Conditions: Amyotrophic Lateral Sclerosis
Keywords: IONIS-SOD1Rx SOD1 ALS
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 176
Healthy volunteers: no

Brief summary:
The primary objectives of Parts A and B of this study are to evaluate the safety, tolerability, and pharmacokinetics (PK) of ascending doses of tofersen in adults with ALS and a documented superoxide dismutase 1 (SOD1) mutation. The primary objective of Part C of this study is to evaluate the clinical efficacy of tofersen administered to adults with ALS and a confirmed SOD1 mutation.

The secondary objective of Parts A and B of this study is to evaluate the effects of tofersen on levels of total SOD1 protein in the cerebrospinal fluid (CSF). The secondary objectives of Part C are to evaluate the safety, tolerability, pharmacodynamic (PD), and biomarker effects of tofersen.

Detailed description:
This is a 3-part study to examine the efficacy, safety, tolerability, PK, and PD of tofersen. Part A is the single ascending dose (SAD) component of the study, Part B is the multiple ascending dose (MAD) component of study and Part C is the fixed dose component of the study. Hence, the overall phase of development of the study is 1/2/3.

The study completed on 16 Jul 2021. In total, the study enrolled 176 participants, of which 108 enrolled in Part C.

Arms:
arm 1: Participants will be administered tofersen-matching placebo once by intrathecal bolus injection on Day 1 of Cohorts 1, 2, 3, and 4 respectively. arm 2: Participants will be administered tofersen 10 mg once by intrathecal bolus injection on Day 1. arm 3: Participants will be administered tofersen 20 mg once by intrathecal bolus injection on Day 1 of Cohort 2 after the safety review of Cohort 1. arm 4: Participants will be administered tofersen 40 mg once by intrathecal bolus injection on Day 1 of Cohort 3 after the safety review of Cohort 2. arm 5: Participants will be administered tofersen 60 mg once by intrathecal bolus injection on Day 1 of Cohort 4 after the safety review of Cohort 3. arm 6: Participants will be administered tofersen-matching placebo, 3 loading doses once every 2 weeks on Days 1, 15, 29 and 2 maintenance doses once every 4 weeks on Days 57 and 85 by intrathecal injection. arm 7: Participants will be administered tofersen 20 mg, 3 loading doses once every 2 weeks on Days 1, 15, 29 and 2 maintenance doses once every 4 weeks on Days 57 and 85 by intrathecal injection. arm 8: Participants will be administered tofersen 40 mg, 3 loading doses once every 2 weeks on Days 1, 15, 29 and 2 maintenance doses once every 4 weeks on Days 57 and 85 by intrathecal injection after the safety and PK review of Cohort 5. arm 9: Participants will be administered tofersen 60 mg, 3 loading doses once every 2 weeks on Days 1, 15, 29 and 2 maintenance doses once every 4 weeks on Days 57 and 85 by intrathecal injection after the safety, PK review and SOD1 PD review of Cohort 6. arm 10: Participants will be administered tofersen 100 mg, 3 loading doses once every 2 weeks on Days 1, 15, 29 and 2 maintenance doses once every 4 weeks on Days 57 and 85 by intrathecal injection after the safety, PK review and SOD1 PD review of Cohort 7. arm 11: Participants will be administered tofersen-matching placebo, 3 loading doses administered once every 2 weeks on Days 1, 15, 29 followed by 5 maintenance doses administered once every 4 weeks on Days 57, 85, 113, 141, 169 up to 24 weeks by intrathecal bolus injection. arm 12: Participants will be administered tofersen 100 mg, 3 loading doses administered once every 2 weeks on Days 1, 15, 29 followed by 5 maintenance doses administered once every 4 weeks on Days 57, 85, 113, 141, 169 up to 24 weeks by intrathecal bolus injection.

Interventions: intervention 1: Tofersen intervention 2: Placebo
Intervention descriptions: intervention 1: Administered as specified in the treatment arm. intervention 2: Administered as specified in the treatment arm.

Protocol document:
Prot_000.pdf: 




Protocol 233AS101
Version 8
Phase 1/2/3 Study of BIIB067 in Adults with ALS
CONFIDENTIAL
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc.
3
TABLE OF CONTENTS
TABLE OF CONTENTS.................................................................................................................3
LIST OF TABLES.........................................................................................................................10
LIST OF FIGURES .......................................................................................................................10
1.
SPONSOR INFORMATION .....................................................................................11
2.
LIST OF ABBREVIATIONS.....................................................................................12
3.
SYNOPSIS .................................................................................................................15
4.
STUDY SCHEMATIC AND SCHEDULE OF ACTIVITIES FOR 
STUDY 233AS101.....................................................................................................22
4.1.
Study Schematic .........................................................................................................23
4.2.
Schedule of Activities.................................................................................................26
5.
INTRODUCTION......................................................................................................39
5.1.
Overview of Amyotrophic Lateral Sclerosis..............................................................39
5.2.
Current Therapies for Amyotrophic Lateral Sclerosis................................................39
5.3.
Profile of Previous Experience with BIIB067............................................................39
5.3.1.
Nonclinical Experience...............................................................................................39
5.3.1.1.
Toxicology..................................................................................................................40
5.3.1.2.
Pharmacokinetics........................................................................................................40
5.3.2.
Clinical Experience.....................................................................................................41
5.4.
Study Rationale...........................................................................................................41
5.5.
Rationale for Dosing Regimen ...................................................................................42
6.
STUDY OBJECTIVES AND ENDPOINTS..............................................................44
6.1.
Parts A (SAD) and B (MAD) .....................................................................................44
6.1.1.
Primary Objective.......................................................................................................44
6.1.1.1.
Primary Endpoints ......................................................................................................44
6.1.2.
Secondary Objective...................................................................................................44
6.1.2.1.
Secondary Endpoint....................................................................................................44
6.1.3.
Exploratory Objectives and Endpoints.......................................................................44
6.2.
Part C (Pivotal) ...........................................................................................................45
6.2.1.
Primary Objective.......................................................................................................45
6.2.1.1.
Primary Efficacy Endpoint .........................................................................................45
6.2.1.2.
Secondary Efficacy Endpoints....................................................................................45


Protocol 233AS101
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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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45
6.2.2.
Secondary Objective...................................................................................................45
6.2.2.1.
Safety/Tolerability Endpoint ......................................................................................45
6.2.2.2.
Pharmacodynamic Endpoint.......................................................................................45
6.2.2.3.
Biomarker Endpoint....................................................................................................46
46
6.2.3.1.
Pharmacokinetic Endpoints ........................................................................................46
46
46
7.
STUDY DESIGN .......................................................................................................47
7.1.
Study Overview ..........................................................................................................47
7.1.1.
Part A: SAD Evaluation..............................................................................................47
7.1.2.
Part B: MAD Evaluation ............................................................................................48
7.1.2.1.
Parts A and B..............................................................................................................48
7.1.3.
Part C: Pivotal.............................................................................................................48
7.2.
Study Specifics ...........................................................................................................49
7.2.1.
Dose Escalation ..........................................................................................................49
7.2.1.1.
Part A: Single Ascending Dose ..................................................................................49
7.2.1.2.
Part B: Multiple Ascending Dose...............................................................................50
7.2.2.
Within Cohort Staggered Dosing................................................................................52
7.2.2.1.
Part A: Single Ascending Dose ..................................................................................52
7.2.2.2.
Part B: Multiple Ascending Dose...............................................................................52
7.2.2.3.
Part C ..........................................................................................................................53
7.2.3.
Dose-Limiting Toxicity ..............................................................................................53
7.3.
Overall Study Duration and Follow-Up .....................................................................53
7.3.1.
Screening ....................................................................................................................53
7.3.1.1.
Part A: Single Ascending Dose ..................................................................................53
7.3.1.2.
Part B: Multiple Ascending Dose...............................................................................53
7.3.1.3.
Part C ..........................................................................................................................54
7.3.2.
Dosing.........................................................................................................................54
7.3.2.1.
Part A: Single Ascending Dose ..................................................................................54
7.3.2.2.
Part B: Multiple Ascending Dose...............................................................................54


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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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7.3.2.3.
Part C: Pivotal.............................................................................................................54
7.3.3.
Follow-Up Procedures................................................................................................54
7.3.3.1.
Part A: Single Ascending Dose ..................................................................................54
7.3.3.2.
Part B: Multiple Ascending Dose...............................................................................54
7.3.3.3.
Part C: Pivotal.............................................................................................................55
7.4.
Study Stopping Rules .................................................................................................55
7.4.1.
Dose Suspension (Parts A and B only).......................................................................55
7.4.2.
Dose Termination .......................................................................................................56
7.4.2.1.
Parts A and B..............................................................................................................56
7.4.2.2.
Part C ..........................................................................................................................56
7.5.
End of Study ...............................................................................................................56
8.
SELECTION OF PARTICIPANTS ...........................................................................57
8.1.
Parts A (SAD) and B (MAD) .....................................................................................57
8.1.1.
Inclusion Criteria ........................................................................................................57
8.1.2.
Exclusion Criteria.......................................................................................................58
8.2.
Part C (Pivotal) ...........................................................................................................59
8.2.1.
Inclusion Criteria ........................................................................................................59
8.2.2.
Exclusion Criteria.......................................................................................................60
9.
ENROLLMENT, REGISTRATION, AND RANDOMIZATION ............................63
9.1.
Screening and Enrollment...........................................................................................63
9.2.
Randomization and Registration of Participants ........................................................63
9.3.
Blinding Procedures....................................................................................................64
10.
DISCONTINUATION OF STUDY TREATMENT OR WITHDRAWAL 
OF PARTICIPANTS FROM THE STUDY...............................................................65
10.1.
Withdrawal from the Study (Part A) or Discontinuation of Study Treatment 
(Parts B and C)............................................................................................................65
11.
STUDY TREATMENT USE .....................................................................................66
11.1.
Regimen......................................................................................................................66
11.1.1.
BIIB067 ......................................................................................................................66
11.1.2.
Placebo........................................................................................................................66
11.2.
Modification of Dose and/or Treatment Schedule......................................................66
11.3.
Concomitant Therapy and Procedures........................................................................67
11.3.1.
Concomitant Therapy .................................................................................................67


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11.3.1.1.
Allowed Concomitant Therapy...................................................................................67
11.3.1.2.
Disallowed Concomitant Therapy..............................................................................67
11.3.2.
Concomitant Procedures.............................................................................................68
12.
STUDY TREATMENT MANAGEMENT................................................................69
12.1.
BIIB067 ......................................................................................................................69
12.1.1.
BIIB067 Preparation...................................................................................................69
12.1.2.
BIIB067 Storage.........................................................................................................69
12.1.3.
BIIB067 Handling and Disposal.................................................................................70
12.1.4.
BIIB067 Accountability..............................................................................................70
12.2.
Placebo Product ..........................................................................................................70
13.
CLINICAL FUNCTION, PHARMACOKINETIC, AND 
PHARMACODYNAMIC ASSESSMENTS..............................................................71
13.1.
Assessments of the Effect of BIIB067 on Clinical Function......................................71
13.1.1.
ALS Functional Rating Scale-Revised.......................................................................71
13.1.2.
Slow Vital Capacity....................................................................................................71
13.1.3.
Participant Diary/eDiary (Part C only).......................................................................71
71
72
13.1.6.
Handheld Dynamometry.............................................................................................72
72
72
72
73
73
73
73
13.2.
Pharmacokinetic Assessments....................................................................................74
13.3.
Pharmacodynamic Assessments.................................................................................74
74
75
14.
SAFETY ASSESSMENTS ........................................................................................76
14.1.
Clinical Safety Assessments.......................................................................................76


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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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14.2.
Laboratory Safety Assessments..................................................................................76
77
15.
SAFETY DEFINITIONS, RECORDING, REPORTING, AND 
RESPONSIBILITIES .................................................................................................78
15.1.
Definitions ..................................................................................................................78
15.1.1.
Adverse Event.............................................................................................................78
15.1.2.
Serious Adverse Event................................................................................................78
15.1.3.
Prescheduled or Elective Procedures or Routinely Scheduled Treatments................79
15.2.
Safety Classifications..................................................................................................79
15.2.1.
Investigator Assessment of Events.............................................................................79
15.2.2.
Relationship of Events to Study Treatment................................................................80
15.2.3.
Severity of Events.......................................................................................................80
15.2.4.
Expectedness of Events ..............................................................................................81
15.3.
Monitoring and Recording Events..............................................................................81
15.3.1.
Adverse Events...........................................................................................................81
15.3.2.
Serious Adverse Events..............................................................................................81
15.3.3.
Immediate Reporting of Serious Adverse Events.......................................................81
15.3.3.1.
Deaths .........................................................................................................................82
15.3.4.
Suspected Unexpected Serious Adverse Reactions....................................................82
15.4.
Procedures for Handling Special Situations ...............................................................82
15.4.1.
Pregnancy ...................................................................................................................82
15.4.2.
Overdose.....................................................................................................................83
15.4.3.
Medical Emergency....................................................................................................83
15.4.3.1.
Unblinding for Medical Emergency...........................................................................83
15.5.
Contraception Requirements ......................................................................................83
15.6.
Safety Responsibilities................................................................................................84
15.6.1.
The Investigator..........................................................................................................84
15.6.2.
Biogen.........................................................................................................................85
16.
STATISTICAL METHODS AND DETERMINATION OF SAMPLE SIZE...........86
16.1.
Part A (SAD) and Part B (MAD) ...............................................................................86
16.1.1.
Clinical Function ........................................................................................................86
16.1.1.1.
Analysis Population....................................................................................................86


Protocol 233AS101
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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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16.1.1.2.
Methods of Analysis...................................................................................................86
16.1.2.
Pharmacokinetics........................................................................................................86
16.1.2.1.
Analysis Population....................................................................................................86
16.1.2.2.
Methods of Analysis...................................................................................................86
16.1.3.
Pharmacodynamics.....................................................................................................86
16.1.3.1.
Analysis Population....................................................................................................86
16.1.3.2.
Methods of Analysis...................................................................................................87
16.1.4.
Biomarker and Pharmacogenomic Analyses..............................................................87
16.1.4.1.
Analysis Population....................................................................................................87
16.1.4.2.
Methods of Analysis...................................................................................................87
16.1.5.
Safety..........................................................................................................................87
16.1.5.1.
Analysis Population....................................................................................................87
16.1.5.2.
Methods of Analysis...................................................................................................87
88
88
88
88
16.1.8.
Sample Size Considerations .......................................................................................89
16.2.
Part C ..........................................................................................................................89
16.2.1.
Clinical Function ........................................................................................................89
16.2.1.1.
Analysis Population....................................................................................................89
16.2.1.2.
Methods of Analysis...................................................................................................89
16.2.2.
Pharmacokinetics........................................................................................................93
16.2.2.1.
Analysis Population....................................................................................................93
16.2.2.2.
Methods of Analysis...................................................................................................93
16.2.3.
Pharmacodynamics.....................................................................................................93
16.2.3.1.
Analysis Population....................................................................................................93
16.2.3.2.
Methods of Analysis...................................................................................................93
16.2.4.
Safety..........................................................................................................................94
16.2.4.1.
Analysis Population....................................................................................................94
16.2.4.2.
Methods of Analysis...................................................................................................94
95


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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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95
95
95
95
17.
ETHICAL REQUIREMENTS ...................................................................................97
17.1.
Declaration of Helsinki...............................................................................................97
17.2.
Ethics Committee........................................................................................................97
17.3.
Participant Information and Consent..........................................................................97
17.4.
Participant Data Protection.........................................................................................98
17.5.
Compensation for Injury.............................................................................................98
17.6.
Conflict of Interest......................................................................................................98
17.7.
Registration of Study and Disclosure of Study Results..............................................98
18.
ADMINISTRATIVE PROCEDURES.......................................................................99
18.1.
Study Site Initiation....................................................................................................99
18.2.
Quality Assurance.......................................................................................................99
18.3.
Monitoring of the Study..............................................................................................99
18.4.
Study Funding.............................................................................................................99
18.5.
Publications.................................................................................................................99
19.
FURTHER REQUIREMENTS AND GENERAL INFORMATION......................100
19.1.
Public Health Emergencies.......................................................................................100
19.2.
External Contract Organizations...............................................................................101
19.2.1.
Contract Research Organization...............................................................................101
19.2.2.
Interactive Response Technology.............................................................................101
19.2.3.
Electronic Data Capture............................................................................................101
19.2.4.
Laboratory Assessments...........................................................................................101
19.3.
Study Committees.....................................................................................................102
19.3.1.
Safety Surveillance Team.........................................................................................102
19.3.2.
Independent Data Monitoring Committee................................................................102
19.3.3.
Endpoint Adjudication Committee...........................................................................102
19.4.
Changes to Final Study Protocol ..............................................................................102
19.5.
Ethics Committee Notification of Study Completion or Termination......................102
19.6.
Retention of Study Data............................................................................................102


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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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19.7.
Study Report Signatory.............................................................................................103
20.
REFERENCES .........................................................................................................104
21.
SIGNED AGREEMENT OF THE STUDY PROTOCOL.......................................106
APPENDIX A.
CONTINUOUS REASSESSMENT METHOD .............................................107
LIST OF TABLES
Table 1:
Schedule of Activities: Part A – Single Ascending Dose...........................................26
Table 2:
Schedule of Activities: Part B – Multiple Ascending Dose .......................................29
Table 3:
Schedule of Activities: Part C (Pivotal)......................................................................33
LIST OF FIGURES
Figure 1:
Study Design: Part A – Single Ascending Dose.........................................................23
Figure 2:
Study Design: Part B – Multiple Ascending Dose .....................................................24
Figure 3:
Study Design: Part C (Pivotal) ...................................................................................25
Figure 4:
Dose Escalation Schematic (Parts A and B)...............................................................51


Protocol 233AS101
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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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1.
SPONSOR INFORMATION
Biogen MA Inc. is the Sponsor of the study. 
Biogen MA Inc.
225 Binney Street
Cambridge, MA  02142
United States
Biogen Idec Research Limited
Innovation House
70 Norden Road
Maidenhead, Berkshire 
SL6 4AY
United Kingdom
Biogen Japan Ltd.
Nihonbashi 1-chome 
Mitsui Building 14F
4-1 Nihonbashi 1-chome
Chuo-ku, Tokyo
103-0027 Japan
For urgent medical issues in which the study’s Medical Director should be contacted, please 
refer to the Study Reference Guide’s Official Study Contact List for complete contact 
information.
Biogen may transfer any or all of its study-related responsibilities to a contract research 
organization and other third parties; however, Biogen retains overall accountability for these 
activities.


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2.
LIST OF ABBREVIATIONS
Ab
antibody
AE
adverse event
ALS
amyotrophic lateral sclerosis
ALSFRS-R
Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised
ANCOVA
analysis of covariance
anti-HBc
total hepatitis B core antibody
anti-HBs
hepatitis B surface antibody
APTT
activated partial thromboplastin time
ASO
antisense oligonucleotide
AUC
area under the concentration-time curve
CNS
central nervous system
CRF
case report form
CRM
continuous reassessment method
CSF
cerebrospinal fluid
C-SSRS
Columbia Suicide Severity Rating Scale
CTCAE
Common Terminology Criteria for Adverse Events
DHA
Directions for Handling and Administration
DLT
dose-limiting toxicity
DNA
deoxyribonucleic acid
DPS
diaphragm pacing system
EAC
event adjudication committee
ECG
electrocardiogram
EEG
electroencephalogram
EOS
end of study
FIH
first-in-human
FSH
follicle-stimulating hormone
FU
follow-up
FVC
forced vital capacity
GCP
Good Clinical Practice
HBsAg
hepatitis B surface antigen
HBV
hepatitis B virus
HCV
hepatitis C virus
HED
human equivalent dose
HHD
handheld dynamometry


Protocol 233AS101
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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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HIV
human immunodeficiency virus
ICF
informed consent form
ICH
International Council for Harmonisation
IDMC
independent data monitoring committee
IgM anti-HBc
immunoglobulin antibody to hepatitis B core antigen
INR
international normalized ratio
IRT
interactive response technology
ITT
intent-to-treat
JRT
joint rank test
LP
lumbar puncture
LTE
long-term extension
MAD
multiple ascending dose
MedDRA
Medical Dictionary for Regulatory Activities
MI
multiple imputation
mITT
modified intent-to-treat
MMSE
Mini-Mental State Examination
mRNA
messenger ribonucleic acid
MTD
maximum tolerated dose
NfL
neurofilament light chain
NHP
nonhuman primate
NOAEL
no observed adverse effect level
PD
pharmacodynamic(s)
PHI
protected health information
PI
principal investigator
PK
pharmacokinetic(s)
pNfH
phosphorylated axonal neurofilament heavy chain
PT
prothrombin time
RNA
ribonucleic acid
SAD
single ascending dose
SAE
serious adverse event
SD
standard deviation
SOD1
superoxide dismutase 1
SUSAR
suspected unexpected serious adverse reaction
SVC
slow vital capacity
t½
elimination half-life
TEAE
treatment-emergent adverse event
V
visit


Protocol 233AS101
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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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Protocol 233AS101
Version 8
Phase 1/2/3 Study of BIIB067 in Adults with ALS
CONFIDENTIAL
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc.
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3.
SYNOPSIS
Protocol Number:
233AS101
Protocol Title:
A Study to Evaluate the Efficacy, Safety, Tolerability, 
Pharmacokinetics, and Pharmacodynamics of BIIB067 
Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation
Version Number
8
Name of Study Treatment:
BIIB067
Study Indication:
Amyotrophic lateral sclerosis and confirmed superoxide 
dismutase 1 mutation
Study Rationale
ALS is a rare neurodegenerative disease resulting in loss of 
motor neurons within the cortex, brainstem, and spinal cord. 
Patients suffer gradual loss of muscle mass, strength, and 
function in bulbar, respiratory, and voluntary muscle. 
Decline is inevitable, with death from respiratory failure 
following 2 to 5 years after diagnosis for most patients. 
Although the majority of patients suffer from sporadic ALS, 
a smaller fraction of patients, approximately 2%, have an 
inherited, or familial, form of ALS caused by a variety of 
mutations in SOD1 (SOD1-ALS). Since SOD1-ALS was 
first described in 1993, over 180 SOD1 mutations have been 
reported to cause this form of ALS. Although the 
mechanism by which mutations cause SOD1-ALS is not 
known, data suggest that toxic gain of function, not loss of 
SOD1 activity, is the likely trigger that initiates the cascade 
of events resulting in motor neuron death. 
The only currently approved treatments for ALS are riluzole 
and edaravone. Riluzole provides a modest increase in 
survival (2 to 3 months) without noticeable improvement in 
strength or disability. Edaravone lessens functional decline 
as measured by ALSFRS-R. The effect of edaravone on 
survival is unknown. No specific SOD1-ALS treatments are 
available. Reducing SOD1 mRNA and, subsequently, toxic 
SOD1 protein may offer therapeutic benefit for SOD1-ALS 
participants. Delivery of an ASO targeting SOD1 mRNA is 
a viable method to reduce toxic SOD1 protein.


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BIIB067 is an investigational ASO inhibitor of SOD1 
mRNA, under development to reduce levels of SOD1 
protein in patients with SOD1-ALS.
Phase of Development:
1/2/3
Study Objectives and 
Endpoints:
Parts A (SAD) and B (MAD)
The primary objective of Parts A and B of this study is to 
evaluate the safety, tolerability, and PK of BIIB067 in adults 
with ALS and a confirmed SOD1 mutation.
The primary endpoints are as follows:

Incidence of AEs and SAEs

Incidence of abnormalities in clinical laboratory 
assessments, vital signs, physical and 
neurological examinations, and ECGs

PK measures, including plasma and CSF levels 
of BIIB067
The secondary objective is to evaluate the effects of 
BIIB067 on levels of total SOD1 protein in the CSF.

The secondary endpoint is the change from 
baseline in CSF levels of total SOD1 protein.
Exploratory objectives and endpoints are listed in 
Section 6.1.
Part C (Pivotal)
Primary Objective
The primary objective of Part C of this study is to evaluate 
the clinical efficacy of BIIB067 administered to adult 
participants with ALS and a confirmed SOD1 mutation.

Primary Efficacy Endpoint
The primary efficacy endpoint is the change from 
baseline to Week 28 in the ALSFRS-R total score.


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
Secondary Efficacy Endpoints
The secondary efficacy endpoints are as follows:

Change from baseline to Week 28 in SVC

Changes from baseline to Week 28 in HHD 
megascore to assess muscle strength, as 
measured by the HHD device

Time to death or permanent ventilation 
(≥ 22 hours of mechanical ventilation [invasive 
or noninvasive] per day for ≥ 21 consecutive 
days)

Time to death
Secondary Objective
The secondary objective is to evaluate the safety, 
tolerability, PD, and biomarker effects of BIIB067 
administered to adult participants with ALS and a confirmed 
SOD1 mutation.

Safety/Tolerability Endpoint
The safety/tolerability endpoint is the incidence of 
AEs and SAEs.

Pharmacodynamic Endpoint
The PD endpoint is the change from baseline in total 
SOD1 protein concentration in CSF.

Biomarker Endpoint
The biomarker endpoint is the change from baseline 
in NfL concentration in plasma.
Exploratory objectives and endpoints are listed in 
Section 6.2.
Study Design:
This is a randomized, double-blind, placebo-controlled, 
3-part dose escalation study to examine the efficacy, safety, 
tolerability, PK, and PD of BIIB067, administered by 
intrathecal bolus injection to up to approximately 183 adult 
participants with ALS and a confirmed SOD1 mutation. 
Part A (SAD)
Part A will be a randomized, double-blind, 
placebo-controlled, SAD study of up to 4 dose levels of 
BIIB067 administered to participants with SOD1-ALS. The 
dose levels will be evaluated sequentially. Final sample size 


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for Part A will be determined by the incidence of DLT. If no 
DLTs are encountered, a minimum of 20 participants will be 
randomized. The maximum sample size for Part A is 
36 participants. 
Part B (MAD)
Part B will be a randomized, double-blind, 
placebo-controlled, MAD evaluation of up to 4 dose levels 
of BIIB067 administered up to 5 times to approximately 
48 participants with SOD1-ALS. 
Part C (Pivotal)
Part C will be a randomized, double-blind, 
placebo-controlled evaluation of 100 mg of BIIB067 
administered 8 times over approximately 24 weeks to 
approximately 99 participants with SOD1-ALS. Participants 
will be randomized to receive BIIB067 or placebo in a 2:1 
(active:placebo) ratio. The primary analysis population 
(N = ~60) will comprise participants who meet prognostic 
enrichment criteria for rapid disease progression, defined as 
those with a prerandomization ALSFRS-R slope decline of 
at least 0.9/month OR a protocol-defined SOD1 mutation 
and prerandomization ALSFRS-R slope decline of at least 
0.2/month.
Randomization will be stratified by 3 factors: 

whether a participant meets the prognostic 
enrichment criteria for rapid disease progression 

whether a participant uses edaravone at baseline

whether a participant uses riluzole at baseline

Use of both edaravone and riluzole will not 
be a separate stratum but will be classified as 
only edaravone use.
Study Location:
Approximately 42 sites are planned in approximately 
15 countries globally.
Number of Planned 
Participants:
Approximately 183 participants are planned to be dosed: 
36 participants in Part A, 48 participants in Part B, and 
99 participants in Part C.
Study Population:
This study will be conducted in participants who are at least 
18 years of age with SOD1-ALS.
Detailed criteria are described in Section 8.


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Treatment Groups:
Cohorts 1 through 4 (Part A) and Cohorts 5 through 8 
(Part B) will be randomized to receive BIIB067 or placebo 
in a 3:1 (active:placebo) ratio. Cohort 9 (Part C) will be 
randomized to receive BIIB067 or placebo in a 2:1 
(active:placebo) ratio.
Part A (SAD)
Up to 4 cohorts will be enrolled in Part A (SAD). Cohorts 
1 through 3 will enroll at least 4 participants each: 
1 participant will be administered placebo, and 
3 participants will be administered BIIB067 at 10, 20, or 
40 mg. Cohort 4 will enroll approximately 8 participants: 
2 participants will be administered placebo, and 
6 participants will be administered BIIB067 at 60 mg. Up to 
16 additional participants may be enrolled into any of the 
cohorts (up to 4 placebo and up to 12 BIIB067), based on 
the incidence of DLT. If no DLTs are observed in the 
2 lower dose cohorts, then participants within these 2 lower 
dose cohorts may re-enroll, after a washout period of at least 
5 times the t½ [~20 weeks including the 8-week FU period], 
within the 2 higher dose cohorts. These participants will 
repeat the screening assessments prior to re-enrolling and 
will be rerandomized into either the BIIB067 or placebo 
group.
Part B (MAD)
Up to 4 cohorts will be enrolled in Part B (MAD). Each 
cohort will enroll approximately 12 participants: 
3 participants per cohort will be administered placebo, and 
9 participants per cohort will be administered BIIB067 at 
20, 40, 60, or 100 mg. 
Part C (Pivotal) 
A single cohort of approximately 99 participants will be 
enrolled in Part C (Pivotal): approximately 33 participants 
will be administered placebo, and approximately 
66 participants will be administered BIIB067 at 100 mg. 


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Duration of Treatment and 
Follow-Up:
Part A (SAD)
Duration of the study for each participant participating only 
in Part A (SAD) will be up to approximately 15 weeks, 
which will include up to 7-week screening period and an 
8-week FU period. For participants who choose to re-enroll 
in a higher dose cohort, the total duration will be 
approximately 35 weeks, which will include a washout 
period of 3 × t½ (~12 weeks) after the 8-week postdose FU 
visit (total washout of 5 × t½, or ~20 weeks). 
Part B (MAD)
For participants participating in only Part B (MAD), the 
duration will be up to approximately 31 weeks, which will 
include up to 7-week screening period, a 12-week treatment 
period (consisting of 3 loading doses of BIIB067, 
administered approximately once every 2 weeks, followed 
by 2 maintenance doses of BIIB067, administered 
approximately once every 4 weeks), and a 12-week FU 
period.
Part A (SAD) and Part B (MAD)
For participants participating in both Part A (SAD) and 
Part B (MAD), duration will be approximately 51 weeks. 
This will include 15 weeks in Part A, approximately 
12 weeks between the end of Part A and dosing in Part B, 
12 weeks of dosing in Part B, and the 12-week FU period in 
Part B. For participants who enroll in 2 cohorts during 
Part A and participate in Part B, the total duration will be 
approximately 71 weeks. 
Part C (Pivotal)
For participants in Part C (Pivotal), the study duration will 
be approximately 32-36 weeks including a 4-week screening 
period, a 24-week treatment period (3 loading doses 2 weeks 
apart followed by 5 maintenance doses 4 weeks apart), and a 
4- to 8-week FU period as follows:

Part C participants who enroll (uninterrupted) in 
the LTE study (233AS102): Week 28 Visit will 
serve as EOS Visit

Part C participants with delays between their 
Week 28 Visit and enrollment in the LTE study: 
a Safety FU (Alternative EOS) Visit will be 
conducted (either in person or by telephone 
contact) to collect AEs, SAEs, and concomitant 
medications or procedures. This Safety FU 
(Alternative EOS) Visit can be performed at 


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Week 32 or prior to (within 2 days) enrollment in 
the LTE, whichever comes first.

Part C participants who do not enroll in the LTE 
study: Week 32 Visit will serve as EOS (either in 
person or by telephone contact) Visit.
In the event of a decision by the Study Sponsor to terminate 
the study earlier on the grounds that conducting a 
placebo-controlled study is no longer deemed ethical based 
on the assessment of risk-benefit of Study 233AS101, all 
participants will be invited for an EOS visit, during which 
all Week 28 assessments will be conducted. For participants 
not entering the LTE study or in the event the study is 
stopped early, there will be an additional safety FU visit 
8 weeks after the last dose of study treatment.


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Phase 1/2/3 Study of BIIB067 in Adults with ALS
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4.
STUDY SCHEMATIC AND SCHEDULE OF ACTIVITIES FOR 
STUDY 233AS101
Key assessments are included in Figure 1, Figure 2, and Figure 3 for Parts A, B, and C of the 
study, respectively. For a full list of assessments and their timing, please see Table 1, Table 2, 
and Table 3 for Parts A, B, and C, respectively.








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26
4.2.
Schedule of Activities
Table 1:
Schedule of Activities: Part A – Single Ascending Dose
Dosing Inpatient Period
Follow-Up
Screening
Day 1
Tests and Assessments
V11
≤ 21 days 
before V2
V22
Day -28 to 
Day -1
Predose
Dosing/ 
Postdose
Day 2
24 (±1) 
hours 
Postdose
Days 8 & 
29 
(±3 days)
Day 57 (±3 days)/
Early 
Termination 
Visit
Informed Consent (main)
X
X3
Medical History
X
X
Clinical Laboratory Samples to Verify 
Eligibility4
X
FVC
X
Admission to Inpatient Facility
X
Physical Examination
X
X
X5
X5
X5
Weight
X
X
X
Height
X
Neurological Examination
X
X
X6
X
X
X
Vital Signs (temperature, blood pressure, pulse 
rate, respiratory rate)
X
X
X7
X
X
X
12-Lead ECG8
X
X
X7
X
X
X
C-SSRS Questionnaire
X
X9
Urine Pregnancy Test10
X
X
X
FSH Test11
X


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Dosing Inpatient Period
Follow-Up
Screening
Day 1
Tests and Assessments
V11
≤ 21 days 
before V2
V22
Day -28 to 
Day -1
Predose
Dosing/ 
Postdose
Day 2
24 (±1) 
hours 
Postdose
Days 8 & 
29 
(±3 days)
Day 57 (±3 days)/
Early 
Termination 
Visit
Randomization
X
Study Drug Administration
X
SVC
X
X
X
ALSFRS-R
X
X
X
X
HHD
X
X12
X
Clinical Laboratory Samples for Hematology, 
Chemistry, and Urinalysis
X
X
X
X
X
CSF Samples13
X
X14
X
Blood Samples for Plasma anti-BIIB067 Ab
X
X
X
Blood Samples for Biomarkers
X
X12
X
Blood Samples for Plasma PK
X
X16
X
X
X
Discharge from Inpatient Facility
X
AE and Concomitant Therapy and Procedures 
Recording
-------------------------------------------------X (ongoing) ----------------------
------------------
SAE Recording
-------------------------------------------------X (ongoing) -----------------------------


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1 Required only for participants without a prior documentation of SOD1 mutation. Results must be available before performing Screening Visit 2 assessments.
2 Screening assessments can be performed over ~2 days (need not be consecutive) to minimize participant burden.
3 Not required if collected during Screening Visit 1.
4 Including blood samples for HIV, HCV, and HBV tests, and platelet and coagulation tests. Coagulation tests may be repeated at the local laboratory once if, in 
the opinion of the Investigator, values of the initial tests are only slightly out of range. Participants with nonclinically significant and stable out-of-range values 
for coagulation tests may be eligible to enroll in the study at the discretion of the Investigator, and after a consultation with the Sponsor.
5 Limited physical examination will be conducted at the Investigator's discretion.
6 To be assessed at 3 and 6 hours postdose.
7 To be assessed within an hour prior to drawing PK blood samples at 2 and 4 hours postdose.
8 Triplicate 12-lead (paper) ECGs will be obtained after the participant has rested in a supine position for at least 10 minutes. The first ECG will be interpreted, 
and the last 2 will be checked for consistency and quality.
9 Use the “Since Last Visit” version of C-SSRS.
10For women of childbearing potential only.
11To confirm postmenopausal status in postmenopausal female participants.
12Day 29 only.
13LP will be performed to collect CSF samples for PK, PD, safety, and biomarker analysis. The results of the most recent (i.e., obtained at Screening or other 
visit during the study) coagulation tests and platelet count must be reviewed before each LP can be performed. Should the results suggest, in the opinion of the 
Investigator, that an LP may be safely performed, then no further laboratory values need to be reviewed. However, should, in the opinion of the Investigator, 
repeat coagulation and platelet tests be clinically indicated, then these tests may be done locally to facilitate timely review. Results of any repeat tests must be 
available before the LP can be performed.
14To be collected at Day 29 only. Participants will remain under observation in the clinic for approximately 1 hour after the LP procedure and will receive a 
safety FU telephone contact ~24 hours after the procedure.
16To be collected at 1, 2, 4, and 6 hours postdose.


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Table 2:
Schedule of Activities: Part B – Multiple Ascending Dose
Screening
Dosing Inpatient Period
Follow-Up
Day 1
Tests and Assessments
V11
≤ 21 days 
before V2
V22
Day -28 
to Day -1
Predos
e
Dosing/
Postdose
Day 2
24 (±1) 
Postdose
Dosing
Days 15, 
29, 57 & 
85
(±3 days)
Days 83, 
22, 36, 
64, 92, 
and 106
(±3 days)
Days 50 & 
78 
(±3 days) 
via 
Telephone 
Contact
Day 169
(±3 days) 
/Early 
Termination 
Visit
Informed Consent (main)
X
X4
Medical History
X
X
Clinical Laboratory Samples 
to Verify Eligibility5
X
FVC
X
Admission to Inpatient 
Facility
X
Physical Examination
X
X
X6
X6
X6
X6
Weight
X
X
X
Height
X
Limited Neurological 
Examination (including the 
MMSE)7
X
X
X8
X
X9
X
X
Vital Signs (temperature, 
blood pressure, pulse rate, 
respiratory rate)
X
X
X10
X
X11
X
X
12-Lead ECG12
X
X
X10
X
X11
X
X
C-SSRS Questionnaire
X
X13


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Screening
Dosing Inpatient Period
Follow-Up
Day 1
Tests and Assessments
V11
≤ 21 days 
before V2
V22
Day -28 
to Day -1
Predos
e
Dosing/
Postdose
Day 2
24 (±1) 
Postdose
Dosing
Days 15, 
29, 57 & 
85
(±3 days)
Days 83, 
22, 36, 
64, 92, 
and 106
(±3 days)
Days 50 & 
78 
(±3 days) 
via 
Telephone 
Contact
Day 169
(±3 days) 
/Early 
Termination 
Visit
Urine Pregnancy Test14
X
X
X15
X
FSH Test16
X
Randomization
X
Study Drug Administration
X
X
SVC
X
X15
X
ALSFRS-R
X
X
X
X17
X
HHD
X
X17
X
Clinical Laboratory Samples 
for Hematology, 
Coagulation, Chemistry, and 
Urinalysis
X
X
X
X
X
CSF Samples18
X
X19
X20
X


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Screening
Dosing Inpatient Period
Follow-Up
Day 1
Tests and Assessments
V11
≤ 21 days 
before V2
V22
Day -28 
to Day -1
Predos
e
Dosing/
Postdose
Day 2
24 (±1) 
Postdose
Dosing
Days 15, 
29, 57 & 
85
(±3 days)
Days 83, 
22, 36, 
64, 92, 
and 106
(±3 days)
Days 50 & 
78 
(±3 days) 
via 
Telephone 
Contact
Day 169
(±3 days) 
/Early 
Termination 
Visit
Blood Samples for 
Biomarkers
X
X
X22
X
Blood Samples for Plasma 
PK
X
X23
X
X24
X
X
Discharge from Inpatient 
Facility
X
AE, and Concomitant 
Therapy and Procedures 
Recording
-------------------------------------------------X (ongoing) ------------------------------------------
SAE Recording
-------------------------------------------------------------------X (ongoing)------------------------------------------------------------
1 Required only for participants without a prior documentation of SOD1 mutation. Results must be available before performing Screening Visit 2 assessments.
2 Screening assessments can be performed over ~2 days (need not be consecutive) to minimize participant burden.
3 Participants may, at the discretion of the Investigator, have the option of home visits for non-dosing visits that do not require CSF collection or strength and 
electrophysiological measures, which are visits on Days 8, 36, and 64.
4 Not required if collected during Screening Visit 1.
5 Including blood samples for HIV, HCV, and HBV tests, and platelet and coagulation tests. Coagulation tests may be repeated at the local laboratory once if, in 
the opinion of the Investigator, values of the initial tests are only slightly out of range. Participants with nonclinically significant and stable out-of-range values 
for coagulation tests may be eligible to enroll in the study at the discretion of the Investigator, and after a consultation with the Sponsor.


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32
6 Limited physical examination will be conducted at the Investigator's discretion.
7 The components of the limited neurological examination are cranial nerves, coordination/cerebellar function, reflexes, motor, and MMSE.
8 To be assessed at 3 and 6 hours postdose.
9 To be assessed predose, and 3 and 6 hours postdose.
10To be assessed just prior to drawing PK blood samples at 2 and 4 hours postdose.
11To be assessed just prior to drawing PK blood samples at predose, and 2 and 4 hours postdose.
12Triplicate 12-lead (paper) ECGs will be obtained after the participant has rested in a supine position for at least 10 minutes. The first ECG will be interpreted, 
and the last 2 will be checked for consistency and quality.
13Use “Since Last Visit” version of C-SSRS.
14For women of childbearing potential only.
15To be performed predose.
16To confirm postmenopausal status in postmenopausal female participants.
17Day 22 and Day 92 for 
 HHD; Day 92 for ALSFRS-R 
18LP will be performed to collect CSF samples for PK, PD, safety, and biomarker analysis. The results of the most recent (i.e., obtained at Screening or other 
visit during the study) coagulation tests and platelet count must be reviewed before each LP can be performed. Should the results suggest, in the opinion of the 
Investigator, that an LP may be safely performed, then no further laboratory values need to be reviewed. However, should, in the opinion of the Investigator, 
repeat coagulation and platelet tests be clinically indicated, then these tests may be done locally to facilitate timely review. Results of any repeat tests must be 
available before the LP can be performed.
19To be collected predose. Participants will remain under observation in the clinic for approximately 6 hours after the LP procedure and will receive a safety FU 
telephone contact ~24 hours after the procedure.
20To be collected on Day 106 only. Participants will remain under observation in the clinic for approximately 1 hour after the LP procedure and will receive a 
safety FU telephone contact ~24 hours after the procedure.
22Day 106 only.
23To be collected at 1, 2, 4, and 6 hours postdose.
24To be collected predose at each visit; collected at 1, 2, 4, and 6 hours postdose for Day 85 only.


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Table 3:
Schedule of Activities: Part C (Pivotal)
Loading Dose Treatment Period
Maintenance 
Treatment Period
EOS Visit2,3
Safety FU 
(Alternative EOS) 
Visit4
(In Person or 
Telephone Contact) 
Screening1
Baseline
(Dose 1)
Week 2
(Dose 2)
Week 4
(Dose 3)
Week 8, 12, 16, 20, 
and 24
Week 28 OR 
(4 Weeks 
After Last 
Dose)
Week 32 OR
(8 Weeks After Last 
Dose)
Day 1
(±3 days)
Day 15
(±3 days)
Day 29
(±3 days)
Days 57, 85, 113, 
141, and 169 
(±3 days)
Tests and Assessments5
Day
-28 to
Day -1
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days)
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days)
Informed Consent 
(main)6 
X
Medical History
X
Confirmation of 
Eligibility Criteria
X
X
Randomization
X
Telephone Contact7
X
X
X
X
Ventilation Use8,9
X
X
X
X
X
ALSFRS-R8
X
X
X
X
X
X
SVC8,10 
X
X
X
X
X
X
HHD8
X
X
X
X
X


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Loading Dose Treatment Period
Maintenance 
Treatment Period
EOS Visit2,3
Safety FU 
(Alternative EOS) 
Visit4
(In Person or 
Telephone Contact) 
Screening1
Baseline
(Dose 1)
Week 2
(Dose 2)
Week 4
(Dose 3)
Week 8, 12, 16, 20, 
and 24
Week 28 OR 
(4 Weeks 
After Last 
Dose)
Week 32 OR
(8 Weeks After Last 
Dose)
Day 1
(±3 days)
Day 15
(±3 days)
Day 29
(±3 days)
Days 57, 85, 113, 
141, and 169 
(±3 days)
Tests and Assessments5
Day
-28 to
Day -1
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days)
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days)
C-SSRS Questionnaire8
X
X13
X13
X13
Height
X
Weight14
X
X
X
X


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Loading Dose Treatment Period
Maintenance 
Treatment Period
EOS Visit2,3
Safety FU 
(Alternative EOS) 
Visit4
(In Person or 
Telephone Contact) 
Screening1
Baseline
(Dose 1)
Week 2
(Dose 2)
Week 4
(Dose 3)
Week 8, 12, 16, 20, 
and 24
Week 28 OR 
(4 Weeks 
After Last 
Dose)
Week 32 OR
(8 Weeks After Last 
Dose)
Day 1
(±3 days)
Day 15
(±3 days)
Day 29
(±3 days)
Days 57, 85, 113, 
141, and 169 
(±3 days)
Tests and Assessments5
Day
-28 to
Day -1
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days)
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days)
Vital Signs 
(temperature, blood 
pressure, pulse rate, 
respiratory rate)14,15
X
X
X
X
X
X
X
X
X
X
12-Lead ECG14,16
X
X
X17
X11
X17
X
Physical Examination14
X
X
X18
X18
X18
X18
Limited Neurological 
Examination14,19
X
X
X
X
X
X
X
X
X
X
MMSE
X
X
X
X11
X11
X
FSH Test20
X
Pregnancy Test14,21,22
X (serum)
X
X
X
X
X (serum)
Blood Sampling for 
HIV, HCV, and HBV 
Testing
X


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Loading Dose Treatment Period
Maintenance 
Treatment Period
EOS Visit2,3
Safety FU 
(Alternative EOS) 
Visit4
(In Person or 
Telephone Contact) 
Screening1
Baseline
(Dose 1)
Week 2
(Dose 2)
Week 4
(Dose 3)
Week 8, 12, 16, 20, 
and 24
Week 28 OR 
(4 Weeks 
After Last 
Dose)
Week 32 OR
(8 Weeks After Last 
Dose)
Day 1
(±3 days)
Day 15
(±3 days)
Day 29
(±3 days)
Days 57, 85, 113, 
141, and 169 
(±3 days)
Tests and Assessments5
Day
-28 to
Day -1
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days)
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days)
Clinical Laboratory 
Samples for 
Hematology, 
Coagulation, Chemistry, 
and Urinalysis8,23
X
X
X
X
X
X




Protocol 233AS101
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7 Telephone contact to be performed approximately 24 hours after LP.
8 Predose assessments can be performed in a single visit up to 2 days prior to dosing.
9 Participants will use a diary/eDiary to record ventilation use. The diary/eDiary should be completed only for days when the participant uses mechanical 
ventilation. This diary/eDiary will be reviewed with study site staff at each visit.
10If a facemask is used at screening and/or baseline it should be used for all SVC assessments for the duration of the study. If a facemask is not used at screening 
and/or baseline it should not be used for the duration of the study. Upright SVC will be determined by performing 3 to 5 measures. The results will be overread 
by a central reader to confirm that these criteria (at least 3 acceptable tests with the 2 highest acceptable (largest and next largest) efforts within 150 mL of vital 
capacity) have been achieved. 
11To be performed on Week 12 (Day 85) and Week 24 (Day 169) only.
13Use “Since Last Visit” version of C-SSRS.
14Assessment must occur on the day of dosing.
15Temperature, systolic and diastolic blood pressure, pulse rate and respiratory rate will be measured after the participant has rested in a sitting position for at 
least 5 minutes.
16Triplicate 12-lead ECGs will be obtained after the participant has rested in a supine position for at least 10 minutes. All ECGs will be centrally read; ECGs will 
be read by the Investigator at collection and then sent to a central ECG reader for further evaluation and to confirm eligibility at Screening. The first ECG will 
be interpreted, and the last 2 will be checked for consistency and quality.
17To be assessed just prior to drawing PK blood samples at 2, 4, and 6 hours postdose on Day 1 and Day 85 only.
18Limited physical examination will be conducted at the Investigator’s discretion.
19The components of the limited neurological examination include motor, reflexes, and coordination/cerebellar function.
20To confirm postmenopausal status (in postmenopausal female participants only).
21Results from urine or serum pregnancy tests must be reviewed predose in order to determine if dose should be administered or held.
22For women of childbearing potential only. Serum test to be performed at Screening and EOS Visit; urine or serum test to be performed at all other timepoints.
23The results of most recent (i.e., obtained at previous visit) centrally read coagulation tests and platelet count must be reviewed before LP can be performed. 
Coagulation tests may be repeated at local laboratory once if, in the opinion of the Investigator, values of the initial tests are out of range but deemed not 
clinically significant).
24CSF samples collected during the LP procedure will be analyzed to evaluate for blood contamination. CSF samples for safety will be tested at local 
laboratories.
28Participants will remain at the study site for at least 1 hour postdose for safety monitoring and can be discharged at the discretion of the Investigator and in 
compliance with the institutional requirements once the participants have adequately recovered from the dosing procedure.


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5.
INTRODUCTION 
BIIB067 is an investigational second-generation ASO inhibitor of SOD1 mRNA, under 
development to reduce levels of total SOD1 protein in patients with ALS and a confirmed SOD1 
mutation (SOD1-ALS). ASOs are short synthetic strings of nucleotides designed to prevent the 
expression of a targeted protein by selectively binding to the mRNA that encodes the protein 
with high affinity and selectivity through well-characterized Watson-Crick base pairing 
(hybridization).
5.1.
Overview of Amyotrophic Lateral Sclerosis
ALS is a rare neurodegenerative disease resulting in loss of motor neurons within the cortex, 
brainstem, and spinal cord. Patients suffer gradual loss of muscle mass, strength, and function in 
bulbar, respiratory, and voluntary muscle. Decline is inevitable, with death from respiratory 
failure following 2 to 5 years after diagnosis for most patients. Although the majority of patients 
suffer from sporadic ALS, a smaller fraction of patients, approximately 2%, have an inherited, or 
familial, form of ALS caused by a variety of mutations in SOD1. Since SOD1-ALS was first 
described in 1993, over 180 SOD1 mutations have been reported to cause this form of ALS 
(referred to as SOD1-ALS) [ALSoD 2015; Rosen 1993]. Disease progression for individual 
mutations is variable, with survival of less than 15 months seen with the most severe mutations 
[Cudkowicz 1997]. Although the mechanism by which mutations cause SOD1-ALS is not 
known, compelling data suggest that toxic gain of function, not loss of SOD1 activity, is the 
likely trigger that initiates the cascade of events resulting in motor neuron death [Bruijn 1998; 
Rosen 1993]. 
5.2.
Current Therapies for Amyotrophic Lateral Sclerosis
The only currently approved treatments for ALS are riluzole and edaravone. Riluzole provides a 
modest increase in survival (2 to 3 months) without noticeable improvement in strength or 
disability [Miller 2012]. Edaravone lessens functional decline as measured by the ALSFRS-R. 
The effect of edaravone on survival is unknown [Writing Group and Edaravone (MCI-186) ALS 
19 Study Group 2017]. No specific SOD1-ALS treatments are available. 
5.3.
Profile of Previous Experience with BIIB067
5.3.1.
Nonclinical Experience
Four in vivo nonclinical toxicology studies were performed to support the development of 
BIIB067: a repeated-dose, 12-week, subcutaneous bolus injection study in mice (25 and 
150 mg/kg); a single-dose, intrathecal bolus injection study in rats (0.1, 0.3, 1.0, and 3.0 mg); a 
repeated-dose, 13-week, intrathecal bolus injection study in cynomolgus monkeys (4, 12, and 
35 mg); and a repeated-dose, 9-month, intrathecal bolus injection study in cynomolgus monkeys 
(4, 12, and 35 mg). 
See the Investigator’s Brochure for detailed information on nonclinical studies.


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5.3.1.1.
Toxicology
In mice, subcutaneous administration of BIIB067 was well tolerated, with the highest dose 
evaluated (150 mg/kg) being the NOAEL. The NOAELs in the toxicology studies in which the 
clinical route of administration (intrathecal) was used were 1 mg (rat) and 35 mg (monkey). 
In rats, a single intrathecal bolus delivery of BIIB067 resulted in 1 early death in a rat receiving 
the highest dose evaluated (3 mg). Transient acute tactile hypersensitivity was noted 
approximately 25 minutes postdose in animals receiving 3 mg. Decreases in arousal, gait, 
mobility, respiration and sensorimotor observations were also noted 3 hours postdose in the 3-mg 
group.
In cynomolgus monkeys, repeated intrathecal administration of BIIB067 for 13 weeks was well 
tolerated up to the highest dose evaluated (35 mg); although, 2 animals in the 35-mg group had 
transient clinical signs (reduced locomotor activity). Cytoplasmic vacuolation in some neurons of 
the hippocampus, and to a lesser degree of the cerebral cortex, was observed at all doses (4, 12, 
and 35 mg). The neuronal vacuolation was not associated with any morphological evidence of 
cell degeneration or necrosis, and was fully reversible within a 13-week recovery period. 
Furthermore, intrathecal injection of BIIB067 caused mononuclear inflammatory cell infiltrates 
in the meninges at the lumbar spinal cord injection site, possibly as a local proinflammatory 
effect caused by ribonuclease H-based ASOs. Remnants of such inflammatory infiltrates were 
still detectable after 13 weeks of recovery, although at a lower magnitude. In addition, 
vacuolated histiocytes were found in lymph nodes as well as in the Virchow-Robin space of the 
brain; this finding was not fully reversible within 13 weeks. Neuronal vacuolation in the spinal 
cord was observed in 1 recovery animal, which was not observed in any animal at the end of the 
13-week dosing period. The relationship of this finding to BIIB067 is unknown. Based on the 
lack of any evidence of cell degeneration or necrosis, and absence of clinical or neurological 
abnormalities associated with the vacuolation, it was concluded that the microscopic findings are 
not adverse. 
From the 9-month cynomolgus monkey toxicology study, the NOAEL for repeated, 
intrathecally-administered BIIB067 was 12 mg. This was based on adverse clinical observations 
for 1 female administered 35 mg. This female exhibited neurological signs after the second dose, 
characterized by transient muscle cramping (seen immediately after dosing on multiple days), 
prolonged recovery from anesthesia, and intermittent tremors (during the last months of the 
dosing phase). Treatment with diazepam was required on several dosing occasions. An EEG on 
this animal revealed altered postdose signals (with effects on high frequency bands) but 
confirmed that muscle cramping during EEG recording was not a seizure and could have been 
related to arousal. This finding was considered test-article related; however, there were no 
correlates in clinical and anatomic pathology. 
5.3.1.2.
Pharmacokinetics
To characterize the PK properties of BIIB067, CSF [monkey only], plasma (monkey and mouse 
only), and tissue (monkey, mouse, and rat) concentrations were assessed following intrathecal 
(monkey and rat) or subcutaneous (mouse) administration. 
Following bolus intrathecal administration in monkeys, BIIB067 concentrations in CSF declined 
in a multiphasic manner with a rapid distribution phase, followed by a slower and longer 


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elimination phase. The rapid distribution phase was due to rapid and broad distribution from CSF 
to CNS tissues and clearance from CSF due to transfer to systemic circulation (including plasma 
and systemic tissues such as kidney and liver). The estimated CSF t½ was 20 to 37 days. 
BIIB067 concentrations in plasma peaked 1 to 4 hours after the intrathecal bolus injection in 
monkeys and then rapidly declined during the first 48 hours postdose, with a much slower 
elimination phase thereafter. The estimated plasma t½ was 22 to 51 days. In mice, BIIB067 
concentrations in plasma peaked 0.5 hour after subcutaneous administration, indicating rapid 
absorption into the systemic circulation and, then similar to monkeys, declined rapidly over the 
next 48 hours due to extensive distribution to systemic tissues. 
Dose-dependent tissue distribution of BIIB067 to CNS and peripheral tissues was seen in all 
species studied (monkey, rat, and mouse), with no clear or consistent evidence of a sex 
difference in distribution to tissues. 
Following intrathecal administration, distribution to CNS tissues was broad in both rats and 
monkeys, with the highest CNS concentrations seen in the lumbar spinal cord, consistent with 
the intrathecal route of administration. In monkeys, relatively higher concentrations were 
observed in the liver and kidney, indicating a significant proportion of the administered dose was 
distributed from CSF to the systemic circulation. During the recovery period, BIIB067 appeared 
to be cleared slowly from CNS and peripheral tissues. The estimated tissue t½ was similar to CSF 
and plasma (31 to 40 days in CNS tissues, 15 to 20 days in the liver, and 18 to 23 days in the 
kidney). BIIB067 was rapidly and extensively distributed from plasma to liver and kidney 
following subcutaneous administration in mice. 
The long CSF and CNS tissue t½ observed in monkeys support an infrequent clinical dosing 
regimen following intrathecal administration.
5.3.2.
Clinical Experience
This is the FIH study of BIIB067. In the single and multiple dose escalation parts (Parts A and 
B) of this study, BIIB067 at dose levels up to and including 100 mg was generally well tolerated. 
Most of the AEs were mild or moderate in severity. Plasma concentrations of BIIB067 were dose 
proportional; CSF concentrations showed a less than dose proportional response. A statistically 
significant reduction in total CSF SOD1 protein concentration was observed in the BIIB067 
100 mg group (37% reduction) compared with the placebo group (no reduction). Interim 
exploratory analyses showed a slowing of decline in functional (ASLFRS-R), respiratory (SVC), 
and strength measures (HHD Megascore). These data support the continued development of 
BIIB067 for the treatment of SOD1-ALS.
5.4.
Study Rationale
BIIB067 is an investigational ASO inhibitor of SOD1 mRNA, under development to reduce 
levels of SOD1 protein in patients with SOD1-ALS.
Overexpression of mutant SOD1 in mice or rats recapitulates important aspects of ALS in 
humans [Bruijn and Cleveland 1996; Gurney 1994]; however, loss of SOD1, while resulting in 
eventual motor neuron dysfunction, does not result in motor neuron death [Fischer 2012; 
Reaume 1996]. Furthermore, neither loss nor increase of SOD1 activity in mouse models of 


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SOD1-ALS alters survival [Bruijn 1998]. In humans, individual disease mutations are associated 
with varying levels of SOD1 activity; some patients with disease-causing mutations have 
apparently normal SOD1 activity [Saccon 2013]. Thus, correlation between disease severity and 
normal SOD1 activity has not been observed [Andersen 1997; Ratovitski 1999; Saccon 2013]. In 
contrast, reduction of SOD1 with intracerebroventricular-delivered SOD1 ASO extends survival 
in a rodent model of SOD1-ALS [Smith 2006]. These observations strongly suggest that 
SOD1-ALS is caused by toxic properties of the mutant SOD1 protein. Reducing SOD1 mRNA 
and, subsequently, toxic SOD1 protein may offer therapeutic benefit for patients with 
SOD1-ALS. Intrathecal delivery of an ASO targeting SOD1 mRNA is a viable method to reduce 
toxic SOD1 protein.
Parts A (SAD) and B (MAD)
Pharmacology and toxicology data in rats, mice, and monkeys indicate that BIIB067 is well 
tolerated. Parts A and B of the study will evaluate the safety, tolerability, and PK profile of a 
range of single and multiple intrathecal BIIB067 doses from a projected minimal pharmacologic 
dose to either the MTD or the highest planned dose of 100 mg. MTD for this study is defined as 
the highest tested dose with a less than 33% DLT rate at Day 15. See Section 7.2.3 for the 
definition of DLT.
Part C (Pivotal)
Based on the interim data from Parts A and B summarized in Section 5.3.2, a randomized, 
double-blind, placebo-controlled, pivotal phase (Part C) has been designed to assess the efficacy 
and safety of BIIB067 100 mg versus placebo. Approximately 99 participants with SOD1-ALS 
will be randomized to receive BIIB067 or placebo and treated for 24 weeks.
5.5.
Rationale for Dosing Regimen
BIIB067 will be administered via intrathecal bolus at single ascending doses to cohorts in Part A, 
and at multiple ascending doses to cohorts in Part B.
The BIIB067 dosing regimens for Parts A and B of this study were selected based on nonclinical 
toxicology and PK observations in NHP studies using repeated-dosing intrathecal administration 
for 13 weeks and 9 months, and target tissue concentrations from SOD1 transgenic mouse 
models. 
Based on pharmacology and PK results in SOD1 transgenic mice, the estimated tissue 
concentrations of BIIB067 needed to produce a 50%, and the upper 95% confidence interval of 
an 80%, SOD1 mRNA reduction within the human spinal cord are 0.9 µg/g and 4.7 µg/g, 
respectively. Evaluations of cortex from the same experiment indicate that the estimated tissue 
concentration of BIIB067 needed to produce a 50% cortical SOD1 mRNA reduction is 8 µg/g.
The lowest dose selected for this study (10 mg in Part A) is predicted to achieve greater than 
0.9 µg/g tissue concentration in the spinal cord. The initial highest proposed dose (60 mg, 
multiple dose in Part B) was predicted to achieve greater than 4.7 µg/g steady-state tissue 
concentration in the spinal cord, and approximately 1.5 µg/g steady-state tissue concentration in 
the cortex, which is expected to yield approximately 15% to 20% SOD1 mRNA reduction in that 
tissue. The addition of a 100-mg cohort is predicted to achieve steady-state exposures in the 
cortex of approximately 2.5 µg/g, which is predicted to be sufficient for a meaningful reduction 


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in total CSF SOD1 protein of 25% to 30%. This reduction is expected to be clinically 
meaningful, based on the expectation that the reduction of SOD1 protein in tissues (spinal cord 
and cortex) would be greater than the 20% to 30% reduction observed in CSF. This prediction is 
based on observations in NHP studies, where approximately 50% reduction in CSF corresponded 
to approximately 50% or greater reduction in the spinal cord and cortex. In rodent efficacy 
experiments, doses of BIIB067 that reduced tissue total SOD1 protein by approximately 30% or 
more were found to improve measures of electrophysiology, function, and neurofilament.
Based on nonclinical PK and pharmacology data, and taking into consideration participant 
safety, the inconvenience of repeated intrathecal injections, and the rapid, fatal nature of ALS, 
the following dose intervals were selected for Part B of the study (MAD): 3 loading doses, once 
every 2 weeks, and 2 maintenance doses, administered once every 4 weeks. These intervals were 
selected based on the estimated t½ of BIIB067 (~1 month) in the target CNS tissues (spinal cord 
and brain cortex), to achieve and maintain the target tissue concentration of BIIB067 at a steady 
state level and within the estimated pharmacologically active range, and to facilitate effective 
total SOD1 protein reduction in the CSF within Part B of the study (MAD). 
From the 9-month NHP toxicology study, the NOAEL for repeated, intrathecally-administered 
BIIB067 was 12 mg. This NOAEL was converted to an HED based on the NHP to human CSF 
volume scaling (approximately 10-fold difference). CSF volume scaling conservatively estimates 
the needed scaling factor and has predicted HED with reasonable accuracy. The HED for the 
9-month, intrathecal NHP toxicology study was calculated to be 120 mg. This provides a 12-fold 
safety margin for the BIIB067 starting dose (10 mg), and a 2-fold safety margin for the 60-mg 
dose. The safety margin for a 100-mg clinical dose (highest planned dose) would be 1.2-fold. 
Preliminary PK data (AUC from time 0 to 24 hours) from the 20-mg MAD cohort indicate that 
the safety margin based on exposure is 2.2-fold relative to a 100-mg clinical dose. The 1.2-fold 
safety margin based on CSF volume scaling from the NHP toxicology study was chosen over the 
2.2-fold safety margin calculated from the plasma steady-state exposures since the former 
provides a more conservative estimate.
Therefore, all BIIB067 doses planned for 233AS101 are predicted to be pharmacologically 
active, while maintaining sufficient safety margins calculated from the 9-month intrathecal NHP 
toxicology study. 
For Part C (Pivotal), the dose of 100 mg of BIIB067 was determined based on the interim 
analyses of data from participants in Part B (MAD) Cohorts 5 to 8 treated for 85 days. Safety 
analyses of these data suggested that all doses through 100 mg had been well tolerated with a 
safety profile supportive of continued development of BIIB067 in ALS participants. The 
selection of the 100 mg BIIB067 dose for Part C is supported by PK/PD and exploratory efficacy 
analyses of data from participants in Part A (SAD) and Part B (MAD) [see Section 5.3.2].


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6.
STUDY OBJECTIVES AND ENDPOINTS
6.1.
Parts A (SAD) and B (MAD)
6.1.1.
Primary Objective 
The primary objective of Parts A and B of this study is to evaluate the safety, tolerability, and PK 
of BIIB067 in adult participants with ALS and a confirmed SOD1 mutation.
6.1.1.1.
Primary Endpoints
The primary endpoints are as follows:

Incidence of AEs and SAEs.

Incidence of abnormalities in clinical laboratory assessments, vital signs, physical and 
neurological examinations, and ECGs.

PK measures, including plasma and CSF levels of BIIB067.
6.1.2.
Secondary Objective
The secondary objective is to evaluate the effects of BIIB067 on levels of total SOD1 protein in 
the CSF. 
6.1.2.1.
Secondary Endpoint
The secondary endpoint is the change from baseline in CSF levels of total SOD1 protein.
6.1.3.
Exploratory Objectives and Endpoints
To evaluate the effect of BIIB067 on 
 HHD.

The endpoints that relate to this objective are the changes from baseline in 
 
 HHD scores.
To evaluate the effect of BIIB067 on measures of clinical function.

The endpoints that relate to this objective are changes from baseline in the following 
measures: 

ALSFRS-R scores

SVC






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7.
STUDY DESIGN
7.1.
Study Overview
This is a randomized, double-blind, placebo-controlled, 3-part study to examine the efficacy, 
safety, tolerability, PK, and PD of BIIB067, administered by intrathecal bolus injection to up to 
approximately 183 participants with ALS and a confirmed SOD1 mutation. Parts A and B are 
single and multiple dose escalating parts, respectively, in which participants will be randomized 
to receive BIIB067 or placebo in a 3:1 (active:placebo) ratio. In Part C, participants will be 
randomized to receive BIIB067 100 mg or placebo in a 2:1 (active:placebo) ratio. The study will 
be conducted at approximately 42 sites in approximately 15 countries globally. See Figure 1, 
Figure 2, and Figure 3 for Parts A, B, and C of the study, respectively. 
7.1.1.
Part A: SAD Evaluation
Part A will be a randomized, double-blind, placebo-controlled, SAD study of up to 4 dose levels 
of BIIB067 administered to participants with SOD1-ALS. The dose levels will be evaluated 
sequentially. Final sample size for Part A of the study will be determined by the incidence of 
DLT. If no DLTs are encountered, a minimum of 20 participants will be randomized. The 
maximum sample size for Part A is 36 participants. The first 3 dose levels will be assessed in 
cohorts of 4 participants each: 1 participant will be administered placebo, and 3 participants will 
be administered BIIB067 at 10, 20, or 40 mg. The last dose level will be assessed in a cohort of 
8 participants: 2 participants will be administered placebo, and 6 participants will be 
administered BIIB067 at 60 mg. Up to 16 additional participants may be enrolled into the 
selected dose levels (4 administered placebo and 12 administered BIIB067), based on the 
incidence of DLT. See Section 7.2.1 for a detailed description of dose escalation.
If no DLTs are observed in the 2 lower dose cohorts, then participants within these 2 lower dose 
cohorts may re-enroll, after a washout period of at least 5 times the t½ (~20-week; including the 
8-week FU period), within the 2 higher dose cohorts. These participants will repeat the screening 
assessments prior to re-enrolling, and will be rerandomized into either the BIIB067 or placebo 
group.
The duration of study participation for each participant enrolled in Part A will be up to 
approximately 15 weeks, which will include up to 7-week screening period and an 8-week FU 
period. For participants who choose to re-enroll in a higher dose cohort, the total duration will be 
approximately 35 weeks, which will include a washout period of 3 times the t½ (~12 weeks) after 
the 8-week FU visit (total washout of 5 times the t½, or ~20 weeks). Participants who re-enroll in 
a higher cohort will repeat Screening Visit 2 assessments, which can occur during the washout 
period.
The SAD portion of the study will be completed when any one of the following criteria is met. 

MTD or the highest planned dose has been given to up to 9 active participants.

A maximum of 36 participants have been enrolled.


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7.1.2.
Part B: MAD Evaluation
Part B will be a randomized, double-blind, placebo-controlled, MAD evaluation of up to 4 dose 
levels of BIIB067 administered up to 5 times, over approximately 3 months, approximately 
48 participants with SOD1-ALS. Each dose level will be assessed in cohorts of 12 participants: 
3 participants will be administered placebo, and 9 participants will be administered BIIB067 at 
20, 40, 60, or 100 mg. 
The duration of study participation for each participant enrolled in Part B will be up to 
approximately 31 weeks, which will include up to 7-week screening period, a 12-week treatment 
period (consisting of 3 loading doses of BIIB067, administered approximately once every 
2 weeks, followed by 2 maintenance doses of BIIB067, administered approximately once every 
4 weeks), and a 12-week FU period.
7.1.2.1.
Parts A and B
Participants with SOD1-ALS who participate in Part A (SAD) of the study will be able to re-
enroll in Part B (MAD), after a washout period of at least 3 times the t½ (~12-week), at a dose 
level that is either the same or at the next level up from the dose received in Part A (for 
participants who choose to re-enroll, this will be the last dose level received in Part A). For 
participants participating in both the SAD and the MAD portion of the study, duration will be 
approximately 51 weeks (71 weeks for participants who enroll in 2 cohorts during Part A). This 
will include all Part A visits, a period of at least 3 times the t½ (~12 weeks) between the 8-week 
FU visit of Part A and the first dosing visit of Part B (~20-week total washout), and all Part B 
visits, excluding the Part B screening period, which can occur during the washout period, within 
28 days before Day 1. 
7.1.3.
Part C: Pivotal
Part C will be a randomized, double-blind, placebo-controlled evaluation of 100 mg of BIIB067 
administered 8 times over approximately 24 weeks to approximately 99 participants with 
SOD1-ALS.
Part C: Screening-Only Sites
Some sites may be designated as screening-only sites and will only perform screening visit 
assessments. Participants who complete screening at screening-only sites and are deemed eligible 
for participation in Part C will be transferred to a full participation site for the remainder of the 
study. Participants may also be screened at full treatment sites and transferred to other full 
treatment sites for randomization.
Part C: Full Participation Sites
Randomization will occur only at full participation sites. It is planned to randomize 
approximately 99 participants total, of whom approximately 60 participants will meet the 
protocol-defined prognostic enrichment criteria for rapid disease progression (see Section 8.2.1). 


