A Phase 2 Clinical Trial of Tolebrutinib, a Brain-penetrant Bruton's Tyrosine Kinase Inhibitor, for the Modulation of Chronically Inflamed White Matter Lesions in Multiple Sclerosis
Phase: PHASE2
Conditions: Multiple Sclerosis
Sponsor: National Institute of Neurological Disorders and Stroke (NINDS)

The attached includes: 
 
Protocol:  A Phase 2 clinical trial of tolebrutinib, a brain-penetrant Bruton’s tyrosine kinase 
inhibitor, for the modulation of chronically inﬂamed white matter lesions in multiple 
sclerosis 
• Statistical Analysis Plan included within the protocol 
 
NCT#:  04742400 
 
Document Date:  November 3, 2023 

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Abbreviated Title: BRaKe-MS 
 
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1 
 
Abbreviated Title: BRaKe-MS 
NIH IRB #: 21N0010 
Version Date: 11/3/2023 
Title: A Phase 2 clinical trial of tolebrutinib, a brain-penetrant Bruton’s tyrosine kinase inhibitor, for the 
modulation of chronically inflamed white matter lesions in multiple sclerosis 
 
Principal Investigator: 
Daniel Reich, MD, PhD 
National Institute of Neurological Disorders and Stroke  
Building 10, Rm 5C103 
9000 Rockville Pike 
Bethesda, MD 20892 
Phone: 301-496-1801 
E-mail: daniel.reich@nih.gov 
Investigational Agent: 
 
Drug Name: 
tolebrutinib 
IND Number: 
153292 
Sponsor: 
NINDS 
Manufacturer: 
Sanofi Genzyme/TDR17022 
 
 

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2 
TABLE OF CONTENTS 
STATEMENT OF COMPLIANCE .............................................................................................. 6 
1 
PROTOCOL SUMMARY .................................................................................................... 7 
1.1 
SYNOPSIS ..................................................................................................................... 7 
1.2 
SCHEMA ....................................................................................................................... 9 
1.3 
SCHEDULE OF ACTIVITIES (SOA) ......................................................................... 10 
2 
INTRODUCTION ............................................................................................................... 13 
2.1 
STUDY RATIONALE ................................................................................................. 13 
2.2 
BACKGROUND .......................................................................................................... 13 
2.2.1 
Rationale for studying chronic active MS lesions ................................................. 13 
2.2.2 
Role of BTK in MS pathogenesis ......................................................................... 15 
2.2.3 
BTK inhibitors ...................................................................................................... 16 
2.2.4 
Tolebrutinib ........................................................................................................... 16 
2.2.5 
Co-treatment with anti-CD20 monoclonal antibodies .......................................... 18 
2.2.6 
Importance of this study ........................................................................................ 19 
2.2.7 
Rationale for outcome measures ........................................................................... 20 
2.3 
RISK/BENEFIT ASSESSMENT ................................................................................. 20 
2.3.1 
Known Potential Risks .......................................................................................... 20 
2.3.2 
Known Potential Benefits ...................................................................................... 27 
2.3.3 
Assessment of Potential Risks and Benefits ......................................................... 27 
3 
OBJECTIVES AND ENDPOINTS .................................................................................... 28 
4 
STUDY DESIGN ................................................................................................................ 29 
4.1 
OVERALL DESIGN .................................................................................................... 29 
4.2 
SCIENTIFIC RATIONALE FOR STUDY DESIGN .................................................. 30 
4.3 
JUSTIFICATION FOR DOSE ..................................................................................... 30 
5 
STUDY POPULATION ..................................................................................................... 31 
5.1 
INCLUSION CRITERIA ............................................................................................. 31 
5.1.1 
Tolebrutinib Cohorts Inclusion Criteria ................................................................ 31 
5.1.2 
Control Cohort Inclusion Criteria ......................................................................... 32 
5.2 
EXCLUSION CRITERIA ............................................................................................ 32 
5.2.1 
Tolebrutinib Cohorts Exclusion Criteria ............................................................... 32 
5.2.2 
Control Cohort Exclusion Criteria ........................................................................ 34 
5.3 
INCLUSION OF VULNERABLE PARTICIPANTS .................................................. 34 

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3 
5.3.1 
Participation of NIH Staff of family members of study team members ............... 35 
5.4 
INCLUSION OF PREGNANT WOMEN, FETUSES OR NEONATES .................... 35 
5.5 
LIFESTYLE CONSIDERATIONS .............................................................................. 35 
5.6 
SCREEN FAILURES ................................................................................................... 36 
5.7 
STRATEGIES FOR RECRUITMENT AND RETENTION ....................................... 36 
5.7.1 
Costs ...................................................................................................................... 36 
5.7.2 
Compensation ........................................................................................................ 36 
6 
STUDY INTERVENTION ................................................................................................. 37 
6.1 
STUDY INTERVENTIONS(S) ADMINISTRATION ................................................ 37 
6.1.1 
Study Intervention Description ............................................................................. 37 
6.1.2 
Dosing and Administration ................................................................................... 38 
6.2 
PREPARATION/HANDLING/STORAGE/ACCOUNTABILITY ............................ 39 
6.2.1 
Acquisition and Accountability ............................................................................. 39 
6.2.2 
Formulation, Appearance, Packaging, and Labeling ............................................ 39 
6.2.3 
Product Storage and Stability ................................................................................ 39 
6.2.4 
Preparation ............................................................................................................ 39 
6.3 
MEASURES TO MINIMIZE BIAS: RANDOMIZATION AND BLINDING .......... 39 
6.4 
STUDY INTERVENTION COMPLIANCE ............................................................... 39 
6.5 
CONCOMITANT THERAPY ..................................................................................... 39 
7 
STUDY INTERVENTION DISCONTINUATION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL ........................................................................... 40 
7.1 
DISCONTINUATION OF STUDY INTERVENTION .............................................. 40 
7.1.1 
Definitive discontinuation ..................................................................................... 40 
7.1.2 
Temporary discontinuation ................................................................................... 41 
7.2 
PARTICIPANT DISCONTINUATION/WITHDRAWAL FROM THE STUDY ...... 41 
7.3 
LOST TO FOLLOW-UP .............................................................................................. 41 
8 
STUDY ASSESSMENTS AND PROCEDURES .............................................................. 41 
8.1 
SCREENING PROCEDURES ..................................................................................... 41 
8.2 
EFFICACY ASSESSMENTS ...................................................................................... 42 
8.2.1 
Clinical Evaluations .............................................................................................. 42 
8.2.2 
Biospecimen Evaluations ...................................................................................... 42 
8.2.3 
Correlative Studies for Research ........................................................................... 42 
8.2.4 
Samples for Genetic/Genomic Analysis ............................................................... 42 

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4 
8.3 
SAFETY AND OTHER ASSESSMENTS .................................................................. 42 
8.4 
ADVERSE EVENTS AND SERIOUS ADVERSE EVENTS .................................... 44 
8.4.1 
Definition of Adverse Event ................................................................................. 44 
8.4.2 
Definition of Serious Adverse Events (SAE) ........................................................ 44 
8.4.3 
Classification of an Adverse Event ....................................................................... 44 
8.4.4 
Time Period and Frequency for Event Assessment and Follow-Up ..................... 45 
8.4.5 
Adverse Event Reporting ...................................................................................... 46 
8.4.6 
Serious Adverse Event Reporting ......................................................................... 46 
8.4.7 
Events of Special Interest ...................................................................................... 46 
8.4.8 
Reporting of Pregnancy ......................................................................................... 47 
8.5 
UNANTICIPATED PROBLEMS ................................................................................ 47 
8.5.1 
Definition of Unanticipated Problems (UP) .......................................................... 47 
8.5.2 
Unanticipated Problem Reporting ......................................................................... 47 
8.5.3 
NIH Intramural IRB Reporting of IND Safety Reports ........................................ 47 
9 
STATISTICAL CONSIDERATIONS ................................................................................ 47 
9.1 
STATISTICAL HYPOTHESIS ................................................................................... 47 
9.2 
SAMPLE SIZE DETERMINATION ........................................................................... 47 
9.3 
POPULATIONS FOR ANALYSES ............................................................................ 48 
9.3.1 
Evaluable for toxicity ............................................................................................ 48 
9.3.2 
Evaluable for objective response ........................................................................... 48 
9.3.3 
Evaluable Non-Target Disease Response ............................................................. 48 
9.4 
STATISTICAL ANALYSES ....................................................................................... 48 
9.4.1 
General Approach ................................................................................................. 48 
9.4.2 
Analysis of the Primary Endpoint ......................................................................... 48 
9.4.3 
Analysis of the Secondary Endpoints .................................................................... 48 
9.4.4 
Safety Analyses ..................................................................................................... 49 
9.4.5 
Baseline Descriptive Statistics .............................................................................. 49 
9.4.6 
Planned Interim Analyses ...................................................................................... 49 
9.4.7 
Subgroup Analyses ................................................................................................ 49 
9.4.8 
Tabulation of Individual Participant Data ............................................................. 49 
9.4.9 
Exploratory Analyses ............................................................................................ 49 
10 REGULATORY AND OPERATIONAL CONSIDERATIONS ....................................... 49 
10.1 INFORMED CONSENT PROCESS ........................................................................... 49 

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5 
10.1.1 Consent/Assent Procedures and Documentation ................................................... 49 
10.1.2 Consent for minors when they reach the age of majority ..................................... 50 
10.1.3 Considerations for Consent of NIH staff, or family members of study team 
members ................................................................................................................ 50 
10.1.4 Consent of subjects who are, or become, decisionally impaired .......................... 50 
10.2 STUDY DISCONTINUATION AND CLOSURE ...................................................... 51 
10.3 CONFIDENTIALITY AND PRIVACY ...................................................................... 51 
10.4 FUTURE USE OF STORED SPECIMENS AND DATA ........................................... 52 
10.5 SAFETY OVERSIGHT ............................................................................................... 52 
10.6 CLINICAL MONITORING ......................................................................................... 52 
10.6.1 Independent Hepatology Assessment Committee (HAC) ..................................... 53 
10.7 QUALITY ASSURANCE AND QUALITY CONTROL ........................................... 53 
10.8 DATA HANDLING AND RECORD KEEPING ........................................................ 53 
10.8.1 Data Collection and Management Responsibilities .............................................. 53 
10.8.2 Study Records Retention ....................................................................................... 54 
10.9 PROTOCOL DEVIATIONS AND NON-COMPLIANCE ......................................... 54 
10.9.1 NIH Definition of Protocol Deviation ................................................................... 54 
10.10 PUBLICATION AND DATA SHARING POLICY .................................................... 54 
10.10.1 Human Data Sharing Plan ..................................................................................... 54 
10.10.2 Genomic Data Sharing Plan .................................................................................. 55 
10.11 COLLABORATIVE AGREEMENTS ......................................................................... 55 
10.11.1 Agreement Type .................................................................................................... 55 
10.12 CONFLICT OF INTEREST POLICY ......................................................................... 55 
11 ABBREVIATIONS ............................................................................................................. 55 
12 APPENDIX ......................................................................................................................... 59 
12.1 APPENDIX 1: MEDICATIONS THAT CANNOT BE TAKEN WITH 
TOLEBRUTINIB ......................................................................................................... 59 
12.2 APPENDIX 2: Adverse Events of Special Interest (AESI) ......................................... 61 
13 REFERENCES .................................................................................................................... 62 
 
 
 

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6 
STATEMENT OF COMPLIANCE 
The trial will be carried out in accordance with International Conference on Harmonisation Good Clinical 
Practice (ICH GCP) and the following: 
• 
United States (US) Code of Federal Regulations (CFR) applicable to clinical studies (45 CFR 
Part 46, 21 CFR Part 50, 21 CFR Part 56, 21 CFR Part 312, and/or 21 CFR Part 812) 
National Institutes of Health (NIH)-funded investigators and clinical trial site staff who are responsible 
for the conduct, management, or oversight of NIH-funded clinical trials have completed Human Subjects 
Protection and ICH GCP Training. 
The protocol, informed consent form(s), recruitment materials, and all participant materials will be sub-
mitted to the Institutional Review Board (IRB) for review and approval. Approval of both the protocol 
and the consent form must be obtained before any participant is enrolled. Any amendment to the protocol 
will require review and approval by the IRB before the changes are implemented to the study. In addition, 
all changes to the consent form will be IRB-approved; an IRB determination will be made regarding 
whether a new consent needs to be obtained from participants who provided consent, using a previously 
approved consent form. 
 
 

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7 
1 
PROTOCOL SUMMARY 
1.1 
SYNOPSIS 
Title: A Phase 2 trial of the effect of tolebrutinib, a brain-penetrant Bruton’s tyrosine kinase inhibitor, on 
chronically inflamed white matter lesions in multiple sclerosis 
 
Study Description: 
The primary goal of this protocol is to test whether 48 weeks of treatment with 
tolebrutinib, an investigational, orally available, brain-penetrant, Bruton’s tyrosine kinase (BTK) inhibi-
tor, affects an imaging marker (the “paramagnetic rim”) associated with chronically inflamed white mat-
ter lesions in multiple sclerosis (MS). In this rater-blinded but otherwise open- label study, 16 adults 
with MS who are on stable disease-modifying treatment with anti-CD20 antibody therapy and are within 
6 months of their most recent dose, have at least one paramagnetic rim lesion on 7-tesla magnetic reso-
nance imaging (MRI), and have developed no new white matter lesions or clinical relapses for at least 6 
months, will initiate treatment with tolebrutinib and agree to forego further anti-CD20 or other disease-
modifying therapy for the duration of the trial. 
An initial 7 enrolled study participants started tolebrutinib at 60 mg/day (“Initial Cohort”). Of the Initial 
Cohort, participants (n=3), who had initiated tolebrutinib 60 mg will remain at 60 mg and not be esca-
lated to 120 mg/day. The remaining participants (n=4) consented to Cohort A, who had initiated tolebru-
tinib 60 mg and previously escalated to 120 mg/day will remain at that dose.  
Radiological, clinical, and biological outcomes are measured at 24, 48, 72, 96, and 144 (Cohort A) weeks, 
with additional interspersed visits for safety monitoring. Participants may subsequently continue treatment 
until tolebrutinib is marketed or commercial development halted. A comparison group of 10 participants 
who meet enrollment criteria but choose to stay on anti-CD20 therapy will also be enrolled. The primary 
outcome measure is disappearance of one or more paramagnetic rims from white matter lesions identified 
at baseline. Secondary outcomes include safety and tolerability and additional radiological outcomes. Ex-
ploratory clinical, radiological, and laboratory investigations are planned to study the mechanism of action 
of tolebrutinib and for biomarker development, and to compare the tolebrutinib and anti-CD20 cohorts. 
Objectives: 
Primary Objective: To evaluate the effects of 48 weeks of tolebrutinib 60 mg/day treatment 
on the paramagnetic rim of chronically inflamed white matter lesions, as seen on 7-tesla MRI. 
Secondary Objectives: (1) To assess safety and tolerability of 48 weeks of treatment with tolebrutinib 60 
mg and 96 weeks of treatment with tolebrutinib 120 mg (Cohort A) all following anti-CD20 antibody 
therapy. (2) To assess the possible repair of chronically inflamed white matter lesions in which inflamma-
tion at the lesion edge has been modulated by tolebrutinib. 
Endpoints: 
Primary Endpoint: Per-patient proportion of lesions in which the paramagnetic rim has 
disappeared at the end of 48 weeks of tolebrutinib 60 mg. 
Secondary Endpoints: (1) Adverse event tables. (2) Changes in T1 relaxation time within paramagnetic 
rim lesions at the end of 96 weeks of tolebrutinib 120 mg, relative to non-rim lesions. (3) Changes in size 
of paramagnetic rim lesions at the end of 96 weeks of tolebrutinib 120 mg, relative to non-rim lesions. 
Study Population: 
Up to 10 adults with multiple sclerosis, targeting at least 7 participants who com-
plete 48 weeks of therapy with tolebrutinib 60 mg in Cohort A. Up to 10 adults with multiple sclerosis 
who meet inclusion criteria but choose to stay on anti-CD20 therapy. 
Phase: 
2 
Description of Study Intervention: 
Oral tolebrutinib 60 mg per day for 48 weeks (Initial Cohort), and 
a subgroup of patients already escalated to 120 mg (Cohort A), with optional long-term extension and 
follow-up. 
Study Duration: 
5 years 

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8 
Participant Duration: 144 weeks (Cohort A) for primary and secondary outcomes, with optional long-
term extension and follow-up.

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9 
1.2 
SCHEMA 
Control: 
 
 
Initial Cohort (tolebrutinib 60 mg) 
Cohort A (tolebrutinib 60 mg → 120 mg)#:
# See section 6.1.2.5. Participants (n=4) in cohort A, who had initiated tolebrutinib 60mg and previously escalated to 120 mg/ day will remain at that dose and the 3 remaining participants, in the initial 
cohort, who initiated tolebrutinib 60mg will remain at 60mg and not be escalated to 120mg/day. 
Week 24 
(±28 days)
• History
• Exam
• Scales
• 7T MRI
• Bloodwork
Week 48 
(±28 days)
• History
• Exam
• Scales
• 7T MRI
• Bloodwork
• LP optional
Treatment: 
Anti-CD20 therapy
Week 72 
(±28 days)
• History
• Exam
• Scales
• 7T MRI
• Bloodwork
Day 0
• 7T MRI
Week 96 
(±28 days)
• History
• Exam
• Scales
• 7T MRI
• Bloodwork
Baseline 
(Within 24 weeks of Day 0)
• History
• Exam
• Scales
• Bloodwork
• LP (optional)
Treatment:
anti-CD20 for 
>6 months

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1.3 
SCHEDULE OF ACTIVITIES (SOA) 
Initial cohort (participants who choose not to escalate dose from tolebrutinib 60 mg): 
Procedures 
Baseline (≤14 days prior 
to Day 0)
Day 0 
24 – 48 Hours 
Follow-Up 
Week 2 (±7 days) 
Week 4 (±7 days) 
Week 6 (±7 days) 
Week 8 (±7 days) 
Week 10 (±7 days) 
Week 12 (±7 days) 
Week 24 (±14 days) 
Week 36 (±14 days) 
Week 48 (±14 days) 
Week 60 (±14 days) 
Week 72 (±14 days) 
Week 84 (±14 days) 
Week 96 (±14 days) 
Every 24 weeks (±28 
days)* 
Informed consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Interval history/neurological exam 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Vital signs 
X 
X 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Clinical measures  
(EDSS, 9HPT, 25FTW, SNRS, SDMT) 
X 
 
 
 
 
 
 
 
 
X 
 
X 
 
X 
 
X 
X 
Clinical labs 
X 
 
 
X2 
X1 
X2 
X1 
X2 
X2 
X 
X2 
X 
X2 
X 
X2 
X 
X 
Research labs 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Pregnancy test (if applicable) 
X 
X 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Brain MRI (7-tesla) 
X 
 
 
 
 
 
 
 
 
X 
 
X 
 
X 
 
X 
X 
Brain MRI 
 
 
 
 
 
 
 
 
X 
 
X 
 
X 
 
X 
 
 
ECG 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Lumbar puncture 
X 
 
 
 
 
 
 
 
X 
 
 
X 
 
 
 
 
 
 
Tolebrutinib first dose 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Follow-up phone call 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Tolebrutinib study drug dispensed 
 
X 
 
 
 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
*Long term extension until tolebrutinib is marketed or until its development is halted. 
1Safety labs. 
2Liver-specific safety labs (AST, ALT, alkaline phosphatase, total bilirubin) 
 
 

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Cohort A (tolebrutinib 60 mg → 120 mg)#: 
Procedures 
Baseline (≤14 days 
i
t D
0)
Day 0 
24 – 48 Hours 
Follow-Up 
Week 2 (±7 days) 
Week 4 (±7 days) 
Week 6 (±7 days) 
Week 8 (±7 days) 
Week 10 (±7 days) 
Week 12 (±7 days) 
Week 24 (±14 days) 
Week 36 (±14 days) 
Week 48 (±14 days) 
Week 48+24-48 hours
Week 52 (±7 days) 
Week 56 (±7 days) 
Week 60 (±14 days) 
Week 72 (±14 days) 
Week 84 (±14 days) 
Week 96 (±14 days) 
Week 108 (±14 days) 
Week 120 (±14 days) 
Week 132 (±14 
d
)
Week 144 (±14 
d
)
Every 24 weeks (±28 
d
)*
Informed consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Interval history/neurological 
exam 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Vital signs 
X 
X 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Clinical measures  
(EDSS, 9HPT, 25FTW, SNRS, 
SDMT) 
X 
 
 
 
 
 
 
 
 
X 
 
X 
 
 
 
 
X 
 
X 
X 
X 
X 
X 
X 
Clinical labs 
X 
 
 
X2 
X1 
X2 
X1 
X2 
X1 
X 
X1 
X 
 
X1 
X1 
X1 
X 
X1 
X 
X1 
X 
X1 
X 
X 
Research labs 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Pregnancy test (if applicable) 
X 
X 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Brain MRI (7-tesla) 
X 
 
 
 
 
 
 
 
 
X 
 
X 
 
 
 
 
X 
 
X 
 
X 
 
X 
X 
Brain MRI  
 
 
 
 
 
 
 
 
X 
 
X 
 
 
 
