An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed and Presymptomatic Spinal Muscular Atrophy
Phase: PHASE2
Conditions: Spinal Muscular Atrophy
Sponsor: Biogen

COVER PAGE 
 
Oﬃcial Title: 
 
 
An Open-Label Study to Assess the Eﬃcacy, Safety, Tolerability, and 
Pharmacokinetics of Multiple Doses of ISIS 396443 Delivered 
Intrathecally to Subjects With Genetically Diagnosed and 
Presymptomatic Spinal Muscular Atrophy 
 
NCT Number: NCT02386553 
Document Date: 17 October 2021 
 

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 
 
PROTOCOL NUMBER: 
232SM201 
 
Biogen Idec Research Limited 
Innovation House 
70 Norden Road 
Maidenhead Berkshire 
SL6 4AY 
United Kingdom 
 
PHASE OF DEVELOPMENT: 
2 
 
 
PROTOCOL TITLE: An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and 
Pharmacokinetics of Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With 
Genetically Diagnosed and Presymptomatic Spinal Muscular Atrophy 
 
 
EUDRA CT NO:  
 
2014-002098-12 
 
 
 
DATE: 
17 October 2021 
Version 9 
Final 
 
Supersedes previous Version 8 dated 12 November 2019. 
 
 
 

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SPONSOR SIGNATURE PAGE 
 
Protocol 232SM201 was approved by: 
 
 
______________________________ 
 
 
 
_________________ 
, MD, PhD 
 
 
 
 
 
Date 
  
Biogen  

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TABLE OF CONTENTS 
SIGNATURE OF BIOGEN THERAPEUTIC AREA HEAD ........................................................2 
1. 
SYNOPSIS ...................................................................................................................9 
2. 
LIST OF ABBREVIATIONS.....................................................................................14 
3. 
SPONSOR INFORMATION .....................................................................................16 
4. 
INTRODUCTION ......................................................................................................17 
4.1. 
Overview of Spinal Muscular Atrophy .......................................................................17 
4.2. 
Current Therapies for Spinal Muscular Atrophy ........................................................18 
4.3. 
Nusinersen ..................................................................................................................18 
4.3.1. 
Mechanism of Action .................................................................................................18 
4.3.2. 
Chemistry ....................................................................................................................18 
4.3.3. 
Preclinical Experience ................................................................................................19 
4.3.4. 
Clinical Experience .....................................................................................................19 
4.4. 
Study Rationale ...........................................................................................................20 
4.5. 
Rationale for Dose and Schedule Selection ................................................................22 
5. 
SCHEDULE OF ACTIVITIES FOR STUDY 232SM201 ........................................23 
5.1. 
Schedule of Activities:  Screening Through Day 779 ................................................23 
5.2. 
Schedule of Activities:  Day 897 Through Day 2891 (End of Study) ........................29 
6. 
STUDY OBJECTIVES AND ENDPOINTS ..............................................................35 
6.1. 
Objectives ...................................................................................................................35 
6.1.1. 
Primary Objective .......................................................................................................35 
6.1.2. 
Secondary Objectives .................................................................................................35 
6.2. 
Endpoints ....................................................................................................................35 
6.2.1. 
Primary Endpoint ........................................................................................................35 
6.2.2. 
Secondary Endpoints ..................................................................................................35 
 
36 
7. 
STUDY DESIGN .......................................................................................................38 
7.1. 
Study Overview ..........................................................................................................38 
7.2. 
Overall Study Duration and Follow-Up .....................................................................38 
7.2.1. 
Screening ....................................................................................................................38 
7.2.2. 
Treatment ....................................................................................................................38 
7.2.3. 
Follow-Up ...................................................................................................................39 

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7.3. 
Study Stopping Rules .................................................................................................39 
7.4. 
End of Study ...............................................................................................................39 
8. 
SELECTION OF SUBJECTS ....................................................................................40 
8.1. 
Inclusion Criteria ........................................................................................................40 
8.2. 
Exclusion Criteria .......................................................................................................40 
9. 
ENROLLMENT AND REGISTRATION PROCEDURES ......................................42 
9.1. 
Screening and Enrollment ...........................................................................................42 
9.2. 
Registration of Subjects ..............................................................................................42 
9.3. 
Blinding Procedures ....................................................................................................42 
10. 
DISCONTINUATION OF STUDY TREATMENT AND WITHDRAWAL 
OF SUBJECTS FROM THE STUDY ........................................................................43 
10.1. 
Discontinuation of Study Treatment ...........................................................................43 
10.2. 
Withdrawal of Subjects From Study ...........................................................................43 
11. 
STUDY TREATMENT USE .....................................................................................44 
11.1. 
Regimen ......................................................................................................................44 
11.2. 
Modification of Dose and/or Treatment Schedule ......................................................44 
11.3. 
Precautions ..................................................................................................................44 
11.4. 
Compliance .................................................................................................................45 
11.5. 
Concomitant Therapy and Procedures ........................................................................45 
11.5.1. 
Concomitant Therapy .................................................................................................45 
11.5.1.1. 
Allowed Concomitant Therapy ...................................................................................45 
11.5.1.2. 
Disallowed Concomitant Therapy ..............................................................................45 
11.5.2. 
Concomitant/Ancillary Procedures .............................................................................45 
12. 
STUDY TREATMENT MANAGEMENT ................................................................46 
12.1. 
Nusinersen ..................................................................................................................46 
12.1.1. 
Nusinersen Preparation ...............................................................................................46 
12.1.2. 
Nusinersen Storage .....................................................................................................46 
12.1.3. 
Nusinersen Handling and Disposal .............................................................................47 
12.1.4. 
Nusinersen Accountability ..........................................................................................47 
13. 
EFFICACY, PHARMACOKINETIC, 
 
