
Dupilumab
Etanercept
Guselkumab 
Golimumab
Infliximab
Ixekizumab
Lebrikizumab
Mepolizumab
Natalizumab
Nemolizumab
Reslizumab
Risankizumab
Secukinumab
Tocilizumab
Tralokinumab
Ustekinumab
Vedolizumab 
Non-immunosuppressive biologic therapies may be used; the Sponsor Clinical Director must 
be consulted before use.
Advanced Immunosuppressive Small Molecule Medications
JAK inhibitors (JAK1, JAK2, JAK3 isoforms), PDE4 inhibitors, S1P modulators, and TYK2 
inhibitors are prohibited within 4 weeks prior to Randomization and throughout the study 
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until the last dose of study intervention. Examples of these medications include, but are not 
limited to, those in Table 9.
Table 9
Commonly Used Advanced Immunosuppressive Small Molecule Medications
JAK Inhibitors
PDE4 
Inhibitors
S1P 
Modulators
TYK2 
Inhibitors
Abrocitinib
Baricitinib
Delgocitinib
Fedratinib
Filgotinib
Oclacitinib
Pacritinib
Peficitinib
Ritlecitinib
Ruxolitinib
Tofacitinib
Upadacitinib
Apremilast
Cilomilast
Crisaborole
Ibudilast
Roflumilast
Fingolimod
Ozanimod
Ponesimod
Siponimod
Deucravacitinib
JAK = Janus kinase; PDE4 = phosphodiesterase 4; S1P = sphingosine 1-phosphate; TYK2 = tyrosine kinase 2.
Vaccines
It is recommended that participants be brought up-to-date with immunizations prior to 
Screening, in line with current local immunization guidelines.
Inactive (Non-Live) Vaccines
Administration of inactive (non-live) vaccines is permitted prior to and during the study 
according to local practice. Examples of common non-live vaccines include, but are not 
limited to, the following:
•
Injectable influenza vaccine
•
Pneumococcal vaccine
•
Shingrix (herpes zoster; recombinant, adjuvanted) vaccine
•
Pertussis (Tdap) vaccine
•
SARS-CoV-2 vaccine (inactivated, mRNA, RNA)
Live Vaccines
Administration of JYNNEOS (smallpox/mpox [also referred to as monkeypox] vaccine, live, 
non-replicating) is permitted.
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Except for JYNNEOS, other live vaccines are prohibited within 4 weeks (or longer if 
required locally) prior to Randomization and during the study until 6 weeks after the last 
dose of study intervention. Examples of prohibited live vaccines include, but are not limited 
to, the following:
•
Bacille Calmette-Guerin vaccine
•
Measles-mumps-rubella or measles-mumps-rubella-varicella vaccine
•
Monovalent live influenza A (H1N1) vaccine (intranasal)
•
Oral polio vaccine
•
Rotavirus vaccine
•
Seasonal trivalent live influenza vaccine (intranasal)
•
Smallpox vaccine
•
Typhoid vaccine (oral)
•
Varicella (chicken pox) vaccine
•
Yellow fever vaccine
•
Zostavax (herpes zoster, live attenuated) vaccine
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10.9
Appendix 9: Hypereosinophilic Syndrome or Eosinophil-Associated Organ 
Injury
Definition of Hypereosinophilic syndrome [Valent, P., et al 2012]
1. Absolute eosinophil count ≥1500 cell/µL on 2 examinations (interval ≥1 month*) and
2. Organ damage and/or dysfunction attributable to tissue hypereosinophilia† and
3. Exclusion of other disorders or conditions as major reason for organ damage
*
In the case of evolving life-threatening end-organ damage, the diagnosis can be made 
immediately to avoid delay in therapy.
†
HE-related organ damage: organ dysfunction with marked tissue eosinophil infiltrates 
and/or extensive deposition of eosinophil-derived proteins (in the presence or absence of 
marked tissue eosinophils) and 1 or more of the following: (1) fibrosis (lung, heart, 
digestive tract, skin and others); (2) thrombosis with or without thromboembolism; (3) 
cutaneous (including mucosal) erythema, edema/angioedema, ulcerations, pruritus, and 
eczema; and (4) peripheral or central neuropathy with chronic or recurrent neurologic 
deficit. Less commonly, organ damage in liver, pancreas, kidney, and other organs can be 
judged as HE-related pathology. HES can manifest in 1 or more organ systems.
Eosinophil-associated organ injury can also occur as single organ diseases. Table 10 provides 
a list of single-organ diseases accompanied by HE [Valent, P., et al 2012].