 
X 
 
X 
 
X 
 
X 
 
 
ECG 
X 
 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Lumbar puncture 
X 
 
 
 
 
 
 
 
X 
 
 
X 
 
 
 
 
 
 
X 
 
 
 
 
 
Tolebrutinib first dose at each 
dose level 
 
X 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Follow-up phone call 
 
 
X 
 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
Tolebrutinib study drug dispensed 
 
X 
 
 
 
 
 
 
X 
X 
X 
X 
 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
*Long term extension until tolebrutinib is marketed or until its development is halted. 
# See section 6.1.2.5. Participants (n=4) in cohort A, who had initiated tolebrutinib 60mg and previously escalated to 120 mg/ day will remain at 
that dose and the 3 remaining participants in the initial cohort, who initiated tolebrutinib 60mg will remain at 60mg and not be escalated to 
120mg/day. 
1Safety labs. 
2Liver-specific safety labs (AST, ALT, alkaline phosphatase, total bilirubin) 
 

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Comparison cohort (anti-CD20 therapy only):  
Procedures 
Baseline (≤14 days prior to Day 
0)
Day 0 
Week 24 (±14 days) 
Week 48 (±14 days) 
Week 72 (±14 days) 
Week 96 (±14 days) 
Informed consent 
X 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
Interval history/neurological exam 
X 
 
X 
X 
X 
X 
Vital signs 
X 
X 
X 
X 
X 
X 
Clinical measures  
(EDSS, 9HPT, 25FTW, SNRS, SDMT) 
X 
 
X 
X 
X 
X 
Clinical labs 
X 
 
X 
X 
X 
X 
Research labs 
X 
 
X 
X 
X 
X 
Pregnancy test (if applicable) 
 
X 
X 
X 
X 
X 
Brain MRI (7-tesla) 
 
X 
X 
X 
X 
X 
Lumbar puncture 
X 
 
 
X 
 
 
 

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2 
INTRODUCTION 
2.1 
STUDY RATIONALE 
The purpose of this protocol is to test whether short-term treatment with tolebrutinib (previously 
SAR442168), an investigational, orally available, brain-penetrant, Bruton’s tyrosine kinase (BTK) inhib-
itor, affects an imaging marker (the “paramagnetic rim”) associated with chronically inflamed (“chronic 
active” or “smoldering”) white matter lesions in multiple sclerosis (MS). Clinical, radiological, and neu-
ropathological data have indicated that such lesions are associated with, and potentially cause, long-term 
disability progression in MS, an aspect of the disease for which current treatments are gravely inadequate. 
2.2 
BACKGROUND 
Section 2.2.1 begins with a general overview of the rationale for studying chronic active MS lesions and 
the advantages of approaching this study with ultra-high-field (7T) MRI. In Section 2.2.2, we discuss the 
role of BTK in MS pathogenesis. Section 2.2.3 discusses BTK inhibitors as a therapeutic class, Section 
2.2.4 the BTK inhibitor tolebrutinib, Section 2.2.5 the co-treatment with anti-CD20 monoclonal antibod-
ies, Section 2.2.6 the importance of this study, and Section 2.2.7 the rationale for our exploratory outcome 
measures. 
2.2.1 Rationale for studying chronic active MS lesions 
MS is a chronic immune-mediated disorder of the brain, spinal cord, and optic nerves.1 Since the early 
1980s,2 MRI has been used as a valuable tool for diagnosing and monitoring MS.3,4 Moreover, the path-
ognomonic focal demyelinating plaques, also termed “lesions,” have been the subject of intense clinical 
and imaging research interest in MS. 
It is widely accepted in the scientific community that newly forming demyelinating lesions are associated 
with inflammation and the short-term, abrupt opening of the blood-brain barrier (BBB) at the level of 
medium and small-caliber parenchymal veins.5 The imaging correlate of these changes is the leakage of a 
peripherally injected gadolinium-based MRI contrast agent into the parenchyma surrounding the inflamed 
venule. In our earlier studies, we were able to image this dynamic process at high resolution, and we 
termed it “centrifugal enhancement.”6,7 We described subsequent changes in the BBB in capillaries and 
venules at the lesion’s leading edge as “centripetal enhancement” (previously termed “ring” or “rim en-
hancement” in non-dynamic MRI acquisitions). 
A reasonable hypothesis based on available data is that centripetal contrast enhancement is best considered 
as a manifestation of the immune response to focal inflammatory demyelination in new MS plaques. Met-
aphorically, this process can be thought of as a “controlled burn,” in which inflammation is used to counter 
inflammation as part of normal wound healing.8,9 However, such controlled inflammation might also turn 
detrimental. Indeed, we have evidence that inflammation of this type can sometimes result in a persistent 
paramagnetic rim at the lesion edge, visualizable on MRI scans generated from the phase of the signal 
obtained via a T2*-weighted gradient-echo pulse sequence at 7T.10 Persistent paramagnetic rims develop 
more commonly in lesions that form in older people (Figure 1),11 consistent with laboratory data suggest-
ing that inflammatory cell- mediated remyelination becomes progressively less successful with age.12,13 
They are typically established within 3–6 months of initial demyelination and BBB opening and can be 
distinguished radiologically from lesions that repair. Indeed, through our in vivo and postmortem investi-
gations, we have found that paramagnetic-rim lesions are associated with extensive intralesional tissue 
damage (based on measurement of the T1 relaxation time by MRI), failed repair, apparently permanent 
demyelination, and a more pro-inflammatory peripheral blood cytokine and chemokine profile at base-
line.11 

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Over the past decade, data from our 
group and several additional labs have 
converged to indicate that the patho-
logical basis of the paramagnetic rim 
is iron accumulation within activated 
macrophages and/or microglia at the 
lesion rim, which is visible on 7T 
MRI.11,14,15 These rims can be long-
lasting16,17 (potentially for several dec-
ades), and pathologically they mark 
the class of chronically inflamed le-
sions known, variously, as “chronic 
active,” 
“slowly 
expanding,” 
or 
“smoldering” (Figure 2). Such lesions make up approximately 15–25% of white matter lesions in MS, and 
while they may occur even in cases of asymptomatic MS, they are substantially more common in 
longstanding, clinically progressive disease.18 
At 7T, the intra-rater and inter-rater agreement is on the order of 85–90%, with Cohen’s κ on the order of 
0.75.19 Indeed, in our recent clinical data, we showed that the majority of adults with MS have at least one 
rim lesion, and that those with 4 or more rim lesions reach motor and cognitive disability at an earlier age. 
Figure 1. Semi logarithmic plot of the longitudinal volume for each lesion ac-
cording to participant age and lesion group (centripetal with persistent para-
magnetic rim and centripetal with transient paramagnetic rim).11 
Figure 2. A, In vivo 7T axial phase magnetic resonance imaging (MRI) acquired at age 59 years showing representative su-
pratentorial rim lesions; magnified views are in the insets. B, Histogram of the 10 rim lesions analyzed by MRI and histopathol-
ogy. The lesion area was measured on in vivo coregistered T1-weighted scans at ages 52 and 59 years. All 10-rim lesions ex-
panded over 7 years. C, MRI-histopathology comparison of individual rim lesion evolution and pathology. Serial in vivo coronal 
T1-weighted MRI scans and relative patient age are shown in the first row of each section. Clearly expanding confluent areas are 
indicated by arrowheads. All expanding rim lesions were chronic-active by pathology results. An accumulation of iron-laden 
phagocytes (cluster of differentiation [CD] 68 and iron staining) was seen at the lesion edge (asterisks on myelin proteolipid pro-
tein [PLP] immunohistochemistry). From Absinta et al. (2019).20 

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Moreover, whereas rimless lesions shrink over time (−3.6%/year), rim lesions are stable in size or ex-
panded (2.2%/year; p<0.001).20 Pathologically, rim lesions show evidence of ongoing myelin destruction 
at the lesion edge, even in lesions that may have been present for decades. Stopping the adverse inflam-
mation in such lesions, potentially opening the door for remyelination, is therefore an important treatment 
target, for which none of the existing MS drugs is known to be effective. 
2.2.2 Role of BTK in MS pathogenesis 
BTK is expressed in several cell types that are known to be relevant in MS pathogenesis, most prominently 
B cells and macrophages.21 Although MS and its animal model, experimental autoimmune encephalomy-
elitis (EAE), are thought by most to be driven by T cells (which do not express BTK), B cells have rela-
tively recently been recognized as essential in the genesis of inflammatory demyelination, most likely by 
presenting antigen to T cells and/or cytokine production rather than through antibody production per se. 
Indeed, depleting B cells via the CD20 receptor is among the most potent MS therapies available today. 
Anti-CD20 therapy with ocrelizumab, a humanized anti-CD 20 monoclonal antibody, prevents >90% of 
new inflammatory demyelinating white matter lesions and can slow disability progression in some cases 
of primary progressive MS.22,23 Moreover, studies in both EAE24 and MS,25 including our group’s work 
using single-cell transcriptomic approaches,17 have confirmed that BTK inhibition is a promising thera-
peutic strategy. 
Immunologically, BTK is involved in cell signaling downstream of the B cell and Fcγ receptors, and the 
latter function is thought to be important for the action of BTK in microglia, the resident immune cells of 
the central nervous system (CNS) parenchyma.26 Hence, BTK inhibition by a CNS-penetrant small mole-
cule is a reasonable strategy for curtailing deleterious microglial activation, which occurs in chronic active 
white matter lesions (see Section 2.2.1). Indeed, preclinical studies, including in animal models of MS, 
show that BTK inhibition can alter the microglial transcriptional signature.27 Moreover, immunohisto-
chemical evaluation shows that some microglia at the edge of chronic active lesions express BTK (Figure 
3A) as well as elevated levels of the gene encoding Fcγ receptors.17 
In this study, the effects of 
BTK inhibition on B cells 
are potentially less relevant 
than the effects on myeloid 
cells and microglia, since 
we are studying patients 
who have been taking anti-
CD20 antibody therapy 
and have not shown evi-
dence of new white matter 
lesion formation, for at 
least 6 months. However, 
as anti-CD20 antibody therapy (which in intravenous form is dosed every 6 months) effectively depletes 
B cells in the periphery but is not sustained in the CNS,28 the action of tolebrutinib on CNS B cells may 
also prove highly relevant. Such B cells can indeed be found in perivascular spaces surrounding chronic 
active lesions (Figure 3B). 
Interestingly, both B cells and microglia appear to be relevant for the induction and sustenance of orga-
nized or semi-organized inflammatory foci in the leptomeninges, in part by contributing to the extensive 
subpial cortical demyelination that is found in many cases at biopsy and autopsy, and on MRI.29–31 These 
foci are also thought to 
play a role in progressive 
MS, but they are not as 
well seen on MRI as 
Figure 3. (A) Chromogenic immunohistochemistry showing cells at the inflammatory edge of 
a chronic active lesion, with morphology of activated microglia, that express BTK. NAWM, 
normal appearing white matter. (B) Multiplex immunofluorescence at the edge of a chronic ac-
tive lesion showing the presence of CD20+ B cells in perivascular spaces, mostly just outside 
the demyelinated area. Unpublished data, Translational Neuroradiology Section, NINDS. 

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chronic active white matter lesions, and as such they will only be evaluated in an exploratory fashion in 
this study. Nonetheless, it is important to remember that centrally acting BTK inhibitors may have an 
impact on leptomeningeal foci. 
2.2.3 BTK inhibitors 
Existing BTK inhibitors limit activation, maturation, and proliferation of B cells and other BTK- express-
ing immune cells by interfering with critical signaling cascades, as discussed in Section 2.2.2. They also 
interfere with differentiation of B cells into antibody-secreting plasma cells. Because BTK is constantly 
synthesized and BTK inhibition does not deplete B cells, treatment with BTK inhibitors — even covalently 
binding inhibitors such as tolebrutinib — is reversible (unlike anti-CD20 antibody treatment). BTK inhib-
itors have received FDA approval in oncology (chronic lymphocytic leukemia, mantle cell lymphoma, and 
Waldenström’s macroglobulinemia for ibrutinib, a first-generation BTK inhibitor, and mantle cell leuke-
mia for acalabrutinib, a second-generation BTK inhibitor). 
Well-known adverse reactions for both first- and second-generation BTK inhibitors include hemorrhage 
(grade 3 or higher in 2–3% of patients, thought to be related to platelet inhibition), infection (grade 3 or 
higher in 15–30% of patients), cytopenias (grade 3 or higher in up to 30% of patients), and atrial arrhyth-
mias (3–4% of patients per year). It is possible that some of these adverse reactions are related to off-target 
effects on other kinases. 
No BTK inhibitors have yet been approved for treatment of MS. In 2019, results of a double-blind, pla-
cebo-controlled Phase 2 trial in relapsing MS of a third-generation BTK inhibitor, evobrutinib, were re-
ported.25 The results suggested that this therapeutic strategy has similar efficacy to an FDA- approved oral 
disease-modifying treatment, dimethyl fumarate, with respect to reduction of MS relapses and new white 
matter lesions. However, unlike tolebrutinib, evobrutinib does not cross the blood-brain barrier, so its 
therapeutic effect most likely resulted from direct effects on adaptive immunity, and in particular B cell 
functioning, in the periphery. The evobrutinib trial also showed asymptomatic and reversible elevation of 
hepatic and pancreatic enzymes. As discussed in Section 2.2.4 , no treatment-emergent serious adverse 
reactions have been observed in individuals treated with tolebrutinib, despite specific monitoring. 
2.2.4 Tolebrutinib 
The material in this section is largely abstracted from the tolebrutinib (previously SAR442168) Investiga-
tor’s Brochure (IB), 11th Edition (March 2, 2023), which is provided as an appendix to this protocol. Unless 
otherwise specified, quotes are taken directly from the IB. 
“Tolebrutinib is an investigational, orally administered, small molecule that binds covalently to Bruton’s 
tyrosine kinase (BTK)…. Tolebrutinib demonstrates selectivity for BTK and a few related kinases that 
contain a homologous cysteine residue (Cys-481)… Tolebrutinib inhibits BTK, forming an irreversible 
bond near the ATP-binding site, rendering the kinase non-reactive with respect to signaling…. Tolebru-
tinib 60 mg tablets should be administered orally once per day with food…”  
2.2.4.1 Preclinical studies 
Extensive preclinical work evaluated its safety and pharmacokinetic (PK) properties in a number of animal 
models, including mice, rats, dogs, and rabbits; these data are summarized on pp. 13–17 of the IB. Notable 
points are the following: 
• 
Dose-dependent activity in two inflammatory models (Arthus reaction model in rats and experi-
mental autoimmune encephalomyelitis in mice). 
• 
No cardiovascular or respiratory effects at the highest doses in dogs. 
• 
Cmax reached in ~30 min in rats and ~90 min in dogs, bioavailability in the range of 20– 85%, 
volume of distribution on the order of 1.65 L/kg, and protein binding on the order of 85–95%. 
• 
CSF-to-plasma ratio of ~0.3 in rats. 
• 
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• 
No-adverse-event-effect levels (NOAEL) at the highest doses tested in 14-day and 13-week stud-
ies in rats and dogs, 28-day studies in rats, and 9-month studies in dogs. 
• 
In a 6-month rat study, a low-observed-adverse-effect level (LOAEL) at an exposure ~12 times 
higher than the human exposure at 60 mg/day in a subsequent multiple-ascending dose (MAD) 
trial. 
• 
Adverse events at high doses in both rats and dogs that were consistent with known adverse 
effects of other BTK inhibitors and/or considered mild. 
• 
Variable effects on pregnancy and embryos. 
2.2.4.2 Phase 1 clinical studies 
Seven Phase 1 clinical studies had been completed as of September 11, 2022. The first used an oral solution 
and was comprised of both single-ascending dose (SAD; N=30; doses ranging from 5–120 mg) and MAD 
(N=40; doses ranging from 7.5–90 mg) components. A second used a 15-mg pill formulation that was 
later adopted for the first Phase 2 study. A third was performed in healthy East Asian men (N=6; doses 
ranging from 7.5–60 mg). Findings are summarized on pp. 17–23 of the IB, with key points as follows: 
• 
Extensive metabolism of the parent drug, with primary excretion in feces. 
• 
Two metabolites (M2 and M5/M5a) with activity against BTK. 
• 
Similar bioavailability of the Phase 3 tablet compared to the Phase 2b product. 
• 
“A positive food effect was observed on tolebrutinib and M2 pharmacokinetics (PK) in moderate- 
and high-fat conditions with both tablets…” 
• 
“After repeated doses of up to 240 mg under fed conditions (moderate fat), Cmax and AUClast values 
for tolebrutinib and M2 increased in proportion to dose, with no major deviation from dose pro-
portionality. Overall, tolebrutinib exhibited linear PK, according to dose and time.” 
• 
At 2 hours, CSF-to-total plasma ratio of ~0.15, and CSF-to-free plasma ratio of ~2.25. 
• 
“The most commonly reported AEs were mild diarrhea and headache… no clinically significant 
drug-related changes in vital signs, electrocardiography (ECG) parameters, or laboratory val-
ues…” except for a reversible ~25% decrease in platelet count in a single participant in the 60-
mg MAD cohort whose platelet count was 145 x 109/L at baseline (slightly below the lower 
limits of normal). 
• 
Predicted moderate PK interactions with CYP3A4 and CYP2C8 inhibitors and inducers, and 
~50% reduction in tolebrutinib exposure when administered with gastric-acid reducing agents. 
• 
Similar pharmacokinetics and safety results in East Asian men as in Western participants. 
TDR16862 is a randomized, double blind, placebo-controlled study of the tolerability and pharmacokinet-
ics of ascending 14-day repeated oral dose of tolebrutinib in healthy adult participants. Nine participants 
received 120 mg daily for 14 days. There were no serious adverse events or significant safety concerns at 
this dose, and no indication that drug-drug interactions should be modified relative to recommendations 
for 60 mg/day dosing. 
2.2.4.3 Phase 2 clinical study 
DRI15928 (NCT03889639) was a multicenter Phase 2b study to test the efficacy of tolebrutinib on reduc-
ing gadolinium-enhancing MRI lesions in relapsing MS. The design was double-blind, randomized, and 
placebo-controlled, with 4 dose levels (5, 15, 30, and 60 mg/day) of tolebrutinib for 12 weeks, which were 
either followed (Cohort 1) or preceded (Cohort 2) by 4 weeks of placebo. The study enrolled 130 partici-
pants ages 18–55 who had 1 relapse in the prior year, 2 or more relapses in the prior 2 years, or at least 1 
gadolinium-enhancing MRI lesion in the prior 6 months. 
As published,32 and according to the IB: “The study met its primary objective, demonstrating a dose re-
sponse relationship for tolebrutinib as evidenced by a reduction in the number of new active Gd-enhancing 
T1 hyperintense brain lesions detected by brain MRI after 12 weeks of treatment, with a statistically sig-
nificant difference in the tolebrutinib 60 mg group as compared to placebo (relative risk [RR] 85.02%; 