ASSESSMENTS.........................................................................................................48 
13.1. 
Efficacy Assessments .................................................................................................48 
 
49 

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13.1.2. 
Growth Parameters .....................................................................................................49 
13.1.3. 
Motor Milestones ........................................................................................................50 
13.1.4. 
Motor Function Assessments ......................................................................................52 
13.1.4.1. 
Children’s Hospital of Philadelphia Infant Test for Neuromuscular Disease ............52 
13.1.4.2. 
Hammersmith Functional Motor Scale – Expanded ...................................................52 
 
53 
 
53 
 
53 
 
53 
 
54 
 
54 
 
55 
 
 
55 
 
55 
 
55 
 
56 
 
56 
 
56 
13.2. 
Pharmacokinetic (Nusinersen Concentration) Assessments .......................................57 
 
57 
13.4. 
Immunogenicity Assessments ....................................................................................57 
 
57 
14. 
SAFETY ASSESSMENTS ........................................................................................59 
14.1. 
Clinical Safety Assessments .......................................................................................59 
14.1.1. 
Neurological Examinations ........................................................................................59 
14.1.2. 
Electrocardiograms .....................................................................................................60 
14.1.3. 
Echocardiograms ........................................................................................................60 
14.1.4. 
Physical Examinations ................................................................................................60 
14.1.5. 
Vital Signs ..................................................................................................................60 
14.2. 
Laboratory Safety Assessments ..................................................................................60 
15. 
SAFETY DEFINITIONS, RECORDING, REPORTING, AND 
RESPONSIBILITIES .................................................................................................63 

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15.1. 
Definitions ..................................................................................................................63 
15.1.1. 
Adverse Event .............................................................................................................63 
15.1.2. 
Serious Adverse Event ................................................................................................63 
15.1.3. 
Prescheduled or Elective Procedures or Routinely Scheduled Treatments ................64 
15.2. 
Safety Classifications ..................................................................................................64 
15.2.1. 
Investigator Assessment of Events .............................................................................64 
15.2.2. 
Relationship of Events to Study Treatment or Lumbar Puncture Procedure..............64 
15.2.3. 
Severity of Events .......................................................................................................66 
15.2.4. 
Expectedness of Events ..............................................................................................66 
15.3. 
Monitoring and Recording Events ..............................................................................66 
15.3.1. 
Adverse Events ...........................................................................................................66 
15.3.2. 
Serious Adverse Events ..............................................................................................66 
15.3.3. 
Immediate Reporting of Serious Adverse Events .......................................................67 
15.3.3.1. 
Deaths .........................................................................................................................67 
15.3.4. 
Suspected Unexpected Serious Adverse Reactions ....................................................68 
15.4. 
Procedures for Handling Special Situations ...............................................................68 
15.4.1. 
Overdose .....................................................................................................................68 
15.4.2. 
Medical Emergency ....................................................................................................68 
15.5. 
Safety Responsibilities ................................................................................................69 
15.5.1. 
The Investigator ..........................................................................................................69 
15.5.2. 
The Sponsor ................................................................................................................69 
16. 
STATISTICAL METHODS AND DETERMINATION OF SAMPLE SIZE ...........70 
16.1. 
Efficacy .......................................................................................................................70 
16.1.1. 
Analysis Population ....................................................................................................70 
16.1.2. 
Methods of Analysis ...................................................................................................70 
16.1.2.1. 
Analysis of the Primary Endpoint...............................................................................70 
16.1.2.2. 
Analysis of the Secondary Endpoints .........................................................................71 
 
72 
16.2. 
Pharmacokinetics ........................................................................................................73 
16.2.1. 
Analysis Population ....................................................................................................73 
16.2.2. 
Methods of Analysis ...................................................................................................73 
 
73 

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16.3.1. 
Analysis Population ....................................................................................................73 
 
73 
16.4. 
Immunogenicity ..........................................................................................................74 
16.4.1. 
Analysis Population ....................................................................................................74 
16.4.2. 
Methods of Analysis ...................................................................................................74 
 
74 
 
74 
 
74 
16.6. 
Safety ..........................................................................................................................74 
16.6.1. 
Analysis Population ....................................................................................................74 
16.6.2. 
Methods of Analysis ...................................................................................................74 
16.6.2.1. 
Adverse Events ...........................................................................................................74 
16.6.2.2. 
Clinical Laboratory Results ........................................................................................75 
16.6.2.3. 
Vital Signs ..................................................................................................................75 
16.6.2.4. 
ECGs ...........................................................................................................................75 
16.6.2.5. 
Echocardiograms ........................................................................................................75 
16.7. 
Interim Analyses .........................................................................................................75 
16.8. 
Sample Size Considerations .......................................................................................75 
17. 
ETHICAL REQUIREMENTS ...................................................................................76 
17.1. 
Declaration of Helsinki ...............................................................................................76 
17.2. 
Ethics Committee ........................................................................................................76 
17.3. 
Subject Information and Consent ...............................................................................76 
17.4. 
Subject Data Protection ..............................................................................................77 
17.5. 
Compensation for Injury .............................................................................................78 
17.6. 
Conflict of Interest ......................................................................................................78 
17.7. 
Registration of Study and Disclosure of Study Results ..............................................78 
18. 
ADMINISTRATIVE PROCEDURES .......................................................................79 
18.1. 
Study Site Initiation ....................................................................................................79 
18.2. 
Quality Control and Quality Assurance ......................................................................79 
18.3. 
Monitoring of the Study..............................................................................................79 
18.4. 
Study Funding .............................................................................................................79 
18.5. 
Publications .................................................................................................................80 