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Randomization will be stratified by the following 3 factors:

whether a participant meets the prognostic enrichment criteria for rapid disease 
progression 

whether a participant uses edaravone at baseline

whether a participant uses riluzole at baseline

Use of both edaravone and riluzole will not be a separate stratum but will be 
classified as edaravone use. 
For participants in Part C (Pivotal), the study duration will be approximately 32-36 weeks 
including a 4-week screening period, a 24-week treatment period (3 loading doses 2 weeks apart 
followed by 5 maintenance doses 4 weeks apart), and a 4- to 8-week FU period as follows:

Part C participants who enroll (uninterrupted) in the LTE study (233AS102): 
Week 28 Visit will serve as EOS Visit

Part C participants with delays between their Week 28 Visit and enrollment in the 
LTE study: a Safety FU (Alternative EOS) Visit will be conducted (either in person 
or by telephone contact) to collect AEs, SAEs, and concomitant medications or 
procedures. This Safety FU (Alternative EOS) Visit can be performed at Week 32 or 
prior to (within 2 days) enrollment in the LTE, whichever comes first.

Part C participants who do not enroll in the LTE study: Week 32 Visit will serve as 
EOS Visit (either in person or by telephone contact)
In the event of a decision by the Sponsor to terminate the study earlier on the grounds that 
conducting a placebo-controlled study is no longer deemed ethical based on the assessment of 
risk-benefit of Study 233AS101, all participants will be invited for an EOS Visit, during which 
all Week 28 assessments will be conducted. For participants not entering the LTE study or in the 
event the study is stopped early, there will be an additional safety FU visit 8 weeks after the last 
dose of study treatment.
7.2.
Study Specifics
7.2.1.
Dose Escalation
7.2.1.1.
Part A: Single Ascending Dose
The dose levels will be evaluated sequentially. After the 14-day safety review for the last 
participant within a cohort is completed (Day 15), and prior to dosing of the next cohort (the next 
planned dose level), a Biogen Medical Director and a Global Safety and Regulatory Sciences: 
Global Safety Physician will review participants’ available blinded safety data with the PI. These 
data include AEs and SAEs, vital signs, physical and neurological examinations, ECGs, and 
clinical laboratory safety tests. Review of blinded safety data may be followed by review of 
unblinded safety data of the current cohort and all available safety data from preceding cohorts 
by the Biogen Medical Director, Global Safety Physicians, Biostatistician, Clinical 
Pharmacologist, and, if required, any ad hoc members. Before escalating to the next higher dose 
level, there must be agreement that the current emerging safety and tolerability data support dose 


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escalation. Progression to each subsequent dose level will be based on the number of DLTs, as 
defined in Section 7.2.3, observed in participants treated with BIIB067. For each dose level, if 
any DLT is observed, then the Biogen Medical Director, Global Safety Physician, Biostatistician, 
Clinical Pharmacologist, and, if required, any ad hoc members will review the safety profile, 
integrating results from the CRM [see Appendix A], to decide dose expansion, escalation, or de-
escalation. A maximum of 12 participants can be dosed at each dose level. In general, the 
occurrence of DLTs in at least 3 out of 9 participants treated with BIIB067 in a cohort 
(i.e., ≥ 33.3% DLT rate) will result in the cohort being considered dose limiting. In this situation, 
the prior dose may be considered the MTD. The prior cohort may be expanded, if necessary, to 
confirm there is an acceptable toxicity profile at the lower dose prior to its designation as the 
MTD. 
See Figure 4 for a dose escalation schematic.
7.2.1.2.
Part B: Multiple Ascending Dose
After a minimum of 10 participants within a cohort complete the Day 106 FU Visit (~3 weeks 
after last dose), and prior to dosing of the next, higher dose cohort, a Biogen Medical Director 
and a Global Safety Physician will review all available blinded safety data with the PI. Review 
of blinded safety data may be followed by review of unblinded safety data of the current cohort 
and all available safety data from preceding cohorts by the Biogen Medical Director, Global 
Safety Physician, Biostatistician, Clinical Pharmacologist, and, if required, any ad hoc members. 
In addition to review of the safety data, a Biogen Medical Director, Clinical Pharmacologist, and, 
if required, any ad hoc members will review PK data through the trough levels after the fourth 
dose (samples collected predose on Day 85) for a minimum of 6 dosed participants within a 
cohort, prior to dosing of the next, higher dose cohort. Before escalating to the next, higher dose 
level, there must be agreement that the current emerging safety, tolerability, and PK data support 
dose escalation. The progression to each subsequent dose level will be based on the number of 
DLTs observed in participants treated with BIIB067. Prior to continuing to the 60-mg and 
100-mg dose cohorts, available CSF of the previous cohorts will be assessed to determine the 
level of total SOD1 protein reduction. Based on this total SOD1 protein level data, the decision 
will be made to proceed with the planned dosing regimen, to alter the dosing regimen, to conduct 
an interim analysis after the 60-mg cohort or 100-mg cohort, or to stop the study. Section 7.2.2.2 
provides specifics related to dosing Cohort 8.
Dosing for the first cohort of Part B (Cohort 5) may begin simultaneously with the last cohort of 
Part A (Cohort 4). See Figure 4 for a dose escalation schematic.


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Figure 4:
Dose Escalation Schematic (Parts A and B)


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7.2.2.
Within Cohort Staggered Dosing
7.2.2.1.
Part A: Single Ascending Dose
For the first 3 dose levels in Part A (10, 20, and 40 mg), participants will be randomized in 
blocks of 4 to receive BIIB067 or placebo in a 3:1 (active treatment:placebo) ratio. The first 
2 participants in each cohort will be dosed sequentially, each followed by a 72-hour safety data 
review period, during which the Biogen Medical Director and Global Safety Physician will 
review blinded safety data with the PI. The remaining participants within the cohort will then be 
dosed at least 24 hours apart, to allow for review of safety data. Depending on the accumulated 
DLT data from the first 3 cohorts, the 8 participants in Cohort 4 (60 mg) can either be 
randomized in a single block of 8, or be divided into 2 sequential blocks of 4, with the second 
block of 4 participants starting dosing only after the 14-day safety review for the last participant 
within the first block is completed, and the accumulated DLT data have been fully reviewed. 
Dosing within each randomized block of either 8 or 4 participants will be staggered similarly as 
for Cohorts 1-3.
7.2.2.2.
Part B: Multiple Ascending Dose
Within Cohorts 5 to 7 in Part B, participants will be randomized in blocks of 4 to receive 
BIIB067 or placebo in a 3:1 (active treatment:placebo) ratio. The 3 blocks of each cohort will be 
dosed sequentially, each followed by a 72-hour safety data review period, during which the 
Biogen Medical Director and Global Safety Physician will review blinded safety data with the 
PI. 
Given that safety and tolerability of the 100-mg dose of BIIB067 were not explored in Part A 
(SAD), both a sentinel dosing strategy and a review of safety data for every participant after the 
first dose will be incorporated into Cohort 8. 
In Cohort 8, the first 2 participants (1 participant receiving placebo and 1 participant receiving 
BIIB067) will be dosed as a sentinel group, followed by a 72-hour safety data review period, 
during which the Biogen Medical Director and Global Safety Physician will review blinded 
safety data with the PI. For the remaining participants in the cohort, no more than 2 participants 
will be given the first dose of study treatment on the same day throughout the study.
Cohort 8 follows the same loading dose/maintenance dose as the other MAD cohorts. While a 
100-mg dose has not been administered in the SAD portion of the study, the safety data collected 
between Week 2 and Week 4 postdose (or even Week 1 and Week 4 postdose) did not yield any 
additional information when compared with safety data collected for the first 2 weeks postdose. 
This justifies the absence of a 4-week safety observation period between doses 1 and 2.
Additional to the 72-hour safety review period, for every participant in Cohort 8, a review of all 
available safety and tolerability data will be performed approximately 1 week after the first dose 
is administered. This review will be performed by the Biogen Medical Director and Global 
Safety Physician with the PI. The second dose cannot be given until this review is complete. 


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7.2.2.3.
Part C
As the initial safety and tolerability of 100 mg BIIB067 have previously been explored in 
Cohort 8, staggered dosing is not required for Part C of the study.
7.2.3.
Dose-Limiting Toxicity
For Parts A and B only, a DLT will be defined as an AE that, in the judgment of an Investigator 
and/or the Sponsor, is of sufficient significance to be dose limiting, is related to study treatment 
(i.e., the AE is substantially less likely to occur in participants not treated with study treatment), 
and is not a known 1) sign or symptom of ALS, or 2) effect of the LP procedure. 
For Part C, a single dose level of BIIB067 (100 mg) is to be used, and DLT evaluation will not 
be done. The dose level of 100 mg BIIB067 has been determined from interim analyses of data 
from Parts A and B of this study, in which BIIB067 at dose levels up to and including 100 mg 
was generally well tolerated. 
7.3.
Overall Study Duration and Follow-Up
The study period will consist of screening, dosing, and FU.
7.3.1.
Screening
7.3.1.1.
Part A: Single Ascending Dose
For participants who do not have documentation of an SOD1 mutation, the screening period will 
involve an additional visit (Screening Visit 1), where a blood sample will be collected for DNA 
analysis. The rationale for the extra screening visit is to ensure DNA analysis results prior to 
assessing the rest of the eligibility criteria. Participant eligibility for the study will be determined 
during Screening Visit 2, up to approximately 21 days after Screening Visit 1 and within 28 days 
prior to admission to the inpatient facility for dosing (Day 1). Participants in the 2 lowest dose 
cohorts, who choose to re-enroll into 1 of the 2 highest dose cohorts, will have to repeat 
screening assessments before receiving the second dose. This additional Screening Visit can 
occur during the washout period, within 28 days prior to their second admission to the inpatient 
facility for dosing. 
 
The Screening Visit 2 assessments may be performed over 2 days, which do not need to be 
consecutive, to minimize participant burden. All assessments must be completed before Day 1.
7.3.1.2.
Part B: Multiple Ascending Dose
For participants who do not have documentation of an SOD1 mutation, the screening period will 
involve an additional visit (Screening Visit 1), 
 
. Participant eligibility for the study will be determined during Screening Visit 2, up to 
approximately 21 days after Screening Visit 1, and within 28 days before admission to the 
inpatient facility for dosing (Day 1). 
The Screening Visit 2 assessments may be performed over 2 days to minimize participant 
burden. All assessments must be completed before Day 1.


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7.3.1.3.
Part C
Participant eligibility for Part C of the study will be determined during the Screening Visit, up to 
approximately 4 weeks prior to the first dose (Day 1). All assessments must be completed before 
Day 1. 
7.3.2.
Dosing
7.3.2.1.
Part A: Single Ascending Dose
Eligible participants will report to the study site for admission to the inpatient unit on Day 1 to 
complete baseline assessments and reaffirm eligibility. Participants will stay in the clinic until 
completion of all 24-hour postdose assessments.
7.3.2.2.
Part B: Multiple Ascending Dose
Eligible participants will report to the study site for admission to the inpatient unit on Day 1 to 
complete baseline assessments and reaffirm eligibility. Participants will stay in the clinic until 
completion of all 24-hour postdose assessments. Following the inpatient stay on Day 1, 
participants will return to the clinic on an outpatient basis to receive 4 more doses on Days 15, 
29, 57, and 85. CSF sampling on Days 15, 29, 57, and 85 will be performed predose. On dosing 
days, participants will remain under observation for approximately 6 hours after the LP 
procedure and will receive a safety FU telephone contact approximately 24 hours after the 
procedure. 
7.3.2.3.
Part C: Pivotal
Following the initial dosing on Day 1, participants will return to the clinic on an outpatient basis 
to receive up to 7 additional doses at Weeks 2 (Day 15), 4 (Day 29), 8 (Day 57), 12 (Day 85), 
16 (Day 113), 20 (Day 141), and 24 (Day 169). CSF sampling will be performed predose at all 
dosing visits. On dosing days/CSF sampling days, participants will remain under observation at 
the study site for at least 1 hour after the LP procedure and can be discharged at the discretion of 
the Investigator and in compliance with the institutional requirements once the participants have 
adequately recovered from the dosing procedure. Participants will receive a safety FU telephone 
contact approximately 24 hours after the procedure to provide information on AEs, SAEs, and 
concomitant medications or procedures.
7.3.3.
Follow-Up Procedures
7.3.3.1.
Part A: Single Ascending Dose
Following the inpatient stay, participants participating in Part A will return to the clinic for 
FU visits on Days 8, 29, and 57. On the day of CSF sampling during the FU period (Days 29 and 
57), participants will remain under observation for approximately 1 hour after the LP procedure 
and will receive a safety FU telephone contact approximately 24 hours after the procedure.
7.3.3.2.
Part B: Multiple Ascending Dose
Participants will return to the study site for FU visits after each dose on Day 8 (after first dose), 
Day 22 (after second dose), Day 36 (after third dose), Day 64 (after fourth dose), Days 92 


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and 106 (after fifth dose), and on the final study visit on Day 169. On the days of CSF sampling 
(Day 106 and Day 169), participants will remain under observation for approximately 1 hour 
after the procedure and will receive a safety FU telephone contact approximately 24 hours after 
the procedure. Participants will also receive FU telephone contacts on Day 50 (after third dose) 
and Day 78 (after fourth dose) to provide information on AEs, SAEs, and concomitant 
medications or procedures. Participants may, at the discretion of the Investigator, have the option 
of home visits for non-dosing visits that do not require CSF collection or strength and 
electrophysiological measures, which are visits on Days 8, 36, and 64.
7.3.3.3.
Part C: Pivotal 
Participants participating in Part C (Pivotal) will return to the site for an EOS Visit 4 weeks after 
their last dose (at Week 28), as described in the Schedule of Activities (Table 3) they will have 
the option to participate in the LTE study (233AS102), if eligible. This will be done without 
unblinding the treatment group.
For participants with delays between their Week 28 Visit and enrollment in the LTE study, a 
Safety FU (Alternative EOS) Visit will be conducted (either in person or by telephone contact) to 
collect AEs, SAEs, and concomitant medications or procedures. This Safety FU (Alternative 
EOS) Visit can be performed at Week 32 or prior to (within 2 days) enrollment in the LTE, 
whichever comes first.
Participants who do not roll over into the LTE study will have an additional safety FU visit 
8 weeks after their last dose (at Week 32) to collect information on AEs, SAEs, and concomitant 
medications or procedures (in person or by telephone contact). 
7.4.
Study Stopping Rules
7.4.1.
Dose Suspension (Parts A and B only)
If 1 participant experiences either an SAE or a clinically significant AE (as defined by the 
Investigator or the Sponsor), the Biogen Medical Director and Global Safety Physician will 
discuss the event with the Investigator and review the SAE form (if applicable). If the AE is 
assessed as unrelated to the study treatment by both the Investigator and the Sponsor (e.g., it is a 
known sign or symptom of ALS, or it is an effect of the LP procedure), dose suspension is not 
necessary. 
If the SAE or clinically significant AE (as determined by the Investigator or the Sponsor) is 
assessed as related to the study treatment by the Investigator or the Sponsor, all dosing will be 
suspended until the event has been fully evaluated by the Biogen Medical Director, Global 
Safety Physician, and, if required, any ad hoc members. Depending on the nature, severity, 
suspected on- or off-target toxicity, outcome, and frequency of the event, a decision (documented 
with supporting rationale) will be made to proceed with one of the following: 

Request additional safety data 

Continue dosing remaining participants within the cohort

Enroll additional participants to the current cohort 


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
Proceed with the planned dose escalation in the next cohort

Enroll additional participants to previous (lower-dose) cohort

Stop the study
The review will also include available preliminary PK data from the preceding cohort(s).
Dosing of the cohort cannot resume until Biogen completes the safety evaluation, and the 
Investigator has received written approval from Biogen to resume dosing. 
Dose suspension rules are not applicable for Part C of the study.
7.4.2.
Dose Termination 
7.4.2.1.
Parts A and B
After evaluation of safety, tolerability, and PK data by the Biogen Medical Director, Global 
Safety Physician, and, if required, any ad hoc members, further dosing at the current level and 
dose escalation will be terminated if any of the following is observed:

Two similar SAEs (unless clearly unrelated to BIIB067 upon medical review) are 
reported for 2 participants on active study treatment within the same cohort.

Three or more similar AEs (unless clearly unrelated to BIIB067 upon medical review) 
that are either not tolerable (as reported by the participants) or deemed a medically 
unacceptable risk by the Biogen Medical Director, Global Safety Physician, and, if 
required, any ad hoc members.

Sponsor requests that dosing be terminated. 
The study will be terminated if no dose is deemed to be safe. Biogen may terminate this study at 
any time, after informing the Investigator. The Investigator will be notified by Biogen if the 
study is placed on hold, completed, or closed.
7.4.2.2.
Part C
An IDMC will be formed to review ongoing safety and tolerability data. Members of the IDMC 
will not be allowed to participate as Investigators in this study. The IDMC will review safety 
data on an ongoing basis to ensure safe and proper treatment of participants. Regular IDMC 
meetings will occur approximately every 3 months after the first meeting. An IDMC charter will 
provide full guidance on the function and practices to be followed by the IDMC.
Biogen may terminate this study at any time, after informing the Investigator. The Investigator 
will be notified by Biogen if the study is placed on hold, completed, or closed.
7.5.
End of Study
The EOS is last participant, last visit for Part C (either in person or by telephone contact). In the 
event of a decision by the Sponsor to terminate the study earlier on the grounds that conducting a 
placebo-controlled study is no longer deemed ethical based on the assessment of risk-benefit of 
Study 233AS101, all participants will be invited for the EOS Visit, during which all Week 28 
assessments will be conducted. The EOS Visit should occur 4 weeks after the last dose of study 


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treatment. After completing the EOS Visit, participants will be considered study completers and 
they will have an option to participate in the LTE study, if eligible. For participants with delays 
between their Week 28 Visit and enrollment in the LTE study, a Safety FU (Alternative EOS) 
Visit will be conducted (either in person or by telephone contact) to collect AEs, SAEs, and 
concomitant medications or procedures. This Safety FU (Alternative EOS) Visit can be 
performed at Week 32 or prior to (within 2 days) enrollment in the LTE, whichever comes first. 
For participants not entering the LTE study or in the event the study is stopped early, there will 
be an additional safety FU visit 8 weeks after the last dose of study treatment.
8.
SELECTION OF PARTICIPANTS
8.1.
Parts A (SAD) and B (MAD)
8.1.1.
Inclusion Criteria
To be eligible to participate in this study, candidates must meet the following eligibility criteria 
at Screening, or at the timepoint specified in the individual eligibility criterion listed:
1. Ability to understand the purpose and risks of the study and provide signed and dated 
informed consent and authorization to use PHI in accordance with national and local 
participant privacy regulations. In the case that a participant is legally incapable of 
providing informed consent, the participant’s legally authorized representative will be 
able to provide the informed consent.
2. Aged  18 years at the time of informed consent. 
3. Weakness attributable to ALS and documented SOD1 mutation at Screening Visit 2. 
4. An FVC ≥ 50% of predicted value as adjusted for sex, age, and height (from the sitting 
position). Participants with stable FVC < 50% but ≥ 45%, whose FVC has not declined 
by more than 5% in the last 6 months may be considered for inclusion, at the discretion of 
the Investigator. 
5. If taking riluzole, participant must be on a stable dose for ≥ 30 days prior to Day 1 and 
expected to remain at that dose until the final study visit.
6. Medically able to undergo the study procedures, and to adhere to the visit schedule at the 
time of study entry, as determined by the Investigator.
7. Screening values of coagulation parameters including platelet count, INR, PT, and APTT 
should be within normal ranges. Coagulation tests may be repeated once if, in the opinion 
of the Investigator, values of the initial tests are only slightly out of range. Participants 
with nonclinically significant and stable out-of-range values may be eligible to enroll in 
the study at the discretion of the Investigator and after a consultation with the Sponsor. 
(For normal ranges, please refer to the study reference guide). 
8. Participants of childbearing potential must agree to practice effective contraception 
during the study and be willing and able to continue contraception for 5 months after 


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their last dose of study treatment. For further details of contraceptive requirements for 
this study, please refer to Section 15.5.
8.1.2.
Exclusion Criteria
Candidates will be excluded from study entry if any of the following exclusion criteria exist at 
Screening, or at the timepoint specified in the individual criterion listed:
1. History of or positive test result for HIV.
2. History of, or positive test result at Screening, for HCV Ab. 
3. Current hepatitis B infection (defined as positive for HBsAg and/or anti-HBc). 
Participants with immunity to hepatitis B from previous natural infection (defined as 
negative HBsAg, positive IgM anti-HBc, and positive anti-HBc) or vaccination (defined 
as positive anti-HBs) are eligible to participate in the study.
4. Treatment with another investigational drug (including investigational drugs for ALS 
through compassionate use programs), biological agent, or device within 1 month or 
5 half-lives of study agent, whichever is longer. Specifically, no prior treatment with 
small interfering RNA, stem cell therapy, or gene therapy is allowed.
5. Current enrollment in any other interventional study.
6. Current or anticipated need, in the opinion of the Investigator, of a DPS during the study 
period.
7. Current or recent (within 1 month) use, or anticipated need, in the opinion of the 
Investigator, of copper (II) (diacetyl-bis(N4-methylthiosemicarbazone)) or 
pyrimethamine.
8. Current or recent use (within 30 hours prior to screening), or anticipated need of 
edaravone (Radicava®).
9. Presence of any implanted vascular devices.
10. History of drug abuse or alcoholism within ≤ 6 months of study enrollment that would 
limit participation in the study, as determined by the Investigator.
11. Tracheostomy.
12. Presence of an untreated or inadequately treated active infection requiring systemic 
antiviral or antimicrobial therapy at any time during the screening period.
13. Ongoing medical condition (e.g., wasting or cachexia, severe anemia) that according to 
the Investigator would interfere with the conduct or assessments of the study. 
14. Female participants who are pregnant or currently breastfeeding.
15. Significant cognitive impairment, clinical dementia, or unstable psychiatric illness, 
including psychosis, suicidal ideation, suicide attempt, or untreated major depression 
≤ 90 days, as determined by the Investigator.
16. History of allergies to a broad range of anesthetics.


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17. Presence of risk for increased or uncontrolled bleeding and/or risk of bleeding that is not 
managed optimally and could place a participant at an increased risk for intraoperative or 
postoperative bleeding. These could include, but are not limited to, anatomical factors at 
or near the LP site (e.g., vascular abnormalities, neoplasms, or other abnormalities) and 
underlying disorders of the coagulation cascade, platelet function, or platelet count 
(e.g., hemophilia, Von Willebrand’s disease, liver disease). 
18. Anticipated need, in the opinion of the Investigator, for administration of any antiplatelet 
or anticoagulant medication (e.g., clopidogrel) for 7 days before or 48 hours after an LP. 
19. Presence of an implanted shunt for the drainage of CSF or an implanted CNS catheter.
20. Clinically significant abnormalities in hematology or clinical chemistry parameters, as 
determined by the Investigator, which would render the participant unsuitable for 
enrollment. For a list of normal, acceptable, and exclusionary ranges, please refer to the 
study reference guide.
21. Clinically significant, as determined by the Investigator, 12-lead ECG abnormalities, 
including corrected QT interval using Fridericia’s correction method of > 450 ms for 
males and > 470 ms for females.
22. Inability to comply with study requirements.
23. Other unspecified reasons that, in the opinion of the Investigator or Sponsor, make the 
participant unsuitable for enrollment.
8.2.
Part C (Pivotal)
8.2.1.
Inclusion Criteria
To be eligible to participate in Part C (Pivotal) of this study, candidates must meet the following 
eligibility criteria at Screening, or at the timepoint specified in the individual eligibility criterion 
listed:
1. Ability to understand the purpose and risks of the study and provide signed and dated 
informed consent and authorization to use PHI in accordance with national and local 
participant privacy regulations. In the case that a participant is legally incapable of 
providing informed consent, the participant’s legally authorized representative will be 
able to provide the informed consent.
2. Aged  18 years at the time of informed consent. 
3. Weakness attributable to ALS and a confirmed SOD1 mutation. 
a.
SOD1 mutation must be confirmed by the central reader based on the sample 
obtained during the Screening Visit; participants with an SOD1 mutation interpreted 
by the central reader to be pathogenic or likely pathogenic will be eligible.
b. Additionally: 

Prognostic enrichment criteria for rapid disease progression (participants may be 
eligible based on 1 of the following 2 criteria) [Hamidou 2017; Proudfoot 2016]:


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a.
One of the following SOD1 mutations and a prerandomization ALSFRS-R 
slope decline of ≥ 0.2 per month (calculated as [48-baseline score]/time 
since symptom onset):
p.Ala5Val, p.Ala5Thr, p.Leu39Val, p.Gly42Ser, p.His44Arg, p.Leu85Val, 
p.Gly94Ala, p.Leu107Val, and p.Val149Gly  
OR
b. SOD1 mutation other than those listed in item ‘a.’ with prerandomization 
ALSFRS-R slope decline of ≥ 0.9 per month (calculated as [48-baseline 
score]/time since symptom onset)

Criteria for all other eligible participants: SOD1 mutation other than those listed in 
item ‘a.’ (no ALSFRS-R slope decline requirement).
4. For participants who meet prognostic enrichment criteria for rapid disease progression, 
SVC ≥ 65% of predicted value as adjusted for sex, age, and height (from the sitting 
position). For all other eligible participants, SVC ≥ 50% of predicted value as adjusted 
for sex, age, and height (from the sitting position).
Note: For SVC testing, at least 3 acceptable tests with the 2 highest acceptable (largest 
and next largest) efforts within 150 mL of vital capacity should be achieved.
5. If taking riluzole, participant must be on a stable dose for ≥ 30 days prior to Day 1 and 
expected to remain at that dose until the final study visit.
6. If taking edaravone, participant must have initiated edaravone ≥ 60 days (2 treatment 
cycles) prior to Day 1 and expected to remain at that dose until the final study visit, 
unless the Investigator determines that edaravone should be discontinued for medical 
reasons, in which case it may not be restarted during the study. Edaravone may not be 
administered on dosing days of this study. 
7.  Medically able to undergo the study procedures and to adhere to the visit schedule at the 
time of study entry, as determined by the Investigator.
8. All women of childbearing potential must agree to practice effective contraception during 
the study and be willing and able to continue contraception for 5 months after their last 
dose of study treatment. For further details of contraceptive requirements for this study, 
please refer to Section 15.5.
8.2.2.
Exclusion Criteria
Candidates will be excluded from study entry if any of the following exclusion criteria exist at 
Screening, or at the timepoint specified in the individual criterion listed:
1. History of or positive test result for HIV.
2. Current hepatitis C infection (defined as positive HCV Ab and detectable HCV RNA). 
Participants with positive HCV Ab and undetectable HCV RNA are eligible to participate 
in the study (United States Centers for Disease Control and Prevention).


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3. Current hepatitis B infection (defined as positive for HBsAg and/or anti-HBc). 
Participants with immunity to hepatitis B from previous natural infection (defined as 
negative HBsAg, positive anti-HBc, and positive anti-HBs) or vaccination (defined as 
negative HBsAg, negative anti-HBc, and positive anti-HBs) are eligible to participate in 
the study.
4. Treatment with another investigational drug (including investigational drugs for ALS 
through compassionate use programs), biological agent, or device within 1 month or 
5 half-lives of study agent, whichever is longer. Specifically, no prior treatment with 
small interfering RNA, stem cell therapy, or gene therapy is allowed.
5. Current enrollment in any other interventional study.
6. Current or anticipated need, in the opinion of the Investigator, of a DPS during the study 
period.
7. Current or recent (within 1 month) use, or anticipated need, in the opinion of the 
Investigator, of copper (II) (diacetyl-bis(N4-methylthiosemicarbazone)) or 
pyrimethamine.
8. History of drug abuse or alcoholism within ≤ 6 months of study enrollment that would 
limit participation in the study, as determined by the Investigator.
9. Presence of an untreated or inadequately treated active infection requiring systemic 
antiviral or antimicrobial therapy at any time during the screening period.
10. Ongoing medical condition (e.g., wasting or cachexia, severe anemia) that according to 
the Investigator would interfere with the conduct or assessments of the study. 
11. Female participants who are pregnant or currently breastfeeding.
12. Significant cognitive impairment, clinical dementia, or unstable psychiatric illness, 
including psychosis, suicidal ideation, suicide attempt, or untreated major depression 
≤ 90 days, as determined by the Investigator.
13. History of allergies to a broad range of anesthetics.
14. Presence of risk for increased or uncontrolled bleeding and/or risk of bleeding that is not 
managed optimally could place a participant at an increased risk for intraoperative or 
postoperative bleeding. These could include, but are not limited to, anatomical factors at 
or near the LP site (e.g., vascular abnormalities, neoplasms, or other abnormalities) and 
underlying disorders of the coagulation cascade, platelet function, or platelet count 
(e.g., hemophilia, Von Willebrand’s disease, liver disease). 
15. Anticipated need, in the opinion of the Investigator, for administration of any antiplatelet 
or anticoagulant medication that cannot be safely held before and/or after an LP 
procedure according to local or institutional guidelines and/or Investigator determination. 
16. Presence of an implanted shunt for the drainage of CSF or an implanted CNS catheter.
17. Clinically significant abnormalities in hematology or clinical chemistry parameters, as 
determined by the Investigator, which would render the participant unsuitable for 


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enrollment. For a list of normal, acceptable, and exclusionary ranges, please refer to the 
study reference guide.
18. Clinically significant, as determined by the Investigator, 12-lead ECG abnormalities, 
including corrected QT interval using Fridericia’s correction method of > 450 ms for 
males and > 470 ms for females.
19. Inability to comply with study requirements.
20. Other unspecified reasons that, in the opinion of the Investigator or Sponsor, make the 
participant unsuitable for enrollment.


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9.
ENROLLMENT, REGISTRATION, AND RANDOMIZATION
9.1.
Screening and Enrollment
Participants (or their legally authorized representative [e.g., spouse], where applicable) must 
provide informed consent before any screening tests are performed (see Section 17.3). When a 
participant signs the ICF, that participant is considered to be enrolled in the study. Participating 
study sites are required to document all screened candidates initially considered for inclusion in 
this study. If a participant is excluded from the study, the reasons for exclusion will be 
documented in the participant’s source documents and on the screening log.
For Part C (Pivotal), participants who fail screening can be rescreened up to one time at the 
discretion of the Investigator. 
All screening assessments would need to be repeated during rescreening except for the 
following: 

FSH level in female participants with postmenopausal state confirmed by level obtained 
in previous screening for Part C of this study

Confirmation of SOD1 mutation by the central reader if available from previous 
screening for Part C (Pivotal) of this study
9.2.
Randomization and Registration of Participants
Parts A and B
Participants will be registered and randomized on Day 1, after all predose assessments have been 
completed, and after the Investigator has verified that the participants are eligible per criteria in 
Sections 8.1 and 8.2. No participant may begin treatment prior to assignment of a unique 
identification number (registration) and randomization. Any participant identification numbers 
that are assigned will not be reused, even if the participant does not receive treatment.
Participants who withdraw from the study prior to completing the final FU visit may be replaced 
at the discretion of the Sponsor. Up to 8 replacement participants may be enrolled in Part B of 
the study (2 per cohort). These additional participants will be assigned to receive the same study 
treatment as the withdrawn participants they will replace.
Part C
For Part C, participants will be registered at Screening when a centralized IRT system will assign 
a participant identification number to each participant. Once a participant has been allocated an 
identification number, he or she is considered registered for the study. The participant’s 
identification number will be used on all of that participant’s CRFs and on all laboratory and 
other requisition forms. Any participant identification numbers that are assigned will not be 
reused even if the participant does not receive treatment. 
If a participant is excluded from the study, the reasons for exclusion will be documented in the 
participant’s source documents and on the screening log. Participants in Part C will be 
randomized on Day 1 after all predose assessments have been completed and after the 
Investigator has verified that the participants are eligible per criteria in Sections 8.2.1 and 8.2.2 


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and that all criteria to determine which stratum the participant should be randomized to have 
been correctly entered in the IRT system. These criteria include whether the participant meets the 
prognostic enrichment criteria for rapid disease progression, SVC, riluzole use, and edaravone 
use. No participant may begin treatment prior to randomization. 
Eligible participants will be randomized in a 2:1 ratio to receive BIIB067 100 mg or placebo, 
respectively. Randomization will be stratified by 3 factors: 1) whether a participant meets the 
prognostic enrichment criteria for rapid disease progression; 2) whether a participant uses 
edaravone at baseline; and 3) whether a participant uses riluzole at baseline. Use of edaravone 
and riluzole will not be a separate stratum but will be classified as edaravone use.
Refer to the study reference guide for details on registration and randomization.
9.3.
Blinding Procedures
This is a randomized, double-blind, placebo-controlled study.
Investigators, study staff (except for a designated pharmacist/technician), and study participants 
will be blinded to the randomized study treatment assignments. The designated unblinded Study 
Pharmacy Staff will dispense the study treatment according to the DHA and randomization 
schedule and will not have responsibilities for any other study assessments. 
To maintain the study blind, it is imperative that participant treatment assignments are not shared 
with the participants, their families, or any member of the study team, either at the study site or 
at Biogen, except the unblinded designated Study Pharmacy Staff and designated Biogen 
personnel.
For Parts A and B only, the Biogen Medical Director, Global Safety Physician, Biostatistician, 
Clinical Pharmacologist, and, if required, any ad hoc members, may be unblinded in order to 
review all safety and available PK data, to assess safety and tolerability, and to make informed 
decisions regarding dose escalation (Section 7.2.1).
At each study site, a qualified and trained study site staff member will consistently perform the 
ALSFRS-R for a participant and will remain blinded both to the participants’ treatment 
assignments and to the results of other assessments.
At the end of the study (i.e., once the clinical study report is finalized), if unblinding will not 
jeopardize the results of ongoing related studies, Biogen will provide the randomization codes to 
Investigators, who then can inform their participants about the treatment received. 
For information pertaining to unblinding for medical emergencies, see Section 15.4.3.1.


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10.
DISCONTINUATION OF STUDY TREATMENT OR 
WITHDRAWAL OF PARTICIPANTS FROM THE STUDY
10.1.
Withdrawal from the Study (Part A) or Discontinuation of Study 
Treatment (Parts B and C)
A participant must be withdrawn from Part A of the study (SAD), or permanently discontinue 
study treatment in Part B (MAD) and Part C (Pivotal) of the study, for any of the following 
reasons:

The participant becomes pregnant. Study treatment must be discontinued 
immediately. Report the pregnancy according to the instructions in Section 15.4.1.

The participant withdraws consent to continue study treatment. 

The participant experiences a medical emergency that necessitates permanent 
discontinuation of study treatment.

The participant experiences a medical emergency that necessitates unblinding of the 
participant’s treatment assignment.

The participant is unwilling or unable to comply with the protocol.

At the discretion of the Investigator or Sponsor.
The reason for discontinuation of study treatment must be recorded in the participant’s CRF.
Participants who discontinue treatment in Part B may remain in the study and continue 
protocol-required tests and assessments.
Participants who discontinue study treatment in Part C will be encouraged to remain in the study 
and complete all appropriate protocol-specified tests and assessments. It is recommended that 
participants who terminate early (i.e., discontinue both study treatment and study assessments) 
perform the assessments of the EOS Visit (Week 28 Visit) within 4 weeks after the last dose of 
study treatment. Home assessments will be allowed at the discretion of the Investigator for 
participants who cannot come to the site in person for their Early Termination Visit. 


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11.
STUDY TREATMENT USE
11.1.
Regimen
Each participant will receive a 15-mL intrathecal bolus (over 1-3 minutes) of study treatment 
(BIIB067 or placebo). Prior to injection, approximately 10 mL of CSF will be collected for 
analyses. Depending on institutional guidelines, anesthesia or sedation may be used for the LP 
procedure. Detailed instructions are provided in the DHA. 
11.1.1.
BIIB067
In Part A (SAD), a single dose of BIIB067 will be administered by intrathecal bolus over 
1-3 minutes at the following planned dose levels: 
Cohort 1: BIIB067 10 mg (FIH dose)
Cohort 2: BIIB067 20 mg
Cohort 3: BIIB067 40 mg
Cohort 4: BIIB067 60 mg
In Part B (MAD), 5 doses of BIIB067 will be administered by intrathecal bolus over 1-3 minutes 
as follows: a loading regimen of 3 doses on Days 1, 15, and 29, followed by maintenance dosing 
on Days 57 and 85 for each cohort. The following dose levels are planned:
Cohort 5: BIIB067 20 mg
Cohort 6: BIIB067 40 mg
Cohort 7: BIIB067 60 mg
Cohort 8: BIIB067 100 mg
In Part C (Pivotal), 8 doses of BIIB067 100 mg will be administered by intrathecal bolus over 
1-3 minutes as follows: a loading regimen of 3 doses on Days 1, 15, and 29, followed by 
5 maintenance doses every 28 days (or 4 weeks).
11.1.2.
Placebo
Matching placebo will be administered by intrathecal bolus over 1-3 minutes, following the same 
dosing regimen as BIIB067, for each cohort.
11.2.
Modification of Dose and/or Treatment Schedule
The dosage should not be modified, other than as stated in Section 7.2.1. However, for Parts A 
and B only, if necessary (e.g., dose is not tolerated), after review of all available data by the 
Biogen Medical Director, a Global Safety Physician, the PI, and, if required, any ad hoc 
members, an alternative dose or dosing regimen may replace the planned dose or dosing regimen 
for the subsequent cohort.
No dosage modification will be done in Part C.


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11.3.
Concomitant Therapy and Procedures
11.3.1.
Concomitant Therapy
A concomitant therapy is any drug or substance administered between Day 1 and the final study 
visit (Day 57 for participants participating in Part A [SAD] only; Day 169 for participants 
participating in both Parts A [SAD] and B [MAD] or in Part B [MAD]; and Day 197 or Day 225 
for participants participating in Part C [Pivotal] only).
11.3.1.1.
Allowed Concomitant Therapy
Participants taking concomitant riluzole at study entry must be on a stable dose for 30 days prior 
to the first dose of study treatment (Day 1) and must continue with the same dose regimen 
throughout the study, unless the Investigator determines that riluzole should be discontinued for 
medical reasons, in which case it may not be restarted.
For Part C, participants taking concomitant edaravone at study entry must have initiated 
edaravone≥ 60 days (2 treatment cycles) prior to the first dose of study treatment (Day 1) and 
must continue with the same dose regimen throughout the study, unless the Investigator 
determines that edaravone should be discontinued for medical reasons, in which case it may not 
be restarted during the study. Edaravone may not be administered on dosing days of this study.
Concomitant medication for symptom management during the study is at the discretion of the 
Investigator. Participants with questions about allowed concomitant therapy should seek medical 
guidance from the Investigator.
Daily intake of all concomitant vitamins and supplements should be stabilized at least 14 days 
prior to Day 1. Doses of vitamins, minerals, and supplements greater than the recommended 
daily dose should be discouraged during the study.
Supplements that are subject to dose limits from at least 14 days prior to Day 1 and that should 
remain stable throughout the study are as follows: creatine 5 g per day and vitamin E 1000 IU 
per day. These daily limits include the total doses obtained through the combination use of daily 
multivitamins and supplements.
11.3.1.2.
Disallowed Concomitant Therapy
Any antiplatelet or anticoagulant medication that cannot be safely held before and/or after an LP 
procedure according to local or institutional guidelines and/or Investigator determination is 
prohibited for the duration of the study.
Use of DPS, copper (II) (diacetyl-bis(N4-methylthiosemicarbazone)), or pyrimethamine is 
prohibited for the duration of the study. 
Off-label use of any disease-modifying treatment for ALS is prohibited for the duration of the 
study.
Participants should be instructed to contact their Investigator before taking any new medications, 
including nonprescription drugs and herbal preparations. 


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11.3.2.
Concomitant Procedures
A concomitant procedure is any therapeutic intervention (e.g., surgery/biopsy, physical therapy) 
or diagnostic assessment (e.g., blood gas measurement, bacterial cultures) performed between 
the time the participant is enrolled in the study and the final FU visit.


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12.
STUDY TREATMENT MANAGEMENT
Study site staff should follow the DHA for specific instructions on the handling, preparation, 
administration, and disposal of the study treatment. The DHA aligns with all other references, 
including the protocol.
Study treatment must be dispensed only by a Pharmacist or appropriately qualified staff. Study 
treatment is to be dispensed only to participants enrolled in this study. Once study treatment is 
prepared for a participant, it can be administered only to that participant. Study treatments are for 
one-time use only; do not use any study treatment remaining in the vial for another participant.
12.1.
BIIB067
For Parts A and B, Biogen will supply BIIB067 as a liquid in vials containing approximately 
5.5 mL per vial, to ensure 5.0 mL deliverable volume. The drug product is a sterile, parenteral 
solution formulation that contains BIIB067 drug product 20 mg/mL, sodium dihydrogen 
phosphate dihydrate 0.050 mg/mL, sodium phosphate dibasic anhydrous 0.097 mg/mL, sodium 
chloride 7.597 mg/mL, potassium chloride 0.224 mg/mL, calcium chloride dihydrate 
0.206 mg/mL, and magnesium chloride hexahydrate in water for injection 0.163 mg/mL. If 
necessary, pH is adjusted to a target pH of 7.2 with hydrogen chloride or sodium hydroxide 
during compounding.
For Part C, Biogen will supply BIIB067 as a liquid in vials containing approximately 16.4 mL 
per vial, to ensure 15.0 mL deliverable volume after withdrawal from vial and dose preparation. 
The drug product is a sterile, parenteral solution formulation that contains BIIB067 drug product 
6.7 mg/mL, sodium dihydrogen phosphate dihydrate 0.03 mg/mL, sodium phosphate dibasic 
anhydrous 0.11 mg/mL, sodium chloride 8.77 mg/mL, potassium chloride 0.22 mg/mL, calcium 
chloride dihydrate 0.21 mg/mL, and magnesium chloride hexahydrate in water for injection 
0.16 mg/mL, pH 7.2. 
The contents of the BIIB067 label will be in accordance with all applicable regulatory 
requirements. At a minimum, the label will include a study reference code, study treatment 
identifier, quantity of dosage units, lot number, and other pertinent information in accordance 
with local law. The expiry or use-by date will be stored in the IRT system, and printable 
assignment reports will be available to site personnel. BIIB067 should not be used after the 
expiration date. 
12.1.1.
BIIB067 Preparation
The individual preparing BIIB067 should carefully review the instructions provided in the DHA.
If the packaging is damaged, or if there is anything unusual about the appearance or attributes of 
the vials or study treatment, then the study treatment should not be used. The vial in question 
should be saved at the study site, and the problem should be reported to Biogen immediately.
12.1.2.
BIIB067 Storage
Study treatment must be stored in a secure location. 


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BIIB067 is to be protected from light and stored at 2C to 8C (36F to 46F), in a monitored, 
locked refrigerator, with limited access. For the most up-to-date storage requirements, follow the 
instructions provided in the DHA.
12.1.3.
BIIB067 Handling and Disposal
The Investigator must return all used and unused vials of BIIB067 as instructed by Biogen, 
unless approved for onsite destruction.
If any BIIB067 supplies are to be destroyed at the study site, the institution or appropriate site 
personnel must obtain prior approval from Biogen, by providing, in writing, the destruction 
policy or details of the method of destruction. After such destruction, Biogen must be notified, in 
writing, of the details of the study treatment destroyed (e.g., lot or kit numbers, quantities), the 
date of destruction, and proof of destruction.
12.1.4.
BIIB067 Accountability
Accountability for study treatment is the responsibility of the Investigator. The study site must 
maintain accurate records demonstrating dates and amount of study treatment received, to whom 
dispensed (participant-by-participant accounting), and accounts of any study treatment 
accidentally or deliberately destroyed or lost. 
Unless otherwise notified, all vials both used and unused, must be saved for study treatment 
accountability. At the end of the study, reconciliation must be made between the amount of 
BIIB067 supplied, dispensed, and subsequently destroyed, lost, or returned to Biogen. A written 
explanation must be provided for any discrepancies.
12.2.
Placebo Product
Biogen manufactures the matching placebo (artificial CSF), supplied as a liquid in vials 
containing approximately 20 mL per vial for use in Parts A and B and approximately 21 mL per 
vial for use in Part C. The drug supply label will include conditions for storage, lot number, and 
other pertinent information. 
Placebo is to be stored at 2C to 8C (36F to 46F), in a monitored, locked cabinet with limited 
access.












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14.
SAFETY ASSESSMENTS
Refer to Section 4 for the timing of all safety assessments.
14.1.
Clinical Safety Assessments
The following clinical assessments will be performed to evaluate the safety profile of BIIB067:

Medical history

Physical examinations

Limited neurological examinations (to be assessed by a trained specialist) of: 

cranial nerves, coordination/cerebellar function, reflexes, motor, and MMSE (a 
30-point questionnaire that is used to measure cognitive impairment) [in Part B]

MMSE, motor, reflexes, and coordination/cerebellar function (in Part C) 

Vital sign measurements: temperature, pulse rate, systolic and diastolic blood 
pressure, and respiratory rate will be performed after the participant has rested in a 
sitting position for at least 5 minutes

Weight measurements

12-Lead ECGs in triplicate (paper, as applicable)

C-SSRS

Concomitant therapy and procedure recording

AE and SAE recording
14.2.
Laboratory Safety Assessments
The following laboratory assessments will be performed to evaluate the safety profile of 
BIIB067:

Hematology: complete blood count with differential and platelet count.

Coagulation: INR, PT, and APTT

Blood chemistry: total protein, albumin, creatinine, blood urea nitrogen, uric acid, 
bilirubin (total and direct), alkaline phosphatase, alanine aminotransferase, aspartate 
aminotransferase, gamma-glutamyl transferase, glucose, calcium, phosphorus, 
bicarbonate, chloride, sodium, and potassium

Urinalysis: dipstick for blood, protein, and glucose (microscopic examination, if 
abnormal) 

Urine and/or serum pregnancy tests

CSF analysis: red blood cell count, white blood cell count, protein, and glucose  


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14.3.
Product-Specific Safety Assessments
Anti-BIIB067 Ab assessments will be performed according to the schedule provided in 
Section 4.


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15.
SAFETY DEFINITIONS, RECORDING, REPORTING, AND 
RESPONSIBILITIES
Throughout the course of the study, every effort must be made to remain alert to possible AEs. If 
an AE occurs, the first concern should be for the safety of the participant. If necessary, 
appropriate medical intervention should be provided.
At the signing of the ICF, each participant or his/her legally authorized representative and/or 
main caregiver must be given the names and telephone numbers of study site staff for reporting 
AEs and medical emergencies.
15.1.
Definitions
15.1.1.
Adverse Event
An AE is any untoward medical occurrence in a patient or clinical investigation participant 
administered a pharmaceutical product and that does not necessarily have a causal relationship 
with this treatment. An AE can therefore be any unfavorable and unintended sign (including an 
abnormal laboratory finding), symptom, or disease temporally associated with the use of a 
medicinal (investigational) product, whether or not related to the medicinal (investigational) 
product.
Determination of whether an abnormal laboratory value meets the definition of an AE will be 
made by the Investigator. Although abnormal laboratory values are typically not considered AEs, 
the following considerations may result in an abnormal laboratory value being considered an AE:

A laboratory test result that meets the criteria for an SAE

A laboratory test result that requires the participant to receive specific corrective 
therapy

A laboratory abnormality that the Investigator considers to be clinically significant
15.1.2.
Serious Adverse Event
An SAE is any untoward medical occurrence that at any dose:

Results in death

In the view of the Investigator, places the participant at immediate risk of death (a 
life-threatening event); however, this does not include an event that, had it occurred 
in a more severe form, might have caused death

Requires inpatient hospitalization or prolongation of existing hospitalization

Results in persistent or significant disability/incapacity

Results in a congenital anomaly/birth defect

Is a medically important event
An SAE may also be any other medically important event that, in the opinion of the Investigator, 
may jeopardize the participant or may require intervention to prevent one of the other outcomes 


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listed in the definition above. (Examples of such medical events include allergic bronchospasm 
requiring intensive treatment in an emergency room or convulsions occurring at home that do not 
require an inpatient hospitalization.)
15.1.3.
Prescheduled or Elective Procedures or Routinely Scheduled Treatments
A prescheduled or elective procedure or a routinely scheduled treatment, including 
hospitalization that is part of the study design (e.g., admission to the clinic for the purposes of 
dosing or post-LP observation) will not be considered an SAE, even if the participant is 
hospitalized. The study site must document all of the following:

The prescheduled or elective procedure or routinely scheduled treatment was 
scheduled (or was on a waiting list to be scheduled) prior to obtaining the 
participant’s consent to participate in the study.

The condition requiring the prescheduled or elective procedure or routinely scheduled 
treatment was present before and did not worsen or progress in the opinion of the 
Investigator between the participant’s consent to participate in the study and the time 
of the procedure or treatment.

The prescheduled or elective procedure or routinely scheduled treatment is the sole 
reason for the intervention or hospital admission.

If a participant is hospitalized due to local requirements for administration of the 
study treatment, the hospitalization should not be considered an SAE unless one 
of the requirements in Section 15.1.2 is met.
15.2.
Safety Classifications
15.2.1.
Investigator Assessment of Events
All events must be assessed to determine the following:

If the event meets the criteria for an SAE as defined in Section 15.1.2.

The relationship of the event to study treatment as defined in Section 15.2.2.

The severity of the event as defined in Section 15.2.3.


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15.2.2.
Relationship of Events to Study Treatment
The following definitions should be considered when evaluating the relationship of AEs and 
SAEs to the study treatment.
Relationship of Event to Study Treatment
Not related
An AE will be considered “not related” to the use of the investigational drug if there is 
not a reasonable possibility that the event has been caused by the product under 
investigation. Factors pointing toward this assessment include, but are not limited to, 
the lack of reasonable temporal relationship between administration of the drug and the 
event, the presence of a biologically implausible relationship between the product and 
the AE, or the presence of a more likely alternative explanation for the AE.
Related
An AE will be considered “related” to the use of the investigational drug if there is a 
reasonable possibility that the event may have been caused by the product under 
investigation. Factors that point toward this assessment include, but are not limited to, a 
positive rechallenge, a reasonable temporal sequence between administration of the 
drug and the event, a known response pattern of the suspected drug, improvement 
following discontinuation or dose reduction, a biologically plausible relationship 
between the drug and the AE, or a lack of an alternative explanation for the AE.
Relationship of Event to Lumbar Puncture
Not related
An AE will be considered “not related” to the LP procedure if there is not a reasonable 
possibility that the event has been caused by the LP procedure. Factors pointing toward 
this assessment include, but are not limited to, the lack of reasonable temporal 
relationship between the LP procedure and the event, the presence of a biologically 
implausible relationship between the LP procedure and the AE, or the presence of a 
more likely alternative explanation for the AE.
Related
An AE will be considered “related” to the LP procedure if there is a reasonable 
possibility that the event may have been caused by the LP procedure. Factors that point 
toward this assessment include, but are not limited to, a reasonable temporal sequence 
between the LP procedure and the event, a known response pattern of the LP procedure 
(e.g., bleeding from the puncture site), a biologically plausible relationship between the 
LP procedure and the AE, or a lack of an alternative explanation for the AE.
15.2.3.
Severity of Events
The severity of AEs and SAEs will be graded using the National Cancer Institute CTCAE, 
version 4. Any AE not listed in the CTCAE will be graded as follows:


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Severity of Event
Grade
Definition
1
Mild AE
2
Moderate AE
3
Severe or medically significant AE
4
Life-threatening AE
5
Death related to AE
15.2.4.
Expectedness of Events
Expectedness of all AEs will be determined by Biogen according to the Investigator’s Brochure. 
15.3.
Monitoring and Recording Events
15.3.1.
Adverse Events
Any AE experienced by the participant between the time of first dose of study treatment and the 
last FU visit is to be recorded on the CRF, regardless of the severity of the event or its 
relationship to study treatment. At each study visit, each post-LP telephone contact, the EOS 
Visit (Part C Week 28), or the Safety FU (Alternative EOS) Visit (Week 32) for participants who 
do not roll over or have delays in rollover into the LTE Study 233AS102), the Investigator will 
assess the participant for AEs and will record any new AEs or updates to previously reported 
AEs on the CRF.
15.3.2.
Serious Adverse Events
Any SAE experienced by the participant between the time of the signing of the first (main) ICF 
and the last FU visit is to be recorded on an SAE form, regardless of the severity of the event or 
its relationship to study treatment. SAEs must be reported to Biogen within 24 hours as described 
in Section 15.3.3. FU information regarding an SAE also must be reported within 24 hours. 
Participants will be followed for all SAEs until the final study visit. Thereafter, the event should 
be reported to Biogen only if the Investigator considers the SAE to be related to study treatment.
Any SAE that is ongoing when the participant completes or discontinues the study will be 
followed by the Investigator until the event has resolved, stabilized, or returned to baseline 
status.
15.3.3.
Immediate Reporting of Serious Adverse Events
In order to adhere to all applicable laws and regulations for reporting an SAE, the study site must 
formally notify Biogen within 24 hours of the study site staff becoming aware of the SAE. It is 
the Investigator’s responsibility to ensure that the SAE reporting information and procedures are 
used and followed appropriately.


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Reporting Information for SAEs
A report must be submitted to Biogen regardless of the following:

Whether or not the participant has undergone study-related procedures

Whether or not the participant has received study treatment

The severity of the event

The relationship of the event to study treatment
To report initial or FU information on an SAE, fax or email a completed SAE form; refer to 
the Study Reference Guide for complete contact information.
15.3.3.1.
Deaths
Death is an outcome of an event. The event that resulted in death should be recorded on the 
appropriate CRF. All causes of death must be reported as SAEs within 24 hours of the site 
becoming aware of the event. The Investigator should make every effort to obtain and send death 
certificates and autopsy reports to Biogen. The term death should be reported as an SAE only if 
the cause of death is not known and cannot be determined.
15.3.4.
Suspected Unexpected Serious Adverse Reactions
SUSARs are SAEs that are unexpected and judged by the Investigator or Biogen to be related to 
the study treatment administered.
Appropriate personnel at Biogen will unblind SUSARs for the purpose of regulatory reporting. 
Biogen will submit SUSARs (in blinded or unblinded fashion) to regulatory agencies according 
to local law. Biogen will submit SUSARs to Investigators in a blinded fashion.
15.4.
Procedures for Handling Special Situations
15.4.1.
Pregnancy
Participants should not become pregnant during the study and for 5 months after their last 
dose of study treatment. If a female participant becomes pregnant, study treatment must be 
discontinued immediately.
The Investigator must report a pregnancy occurring in a female participant by faxing or emailing 
the appropriate form to Biogen within 24 hours of the study site staff becoming aware of the 
pregnancy; refer to the Study Reference Guide for complete contact information. The 
Investigator or study site staff must report the outcome of the pregnancy to Biogen. A pregnancy 
is not considered an AE and should not be recorded on the AE CRF.
Congenital abnormalities and birth defects in the offspring of male or female participants should 
be reported as an SAE if conception occurred during the study treatment period.


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15.4.2.
Overdose
An overdose is any dose of study treatment administered to a participant or taken by a participant 
that exceeds the dose assigned to the participant according to the protocol. Overdoses are not 
considered AEs and should not be recorded as an AE on the CRF; however, all overdoses must 
be recorded on an Overdose form and faxed or emailed to Biogen within 24 hours of the site 
becoming aware of the overdose. An overdose must be reported to Biogen even if the overdose 
does not result in an AE. If an overdose results in an AE, the AE must be recorded. If an 
overdose results in an SAE, both the SAE and Overdose forms must be completed and faxed or 
emailed to Biogen; refer to the Study Reference Guide for complete contact information. All 
study treatment-related dosing information must be recorded on the dosing CRF.
15.4.3.
Medical Emergency
In a medical emergency requiring immediate attention, study site staff will apply appropriate 
medical intervention, according to current standards of care. The Investigator (or designee) 
should contact the study’s Medical Director. Refer to the Study Reference Guide’s Official Study 
Contact List for complete contact information.
15.4.3.1.
Unblinding for Medical Emergency
In a medical emergency when knowledge of the participant’s treatment assignment may 
influence the participant’s clinical care, the Investigator and, if applicable, designated personnel 
at Biogen may access the participant’s treatment assignment by IRT. The Investigator must 
document the reasons for unblinding in the participant’s source documents. The Investigator is 
strongly advised not to divulge the participant’s treatment assignment to any individual not 
directly involved in managing the medical emergency, nor to personnel involved with the 
analysis and conduct of the study. The Investigator can contact Biogen or designee to discuss 
such situations.
15.5.
Contraception Requirements
All women of childbearing potential must ensure that effective contraception is used during the 
study and for 5 months after their last dose of study treatment. In addition, female participants 
should not donate eggs for the duration of the study and for at least 5 months after their last dose 
of study treatment.
For the purposes of this study, women who do not meet one of the following criteria are 
considered to be physiologically capable of becoming pregnant and are, therefore, defined as 
women of childbearing potential:

Postmenopausal

12 continuous months of natural (spontaneous) amenorrhea without an alternative 
medical cause and a serum FSH level > 40 mIU/mL 

6 weeks after surgical bilateral oophorectomy with or without hysterectomy

Posthysterectomy

Female surgical sterilization (e.g., bilateral tubal ligation) 


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For the purposes of the study, effective contraception is defined as use of at least 1 of the 
following: 
For females:

Established use of oral, injected, implanted, intravaginal, or transdermal hormonal 
methods of contraception.

Placement of an intrauterine device or intrauterine hormone-releasing system.

Barrier methods of contraception with use of a spermicide: condom or occlusive cap 
(diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream suppository. 
The use of barrier contraceptives should always be supplemented with the use of a 
spermicide.

Sex with a male who has undergone surgical sterilization (with the appropriate 
postvasectomy documentation of the absence of sperm in the ejaculate). 
True abstinence, when this is consistent with the preferred and usual lifestyle of the participant, 
can be considered an acceptable method of contraception based on the evaluation of the 
Investigator who should also take into consideration the duration of the clinical trial. Periodic 
abstinence (e.g., calendar, ovulation, symptothermal, postovulation methods) and withdrawal are 
not considered acceptable methods of contraception.
Pregnancy reporting is described in Section 15.4.1.
15.6.
Safety Responsibilities
15.6.1.
The Investigator
The Investigator’s responsibilities include the following:

Monitor and record all AEs, including SAEs, regardless of the severity or relationship 
to study treatment.

Determine the seriousness, relationship, and severity of each event.

Determine the onset and resolution dates of each event.

Monitor and record all pregnancies, and follow up on the outcome of the pregnancy 
in female participants.

Complete an SAE form for each SAE and fax or email it to Biogen within 24 hours of 
the study site staff becoming aware of the event.

Pursue SAE FU information actively and persistently. FU information must be 
reported to Biogen within 24 hours of the study site staff becoming aware of new 
information.

Ensure all AE and SAE reports are supported by documentation in the participants’ 
medical records.

Pursue AE FU information, if possible, until the event has resolved or become stable.


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
Report SAEs to local ethics committees, as required by local law.
15.6.2.
Biogen 
Biogen’s responsibilities include the following:

Before study site activation and participant enrollment, the Clinical Monitor is 
responsible for reviewing with study site staff the definitions of AE and SAE, as well 
as the instructions for monitoring, recording, and reporting AEs and SAEs.

Biogen is to notify all appropriate regulatory authorities, central ethics committees, 
and Investigators of SAEs, as required by local law, within required time frames.


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16.
STATISTICAL METHODS AND DETERMINATION OF 
SAMPLE SIZE
The objectives of the study and the endpoints to be analyzed are listed in Section 6.
16.1.
Part A (SAD) and Part B (MAD)
The ITT population is defined as all randomized participants who receive at least 1 or a part of 
1 dose of study treatment.
16.1.1.
Clinical Function
16.1.1.1.
Analysis Population
The clinical function set is defined as the subset of the ITT population who have at least 
1 postdose measurement.
All participants receiving placebo will be combined to form placebo control groups for Part A 
(SAD) and for Part B (MAD). A separate statistical analysis will be performed for Part A (SAD) 
and for Part B (MAD).
16.1.1.2.
Methods of Analysis
The change and percent change from baseline in 
 HHD, ALSFRS-R, SVC, 
 will be summarized by visit and dose level using 
descriptive statistics and, where warranted, presented graphically. A 2-sample Student’s t-test 
will be used to compare these data between each dose of BIIB067 and placebo at a 2-sided alpha 
level of 0.10. 
16.1.2.
Pharmacokinetics
16.1.2.1.
Analysis Population
The PK population is defined as the subset of the ITT population of participants with at least 
1 postdose PK measurement.
16.1.2.2.
Methods of Analysis
Plasma and CSF PK parameters and BIIB067 concentrations in plasma and CSF for the PK 
population will be summarized using descriptive statistics and, where warranted, presented 
graphically.
16.1.3.
Pharmacodynamics
16.1.3.1.
Analysis Population
The PD population is defined as the ITT population of participants with at least 1 PD 
measurement after baseline.


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16.1.3.2.
Methods of Analysis
Changes and percent changes from baseline for total SOD1 protein levels will be summarized 
and presented by visit and by dose level. A 2-sample Student's t-test will be used to compare 
each dose of BIIB067 and placebo at a 2-sided alpha level of 0.10.
16.1.4.
Biomarker and Pharmacogenomic Analyses
16.1.4.1.
Analysis Population
The biomarker population is defined as the ITT population of participants with at least 
1 postbaseline biomarker measurement.
16.1.4.2.
Methods of Analysis
CSF and blood samples may be assayed for biomarkers that may include, but will not be limited 
to, 
 pNfH, and NfL.
Exploratory potential biomarker candidates related to BIIB067 biological activity will be 
summarized using descriptive statistics and will be presented by dose level.
Summary statistics (raw and logarithmic scale) for the above potential biomarkers will be 
calculated and presented by dose level and by visit, and their mean and median levels will be 
plotted over time, as appropriate.
See Section 4 for information on when samples will be collected.
Sampling for this analysis will be approved at the discretion of each site’s ethics committee. If a 
site’s ethics committee does not approve the sampling for the analysis, this section will not be 
applicable to that site.
16.1.5.
Safety
16.1.5.1.
Analysis Population
The safety population is defined as the ITT population of participants.
16.1.5.2.
Methods of Analysis
16.1.5.2.1. Adverse Events
AEs will be coded using MedDRA.
The incidence of all AEs and SAEs will be summarized by system organ class and preferred term 
for each dose level. AEs will also be summarized by severity and relationship to study treatment. 
Narratives of deaths, SAEs, and AEs that led to study withdrawal, at a minimum, will also be 
provided.
16.1.5.2.2. Clinical Laboratory Results
Clinical laboratory evaluations include hematology, coagulation, blood chemistry, and urinalysis. 
Laboratory data will be summarized using shift tables. The number and percentage of 
participants with shifts from baseline to high or low status for hematology, coagulation, and 


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blood chemistry, and shifts from baseline to high or positive status for urinalysis will be 
presented by dose level. In addition, summaries of the shift from baseline to the maximum 
postbaseline value and the shift from baseline to the minimum postbaseline value will presented 
by cohort. 
16.1.5.2.3. Vital Signs
Changes from baseline will be summarized for all vital signs by dose levels. A separate summary 
will be presented for incidence of clinically significant changes from baseline.
16.1.5.2.4. Columbia Suicide Severity Rating Scale
C-SSRS data will be summarized by dose level using descriptive statistics (number of 
participants, mean, SD, median, minimum, and maximum) for continuous variables, and using 
frequency and percentage for discrete variables.
16.1.5.2.5. Physical Examinations
The changes from baseline will be summarized by dose level.
16.1.5.2.6. Limited Neurological Examinations
The changes from baseline in the limited neurological examination (MMSE, cranial nerves, 
coordination/cerebellar function, motor and reflexes) will be summarized by dose level.
16.1.5.2.7. Electrocardiogram
The changes from baseline will be summarized using shift tables. The number and percentage of 
participants with shifts to the categorical values (abnormal not AE, or abnormal and AE) will be 
summarized by dose level. 
16.1.6.
Antigenicity/Immunogenicity Data
16.1.6.1.
Analysis Population
The analysis population for immunogenicity is defined as all participants who receive at least 
1 dose of study treatment and have at least 1 postdose immunogenicity sample collected.
16.1.6.2.
Methods of Analysis
Results will be summarized by dose level.
16.1.7.
Interim Analyses
In Part A (SAD) of the study, CRM will be used as supporting evidence for continuous 
assessment of MTD for dose escalation decisions. In Part B (MAD) of the study, in addition to 
the safety review (blinded), a designated team of staff will review the available unblinded but 
de-identified PD and/or biomarker data (e.g., levels of total SOD1 protein and pNfH) from all 
previous cohorts at the completion of the last Day 106 visit of each cohort to determine whether 
to proceed with the subsequent planned dose cohorts. An interim analysis of key safety, 
secondary, and exploratory endpoints may be conducted based on data up to the 60-mg and/or 


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100-mg dose cohort to allow for the planning of the pivotal efficacy and safety study. The 
participants, investigative staff, and sponsor’s staff responsible for site monitoring and data 
management will remain blinded to treatment assignment during the ongoing data review, as 
well as during interim analyses, to minimize the potential for bias in the data cleaning process. 
Details of the interim analysis will be provided in a separate statistical analysis plan.
16.1.8.
Sample Size Considerations
The maximum sample size of 36 participants for Part A of the study (SAD) is based on clinical 
rather than statistical considerations. Participants will be randomized to receive BIIB067 or 
placebo in a 3:1 ratio in each cohort. Each cohort will have a minimum of 4 participants (3 active 
and 1 placebo), and a maximum of 12 participants (9 active and 3 placebo). The final number for 
each cohort will be dependent on the DLT profile. If no DLT occurs in any dose level, then a 
total of 20 participants (15 active and 5 placebo) will be randomized. This design will allow for 
adequate evaluation of the safety of BIIB067, should DLT be encountered, as well as minimize 
participant exposure at subtherapeutic single doses.
For Part B (MAD), up to 48 participants will be enrolled in up to 4 cohorts, with up to 
9 participants randomized to receive BIIB067 and 3 participants randomized to receive placebo 
for each cohort. This design will provide approximately 80% power to detect a difference in total 
SOD1 protein reduction between 25% from the BIIB067 group and 12% from the placebo group 
at a 10% significance level. The sample size calculation assumes the same 10.5% SD in the 
2 treatment groups.
16.2.
Part C
The ITT population is defined as all participants who are randomized and receive at least 1 dose 
of study treatment.
16.2.1.
Clinical Function
16.2.1.1.
Analysis Population
The primary analyses of clinical function will be evaluated in the mITT population (see 
Section 8.2.1 for definition) comprising the subset of the population who meet prognostic 
enrichment criteria for rapid disease progression who are randomized and receive at least 1 dose 
of study treatment. The primary analysis population will comprise participants who meet 
prognostic enrichment criteria for rapid disease progression to enable detection of a statistically 
significant and clinically meaningful treatment effect on clinical function over the 6-month 
treatment duration. The treatment effect of clinical function endpoints in the non-mITT 
population will be analyzed, where relevant, with nominal p-values presented. The clinical 
function data in the overall ITT population will be summarized and analyzed where relevant.
16.2.1.2.
Methods of Analysis
16.2.1.2.1. Analysis of the Primary Efficacy Endpoint
The primary efficacy endpoint is the change from baseline to Week 28 in the ALSFRS-R total 
score, which will be analyzed as follows, depending on 2 scenarios:


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1. If the number of deaths across both treatment arms is ≥ 3 (i.e., ≥ 5% deaths out of a total 
of 60 patients in the mITT population), the JRT methodology to account for mortality 
[Berry 2013] will be used for the primary inference. When implementing the JRT 
methodology, MI will be used to handle withdrawals. The estimates will be obtained 
from an ANCOVA for change from baseline in ALSFRS-R at Week 28 with missing data 
imputed using MI. The corresponding nominal p-value from the ANCOVA will be 
presented as a sensitivity analysis. 
2. If the number of deaths is < 3 (i.e., < 5% deaths out of a total of 60 patients in the mITT 
population), ANCOVA with MI will be used as the primary analysis method for both 
inference and estimates. The p-value from the JRT will be presented as a sensitivity 
analysis.
The primary estimand is described as follows:
The primary analysis for the primary endpoint is the composite estimand [ICH 2017]. The 
estimand of the primary analysis is defined as follows:

Population: all participants in the mITT population.

Variable: change from baseline to Day 197 in the ALSFRS-R total score.

Handling of intercurrent events: Relevant intercurrent events are handled using a 
composite strategy in which participants who have these intercurrent events are 
ranked against each other and against participants without any intercurrent event 
using the joint rank methodology based on MI datasets. The relevant intercurrent 
events are deaths and withdrawals. These participants will be handled using the 
composite strategy and ranked as described in this section. For withdrawals, this will 
be based on the imputed value for Day 197 from the MI datasets. 