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[95% CI: 28.02%, 96.88%]). Differences in the other tolebrutinib treatment groups were not statistically 
significant as compared to placebo. Consistently, efficacy on disease activity was also demonstrated by 
the reduction in the number of new and enlarging T2 lesions detected by brain MRI after 12 weeks of 60 
mg tolebrutinib treatment (RR 89.34%; [95% CI: 68.39%, 96.41%]), but not so for the 5, 15, and 30 mg 
tolebrutinib doses. However, the data did not show a statistically significant reduction in the total count of 
Gd enhancing T1-hyperintense lesions after 12 weeks of tolebrutinib treatment whatever the tested dose.” 
In the Phase 2b, there were no deaths, and “one treatment-emergent SAE [serious adverse event] was 
reported in a participant in Cohort 1 treated with 60 mg SAR442168. All treatment- emergent AEs reported 
were of mild or moderate intensity except for one severe, treatment-emergent AE reported in the 60 mg 
tolebrutinib group.” 
Note that Dr. Daniel Reich, Principal Investigator of this protocol, was involved in discussions with 
Sanofi-Genzyme around the design and analysis of the Phase 2 trial of tolebrutinib, reported its results at 
the 2020 “virtual” annual meeting of the European Academy of Neurology (May 2020), and was the lead 
author of the primary article.32 These discussions were approved as an official-duty activity in his role as 
Senior Investigator in the NINDS Intramural Research Program, and he has not received any remuneration 
for these activities. Dr. Reich’s travel to one or more scientific meetings to present results from the Phase 
2 study will be sponsored by Sanofi-Genzyme, consistent with NINDS procedures. 
A long-term safety extension study (LTS16004; NCT03996291) is ongoing, in which participants were 
initially maintained on their randomized dose from the Phase 2b and subsequently migrated to the 60 mg 
dose used in the phase 3 clinical studies. Initial results from this study were presented at the 2021 “virtual” 
annual meeting of the European Committee on Treatment and Research in MS (ECTRIMS; October 2021), 
and Dr. Reich was the lead author on the report of MRI data. Further data have been presented at subse-
quent meetings, most recently the 2.5-year data at the 2023 Americas Committee on Treatment and Re-
search in MS (ACTRIMS) Forum. These data indicate continued efficacy of the 60 mg dose against new 
gadolinium-enhancing lesions and general stability of paramagnetic rim lesions in the 20% of participants 
in whom this imaging biomarker could be measured. Note that these measurements were performed on a 
variety of scanners on less sensitive 3T MRI systems, so results at 7T MRI with the advanced sequences 
used in this protocol cannot be fully extrapolated.  
2.2.4.4 Phase 3 clinical studies 
Sanofi-Genzyme is sponsoring four Phase 3 multicenter registrational clinical trials of tolebrutinib, two in 
relapsing-remitting MS (GEMINI 1, NCT04410978; GEMINI 2, NCT04410991) and two in progressive 
MS (HERCULES, NCT04411641; PERSEUS, NCT04458051). Dr. Reich serves on the steering commit-
tee for HERCULES and PERSEUS as part of his official duties as Senior Investigator in the NINDS 
Intramural Research Program. He has not received, and will not receive, any remuneration for these activ-
ities. 
2.2.5 Co-treatment with anti-CD20 monoclonal antibodies 
Since tolebrutinib treatment will be initiated within 6 months of each participant’s most recent infusion of 
anti-CD20 monoclonal antibodies, which are normally given every 6 months and cause B cell depletion 
that persists even longer, there will be a period, lasting approximately 3–6 months, during which where 
both treatments are effectively combined. The effects of anti-CD20 are expected to gradually wane, such 
that by the second half of the 96-week duration of the primary study, participants will for all intents and 
purposes be taking tolebrutinib monotherapy. Samples for B cell counts are collected at various time points 
during this protocol. 
Although no prior studies have examined specific co-treatment of tolebrutinib with anti-CD20 monoclonal 
antibodies, there is substantial published data that co-treatment with first-generation BTK inhibitors (such 
as ibrutinib) and anti-CD20 monoclonal antibodies (in particular, rituximab) is safe. 
• 
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(CLL), 6 cycles of ibrutinib 420 mg plus rituximab 375 mg/m2, followed by continuous ibrutinib, 
13% had grade 3 infections, none had grade 4 or grade 5 infections, and only 1 had grade 4 
neutropenia.33 
• 
A Phase 3 study (NCT01611090) of 578 patients with CLL or small lymphocytic leukemia (SLL) 
treated with a standard-of-care therapy, rituximab together with bendamustine, with the addition 
of ibrutinib 420 mg or placebo. At the 17-month interim analysis, progression- free survival was 
improved in the ibrutinib group (hazard ratio 0.23, p<0.0001), and safety signals were similar in 
both groups.34 
• 
A similar study (NCT02048813) subsequently randomized 529 patients with previously un-
treated CLL or SLL to either the same regimen of ibrutinib plus rituximab followed by ibrutinib 
alone or standard-of-care fludarabine, cyclophosphamide, and rituximab chemoimmunotherapy, 
again showing improved progression-free survival (hazard ratio 0.35, p<0.001) similar overall 
adverse event rate in the two groups, and fewer grade 3 infections in the ibrutinib plus rituximab 
group.35 
• 
Another study (NCT02007044) compared 420 mg of ibrutinib to ibrutinib together with rituxi-
mab in 208 CLL, with no difference in efficacy and similar rates of grade 3/4 treatment-emergent 
adverse events in both groups.36 
• 
Most recently, a Phase 2 study (NCT02689141) enrolled 66 patients with CLL who were treated 
with bendamustine followed by ibrutinib together with ofatumumab, a humanized monoclonal 
anti-CD20 antibody that is also under investigation for treatment of MS; no unexpected safety 
signals were reported in this open-label study.37  
• 
On the basis of NCT02048813, the FDA on April 20, 2020 approved the combination of ibrutinib 
and rituximab for the treatment of CLL or SLL. 
2.2.6 Importance of this study 
Currently, no existing treatment for MS is known to impact chronically inflamed (also known as “chronic 
active,” “slowly expanding,” or “smoldering”) white matter lesions. In these lesions, in which inflamma-
tion may persist for decades, there is substantial destruction of the neuropil, and, as such, these lesions 
have been proposed to be part of the basis for clinical progression.20,38 Activated macrophages/microglia 
are the primary inflammatory cell type in chronic active lesions, and modulation of these cells might 
therefore allow a resetting of wound repair mechanisms, thus preventing ongoing tissue damage and po-
tentially allowing endogenous remyelination. 
Thus, we postulate that tolebrutinib will inhibit the pathogenic activities of macrophages/microglia at the 
edge of chronic active lesions, thereby arresting further tissue damage within these lesions. Based on pub-
lished data (discussed above) that co-treatment with first-generation BTK inhibitors and anti-CD20 mon-
oclonal antibodies is safe, we will enroll patients who have been treated with an FDA-approved, anti-
CD20 therapy for at least 6 months and are within 6 months of their most recent dose. We will also enroll 
a comparison cohort of participants who meet inclusion criteria but choose to stay on anti-CD20 therapy, 
and who are followed at similar time points. Finally, we will restrict the study to patients with clinically 
progressive MS, or stable MS, which reflects the current lack of good treatment options to arrest or reverse 
disability in MS. Data from this study will also provide novel information on safety and tolerability of 
long-term (96 week) dosing of tolebrutinib 120 mg daily*, as previously only 14-day dosing has been 
trialed. Vaccination- and COVID-related treatment gaps in anti-CD20 therapy prior to enrollment are not 
exclusionary. In addition to monitoring the effect of tolebrutinib on chronic active lesions, we will collect 
safety and tolerability measures, as well as pharmacodynamic markers of macrophage/microglial modu-
lation in blood and CSF. 
 
* See Section 6.1.2.5 

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2.2.7 Rationale for outcome measures 
7-tesla MRI. As described in Section 2.2.1, 7T MRI can detect iron deposition within activated macro-
phages/microglia at the edge of chronic active white matter lesions, which are the ultimate target of the 
therapy studied in this protocol. 7T MRI is also highly sensitive to the degree of parenchymal damage 
within lesions, and high-resolution data acquisition allows measurement of lesion size that is more accu-
rate than at lower magnetic field strengths. The availability of 7T MRI therefore makes it possible to assess 
the effects of novel therapies on such lesions. 
Safety and tolerability. Safety and tolerability will be assessed through patient interview and logging of 
adverse events (AE), as well as by lab work and imaging. Since tolebrutinib has not previously been used 
jointly with anti-CD20 antibody therapy in the treatment of MS, and it is not known if this combination 
could unexpectedly exacerbate disease inflammatory activity or predispose to development of opportun-
istic infections, safety monitoring by MRI will be interspersed between the 7T visits, with gradually de-
creasing frequency. 
Blood and CSF biomarkers. We will collect blood and CSF samples for exploratory analysis of other 
potential biomarkers of tolebrutinib’s efficacy. Techniques to be used may include (but are not limited to) 
flow cytometry immunophenotyping, cytokine/protein assessments, and single- cell RNA sequencing. 
Specific molecules to be assessed may include (but are not limited to); IL- 1β, IL-2, IL-6, IL-10, IL-12, 
IL-18, TNF, IFNγ, IP-10/CXCL10, soluble CD27, CHI3L1/YKL-40, neopterin, and neurofilament light 
chain. Lumbar puncture is optional in the anti-CD20-only cohort. 
2.3 
RISK/BENEFIT ASSESSMENT 
2.3.1 Known Potential Risks 
The indented material is quoted from edition 11 of the IB for tolebrutinib: 
The safety profile is characterized based on tolebrutinib nonclinical data, Phase 1 results from 
healthy participants, Phase 2b results from adult participants with RMS, the ongoing Phase 3 stud-
ies in RMS, nr-SPMS, PPMS, and gMG, and from published data of an evobrutinib clinical study 
in the RMS indication.25 It also takes into account 3 approved BTK inhibitors (acalabrutnib, ibru-
tinib, and zanubrutinib) in oncology indications, such as mantle cell lymphoma (MCL) and chronic 
lymphocytic leukemia (CLL)…. However, it is unclear whether the risks identified in patients with 
hematologic malignancies (eg, hemorrhage, infection, cytopenia, and atrial arrhythmia) will be ap-
plicable in the MS or gMG populations given the higher selectivity of tolebrutinib and the differ-
ences between the MS/gMG and oncology populations. 
At the current stage of clinical development, tolebrutinib is considered to have the potential risks 
of bleeding, infections, cytopenia (e.g., thrombocytopenia), atrial arrhythmias (atrial fibrillation 
and atrial flutter) and DILI including severe DILI (risk of liver transplantation or death) as an iden-
tified risk. 
Investigators should adhere to inclusion/exclusion criteria and participant monitoring detailed in 
study protocols to manage these potential risks. 
Data supporting the assessment of these risks as identified and potential risks for tolebrutinib are 
presented below. 
Drug-induced liver injury as an identified risk: 
Tolebrutinib nonclinical: No liver toxicity has been observed at any tested dose in any species. 
Tolebrutinib clinical: 
- 
Phase 1 trials: Overall, no safety signal was observed. In the drug-drug interaction study 
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administered tolebrutinib + pantoprazole which led to permanent treatment discontinua-
tion. This participant had abnormal ALT values at screening and baseline (65 and 45 IU/L, 
respectively [ULN = 41 IU/L]), which rose to 94 IU/L at the end of Period 2 (tolebrutinib 
+ pantoprazole) and peaked below 3 × ULN (117 IU/L: 2.85 × ULN). He had no associated 
symptoms. This Grade 2 AESI was considered related to tolebrutinib and pantoprazole by 
the Investigator and was noted as recovering/resolving without corrective treatment/ther-
apy. He also had an increase in AST <2 × ULN, reported as a Grade 1 AE and an increase 
in blood CPK, reported as a Grade 1 AE. 
- 
Phase 2b trials: One participant in each of the tolebrutinib 30 and 60 mg groups had a 
moderate (not related to the study drug) and mild (related to the study drug) event of ALT 
increased >3 × ULN. In both cases, the liver enzymes elevation was transient, the IMP was 
continued, liver enzymes returned to normal levels, and the participant completed the 
study. The event in the participant receiving 30 mg was assessed as moderate with no con-
comitant symptoms. The event in the participant receiving 60 mg was assessed as mild by 
the Investigator and with concomitant pruritus reported; the participant had ALT levels 
above the ULN (34 IU/L) at screening and randomization (48 and 50 IU/L, respectively), 
and ALT >3 × ULN started during the placebo run-in period (Cohort 2 participant); the 
ALT levels did not increase further when the participant crossed over to the tolebrutinib 60 
mg group and decreased over time while the participant continued on tolebrutinib 60 mg. 
- 
In the unblinded extension trial (LTS16004), 1 participant in the open-label period (tole-
brutinib 60 mg) had an ALT increase >8 × ULN associated with an AST increase >5 × 
ULN and abdominal pain. Tolebrutinib was permanently discontinued, and the liver en-
zymes values returned progressively to normal ranges. Additional investigations were per-
formed to rule out viral and autoimmune causes. Anti-smooth muscle antibody (ASMA) 
was weakly positive; however, the test was not repeated. The other tests were negative or 
showed past infection. This AE was assessed as related to tolebrutinib by the Investigator. 
- 
Phase 3 trials are blinded and ongoing. Drug-induced liver injury is an identified risk in the 
MS population for tolebrutinib: Four probable DILI cases characterized by liver enzyme 
elevations of >3 × ULN accompanied by TBILI >2 × ULN have been identified. The cases 
were detected and managed according to protocol monitoring and increased ALT algorithm 
guidelines. Symptoms and laboratory abnormalities were reversible upon tolebrutinib dis-
continuation. 
- 
Potential confounding factors have been identified in 3 of the 4 cases. 
- 
A late-breaking case of severe DILI which resulted in liver transplantation and death has 
occurred. The IMP was discontinued on Day 43. The participant presented on Day 44 with 
liver transaminase and TBILI elevations with a concurrent increase in ALP and subse-
quently developed elevated INR, eventually leading to liver transplantation on Day 97. The 
disease course was further complicated by renal failure and infectious processes, ultimately 
leading to death on Day 153. Potential confounders include obesity and a positive ASMA 
(low titer); repeat ASMA testing was negative. Of note, the initial liver biopsy revealed an 
underlying inflammatory etiology, and an initial improvement in INR values was observed 
during steroid administration (Days 70 through 96). 
Evobrutinib: In the published data for the Phase 2b study, a few participants with elevations in ALT 
and AST were asymptomatic, the elevations were reversible, and no cases met the criteria of Hy’s 
law for DILI, as defined by the Food and Drug Administration. Most of the discontinuations (12 of 
213 [5.6%]) were due to protocol-mandated withdrawals for elevations in levels of ALT and AST, 
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Zanubrutinib: There is a case report of the first case of severe liver injury due to zanubrutinib, a 
BTK inhibitor that has been recently licensed in refractory mantle cell lymphoma and under as-
sessment in Phase 3 clinical trials for other B-cell malignancies. A participant aged between 18 and 
65 years with a history of relapsed lymphoplasmacytic lymphoma was admitted to hospital with 
new onset jaundice, coluria, and pruritus for 10 days. The participant had been receiving za-
nubrutinib as part of a clinical trial for 30 months. The participant’s blood profile showed a severe 
hepatocellular injury with jaundice (ALT 2474 IU/L and TBILI 141 μmol/L with mild coagulopa-
thy). The participant had an extensive work up including virology, autoimmune, and metabolic 
profiles in addition to abdominal ultrasound with no alternative explanation found for the liver 
injury. Zanubrutinib-induced liver injury was suspected, and causality assessment by the updated 
Roussel Uclaf Causality Assessment Method score showed a probable causal relationship with za-
nubrutinib. The participant’s liver histology was also consistent with DILI. The participant’s liver 
biochemistry improved following cessation of zanubrutinib and normalized after 8 weeks. This 
case raises clinical awareness regarding zanubrutinib-induced liver toxicity and the importance of 
drug withdrawal in the event of liver injury. 
Bleeding (hemorrhage): 
Tolebrutinib nonclinical: Hemorrhage in the eye, pancreas, nasal cavity, and mesenteric lymph 
nodes was observed in rats at ≥2 mg/kg/day for 6 months. Minimal hemorrhage in the retropharyn-
geal lymph nodes, stomach, colon, ileum, testis and/or kidney was frequently associated with pig-
ment consistent with hemosiderin was observed in dogs at ≥1 mg/kg/day for 9 months. The effect 
in dogs was not considered adverse due to the mild severity of findings, and the lack of impact on 
the health and wellbeing of the animals. There were no corresponding effects on erythron parame-
ters or platelet counts in either species. 
Tolebrutinib clinical: 
- 
Phase 1 trials: Two events of vascular access site bruising (1 in the tolebrutinib 60 mg 
group and 1 in the tolebrutinib 90 mg group) and 2 events of petechiae in the tolebrutinib 
60 mg group were reported in the MAD study. No hemorrhagic events were reported in the 
Study PRN2246-002 or in the other completed Phase 1 studies (TDU16117 and 
BEX16018). 
- 
Phase 2b trial: One event of mild petechia in a female participant (at Week 8 in the tole-
brutinib 30 mg group) and 2 events of mild microscopic hematuria in 2 male participants 
(1 event at Week 16 in the tolebrutinib 30 mg group and 1 event on Day 1 in the tolebrutinib 
60 mg group, with occult blood noted in urine) were reported during the treatment period 
in the tolebrutinib Phase 2b DRI15928 trial. The hematology results were clinically insig-
nificant for all 3 participants from the onset of the events. The participant with mild pete-
chia had benign pigmentary lesions noted during screening, and the event was assessed as 
related to the study by the Investigator. Details of the anatomic location and clinical presen-
tation of the 2 skin conditions were unavailable. The 2 events of mild microscopic hema-
turia were assessed as unrelated to the study drug. All 3 events resolved spontaneously. 
- 
Phase 3 trials (ongoing): No pattern of bleeding events has been identified during the MS 
and MG Phase 3 trials. Nine serious total bleeding events of 3399 (0.26%) in the Phase 3 
program were considered unrelated to the IMP by the Investigator. For MS participants' 
non-serious bleeding events, the majority of events were petechiae, ecchymoses, and men-
strual bleeding disorders. For the gMG study, 1 non-serious case of bruising was assessed 
as related to background prednisolone therapy. Importantly, no bleeding event is related to 
decreased liver synthetic function or thrombocytopenia. 
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published data of Phase 2b clinical trial in the RMS indication. 
Acalabrutnib: Serious hemorrhagic events, including fatal events, have occurred in the combined 
safety database of 612 patients with hematologic malignancies treated with acalabrutinib mono-
therapy. Grade 3 or higher bleeding events, including gastrointestinal, intracranial, and epistaxis, 
have been reported in 2% of patients. Overall, bleeding events, including bruising and petechiae of 
any grade, occurred in approximately 50% of patients with hematological malignancies. 
Ibrutinib: Fatal bleeding events have occurred in patients treated with ibrutinib. Grade 3 or higher 
bleeding events (intracranial hemorrhage [including subdural hematoma], gastrointestinal bleeding, 
hematuria, and post procedural hemorrhage) have occurred in 6% of patients, with fatalities occur-
ring in 0.3% of 1124 participants exposed to ibrutinib in clinical trials. Bleeding events of any 
grade, including bruising and petechiae, occurred in 44% of patients treated with ibrutinib. 
Zanubrutinib: Fatal and serious hemorrhagic events have occurred in patients with hematological 
malignancies treated with zanubrutinib monotherapy. Grade 3 or higher hemorrhage including in-
tracranial and gastrointestinal hemorrhage, hematuria and hemothorax have been reported in 3.4% 
of patients treated with zanubrutinib monotherapy. Hemorrhage events of any grade, excluding 
purpura and petechiae, occurred in 35% of patients. 
39The mechanism for the bleeding events in this class of products is not well understood, with a 
potential mechanism being the inhibition of collagen-mediated platelet activation, spreading, and 
aggregation in vitro; however, prolonged bleeding was not observed in a model of bleeding.40 
To mitigate this risk, selection criteria exclude participants with low platelet levels. In addition, 
antiplatelet or anticoagulant therapies are not allowed at inclusion and in concomitant use during 
the studies. Platelet counts will be monitored regularly. Treatment with IMP is to be withheld before 
and after surgery. 
Infections:  
Tolebrutinib is an immunomodulator of B cells and innate immune cells, which could increase the 
risk of infection. 
Tolebrutinib nonclinical: No infection was observed at any tested doses in any species. In a 6-
month toxicity study in rats, TDAR findings of decreased IgG and IgM response to antigen were 
observed at ≥2 mg/kg/day tolebrutinib. 
Tolebrutinib clinical: 
- 
Phase 1 trials: No significant infection occurred. Common cold occurred with no apparent 
relationship to dose in Study PRN2246-001. No significant infections were reported in the 
PRN2246-002 Study. 
- 
Phase 2b trial: No significant infections occurred. The most frequently reported infections 
(≥3 events total) during the tolebrutinib treatment period were upper respiratory tract in-
fection (2 in the tolebrutinib 5 mg group, 2 in the tolebrutinib 15 mg group, 1 in the tole-
brutinib 30 mg group, and 1 in the tolebrutinib 60 mg group), nasopharyngitis (1 in the 
tolebrutinib 5 mg group, 1 in the tolebrutinib 30 mg group, and 3 in the tolebrutinib 60 mg 
group), gastroenteritis (1 in the tolebrutinib 5 mg group and 2 in the tolebrutinib 60 mg 
group), and respiratory tract infection (1 in the tolebrutinib 15 mg group, 1 in the tolebru-
tinib 30 mg group, and 1 in the tolebrutinib 60 mg group). Total infection incidence was 
below 30% without evidence of dose dependence. 
- 
Phase 3 trials (ongoing): No pattern of infection safety events has been identified during 
the ongoing blinded MS and gMG Phase 3 trials. The overall incidence of infection events 
for the tolebrutinib-treated MS population was 14 of estimated 1956 (by randomization 