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19. 
FURTHER REQUIREMENTS AND GENERAL INFORMATION ........................81 
19.1. 
External Contract Organizations .................................................................................81 
19.1.1. 
Contract Research Organization .................................................................................81 
19.1.2. 
Interactive Response Technology ...............................................................................81 
19.1.3. 
Electronic Data Capture ..............................................................................................81 
19.1.4. 
Central Laboratories for Laboratory Assessments .....................................................81 
19.2. 
Study Committees .......................................................................................................81 
19.3. 
Changes to Final Study Protocol ................................................................................82 
19.4. 
Ethics Committee Notification of Study Completion or Termination ........................82 
19.5. 
Retention of Study Data ..............................................................................................82 
19.6. 
Study Report Signatory...............................................................................................82 
20. 
REFERENCES ...........................................................................................................83 
21. 
APPENDICES ............................................................................................................87 
APPENDIX A. LABORATORY ANALYTES ..........................................................................88 
22. 
SIGNED AGREEMENT OF THE STUDY PROTOCOL .........................................89 
 
LIST OF TABLES 
Table 1: 
Schedule of Activities: Screening Through Day 779 .................................................23 
Table 2: 
Pharmacokinetic Sampling Schedule .........................................................................27 
Table 3: 
Schedule of Activities:  Day 897 Through Day 1730.................................................29 
Table 4: 
Schedule of Activities:  Day 1849 Through Day 2891 (End of Study) ......................32 
Table 5: 
Hammersmith Infant Neurological Examination Section 2 - Motor 
Milestones ...................................................................................................................51 
 
54 
Table 7: 
RNA/DNA Assessment Blood Collection Schedule ..................................................57 
Table 8: 
Laboratory Safety Blood Collection Schedule for Subjects with a Screening 
Weight of ≥3 kg ..........................................................................................................61 
Table 9: 
Laboratory Safety Blood Collection Schedule for Subjects with a Screening 
Weight of <3 kg ..........................................................................................................62 
 
LIST OF FIGURES 
Figure 1: 
CMAP for Patients With Type I SMA .......................................................................21 

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1. 
SYNOPSIS 
This is a brief summary.  For details, refer to the body of the protocol. 
Protocol Title: 
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and 
Pharmacokinetics of Multiple Doses of ISIS 396443 Delivered 
Intrathecally to Subjects With Genetically Diagnosed and 
Presymptomatic Spinal Muscular Atrophy 
Protocol Number: 
232SM201 
Version Number: 
9 
Name of Study 
Treatment: 
Nusinersen (also known as BIIB058, ISIS 396443, and Spinraza™) 
Study Phase: 
2 
Study Indication: 
Spinal muscular atrophy (SMA) 
Study Rationale: 
The rationale for this study is to investigate the feasibility of treating 
newborns with genetically diagnosed SMA prior to the onset of 
symptoms, to explore endpoints that may be appropriate in 
presymptomatic SMA, and to explore the efficacy and safety of 
nusinersen in this patient population.  The study was previously 
extended (per Protocol Version 7 [02 October 2019]) for the collection 
of endpoint data in all subjects through 8 years of age in order to assess 
the long-term safety, efficacy, and tolerability of nusinersen. 
Study Objectives 
and Endpoints: 
The primary objective of the study is to examine the efficacy of 
multiple doses of nusinersen administered intrathecally (IT) in 
preventing or delaying the need for respiratory intervention or death in 
infants with genetically diagnosed and presymptomatic SMA.   
The primary endpoint that relates to this objective is the time to 
death or respiratory intervention (invasive or noninvasive 
ventilation for ≥6 hours/day continuously for 7 or more days OR 
tracheostomy).   
Secondary objective and endpoints are as follows: 
• To examine the effects of nusinersen in infants with 
genetically diagnosed and presymptomatic SMA on the 
development of clinically manifested SMA as determined 
by a composite of clinical features seen in subjects with 

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SMA; growth and function; and safety, tolerability, and 
pharmacokinetics (PK) 
o The secondary efficacy endpoints of this study are as 
follows (all assessed at approximately 13 and 
24 months of age, unless otherwise noted): 
▪ Proportion of subjects developing clinically 
manifested SMA as defined by any of the 
following: 
• Age-adjusted weight <5th percentile 
or decrease of ≥2 major weight 
growth curve percentiles (3rd, 5th, 
10th, 25th, or 50th) or a percutaneous 
gastric tube placement for nutritional 
support 
• Failure to achieve the ability to sit 
without support 
• Failure to achieve standing with 
assistance 
• Failure to achieve hands-and-knees 
crawling 
• Failure to achieve walking with 
assistance by 24 months of age 
• Failure to achieve standing alone by 
24 months of age 
• Failure to achieve walking alone by 
24 months of age 
▪ Proportion of subjects alive 
▪ Attainment of motor milestones assessed as 
part of the Hammersmith Infant Neurological 
Examination (Section 2) 
▪ Attainment of motor milestones as assessed 
by World Health Organization criteria 
▪ Change from Baseline in the Children’s 
Hospital of Philadelphia Infant Test of 

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Neuromuscular Disorders motor function 
scale 
▪ Change from Baseline in Hammersmith 
Functional Motor Scale – Expanded 
▪ Change from Baseline in growth parameters:  
weight for age/length, head circumference, 
chest circumference, head-to-chest 
circumference ratio, and arm circumference 
o The secondary safety endpoints of this study are as 
follows: 
▪ Incidence of adverse events and/or serious 
adverse events 
▪ Change from Baseline in clinical laboratory 
parameters, electrocardiograms, and vital 
signs 
▪ Neurological examinations 
o The secondary PK endpoint of this study is 
cerebrospinal fluid (CSF) and plasma nusinersen 
concentrations. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Study Design: 
This is a Phase 2, open-label, multicenter, multinational, single-arm 
study.  The study will assess the efficacy, safety, tolerability, and PK of 
multiple doses of nusinersen in subjects with genetically diagnosed and 
presymptomatic SMA.  The duration of the study was previously 
extended (per Protocol Version 7 [02 October 2019]) to assess 
long-term safety and tolerability and continue to explore the efficacy of 
IT administered nusinersen in these subjects.  All subjects will receive 
nusinersen at 1 dose level, which will be administered as IT injections 
by lumbar puncture. 