Summary statistics: difference between treatment groups in least square means of 
Day 197 change from baseline with corresponding standard errors and 95% 
confidence intervals taken from the ANCOVA for change from baseline to Day 197, 
based on the MI datasets. The ANCOVA model will include treatment group as a 
fixed effect and covariates for ALSFRS-R total score, baseline disease duration since 
symptom onset, and use of riluzole or edaravone. 
For the JRT analysis, the ranked scores will be analyzed for each of the 
100 MI-complete datasets using an ANCOVA model with treatment included as a 
fixed effect and adjusted for the following covariates: baseline disease duration since 
symptom onset, baseline ALSFRS-R total score, and use of riluzole or edaravone. 
The p-value will be based on combining the estimates for the treatment differences 
using PROC MIANALYZE. The difference between treatment groups in median 
changes from baseline to each visit will be presented with 95% confidence intervals 
based on the MI datasets, as well as the p-value from the JRT for Day 197. The joint 
rank analysis will only be performed for the mITT population. 
The joint rank procedure allows for a statistical test of the treatment effect on the ALSFRS-R 
total score while accounting for truncation of data due to deaths. In this analysis, a participant’s 
joint rank score will be calculated by comparing each participant to every other participant in the 


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study, resulting in a score of +1 if the outcome was better than the participant being compared, -1 
if worse, and 0 if the same. The participant’s score will then be calculated by summing their 
comparison to all the other participants in the study. 
For the purpose of this calculation, participants will be grouped into the following 2 categories:

Group 1: Participants who complete the study and have data available at the Day 197 
assessment AND participants who withdraw from the study due to reasons other than 
death

Group 2: Participants who die
MI will be used to impute all missing data before determining the rank score, including 
intermittent data and data after withdrawal from the study except after death.
In each of the 100 imputed datasets, participants will be ranked as follows:

Participants in Group 2 will be given lower ranks than participants in Group 1, with 
the lowest ranks being given to the participants who die in the shortest time after first 
dose. Progressively higher ranks will be given to participants who die at longer times 
after first dose.

Participants in Group 1 will rank higher than participants in Group 2. Progressively 
higher ranks will be given to participants with a higher change from baseline at 
Day 197, i.e., a smaller decline at Day 197.
Further details will be described in the statistical analysis plan. 
The primary inference will be based on the mITT population. The treatment comparison will be 
based on a 2-sided α level of 0.05. 
If the second scenario occurs, i.e., in both the active and placebo treatment groups combined the 
number of participants who died is < 3 (e.g., < 5% deaths out of a total of 60 participants in the 
mITT population), the primary efficacy analysis will be the change from baseline in ALSFRS-R 
total score, analyzed using an ANCOVA based on data imputed using MI. The ANCOVA model 
will include treatment group as a fixed effect and covariates for each of the corresponding 
baseline value for ALSFRS-R total score, baseline disease duration since symptom onset and use 
of riluzole or edaravone. The primary inference will be based on the treatment comparison at 
Week 28. A 2-sided α level of 0.05 will be used. Treatment differences at other visits will also be 
presented with nominal p-values.
Sensitivity, supplementary and subgroup analyses of the primary efficacy endpoint will be 
specified in the statistical analysis plan.
For the non-mITT population, the analysis will be the change from baseline in ALSFRS-R total 
score, analyzed using an ANCOVA based on data imputed using MI. The ANCOVA model will 
include treatment group as a fixed effect and covariates for each of the corresponding baseline 
value for ALSFRS-R total score, baseline disease duration since symptom onset, and use of 
riluzole or edaravone. Least square means with standard errors will be presented for each 
treatment group. The difference between treatment groups in least square means for change from 
baseline at each visit, with corresponding standard errors and 95% confidence intervals, will be 
presented with nominal p-values.


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16.2.1.2.2. Analysis of the Secondary Efficacy Endpoints
Formal testing of secondary efficacy endpoints will be in the mITT population alone. For the 
non-mITT and ITT populations, there will be no formal testing of efficacy endpoints. Testing of 
PD endpoints is discussed in Section 16.2.3. The analyses of secondary endpoints for the mITT 
population will be based on a sequential testing procedure in the order of the rank of secondary 
endpoints as listed below if the primary endpoint is statistically significant at a 2-sided α level 
of 0.05:

Change from baseline (i.e., ratio) to Week 28 (Day 197) in CSF total SOD1 protein

Change from baseline (i.e., ratio) to Week 28 (Day 197) in NfL in plasma

Change from baseline to Week 28 (Day 197) in SVC

Change from baseline to Week 28 (Day 197) in HHD megascore to assess muscle 
strength, as measured by the HHD device

Time to death or permanent ventilation, which is defined as the time to the earliest 
occurrence of one of the following events:

Death 

Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or 
noninvasive] per day for ≥ 21 consecutive days)

Time to death
The treatment effect will be assessed at each step at a 2-sided α level of 0.05. The primary 
inference at each step will be based on the mITT population.
This procedure will control the Type I error for the secondary endpoints. If statistical 
significance is not achieved for a secondary endpoint, all secondary endpoints of a lower rank 
will not be considered statistically significant. 
There will be no adjustment for multiple testing for the sensitivity or supplementary analyses for 
the primary and secondary endpoints, the exploratory endpoints or subgroup analyses.
The first and second endpoints in the ranking are PD endpoints, for which the analysis is 
described in Section 16.2.3.
The third secondary endpoint will be change from baseline to Day 197 in percent predicted SVC. 
If the number of deaths across both treatment arms is ≥ 3 (i.e., ≥ 5% deaths out of a total of 
60 patients in the mITT population), the primary inference will be based on the JRT 
methodology with MI to impute missing data; ANCOVA with MI for change from baseline will 
be used to obtain the estimates, and nominal p-values will be presented. If the number of deaths 
is < 3 (i.e., < 5% deaths out of a total of 60 patients in the mITT population), ANCOVA with MI 
will be used as the primary analysis of this endpoint. The ANCOVA model will include 
treatment group as a fixed effect and covariates for baseline percent predicted SVC, baseline 
disease duration since symptom onset, and use of riluzole or edaravone. Treatment differences at 
other visits will also be derived from the model for exploratory purpose.




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16.2.4.
Safety
16.2.4.1.
Analysis Population
The safety population will be defined as all participants who received at least 1 dose of study 
treatment (i.e., the overall ITT population).
16.2.4.2.
Methods of Analysis
All AEs, laboratory data, ECG, neurological and physical examinations, and vital signs will be 
evaluated for safety.
16.2.4.2.1. Adverse Events
Only TEAEs will be presented in the summary tables. Treatment-emergent is defined as having 
an onset date that is on or after start of study treatment, or that is worsened after the start of study 
treatment.
Incidence of TEAEs will be summarized by treatment groups, overall, by severity, by 
relationship to LP, and by relationship to study treatment. SAEs, discontinuations and 
withdrawals due to AEs, AEs leading to hospitalization, and deaths will also be summarized or 
listed, depending on number of events. The summary tables will include incidence estimates for 
overall system organ class as well as for preferred terms within each system organ class. AEs 
will be coded using MedDRA. A subset of AE outputs will also be presented by disease 
progression subgroup (“participants who meet prognostic enrichment criteria for rapid disease 
progression”, “other eligible participants”).
16.2.4.2.2. Clinical Laboratory Results
Laboratory data will be summarized using shift tables. Shifts from baseline to high/low status for 
hematology and blood chemistry parameters, and shifts from baseline to high/positive status for 
urinalysis will be presented. In addition, the shift from baseline to the maximum postbaseline 
value and the shift from baseline to the minimum postbaseline status will be presented for each 
laboratory test by treatment group. Summary statistics for actual values and change from 
baseline will also be presented for quantitative laboratory data. 
16.2.4.2.3. Vital Signs
The analysis of vital signs will focus on clinically relevant abnormalities. 
16.2.4.2.4. Electrocardiogram
The number and percentage of participants with shifts to categorical values (abnormal not AE, or 
abnormal AE) will be summarized by treatment group. 
16.2.4.2.5. Columbia Suicide Severity Rating Scale
The C-SSRS data will be summarized by treatment group.


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16.2.5.
Participant-Reported Outcomes on Quality of Life
16.2.5.1.
Analysis Population
The analysis of the participant-reported outcome endpoints will be performed primarily for the 
mITT population but also for the non-mITT population. 
16.2.5.2.
Methods of Analysis
The quality of life measures will be analyzed using an ANCOVA with MI with fixed effect for 
treatment and covariates for corresponding baseline value, baseline disease duration since 
symptom onset and use of riluzole or edaravone. The treatment difference at Day 197 will be 
derived from the model. Treatment differences at other visits will also be derived from the model 
for exploratory purpose. Nominal p-values will be presented.
16.2.6.
Interim Analyses
There will be no interim analysis performed.
16.2.7.
Sample Size Considerations
For Part C, approximately 99 participants will be randomized, with approximately 66 participants 
administered BIIB067 100 mg and approximately 33 participants administered placebo in a 2:1 
ratio.
This sample size for Part C is selected primarily based on the JRT combining the Week 28 
change from baseline in ALSFRS-R and mortality in the mITT population (N = 60). The 
observed results from an interim analysis of Study 233AS101 in participants who met the 
prognostic criteria for rapid disease progression as well as the observed ALSFRS-R slope decline 
in participants who received placebo in a similar ALS population with SOD1 mutation [Benatar 
2018] are the basis of assumed treatment effect and the variability. Participants from both 
datasets were matched with the prognostic criteria for rapid disease progression specified in this 
protocol for Part C (i.e., one of the protocol-defined SOD1 mutations and a prerandomization 
ALSFRS-R slope decline of ≥ 0.2 per month or a prerandomization ALSFRS-R slope decline of 
≥ 0.9 with SOD1 mutation NOT on the protocol-defined list). This resulted in a total of 12 
placebo control participants who met the prognostic criteria for rapid disease progression (8 from 
the historical placebo data [Benatar 2018] and 4 from Study 233AS101) and 4 matched 
participants treated with BIIB067 100 mg from interim data of a very small cohort in Study 
233AS101. The observed mean slope of decline was -3.83 for the matched placebo participants 
and -0.74 for the matched BIIB067 100 mg participants, with a pooled SD of 3.166. In the 12 
matched participants on placebo, there was 1 death and 2 participants with permanent assisted 
ventilation less than 6 months but none in the BIIB067 100 mg matched participants. Based on 
this and overall survival data in patients who met the prognostic criteria for rapid disease 
progression from the literature on patientss with an A4V SOD1 mutation, the survival at Week 
28 was assumed to be 82% in the placebo control and 90% in the BIIB067 100 mg group. 
Under the above assumptions, with N = 60 participants in the mITT population and a two-sided 
significance level of 0.05, the JRT gives 84% power. Because events of death have been factored 
into the analysis, no sample size overage is planned for missing values. 


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For the non-mITT population, the primary focus will be on the PD endpoint, CSF total SOD1 
protein concentration, as this population is anticipated to have a slower decline in clinical 
function compared to the mITT population. A sample size of 26 participants in the treated group 
and 13 participants in the placebo group for the non-mITT population would provide 97% power 
to detect a 25% reduction in CSF total SOD1 protein from baseline in the treated group, with an 
assumed SD of 0.216 (natural log scale), compared to the placebo group. 


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17.
ETHICAL REQUIREMENTS
Biogen and the Investigator must comply with all instructions, regulations, and agreements in 
this protocol and applicable ICH and GCP guidelines and conduct the study according to local 
regulations.
The Investigator may delegate responsibilities for study-related tasks where appropriate to 
individuals sufficiently qualified by education, training, and experience, in accordance with 
applicable ICH and GCP guidelines. The Investigator should maintain a list of the appropriately 
qualified persons to whom significant study-related duties have been delegated.
17.1.
Declaration of Helsinki
This study will be performed in alignment with the ethical principles outlined in the Declaration 
of Helsinki.
17.2.
Ethics Committee
The Investigator must obtain ethics committee approval of the protocol, ICF, and other required 
study documents prior to starting the study. Biogen will submit documents on behalf of the 
investigational sites. 
If the Investigator makes any changes to the ICF, Biogen must approve the changes before the 
ICF is submitted to the ethics committee. A copy of the approved ICF must be provided to 
Biogen. After approval, the ICF must not be altered without the agreement of the relevant ethics 
committee and Biogen.
It is the responsibility of the Investigators to ensure that all aspects of institutional review are 
conducted in accordance with current applicable regulations.
Biogen must receive a letter documenting ethics committee approval, which specifically 
identifies the protocol, protocol number, and ICF, prior to the initiation of the study. Protocol 
amendments will be subject to the same requirements as the original protocol.
A progress report must be submitted to the ethics committee at required intervals and not less 
than annually.
At the completion or termination of the study, the investigational site must submit a close-out 
letter to the ethics committee and Biogen.
17.3.
Participant Information and Consent
Prior to performing any study-related activities under this protocol, including screening tests and 
assessments, written informed consent with the approved ICF must be obtained from the 
participant or participant’s legally authorized representative (e.g., spouse), as applicable, in 
accordance with local practice and regulations. 
The background of the proposed study, the procedures, the benefits and risks of the study, and 
that study participation is voluntary for the participant must be explained to the participant (or 
the participant’s legally authorized representative). The participant must be given sufficient time 
to consider whether to participate in the study.


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Participants will be informed, where applicable, that their race and ethnicity will be collected 
during the study (unless the collection is not permitted by applicable law or not approved by the 
governing ethics committee) and the data will be used during analysis of study results. 
A copy of the signed and dated ICF must be given to the participant or the participant’s legally 
authorized representative. The signed and dated ICF will be retained with the study records. 
Local regulations must be complied with in respect to the final disposition of the original (wet 
signature) and copies of the signed and dated ICFs.
Confirmation of informed consent must also be documented in the participant’s medical record.
17.4.
Participant Data Protection
Prior to any testing under this protocol, including screening tests and assessments, candidates 
must also provide all authorizations required by local law (e.g., PHI authorization in North 
America).
During the study, participants’ race and ethnicity will be collected (unless the collection is not 
permitted by applicable law or not approved by the governing ethics committee). These data will 
be used in the analysis of the safety and/or PK profile of the study treatment. It is unknown 
whether the effects of the study treatment are influenced by race or ethnicity. 
The participant will not be identified by name in the CRF or in any study reports, and these 
reports will be used for research purposes only. Biogen, its partners and designees, ethics 
committees, and various government health agencies may inspect the records of this study. Every 
effort will be made to keep the participant’s personal medical data confidential.
17.5.
Compensation for Injury
Biogen maintains appropriate insurance coverage for clinical studies and will follow applicable 
local compensation laws.
17.6.
Conflict of Interest
The Investigators should address any potential conflicts of interest (e.g., financial interest in 
Biogen or partnering companies) with the participant before the participant makes a decision to 
participate in the study.
17.7.
Registration of Study and Disclosure of Study Results
Biogen will register the study and post study results regardless of outcome on a publicly 
accessible website in accordance with the applicable laws and regulations.


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18.
ADMINISTRATIVE PROCEDURES
18.1.
Study Site Initiation
The Investigator must not screen any participants prior to completion of a study initiation visit, 
conducted by Biogen or designee. This initiation visit will include a detailed review of the 
protocol and study procedures.
18.2.
Quality Assurance
During and/or after completion of the study, quality assurance officers named by Biogen or the 
regulatory authorities may wish to perform onsite audits or inspections. The Investigator will be 
expected to cooperate with any audit or inspection and to provide assistance and documentation 
(including source data) as requested.
18.3.
Monitoring of the Study
The Investigator must permit study-related monitoring by providing direct access to source data 
and to the participants’ medical histories. Source data must be attributable, legible, 
contemporaneous, original, accurate, and complete. Changes to source data must be traceable, 
not obscure the original entry, and be explained if necessary (e.g., with an audit trail). The 
Investigator should maintain a record of the location(s) of essential documents.
The Clinical Monitor will visit the Investigator at regular intervals during the study and after the 
study has completed, as appropriate. During these visits, CRFs and supporting documentation 
related to the study will be reviewed and any discrepancies or omissions will be resolved. 
Remote evaluation of data (centralized monitoring) and remote verification of source 
documentation may also be conducted and reported as defined in the monitoring plan.
Monitoring visits must be conducted according to the applicable ICH and GCP guidelines to 
ensure protocol adherence, quality of data, study treatment accountability, compliance with 
regulatory requirements, and continued adequacy of the investigational site and its facilities.
18.4.
Study Funding
Biogen is the Sponsor of the study and is funding the study. All financial details are provided in 
the separate contracts between the institution, Investigator, and Biogen. 
18.5.
Publications
Details are included in the clinical trial agreement for this study.


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19.
FURTHER REQUIREMENTS AND GENERAL INFORMATION
19.1.
Public Health Emergencies
In the event of a public health emergency that results in site closure, travel restrictions, and/or the 
study being deprioritized at the site such that clinic visit(s) cannot occur, a protocol deviation 
would be incurred for any deviation from the protocol-specified visits and assessments, with 
additional notation that this protocol deviation is due to the public health emergency. If a 
protocol-specified clinical visit cannot occur due to a public health emergency, the following 
mitigating options should be pursued, in order of preference (in which the highest preference 
option that is feasible should be done): 1) transfer to another active study site that is open, 2) 
home visit, 3) telemedicine visit (e.g., by telephone or web conference), and 4) local laboratory 
visit. These mitigating options only apply in the setting of a public health emergency in which a 
protocol-specified clinic visit cannot occur and should not be pursued solely due to participant’s 
preference. 
A third-party vendor has been engaged to perform the following assessments at the study 
participant’s home:
1. Limited neurological examination, including the MMSE
2. Physical examination
3. Vital signs
4. Height and body weight collection
5. SVC
7. Pregnancy test (if applicable)
8. HHD
10. Collection/shipment of ventilation diary records
The following assessments can be performed via the phone (telemedicine) by the site staff:
1. ALSFRS-R
4. Assessing changes in signs and symptoms as well as review of concomitant medications 
and AEs
The following assessments can be performed at the study participant’s home OR via the phone 
(telemedicine) by the site staff:
1.  Health outcome measures
a.




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19.3.
Study Committees
19.3.1.
Safety Surveillance Team
A safety surveillance team, consisting, at a minimum, of the Biogen Medical Director and a 
Global Safety Physician will monitor dose escalation, as described in Section 7.2.1.
19.3.2.
Independent Data Monitoring Committee
An IDMC will be formed to review ongoing safety and tolerability data, as described in 
Section 7.4.2.2. 
19.3.3.
Endpoint Adjudication Committee
In Part C, time to death or permanent ventilation will be determined in a blinded fashion by a 
central, independent EAC. Procedures for reviewing and adjudicating events are described in the 
Charter that governs the operation of the EAC. 
19.4.
Changes to Final Study Protocol
All protocol amendments must be submitted to the ethics committee and regulatory authorities if 
required by local law. Protocol modifications that affect participant safety, the scope of the 
investigation, or the scientific quality of the study must be approved by the ethics committee 
before implementation of such modifications to the conduct of the study. If required by local 
law, such modifications must also be approved by the appropriate regulatory agency prior to 
implementation.
However, Biogen may, at any time, amend this protocol to eliminate an apparent immediate 
hazard to a participant. In this case, the appropriate regulatory authorities will be notified 
subsequent to the modification.
In the event of a protocol modification, the ICF may require similar modifications (see 
Section 17).
19.5.
Ethics Committee Notification of Study Completion or Termination
Where required, the regulatory authorities and ethics committees must be notified of completion 
or termination of this study, and sent a copy of the study synopsis in accordance with necessary 
timelines.
19.6.
Retention of Study Data
The minimum retention time for study records will meet the strictest standard applicable to that 
site, as dictated by any institutional requirements or local laws or regulations. Prior to proceeding 
with destruction of records, the Investigator must notify Biogen in writing and receive written 
authorization from Biogen to destroy study records. In addition, the Investigator must notify 
Biogen of any changes in the archival arrangements, including but not limited to, archival at an 
offsite facility or transfer of ownership if the Investigator leaves the site.


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19.7.
Study Report Signatory
Biogen will designate one of the participating Study Investigators as a signatory for the study 
report. This determination will be made by several factors, including but not limited to, the 
Investigator’s experience and reputation in the studied indication; the Investigator’s contribution 
to the study in terms of design, management, and/or participant enrollment; or by other factors 
determined to be relevant by Biogen.


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20.
REFERENCES
Amyotrophic Lateral Sclerosis Online Genetics Database (ALSoD). 2015.
Andersen PM, Nilsson P, Keränen ML, et al. Phenotypic heterogeneity in motor neuron disease 
patients with CuZn-superoxide dismutase mutations in Scandinavia. Brain. 1997;120 ( Pt 
10):1723-37.
Benatar M, Wuu J, Andersen PM, et al. Randomized, double-blind, placebo-controlled trial of 
arimoclomol in rapidly progressive. Neurology. 2018;90(7):e565-e574. Epub 2018/01/24.
Berry JD, Miller R, Moore DH, et al. The Combined Assessment of Function and Survival 
(CAFS): a new endpoint for ALS clinical trials. Amyotroph Lateral Scler Frontotemporal 
Degener. 2013;14(3):162-8. Epub 2013/01/17.
Bruijn LI, Cleveland DW. Mechanisms of selective motor neuron death in ALS: insights from 
transgenic mouse models of motor neuron disease. Neuropathol Appl Neurobiol. 
1996;22(5):373-87.
Bruijn LI, Houseweart MK, Kato S, et al. Aggregation and motor neuron toxicity of an ALS-
linked SOD1 mutant independent from wild-type SOD1. Science. 1998;281(5384):1851-4.
Cedarbaum JM, Stambler N, Malta E, et al. The ALSFRS-R: a revised ALS functional rating 
scale that incorporates assessments of respiratory function. BDNF ALS Study Group (Phase III). 
J Neurol Sci. 1999;169(1-2):13-21.
Cudkowicz ME, McKenna-Yasek D, Sapp PE, et al. Epidemiology of mutations in superoxide 
dismutase in amyotrophic lateral sclerosis. Ann Neurol. 1997;41(2):210-21.
Fischer LR, Li Y, Asress SA, et al. Absence of SOD1 leads to oxidative stress in peripheral 
nerve and causes a progressive distal motor axonopathy. Exp Neurol. 2012;233(1):163-71.
Gurney ME, Pu H, Chiu AY, et al. Motor neuron degeneration in mice that express a human 
Cu,Zn superoxide dismutase mutation. Science. 1994;264(5166):1772-5.
Hamidou B, Marin B, Lautrette G, et al. Exploring the diagnosis delay and ALS functional 
impairment at diagnosis as relevant criteria for clinical trial enrolment. Amyotroph Lateral Scler 
Frontotemporal Degener. 2017;18(7-8):519-527. Epub 2017/08/01.
International Council For Harmonisation Of Technical Requirements For Pharmaceuticals For 
Human Use. E9(R1) Statistical Principles for Clinical Trials: Addendum: Estimands and 
Sensitivity Analysis in Clinical Trials.
Miller MR, Crapo R, Hankinson J, et al. General considerations for lung function testing. Eur 
Respir J. 2005;26(1):153-61.
Miller RG, Mitchell JD, Moore DH. Riluzole for amyotrophic lateral sclerosis (ALS)/motor 
neuron disease (MND). Cochrane Database Syst Rev. 2012;3:CD001447.




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21.
SIGNED AGREEMENT OF THE STUDY PROTOCOL
I have read the foregoing protocol, “A Study to Evaluate the Efficacy, Safety, Tolerability, 
Pharmacokinetics, and Pharmacodynamics of BIIB067 Administered to Adult Subjects with 
Amyotrophic Lateral Sclerosis and Confirmed Superoxide Dismutase 1 Mutation,” and agree to 
conduct the study according to the protocol and the applicable ICH guidelines and GCP 
regulations, and to inform all who assist me in the conduct of this study of their responsibilities 
and obligations.
____________________________________________________
Investigator’s Signature
Date
____________________________________________________
Investigator’s Name (Print)
____________________________________________________
Study Site (Print)


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APPENDIX A. CONTINUOUS REASSESSMENT METHOD
A CRM is a working model that operates by continuously refining the assumptions about the 
dose toxicity relationship after each participant or group of participants are dosed and observed 
[O'Quigley 1990]. By utilizing the information from nonclinical and clinical studies, and 
continuously updating the information during the study, the CRM is able to minimize the number 
of participants exposed to lower doses, which are not expected to be effective, and obtain a more 
accurate estimate of the MTD. The MTD for this therapy is defined as the highest tested dose 
with a less than 33% DLT rate at Day 15. 
With this CRM, the DLT rate will be continuously assessed as data from groups of 4 participants 
(3 randomized to active treatment and 1 to placebo) becomes available. The first group will 
receive the lowest dose level (10 mg). For dose escalation or de-escalation decisions, no more 
than 1 dose level will be allowed at a time. The CRM algorithm requires specifying prior 
distributions on the model parameter. A vague prior distribution is normally utilized based on 
nonclinical animal toxicology data and relevant clinical data. Whenever DLT data from each 
group of participants are available, the parametric model will be updated with all the 
accumulated DLT data. The posterior probability of DLT of each dose will be calculated and 
used to find the highest dose that has at most 50% posterior probability of being intolerable (i.e., 
DLT rate > 33%).
Specifically, the probability of observing a DLT, p(x) at each dose level (d) will be estimated 
through a 2-parameter logistic model:
P(Y = 1|dose = x=log(d/10)) = p(x) = exp(β0+ β1x)/[1+ exp(β0+ β1x) ],
where Y is the binary indicator of a DLT for a given dose d, and x is the standardized dose for d, 
in reference to the 10-mg dose. At the beginning of the study, we set slightly informative prior 
distributions for the 2 logistic regression parameters, the intercept (β0) and the slope (β1) as 
follows: β0~ N(-3.89, 1.02) and β1 ~ N(1.82, 0.32)I(0, ∞). The truncated normal distribution for β1 
ensures that the probability of DLT is a monotonic increasing function of dose. After DLT data 
from 15 participants receiving active treatment are available, the prior distribution for β0 will be 
replaced by N(-3.89, 2.02). Similarly, after DLT data from the 60 mg cohort are available, the 
prior distribution for β1 will be replaced by N(1.82, 0.62)I(0,∞). Such change will ensure that the 
dose toxicity curve is more driven by the safety data collected toward the end of the study.
These initial prior distributions are selected so that the induced prior distributions on DLT rate 
will yield a median DLT rate of approximately 2% (95% credible interval 0.003, 0.127) at the 
10-mg dose, and approximately 35% (95% credible interval 0.054, 0.832) at the 60-mg dose. The 
expected DLT rates were determined based on the safety data on BIIB067 from the toxicology 
study in monkeys, where no clinical findings were observed, and from prior clinical trials, where 
up to 12 mg of other ASO treatments were shown to be well tolerated in repeated-dose studies in 
patients with ALS or spinal muscular atrophy. Toward the end of the study, the prior 
distributions β0~ N(-3.89,2.02) and β1 ~ N(1.82, 0.62)I(0,∞) will induce prior distributions with 
the same median DLT rate but much wider 95% credible intervals (0, 0.513 for 10-mg and 0.006, 
0.979 for 60-mg dose, respectively).


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The details of the CRM algorithm are as follows:
Step 1: The first group of participants will be assigned to the lowest dose level, i.e., 10 mg. Set 
d1*=log(d1/10)=0.
Step 2: For any group k, we calculate the posterior probability of DLT rate ≥ 33% for all d1*,… 
dr*, where di* =log(di/10),
πk(di*) = P(p(di*) ≥ 0.33 | yk), i=1,…, r,
where yk denotes the DLT data collected from the first (k-1) groups. 
The kth group will be assigned to the highest planned dose level whose posterior probability of 
DLT rate larger than 33% is less than 50%, with a restriction to a change of no more than one 
dose level at a time. 
Step 2 will be repeated until one of the following conditions is encountered:
1. a total of 27 active and 9 placebo participants have been enrolled, or
2. the highest planned dose has tested 6 active and 2 placebo participants and the posterior 
probability of DLT rate of the highest dose larger than 33% is less than 20%, or
3. MTD dose has tested 9 active and 3 placebo participants.
At the completion of the trial, the highest tested dose with less than 50% posterior probability of 
being intolerable will be labeled as the MTD, or highest tested safe dose, which will be based on 
all the trial data, including the last group of participants.


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1
Biogen MA Inc.
225 Binney Street
Cambridge, MA  02142
United States
Biogen Idec Research Limited
Innovation House
70 Norden Road
Maidenhead, Berkshire
SL6 4AY
United Kingdom
______________________________________________________________________
AMENDMENT SUMMARY
Biogen Protocol 233AS101
A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation
Version 8
Date: 15 June 2021
EUDRA CT Number: 2015‐004098‐33
Version 8 of the protocol has been prepared for this amendment, which supersedes Version 7.


Amendment Summary for Protocol 233AS101, Version 8
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PRIMARY REASON FOR AMENDMENT
The primary reason for this amendment to Protocol 233AS101 is to update to reflect the final 
statistical analysis plans.
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 16.2.1.2.1, Analysis of the Primary Efficacy Endpoint
Change: The statistical methodology was updated consistent with the study's Statistical Analysis 
Plan.
Now reads:
The primary efficacy endpoint is the change from baseline to Week 28 in the ALSFRS-R total 
score, which will be analyzed using the joint rank methodology to account for mortality [Berry 
2013].  This joint ranking procedure allows for a statistical test of the treatment effect on the 
ALSFRS-R total score while accounting for loss of data due to deaths. In this analysis, a 
subject’s Combined Assessment of Function and Survival (CAFS) score will be calculated by 
comparing each subject to every other subject in the study, resulting in a score of +1 if the 
outcome was better than the subject being compared, -1 if worse, and 0 if the same.  The 
subject’s score will then be calculated by summing their comparison to all the other subjects in 
the study.
For example, if 2 subjects complete the study up to Week 28, their comparison score will be 
based on the change from baseline in ALSFRS-R total score at Week 28.  A subject who dies 
will rank lower than any subject who completes the study up to Week 28.  Two subjects who 
both die will be ranked based on the time of death, with a longer time to death corresponding to a 
higher rank.  Hence, in general, these comparisons will result in subjects who die being assigned 
the worst scores and ranked according to time of death.  Subjects who survive and complete the 
study will be ranked more favorably than subjects who die.
The ranked scores will be analyzed using an analysis of covariance model with treatment 
included as a fixed effect and adjusted for the following covariates : baseline disease duration 
since symptom onset, baseline ALSFRS-R total score, and use of riluzole or edaravone.  The 
primary inference will be based on the mITT population. The treatment comparison will be 
based on a 2-sided α level of 0.05.
If there are insufficient number of deaths, the change from baseline in ALSFRS-R total score 
will be analyzed using a mixed model for repeated measures (MMRM) with fixed effect for 
treatment, time (as a categorical variable), treatment by time interaction and adjustment for 
baseline ALSFRS-R score, baseline ALSFRS-R score by time interaction, baseline disease 
duration since symptom onset, and use of riluzole or edaravone.  An unstructured covariance 
(UN) matrix will be used to model the within subject variance-covariance errors.  The primary 


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3
inference will be based on the treatment comparison at Week 28. A 2 sided α level of 0.05 will 
be used.
Sensitivity analyses of the primary efficacy endpoint will be specified in the statistical analysis 
plan. 
The primary efficacy endpoint is the change from baseline to Week 28 in the ALSFRS-R 
total score, which will be analyzed as follows, depending on 2 scenarios:
1. If the number of deaths across both treatment arms is ≥ 3 (i.e., ≥ 5% deaths out of a 
total of 60 patients in the mITT population), the JRT methodology to account for 
mortality [Berry 2013] will be used for the primary inference. When implementing 
the JRT methodology, MI will be used to handle withdrawals. The estimates will be 
obtained from an ANCOVA for change from baseline in ALSFRS-R at Week 28 
with missing data imputed using MI. The corresponding nominal p-value from the 
ANCOVA will be presented as a sensitivity analysis. 
2. If the number of deaths is < 3 (i.e., < 5% deaths out of a total of 60 patients in the 
mITT population), ANCOVA with MI will be used as the primary analysis method 
for both inference and estimates. The p-value from the JRT will be presented as a 
sensitivity analysis.
The primary estimand is described as follows:
The primary analysis for the primary endpoint is the composite estimand [ICH E9 (R1) 
Addendum 2017]. The estimand of the primary analysis is defined as follows:

Population: all participants in the mITT population.

Variable: change from baseline to Day 197 in the ALSFRS-R total score.

Handling of intercurrent events: Relevant intercurrent events are handled using 
a composite strategy in which participants who have these intercurrent events 
are ranked against each other and against participants without any intercurrent 
event using the joint rank methodology based on MI datasets. The relevant 
intercurrent events are deaths and withdrawals. These participants will be 
handled using the composite strategy and ranked as described in this section. 
For withdrawals, this will be based on the imputed value for Day 197 from the 
MI datasets. 

Summary statistics: difference between treatment groups in least square means 
of Day 197 change from baseline with corresponding standard errors and 95% 
confidence intervals taken from the ANCOVA for change from baseline to Day 
197, based on the MI datasets. The ANCOVA model will include treatment 
group as a fixed effect and covariates for ALSFRS-R total score, baseline disease 
duration since symptom onset, and use of riluzole or edaravone. 


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For the JRT analysis, the ranked scores will be analyzed for each of the 
100 MI-complete datasets using an ANCOVA model with treatment included as 
a fixed effect and adjusted for the following covariates: baseline disease duration 
since symptom onset, baseline ALSFRS-R total score, and use of riluzole or 
edaravone. The p-value will be based on combining the estimates for the 
treatment differences using PROC MIANALYZE. The difference between 
treatment groups in median changes from baseline to each visit will be presented 
with 95% confidence intervals based on the MI datasets, as well as the p-value 
from the JRT for Day 197. The joint rank analysis will only be performed for the 
mITT population. 
The joint rank procedure allows for a statistical test of the treatment effect on the 
ALSFRS-R total score while accounting for truncation of data due to deaths. In this 
analysis, a participant’s joint rank score will be calculated by comparing each participant 
to every other participant in the study, resulting in a score of +1 if the outcome was better 
than the participant being compared, -1 if worse, and 0 if the same. The participant’s score 
will then be calculated by summing their comparison to all the other participants in the 
study. 
For the purpose of this calculation, participants will be grouped into the following 2 
categories:

Group 1: Participants who complete the study and have data available at the 
Day 197 assessment AND participants who withdraw from the study due to 
reasons other than death

Group 2: Participants who die
MI will be used to impute all missing data before determining the rank score, including 
intermittent data and data after withdrawal from the study except after death.
In each of the 100 imputed datasets, participants will be ranked as follows:

Participants in Group 2 will be given lower ranks than participants in Group 1, 
with the lowest ranks being given to the participants who die in the shortest time 
after first dose. Progressively higher ranks will be given to participants who die 
at longer times after first dose.

Participants in Group 1 will rank higher than participants in Group 2. 
Progressively higher ranks will be given to participants with a higher change 
from baseline at Day 197 i.e., smaller decline at Day 197.
Further details will be described in the statistical analysis plan. 
The primary inference will be based on the mITT population. The treatment comparison 
will be based on a 2-sided α level of 0.05. 


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If the second scenario occurs, i.e., in both active and placebo treatment groups combined 
the number of participants who died is < 3 (e.g., < 5% deaths out of a total of 
60 participants in the mITT population), the primary efficacy analysis will be the change 
from baseline in ALSFRS-R total score, analyzed using an ANCOVA based on data 
imputed using MI. The ANCOVA model will include treatment group as a fixed effect and 
covariates for each of the corresponding baseline value for ALSFRS-R total score, baseline 
disease duration since symptom onset and use of riluzole or edaravone. The primary 
inference will be based on the treatment comparison at Week 28. A 2-sided α level of 0.05 
will be used. Treatment differences at other visits will also be presented with nominal 
p-values.
Sensitivity, supplementary and subgroup analyses of the primary efficacy endpoint will be 
specified in the statistical analysis plan.
For the non-mITT population, the analysis will be the change from baseline in ALSFRS-R 
total score, analyzed using an ANCOVA based on data imputed using MI. The ANCOVA 
model will include treatment group as a fixed effect and covariates for each of the 
corresponding baseline value for ALSFRS-R total score, baseline disease duration since 
symptom onset, and use of riluzole or edaravone. Least square means with standard errors 
will be presented for each treatment group. The difference between treatment groups in 
least square means for change from baseline at each visit, with corresponding standard 
errors and 95% confidence intervals, will be presented with nominal p-values.
Rationale:
The primary efficacy endpoint and analysis have been clarified to distinguish between the 
methodology used for statistical testing and the analysis for obtaining the estimates of the 
treatment difference.  The joint rank methodology is a statistical test of the treatment effect on 
the ALSFRS-R total score while accounting for truncation of data due to deaths. A rank score is 
calculated to obtain the p-value. As the range of this rank score depends on the sample size, it is 
not possible to provide a clinically meaningful interpretation using this score. Therefore, an 
ANCOVA on the change from baseline is used to obtain the estimates of the treatment 
difference.
The traditional joint rank method for the CAFS has also been replaced by the joint rank 
methodology with multiple imputation for handling missing data due to withdrawals. This 
provides a more robust method for the joint rank test.
For the alternative analysis when there are an insufficient number of deaths, ANCOVA with 
multiple imputation will be used to account for missing data as a more robust method, instead of 
MMRM.
There is clarification on what is deemed as an insufficient number of deaths to determine 
whether the joint rank test will be used for the primary efficacy analysis. This threshold is based 
on the duration of the study and the requirement of SVC ≥ 65% at screening for participants in 
the mITT population.


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Section 16.2.1.2.2, Analysis of the Secondary Efficacy Endpoints
Change: The ordering of secondary endpoints in the sequential testing procedure for the mITT 
population and the statistical methodology for secondary endpoints was amended for consistency 
with the study's Statistical Analysis Plan.
Now reads:
The analyses of secondary efficacy endpoints will be based on a sequential closed testing 
procedure in the order of the rank of secondary endpoints as listed in Section 6.2. The treatment 
effect will be assessed at each step at a 2-sided α level of 0.05. The primary inference at each step 
will be based on the mITT population.
The first secondary efficacy endpoint will be change from baseline to Week 28 in percent 
predicted SVC, which will be analyzed using a MMRM with fixed effect for treatment, time (as 
a categorical variable), treatment by time interaction and adjustment for baseline SVC, baseline 
SVC by time interaction, baseline disease duration since symptom onset, use of riluzole or 
edaravone. Overall treatment difference across visits and treatment difference at Week 28 will be 
derived from the model. Treatment differences at other visits will also be derived from the model 
for exploratory purpose.  
The second and third secondary efficacy endpoints, VAFS and overall survival, respectively, will 
be analyzed as time to event. Kaplan-Meier estimates of the cumulative probability of event 
occurrence over time will be determined.  Treatment comparison will be based on a stratified log 
rank test.  A Cox regression model will be used to obtain the hazard ration and 95% confidence 
intervals for each of these endpoints.
The muscle strength as measured by HHD will be summarized by individual muscles and 
megascore. The megascore will be analyzed using a MMRM with fixed effect for treatment, time 
(as a categorical variable), treatment by time interaction and adjustment for baseline HHD 
megascore, baseline HHD megascore by time interaction, baseline disease duration since 
symptom onset, and use of riluzole or edaravone.  Overall treatment difference across visits and 
treatment difference at Week 28 will be derived from the model. Treatment differences at other 
visits will also be derived from the model for exploratory purpose.
Formal testing of secondary efficacy endpoints will be in the mITT population alone. For 
the non-mITT and ITT populations, there will be no formal testing of efficacy endpoints. 
Testing of PD endpoints is discussed in Section 16.2.3. The analyses of secondary endpoints 
for the mITT population will be based on a sequential testing procedure in the order of the 
rank of secondary endpoints as listed below if the primary endpoint is statistically 
significant at a 2-sided α level of 0.05:

Change from baseline (i.e., ratio) to Week 28 (Day 197) in CSF total SOD1 
protein

Change from baseline (i.e., ratio) to Week 28 (Day 197) in NfL in plasma


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
Change from baseline to Week 28 (Day 197) in SVC

Change from baseline to Week 28 (Day 197) in HHD megascore to assess muscle 
strength, as measured by the HHD device

Time to death or permanent ventilation, which is defined as the time to the 
earliest occurrence of one of the following events:

Death 

Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or 
noninvasive] per day for ≥ 21 consecutive days)

Time to death
The treatment effect will be assessed at each step at a 2-sided α level of 0.05. The primary 
inference at each step will be based on the mITT population.
This procedure will control the Type I error for the secondary endpoints. If statistical 
significance is not achieved for a secondary endpoint, all secondary endpoints of a lower 
rank will not be considered statistically significant. 
There will be no adjustment for multiple testing for the sensitivity or supplementary 
analyses for the primary and secondary endpoints, the exploratory endpoints or subgroup 
analyses.
The first and second endpoints in the ranking are PD endpoints for which the analysis is 
described in Section 16.2.3.
The third secondary endpoint will be change from baseline to Day 197 in percent predicted 
SVC. If the number of deaths across both treatment arms is ≥ 3 (i.e., ≥ 5% deaths out of a 
total of 60 patients in the mITT population) the primary inference will be based on the JRT 
methodology with MI to impute missing data; ANCOVA with MI for change from baseline 
will be used to obtain the estimates, and nominal p-values will be presented.  If the number 
of deaths is < 3 (i.e., < 5% deaths out of a total of 60 patients in the mITT population), 
ANCOVA with MI will be used as the primary analysis of this endpoint. The ANCOVA 
model will include treatment group as a fixed effect and covariates for baseline percent 
predicted SVC, baseline disease duration since symptom onset, and use of riluzole or 
edaravone.  Treatment differences at other visits will also be derived from the model for 
exploratory purpose.
The secondary efficacy endpoints, time to death or permanent ventilation and time to 
death, will each be analyzed as time to event endpoints. Kaplan-Meier estimates of the 
cumulative probability of event occurrence over time will be determined. Treatment 
comparison will be based on a stratified log rank test. A Cox regression model will be used 
to obtain the hazard ratio and 95% confidence intervals for each of these endpoints. The 


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analysis for each endpoint will also be repeated for the non-mITT population with nominal 
p-values presented.
Rationale:
The hierarchy for the sequential closed testing procedure has been modified to account for the 
likelihood of statistical success for each endpoint in the 28-week duration of this study. CSF 
SOD1 and plasma NfL are also now included in the closed testing procedure and placed above 
SVC. Due to the COVID-19 pandemic, the level of missing data for SVC is likely to be higher 
due to individual site restrictions for handling the pandemic. The time-to-event endpoints are 
ranked lowest as the duration of the study and the inclusion criteria for SVC ≥ 65% at Screening 
in the mITT population reduces the chance to observe a large number of events in these 
endpoints over 28 weeks. It is expected that a greater treatment effect may be observed on SVC 
and muscle strength measured by HHD than on the time-to-event endpoints.
Change from baseline in SVC will be analyzed similarly to change from baseline in ALSFRS-R 
to account for mortality, depending on the number of deaths. The analysis specified provides a 
more robust method for estimating the treatment effect on this endpoint.
ANCOVA with multiple imputation is also specified as the analysis of HHD megascore instead 
of MMRM to provide a more robust method for handling missing data.
Section 6.2.1.2 Secondary Efficacy Endpoints
Change: The time to event endpoints were renamed so that VAFS was relabeled as time to death 
or permanent ventilation; and overall survival was renamed to time to death.
Now reads: 
The secondary efficacy endpoints are as follows:

Ventilation assistance free survival (VAFS), which is defined as the time to the 
earliest occurrence of 1 of the following events:
Death. 

Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or 
noninvasive] per day for ≥ 21 consecutive days).

•
Overall survival.

Time to death or permanent ventilation (≥ 22 hours of mechanical ventilation 
[invasive or noninvasive] per day for ≥ 21 consecutive days)

Time to death




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presented with nominal p-values. CSF, NFL, p NFH 
 will be 
analyzed similarly. 
Rationale: ANCOVA with multiple imputation is also specified as the analysis of PD/biomarker 
endpoints instead of MMRM to provide a more robust method for handling missing data.
This change also affects Section 6.2.3.1, Analysis Population.
Section 16.2.4.2.1, Adverse Events
Change: Included additional key AE summaries and listings to be consistent with the study's 
Statistical Analysis Plan. 
Now reads: 
Incidence of TEAEs will be summarized by treatment groups, overall, by severity, by 
relationship to LP, and by relationship to study treatment. SAEs, discontinuations and 
withdrawals due to AEs, AEs leading to hospitalization, and deaths will also be 
summarized or listed, depending on number of events. The summary tables will include 
incidence estimates for overall system organ class as well as for preferred terms within each 
system organ class. AEs will be coded using the MedDRA. A subset of AE outputs will also be 
presented by disease progression subgroup ("participants who met prognostic enrichment 
criteria for rapid disease progression", "other eligible participants").
Rationale: The protocol was updated to clarify some of the additional AE summaries presented. 
The subgroup analysis was added in line with the analysis populations used for clinical function 
and pharmacodynamic endpoints. 
Section 16.2.5.2, Methods of Analysis
Change: Amended statistical methodology to be consistent with study's Statistical Analysis Plan
Now reads: 
The quality of life measures will be analyzed using a MMRM with baseline disease duration 
since symptom onset, baseline value, and use of riluzole or edaravone as covariates an 
ANCOVA with MI with fixed effect for treatment and covariates for corresponding 
baseline value, baseline disease duration since symptom onset and use of riluzole or 
edaravone.  Overall treatment differences across visits and The treatment difference at Week 28 
Day 197 will be derived from the model.  Treatment differences at other visits will also be 
derived from the model for exploratory purpose. Nominal p-values will be presented.
Rationale: ANCOVA with multiple imputation is specified as the analysis of quality of life 
endpoints instead of MMRM to provide a more robust method for handling missing data.
Section 16.2.6, Interim Analyses


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Change: Specified that no interim analysis will be performed.
Now reads: 
An interim efficacy analysis may be performed.  The specifics around the optional interim 
analysis will be detailed in the statistical analysis plan.  In order to maintain the treatment blind, 
an independent unblinded team not to be involved in the conduct of the study after unblinding 
will perform the interim analysis.   The unblinded team will present the unblinded interim 
analysis to the IDMC.  There will be no interim analysis performed.
Rationale: No interim analysis will be conducted due to potential impact to study power with 
minimal opportunity to accelerate study timelines.
This change also affects Section 9.3, Blinding Procedures.


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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL
Changes to the protocol are presented chronologically.  New text is shown in bold type; deleted 
text is shown with a strikethrough.
Section 1.1, Synopsis
The synopsis was revised to reflect changes made throughout the protocol.
Section 4.2, Schedule of Activities
Change: Footnote 9 in Table 3 was clarified to specify that the diary/eDiary will be completed 
only for days when the participant uses mechanical ventilation.
Now reads:
9 Participants will use a diary/eDiary to record ventilation use. The diary/eDiary should be 
completed only for days when the participant uses mechanical ventilation. This 
diary/eDiary will be reviewed with study site staff at each visit.
Rationale: Clarification
Section 8.2.1, Inclusion Criteria
Change: The nomenclature for the disease progression subgroups (previously "fast progressors" 
and "non-fast progressors") was modified to more accurately represent the population enrolled. 
Now reads:
3. Weakness attributable to ALS and a confirmed SOD1 mutation. 
a.
SOD1 mutation must be confirmed by the central reader based on the sample 
obtained during the Screening Visit; subjectsparticipants with an SOD1 mutation 
interpreted by the central reader to be pathogenic or likely pathogenic will be eligible.
b. Additionally: 

Fast progressor criteria Prognostic enrichment criteria for rapid disease 
progression (subjectsparticipants may be eligible based on 1 of the following 2 
criteria) [Hamidou 2017; Proudfoot 2016]:
a.
One of the following SOD1 mutations and a prerandomization ALSFRS-R 
slope decline of ≥ 0.2 per month (calculated as [48-baseline score]/time 
since symptom onset):
p.Ala5Val, p.Ala5Thr, p.Leu39Val, p.Gly42Ser, p.His44Arg, p.Leu85Val, 
p.Gly94Ala, p.Leu107Val, and p.Val149Gly  


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OR
b. SOD1 mutation other than those listed in item ‘a.’ with prerandomization 
ALSFRS-R slope decline of ≥ 0.9 per month (calculated as [48-baseline 
score]/time since symptom onset)

Non fast progressor criterion Criteria for all other eligible participants: SOD1 
mutation other than those listed in item ‘a.’ (no ALSFRS-R slope decline 
requirement).
4. For fast progressors participants who meet prognostic enrichment criteria for rapid 
disease progression, SVC ≥ 65% of predicted value as adjusted for sex, age, and height 
(from the sitting position).  For non fast progressors all other eligible participants, SVC 
≥ 50% of predicted value as adjusted for sex, age, and height (from the sitting position).
Rationale:
The primary analysis population was enriched, based on SOD1 mutation type and 
prerandomization ALSFRS-R slope decline, for participants more likely to have rapid disease 
progression during the study. The terminology used to describe this population was changed 
from "fast progressors" to "participants who met prognostic enrichment criteria for rapid disease 
progression" to more accurately reflect the population enrolled. Consistently, the terminology for 
the broader population enrolled (previously "non-fast progressors") was updated to "other 
eligible participants." No changes have been made to the criteria to define either subgroup. 
This change also affects Sections 7.1.3, Part C: Pivotal; 9.2, Randomization and Registration of 
Participants; 16.2.1.1, Analysis Population, and 16.2.7, Sample Size Considerations.
Section 6.2.2, Secondary Objective
Change: Added biomarker effects to the secondary objective.
Now reads: The secondary objective is to evaluate the safety, tolerability, and PD, and 
biomarker effects of BIIB067 administered to adult participants with ALS and a confirmed 
SOD1 mutation.
Rationale: Updated to clarify that biomarker effects are also a secondary objective.
Section 6.2.2.1, Safety/Tolerability Endpoint
Change: Added “secondary” to the endpoint.
Now reads: The secondary safety/tolerability endpoint is the incidence of AEs and SAEs.
Rationale: Clarification.


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Section 6.2.2.2, Pharmacodynamic Endpoint
Change: Specified that the change from baseline in total SOD1 protein concentration in CSF is a 
secondary PD endpoint.
Now reads: The secondary PD endpoint is the change from baseline in total SOD1 protein 
concentration in CSF
Rationale: Updated to reflect that total SOD1 protein concentration in CSF will be tested as a 
secondary endpoint.
Section 6.2.2.3, Biomarker Endpoint
Change: The key secondary biomarker and matrix were changed.
Now reads: The secondary biomarker endpoint is the change from baseline in p NFH NfL 
concentration in CSF plasma.
Rationale: Updated to reflect that plasma NfL will be tested as a key secondary (biomarker) 
endpoint. Plasma NfL was selected given the potential utility of a blood-based biomarker in the 
future, along with assay characteristics. Plasma NfL will be evaluated on the Siemens 
Healthineers NfL assay which has good analytical performance and utilizes a fully automated 
instrument.
Section 6.2.3.2, Additional Biomarkers
Change: Clarified additional biomarkers to be measured in serum, plasma, and/or CSF.
Now reads:

Blood (serum) and CSF concentrations of NFLNfL

Blood concentration (plasma, serum) and/or CSF concentrations of pNF-HpNfH
Rationale: Clarification.
Section 7.1.3, Part C: Pivotal
Change: Updated to clarify that a Safety Follow-up (Alternative EOS) Visit should occur when 
enrollment in the LTE study is delayed.
Now reads:
For subjects participating in Part C (Pivotal) and continuing (uninterrupted) in the LTE study 
(233AS102), the study duration will be approximately 32 weeks. This will include up to a 
4-week screening period, a 24-week treatment period (consisting of 3 loading doses of BIIB067 
administered approximately once every 2 weeks, followed by 5 maintenance doses of BIIB067 


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administered approximately once every 4 weeks), and an EOS Visit at Week 28 (4 weeks after 
the last dose). After completing the EOS visit, subjects will be considered study completers and 
they will have the option to participate in the LTE study (233AS102). This will be done without 
unblinding to subject’s treatment group.
For subjects who do not roll over into the LTE study, the duration will be approximately 36 
weeks, as the subjects will have an additional safety follow up visit at Week 32 (8 weeks after 
the last dose) [either in person or by telephone contact]. End of study date is the last visit or 
contact with the subject.
For participants in Part C (Pivotal), the study duration will be approximately 32-36 weeks 
including a 4-week screening period, a 24-week treatment period (3 loading doses 2 weeks 
apart followed by 5 maintenance doses 4 weeks apart), and a 4- to 8- week FU period as 
follows:

Part C participants who enroll (uninterrupted) in the LTE study (233AS102): 
Week 28 Visit will serve as EOS Visit

Part C participants with delays between their Week 28 Visit and enrollment in 
the LTE study: a Safety FU (Alternative EOS) Visit will be conducted (either in 
person or by telephone contact) to collect AEs, SAEs, and concomitant 
medications or procedures. This Safety FU (Alternative EOS) Visit can be 
performed at Week 32 or prior to (within 2 days) enrollment in the LTE, 
whichever comes first.

Part C participants who do not enroll in the LTE study: Week 32 Visit will serve 
as EOS Visit (either in person or by telephone contact)
Rationale: Updated to clarify that a Safety FU (Alternative EOS) Visit should occur at Week 32 
or prior to (within 2 days) enrollment in the LTE study, whichever is first, when there is a delay 
between the Week 28 visit and enrollment in the LTE study. This follow-up visit will ensure 
continuity of monitoring (adverse events, serious adverse events, concomitant medications, 
concomitant procedures) through entry in the LTE or for at least 8 weeks after the last dose of 
study treatment. 
This change also affects Section 4.1, Study Schematic; Section 4.2, Schedule of Activities; 
Section 7.3.3.3, Part C: Pivotal; Section 7.5, End of Study; and 15.3.1 Adverse Events.
Section 12, Study Treatment Management
Change:  Replaced “supersedes” with “aligns with”
Now reads: 
The DHA supersedesaligns with all other references, (e.g., protocol)including the protocol.


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Rationale: Wording was modified to align with updates to the protocol template. 
Section 18.3, Monitoring of the Study
Change: Implemented remote evaluation of data and source documents. 
Now reads:
The Investigator must permit study-related monitoring by providing direct access to source data 
and to the subjects’participants’ medical histories. Source data must be attributable, legible, 
contemporaneous, original, accurate, and complete. Changes to source data must be 
traceable, not obscure the original entry, and be explained if necessary (e.g., with an audit 
trail). The Investigator should maintain a record of the location(s) of essential documents.
The Clinical Monitor will visit the Investigator at regular intervals during the study and after the 
study has completed, as appropriate. During these visits, CRFs and supporting documentation 
related to the study will be reviewed and any discrepancies or omissions will be resolved.  
Remote evaluation of data (centralized monitoring) and remote verification of source 
documentation may also be conducted and reported as defined in the monitoring plan.
Monitoring visits must be conducted according to the applicable ICH and GCP guidelines to 
ensure protocol adherence, quality of data, study treatment accountability, compliance with 
regulatory requirements, and continued adequacy of the investigational site and its facilities.
Rationale: Remote evaluation of data and source documents is being implemented to allow the 
sponsor and CRO to continue to provide oversight to site performance and ensure overall patient 
safety and data integrity. This process is being implemented because several sites/institutions 
have restricted on -site access for the CRO monitors during this ongoing COVID-19 pandemic.
Section 19.1, Public Health Emergencies
Change: Added contingency plan in the event of site closure, travel restrictions, or other events 
resulting from a public health emergency. 
Now reads:
19.1, Public Health Emergencies
In the event of a public health emergency that results in site closure, travel restrictions, 
and/or the study being deprioritized at the site such that clinic visit(s) cannot occur, a 
protocol deviation would be incurred for any deviation from the protocol-specified visits 
and assessments, with additional notation that this protocol deviation is due to the public 
health emergency. If a protocol-specified clinical visit cannot occur due to a public health 
emergency, the following mitigating options should be pursued, in order of preference (in 
which the highest preference option that is feasible should be done): 1) transfer to another 
active study site that is open, 2) home visit, 3) telemedicine visit (e.g., by telephone or web 
conference), and 4) local laboratory visit. These mitigating options only apply in the setting 






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SUMMARY OF MINOR CHANGES TO THE PROTOCOL
The following minor changes were made to the protocol, as appropriate:

The version number and date were updated throughout the protocol.

A new signatory’s name and title were added.  The previous signatory’s name and 
title were removed.

Section 2, List of Abbreviations, was updated.

Replaced “subject” with “participant” throughout the protocol (with exception of the 
title).

Deleted “tertiary/” preceding exploratory objectives.

The abbreviation for neurofilament light was changed from “NFL” to NfL” and the 
abbreviation for phosphorylated axonal neurofilament heavy chain was changed from 
“pNF-H” to “pNfH.”

Differentiated between SOD1 gene/mutation and total SOD1 protein.

Abbreviations were deleted from the footnotes in tables and figures and added to the 
List of Abbreviations to align with the updated protocol template

The expanded forms of abbreviations were deleted at first use to align with the 
updated style guide

Replaced “population outside the mITT” with “non-mITT population.”

Typographical errors and formatting were corrected.
            


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LIST OF ABBREVIATIONS
AE
adverse event
ALS
amyotrophic lateral sclerosis
ALSFRS-R
Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised
ANCOVA
analysis of covariance
CAFS
Combined Assessment of Function and Survival
CRF
case report form
CRO
contract research organization
CSF
cerebrospinal fluid
CSR
clinical study report
C-SSRS
Columbia Suicide Severity Rating Scale
DHA
Directions for Handling and Administration
EOS
end of study
FU
follow-up
GCP
Good Clinical Practice
HHD
handheld dynamometry
ICH
International Council for Harmonisation
IDMC
independent data monitoring committee
ITT
intent-to-treat
JRT
joint rank test
LTE
long-term extension
MedDRA
Medical Dictionary for Regulatory Activities
MI
multiple imputation
mITT
modified intent-to-treat
MMRM
mixed model for repeated measures
MMSE
Mini-Mental State Examination
NfL
neurofilament light chain
PD
pharmacodynamic(s)
PK
pharmacokinetic(s)
pNfH
phosphorylated axonal neurofilament heavy chain
SAE
serious adverse event
SOD1
superoxide dismutase 1
SVC
slow vital capacity


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TEAE
treatment-emergent adverse event
UN
unstructured covariance
VAFS
ventilation assistance-free survival


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1
Biogen MA Inc.
225 Binney Street
Cambridge, MA  02142
United States
Biogen Idec Research Limited
Innovation House
70 Norden Road
Maidenhead Berkshire
SL6 4AY
United Kingdom
______________________________________________________________________
AMENDMENT SUMMARY
Biogen Protocol 233AS101
A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics 
of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral Sclerosis and Confirmed 
Superoxide Dismutase 1 Mutation
Version 7
Date: 30 September 2019
EUDRA CT Number: 2015-004098-33
Version 7 of the protocol has been prepared for this amendment, which supersedes Version 6, 
dated 19 September 2019.




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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL
No major changes are being made in this amendment.


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SUMMARY OF MINOR CHANGES TO THE PROTOCOL
The following minor changes were made to the protocol, as appropriate:

The version number and date were updated throughout the protocol.

Section 4.2, Schedule of Activities (Table 3 – Schedule of Activities: Part C 
[Pivotal]), 
 

Section 6.2.3.2, Additional Biomarkers, sub-bullet blood and CSF concentrations of 
pNF-H was updated to blood concentration of pNF-H, as change in CSF 
concentration of p-NFH is already covered as a biomarker endpoint under Section 
6.2.2.3 (Biomarker Endpoint).

Typographical errors and formatting were corrected.


CONFIDENTIAL
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Biogen MA Inc.
1
Biogen MA Inc.
225 Binney Street
Cambridge, MA  02142
United States
Biogen Idec Research Limited
Innovation House
70 Norden Road
Maidenhead Berkshire
SL6 4AY
United Kingdom
______________________________________________________________________
AMENDMENT SUMMARY
Biogen Protocol 233AS101
A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation
Version 6
Date: 19 September 2019
EUDRA CT Number: 2015-004098-33
Version 6 of the protocol has been prepared for this amendment, which supersedes Version 5 
dated 20 December 2018.


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PRIMARY REASON FOR AMENDMENT
The primary reason for this amendment to Protocol 233AS101 is to describe the changes to the 
primary endpoint and statistical methodology, sample size considerations, and inclusion of an 
optional interim efficacy analysis for Part C (Pivotal) of the study. 
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 6.2.1., Primary Objective
Now reads:
6.2.1.1.
Primary Efficacy Endpoint
The primary efficacy endpoint of Part C is the postrandomization slope of the ALSFRS R score 
measured change from baseline to Week 28 in the ALSFRS-R total score.
Section 16.2.1.2.1., Analysis of the Primary Efficacy Endpoint
Now reads: 
The primary efficacy endpoint is the postrandomization slope of ALSFRS R scores measured 
from baseline to Week 28.  The postrandomization ALSFRS R score over all time points change 
from baseline to Week 28 in the ALSFRS-R total score, which will be analyzed using the 
joint rank methodology to account for mortality [Berry 2013].  This joint ranking 
procedure allows for a statistical test of the treatment effect on the ALSFRS-R score over 
all time points total score while accounting for loss of data due to deaths. In this analysis, a 
subject’s Combined Assessment of Function and Survival (CAFS) score will be calculated 
by comparing each subject to every other subject in the study, resulting in a score of +1 if 
the outcome was better than the subject being compared, -1 if worse, and 0 if the same.  
The subject’s score will then be calculated by summing their comparison to all the other 
subjects in the study. 
For example, if 2 subjects complete the study up to Week 28, their comparison score will be 
based on the change from baseline in ALSFRS-R total score at Week 28.  A subject who 
dies will rank lower than any subject who completes the study up to Week 28.  Two 
subjects who both die will be ranked based on the time of death, with a longer time to death 
corresponding to a higher rank.  Hence, in general, these comparisons will result in 
subjects who die being assigned the worst scores and ranked according to time of death.  
Subjects who survive and complete the study will be ranked more favorably than subjects 
who die.


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The ranked scores will be analyzed using an analysis of covariance model with treatment 
included as a fixed effect and adjusted for the following covariates: baseline disease 
duration since symptom onset, baseline ALSFRS-R total score, and use of riluzole (yes or 
no), and use of edaravone (yes or no with yes including the use of both edaravone and 
riluzole).  The primary inference will be based on the mITT population. The treatment 
comparison will be based on a 2-sided α level of 0.05. 
If there are insufficient number of deaths, the change from baseline in ALSFRS-R total 
score will be analyzed using a mixed model for repeated measures (MMRM) with fixed effect 
for treatment, time (as a continuous categorical variable), treatment by time interaction, and 
adjustment for baseline ALSFRS-R score, baseline ALSFRS-R score by time interaction,
baseline disease duration since symptom onset, use of riluzole (yes or no), and use of riluzole or 
edaravone (yes or no with yes including the use of both edaravone and riluzole).  An 
unstructured covariance (UN) matrix will be used to model the within-subject variance-
covariance errors If the unstructured covariance structure matrix results in a lack of convergence, 
the first order autoregressive covariance structure will be used.  The Kenward Roger 
approximation will be used to estimate the denominator degrees of freedom.  The primary 
inference will be based on the estimated treatment by time interaction in the mITT population.  
The estimated difference in slope of decline between BIIB067 and placebo, and the associated 
95% confidence interval, will be derived from the model.  The treatment effect will be assessed 
at a 1 sided α level of 0.05 (or 2 sided α level of 0.10).  In addition, as a supportive analysis, the 
slope of each individual subject will be derived using simple least square estimate, and treatment 
comparison using the Mann Whitney test, based on ranked data, will be made.  As a further 
sensitivity analysis, the slope of decline in 92 days observed in subjects from Part B who 
received placebo or BIIB067 100 mg will be pooled with Part C slopes over 92 days, and the 
Mann Whitney test will be performed on the pooled data.  The treatment effect in the overall ITT 
population will also be assessed similarly.  The ALSFRS R score will be set to 0 upon 
occurrence of death.  The primary inference will be based on the treatment comparison at 
Week 28. A 2-sided α level of 0.05 will be used. 
Sensitivity analyses of the primary efficacy endpoint will be specified in the statistical
analysis plan.
Rationale for Section 6.2.1 and Section 16.2.1.2.1: The primary efficacy endpoint was revised
from ALSFRS-R slope to total score (change from baseline to Week 28) and will be analyzed via 
a joint-rank analysis that combines the ALSFRS-R score and survival time. This approach 
minimizes the dependency on linearity assumptions (of the ALSFRS-R slope decline) and 
enables a robust mechanism for accounting for missing data due to death.


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Section 16.2.7., Sample Size Considerations
Now reads:
For Part C, up to 60 subjects approximately 99 subjects will be enrolled in a single cohort 
randomized, with 40 approximately 66 subjects administered BIIB067 100 mg and 20 
approximately 33 subjects administered placebo in a 2:1 ratio.
This sample size for Part C is selected primarily based on the primary endpoint, joint rank test 
combining the slope of decline Week 28 change from baseline in ALSFRS-R and mortality, 
in the mITT population (fast progressor group, N = 60). The observed results from an interim 
analysis of BIIB067 100 mg from Study 233AS101 in the fast progressor subject group as well 
as the observed ALSFRS-R decline in subjects who received placebo in a similar fast progressor 
ALS population with SOD1 mutation [Benatar 2018] are the basis of assumed treatment effect 
and the variability.  The observed mean ± SD of the slope of decline in the historical placebo 
data [Benatar 2018] was 3.2 ± 2.5 per month (markedly more rapid than that in the overall ALS 
population).  The interim data of a very small cohort in Study 233AS101 suggested a treatment 
difference between BIIB067 100 mg and placebo of 5.8 per month in favor of BIIB067 100 mg 
with an estimated pooled SD of 1.4 and an estimated mean decline in the active group of 0.8 per 
month.  Given the small sample size for the treatment comparison in Study 233AS101, a 
conservative assumption of a treatment difference of 2.4 per month (the difference between 
historical placebo mean and observed mean of BIIB067 100 mg in Study 233AS101) and a SD 
of 2.5 (from historical data) was made.  With a 2:1 randomization ratio, a sample size of 
36 subjects in the fast progressor population (mITT population) would provide the study with 
85% power at 1 sided α of 0.05 to detect such treatment differences.  Because events of death or 
permanent ventilation assistance have been factored in the analysis, no sample size overage is 
planned for missing values. Subjects from both datasets were matched with the criteria for a 
fast progressor specified in this protocol for Part C (i.e., one of the protocol-defined SOD1 
mutations and a pre-randomization ALSFRS-R decline slope ≥0.2 per month or a pre-
randomization ALSFRS-R decline slope ≥0.9 with SOD1 mutation NOT on the 
protocol-defined list). This resulted in a total of 12 placebo control fast progressors (8 from
the historical placebo data [Benatar 2018] and 4 from Study 233AS101) and 4 fast progressors 
treated with BIIB067 100 mg from interim data of a very small cohort in Study 233AS101. 
The observed mean slope of decline was -3.83 for the matched placebo subjects and -0.74 
for the matched BIIB067 100 mg subjects, with a pooled SD of 3.166.  In the 12 matched 
fast progressors on placebo, there was 1 death and 2 subjects with PAV less than 6 months 
but none in the BIIB067 100 mg potential fast progressors. Based on this and overall 
survival data in fast progressors from the literature on subjects with an A4V SOD1 
mutation, the survival at Week 28 was assumed to be 82% in the placebo control and 90% 
in the BIIB067 100 mg group. 
Under the above assumptions, with N = 60 fast progressors and a two-sided significance 
level of 0.05, the joint rank test gives 84% power. Because events of death have been 
factored in the analysis, no sample size overage is planned for missing values. 


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For the subject population outside of the mITT population, the primary focus will be on the PD 
endpoint, CSF SOD1 concentration, due to their likely slow clinical function decline as this 
population is anticipated to have a slower decline in clinical function compared to the 
mITT population. A sample size of 16 26 subjects in this group the treated group and 
13 subjects in the placebo group for the population outside of the mITT would provide 80%
97% power to detect a 19% 25% reduction in CSF SOD1 from baseline within group in the 
treated group, with an assumed SD of 0.28 0.216 (in natural log scale), as observed in this 
population in Study 233AS101 compared to the placebo group.
Rationale: The sample size for Part C of the study was increased to approximately 99 subjects 
(increased from up to 60 subjects) based on the following changes: 

Revised primary efficacy endpoint of change in ALSFRS-R total score from baseline to 
Week 28 analyzed via the joint-rank methodology

Two-sided alpha of 0.05 for the primary analysis

Revised survival assumptions based on further review of natural history data and data 
from an interim analysis of Part B of this study (82% survival in the placebo control 
group and 90% survival in the BIIB067-treated group)
Under these assumptions, approximately 60 subjects (increased from 36) are needed in the mITT 
population (fast progressors) to achieve approximately 84% power. The target sample size for 
the non-fast progressor population was increased to approximately 39 subjects (increased from 
24) to enable adequate power to detect a statistically significant reduction in CSF SOD1 
concentrations.
Also, the assumptions for the sample size needed for the population outside the mITT were 
updated based on current results from the Part B of this study (233AS101).
This change also affects Section 5.4, Study Rationale and Section 7.1, Study Overview.
Section 16.2.6, Interim Analyses
Now reads:
In Part C of the study, a blinded sample size re estimation may be conducted when 
approximately 18 subjects in the fast progressor population complete Day 169 assessments of 
ALSFRS R or have an outcome of death or permanent ventilation assistance.  At this interim 
timepoint, the SD for the primary endpoint will be estimated based on the blinded data.  The 
sample size of the fast progressor group may be increased to up to 60 (potentially increasing the 
total sample size to approximately 80 subjects) if the SD is estimated to be ≥3.  As this is based 
on blinded data, the type I error rate is maintained.