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ratio, 0.7%). Importantly, 6 of these 14 events (ie, 6 of 1956 [0.3%]) were COVID-19 
related during the pandemic. In comparison, review of blinded infection events reveals 57 
of 3548 (1.6%) with various bacterial, fungal, and viral infections (serious and non-seri-
ous), of which 26 (0.8%) were again COVID-19 related. Therefore, preliminary data do 
not indicate an increased risk of infection or COVID-19 outcomes during the tolebrutinib 
MS development program. Furthermore, no incidence of hepatitis-B-virus (HBV)-reacti-
vation-induced liver injury has been reported. 
Evobrutinib: Nasopharyngitis was reported as the most frequent AE in the Phase 2b study. Some 
cases of upper respiratory and urinary infections were reported. Incidence of all infection was 20% 
to 30% with no evidence of dose dependence. 
Ibrutinib: Fatal infections have occurred. Grade 3 or greater infections occurred in 14% to 29% of 
patients. Progressive multifocal leukoencephalopathy (PML) and Pneumocystis jiroveci pneumo-
nia have occurred. 
Acalabrutnib: Grade 3 or higher infections occurred in 18% of patients, most frequently reported 
event was pneumonia. Hepatitis B virus reactivation and PML have occurred. 
Zanubrutinib: Fatal and serious infections (including bacterial, viral, or fungal) and opportunistic 
infections have occurred in patients with hematological malignancies treated with zanubrutinib 
monotherapy. Grade 3 or higher infections occurred in 27% of patients, most commonly pneumo-
nia. Infections due to HBV reactivation have occurred. 
Collection of AEs throughout the study is considered adequate to detect infections. Participants 
will be informed of this risk while taking informed consent and will be instructed to contact Inves-
tigators immediately in case of symptoms. 
Cytopenia including thrombocytopenia: 
Tolebrutinib nonclinical: No cytopenia has been observed at any tested dose in any species. 
Tolebrutinib clinical: 
- 
Phase 1 trials: One participant in the 60 mg Phase 1 MAD cohort of Study PRN2246-001 
developed decrease platelet counts that led to the unblinding of the treatment. The partici-
pant’s platelet count was decreased from 145 × 109/L at baseline (reference range: 150 to 
450 × 109/L) to 122 × 109/L at Day 7 after dosing, and subsequently decreased to 105 × 
109/L at Day 9. The participant did not receive the study treatment at Day 10, and platelet 
level was 118 × 109/L at Day 10. The event of decreased platelet count was resolved, and 
platelet levels recovered 7 days after the last dose with platelet counts of 142 × 109/L. No 
bleeding AEs were reported in this participant. Other AEs reported in this participant in-
cluded bloating, headache, abrasion of abdomen, abdominal bloating, and redness on sites 
of ECG electrodes. No significant cytopenias, including thrombocytopenia and neutro-
penia were reported in the PRN2246-002 Study. 
- 
Phase 2b trial: No significant cytopenia including thrombocytopenia and neutropenia were 
reported or detected through lab results review. 
- 
Phase 3 trials (ongoing): No evidence of significant cytopenias (including thrombocytope-
nia, neutropenia, and lymphopenia) has been identified during the MS and gMG Phase 3 
trials. Mitigation includes clinical hematology laboratory assessments the thrombocytope-
nia algorithm in each protocol. 
Evobrutinib: Low lymphocyte count was reported in 1 participant from the 75 mg twice daily group 
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Ibrutinib: Grade 3 or 4 cytopenias occurred including neutropenia (13% to 29%), thrombocytopenia 
(5% to 17%), anemia (0% to 13%). 
Acalabrutinib: Grade 3 or 4 cytopenias occurred, including neutropenia (23%), anemia (11%) and 
thrombocytopenia (8%) based on lab measurements. 
Zanubrutinib: Grade 3 or 4 cytopenias, including neutropenia (26%), thrombocytopenia (11%) and 
anemia (8%) based on laboratory measurements, developed in patients treated with zanubrutinib 
monotherapy. Grade 4 neutropenia occurred in 13% of patients, and Grade 4 thrombocytopenia 
occurred in 3.6% of patients. 
41Regular hematology monitoring will be performed during the study to mitigate cytopenia risks. 
Atrial arrhythmia (atrial fibrillation and atrial flutter):  
Tolebrutinib nonclinical: No clinically relevant signals. Tolebrutinib inhibited hERG potassium 
channel tail currents with an IC50 of 9.1 µM. For context, the Cmax for tolebrutinib at the highest 
clinical dose tested to date (120 mg) was 71 nM. No effect on the cardiovascular system was ob-
served in a telemetered study in conscious dogs. 
Tolebrutinib clinical:  
- 
Phase 1 and Phase 2b trials: No clinically significant cardiac arrhythmias were observed. 
PCSAs [potentially clinically significant abnormalities] related to ECGs (eg, heart rate <50 
beats/min, heart rate >90 beats/min, heart rate >100 beats/min, PR >200 msec, QRS >110 
msec, QTc Bazett >450 msec, QTc Fridericia >450 msec) were reported in a small number 
of participants. These PCSAs were isolated occurrences and no dose relationship was ob-
served. 
- 
Phase 3 trials (ongoing): No pattern of atrial arrythmia safety events has been seen in the 
MS and gMG Phase 3 trials. To date, only 1 blinded case with atrial arrythmia has been 
identified at Day 5 post-seizure…. A participant aged between 18 and 64 years with history 
of RMS and seizure disorder presented on Day 5 to an emergency room with dizziness, 
sudden seizure, and atrial flutter (CTCAE Grade 2) noted on ECG. The participant was 
prescribed diltiazem for atrial flutter event. The participant returned on Day 18 in normal 
sinus rhythm. The Investigator deemed the atrial flutter event as nonserious, an AESI, and 
not related to IMP. The IMP was continued without interruption. 
Evobrutinib: In the Phase 2b study, no cardiac arrhythmia was observed. 
Ibrutinib: In a pooled data review,42 atrial fibrillation was the most common AE that led to discon-
tinuation. In pivotal trials atrial fibrillation was observed in 5% to 7% of ibrutinib patients, com-
pared <1% to 2% of the comparator groups. Meta-analysis showed that the atrial fibrillation rate 
was 3.3/100 person-year over a median follow up of 26 months (control: 84/100 person-years). 
Prevalence over 10-year retrospective data was 6.1%. 
Acalabrutinib: Atrial fibrillation/flutter of any grade occurred in 3% of patients, and Grade 3 atrial 
fibrillation/flutter occurred in 1% of patients. 
Zanubrutinib: Atrial fibrillation and atrial flutter were reported in 3.2% of patients treated with 
zanubrutinib monotherapy. Patients with cardiac risk factors, hypertension and acute infections 
may be at increased risk. Grade 3 or higher events were reported in 1.1% of patients treated with 
zanubrutinib monotherapy. 
The mechanism of atrial arrhythmia is poorly understood. No clinically significant cardiac arrhyth-
mias have been observed to date with tolebrutinib. Monitoring with regular ECGs is scheduled. 
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with abnormal ECG values that are judged of clinical significance for participation in this study. 
 
2525With respect to drug interactions, the following material is quoted from edition 11 of the IB: 
Effects of interacting drugs on tolebrutinib for CYP inhibitors/inducers 
Based on the PK results from the drug-drug interaction studies INT16726 and INT16385 with 
tolebrutinib and M2 data and based on their corresponding PK exposure in the MAD study 
TDR16862 at up to 240 mg under fed conditions with corresponding satisfactory safety/tolera-
bility data, concomitant use of tolebrutinib at 60 mg daily under fed conditions with drugs is 
updated as follows: 
• 
All CYP3A inhibitors are allowed, because the interaction of the potent CYP3A4 inhibitor 
itraconazole produced a mild interaction on tolebrutinib and its active metabolite M2, and 
the exposures of tolebrutinib and M2 after co-administration of the 60 mg Phase 3 tablet 
under fed conditions with itraconazole remained below their exposures at 240 mg once 
daily, a safe and well tolerated dose. 
• 
Coadministered potent CYP2C8 inhibitors should be avoided in order that tolebrutinib 
exposures remain below their exposures at 240 mg once daily. Moderate and weak 
CYP2C8 inhibitors are allowed. 
• 
Potent and moderate CYP3A inducers (being also CYP2C8 inducers) should be 
avoided, as they may decrease the combined exposures of active moieties tolebrutinib 
and M2 by more than 50%. 
Recommendations for comedication with gastric pH modifiers (proton pump inhibitors, H2-
receptor blockers, and antacids) 
Based on the drug interaction of pantoprazole (40 mg twice daily) toward tolebrutinib (60 mg under 
fed conditions) showing no effect on AUC, with a mild decrease on Cmax (34% to 39%), coadmin-
istration of pump proton inhibitors, H2-receptor blockers, and antacids are allowed. 
The mild decrease in Cmax is considered to be not clinically relevant. The cumulative AUC up to 
tmax when tolebrutinib was co-administered with a proton pump inhibitor was similar to that of 
tolebrutinib alone, as the ratios of cumulated AUC up to tmax were close to 1 for tolebrutinib and 
M2. 
Effects of tolebrutinib on interacting drugs 
The risks of interaction of tolebrutinib as a perpetrator by CYP inhibition and induction and trans-
porter inhibition were assessed for tolebrutinib and its main metabolites (M2, M5/M5a, M8, M10, 
and M18, for which exposure of the metabolites represented >100% of the exposure of the parent 
compound. The risk of interaction was assessed using a static approach and PBPK modeling fol-
lowing the FDA Guidance on in vitro Drug Interaction Studies - Cytochrome P450 Enzyme- and 
Transporter-Mediated Drug Interactions (January 2020)/(EMA Guideline on the investigation of 
drug interactions, 2012). The drug-drug interaction risk assessment of tolebrutinib, taking into ac-
count abundant metabolites compared to parent drug has been completed, and no PK interactions 
toward other drugs are predicted in vivo. 
 
With respect to carcinogenesis, the following material is quoted from edition 11 of the IB: 
Carcinogenicity studies have not been conducted to date. 

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Tolebrutinib was negative for genotoxic potential in the Ames test and the in vivo micronucleus 
test in rats. Increased structural aberrations were observed in the in vitro chromosome aberration 
test at concentrations that produced substantial cytotoxicity. 
Completed developmental and reproductive toxicity studies provide support for use of tolebrutinib 
at doses up to 60 mg. There were no effects on fertility or early reproductive performance in rats. 
tolebrutinib exposure ratios at the embryo-fetal NOAEL were 74 times higher in rats and 193 times 
higher in rabbits compared to the human exposure at 60 mg in DRI15928 (49.8 ng.h/mL). 
 
With respect to overdose, the following material is quoted from edition 11 of the IB: 
No symptomatic overdose was reported in the completed or ongoing clinical trials as of the data 
cutoff date. 
 
Although dual therapy with earlier BTK inhibitors and anti-CD20 antibodies has been studied in oncology, 
there are no prior reports of this strategy in MS. Because anti-CD20 therapy depletes B cells in the periph-
ery, the BTK inhibition in this study will mostly affect myeloid cells, at least initially after the treatment 
switch. The potential risk from the dual therapy in MS is unknown. 
There is unknown risk of chronic dosing with tolebrutinib 120 mg/day, as this dose has only been given 
previously for up to 14 days. The lack of serious adverse events for 14-day dosing and the ongoing safety 
data from longer-term dosing at 60 mg, together with monitoring every 12 weeks in this protocol, mitigate 
this risk. 
Participants who elect not to participate in the study will receive ongoing routine care for their MS. They 
can continue to be followed in NIH natural history protocols and may be eligible for other clinical trials 
at NIH or elsewhere. 
2.3.2 Known Potential Benefits 
Participants (i.e., adults who become unable to consent and participants who receive tolebrutinib) may 
benefit from participation if tolebrutinib at 60 or 120 mg daily is able to decrease or resolve chronic in-
flammation in MS, as such inflammation may play an important role in disease progression. They may 
also benefit through protection against development of new lesions, as suggested in the Phase IIb study in 
relapsing MS and its long-term extension. Participants in the anti-CD20-only arm may benefit from closer 
disease monitoring and surveillance. Although the number of participants is small, and clinical measures 
of MS progression are highly variable, MS relapse and disability scale data will be collected and analyzed. 
If we learn information during this study that may be important for a specific participant’s health, we will 
share that information with the participant and possibly with the participant’s outside medical provider(s). 
Finally, data from this study may be useful for designing longer-term and larger studies of higher-dose 
tolebrutinib in MS. 
2.3.3 Assessment of Potential Risks and Benefits 
Risks to participants, including those that derive from the novel dual treatment with anti-CD20 antibody 
therapy and BTK inhibition, are mitigated by strict adherence to the inclusion/exclusion criteria, frequent 
monitoring using MRI scans, laboratory work, and ECGs, as well as the DILI monitoring plan and hepa-
tology assessment committee (Appendix 2). With these measures in place, the safety profile of tolebrutinib 
in prior clinical studies is promising. Therefore, since there are no approved treatments for control of 
chronic neuroinflammation in MS, nor are there studies of the effect of BTK inhibition on chronic active 
MS lesions assessed using 7T MRI, the potential benefits outweigh these risks. 
 
 

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3 
OBJECTIVES AND ENDPOINTS 
 
OBJECTIVES 
ENDPOINTS 
JUSTIFICATION FOR 
ENDPOINTS 
Primary 
 
 
To evaluate the effects of 48 
weeks of tolebrutinib 60 mg 
treatment on the paramag-
netic rim of chronically in-
flamed white matter lesions, 
as seen on 7-tesla MRI. 
Per-participant proportion of lesions 
in which the paramagnetic rim has 
disappeared at the end of 48 weeks of 
tolebrutinib 60 mg treatment. 
Paramagnetic rims indi-
cate the presence of in-
flammation and ongoing 
demyelination and axonal 
transection at the lesion 
edge. We have never ob-
served complete disap-
pearance of a chronic rim 
over the course of 
months, and the lesions 
under study will have 
been present for at least 6 
months. 
Secondary 
 
 
To assess safety and tolera-
bility of 96 weeks of tole-
brutinib 60 mg (initial co-
hort), or 48 weeks of treat-
ment with tolebrutinib 60 
mg and 96 weeks of treat-
ment with tolebrutinib 120 
mg (Cohort A), all follow-
ing anti-CD20 antibody 
therapy. 
Tabulation of adverse events. 
There are no prior data 
regarding the specific 
combination of tolebru-
tinib and anti-CD20 anti-
bodies, or of BTK inhibi-
tors and anti-CD20 anti-
bodies in MS. 
To assess the possible repair 
of chronically inflamed white 
matter lesions in which in-
flammation at the lesion edge 
has been modulated by tole-
brutinib. 
Changes in T1 relaxation time within 
paramagnetic rim lesions at the end of 
96 weeks of tolebrutinib 120 mg, rela-
tive to non-rim lesions. The analysis of 
T1 relaxation time changes will be per-
formed by analysis of variance or 
mixed-effects models in study complet-
ers. A threshold p-value of 0.025 will 
be taken as a significant change. 
A reduction of the T1 
relaxation time would be 
compatible with lesion 
repair. 
To assess the possible repair 
of chronically inflamed white 
matter lesions in which in-
flammation at the lesion edge 
has been modulated by tole-
brutinib. 
Changes in size of paramagnetic rim 
lesions at the end of 96 weeks, relative 
to non-rim lesions. The analysis will 
be performed by analysis of variance 
or mixed-effects models in study com-
pleters. A threshold p-value of 0.025 
will be taken as a significant change. 
A reduction in lesion 
size could indicate le-
sion repair. 
Tertiary/Exploratory 
 
 

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To assess the time course of 
an effect of tolebrutinib on 
the paramagnetic rims of 
chronically inflamed white 
matter lesions. 
Proportion of paramagnetic rim le-
sions in which the rim has diminished 
or disappeared at any time point, as-
sessed by analysis of variance or 
mixed-effects models, which naturally 
handle missing data. 
The time course of any 
effect of tolebrutinib on 
chronic neuroinflam-
mation is unknown. 
To obtain clinical data rele-
vant to the efficacy of tole-
brutinib. 
Expanded Disability Status Scale 
(EDSS), 9-hole peg test (9HPT), 25- 
foot timed walk (25FTW), Scripps 
Neurological Rating Scale (SNRS), 
and symbol digit modalities test 
(SDMT), at baseline and every 24 
weeks thereafter. 
These are standard dis-
ability scales that are 
used in the assessment 
of clinical progression 
in MS. 
To obtain additional imaging 
data relevant to the efficacy 
of tolebrutinib. 
Characteristics, including persistence, 
of paramagnetic rims at all time points 
(qualitative). Additional MRI 
measures to be determined. These 
analyses will be performed in NIH 
labs or through collaboration, either 
intramural or extramural. 
To assess imaging cor-
relates of reduced 
chronic neuroinflam-
mation and/or tissue re-
pair. 
To obtain laboratory data rel-
evant to the safety and effi-
cacy of tolebrutinib. 
Immune cell populations (e.g., macro-
phages, lymphocytes, and subtypes 
thereof), cytokines (e.g., IL- 1ß, IL-6), 
and protein and other biomarkers of 
neuroinflammation and neurodegener-
ation (e.g., neurofilament light chain, 
chitinase-3-like-1). Additional assays 
may also be developed and performed, 
such as the rate of repopulation of 
CD19+ cells. These analyses will be 
performed in NIH labs or through col-
laboration, either intramural or extra-
mural. 
To assess laboratory 
correlates of reduced 
chronic neuroinflam-
mation and/or tissue re-
pair. 
4 
STUDY DESIGN 
4.1 
OVERALL DESIGN 
This is a single-site, Phase 2, two-arm, baseline-to-treatment trial to test the hypothesis that 48 weeks of 
treatment with tolebrutinib 60 mg, and a subgroup of patients escalated to 120mg, on an investigational, 
orally available, brain-penetrant, BTK inhibitor, can modulate an imaging marker (the “paramagnetic 
rim”) associated with chronically inflamed (“chronic active” or “smoldering”) white matter lesions in MS 
patients under stable treatment with anti-CD20 antibodies. The trial is open-label, and bias will be mini-
mized by analysis of the primary and MRI-based secondary outcomes blinded to time point. No interim 
analysis, stratification, or sub-study is planned due to the small size of this study and the value of obtaining 
a complete dataset for exploratory analysis and guiding of future therapeutic development and clinical trial 
design. A comparison cohort of individuals who meet enrollment criteria (other than tolebrutinib contra-
indications) but choose not to take tolebrutinib will be enrolled and followed. Enrollment of the first 2 
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4.2 
SCIENTIFIC RATIONALE FOR STUDY DESIGN 
Natural history data (both published and unpublished) indicate that in the absence of treatment, including 
treatment with anti-CD20 antibodies, paramagnetic rims are stable over periods substantially longer than 
the 96-week treatment duration in this study. Indeed, in unpublished work from the NIH, only 1 out of 29 
individuals experienced subtle changes in the paramagnetic rim over the medium term (a period of ~5 
years), meaning that we expect no untreated participants to experience changes in the shorter time period 
of observation in this study. The baseline-to- treatment design of this study, with a primary MRI outcome, 
is therefore justified. 
Disease Community Engagement: 
Investigators have ongoing relationships and participate actively with community and patient advocacy 
groups focused on multiple sclerosis, most notably the National Multiple Sclerosis Society. Investigators 
routinely present knowledge and data at support groups, conferences, and patient educational events. Sum-
mary results from this study may be communicated through presentations at meetings, publications in 
peer-reviewed journals and/or if appropriate, press releases. Publications may be shared and discussed 
with participants as requested. 
Patients who have participated in other Neuroimmunology Clinic protocols are actively engaged in our 
research efforts and provide ongoing feedback about the design of our research protocols, including pro-
cedures that may be especially taxing or impede participation particularly in the setting of high disability. 
Patients are the driving force to clinical studies not only with their participation but also with their active 
voice to improve their quality of life in multiple sclerosis. Research subject perspectives were included in 
defining clinical outcome measures through direct meetings with patients, caregivers, and support group 
representatives. As we do not expect to modulate clinical outcomes, we did not formally consult with 
organized patient groups about the design of this short study. 
4.3 
JUSTIFICATION FOR DOSE 
The following is quoted from the protocol of Sanofi-Genzyme’s protocol DRI15928, “A Phase 2b dose-
finding study for SAR442168, a Bruton's tyrosine kinase inhibitor, in participants with relapsing multiple 
sclerosis” (NCT03889639): 
First, allometric modeling intended to translate BTK occupancy by SAR442168 in preclinical animals 
(mouse, rat, and dog) predicts an optimal dose range between 1 and 100 mg once daily in humans. Second, 
Phase 1 multiple ascending- -dose measurements of BTK occupancy in human peripheral blood mononu-
clear cells (PBMCs) show an asymptotic approach to saturation of the receptor by SAR442168 at the 7.5 
mg once daily dose with a more rapid approach to saturation at higher doses. Finally, measurements of 
absolute CD19+ B cell counts show a dose- dependent increase (observed maximally at Day 4) of up to 
80% relative to baseline. The BTK- induced increase in circulating B cells is predicted from the literature, 
as BTK inhibition alters expression of cell surface adhesion molecules leading to egress from lymph 
nodes.43 The dose-response relationship for this effect is maximal at approximately 30 mg once daily. 
However, published results of NCT03889639 suggest that of the doses tested, peak efficacy in relapsing 
MS, with no increase in adverse reactions, was instead achieved at 60 mg once daily for 12 weeks, which 
was the highest dose tested.32 This prompted choice of the 60-mg dose for the ongoing multicenter Phase 
3 trials of tolebrutinib (to be taken with food due to a moderate food effect in the Phase 1 studies), but also 
led Sanofi to test higher doses in TDR16862, a randomized, double blind, placebo-controlled study of the 
tolerability and pharmacokinetics of ascending 14-day repeated oral dose of tolebrutinib in healthy adult 
participants. Nine participants received 120 mg daily for 14 days. There were no serious adverse events 
or significant safety concerns at this dose, and no indication that drug-drug interactions should be modified 
relative to recommendations for 60 mg/day dosing. Additionally, initial results from the long-term safety 
study of the Phase 2b cohort, LTS16004, indicate general stability of paramagnetic rim lesions in the 20% 
of participants in whom this imaging biomarker could be measured. Note that these measurements were 