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Study Location: 
Global, multicenter 
Number of Planned 
Subjects: 
Up to 25 subjects will be treated in the study. 
Study Population: 
This study will be conducted in subjects ≤6 weeks of age with genetic 
documentation of 5q SMA homozygous gene deletion or mutation or 
compound heterozygous mutation, genetic documentation of 2 or 
3 copies of the survival motor neuron 2 gene, ulnar CMAP ≥1 mV, and 
the absence of signs or symptoms of SMA. 
Detailed criteria are described in Section 8. 
Treatment Groups: 
One dose level will be evaluated, and all subjects will be dosed with 
12 mg (5 mL) regardless of age.  In previous versions of the protocol 
(Versions 1 through 5), the volume of the injection, and thus the dose, 
was adjusted based on the subject’s age on the day of dosing, such that 
each subject received a 12-mg scaled equivalent dose based on CSF 
volume scaling.  Nusinersen will be administered IT on Days 1, 15, 29, 
64, 183, 302, 421, 540, 659, 778, 897, 1016, 1135, 1254, 1373, 1492, 
1611, 1730, 1849, 1968, 2087, 2206, 2325, 2444, 2563, 2682, and 2801 
(±14 days for all days).  
Duration of 
Treatment and 
Follow-up: 
For subjects who meet the eligibility criteria and remain enrolled in the 
study, total study duration will be approximately 8 years.  The study 
will consist of a Screening Period, Treatment Period, and a 
post-treatment follow-up evaluation.  
Subjects who prematurely withdraw from the study are to complete the 
early termination study procedures and observations at the time of 
withdrawal. 

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2. 
LIST OF ABBREVIATIONS 
2′-MOE 
2′-O-(2-methoxyethyl) 
 
 
 
 
AE 
adverse event 
ASO 
antisense oligonucleotide 
 
 
CHOP INTEND 
Children’s Hospital of Philadelphia Infant Test of Neuromuscular 
Disorders 
CI 
confidence interval 
CMAP 
compound muscle action potential 
CNS 
central nervous system 
CRF 
case report form 
CRO 
contract research organization 
CSF 
cerebrospinal fluid 
 
 
 
 
DHA 
Directions for Handling and Administration 
DNA 
deoxyribonucleic acid 
ECG 
electrocardiogram 
FAS 
Full Analysis Set 
FL 
full-length 
GCP 
Good Clinical Practice 
HFMSE 
Hammersmith Functional Motor Scale – Expanded 
HINE 
Hammersmith Infant Neurological Examination 
hnRNP 
heterogeneous nuclear ribonucleoproteins 
 
 
ICF 
informed consent form 
ICH 
International Council on Harmonisation 
IRT 
interactive response technology 
IT 
Intrathecal(ly) 
LP 
lumbar puncture 
mRNA 
messenger ribonucleic acid 
 
 
 
 
PK 
pharmacokinetic(s) 
 
 
PPS 
Per-Protocol Set 
 
 
 
 
RNA 
ribonucleic acid 
SAE 
serious adverse event 
SMA 
spinal muscular atrophy 

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SMN 
survival motor neuron 
SMN1 
survival motor neuron 1 
SMN2 
survival motor neuron 2 
 
 
snRNA 
small nuclear ribonucleic acid 
SUSAR 
suspected unexpected serious adverse reaction 
US 
United States 
WHO 
World Health Organization 
 

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3. 
SPONSOR INFORMATION 
Biogen MA Inc. is the Sponsor of the study in the United States (US).  Biogen Idec Research 
Limited (Biogen Idec) is the Sponsor of the study globally.  Biogen (or designee) will be 
responsible for managing the study globally. 
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 
Biogen Australia PTY Ltd 
Suite 1, Level 3 
123 Epping Road 
North Ryde, NSW 2113 
Australia  
 
For urgent medical issues in which the study’s Medical Director should be contacted, please 
refer to the Study Reference Guide for complete contact information. 
Biogen may transfer any or all of its study-related responsibilities to a contract research 
organization (CRO) and other third parties; however, Biogen retains overall accountability for 
these activities.