Table 10
Organ-Restricted (Inflammatory) Conditions Accompanied by 
Hypereosinophilia
Eosinophilic ascites
Eosinophilic nephritis
Eosinophilic asthma
Eosinophilic ocular disorders
Eosinophilic bronchitis
Eosinophilic pancreatitis
Eosinophilic colitis
Eosinophilic panniculitis
Eosinophilic cystitis
Eosinophilic pleuritis
Eosinophilic endometritis
Eosinophilic pneumonia
Eosinophilic esophagitis
Eosinophilic pustular folliculitis: all variants
Eosinophilic fasciitis (Shulman syndrome)
Eosinophilic synovitis
Eosinophilic gastroenteritis
Eosinophilic ulcer of the oral mucosa
Eosinophilic hepatitis
Eosinophilic vasculitis
Eosinophilic mastitis
Pachydermatous eosinophilic dermatitis
Eosinophilic myocarditis
Wells syndrome (eosinophilic cellulitis)
Eosinophilic myometritis
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10.10 Appendix 10: TB Risk Factor Assessment Questionnaire
For screening TB risk assessment, ask Part I and Part II questions.
For annual TB risk assessment, only ask the Part I questions.
Part I:
1. Has an immediate family member or other close contact been newly diagnosed with or 
treated for active or latent tuberculosis during the last 3 months?
2. Within the past year, have you or an immediate family member, had any of the following 
problems lasting for 3 weeks or longer which remained unexplained:
•
Chronic cough
•
Production of sputum
•
Blood-streaked sputum
•
Weight loss
•
Fever
•
Fatigue/tiredness
•
Night sweats
•
Shortness of breath
Part II:
1. Have you ever been diagnosed or treated for active or latent tuberculosis?
2. Have you lived in or had prolonged (>30 days) travels to any of the following high 
burden TB endemic regions? 
•
Angola 
•
Bangladesh
•
Brazil
•
Cambodia
•
Central African 
Republic
•
China
•
Congo
•
Democratic People's 
Republic of Korea
•
Democratic Republic 
of the Congo
•
Ethiopia
•
Gabon
•
India
•
Indonesia
•
Kenya
•
Lesotho
•
Liberia
•
Mongolia
•
Mozambique
•
Myanmar
•
Namibia
•
Nigeria
•
Pakistan
•
Papua New Guinea
•
Philippines
•
Russian Federation
•
Sierra Leone
•
South Africa
•
Thailand 
•
Uganda 
•
United Republic of 
Tanzania
•
Viet Nam
•
Zambia
•
Zimbabwe
3. Have you lived or worked in a prison, refugee camp, homeless shelter, immigration 
center, or nursing home?
https://www.cdc.gove/tb/topic/testing/diagnosingltbi.htm
Global tuberculosis report 2023 (who.int)
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10.11 Appendix 11: Abbreviations
Abbreviation
Expanded Term
Ab
antibody
ADA
antidrug antibodies
ADME
absorption, distribution, metabolism, and excretion
AE
adverse event
AEC
absolute eosinophil count
ALP
alkaline phosphatase
ALT
alanine aminotransferase
APaT
All-Participants-as-Treated
AR
adverse reaction
ART
antiretroviral therapy
AST
aspartate aminotransferase
BFNE
Brief Fear of Negative Evaluation
bid
twice daily
BP
blood pressure
BSA
body surface area
CBC
complete blood count
CCL22
chemokine ligand 22
CD4+
cluster differentiation 4 expressing cells
CD25
cluster of differentiation 25, IL-2Rα subunit
CD122
cluster differentiation 122, IL-2Rβ subunit
CFR
Code of Federal Regulations
CGI-C
Clinical Global Impression of Change
CGI-S
Clinical Global Impression of Severity
CI
confidence interval
Cmax
maximum concentration
CONSORT
Consolidated Standards of Reporting Trials
COVID-19
coronavirus disease 2019
CL
clearance
ClinROs
clinician reported outcomes
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Abbreviation
Expanded Term
CRF
Case Report Form
CSR
Clinical Study Report
CT
computer tomography
C-terminus
carboxyl-terminus
Ctrough
trough concentration
CXR
chest x-ray
DILI
drug-induced liver injury
DLQI
Dermatology Life Quality Index
DMC
Data Monitoring Committee
DNA
deoxyribonucleic acid
ECG
electrocardiogram
ECI
event of clinical interest
eCRF
electronic Case Report Form
EDC
electronic data collection
eDMC
External Data Monitoring Committee
eGFR
estimated glomerular filtration rate
ELISA
enzyme-linked immunosorbent assay
EMA
European Medicines Agency