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An interim analysis may be performed. The specifics around the optional interim analysis 
will be detailed in the statistical analysis plan. In order to maintain the treatment blind, an 
independent unblinded team not to be involved in the conduct of the study after unblinding 
will perform the interim analysis. The unblinded team will present the unblinded interim 
analysis to the IDMC. 
A futility analysis may be performed at the interim.  The futility criteria will be prespecified in 
the analysis plan, and if conducted, all necessary procedures to safeguard the integrity of the 
blind will be set in place.  No early stopping for efficacy will be made at this interim analysis.
Section 7.1.3, Part C: Pivotal
Now reads: 
…
…
In the event of a decision by the Study Sponsor to terminate the study earlier on the 
grounds that conducting a placebo-controlled study is no longer deemed ethical based on 
the assessment of risk-benefit of Study 233AS101, all subjects will be invited for an EOS 
visit, during which all Week 28 assessments will be conducted.  For subjects not entering 
the LTE study or in the event the study is stopped early, there will be an additional safety 
follow-up visit 8 weeks after the last dose of study treatment.
Rationale for Section 16.2.6 and Section 7.1.3: An optional interim efficacy analysis has been 
included to enable the earliest opportunity to detect a clinically meaningful effect and potential to 
minimize placebo exposure should the study be terminated early due to a positive interim 
analysis.  Correspondingly, the text around futility analysis was removed.
This change also affects Section 4.2 (Table 3), Schedule of Activities: Part C (Pivotal); and 
Section 9.3, Blinding Procedures.


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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL
Changes to the protocol are presented chronologically. New text is shown in bold type; deleted 
text is shown with a strikethrough.
Section 3, Synopsis
The Synopsis was revised to reflect changes made throughout the protocol.
Section 6.2.1.2, Secondary Efficacy Endpoints; Section 6.2.3, Tertiary/Exploratory Objectives; 
and Section 6.2.3.3, Quality of Life Endpoints
Change: The Combined Assessment of Function and Survival (CAFS) and change from baseline 
in ALSFRS-R total score were removed as secondary endpoints. The assessments related to 
quality of life assessments were moved from the secondary efficacy endpoints section to the 
exploratory endpoints section.
Now reads: 
6.2.1.2.
Secondary Efficacy Endpoints
The secondary efficacy endpoints are as follows:

Combined assessment of function and survival (CAFS) up to Week 28.

Change from baseline to Week 28 in ALSFRS R score.

Change from baseline to Week 28 in SVC.

Ventilation assistance-free survival (VAFS), which is defined as the time to the 
earliest occurrence of 1 of the following events:

Death. 

First use of non invasive ventilation (NIV) for ≥22 hours per day for 
≥10 consecutive days. Permanent ventilation (≥22 hours of mechanical 
ventilation (invasive or noninvasive) per day for ≥21 consecutive days).
First use of permanent assisted ventilation (PAV) for ≥22 hours per day for 
≥7 consecutive days.

Overall survival.






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interaction, baseline disease duration since symptom onset, baseline ALSFRS R score, and use 
of riluzole or edaravone as covariates.
The second and third secondary efficacy endpoints, ALSFRS R and SVC, respectively, will be 
analyzed using a MMRM with baseline disease duration since symptom onset, baseline value 
(ALSFRS R and SVC, respectively), and use of riluzole or edaravone as covariates.  The 
ALSFRS R score and SVC will be set to 0 upon occurrence of death or permanent ventilation 
assistance. Overall treatment difference across visits and treatment difference at Week 28 will be 
derived from the model. Treatment differences at other visits will also be derived from the model 
for exploratory purpose.  
The fourth second and fifth third secondary efficacy endpoints, VAFS and overall survival, 
respectively, will be analyzed as time to event. Kaplan-Meier estimates of the cumulative 
probability of event occurrence over time will be determined. Treatment comparison will be 
based on a Cox proportional hazards model with baseline disease duration since symptom onset, 
baseline ALSFRS R score, and use of riluzole or edaravone as covariates stratified log rank 
test.  A Cox regression model will be used to obtain the hazard ration and 95% confidence 
intervals for each of these endpoints.
The muscle strength as measured by HHD will be summarized by individual muscles and 
megascore. The megascore will be analyzed using a MMRM with fixed effect for treatment, 
time (as a categorical variable), treatment by time interaction and adjustment for baseline 
HHD megascore, baseline HHD megascore by time interaction, baseline disease duration 
since symptom onset, baseline value, and use of riluzole or edaravone. as covariates. The HHD 
megascore will be set to 0 upon occurrence of death or permanent ventilation assistance. Overall 
treatment difference across visits and treatment difference at Week 28 will be derived from the 
model. Treatment differences at other visits will also be derived from the model for exploratory 
purpose.
Rationale:  The analysis for the 2 secondary endpoints of CAFS up to Week 28 and change from 
baseline to Week 28 in ALSFRS-R total score was removed because these endpoints are now 
incorporated into the primary endpoint.
Section 8.2.1, Inclusion Criteria
Change: Criteria for screening values of coagulation parameters to be within normal range was 
removed.
Now reads: 
…
8.
Screening values of coagulation parameters including platelet count, INR, PT, and APTT 
should be within normal ranges.  Coagulation tests may be repeated once if, in the opinion of the 


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Investigator, values of the initial tests are only slightly out of range.  Subjects with nonclinically 
significant and stable out of range values may be eligible to enroll in the study at the discretion 
of the Investigator.  (For normal ranges, please refer to the study reference guide).  
…
Rationale: Considering the stage of development of BIIB067 in this study and in the overall 
program, this criterion of coagulation parameters values to be in normal range is not required and 
was removed. The original criterion was more appropriate for early phase clinical studies.
Section 8.2.2, Exclusion Criteria
Change: Details for hepatitis C infection screening for Part C were updated based on the current 
protocol template guidelines. 
Now reads: 
Candidates will be excluded from study entry if any of the following exclusion criteria exist at 
Screening, or at the timepoint specified in the individual criterion listed:
1
History of or positive test result for human immunodeficiency virus.
2
History of, or positive test result at Screening, for hepatitis C virus antibody. 
2
Current hepatitis C infection (defined as positive hepatitis C virus [HCV] antibody 
and detectable HCV ribonucleic acid [RNA]). Subjects with positive HCV antibody 
and undetectable HCV RNA are eligible to participate in the study (United States 
Centers for Disease Control and Prevention).
3
Current hepatitis B infection (defined as positive for HBsAg and/or anti-HBc).  Subjects 
with immunity to hepatitis B from previous natural infection (defined as negative 
HBsAg, positive IgM anti-HBc, and positive anti-HBcHBs) or vaccination (defined as 
negative HBsAg, negative anti-HBc, and positive anti-HBs) are eligible to participate 
in the study.
…
15 Anticipated need, in the opinion of the Investigator, for administration of any antiplatelet 
or anticoagulant medication (e.g., clopidogrel) for 7 days that cannot be safely held
before and/or 48 hours after an LP procedure according to local or institutional 
guidelines and/or Investigator determination.
Rationale: Additional guidance text was provided to clarify the exclusion criterion of current 
hepatitis C infection. The hepatitis B criterion was reworded for accuracy and clarity as the text 


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in the current protocol (version 5) was not clear or completely accurate. These changes in 
hepatitis B and hepatitis C criteria are in alignment with the current protocol template guidance. 
Because study drug administration will occur via lumbar puncture, care must be exercised in the 
use of antiplatelet or anticoagulant medication. However, the criterion has been updated to allow 
for the local standard of care to be used, accounting for the many different indications, 
medications, and individual patient situations that may be relevant. 
The change in exclusion criterion 15 also affects Section 11.3.1.2, Disallowed Concomitant 
Therapy.
Section 9.1, Screening and Enrollment
Change: Rescreening criteria for subjects who fail to complete Day 1 Visit within 28 days of 
their screening assessments during Part C were added. 
Now reads: Subjects (or their legally authorized representative [e.g., spouse], where applicable) 
must provide informed consent before any screening tests are performed (see Section 17.3).  
When a subject signs the informed consent form (ICF), that subject is considered to be enrolled 
in the study.  Participating study sites are required to document all screened candidates initially 
considered for inclusion in this study.  If a subject is excluded from the study, the reasons for 
exclusion will be documented in the subject’s source documents and on the screening log.
Eligible For Part C (Pivotal) subjects who are not able fail screening can be rescreened up to 
complete one time at the Day 1 Visit within 28 days discretion of their the Investigator.
All screening assessments (Screening Visit 2would need to be repeated during rescreening 
except for Parts A and B) may be rescreened.the following:

Follicle-stimulating hormone (FSH) level in female subjects with post-menopausal 
state confirmed by level obtained in previous screening for Part C of this study

Confirmation of SOD1 mutation by the central reader if available from previous 
screening for Part C (Pivotal) of this study
Rationale: It was clarified that rescreening during Part C of the study is allowed at the discretion 
of the Investigator, and the assessments that need not be performed during rescreening are listed.


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Section 4.2, Schedule of Activities
Change: Table 3, Schedule of Activities: Part C (Pivotal) was updated to revise the frequency of Mini-Mental State Examination
(MMSE) testing and to reflect changes in the assessment timepoints for 12-lead electrocardiogram (ECG) and blood sample for 
plasma pharmacokinetic (PK) evaluation.
Now reads: 
Screening1
Loading Dose Treatment Period
Maintenance 
Treatment Period
Follow Up 
Visit2 EOS 
Visit2,3 
(All Subjects)
End of Study or 
Telephone Call Safety 
FU Visit for Subjects 
not Continuing in the 
LTE Study4
(In Person or 
Telephone Contact)
Baseline5
(Dose 1)
Week 2
(Dose 2)
Week 4
(Dose 3)
Week 8, 12, 16, 20, 
and 24
Week 28 OR 
(4 Weeks After 
Last Dose)
Week 32 OR
(8 Weeks After Last 
Dose)
Tests and Assessments4 5
Day
-28 to
Day -1
Day 1
(±3 days)
Day 15
(±3 days)
Day 29
(±3 days)
Days 57, 85, 113, 141, 
and 169 (±3 days)
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days)
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days)
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
Pre 
dose
LP
Post 
dose
12-Lead ECG 12,14 14,16
X
X
X17
X11
X17
X
Limited Neurological 
Examination (including 
MMSE)12,1414, 19
X
X
X
X
X
X
X
X
X
X
MMSE
X
X
X
X11
X11
X
5 All visits are expected to take place on site unless subjects are unable to travel to the site; then, a home visit may be possible at the discretion of the 
Investigator.
...
...
11To be performed on Week 12 (Day 85) and Week 24 (Day 169) only.


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…
14Assessment must occur on the day of dosing.
...
16Triplicate 12-lead ECGs will be obtained after the subject has rested in a supine position for at least 10 minutes.  All ECGs will be centrally read; ECGs will be 
read by the Investigator at collection, and then sent to a central ECG reader for further evaluation and to confirm eligibility at Screening.  The first ECG will be 
interpreted, and the last 2 will be checked for consistency and quality.
Rationale: In Part B of the study no significant safety findings were noted on the MMSE, so the frequency of the MMSE assessment 
was reduced to every 3 months during the treatment period in Part C of the study
Considering the median plasma Tmax of 3 hours (range 1 to 24 hours) for the 100 mg cohort of Part B and to support a potential waiver 
for Thorough QT (TQT) analysis, it was clarified that at the Baseline Visit, the ECGs should be assessed just prior to drawing PK 
blood samples at 2, 4, and 6 hours postdose. It was also clarified that blood samples for PK will be collected predose at all timepoints 
and postdose only at Day 1 and Day 85.








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
Typographical errors and formatting were corrected.


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______________________________________________________________________
AMENDMENT SUMMARY
Biogen Protocol 233AS101
A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation
Version 5
Date: 20 December 2018
EUDRA CT: 2015-004098-33
Version 5 of the protocol has been prepared for this amendment, which supersedes Version 4.


Protocol 233AS101, Version 5
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PRIMARY REASON FOR AMENDMENT
The primary reason for this amendment to Protocol 233AS101 is to include a third part (Part C
[Pivotal]) of approximately 60 subjects (2:1 randomization ratio of BIIB067:placebo) to assess 
the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of BIIB067 at 
100 mg. Part C will be conducted over a 4-week screening period, 24-week treatment period and 
4-week follow-up period. This inclusion of Part C also warrants a change in the phase of 
development of the study, the title of the protocol to accurately reflect study design and the 
objectives and endpoints. 
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 5.4, Study Rationale
Now reads:
Parts A (SAD) and B (MAD)
Pharmacology and toxicology data in rats, mice, and monkeys indicate that BIIB067 is well 
tolerated.  This Phase 1Parts A and B of the study will evaluate the safety, tolerability, and PK 
profile of a range of single and multiple intrathecal BIIB067 doses from a projected minimal 
pharmacologic dose to either the maximum tolerated dose (MTD) or the highest planned dose of 
100 mg.  MTD for this study is defined as the highest tested dose with a less than 33% 
dose-limiting toxicity (DLT) rate at Day 15.  See Section 7.2.3 for the definition of DLT.
Part C (Pivotal)
Interim analyses of data from subjects in Part B (MAD) Cohorts 5 to 8 treated for 85 days 
were conducted.  Safety analyses of these data suggested that all doses through 100 mg had 
been well tolerated with a safety profile supportive of continued development of BIIB067 in 
ALS subjects.  Preliminary and exploratory analyses of clinical function data (ALSFRS-R, 
vital capacity, and muscle strength) further suggested possible emergence of early clinical 
efficacy signals.  Based on these emerging data from Parts A and B, a randomized, double-
blind, placebo-controlled, pivotal phase (Part C) is designed to assess the efficacy and 
safety of BIIB067 100 mg versus placebo.  Approximately 60 subjects with SOD1-ALS will 
be enrolled and randomized to receive BIIB067 or placebo and treated for 24 weeks.
Rationale: The interim analyses of Study 233AS101 were based on treated subjects in multiple
ascending dose Cohorts 5 to 8 treated for 85 days (pending review of 100 mg data for safety and 
efficacy). Safety analyses of these data suggested that all doses through 100 mg had been well 
tolerated with a safety profile supportive of continued development of BIIB067 in amyotrophic 
lateral sclerosis (ALS) subjects. Preliminary and exploratory analyses of clinical function data 
(Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised [ALSFRS-R], vital capacity, 
muscle strength) further suggest possible emergence of clinical effect. In order to further assess 
the treatment, 60 subjects with superoxide dismutase 1 (SOD1)-ALS will be enrolled and 
randomized to BIIB067 or placebo and treated for 24 weeks duration.
This change also affects the phase of development; the title of the protocol; Section 3, Synopsis; 
Section 4, Study Schematic and Schedule of Activities for Study 233AS101; Section 4.1, Study 




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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL
Changes to the protocol are presented chronologically. New text is shown in bold type; deleted 
text is shown with a strikethrough.
Title Page
Change: The phase of development and protocol title were updated to accurately reflect the 
addition of Part C (Pivotal).
Now reads:
PHASE OF DEVELOPMENT:
1/2/3
PROTOCOL TITLE: A Phase 1, Placebo Controlled, Single and Multiple Ascending Dose
Study to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation
Rationale:  The primary objective of Part C (Pivotal) is efficacy; therefore, the overall phase of 
development of the study and the title of the study were changed to reflect this new objective and 
related endpoints.
Section 3, Synopsis
The Synopsis was revised to reflect changes made throughout the protocol.
Section 5.3.2, Clinical Experience
Change: Added that additional information on the safety, pharmacokinetics, and 
pharmacodynamics for BIIB067 can be found in the Investigator’s Brochure.
Now reads:
This is the first-in-human (FIH) study of BIIB067; therefore, no clinical experience is available 
to date. preliminary safety, PK, and pharmacodynamic (PD) information for BIIB067 can 
be found in the Investigator’s Brochure.  
…
Rationale:
Based on data analysis from Parts A and B of the study, the Investigator’s Brochure has been 
updated to reflect the current safety, pharmacokinetic, and pharmacodynamic information for 
BIIB067. 


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Section 6, Study Objectives and Endpoints
Change: Clarified that the primary objective of Parts A and B was to evaluate the safety, 
tolerability, and pharmacokinetics of BIIB067 in adult subjects with ALS and confirmed SOD1 
mutation.
Now reads:
6.1.
Parts A (SAD) and B (MAD)
6.1. 6.1.1.
Primary Objective and Endpoints
The primary objective of the Parts A and B of this study is to evaluate the safety, tolerability, 
and PK of BIIB067 in adults subjects with ALS and confirmed SOD1 mutation.
6.1.1.1. Primary Endpoints
…
6.1.21. Secondary Endpoints
…
Rationale: Subjects must have both ALS and confirmed SOD1 mutation in order to be enrolled 
into any part of the study.
Section 7.1, Study Overview
Change: Addition of Japan as potential location for sites.
Now reads:
…
The study will be conducted at approximately 1718 sites in the United States, Canada, Japan,
and Western Europe.  
…
Rationale: Adding Japan as an additional country for potential sites in order to enable eventual 
filing for Japan.
Section 8.2.1, Inclusion Criteria
Note: all the inclusion exclusion criteria of Part A and Part B of the study are applicable to 
Part C other than the changes mentioned below.
Change: Inclusion criterion 3 was updated to clarify inclusion of subjects with both non-fast and 
fast progression of disease.
Now reads:
3. Weakness attributable to ALS and confirmed SOD1 mutation at Screening Visit 2 Visit.
Additionally:


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
Fast progressor criteria:
a. One of the following SOD1 mutations and a prerandomization 
ALSFRS-R decline slope ≥0.2 per month (calculated as [48-baseline 
score]/time since symptom onset):
p.Ala5Val, p.Ala5Thr, p.Leu39Val, p.Gly42Ser, p.His44Arg, 
p.Leu85Val, p.Gly94Ala, p.Leu107Val, and p.Val149Gly  
OR
b. SOD1 mutation other than those listed in item ‘a.’ with 
prerandomization ALSFRS-R decline slope ≥0.9 per month 
(calculated as [48-baseline score]/time since symptom onset)

Non-fast progressor criterion: SOD1 mutation other than those listed in item ‘a.’ 
(no ALSFRS-R decline slope requirement).
Rationale: The rate of ALS progression can vary widely across both non-genetic and SOD1 
ALS.  In order to account for non-fast and fast progressor subjects, specific SOD1 mutations and 
pre-slope criteria have been included.
Change: Inclusion criterion 4, a slow vital capacity (SVC) of ≥65% of predicted value for fast 
progressors adjusted for sex, age, and height (from sitting position), was added as an inclusion 
criterion.  SVC≥50% for non-fast progressors was also added. 
Now reads:
4. For fast progressors, SVC ≥65% of predicted value as adjusted for sex, age, and 
height (from the sitting position).  Subjects with stable FVC <50% but ≥45%, whose 
FVC has not declined by more than 5% in the last 6 months may be considered for 
inclusion, at the discretion of the Investigator For non-fast progressors, SVC ≥50% of 
predicted value as adjusted for sex, age, and height (from the sitting position).
Rationale: In Parts A and B of this study, criterion for inclusion was forced vital capacity 
(FVC) ≥50% and study duration was 3 months. In Part C of the study, the duration of treatment 
is 6 months and thus in order to improve the probability of survival through 6 months the use of 
SVC ≥65% instead of FVC ≥50% was added to Part C. SVC is commonly used in ALS studies 
and is easier for patients and sites to perform consistently. 
Change: Inclusion criterion 6 permitting the use of edaravone was added as inclusion criterion 
as long as the subject initiated edaravone ≥60 days (2 treatment cycles) prior to Day 1 and that 
edaravone may not be administered on dosing days.  The use of edaravone or any implanted 
vascular devices was removed as exclusionary criteria.  
Now reads: 
6. If taking edaravone, subject must have initiated edaravone ≥60 days (2 treatment 
cycles) prior to Day 1 and expected to remain at that dose until the final study visit, 


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unless the Investigator determines that edaravone should be discontinued for 
medical reasons, in which case it may not be restarted during the study.  Edaravone 
may not be administered on dosing days of this study.
Rationale: Edaravone is now an approved medication for treatment of ALS in some regions of 
the world in which this study is being conducted. In order to not deprive subjects from an 
approved treatment, use of edaravone is allowed.
This change also affects Section 8.2.2, Exclusion Criteria.
Section 8.2.2, Exclusion Criteria
Change: Exclusion criterion 9 was removed to allow the use of vascular devices. 
Now reads:
9. Presence of any implanted vascular devices.
Rationale: Edaravone is administered via implanted vascular devices, and therefore, the 
inclusion of edaravone as an acceptable concomitant medication warrants the use of implanted 
vascular devices for Part C (Pivotal).
Change: Exclusion criterion 11 was removed to allow subjects with a tracheostomy to enroll. 
Now reads:
11. Tracheostomy.
Rationale: Most subjects with ALS will rely on a tracheostomy at some point, and the use of a
tracheostomy will not interfere with the study drug administration and data analysis of BIIB067. 
Section 13.1, Exploratory Assessments of the Effect of BIBB067 on Clinical Function
Change: Text was included to allow subjects to have a home visit if they are unable to travel to 
the site.
Now reads:
…
All study visits are expected to occur at the site unless the subject is unable to travel to the 
site then a home visit may be possible with Investigator approval.
Rationale: In order to relieve the burden on subjects and continue to collect data, subjects who 
are unable to travel to the site may be able to have a home visit. 
Section 13.1.1, ALS Functional Rating Scale-Revised
Change: Text was clarified to state that a dedicated, blinded staff member will perform the 
ALSFRS-R for a subject. 




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
12 continuous months of natural (spontaneous) amenorrhea without an 
alternative medical cause and a serum follicle-stimulating hormone level 
>40 mIU/mL 

6 weeks after surgical bilateral oophorectomy with or without hysterectomy

Posthysterectomy

Female surgical sterilization (e.g., bilateral tubal ligation) 
For the purposes of the study, highly effective contraception is defined as use of more than 1 of 
the following:
For females:

Established use of oral, injected, or implanted, intravaginal, or transdermal
hormonal methods of contraception.

Placement of an intrauterine device or intrauterine hormone-releasing system.

Male Barrier methods of contraception with use of a spermicide: condom or 
occlusive cap (diaphragm or cervical/vault caps) with spermicidal 
foam/gel/film/cream suppository.  The use of barrier contraceptives should always be 
supplemented with the use of a spermicide.

Sex with a male who has undergone surgical sterilization (with the appropriate 
postvasectomy documentation of the absence of sperm in the ejaculate). (For female 
subjects participating in the study, male sexual partners must have undergone surgical 
sterilization.)
For males:
A vasectomy with negative semen and analysis at follow up.

True abstinence, when this is consistent with the preferred and usual lifestyle of the 
subject, can be considered an acceptable method of contraception based on the 
evaluation of the Investigator who should also take into consideration the duration of 
the clinical trial.  Periodic abstinence (e.g., calendar, ovulation, symptothermal, 
postovulation methods) and withdrawal are not considered acceptable methods of 
contraception.
Pregnancy reporting is described in Section 15.4.1.
Rationale:  Contraception requirements were updated to reflect current accepted contraception 
practices in the parts of the world that the study is being conducted.


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Section 17.4, Subject Data Protection
Change: Added text to state that the race and ethnicity of the subjects will be collected unless 
prohibited by local law.
Now reads:
…
During the study, subjects’ race and ethnicity will be collected (unless the collection is not 
permitted by applicable law or not approved by the governing ethics committee).  These 
data will be used in the analysis of the safety and/or PK profile of the study treatment.  It is 
unknown whether the effects of the study treatment are influenced by race or ethnicity. 
…
Rationale: The race and ethnicity of the subjects are important to capture in order to assess any 
trends in pharmacokinetic data that may be related to race and/or ethnicity.


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SUMMARY OF MINOR CHANGES TO THE PROTOCOL
The following minor changes were made to the protocol, as appropriate:

The version number and date were updated throughout the protocol.

Clarifications were made throughout the protocol in reference to whether information 
pertained to Parts A and/or B.

The Sponsor signatory was updated.

Section 2, List of Abbreviations, was updated.

Section 5, Introduction, a description of the mechanism of action information for 
BIIB067 was added from the Investigator’s Brochure.

Section 8.1.2, Exclusion Criteria; Section 8.2.2, Exclusion Criteria, and 
Section 11.3.1.2, Disallowed Concomitant Therapy, aspirin was removed as an 
excluded concomitant medication. 

Section 8.1.2, Exclusion Criteria and Section 8.2.2, Exclusion Criteria, hepatitis B 
serololigical test abbreviations updated.

Section 9.3, Blinding Procedures, text was added describing end of study unblinding 
procedures.

Section 14.2, Laboratory Safety Assessments, laboratory assessments were updated 
for clarity.

Section 15.1.2, Serious Adverse Event, text was updated to classify a medically 
important event as a serious adverse event (SAE).

Section 15.3.1, Adverse Events, text was added to clarify that at each study visit, the 
Investigator will assess the subject’s adverse events (AEs) and record any new AEs or 
updates to previously reported AEs.

Section 15.3.3, Immediate Reporting of Serious Adverse Events, “Reporting 
Information for SAEs” text was updated to remove text stating that any SAE between 
consent and last follow-up visit must be reported within 24 hours, and that thereafter, 
events should only be reported if related to study treatment. 

Section 15.4.1, Pregnancy, text was added to clarify that a pregnancy is not 
considered an AE and should not be recorded as such and that pregnancy can also be 
reported via email.

Sections 15.4.2, Overdose, and Section 15.6.1, The Investigator, text was added 
indicating that overdose and SAEs may be reported by email. 

Section 16.1.4.2, Methods of Analysis, p75 was added as a potential biomarker for 
analysis. 

Section 19.1.4, Laboratory Assessments, text added to clarify that serum pregnancy 
tests will be analyzed at a central laboratory. 


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
The vendor information was updated to Sponsor information throughout (changed 
from 
 to “Biogen”).

New references were added to the reference list.

Typographical errors and formatting were corrected.


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1
Biogen MA Inc.
225 Binney Street
Cambridge, MA  02142
United States
Biogen Idec Research Limited
Innovation House
70 Norden Road
Maidenhead Berkshire
SL6 4AY
United Kingdom
______________________________________________________________________
AMENDMENT SUMMARY
Biogen Protocol 233AS101
A Phase 1, Placebo-Controlled, Single and Multiple Ascending Dose Study to Evaluate the 
Safety, Tolerability, and Pharmacokinetics of BIIB067 Administered to Adult Subjects with 
Amyotrophic Lateral Sclerosis
Version 4
Date:  29 November 2017
EUDRA CT: 2015-004098-33
Version 4 of the protocol has been prepared for this amendment, which supersedes Version 3.


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PRIMARY REASONS FOR AMENDMENT
The primary reasons for this amendment to Protocol 233AS101 are to 1) add an 8th treatment 
cohort to assess the safety and tolerability of up to 5 doses of BIB067 100 mg, and 2) include the 
option of an interim analysis during Part B (multiple-ascending-dose portion) of the study.
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 7.1.2, Part B: Multiple-Ascending-Dose Evaluation
Now reads:
Part B will be a randomized, double-blind, placebo-controlled, MAD evaluation of up to 34 dose 
levels of BIIB067 administered up to 5 times, over approximately 3 months, to up to 36 48
subjects with SOD1-ALS.  Each dose level will be assessed in cohorts of 12 subjects:  3 subjects 
will be administered placebo, and 9 subjects will be administered BIIB067 at 20, 40, or 60, or
100 mg.  
Rationale:  
Achieving maximum efficacy in the treatment of superoxide dismutase 1 (SOD1) amyotrophic 
lateral sclerosis (ALS) is likely dependent on reducing the levels of the toxic, mutant version of 
SOD1 throughout the central nervous system (CNS) – including the brain (motor cortex) and 
spinal cord. Emerging preliminary pharmacokinetic (PK) data from the ongoing trial indicated 
that the exposure to BIIB067 was less than that predicted preclinically. The purpose of adding a 
higher dose cohort (100 mg) to the trial is to enable a higher exposure to BIIB067, which would 
more effectively reduce SOD1 in the CNS, and is supported by the safety margins from the 9-
month nonhuman primate (NHP) study.
This change also affects Sections 5.4, Study Rationale; 7.1, Study Overview; 7.2.1.2, Part B:  
Multiple Ascending Dose; Figure 3, Dose Escalation Schematic; 9.2, Randomization and 
Registration of Subjects; 11.1.1, BIIB067; and 16.8, Sample Size Considerations.
Section 16.7, Interim Analysis
Now reads: In Part A (SAD) of the study, CRM will be used as supporting evidence for 
continuous assessment of MTD for dose escalation decisions.  No formal interim analysis will be 
performed in Part B (MAD) of the study. In Part B (MAD) of the study, in addition to the 
safety review (blinded), a designated team of staff will review the available unblinded but 
de-identified PD and/or biomarker data (eg., levels of SOD-1 and p-NFH) from all previous 
cohorts at the completion of the last Day 106 visit of each cohort to determine whether to 
proceed with the subsequent planned dose cohorts.  An interim analysis of key safety, 
secondary and exploratory endpoints may be conducted based on data up to the 60-mg 
and/or 100-mg dose cohort to allow for the planning of the pivotal efficacy and safety study. 
The subjects, investigative staff, and sponsor’s staff responsible for site monitoring and 
data management will remain blinded to treatment assignment during the ongoing data 
review, as well as during interim analyses, to minimize the potential for bias in the data 
cleaning process. Details of the interim analysis will be provided in a separate statistical 
analysis plan.


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Rationale: The implementation of an interim analysis during Part B of the study would allow for 
the timely determination of a possible effect on key biomarkers, thereby facilitating an earlier 
transition to pivotal studies without compromising overall study design.
This change also affects Section 7.2.1.2, Multiple Ascending Dose.


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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL
The major changes to the protocol are presented chronologically.  New text is shown in bold
type; deleted text is shown with a strikethrough.
Section 3, Synopsis
The Synopsis was revised to reflect changes made throughout the protocol.
Section 5.2, Current Therapies for Amyotrophic Lateral Sclerosis
Change: Included information on edaravone.
Now reads:
The only currently approved treatments for ALS are is Rilutek® (riluzole (Rilutek®), which is 
marketed globally, and edaravone (Radicava™), which is approved in the United States, 
Japan, and South Korea.  Riluzole provides a modest increase in survival (2 to 3 months) 
without noticeable improvement in strength or disability [Miller 2012]. Edaravone lessens 
functional decline as measured by the Amyotrophic Lateral Sclerosis Functional Rating 
Scale - Revised (ALSFRS-R). The effect of edaravone on survival is unknown [Writing 
Group and Edaravone (MCI-186) ALS 19 Study Group 2017]. No specific SOD1 ALS 
treatments are available.
Rationale: Edaravone was recently approved as a treatment for ALS; this change updates the 
information on current therapies for ALS.
Section 5.3.1.1, Toxicology
Change: Added description of a 9-month nonclinical toxicology study in cynomolgus monkeys
(NHPs).
Now reads:  
From the 9-month cynomolgus monkey toxicology study, the NOAEL for repeated, 
intrathecally-administered BIIB067 was 12 mg.  This was based on adverse clinical 
observations for 1 female administered 35 mg.  This female exhibited neurological signs 
after the second dose, characterized by transient muscle cramping (seen immediately after 
dosing on multiple days), prolonged recovery from anesthesia, and intermittent tremors 
(during the last months of the dosing phase).  Treatment with diazepam was required on 
several dosing occasions.  An electroencephalogram (EEG) on this animal revealed altered 
postdose signals (with effects on high frequency bands) but confirmed that muscle 
cramping during EEG recording was not a seizure and could have been related to arousal.  
This finding was considered test-article related; however, there were no correlates in 
clinical and anatomic pathology.  
Rationale: A long-term nonclinical toxicology study was recently completed to support clinical 
development of BIIB067, and the data generated in NHPs were used to update the dose rationale 
in this first-in-human study of BIIB067.
This change also affects Section 5.3.1, Nonclinical Experience.


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Section 5.5, Rationale for Dosing Regimen
Change: Updated the rationale for dosing regimen to include the 100-mg dose of BIIB067.
Now reads:
BIIB067 will be administered via intrathecal bolus at single ascending doses (SAD) to cohorts in 
Part A, and at multiple ascending doses (MAD) to cohorts in Part B.
The BIIB067 dosing regimens for this study were selected based on nonclinical toxicology and 
PK observations in nonhuman primate (NHP) studies using repeated-dosing intrathecal 
administration for 13 weeks and 9 months, and target tissue concentrations from SOD1 
transgenic mouse models. 
Based on pharmacology and PK results in SOD1 transgenic mice, the estimated tissue 
concentrations of BIIB067 needed to produce a 50%, and the upper 95% confidence interval of 
an 80%, SOD1 mRNA reduction within the human spinal cord are 0.9 µg/g and 4.7 µg/g, 
respectively.  Evaluations of cortex from the same experiment indicate that the estimated 
tissue concentration of BIIB067 needed to produce a 50% cortical SOD1 mRNA reduction 
is 8 µg/g.
The lowest dose selected for this study (10 mg) is predicted to achieve greater than 0.9 µg/g 
tissue concentration in the spinal cord. and cortex, while tThe initial highest proposed dose (60 
mg, multiple dose) iswas predicted to achieve greater than 4.7 µg/g steady-state tissue 
concentration in the spinal cord, and approximately 1.5 µg/g steady-state tissue concentration 
in the cortex, which is expected to yield approximately 15% to 20% SOD1 mRNA reduction 
in that tissue.  These tissue concentrations are predicted to span the pharmacologically active 
range. The addition of a 100-mg cohort is predicted to achieve steady-state exposures in the 
cortex of approximately 2.5 µg/g, which is predicted to be sufficient for a meaningful CSF 
SOD1 reduction of 25% to 30%. This reduction is expected to be clinically meaningful, 
based on the expectation that the reduction of SOD1 in tissues (spinal cord and cortex) 
would be greater than the 20% to 30% reduction observed in CSF.  This prediction is 
based on observations in NHP studies, where approximately 50% reduction in CSF 
corresponded to approximately 50% or greater reduction in the spinal cord and cortex.  In 
rodent efficacy experiments, doses of BIIB067 that reduced tissue SOD1 by approximately 
30% or more were found to improve measures of electrophysiology, function, and 
neurofilament.
Based on nonclinical PK and pharmacology data, and taking into consideration subject safety, 
the inconvenience of repeated intrathecal injections, and the rapid, fatal nature of ALS, the 
following dose intervals were selected for Part B of the study (MAD):  3 loading doses, once
every 2 weeks, and 2 maintenance doses, administered once every 4 weeks.  These intervals were 
selected based on the estimated t½ of BIIB067 (~1 month) in the target CNS tissues (spinal cord 
and brain cortex), to achieve and maintain the target tissue concentration of BIIB067 at a steady 
state level and within the estimated pharmacologically active range, and to facilitate effective 
SOD1 protein reduction in the CSF within Part B of the study (MAD).  
From the 139-weekmonth NHP toxicology study, the NOAEL for repeated, intrathecally-
administered BIIB067 was 35 12 mg.  No clinical or histologic observations were deemed 


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adverse in this study.  This NOAEL was converted to a human equivalent dose (HED) based on 
the nonclinical species NHP to human CSF volume scaling (approximately 10-fold difference).  
CSF volume scaling conservatively estimates the needed scaling factor and has predicted HED 
with reasonable accuracy.  The HED for the 139-weekmonth, intrathecal NHP toxicology study 
was calculated to be 350 120 mg.  This provides a 3512-fold safety margin for the BIIB067 
starting dose (10 mg), and a 5.82-fold safety margin for the highest planned dose (60 60-mg
dose).  The safety margin for a 100-mg clinical dose (highest planned dose) would be 1.2-
fold.  Preliminary PK data (plasma area under the concentration-time curve [AUC] from 
time 0 to 24 hours) from the 20-mg MAD cohort indicate that the safety margin based on 
exposure is 2.2-fold relative to a 100-mg clinical dose.  The 1.2-fold safety margin based on 
CSF volume scaling from the NHP toxicology study was chosen over the 2.2-fold safety 
margin calculated from the plasma steady-state exposures since the former provides a 
more conservative estimate.
Therefore, all BIIB067 doses planned for 233AS101 are predicted to be pharmacologically 
active, while maintaining sufficient safety margins calculated from the 139-weekmonth
intrathecal NHP toxicology study.
Rationale: This change was made based on BIIB067 exposure predictions related to addition of 
the 100-mg dose and updated information on the 9-month NHP toxicology study. The human 
equivalent dose and the safety margin relative to the new highest planned dose of 100 mg
(Cohort 8) were also included.
Section 7.2.2.2, Multiple Ascending Dose
Change: Added details of within cohort staggering for Cohort 8.
Now reads: 
Within eachcohorts 5-7 in Part B, subjects will be randomized in blocks of 4 to receive BIIB067 
or placebo in a 3:1 (active treatment:placebo) ratio.  The 3 blocks of each cohort will be dosed 
sequentially, each followed by a 72-hour safety data review period, during which the Biogen 
Medical Director and SABR Physician will review blinded safety data with the PI.
Given that safety and tolerability of the 100-mg dose of BIIB067 were not explored in Part 
A (SAD), both a sentinel dosing strategy and a review of safety data for every subject after 
the first dose will be incorporated into Cohort 8. 
In Cohort 8, the first 2 subjects (1 subject receiving placebo and 1 subject receiving 
BIIB067) will be dosed as a sentinel group, followed by a 72-hour safety data review period, 
during which the Biogen Medical Director and SABR Physician will review blinded safety 
data with the PI.  For the remaining subjects in the cohort, no more than 2 subjects will be 
given the first dose of study treatment on the same day throughout the study. 
Cohort 8 follows the same loading dose/maintenance dose as the other MAD cohorts. While 
a 100-mg dose has not been administered in the SAD portion of the study, the safety data 
collected between week 2 and week 4 postdose (or even week 1 and week 4 postdose) did 
not yield any additional information when compared with safety data collected for the first 
2 weeks postdose. This justifies the absence of a 4-week safety observation period between 
doses 1 and 2.


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Additional to the 72-hour safety review period, for every subject in Cohort 8, a review of all 
available safety and tolerability data will be performed approximately 1 week after the first 
dose is administered.  This review will be performed by the Biogen Medical Director and 
SABR Physician with the PI.  The second dose cannot be given until this review is 
complete.
Rationale: These changes were made to ensure safety evaluation of a single dose of BIIB067 
100 mg before proceeding with multiple dosing, as this dose level was not evaluated in the single 
ascending dose portion of this study.
Section 7.3.3.2, Part B:  Multiple Ascending Dose
Change:  To include the option of home visits.
Now reads:  
Subjects will return to the study site for follow-up visits after each dose on Day 8 (after first 
dose), Day 22 (after second dose), Day 36 (after third dose), Day 64 (after fourth dose), Days 92 
and 106 (after fifth dose), and on the final study visit on Day 169.  On the days of CSF sampling 
(Day 106 and Day 169), subjects will remain under observation for approximately 1 hour after 
the procedure and will receive a safety follow-up telephone call approximately 24 hours after the 
procedure.  Subjects will also receive follow-up telephone calls on Day 50 (after third dose) and 
Day 78 (after fourth dose) to provide information on AEs, SAEs, and concomitant medications 
or procedures.  Subjects may, at the discretion of the Investigator, have the option of home 
visits for non-dosing visits that do not require CSF collection or strength and 
electrophysiological measures, which are visits on Days 8, 36, and 64.
Rationale:  The Sponsor has a contract with Global Care to provide home visits; however, this 
option has not been used as the language was missing from the protocol.
This change also affects Section 4.1, Study Schematic: Figure 2; and Section 4.2, Schedule of 
Activities: Table 2, footnote 3. 
Section 7.4.1, Dose Suspension
Change: Updated language related to managing a serious adverse event (SAE) or a clinically 
significant adverse event (AE).
Now reads:
If 1 subject experiences either an SAE or a clinically significant AE (as defined by the 
Investigator or the Sponsor), the Biogen Medical Director and SABR Physician will discuss 
the event with the Investigator and review the SAE form (if applicable). If the AE is 
assessed as unrelated to the study treatment by both the Investigator and the Sponsor (e.g.,
it is a known sign or symptom of ALS, or it is an effect of the LP procedure), dose 
suspension is not necessary. 
If the SAE or clinically significant AE (as determined by the Investigator or the Sponsor) is 
assessed as related to the study treatment by the Investigator or the Sponsor, all dosing will 
be suspended until the event has been fully evaluated, including for potential relatedness to study 
drug, by the Biogen Medical Director, SABR Physician, Biostatistician, Clinical Pharmacologist,
and, if required, any ad hoc members.  Depending on the nature, severity, suspected on- or off-


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target toxicity, outcome, and frequency of the event, a decision (documented with supporting 
rationale) will be made to proceed with one of the following:  
•
Request additional safety data 
•
Continue dosing remaining subjects within the cohort
•
Enroll additional subjects to the current cohort 
•
Proceed with the planned dose escalation in the next cohort
•
Enroll additional subjects to previous (lower-dose) cohort
•
Stop the study
Rationale: This update was included to prevent any unnecessary dose suspensions for events 
clearly not related to the study treatment.
Section 7.4.2, Dose Termination
Change:  Updated dose termination criteria in case of recurrent SAEs or AEs. Also updated the 
individuals evaluating safety, tolerability, and PK data.
Now reads:  
After evaluation of safety, tolerability, and PK data by the Biogen Medical Director, SABR 
Physician, Biostatistician, Clinical Pharmacologist, and, if required, any ad hoc members, further 
dosing at the current level and dose escalation will be terminated if any of the following is 
observed:
•
Two similar SAEs (unless clearly unrelated to BIIB067 upon medical review) are 
reported for 2 subjects on active study treatment within the same cohortCurrent dose is not 
deemed to be safe.
•
Three or more similar AEs (unless clearly unrelated to BIIB067 upon medical 
review) that are either not tolerable (as reported by the subjects) or deemed a medically 
unacceptable risk by the Biogen Medical Director, SABR Physician, and, if required, any 
ad hoc members.
•
Sponsor requests that dosing be terminated. 
Rationale:  This change was made to explain the situations that could trigger dose termination if 
the dose administered is not deemed safe for the subjects.
Section 8.2, Exclusion Criteria
Change: Updated hepatitis C- and B-related exclusion criteria.
Now reads:
2.
History of, or positive test result at Screening, for hepatitis C virus antibody.
2.3.
Current hepatitis B infection (defined as positive for hepatitis B surface antigen 
[HBsAg] and/or hepatitis B core antibody [HBcAb]).  Subjects with immunity to hepatitis 
B from previous natural infection (defined as negative HBsAg, positive hepatitis B surface 
antibody immunoglobulin G, and positive HBcAb) or vaccination (defined as positive anti-


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9
HBs) are eligible to participate in the studyor hepatitis B virus (defined as positive for both 
hepatitis B surface antigen and hepatitis B core antibody).
Rationale: This update is to clarify the timing for the hepatitis C antibody test and to provide a 
more detailed definition for hepatitis B exclusion criteria.
Change: Included the use of edaravone as a criterion for exclusion from the study.
Now reads:
8.
Current or recent use (within 30 hours prior to screening), or anticipated need of 
edaravone (Radicava).
Rationale: Edaravone was recently approved as a treatment for ALS in the United States, and 
although its possible effect on various exploratory ALS biomarkers such as neurofilament or 
SOD1 clinically has not been reported, nonclinical models showed that it reduced SOD1 levels 
in rodent spinal cord. The use of edaravone was included as a criterion for exclusion from the 
study to avoid the interference from any of its potential clinical effects.
Change:  Included the presence of implanted vascular devices as a criterion for exclusion from 
the study.
Now reads:
9.
Presence of any implanted vascular devices.
Rationale: This change was made to avoid associated risks, including infection.
Section 9.1, Screening and Enrollment
Change: To permit rescreening of subjects who met eligibility but were not dosed within the 28-
day screening window.
Now reads: 
Subjects (or their legally authorized representative [e.g., spouse], where applicable) must provide 
informed consent before any screening tests are performed (see Section 17.3).  When a subject 
signs the informed consent form (ICF), that subject is considered to be enrolled in the study.  
Participating study sites are required to document all screened candidates initially considered for 
inclusion in this study.  If a subject is excluded from the study, the reasons for exclusion will be 
documented in the subject’s source documents and on the screening log.
Eligible subjects who are not able to complete the Day 1 Visit within 28 days of their 
screening assessments (Screening Visit 2) may be rescreened.
Rationale: This change may help reduce the impact of an expired screening window on 
recruitment time and allow the team to include subjects who would otherwise be eligible for the 
study but for the screening window expiration.
14.1, Clinical Safety Assessments
Change: Included a list of the type of neurological examinations to be conducted at the sites.
Now reads: 


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•
Limited Nneurological examinations (to be assessed by a trained specialist) of cranial 
nerves, coordination/cerebellar function, reflexes, motor, and MMSE (Mini-Mental State 
Examination – a 30-point questionnaire that is used to measure cognitive impairment; in
Part B only).  In Part B of the study, the neurological examination will include the Mini Mental 
State Examination (MMSE) a 30 point questionnaire that is used to measure cognitive 
impairment
Rationale: This change will eliminate confusion and enable consistency in the type of 
neurological examinations performed across all sites conducting the study.
This change also affects Sections 4.2, Schedule of Activities: Table 2; and 16.5.2.6, Limited 
Neurological Examinations.
14.2, Laboratory Safety Assessments
Change: To separate coagulation from other hematology assessments and to exclude total cell 
count from CSF analysis.
Now reads:
•
Hematology:  complete blood count with differential, platelet count, and absolute 
neutrophil count.  INR, PT, and APTT will also be measured
•
Coagulation: INR, PT, and APTT
•
Blood chemistry:  electrolytes, total protein, albumin, creatinine, blood urea nitrogen, uric 
acid, bilirubin (total and direct), alkaline phosphatase, alanine aminotransferase, aspartate 
aminotransferase, gamma glutamyl transferase, glucose, calcium, phosphorus, bicarbonate, 
chloride, sodium, and potassium
•
Urinalysis:  dipstick for blood, protein, and glucose (microscopic examination, if 
abnormal) 
•
Urine pregnancy tests
•
CSF analysis:  total cell count, red blood cell count, white blood cell count, protein, and 
glucose
Rationale: These changes were made for clarity, as coagulation is not part of the standard 
hematology assessments and the total cell count is not required for standard CSF analysis.
This change also affects Sections 4.2, Schedule of Activities, Table 2; and 16.5.2.2, Clinical 
Laboratory Results.
17.3, Subject Information and Consent
Change: Included update that subjects will be informed about the collection of sensitive data 
(race and ethnicity).
Now reads:  
Subjects will be informed, where applicable, that their race and ethnicity will be collected 
during the study (unless the collection is not permitted by applicable law or not approved 


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by the governing ethics committee) and the data will be used during analysis of study 
results.
Rationale:  This update was made to keep subjects informed about the collection of sensitive 
data 


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SUMMARY OF MINOR CHANGES TO THE PROTOCOL
The following minor changes were made to the protocol, as appropriate:

The version number and date were updated throughout the protocol.

Sponsor address in the United States was updated.

The List of Abbreviations was updated.

Section 4.1, Study Schematic, Figures 1 and 2 were replaced to correct minor errors.

Section 9.3, Blinding Procedures, was updated for consistency in the description of 
safety review blinding.

Use of abbreviation only (vs. spelled-out term) was fixed in Section 13.2, 
Pharmacokinetic Assessments.

A new reference was added to the list.


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Biogen MA Inc. 
1 
 
 
 
 
 
 
 
 
 
 
Biogen MA Inc. 
250 Binney Street 
Cambridge, MA  02142 
United States 
 
Biogen Idec Research Limited 
Innovation House 
70 Norden Road 
Maidenhead Berkshire 
SL6 4AY 
United Kingdom 
 
 
______________________________________________________________________ 
AMENDMENT SUMMARY 
Biogen Protocol 233AS101 
A Phase 1, Placebo-Controlled, Single and Multiple Ascending Dose Study to Evaluate the 
Safety, Tolerability, and Pharmacokinetics of BIIB067 Administered to Adult Subjects with 
Amyotrophic Lateral Sclerosis 
Version 3 
Date:  17 November 2016 
EUDRA CT 2015‐004098‐33 
Version 3 of the protocol has been prepared for this amendment, which supersedes Version 2. 
 


Protocol 233AS101, Version 3 
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2 
PRIMARY REASON FOR AMENDMENT 
The primary reason for this amendment to Protocol 233AS101 is to correctly reflect in Figure 2 
of the protocol that sampling for anti-BIIB067 antibody (Ab) will occur during nondosing 
clinical visits (except for predose on Day 1).  
New text is shown in bold type; deleted text is shown with a strikethrough. 
Section 4.1, Study Schematic (Figure 2: Study Design: Part B − Multiple Ascending Dose) 
Now reads: 
 




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Rationale:   
The schematic for Part B incorrectly lists collection of anti-BIIB067 Ab samples under dosing 
visits for doses 2 through 5. The sampling for anti-BIIB067 Ab should occur at all clinical 
follow-up visits, but not on the day of dosing per the Schedule of Events table.  Currently, 
Figure 2 indicates that sampling for anti-BIIB067 Ab occurs at the Follow-up Safety Visits and 
Dosing Visits.  
 
 


Protocol 233AS101, Version 3 
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5 
SUMMARY OF MAJOR CHANGES TO THE PROTOCOL 
Changes to the protocol are presented chronologically.  New text is shown in bold type; deleted 
text is shown with a strikethrough. 
Section 4.2, Schedule of Activities (Table 2: Schedule of Activities: Part B − Multiple Ascending 
Dose) 
Change:  Table 2 Schedule of Activities:  Part B – Multiple Ascending Dose was updated to add 
the collection of height at Visit 2. 
Now reads: 


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Table 2: 
Schedule of Activities:  Part B – Multiple Ascending Dose 
Tests and Assessments 
Screening 
Dosing Inpatient Period 
Dosing 
Days 15, 
29, 57 & 
85 
(±3 days) 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 
to Day -1 
Day 1 
Day 2 
24 (±1) 
Postdose 
Days 8, 22, 
36, 64, 92, 
and 106 
(±3 days) 
Days 50 & 
78  
(±3 days) 
via 
Telephone 
 
Day 169 
(±3 days) /Early 
Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Physical Examination 
 
X 
X 
 
X5 
X5 
X5 
 
X5 
Weight 
 
X 
X 
 
 
 
 
 
X 
Height 
 
X 
 
 
 
 
 
 
 


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Rationale:   
Height was being collected in Part A – Single Ascending Dose phase of the study and was not 
being collected in Part B – Multiple Ascending Dose phase.  Collection of height was added to 
Part B to align both components of the study. 
 
 
 


Protocol 233AS101, Version 3 
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SUMMARY OF MINOR CHANGES TO THE PROTOCOL 
The following minor changes were made to the protocol, as appropriate: 
• The version number and date were updated throughout the protocol. 
• Minor editorial changes were made as appropriate (e.g., addition of abbreviations to 
figure and table footnotes).  
• The sponsor signature page was updated. 
• Section 4.1 Study Schematic, Figure 1 Study Design: Part A – Single Ascending 
Dose was updated to reflect the sampling of peripheral blood mononuclear cell at the 
dosing visit and the sampling of biomarkers only at Day 29 to align with Table 1. 
 


CONFIDENTIAL 
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc. 
1 
 
 
 
 
 
 
 
 
 
 
Biogen MA Inc. 
250 Binney Street 
Cambridge, MA  02142 
United States 
 
Biogen Idec Research Limited 
Innovation House 
70 Norden Road 
Maidenhead Berkshire 
SL6 4AY 
United Kingdom 
 
 
______________________________________________________________________ 
AMENDMENT SUMMARY 
Biogen Protocol 233AS101 
A Phase 1, Placebo-Controlled, Single and Multiple Ascending Dose Study to Evaluate the 
Safety, Tolerability, and Pharmacokinetics of BIIB067 Administered to Adult Subjects with 
Amyotrophic Lateral Sclerosis 
Global Amendment Version 2 
Date:  10 October 2016 
EUDRA CT Number: 2015‐004098‐33  
Version 2 of the protocol has been prepared for this amendment, which supersedes Version 1. 
 


Protocol 233AS101, Version 2 
 
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PRIMARY REASON FOR AMENDMENT 
The primary reasons for this amendment to Protocol 233AS101 are 1) to add the review of 
pharmacokinetic (PK) data and clarify the review of safety data prior to each dose escalation in 
Part B (multiple-ascending-dose [MAD]) of the study and 2) to add the Mini-Mental State 
Examination (MMSE) as part of the neurological examination. 
New text is shown in bold type; deleted text is shown with a strikethrough. 
Section 7.2.1.2, Multiple Ascending Dose 
Now reads: 
After the last subject a minimum of 10 subjects within a cohort completes the Day 106 
Follow-Up Visit (~3 weeks after last dose), and prior to dosing of the next, higher dose cohort, a 
Biogen Medical Director and a SABR Physician will review the all available blinded safety data 
with the PI.  Review of blinded safety data may be followed by review of unblinded safety data 
of the current cohort and all available safety data from preceding cohorts by the Biogen Medical 
Director, SABR Physician, Biostatistician, Clinical Pharmacologist, and, if required, any ad hoc 
members.  In addition to review of the safety data, a Biogen Medical Director, Clinical 
Pharmacologist, and, if required, any ad hoc members will review PK data through the 
trough levels after the fourth dose (samples collected predose on Day 85) for a minimum of 
6 subjects within a cohort, prior to dosing of the next, higher dose cohort.  Before escalating 
to the next, higher dose level, there must be agreement that the current emerging safety, and 
tolerability, and PK data support dose escalation. 
Rationale:  To confirm that PK data will be obtained and analyzed before transitioning to the 
subsequent cohort for safety reasons and to ensure the assessment of PK at a steady state.   
This change also affects Figure 3: Dose Escalation Schematic. 
Section 14.1, Clinical Safety Assessments 
Now reads: 
The following clinical assessments will be performed to evaluate the safety profile of BIIB067: 
 Medical history 
 Physical examinations 
 Neurological examinations (to be assessed by a trained specialist).  In Part B of the 
study, the neurological examination will include the Mini-Mental State 
Examination (MMSE) – a 30-point questionnaire that is used to measure 
cognitive impairment 
Rationale:  The MMSE was added to assess possible changes in the subject’s cognitive 
performance. 
This change also affects Section 4.2, Schedule of Activities (Table 2: Part B – Multiple 
Ascending Dose). 
 


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SUMMARY OF MAJOR CHANGES TO THE PROTOCOL 
Changes to the protocol are presented chronologically.  New text is shown in bold type; deleted 
text is shown with a strikethrough. 
Section 3, Synopsis  
The Synopsis was revised to reflect changes made throughout the protocol. 
Section 6.3, Exploratory Objectives and Endpoints 
Change:  Questionnaires were added to the list of exploratory endpoints. 
Now reads: 
To evaluate the effect of BIIB067 on measures of clinical function. 
 The endpoints that relate to this objective are changes from baseline in the following 
measures:  
 ALS Functional Rating Scale - Revised (ALSFRS-R)  
 sSlow vital capacity (SVC). 
 
 
 
 
 
 
 
 
 
 
Rationale:  The questionnaires will enable assessment of any changes in subjects’ quality of life, 
which is an important component of clinical function. 
This change also affects Section 4.1, Study Schematic (Figure 2: Study Design: Part B – 
Multiple Ascending Dose); Section 4.2, Schedule of Activities (Table 2: Part B – Multiple 
Ascending Dose); Section 13.1, Exploratory Assessments of the Effect of BIIB067 on Clinical 
Function; and Section 16.1.2, Methods of Analysis. 
Section 7.1.1, Part A: Single-Ascending-Dose Evaluation: 
Change:  Eligibility criterion for Part A (single-ascending dose [SAD]) of the study was 
changed to allow only those patients with amyotrophic lateral sclerosis (ALS) caused by 
superoxide dismutase 1 (SOD1) mutation to enter the study. 
Now reads: 
Part A will be a randomized, double-blind, placebo-controlled, SAD study of up to 4 dose levels 
of BIIB067 administered to subjects with sporadic ALS or SOD1-ALS.  The dose levels will be 
evaluated sequentially.  Final sample size for Part A of the study will be determined by the 
incidence of DLT.  If no DLTs are encountered, a minimum of 20 subjects will be enrolled.  The 


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maximum sample size for Part A is 36 subjects.  Every attempt will be made to enroll subjects 
with SOD1 ALS into each dose cohort.  The first 3 dose levels will be assessed in cohorts of 
4 subjects each:  1 subject will be administered placebo, and 3 subjects will be administered 
BIIB067 at 10, 20, or 40 mg.   
Rationale:  This change was made to exclude subjects with sporadic ALS as these subjects were 
not expected to benefit from the treatment with the study drug.   
This change also affects Section 8.1, Inclusion Criteria 3. 
Section 7.3.1.1, Part A: Single-Ascending Dose 
Change:  The duration of Part A screening period was increased 
 
 
Now reads: 
For subjects who do not have documentation of a SOD1 mutation, the screening period will 
involve an additional visit (Screening Visit 1), where a blood sample will be collected for 
deoxyribonucleic acid (DNA) analysis.  The rationale for the extra screening visit is to 
ensure DNA analysis results prior to assessing the rest of the eligibility criteria.  Subject 
eligibility for the study will be determined during Screening Visit 2, up to approximately 
21 days after Screening Visit 1 and within 28 days prior to admission to the inpatient facility 
for dosing (Day 1).  Subjects in the 2 lowest dose cohorts, who choose to re-enroll into 1 of the 2 
highest dose cohorts, will have to repeat screening assessments before receiving the second dose.  
The This second additional Screening Visit can occur during the washout period, within 28 days 
prior to their second admission to the inpatient facility for dosing.  
 
. 
The Screening Visit 2 assessments may be performed over 2 days, which do not need to be 
consecutive, to minimize subject burden.  All assessments must be completed before Day 1. 
Rationale:  The duration of the study for Part A was increased 
 
. 
 
 
 
 
Section 9.2, Randomization and Registration of Subjects 
Change:  The number of replacement subjects that could be enrolled per cohort in Part B of the 
study was specified. 
Now reads: 
Up to 6 replacement subjects may be enrolled in Part B of the study (2 per cohort).  These 
additional subjects will be assigned to receive the same study treatment as the withdrawn 
subjects they will replace. 
Rationale:  This update was made to suggest that if subject(s) withdrew in Part B 
(multiple-ascending dose), and if the Sponsor decided to replace the subjects, then 2 subjects per 


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cohort (i.e., up to 14 subjects in each cohort) could be enrolled and would each receive the same 
treatment as the subject being replaced. 
 
Change:  
 
 
 
Now reads: 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
  
 
 
 
 
 
 
 


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Rationale:  
 
 
  
Section 15.5, Contraception Requirements 
Change:  Barrier method was removed from the list of highly effective contraception. 
Now reads: 
For the purposes of the study, highly effective contraception is defined as use of the following: 
For females: 
 Established use of oral, injected, or implanted hormonal methods of contraception. 
 Placement of an intrauterine device or intrauterine system. 
 Barrier methods of contraception with use of a spermicide: condom or occlusive cap 
(diaphragm or cervical/vault caps) with spermicidal foam/gel/cream suppository. The 
use of barrier contraceptives should always be supplemented with the use of a 
spermicide. 
 Male surgical sterilization (with the appropriate postvasectomy documentation of the 
absence of sperm in the ejaculate).  (For female subjects participating in the study, 
male sexual partners must have undergone surgical sterilization.) 
For males: 
 Effective male contraception includes aA vasectomy with negative semen analysis at 
follow up, or the use of condoms with spermicide. 
Rationale:  It was decided that barrier method will not be considered as highly effective 
contraception to be compliant with requirements of European Regulatory Agencies.  


Protocol 233AS101, Version 2 
 
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Biogen MA Inc. 
7 
SUMMARY OF MINOR CHANGES TO THE PROTOCOL 
The following minor changes were made to the protocol, as appropriate: 
 The version number and date were updated throughout the protocol. 
 A sponsor signature page was added to the protocol. 
 Section 2, List of Abbreviations, was updated to reflect changes in the protocol.  This 
change also affects Section 17, Ethical Requirements, for the definition of 
International Council for Harmonisation.Section 4.2, Schedule of Activities (Table 2: 
Part B – Multiple Ascending Dose), footnotes were updated to indicate that the 
ALSFRS-R assessment 
 
 HHD will be performed on Day 22 and Day 92.  A 
footnote was added to indicate that blood sampling for biomarkers will be collected 
on Day 106.  The table was also updated to move the FSH assessment from Screening 
V1 to Screening V2. 
 Section 5.3.2, Clinical Experience, the name of the company was updated from ISIS 
Pharmaceuticals to Ionis Pharmaceuticals to reflect the company’s recent name 
change. 
 Section 8.1, Inclusion Criterion 7, was updated to indicate that screening coagulation 
values should be within normal ranges.  It was clarified that subjects with 
nonclinically significant and stable out-of-range values may be eligible to enroll in 
the study at the discretion of the Investigator and after a consultation with the 
Sponsor.  This change also affects Section 4.2, Schedule of Activities, Table 1 and 
Table 2, Footnote 4. 
 Section 8.2, Exclusion Criterion 3, was updated to clarify that subjects receiving 
treatment with another investigational drug, including investigational drugs for ALS 
through compassionate use programs, will not be eligible to participate in the study. 
 Section 11.3.1.2, Disallowed Concomitant Therapy, was updated to remove 
memantine and coenzyme Q that were included in the protocol as examples of 
off-label medications for ALS treatment to avoid any confusion resulting from citing 
an incomplete list of medications. 
 Section 13, Efficacy, Pharmacokinetic, and Pharmacodynamic Assessments, was 
updated to change all instances of the use of the term “efficacy” in the protocol to 
“clinical function” and to emphasize that the clinical function measurements will only 
be exploratory in nature.  This change also affects Section 16.1.1, Analysis 
Population, wherein the “efficacy set” is termed “clinical function set.” 
 Section 14.2, Laboratory Safety Assessments, was updated to clarify that 
cerebrospinal fluid (CSF) analysis will also include red blood cell count and white 
blood cell count.  Updates were made to clarify that platelet and coagulation tests will 
be collected at every visit (including screening) and analyzed centrally as safety 
laboratory tests for the study. 


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 Section 15.3.2, Serious Adverse Events, was updated to clarify that the ICF 
mentioned in this section refers to the first (main) ICF. 
 Section 19.1.4, Laboratory Assessments, was updated to clarify that urine pregnancy 
tests will be collected and analyzed in the clinic; however, CSF samples will be 
collected in the clinic and analyzed at the local laboratory.  In addition, it was 
clarified that repeat coagulation or hematology tests, if required, will be collected in 
the clinic and sent to the local laboratory for analysis.  The section header was 
updated to reflect this change. 
 Section 19.2, Publications, was moved to Section 18.5 to adhere to template 
guidance. 
 Section 20, References, was updated to reflect changes in the protocol.  Reference to 
the article by Brooks et al was removed because the reference to sporadic ALS has 
been removed from Inclusion Criteria 3. 

SAP_001.pdf: 
Statistical Analysis Plan – Part A (SAD) and Part B (MAD)
Final Version No.:  1.0 
 Study Title: A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation 
Name of Study Treatment: BIIB067 
Protocol No.: 233AS101/ NCT02623699 
Study Phase: 1/2/3 
Confidential Information 
The information contained in this Statistical Analysis Plan (SAP) is confidential and may not 
be reproduced or otherwise disseminated without the approval of Biogen, Inc.   




 
 
 
TABLE OF CONTENTS 
 
1. 
Introduction ............................................................................................................................. 8 
1.1 
Primary objective and endpoints ................................................................................. 8 
1.2 
Secondary objectives and endpoints ............................................................................ 9 
1.3 
Exploratory objective and endpoints ........................................................................... 9 
2. 
PART A: Single-Ascending-Dose (SAD) Evaluation .......................................................... 10 
2.1 
Study Design .............................................................................................................. 10 
2.2 
Statistical Methods: General Considerations ............................................................. 16 
 Analysis Populations ................................................................................................. 16 
 Data from Early Withdrawal or Unscheduled Visits ................................................ 17 
2.3 
Study Subjects ........................................................................................................... 17 
 Subject Accountability .............................................................................................. 17 
 Demography and Baseline Disease Characteristics .................................................. 17 
 Extent of Exposure .................................................................................................... 18 
 Concomitant Medications and Non-Drug Treatments/Procedures ........................... 19 
 Protocol Deviations ................................................................................................... 19 
2.4 
Safety Data ................................................................................................................. 20 
 Adverse Events .......................................................................................................... 20 
 Laboratory Data......................................................................................................... 21 
 Vital Signs ................................................................................................................. 22 
 ECG ........................................................................................................................... 23 
 Limited neurological examinations ........................................................................... 23 
 Columbia Suicide Severity Rating Scale (C-SSRS) ................................................. 24 
2.5 
Pharmacokinetic Data ................................................................................................ 24 
2.6 
Pharmacodynamic Data ............................................................................................. 25 
2.7 
Immunogenicity Data ................................................................................................ 25 


 
 
 
2.8 
Clinical Function Data ............................................................................................... 26 
3. 
Part B: Multiple-Ascending-Dose (MAD) Evaluation ......................................................... 28 
3.1 
Study Design .............................................................................................................. 28 
3.2 
Statistical Methods: General Considerations ............................................................. 36 
 Analysis Populations ................................................................................................. 36 
 Data from Early Withdrawal or Unscheduled Visits ................................................ 37 
3.3 
Study Subjects ........................................................................................................... 37 
 Subject Accountability .............................................................................................. 37 
 Demography and Baseline Disease Characteristics .................................................. 38 
 Extent of Exposure .................................................................................................... 39 
 Concomitant Medications and Non-Drug Treatments/Procedures ........................... 39 
 Protocol Deviations ................................................................................................... 40 
3.4 
Safety Data ................................................................................................................. 40 
 Adverse Events .......................................................................................................... 40 
 Laboratory Data......................................................................................................... 41 
 Vital Signs ................................................................................................................. 43 
 ECG ........................................................................................................................... 43 
 Mini-Mental State Exam (MMSE) ............................................................................ 44 
 Limited neurological examinations ........................................................................... 44 
 Columbia Suicide Severity Rating Scale (C-SSRS) ................................................. 45 
3.5 
Pharmacokinetic Data ................................................................................................ 45 
3.6 
Pharmacodynamic Data ............................................................................................. 46 
3.7 
Immunogenicity Data ................................................................................................ 49 
3.8 
Clinical Function Data ............................................................................................... 50 
4. 
Sample Size Justification ...................................................................................................... 61 
5. 
Changes to Planned Analyses ............................................................................................... 61 
6. 
References ............................................................................................................................. 62 


 
 
 
Appendix A: Derivation of C-SSRS ............................................................................................. 63 
Appendix B: Derivation and Imputation of Clinical Function Endpoint ...................................... 65 
 74 
 
 
 


 
 
 
 
List of Abbreviations 
ADM 
abductor digit minimi 
AE 
adverse event 
ALS 
amyotrophic lateral sclerosis 
ALSFRS-R 
ALS Functional Rating Scale (revised) 
ALT 
alanine aminotransferase 
ANCOVA 
analysis of covariance 
APB 
abductor pollicis brevis 
aPTT 
Activated partial thromboplastin time 
AST 
aspartate aminotransferase 
BB 
bicep 
BLQ 
below limit quantitation 
bpm 
beats per minute 
BP 
bodily pain 
BUN 
Blood urea nitrogen 
 
CO2 
Bicarbonate 
CS 
compound symmetry 
CSF 
Cerebral-spinal fluid 
 
C-SSRS 
Columbia suicide severity rating scale 
DLT 
dose limiting toxicity 
ECG 
Electrocardiogram 
EDB 
extensor digitorum 
EOS 
end of study (visit) 
ET 
early termination (visit) 
FDIO 
First dorsal interosseous 
GGT 
gamma-glutamyl transferase 
HHD 
hand-held dynamometry 
INR 
International normalized ratio 
ITT 
intent-to-treat 
LLOQ 
lower limit of quantitation 
LOCF 
last observation carried over 
LS 
least square 
LP 
lumbar puncture 
MAD 
multiple ascending dose 
MedDRA 
Medical Dictionary for Regulatory Activities 


 
 
 
mg 
milligram 
mmHg 
millimeters of mercury 
MMRM 
Mixed Model for Repeated Measures 
MMSE 
mini-mental state exam 
N 
number of subjects or observations 
NFH 
neurofilament heavy chain 
NFL 
neurofilament light chain 
PCS 
Physical component score 
PD 
pharmacodynamics 
PK 
pharmacokinetic(s) 
p-NFH 
phosphorylated axonal neurofilament heavy chain 
PT 
prothrombin time 
QTc 
interval between the start of the QRS complex and the end of the 
T wave, corrected for heart rate 
QTcB 
QTc interval using Bazett’s formula 
QTcF 
QTc interval using Fridericia’s formula 
RBC 
red blood cell (count) 
TA 
tibialis anterior 
SAD 
Single ascending dose 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SD 
standard deviation 
SOC 
System organ class 
SOD 
superoxide dismutase 1 
SVC 
slow vital capacity 
ULN 
Upper limit of normal 
UN 
unstructured 
vs. 
versus 
WBC 
white blood cell (count) 
WHO 
World Health Organization 
 
 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
CONFIDENTIAL 
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc. 
8 
1. Introduction 
Study 233AS101 is a randomized, double-blind, placebo-controlled, 3-part study to examine the 
efficacy, safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of BIIB067, 
administered by intrathecal bolus injection to up to approximately 144 subjects with ALS and 
confirmed SOD1 mutation. 
Parts A and B are single and multiple dose escalating parts, respectively, in which subjects will 
be randomized to receive BIIB067 or placebo in a 3:1 (active:placebo) ratio.  In Part C, subjects 
will be randomized to receive BIIB067 100 mg or placebo in a 2:1 (active:placebo) ratio.  This 
statistical analysis plan is prepared for clinical study report of Parts A and B; a separate statistical 
analysis plan will be prepared for Part C.   
Part A will be a randomized, double-blind, placebo-controlled, single-ascending-dose (SAD) 
study of up to 4 dose levels (10, 20, 40 and 60 mg) of BIIB067 administered to up to 36 subjects 
with sporadic ALS or SOD1-ALS. Subjects within the 2 lower dose cohorts may re-enroll within 
the 2 higher dose cohorts, after a washout period.  Each cohort will be randomized to receive 
BIIB067 or placebo in a 3:1 (active:placebo) ratio.  
Part B will be a randomized, double-blind, placebo-controlled, multiple-ascending-dose (MAD) 
evaluation of up to 4 dose levels (20, 40, 60 and 100 mg) of BIIB067 administered up to 5 times 
to approximately 48 adults with SOD1-ALS. Each cohort will be randomized to receive BIIB067 
or placebo in a 3:1 (active:placebo) ratio.  
Unblinded interim analyses have previously been conducted on all subjects from all cohorts in 
Part A and Part B. At the time of the second interim analysis including all Part B cohorts, Cohort 
8 subjects were ongoing in the study so the interim analysis included partial data from this 
cohort. These interim analyses were pre-specified in separate statistical analysis plans (Interim 
Statistical Analysis Plans V2.0 and V3.0).  
1.1 
 Primary objective and endpoints 
The primary objective of Parts A and B of this study is to evaluate the safety, tolerability, and PK 
of BIIB067 in adults with ALS and confirmed SOD1 mutation. 
The primary endpoints are as follows: 
• Incidence of adverse events and serious adverse events (SAEs) 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
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• Incidence of abnormalities in clinical laboratory assessments, vital signs, physical 
and neurological examinations, and electrocardiograms (ECGs). 
• PK measures, including plasma and cerebrospinal fluid (CSF) levels of BIIB067. 
1.2 
Secondary objectives and endpoints 
The secondary objective is to evaluate the effects of BIIB067 on levels of SOD1 protein in the 
CSF. 
• The secondary endpoint is the change from baseline in CSF levels of SOD1 
protein. 
1.3 
Exploratory objective and endpoints 
To evaluate the effect of BIIB067 
 
 handheld dynamometry (HHD).  
• The endpoints that relate to this objective are the changes from baseline in 
 
 HHD scores.  
To evaluate the effect of BIIB067 on measures of clinical function. The endpoints that relate to 
this objective are changes from baseline in the following measures:  
• ALS Functional Rating Scale - Revised (ALSFRS-R) scores  
• Slow vital capacity (SVC)  
 
  
 
  
 
  
 
  
 
  
 
To explore possible relationships between 
 
 
phosphorylated axonal neurofilament heavy chain (p-NFH), and neurofilament light chain 
(NFL). 
• 
 
 
 
 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
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2. PART A: Single-Ascending-Dose (SAD) Evaluation 
2.1 
Study Design  
Part A will be a randomized, double-blind, placebo-controlled, SAD study of up to 4 dose levels 
of BIIB067 administered to subjects with sporadic ALS or SOD1-ALS. The protocol was later 
amended to only allow subjects with SOD1-ALS. The dose levels will be evaluated sequentially. 
Final sample size for Part A of the study will be determined by the incidence of dose limiting 
toxicity (DLT). If no DLTs are encountered, a minimum of 20 subjects will be randomized. The 
maximum sample size for Part A is 36 subjects. The first 3 dose levels will be assessed in 
cohorts of 4 subjects each: 1 subject will be administered placebo, and 3 subjects will be 
administered BIIB067 at 10, 20, or 40 mg. The last dose level will be assessed in a cohort of 8 
subjects: 2 subjects will be administered placebo, and 6 subjects will be administered BIIB067 at 
60 mg. Up to 16 additional subjects may be enrolled into the selected dose levels (4 administered 
placebo and 12 administered BIIB067), based on the incidence of DLT.  
If no DLTs are observed in the 2 lower dose cohorts, then subjects within these 2 lower dose 
cohorts may re-enroll, after a washout period of at least 5 times the t½ (~20-week; including the 
8-week follow-up period), within the 2 higher dose cohorts. These subjects will repeat the 
screening assessments prior to re-enrolling, and will be rerandomized into either the BIIB067 or 
placebo group. 
The duration of study participation for each subject enrolled in Part A will be up to 
approximately 15 weeks, which will include an up to 7-week screening period and an 8-week 
follow-up period. For subjects who choose to re-enroll in a higher dose cohort, the total duration 
will be approximately 35 weeks, which will include a washout period of 3 times the t½ (~12 
weeks) after the 8-week follow-up visit (total washout of 5 times the t½, or ~20 weeks). 
Subjects who re-enroll in a higher cohort will repeat Screening Visit 2 assessments, which can 
occur during the washout period. 
The SAD portion of the study will be completed when any one of the following criteria is met. 
• MTD or the highest planned dose has been given to up to 9 active subjects. 
• A maximum of 36 subjects have been enrolled. 
Figure 1 is the study schematic and Table 1 shows the schedule of assessments.