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performed on a variety of scanners on less sensitive 3T MRI systems, so results at 7T MRI with the ad-
vanced sequences used in this protocol cannot be fully extrapolated. The lack of a strong efficacy signal 
even in the preliminary analysis of LTS16004, along with good tolerability of the 120-mg dose in 
TDR16862, justified escalation of the treatment dose for participants in this protocol. 
Since no drug has yet been shown to resolve chronic active white matter lesions, and since disappearance 
of paramagnetic rim lesions has not previously been used as an outcome measure in clinical trials, the 
timing of the study visits at which efficacy outcomes are measured is somewhat arbitrary. As mentioned 
above, chronic active lesions are established on the order of 3–6 months following initial demyelination, 
so that 48 weeks at the target dose is a reasonable time point at which to measure the primary outcome. 
Additional measurements will be taken at 24, 72, 96, 120, and 144 weeks (the last two in Cohort A) to 
determine the time course of rim disappearance and any associated promotion of lesion repair. Following 
the initial 96 weeks of tolebrutinib 60 or 120 mg therapy, participants will be eligible to continue therapy, 
with monitoring visits every 24 weeks (or more frequently if clinically necessary), either until tolebrutinib 
is marketed or until its development is halted. 
5 
STUDY POPULATION 
5.1 
INCLUSION CRITERIA 
In order to be eligible to participate in this study, an individual must meet all of the following criteria: 
5.1.1 Tolebrutinib Cohorts Inclusion Criteria 
1. Able to provide informed consent 
2. Willingness to comply with all study procedures and availability for the duration of the study 
3. Male or female, aged ≥18 
4. Diagnosed with multiple sclerosis according to the 2017 revision of the McDonald diagnostic 
criteria,4 with no new lesion formation by comparison of baseline MRI scan with a historical 
MRI scan at least 6 months prior 
5. On anti-CD20 antibody treatment for at least 6 months, with the most recent dose at most 6 
months prior to enrollment. 
6. Willing to forego further anti-CD20 antibody treatment for the duration of the study 
7. Fully vaccinated against SARS-CoV-2 by Day 0. At the time of this writing, fully vaccinated is 
defined as: 
• 
Two weeks out from the second dose of a two-dose vaccine series (Moderna, Pfizer-Bi-
oNTech); or 
• 
Two weeks out from a single-dose vaccine (Johnson & Johnson/Janssen) 
Note: Should guidelines change, we will amend these inclusion criteria accordingly.  
8. Has a prior 7-tesla MRI scan, no more than 1 year prior to enrollment, demonstrating at least one 
white matter lesion with a paramagnetic rim44 
9. For females of reproductive potential: agrees to use highly effective contraception for at least 1 
month prior to dosing and to use such a method during study participation and for an additional 
12 weeks after the end of tolebrutinib administration 
10. For males of reproductive potential: agrees to use condoms or other methods to ensure effective 
contraception with partner; agrees not to donate sperm from the inclusion up to 12 weeks after 
the last dose 
11. QuantiFERON-TB Gold negative; skin testing (e.g., tuberculin skin test) will be allowed if blood 
testing is not available or the blood test result is indeterminate 
12. Agrees to adhere to Lifestyle Considerations (see section 5.4) throughout study duration 
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5.1.2 Control Cohort Inclusion Criteria 
1. Able to provide informed consent 
2. Willingness to comply with all study procedures and availability for the duration of the study 
3. Male or female, aged ≥18 
4. Diagnosed with multiple sclerosis according to the 2017 revision of the McDonald diagnostic 
criteria,4 with no new lesion formation by comparison of baseline MRI scan with a historical 
MRI scan at least 6 months prior 
5. On anti-CD20 antibody treatment for at least 6 months, with the most recent dose at most 6 
months prior to enrollment. (Participants in this cohort should remain on their baseline anti-
CD20 treatment at least through week 48.) 
6. Has a prior 7-tesla MRI scan, no more than 1 year prior to enrollment, demonstrating at least 
one white matter lesion with a paramagnetic rim44 
7. For females of reproductive potential: agrees to use highly effective contraception during study 
participation 
8. Agrees not to participate in any other interventional study while participating in this pro-
tocol 
5.2 
EXCLUSION CRITERIA 
An individual who meets any of the following criteria will be excluded from participation in this study: 
5.2.1 Tolebrutinib Cohorts Exclusion Criteria 
1. Pregnancy or lactation 
2. MS relapse in the 6 months prior to dosing 
3. Febrile illness within 4 weeks prior to dosing, or persistent chronic or active infection requiring 
treatment with systemic antibiotics, antivirals, or antifungals. 
4. Treatment with another investigational drug or other investigational intervention within 3 
months prior to baseline. 
5. Contraindications for 7-tesla MRI 
6. Presence of screening laboratory or ECG values outside normal limits that are considered in the 
PI or MAI’s judgment to be clinically significant, including but not limited to: 
a. Presence of liver injury defined as underlying hepatobiliary disease or screening alanine 
aminotransferase (ALT) more than 1.5 times the upper limit of normal (ULN) 
b. At screening, positive for hepatitis B surface antigen and/or hepatitis B core antibody 
and/or positive for hepatitis C antibody 
c. Any of the following: 
i. Bleeding disorder or known platelet dysfunction at any time prior to the first 
screening visit 
ii. Platelet count less than 150,000/μL at the screening visit 
d. Lymphocyte count less than 1000 cells/dL at the screening visit 
7. Is HIV-positive 
8. Has received any live (attenuated) vaccine (including but not limited to varicella zoster, oral 
polio, and nasal influenza) within 2 months before dosing 
9. Has received any of the following medications/treatments within the specified time frame before 
baseline assessment: 
Medication 
Exclusionary if used/used within re-
quired wash-out period 
Systemic corticosteroids, adrenocorticotropic hor-
mone (other than used for premedication) 
1 month prior to baseline MRI scan 
Dimethyl fumarate 
6 months prior to dosing 
Intravenous immunoglobulin, fingolimod, 
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natalizumab 
Teriflunomide 
2 years prior to dosing or 1 month prior 
to dosing if participant undergoes an 
accelerated elimination procedure and 
has documented teriflunomide plasma 
level below 0.02 mg/L before dosing 
Mildly to moderately immunosuppressive/chemo-
therapeutic medications such azathioprine and 
methotrexate 
6 months prior to dosing 
Highly immunosuppressive/chemotherapeutic 
medications: mitoxantrone up to 120 mg/m2 body 
surface area, cyclophosphamide, cladribine 
2 years prior to dosing 
Alemtuzumab 
4 years prior to dosing 
Lymphoid irradiation, bone marrow transplanta-
tion, mitoxantrone (with evidence of cardiotoxi-
city following treatment, or cumulative lifetime 
dose >120 mg/m2), other strongly immunosup-
pressive treatments with very long-lasting effects 
Any time 
Any BTK inhibitor 
Any time 
10. Is receiving potent and moderate inducers and inhibitors of cytochrome P450 3A (CYP3A) or 
potent inhibitors of CYP2C8 hepatic enzymes as listed in Appendix 1. 
11. Is receiving anticoagulant/antiplatelet therapies, including: 
a. Acetylsalicylic acid (aspirin); half-life elimination: Parent drug: Plasma concentration: 
15 to 20 minutes; Salicylates (dose dependent): 3 hours at lower doses (300 to 600 mg), 
5 to 6 hours (after 1 g), 10 hours with higher doses 
b. Antiplatelet drugs (eg, clopidogrel); half-life: 6 hours 
c. Warfarin (vitamin K antagonist); half-life: 20-60 hours 
d. Heparin, including low molecular weight heparin (antithrombin agents); half-life: 60-90 
minutes 
e. Dabigatran (direct thrombin inhibitor); half-life:12-17 hours 
f. Apixaban (IV half-life: approximately 5 hours, oral half-life: approximately 12 hours), 
edoxaban (half-life: 10-14 hours), rivaroxaban (half-life: 5-9 or 11-13 hours in younger 
or elderly individuals, respectively) (direct factor Xa inhibitors) 
Note: All above drugs need to be stopped at least 5 half-lives before study drug administration except for 
aspirin, which needs to be stopped at least 8 days before. 
 
12. Has a history or presence of significant other concomitant illness that, according to the PI or 
MAI’s judgment, would adversely affect participation in this study; examples include but are not 
limited to clinically significant cardiovascular, renal, hepatic, or metabolic disease. 
• 
Acute liver disease, cirrhosis, chronic liver disease (unless considered stable for >6 months) 
• 
Has untreated hepatitis C 
• 
Has chronic hepatitis B unless stable on oral suppression and/or followed by a local hepatol-
ogist to monitor for reactivation 
• 
Has active alcohol use disorder 
• 
Has an alcohol intake greater than 2 drink per day for men, and greater than 1 drink per day 
for women (1 drink = approximately 14 grams of alcohol = 350 ml beer = 140 mL wine = 40 
mL of spirits) 
• 
Has aspartate transaminase (AST) or alanine transaminase (ALT) levels greater than 1.5x 

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ULN 
• 
Has a total bilirubin level greater than 1.5x ULN unless due to Gilbert’s or non-liver related 
disorder 
• 
Has an alkaline phosphatase level greater than 2x ULN unless caused by non-liver related 
disorder or explained by a stable chronic liver disorder  
• 
At baseline, elevated transferrin saturation (>50% in males and >40% in females) and/or 
with elevated ferritin levels >500 μg/L. 
13. Unwilling to allow coded samples to be processed offsite 
14. Unwilling to have coded samples and/or data saved or used in other studies. 
5.2.2 Control Cohort Exclusion Criteria 
1. Pregnancy or lactation 
2. MS relapse in the 6 months prior to baseline 
3. Treatment with another investigational drug or other investigational intervention within 3 
months prior to baseline 
4. Contraindications for 7-tesla MRI 
5. Has received any of the following medications/treatments within the specified time frame before 
baseline assessment: 
Medication 
Exclusionary if used/used within re-
quired wash-out period 
Systemic corticosteroids, adrenocorticotropic hor-
mone (other than used for premedication) 
1 month prior to baseline MRI scan 
Dimethyl fumarate 
6 months prior to dosing 
Intravenous immunoglobulin, fingolimod, natali-
zumab 
6 months prior to dosing 
Teriflunomide 
2 years prior to dosing or 1 month prior 
to dosing if participant undergoes an 
accelerated elimination procedure and 
has documented teriflunomide plasma 
level below 0.02 mg/L before dosing 
Mildly to moderately immunosuppressive/chemo-
therapeutic medications such azathioprine and 
methotrexate 
6 months prior to dosing 
Highly immunosuppressive/chemotherapeutic 
medications: mitoxantrone up to 120 mg/m2 body 
surface area, cyclophosphamide, cladribine 
2 years prior to dosing 
Alemtuzumab 
4 years prior to dosing 
Lymphoid irradiation, bone marrow transplanta-
tion, mitoxantrone (with evidence of cardiotoxi-
city following treatment, or cumulative lifetime 
dose >120 mg/m2), other strongly immunosup-
pressive treatments with very long-lasting effects 
Any time 
Any BTK inhibitor 
Any time 
6. Has a history or presence of significant other concomitant illness that, according to the PI or 
MAI’s judgment, would adversely affect participation in this study; examples include but are not 
limited to clinically significant cardiovascular, renal, hepatic, or metabolic disease. 
7. Unwilling to allow coded samples to be processed offsite 
8. Unwilling to have coded samples and/or data saved or used in other studies 
5.3 
INCLUSION OF VULNERABLE PARTICIPANTS 

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Selection will be equitable among eligible participants. 
Justification for exclusion of children: Participants under the age of 18 are excluded as progressive MS is 
exceedingly rare in this group, as is the development of rim lesions, suggesting a different biology from 
adult patients. 
Justification for non-inclusion of prisoners: NIH policy does not allow research that is more than minimal 
risk to be conducted in prisoners. 
Justification for exclusion of decisionally impaired adults: Individuals without consent capacity at the time 
of enrollment are not eligible to enroll in this study, as the study requires subjects to complete a large 
number of procedures over a relatively short time period. Patients with multiple sclerosis may lose consent 
capacity with disease progression, and such participants will be allowed to remain in the study. This is 
justified, given the prospect of direct benefit from research participation (Section 2.3.3) and that, at the 
time of enrollment the participants had capacity, agreed to full participation, and chose a surrogate to speak 
on their behalf should they lose capacity. This participant appointed DPA will be invoked should it be 
determined the subject no longer has consent capacity. If participants who receive tolebrutinib perma-
nently lose the capacity to provide on-going consent subsequent to giving initial consent, they may con-
tinue to participate in the study if they have a Durable Power of Attorney (DPA) for health care. 
5.3.1 Participation of NIH Staff of family members of study team members 
NIH employees and staff will not be solicited for participation but will not be excluded if they express the 
desire to enroll. NIH staff and family members of study team members may be enrolled in this study as 
this population meets the study entry criteria. Employees and staff who participate in this protocol during 
work hours will be informed that they must obtain their supervisor’s permission. Neither participation nor 
refusal to participate as a subject in the research will have an effect, either beneficial or adverse, on the 
participant’s employment, training or position at NIH. Protections for employees and staff participating in 
this study include: (1) providing them with the NIH Frequently Asked Questions (FAQs) for Staff Who 
are Considering Participation in NIH Research and request that they review the FAQ document; (2) assur-
ing that there will be no direct solicitation of employees or staff; and (3) monitoring of independent consent 
monitoring by the NIH Human Subjects Protection Unit or Clinical Center Department of Bioethics. Every 
effort will be made to protect participant information, but such information may be available in medical 
records and may be available to authorized users outside of the study team in both an identifiable an uni-
dentifiable manner. The PI will train study staff regarding obtaining and handling potentially sensitive and 
private information about co-workers through staff discussions and written branch/section procedures. 
The NIH Information Sheet on NIH Staff Research Participation will be made available. Please see section 
10.1.3 for consent of NIH Staff. 
5.4 
INCLUSION OF PREGNANT WOMEN, FETUSES OR NEONATES 
Pregnant and lactating women are excluded as the risk of tolebrutinib in pregnancy and lactation is not 
known, and as the risk of MRI — the primary and key secondary outcome measures — would not outweigh 
the potential benefits of the study. Within 24 hours and prior to undergoing any MRI, urine or serum 
specimens from women with childbearing potential will be collected, and pregnancy testing will be per-
formed. 
5.5 
LIFESTYLE CONSIDERATIONS 
During this study, participants are asked to: 
• 
Tolebrutinib cohorts only.  
o For males of reproductive potential, use condoms or other methods to ensure effective 
contraception, and not donate sperm from baseline until 12 weeks after the last dose. 
o During the entire study, participants will be advised not to consume substantial quantities 
of alcohol, defined as >14 grams (1 standard drink) per day in female participants or >28 

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grams (2 standard drinks) per day in male participants on a regular basis. 
• 
All cohorts. For females of reproductive potential, use highly effective contraception. For the 
tolebrutinib cohorts, contraception use should last from at least 1 month prior to dosing until 12 
weeks after the end of tolebrutinib administration. 
5.6 
SCREEN FAILURES 
Screen failures are defined as participants who consent to participate in the clinical trial but are not subse-
quently assigned to the study intervention or entered in the study. A minimal set of screen failure infor-
mation is required to ensure transparent reporting of screen failure participants, to meet the Consolidated 
Standards of Reporting Trials (CONSORT) publishing requirements and to respond to queries from regu-
latory authorities. Minimal information includes demography, screen failure details, eligibility criteria, 
and any serious adverse event (SAE). 
Individuals who do not meet the criteria for participation in this trial (screen failure) may be rescreened. 
Rescreened participants should be assigned the same participant number used for the initial screening. 
5.7 
STRATEGIES FOR RECRUITMENT AND RETENTION 
Candidates for participation may enter this protocol in the following ways: 
Self-referral. Advertisements and notifications may be placed on NIH or outside websites, either through 
established Clinical Center mechanisms or following specific approval by the IRB. 
• 
The Clinical Center Recruitment Office and NIH Clinical Research Volunteer Program. Recruit-
ment may be conducted by the NIH Office of Patient Recruitment (OPR). The OPR may distrib-
ute recruitment information via the internet to neurology clinics, patient support groups, relevant 
websites, or other institutions or individuals. Recruitment strategies to be utilized by the OPR 
will include flyers, a Public Service Announcement (PSA), NIH newsletters, ResearchMatch, 
Clinical Center Facebook, Twitter, CC News/NIH Record, and LISTSERVs. 
• 
Through ongoing Neuroimmunology Clinic protocols. In this case, individuals with MS thought 
by the study team to meet eligibility criteria will be recruited by direct inquiry. 
Given the small sample size and short duration of this study, as well as the current unavailability of effec-
tive treatments for chronic inflammation in MS and the high number (>50) of MS patients taking anti-
CD20 therapy in the Neuroimmunology Clinic, recruitment is anticipated to be straightforward and to 
accrue over the course of 18–24 months or sooner. The study team may reach out to clinicians who treat 
people with MS. Subject to IRB rules and specific approval, study information may also be placed in 
locations, such as National MS Society newsletters and websites, where it may be seen by prospective 
participants. In this event, any materials prepared for recruitment purposes will be submitted to the IRB 
for review and approval. 
NIH employees may also be recruited. NIH employees and staff will not be directly solicited by supervi-
sors. Co-workers of investigators will not be directly solicited. NIH employees are required to abide by 
NIH Policy Manual 2300-630-3 “Leave Policy for NIH Employees Participating in NIH Medical Research 
Studies.” 
5.7.1 Costs 
The participant is not expected to be responsible for any costs due to participation in this research. Ongoing 
treatment with anti-CD20 antibody therapy, and any monitoring associated with standard of care for this 
treatment not already performed as a study procedure, will not be covered by the NIH. 
5.7.2 Compensation 
There is no compensation for participation in this study. Travel/accommodations for the participant may 
be provided for out-of-town participants or for those for whom traveling to NIH is a hardship. In such 

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cases, travel/lodging for the participant and one traveling caregiver may also be provided. If unexpected 
travel related expenses occur, participants may be provided with a voucher. 
Employees and staff who participate during work hours must have permission from their supervisor and 
cannot receive compensation. NIH employees must either participate outside of work hours or take leave 
in order to receive compensation. NIH employees must take leave in order to accompany family members 
to appointments for research participation during their duty hours. 
6 
STUDY INTERVENTION 
6.1 
STUDY INTERVENTIONS(S) ADMINISTRATION 
6.1.1 Study Intervention Description 
This study intervention includes an investigational medical product (IMP), a non-investigational medicinal 
product (NIMP), and potentially an investigational MRI scanner. 
6.1.1.1 Investigational medicinal product 
The IMP is tolebrutinib, provided in the form of 60-mg tablets. 
6.1.1.2 Non-investigational medicinal product 
Approved anti-CD20 antibody therapy for participants not in the tolebrutinib cohort. Participants who 
wish to do so may, in consultation with their primary non-NIH clinician, switch to a different anti-CD20 
therapy after week 48. 
6.1.1.3 Devices 
The primary 7-tesla MRI scanner and relevant accessories, as well as the pulse sequences used in this 
study, are FDA-approved, and their use conforms to the corresponding FDA labels. 
If for any reason the primary 7-tesla MRI scanner is not available, another 7-tesla or (less preferred) 3-
tesla scanner may be used under conditions designated by the FDA as constituting nonsignificant risk 
under 21 CFR 812.2(b)(1). Acquisition parameters may be modified within the permitted range. These 
studies may also involve image reconstruction and analysis software, including research pulse sequences. 
In addition, the following non-FDA-approved systems may be used in this study under conditions desig-
nated by the FDA as constituting nonsignificant risk, with assurances from the manufacturer that all 
measures found in FDA-approved MRI are operational. 
Justification for MRI, image reconstruction and analysis software, and head coil non-significant risk 
(NSR) designation 
• 
Magnetic resonance imaging system (7T and 3T MRI) operating in research mode and with re-
search pulse sequences 
• 
MAGNETOM 7T scanner (manufactured by Siemens) 
• 
Image reconstruction and analysis software 
• 
1Tx 32Rx Head Coil (manufactured by Nova Medical; tested and supplied by Siemens) 
According to 21 CFR 812.3 (m) and FDA “Information Sheet Guidance for IRBs, Clinical Investigators, 
and Sponsors: Significant Risk and Nonsignificant Risk and Nonsignificant Risk Medical Device Studies 
January 2006,” the use of these devices in the study are a Non-significant Risk study. 21 CFR 812.3(m) 
enumerates four criteria for a Significant Risk Device Study; none of these apply to this study: 
• 
is intended as an implant and presents a potential for serious risk to the health, safety, or welfare of 
a subject. 
None of the devices are implants.  
• 
is purported or represented to be for a use in supporting or sustaining human life and presents a 
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None of the devices are for use in supporting or sustaining human life.  
• 
is for a use of substantial importance in diagnosing, curing, mitigating, or treating disease, or oth-
erwise preventing impairment of human health and presents a potential for serious risk to the health, 
safety, or welfare of a subject. 
The investigational use of the devices is not of substantial importance in diagnosing, curing, miti-
gating, or treating disease, or otherwise preventing impairment of human health.  
• 
otherwise presents a potential for serious risk to the health, safety or welfare of a subject.  
The protocol will comply with the abbreviated IDE requirements under 21 CFR 812.2(b). 
6.1.2 Dosing and Administration 
6.1.2.1 Dose Escalation 
As of January 20, 2023, participants (n=4) who started tolebrutinib 60 mg/day and previously escalated to 
120 mg/day† at Week 48 will remain at that dose. Participants (n=3) who initiated tolebrutinib 60 mg/day 
and did not escalate to 120 mg/day due to the partial clinical hold will be followed on study for an addi-
tional 48 weeks, according to the schedule of the Initial Cohort. They will furthermore be eligible to con-
tinue taking tolebrutinib 60 mg/day until tolebrutinib becomes FDA-approved or the clinical development 
program is terminated. 
6.1.2.2 Dose Limiting Toxicity 
Dose-limiting toxicity has not been established. 
6.1.2.3 Dose Modifications 
Should tolebrutinib 120 mg/day prove intolerable, the dose may temporarily or permanently be reduced 
to 60 mg/day. Participants will contribute to subsequent data analyses even if the dose is reduced. Treat-
ment might need to be interrupted or permanently discontinued if deemed necessary due to an adverse 
event (Sections 7 and 8.4). 
6.1.2.4 Drug Administration 
As of January 20, 2023, participants (n=3) who have received one 60-mg tablet of tolebrutinib per day 
will no longer have the option to increase to 120 mg (2 tablets) per day at Week 481. The tablet(s) should 
be taken orally with food. The time of day should be as consistent as possible throughout the study. Missed 
doses will not be made up. 
Study interventions will be dispensed at regular site visits. Tolebrutinib dosing will continue for the dura-
tion of the study and may be continued thereafter until tolebrutinib is either marketed or its development 
halted. 
6.1.2.5 Partial Clinical Hold 
On June 29, 2022, we were informed by Sanofi that as of June 27, 2022, new enrollment was being halted 
across all 5 of their US phase 3 trials of tolebrutinib, and that all participants dosed after April 29, 2022 in 
the US would be required to stop tolebrutinib but would continue for observation on the trials. Sanofi staff 
detailed a call earlier in the week, on which the FDA verbally communicated a partial clinical hold to the 
Sponsor. The partial clinical hold was enacted after internal discussions regarding four participants with 
evidence of drug-induced liver injury (DILI), and the FDA outlined specific steps that Sanofi could take 
to support lifting the hold.  
On July 12, 2022, the FDA issued a partial clinical hold to the NINDS IND as well, with identical stipu-
lations to the Sanofi hold. As such, until the hold is lifted, we will not initiate new subjects on tolebrutinib. 
However, as no participants in our study had been taking tolebrutinib for less than 60 days at the time of 
 