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4. 
INTRODUCTION 
4.1. 
Overview of Spinal Muscular Atrophy 
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized 
by degeneration of the motor neurons in the anterior horn of the spinal cord, resulting in atrophy 
of the voluntary muscles of the limbs and trunk.  Despite being a rare disease, prior to the 
availability of therapeutic options, SMA was one of the most common genetic causes of death in 
infants, with a reported birth prevalence ranging from 8.5 to 10.3 per 100,000 live births 
[Arkblad 2009; Jedrzejowska 2010; Prior 2010; Sugarman 2012; Tassie 2013].  The natural 
history of SMA includes 4 major recognized phenotypes that are dependent on age of onset and 
achieved motor abilities.  The most severe form, Type I SMA (equivalent to infantile-onset 
SMA), has a disease onset within the first few months of life; these children are never able to sit 
or walk and usually die from respiratory failure by 2 years of age.  Patients with Type II SMA 
are able to sit but never walk unaided, with symptoms presenting between 6 and 18 months of 
age.  Patients with Type III SMA are able to sit and walk but may become severely and 
increasingly disabled.  Patients with Type IV or adult-onset SMA have an age of onset over 18 
years and have normal life expectancies. 
In 95% of patients with SMA, a deletion in the survival motor neuron 1 (SMN1) gene on 
chromosome 5q11-q13 is found, with the remaining 5% attributable to small mutations in the 
same gene [Helmken 2003; Lefebvre 1995].  SMN1 lies in the telomeric portion of an inverted 
duplication of a region of chromosome 5.  The centromeric half of the duplication contains a 
homologous gene named survival motor neuron 2 (SMN2) that differs from SMN1 by 5 to 
11 nucleotides [Lorson 1999; Monani 1999].  The open reading frames for both genes encode 
proteins with identical amino acid sequences.  Survival motor neuron (SMN) gene transcripts, 
similar to most mammalian transcripts, undergo alternative splicing in which certain exons are 
either included or excluded from the mature protein coding transcripts [Keren 2010].  In 
particular, exon 7 of the SMN1 gene is alternatively spliced with 90% to 95% of the mature 
messenger ribonucleic acid (mRNA) transcripts derived from the SMN1 gene containing exon 7, 
and 5% to 10% of transcripts missing exon 7.  The transcripts missing exon 7 (often referred to 
as Δ7) produce a truncated protein that is defective and unstable [Cho and Dreyfuss 2010].  One 
of the 5 to 11 nucleotide differences between SMN1 and SMN2 is a C to T substitution, which 
occurs in exon 7 of the SMN2 gene resulting in an alternative splicing pattern that favors 
skipping of exon 7.  The result shows that as much as 90% of the transcripts produced from 
SMN2 are missing exon 7.  The remainder, SMN2 transcripts containing exon 7, produces a 
full-length (FL) protein product identical to the SMN1 protein because the C to T substitution is 
silent.  Humans have a variable copy number of the SMN2 gene (0 to 8 copies) [Wirth 2006].  
The number of SMN2 copies and the resulting amount of FL-SMN protein expressed in patients 
with SMA (10% to 40% of normal SMN protein levels) correlate with SMA disease severity, 
thus, SMN2 is a key modifier of disease phenotype [Coovert 1997; Feldkötter 2002; Lefebvre 
1997; Prior 2004]. 

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4.2. 
Current Therapies for Spinal Muscular Atrophy 
Nusinersen, also referred to as BIIB058, ISIS 396443, or Spinraza™, has been approved in over 
55 countries for the treatment of SMA, including in the US (December 2016), European Union 
(May 2017), and other major markets.  The gene therapy, onasemnogene abeparvovec-xioi 
(Zolgensma®) is an AAV9 vector expressing an SMN1 gene delivered intravenously. Zolgensma 
was approved in the US (May 2019) and Japan (March 2020) for the treatment of SMA Type I in 
patients less than 2 years of age, and in the European Union (May 2020) for the treatment of 
5q SMA, with a dosing guidance by body weight up to 21 kg.  Risdiplam (Evrysdi™), is an oral 
SMN2-directed splicing modifier indicated for the treatment of SMA in patients ≥ 2 months of 
age with a clinical diagnosis of SMA Type 1, 2, or 3, or with 1 to 4 SMN2 copies. It was 
approved in the US (August 2020), European Union (March 2021) and has since received 
approval in at least 5 other markets.  
In countries where nusinersen and/or other therapies are not approved, current medical care is 
limited to supportive care, focused on respiratory support, nutritional support, and management 
of resulting musculotendinous contractures and neuromuscular scoliosis through bracing, 
physical therapy, and surgery, with specific guidelines according to age of SMA onset [Finkel 
2017]; [Mercuri 2018]. 
4.3. 
Nusinersen 
4.3.1. 
Mechanism of Action 
Nusinersen is a fully modified, 2′-O-(2-methoxyethyl) [2′-MOE] chimeric antisense 
oligonucleotide (ASO) drug designed to bind to a specific sequence in the intron downstream of 
exon 7 of the SMN2 gene transcript.  The region of the pre-mRNA targeted by nusinersen is 
normally occupied by heterogeneous nuclear ribonucleoproteins (hnRNP) A1/2 proteins, 
masking the U1 small nuclear ribonucleic acid (snRNA) binding site at the 5′-exon-intron 
junction of exon 7.  U1 snRNA base pairs to the sequences that define the 5′-splice site, which is 
thought to be one of the first steps that initiate splicing of an intron.  Nusinersen displaces the 
hnRNP A1/2 proteins from the pre-mRNA binding site, allowing U1 snRNA to bind to the 
exon-intron junction and promote assembly of the spliceosomal complex, thus promoting 
inclusion of exon 7 into the mRNA, which results in production of FL-SMN protein.  
4.3.2. 
Chemistry 
Chemically, nusinersen is a synthetic oligomer of 18 nucleotides (i.e., an 18-mer) that are 
connected sequentially by phosphorothioate linkages.  Each of the 17 internucleotide linkages is 
a 3′-O to 5′-O phosphorothioate diester.  The 18 sugar residues are uniformly modified with 
2′-MOE.  These MOE-modified nucleotides (1) increased affinity to the target mRNA [McKay 
1999], (2) increased resistance to exonucleases and endonucleases (thereby increasing stability in 
tissue) [Geary 2003], and (3) ameliorated some of the high-dose toxicities associated with ASO 
containing only the phosphorothioate linkages [Henry 2000]. 