EOC
Executive Oversight Committee
FAS
Full Analysis Set
FBR
future biomedical research
Fc
fragment crystallizable
FDA
Food and Drug Administration
FDAAA
Food and Drug Administration Amendments Act
FOXP3
forkhead box protein 3
FSH
follicle-stimulating hormone 
FTU
fingertip unit
F-VASI
Facial Vitiligo Area Scoring Index
GCP
Good Clinical Practice
GI
gastrointestinal
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Abbreviation
Expanded Term
GWAS
genome-wide association study
hCG
human chorionic gonadotropin
H1, (H2)
hypothesis 1, (hypothesis 2)
HBcAb
hepatitis B core antibody
HBsAg
hepatitis B surface antigen
HBV
hepatitis B virus
HCV
hepatitis C virus
HE
hypereosinophilia
HES
hypereosinophilic syndrome
HIV
human immunodeficiency virus
HR
heart rate
HRT
hormone replacement therapy
IA
interim analysis
IgG1
immunoglobulin G1
IL-2
interleukin 2
IL-2M
interleukin-2 mutein
IL-10
interleukin 10
IA
interim analysis(ses)
IB
Investigator’s Brochure
ICF
Informed Consent Form
ICH
International Council for Harmonisation of Technical Requirements for 
Pharmaceuticals for Human Use
ICMJE
International Committee of Medical Journal Editors
ID
identification
IEC
Independent Ethics Committee
Ig
immunoglobulin
IGRA
interferon-gamma release assay
IMP
investigational medicinal product
IND
Investigational New Drug
IRB
Institutional Review Board
IRT
interactive response technology
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Abbreviation
Expanded Term
IUD
intrauterine device
IUS
intrauterine hormone-releasing system
IV
intravenous
IVD
in vitro diagnostic
JAK
Janus kinase
JAKi
Janus kinase inhibitor
LDA
longitudinal data analysis
LLOQ
lower limit of quantitation
MAD
maximum administered dose
M&N
Mietinnen and Nurminen
MAR
missing-at-random
MCAR
missing completely at random
MDRD
Modification of Diet in Renal Disease
MedDRA
Medical Dictionary for Regulatory Activities
MI
multiple imputations
MNAR
missing not at random
mRNA
messenger RNA
NK
natural killer cells
N-terminus
amino-terminus
PBMC
peripheral blood mononuclear cell
PBO
placebo
PCR
polymerase chain reaction
PD
pharmacodynamic
PDE4
phosphodiesterase 4
PGIC/M
Patient Global Impression of Change/Meaningfulness
PGI-S
Patient Global Impression of Severity
PK
pharmacokinetic
po
orally
POCBP
participants of childbearing potential
PP
per-protocol
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Abbreviation
Expanded Term
PPD
purified protein derivative
PQC
product quality complaint
PRO
patient-reported outcome
Q2W
every 2 weeks
Q4W
every 4 weeks
QFT
QuantiFERON-TB Gold®
QoL
quality of life
RNA
ribonucleic acid
RR
respiratory rate
S1P
sphingosine 1-phosphate
SAC
Scientific Advisory Committee
SAE
serious adverse event
SAD
single ascending dose
SAP
Statistical Analysis Plan
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
SD
standard deviation
SGOT
serum glutamic oxaloacetic transaminase
SGPT
serum glutamic pyruvic transaminase
SLAB
supplemental laboratory test(s)
SNP
single-nucleotide polymorphism
SPF
sun protection factor
SoA
schedule of activities
SOP
Standard Operating Procedures
SUSAR
suspected unexpected serious adverse reaction
t½
half-life
TB
tuberculosis
TBNK
T, B, and natural killer cell surface marker assay
TC
telephone call
Tconv
conventional T cells, CD24+CD25-cells
Tdap
tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine
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Abbreviation
Expanded Term
Teff
effector T cell
Tmax
time to maximum concentration
Tregs
regulatory T cells
T-VASI
Total Vitiligo Area Scoring Index
TYK2
tyrosine kinase 2
UC
ulcerative Colitis
ULN
upper limit of normal
VASI
Vitiligo Area Scoring Index
VitiQoL
Vitiligo-Specific Quality of Life Instrument
VNS
Vitiligo Noticeability Scale
VS
vital signs
WBC
white blood cell
WT
wild type
CCI
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11
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Fanton C, Furie R, Dixit N, Haglund C, Lu 
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