 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
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12 
Table 1: 
Schedule of Activities:  Part A – Single Ascending Dose 
Tests and Assessments 
Screening 
Dosing Inpatient Period 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 to 
Day -1 
Day 1 
Day 2 
24 (±1) 
hours 
Postdose 
Days 8 & 
29  
(±3 days) 
Day 57 (±3 days)/ 
Early Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Informed Consent (main) 
X 
X3 
 
 
 
 
 
Medical History 
 
X 
X 
 
 
 
 
Clinical Laboratory Samples to Verify 
Eligibility4 
 
X 
 
 
 
 
 
FVC 
 
X 
 
 
 
 
 
Admission to Inpatient Facility 
 
 
X 
 
 
 
 
Physical Examination 
 
X 
X 
 
X5 
X5 
X5 
Weight 
 
X 
X 
 
 
 
X 
Height 
 
X 
 
 
 
 
 
Neurological Examination 
 
X 
X 
X6 
X 
X 
X 
Vital Signs (temperature, blood pressure, 
pulse rate, respiratory rate) 
 
X 
X 
X7 
X 
X 
X 
12-Lead ECG8 
 
X 
X 
X7 
X 
X 
X 
C-SSRS Questionnaire 
 
 
X 
 
 
 
X9 
Urine Pregnancy Test10 
 
X 
X 
 
 
 
X 
FSH Test11 
 
X 
 
 
 
 
 


 
 
 
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BIIB067 in Adults with ALS 
 
 
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13 
Tests and Assessments 
Screening 
Dosing Inpatient Period 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 to 
Day -1 
Day 1 
Day 2 
24 (±1) 
hours 
Postdose 
Days 8 & 
29  
(±3 days) 
Day 57 (±3 days)/ 
Early Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Randomization 
 
 
X 
 
 
 
 
Study Drug Administration 
 
 
 
X 
 
 
 
SVC 
 
 
X 
 
 
X 
X 
ALSFRS-R 
 
X 
X 
 
 
X 
X 
HHD 
 
X 
 
 
 
X12 
X 
Clinical Laboratory Samples for 
Hematology, Chemistry, and Urinalysis 
 
X 
X 
 
X 
X 
X 
CSF Samples13 
 
 
X 
 
 
X14 
X 
Blood Samples for Plasma anti-BIIB067 Ab 
 
 
X 
 
 
X 
X 
Blood Samples for Biomarkers 
 
 
X 
 
 
X12 
X 
Blood Samples for Plasma PK 
 
 
X 
X16 
X 
X 
X 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
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14 
Tests and Assessments 
Screening 
Dosing Inpatient Period 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 to 
Day -1 
Day 1 
Day 2 
24 (±1) 
hours 
Postdose 
Days 8 & 
29  
(±3 days) 
Day 57 (±3 days)/ 
Early Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Discharge from Inpatient Facility 
 
 
 
 
X 
 
 
AE and Concomitant Therapy and 
Procedures Recording 
 
 
-------------------------------------------------X (ongoing) -------------------------------
-- 
SAE Recording 
-------------------------------------------------X (ongoing) ---------------------------------------------------------------- 
Ab = antibody; AE = adverse event; ALS = amyotrophic lateral sclerosis; ALSFRS-R = Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised; 
CSF = cerebrospinal fluid; C-SSRS = Columbia Suicide Severity Rating Scale; DNA = deoxyribonucleic acid; ECG = electrocardiogram, 
 
; FSH = follicle-stimulating hormone; FVC=forced vital capacity; HHD = handheld dynamometry; 
 
 PK = pharmacokinetic(s); 
; SAE = serious adverse event; SOD1 = superoxide dismutase 1; 
SVC = slow vital capacity; V = visit 
1 Required only for subjects without a prior documentation of SOD1 mutation.  Results must be available before performing Screening Visit 2 assessments. 
2 Screening assessments can be performed over ~2 days (need not be consecutive) to minimize subject burden. 
3  Not required if collected during Screening Visit 1. 
4 Including blood samples for human immunodeficiency virus, hepatitis C virus, and hepatitis B virus tests, and platelet and coagulation tests.  Coagulation tests 
may be repeated at the local laboratory once if, in the opinion of the Investigator, values of the initial tests are only slightly out of range.  Subjects with 
nonclinically significant and stable out-of-range values for coagulation tests may be eligible to enroll in the study at the discretion of the Investigator, and after 
a consultation with the Sponsor. 
5 Limited physical examination will be conducted at the Investigator's discretion. 
6 To be assessed at 3 and 6 hours postdose. 
7 To be assessed within an hour prior to drawing PK blood samples at 2 and 4 hours postdose. 
8 Triplicate 12-lead (paper) ECGs will be obtained after the subject has rested in a supine position for at least 10 minutes.  The first ECG will be interpreted, and 
the last 2 will be checked for consistency and quality. 
9 Use the “Since Last Visit” version of C-SSRS. 
10 For women of childbearing potential only. 
11 To confirm postmenopausal status in postmenopausal female subjects. 
12 Day 29 only. 
13 Lumbar puncture (LP) will be performed to collect CSF samples for PK, pharmacodynamic, safety, and biomarker analysis.  The results of the most recent (i.e., 
obtained at Screening or other visit during the study) coagulation tests and platelet count must be reviewed before each LP can be performed.  Should the 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
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results suggest, in the opinion of the Investigator, that an LP may be safely performed, then no further laboratory values need to be reviewed.  However, should, 
in the opinion of the Investigator, repeat coagulation and platelet tests be clinically indicated, then these tests may be done locally to facilitate timely review.  
Results of any repeat tests must be available before the LP can be performed. 
14 To be collected at Day 29 only.  Subjects will remain under observation in the clinic for approximately 1 hour after the LP procedure and will receive a safety 
follow-up telephone call ~24 hours after the procedure. 
 
 
 
16 To be collected at 1, 2, 4, and 6 hours postdose. 


 
 
 
Protocol 233AS101 
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Final Version 1.0 
 
16 
 
2.2 
Statistical Methods: General Considerations  
Descriptive summary statistics will be presented for all primary, secondary and exploratory 
endpoints collected. Unless otherwise specified, for continuous endpoints, the summary statistics 
will generally include: number of subjects with data, mean, standard deviation, median, first and 
third quartiles and range.  For categorical endpoints, the summary statistics will generally 
include:  number of subjects with data, and the percentage of those with data in each category.  
Placebo patients across cohorts 1 to 4 in Part A will be combined for Part A summaries. All 
summaries will be presented by dose group unless otherwise specified. Some summaries may 
also present the overall population combining both placebo and active dose groups. 
The statistical software, SAS® version 9.4 or above, will be used for all summaries and statistical 
analyses.  
As a general rule, any visit/dose group combination that only has data for 1 patient will not be 
presented in group plots. However, all data will be summarized, listed and included in spaghetti 
plots, unless otherwise specified. 
 Analysis Populations 
2.2.1.1 ITT Population 
The ITT (Intention-to-Treat) population is defined as all randomized subjects who receive at 
least 1 or a part of 1 dose of study treatment (BIIB067 or placebo) in Part A. In case of any 
subjects who are mis-randomized, the ITT analysis will be based on treatment assignment at the 
time of randomization.  
2.2.1.2 Safety Population 
The safety population is defined as the ITT population of subjects in Part A. This will be the 
primary population for the analysis of safety endpoints. In the case of any subjects who are mis-
randomized, the any analyses based on the safety population will be based on actual treatment 
received. If a population is not specified otherwise for an analysis of safety, the safety population 
should be used. 
2.2.1.3 Pharmacokinetic (PK) Population 
The PK population is defined as the subset of the ITT population of subjects with at least 1 post-
dose PK measurement in Part A. 


 
 
 
Protocol 233AS101 
Single and Multiple Dose Study of 
BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
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2.2.1.4 Pharmacodynamic (PD) Population 
The PD population is defined as the subset of the ITT population of subjects with at least 1 post-
dose PD measurement in Part A.  
2.2.1.5 Clinical Function Set 
The clinical function set is defined as the subset of the ITT population of subjects who have at 
least 1 post-dose clinical function measurement in Part A. Subjects will be analyzed in the dose 
group to which they are randomized. This will be the population for the analysis of clinical 
function endpoints.  
2.2.1.6 Immunogenicity Population 
The analysis population for immunogenicity is defined as all subjects in the safety population 
who have at least 1 post-dose sample evaluated for immunogenicity in Part A.  
 Data from Early Withdrawal or Unscheduled Visits 
For subjects who are early terminated (ET), EOS visit is defined as the scheduled follow-up visit 
after ET visit.  
Any assessments of clinical functions at unscheduled visits will not be used in the analysis but 
will be listed.  
2.3 
Study Subjects 
 Subject Accountability  
The number (and percentage) of subjects randomized; dosed; completed the treatment; 
completed the study; discontinued treatment and the reasons for discontinuation; and withdrew 
from study early and the reasons for withdrawal will be summarized in a table.  
A listing of subjects who discontinued treatment/withdrew from study and the associated reasons 
for discontinuation/withdrawal will be presented.  
The number (and percentage) of subjects randomized by country and site, the number (and 
percentage) of subjects who completed the study by country and site, and number (and 
percentage) of subjects by analysis population will be summarized by dose group and for all 
subjects. 
 Demography and Baseline Disease Characteristics 
All demographics and ALS disease history data will be summarized for the ITT population. 


 
 
 
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Final Version 1.0 
 
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Demographic data, including age (years), age category (18-<35,35-<50, 50-<65, ≥65), gender, 
ethnicity, race, height, weight and body mass index (BMI) will be summarized by dose group 
and for all subjects.  BMI will be calculated as weight (kg) / height2 (m2).  
ALS disease history will also be summarized by dose group and for all subjects using descriptive 
statistics.  These include form of ALS, mutant genes among familial ALS, SOD1 mutation 
subtype (variant), time since ALS symptom onset, site of onset, time since ALS diagnosis, pre-
randomization ALSFRS-R slope and riluzole usage/duration. Additionally, a listing of individual 
subjects with known SOD1 mutation types will be provided. 
Time since ALS symptom onset will be calculated in months as (date of first dose received – 
date of ALS symptom onset)/30.4375. Time since ALS diagnosis will be calculated in months as 
(date of first dose received – date of ALS diagnosis)/30.4375. For the purpose of these 
calculations, partial dates for ALS symptom onset or ALS diagnosis will be imputed as follows: 
missing day will be imputed with 15th and missing month/day will be imputed with January 
15th.  
The pre-randomization ALSFRS-R slope will be calculated using the ALSFRS-R score at 
baseline (Day 1) i.e. Baseline ALSFRS-R score – maximum possible score of 48/duration of 
symptom onset, where duration of symptom onset will be calculated as (date of baseline 
ALSFRS-R score – date of symptom onset)/30.4375. Partial dates for symptom onset will be 
handled as defined above.  
Medical history will be classified using MedDRA version 22.0.  A summary of medical history 
by system organ class and preferred term will also be provided. 
 Extent of Exposure 
Since all subjects are planned to receive a single dose of placebo or BIIB067, no additional 
summary of extent of exposure will be provided. Separate listings will be provided showing what 
subjects were randomized to as well as study drug administration which will include lot 
numbers. 
Time on study will be summarized descriptively by dose group. Time on study will be calculated 
as (end of study date – first dose date + 1).  
 
 


 
 
 
Protocol 233AS101 
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BIIB067 in Adults with ALS 
 
 
Final Version 1.0 
 
19 
 
 Concomitant Medications and Non-Drug Treatments/Procedures 
Concomitant medications will be coded using the World Health Organization (WHO) dictionary 
WHODRUG (March 2019) and concomitant non-drug treatments/procedures using the Medical 
Dictionary for Regulatory Activities (MedDRA) version 22.0. 
Medications and non-drug treatments are considered concomitant if they are taken during the 
study. This includes medications/treatment/procedures that were started prior to the date and 
time of first dose of study drug if their use continued on or after the date and time of first dosing. 
If the start date is available but start time is missing and the medication/non-drug treatment start 
date is the same as the first dose date, the medication/non-drug treatment will be considered 
concomitant. Similarly, if the stop date is available but stop time is missing and the 
medication/non-drug treatment stop date is the same as the first dose date, the medication/non-
drug treatment will also be considered concomitant. Medications/therapies with missing start or 
stop dates and times, will also be considered as concomitant in the following situations: 
• If both the start and stop dates and times of a medication/treatment/procedure are 
missing; 
• If the start date and time of a medication/treatment/procedure is missing and the stop date 
and time of the medication/therapy occurred on or after the date and time of first dose of 
study drug; 
• If the start date and time of a medication/treatment/procedure therapy occurred prior to 
the date and time of first dose of study drug and the stop date and time of the 
medication/treatment/procedure is missing and the medication/treatment/procedure is 
listed as ongoing; 
If the start date and time of a medication/treatment/procedure occurred prior to the date and time 
of first dose of study drug and the stop date and time of the medication/treatment/procedure is 
missing and the medication/therapy is not listed as ongoing, then the 
medication/treatment/procedure will not be considered as concomitant. 
The number and percentage of subjects taking any concomitant medications will be summarized 
by dose group for the safety population. The number and percentage of subjects taking any 
concomitant non-drug treatments will also be summarized by dose group for the safety 
population.  
 Protocol Deviations 
Protocol deviations identified during site monitoring will be captured in a protocol deviation log. 
All protocol deviations will be listed and a summary of major protocol deviations by dose group 
will be presented. 


 
 
 
Protocol 233AS101 
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2.4 
Safety Data  
The safety population will be used for the analyses of the safety data. Safety data will be 
summarized using descriptive statistics by dose group.  
 Adverse Events 
All AEs will be classified using MedDRA version 22.0.  All AEs will be listed but only 
treatment emergent AEs will be summarized, where treatment emergence will be relative to the 
first dose of study drug. A treatment emergent AE/SAE is defined as any AE/SAE with an onset 
date and time that is on or after the first dose of study drug or any pre-existing condition that has 
worsened in severity after the first dose of study drug.  In case of missing dates, any AE/SAE 
with both a missing onset date and resolution date, or any AE/SAE with a missing onset date and 
a resolution date which is after the first dose of study drug, will be considered treatment 
emergent. If the onset date is available but onset time is missing and the AE onset date is the 
same as the first dose date the AE will be considered treatment emergent. The incidence of 
treatment emergent AEs will be summarized by dose group as follows: 
• by MedDRA preferred term 
• by primary system organ class (SOC) and MedDRA preferred term 
• by maximum toxicity grade, primary SOC and MedDRA preferred term 
• AEs related to lumbar puncture by primary SOC and MedDRA preferred term 
 
For the AE summary by primary system organ class and preferred term, subjects will be counted 
only once within each primary SOC/MedDRA preferred term. For the summary of AEs by 
maximum toxicity grade, primary system organ class and preferred term, subjects will be 
counted only once within each primary SOC/MedDRA preferred term and will only be counted 
under the maximum toxicity grade.  
Listings of the following events will be produced.  If the number of events is large, the incidence 
of these events may also be summarized in tables: 
• AEs related to study drug 
• AEs led to discontinuation of study drug 
• AEs led to withdrawal from study 
• AEs leading to study drug interruption 
If a summary is provided for related AEs and if the relationship for an event is missing then this 
will be summarized as unknown. Listing of deaths will be provided if applicable. 


 
 
 
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SAEs will also be summarized by primary MedDRA preferred term.  
 Laboratory Data 
Laboratory data will be evaluated to determine the incidence of abnormalities that emerge during 
the course of the study.  Changes in laboratory evaluations will be presented relative to baseline, 
which is defined as the closest visit prior to the subject starting treatment. 
The following clinical laboratory parameters are assessed in the protocol: 
• Hematology panel: complete blood count with differential (hematocrit, hemoglobin, 
platelets, red blood cell count [RBC], white blood cell count [WBC], basophils, 
eosinophils, lymphocytes, monocytes, neutrophils) 
• Blood chemistry panel: albumin, total bilirubin, direct bilirubin, alkaline phosphatase, 
alanine aminotransferase (ALT) (SGPT), aspartate aminotransferase (AST) (SGOT), 
gamma-glutamyl transferase (GGT), sodium, potassium, calcium, chloride, phosphate, 
blood urea nitrogen (BUN), creatinine,  uric acid, bicarbonate (CO2), glucose, total 
protein. 
• Urinalysis:  blood, glucose, protein, and microscopic examination if abnormal 
• CSF analysis: RBC, WBC, protein, glucose. 
If multiple samples are collected at the same visit, the samples collected at the earliest date/time 
will be analyzed. For CSF laboratory parameters, tube 2 results will be analyzed if available.  
Baseline value is defined as data collected which are prior to and/or on the date of the first dose, 
usually also the same day as the Day 1 visit.  If there is more than one value on or before Day 1, 
then the last non-missing value prior to (including on) the date of first dose will be used as the 
baseline value.  
Each hematology, blood chemistry, and CSF laboratory parameter will be flagged as “low” or 
“high” relative to the parameter’s normal range or as “unknown” if no result is available.  For 
each urinalysis laboratory parameter, the number and percentage of subjects experiencing post-
dosing shifts to ‘high’ (positive) will be summarized. For each hematology, blood chemistry, and 
CSF parameter, the number and percentage of subjects experiencing post-dosing shifts to ‘low’ 
or ‘high’ will be summarized.  In each summary, the denominator for the percentage is the 
number of subjects at risk for the shift.  The number at risk for the shift to low is the number of 
subjects whose baseline value was not low and who had at least one post-baseline value.  The 
number at risk for the shift to high is the number of subjects whose baseline value was not high 
and who had at least one-post baseline value.   Subjects will be counted only once for each 
parameter and each shift regardless of how many post-dosing assessments had that type of shift.   


 
 
 
Protocol 233AS101 
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Final Version 1.0 
 
22 
 
Summary statistics for actual values and change from baseline in laboratory values will be 
summarized by dose group and visit.  Line plots for chemistry, hematology and CSF showing 
mean value for each dose group at each visit will also be presented. 
Listings of all chemistry, hematology, CSF, urinalysis values and urine pregnancy test will be 
provided.  Abnormal values and potentially clinically significant values will be flagged.  
A listing of lumbar puncture and CSF sample collection data other than CSF laboratory results 
(i.e. CSF volume collected, needle and gauge information, caffeine/smoking/alcohol use prior to 
CSF collection) will also be provided. 
 Vital Signs 
Summary statistics for actual values and change from baseline will be presented for each vital 
sign parameter (temperature, weight, pulse, respiration, systolic BP and diastolic BP) by dose 
group and visit. A listing of vital sign data will also be provided.  
Vital signs (temperature, pulse, systolic BP and diastolic BP) will also be examined to determine 
the incidence of potentially clinically relevant abnormalities.  The number of subjects evaluated 
and the number of subjects with potentially clinically relevant abnormalities will be presented.  
The criteria for potentially clinically relevant post-dosing abnormalities are shown in Table 2. 
Table 2: Criteria to determine potentially clinically relevant abnormalities in vital signs 
Vital Sign 
Criteria for Abnormalities 
Temperature 
>38°C or an increase from baseline of ≥1°C  
 
Pulse 
>120 beats per minute (bpm) or an increase from baseline of >20 
bpm  
<50 bpm or a decrease from baseline of >20 bpm  
Systolic Blood Pressure 
>180 mmHg or an increase from baseline of >40 mmHg  
<90 mmHg or a decrease from baseline of >30 mmHg  
Diastolic Blood Pressure 
>105 mmHg or an increase from baseline of >30 mmHg  
<50 mmHg or a decrease from baseline of >20 mmHg  
 


 
 
 
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 ECG 
The ECG test includes heart rate, PR interval, QRS interval, QT interval, QTc interval using 
Bazett’s formula, QTc interval using Fridericia’s formula, and RR interval. Summary statistics 
for actual values and change from baseline in each ECG parameter will be presented by dose 
group and visit. A listing of ECG data will be provided.   
The number and percentage of subjects with shifts from normal to each of the categorical values 
denoting an abnormal scan (abnormal not AE, abnormal AE) will be summarized by dose group.    
QTc (interval using Fridericia’s formula) will also be examined to determine the incidence of 
clinically relevant abnormalities.  The number of subjects evaluated and the number of subjects 
with clinically relevant abnormalities will be presented.  The criteria for clinically relevant post-
dosing abnormalities are:  
• Maximum increase from baseline QTcF > 30 to 60 ms 
• Maximum increase from baseline QTcF > 60 ms 
• Maximum post-baseline QTcF > 480 to 500 ms 
• Maximum post-baseline QTcF > 500 ms 
 Limited neurological examinations 
The number and percentages of the status in each assessment of general neurological 
examination (cranial nerves, coordination/cerebellar function, sensation upper/lower 
extremities), El Escorial, and each assessment of other reflexes (jaw jerk, Hoffman sign 
right/left, plantar response right/left) will be summarized by dose group and visit. The reflexes 
neurological examination of upper and lower extremities will be analyzed as continuous 
variables (0 = absent, 1 = trace, 2 = normal, 3 = brisk, 4 = clonus). The descriptive statistics will 
be summarized by dose group and visit. Plots of mean values by visit will be also generated. 
The motor neurological examination will be analyzed as continuous variable (0 = no contraction 
or can’t position limb; 1 = flicker or trace contraction, no movement; 2 = movement only with 
gravity eliminated; 3 = movement against gravity; 4 = movement against gravity and resistance; 
5 = normal strength). The Ashworth spasticity scale will also be analyzed as continuous variable 
(1 = normal; 2 = slight increase in tone; 3 = more marked increase in tone; 4 = considerable 
increase in tone; 5 = affected part rigid, immobile).  Summary statistics will be presented by dose 
group and visit.  Plots of mean values by visit will also be generated.  
Listings will also be provided with complete details for the neurological examinations. 


 
 
 
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 Columbia Suicide Severity Rating Scale (C-SSRS) 
The details of derivation and imputation for C-SSRS is described in Appendix A. The following 
analyses on C-SSRS measurements will be conducted: 
• Descriptive summary of subjects who answered “Yes” to any question 1-12 as well as 
subjects who had suicidal ideation or suicidal behavior at baseline and at any post-
baseline visit. The denominator for baseline summary is the number of subjects who were 
dosed and had baseline assessment; the denominator for post-baseline summary is the 
number of subjects who were dosed and had at least one post-baseline assessment for 
each question. 
• Descriptive summary of subjects who had treatment-emergent suicidal ideation, subjects 
who had new suicidal ideation as well as subjects who had worsening suicidal ideation. 
The denominator is the number of dosed subjects with both baseline and at least one post-
baseline suicidal ideation assessment. 
• Descriptive summary of subjects who had treatment-emergent suicidal behavior. The 
denominator is the number of subjects who answered “No” to all suicidal behavior 
questions at baseline and had at least one post-baseline suicidal behavior assessment.  
Listing of subjects having treatment-emergent suicidal ideation will be provided. Subjects who 
had new suicidal ideation and subjects who had worsening suicidal ideation will be flagged. The 
listing will display both baseline and post-baseline Suicidal Ideation Scores for each subject. 
Listing of subjects having treatment-emergent suicidal behavior will also be provided.  
2.5 
Pharmacokinetic Data 
The PK population will be used for the analyses of the PK data.  
Values below limit of quantitation (BLQ) are set to half of the lower limit of quantitation 
(LLOQ, 1 ng/mL) at day 1 pre-dose rather than zero so that geometric means can be calculated. 
Values that are BLQ at all other visits will also be set to half of LLOQ (1 ng/mL) in calculations. 
Both plasma and CSF BIIB067 concentrations will be listed and summary statistics will be 
presented for each visit. Summary statistics will also include both the arithmetic and geometric 
means with corresponding standard errors. Plots of arithmetic and geometric mean 
concentrations of BIIB067 versus time will be provided, including standard error bars. Spaghetti 
plots will be presented for each BIIB067 group to show individual subjects throughout all visits. 
These will include both pre-dose and post-dose visits. Both the geometric mean and the median 
for the dose group will also be plotted on the spaghetti plots. 


 
 
 
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The BIIB067 concentrations will be used to calculate the following parameters at Day 1 using 
non-compartmental methods by the PK Scientist:  AUC[0-24h], Cmax, Tmax. Summary 
statistics will be provided for these PK parameters.  
2.6 
Pharmacodynamic Data 
The PD population will be used for the analyses of the PD/biomarker data.  
The following PD biomarkers will be summarized: SOD1 protein in CSF and the neurofilament 
levels in both the CSF and plasma. For SOD1 protein, the overall protein level will be analyzed. 
For neurofilament, the phosphorylated axonal neurofilament heavy chain (p-NFH) will be 
analyzed. Values that are BLQ will be set to half of LLOQ (15.6 ng/mL for SOD1 and 7.46 
pg/mL for pNFH).   
Descriptive statistics for the PD data at each visit, and ratio to baseline will be summarized by 
dose group. The summary statistics will include arithmetic mean and SD for the ratio to baseline 
as well as the geometric mean ratio and corresponding standard error. The geometric mean ratio 
will be obtained by back-transforming change from baseline on log transformed data. 
Plots of arithmetic mean ratio to baseline will be presented as well as plots of geometric mean 
ratio to baseline with standard error bars. Plots of the geometric mean and standard error at each 
visit will also be presented.  
Listings of individual data will also be provided. 
Spaghetti plots of actual values and ratio to baseline will be presented for each treatment group 
to show individual subjects throughout all visits. Both the geometric mean and the median for the 
dose group will also be plotted on the spaghetti plots.  
2.7 
Immunogenicity Data 
The immunogenicity population, as defined in Section 2.2.1, will be used for all analyses of 
immunogenicity data.  
• For immunogenicity, the baseline value is defined as the latest immunogenicity data 
collected at any time prior to the first dose.  If no immunogenicity data are collected prior 
to the first dose, the baseline value is missing and will be imputed as anti-drug antibody 
negative for immunogenicity analyses.  
• Subjects with at least one confirmed post-treatment positive result will be considered 
positive for anti-drug antibodies if their baseline result is negative. 


 
 
 
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• Subjects where none of the post-treatment samples were positive for anti-drug antibodies 
will be considered negative regardless of their baseline result 
• For subjects that are confirmed positive at baseline and have at least one post-treatment 
sample with a ≥ 2 fold increase in titer will be considered positive for anti-drug 
antibodies. Subjects that are positive at baseline, with subsequent post-treatment samples 
titers that are within 2 fold will be considered negative for anti-drug antibodies 
• Numbers and percentage of subjects who develop antibodies will be determined and 
summarized by treatment groups and timepoint.  
The same summary will be provided for subjects with positive baseline results and for subjects 
with negative or missing baseline results, separately.  
2.8 
Clinical Function Data 
The clinical function set will be used for all analyses of clinical functions.  
Unless stated otherwise, baseline data are defined as the data collected prior to the time and/or on 
the date of first dose, which is usually the same day as the Day1/Baseline visit. If there is more 
than one value on/before the date of the first dose, the non-missing value closest to and prior to 
the first dose will be used as the baseline value. For 
 HHD 
 data were collected 
at Screening and not Day 1 so baseline values for endpoints on these assessments will be taken 
from the Screening visit. 
Descriptive statistics of clinical function endpoints will be presented for Part A based on 
observed data only; missing data at a visit level will not be imputed for Part A. When a placebo 
group is involved in an analysis, all subjects receiving placebo will be combined to form placebo 
control group.  The derivation and imputation for each clinical function endpoint is described in 
Appendix B. Imputation will only be performed within an endpoint and visit for example if there 
are missing responses to some of the individual questions on a scale at a given visit, the endpoint 
may only be derived if there are a certain number of individual items/components with available 
data. Specific details are provided for each assessment/scale in Appendix B, as this differs across 
assessments/scales. 
Any assessments of clinical functions at unscheduled visits will not be used in the analysis but 
will be listed.  
The endpoints for clinical function data are given in Table 3. 
For each endpoint listed, descriptive statistics of actual values and changes from baseline at each 
visit will be summarized by dose group based on observed data.  Plots of mean values and mean 


 
 
 
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changes from baseline by visit will also be generated.  Spaghetti plots of actual values and 
changes from baseline for ALSFRS-R total score, HHD overall megascore, and percent predicted 
SVC will be presented for each dose group to show individual subjects throughout all visits. The 
mutation subtype will also be indicated for each subject on the spaghetti plots. Listings of 
individual data on clinical functions will also be provided. 
Table 3: Clinical function endpoints for Part A 
Clinical Function 
Endpoint 
ALSFRS-R 
- 
Total Score 
- 
Functional domain scores (bulbar function, fine 
motor skills, gross motor skills, respiratory 
function) 
SVC 
- 
Percent predicted SVC 
HHD 
- 
HHD Megascore 
- 
Muscle strength for each of 16 muscles 
 
 
 
 
 


 
 
 
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3. Part B: Multiple-Ascending-Dose (MAD) Evaluation 
3.1 
Study Design 
Part B will be a randomized, double-blind, placebo-controlled, MAD evaluation of up to 4 dose 
levels of BIIB067 administered up to 5 times, over approximately 3 months, to up to 
approximately 48 subjects with SOD1-ALS. Each dose level will be assessed in cohorts of 12 
subjects: 3 subjects will be administered placebo, and 9 subjects will be administered BIIB067 at 
20, 40, 60 or 100 mg. 
The duration of study participation for each subject enrolled in Part B will be up to 
approximately 31 weeks, which will include a screening period up to 7-weeks, a 12-week 
treatment period (consisting of 3 loading doses of BIIB067, administered approximately once 
every 2 weeks, followed by 2 maintenance doses of BIIB067, administered approximately once 
every 4 weeks), and a 12-week follow-up period. Figure 4 is the study schematic and Table 3 
shows the schedule of assessments.




 
 
 
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Table 4: 
Schedule of Activities:  Part B – Multiple Ascending Dose 
Tests and Assessments 
Screening 
Dosing Inpatient Period 
Dosing 
Days 15, 
29, 57 & 
85 
(±3 
days) 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 
to Day -1 
Day 1 
Day 2 
24 (±1) 
Postdos
e 
Days 83, 22, 
36, 64, 92, and 
106 
(±3 days) 
Days 50 & 
78 via 
Telephone 
(±3 days) 
Day 169 
(±3 days) 
/Early 
Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Informed Consent (main) 
X 
X4 
 
 
 
 
 
 
 
Medical History 
 
X 
X 
 
 
 
 
 
 
Clinical Laboratory Samples 
to Verify Eligibility5 
 
X 
 
 
 
 
 
 
 
FVC 
 
X 
 
 
 
 
 
 
 
Admission to Inpatient 
Facility 
 
 
X 
 
 
 
 
 
 
Physical Examination 
 
X 
X 
 
X6 
X6 
X6 
 
X6 
Weight 
 
X 
X 
 
 
 
 
 
X 
Height 
 
X 
 
 
 
 
 
 
 
Limited Neurological 
Examination (including the 
MMSE)7 
 
X 
X 
X8 
X 
X9 
X 
 
X 


 
 
 
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Tests and Assessments 
Screening 
Dosing Inpatient Period 
Dosing 
Days 15, 
29, 57 & 
85 
(±3 
days) 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 
to Day -1 
Day 1 
Day 2 
24 (±1) 
Postdos
e 
Days 83, 22, 
36, 64, 92, and 
106 
(±3 days) 
Days 50 & 
78 via 
Telephone 
(±3 days) 
Day 169 
(±3 days) 
/Early 
Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Vital Signs (temperature, 
blood pressure, pulse rate, 
respiratory rate) 
 
X 
X 
X10 
X 
X11 
X 
 
X 
12-Lead ECG12 
 
X 
X 
X10 
X 
X11 
X 
 
X 
C-SSRS Questionnaire 
 
 
X 
 
 
 
 
 
X13 
Urine Pregnancy Test14 
 
X 
X 
 
 
X15 
 
 
X 
FSH Test16 
 
X 
 
 
 
 
 
 
 
Randomization 
 
 
X 
 
 
 
 
 
 
Study Drug Administration 
 
 
 
X 
 
X 
 
 
 
SVC 
 
 
X 
 
 
X15 
 
 
X 
ALSFRS-R 
 
X 
X 
 
 
X 
X17 
 
X 


 
 
 
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Tests and Assessments 
Screening 
Dosing Inpatient Period 
Dosing 
Days 15, 
29, 57 & 
85 
(±3 
days) 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 
to Day -1 
Day 1 
Day 2 
24 (±1) 
Postdos
e 
Days 83, 22, 
36, 64, 92, and 
106 
(±3 days) 
Days 50 & 
78 via 
Telephone 
(±3 days) 
Day 169 
(±3 days) 
/Early 
Termination 
Visit 
Predose 
Dosing/ 
Postdose 
HHD 
 
X 
 
 
 
 
X17 
 
X 
Clinical Laboratory Samples 
for Hematology, Coagulation, 
Chemistry, and Urinalysis 
 
X 
X 
 
X 
X 
 
 
X 
CSF Samples18 
 
 
X 
 
 
X19 
X20 
 
X 
Blood Samples for Plasma 
anti-BIIB067 Ab 
 
 
X 
 
 
 
X 
 
X 
Blood Samples for 
Biomarkers 
 
 
X 
 
 
X 
X22 
 
X 


 
 
 
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Tests and Assessments 
Screening 
Dosing Inpatient Period 
Dosing 
Days 15, 
29, 57 & 
85 
(±3 
days) 
Follow-Up 
V11 
≤21 days 
before V2 
V22 
Day -28 
to Day -1 
Day 1 
Day 2 
24 (±1) 
Postdos
e 
Days 83, 22, 
36, 64, 92, and 
106 
(±3 days) 
Days 50 & 
78 via 
Telephone 
(±3 days) 
Day 169 
(±3 days) 
/Early 
Termination 
Visit 
Predose 
Dosing/ 
Postdose 
Blood Samples for Plasma PK 
 
 
X 
X23 
X 
X24 
X 
 
X 
Discharge from Inpatient 
Facility 
 
 
 
 
X 
 
 
 
 
AE, and Concomitant Therapy 
and Procedures Recording 
 
 
-------------------------------------------------X (ongoing) ------------------------------------------ 
SAE Recording 
-------------------------------------------------------------------X (ongoing)--------------------------------------------------- --------- 
Ab = antibody; AE = adverse event; ALS = amyotrophic lateral sclerosis; 
 
ALSFRS-R = Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised; CSF = cerebrospinal fluid; C-SSRS = Columbia Suicide Severity Rating Scale; 
DNA  = deoxyribonucleic acid; ECG = electrocardiogram, 
; 
 
 FSH = follicle-stimulating hormone; FVC= forced vital capacity; HHD = handheld dynamometry; MMSE = Mini-
Mental State Examination; 
 
; PK = pharmacokinetic(s); RNA = ribonucleic acid; 
SAE = serious adverse event; 
 SOD1 = superoxide dismutase 1; SVC = slow vital capacity; V = visit; 
 
 
1 Required only for subjects without a prior documentation of SOD1 mutation.  Results must be available before performing Screening Visit 2 assessments. 
2 Screening assessments can be performed over ~2 days (need not be consecutive) to minimize subject burden. 


 
 
 
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3 Subjects may, at the discretion of the Investigator, have the option of home visits for non-dosing visits that do not require CSF collection or strength and 
electrophysiological measures, which are visits on Days 8, 36, and 64. 
4 Not required if collected during Screening Visit 1. 
5 Including blood samples for human immunodeficiency virus, hepatitis C virus, and hepatitis B virus tests, and platelet and coagulation tests.  Coagulation tests 
may be repeated at the local laboratory once if, in the opinion of the Investigator, values of the initial tests are only slightly out of range.  Subjects with 
nonclinically significant and stable out-of-range values for coagulation tests may be eligible to enroll in the study at the discretion of the Investigator, and after 
a consultation with the Sponsor. 
6 Limited physical examination will be conducted at the Investigator's discretion. 
7 The limited neurological examination pertains to cranial nerves, coordination/cerebellar function, reflexes, motor, and MMSE. 
8 To be assessed at 3 and 6 hours postdose. 
9 To be assessed predose, and 3 and 6 hours postdose. 
10 To be assessed just prior to drawing PK blood samples at 2 and 4 hours postdose. 
11 To be assessed just prior to drawing PK blood samples at predose, and 2 and 4 hours postdose. 
12 Triplicate 12-lead (paper) ECGs will be obtained after the subject has rested in a supine position for at least 10 minutes.  The first ECG will be interpreted, and 
the last 2 will be checked for consistency and quality. 
13 Use “Since Last Visit” version of C-SSRS. 
14 For women of childbearing potential only. 
15 To be performed predose. 
16 To confirm postmenopausal status in postmenopausal female subjects. 
17 Day 22 and Day 92 for 
 HHD; Day 92 for ALSFRS-R 
 
18 Lumbar puncture (LP) will be performed to collect CSF samples for PK, pharmacodynamic, safety, and biomarker analysis.  The results of the most recent (i.e., 
obtained at Screening or other visit during the study) coagulation tests and platelet count must be reviewed before each LP can be performed.  Should the 
results suggest, in the opinion of the Investigator, that an LP may be safely performed, then no further laboratory values need to be reviewed.  However, should, 
in the opinion of the Investigator, repeat coagulation and platelet tests be clinically indicated, then these tests may be done locally to facilitate timely review.  
Results of any repeat tests must be available before the LP can be performed. 
19 To be collected predose.  Subjects will remain under observation in the clinic for approximately 6 hours after the LP procedure and will receive a safety follow 
-up telephone call ~24 hours after the procedure. 
20 To be collected on Day 106 only.  Subjects will remain under observation in the clinic for approximately 1 hour after the LP procedure and will receive a safety 
follow-up telephone call ~24 hours after the procedure. 


 
 
 
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22 Day 106 only. 
23 To be collected at 1, 2, 4, and 6 hours postdose. 
24 To be collected predose at each visit; collected at 1, 2, 4, and 6 hours postdose for Day 85 only. 


 
 
 
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3.2 
Statistical Methods: General Considerations  
Descriptive summary statistics will be presented for all primary, secondary and exploratory 
endpoints collected. Unless otherwise specified, for continuous endpoints, the summary statistics 
will generally include: number of subjects with data, mean, standard deviation, median, first and 
third quartiles and range.  For categorical endpoints, the summary statistics will generally 
include:  number of subjects with data, and the percentage of those with data in each category.  
Placebo patients across cohorts 5 to 8 in Part B will be combined for Part B summaries. All 
summaries will be presented by dose group unless otherwise specified. Some summaries may 
also present the overall population combining both placebo and active dose groups. 
The statistical software, SAS® version 9.4 or above, will be used for all summaries and statistical 
analyses.  
As a general rule, any visit/dose group combination that only has data for 1 patient will not be 
presented in group plots. The data collected at telephone follow-up visits after Day 169 visit (i.e. 
ALSFRS-R) at United Kingdom sites will be also excluded from group plots and spaghetti plots. 
However, all data will be summarized and listed, unless otherwise specified. 
 Analysis Populations 
3.2.1.1 ITT Population 
The ITT (Intention-to-Treat) population is defined as all randomized subjects who receive at 
least 1 or a part of 1 dose of study treatment (BIIB067 or placebo) in Part B. In case of any 
subjects who are mis-randomized, the ITT analysis will be based on treatment assignment at the 
time of randomization.  
3.2.1.2 Safety Population 
The safety population is defined as the ITT population of subjects in Part B. This will be the 
primary population for the analysis of safety endpoints. In the case of any subjects who are mis-
randomized, the any analyses based on the safety population will be based on actual treatment 
received. If a population is not specified otherwise for an analysis of safety, the safety population 
should be used. 
3.2.1.3 Pharmacokinetic (PK) Population 
The PK population is defined as the subset of the ITT population of subjects with at least 1 post-
dose PK measurement in Part B. 


 
 
 
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3.2.1.4 Pharmacodynamic (PD) Population 
The PD population is defined as the subset of the ITT population of subjects with at least 1 post-
dose PD measurement in Part B.  
3.2.1.5 Clinical Function Set 
The clinical function set is defined as the subset of ITT population of subjects who have at least 
1 post-dose clinical function measurement in Part B. Subjects will be analyzed in the dose group 
to which they are randomized. This will be the population for the analysis of clinical function 
endpoints.  
3.2.1.6 Immunogenicity Population 
The analysis population for immunogenicity is defined as all subjects in the safety population 
who have at least 1 post-dose sample evaluated for immunogenicity in Part B.  
 Data from Early Withdrawal or Unscheduled Visits 
For subjects who are early terminated (ET), EOS visit is defined as the scheduled follow-up visit 
after ET visit.  
Any assessments of clinical functions at unscheduled visits will not be used in the analysis but 
will be listed.  
3.3 
Study Subjects 
 Subject Accountability  
The number (and percentage) of subjects randomized; dosed; completed the treatment; 
completed the study; completed the study but missed one or more doses; discontinued treatment 
and the reasons for discontinuation; and withdrew from study early and the reasons for 
withdrawal will be summarized in a table. The number of subjects who enrolled and completed 
both Parts A and B will be summarized.  
A listing of subjects who discontinued treatment/withdrew from study and the associated reasons 
for discontinuation/withdrawal will be presented.  
The number (and percentage) of subjects randomized by country and site, the number (and 
percentage) of subjects who completed the study by country and site, and number (and 
percentage) of subjects by analysis population will be summarized by dose group and for all 
subjects. 


 
 
 
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 Demography and Baseline Disease Characteristics 
All demographics and ALS disease history data will be summarized for the ITT population. 
Demographic data, including age (years), age category (18-<35,35-<50, 50-<65, ≥65), gender, 
ethnicity, race, height, weight and body mass index (BMI) will be summarized by dose group 
and for all subjects.  BMI will be calculated as weight (kg) / height2 (m2).  
ALS disease history will also be summarized by dose group and for all subjects using descriptive 
statistics.  These include form of ALS, mutant genes among familial ALS, SOD1 mutation 
subtype (variant), time since ALS symptom onset, site of onset, time since ALS diagnosis, pre-
randomization ALSFRS-R slope, disease progression type (“fast progressing disease” vs “other”) 
and riluzole usage/duration. Additionally, a listing of individual subjects with known SOD1 
mutation types will be provided. 
Time since ALS symptom onset will be calculated in months as (date of first dose received – 
date of ALS symptom onset)/30.4375. Time since ALS diagnosis will be calculated in months as 
(date of first dose received – date of ALS diagnosis)/30.4375. For the purpose of these 
calculations, partial dates for ALS symptom onset or ALS diagnosis will be imputed as follows: 
missing day will be imputed with 15th and missing month/day will be imputed with January 
15th.  
The pre-randomization ALSFRS-R slope will be calculated using the ALSFRS-R score at 
baseline (Day 1) i.e. Baseline ALSFRS-R score – maximum possible score of 48/duration of 
symptom onset, where duration of symptom onset will be calculated as (date of baseline 
ALSFRS-R score – date of symptom onset)/30.4375. Partial dates for symptom onset will be 
handled as defined above.  
For disease progression type, subjects are classified as “fast progressing disease” if they have 
one of the a priori-defined fast-progressing SOD1 mutations and a pre-randomization ALSFRS-
R slope decline of at least 0.2 points per month; all other subjects are characterized as being 
“other”. The list of fast-progressing SOD1 mutations was determined in a blinded fashion 
following the interim analysis of cohorts 1 to 7 but prior to the unblinding and interim analysis of 
Cohort 8.  The mutations recorded for all subjects in Part B were reviewed to assess which were 
classified as fast-progressing SOD1 mutations through genetic and literature review: (identified 
fast-progressing SOD1 mutations from Part B cohorts 5 to 8:  p.Ala5Val, p.Arg116Gly, 
p.Leu107Val). 
Medical history will be classified using MedDRA version 22.0.  A summary of medical history 
by system organ class and preferred term will also be provided. 


 
 
 
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 Extent of Exposure 
Extent of exposure to study treatment will be summarized for the safety populations by dose 
group.  
Number of patients who received 1, 2, 3, 4, or 5 doses will be summarized by dose group, as will 
total cumulative dose in mg.  
Study drug compliance percentage up to the last dose of study drug received will be defined as 
the number of doses actually received divided by the number of doses that the subject is expected 
to receive during the study period and will be summarized. For subjects who withdrew from 
study early, the number of expected doses is the planned number of doses before the time of 
withdrawal.  
Separate listings will be provided showing what subjects were randomized to as well as study 
drug administration which will include lot numbers. 
Duration of exposure and time on study will be summarized descriptively by dose group. 
Duration of exposure will be calculated as (last dose date – first dose date + 1) in days and time 
on study will be calculated as (end of study date – first dose date + 1) in days. 
 Concomitant Medications and Non-Drug Treatments/Procedures 
Concomitant medications will be coded using the World Health Organization (WHO) dictionary 
WHODRUG (March 2019) and concomitant non-drug treatments/procedures using the Medical 
Dictionary for Regulatory Activities (MedDRA) version 22.0. 
Medications and non-drug treatments are considered concomitant if they are taken during the 
study. This includes medications/treatment/procedures that were started prior to the date and 
time of first dose of study drug if their use continued on or after the date and time of first dosing. 
If the start date is available but start time is missing and the medication/non-drug treatment start 
date is the same as the first dose date, the medication/non-drug treatment will be considered 
concomitant. Similarly, if the stop date is available but stop time is missing and the 
medication/non-drug treatment stop date is the same as the first dose date, the medication/non-
drug treatment will also be considered concomitant. Medications/therapies with missing start or 
stop dates and times, will also be considered as concomitant in the following situations: 
• If both the start and stop dates and times of a medication/treatment/procedure are 
missing; 


 
 
 
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• If the start date and time of a medication/treatment/procedure is missing and the stop date 
and time of the medication/therapy occurred on or after the date and time of first dose of 
study drug; 
• If the start date and time of a medication/treatment/procedure therapy occurred prior to 
the date and time of first dose of study drug and the stop date and time of the 
medication/treatment/procedure is missing and the medication/treatment/procedure is 
listed as ongoing; 
If the start date and time of a medication/treatment/procedure occurred prior to the date and time 
of first dose of study drug and the stop date and time of the medication/treatment/procedure is 
missing and the medication/therapy is not listed as ongoing, then the 
medication/treatment/procedure will not be considered as concomitant. 
The number and percentage of subjects taking any concomitant medications will be summarized 
by dose group for the safety population. The number and percentage of subjects taking any 
concomitant non-drug treatments will also be summarized by dose group for the safety 
population. 
 Protocol Deviations 
Protocol deviations identified during site monitoring will be captured in a protocol deviation log. 
All protocol deviations will be listed and a summary of major protocol deviations by dose group 
will also be provided. 
3.4 
Safety Data  
The safety population will be used for the analyses of the safety data. Safety data will be 
summarized using descriptive statistics by dose group.  
 Adverse Events 
All AEs will be classified using MedDRA version 22.0.  All AEs will be listed but only 
treatment emergent AEs will be summarized, where treatment emergence will be relative to the 
first dose of study drug. A treatment emergent AE/SAE is defined as any AE/SAE with an onset 
date and time that is on or after the first dose of study drug or any pre-existing condition that has 
worsened in severity after the first dose of study drug.  In case of missing dates, any AE/SAE 
with both a missing onset date and resolution date, or any AE/SAE with a missing onset date and 
a resolution date which is after the first dose of study drug, will be considered treatment 
emergent. If the onset date is available but onset time is missing and the AE onset date is the 
same as the first dose date the AE will be considered treatment emergent. The incidence of 
treatment emergent AEs will be summarized by dose group as follows: 


 
 
 
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• by MedDRA preferred term 
• by primary system organ class (SOC) and MedDRA preferred term 
• by maximum toxicity grade, primary SOC and MedDRA preferred term 
• related AEs by primary SOC and MedDRA preferred term 
• AEs related to lumbar puncture by primary SOC and MedDRA preferred term 
• AEs led to discontinuation of study drug by primary SOC and MedDRA preferred term 
• AEs led to withdrawal from study by primary SOC and MedDRA preferred term 
• AEs led to drug interrupted by primary SOC and MedDRA preferred term 
 
For the AE summary by primary system organ class and preferred term, subjects will be counted 
only once within each primary SOC/MedDRA preferred term. For the summary of AEs by 
maximum toxicity grade, primary system organ class and preferred term, subjects will be 
counted only once within each primary SOC/MedDRA preferred term and will only be counted 
under the maximum toxicity grade. For the summary of related AEs, if the relationship is 
missing then this will be summarized as unknown. 
The most common treatment emergent AEs (occurring in 3 or more subjects in any treatment 
group; occurring in 2 or more subjects in any active treatment group compared to placebo) will 
be presented by SOC and MedDRA preferred term.  
Listings of the following events will be produced.   
• AEs led to discontinuation of study drug 
• AEs led to withdrawal from study 
• AEs led to drug interrupted 
 Listing of deaths will be provided if applicable. 
SAEs will also be listed and summarized by primary SOC and MedDRA preferred term.  
 Laboratory Data 
Laboratory data will be evaluated to determine the incidence of abnormalities that emerge during 
the course of the study.  Changes in laboratory evaluations will be presented relative to baseline, 
which is defined as the closest visit prior to the subject starting treatment. 
The following clinical laboratory parameters are assessed in the protocol: 


 
 
 
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• Hematology panel: complete blood count with differential (hematocrit, hemoglobin, 
platelets, red blood cell count [RBC], white blood cell count [WBC], basophils, 
eosinophils, lymphocytes, monocytes, neutrophils) 
• Blood chemistry panel: albumin, total bilirubin, direct bilirubin, alkaline phosphatase, 
alanine aminotransferase (ALT) (SGPT), aspartate aminotransferase (AST) (SGOT), 
gamma-glutamyl transferase (GGT), sodium, potassium, calcium, chloride, phosphate, 
blood urea nitrogen (BUN), creatinine,  uric acid, bicarbonate (CO2), glucose, total 
protein. 
• Urinalysis:  blood, glucose, protein, and microscopic examination if abnormal 
• CSF analysis: RBC, WBC, protein, glucose. 
• Coagulation: PT (prothrombin time), aPTT (activated partial thromboplastin time), and 
INR (international normalized ratio). 
If multiple samples are collected at the same visit, the samples collected at the earliest date/time 
will be analyzed. For CSF laboratory parameters, tube 2 results will be analyzed if available.  
Baseline value is defined as data collected which are prior to and/or on the date of the first dose, 
usually also the same day as the Day 1 visit.  If there is more than one value on or before Day 1, 
then the last non-missing value prior to (including on) the date of first dose will be used as the 
baseline value.  
Each hematology, blood chemistry, coagulation and CSF laboratory parameter will be flagged as 
“low” or “high” relative to the parameter’s normal range or as “unknown” if no result is 
available.  For each urinalysis laboratory parameter, the number and percentage of subjects 
experiencing post-dosing shifts to ‘high’ (positive) will be summarized. For each hematology, 
blood chemistry, coagulation and CSF parameter, the number and percentage of subjects 
experiencing post-dosing shifts to ‘low’ or ‘high’ will be summarized.  In each summary, the 
denominator for the percentage is the number of subjects at risk for the shift.  The number at risk 
for the shift to low is the number of subjects whose baseline value was not low and who had at 
least one post-baseline value.  The number at risk for the shift to high is the number of subjects 
whose baseline value was not high and who had at least one-post baseline value.  Subjects will 
be counted only once for each parameter and each shift regardless of how many post-dosing 
assessments had that type of shift.   
Summary statistics for actual values and change from baseline in laboratory values will be 
summarized by dose group and visit.  Line plots for chemistry, hematology and CSF showing 
mean value for each dose group at each visit will also be presented. 


 
 
 
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To evaluate potential serious hepatotoxicity subjects with a post-baseline AST and/or ALT value 
≥3 times the upper limit of normal (ULN) and a post-baseline bilirubin value >2 times ULN at 
any time, not necessarily concurrent, will be listed with their values. In addition, a plot will be 
presented with each subject’s maximum post-baseline AST or ALT value relative to the ULN 
against the subject’s maximum post-baseline bilirubin value relative to the ULN; values do not 
have to be concurrent.  
Listings of all chemistry, hematology, coagulation, CSF, urinalysis values and urine pregnancy 
test will be provided.  Abnormal values and potentially clinically significant values will be 
flagged.  
Subjects with at least one post-baseline CSF WBC values >5 will be plotted in a spaghetti plot. 
A similar plot will be provided for subjects who have a post-baseline CSF WBC value >10. 
Corresponding listings will also be presented with AEs that occurred at any time on or after the 
subject had a post-baseline CSF WBC value >5 and any time on or after the subject had a post-
baseline CSF WBC value >10. Further investigation may be performed to look at the relationship 
between elevation in CSF WBC values and AEs. 
A summary table and listing of lumbar puncture and CSF sample collection data other than CSF 
laboratory results (i.e. lumbar puncture position, number of attempts, interspaces, additional 
guidance used, CSF volume collected, needle and gauge information, caffeine/smoking/alcohol 
use prior to CSF collection) will also be provided. 
 Vital Signs 
Summary statistics for actual values and change from baseline will be presented for each vital 
sign parameter (temperature, weight, pulse, respiration, systolic and diastolic blood pressure) by 
dose group and visit. A listing of vital sign data will also be provided.  
Vital signs (temperature, pulse, systolic and diastolic blood pressure) will also be examined to 
determine the incidence of potentially clinically relevant abnormalities.  The number of subjects 
evaluated and the number of subjects with potentially clinically relevant abnormalities will be 
presented.  The criteria for potentially clinically relevant post-dosing abnormalities are shown in 
Table 2 section 2.4.3. 
 ECG 
The ECG test includes heart rate, PR interval, QRS interval, QT interval, QTc interval using 
Bazett’s formula, QTc interval using Fridericia’s formula, and RR interval. Summary statistics 
for actual values and change from baseline in each ECG parameter will be presented by dose 
group and visit.  A listing of ECG data will be provided.  


 
 
 
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The number and percentage of subjects with shifts from normal to each of the categorical values 
denoting an abnormal scan (abnormal not AE, abnormal AE) will be summarized by dose group.     
QTc (interval using Fridericia’s formula) will also be examined to determine the incidence of 
clinically relevant abnormalities.  The number of subjects evaluated and the number of subjects 
with clinically relevant abnormalities will be presented.  The criteria for clinically relevant post-
dosing abnormalities are:  
• Maximum increase from baseline QTcF > 30 to 60 ms 
• Maximum increase from baseline QTcF > 60 ms 
• Maximum post-baseline QTcF > 480 to 500 ms 
• Maximum post-baseline QTcF > 500 ms 
 Mini-Mental State Exam (MMSE) 
MMSE is collected for Part B subjects only. Summary statistics for actual values and change 
from baseline of the total score of MMSE will be presented for each visit by dose group. When 
there are multiple assessments during a single visit, the minimal value will be taken as the value 
for that visit. A listing of MMSE data for individual patients will also be provided.  
 Limited neurological examinations 
The number and percentages of the status in each assessment of general neurological 
examination (cranial nerves, coordination/cerebellar function, sensation upper/lower 
extremities), El Escorial, and each assessment of other reflexes (jaw jerk, Hoffman sign 
right/left, plantar response right/left will be summarized by dose group and visit. The reflexes 
neurological examination of upper and lower extremities will be analyzed as continuous 
variables (0 = absent, 1 = trace, 2 = normal, 3 = brisk, 4 = clonus). The descriptive statistics will 
be summarized by dose group and visit. Plots of mean values by visit will be also generated. 
The motor neurological examination will be analyzed as continuous variable (0 = no contraction 
or can’t position limb; 1 = flicker or trace contraction, no movement; 2 = movement only with 
gravity eliminated; 3 = movement against gravity; 4 = movement against gravity and resistance; 
5 = normal strength). The Ashworth spasticity scale will also be analyzed as continuous variable 
(1 = normal; 2 = slight increase in tone; 3 = more marked increase in tone; 4 = considerable 
increase in tone; 5 = affected part rigid, immobile). Summary statistics will be presented by dose 
group and visit.  Plots of mean values by visit will also be generated.  
Baseline values will be taken from Day 1 predose unless an entire section of the neurological 
exam (i.e. general, reflexes, motor) is missing or not done, in which case for that specific section 
baseline will be taken from the Screening visit for all items within that section of the exam.   


 
 
 
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Listings will also be provided with complete details for the neurological examinations. 
 Columbia Suicide Severity Rating Scale (C-SSRS) 
The details of derivation and imputation for C-SSRS is described in Appendix A. The following 
analyses on C-SSRS measurements will be conducted: 
• Descriptive summary of subjects who answered “Yes” to any question 1-12 as well as 
subjects who had suicidal ideation or suicidal behavior at baseline and at any post-
baseline visit. The denominator for baseline summary is the number of subjects who were 
dosed and had baseline assessment; the denominator for post-baseline summary is the 
number of subjects who were dosed and had at least one post-baseline assessment for 
each question. 
• Descriptive summary of subjects who had treatment-emergent suicidal ideation, subjects 
who had new suicidal ideation as well as subjects who had worsening suicidal ideation. 
The denominator is the number of dosed subjects with both baseline and at least one post-
baseline suicidal ideation assessment. 
• Descriptive summary of subjects who had treatment-emergent suicidal behavior. The 
denominator is the number of subjects who answered “No” to all suicidal behavior 
questions at baseline and had at least one post-baseline suicidal behavior assessment.  
Listing of subjects having treatment-emergent suicidal ideation will be provided. Subjects who 
had new suicidal ideation and subjects who had worsening suicidal ideation will be flagged. The 
listing will display both baseline and post-baseline Suicidal Ideation Scores for each subject. 
Listing of subjects having treatment-emergent suicidal behavior will also be provided.  
3.5 
Pharmacokinetic Data 
The PK population will be used for the analyses of the PK data.  
Values below limit of quantitation (BLQ) are set to half of the lower limit of quantitation 
(LLOQ, 1 ng/mL) at day 1 pre-dose rather than zero so that geometric means can be calculated. 
Values that are BLQ at all other visits will also be set to half of LLOQ (1 ng/mL) in calculations. 
Both plasma and CSF BIIB067 concentrations will be listed and summary statistics will be 
presented for each visit. Summary statistics will also include both the arithmetic and geometric 
means with corresponding standard errors. Plots of arithmetic and geometric mean 
concentrations of BIIB067 versus time will be provided, including standard error bars. The plots 
will be repeated for plasma BIIB067 concentrations separately for all timepoints at Day 1 and 
Day 85.  Spaghetti plots will be presented for each BIIB067 group to show individual subjects 


 
 
 
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throughout all visits. These will include both pre-dose and post-dose visits. Both the geometric 
mean and the median for the dose group will also be plotted on the spaghetti plots. 
The BIIB067 concentrations will be used to calculate the following parameters at Day 1 and Day 
85 using non-compartmental methods by the PK Scientist:  AUC[0-24h], Cmax, Tmax. 
Summary statistics will be provided for these PK parameters.  
A summary of missing plasma and CSF BIIB067 concentrations will also be provided. 
3.6 
Pharmacodynamic Data 
The PD population will be used for the analyses of the PD/biomarker data.  
The following PD biomarkers will be summarized:  
• SOD1 protein in CSF. For SOD1 protein, the overall protein level will be analyzed.  
• Neurofilament levels in both the CSF and plasma. For neurofilament, the phosphorylated 
axonal neurofilament heavy chain (p-NFH) will be analyzed.  
Values that are BLQ will be set to half of LLOQ (15.6 ng/mL for SOD1 and 7.46 pg/mL for 
pNFH).   
Missing Data 
A summary of missing data for each PD biomarker will be presented. 
For both CSF SOD1 and p-NFH measurements, any post-baseline missing up to and including 
Day 85 will be imputed using 2 methods. Baseline and data beyond Day 85 will not be imputed. 
Primary method of imputation: Mixed Model for Repeated Measures (MMRM) 
The MMRM model will be used to impute missing values and to obtain a complete dataset for 
actual values for each PD biomarker. The MMRM model for actual values will be used for the 
purpose of presenting descriptive statistics only. Missing values will be replaced by predicted 
values from the model. The model for actual values will be performed on the log scale (i.e. log 
(post-baseline)). The model will include dose group, visit, treatment-by-visit interaction, baseline 
score i.e. log value, and baseline score-by-visit interaction terms, and adjust for the following 
covariate: disease progression type. Visits to Day 85 only will be included in the model.  
The MMRM model for log ratio to baseline will be used to impute missing values as well as for 
inference, analyzing longitudinal assessment on change from baseline values on log scale ((i.e 
log(post-baseline) – log(baseline)) up to Day 85 for each PD biomarker. The model will include 
dose group, visit, treatment-by-visit interaction, baseline score i.e. log value, and baseline score-
by-visit interaction terms, and adjust for the following covariate: disease progression type.  


 
 
 
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For the MMRM model, an unstructured covariance (UN) matrix will be used to model the 
within-subject variability. Model convergence will be checked. If the unstructured covariance 
model fails to converge with the default Newton-Rhapson algorithm, the Fisher scoring 
algorithm will be used to provide initial values of the covariance parameters. In the event that 
none of the above methods yield convergence, a structured covariance such as the heterogeneous 
first-order autoregressive (ARH(1)) structure will be used. 
The MMRM models specified above for actual values and ratio to baseline will also be applied 
on the subgroup analysis of disease progression type (other, fast). The model will be similar to 
that specified above for each subgroup level except disease progression type will not be included 
in the model. 
Secondary method of imputation: Last observation carried forward (LOCF) 
As a sensitivity analysis the LOCF method will be used as a conservative estimate. In the LOCF 
approach since baseline data will not be carried forward, if the first post-baseline visit is missing, 
it will remain missing after applying LOCF imputation. LOCF will be applied on actual values at 
each visit to provide a complete dataset. 
Descriptive statistics for imputed datasets 
Descriptive statistics for each PD biomarker at each visit and ratio to baseline will be 
summarized by dose group. The summary statistics will include arithmetic mean and SD for the 
ratio to baseline as well as the geometric mean ratio and corresponding standard error. The 
geometric mean ratio will be obtained by back-transforming change from baseline on log 
transformed data. Arithmetic means and geometric means will be presented for the actual values 
at each visit. The descriptive summaries will be presented overall and by disease progression 
type based on both MMRM imputed data as well as LOCF imputed data. 
The following plots over time will be presented for each PD biomarker for both sets of LOCF 
and MMRM imputed datasets (overall and by disease progression type): 
• Arithmetic mean ratio to baseline with standard error bars 
• Geometric mean ratio to baseline with standard error bars.  
• Geometric mean and standard error  
 
Listings of individual data will also be provided. 
 