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The sequence of nusinersen is written as follows: 
5′-MeUMeCAMeCMeUMeUMeUMeCAMeUAAMeUGMeCMeUGG-3ʹ 
where A and G are 2′-MOE nucleosides, MeC is 5-methyl-2′-MOE cytidine,  
and MeU designates 5-methyl-2′-MOE uridine. 
4.3.3. 
Preclinical Experience 
Nusinersen was identified after an extensive screen of >500 2′-MOE oligonucleotides in reporter 
gene assays, in vitro splicing assays, and SMA patient fibroblasts [Hua 2007; Hua 2008].  Data 
have shown that nusinersen promotes a concentration-dependent increase in FL transcripts 
(including exon 7) in patient fibroblast cells, achieving >90% FL-SMN2 transcripts, and forms 
nuclear structures called gems, known to contain SMN protein.  In a mild mouse model of SMA, 
nusinersen promoted inclusion of exon 7 in the SMN2 transgene in a variety of peripheral tissues 
when dosed systemically [Hua 2008] and in central nervous system (CNS) tissue, including the 
spinal cord, when injected into the lateral ventricle.  Nusinersen produced >90% exon 7 inclusion 
in the transgenic mice and increased SMN protein production in motor neurons, resulting in the 
appearance of gems in motor neurons.  These studies were extended to a more severe mouse 
model of SMA (SMA Δ7) [Le 2005], where the CNS delivery of drug produced a 
dose-dependent effect on SMN2 exon 7 inclusion, SMN protein production, and survival.  These 
mice treated with nusinersen demonstrated improved weight gain; improvements in muscle 
morphology, muscle strength, and motor coordination; and improved morphology of the motor 
neuron junctions [Passini 2011].  Furthermore, nusinersen was shown to distribute widely in the 
CNS after intrathecal (IT) administration in monkeys [Passini 2011]. 
The pharmacokinetics (PK) and toxicity of nusinersen were assessed after a single IT lumbar 
bolus injection (1 to 7 mg) in adult monkeys, after 14 weeks (with a 4-week interim sacrifice) of 
repeated IT lumbar bolus injections (0.3 to 3 mg/week or every other week) in juvenile monkeys, 
and after 53 weeks of repeated IT lumbar bolus injections in juvenile monkeys.  In addition, a 
dedicated PK study in adult monkeys was performed to assess the half-life of nusinersen in 
cerebrospinal fluid (CSF), tissues, and plasma.  
See the Investigator’s Brochure for detailed information on nonclinical studies. 
4.3.4. 
Clinical Experience 
Nusinersen has been evaluated in a completed open-label, single-ascending-dose, Phase 1 study 
designed to assess the safety, tolerability, and PK of nusinersen in subjects with SMA 
(ISIS 396443-CS1).  A single dose of nusinersen was administered by IT injection to subjects 
with SMA 2 to 14 years of age.  Four doses (1, 3, 6, and 9 mg) were evaluated sequentially.  
Each dose was studied in a cohort of 6 or 10 subjects, where all subjects received nusinersen. 
Nusinersen was evaluated in 8 additional completed studies, ISIS 396443-CS1, 
ISIS 396443-CS2, ISIS 396443-CS12, ISIS 396443-CS4, ISIS 396443-CS3A, 
ISIS 396443-CS3B, ISIS 396443-CS10, and 232SM202, and is currently being evaluated in 
4 additional ongoing studies, ISIS 396443-CS11, 232SM404, 232SM203, and 232SM302. 

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The primary support for the safety and efficacy of nusinersen in the treatment of SMA is derived 
from the final analysis of Study ISIS 396443-CS3B, the sham-controlled study in subjects with 
infantile-onset SMA, and the final analysis of Study ISIS 396443-CS4, the sham-controlled 
study in subjects with later-onset SMA.  Subjects receiving nusinersen in these 2 studies 
achieved statistically significant improvements in motor function compared with subjects in the 
control arms. 
Uncontrolled studies involving subjects with infantile-onset SMA (Study ISIS 396443-CS3A) 
and later-onset SMA (longitudinal analyses of Studies ISIS 396443-CS2 and ISIS 396443-CS12) 
are highly supportive of the results of the pivotal efficacy studies (Studies ISIS 396443-CS3B 
and ISIS 396443-CS4) and provide evidence of the long-term benefit of treatment with 
nusinersen. 
See the Investigator’s Brochure for detailed information on clinical studies.   
4.4. 
Study Rationale 
This study is being conducted to investigate whether nusinersen can prevent or profoundly 
attenuate the severity of SMA in patients who are presymptomatic.  Patients with SMA almost 
invariably have a “normal period” immediately after birth.  Their activity, weight, and motor 
activities are normal during that period.  Although existing data on patients with presymptomatic 
SMA are scant, evidence indicates that these patients have normal or near-normal motor neuron 
function in that “honeymoon” period.  In Figure 1, the patients with presymptomatic SMA (open 
diamonds) all have compound muscle action potentials (CMAPs) of >2 mV.  Further, when 
followed into the symptomatic period (closed diamonds), these patients have a profound loss in 
the number and activity of motor neurons.  Therefore, the intent of this study is to investigate 
whether nusinersen can prevent the loss of motor neurons that occurs in the early postnatal 
period of patients with SMN1 homozygous deletion or mutation or compound heterozygous 
mutation. 

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Figure 1: 
CMAP for Patients With Type I SMA 
 
Source:  [Swoboda 2005] 
CMAP = compound muscle action potential; SMA = spinal muscular atrophy. 
The following are several important points that support the rationale for this study:  
• Genetic diagnosis of SMA is straightforward and extremely accurate using blood or 
dried blood spots from a heel stick.  It can be done in 3 to 7 days. 
• The penetrance of SMA given a genetic diagnosis is virtually 100%. 
• There is reasonably high genotype-phenotype correlation such that the SMN2 copy 
number can be used to predict the severity of disease (moderate or severe) with 
approximately 80% to 85% accuracy [Burghes and Beattie 2009; Prior 2010; 
Swoboda 2005]. 
• Experience from another genetic pediatric disease with a profound neuromuscular 
phenotype (Pompe disease) suggests that presymptomatic identification and treatment 
of infants lead to markedly improved clinical outcomes compared to treatment 
offered after symptomatic presentation [Chien 2009]. 
The study was previously extended (per Protocol Version 7 [02 October 2019]) for the collection 
of endpoint data in all subjects through 8 years of age in order to assess the long-term safety, 
efficacy, and tolerability of nusinersen. 