† See Section 6.1.2.5 
 

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the FDA partial clinical hold, the FDA does not require that we stop tolebrutinib for any participant in our 
trial. Furthermore, although not specifically stipulated by the FDA, we have elected to defer dose escala-
tion from 60 to 120 mg (the “week 48” time point) until the partial clinical hold is lifted or modified; once 
the dose is escalated, however, the trial clock will restart. 
On January 20, 2023, the FDA requested a revision to the protocol to remove the potential for dose esca-
lation. Participants who have initiated tolebrutinib 60 mg and escalated to 120 mg/day will remain at that 
dose. The 3 remaining participants who initiated tolebrutinib 60 mg will remain at 60 mg and not be 
escalated to 120 mg/day.  
6.2 
PREPARATION/HANDLING/STORAGE/ACCOUNTABILITY 
6.2.1 Acquisition and Accountability 
Sanofi-Genzyme will ship tolebrutinib 60-mg tablets directly to the NIH clinical Center Pharmacy. 
6.2.2 Formulation, Appearance, Packaging, and Labeling 
Tolebrutinib tablets will be packaged in blister packs protected by a wallet. Each wallet contains 20 tablets 
which are dispensed in sufficient amount to cover patient treatment until the next study visit. Each wallet 
will be labeled. The packaging may be updated during the course of the study. 
6.2.3 Product Storage and Stability 
Tolebrutinib kits must be stored between 36°F and 86°F. Procedures for temperature monitoring and ex-
cursion management will be followed as per Sanofi’s pharmacy manual. Tolebrutinib kits will be stored 
in a secure location in accordance with local regulations, labeling specifications, policies and procedures. 
6.2.4 Preparation 
Tolebrutinib will be supplied as a 60-mg oral tablets and will not require any preparation. 
6.3 
MEASURES TO MINIMIZE BIAS: RANDOMIZATION AND BLINDING 
Participants will not be randomized in this study. Up to 10 adults with MS who are on stable disease 
modifying treatment with anti-CD20 antibody therapy and are within 6 months of their most recent dose, 
have at least one paramagnetic rim lesion on 7-tesla magnetic resonance imaging (MRI), and have devel-
oped no new white matter lesions or clinical relapses for at least 6 months, will receive treatment with 
tolebrutinib  60 mg/day or escalating to 120 mg/day and agree to forego further anti-CD20 or other disease-
modifying therapy for the duration of the trial.‡ A comparison cohort of individuals who meet enrollment 
criteria (other than tolebrutinib contraindications) but choose not to take tolebrutinib will continue to re-
ceive their current anti-CD20 therapy. 
The study is unblinded for the participant and investigators, except for the investigators performing anal-
ysis of the raw MRI data for the primary and secondary outcomes, who will be blinded to the time point 
at which the data were acquired. If these investigators become unblinded, their analysis will be scrapped 
and redone by blinded investigators. 
6.4 
STUDY INTERVENTION COMPLIANCE 
At the end of the baseline visit (Day 0), the participant will receive the study intervention for the following 
144 weeks (Cohort A) before entering the extension phase. At each following visit, a new kit will be 
dispensed, and the participant will self-administer the medication. Participants will be asked to track daily 
dosage either electronically or in a written format per their preference. They will be provided with a tem-
plate drug diary, which they may opt to use. Remaining pills will be counted at each follow-up visit to 
assess overall drug compliance. 
6.5 
CONCOMITANT THERAPY 
 
‡ See Section 6.1.2.5 

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Concomitant therapies (including over-the-counter or prescription medicines, vitamins, and/or herbal sup-
plements) will be reviewed at each study visit and documented in the clinical chart. 
Use of certain medications will be restricted during study participation, as detailed in Section 5.2 and 
below. 
The following medications will be prohibited throughout study participation in the tolebrutinib cohorts: 
• 
Other MS disease-modifying treatments 
• 
Acetylsalicylic acid (aspirin) 
• 
Anti-platelet drugs (e.g., clopidogrel) 
• 
Anticoagulants, including: 
o Warfarin 
o Heparin, including low-molecular-weight heparins 
o Dabigatran 
o Apixaban, edoxaban, rivaroxaban 
• 
Potent and moderate inducers and inhibitors of cytochrome P450 3A (CYP3A) or potent inhib-
itors of CYP2C8 hepatic enzymes as listed in Appendix 1. 
In the tolebrutinib cohorts, short courses (up to 5 days) of NSAIDs (other than acetylsalicylic acid) at the 
recommended dose may be used if clinically indicated. Standard treatment of MS relapse with high dose 
glucocorticoids is permitted. 
7 
STUDY INTERVENTION DISCONTINUATION AND PARTICIPANT DISCONTINUA-
TION/WITHDRAWAL 
7.1 
DISCONTINUATION OF STUDY INTERVENTION 
Participants are free to withdraw from participation in the study at any time upon request. 
The PI or MAI may discontinue or withdraw a participant from the study for any of the following reasons: 
• 
Disease activity or progression that requires discontinuation of the study intervention 
• 
If any clinical adverse event (AE), laboratory abnormality, or other medical condition or situation 
occurs such that continued participation in the study would not be in the best interest of the 
participant 
• 
Investigator judgment for safety, behavioral, compliance, or administrative reasons 
• 
Positive pregnancy test 
The reason for withdrawal or discontinuation will be documented in the medical record. Participants will 
be asked to return for a follow-up visit within 3 months, and ideally within 1 month after discontinuation 
of the intervention. 
Events of Special Interest (Section 8.4.7) will follow the algorithm outlined in Appendix 2. 
7.1.1 Definitive discontinuation 
Definitive discontinuation is any IMP discontinuation associated with the definitive decision of the PI not 
to re-expose the participant to the IMP at any time during the study, or from the participant not to be re-
exposed to the IMP, whatever the reason. 
Definitive discontinuation will ensue for any confirmed treatment-related serious adverse event. 
If discontinuation is due to adverse event preventing further exposure to the IMP, the participant will be 
followed up to recovery or stabilization of the event. 
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procedure normally planned for Week 24 if prior to Week 24, or the next protocol timepoint if they drop 
out at any later time. Details are provided in the Schedule of Activities (Section 1.3). 
7.1.2 Temporary discontinuation 
Temporary IMP discontinuation will ensue during evaluation of any suspected IMP-related serious ad-
verse event. For all temporary IMP discontinuations, the duration of the discontinuation should be rec-
orded by the PI or designee in the appropriate pages of the study record. Temporary discontinuation of 
study drug will be discussed with the IMM. Temporary IMP discontinuation decided by the PI or MAI 
corresponds to >1 dose not administered to the participant. 
The current NIH treatment guidelines recommend against the use of BTK inhibitors in the treatment of 
COVID-19 unless a patient is enrolled in a clinical trial studying that indication. The guidelines are being 
updated regularly. If a trial participant on tolebrutinib treatment is hospitalized for COVID-19, the PI and 
MAI will discuss the case with the treating physician and appropriate experts to determine whether IMP 
will be continued or halted based on patient safety. Participants who are off of tolebrutinib for more than 
12 weeks will not contribute to the primary analysis, although they can resume IMP and trial participation 
when determined by the PI, MAI, and treating physician.  
7.1.2.1 Rechallenge 
Re-initiation of intervention with tolebrutinib may be considered under close and appropriate clinical/and 
or laboratory monitoring if the PI or MAI determine in conjunction with either the study HAC or DSMB 
(see Section 10.6 and Appendix 2), according to his/her best medical judgment, that the responsibility of 
tolebrutinib in the occurrence of the concerned event was unlikely and if the selection criteria for the study 
are still met. 
7.2 
PARTICIPANT DISCONTINUATION/WITHDRAWAL FROM THE STUDY 
The reason and date of any study withdrawal will be documented in the study record. 
Participants who sign the informed consent form but do not receive tolebrutinib may be replaced and 
followed in the non-tolebrutinib cohort.  
7.3 
LOST TO FOLLOW-UP 
A participant will be considered lost to follow-up if he or she fails to return for two scheduled visits and 
is unable to be contacted by the study site staff after 3 attempts. 
The following actions must be taken if a participant fails to return to the clinic for a required study visit: 
• 
An investigator or designee will attempt to contact the participant within 1 month to reschedule 
the missed visit, counsel the participant on the importance of maintaining the assigned visit 
schedule, and ascertain if the participant wishes to and/or should continue in the study. 
• 
Before a participant is deemed lost to follow-up, the investigator or designee will make every 
effort to regain contact with the participant. These contact attempts should be documented in the 
participant’s medical record or study file. 
• 
Should the participant continue to be unreachable, he/she will be considered to have withdrawn 
from the study with a primary reason of lost to follow-up. 
8 
STUDY ASSESSMENTS AND PROCEDURES 
8.1 
SCREENING PROCEDURES 
Candidates for this study are screened under the natural history protocol 89-N-0045. Data collected during 
screening may be used for baseline measurements and/or combined with data collected in this protocol for 
exploratory analyses. Screening procedures/evaluations must be performed within 6 months prior to en-
rollment. Screening will occur only after the participant has signed the consent for 89-N-0045. 

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8.2 
EFFICACY ASSESSMENTS 
Assessments are performed according to the Schedule of Activities, Section 1.3. In the event that data or 
samples are found to be technically inadequate for a particular procedure, procedures in Section 8.2 may 
be repeated twice. 
8.2.1 Clinical Evaluations 
History and physical. This is a targeted history and neurological examination to allow calculation of the 
Expanded Disability Status Scale and Scripps Neurological Rating Scale and must be performed by a 
credentialed provider. 
Clinical disability scales. These include, but are not limited to, 9-hole peg test (9HPT), timed 25- foot 
walk (T25W), and symbol digit modalities test (SDMT). The paced auditory serial addition test (PASAT) 
and timed up-and-go (TUG) tests may also be performed. 
Magnetic resonance imaging. Details regarding the use of MRI are further described in Section 6.1.1. For 
women of childbearing age, urine or serum pregnancy testing is performed prior to initial study drug dos-
ing and to all MRI scans. 
8.2.2 Biospecimen Evaluations 
Not applicable. 
8.2.3 Correlative Studies for Research 
Research blood work, cerebrospinal fluid, and urine testing are used for exploratory outcomes in this study. 
Research blood work and urine. In addition to samples sent to the NIH Clinical Center lab for safety 
evaluation (Section 8.3), up to 150 ml of whole blood, as well as a urine sample, may be collected at each 
study visit for research purposes and processed in the NINDS Viral Immunology Section and/or Transla-
tional Neuroradiology Section. The amount of blood that may be drawn for research purposes will not 
exceed 10.5 mL/kg or 550 mL, whichever is smaller, over any 8-week period. 
Research lumbar puncture. Lumbar puncture may be performed at the bedside or under fluoroscopy if 
required for scheduling or if judged by the study team to be in the best interest of the participant. In addition 
to samples sent to the NIH Clinical Center lab for safety evaluation (Section 8.3), up to 25 ml of CSF are 
collected for research purposes and processed in the NINDS Viral Immunology Section and/or Transla-
tional Neuroradiology Section. 
Research assays are focused primarily on immune-cell subsets and their products and may include, but are 
not limited to, flow cytometry and protein measurements (e.g. ELISA, MesoScale, Single Molecule Array, 
mass spectrometry). Bulk and single-cell and/or single-nucleus RNA sequencing assays, as well as epige-
netic assays (e.g. ATAC-Seq), may also be performed. Assays to assess products of glia and neurons (e.g. 
neurofilament light chain) may also be developed and performed. Specimens are preserved and patched 
for subsequent analysis whenever possible, but some assays (e.g. flow cytometry and single-cell RNA 
sequencing) may require use of fresh samples. Cell lines are not expected to be created as part of this 
protocol, but they may be created for further exploratory analyses. 
8.2.4 Samples for Genetic/Genomic Analysis 
Not applicable. 
8.3 
SAFETY AND OTHER ASSESSMENTS 
History and physical. Interval history is obtained at visits over the course of the study to assess for adverse 
events. Focused neurological and additional portions of the physical examination are performed if clini-
cally warranted or to follow up on any issues reported. These procedures are performed by a credentialed 
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Vital signs. Temperature, pulse, blood pressure, and respiratory rate are assessed and recorded in the study 
record. 
Electrocardiogram (ECG). A 12-lead ECG is obtained using an ECG machine that automatically calcu-
lates the heart rate and measures PR, QRS, QT, and QTc intervals. At least one longer rhythm monitoring 
recording should be part of each ECG testing. 
Magnetic resonance imaging. MRI is obtained without intravenous administration of an FDA-approved 
gadolinium- based contrast agent. However, an FDA-approved, gadolinium-based contrast agent may be 
given for clinical purposes (for example to investigate new neurological symptoms), if judged warranted 
by the evaluating clinician and provided that there are no contraindications for the subject to receive a 
contrast agent. Details regarding the use of MRI are further described in Section 6.1.1. For women of 
childbearing age, urine or serum pregnancy testing is performed prior to initial study drug dosing and to 
all MRI scans. MRI scans will be read by a neuroradiologist and a report entered into the NIH clinical 
system. 
Laboratory work. Blood and urine samples will be sent to the NIH Clinical Center lab as per study sched-
ule, or they may be evaluated at an outside facility. For the tolebrutinib cohorts, lab work should include 
complete blood count with differential (including lymphocyte subsets), blood chemistry, to include liver 
function tests, and ferritin, transferrin, amylase, lipase, JCV Ab, JCV PCR (blood and urine), and quanti-
tative immunoglobulins. Serum iron panel (iron, ferritin, transferrin saturation, TIBC – total iron-binding 
capacity), QuantiFERON® TB Gold Test, serology for hepatitis and/or confirmatory testing, HIV and 
other infectious diseases to confirm inclusion and exclusionary conditions may be performed at baseline 
and throughout the protocol as required. TBNK assays may be performed at the time of 7T MRI for the 
tolebrutinib cohorts. For the control cohort, lab work should include complete blood count with differential 
(including lymphocyte subsets), blood chemistry as needed for MRI, JCV Ab, JCV PCR (blood and urine), 
and quantitative immunoglobulins. “Safety labs,” as designated in the Schedule of Activities, include com-
plete blood count and blood chemistry including liver function tests. “Liver-specific safety labs” refer to 
liver function tests (AST, ALT, alkaline phosphatase, and total bilirubin). Additional labs may be ordered 
when clinically indicated. 
Lumbar puncture. Lumbar puncture may be performed at the bedside or under fluoroscopy if required for 
scheduling or if judged by the study team to be in the best interest of the participant. Samples are sent to 
the NIH Clinical Center lab for cell count, protein, and glucose. 
Assessment of study intervention adherence. See Study Intervention Compliance, Section 6.4. 
Assessment of adverse events. Adverse events, including serious adverse events, will be followed up as 
clinically warranted, including possibly by telephone or other method of communication and additional 
visits to the NIH. 
Clinically relevant results of laboratory or radiological evaluations performed in this protocol will be pro-
vided to participants, along with a recommendation for next step (including potential follow- up at NIH or 
elsewhere). 
In the event that circumstances beyond our control preclude the travel of one or more of the study partic-
ipants to the NIH Clinical Center for a visit, or otherwise would put their health at greater risk (i.e. epi-
demic or pandemic), we will endeavor to establish capabilities for remote visits (using NIH approved 
platforms). Specifically, for safety visits, the study team will arrange for local laboratory studies to be 
done, and conduct a telehealth visit with the participant. Unscheduled visits, due to safety, may also be 
conducted remotely through telehealth and/or offsite laboratory and radiologic studies and/or in conjunc-
tion with a local physician with the guidance of the study PI and medically responsible investigator. The 
laboratory studies may be performed through LabCorp, Quest, or with the local physician, and results will 
be sent to the study team for safety monitoring and oversight. Radiology studies will be arranged through 
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travel to the NIH is not possible. 
8.4 
ADVERSE EVENTS AND SERIOUS ADVERSE EVENTS 
8.4.1 Definition of Adverse Event 
Adverse event means any untoward medical occurrence associated with the use of an intervention in hu-
mans, whether or not considered intervention-related (21 CFR 312.32 (a)). The descriptions and grading 
scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 
will be utilized for AE reporting. 
8.4.2 Definition of Serious Adverse Events (SAE) 
An adverse event (AE) or suspected adverse reaction is considered "serious" if, in the view of either the 
investigator or sponsor, it results in any of the following outcomes: death, a life- threatening adverse event, 
inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity 
or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth 
defect. Important medical events that may not result in death, be life-threatening, or require hospitalization 
may be considered serious when, based upon appropriate medical judgment, they may jeopardize the par-
ticipant and may require medical or surgical intervention to prevent one of the outcomes listed in this 
definition. Examples of such medical events include allergic bronchospasm requiring intensive treatment 
in an emergency room or at home, blood dyscrasias or convulsions that do not result in inpatient hospital-
ization, or the development of drug dependency or drug abuse. 
8.4.3 Classification of an Adverse Event 
8.4.3.1 Severity of Event 
For adverse events (AEs) not included in the protocol defined grading system, the following guidelines 
will be used to describe severity. 
• 
Mild – Events require minimal or no treatment and do not interfere with the participant’s daily 
activities. 
• 
Moderate – Events result in a low level of inconvenience or concern with the therapeutic 
measures. Moderate events may cause some interference with functioning. 
• 
Severe – Events interrupt a participant’s usual daily activity and may require systemic drug ther-
apy or other treatment. Severe events are usually potentially life-threatening or incapacitating. 
Of note, the term “severe” does not necessarily equate to “serious.” 
8.4.3.2 Relationship to Study Intervention 
All adverse events (AEs) must have their relationship to study intervention assessed by the investigator 
who examines and evaluates the participant based on temporal relationship and his/her clinical judgment. 
The degree of certainty about causality will be graded using the categories below. In a clinical trial, the 
study product must always be suspect. 
• 
Definitely Related – There is clear evidence to suggest a causal relationship, and other possible 
contributing factors can be ruled out. The clinical event, including an abnormal laboratory test 
result, occurs in a plausible time relationship to study intervention administration and cannot be 
explained by concurrent disease or other drugs or chemicals. The response to withdrawal of the 
study intervention (dechallenge) should be clinically plausible. The event must be pharmacolog-
ically or phenomenologically definitive, with use of a satisfactory rechallenge procedure if nec-
essary. 
• 
Probably Related – There is evidence to suggest a causal relationship, and the influence of other 
factors is unlikely. The clinical event, including an abnormal laboratory test result, occurs within 
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concurrent disease or other drugs or chemicals, and follows a clinically reasonable response on 
withdrawal (dechallenge). Rechallenge information is not required to fulfill this definition. 
• 
Possibly Related – There is some evidence to suggest a causal relationship (e.g., the event oc-
curred within a reasonable time after administration of the trial medication). However, other fac-
tors may have contributed to the event (e.g., the participant’s clinical condition, other concomi-
tant events). Although an AE may rate only as “possibly related” soon after discovery, it can be 
flagged as requiring more information and later be upgraded to “probably related” or “definitely 
related,” as appropriate.  
• 
Unlikely to Be Related – A clinical event, including an abnormal laboratory test result, whose 
temporal relationship to study intervention administration makes a causal relationship improba-
ble (e.g., the event did not occur within a reasonable time after administration of the study inter-
vention) and in which other drugs or chemicals or underlying disease provides plausible expla-
nations (e.g., the participant’s clinical condition, other concomitant treatments). 
• 
Not Related – The AE is completely independent of study intervention administration, and/or 
evidence exists that the event is definitely related to another etiology. There must be an alterna-
tive, definitive etiology documented by the clinician. 
8.4.3.3 Expectedness 
An AE will be considered unexpected if the nature, severity, or frequency of the event is not consistent 
with the risk information previously described for the study intervention in the protocol or IB, according 
to FDA guidance (https://www.fda.gov/regulatory-information/search-fda-guidance-documents/safety-
reporting-requirements-inds-investigational-new-drug-applications-and-babe). Events described in the lit-
erature, but not in the protocol or IB, will be considered unexpected for the purpose of this reporting. The 
PI will make the initial determination, along with the IMM. The NINDS DSMB will make final decisions 
of expectedness and relatedness in conjunction with the Sponsor, normally at the time of routine DSMB 
review. For all SAEs and high-grade AEs (AE grade 3 or above), the DSMB will come to a determination 
of expectedness and relatedness within ideally within 48 hours, but no more than within 7 days, of notifi-
cation by the PI. 
All SAEs/SUSARS will be reported to the Study Sponsor or his delegate. Form 3500 (MedWatch) may 
be used for all potential SUSARs submitted to the Study Sponsor. 
8.4.4 Time Period and Frequency for Event Assessment and Follow-Up 
The occurrence of an adverse event (AE) or serious adverse event (SAE) may come to the attention of 
study personnel during study visits and interviews of a study participant presenting for medical care, or 
upon review by a study monitor. 
All AEs including local and systemic reactions not meeting the criteria for SAEs will be captured on the 
appropriate case report form (CRF). Information to be collected includes event description, time of onset, 
clinician’s assessment of severity, relationship to study product (assessed only by those with the training 
and authority to make a diagnosis), and time of resolution/stabilization of the event. All AEs occurring 
while on study must be documented appropriately regardless of relationship. All AEs will be followed to 
adequate resolution. 
Any medical condition that is present at the time that the participant is screened will be considered as 
baseline and not reported as an AE. However, if the study participant’s condition deteriorates at any time 
during the study, it will be recorded as an AE. 
Changes in the severity of an AE will be documented to allow an assessment of the duration of the event 
at each level of severity to be performed. AEs characterized as intermittent require documentation of onset 
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The investigator will record all reportable events with start dates occurring any time after informed consent 
is obtained until 7 (for non-serious AEs) or 30 days (for SAEs) after the last day of study participation. At 
each study visit, the investigator will inquire about the occurrence of AE/SAEs since the last visit. Events 
will be followed for outcome information until resolution or stabilization. 
8.4.5 Adverse Event Reporting 
The Principal Investigator or delegated AI is responsible for detecting, documenting, and reporting unan-
ticipated problems, adverse events (AEs), including serious adverse events (SAEs), and deviations in ac-
cordance with NIH policy, IRB requirements, and federal regulations. Relatedness to the research of all 
serious adverse events will initially be determined by the PI or delegated AI in consultation with the IMM. 
Final determinations will be made by the DSMB in conjunction with the sponsor. All high-grade AEs 
(grade 3 and above) and all SAEs will be forwarded to the IMM and the DSMB within 2 business days, 
regardless of initial determination. 
The IMM and DSMB should receive the written initial determination and justification from the PI at the 
time of initial reporting. The IMM and DSMB will receive updates from the PI regarding potential changes 
to expectedness or relatedness, and safety, within 48 hours, but not later than 7 days. 
All AEs (serious and non-serious) that are either related or possibly related to research procedures; proto-
col deviations; and unanticipated problems will be summarized and reported at the time of continuing 
review. 
 