 


 
 
 
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Statistical analysis 
The statistical analysis of PD biomarkers will be performed for Part B only. All statistical tests 
will be conducted at the nominal significance level of 0.1. CIs will be constructed at the 
traditional 95% confidence level. No adjustment for multiple testing will be performed. Nominal 
p-values will be presented. 
For both CSF SOD1 and p-NFH measurements, a 2-sample Wilcoxon rank sum test will be 
performed on the log scale for ratio to baseline values at Day 85 comparing each BIIB067 group 
vs. placebo group overall and for each disease progression type. This will be the primary method 
of analysis based on the MMRM imputed dataset.   
As sensitivity analysis the MMRM model for ratio to baseline will also be used for inference: 
For each PD biomarker least-squares (LS) means of each dose level at each visit as well as 
treatment differences between each dose level vs. placebo at each visit will be presented, along 
with 95% CI and p-values. The back-transformed LS means here represent geometric mean 
ratios compared to baseline, and the back-transformed LS means differences represent geometric 
mean ratios of the ratios compared to baseline between each BIIB067 dose level vs. placebo. 
Results will be presented overall, and by disease progression type. These geometric mean ratios 
will also be plotted overall and by disease progression type.  
Similarly, a MMRM model will be performed on the LOCF imputed dataset for each PD 
biomarker. The model will be specified as detailed above for overall and by disease progression 
type. Results will be tabulated but not plotted. 
In addition, relationships between PK and PD biomarkers and between different PD biomarkers 
will be examined using scatter plots, including the list below. The correlation coefficient 
(Spearman) will also be generated by dose group and for overall. The scatter plots and 
correlation coefficient tables will be repeated for disease progression type subgroups. These will 
be based on MMRM imputed data. Time points other than Day 85 may also be explored. 
• CSF BIIB067 concentration at Day 85 vs ratio to baseline in CSF SOD1 at Day 85 
• CSF BIIB067 concentration at Day 85 vs ratio to baseline in CSF pNFH at Day 85 
• Plasma pNFH at Day 1 vs CSF pNFH at Day 1 
• Plasma pNFH at Day 85 vs CSF pNFH at Day 85  
 
 
 


 
 
 
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Completers to Day 169 
For subjects who completed the study to Day 169 and with data available at all visits through to 
Day 169, descriptive statistics of actual values and ratio to baseline will be presented by dose 
group for each PD biomarker. The summary statistics will include arithmetic mean and SD for 
the change from baseline as well as the geometric mean ratio and corresponding standard error. 
The geometric mean ratio will be obtained by back-transforming change from baseline on log 
transformed data. Arithmetic means and geometric means will be presented for the actual values 
at each visit. The descriptive summaries will be presented for all completers and by disease 
progression type. 
Plots of geometric means and geometric mean ratio to baseline with standard error bars will also 
be presented for all completers. These plots may also be presented by disease progression type. 
Observed data 
Descriptive statistics of actual values and ratio to baseline will be presented by dose group for 
each PD biomarker at all visits through to Day 169 for all patients. The descriptive summaries 
will be presented overall and by disease progression type. 
Spaghetti plots of actual values and ratio to baseline will be presented for each dose group to 
show individual subjects throughout all visits based on observed data to Day 169. Both the 
geometric mean and the median for the dose group will also be plotted on the spaghetti plots. 
Separate spaghetti plots of subjects who were fast progressors will also be presented. 
3.7 
Immunogenicity Data 
The immunogenicity population, as defined in Section 3.2.1, will be used for all analyses of 
immunogenicity data.  
• For immunogenicity, the baseline value is defined as the latest immunogenicity data 
collected at any time prior to the first dose.  If no immunogenicity data are collected prior 
to the first dose, the baseline value is missing and will be imputed as anti-drug antibody 
negative for immunogenicity analyses.  
• Subjects with at least one confirmed post-treatment positive result will be considered 
positive for anti-drug antibodies if their baseline result is negative. 
• Subjects where none of the post-treatment samples were positive for anti-drug antibodies 
will be considered negative regardless of their baseline result 
• For subjects that are confirmed positive at baseline and have at least one post-treatment 
sample with a ≥ 2-fold increase in titer will be considered positive for anti-drug 


 
 
 
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antibodies. Subjects that are positive at baseline, with subsequent post-treatment samples 
titers that are within 2-fold will be considered negative for anti-drug antibodies 
• Numbers and percentage of subjects who develop antibodies will be determined and 
summarized by dose groups and timepoint.  
 
The same summary will be provided for subjects with positive baseline results and for subjects 
with negative or missing baseline results, separately. 
3.8 
Clinical Function Data 
The clinical function set will be used for all analyses of clinical functions.  
Unless stated otherwise, baseline data are defined as the data collected prior to the time and/or on 
the date of first dose, which is usually the same day as the Day1/Baseline visit. If there is more 
than one value on/before the date of the first dose, the non-missing value closest to and prior to 
the first dose will be used as the baseline value. For 
 
 HHD and
 data were collected at Screening and not Day 1 so baseline values for 
endpoints on these assessments will be taken from the Screening visit. 
Any assessments of clinical functions at unscheduled visits will not be used in the analysis but 
will be listed. For some subjects in Cohort 5 of 233AS101 MAD study the 
 
 was not being collected until after the protocol was amended and 
approved (Version 2.0). Therefore, as these subjects in this cohort do not have a baseline 
, subjects in cohort 5 will not be included in the analysis models.  
These data will be listed and included under observed descriptive summaries. Similarly for 
ALSFRS-R Day 92, 
 HHD Day 22, these assessments were 
only collected after the protocol was amended and approved (Version 2.0) so were not collected 
for Cohort 5 subjects, so this timepoint cannot be used for analysis for Cohort 5 subjects. 
 
 
 
 
 
 
 
 
 


 
 
 
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For clinical function measurements, any post-baseline missing up to and including Day 85 or 
Day 92 will be imputed using 2 methods. Data beyond Day 85 (for 
 
SVC) or Day 92 (for ALSFRS-R, 
 HHD, 
) will not be imputed. 
 
 
Primary method of imputation: MMRM 
The MMRM model will be used to impute missing values and to obtain a complete dataset for 
actual values for each endpoint. The MMRM model for actual values will be used for the 
purpose of presenting descriptive statistics only. Missing values will be replaced by predicted 
values from the model. The model will include dose group, visit, treatment-by-visit interaction, 
baseline score and baseline score-by-visit interaction terms, and adjust for the following 
covariate: disease progression type. Visits to Day 85 (or Day 92) only will be included in the 
model.  
The MMRM model for change from baseline will be used to impute missing values as well as for 
inference, analyzing longitudinal assessment on change from baseline values up to Day 85 (or 
Day 92) for each endpoint. The model will include dose group, visit, treatment-by-visit 
interaction, baseline score, and baseline score-by-visit interaction terms, and adjust for the 
following covariate: disease progression type.  
For the MMRM model, an unstructured covariance (UN) matrix will be used to model the 
within-subject variability. Model convergence will be checked. If the unstructured covariance 
model fails to converge with the default Newton-Rhapson algorithm, the Fisher scoring 
algorithm will be used to provide initial values of the covariance parameters. In the event that 
none of the above methods yield convergence, a structured covariance such as the heterogeneous 
first-order autoregressive (ARH(1)) structure will be used. 
The MMRM models specified above for actual values and change from baseline to Day 85 (or 
Day 92) will also be applied on the subgroup analysis of disease progression type (other, fast). 
The model will be similar to that specified above for each subgroup level except disease 
progression type will not be included in the model. 
Predicted values that are outside of the range of a scale will be reset: eg if the predicted value is 
negative and the scale does not allow for a negative score then the value will be set to the 


 
 
 
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minimum possible score for that scale. Similarly if the predicted value is above the maximum 
possible score of the scale then the value will be set to the maximum possible score. 
Secondary method of imputation: LOCF 
As a sensitivity analysis the LOCF method will be used as a conservative estimate for some key 
endpoints. In the LOCF approach since baseline data will not be carried forward, if the first post-
baseline visit is missing, it will remain missing after applying LOCF imputation. LOCF will be 
applied on actual values at each visit to provide a complete dataset. 
The endpoints for clinical function data are given in Table 5 which also indicates whether 
imputation will be performed and which imputation methods.  
Table 5: Clinical function endpoints for Part B 
Clinical 
function  
Endpoint 
MMRM LOCF  
No imputed 
dataset 
ALSFRS-R 
- 
Total Score 
Y 
Y  
N 
- 
Functional domain 
scores (bulbar function, 
fine motor skills, gross 
motor skills, respiratory 
function) 
Y 
N 
N 
SVC 
- 
Percent predicted SVC 
Y 
Y 
N 


 
 
 
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HHD 
- 
HHD Megascore 
Y 
Y 
N 
- 
Muscle strength for each 
of 16 muscles 
- 
Proportion of subjects 
with zero muscle 
strengths 
N 
 
N 
N 
 
N 
Y 
 
Y 


 
 
 
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ALSFRS-R: single imputation analysis imputing score after death to a lower score  
For ALSFRS-R total score only, this imputation method will be determined for sensitivity 
analysis.  
- 
For those subjects who died determine what the last visit is; 
- 
Based on this visit number calculate the slope for all placebo patients with available data 
at this and Day 92 (using only the data at these 2 timepoints).  
- 
Of these placebo patients select the 50% with the worst slope (i.e. greatest decline). 
- 
From this 50% use the median slope to impute Day 92 observation for the patient who 
died. 
- 
Apply MMRM model as specified previously 
For example, subject A died with last visit with last ALSFRS-R assessment at Day 29. Then 
we can calculate slope from Day 29 to Day 92 (using only Day 29 and Day 92 data) for all 
placebo patients. We can, pick the median slope of the worst 50% placebo patients to linearly 
impute Day 92 (and only Day 92) observation for subject A. Then we can use MMRM to 
analyze the data. This is consistent with treating death as worst outcome. The MMRM model 
will be run overall and by disease progression type. 
  
 
 
 
Descriptive statistics to Day 85 (or Day 92) 
For each endpoint listed in Table 5, descriptive statistics of actual values and change from baseline 
at each visit will be summarized for continuous variables by dose group based on the imputed 
datasets as per Table 5 i.e. MMRM only, or MMRM and LOCF, 
 (LOCF after 
death).  The descriptive summaries will be presented overall and by disease progression type based 


 
 
 
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on both MMRM imputed data as well as LOCF imputed data. For ALSFRS-R total score the 
MMRM sensitivity model using single imputation after death will also be summarized. 
For those endpoints where MMRM or LOCF imputed datasets are not generated the later section 
on observed data will cover these.  
Plots of mean values and mean changes from baseline by visit will also be generated overall and 
by disease progression type for each clinical function based on MMRM imputed data (and LOCF 
data where applicable). These plots will also be presented for the MMRM sensitivity model 
using imputation after death for ALSFRS-R total score.    
Listings of individual data will also be provided. For individual questions/items within 
questionnaires, stacked bar charts may also be presented to show any shifts in responses. 
Statistical analysis 
Statistical analyses of clinical function endpoints will be performed for Part B with imputed data. 
When a placebo group is involved in an analysis, all subjects receiving placebo will be combined 
to form placebo control group.  The statistical analysis of clinical function endpoints will be 
performed for Part B only. All statistical tests will be conducted at the nominal significance level 
of 0.1. CIs will be constructed at the traditional 95% confidence level. No adjustment for 
multiple testing will be performed. Nominal p-values will be presented. 
As shown in Table 6 for the specified continuous clinical function endpoints, a 2-sample 
Wilcoxon rank sum test will be performed for change from baseline values at Day 85 (for 
ALSFRS-R, 
 SVC) or Day 92 (HHD, 
)  
each visit comparing each BIIB067 group vs. placebo group based on the MMRM imputed 
datasets. This will be the primary method of analysis based on the MMRM imputed dataset (as 
well as the sensitivity MMRM model with imputation after death for ALSFRS-R total score).  
These will be overall and by disease progression type.  
As sensitivity analysis the MMRM model for change from baseline will also be used for 
inference: For each clinical function endpoint as specified in Table 6 least-squares (LS) means of 
each dose level at each visit as well as treatment differences between each dose level vs. placebo 
at each visit will be presented, along with 95% CI and p-values. Results will be presented 
overall, and by disease progression type. The LSmean changes will also be plotted overall and by 
disease progression type. These will also be presented from the sensitivity MMRM model with 
imputation after death for ALSFRS-R total score. 
Similarly a MMRM model will be performed on the LOCF imputed dataset for those clinical  
function endpoints listed in Table 5. The model will be specified as detailed above for overall 
and by disease progression type. Results will be tabulated but not plotted. 


 
 
 
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Table 6: Clinical function endpoint statistical analysis for Part B 
Clinical 
function  
Endpoint 
Statistical 
Analysis 
Wilcoxon 
rank sum 
test at 
Day 85 
(or 92) 
LSMeans 
MMRM 
model 
LSMeans 
LOCF 
imputed 
MMRM 
model 
ALSFRS-R 
- 
Total Score 
Y 
Y 
Y 
Y  
- 
Functional domain 
scores (bulbar 
function, fine motor 
skills, gross motor 
skills, respiratory 
function) 
Y 
Y 
Y 
N 
SVC 
- 
Percent predicted SVC 
Y 
Y 
Y 
Y 


 
 
 
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HHD 
- 
HHD Megascore 
Y 
Y 
Y 
Y 
- 
Muscle strength for 
each of 16 muscles 
- 
Proportion of subjects 
with zero muscle 
strengths 
N 
N 
N 
N 
 
In addition, relationships between ALSFRS-R and PD biomarkers and selected clinical function 
endpoints will be examined using scatter plots, including the list below. The correlation 
coefficient (Spearman) will also be generated by dose group and for overall. The scatter plots 
and correlation coefficient tables will be repeated for disease progression type subgroups. These 


 
 
 
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will be based on MMRM imputed data. Time points other than Day 85 may also be explored. 
Visits may also be pooled through to Day 85 to look at the overall relationship. 
• Ratio to baseline in Plasma pNFH at Day 85 vs ALSFRS-R at Day 85 
• Ratio to baseline in Plasma pNFH at Day 85 vs change from baseline in ALSFRS-R to 
Day 85 
• Ratio to baseline in CSF pNFH at Day 85 vs ALSFRS-R at Day 85 
• Ratio to baseline in CSF pNFH at Day 85 vs change from baseline in ALSFRS-R to Day 
85 
• Ratio to baseline in CSF-SOD1 at Day 85 vs ALSFRS-R at Day 85 
• Ratio to baseline in CSF-SOD1 at Day 85 vs change from baseline in ALSFRS-R to Day 
85 
• 
 
• 
 
• EQ-5D utility index at each visit with ALSFRS-R total score 
• 
 with change from baseline in 
ALSFRS-R total score 
Further exploratory analyses may be performed looking at the relationship between the reduction 
in CSF-SOD1 or pNFH at selected timepoints with ALSFRS-R. Baseline characteristics and 
their relationship with ALSFRS-R may also be performed.   
Completers to Day 169 
For subjects who completed the study to Day 169 and with data available at all visits through to 
Day 169, descriptive statistics of actual values and changes from baseline will be presented by 
dose group for each continuous clinical function endpoint listed in Table 5. The descriptive 
summaries will be presented for all completers and by disease progression type. For the 
following non-continuous endpoints in Table 5, frequencies and percentages will be presented 
for each item/question/endpoint by visit: 
 
 
Plots of changes from baseline with standard error bars will also be presented for all completers. 
These plots may also be presented by disease progression type. 
Observed data 
Descriptive statistics of actual values and changes from baseline will be presented by dose group 
for each continuous clinical function endpoint listed in Table 5 at all visits through to Day 169 
for all patients. The descriptive summaries will be presented overall and by disease progression 


 
 
 
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type. For the following non-continuous endpoints in Table 5, frequencies and percentages will be 
presented for each item/question/endpoint by visit: 
 
 
Spaghetti plots of actual values and changes from baseline will be presented for each treatment 
group to show individual subjects throughout all visits based on observed data to Day 169. See 
Table 7. Separate spaghetti plots of subjects who were fast progressors will also be presented. 
The mutation subtype will also be indicated for each subject on the spaghetti plots. Listings of 
individual data on clinical functions will also be provided.  
Table 7: Clinical function endpoints with spaghetti plots 
Clinical 
function  
Endpoint 
Spaghetti plot 
ALSFRS-R 
- 
Total Score 
Y 
- 
Functional domain scores 
(bulbar function, fine motor 
skills, gross motor skills, 
respiratory function) 
N 
SVC 
- 
Percent predicted SVC 
Y 


 
 
 
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HHD 
- 
HHD Megascore 
Y 
- 
Muscle strength for each of 16 
muscles 
- 
Proportion of subjects with zero 
muscle strengths 
N 
 
Post-randomization slope in ALSFRS-R total score will be estimated by fitting a regression 
model on change from baseline over time (study day from Day 1 in months) for each subject’s 
rate of change. Two separate slopes will be estimated, one includes data from Day 1 and one 
includes data from on or after day 29. Data up to and including Day 92 will be included in the 
slope; data from Day 169 or any additional follow-up data from telephone calls for UK sites will 
not be included. Only observed data will be used to estimate the slopes. Descriptive statistics for 
the pre-randomization and both post-randomization slopes in ALSFRS-R total score will be 
summarized by dose group. A scatter plot of pre-randomization slope vs post-randomization 


 
 
 
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slope from Day 29 will be generated. The correlation coefficient (Spearman) will also be 
generated. The scatter plot will be repeated for disease progression type subgroups. 
To explore riluzole use in subjects, descriptive statistics for each of ALSFRS-R total score and 
percent predicted SVC will be presented by riluzole use (yes/no) for all subjects and also within 
each disease progression type. These will be based on observed data due to the small numbers of 
subjects and will be presented by visit from baseline through to Day 85. Similarly, descriptive 
statistics will also be presented for changes from baseline in ALSFRS-R total score and percent 
predicted SVC by visit to Day 85. 
4. Sample Size Justification 
The maximum sample size of 36 subjects for Part A of the study (SAD) is based on clinical 
rather than statistical considerations. Subjects will be randomized to receive BIIB067 or placebo 
in a 3:1 ratio in each cohort. Each cohort will have a minimum of 4 subjects (3 active and 1 
placebo), and a maximum of 12 subjects (9 active and 3 placebo). The final number for each 
cohort will be dependent on the DLT profile. If no DLT occurs in any dose level, then a total of 
20 subjects (15 active and 5 placebo) will be randomized. This design will allow for adequate 
evaluation of the safety of BIIB067, should DLT be encountered, as well as minimize subject 
exposure at subtherapeutic single doses. 
For Part B (MAD), up to 48 subjects will be enrolled in up to 4 cohorts, with up to 9 subjects 
randomized to receive BIIB067 and 3 subjects randomized to receive placebo for each cohort. 
This design will provide approximately 80% power to detect a difference in SOD1 reduction 
between 25% from the BIIB067 group and 12% from the placebo group at a 10% significance 
level. The sample size calculation assumes the same 10.5% SD in the 2 treatment groups. 
5. Changes to Planned Analyses 
The following analyses were specified in the protocol but not performed as they were not 
required. 
- 
For the summary of AEs by relationship, this was amended to a summary of related AEs 
by system organ class and preferred term 
- 
The percent change from baseline in clinical functions and PD parameters. The PD 
parameters were summarized using geometric means and geometric mean ratios in 
addition to arithmetic means. 
- 
A 2-sample student’s t-test to compare each dose of BIIB067 and placebo at a 2-sided 
alpha level of 0.1 for clinical functions and SOD1. Instead, a 2-sample Wilcoxon rank 
sum test and MMRM are used to analyze the clinical functions and PD parameters, as this 


 
 
 
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minimizes any undue influence of extreme values. Although 90% confidence intervals 
were presented for interim analyses, all confidence intervals will be 95% CI. The nature 
of the study and these endpoints were originally intended to be exploratory and so 90% 
confidence intervals were deemed as appropriate at the time. 
- 
Pharmacogenomic populations is not defined; the biomarker data is to be analyzed using 
PD population. 
- 
Biomarker NFL will be analysed as post-hoc due to availability of data.  
- 
Physical examination is collected under adverse events in case of any abnormalities and 
therefore there is no separate collection of these data and subsequently no separate 
analysis of these data. 
6. References 
 
 
 
 
 
 
 
 
 
Protocol 233AS101 Protocol V5.0  
 
 


 
 
 
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Appendix A: Derivation of C-SSRS 
The Columbia Suicide Severity Rating Scale (C-SSRS) is an assessment that evaluates suicidal 
ideation and behavior. C-SSRS measurements are collected with respect to “Lifetime: time 
he/she felt most suicidal” at baseline, and with respect to “Since last visit” at last visit (Day 57 
for Part A and Day 169 for Part B) and ET visit.   
There are 11 common “Yes/No” questions at baseline and post-baseline visits. Five questions on 
suicidal ideation and five questions on suicidal behavior are re-ordered and follow increasing 
severity order respectively as shown in Table A1. In particular, only patients who answered 
“Yes” to question 2 will proceed to question 3, 4 and 5. Thus, for any subjects who answered 
“No” to question 2, an answer “No” will also be assumed to question 3, 4, and 5. An additional 
“Yes/No” question is used to record if subject had committed suicide in post-baseline visits.  
Table A1: C-SSRS re-ordered questions 
Suicidal Ideation 
Question 1 
Wish to be dead 
Question 2 
Non-specific active suicidal thoughts 
Question 3 
Active suicidal ideation with any methods (not plan) 
without intent to act 
Question 4 
Active suicidal ideation with some intent to act, without 
specific plan 
Question 5 
Active suicidal ideation with specific plan and intent 
Suicidal Behavior 
Question 6 
 Preparatory acts or behavior 
Question 7 
Aborted attempt 
Question 8 
Interrupted attempt 
Question 9 
 Actual attempt  


 
 
 
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Question 10 
Suicidal behavior 
Question 11 (post-baseline visit 
only) 
Suicide 
Self-Injurious Behaviour without Suicidal Intent 
Question 12  
Self-injurious behavior without suicidal intent 
 
A subject is considered to have suicidal ideation at the period of interest if a “Yes” is answered 
to any of the five suicidal ideation questions (Question 1-5). A subject is considered to have 
suicidal behavior at the period of interest if a “Yes” is answered to any of the five suicidal 
behavior questions (Question 6-10) at baseline or a “Yes” is answered to any of the six suicidal 
behavior questions (Question 6-11) at post-baseline visit.  
A subject’s Suicidal Ideation Score is defined as the maximal suicidal ideation question number 
(maximal of 1-5) with an answer “Yes” per visit. The score is defined as 0 if the subject 
answered “No” to all 5 Suicidal Ideation questions at that visit. A subject is considered to have 
treatment-emergent suicidal ideation if the subject had either new or worsening suicidal ideation.  
A subject is considered to have new suicidal ideation if the subject’s Suicidal Ideation Score 
increased at post-baseline visit compared to a score 0 at baseline. A subject is considered to have 
worsening suicidal ideation if the subject’s Suicidal Ideation Score increased at post-baseline 
visit compared to a positive score at baseline. 
A subject is considered to have treatment-emergent suicidal behavior if the subject answered 
“Yes” to any suicidal behavior questions at any post-baseline visit while answered “No” to all 
suicidal behavior questions at baseline.  
 
 


 
 
 
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Appendix B: Derivation and Imputation of Clinical Function Endpoint 
ALSFRS-R 
The ALSFRS-R has been demonstrated to predict survival. The ALSFRS-R measures 4 
functional domains, comprising bulbar function (speech, salivation, swallowing), fine motor 
skills (handwriting, cutting food and handling utensils, dressing and hygiene), gross motor skills 
(turning in bed, walking, climbing stairs), and respiratory function (dyspnea, orthopnea, 
respiratory insufficiency). Each domain consists of 3 items, each scored from 0 to 4 with higher 
scores representing better function. Therefore, the total possible score for ALSFRS-R is 48. 
The ALSFRS-R total score will be considered missing if more than 3 individual item scores are 
missing. If no more than 3 (≤ 3) individual item scores are missing and each functional domain 
has at least one individual item score available, the functional domain score with any missing 
item score(s) will be calculated by the following formula:  
ALSFRS-R domain score = [(average of all answered item scores) x 3]. 
The ALSFRS-R total score is the sum of the 4 functional domain scores. If 3 individual item 
scores are missing from the same functional domain, then the ALSFRS-R domain score is 
considered as missing and the total score is calculated by the following formula:   
ALSFRS-R total score = average of all answered item scores from other 3 domains x 12.  
Percent Predicted SVC 
Vital capacity will be measured by means of an SVC test, administered in the upright position. 
Upright SVC will be determined by performing 3 to 5 measures, in accordance with criteria 
established by the American Thoracic Society and the European Respiratory Society. The 
maximum of the percent predicted upright SVC values at each visit will be used for the analysis. 
The percent predicted SVC will be calculated as [observed SVC divided by predicted SVC] x 
100%. The predicted SVC is adjusted by sex, age, height, which is programmed into and 
performed by the equipment used.  
 
 
 
 
  
 
 
 


 
 
 
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HHD  
Sixteen muscle groups (left and right shoulder flexion, left and right elbow flexion, left and right 
wrist extension, left and right abduction index finger, left and right abduction thumb, left and 
right abduction 5th digit, left and right knee extension, and left and right ankle dorsiflexion) will 


 
 
 
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be examined in both upper and lower extremities. At each visit, each muscle will be collected as 
Best Trial 1 and Best Trial 2 and the maximum value of the measures will be used for the 
analysis. 
Any missing muscle strength with a reason of ‘UNABLE TO TEST’ will be imputed as 0 for 
analysis.  
Megascore 
Mean and standard deviation (SD) for each muscle group will be established from the baseline 
values of all patients in this trial. For the purpose of calculating megascore, the mean and SD of 
the baseline value will be used across all patients regardless of dose/treatment group. The muscle 
strength values will be normalized to Z scores as (post-baseline measurements – mean)/SD and 
averaged to provide HHD overall megascore. The overall megascore is created by averaging all 
eight bilateral measurement Z scores, if no more than 10 (≤ 10) measures are missing. The 
overall megascore will be considered missing if more than 10 measures are missing out of 16 
total measures.  
HHD zero strength (for Part B) 
The zero strength will be derived based on the combined muscle group of 4 selected muscle 
pairs: first dorsal interosseous left/right, elbow flexion left/right, knee extension left/right, ankle 
dorsiflexion left/right. The zero strength is defined as: an observed zero strength on HHD on any 
1 of the 4 selected muscle pairs that is not zero or missing at baseline or has at least one positive 
postbaseline strength before that observed zero, for which the observed zero strength is 
subsequently confirmed at the next available measurement, where the confirmation can be in the 
form of an observed zero strength or patient death. The time to zero strength may be derived. 
The time to zero strength is defined as the time since randomization to the time of the first 
observed zero that is subsequently confirmed (note: time to the first observed zero; not time to 
confirmation).  The unit of time to zero strength will be in months. If a patient does not 
experience a zero strength, withdraws or is lost to follow-up during the study, the patient’s time 
to zero strength in the study will be marked as right-censored. Time-to-zero strength will be also 
derived for each of the 16 individual muscles.  
 
 
 
 
 
 


 
 
 
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DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
Statistical Analysis Plan – Study 233AS101 Part C 
Final Version No.: 2.0, 14 August 2021 
Study Title: A Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of BIIB067 Administered to Adult Subjects with Amyotrophic Lateral 
Sclerosis and Confirmed Superoxide Dismutase 1 Mutation 
Name of Study Treatment: Tofersen (BIIB067) 
Protocol No.: 233AS101/ NCT02623699
Study Phase: 1/2/3 
Confidential Information 
The information contained in this Statistical Analysis Plan (SAP) is confidential and may not 
be reproduced or otherwise disseminated without the approval of Biogen, Inc. 




DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
VERSION HISTORY 
 
 
SAP Version 
Date 
Primary Reasons for Amendment 
1.0 
09June2021 
Final version 
2.0 
14Aug2021 
Amended primary efficacy analysis for ALSFRS-R 
and primary analysis for percent predicted SVC and 
included rationale in changes to planned analyses; 
additional analyses added for ALSFRS based on FDA 
feedback; included tipping point analysis as sensitivity 
analysis for ALSFRS-R; updated AE of note table; 
added listing of site transfers; listed samples 
unavailable for analysis; added 
sensitivity/supplementary analyses for ALFSRS; 
addition of covariate for SVC; clarifications on 
sensitivity analyses for ALSFRS; clarification on 
ventilation data; sensitivity analysis for time to death 
or permanent ventilation added; clarification on 
subgroup analyses; indicated CSF NfL may not be 
available at time of DBL; amended SMQ for 
immunogenicity analysis; 
made minor clarifications/corrections 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
TABLE OF CONTENTS 
VERSION HISTORY ..................................................................................................................... 3 
1. 
Introduction ........................................................................................................................... 11 
1.1 
Primary objective and endpoints ............................................................................... 11 
1.2 
Secondary objectives and endpoints .......................................................................... 12 
 
 13 
2. 
Study Design and Conduct .................................................................................................... 14 
2.1 
Study Description ...................................................................................................... 14 
2.2 
General Trial Conduct Mitigation Strategy under COVID-19 Pandemic ................. 16 
2.3 
Detail of Assessments Not Collected According to Protocol .................................... 18 
3. 
Sample Size Justification ...................................................................................................... 27 
4. 
General Considerations ......................................................................................................... 27 
4.1 
Statistical Methods: General Considerations ............................................................. 27 
4.2 
Analysis Populations ................................................................................................. 28 
4.3 
Visit Windows for Early Withdrawal, Unscheduled Visits and Early Termination 
Visits in the Event of Early Study Closure ............................................................................... 31 
5. 
Study Subjects ....................................................................................................................... 34 
5.1 
Subject Accountability ............................................................................................... 34 
5.2 
Demography and Baseline Disease Characteristics ................................................... 35 
5.3 
Extent of Exposure and Study Drug Compliance ...................................................... 37 
5.4 
Concomitant Medications and Non-Drug Treatments/Procedures ............................ 40 
5.5 
Protocol Deviations and Compliance ........................................................................ 42 
5.6 
Protocol Alternations ................................................................................................. 44 
6. 
Efficacy Data......................................................................................................................... 44 
6.1 
General Considerations .............................................................................................. 44 
6.2 
Primary Efficacy Endpoint ........................................................................................ 64 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
6.2.1 
Primary analysis ....................................................................................................... 64 
6.2.2 
Sensitivity analysis of primary endpoint .................................................................. 65 
6.2.3 
Secondary analysis of primary endpoint .................................................................. 69 
6.2.4 
Supplementary analysis of primary endpoint ........................................................... 71 
6.2.5 
Additional analysis of primary endpoint .................................................................. 80 
6.3 
Secondary Efficacy Endpoints ................................................................................... 81 
6.3.1. Percent predicted SVC ............................................................................................. 81 
6.3.1.1. Primary analysis of percent predicted SVC ............................................................. 81 
6.3.1.2. Sensitivity and secondary analysis of percent predicted SVC ................................. 81 
6.3.2. HHD ......................................................................................................................... 82 
6.3.2.1. Primary analysis of HHD megascore ....................................................................... 82 
6.3.2.2. Sensitivity and secondary analysis of HHD megascore ........................................... 82 
6.3.2.3. Supplementary analysis of HHD .............................................................................. 83 
6.3.3. Time to death or permanent ventilation ................................................................... 83 
6.3.3.1. Primary analysis of time to death or permanent ventilation ..................................... 83 
6.3.3.2. Sensitivity and secondary analysis of time to death or permanent ventilation......... 86 
6.3.3.3. Supplementary analysis of time to death or mechanical ventilation ........................ 86 
6.3.4. Time to death ............................................................................................................ 88 
6.3.4.1. Primary analysis of time to death ............................................................................. 88 
6.3.4.2. Sensitivity and secondary analysis of time to death ................................................. 88 
 
 88 
6.5 
Subgroup Analysis ..................................................................................................... 92 
6.6 
Statistical Testing Procedure ..................................................................................... 94 
 
 96 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
8. 
Pharmacodynamic Data ........................................................................................................ 97 
9. 
Safety Data .......................................................................................................................... 100 
9.1 
Adverse Events ........................................................................................................ 100 
9.2 
Laboratory Data ....................................................................................................... 104 
9.3 
Vital Signs ............................................................................................................... 106 
9.4 
ECG ......................................................................................................................... 107 
9.5 
Mini-Mental State Exam (MMSE) .......................................................................... 107 
9.6 
Limited neurological examinations ......................................................................... 107 
9.7 
Columbia Suicide Severity Rating Scale (C-SSRS) ................................................ 108 
9.8 
Interim Safety Analyses ........................................................................................... 108 
 109 
11. Changes to Planned Analyses ............................................................................................. 111 
12. Summary of Changes from the Previous Version of the SAP ............................................ 112 
13. References ........................................................................................................................... 114 
Appendix A: Derivation of Demographic and Baseline Characteristics .................................... 116 
Appendix B: Derivation and Imputation of Clinical Function Endpoint .................................... 117 
 131 
Appendix D: Derivation of C-SSRS ........................................................................................... 133 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
List of Abbreviations 
 
Ab 
antibodies 
ADM 
abductor digit minimi 
AE 
adverse event 
ALS 
amyotrophic lateral sclerosis 
ALSFRS-R 
ALS Functional Rating Scale (revised) 
ALT 
alanine aminotransferase 
ANCOVA 
analysis of covariance 
APB 
abductor pollicis brevis 
aPTT 
activated partial thromboplastin time 
AST 
aspartate aminotransferase 
AUC 
area under the curve 
BB 
bicep 
BLQ 
below limit quantitation 
BMI 
body mass index 
bpm 
beats per minute 
BUN 
blood urea nitrogen 
CDISC 
Clinical Data Interchange Standards Consortium 
CI 
confidence interval 
Cmax 
maximum concentration 
CO2 
bicarbonate 
COVID-19 
Coronavirus Disease 2019 
CRF 
case report form 
CSF 
Cerebral-spinal fluid 
C-SSRS 
Columbia suicide severity rating scale 
CTCAE 
common terminology criteria for adverse events 
DNA 
deoxyribonucleic acid 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
EAC 
Event Adjudication Committee 
EAIR 
exposure adjusted incidence rates 
ECG 
electrocardiogram 
EDB 
extensor digitorum 
EOS 
end of study (visit) 
ET 
early termination (visit) 
FDIO 
first dorsal interosseous 
FSH 
follicle-stimulating hormone 
FU 
follow-up 
FWER 
family-wise error rate 
GGT 
gamma-glutamyl transferase 
GGW 
generalized Gehan-Wilcoxon 
GH 
general health 
HBV 
Hepatitis B Virus 
HCV 
Hepatitis C Virus 
HHD 
hand-held dynamometry 
HIV 
human immunodeficiency virus 
ICC 
intraclass correlation 
ICH 
International Council for Harmonisation 
IDMC 
independent data monitoring committee 
INR 
international normalized ratio 
IRT 
interactive randomization system 
ITT 
intent-to-treat 
LLOQ 
lower limit of quantitation 
LP 
lumbar puncture 
LOCF 
last observation carried forward 
LS 
least square 
LTE 
long term extension 
MAD 
multiple-ascending dose 
MCMC 
Markov Chain Monte Carlo 
MedDRA 
Medical Dictionary for Regulatory Activities 
mg 
milligram 
MH 
mental health 
MI 
multiple imputation 
MITOS 
Milano-Torino Staging 
mITT 
modified intent to treat 
mmHg 
millimeters of mercury 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
MMRM 
mixed model for repeated measures 
MMSE 
mini-mental state exam 
N 
number of subjects or observations 
NfH 
neurofilament heavy chain 
NfL 
neurofilament light chain 
ng/mL 
nanogram/milliliter 
PAV 
permanent assisted ventilation 
PD 
pharmacodynamics 
PF 
physical functioning 
pg/mL 
picogram/milliliter 
PK 
pharmacokinetic(s) 
PRO 
patient reported outcome 
PT 
prothrombin time 
QTc 
interval between the start of the QRS complex and the end of the 
T wave, corrected for heart rate 
QTcF 
QTc interval using Fridericia’s formula 
RBC 
red blood cell (count) 
RE 
role emotional 
RNA 
ribonucleic acid 
RP 
role physical 
RR 
inter-beat 
TA 
tibialis anterior 
Tmax 
time to maximum concentration 
SAD 
single-ascending dose 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SAS 
statistical analysis system 
SD 
standard deviation 
SDTM 
standard data tabulation model 
SE 
standard error 
SF 
social functioning 
SOC 
system organ class 
SOD1 
superoxide dismutase 1 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
 
 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
SVC 
slow vital capacity 
ULN 
upper limit of normal 
UN 
unstructured 
VT 
vitality 
WBC 
white blood cell (count) 
WHO 
World Health Organization 


DocuSign Envelope ID: D3376B93-F38F-4AA6-9209-9BB32BCD9083 
CONFIDENTIAL 
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc. 
11 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
1. Introduction 
 
Study 233AS101 is a randomized, double-blind, placebo-controlled, 3-part study to examine the 
efficacy, safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of BIIB067, 
administered by intrathecal bolus injection in subjects with ALS and a confirmed SOD1 
mutation. 
BIIB067 will be referred to as tofersen throughout the rest of the statistical analysis plan. 
Parts A and B are single-ascending dose (SAD) and multiple-ascending dose (MAD) 
components, respectively, in which subjects will be randomized to receive tofersen or placebo in 
a 3:1 (active:placebo) ratio. In Part C, approximately 99 subjects will be randomized to receive 
tofersen 100 mg or placebo in a 2:1 (active:placebo) ratio. This statistical analysis plan (SAP) is 
prepared for the clinical study report(s) for Part C; a separate SAP exists for Parts A and B. 
Subjects have the option of enrolling into a long-term extension study (233AS102) on 
completion of Study 233AS101. Separate SAPs will be prepared for the analyses of 233AS102 
and integrated analyses across the studies. A separate SAP will also detail analyses for defining 
clinical meaningfulness on Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised 
(ALSFRS-R). 
Blinded safety data will be reviewed on an ongoing basis by the Sponsor and the Medical 
Monitor. Unblinded safety data will be reviewed on an ongoing basis by an Independent Data 
Monitoring Committee (IDMC). 
 
This SAP also covers how the impact of the Coronavirus Disease 2019 (COVID-19) pandemic 
will be handled. 
 
1.1 Primary objective and endpoints 
 
The primary objective of Part C of this study is to evaluate the clinical efficacy of tofersen 
administered to adult subjects with ALS and a confirmed SOD1 mutation. 
The primary efficacy endpoint is the change from baseline to Week 28 (Day 197) in the 
ALSFRS-R total score. 


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12 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
The secondary efficacy endpoints are as follows: 
 
• Change from baseline to Week 28 (Day 197) in slow vital capacity (SVC). 
• Change from baseline to Week 28 (Day 197) in handheld dynamometry (HHD) 
megascore to assess muscle strength, as measured by the HHD device. 
• Time to death or permanent assisted ventilation, defined as the time to the earliest 
occurrence of one of the following events: 
− Death. 
− Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or 
noninvasive] per day for ≥ 21 consecutive days). 
This endpoint will be adjudicated by a blinded, independent group of experienced 
clinicians, the Event Adjudication Committee (EAC), based on review of clinical 
study data and supporting information. 
• Time to death. 
 
 
 
 
 
1.2 Secondary objectives and endpoints 
 
The secondary objectives of Part C are to evaluate the safety, tolerability, pharmacodynamic 
(PD) and biomarker effects of tofersen administered to adult subjects with ALS and a confirmed 
SOD1 mutation. 
 
• The safety/tolerability endpoint is the incidence of AEs and SAEs. 
• The PD endpoint is the change (i.e. ratio) from baseline in total SOD1 
concentration in cerebral-spinal fluid (CSF). 
• The biomarker endpoint is the change (i.e. ratio) from baseline in neurofilament 
light chain (NfL) concentration in plasma. 
• Other safety endpoints are changes and shifts in abnormalities for: 
o clinical laboratory tests (serum chemistry, haematology, urinalysis, CSF 
laboratory parameters and coagulation) 
o Electrocardiogram (ECG) 
o Vital signs 
o Weight 






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15 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
Subjects included in the study must have weakness attributable to ALS and a confirmed SOD1 
mutation. 
i. 
SOD1 mutation must be confirmed by the central reader based on the sample 
obtained during the Screening Visit; subjects with a SOD1 mutation interpreted 
by the central reader to be pathogenic or likely pathogenic will be eligible. 
ii. 
Additionally: 
• Prognostic enrichment criteria for rapid disease progression (subjects may be eligible 
based on 1 of the following 2 criteria) [Hamidou 2017; Proudfoot 2016] 
a. One of the following SOD1 mutations and a prerandomization ALSFRS-R 
decline slope ≥ 0.2 per month (calculated as [48-baseline score]/time since 
symptom onset): 
p.Ala5Val, p.Ala5Thr, p.Leu39Val, p.Gly42Ser, p.His44Arg, 
p.Leu85Val, p.Gly94Ala, p.Leu107Val, and p.Val149Gly 
OR 
b. SOD1 mutation other than those listed in item ‘a.’ with prerandomization 
ALSFRS-R decline slope ≥ 0.9 per month (calculated as [48-baseline 
score]/time since symptom onset) 
• Criteria for all other eligible subjects: SOD1 mutation other than those listed in item 
‘a.’ (no ALSFRS-R decline slope requirement). These are subjects who have a 
pathogenic or likely pathogenic SOD1 mutation not listed in ‘a’ with a 
prerandomization ALSFRS-R decline slope < 0.9 per month. 
Note: subjects with a SOD1 mutation listed in item ‘a’ who have a prerandomization 
decline slope <0.2 per month are not included in the study. 
For participants who meet prognostic enrichment criteria for rapid disease progression, SVC 
≥ 65% of predicted value at screening as adjusted for sex, age, and height (from the sitting 
position). For all other eligible subjects must have SVC ≥ 50% of predicted value as adjusted for 
sex, age, and height (from the sitting position). 
Randomization will be stratified by the following 3 factors: 
• whether a subject meets the prognostic enrichment criteria for rapid disease 
progression; 
• whether a subject uses edaravone at baseline; 
• whether a subject uses riluzole (but not edaravone) at baseline. 
− Use of both edaravone and riluzole will not be a separate stratum but will be 
classified as edaravone use. 


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16 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
For subjects participating in Part C (Pivotal), the study duration will be approximately 32 to 
36 weeks in duration including a 4-week screening period, a 24-week treatment period (3 loading 
doses of tofersen or placebo 2 weeks apart, followed by 5 maintenance doses of tofersen or 
placebo 4 weeks apart), and a 4 to 8 week follow-up period as follows: 
Part C subjects who enroll (uninterrupted) in the long term extension study 233AS102 Week 
28/Day 197 Visit will serve as EOS. 
After completing the EOS visit, subjects will be considered study completers and they will have 
the option to participate in 233AS102, if eligible. This will be done without unblinding to 
subject’s treatment group. 
For subjects with delays between their Week 28/Day 197 Visit and enrollment in 233AS102 
study, a Safety FU (Alternative EOS) Visit will be conducted (either in person or by telephone 
contact) to collect AEs, SAEs, and concomitant medications or procedures. This Safety FU 
(Alternative EOS) Visit can be performed at Week 32 or prior to (within 2 days) enrollment in 
233AS102, whichever comes first. 
 
For Part C subjects who do not enroll in 233AS102, Week 32/Day 225 will serve as the EOS 
(either in person or by telephone contact) to collect AEs, SAEs, and concomitant medications or 
procedures. 
End of study date is the last visit or contact with the subject. 
In the event of a decision by the Study Sponsor to terminate the study earlier on the grounds that 
conducting a placebo-controlled study is no longer deemed ethical based on the assessment of 
risk-benefit of Study 233AS101, all subjects will be invited for an EOS visit, during which all 
Week 28/Day 197 assessments will be conducted. These subjects not entering 233AS102 will 
have an additional safety follow-up visit 8 weeks after the last dose of study treatment. 
Subjects who discontinue study treatment in Part C will be encouraged to remain in the study and 
complete all appropriate protocol-specified tests and assessments. It is recommended that 
subjects who terminate early (i.e., discontinue both study treatment and study assessments) 
perform the assessments of the Week 28/Day 197 End of Study (EOS) visit within 4 weeks after 
the last dose of study treatment. Home assessments will be allowed at the discretion of the 
Investigator for subjects who cannot come to the site in person for their Early Termination Visit. 
2.2 General Trial Conduct Mitigation Strategy under COVID-19 Pandemic 
In order to mitigate risk of missing dosing or assessments during the time of the COVID-19 
pandemic, the following has been put into place: 
• If a site is not closed due to COVID-19 and the site enables the subject to attend the visit 
in-clinic, then delayed visits within a reasonable timeframe are allowed. In the analysis, 
for the loading dose period, a 7-day window will be used and a 14-day window will be 
used for the maintenance visits. 


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17 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
• Site transfers are encouraged where possible, so that subjects can be transferred to 
another site for assessment. Instructions are in place to enable sites to do this including 
transfer of the database and source documents for the patient from the transferring site to 
the receiving site. This will be the optimal option in order to perform dosing and all 
assessments for the subject, since dosing can only be performed in the clinic setting due 
to intrathecal administration. In particular, if screening cannot be performed in the clinic, 
subjects will be screened at a screening site and subsequently transferred to another site. 
Site transfer instructions and travel plans were already in place prior to COVID-19 
pandemic to allow for subjects to travel to sites if a site was not open in their country of 
residence. 
• If site transfers cannot be performed, subjects will be allowed to have home visits if 
agreed to by the participating site. Instructions are in place on how this will work. If a 
home visit is performed, ALSFRS-R will still be performed by the blinded rater at the site 
via telephone. Due to the nature of the ALSFRS-R, as a status assessment, the informed 
consent allows for telephone visits to collect safety data. It has been shown that there is a 
strong correlation (r2=0.941, P < 0.05) between ALSFRS-R administered to patients in 
the clinic and by telephone (Mannino, 2006). Ventilation diaries recorded on paper will 
be collected by the staff performing home visits and provided directly to the sites. 
• Currently if home visits are not possible or not yet set up for the participating site, a 
phone visit can be used to collect safety data (AEs, SAEs, C-SSRS, concomitant 
medications/procedures) and ALSFRS-R. 
• Patient reported outcomes were not allowed to be collected by telemedicine based on the 
original informed consent. An addendum to the global informed consent will allow these 
assessments to be collected over the telephone after the date it is effective. 
• Due to regulations at sites, some sites may allow a clinic visit but not allow SVC to be 
performed in which case it is preferable to perform this assessment as a home visit or 
transfer the patient to another site. 
• Transferring sites are encouraged to enter and clean all data before transferring the 
subject to the receiving site. The database for a subject will remain with the transferring 
site until data are entered and cleaned as much as possible, but the transferring site must 
have access to the subject in IRT and copies of all source documents. Blinding of staff 
will be maintained as appropriate. Any queries raised later on for data belonging to visits 
at the transferring site will be cleaned by the receiving site through the source documents, 
and interaction between monitors at the receiving and transferring sites. The transferring 
site will no longer have access to the database for a subject they have transferred but the 
monitors will. The Subject ID will remain the same when a subject is transferred to 
another site, but the transfer can be tracked via the Site ID. 


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18 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
2.3 Detail of Assessments Not Collected According to Protocol 
 
In order to handle data appropriately for analysis, the method of collection for assessments is 
also being collected in the database. Table 1 shows the schedule of assessments. There are some 
points to note around differences in data collection between protocol amendments for 233AS101 
Part C. 
 
• The protocol specified that the same qualified and trained ALSFRS-R rater should 
consistently perform the ALSFRS-R for a subject. Protocol Version 6 allowed for a 
trained and qualified back-up rater to perform the ALSFRS-R in case the primary rater 
was not available. The raters should remain blinded to subjects’ treatment assignments 
and to the results of other assessments. Having a back-up rater is also important in light 
of the COVID-19 pandemic where it may not be possible to keep the same rater 
throughout. In an inter-rater reliability assessment (Kaufman, 2007), the primary raters 
performed 54 ratings on 9 patients showing ICC = 0.93 (95% CI 0.84–0.98). For back‐ 
up raters, 32 ratings on nine patients resulted in ICC = 0.93 (95% CI 0.82–0.98). The 
intra‐ rater reliability for in‐ person interviews was ICC = 0.95 (95% CI 0.92–0.98). The 
reliability of telephone administration compared to in‐ person interviews was ICC = 0.97 
(95% CI 0.93–0.98). 
• 
 
 
• In addition MMSE was initially collected at the same time as Neurological Examination 
but in Protocol Version 6 the frequency of the MMSE was reduced to every 3 months 
during the treatment period of Part C, as there had been no significant safety findings on 
this assessment seen in Part B of the study. Therefore, some subjects will have MMSE 
collected pre- and postdose at all postbaseline visits while some subjects will only have 
MMSE collected at Days 85, 169 and 197 during the treatment period. 
• 
 
. 
• 
 
• At Day 197, blood samples of 
, and anti-BIIB067 Ab as well as CSF samples 
were intended to be collected as part of baseline for 233AS102. However, they were 
inadvertently omitted from the schedule of activities at Day 197 of 233AS101 Part C. 
Also, for subjects who do not enter 233AS102, blood samples would need to be collected 


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19 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
at Day 197. There may be a few patients who do not have the plasma or CSF samples 
available at Day 197. In particular, for subjects who cannot attend a clinic visit due to 
COVID-19 or subjects who do not enter 233AS102 they may not have these samples 
collected (blood samples can be collected at home visits, if a home visit is possible). CSF 
sampling is associated with a lumbar puncture and is generally only performed as part of 
study drug administration therefore some subjects are unlikely to have CSF samples 
available at Day 197. 
• ECG was intended to be collected postdose as well as predose but this was inadvertently 
omitted from the schedule of activities until Protocol Version 6. In addition, there was a 
misinterpretation of which dosing days ECG should be collected at and was being 
collected at all dosing visits, although it should only have been collected at dosing Days 
85 and 169. This was clarified under Protocol Version 7. Some subjects therefore also 
have additional ECG data at Days 15, 29, 57, 113 and 141. 
 
As a general note, Day 197 should serve as the same visit as Baseline in 233AS102 for the 
majority of subjects. The data should be entered under the 233AS101 Part C database but 
there may be a few exceptions where the incorrect lab kit was used from 233AS102 and so 
the data are entered under Baseline in 233AS102. In that situation where Day 197 for 
233AS101 Part C and Baseline for 233AS102 are the same visit, the data will be taken from 
the 233AS102 database and incorporated into the datasets at the CDISC SDTM level. There 
is also the scenario where Baseline for 233AS102 did not occur at Day 197 of 233AS101 
Part C but a Day 197 lab kit was used for baseline. Therefore, in that scenario, the baseline 
data will be taken from Day 197 of 233AS101; it will be clear from date of sample collection 
as to which visit these data are associated with. This will be handled at the SDTM level. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Table 1: 
Schedule of Activities: Part C (Pivotal) 
 
Screening1 
Loading Dose Treatment Period 
Maintenance 
Treatment Period 
EOS Visit2,3 
Safety FU 
(Alternative EOS) 
Visit 4 
(In Person or 
Telephone Contact) 
Baseline 
(Dose 1) 
Week 2 
(Dose 2) 
Week 4 
(Dose 3) 
Week 8, 12, 16, 20, 
and 24 
Week 28 OR 
(4 Weeks 
After Last 
Dose) 
Week 32 OR 
(8 Weeks After Last 
Dose) 
Tests and Assessments5 
Day 
-28 to 
Day -1 
Day 1 
(±3 days) 
Day 15 
(±3 days) 
Day 29 
(±3 days) 
Days 57, 85, 113, 
141, and 169 
(±3 days) 
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days) 
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days) 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Informed Consent 
(main)6 
X 
Medical History 
X 
Confirmation of 
Eligibility Criteria 
X 
X 
Randomization 
X 
Telephone Contact7 
X 
X 
X 
X 
Ventilation Use8, 9 
X 
X 
X 
X 
X 
ALSFRS-R8 
X 
X 
X 
X 
X 
X 
SVC8,10 
X 
X 
X 
X 
X 
X 


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21 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Screening1 
Loading Dose Treatment Period 
Maintenance 
Treatment Period 
EOS Visit2,3 
Safety FU 
(Alternative EOS) 
Visit 4 
(In Person or 
Telephone Contact) 
Baseline 
(Dose 1) 
Week 2 
(Dose 2) 
Week 4 
(Dose 3) 
Week 8, 12, 16, 20, 
and 24 
Week 28 OR 
(4 Weeks 
After Last 
Dose) 
Week 32 OR 
(8 Weeks After Last 
Dose) 
Tests and Assessments5 
Day 
-28 to 
Day -1 
Day 1 
(±3 days) 
Day 15 
(±3 days) 
Day 29 
(±3 days) 
Days 57, 85, 113, 
141, and 169 
(±3 days) 
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days) 
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days) 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
HHD8 
X 
X 
X 
X 
X 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Screening1 
Loading Dose Treatment Period 
Maintenance 
Treatment Period 
EOS Visit2,3 
Safety FU 
(Alternative EOS) 
Visit 4 
(In Person or 
Telephone Contact) 
Baseline 
(Dose 1) 
Week 2 
(Dose 2) 
Week 4 
(Dose 3) 
Week 8, 12, 16, 20, 
and 24 
Week 28 OR 
(4 Weeks 
After Last 
Dose) 
Week 32 OR 
(8 Weeks After Last 
Dose) 
Tests and Assessments5 
Day 
-28 to 
Day -1 
Day 1 
(±3 days) 
Day 15 
(±3 days) 
Day 29 
(±3 days) 
Days 57, 85, 113, 
141, and 169 
(±3 days) 
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days) 
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days) 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
C-SSRS Questionnaire8 
X 
X13 
X13 
X13 
Height 
X 
Weight14 
X 
X 
X 
X 
Vital Signs 
(temperature, blood 
pressure, pulse rate, 
respiratory rate)14,15 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
12-Lead ECG14,16 
X 
X 
X17 
X11 
X17 
X 
Physical Examination14 
X 
X 
X18 
X18 
X18 
X18 
Limited Neurological 
Examination14,19 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
MMSE 
X 
X 
X 
X11 
X11 
X 
FSH Test20 
X 
Pregnancy Test14,21,22 
X (serum) 
X 
X 
X 
X 
X (serum) 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Screening1 
Loading Dose Treatment Period 
Maintenance 
Treatment Period 
EOS Visit2,3 
Safety FU 
(Alternative EOS) 
Visit 4 
(In Person or 
Telephone Contact) 
Baseline 
(Dose 1) 
Week 2 
(Dose 2) 
Week 4 
(Dose 3) 
Week 8, 12, 16, 20, 
and 24 
Week 28 OR 
(4 Weeks 
After Last 
Dose) 
Week 32 OR 
(8 Weeks After Last 
Dose) 
Tests and Assessments5 
Day 
-28 to 
Day -1 
Day 1 
(±3 days) 
Day 15 
(±3 days) 
Day 29 
(±3 days) 
Days 57, 85, 113, 
141, and 169 
(±3 days) 
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days) 
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days) 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
CSF Sampling for 
, 
PD, Safety, and 
Biomarkers14,23,24 
X 
X 
X 
X 
X 
Blood Sampling for 
HIV, HCV, and HBV 
Testing 
X 
Clinical Laboratory 
Samples for 
Hematology, 
Coagulation, Chemistry, 
and Urinalysis8,23 
X 
X 
X 
X 
X 
X 


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24 
 
 
 
Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Screening1 
Loading Dose Treatment Period 
Maintenance 
Treatment Period 
EOS Visit2,3 
Safety FU 
(Alternative EOS) 
Visit 4 
(In Person or 
Telephone Contact) 
Baseline 
(Dose 1) 
Week 2 
(Dose 2) 
Week 4 
(Dose 3) 
Week 8, 12, 16, 20, 
and 24 
Week 28 OR 
(4 Weeks 
After Last 
Dose) 
Week 32 OR 
(8 Weeks After Last 
Dose) 
Tests and Assessments5 
Day 
-28 to 
Day -1 
Day 1 
(±3 days) 
Day 15 
(±3 days) 
Day 29 
(±3 days) 
Days 57, 85, 113, 
141, and 169 
(±3 days) 
Day 197 OR 4 
Weeks After 
Last Dose 
(±3 days) 
Day 225 OR 8 Weeks 
After Last Dose 
(±3 days) 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Pre 
dose 
LP 
Post 
dose 
Blood Samples for 
anti-BIIB067 Ab8 
X 
X 
X 
X 
X 
Blood Sampling for 
Biomarkers8 
X 
X 
X 
X 
X 
Study Drug 
Administration28 
X 
X 
X 
X 
AE and Concomitant 
Therapy and Procedures 
Recording 
X (ongoing) 
SAE Recording 
X (ongoing) 






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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
3. Sample Size Justification 
For Part C, approximately 99 subjects will be randomized, with approximately 66 subjects 
administered tofersen 100 mg and approximately 33 subjects administered placebo in a 2:1 ratio. 
This sample size for Part C is selected primarily based on the joint rank test combining the 
Week 28 change from baseline in ALSFRS-R and mortality, in the mITT population 
(N = 60). The observed results from an interim analysis of Study 233AS101 in the fast 
progressor group as well as the observed ALSFRS-R decline in subjects who received placebo in 
a similar fast progressor ALS population with SOD1 mutation [Benatar 2018] are the basis of 
assumed treatment effect and the variability. Subjects from both datasets were matched with the 
prognostic enrichment criteria for rapid disease progression specified in this protocol for Part C 
(i.e., one of the protocol-defined SOD1 mutations and a pre-randomization ALSFRS-R decline 
slope ≥ 0.2 per month or a pre-randomization ALSFRS-R decline slope ≥ 0.9 with SOD1 
mutation NOT on the protocol-defined list). This resulted in a total of 12 placebo control 
matched subjects (8 from the historical placebo data [Benatar 2018] and 4 from Study 
233AS101) and 4 matched subjects treated with tofersen 100 mg from interim data of a very 
small cohort in Study 233AS101. The observed mean slope of decline was -3.83 for the matched 
placebo subjects and -0.74 for the matched tofersen 100 mg subjects, with a pooled SD of 3.166. 
In the 12 matched subjects on placebo, there was 1 death and 2 subjects with permanent assisted 
ventilation less than 6 months but none in the tofersen 100 mg matched subjects. Based on this 
and overall survival data in fast progressors from the literature on subjects with an A4V SOD1 
mutation, the survival at Week 28 was assumed to be 82% in the placebo control and 90% in the 
tofersen 100 mg group. 
Under the above assumptions, with N = 60 subjects in the mITT population and a two-sided 
significance level of 0.05, the joint rank test gives 84% power. Because events of death have 
been factored into the analysis, no sample size overage is planned for missing values. 
For the population outside of the mITT population, the primary focus will be on the PD endpoint, 
total CSF SOD1 protein concentration, as this population is anticipated to have a slower decline 
in clinical function compared to the mITT population. A sample size of 26 subjects in the treated 
group and 13 subjects in the placebo group for the population outside of the mITT would provide 
97% power to detect a 25% reduction in total CSF SOD1 from baseline in the treated group, with 
an assumed SD of 0.216 (natural log scale), compared to the placebo group. 
The COVID-19 mitigation plan outlined earlier lowers the risk of missed doses and assessments 
and is in place to avoid the need for a sample size increase. 
4. General Considerations 
 
4.1 Statistical Methods: General Considerations 
 
Descriptive summary statistics will be presented for all primary, secondary and exploratory 
endpoints collected. Unless otherwise specified, for continuous endpoints, the summary statistics 
will generally include number of subjects with data, mean, standard deviation, median, 25th 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
percentile, 75th percentile, minimum and maximum. For categorical endpoints, the summary 
statistics will generally include number of subjects with data, and the percentage of those with 
data in each category. 
 
All summaries and listings will be presented by treatment group unless otherwise specified. For 
the purpose of the efficacy and pharmacodynamic outputs, the mITT and non mITT populations 
will be used to describe the subset of subjects who meet the prognostic enrichment criteria for 
rapid disease progression, and all other eligible subjects, respectively. For the purpose of safety 
and pharmacokinetic outputs, any summaries for disease progression subgroup will present the 
subgroup categories as ‘enriched’ for subjects who meet the prognostic enrichment criteria for 
rapid disease progression, and “other” for all other eligible subjects. Listings will also indicate 
which subgroup the subject belongs to (“enriched” “other”). Visits in listings will be displayed as 
per CRF data collection rather than analysis visits. 
 
Treatment groups will be labelled as “Placebo” and “tofersen 100 mg”. 
 
Unless otherwise specified, the baseline value is defined as the last non-missing value prior to 
first dose. Change from baseline is defined as postbaseline value minus baseline value. 
 
Unless otherwise stated, all statistical tests for primary and secondary efficacy endpoints will be 
2-sided with overall Type I error control at the 5% statistical significance level. 
 
The statistical software, SAS®(Version 9.4) will be used for all summaries and statistical 
analyses. 
 
4.2 Analysis Populations 
• Subjects in Part C Randomized subjects 
These are subjects enrolled who received a randomization treatment assignment from the 
Interactive Response Technology (i.e. tofersen 100 mg or placebo). 
• ITT Population 
The overall ITT population is defined as all subjects in Part C who are randomized and received 
at least 1 dose of study treatment. 
• Modified ITT (mITT) Population 
The modified intent-to-treat (mITT) population is defined as all subjects who meet the 
prognostic enrichment criteria for rapid disease progression in Part C who are randomized and 
received at least 1 dose of study treatment. The criteria are defined in Section 2. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
• Non mITT Population 
This is the subset of subjects in the overall ITT population who are not included in the mITT 
population i.e. all other eligible subjects (criteria defined in Section 2). 
• Per-protocol population 
This is the subset of subjects in the mITT population who did not have a protocol deviation that 
violated the following criteria: 
- 
Missed at least one dose of study drug during the loading dose period (i.e. Day 1 to Day 
29) 
- 
ALSFRS-R not performed by a blinded rater (i.e. not blinded to other assessments for the 
subject) as recorded on the protocol deviation log (or if for some reason the rater was not 
certified at the time of assessment). 
• 
 
 
 
• Safety Population 
The safety population is defined as all subjects in Part C who are randomized and received at 
least one dose of study treatment (i.e. the overall ITT population of subjects in Part C). 
• Immunogenicity Population 
The analysis population for immunogenicity is defined as all subjects who received at least one 
dose of study treatment and have at least 1 postdose sample evaluated for immunogenicity in 
Part C. 
Populations used for analysis 
 
The primary analyses of clinical function will be evaluated in the mITT population, comprising 
the subset of subjects who meet prognostic enrichment criteria for rapid disease progression who 
are randomized and receive at least 1 dose of study treatment. The primary analysis population 
comprised participants who met prognostic enrichment criteria for rapid disease progression to 
enable detection of a statistically significant and clinically meaningful treatment effect on 
clinical function over the 6 month treatment duration. The treatment effect of clinical function 
endpoints outside of the mITT population (i.e. non mITT) will be analyzed where relevant, as 
described in Section 6. The clinical function data in the overall ITT population will be 
summarized and analyzed where appropriate. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
All safety evaluations will be summarized using the safety population. 
 
 
 
There will not be a separate pharmacodynamic population for the PD endpoints
 
 These endpoints will all be analyzed/summarized 
as appropriate for each of the mITT population, the non mITT population and the overall ITT 
population, as described in the relevant sections. 
Dealing with errors in randomization, study drug dispensation and stratification 
 
Analyses using the mITT population, non mITT population and overall ITT population will be 
performed according to the treatment assignment at the time of randomization. 
In case of any subjects who are incorrectly stratified when they are randomized the analyses will 
be based on the treatment they were randomized to. If the subject was stratified to disease 
progression subgroup incorrectly according to prognostic enrichment criteria (“enriched” 
“other”) at randomization, the mITT population will be based on the correct population 
according to the clinical database. For analysis purposes e.g. when summarizing any of the 
stratification factors (population (“enriched” “other”), riluzole use, edaravone use) or including 
in statistical models or subgroup analyses, subjects will be included under the correct 
categorization according to the clinical database. 
For the safety 
 populations, subjects will be analyzed under the actual treatment they 
received. If a subject received one or more doses of tofersen then the subject will be included 
under the tofersen treatment group for safety 
. If a subject only received placebo then the 
subject will be included under the placebo group for safety. 
If a subject is misrandomized, e.g. does not meet eligibility criteria, then the subject will be 
included in the overall ITT and safety populations. Depending on whether the subject is classed 
as part of the “enriched” population or not the subject would also be included under the relevant 
population for the mITT or the non mITT. 
A listing of subjects whose actual treatment assignment is different from their randomized 
treatment group will be provided. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
4.3 Visit Windows for Early Withdrawal, Unscheduled Visits and Early Termination 
Visits in the Event of Early Study Closure 
For subjects who are early terminated (ET), EOS visit is defined as the scheduled follow-up visit 
4 weeks after last dose (i.e. Week 28/Day 197 EOS visit). Week 32/Day 225 is only intended to 
collect adverse events and concomitant medications for participants who do not proceed into the 
233AS102 extension study and thus will not need to be windowed. 
If, due to the COVID-19 pandemic, subjects could not attend clinic visits during protocol defined 
windows, they were given some allowance to have a delayed visit. There may also have been 
subjects who attended visits outside the protocol defined windows for other reasons. Regardless 
of whether the delayed visit was due to the COVID-19 pandemic or not, these are recorded under 
scheduled visits and are also considered to be protocol deviations. Visit windows will not be 
applied to scheduled visits for analysis purposes. If a subject had a phone visit followed by a 
delayed clinic visit, the clinic visit is still recorded as the scheduled visit. The scheduled visit will 
always take precedence over unscheduled visits. 
Data from early withdrawal visits, postbaseline unscheduled assessments and early termination 
visits in the event of early study closure will be assigned to an appropriate scheduled 
postbaseline visit using a windowing scheme for assessments that are tabulated or summarized 
by visit. Scheduled visits will not be windowed. 
The visit windowing for efficacy 
 is given in the tables below: 
 
Table 2: 
Visit Windows for Primary and Secondary Efficacy Endpoints 
 
ALSFRS-R/SVC/HHD 
Visit 
Lower Bound 
Upper Bound 
Target Day 
Day 15 
8 
21 
15 
Day 29 
22 
42 
29 
Day 57 
43 
70 
57 
Day 85 
71 
98 
85 
Day 113 
99 
126 
113 
Day 141 
127 
154 
141 
Day 169 
155 
182 
169 
Day 197 
183 
211 
197 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
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The visit windowing for safety assessments is given in the tables below: 
 
Table 4: 
Visit Windows for Safety Endpoints Part 1 and 
PD/Biomarker Endpoints 
 
Safety Endpoints* 
Visit 
Lower Bound 
Upper Bound 
Target Day 
Day 15 
8 
21 
15 
Day 29 
22 
42 
29 
Day 57 
43 
70 
57 
Day 85 
71 
98 
85 
Day 113 
99 
126 
113 
Day 141 
127 
154 
141 
Day 169 
155 
182 
169 
Day 197 
183 
211 
197 
* This windowing covers the following safety endpoints: vital signs, neurological exam 
(including MMSE), all lab tests (including pregnancy; CSF sampling; lab tests for 
haematology, chemistry, coagulation and urinalysis; urine sample for biomarkers, blood 
samples for anti-BIIB067 antibodies, 
 and blood samples for biomarkers) 
Note: Weight is not collected at Days 15 and 29 so no assessments will be windowed to those 
visits. All other windows are as above. Based on Protocol Version 6, some subjects will have 
MMSE collected less frequently during postbaseline i.e., Days 85, 169 and 197 so these 
subjects will not be summarized at other postbaseline visits. The outputs will include a 
clarification footnote. 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Table 5: 
Visit Windows for Safety Endpoints Part 2 
 
C-SSRS 
ECG* 
Visit 
Lower 
Bound 
Upper 
Bound 
Target 
Day 
Lower 
Bound 
Upper 
Bound 
Target 
Day 
Day 15 
n/a 
n/a 
n/a 
n/a 
n/a 
n/a 
Day 29 
8 
42 
29 
n/a 
n/a 
n/a 
Day 57 
43 
70 
57 
43 
70 
57 
Day 85 
71 
98 
85 
71 
98 
85 
Day 113 
99 
126 
113 
99 
126 
113 
Day 141 
127 
154 
141 
127 
154 
141 
Day 169 
155 
182 
169 
155 
182 
169 
Day 197 
183 
211 
197 
183 
211 
197 
* ECG is not intended to be collected at Days 57, 113 and 141 but due to a misinterpretation a 
substantial number of subjects have ECG collected at these visits and so these data will also be 
summarized. Not all subjects will have data at these additional visits and so the outputs will 
include a clarification footnote. 
 
Considering the high frequency of postbaseline visits and the relatively small gap between 
adjacent visits, the lower bound and the upper bound for the visit windows are based on the 
midpoints of the scheduled visits. The date of first dose will be the reference point (Day 1). 
 
• If more than one observation is within the same window, data from the regular 
scheduled visit will be used for that visit. 
• If neither of the observations are from a regular scheduled visit the 
observation closest to the planned target date will be used. However, if both 
the observations are equidistant from the target date, the latest one will be 
used; if repeated measurements are on the same day, then the last 
measurement will be used. 
• If there is more than one observation in a window for a dosing visit (Day 15 to 
Day 169 visits), the observation on the day of dosing will be chosen over the 
observation where dosing did not occur on the same day. 
• Some of the safety assessments are collected postdose in addition to the 
predose assessments (e.g. vital signs and neurological exam at Day 15 to Day 
169 visits, ECG and MMSE at Day 169, 
 
 When windowing any predose assessments these should be the last 
available assessment prior to the dose. When windowing any postdose 
assessments they should correspond to the same dose as the predose 
assessment used for that visit. These summaries will present predose and 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
postdose separately on by-visit summaries. If one of these assessments is 
collected at an unscheduled visit where there is no dosing, the assessment will 
be assigned as a predose assessment. 
• As a general note, Day 197 should serve as the same visit as Baseline in 
233AS102 for the majority of subjects. The data should be entered under the 
233AS101 Part C database but there may be a few exceptions where the 
incorrect lab kit was used from 233AS102 and so the data are entered under 
Baseline in 233AS102. In that situation where Day 197 for 233AS101 Part C 
and Baseline for 233AS102 are the same visit, the data will be taken from the 
233AS102 database and incorporated into the datasets at the CDISC SDTM 
level. If samples are accidentally collected under both 233AS101 Part C and 
the 233AS102, the data under 233AS101 Part C will be used for Day 197. 
Similarly, for Screening Visit of 233AS102 and Week 24 of 233AS101 Part 
C, data will be taken from 233AS101 Part C Week 24 in case lab kits from 
both studies were used 
 
 
 
 
5. Study Subjects 
 
5.1 Subject Accountability 
The number (and percentage) of subjects randomized; dosed; completed the treatment; 
completed the study; completed the study but missed one or more doses; discontinued treatment 
and the reasons for discontinuation; and withdrew from study early and the reasons for 
withdrawal will be summarized in a table. These summaries will be presented by disease 
progression subgroup (“enriched” “other”) and treatment. 
If there are any subjects who discontinued from treatment or withdrew from study due to 
COVID-19 pandemic related reasons, a separate summary will be presented to summarize 
reasons for discontinuation and withdrawal from study for COVID-19 related reasons. Adverse 
events, deaths and other reasons may fall into COVID-19 related categories. The Other category 
will be broken down into the following categories: 
Other – COVID-19 (Movement Restrictions Related to COVID-19 Pandemic) 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Other – COVID-19 (Subject Fear Related to COVID-19 Pandemic) 
Other – COVID-19 (Site Closed Due to COVID-19 Pandemic) 
Other – COVID-19 
A listing of subjects who discontinued treatment/withdrew from study and the associated reasons 
for discontinuation/withdrawal will be presented. A separate listing will also be presented for 
subjects who discontinued treatment/withdrew from study due to the COVID-19 pandemic. 
The number (and percentage) of subjects randomized by country and site, the number (and 
percentage) of subjects who completed the study by country and site, and number (and 
percentage) of subjects by analysis population will be summarized by disease progression 
subgroup (”enriched” “other”) and treatment group, and for all subjects. 
Listings will be provided to show subjects excluded from each population. 
 