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4.5. 
Rationale for Dose and Schedule Selection 
The nusinersen dose and dose interval for this study were selected based on nonclinical 
toxicology and PK observations from studies in monkeys using single-dose and repeat-dosing IT 
administration, consideration of the target tissue concentration anticipated for drug 
pharmacology, and safety data in the completed and ongoing clinical studies of nusinersen to 
date.  Based on the pharmacology and PK results in SMA transgenic mice, it was estimated that 
a target spinal cord tissue concentration between 2 and 10 μg/g will produce 50% to 90% SMN2 
exon 7 inclusion.  Nonclinical studies in juvenile monkeys receiving IT doses of nusinersen 
showed a resulting gradient of distribution of nusinersen along the spinal cord, with mean lumbar 
spinal cord concentrations ranging from 1.6- to 2.3-fold and 2.0- to 3.5-fold higher than thoracic 
and cervical spinal cord levels, respectively.  The dose selected for this multiple-dose clinical 
study (equivalent to 12 mg of nusinersen) is predicted to achieve levels at the high end of this 
range (approximately 10 μg/g lumbar and 3 μg/g cervical spinal cord tissue concentrations) after 
the first dose.   
The loading dose interval (i.e., doses on Days 1, 15, 29, and 64) was selected as the dose interval 
based on the nonclinical PK and pharmacology data to achieve and maintain nusinersen spinal 
cord tissue levels that are predicted to be within the upper end of the pharmacologically active 
range by Day 64 (predicted to be approximately 30 μg/g lumbar and 10 μg/g cervical tissue 
concentrations), while at the same time considering subject safety and convenience for repeated 
lumbar puncture (LP) IT injections.   
The maintenance dose interval (once every 4 months or 119 days) was selected based on 
nonclinical PK and pharmacology data and clinical PK data from subjects in ongoing and 
completed clinical studies, with the goal of maintaining the spinal cord tissue levels of 
nusinersen at a steady-state level within the estimated pharmacologically active range.  The 
elimination half-life of nusinersen from human CSF is approximately 135 to 177 days and was 
estimated based on a limited number of postdose levels.  Although CNS tissue half-life cannot be 
measured in humans, the median terminal elimination half-life was measured in the CNS tissue 
of adult monkeys and was found to be 116 days (approximately 4 months).  Because the site of 
action of nusinersen is within the CNS tissues, these findings support maintenance doses 
administered every 4 months. 
Nusinersen will be administered as an IT injection.  All subjects will be dosed with 12 mg 
(5 mL) regardless of age.  Because results from PK models showed similar concentrations and 
potential for higher efficacy with higher concentrations, the dosing regimen was adjusted to 
12 mg (5 mL) regardless of age, which in result will lower the risk for dosing errors while still 
maintaining favorable safety margins.  Dosing instructions and details regarding administration 
will be provided in the Directions for Handling and Administration (DHA).  In previous versions 
of the protocol (Versions 1 through 5), the volume of the injection, and thus the dose, was 
adjusted based on the subject’s age on the day of dosing, such that each subject received a 12-mg 
scaled equivalent dose based on CSF volume scaling.  Thus, younger subjects were given a 
lower dose of nusinersen, achieved by injecting a smaller volume that was proportional to the 
estimated CSF volume for age, such that the dose volume was equivalent to 5 mL for a 
2-year-old child to adult. 

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5. 
SCHEDULE OF ACTIVITIES FOR STUDY 232SM201 
5.1. 
Schedule of Activities:  Screening Through Day 779 
Table 1: 
Schedule of Activities: Screening Through Day 779 
Study Period 
Screen 
Treatment/Follow-Up 
Study Day 
D -21 
to 
D -1 
D1 
D2 
D15 (±1D) 
D16 
D29 (±1D) 
D30 
D64, D183, D302, 
D421, D540, D659, 
D778 (±14D) 
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7791 
D365, 
D700 
(±14D) 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Informed Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Inclusion/Exclusion 
Criteria 
X 
X2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Medical History 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sibling SMA Data 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Vital Signs and Pulse 
Oximetry 
X 
X 
 
4X3 
X 
X 
 
4X3 
X 
X 
 
4X3 
X 
X 
 
4X3 
X 
X 
Weight 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
Growth Parameters 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
X 
Physical Examination 
X 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
Ventilator Use 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
Neurological 
Examination 
X 
X 
 
2X6 
X 
X 
 
2X6 
X 
X 
 
2X6 
X 
X 
 
2X6 
X 
X 
ECG 
X 
 
 
 
X 
 
 
 
 
 
 
X 
 
 
 
 
 
X 

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Study Period 
Screen 
Treatment/Follow-Up 
Study Day 
D -21 
to 
D -1 
D1 
D2 
D15 (±1D) 
D16 
D29 (±1D) 
D30 
D64, D183, D302, 
D421, D540, D659, 
D778 (±14D) 
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7791 
D365, 
D700 
(±14D) 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Laboratory Safety 
Tests7 
X 
 
 
 
 
X 
 
 
 
X 
 
 
 
X4 
 
 
 
X 
Coagulation 
Laboratory Tests8 
X 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
Immunogenicity 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
X 
CSF PK 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
 
Plasma PK9 
 
 
 
X 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
Study Treatment 
Injection 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
Inpatient Stay 
(24 hours) 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
CHOP INTEND/ 
HFMSE11 
X12 
 
 
 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
X 
HINE Motor 
Milestones 
X12 
 
 
 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
X 
WHO Motor 
Milestones13 
X12 
 
 
 
 
 
 
 