8.4.6 Serious Adverse Event Reporting 
The study investigator will immediately (but no later than 24 hours) report to the sponsor any serious 
adverse event, whether or not considered study intervention related, including those listed in the protocol 
or investigator brochure and must include an assessment of whether there is a reasonable possibility that 
the study intervention caused the event. Study endpoints that are serious adverse events (e.g., all-cause 
mortality) must be reported in accordance with the protocol unless there is evidence suggesting a causal 
relationship between the study intervention and the event (e.g., death from anaphylaxis). In that case, the 
investigator must immediately report the event to the sponsor. 
All serious adverse events (SAEs) will be followed until satisfactory resolution or until the site investigator 
deems the event to be chronic or the participant is stable. Other supporting documentation of the event 
may be requested by the study sponsor and should be provided as soon as possible. 
The study sponsor will be responsible for notifying the Food and Drug Administration (FDA) of any un-
expected fatal or life-threatening suspected adverse reaction as soon as possible, but in no case later than 
7 calendar days after the sponsor's initial receipt of the information. In addition, the sponsor must notify 
FDA and all participating investigators in an Investigational New Drug (IND) safety report of potential 
serious risks, from clinical trials or any other source, as soon as possible, but in no case later than 15 
calendar days after the sponsor determines that the information qualifies for reporting. 
8.4.7 Events of Special Interest  
The following are defined as Events of Special Interest (ESI). Once identified, they follow the algorithm 
outlined in Appendix 2 and separate HAC charter. 
• 
Increase in alanine transaminase (ALT) > 3xULN  
• 
Increase in aspartate transaminase (AST) > 3xULN  
• 
Increase in total bilirubin Level (TBL) > 2xULN 
 
Expedited (<15 days) reports will be sent to the FDA for any cases with transaminases >8x ULN or >3x 
ULN with total bilirubin >2x ULN.  

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8.4.8 Reporting of Pregnancy 
Pregnancy of a female participant as well as pregnancy occurring in a female partner of a male participant 
is reported as an AE and is qualified and reported as an SAE only if it fulfills one of the seriousness criteria 
(Section 8.4.2). In the event of pregnancy in a female participant, tolebrutinib should be discontinued. 
Follow up of the pregnancy in a female participant or in a female partner of a male participant is mandatory 
until the outcome has been determined. 
8.5 
UNANTICIPATED PROBLEMS 
8.5.1 Definition of Unanticipated Problems (UP) 
Any incident, experience, or outcome that meets all of the following criteria: 
• 
Unexpected in terms of nature, severity, or frequency given (a) the research procedures that are 
described in the protocol-related documents, such as the Institutional Review Board (IRB)-ap-
proved research protocol and informed consent document; and (b) the characteristics of the par-
ticipant population being studied; and 
• 
Related or possibly related to participation in the research (“possibly related” means there is a 
reasonable possibility that the incident, experience, or outcome may have been caused by the 
procedures involved in the research); and 
• 
Suggests that the research places participants or others (which many include research staff, fam-
ily members or other individuals not directly participating in the research) at a greater risk of 
harm (including physical, psychological, economic, or social harm) than was previously known 
or expected. 
8.5.2 Unanticipated Problem Reporting 
The investigator will report unanticipated problems (UPs) to the NIH Institutional Review Board (IRB) as 
per Policy 801. 
8.5.3 NIH Intramural IRB Reporting of IND Safety Reports 
Only IND Safety Reports that meet the definition of an unanticipated problem will need to be reported to 
the NIH Intramural IRB. 
9 
STATISTICAL CONSIDERATIONS 
No separate Statistical Analysis Plan has been developed for this protocol. 
9.1 
STATISTICAL HYPOTHESIS 
• 
Primary Endpoint: The per-participant proportion of lesions in which the paramagnetic rim has 
disappeared at the end of 48 weeks of tolebrutinib 60 mg treatment is >0.01. 
• 
Secondary Endpoints: 
o Tolebrutinib 60 and 120 mg doses are safe and tolerable in the study population. 
o The T1 relaxation time has decreased in paramagnetic rim lesions at the end of 96 weeks 
of tolebrutinib 120 mg, relative to non-rim lesions. 
o The size of paramagnetic rim lesions has diminished at the end of 96 weeks of tolebrutinib 
120 mg, relative to non-rim lesions. 
9.2 
SAMPLE SIZE DETERMINATION 
Given our previous natural history data, which indicates that only 1 out of 29 individuals experienced 
subtle changes in at least one paramagnetic rim lesion over a period of ~5 years, we expect that very few 
to no participants in the non-tolebrutinib cohort will experience changes in this study and conservatively 

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estimate this null proportion to be 0.01. Although even a single tolebrutinib-cohort participant experienc-
ing short-term changes would potentially be clinically meaningful, we have powered this study to detect 
disappearance of at least one paramagnetic rim lesion in 2 out of 7 completers (expected proportion: 0.29). 
In this scenario, the interval of (0.0367, 0.7096) will have 95% probability to include the true proportion. 
Thus, the null hypothesis will be rejected if 2 participants experience at least one lesion change. 
To recruit 7 study completers in tolebrutinib Cohort A, we expected to enroll 10 prospective participants 
into that cohort. As of May 2023, the first 7 participants had completed 48 weeks of tolebrutinib 60 mg, 
so no additional participants will be recruited into this Cohort. Participants in the non-tolebrutinib com-
parison cohort (up to 10) will not be replaced if they drop out. We expect the total study duration, including 
the long-term extension (beyond Week 144 for Cohort A, to be approximately 5 years from the time of 
first dosing. 
9.3 
POPULATIONS FOR ANALYSES 
The analysis for the primary and MRI-based secondary outcomes will be performed on all study complet-
ers. The analysis for the safety and tolerability secondary outcome will be performed on all participants 
who take at least one dose of tolebrutinib. Populations for exploratory post-hoc analyses will be defined 
at a later date. 
9.3.1 Evaluable for toxicity 
All participants will be evaluable for toxicity from the time of their first treatment with tolebrutinib. 
9.3.2 Evaluable for objective response 
Only those participants who have received at least one dose of therapy and have had their disease re-
evaluated will be considered evaluable for response. These participants will have their response classified 
according to the definitions in section 9.4. 
9.3.3 Evaluable Non-Target Disease Response 
 Not applicable. 
9.4 
STATISTICAL ANALYSES 
9.4.1 General Approach 
9.4.2 Analysis of the Primary Endpoint 
The primary outcome is the per-patient proportion of lesions in which the paramagnetic rim has disap-
peared at the end of 48 weeks of tolebrutinib 60 mg/day, in comparison to the scan just prior to initiation 
of tolebrutinib dosing. Such participants can be in Cohort A or the Initial Cohort (combined analysis). 
Proportion of diminished/resolved paramagnetic rims is analyzed by investigators blinded to time point, 
reported descriptively, and compared to the assumption of no change off therapy10,11,15,16,20 via a binomial 
exact test. The analysis will be performed in study completers, and by definition no data will be missing. 
A threshold p-value of 0.05 will be taken as a significant change. 
9.4.3 Analysis of the Secondary Endpoints 
To assess the possible repair of chronically inflamed white matter lesions in which inflammation at the 
lesion edge has been modulated by tolebrutinib 120 mg/day, changes in T1 relaxation time within para-
magnetic rim lesions, relative to non-rim lesions, will be determined by analysis of variance or mixed-
effects models. Comparisons are relative to the scan taken just prior to initiation of 120 mg dosing. A 
threshold p-value of 0.025 will be taken as a significant change. 
To assess the possible repair of chronically inflamed white matter lesions in which inflammation at the 
lesion edge has been modulated by tolebrutinib 120 mg/day, changes in size of paramagnetic rim lesions, 
relative to non-rim lesions, will be determined by analysis of variance or mixed-effects models. Compar-
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will be taken as a significant change. 
9.4.4 Safety Analyses 
To assess safety and tolerability, adverse events will be tabulated. 
9.4.5 Baseline Descriptive Statistics  
Not applicable. 
9.4.6 Planned Interim Analyses 
The study may be repowered based on analysis of the per-patient proportion of lesions in which the para-
magnetic rim has disappeared at the end of 48 weeks of tolebrutinib 60 mg/day. If no changes are observed, 
powering will not change.  
Given the FDA partial clinical hold and the inability to recruit additional participants into the tolebrutinib 
cohort, there is no need for an interim analysis as of May 2023. 
9.4.7 Subgroup Analyses 
This is a small study, and subgroup analyses would be meaningless. Changes observed in individual par-
ticipants will be described in the context of the demographic information of those participants. 
9.4.8 Tabulation of Individual Participant Data 
Individual participant data will be listed by measure and time point. 
9.4.9 Exploratory Analyses 
Exploratory analyses based on data collected during this study are considered post-hoc and will be defined 
at a later time point. 
10 REGULATORY AND OPERATIONAL CONSIDERATIONS 
10.1 INFORMED CONSENT PROCESS 
10.1.1 Consent/Assent Procedures and Documentation 
The informed consent document will be provided as a physical or electronic document to the participant 
for review prior to consenting. A designated study investigator will carefully explain the procedures and 
tests involved in this study, and the associated risks, discomforts and benefits. In order to minimize poten-
tial coercion, as much time as is needed to review the document will be given, including an opportunity to 
discuss with friends, family members and/or other advisers, and to ask questions of any designated study 
investigator. A signed informed consent document will be obtained prior to any research activities taking 
place. 
In the event that circumstances beyond our control preclude the travel to the NIH Clinical Center for a 
visit, or otherwise would put their health at greater risk (i.e. epidemic or pandemic), we will endeavor to 
establish capabilities for remote consent. The initial consent process as well as reconsent, when required, 
may take place in person or remotely (e.g., via telephone or other NIH approved remote platforms used in 
compliance with policy, including HRPP Policy 303) per discretion of the designated study investigator 
with the agreement of the participant. 
A physical copy of the consent form may be sent to the subject if a telephone consent process is used. The 
consent interview may then be conducted when the subject can read the consent form during the discus-
sion. Whether in person or remote, the privacy of the subject will be maintained. Consenting investigators 
(and participant, when in person) will be located in a private area (e.g., clinic consult room). When consent 
is conducted remotely, the participant will be informed of the private nature of the discussion and will be 
encouraged to relocate to a more private setting if needed. If the consent process is occurring remotely, 
participants and investigators will view individual copies of the approved consent document on screens at 
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co-located but this is not required. 
Note: When required, the witness signature will be obtained similarly as described for the investigator and 
participant below. 
 
Consent will be documented with required signatures on the physical copy of the consent (which includes 
the printout of an electronic document sent to the participant), or on the electronic document. The process 
for documenting signatures on an electronic document is described below. 
When an electronic document is used for the documentation of consent, this study will use the iMedCon-
sent platform which is 21 CFR, Part 11 compliant to obtain the required signatures. During the consent 
process, participants and investigators will view the same document simultaneously in their respective 
locations.  
The identity of the participant will be determined by a prompt which will require the provision of infor-
mation from an official identification document, prior to obtaining the signature. Both the investigator and 
the participant will sign the electronic document using a finger, stylus or mouse.  
A copy of the informed consent document signed and dated by the subject are given to the subject. Con-
firmation of a subject’s informed consent is documented in the subject’s medical records prior to any 
testing under this protocol. 
When possible, consent will be obtained by an individual in a non-supervisory relationship with the sub-
ject. When consent is conducted, a third party (e.g., a consent monitor) will be present to observe the 
consent process. This may be achieved by one of the following methods: 
• A consent monitor from the CC Department of Bioethics Consultation Service or by a Clinical 
Research Advocate from the NIMH Human Subjects Protection Unit (HSPU), or 
• Another party independent of the research team (such as an IC monitor), or 
• If a consent monitor is not available, the consent process will be observed by another qualified 
investigator on the study who is independent of the NIH staff member’s work unit and not a 
supervisor to the NIH staff member. If no such person exists, consent observation may be per-
formed by a qualified investigator on the study. 
The consent form contains all required elements. A single consent document, for the patient population, 
is submitted with this protocol. No special documents are needed. 
10.1.2 Consent for minors when they reach the age of majority 
 Not applicable. 
10.1.3 Considerations for Consent of NIH staff, or family members of study team members 
Consent for NIH staff will be obtained as detailed above with following additional protections: 
Consent from staff members will be obtained by an individual independent of the staff member’s team 
whenever possible. Otherwise, the consent procedure will be independently monitored by the CC Depart-
ment of Bioethics Consultation Service in order to minimize the risk of undue pressure on the staff mem-
ber. 
10.1.4 Consent of subjects who are, or become, decisionally impaired 
Adults unable to give consent are excluded from enrolling in the protocol. However, re-consent may be 
necessary and there is a possibility, though unlikely, that subjects could become decisionally impaired. 
For this reason and because there is a prospect of direct benefit from research participation (section 2.3.3), 
all subjects ≥ age 18 will be offered the opportunity to fill in their wishes for research and care, and assign 
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Participation” form so that another person can make decisions about their medical care in the event that 
they become incapacitated or cognitively impaired during the course of the study. Note: The PI or AI will 
contact the NIH Ability to Consent Assessment Team for evaluation as needed for the following: an inde-
pendent assessment of whether an individual has the capacity to provide consent; assistance in identifying 
and assessing an appropriate surrogate when indicated; and/or an assessment of the capacity to appoint a 
surrogate. For those subjects that become incapacitated and do not have pre-determined substitute decision 
maker, the procedures described in NIH HRPP Policy 403 for appointing a surrogate decision maker for 
adult subjects who are (a) decisionally impaired, and (b) who do not have a legal guardian or durable 
power of attorney, will be followed. 
10.2 STUDY DISCONTINUATION AND CLOSURE 
This study may be temporarily suspended or prematurely terminated if the sponsor, IMP manufacturer, 
IRB, and/or FDA communicate new safety data regarding the IMP that requires adjustment of study risk, 
or if multiple participants are required to discontinue the study due to similar IMP-related serious adverse 
events. Decisions will be made in consultation with the sponsor and the Data and Safety Monitoring Board. 
Written notification, documenting the reason for study suspension or termination, will be provided by the 
suspending or terminating party to study participants, the IND sponsor, and regulatory authorities. If the 
study is prematurely terminated or suspended, the PI will promptly inform study participants, the IRB, and 
sponsor and will provide the reason(s) for the termination or suspension. Study participants will be con-
tacted, as applicable, and be informed of changes to study visit schedule. 
Additional circumstances that may warrant termination or suspension include, but are not limited to: 
• 
Determination of unexpected, significant, or unacceptable risk to participants 
• 
Insufficient compliance to protocol requirements 
• 
Data that are not sufficiently complete and/or evaluable 
Study may resume once concerns about safety, protocol compliance, and data quality are addressed, and 
satisfy the sponsor, IRB and/or FDA. 
10.3 CONFIDENTIALITY AND PRIVACY 
Participant confidentiality and privacy is strictly held in trust by the participating investigators, their staff, 
and the sponsor(s). This confidentiality is extended to cover testing of biological samples and genetic tests 
in addition to the clinical information relating to participants. Therefore, the study protocol, documenta-
tion, data, and all other information generated will be held in strict confidence. No information concerning 
the study or the data will be released to any unauthorized third party without prior written approval of the 
sponsor. 
All research activities will be conducted in as private a setting as possible. 
The study monitor, other authorized representatives of the sponsor, representatives of the Institutional 
Review Board (IRB), and/or regulatory agencies may inspect all documents and records required to be 
maintained by the investigator, including but not limited to, medical records (office, clinic, or hospital) 
and pharmacy records for the participants in this study. The clinical study site will permit access to such 
records. 
The study participant’s contact information will be securely stored at the NINDS Neuroimmunology 
Clinic and affiliated labs in the NINDS Division of Neuroimmunology and Neurovirology for internal use 
during the study. At the end of the study, all records will continue to be kept in a secure location for as 
long a period as dictated by the reviewing IRB, Institutional policies, or sponsor requirements. 
Study participant research data, which is for purposes of statistical analysis and scientific reporting, will 
be transmitted to and stored at the NINDS Clinical Trials Unit. This, as well as data and samples shared 
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will not include the participant’s contact or identifying information. Rather, individual participants and 
their research data will be identified by a unique study identification number, the key to which is kept in 
the NINDS Neuroimmunology Clinic. The study data entry and study management systems used by the 
NINDS Neuroimmunology Clinic and Clinical Trials Unit research staff, as well as third parties, will be 
secured and password protected. At the end of the study, all study databases will be de-identified and 
archived at the NINDS Neuroimmunology Clinic. 
To further protect the privacy of study participants, a Certificate of Confidentiality has been issued by the 
National Institutes of Health (NIH). This certificate protects identifiable research information from forced 
disclosure. It allows the investigator and others who have access to research records to refuse to disclose 
identifying information on research participation in any civil, criminal, administrative, legislative, or other 
proceeding, whether at the federal, state, or local level. By protecting researchers and institutions from 
being compelled to disclose information that would identify research participants, Certificates of Confi-
dentiality help achieve the research objectives and promote participation in studies by helping assure con-
fidentiality and privacy to participants. 
10.4 FUTURE USE OF STORED SPECIMENS AND DATA 
Data and samples collected in this study may be sent to a repository for indefinite storage and may be 
released for research purposes. Participants’ identifying information will not be on such samples or data, 
but the samples and data may be coded with the key kept in a secure area on password- protected computers 
in the NINDS Neuroimmunology Clinic. The samples and data may be used for other research projects, 
including those that are not related to MS. Genetic testing will not be performed from samples obtained 
solely for this study. Participants who do not want samples and data to be used for other projects should 
not participate in this study. Participants who withdraw from this research study before it is completed 
may ask that their remaining samples, which can be identified as theirs, be destroyed. Data obtained before 
those participants withdraw will be kept. 
10.5 SAFETY OVERSIGHT 
Safety oversight will be under the direction of an Independent Medical Monitor (IMM) and a Data and 
Safety Monitoring Board (DSMB). Additionally, an Independent Hepatology Assessment Committee 
(HAC) will assess liver safety for participants during the course of this trial. The IMM, DSMB, and 
HAC should be independent from the study conduct and free of conflict of interest, or measures should 
be in place to minimize perceived conflict of interest. Individuals with the appropriate expertise will be 
selected to serve as the IMM, or as a member of the DSMB. Safety and date integrity reviews will be 
conducted as described in section 10.6. 
10.6 CLINICAL MONITORING 
Clinical site monitoring is conducted to ensure that the rights and well-being of trial participants are pro-
tected, that the reported trial data are accurate, complete, and verifiable, and that the conduct of the trial is 
in compliance with the currently approved protocol/amendment(s), with International Conference on Har-
monisation Good Clinical Practice (ICH GCP), and with applicable regulatory requirement(s). 
Monitoring for this study will be performed by an Independent Medical Monitor (IMM) and Data and 
Safety Monitoring Board (DSMB). 
Study investigators will evaluate the safety of study subjects throughout the conduct of the study and 
respond to adverse events (AEs) in a timely manner. The PI will review AEs with the study team at Weekly 
Event Reporting Meetings. 
The IMM’s responsibility is to provide independent medical monitoring in a timely fashion. The IMM 
evaluates individual and cumulative participant data when making recommendations regarding the safe 
continuation of the study. The IMM is also provided with reports on safety and enrollment as well as all 
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report is not required. The IMM does not have direct involvement in the conduct of the study. The IMM 
is not responsible for analyzing the primary or secondary outcomes of the study. The IMM’s recommen-
dations need not be based on data provided regarding those outcomes, though he/she may take such data 
into account. However, it is expected that the IMM’s primary recommendations are based on review of 
the raw study data and participant records.  
The DSMB will serve as the sponsor’s medical monitor and will make the final determinations of related-
ness on behalf of the IND sponsor (NINDS). The DSMB will be charged with reviewing all safety and 
efficacy data at a twice-yearly meeting. This meeting may take place in person, as a teleconference, or via 
email. The DSMB may be consulted in person and as needed to discuss clinical issues. The DSMB will 
operate under the rules of an approved charter that will be reviewed during the first DSMB meeting. After 
the twice-yearly interim meetings, the DSMB chair will provide a report to the study PI and NINDS Office 
of the Clinical Director. 
10.6.1 Independent Hepatology Assessment Committee (HAC) 
An expert committee of independent hepatologists will review all cases of potential DILI and will provide 
guidance on case evaluation and risk mitigation. The Hepatology Assessment Committee recommenda-
tions will be made available to the DSMB. Details of the responsibilities of the Independent Hepatology 
Assessment Committee and its workflow will be described in a separate charter. 
 