A summary of the stratification factors used for randomization (i.e. disease progression subgroup 
(“enriched” “other”), riluzole use and edaravone use) will also be presented by treatment group 
for all randomized subjects, based on the data in the clinical database. A randomization listing 
will be provided and will include stratification factors (disease progression subgroup (“enriched” 
“other”), riluzole use and edaravone use). 
 
5.2 Demography and Baseline Disease Characteristics 
All demographics and ALS disease history data will be summarized for the mITT population, the 
non mITT population and the overall ITT population by treatment group and overall. 
Demographic data, including age (years), age category (18-<35,35-<50, 50-<65, ≥65), gender, 
ethnicity, race, height, weight and body mass index (BMI). The derivation for BMI is detailed in 
Appendix A. 
 
ALS disease history will also be summarized descriptively and will include summaries of: 
 
• confirmed SOD1 mutation (per analysis report of genetic sample collected at screening) i.e. 
Yes/No 
• protocol defined mutation (i.e. p.Ala5Val, p.Ala5Thr, p.Leu39Val, p.Gly42Ser, p.His44Arg, 
p.Leu85Val, p.Gly94Ala, p.Leu107Val, and p.Val149Gly) (Not applicable for non mITT 
population) 
• mutation type; 
• time since ALS symptom onset (months); 
• time since ALS diagnosis (months); 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
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• site of onset (bulbar, lower limbs, upper limbs, respiratory, thoracic; subjects may be 
summarized under more than one site if subject has multiple sites of onset); 
• pre-randomization ALSFRS-R slope; 
• disease progression subgroup (“enriched” vs “other”); 
• riluzole usage/duration and edaravone usage/duration including number and percentage with 
both riluzole and edaravone use; 
• ALS Milano-Torino Staging (MITOS) at baseline [Chio 2015] described in Appendix B; 
• King’s Stage for ALS at baseline [Balendra 2014] described in Appendix B. 
 
 
A separate table will also be presented for the mITT population that lists the Subject ID, Treatment, 
SOD1 mutation, pre-randomization ALSFRS-R slope, Classification of SOD1 mutation 
(pathogenic/likely pathogenic), time since ALS diagnosis, screening and baseline total ALSFRS- 
R score, screening and baseline percent predicted SVC, time since symptom onset, site of onset, 
riluzole and edaravone usage/duration. 
 
A listing will be presented for all screened subjects with details of the genetic testing at screening, 
including information on those who were reclassified for pathogenicity on their genetic test. 
 
Details for any derivations are given in Appendix A. 
 
Descriptive statistics for baseline clinical function for each of ALSFRS-R total score, percent 
predicted SVC and HHD megascore at screening and baseline will also be presented in a separate 
summary table. The table will also include a summary of total CSF SOD1 protein and NfL in 
plasma at baseline, a summary of whether a subject used a facemask for SVC at screening and 
baseline assessments, and whether a subject had any ventilation use at screening or baseline 
(determined also eDiary records if recorded, from Concomitant Non-Drug Treatment eCRF page 
in addition to the question asked on ALS Disease History eCRF page; the ALSFRS-R question on 
respiratory insufficiency will also be used as a check to ensure consistency). The summary will 
also present number and percentage of subjects with percent predicted SVC <65% at baseline in 
the mITT population, and with percent predicted SVC <50% at baseline in the non mITT 
population. For percent predicted SVC, a summary will also be presented of number and 
percentage of subjects with a baseline assessment that did not meet acceptability and repeatability 
ATS criteria A per Appendix B. 
 
Medical history will be classified using MedDRA version 24.0. A summary of medical history by 
system organ class and preferred term will also be provided for the safety population. All 
demographics, baseline characteristics, disease history and medical history will also be listed. 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
A listing of subjects who transferred sites will also be included with the site ID for transferring 
and receiving site as well as the timing of the transfers. 
 
5.3 Extent of Exposure and Study Drug Compliance 
Summaries for extent of exposure to study treatment and study drug compliance will be 
summarized for the mITT population, the non mITT population and the overall ITT population. 
A frequency distribution for number of doses received per subject will be summarized by 
treatment group, and descriptive statistics will be presented for total cumulative dose in mg. 
Total cumulative dose will be based on actual dose administered (calculated as volume 
administered multiplied by dose, and divided by 15mL). 
Based on Phase 1 data from Part B following withdrawal of study drug and the half-life of 
tofersen (~1 month), missing more than 2 consecutive doses within the 24 week study period is 
considered likely to impact pharmacodynamic and efficacy results. Figure 2 shows the Phase 1 
MAD observed data for ALSFRS-R total score in the tofersen 100 mg and placebo subjects who 
completed the study with data at all visits. The last dose is at Day 85, and ALSFRS-R shows a 
rebound at Day 169 after study drug withdrawal (i.e. approximately 3 months after the last dose). 




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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
The following summaries will be presented by treatment group within each of the mITT, non 
mITT and overall ITT populations: 
• Total number of expected doses across subjects based on actual subject duration in study; 
total number of missed doses and total number of delayed doses (percentages calculated 
out of total number of expected doses); 
• A frequency distribution for number of consecutive missed doses per subject; 
• A frequency distribution for overall number of missed doses per subject (i.e. regardless of 
whether they were consecutive). The mean (SD) will be presented for the mean number 
of missed doses per subject. Subjects with no missed doses will be included as having 0 
missed doses. 
• The mean (SD) number of delayed doses per subject will also be summarized. Subjects 
with no delayed doses will be included as having 0 delayed doses. A delayed dose is 
defined in Table 6 based on regular scheduled visits, as dosing cannot be recorded under 
unscheduled visits. 
• A by-visit summary will also show the number of subjects who missed a dose at that visit 
i.e. no dose recorded at the regular scheduled visit. 
 
The summaries described above for missed and delayed doses will be repeated based on doses 
that are missed or delayed due to COVID-19 impact. 
A listing will also be presented to show dosing history for all subjects who missed at least one 
dose, indicating whether any of the missed doses are related to COVID-19. If any of the doses 
are due to COVID-19, then the number of impacted doses will be presented. 
Study drug compliance percentage up to the last dose of study drug received will be defined as 
the number of doses actually received divided by the number of doses that the subject is expected 
to receive during the study period and will be summarized by descriptive statistics. For subjects 
who withdrew from study early, the number of expected doses is the planned number of doses 
before the time of study withdrawal. 
Separate listings will be provided showing what subjects were randomized to as well as study 
drug administration data which will include lot numbers, actual treatment received, cumulative 
number of doses and cumulative dose. A listing of dosing errors will also be provided i.e. where 
either the incorrect dose was administered as specified in protocol deviation log and kit 
description from IRT system, or where less than 15mL of study drug was administered. Actual 
dose will be calculated as volume administered multiplied by dose, and divided by 15mL. The 
nominal dose will also be presented. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
A listing of study drug administration records for placebo subjects who received any active 
treatment will be provided. 
Time on study will be summarized descriptively by treatment. Overall time on study will be 
calculated as last date on study – first dose date + 1 in days. Last date on study is defined as the 
date of the latest visit or evaluation or telephone contact, or time of death from all available data 
for a given subject. The durations will also be categorized and summarized using the following 
categories: ≤29 days, >29 to 57 days, >57 days to 85 days, >85 to 113 days, >113 to 141 
days, >141 to 169 days, >169 to 197 days, >197 days. 
 
Subjects are considered to be exposed to study drug for approximately 5 half-lives. Therefore, 
given the half-life of tofersen (approximately 1 month), subjects would be considered to be 
exposed to study drug for 5 months after their last dose. Based on the 6-month duration of the 
study, a separate summary for exposure will not be provided. However, a summary of time to 
treatment discontinuation will be provided for those subjects who discontinued study drug, 
calculated as last dose date – first dose date +1. 
 
5.4 Concomitant Medications and Non-Drug Treatments/Procedures 
Concomitant medications will be coded using the World Health Organization (WHO) dictionary 
WHODRUG (March 2021) and concomitant non-drug treatments/procedures using the Medical 
Dictionary for Regulatory Activities (MedDRA) version 24.0. 
Medications and non-drug treatments are considered concomitant if they are taken during the 
study. This includes medications/treatment/procedures that were started prior to the date and 
time of first dose of study drug if their use continued on or after the date and time of first dosing. 
If the start date is available but start time is missing and the medications/treatment/procedure 
start date is the same as the first dose date, the medications/treatment/procedure will be 
considered concomitant. Similarly, if the stop date is available but stop time is missing and the 
medications/treatment/procedure stop date is the same as the first dose date, the 
medications/treatment/procedure will also be considered concomitant. 
Medications/treatment/procedures with missing start or stop dates and times, will also be 
considered as concomitant in the following situations: 
• If both the start and stop dates and times of a medication/treatment/procedure are 
missing; 
• If the start date and time of a medication/treatment/procedure is missing and the stop date 
and time of the medication/therapy occurred on or after the date and time of first dose of 
study drug; 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
• If the start date and time of a medication/treatment/procedure therapy occurred prior to 
the date and time of first dose of study drug and the stop date and time of the 
medication/treatment/procedure is missing and the medication/treatment/procedure is 
listed as ongoing; 
In a rare situation where the start date and time of a medication/treatment/procedure occurred 
prior to the date and time of first dose of study drug and both the stop date and time of the 
medication/treatment/procedure is missing and the medications/treatment/procedure is not listed 
as ongoing, then the medication/treatment/procedure will also be considered as concomitant. 
For medications/treatment/procedures with a partial start date, the year/month will be compared 
to that of the first dosing date to determine whether the medications/treatment/procedure is 
concomitant. 
The number and percentage of subjects taking any concomitant medications will be summarized 
by treatment group for the safety population. The number and percentage of subjects taking any 
concomitant non-drug treatments will also be summarized by treatment group for the safety 
population. 
A review of concomitant medications will be performed by a medical reviewer to identify 
disallowed medications as defined in the protocol. This review will be on an ongoing basis prior 
to the database lock and unblinding for this study. A summary showing the number and 
percentage of subjects taking any disallowed concomitant medication will be summarized by 
treatment group for the safety population. 
These summaries will also be presented by disease progression subgroup (“enriched” “other”). 
All medications/treatment/procedures will also be listed. 
A listing of any changes to riluzole or edaravone use during the study will be presented. 
 
If there are a sufficient number of tests or treatments reported with indication of COVID-19, a 
separate summary of these will be provided. This will include a summary of the number and 
percentage of subjects with COVID-19 diagnostic tests with the following recorded verbatim 
terms (these will be coded using MedDRA dictionary): 
 
“COVID-19 Diagnostic Test Result Positive” 
“COVID-19 Diagnostic Test Result Negative” 
“COVID-19 Diagnostic Test Result Pending” 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
“COVID-19 Diagnostic Test Result Inconclusive” 
 
and the number and percentage of subjects with COVID-19 antibody tests with the following 
recorded verbatim terms (these will be coded using MedDRA dictionary): 
 
“COVID-19 Antibody Test Result Positive” 
“COVID-19 Antibody Test Result Negative” 
“COVID-19 Antibody Test Result Pending” 
“COVID-19 Antibody Test Result Inconclusive” 
If there are very few COVID-19 tests or treatments the summary will not be presented but a 
listing of these will be provided. 
 
5.5 Protocol Deviations and Compliance 
Protocol deviations identified during site monitoring will be captured in a protocol deviation log. 
All protocol deviations will be listed and a summary of major protocol deviations by treatment 
group will also be provided for each of the mITT population, non mITT population and overall 
ITT population. A separate listing will present site level deviations for deviations that do not 
impact any subjects (e.g. temperature excursions where no subjects were administered impacted 
doses), 
Subjects with incorrect stratification i.e. any mismatch between the stratification used for 
randomization on the IRT system and the actual stratification according to the eCRF will also be 
listed. A separate summary of major protocol deviations related to the COVID-19 pandemic will 
be presented. A listing will also present all minor and major PDs related to the COVID-19 
pandemic. 
A summary will be presented by visit and overall showing the number and percentage of subjects 
with the following type of visit: 
Clinic visit (with dosing) 
Clinic visit (with no dosing) 
Home visit only 
Home visit and telephone visit 


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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Telephone visit only 
Missed visit 
The overall summary will be based on number of expected visits. This summary will also present 
the number of delayed visits (i.e. outside protocol defined window as per Table 6) per subject 
across the study and the number of missed visits per subject. 
A summary showing the number and percentage of subjects by visit will be presented with the 
breakdown of the reason for the missed visit i.e. 
COVID-19 – Subject diagnosed with Covid-19 disease 
COVID-19 – Subject fear related to Covid-19 pandemic 
COVID-19 – Movement restrictions related to Covid-19 pandemic 
COVID-19 – Site closed due to COVID-19 pandemic 
Other 
 
This summary will also show the total number of visits missed per subject for each reason. 
 
Although only a protocol deviation before Protocol Version 6, a summary will be provided to 
show number of ALSFRS-R raters per site (i.e. mean and SD, as well as frequency distribution). 
The summary will also indicate number and percentage of subjects assessed by a rater that was 
not blinded to other assessments, as well as number of visits affected per subject. The proportion 
of assessments not rated by a blinded rater will also be presented (i.e. total number of 
assessments across all sites and subjects not performed by a blinded rater over total number of 
expected assessments). 
The acceptability criteria for SVC is defined in Appendix B of this SAP. The number and 
percentage of subjects with a least one invalid reading graded F according to the ATS criteria 
will be presented, as well as number of visits per subject with an invalid reading. 
Subjects who use a facemask for the SVC assessment should ideally use throughout the 
subsequent assessments. The number of subjects with an SVC reading at both baseline and Day 
197 will be presented. Of these, the number and percentage of subjects with facemask use will be 
presented as follows: 
• Those who used a facemask at both baseline and Day 197 
• Those who did not use a facemask at baseline and Day 197 


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Statistical Analysis Plan 
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• Those with inconsistent or missing facemask use at baseline and Day 197 
At Site 
, a HHD rater performed this assessment for 3 subjects after 
 certification expired at 
multiple visits. These subjects are all in the non mITT population. In addition, due to the ALSFRS- 
R rater at this site not being available during the COVID-19 pandemic, the ALSFRS-R for one of 
these subjects was also performed by a non-certified rater. This impacted only 1 subject (
) 
at 2 unscheduled visits that are not mapped to any regular scheduled visits and therefore impacts 
no analysis. These are all recorded as protocol deviations. For HHD these deviations will be 
included in the main analyses but will be assessed via sensitivity analysis. Although action has 
been taken to mitigate risk of non-certified raters performing assessments, any additional cases 
will be documented as protocol deviations and handled in the same way for analysis. If ALSFRS- 
R is impacted at any regular visits that are required for analysis, a sensitivity analysis will be 
conducted for non-mITT. For mITT this would be handled via the Per-protocol population. 
At the same site (
), there was a subject who had C-SSRS performed by non-certified raters. 
These are also recorded as protocol deviations. As this is a safety assessment all data will be used 
for analysis of C-SSRS. 
 
5.6 Protocol Alternations 
Protocol alternations are alternative methods of assessments due to the COVID-19 pandemic. 
For subjects who could not attend clinic visits due to the pandemic, protocol alternations in place 
for this study are home visits or telephone assessments. A listing of subjects with protocol 
alternations will be provided. 
6. Efficacy Data 
 
6.1 General Considerations 
The primary efficacy population (mITT) will be used for all analyses of efficacy data. In 
addition, descriptive statistics and/or analyses may also be performed on the non mITT 
population as specified. Although it is unlikely that any testing of clinical function endpoints will 
show statistical significance in the non mITT population given the study duration, nominal p- 
values will be presented. For the overall ITT population, there will be no formal testing. 
Unless stated otherwise, baseline data are defined as the data collected prior to the time and/or on 
the date of first dose, which is usually the same day as the Day 1/Baseline visit. If there is more 
than one value on/before the date of the first dose, the non-missing value closest to and prior to 
the first dose will be used as the baseline value. 


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For each of the primary efficacy and secondary efficacy endpoints the key analysis which is in 
the mITT population and is used for formal testing is classed as the ‘primary analysis’ for that 
efficacy endpoint. 
The analyses in the non mITT population are classed as secondary analyses of each of the 
primary and secondary efficacy endpoints, as are other definitions for the endpoint and/or time 
point analyzed. An alternative test such as a non-parametric test, or any other analysis to check 
the robustness of the assumptions for the primary analysis is classed as a sensitivity analysis i.e. 
any analysis that confirms that the estimate derived is reliable for interpretation. All other 
analyses are classed as supplementary analyses i.e. any analyses to more fully investigate and 
understand the data. 
The primary, secondary, sensitivity and supplementary analyses for the primary and key 
secondary efficacy endpoints are listed in Tables 7 and 8. 
Table 7 
Analysis for Primary Efficacy Endpoint 
 
Endpoint 
Analysis 
Analysis 
Populations 
SAP 
Section 
Change from 
baseline in 
ALSFRS-R total 
score at Week 
28/Day 197 
Primary: Joint Rank methodology using 
multiple imputation (MI); analysis of 
ranked scores using analysis of 
covariance 
mITT 
6.2.1 
Sensitivity: Joint Rank methodology; 
analysis using generalized Gehan- 
Wilcoxon test 
mITT 
6.2.2 
Sensitivity: multiple imputation (MI) to 
impute missing values; analysis of 
covariance (ANCOVA) with covariates 
for Day 197. LS Mean Treatment 
differences, 95% CI and p-values at 
visits other than Day 197 will also be 
presented as secondary analyses by 
fitting separate ANCOVA for each visit 
mITT 
6.2.2 
Sensitivity: subjects who died will be 
excluded from the MI model; joint rank 
p-value only 
mITT 
6.2.2 
Sensitivity: Trimmed Mean 
mITT 
6.2.2 


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Sensitivity: Tipping point analysis for 
primary efficacy (Joint Rank + MI): p- 
values from each shift parameter 
mITT 
6.2.2 
Sensitivity: Tipping point analysis for 
primary efficacy (ANCOVA + MI): 
LS Mean Treatment differences, 95% 
CI and p-values based on ANCOVA for 
Day 197 presented for each shift 
parameter 
mITT 
6.2.2 
Sensitivity: Include baseline plasma 
NfL as an additional covariate in 
ANCOVA model for both ranked 
scores and for change from baseline: MI 
to impute missing values: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits; p-value from joint 
rank will also be presented. As 
secondary analysis all visits other than 
Day 197 will also be presented. 
mITT 
6.2.2 
Secondary: MI to impute missing 
values; ANCOVA including covariates 
– performed for each postbaseline visit; 
LS Mean Treatment differences, 95% 
CI and p-values at all visits 
non mITT 
6.2.2 
Secondary: joint rank test to obtain p- 
value where permanent ventilation is 
incorporated as an event; analysis of 
ranked scores using analysis of 
covariance 
mITT 
6.2.3.1 
Secondary: joint rank test to obtain p- 
value where permanent ventilation and 
withdrawals due to disease progression 
are incorporated as an event; analysis of 
mITT 
6.2.3.2 


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ranked scores using analysis of 
covariance 
Secondary: Include baseline plasma 
NfL as an additional covariate in 
ANCOVA model: MI to impute 
missing values at each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits. 
non mITT 
6.2.2 
Supplementary: Q5a and Q11 from 
Japanese Ohashi version of ALSFRS-R 
for Japanese subjects used; Joint Rank 
methodology 
mITT 
6.2.4.1 
Supplementary: Exclusion of Japanese 
subjects; Joint Rank methodology 
mITT 
6.2.4.1 
Supplementary: Q5a and Q11 from 
Japanese Ohashi version of ALSFRS-R 
for Japanese subjects used; MI to 
impute missing values for each visit: 
ANCOVA including covariates – 
performed for each postbaseline visit; 
LS Mean Treatment differences, 95% 
CI and p-values at all visits 
mITT 
non mITT 
6.2.4.1 
Supplementary: Exclusion of Japanese 
subjects; MI to impute missing values 
for each visit: ANCOVA including 
covariates – performed for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits 
mITT 
non mITT 
6.2.4.1 
Supplementary: If such protocol 
deviations occur, exclusion of 
assessments by non-certified rater 
across sites; MI to impute missing 
values – the values for assessments by a 
non-certified rater at affected visits will 
be set to missing and instead imputed 
values used; ANCOVA including 
non mITT 
6.2.4.2 


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covariates – performed for Day 197; LS 
Mean Treatment difference, 95% CI 
and p-value. 
Supplementary: Exclusion of mITT 
subjects with percent predicted SVC 
<65% at baseline: MI to impute missing 
values for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits; p-value from joint 
rank will also be presented 
mITT 
6.2.4.3 
Supplementary: exclusion of 
prespecified protocol deviations from 
the mITT; MI to impute missing values 
for each visit: ANCOVA including 
covariates – performed for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits; P-value from joint rank will also 
be presented 
Per-protocol 
6.2.4.4 
Supplementary: Exclusion of carriers of 
SOD1 mutations characterized as 
“indeterminate” ) (i.e., heterozygous 
D91A carriers); MI to impute missing 
values for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits; p-value from joint 
rank will also be presented 
mITT 
6.2.4.6 
Subgroup analysis: Subjects with pre- 
randomization slope decline ≥0.9; 
missing data imputed using multiple 
imputation model for this subset of 
subjects for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits; p-value from joint 
rank will also be presented 
mITT 
6.5 


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Subgroup analysis for gender, baseline 
disease duration since symptom onset, 
baseline NfL plasma level, site of onset, 
geographic region and 
riluzole/edaravone use: MI to impute 
missing values for each visit: 
ANCOVA including covariates – 
performed for each postbaseline visit; 
LS Mean Treatment differences, 95% 
CI and p-values at all visits; (no p- 
values for overall ITT) 
Observed data descriptive statistics. 
mITT 
non mITT 
Overall ITT 
6.5 
Additional analysis : missing data 
imputed using multiple imputation 
separately for mITT and non mITT; 
ANCOVA includes both populations i.e 
disease progression subgroup 
(‘enriched’ ‘other’) in the model and 
interaction for disease progression 
subgroup by treatment as well as 
covariates – performed for Day 197; LS 
Mean treatment difference for each 
subgroup and across the subgroups and 
corresponding 95% CI 
Overall ITT 
6.2.5 
Additional analysis: missing data 
imputed using multiple imputation 
model for this subset of subjects; 
ANCOVA using MI includes only 
subjects with slope decline ≥0.9 from 
Screening to Day 15 inclusive. The 
ANCOVA will be performed for Day 
197 and will include covariates; LS 
mean treatment difference, 95% CI and 
p-value; p-value from joint rank will 
also be presented 
Subset of 
Overall ITT 
6.2.5 
Additional analysis : includes only 
subjects from mITT with slope decline 
≥0.9 from Screening to Day 15 
inclusive. MI model will include this 
subset of subjects. The ANCOVA using 
MI will be performed for Day 197 and 
Subset of 
mITT 
6.2.5 


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will include covariates; LS mean 
treatment difference, 95% CI and p- 
value; p-value from joint rank will also 
be presented 
ALSFRS-R slope of 
decline 
Supplementary: slope of decline 
analyzed using analysis of covariance; 
supportive analysis for ranked data 
using Mann-Whitney test 
mITT 
non mITT 
6.2.4.5 
ALSFRS-R changes 
from baseline at 
each visit 
Secondary: missing data imputed using 
multiple imputation separately for 
mITT and non mITT; ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI 
Overall ITT 
6.2.3 
ALSFRS-R actual 
values and changes 
from baseline at 
each visit 
Secondary: observed data; descriptive 
statistics only 
mITT 
non mITT 
overall ITT 
6.2.3 
 
 
Table 8 
Analysis for Secondary Efficacy Endpoints 
 
Endpoint 
Analysis 
Analysis 
Populations 
SAP 
Section 
Change from 
baseline in percent 
predicted SVC at 
Week 28/Day 197 
Primary: Joint Rank methodology using 
multiple imputation (MI); analysis of 
ranked scores using analysis of 
covariance 
mITT 
6.3.1.1 
Sensitivity: Joint Rank methodology; 
analysis using generalized Gehan- 
Wilcoxon test 
mITT 
6.3.1.2 
Sensitivity: MI to impute missing 
values for each visit: ANCOVA 
including covariates for Day 197. 
LS Mean Treatment differences, 95% 
CI and p-values at visits other than Day 
197 will also be presented; separate 
mITT 
6.3.1.2 


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ANCOVA for each visit as secondary 
analysis 
Secondary: MI to impute missing 
values for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at visits other than Day 197 will 
also be presented 
non mITT 
6.3.1.2 
Supplementary: exclusion of subjects 
who wore a facemask inconsistently at 
baseline and Day 197 visits : MI to 
impute missing values: ANCOVA 
including covariates for Day 197; LS 
Mean Treatment differences, 95% CI 
and p-value; p-value from joint rank 
will also be presented 
mITT 
6.3.1.3 
Supplementary: exclusion of 
prespecified protocol deviations from 
the mITT; MI to impute missing values 
for each visit: ANCOVA including 
covariates – performed for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits; p-value from joint rank will also 
be presented 
Per-protocol 
6.3.1.3 
Subgroup analysis: Subjects with pre- 
randomization slope decline ≥0.9; 
missing data imputed using multiple 
imputation model for this subset of 
subjects for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI and p- 
values at all visits; p-value from joint 
rank will also be presented 
mITT 
6.5 
Subgroup analysis for gender, baseline 
disease duration since symptom onset, 
baseline NfL plasma level, site of onset, 
geographic region and 
mITT 
non mITT 
overall ITT 
6.5 


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riluzole/edaravone use: MI to impute 
missing values for each visit: 
ANCOVA including covariates – 
performed for each postbaseline visit 
and/or descriptive statistics based on 
observed data; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits if using ANCOVA (no p-values 
for overall ITT) 
Percent predicted 
SVC actual values 
and changes from 
baseline at each 
visit 
Sensitivity: observed data; descriptive 
statistics only 
mITT 
non mITT 
overall ITT 
6.3.1.2 
Percent predicted 
SVC changes from 
baseline at each 
visit 
Secondary: missing data imputed using 
multiple imputation separately for 
mITT and non mITT; ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI 
Overall ITT 
6.3.1.2 
Change from 
baseline in HHD 
megascore at Week 
28/Day 197 
Primary: MI to impute missing values 
for each visit: ANCOVA including 
covariates for Day 197 – also performed 
as secondary analysis for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at 
visits other than Day 197 will also be 
presented 
mITT 
6.3.2.1 
Secondary: MI to impute missing 
values for each visit: ANCOVA 
including covariates – performed for 
each postbaseline visit 
LS Mean Treatment differences, 95% 
CI and p-values at visits other than Day 
197 will also be presented 
non mITT 
6.3.2.2 
Supplementary: Exclusion of subjects 
assessed by non-certified rater across 
sites; MI to impute missing values – the 
mITT 
non mITT 
6.3.2.3 


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values for assessments by a non- 
certified rater at affected visits will be 
set to missing and instead use imputed 
values: ANCOVA including covariates 
– performed for Day 197 
LS Mean Treatment difference, 95% CI 
and p-value 
Supplementary: exclusion of 
prespecified protocol deviations from 
the mITT; MI to impute missing values 
for each visit: ANCOVA including 
covariates – performed for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits 
Per-protocol 
6.3.2.3 
Supplementary: Upper and lower 
extremities HHD megascore; MI to 
impute missing values: ANCOVA 
including covariates – performed at 
each visit 
LS Mean Treatment difference, 95% CI 
and p-value 
mITT 
non mITT 
6.3.2.3 
Subgroup analysis: Subjects with pre- 
randomization slope decline ≥0.9; MI 
model will include only this subset of 
patients to impute missing values for 
each visit: ANCOVA including 
covariates – performed for each 
postbaseline visit; LS Mean Treatment 
differences, 95% CI and p-values at all 
visits 
mITT 
6.5 
Subgroup analysis for gender, baseline 
disease duration since symptom onset, 
baseline NfL plasma level, site of onset, 
geographic region and 
riluzole/edaravone use : MI to impute 
missing values for each visit: 
ANCOVA including covariates – 
performed for each postbaseline visit 
and/or descriptive statistics; LS Mean 
Treatment differences, 95% CI and p- 
mITT 
non mITT 
overall ITT 
6.5 


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values at all visits if using ANCOVA 
(no p-values for overall ITT) 
HHD megascore 
actual values and 
changes from 
baseline at each 
visit 
Sensitivity: observed data; descriptive 
statistics only 
mITT 
non mITT 
overall ITT 
6.3.2.2 
HHD megascore 
changes from 
baseline at each 
visit 
Secondary: missing data imputed using 
multiple imputation separately for 
mITT and non mITT; ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI 
Overall ITT 
6.3.2.2 
HHD upper and 
lower extremities 
megascore actual 
values and changes 
from baseline at 
each visit 
Supplementary: observed data; 
descriptive statistics only 
mITT 
non mITT 
overall ITT 
6.3.2.3 
HHD upper and 
lower extremities 
megascore changes 
from baseline at 
each visit 
Supplementary: missing data imputed 
using multiple imputation separately for 
mITT and non mITT; ANCOVA 
including covariates – performed for 
each postbaseline visit; LS Mean 
Treatment differences, 95% CI 
Overall ITT 
6.3.2.3 
Time to death or 
permanent 
ventilation 
Primary: stratified log-rank test and 
Cox proportional hazards model 
mITT 
6.3.3.1 
Secondary: stratified log-rank test and 
Cox proportional hazards model 
non mITT 
Overall ITT 
6.3.3.2 
Supplementary: time to death or 
mechanical ventilation for ≥22 hours 
per day for ≥7 consecutive days 
mITT 
non mITT 
Overall ITT 
6.3.3.3 
Supplementary: time to death or 
mechanical ventilation for ≥22 hours 
per day for ≥21 consecutive days using 
imputed data 
mITT 
non mITT 
Overall ITT 
6.3.3.3 


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Time to death 
Primary: stratified log-rank test and 
Cox proportional hazards model 
mITT 
6.3.4.1 
Secondary: stratified log-rank test and 
Cox proportional hazards model 
non mITT 
Overall ITT 
6.3.4.2 
 
 
Derivation of efficacy endpoints 
 
The derivations for each clinical function are provided in Appendix B. 
 
Covariates 
 
The covariates for the statistical models will be as follows: 
 
• Corresponding baseline score for the endpoint (continuous) 
• Baseline disease duration since symptom onset as derived in Appendix A i.e. time since 
symptom onset in months (continuous) 
• Riluzole or Edaravone use which will take 3 levels as follows: 
o Edaravone Use (Edaravone = Yes; Riluzole = Yes OR No) 
o Riluzole Only (Riluzole = Yes and Edaravone = No) 
o Neither (Edaravone = No and Riluzole = No) 
Edaravone use may only occur for a very small number of subjects in which case this could 
cause problems for statistical modelling. If Edaravone use is limited to <5 subjects within the 
relevant population (i.e. mITT or non mITT) then riluzole and edaravone use will be combined 
so that there are only 2 levels: 
- 
Edaravone or Riluzole Use (Edaravone = Yes and Riluzole = Yes; OR 
Edaravone = Yes and Riluzole = No; OR Edaravone = No and 
Riluzole=Yes) 
- 
Neither (Edaravone = No and Riluzole = No) 
For ANCOVA models for percent predicted SVC the model will also adjust for baseline 
ALSFRS-R total score. Given that there is a restriction on SVC for enrolment into the study the 
rate of progression may not be adequately adjusted for based on duration since symptom onset 
and baseline SVC alone; baseline ALSFRS-R score is more likely to reflect stage of disease and 
rate of progression in combination with these other covariates. 
Missing data summaries 


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A summary of missing data by visit and overall for each of the following assessments will be 
presented. The summary will also be broken down by whether the visit was missed due to 
COVID-19 or other reason. These will include missing data after withdrawal to show the extent 
of data imputed for analysis. 
• ALSFRS-R 
• SVC 
• HHD 
• Plasma collection for biomarkers 
• CSF collection for biomarkers 
 
 
A summary of each of the above assessments will also be presented to show the number and 
percentage of subjects at each visit broken down by the type of visit conducted for that 
assessment and if a clinic visit was not conducted whether the alternative method implemented 
was due to COVID-19.
 
All summaries will be presented for each of the mITT, non mITT and ITT populations. 
Missing data for individual items in scales 
The imputation of individual components of each endpoint are described in Appendix B. 
Imputation will be performed within a scale for each endpoint by prorating the observed scores 
at the same visit, for example, if there are missing responses to some of the individual questions 
on a scale at a given visit the endpoint may only be derived for that visit if there are a certain 
number of individual items/components with available data. Specific details are provided for 
each assessment/scale in Appendix B, as this differs across assessments/scales. These 
imputations within a visit will be performed prior to applying imputations on the endpoint at the 
visit level (e.g. multiple imputation) and will be applied consistently across visits where required. 
Multiple imputation will not be applied on an individual item/question within an 
assessment/scale. 
Last observation carried forward (LOCF) 
As there is not likely to be meaningful change between Day 169 and Day 197 in CSF and plasma 
biomarkers (i.e. total CSF SOD1 protein and neurofilament), last observation carried forward 
(LOCF) approach will be used as a sensitivity analysis to impute Day 197, when missing, as long 
as there is a result available at Day 169. The primary analysis of these endpoints will use MI to 
impute all missing values. 


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Protocol 233AS101 
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CSF samples are linked to dosing visits as this requires a lumbar puncture. If a subject cannot 
attend the clinic for a visit, the CSF sample cannot be collected. For subjects who do not 
continue into 233AS102 or those subjects who cannot attend the clinic for their Day 197 visit 
and have a delayed enrolment into 233AS102, these subjects are likely to have a missing CSF 
sample at Day 197. LOCF will be used to impute missing values at Day 197 for CSF and plasma 
biomarkers listed above, where the patient has Day 169 data available. Otherwise MI will be 
applied. Based on Phase 1 data, this approach is conservative as the value 1 month after dosing is 
either flat or further reducing so the levels remain relatively stable over time. The imputed value 
at Day 197 will be used for the analysis of these endpoints. Data at other timepoints will be 
imputed using multiple imputation. If neither Day 169 nor Day 169 values are available, multiple 
imputation will be used to impute these values. 
Figure 3 shows the Phase 1 MAD observed data for total CSF SOD1 in the tofersen 100 mg and 
placebo subjects who completed the study with data at all visits. The last dose is at Day 85, and 
total CSF SOD1 is still stable at Day 106 but there is a slight rebound at Day 169 in subjects who 
received tofersen 100mg. 




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Protocol 233AS101 
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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
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Figure 4: Phase 1 MAD Data for NfL in Plasma in Completers (tofersen 100 mg vs Placebo) 
 
 
Multiple imputation (MI) 
Missing data for postbaseline assessments (Day 15 through to Day 197 visits) will be imputed 
using the multiple imputation method [Schafer 1997, Schafer 1999]. Any missing data for 
baseline will also be imputed if there is no assessment available on or prior to Day 1. Visit 
windowing as described in Section 4.3 will be applied prior to any imputations. Any imputation 
on an item level within a scale will be performed prior to performing MI (see Appendix B). 
LOCF for CSF and plasma biomarkers will also be applied to Day 197 prior to performing MI, 
as described earlier in this section for the purpose of sensitivity analysis. 
MI will be performed on actual values, domains, total scores or summary scores depending on 
the endpoint and not performed at the item level; the complete datasets can then be used to 
calculate change from baseline. 
All available data will be used where subjects have missed doses but continued to perform 
assessments; otherwise any missing values will be imputed using MI. A subject may discontinue 
treatment but may still continue in the study, for example, if a subject has disease progression 


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home visits may be conducted at the discretion of the investigator. In this situation, all available 
data will be used. Only data after withdrawal from study will be imputed in this scenario. 
The Markov Chain Monte Carlo (MCMC) will be used under the multivariate normality 
assumption to impute the missing postbaseline scores in the endpoint by treatment group. As 
some subjects will have intermittent missing data and other subjects will only have data missing 
in a monotone manner, the MI model will be run iteratively so that data will be imputed up to 
and including the first intermittent missing record. 
Prior to performing multiple imputation, the dataset will be sorted by ascending unique subject 
identifier (USUBJID). The treatment variable and riluzole/edaravone use will be coded for 
inclusion in the MI model. The variable list in the model for imputations will include treatment 
group, riluzole/edaravone use, the corresponding baseline value for the endpoint, and all 
available postbaseline values. The MI model will be performed by population (mITT and non 
mITT). A set of 100 complete imputed datasets will be generated. This number of imputed 
datasets needs to be large enough for applying the multiple imputation method in this study as 
the sample size is small. The relative efficiency parameter will also be checked to determine the 
acceptability of the imputed results i.e. it should be close to 98% or higher. The seed used for the 
multiple imputation is specified in Table 9. 
Table 9: Seed used for each endpoint in MI 
 
Endpoint 
Seed 
ALSFRS-R 
Bulbar function 
Respiratory function 
Fine motor skills 
Gross motor skills 
(Total score will not be imputed separately; 
instead the imputed datasets from the 
functional domains will be used to calculate 
the total score. A separate model will be used 
for each functional domain.) 
5846892 
Percent predicted SVC 
8746890 
HHD megascore (overall, upper extremities, 
lower extremities) 
4279059 
 
 




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percent predicted SVC), baseline disease duration since symptom onset and use of riluzole or 
edaravone (as specified in Section 6.1 under Covariates). The model will be used to present 
overall LS means and standard errors for each treatment group, and LS mean differences for 
treatment with corresponding 95% CI. 
Joint rank methodology 
The joint rank methodology [Berry 2013] allows for a statistical test of the treatment effect on 
the endpoint while accounting for truncation of data due to deaths. In this analysis, a subject’s 
joint rank score will be calculated by comparing each subject to every other subject in the study, 
resulting in a score of +1 if the outcome was better than the subject being compared, -1 if worse, 
and 0 if the same. The subject’s score will then be calculated by summing their comparison to 
all the other subjects in the study. 
For the purpose of this calculation, subjects will be grouped into the following 2 categories: 
• Group 1: Subjects who complete the study and have data available at the Day 197 
assessment AND subjects who withdraw from the study due to reasons other than death; 
• Group 2: Subjects who die 
The criteria for withdrawals are based on withdrawal from study. A subject may discontinue 
treatment but still continue in the study. Data from assessments conducted after treatment will be 
included for analysis. 
Joint rank methodology + MI 
MI will be used to impute all missing data before determining the rank score, including data after 
withdrawal from the study except after death. MI will be performed as described earlier in this 
section. Subjects who died will be included in the MI model but any values imputed after death 
will not be used for determining the rank score. Therefore, all subjects except withdrawals due to 
death will have a value at Day 197 (either observed or imputed). 
In each of the 100 imputed datasets, subjects will be ranked as follows: 
• Subjects in Group 2 will be given lower ranks than subjects in Group 1, with the lowest 
ranks being given to the subjects who die in the shortest time after first dose. 
Progressively higher ranks will be given to subjects who die at longer times after first 
dose. 
• Subjects in Group 1 will rank higher than subjects in Group 2. Progressively higher ranks 
will be given to subjects with a higher change from baseline at Day 197 i.e. smaller 
decline at Day 197. 
 
For example, for 2 subjects in Group 1 their comparison score will be based on the endpoint of 
Day 197 change from baseline in ALSFRS-R (or SVC). The subject being ranked will be given 


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a comparison score of -1 if their ALSFRS-R (or SVC) change from baseline is worse than that of 
the comparison subject. If the change is the same in both subjects their comparison will be 
considered a tie and so a comparison score of 0 will be assigned. 
For subjects who do not survive, a subject who dies earlier than the comparator subject will be 
given a comparison score of -1. 
If two subjects die the same number of days from their first dose of study medication their 
comparison will be considered a tie i.e. comparison score of 0 will be assigned. 
The subjects will be ranked according to their subject rank scores in each of the 100 MI datasets. 
In the instance of ties, the mean of the corresponding ranks will be assigned. Hence, in general, 
these comparisons will result in subjects who die being assigned the worst scores and ranked 
according to time of death. Subjects who survive and complete the study and subjects who 
withdraw from the study will be ranked more favourably than subjects who die. 
For each of the 100 imputed datasets, the ranked scores will be compared between treatment 
groups using an ANCOVA model. The ANCOVA model will include covariates for each of the 
corresponding baseline value for the endpoint (also baseline ALSFRS-R total score for percent 
predicted SVC), baseline disease duration since symptom onset and use of riluzole or edaravone 
(as specified in Section 6.1 under Covariates). The model will be used to obtain the p-value from 
PROC MIANALYZE for the joint rank. The median change from baseline to Day 197 will be 
calculated for each of the 100 imputed datasets and these medians will be averaged across the 
100 imputed datasets. The estimates for the treatment effect will be based on the ANCOVA 
model for the change from baseline in ALSFRS-R (or SVC) as described earlier in the section 
describing MI. Estimates from the ANCOVA for ranked scores will also be presented, as 
supportive only. 
The joint rank methodology will only be performed for the mITT population. 
Adjustment for multiple testing 
The analyses of secondary endpoints will be based on a sequential testing procedure in the order 
of the rank of secondary endpoints as listed below: 
• Change from baseline (i.e. ratio) to Week 28 (Day 197) in total CSF SOD1 protein 
• Change from baseline (i.e. ratio) to Week 28 (Day 197) in NfL in plasma 
• Change from baseline to Week 28 (Day 197) in slow vital capacity (SVC). 
• Change from baseline to Week 28 (Day 197) in handheld dynamometry (HHD) 
megascore to assess muscle strength, as measured by the HHD device. 


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• Time to death or permanent ventilation, which is defined as the time to the earliest 
occurrence of one of the following events: 
− Death. 
− Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or 
noninvasive] per day for ≥ 21 consecutive days). 
• Time to death. 
 
This will control the Type I error for the secondary endpoints. If statistical significance is not 
achieved for a secondary endpoint, all secondary endpoints of a lower rank will not be 
considered statistically significant. Further details are also described in Section 6.6. 
There will be no adjustment for multiple testing for the sensitivity or supplementary analyses for 
the primary and secondary endpoints, the exploratory endpoints or subgroup analyses. 
 
6.2 Primary Efficacy Endpoint 
 
6.2.1 Primary analysis 
The primary efficacy endpoint is the change from baseline to Week 28 in the ALSFRS-R total 
score, which will be analyzed using the joint rank test (JRT) methodology to account for 
mortality [Berry 2013] for the primary inference. When implementing the JRT methodology, 
multiple imputation (MI) will be used to handle withdrawals. The estimates will be obtained 
from an ANCOVA for change from baseline in ALSFRS-R at Week 28 with missing data 
imputed using multiple imputation. The corresponding nominal p-value from the ANCOVA will 
be presented as sensitivity analysis. 
 
 
The primary analysis of the primary endpoint of Week 28/Day 197 change from baseline in 
ALSFRS-R is the composite estimand [ICH E9 (R1) Addendum 2017]. The estimand of the 
primary analysis is defined as: 
• Population: all subjects in the mITT population 
• Variable: change from baseline to Day 197 in the ALSFRS-R total score 
• Handling of intercurrent events: Relevant intercurrent events are handled using a 
composite strategy in which subjects who have these intercurrent events are ranked 
against each other and against subjects without any intercurrent event using the joint rank 
methodology based on MI imputed datasets as detailed in Section 6.1. The relevant 
intercurrent events are deaths and withdrawals. These subjects will be handled using the 


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composite strategy and ranked as above using the assessment at Day 197. For 
withdrawals this will be based on the imputed value for Day 197 from the MI datasets. 
• Summary statistics: difference between treatment groups in least square means of Day 
197 change from baseline with corresponding standard errors and 95% confidence 
intervals taken from the ANCOVA described in 6.1 based on the multiple imputation 
dataset. The ranked scores will be analyzed for each of the 100 MI complete datasets 
using an analysis of covariance model with treatment included as a fixed effect and 
adjusted for the following covariates: baseline disease duration since symptom onset , 
baseline ALSFRS-R total score, and use of riluzole or edaravone (as specified in Section 
6.1 under Covariates). The p-value for the joint rank test will be based on combining the 
estimates for the treatment differences using PROC MIANALYZE. 
In addition, median changes from baseline to Day 197 for each treatment group with 
corresponding 95% confidence intervals will be provided by treating death as worse than 
the median (i.e. assign a low value) and will be obtained for each of the 100 imputed 
datasets. The standard error will be back calculated from the 95% confidence intervals 
and used in PROC MIANALYZE to obtain a single estimate for the median and 95% 
confidence intervals. The difference between treatment groups in median changes from 
baseline to each visit will also be presented with 95% confidence intervals based on the 
multiple imputation datasets. The treatment difference for the median change from 
baseline will be obtained by determining the Hodges-Lehmann estimate for each of the 
100 imputed datasets and using PROC MIANALYZE to obtain a single estimate of the 
median treatment difference and corresponding 95% confidence intervals. 
As supportive only, least square means from the ANCOVA for rank scores will also be 
presented along with standard errors, as well as the treatment difference and 95% 
confidence intervals. The analysis will only be performed for the mITT population. 
The observed actual values and changes from baseline to each visit in ALSFRS-R total 
score will be presented. The frequency and percentage of subjects in each of Groups 1 
and 2 will also be presented. 
 
6.2.2 Sensitivity analysis of primary endpoint 
Gehan-Wilcoxon 
In addition, the treatment difference in the joint ranked scores will be compared using the 
generalized Gehan-Wilcoxon (GGW) test [Finkelstein 1999] as a sensitivity analysis of the 
primary endpoint. The T-statistic will first be calculated for the ranked scores obtained from the 
100 MI complete datasets and the corresponding p-value will be obtained from PROC 
MIANALYZE. 


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ANCOVA+MI 
MI will be applied to each of the 4 functional domain scores for ALSFRS-R separately and then 
the 100 imputed datasets for each of the domains will be used to calculate firstly the ALSFRS-R 
total score and then the change from baseline in total score. This will be calculated for each of 
the 100 imputed datasets. The change from baseline in ALSFRS-R total score for the 100 
imputed datasets will be analyzed using an ANCOVA. The MI and ANCOVA are as described 
in Section 6.1. The primary inference will be based on the treatment comparison at Day 197. For 
subjects who died or withdrew, the imputed Day 197 value will be used. Treatment differences at 
other visits will be derived from separate ANCOVA models for exploratory purposes. LS means 
and treatment differences will be presented with 95% confidence intervals and p-values at each 
visit. 
The joint rank methodology will not be used in the non mITT population as it is unlikely that 
there would be sufficient deaths in this population over the duration of Study 233AS101. 
The ANCOVA analysis based on MI datasets will also be performed for the non mITT 
population as a secondary analysis, as described in Section 6.1 and will be the main analysis for 
ALSFRS-R in this population. LS means and treatment differences will be presented with 95% 
confidence intervals and p-values at each visit. The ANCOVA analysis will also be provided for 
the Overall ITT but no p-values will be presented; the MI datasets from the non mITT and mITT 
populations will be used. LS means and LS mean changes over time will also presented in line 
plots. 
A waterfall plot will be presented for the mITT population showing the changes from baseline in 
ALSFRS-R total score to Day 197 for completers. Deaths and withdrawals will be presented 
based on observed data i.e. their last available ALSFRS-R assessment; the day of this assessment 
will be indicated on the plot. A separate waterfall plot will be presented for the non mITT 
population. 
Exclusion of deaths from MI model 
The MI model will be run for ALSFRS-R for the mITT population excluding data from any 
subjects who died, so that missing data for survivors are not influenced by any systematic 
difference there may be in data from subjects who died. The joint rank analysis will then be 
conducted using these imputed datasets for survivors and deaths will be ranked the lowest based 
on time of death. The p-value from the joint rank analysis will be presented. 


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Trimmed mean 
As a sensitivity analysis, the change from baseline in ALSFRS-R total score between treatment 
groups will be compared using the trimmed mean method to account for informative censoring 
due to death or withdrawal [Permutt and Li 2015]. This analysis will only be performed in the 
mITT population. 
 
The trimmed mean is an averaging method which eliminates a partial percentage of the smallest 
values before evaluating the standard mean of the given data. The trimmed mean difference can 
be interpreted as the mean difference of the top fraction of responses between the two groups. To 
do this, responses are ranked and subjects who have died or withdrew are considered as having 
worse outcomes than those who survived and completed the trial. To ensure that subjects who 
died or withdrew receive the lowest rank in response an arbitrary value of -999 will be assigned. 
The choice of this value does not impact the analysis results because these subjects are 
eventually excluded from the calculation of the trimmed mean statistics. Subject response scores 
in the two groups will then be ranked from the largest to the smallest separately. The top 100*p% 
response scores from the two groups will be retained and the mean response difference is 
calculated as the trimmed mean statistics. Here, p is the minimum of the proportions of subjects 
who survived and completed the assessment in the two groups. 
 
As a hypothetical example, assume at the end of the study in which 60 subjects were randomized 
and dosed, the number of subjects who died or withdrew is 3 out of 40 (7.5%) in the tofersen 100 
mg group and 5 subjects out of 20 (25%) in the placebo group. The 8 subjects who died or 
withdrew in the two groups are assigned a response score of -999. The ALSFRS-R scores at Day 
197 in the two groups are then ranked from largest to smallest separately. The top 75% of scores 
from each group will be retained and the mean difference is then calculated as the trimmed mean 
statistic. 
 
The p-value associated with the observed test statistic is then calculated using a reference 
distribution generated by the re-randomization procedure described below: 
 
1. For all 60 subjects randomized in the mITT population, randomly assign subjects in a 2:1 
ratio to treatment (tofersen 100 mg or placebo) such that there are 40 subjects in the 
tofersen 100 mg group and 20 in the placebo group. This can be done using simple 
random sampling without replacement. The seed used will be 5846894. 
2. Calculate the trimmed-mean test statistic as described above using the random treatment 
assignment in Step 1 


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3. Repeat Steps 1 and 2 N times (N=10,000). As a result, N trimmed-mean statistics will be 
generated. The empirical distribution of the N trimmed-mean statistics will then serve as 
the reference distribution for p-value calculations 
 
 
Denote the observed trimmed mean statistic as T0. Once the reference distribution has been 
established, the p-value associated with the observed test statistic is calculated as proportion of 
simulated test statistics that are either greater than |T0| or less than - |T0|. 
 
Tipping point analysis 
The tipping point analysis evaluates the impact of missing data on the reliability of treatment 
effect by varying the assumptions about the outcome of patients due to dropouts. The varying 
assumptions will include the scenarios where dropouts on tofersen 100 mg had worse future 
outcome than dropouts on placebo. The tipping region is defined as the combinations of δc and δt 
such that the treatment effect is no longer statistically significant (p-value greater than the 
significance level). The clinical plausibility of the underlying assumptions for the tipping point 
region will be discussed to evaluate the robustness of the primary findings. 
 
This tipping point analysis will follow the steps below: 
 
Step1: Missing data for placebo group and tofersen 100 mg group will be imputed using the MI 
approach described in the primary analysis 
 
Step 2: Adjust the Day 197 imputed value by adding a specified shift parameters δc and δt to 
placebo group and tofersen 100 mg group respectively 
 
Step 3: Perform the analysis and calculate the p-value for each imputed scenario, reflecting 
various degree of treatment effect about the dropouts in both groups. 
 
This analysis will be performed as 2 sensitivity analyses for: i) joint rank + MI based on primary 
efficacy analysis and ii) ANCOVA + MI. In the first sensitivity analysis, subjects will be ranked 
as per the primary efficacy analysis for each of the 100 adjusted MI datasets. The p-value for 
each shift parameter will be presented. The ANCOVA for ranked scores will be performed on 
the adjusted MI datasets, and for the second sensitivity analysis the ANCOVA will be performed 
based on the Day 197 value from the adjusted MI datasets. For each sensitivity analysis the 
results from the 100 ANCOVA analyses will then be combined using PROC MIANALYZE to 
obtain the p-value for inference. LS means, LS mean differences and corresponding 95% CI and 
p-values will be presented for each shift parameter. 


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Inclusion of baseline plasma NfL as a covariate in ANCOVA 
Given the potential utility of neurofilament as a biomarker of ALS disease activity, baseline 
plasma NfL will be added as a covariate in the ANCOVA model for the primary efficacy 
endpoint as a sensitivity analysis for the mITT population. This analysis will be performed for 
the primary efficacy endpoint, change from baseline to Day 197 in ALSFRS-R total score, based 
on both joint rank methodology as used in the primary efficacy analysis and ANCOVA based on 
MI imputed datasets. This analysis will also be performed for the non mITT population as a 
secondary analysis. 
 
 
A forest plot will present the estimate of the treatment difference and corresponding 95% CI for 
change from baseline in ALSFRS-R to Day 197 based on all the primary, secondary, 
supplementary and sensitivity analyses. 
 
6.2.3 Secondary analysis of primary endpoint 
The following secondary analyses will be performed to assess the robustness of the primary 
efficacy analysis. All the secondary analyses will be performed using the mITT population. 
Some secondary analyses may also be specified for the non mITT and overall ITT population. 
Descriptive statistics will be presented for actual values and changes from baseline in ALSFRS- 
R total score based on observed data over time for each of the mITT, non mITT and overall ITT 
populations. 
 
6.2.3.1 Joint rank test using 
permanent 
ventilation as an 
event 
As a secondary analysis, permanent ventilation (≥ 22 hours of mechanical ventilation [invasive 
or noninvasive] per day for ≥ 21 consecutive days) will also be incorporated into the joint rank 
analysis as an event. Subjects with an event of death will be ranked the lowest, where subjects 
with shortest time to death will be ranked lowest. Subjects with an event of permanent 
ventilation will be ranked higher than subjects who died but lower than all other subjects who 
completed the study or withdrew early. Within this group, subjects will be compared using their 
time to reaching permanent ventilation (as defined above) i.e. the first day of the ventilation 
period. Subjects with shortest time to permanent ventilation will be ranked lowest within this 
group. Analyses will be repeated as for the primary analysis to present the p-value from the joint 


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rank test. An event of permanent ventilation will be based on an adjudicated event (i.e. 
adjudicated by an independent committee as having met permanent ventilation based on the 
protocol-defined criteria). If a subject is adjudicated as having an event, the day of the event will 
be date of death or first date of ventilation use during the period in which the subject met the 
permanent ventilation criteria. If a subject died and reached permanent ventilation prior to this, 
the subject will be included under deaths and not permanent ventilation. 
 
6.2.3.2 Joint rank test using 
permanent 
ventilation and 
withdrawal from 
study due to disease 
progression as an 
event 
As a secondary analysis, both withdrawal from study due to disease progression and permanent 
ventilation (≥ 22 hours of mechanical ventilation [invasive or noninvasive] per day for 
≥ 21 consecutive days) will be incorporated into the joint rank analysis as separate events. 
Withdrawal from study due to disease progression will be determined from the end of study 
eCRF page where reason for withdrawal is recorded as ‘DISEASE PROGRESSION’. The 
analysis will be performed as follows: 
 
1. Deaths will all be ranked lowest based on time of death i.e. where subjects with shortest 
time from baseline (Day 1) to death will be ranked lowest 
2. Patients with an event of permanent ventilation will be ranked higher than deaths but 
lower than those who withdrew from the study for any reason and completers. Within this 
group, subjects will be compared using their time to reaching the event i.e. the first day of 
at least 21 consecutive days with at least 22 hours of ventilatory support. Subjects with 
shortest time to permanent ventilation will be ranked lowest within this group 
3. Withdrawals due to disease progression will be ranked above those subjects in 1 and 2 
above but below all other withdrawals and completers. Within this group, subjects will be 
compared using their time to reaching the event i.e. day of withdrawal (end of study day). 
Subjects with shortest time to study withdrawal due to disease progression will be ranked 
lowest within this group 
4. Completers and all other study withdrawals will be ranked highest based on Day 197 
value using MI for patients without a Day 197 value 
 
 
Analyses will be repeated as for the primary analysis to present the p-value from the joint rank 
test. An event of permanent ventilation will be based on an adjudicated event. If a subject is 


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adjudicated as having an event, the day of the event will be date of death or first date of 
ventilation use during the period in which the subject met the permanent ventilation criteria. If a 
subject reached permanent ventilation and subsequently died, this subject will be ranked with 
deaths based on their date of death rather than initiation of permanent ventilation. If a subject 
withdrew from the study for any reason and reached permanent ventilation prior to this, the 
subject will be included under the permanent ventilation group. 
 
6.2.4 Supplementary analysis of primary endpoint 
 
6.2.4.1 Japanese version of ALSFRS-R 
For eligibility assessment and primary efficacy analysis, ALSFRS-R scores for Japanese subjects 
will be assessed with a Japanese translation of the English ALSFRS-R. The English ALSFRS-R 
used in this study and the Japanese translation of the English ALSFRS-R used in the study will 
be referred to as the “Global ALSFRS-R” and “Japanese ALSFRS-R,” respectively. 
There is a version of the ALSFRS-R that has questions specifically developed for Japanese 
culture [Ohashi et al. 2001] (henceforth referred to as “Ohashi version” of the ALSFRS-R). The 
Ohashi version of the ALSFRS-R has translated Questions 1-4, 5b-10, and 12 from the original 
English-language ALSFRS-R publication [Cedarbaum 1999] into Japanese. However, Question 
5a (cutting foods and using utensils) and Question 11 (orthopnea) were modified to reflect 
Japanese culture. 
 
 
Japanese subjects will be asked to respond to Questions 5a and 11 from the Ohashi version of the 
ALSFRS-R, in addition to completing the “Japanese ALSFRS-R.” These additional questions 
will be termed the “Ohashi Version additional Questions 5a and 11” [Ohashi 2001]. 
 
 
The intention was that the Japanese ALSFRS-R would be translated directly from the Global 
ALSFRS-R. However, it was later found that the Global ALSFRS-R and Japanese ALSFRS-R 
differed. The Global ALSFRS-R is a version of the ALSFRS-R adapted from the original 
publication [Cedarbaum 1999] by Barrow Neurological Institute. This adaptation included 
updates to questions 4 (handwriting) and 11 (orthopnea) from the original wording to clarify 
answers and provide guidance on how to score these items. 
The Japanese ALSFRS-R was translated directly from the original Cedarbaum 1999 ALSFRS-R 
publication with the exception of 
• Question 11 which was translated with an error in answer 3 (“more than two” translated 
to “two or more”) (Table 10) 


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The wording of responses for each question of the ALSFRS-R is provided for each of the 
ALSFRS-R versions in Table 10, with meaningful differences highlighted. 
Table 10 Response Choices for ALSFRS-R questionnaire versions used in 233AS101 
 
 
 
Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
1.Speech 
4 Normal speech process 
Speech is as it was prior to onset of 
illness 
3 Detectable speech disturbance 
Some detectable alteration in speech 
2 Intelligible with repeating 
Some repetition is required to 
understand the speech 
1 Speech combined with non-vocal 
communication 
Gestures or communication aids are 
required to understand the speech 
0 Loss of useful speech 
Impossible for the person to 
communicate verbally 
4-Normal speech processes 
3-Detectable speech 
disturbance 
2-Intelligible with 
repeating 
1-Speech combined with 
nonvocal communication 
0-loss of useful speech 
2.Salivation 
4 Normal 
4-Normal 
3 Slight but definite excess of saliva in 
mouth; may have night time drooling 
2 Moderately excessive saliva; may 
have minimal drooling 
3-Slight but definite 
excess of saliva in mouth; 
may have nighttime 
1 Marked excess of saliva with some 
drooling 
0 Marked drooling 
Requires constant tissue or 
handkerchief 
drooling 
2-Moderately excessive 
saliva; may have minimal 
drooling 
1-Marked excess of saliva 
with some drooling 
0-Marked drooling; 
requires constant tissue 
or handkerchief 


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Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
3.Swallow- 
ing 
4 Normal eating habits 
No difficulty swallowing, can eat any 
foods/liquids of choice 
3 Early eating problems – occasional 
choking 
Ask whether patient avoids any foods 
because they get caught in his/her 
throat; can still eat all foods of choice 
but with occasional choking 
2 Dietary consistency changes 
Avoids certain foods or requires that 
consistency of foods be changed 
1 Needs supplemental tube feeding 
0 NPO 
Exclusively parental or enteral feeding 
4-Normal eating habits 
3-Early eating problems- 
occasional choking 
2-Dietary consistency 
changes 
1-Needs supplemental tube 
feeding 
0-NPO (exclusively 
parenteral or enteral 
feeding) 
4.Hand- 
4 Normal 
4-Normal 
writing 
3 Slow or sloppy: all words are 
legible 
3-Slow or sloppy; all 
words are legible 
2-Not all words are 
2 Not all words are legible 
legible 
1 No words are legible, but can still 
grip pen 
1-Able to grip pen but 
unable to write 
0-Unable to grip pen 
0 Unable to grip pen 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
5a.Cutting 
4 Normal 
4-Normal 
4 – Normal 
3 – Somewhat slow 
and clumsy, but no 
help needed 
2 – Can use a fork: 
cannot use 
chopsticks 
1 – Food must be cut 
by someone, but can 
still feed using a 
fork or a spoon 
0 – Needs to be fed 
food and 
handling 
No difficulty cutting or handling 
utensils by methods used prior to 
disease onset 
3-Somewhat slow and 
clumsy, but no help needed 
utensils 
3 Somewhat slow and clumsy, but no 2-Can cut most foods, 
without 
gastrostomy 
help needed 
Some difficulty cutting or handling 
utensils by methods used prior to 
although clumsy and slow; 
some help needed 
disease onset but patient continues to 1-Food must be cut by 
do so independently 
2 Can cut most foods (> 50%), 
although slow and clumsy; some help 
someone, but can still 
feed slowly 
needed 
0-Needs to be fed 
Some difficulty cutting or handling 
utensils by methods used prior to 
disease onset; patient requires 
assistance, but still tries to cut some 
foods, and still does >50% of the task 
successfully 
1 Food must be cut by someone, but 
can still feed slowly 
Patient cannot cut foods by methods 
used prior to disease onset, but still 
tries to feed him/herself and succeeds 
at least occasionally 
0 Needs to be fed 
5b.Cutting 
4 Normal 
4-Normal 
food and 
handling 
3 Clumsy, but able to perform all 
manipulations independently 
3-Clumsy but able to 
perform all manipulations 
utensils with 
independently 
gastrostomy 
2 Some help needed with closures 
and fasteners 
2-Some help needed with 
closures and fasteners 
1 Provides minimal assistance to 
1-Provides minimal 
caregiver 
assistance to caregiver 
0 Unable to perform any aspect of 
task 
0-Unable to perform any 
aspect of task 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
6.Dressing and 
Hygiene 
4 Normal function 
Patient has NO difficulty, and is still 
completely independent in dressing 
and hygiene by methods used prior to 
disease onset 
3 Independent; Can complete self- 
care with effort or decreased 
efficiency 
Patient still completely independent in 
dressing but requires more effort to 
dress; no substitute methods are used 
to dress 
4-Normal function 
3-Independent and complete 
self-care with effort or 
Decreased efficiency 
2-Intermittent assistance 
or substitute methods 
1-Needs attendant for 
self-care 
0-Total dependence 
2 Intermittent assistance or 
substitute methods 
Patient requires occasional assistance 
or the use of assistive devices or 
substitute methods (e.g., pull-on 
clothes, velcro closures or shoes, pre 
buttoned shirt, lying down to don 
pants) in dressing and hygiene. 
Methods used are now different than 
those used prior to disease onset 
1 Needs attendant for self-care 
Means patient needs daily caregiver 
assistance with dressing but patient has 
some level of function 
0 Total dependence 
7.Turning in 
4 Normal function 
4-Normal 
bed and 
adjusting bed 
3 Somewhat slow and clumsy, but no 
help needed 
3-Somewhat slow and clumsy 
but no help needed 
clothes 
2-Can turn alone or adjust 
2 Can turn alone, or adjust sheets, 
but with great difficulty 
sheets, but with great 
difficulty 
Patient can turn alone or adjust sheets, 
but completes task with great 
difficulty; no help needed 
1-Can initiate, but not 
turn or adjust sheets 
alone 
1 Can initiate, but not turn or adjust 
sheets alone 
0-Helpless 
0 Helpless 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
8.Walking 
4 Normal 
4-Normal 
3 Early ambulation difficulties 
3-Early ambulation 
difficulties 
Notes some difficulty, but walks 
without assistance 
2-walks with assistance 
1-Non-ambulatory 
2 Walks with assistance 
functional movement only 
0-No purposeful leg 
Includes AFO, cane, walker, or a 
caregiver 
movement 
1 Non-ambulatory functional 
movement only 
Patient is able to move lower 
extremities partially for functional 
movement; able to stand for transfers, 
but unable to walk 
0 No purposeful leg movement 
9.Climbing 
4 Normal 
4-Normal 
stairs 
3 Slow 
3-Slow 
2-Mild unsteadiness or 
2 Mild unsteadiness or fatigue 
fatigue 
Patient needs to rest between steps, or 
feels unsteady, but does not need rail 
1-Needs assistance 
0-Cannot do 
1 Needs assistance 
Patient needs assistance including 
handrail or caregiver 
0 Cannot do 
10.Dyspnea 
4 None 
4-None 
3 Occurs when walking 
3-Occurs when walking 
2-Occurs with one or more 
2 Occurs with one or more of the 
of the following: eating, 
following: eating, bathing, dressing 
bathing, dressing (ADL) 
1 Occurs at rest: difficulty breathing 
when either sitting or lying 
1-Occurs at rest, 
difficulty breathing when 
either sitting or lying 
0 Significant difficulty: considering 
using mechanical respiratory 
support 
0-Significant difficulty, 
considering using 
mechanical 
Respiratory support 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
Question 
233AS101 Global ALSFRS-R 
Non-Japanese subjects 
233AS101 Japanese ALSFRS- 
R Japanese subjects 
233AS101 Ohashi 
Version Additional 
Questions (5a and 
11) Japanese 
subjects 
11.Orthopnea 
4 None 
4-None 
4 – None 
3 – Some difficulty 
sleeping at night 
due to shortness of 
breath 
2 – Needs a 
supporting pillow in 
order to sleep 
1 – Can only sleep 
sitting up 
0 – Unable to sleep 
3 Some difficulty sleeping at night 
due to shortness of breath, does not 
3-Some difficulty sleeping 
at night due to shortness 
routinely use more than two pillows 
of breath. Does not 
routinely use two or more 
2 Needs extra pillows in order to 
sleep (more than two) 
pillows 
2-Needs extra pillow in 
1 Can only sleep sitting up 
order to sleep (two or 
more) 
0 Unable to sleep without 
mechanical assistance 
1-Can only sleep sitting 
up 
0-Unable to sleep 
12.Respiratory 4 None 
4-None 
insufficiency 
3 Intermittent use of BiPAP 
3-Intermittent use of 
BiPAP 
2 Continuous use of BiPAP during 
2-Continuous use of BiPAP 
the night 
during the night 
1 Continuous use of BiPAP during 
day & night 
1-Continuous use of BiPAP 
during the night and day 
0-Invasive mechanical 
0 Invasive mechanical ventilation by 
intubation or tracheostomy 
ventilation by intubation 
or tracheostomy 
In summary, the ALSFRS-R completed by Japanese subjects differ from the ALSFRS-R 
completed by non-Japanese subjects in two ways: 
1. The Japanese ALSFRS-R wording differs from the Global ALSFRS-R in Questions 4 and 
11. 
2. Japanese subjects also completed the Ohashi Version additional Questions 5a and 11, in 
addition to the Japanese ALSFRS-R. 
 
 
The Global and Japanese ALSFRS-Rs will be used in the primary efficacy analysis. Due to the 
differences between the Global and Japanese ALSFRS-R versions, an additional analysis will be 
performed based on the dataset used for the primary efficacy analysis, where subjects from Japan 
will be excluded from the analysis for each of the mITT and non mITT populations. This 
analysis will be performed on the primary efficacy endpoint using both the joint rank analysis 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
and ANCOVA analysis at each visit based on MI imputed datasets that were used for the primary 
efficacy analysis. 
 
To consider the effect of the Japanese culturally-specific Qusetions 5a and 11, a supplementary 
analysis will be performed by substituting the Ohashi Version additional Questions 5a and 11 for 
the Japanese ALSFRS-R Questions 5a and 11. Both the joint rank analysis and ANCOVA 
analysis based on MI imputed datasets will be performed. For all other questions, besides 
Questions 5a and 11, the responses from the Japanese ALSFRS-R questions will be used; these 
are the same as that used for the primary efficacy analysis. For subjects outside of Japan, the 
responses from the Global ALSFRS-R will be used as per the primary analysis. This analysis 
will also be performed for the non mITT population, using a ANCOVA for the MI imputed 
datasets at each visit. 
 
For Japanese subjects, a listing will also be presented to show the responses from Questions 5a 
and 11 from both the Global Japanese ALSFRS-R and the Ohashi Version additional questions 
at each visit. Any differences in responses will be flagged. The total ALSFRS-R score for 
observed data at each visit will also be included in the listing, based on each of the sets of 
responses. 
 
6.2.4.2 Exclusion of assessments by non-certified rater for ALSFRS-R 
As detailed in Section 5.5 for protocol deviations, this supplementary analysis will be performed 
if there are cases where ALSFRS-R is assessed by a non-certified rater. A supplementary 
analysis will be performed for the non mITT population by setting all values performed by the 
non-certified rater to missing and using MI to impute these values. These imputed datasets will 
be used to perform a sensitivity analysis using the ANCOVA on change from baseline in 
ALSFRS-R at Day 197. 
6.2.4.3 Exclusion of mITT subjects with percent predicted SVC <65% at baseline 
The “enriched” population is defined based on mutation and pre-randomization ALSFRS-R 
slope, but should also have percent predicted SVC ≥65% based on their screening value. It may 
be possible that some subjects have a decline in SVC between their screening assessment and 
baseline assessment, by which time their percent predicted SVC may fall below 65%. If ≥10% 
subjects in the mITT population across treatment groups have a baseline value <65% or an 
invalid assessment (i.e. “F”) at baseline for percent predicted SVC a supplementary analysis will 
be performed for the primary efficacy endpoint, change from baseline to Day 197 in ALSFRS-R 
total score, based on both joint rank methodology as used in the primary efficacy analysis and 
ANCOVA based on MI imputed datasets. The sensitivity analysis will exclude any subjects in 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
the mITT population who have percent predicted SVC <65% at baseline or all readings are 
invalid at baseline i.e. “F”. 
 
6.2.4.4 Per-protocol population 
The per-protocol population will account for treatment gaps during the loading dose period and 
subjects whose ALSFRS-R is not performed by a blinded rater, by excluding subjects who 
violated these criteria under protocol deviations. These deviations for blinded rater will be 
determined based on the protocol deviation log where standard text is entered to identify these 
cases i.e. ‘ALSFRS-R rater not blinded at Week X’. Treatment gaps during the loading dose 
period (i.e. Day 1, Day 15 or Day 29 missed doses) will be determined programmatically. The 
primary efficacy endpoint, change from baseline in ALSFRS-R total score, will be analyzed 
using this population using both joint rank methodology as in the primary efficacy analysis and 
using an ANCOVA at each visit based on MI imputed datasets. 
 
6.2.4.5 Analysis of ALSFRS-R slope of decline 
As a supplementary analysis, the slope of ALSFRS-R total scores measured from baseline to 
Day 197 will be analyzed for each of the mITT and non mITT populations. A mixed effects 
random intercept and random slope model will be used separately for each population where the 
response will be the absolute score for ALSFRS-R. The model will include baseline ALSFRS-R 
total score, baseline disease duration since symptom onset and use of riluzole or edaravone (as 
specified in Section 6.1 under Covariates) as covariates. The model will also include fixed 
effects for treatment group, time (i.e. actual time as a continuous variable), and interaction for 
treatment group by time, and a random intercept for each subject and random slope for each 
subject over time. There will be a fixed intercept for ALSFRS across all subjects. The model 
will use an unstructured covariance matrix and will be used to present LS means, standard errors 
and 95% CI for each treatment group at each visit, and LS mean differences for treatment with 
corresponding 95% CI and p-values at each visit. All postbaseline assessments (scheduled and 
unscheduled) included under 233AS101 Part C will be included in the model right through to 
end of Study 233AS101. 
In addition, as a supportive analysis, the slope of each individual subject will be derived using 
simple least square estimates (i.e. using all scores collected from baseline onwards), and 
treatment comparison using the Mann Whitney test, based on ranked data, will be made. A 
scatterplot (or boxplot) of pre-randomization slope versus post-randomization slope for each 
subject will be presented. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
6.2.4.6 Exclusion of carriers of mutations classified as “indeterminate” 
As a supplementary analysis, subjects who carry mutations adjudicated by the central lab as 
“indeterminate” (i.e. heterozygous p.Asp91Ala (D91A; D90A) mutation carriers)will be 
excluded from the analysis for the mITT population. The primary efficacy endpoint, change from 
baseline in ALSFRS-R total score, will be analyzed using this population using both joint rank 
methodology as in the primary efficacy analysis and using an ANCOVA at each visit based on 
MI imputed datasets. 
 
6.2.5 Additional analysis of primary endpoint 
 
6.2.5.1 Assessment of treatment difference for ‘enriched’ vs ‘other’ 
The primary efficacy endpoint, change from baseline in ALSFRS-R total score at Day 197, will 
be analyzed using the overall ITT population using an ANCOVA based on MI imputed datasets. 
The MI datasets from the mITT and non mITT populations will be stacked to use for this 
analysis. The ANCOVA model for each of the 100 imputed datasets will include covariates for 
baseline ALSFRS-R total score, disease progression subgroup (‘enriched’ ‘other’), baseline 
disease duration since symptom onset and use of riluzole or edaravone (as specified in Section 
6.1 under Covariates) as well as treatment group and the disease progression by treatment group 
interaction. The model will be used to present the LS mean treatment difference for each of the 
enriched and other disease progression subgroups with corresponding 95% CI, as well as the LS 
mean treatment difference and 95% CI across the subgroups. 
6.2.5.2 Subset of subjects with a slope decline ≥0.9 from screening to Day 15 
The following analyses will also be conducted: 
 
1) All subjects with an observed slope decline ≥0.9 from screening to Day 15 inclusive 
(regardless of whether they meet protocol defined ‘enriched’ or ‘other’ criteria) i.e. subset 
of Overall ITT population. The MI model for ALSFRS-R will include only data from this 
subset of subjects and will not distinguish between subjects from the ’enriched’ or ‘other’ 
population based on the protocol definition. The primary efficacy endpoint, change from 
baseline in ALSFRS-R total score at Day 197, will be analyzed for this subset of the ITT 
population based on both joint rank methodology as used in the primary efficacy analysis 
and ANCOVA based on MI . The ANCOVA model for each of the 100 imputed datasets 
will include covariates for baseline ALSFRS-R total score, baseline disease duration 
since symptom onset and use of riluzole or edaravone (as specified in Section 6.1 under 
Covariates) as well as treatment group. The model will be used to present LS means and 
standard errors for each treatment group and LS mean differences for treatment with 
corresponding 95% CI. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
2) All subjects in the predefined mITT population with an observed slope decline ≥0.9 from 
screening to Day 15 inclusive. The MI model for ALSFRS-R will include only data from 
this subset of subjects. The primary efficacy endpoint, change from baseline in ALSFRS- 
R total score at Day 197, will be analyzed for this subset of the mITT population based 
on both joint rank methodology as used in the primary efficacy analysis and ANCOVA 
based on MI . The ANCOVA model for each of the 100 imputed datasets will include 
covariates for baseline ALSFRS-R total score, baseline disease duration since symptom 
onset and use of riluzole or edaravone (as specified in Section 6.1 under Covariates) as 
well as treatment group. The model will be used to present LS means and standard errors 
for each treatment group and LS mean differences for treatment with corresponding 95% 
CI. 
 
6.3 Secondary Efficacy Endpoints 
 
6.3.1. Percent predicted SVC 
 
6.3.1.1. 
Primary analysis of percent predicted SVC 
The primary analysis for percent predicted SVC will be the joint rank method using joint rank + 
MI for the mITT population as described for the primary efficacy analysis of ALSFRS-R in 
Section 6.2.1. 
 
6.3.1.2. 
Sensitivity and secondary analysis of percent predicted SVC 
Sensitivity analysis for percent predicted SVC will be the treatment difference in the joint ranked 
scores will be compared using the generalized Gehan-Wilcoxon (GGW) test [Finkelstein 1999] 
as described for ALSFRS-R in Section 6.2.2. 
The change from baseline in percent predicted SVC will also be analyzed using an ANCOVA 
based on data imputed using MI, as described in Section 6.1. The primary inference will be 
based on the treatment comparison at Day 197. The treatment differences at each visit will also 
be presented as secondary analysis with nominal p-values. A line plot of LS means and LS mean 
changes from baseline over time will also be provided. 
 
The joint rank methodology will not be used in the non mITT population as it is unlikely that 
there would be sufficient deaths in this population over the duration of Study 233AS101. 
The ANCOVA based on MI imputed datasets will also be performed for the non mITT 
population as described in Section 6.1. LS means and treatment differences will be presented 
with 95% confidence intervals and nominal p-values at each visit. The analysis will also be 
performed for the overall ITT population but no p-values will be performed. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
The observed actual values and changes from baseline in percent predicted SVC will be 
presented at each visit for the mITT, non mITT and overall ITT populations. 
 
Supplementary analysis for change from baseline to Day 197 in percent predicted SVC will be 
performed using the Per-protocol population. The analysis will be based on both joint rank 
methodology as used in the primary analysis and ANCOVA using MI imputed datasets at each 
visit. 
A separate supplementary analysis will exclude subjects who used a facemask inconsistently at 
baseline and Day 197 (i.e. exclude if a subject used a facemask at baseline but not at Day 197 or 
if a subject did not use a facemask at baseline but used one on Day 197; also exclude if facemask 
use is unknown or missing at baseline or Day 197) . The analysis will be performed as for the 
primary analysis of this endpoint and using ANCOVA on MI imputed datasets at Day 197. 
 
 
6.3.2. HHD 
 
6.3.2.1. 
Primary analysis of HHD megascore 
The muscle strength as measured by HHD will be summarized by individual muscles and 
megascore. See Appendix B for calculation of the megascore. The normalization of individual 
muscles is performed separately for mITT and non mITT populations using the relevant baseline 
mean and standard deviation for the population. The change from baseline in HHD megascore 
will be analyzed using the ANCOVA based on MI imputed datasets as described in Section 6.1 
for the mITT population. The primary inference will be based on the treatment comparison at 
Day 197. 
 
6.3.2.2. 
Sensitivity and secondary analysis of HHD megascore 
Treatment differences at each visit will also be presented with nominal p-values. A line plot of 
LS means and LS mean changes from baseline over time will also be provided. 
The ANCOVA based on MI imputed datasets will also be performed for the non mITT 
population as described in Section 6.1. LS means and treatment differences will be presented 
with 95% confidence intervals and p-values at each visit. The ANCOVA analysis will also be 
provided for the Overall ITT but no p-values will be presented; the MI datasets from the non 
mITT and mITT populations will be used. 
The observed actual values and changes from baseline in individual muscles and HHD 
megascore will be presented at each visit for the mITT, non mITT and overall ITT populations. 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
6.3.2.3. 
Supplementary analysis of HHD 
Supplementary analysis for change from baseline to Day 197 in HHD megascore will be 
performed using the Per-protocol population. The analysis will be as for the primary analysis of 
HHD megascore i.e. the p-value and estimates at each visit will be taken from ANCOVA using 
MI imputed datasets. 
For the change from baseline to Day 197 in HHD megascore a supplementary analysis will also 
be performed on both the mITT and non mITT populations by excluding the assessments 
performed by a non-certified rater, and imputing these using MI. The ANCOVA using MI 
imputed datasets will be presented for Day 197. 
A supplementary analysis will also be performed for each of HHD upper extremities megascore 
(left and right shoulder flexion, left and right elbow flexion, left and right wrist extension, left 
and right abduction index finger, left and right abduction thumb, left and right abduction 5th 
digit) and for HHD lower extremities megascore (left and right knee extension, and left and right 
ankle dorsiflexion). The change from baseline in each of the upper and lower extremities HHD 
megascores will be analyzed using the ANCOVA based on MI imputed datasets as for the 
overall HHD megascore. These analyses will be performed at each visit for both the mITT and 
non mITT populations. Nominal p-values will be presented at each visit with LS means, 
treatment differences and 95% confidence intervals. The analysis will also be performed for the 
overall ITT population but no -p-values will be presented. 
The observed actual values and changes from baseline in upper and lower extremities HHD 
megascores will be presented at each visit for the mITT, non mITT and overall ITT populations. 
 
6.3.3. Time to death or permanent ventilation 
 
6.3.3.1. 
Primary analysis of time to death or permanent ventilation 
Time to death or permanent ventilation is defined as the time to the earliest occurrence of 1 of 
the following events: 
- 
Death. 
- 
Permanent ventilation (≥ 22 hours of mechanical ventilation [invasive or noninvasive] 
per day for ≥ 21 consecutive days). 
Endpoint Adjudication Committee (EAC) 
Time to death or permanent ventilation will be determined in a blinded fashion by a central, 
independent EAC. Procedures for reviewing and adjudicating events are described in the Charter 
that governs the operation of the EAC. As per the charter, to reach permanent ventilation, this 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
may be any combination of invasive and non-invasive ventilation as long as it occurs for the 
number of hours and days specified. 
 
Non-invasive ventilation (NIV) refers to the administration of ventilatory support without using 
an invasive artificial airway (endotracheal tube or tracheostomy tube). Modes of NIV may 
include, but not restricted to: bilateral positive airway pressure (biPAP), continuous positive 
airway pressure (CPAP), intermittent positive pressure ventilation (AVAPS), proportional-assist 
ventilation (PAV). Noninvasive ventilation can be applied including nasal and orofacial masks, 
mouthpieces, nasal pillows, total face masks, and even a helmet device. 
 
Invasive ventilation refers to the administration of ventilatory support via an endotracheal tube or 
tracheostomy tube. 
 
Ventilatory support 
 
Ventilation use during the study will be collected via the daily ventilation diary (paper or 
electronic). Other source documents in addition to the ventilation diary may be used; it is to the 
discretion of the Principal Investigator to determine the number of hours of ventilation use per 
day and the type of ventilation support used. The ventilation data from the different sources are 
entered into the ventilation log in the case report form, with the exception of the electronic diary 
data which will serve as its own source. The site should try to resolve any discrepancies between 
sources. 
 
• For example if a subject does not enter ventilation use in the diary for a period of time but 
other source documents such as hospital records indicate there was ventilation use during 
this period, the Principal Investigator is responsible for assessing and determining 
whether there was ventilation use. If there are such discrepancies the Principal 
Investigator should enter the correct data in the ventilation log which will take 
precedence over other data. 
• There were also some issues in the ediary where multiple entries for the same date were 
entered. These instances will be resolved by the Principal Investigator in review with the 
subject, and the correct entry provided in the ventilation log. 
• If a subject’s ALSFRS-R Q12 for respiratory insufficiency indicates any use of 
ventilatory support, this could be used to identify any missing gaps or discrepancies in 
the diary and completed under the ventilation log. If the subject responded 2 (Continuous 
use of BiPAP during the night) or 1 (Continuous use of BiPAP during day and night) this 
is an indicator of continuous use of ventilatory support for a period of time. The site may 
not know the number of exact hours but can enter in the ‘If Unknown, reason’ field or in 
the ‘If Yes, Please Explain’ field for ventilatory support that the source used was 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
ALSFRS-R (based on the response and interaction with the subject on completion of 
ALSFRS-R) and additionally whether it was continuous use during day per day and 
night. If the record does not specify exact number of hours but the site comment indicates 
that they used ALSFRS-R as a source the entry will be mapped to the corresponding 
response on ALSFRS-R. If the subject had continuous use of BiPAP during the night it 
will be assumed that this is 8 hours for the purpose of supplementary analysis; if it 
indicates that subject responded as continuous use of BiPAP during the day and night for 
analysis purpose it will be assumed that this is 22 hours. This determination will be made 
only for the supplementary analysis of time to death or permanent ventilation and for the 
profile plots and summaries; not for the primary analysis using adjudicated events. A 
programmatic search in the comments fields of the ventilation log will be applied to look 
for ALSFRS-R. 
 
Analysis 
The analysis is to compare the time to death or permanent ventilation between the treatment 
groups in the mITT population using the log-rank test stratified by riluzole or edaravone use (as 
specified in Section 6.1 under Covariates). Only events that were adjudicated by the EAC as 
meeting the protocol defined criteria for permanent ventilation or death will be included in the 
primary analysis. Subjects who do not meet the endpoint definition will be censored on the 
subject’s last contact in Study 233AS101. Follow-up will end on the last occasion that the 
subject was seen in the 233AS101 study (either as an in-person visit or by home visit or by 
telephone contact). This is regardless of whether the subject completed their full course of 
treatment, whether the subject completed the study or withdrew prematurely. 
 
Kaplan-Meier estimates of the cumulative probability of the time to death or permanent 
ventilation over time will be determined for the mITT population. Treatment comparison of time 
to death or permanent ventilation will be based on a stratified log rank test. Stratification factors 
will be riluzole or edaravone use (as specified in Section 6.1 under Covariates). Kaplan-Meier 
plots will be presented. The median time to death or permanent ventilation, percentiles (5th, 10th, 
25th, 75th) and associated 95% confidence limits, and proportion of subjects who meet an event 
by Day 197 will be estimated using the Kaplan-Meier. A Cox proportional hazards model will be 
used to obtain the hazard ratio and 95% confidence intervals. The Cox proportional hazards 
model will adjust for baseline disease duration since symptom onset, baseline ALSFRS-R total 
score, and riluzole or edaravone use (as specified in Section 6.1 under Covariates). 
 
The start date for calculating time to death or permanent ventilation in days i.e. death, permanent 
ventilation or censoring will be date of first dose. If a subject is adjudicated as having an event, 


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Statistical Analysis Plan 
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the day of the event will be date of death or first date of ventilation use during the period in 
which the subject met the permanent ventilation criteria. 
 
The proportion of subjects meeting the endpoint, time to death or permanent ventilation, will be 
presented by treatment group. For subjects who met the endpoint, time to death or permanent 
ventilation, the number of days per subject at which ventilation use was at least 22 hours per day 
will be summarized. 
 
6.3.3.2. 
Sensitivity and secondary analysis of time to death or permanent 
ventilation 
As a secondary analysis the analysis specified in Section 6.3.3.1 for the mITT population will be 
repeated for the non mITT population and the Overall ITT population. No p-values will be 
presented for the Overall ITT population. 
 
6.3.3.3. 
Supplementary analysis of time to death or mechanical ventilation 
Two sets of supplementary analyses for time to death or permanent ventilation will also be 
analyzed using the following definitions based on ventilation data in the log and ediary records 
from the clinical database and not the adjudicated events: 
 
1) Time to the earliest occurrence of 1 of the following events: 
- 
Death. 
- 
Mechanical ventilation for ≥ 22 hours of mechanical ventilation [invasive or noninvasive] 
per day for ≥ 7 consecutive days. 
2) Time to the earliest occurrence of 1 of the following events: 
- 
Death. 
- 
Mechanical ventilation for ≥ 22 hours of mechanical ventilation [invasive or noninvasive] 
per day for ≥ 21 consecutive days. 
Events for mechanical ventilation will be determined using the number of hours specified in the 
ediary or ventilation log. As detailed in 6.3.3.1, if exact number of hours are not specified and 
the comment in the ventilation log indicates that ALSFRS-R was used as a source then 
depending on the response 8 hours will be imputed only for those specific records if the subject 
used BiPAP continuously at night (a score of “2” on the respiratory insufficiency domain of the 
ALSFRS-R at the visit corresponding to the diary/log entries) and 22 hours will be imputed if the 
subject used BiPAP continuously during day and night (a score of “1” on the respiratory 
insufficiency domain of the ALSFRS-R at the visit corresponding to the diary/log entries). The 
number of hours will not be imputed if the ALSFRS-R score was anything other than 1 or 2; if 
number of hours is specified and in addition the source indicates ALSFRS-R there will be no 


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imputation as number of hours recorded in the ediary or vent log will take precedence. If there 
are ventilation records indicating vent use and there are no hours entered and ALSFRS-R was 
not specified as a source the number of hours will not be imputed. 
 
The analysis will be performed for both the mITT, non mITT and Overall ITT population. 
Subjects who do not meet the endpoint definition will be censored on the subject’s last contact in 
Study 233AS101. Follow-up will end on the last occasion that the subject was seen in the 
233AS101 study (either as an in-person visit or by home visit or by telephone contact). This is 
regardless of whether the subject completed their full course of treatment, whether the subject 
completed the study or withdrew prematurely. 
 
Kaplan-Meier estimates of the cumulative probability of the time to death or permanent 
ventilation over time and Cox proportional hazards model will be performed as specified for the 
primary analysis in Section 6.3.3.1. 
 
The start date for calculating time to death or permanent ventilation in days i.e. death, permanent 
ventilation or censoring will be date of first dose. The day of the event will be date of death or 
first date of ventilation use during the period in which the subject met the permanent ventilation 
criteria. The proportion of subjects meeting the endpoint, time to death or permanent ventilation, 
will be presented by treatment group. For subjects who met the endpoint, time to death or 
permanent ventilation, the number of days per subject at which ventilation use was at least 22 
hours per day will be summarized. For each of the mITT and non mITT populations, the 
following will also be presented: 
 
• Proportion of subjects using any vent support at Week 28 (or last available assessment for 
withdrawals and deaths) as recorded on the vent log 
• Proportion of subjects with invasive mechanical ventilation recorded at Week 28 (or last 
available assessment for withdrawals and deaths) as per the ALSFRS-R Question 12 (i.e. 
score of 0) on respiratory insufficiency. 
 
For subjects in the mITT and non mITT populations with any ventilation data recorded (i.e. >0 
hours of vent use on at least 1 day), patient profile plots (lollipop plots) will be presented 
showing the number of hours of ventilation use by study day. Imputed hours will also be 
represented if exact number of hours were not specified and ALSFRS-R was used as a source 
based on the response i.e. 8 hours will be imputed if the subject used BiPAP continuously at 
night and 22 hours will be imputed if the subject used BiPAP continuously during days and 
night. If there are ventilation records indicating vent use and there are no hours entered and 
ALSFRS-R was not used as a source the number of hours will not be imputed. Imputed flags will 
be denoted on the plot and explained in a footnote. 










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Statistical Analysis Plan 
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6.5 Subgroup Analysis 
Subgroup analysis will be performed for the primary efficacy endpoint and for the following 
secondary endpoints: change from baseline in percent predicted SVC, change from baseline in 
HHD megascore, and ratio to baseline for each of total CSF SOD1 protein and plasma NfL for 
each of the mITT, non mITT and ITT populations. Descriptive statistics for observed data will be 
presented by treatment group and each of the subgroup categories. 
• Gender (female, male) 


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• Baseline disease duration since symptom onset by tertiles (tertiles to be defined 
separately for each of mITT, non mITT and overall ITT) (median values may be used 
instead of tertiles if insufficient data) 
• Baseline NfL plasma level (tertiles to be defined separately for each of mITT, non mITT 
and overall ITT) (median values may be used instead of tertiles if insufficient data) 
• Site of onset (bulbar, other site of onset). If a subject had onset at multiple sites and one 
of the sites is bulbar the subject will be included under the bulbar category for subgroup 
analysis. 
• Geographic region (North America, Europe, Asia Pacific) – Canada will be included 
under North America 
• Riluzole or edaravone use (Note: If Edaravone use is limited to <5 subjects within the 
relevant population (e.g. mITT) then riluzole and edaravone use will be combined so that 
there are only 2 levels) 
 
For the mITT, non mITT populations and the ITT population, each subgroup category will also 
be analyzed separately using the ANCOVA based on MI. For the overall ITT population, no p- 
values will be presented. 
The 100 imputed datasets will be analysed using an ANCOVA for each subgroup category 
including baseline value, riluzole/edaravone use, treatment and baseline disease duration. The 
ANCOVA will not include baseline disease duration if that is the subgroup being analysed. 
Similarly, use of riluzole or edaravone will not be included as a covariate if that is the subgroup 
being analysed. If the ANCOVA analysis uses riluzole/edaravone use as a 3 level covariate and 
the model does not converge, then rilzuole/edaravone may be included as a 2 level covariate for 
that specific subgroup analysis. Any subgroup category that has an insufficient number of 
subjects for the ANCOVA analysis to be generated for that category will not be presented, but 
other categories for the subgroup will still be presented 
An analysis will also be performed for the mITT population on the subgroup of subjects with a 
pre-randomization ALSFRS-R slope decline of at least 0.9 per month. This analysis will be 
performed for each of the 5 endpoints mentioned above. The MI model for each endpoint will be 
performed in this subset of subjects prior to running the analysis. Both the ANCOVA using MI 
and joint rank methodology will be performed for ALSFRS-R and percent predicted SVC. For 
the other endpoints, ANCOVA using MI will be presented. 


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Statistical Analysis Plan 
Version No.: Final V2.0 
 
6.6 Statistical Testing Procedure 
The primary endpoint and secondary endpoints will all be tested sequentially at the two-sided 
alpha of 0.05 for the final analysis after all subjects have completed the study and final database 
has locked. There will be no interim analysis. 
Below is a description of the sequential testing procedure for secondary endpoints if the primary 
endpoint is statistically significant at an alpha of 0.05. 
• The change from baseline (i.e. ratio) to Week 28/Day 197 in total CSF SOD1 protein will 
be tested at an alpha of 0.05. If it is statistically significant then proceed to the next step; 
otherwise all subsequent tests are considered exploratory. 
• The change from baseline (i.e. ratio) to Week 28/Day 197 in plasma NfL will be tested at 
an alpha of 0.05. If it is statistically significant then proceed to the next step; otherwise all 
subsequent tests are considered exploratory. 
• The change from baseline to Week 28/Day 197 in SVC will be tested at an alpha of 0.05. 
If it is statistically significant then proceed to the next step; otherwise all subsequent tests 
are considered exploratory. 
• Test change from baseline to Week 28/Day 197 in HHD megascore at an alpha of 0.05. If 
it is statistically significant then proceed to the next step; otherwise all subsequent tests 
are considered exploratory. 
• Test time to death or permanent ventilation at an alpha of 0.05. If it is statistically 
significant then proceed to the next step; otherwise all subsequent tests are considered 
exploratory. 
• Test time to death at an alpha of 0.05. 
If the primary efficacy endpoint is not statistically significant at the final analysis, then the 
testing of the secondary endpoints will be considered exploratory. 
Table 11 summarizes the analysis sets, populations and testing that would be performed. 


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Statistical Analysis Plan 
Version No.: Final V2.0 
 
Table 11 Analysis sets and populations for final analysis 
 
mITT 
non mITT 
Overall ITT 
Demographics/baseline 
disease history; drug 
exposure/compliance 
X 
X 
X 
Primary efficacy 
endpoint 
Formal testing 
Descriptive and 
estimates with 
confidence 
intervals and 
nominal p-values 
Descriptive and 
estimates with 
confidence intervals 
Total CSF SOD1 
protein 
Formal testing 
only if primary 
efficacy 
endpoint is 
statistically 
significant 
(otherwise 
exploratory) 
Formal testing 
Descriptive and 
estimates with 
confidence intervals 
and nominal p-values 
Plasma NfL 
Formal testing 
only if primary 
efficacy 
endpoint is 
statistically 
significant 
(otherwise 
exploratory) 
Descriptive and 
estimates with 
confidence 
intervals and 
nominal p-values 
Descriptive and 
estimates with 
confidence intervals 
Secondary efficacy 
endpoints 
Formal testing 
only if primary 
efficacy 
endpoint is 
statistically 
significant 
Descriptive and 
estimates with 
confidence 
intervals and 
nominal p-values 
Descriptive and 
estimates with 
confidence intervals 


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Statistical Analysis Plan 
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(otherwise 
exploratory) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
8. Pharmacodynamic Data 
All summaries and analyses of PD/biomarker data will be presented for each of the mITT and 
non mITT populations. In addition, analyses of total CSF SOD1 protein will be presented for the 
overall ITT population as exploratory analysis. 
The following PD/biomarker endpoints will be summarized: 
 
 
neurofilament light chain (NfL) will be analyzed in plasma. 
• Total SOD1 protein will be analyzed in the CSF. In the Phase 1 (233AS101 Part B) 
study, total CSF SOD1 protein was reduced in tofersen-treated participants, irrespective 
of their rapidity of disease progression. As such, total CSF SOD1 protein serves as a 
bridging marker of treatment effect for the non-mITT population in which differentiation 
from placebo on clinical outcome measures may not be apparent over the 6 month 
treatment period. 
CSF NfL, misfolded or mutant SOD1 and Urinary p75ECD may also be summarized and analyzed 
depending on the timing of the assay availability. These are unlikely to be available at the time of 
the readout following database lock, and therefore depending on timing may be included as part 
of an addendum to the CSR. 
Due to technical platform variability observed in other datasets, select neurofilament samples 
may be re-tested post-hoc (after database lock) in case of any extreme outliers. 
Values that are BLQ will be set to half of LLOQ (15.6 ng/mL for total CSF SOD1 protein, 
 
CSF and plasma, 17.4 pg/mL for NfL in CSF and 0.696 pg/mL for NfL in 
plasma). 
Testing of total CSF SOD1 protein and plasma NfL endpoints is discussed in Section 6.6 as part 
of the secondary endpoint testing. 


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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
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MI for imputation 
A summary of missing data for each PD/biomarker endpoint will be presented. 
For each of the PD/biomarker endpoints, any missing postbaseline will be imputed. Baseline will 
not be imputed. 
The primary analysis will use MI to impute all missing values. The MI model will be performed 
based on log transformed data for each PD/biomarker endpoint using the methods described in 
Section 6.1. There will be no resetting of imputed values. The seed used for each PD/biomarker 
endpoint is given in Table 12. The model will be performed by population (i.e. for mITT and non 
mITT). Before running the model the dataset will be sorted by population (mITT first), and by 
USUBJID. 
Table 12: Seed used for each PD/biomarker endpoint in MI 
 
Endpoint 
Seed 
Total SOD1 protein in CSF 
1327538 
 
 
 
 
 
 
NfL in plasma 
4311930 
A sensitivity analysis will use LOCF to impute missing Day 197 values, using Day 169 value if 
available (see Section 6.1). Otherwise MI will be used to impute missing values at all other 
visits. 
Analysis 
An ANCOVA model for log ratio to baseline for each of the mITT and non mITT populations 
will be performed on change from baseline values on log scale ((i.e. log(postbaseline) – 
log(baseline)) for each of the 100 imputed datasets for each PD/biomarker endpoint. The model 
will include covariates for the corresponding baseline value i.e. log value, baseline disease 
duration since symptom onset, and use of riluzole or edaravone (as specified in Section 6.1 under 
Covariates). A separate ANCOVA model will be run on total CSF SOD1 protein and plasma 
NfL for the overall ITT population based on the MI models run on each of the mITT and non 
mITT populations. The ANCOVA model will be as described. 
The least square (LS) i.e. adjusted mean of each treatment group, as well as the treatment group 
differences will be presented with 95% confidence intervals (CI) and the p-value. 
Presentations of data 


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Descriptive statistics of actual values and absolute changes from baseline for each PD/biomarker 
endpoint at each visit and ratio to baseline will be summarized by treatment group. The summary 
statistics will include arithmetic mean and SD for the ratio to baseline as well as the geometric 
mean ratio and corresponding standard error. The geometric mean ratio will be obtained by back- 
transforming change from baseline on log transformed data. Arithmetic means and geometric 
means will be presented for the actual values and absolute changes from baseline at each visit. 
The descriptive summaries will be presented for each of the mITT, non mITT and overall ITT 
populations. Descriptive statistics of actual values, absolute changes from baseline and ratio to 
baseline will be presented using observed data. 
 
 
A plot of the geometric mean and standard deviation for the actual values over time will be 
presented based on observed data. 
Listings of individual data will also be provided. 
The treatment difference at Day 197 will be derived from the model and back-transformed to the 
original scale. Treatment differences at other visits will also be derived from the model for 
exploratory purposes. For each PD/biomarker endpoint least-squares (LS) means for each 
treatment group each visit as well as the treatment differences at each visit will be presented, 
along with 95% CI and p-values. The back-transformed LS means here represent geometric 
mean ratios compared to baseline, and the back-transformed LS means differences represent 
geometric mean ratios of the ratios compared to baseline between tofersen 100 mg and placebo. 
These geometric mean ratios will also be plotted. 
The ANCOVA will be performed for both the mITT population and non mITT population as 
described in Section 6.1. For total CSF SOD1 protein and plasma NfL the ANCOVA will also be 
performed for the overall ITT population. LS means and treatment differences will be presented 
with 95% confidence intervals and p-values at each visit (no p-values will be presented in the 
Overall ITT for plasma NfL). Subgroup analyses as specified in Section 6.5 will also be 
presented for CSF SOD1 and plasma NfL; these also include an analysis for the mITT 
population on the subgroup of subjects with a pre-randomization ALSFRS-R slope decline of at 
least 0.9 per month. 


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9. Safety Data 
The safety population will be used for the analyses of the safety data. All summaries of AEs and 
CSF laboratory parameters will also be presented by population (“enriched” “other”). Safety data 
will be summarized using frequency counts and percentages and descriptive statistics by 
treatment group. 
A summary of missing safety data by visit and overall (i.e. C-SSRS, laboratory data broken 
down by panel, vital signs, ECG, neurological exam, MMSE) will be presented. The summary 
will also be broken down by whether the visit was missed due to COVID-19 or other reason. 
 
9.1 Adverse Events 
All AEs will be classified using MedDRA version 24.0. All AEs will be listed but only 
treatment emergent AEs will be summarized, where treatment emergence will be relative to the 
first dose of study drug. A treatment emergent AE/SAE is defined as any AE/SAE with an onset 
date and time that is on or after the first dose of study drug or any pre-existing condition that has 
worsened in severity after the first dose of study drug. In case of missing dates, 
• any AE/SAE with both a missing onset date and resolution date, or any AE/SAE with a 
missing onset date and a resolution date which is after the first dose of study drug, will be 
considered treatment emergent. 
• If the onset date is available but onset time is missing and the AE onset date is the same 
as the first dose date the AE will be considered treatment emergent. 
• For AEs with a partial start date, the year/month of the event date will be compared to 
that of the first dose date to determine whether the event is treatment emergent. 
 
The incidence of treatment emergent AEs will be summarized by treatment group as follows 
(these summaries will be presented overall and by population (“enriched” “other”)): 
• by primary system organ class (SOC) and MedDRA preferred term sorted by decreasing 
frequency 
• by SOC and MedDRA preferred term sorted by alphabetical order 
• by MedDRA preferred term 
• by SOC 
• The most common treatment emergent AEs i.e. occurring in 3 or more subjects in any 
treatment group will be presented by MedDRA preferred term. 


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• The most common treatment emergent AEs i.e. occurring in 2 or more subjects in any 
active treatment group compared to placebo will be presented by MedDRA preferred 
term. 
• by maximum CTCAE grade, primary SOC and MedDRA preferred term 
• by maximum CTCAE grade and MedDRA preferred term 
• AEs with a CTCAE grade>=3 by primary SOC and MedDRA preferred term 
• related AEs by primary SOC and MedDRA preferred term 
• SAEs by primary SOC and MedDRA preferred term 
• SAEs by MedDRA preferred term 
• Related SAEs by primary SOC and MedDRA preferred term 
• AEs related to lumbar puncture (as assessed by the investigator) by primary SOC and 
MedDRA preferred term 
• AEs that occurred within 24 hours of dosing by primary SOC and MedDRA preferred 
term (in case of partial AE start date, if the month and year are available and day is 
missing, the AE will be included for any dose that occurs in the same month and year as 
the AE) 
• AEs led to discontinuation of study drug by primary SOC and MedDRA preferred term 
• AEs led to withdrawal from study by primary SOC and MedDRA preferred term 
• AEs led to drug interrupted by primary SOC and MedDRA preferred term 
• AEs led to hospitalization by primary SOC and MedDRA preferred term (showing 
number and percentage of subjects with at least one occurrence in that SOC or preferred 
term, as well as total number of events). Further summaries of hospitalization data are 
also included later in this section. 
• AEs that led to death 
• AEs of note (serious neurologic events, falls, CSF laboratory abnormalities) for which 
preferred terms will be based on a medical review before final analysis and unblinding. 
This summary will include number and percentage of subjects with at least one event 
and total number of events. The follow-up adjusted incidence rates based on number of 
subjects as well as number of events will also be presented in the same table. See 
calculation later in this section on incidence rates. If any of these are defined based on 
more than one preferred term, the preferred terms will also be broken down under the 
overall category. 


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The sorting order for AE incidence tables, unless otherwise specified, will be by decreasing 
frequency order of “tofersen 100 mg” column. For the AE summary by primary system organ 
class and preferred term, subjects will be counted only once within each primary SOC/MedDRA 
preferred term. For the summary of AEs by maximum CTCAE grade, primary system organ 
class and preferred term, subjects will be counted only once within each primary SOC/MedDRA 
preferred term and will only be counted under the maximum CTCAE grade. For the summary of 
related AEs, if the relationship is missing then this will be summarized as unknown. 
For AEs that occurred within 24 hours of dosing, if time of AE is missing and the event occurs 
on the same day as the day for dosing or the day following dosing, the AE will be counted as 
occurring within 24 hours of dosing. 
An overall summary of AEs will also be presented. A separate table will also be presented to 
show an overall summary of COVID-19 pandemic related AEs. 
Listings of the following events will be produced. 
 
• AEs led to discontinuation of study drug 
• AEs led to withdrawal from study 
• AEs led to drug interrupted 
• AEs related to lumbar puncture 
• AEs led to hospitalization 
• SAEs 
• AEs 
 
A listing of deaths will be provided if applicable. 
 
An additional table for hospitalizations will present the number and percentage of subjects in 
each treatment group with at least one hospitalization, the number of hospitalizations per subject, 
total number of hospitalizations, and a descriptive summary for the total cumulative duration of 
hospitalizations per subject. 
Pre-treatment SAEs, i.e. those that occurred between screening and first dose are not considered 
treatment emergent, and will be summarized separately if there are a sufficient number. Pre- 
treatment AEs should not be collected unless classed as serious. It is likely that there may be a 
few non-serious AEs related to study procedures (e.g. lumbar puncture) that occurred on the 
same date as first dose but prior to the start time of dosing. These AEs will be summarized 


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separately. All SAEs will be listed, with an indicator for pretreatment SAEs. Only treatment 
emergent AEs will be summarized, unless otherwise specified. 
A separate summary will be presented for each of confirmed COVID-19 AEs and suspected 
COVID-19 AEs. These will be identified as AEs that are recorded with an entry of ‘(Confirmed)’ 
and ‘(Suspected)’. As per the guidance, confirmed cases are those confirmed via a diagnostic test 
and suspected cases are those diagnosed based on typical symptoms, travel/contact history. A 
listing will also be provided. 
Incidence rate tables 
 
Incidence and incidence rate will be provided in incidence rate tables and will be summarized by 
primary SOC and MedDRA preferred term by treatment group. Two different kinds of incidence 
rate tables will be provided. Definitions are provided below: 
(1) Follow-up adjusted incidence rate – defined as the number of subjects who experienced 
an event divided by the total of entire follow-up time among the subjects in the analysis 
population. The entire follow-up time for subject is defined as the time from the first dose 
until the last day on study. Each subject will be counted only once within each category. 
A similar table will also be based on total number of events divided by the total of entire 
follow-up time among the subjects in the analysis population. This may count a subject 
more than once within each category of they experienced an event more than once. 
 
(2) Exposure-adjusted incidence rate (EAIR) – defined as the number of subjects who 
experience an event divided by the total exposure adjusted follow-up time among the 
subjects in the analysis population. The exposure adjusted follow-up time is defined as 
the time from the first dose until the initial occurrence of the event for those who 
experienced an event, or from the first dose until the end of follow-up (the last day on 
study) for those who did not. Each subject will be counted only once within each 
category. If the initial occurrence of the event has a partial start date, the following rules 
will be applied. If only month and year of the AE are available, and the month and year 
are same as that of the first dose then it will be assumed that the event started on date of 
first dose. Otherwise it will be assumed that the event started on the first of the month. If 
only year is available, and the year is same as that of the first dose then it will be assumed 
that the event started on the date of first dose. Otherwise it will be assumed that it started 
on the 1st January. 


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Statistical Analysis Plan 
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9.2 Laboratory Data 
Laboratory data will be evaluated to determine the incidence of abnormalities that emerge during 
the course of the study. Changes in laboratory evaluations will be presented relative to baseline, 
which is defined as the closest visit prior to the subject starting treatment. 
The following clinical laboratory parameters are assessed in the protocol: 
• Hematology panel: complete blood count with differential and platelet count (hematocrit, 
hemoglobin, platelets, red blood cell count [RBC], white blood cell count [WBC], 
basophils, eosinophils, lymphocytes, monocytes, neutrophils) 
• Blood chemistry panel: albumin, total bilirubin, direct bilirubin, alkaline phosphatase, 
alanine aminotransferase (ALT) (SGPT), aspartate aminotransferase (AST) (SGOT), 
gamma-glutamyl transferase (GGT), sodium, potassium, calcium, chloride, phosphate, 
blood urea nitrogen (BUN), creatinine, uric acid, bicarbonate (CO2), glucose, total 
protein. 
• Urinalysis: blood, glucose, protein, and microscopic examination if abnormal 
• CSF analysis: RBC, WBC, protein, glucose. 
• Coagulation: PT (prothrombin time), aPTT (activated partial thromboplastin time), and 
INR (international normalized ratio). 
If multiple samples are collected at the same visit, the samples collected at the earliest time will 
be analyzed after applying visit window rules as described in Section 4.3. For CSF laboratory 
parameters, tube 2 results will be analyzed if available. 
Baseline value is defined as data collected which are prior to and/or on the date of the first dose, 
usually also the same day as the Day 1 visit. If there is more than one value on or before Day 1, 
then the last non-missing value prior to (including on) the date of first dose will be used as the 
baseline value. 
 
Each hematology, blood chemistry, coagulation and CSF laboratory parameter will be flagged as 
“low” or “high” relative to the parameter’s normal range or as “unknown” if no result is 
available. For each urinalysis laboratory parameter, the number and percentage of subjects 
experiencing post-dosing shifts to abnormal will be summarized. For each hematology, blood 
chemistry, coagulation and CSF parameter, the number and percentage of subjects experiencing 
post-dosing shifts to ‘low’ or ‘high’ will be summarized. In each summary, the denominator for 
the percentage is the number of subjects at risk for the shift. The number at risk for the shift to 
low is the number of subjects whose baseline value was not low and who had at least one 
postbaseline value.  The number at risk for the shift to high is the number of subjects whose 


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baseline value was not high and who had at least one-post baseline value. Subjects will be 
counted only once for each parameter and each shift regardless of how many post-dosing 
assessments had that type of shift. Subjects with shift will be listed by laboratory parameter and 
shift type. All postbaseline data will be used in the shift tables, regardless of whether a scheduled 
or unscheduled visit. For CSF laboratory parameters, both tubes will be used in this assessment 
for the shift tables. 
Summary statistics for actual values and change from baseline in laboratory values will be 
summarized by treatment group and visit. Line plots for chemistry, hematology and CSF 
showing mean value for each treatment group at each visit will also be presented. 
To evaluate potential serious hepatotoxicity subjects with a postbaseline AST and/or ALT value 
≥3 times the upper limit of normal (ULN) and a postbaseline bilirubin value >2 times ULN at 
any time, not necessarily concurrent, will be listed with their values. In addition, a plot will be 
presented with each subject’s maximum postbaseline AST or ALT value relative to the ULN 
against the subject’s maximum postbaseline bilirubin value relative to the ULN; values do not 
have to be concurrent. All postbaseline data will be used to identify abnormalities, regardless of 
whether a scheduled or unscheduled visit. 
Listings of all chemistry, hematology, coagulation, CSF, urinalysis values and pregnancy test 
(serum and urine) will be provided. Abnormal values and potentially clinically significant values 
will be flagged. 
 
Subjects with at least one postbaseline CSF WBC values >5 will have their CSF WBC plotted 
over time in a spaghetti plot. A separate plot will also be presented for any subjects who have a 
postbaseline CSF WBC value >10. Corresponding listings will also be presented with AEs that 
occurred at any time on or after the subject had a postbaseline CSF WBC value >5 and any time 
on or after the subject had a postbaseline CSF WBC value >10. A summary table will also 
present number and percentage of subjects with at least one postbaseline CSF leukocyte >5 and 
number and percentage with at least one postbaseline CSF leukocyte >10. The summary will also 
present total number and percentage of individual values >5 and total number and percentage of 
individual values >10. All postbaseline data will be used in this summary, regardless of whether 
a scheduled or unscheduled visit. 
 
A summary table and listing of lumbar puncture and CSF sample collection data other than CSF 
laboratory results (i.e. lumbar puncture position, number of attempts, interspaces, additional 
guidance used, CSF volume collected, needle and gauge information) will also be provided. 


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9.3 Vital Signs 
Summary statistics for actual values and change from baseline will be presented for each vital 
sign parameter (temperature, weight, pulse, respiration, systolic and diastolic blood pressure) by 
treatment group and visit. A listing of vital sign data will also be provided. 
Vital signs (temperature, pulse, systolic and diastolic blood pressure) will also be examined to 
determine the incidence of potentially clinically relevant abnormalities.  The number of subjects 
evaluated and the number of subjects with potentially clinically relevant abnormalities will be 
presented. All postbaseline data will be used to identify abnormalities, regardless of whether a 
scheduled or unscheduled visit. The criteria for potentially clinically relevant post-dosing 
abnormalities are shown in Table 13 below: 
Table 13: Criteria to determine potentially clinically relevant abnormalities in vital signs 
 
Vital Sign 
Criteria for Abnormalities 
Temperature 
<36°C 
>38°C 
Pulse 
>100 beats per minute (bpm) <60 bpm 
Systolic Blood Pressure 
<90 mmHg 
>140 mmHg 
>160 mmHg 
Diastolic Blood Pressure 
<50 mmHg 
>90 mmHg 
>100 mmHg 
Weight 
7% or more increase from baseline 
7% or more decrease from baseline 
Respiratory Rate 
<12 
>20 


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9.4 ECG 
The ECG test includes heart rate, PR interval, QRS interval, QT interval, QTc interval using 
Bazett’s formula, QTc interval using Fridericia’s formula, and RR interval. Summary statistics 
for actual values and change from baseline in each ECG parameter will be presented by 
treatment group and visit. 
The number and percentage of subjects with shifts from normal to each of the categorical values 
denoting an abnormal scan (abnormal not AE, abnormal AE) will be summarized by treatment 
group. All postbaseline data will be used to identify abnormalities, regardless of whether a 
scheduled or unscheduled visit. A listing of subjects with abnormal status in ECG will be 
presented. 
QTc (interval using Fridericia’s formula) will also be examined to determine the incidence of 
clinically relevant abnormalities. The number of subjects evaluated and the number of subjects 
with clinically relevant abnormalities will be presented. The criteria for clinically relevant post- 
dosing abnormalities are: 
• Maximum increase from baseline QTcF > 30 to 60 ms 
• Maximum increase from baseline QTcF > 60 ms 
• Maximum postbaseline QTcF > 480 to 500 ms 
• Maximum postbaseline QTcF > 500 ms 
 
9.5 Mini-Mental State Exam (MMSE) 
Summary statistics for actual values and change from baseline of the total score of MMSE will 
be presented for each visit by treatment group. When there are multiple assessments during a 
single visit, the minimal value will be taken as the value for that visit. A listing of MMSE data 
for individual patients will also be provided. 
 
9.6 Limited neurological examinations 
The number and percentages of the status in each assessment of coordination/cerebellar function 
and each assessment of reflexes will be summarized by treatment group and visit. The reflexes 
neurological examination of upper and lower extremities will be analyzed as continuous 
variables (0 = absent, 1 = trace, 2 = normal, 3 = brisk, 4 = clonus). The descriptive statistics will 
be summarized by treatment group and visit. Stacked bar charts showing the proportion of 
subjects in each response category in each treatment group over time will be generated to show 
shifts over time. 
The motor neurological examination will be analyzed as continuous variable (0 = no contraction 
or can’t position limb; 1 = flicker or trace contraction, no movement; 2 = movement only with 


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gravity eliminated; 3 = movement against gravity; 4 = movement against gravity and resistance; 
5 = normal strength). Summary statistics will be presented by treatment group and visit. Stacked 
bar charts showing the proportion of subjects in each response category in each treatment group 
over time will be generated to show shifts over time. 
Baseline values will be taken from Day 1 predose unless an entire section of the neurological 
exam (i.e. coordination/cerebellar function, reflexes, motor) is missing or not done, in which case 
for that specific section baseline will be taken from the Screening visit for all items within that 
section of the exam. 
Listings will also be provided with complete details for the neurological examinations. 
 
9.7 Columbia Suicide Severity Rating Scale (C-SSRS) 
The details of derivation and imputation for C-SSRS is described in Appendix D. The following 
analyses on C-SSRS measurements will be conducted: 
• Descriptive summary of subjects who answered “Yes” to any question 1-12 as well as 
subjects who had suicidal ideation or suicidal behavior at baseline and at any postbaseline 
visit. The denominator for baseline summary is the number of subjects who were dosed 
and had baseline assessment; the denominator for postbaseline summary is the number of 
subjects who were dosed and had at least one postbaseline assessment for each question. 
• Descriptive summary of subjects who had treatment-emergent suicidal ideation, subjects 
who had new suicidal ideation as well as subjects who had worsening suicidal ideation. 
The denominator is the number of dosed subjects with both baseline and at least one 
postbaseline suicidal ideation assessment. 
• Descriptive summary of subjects who had treatment-emergent suicidal behavior. The 
denominator is the number of subjects who answered “No” to all suicidal behavior 
questions at baseline and had at least one postbaseline suicidal behavior assessment. 
Listing of subjects having treatment-emergent suicidal ideation will be provided. Subjects who 
had new suicidal ideation and subjects who had worsening suicidal ideation will be flagged. The 
listing will display both baseline and postbaseline Suicidal Ideation Scores for each subject. 
Listing of subjects having treatment-emergent suicidal behavior will also be provided. 
 
9.8 Interim Safety Analyses 
Blinded safety data will be reviewed on an ongoing basis by the Sponsor and the Medical 
Monitor, while unblinded safety data are reviewed on a quarterly basis by the IDMC. The IDMC 
has been assembled to perform ongoing review of safety and tolerability data collected on 


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tofersen during this study. Based on its ongoing assessment of the safety and tolerability of 
tofersen, the IDMC will provide recommendations to the Sponsor for modifying or continuing 
the study as planned. 
Details on the safety assessments, frequency of review, meeting schedules and controlled access 
to unblinded data at the interim safety analyses are outlined in the IDMC Charter. 
10. Immunogenicity Data 
The immunogenicity population, described in Section 4.2, will be used for all analyses of 
immunogenicity data. 
• For immunogenicity, the baseline value is defined as the latest immunogenicity data 
collected at any time prior to the first dose. If no immunogenicity data are collected prior 
to the first dose, the baseline value is missing and will be imputed as anti-drug antibody 
negative for immunogenicity analyses. 
• Subjects with at least one confirmed post-treatment positive result will be considered 
treatment-emergent positive for anti-drug antibodies if their baseline result is negative. 
• Subjects where none of the post-treatment samples were positive for anti-drug antibodies 
will be considered negative regardless of their baseline result 
• For subjects that are confirmed positive at baseline and have at least one post-treatment 
sample with a ≥ 2-fold increase in titer will be considered positive for anti-drug 
antibodies. Subjects that are positive at baseline, with subsequent post-treatment samples 
titers that are within 2-fold will be considered negative for anti-drug antibodies. If there 
are any samples which the lab was able to confirm the screen was ADA positive but 
could not determine the magnitude of the positive response in time for database lock 
these will be considered as being ≥ 2-fold for the purpose of this analysis. 
• Numbers and percentage of subjects who develop antibodies will be determined and 
summarized by treatment groups. 
The same summary will be provided for subjects with positive baseline results and for subjects 
with negative or missing baseline results, separately. 
In addition, for subjects that are considered anti-drug antibody positive (using definition above, 
based on whether they have negative or positive baseline) with final immunogenicity data, the 
following may be evaluated: 
o Persistent anti-drug antibody response: 


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• More than one postbaseline positive time point that are ≥112 days apart 
or 
 
• One or more postbaseline positive time point, but < 112 days of evaluable 
data post first positive time point. 
 
o Transient anti-drug antibody response: 
• A single positive postbaseline time point, followed by ≥112 days results 
which are all negative. 
or 
 
• Two or more positive postbaseline data points with <112 days apart, with 
later negative samples that are ≥112 days apart from the first positive 
result. 
 
The categorization of subjects may change when integrated with further data in the integrated 
analyses. 
The incidence of AEs selected by specified SMQ (SMQ for each of hypersensitivity, 
anaphylactic reaction and angioedema) will be presented for subjects with at least 1 positive 
ADA result at post-baseline. Percentages will be calculated out of the immunogenicity 
population. 
The incidence of AEs selected by specified SMQ (SMQ for each of hypersensitivity, 
anaphylactic reaction and angioedema) will also be presented for subjects with negative ADA 
result at post-baseline. Percentages will be calculated out of the immunogenicity population. 
Descriptive statistics for AUC and Cmax calculated for tofersen PK concentrations will be 
presented separately for subjects with at least 1 positive ADA result at post-baseline, and for 
subjects with negative ADA result at post-baseline. 
A summary of missing data will be presented for immunogenicity overall and broken out by 
relationship to COVID-19. 


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11. Changes to Planned Analyses 
The protocol is being amended to reflect the changes in statistical analyses and will be issued as 
Global Protocol Amendment 8.0. 
The protocol specified that the primary efficacy endpoint, change from baseline to Week 28 in 
the ALSFRS-R total score, will be analyzed as follows depending on 2 scenarios: 
i) 
if the number of deaths across both treatment arms is ≥ 3 (i.e., ≥ 5% deaths out of a 
total of 60 patients in the mITT population) the joint rank test (JRT) methodology to 
account for mortality [Berry 2013] will be used for the primary inference. When 
implementing the JRT methodology, multiple imputation (MI) will be used to handle 
withdrawals. The estimates will be obtained from an ANCOVA for change from 
baseline in ALSFRS-R at Week 28 with missing data imputed using multiple 
imputation. The corresponding nominal p-value from the ANCOVA will be 
presented as sensitivity analysis. 
ii) 
If the number of deaths is < 3 (i.e., < 5% deaths out of a total of 60 patients in the 
mITT population), ANCOVA with MI will be used as the primary analysis method 
for both inference and estimates. The p-value from the JRT will be presented for 
sensitivity analysis. 
 
 
This analysis was also proposed for one of the key secondary endpoints, change from baseline in 
percent predicted SVC. 
This has been amended so that JRT+ MI will be used as the primary efficacy analysis for change 
from baseline to Week 28 in ALFSRS-R total score and also as the primary analysis for change 
from baseline to Week 28 in percent predicted SVC. ANCOVA+MI will be performed as a 
sensitivity analysis for both endpoints. There is the potential that in a small primary population 
even a single patient could have undue influence on the analysis; with this uncertainty the JRT 
may be more appropriate to account for mortality. 
The protocol states that for the ANCOVA analysis for percent predicted SVC (i.e. third ranking 
secondary endpoint) the covariates included will be baseline percent predicted SVC, baseline 
disease duration since symptom onset, and use of riluzole or edaravone. As stated earlier in 
Section 6.1, ANCOVA models for percent predicted SVC will also adjust for baseline ALSFRS- 
R total score. Given that there is a restriction on SVC for enrolment into the study the rate of 
progression may not be adequately adjusted for based on disease duration since symptom onset 
and baseline SVC alone; baseline ALSFRS-R score is more likely to reflect stage of disease and 
rate of progression in combination with these other covariates. 


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12. Summary of Changes from the Previous Version of the SAP 
• Specified samples will be unavailable for analysis at time of database lock 
• Included a listing showing transfer of subjects between sites 
• Clarification on cumulative dose calculation 
• Amended primary efficacy analysis and specified details and rationale in changes to 
planned analyses. Similarly amended primary analysis for percent predicted SVC. 
• Included tipping point analysis as a sensitivity analysis to address any assumptions about 
missing at random 
• Included sensitivity analysis excluding subjects who died from the MI model 
• Included sensitivity analysis for ALSFRS-R total score where baseline NfL is included as 
a covariate 
• Included supplementary analysis for ALSFRS-R total score where subjects with a 
heterozygous D91A mutation are excluded 
• Included additional analyses based on feedback from FDA to compare the treatment 
difference in the mITT population with the non mITT population, and to look at the 
treatment difference in a subset of the population who meet a prespecified slope decline 
between Screening and Day 15. 
• Included baseline ALSFRS-R as a covariate for all ANCOVA analyses of percent 
predicted SVC, and specified this under changes to planned analyses 
• Clarified that HHD megascore supplementary analysis is for each of upper and lower 
extremities. 
• Removed joint rank p-value from subgroup analysis of HHD megsacore as it is not 
applicable 
• Clarified MI model where treatment is being included in the model, and the model will be 
run separately for each population 
• Clarified sensitivity analyses of joint rank for ALSFRS-R 
• Clarified for the ALSFRS-R slope of decline analysis that all postbaseline assessments 
will be included 
• 
 
 
• Clarified exploratory analyses for Kings and Mitos disease staging 
• Clarified ventilation diary reconciliation and handling of discrepancies, presentation of 
ventilation profile plots and supplementary analysis for time to death or permanent 
ventilation 


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• Added supplementary analysis for time to death or permanent ventilation using also 
ALSFRS-R as a source where hours of vent use are unknown 
• For subgroup analysis indicated that median values may be used instead of tertile to 
determine subgroup categories for baseline disease duration since symptom onset and 
baseline NfL plasma level. Clarification of inclusion of riluzole/edaravone in the model 
• Removed descriptive statistics from MI imputed datasets for 
pharmacodynamic/biomarker endpoints as this is not appropriate 
• Indicated that CSF plasma may not be available at time of database lock and may be 
analyzed at a later stage 
• Added clarification that subgroup analysis will be performed in key 
pharmacodynamic/biomarker endpoints 
• Changed radiculitis/myelitis in AEs of note to a broader category for serious neurologic 
events. Also amended so that incidence rates are also presented. 
• Included SMQ for anaphylactic reaction and angioedema as part of the hypersensitivity 
SMQ selection when summarizing relationship with immunogenicity 




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Ohashi Y, Tashiro K, Itoyama Y, et al. [Study of functional rating scale for amyotrophic lateral 
sclerosis: revised ALSFRS(ALSFRS-R) Japanese version]. No To Shinkei. 2001;53(4):346-55. 
Permutt T and Li F. Trimmed means for symptom trials with dropouts. 2015 Joint Statistical 
Proceeding Meetings 
Proudfoot M, Jones A, Talbot K, et al. The ALSFRS as an outcome measure in therapeutic trials 
and its relationship to symptom onset. Amyotroph Lateral Scler Frontotemporal Degener. 
2016;17(5-6):414-25. Epub 2016/02/11. 
 
Schafer JL. Analysis of Incomplete Multivariate Data. 1 ed. London: Chapman & Hall/CRC 
Press; 1997. 430 p. 
Schafer JL. Multiple imputation: a primer. Stat Methods Med Res. 1999;8(1):3-15 
ICH E9 (R1) Addendum 2017 


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Appendix A: Derivation of Demographic and Baseline Characteristics 
BMI will be calculated as weight (kg) / height2 (m2). 
Time since ALS symptom onset will be calculated in months as (date of baseline ALSFRS-R 
score – date of ALS symptom onset)/30.4375. Time since ALS diagnosis will be calculated in 
months as (date of baseline ALSFRS-R score – date of ALS diagnosis)/30.4375. For the purpose 
of these calculations partial dates for ALS symptom onset or ALS diagnosis will be imputed as 
follows: missing day will be imputed with 15th and missing month/day will be imputed with 
January 15th. 
The prerandomization ALSFRS-R slope will be calculated using the ALSFRS-R score at 
baseline (Day 1) i.e. Baseline ALSFRS-R score – maximum possible score of 48/duration of 
symptom onset, where duration of symptom onset will be calculated as (date of baseline 
ALSFRS-R score – date of symptom onset)/30.4375. Partial dates for symptom onset will be 
handled as defined above. 


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Appendix B: Derivation and Imputation of Clinical Function Endpoint 
ALSFRS-R 
The ALSFRS-R has been demonstrated to predict survival. The ALSFRS-R measures 4 
functional domains, comprising bulbar function (speech, salivation, swallowing), fine motor 
skills (handwriting, cutting food and handling utensils, dressing and hygiene), gross motor skills 
(turning in bed, walking, climbing stairs), and respiratory function (dyspnea, orthopnea, 
respiratory insufficiency). Each domain consists of 3 items, each scored from 0 to 4 with higher 
scores representing better function. Therefore, the total possible score for ALSFRS-R is 48. 
At each study site, the same qualified and trained study site staff member will consistently 
perform the ALSFRS-R for a subject. A qualified and trained backup ALSFRS-R rater will be 
identified in case the primary rater is unavailable. This study site staff member will remain 
blinded to subjects’ treatment assignments and to the results of other assessments. 
The ALSFRS-R total score will be considered missing if more than 3 individual item scores are 
missing. If no more than 3 (≤ 3) individual item scores are missing and each functional domain 
has at least one individual item score available, the functional domain score with any missing 
item score(s) will be calculated by the following formula: 
ALSFRS-R domain score = [(average of all answered item scores) x 3]. 
The ALSFRS-R total score is the sum of the 4 functional domain scores. If 3 individual item 
scores are missing from the same functional domain, then the ALSFRS-R domain score is 
considered as missing and the total score is calculated by the following formula: 
ALSFRS-R total score = average of all answered item scores from other 3 domains x 12. 
ALS Milano-Torinos Staging (MITOS) 
This staging system captures the observed progressive loss of independence and function in 
ALS. This defines clinical milestones in ALS progression by los of independence in 4 key 
domains on the ALSFRS: swallowing, walking/self-care, communicating and breathing. 
Stages are defined as follows: 
Stage 0: functional involvement but no loss of independence on any domain; 
Stages 1-4: number of domains in which independence was lost; 
Stage 5: death. 
Figure 5 below demonstrates how the ALSFRS-R domains are mapped to the stages [Chio 
2015]: 


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Figure 5: Functional domains and stages 
 
 
 
A score is assigned for each of the 4 functional domains: movement, swallowing, 
communicating, breathing 
For movement domain, 
 
If a patient scores 0 or 1 on Q8 OR if they score 0 or 1 on Q6 they get assigned a functional 
score of 1 for this domain. Any other scores on these 2 questions the patient is assigned 0 
functional score for this domain. 


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For swallowing domain, 
 
If a patient scores 0 or 1 on Q3 they get assigned a functional score of 1 for this domain. Any 
other scores on this question the patient is assigned 0 functional score for this domain. 
For communicating domain, 
 
If a patient scores 0 or 1 on Q1 AND if they score 0 or 1 on Q4 they get assigned a functional 
score of 1 for this domain. Any other combination of scores on these 2 questions the patient is 
assigned 0 functional score for this domain. 
For breathing domain, 
 
If a patient scores 0 or 1 on Q10 OR if they score 0, 1 or 2 on Q12 they get assigned a functional 
score of 1 for this domain. Any other scores on these 2 questions the patient is assigned 0 
functional score for this domain. 
Their overall ALS-MITOS Staging is then assigned by summing the scores across the domains: 
Stage 
Functional domain lost 
0 
None 
1 
1 domain 
2 
2 domain 
3 
3 domains 
4 
4 domains 
5 
death 
 
 
The staging will be applied to each subject using the ALSFRS-R scores at each visit. Observed 
data will be used. 
Kings’ Staging 
King’s staging is based on clinical milestones that consider involvement of 1-3 anatomical 
regions (Stages 1, 2, 3) and the need for gastrostomy (Stage 4a) and non-invasive ventilations 
(Stage 4b). Figure 6 demonstrates how King’s staging is determined based on ALSFRS. 


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Figure 6: Kings’ Staging 
 
 
 
 
 
Stages 1, 2 and 3 are based on the number of regions with loss in function. Stage 1 is loss of 
function in 1 region, stage 2 is loss of function in 2 regions and stage 3 is loss of function in all 3 
regions. The regions are bulbar, lower limb and upper limb, defined as follows: 
If Q1 (speech), Q2 (salivation) or Q3 (swallowing) are scored 0 to 3 (i.e. anything except 
normal) this indicates loss of function in the bulbar region 
If Q4 (handwriting) or Q5a (cutting food and handling utensils (subjects without gastrostomy)) 
are scored 0 to 3 this indicates loss of function in the upper limbs 
If Q8 (walking) is scored 0 to 3 i.e. anything except normal, this indicates loss of function in the 
lower limbs 
Stages 4a and 4b are defined as follows: 




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will be calculated as [observed SVC divided by predicted SVC] x 100%. The predicted SVC is 
adjusted by sex, age, height, which is programmed into and performed by the equipment used. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
HHD 
 
Sixteen muscle groups (left and right shoulder flexion, left and right elbow flexion, left and right 
wrist extension, left and right abduction index finger, left and right abduction thumb, left and 
right abduction 5th digit, left and right knee extension, and left and right ankle dorsiflexion) will 
be examined. These are split into upper extremities (left and right shoulder flexion, left and right 
elbow flexion, left and right wrist extension, left and right abduction index finger, left and right 
abduction thumb, left and right abduction 5th digit) and lower extremities (left and right knee 
extension, and left and right ankle dorsiflexion). At each visit, each muscle will be collected as 
Best Trial 1 and Best Trial 2 and the maximum value of the measures will be used for the 
analysis. In some cases a third trial may be required and will also be collected. 
Any missing muscle strength with a reason of ‘UNABLE TO TEST’ will be imputed as 0 for 
analysis. 
Megascore 
Mean and standard deviation (SD) for each muscle will be established separately for the mITT 
and non mITT populations from the baseline values of subjects in the relevant population in this 
trial. For the purpose of calculating megascore the mean and SD of the baseline value will be 
used across all subjects in the corresponding population regardless of treatment group. The 


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muscle strength values will be normalized to Z scores as (measurement at visit – baseline 
mean)/baseline SD and averaged to provide HHD overall megascore. The overall megascore is 
created by averaging all eight bilateral measurement Z scores, if no more than 10 (≤ 10) 
measures are missing. The overall megascore will be considered missing if more than 10 
measures are missing out of 16 total measures. 
A megascore is also calculated separately for each of upper and lower extremities using the 
relevant muscles only. The upper extremities megascore is created by averaging all six bilateral 
measurement Z scores, if no more than 8 (i.e. ≤ 8) measures are missing. The upper extremities 
megascore will be considered missing if more than 8 measures are missing out of 12 total 
measures. The lower extremities megascore is created by averaging both bilateral measurement 
Z scores, if no more than 2 (i.e. ≤ 2) measures are missing. The lower extremities megascore will 
be considered missing if more than 2 measures are missing out of 4 total measures. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Version No.: Final V2.0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
] X 100 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 






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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 
 


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Protocol 233AS101 
VALOR (Part C) 
Study Number: 233AS101 Valor 
Statistical Analysis Plan 
Version No.: Final V2.0 
 
 
 
 
 
 
 


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Appendix D: Derivation of C-SSRS 
The Columbia Suicide Severity Rating Scale (C-SSRS) is an assessment that evaluates suicidal 
ideation and behavior. C-SSRS measurements are collected with respect to “Lifetime: time 
he/she felt most suicidal” at baseline, and with respect to “Since last visit” at last visit (Day 57 
for Part A and Day 169 for Part B) and ET visit. 
There are 11 common “Yes/No” questions at baseline and postbaseline visits. Five questions on 
suicidal ideation and five questions on suicidal behavior are re-ordered and follow increasing 
severity order respectively as shown in Table D1. In particular, only patients who answered 
“Yes” to question 2 will proceed to question 3, 4 and 5. Thus, for any subjects who answered 
“No” to question 2, an answer “No” will also be assumed to question 3, 4, and 5. An additional 
“Yes/No” question is used to record if subject had committed suicide in postbaseline visits. 
Table D1: C-SSRS re-ordered questions 
 
Suicidal Ideation 
Question 1 
Wish to be dead 
Question 2 
Non-specific active suicidal thoughts 
Question 3 
Active suicidal ideation with any methods (not plan) 
without intent to act 
Question 4 
Active suicidal ideation with some intent to act, without 
specific plan 
Question 5 
Active suicidal ideation with specific plan and intent 
Suicidal Behavior 
Question 6 
Preparatory acts or behavior 
Question 7 
Aborted attempt 
Question 8 
Interrupted attempt 
Question 9 
Actual attempt 


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Question 10 
Suicidal behavior 
Question 11 (postbaseline visit 
only) 
Suicide 
Self-Injurious Behaviour without Suicidal Intent 
Question 12 
Self-injurious behavior without suicidal intent 
 
 
A subject is considered to have suicidal ideation at the period of interest if a “Yes” is answered 
to any of the five suicidal ideation questions (Question 1-5). A subject is considered to have 
suicidal behavior at the period of interest if a “Yes” is answered to any of the five suicidal 
behavior questions (Question 6-10) at baseline or a “Yes” is answered to any of the six suicidal 
behavior questions (Question 6-11) at postbaseline visit. 
A subject’s Suicidal Ideation Score is defined as the maximal suicidal ideation question number 
(maximal of 1-5) with an answer “Yes” per visit. The score is defined as 0 if the subject 
answered “No” to all 5 Suicidal Ideation questions at that visit. A subject is considered to have 
treatment-emergent suicidal ideation if the subject had either new or worsening suicidal ideation. 
A subject is considered to have new suicidal ideation if the subject’s Suicidal Ideation Score 
increased at postbaseline visit compared to a score 0 at baseline. A subject is considered to have 
worsening suicidal ideation if the subject’s Suicidal Ideation Score increased at postbaseline visit 
compared to a positive score at baseline. 
A subject is considered to have treatment-emergent suicidal behavior if the subject answered 
“Yes” to any suicidal behavior questions at any postbaseline visit while answered “No” to all 
suicidal behavior questions at baseline. 






 
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