10.7 QUALITY ASSURANCE AND QUALITY CONTROL 
The clinical site will perform internal quality management of study conduct, data and biological specimen 
collection, documentation and completion. An individualized quality management plan will be developed 
to describe a site’s quality management. A Contract Research Organization (CRO) will perform quality 
assurance monitoring for this study. This study will be monitored in accord with the NINDS Monitoring 
SOP. 
Following written Standard Operating Procedures (SOPs), the monitors will verify that the clinical trial is 
conducted and data are generated and biological specimens are collected, documented (recorded), and 
reported in compliance with the protocol, International Conference on Harmonisation Good Clinical Prac-
tice (ICH GCP), and applicable regulatory requirements (e.g., Good Laboratory Practices (GLP), Good 
Manufacturing Practices (GMP)). 
The investigational site will provide direct access to all trial related sites, source data/documents, and 
reports for the purpose of monitoring and auditing by the sponsor, and inspection by local and regulatory 
authorities. 
A Contract Research Organization (CRO) will provide on-site monitoring of this protocol. The study team, 
the Sponsor and the CRO monitor will determine the frequency of monitoring visits, which will be de-
scribed in the QA Monitoring Plan. The frequency of visits will include, at a minimum, annual monitoring 
visits until the protocol has undergone a close-out visit, unless otherwise indicated by the Sponsor. The 
Sponsor, via the CRO, will be responsible for providing adequate oversight of the investigation to ensure 
adequate protection of the rights, welfare, and safety of human subjects and the quality and integrity of 
the resulting data. 
10.8 DATA HANDLING AND RECORD KEEPING 
10.8.1 Data Collection and Management Responsibilities 
Data collection is the responsibility of the clinical trial staff at the site under the supervision of the site 
investigator. The investigator is responsible for ensuring the accuracy, completeness, legibility, and time-
liness of the data reported. 
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data. 
Study visit worksheets will be provided for use as source document worksheets for recording data for each 
participant enrolled in the study. Data recorded in the electronic case report form (eCRF) derived from 
source documents should be consistent with the data recorded on the source documents. 
Clinical data (including adverse events (AEs), concomitant medications, and expected adverse reactions 
data) and clinical laboratory data will be entered into CRIS, a 21 CFR Part 11-compliant data capture 
system provided by the NIH Clinical Center. The data system includes password protection and internal 
quality checks, such as automatic range checks, to identify data that appear inconsistent, incomplete, or 
inaccurate. Clinical data will be entered directly from the source documents. 
10.8.2 Study Records Retention 
Study documents should be retained for a minimum of 2 years after the last approval of a marketing ap-
plication in an International Conference on Harmonisation (ICH) region and until there are no pending or 
contemplated marketing applications in an ICH region or until at least 2 years have elapsed since the 
formal discontinuation of clinical development of the study intervention, and as per the NIH Intramural 
Records Retention Schedule. No records will be destroyed without the written consent of the sponsor, if 
applicable. It is the responsibility of the sponsor to inform the investigator when these documents no longer 
need to be retained. 
10.9 PROTOCOL DEVIATIONS AND NON-COMPLIANCE 
It is the responsibility of the investigator to use continuous vigilance to identify and report deviations to 
the NIH Institutional Review Board as per Policy 801 and per NINDS Event Reporting SOP. The investi-
gator is responsible for knowing and adhering to the reviewing IRB requirements. 
10.9.1 NIH Definition of Protocol Deviation 
A protocol deviation is any changed, divergence, or departure from the IRB-approved research protocol. 
• 
Major deviations: Deviations from the IRB approved protocol that have, or may have the po-
tential to, negatively impact the rights, welfare or safety of the subject, or to substantially neg-
atively impact the scientific integrity or validity of the study. 
• 
Minor deviations: Deviations that do not have the potential to negatively impact the rights, 
safety or welfare of subjects or others, or the scientific integrity or validity of the study. 
10.10 PUBLICATION AND DATA SHARING POLICY 
10.10.1Human Data Sharing Plan 
This study will be conducted in accordance with the following publication and data sharing policies and 
regulations: 
NIH Public Access Policy, which ensures that the public has access to the published results of NIH funded 
research. It requires scientists to submit final peer-reviewed journal manuscripts that arise from NIH funds 
to the digital archive PubMed Central upon acceptance for publication. 
This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH- Funded 
Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. 
As such, this trial will be registered at ClinicalTrials.gov, and results information from this trial will be 
submitted to ClinicalTrials.gov. In addition, every attempt will be made to publish results in peer-reviewed 
journals. De-identified study data may be shared with data repositories as described below. Furthermore, 
applicable (e.g., generated via the NIH Clinical Center Clinical Research Information System [CRIS]) 
identified data may be shared via the NIH Biomedical Translational Research Information System 
(BTRIS) following standard NIH Clinical Center operating procedures, including BTRIS data access pol-
icies. Data may be shared before the time of publication. Finally, data from this study may be requested 

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from other researchers up to 2 years after the completion of the primary endpoint by contacting the Prin-
cipal Investigator. 
The following specific provisions apply to this protocol: 
Sharing of identified samples and data. Identified samples and data obtained under this protocol, in par-
ticipants who are also enrolled in other research protocols at NIH or outside NIH, may be shared with 
those protocols’ investigators. This sharing will enable pooling of often-scarce resources and will also 
reduce demands on participants’ time and effort. Provisions for sharing of identified samples and data in 
this fashion are included in the consent form for this protocol. Required institutional approval, including 
materials/data transfer and collaboration agreements, will apply in all cases. Materials/data will be 
shipped/transferred in accordance with NIH and federal regulations.  
Sharing of coded and unlinked samples and data. Samples and data will be stripped of identifiers and may 
be coded (“de-identified”) or unlinked from an identifying code (“anonymized”). Coded samples and/or 
data may be shared; the key to the code will not be provided to collaborators but will remain at NIH. 
Submission to non-NIH sponsored or supported databases and repositories will be submitted for prospec-
tive IRB approval. Required approvals from the collaborating institution will be obtained and materials 
will be shipped in accordance with NIH and federal regulations. 
Fellows, students, or other trainees in the investigators’ labs may work with coded samples and data while 
at NIH and after leaving NIH, if needed to complete a project or prepare data for publication. Those who 
have left NIH and who are not associate investigators on this study will not have access to identifying 
information or to the key to the data code. Departing fellows, students, and trainees will sign an agreement 
with NINDS requiring that coded study data will be maintained on password-protected computers, used 
only for the specified purposes of the protocol, not shared, and destroyed once the project is completed. 
Before sharing identifiable data with departing investigators, all necessary agreements will be obtained. 
10.10.2Genomic Data Sharing Plan  
Not applicable. 
10.11 COLLABORATIVE AGREEMENTS 
10.11.1Agreement Type 
This study is performed under a Cooperative Research and Development Agreement (CRADA) with 
Sanofi-Genzyme. 
10.12 CONFLICT OF INTEREST POLICY 
The independence of this study from any actual or perceived influence, such as by the pharmaceutical 
industry, is critical. Therefore, any actual conflict of interest of persons who have a role in the design, 
conduct, analysis, publication, or any aspect of this trial will be disclosed and managed. Furthermore, 
persons who have a perceived conflict of interest will be required to have such conflicts managed in a way 
that is appropriate to their participation in the design and conduct of this trial. The study leadership, in 
conjunction with the NINDS, has established policies and procedures for all study group members to dis-
close all conflicts of interest and will establish a mechanism for the management of all reported dualities 
of interest. 
11 ABBREVIATIONS 
 
9HPT 
9-Hole Peg Test 
AE 
Adverse Event 
AESI 
Adverse Event of Special Interest 
BBB 
Blood-Brain Barrier 

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BRaKe-MS 
BRuton’s tyrosine KinasE in Multiple Sclerosis 
BTK 
Bruton’s Tyrosine Kinase 
BTRIS 
Biomedical Translational Research Information System 
CD 
Cluster of Differentiation 
CFR 
Code of Federal Regulations 
CLIA 
Clinical Laboratory Improvement Amendments 
CMP 
Clinical Monitoring Plan 
CNS 
Central Nervous System 
COC 
Certificate of Confidentiality 
CONSORT 
Consolidated Standards of Reporting Trials 
CFR 
Code of Federal Regulations 
CRF 
Case Report Form 
CRIS 
Clinical Research Information System 
CRO 
Contract Research Organization 
CSF 
Cerebrospinal Fluid 
CSSRS 
Columbia Suicide Severity Rating Scale 
DSMB 
Data and Safety Monitoring Board 
DCC 
Data Coordinating Center 
DHHS 
Department of Health and Human Services 
DILI 
Drug-Induced Liver Injury 
DPA 
Durable Power of Attorney 
DSMB 
Data Safety Monitoring Board 
DRE 
Disease-Related Event 
EAE 
Experimental Autoimmune Encephalomyelitis 
EC 
Ethics Committee 
ECG 
Electrocardiogram 
eCRF 
Electronic Case Report Forms 
EDSS 
Expanded Disability Status Scale 
ELISA 
Enzyme-Linked Immunosorbent Assay 
FDA 
Food and Drug Administration 
FDAAA 
Food and Drug Administration Amendments Act of 2007 
FFR 
Federal Financial Report 
GCP 
Good Clinical Practice 
GLP 
Good Laboratory Practices 
gMG 
Generalized Myasthenia Gravis 
GMP 
Good Manufacturing Practices 
GWAS 
Genome-Wide Association Studies 
HAC 
Hepatology Assessment Committee  
HIPAA 
Health Insurance Portability and Accountability Act 
IB 
Investigator’s Brochure 
ICH 
International Conference on Harmonisation 
ICMJE 
International Committee of Medical Journal Editors 
IDE 
Investigational Device Exemption 
IMM 
Independent Medical Monitor 
IMP 
Investigational Medicinal Product 

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IND 
Investigational New Drug Application 
IRB 
Institutional Review Board 
ISM 
Independent Safety Monitor 
ISO 
International Organization for Standardization 
ITT 
Intention-To-Treat 
IV 
Intravenous 
LLN 
Lower Limit of Normal 
LOAEL 
Lower Adverse Event Effect Level 
LSMEANS 
Least-squares Means 
MAD 
Multiple Ascending Dose 
MAI 
Medical Advisory Investigator 
MedDRA 
Medical Dictionary for Regulatory Activities 
MOP 
Manual of Procedures 
MRI 
Magnetic Resonance Imaging 
MS 
Multiple Sclerosis 
MSDS 
Material Safety Data Sheet 
NCT 
National Clinical Trial 
NIH 
National Institutes of Health 
NIH IC 
NIH Institute or Center 
NIMP 
Non-Investigational Medical Product 
NINDS 
National Institute of Neurological Disorders and Stroke 
NOAEL 
No Adverse Event Effect Level 
nr-SPMS 
Nonrelapsing Secondary Progressive Multiple Sclerosis  
NSAID 
Non-Steroidal Anti-Inflammatory Drug 
OHRP 
Office for Human Research Protections 
PASAT 
Paced Auditory Serial Addition Test 
PBMC 
Peripheral Blood Mononuclear Cell 
PCSA 
Potentially Clinically Significant Abnormality 
PI 
Principal Investigator 
PK 
Pharmacokinetic 
PML 
Progressive Multifocal Leukoencephalopathy 
PPMS 
Primary Progressive Multiple Sclerosis  
QA 
Quality Assurance 
QC 
Quality Control 
QTcF 
QT Interval corrected using Fridericia’s formula 
RMS 
Relapsing Multiple Sclerosis  
RNA 
Ribonucleic Acid 
SAD 
Single Ascending Dose 
SAE 
Serious Adverse Event 
SAP 
Statistical Analysis Plan 
SDMT 
Symbol Digit Modalities Test 
SOA 
Schedule of Activities 
SOC 
System Organ Class 
SOP 
Standard Operating Procedure 
T 
Tesla 

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T25W 
Timed 25-foot Walk 
TUG 
Timed Up-and-Go 
ULN 
Upper Limit of Normal 
UP 
Unanticipated Problem 
US 
United States 
 
 
 

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12 APPENDIX 
12.1 APPENDIX 1: MEDICATIONS THAT CANNOT BE TAKEN WITH TOLEBRUTINIB 
Certain medications cannot be taken while taking tolebrutinib. These include strong CYP3A inducers or 
CYP2C8 inhibitors or anticoagulant/antiplatelet therapies. Antacids can be used. Please see below for a list 
or medications that cannot be taken with tolebrutinib. 
 
Strong CYP3A Inducers or CYP2C8 Inhibitors 
Generic name 
Brand name 
Therapeutic class 
metamizole (dipyrone) 
Novalgin 
Analgesics 
apalutamide 
Erleada 
Antiandrogens  
enzalutamide 
Xtandi 
Antiandrogens  
rifampicin 
Rifampin 
Antibiotics  
rifapentine 
Priftin 
Antibiotics  
rifabutin 
Mycobutin 
Antibiotics  
nafcillin 
Nallpen, Unipen 
Antibiotics  
phenytoin 
Dilantin 
Anticonvulsants  
carbamazepine 
Tegretol 
Anticonvulsants  
phenobarbital 
Luminal Sodium, Solfoton 
Anticonvulsants  
cenobamate 
Xcopri, Ontozry 
Anticonvulsants  
telotristat ethyl 
Xermelo 
Antidiarrheals 
lesinurad 
Zurampic 
Antigout and uricosuric agents 
mitotane 
Lysodren 
Antineoplastics  
thioridazine 
Mellaril  
Antipsychotics  
asunaprevir/beclabuvir/ 
daclatasvir  
Daklinza 
Antivirals  
ivosidenib 
Tibsovo 
Cancer treatments 
lumacaftor 
Orkambi  
Cystic fibrosis treatments 
bosentan 
Tracleer 
Endothelin receptor antagonists  
gemfibrozil 
Lopid 
Fibric acid derivatives 
elagolix 
Orilissa 
Gonadotropin-releasing hormone 
antagonist 
St John's wort extract 
 
Herbal medications  
dabrafenib 
Tafinlar 
Kinase inhibitors  
lorlatinib 
Lorbrena  
Kinase inhibitors  

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pexidartinib 
Turalio 
Kinase inhibitors  
efavirenz 
Sustiva 
Non-nucleoside reverse transcrip-
tase inhibitors (NNRTIs) 
etravirine 
Intelence 
Non-nucleoside reverse transcrip-
tase inhibitors (NNRTIs) 
lopinavir/ritonavir 
Kaletra 
Protease inhibitors 
tipranavir / ritonavir 
Aptivus 
Protease inhibitors  
 
 
 
 
CYP3A4 Inhibitors 
boceprevir 
cobicistat  
danoprevir and ritonavir  
elvitegravir and ritonavir  
grapefruit juice  
indinavir and ritonavir  
itraconazole  
ketoconazole 
lopinavir and ritonavir  
paritaprevir and ritonavir and 
(ombitasvir and/or dasabuvir)  
posaconazole 
ritonavir  
saquinavir and ritonavir  
telaprevir 
tipranavir and ritonavir 
telithromycin 
troleandomycin 
voriconazole 
clarithromycin 
idelalisib 
nefazodone 
nelfinavir 
 
 
 
Anticoagulant/Antiplatelet Therapies 
Acetylsalicylic acid (aspirin) 
Antiplatelet drugs (e.g., clopidogrel) 
Vitamin K antagonist (warfarin) 
Antithrombin agents 
(heparin, including low molecular weight heparin) 
Direct thrombin inhibitor (dabigatran) 
Direct factor Xa inhibitors (apixaban, edoxaban, rivaroxaban) 
 
Note: All above drugs need to be stopped at least 5 half-lives before study drug administration except for 
aspirin, which needs to be stopped at least 8 days before. 
 
 

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12.2 APPENDIX 2: Adverse Events of Special Interest (AESI) 
  
DILI Assessment Algorithm: 
 
In ANY CASE REQUIRING HAC REPORTING, INFORM the PI, HAC and Sponsor and follow the 
instructions below: 
 
• 
INVESTIGATE specifically for malaise with or without loss of consciousness, dizziness, and/or 
hypotension and/or episode of arrhythmia in the previous 72 hours; rule out muscular injury 
• 
EVALUATE for alternative causes 
• 
CONSULT with a hepatologist 
• 
PERFORM the following tests: 
o LFTs: AST, ALT, alkaline phosphatase, total and conjugated bilirubin, GGT and pro-
thrombin time/ INR 
o CPK, serum creatinine, complete blood count 
o Anti-HAV lgM, anti-HBc lgM, HBsAg, (HBV-DNA if clinically indicated), anti-HCV 
and HCV RNA, and anti-HEV lgM antibodies 
o Auto-antibodies: antinuclear, ANCA, anti-dsDNA, anti-smooth muscle, anti-LKM, anti-
mitochondrial 
o Hepatobiliary ultrasonography (or other imaging and/or biopsy investigations if needed) 
• 
DEPENDING on the clinical context, check for recent infection with EBV, CMV, herpes viruses, 
and toxoplasma 
• 
CONSIDER iron, ferritin, transferrin saturation 
• 
CONSIDER, DNA test for Gilbert's disease if clinically indicated 
• 
CONSIDER patient hospitalization if INR>2 (or PT<50%) and/or central nervous system disturb-
ances suggesting hepatic encephalopathy  
• 
MONITOR transaminases and total bilirubin levels as closely as possible every 48 hours to every 
week until transaminases and/or total bilirubin levels are down-trending, then monitor every 2 

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weeks until 2xULN for transaminases and 1xULN for total bilirubin and then monitor every 
scheduled visit. 
• 
SEND expedited (<15 days) reports to the FDA of any cases with transaminases >8x ULN or >3x 
ULN with total bilirubin >2x ULN. 
 
RECHALLENGE: Re-initiation of the study drug can only be considered after discussion with the HAC, 
PI, DSMB and study Sponsor once the ALT/AST decrease below 2xULN and/or TBL decrease below 
1xULN and there is no clinical contraindication. In case it is agreed to re-start the study drug, ALT, ALT, 
TBL and ALP will be assessed weekly for the 1st month and, then, monthly for the 2nd and the 3rd month. 
The occurrence of new elevations above 3xULN for the ALT/AST values will lead to permanent discon-
tinuation of the study drug. 
 
(Optional) FREEZE serum sample (5ml x 2) 
 
13 REFERENCES 
 
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