 
 
 
 
 
X4 
 
 
 
X 

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Study Period 
Screen 
Treatment/Follow-Up 
Study Day 
D -21 
to 
D -1 
D1 
D2 
D15 (±1D) 
D16 
D29 (±1D) 
D30 
D64, D183, D302, 
D421, D540, D659, 
D778 (±14D) 
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7791 
D365, 
D700 
(±14D) 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Pre- 
Dose 
LP 
Post
- 
Dose 
Con Med and 
Ancillary Procedure 
Recording 
X-----------------------------------------------------------------------------------------------------------------------------------------------------------X 
AE Collection 
X----------------------------------------------------------------------------------------------------------------------------------------------------------X 
; AE = adverse event; CHOP INTEND = Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders; 
 
; Con Med = concomitant medication; CSF = cerebrospinal fluid; D = day; DNA = deoxyribonucleic acid; ECG = electrocardiogram; HFMSE = Hammersmith 
Functional Motor Scale – Expanded; HINE = Hammersmith Infant Neurological Exam; LP = lumbar puncture; PK = pharmacokinetic(s); 
 
; RNA = ribonucleic acid; SMA = spinal muscular atrophy; 
; Term = termination; WHO = World Health Organization.  
Note:  Monitoring telephone calls will occur on a monthly (±14 days) basis starting on Day 94 and continuing to Day 897.  At telephone contact, changes in concomitant 
medications and AEs will be recorded, as well as information on the subject’s ventilator use and SMA disease status.  Videotaping of the motor milestone assessments, all motor 
function assessments, and physical examinations will be optional. 
1 These safety monitoring visits will occur on the day after the subject receives an injection of study treatment.  At the time of the implementation of Protocol Version 7, onsite 
safety assessments are no longer required per protocol on the day following injection of study treatment; however, a postdose follow-up email or phone call evaluation will be 
required within 1 to 7 days after the dosing visits on Days 64, 183, 302, 421, 540, 659, and 778. 
2 Investigator to check for signs and symptoms consistent with SMA. 
3 Vital signs will be collected at 4 timepoints postdose:  1, 2, 4, and 6 hours (±15 minutes). 
4 These assessments may be performed up to 7 days prior to dosing, if necessary. 
 
 
 
6 Neurological examinations will be conducted at 2 timepoints:  3 and 6 hours after dosing. 
7 Serum chemistry, hematology, urinalysis, and urine total protein; see Appendix A, Table 8, and Table 9 for a list of analytes and collection timepoints based on the subject’s 
weight at Screening.  For subjects ≥3 kg at Screening, once they reach a weight of 5.4 kg or the Day 183 visit, whichever happens first, blood samples for all analytes should be 
collected according to the above schedule.  The blood sample for Cystatin C analysis will not be collected at any timepoint for subjects with a Screening weight of <3 kg.  
Urinalysis will be conducted according to the above schedule, independent of a subject’s weight. 
8 Coagulation testing will be conducted up to 7 days prior to dosing at the time of the implementation of Protocol Version 7, and results must be reviewed prior to dosing. 
9 See Table 2 for the detailed PK sampling schedule.  
 

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10 A blood sample for RNA and DNA assessments will be drawn on Day 184.  For subjects who have already completed Day 184 at the time of the implementation of Protocol 
Version 4, blood samples should be obtained at the next visit.  At the time of the implementation of Protocol Version 6, a blood sample for RNA and DNA assessments will be 
drawn on the same day as injection of study treatment (Day 183) or at the next visit. 
11 CHOP INTEND will be assessed in subjects until they have a maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be assessed.  All subjects 
≥2 years of age will be evaluated using the HFMSE.  See Section 13.1.4 and Section 13.1.4.2.  
12 The CHOP INTEND, HINE, and WHO motor milestone assessments will be conducted as part of the initial screening assessments.  If they are conducted within 7 days prior to 
dosing, they will only need to be performed once; otherwise, they will need to be repeated within 7 days prior to dosing. 
13 WHO motor milestone assessments will be performed by the Investigator or physical therapist at study visits independently of the assessments made by the subject’s caregiver.   
 
 
 
 
 
 
 
 

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Table 2: 
Pharmacokinetic Sampling Schedule 
Study Day 
Timepoints 
Blood Collection 
(mL) 
CSF Collection 
(mL)1 
D1 
Predose 
NA 
0.5 
4 hr (±1 hr) 
0.5 
NA 
D15 
Predose 
NA 
0.5 
D29 
Predose 
NA 
0.5 
D64 
Predose 
0.5 
0.5 
D183 
Predose 
0.5 
0.5 
D302 
Predose 
0.5 
0.5 
D421 
Predose 
0.5 
0.5 
D540 
Predose 
0.5 
0.5 
D659 
Predose 
0.5 
0.5 
D778 
Predose 
0.5 
0.5 
D897 
Predose 
0.5 
0.5 
D1016 
Predose 
0.5 
0.5 
D1135 
Predose 
0.5 
0.5 
D1254 
Predose 
0.5 
0.5 
D1373 
Predose 
0.5 
0.5 
D1492 
Predose 
0.5 
0.5 
D1611 
Predose 
0.5 
0.5 
D1730 
Predose 
0.5 
0.5 
D1849 
Predose 
0.5 
0.5 
D1968 
Predose 
0.5 
0.5 
D2087 
Predose 
0.5 
0.5 
D2206 
Predose 
0.5 
0.5 
D2325 
Predose 
0.5 
0.5 
D2444 
Predose 
0.5 
0.5 
D2563 
Predose 
0.5 
0.5 
D2682 
Predose 
0.5 
0.5 
D2801 
Predose 
0.5 
0.5 
CSF = cerebrospinal fluid; D = day; hr = hour; mRNA = messenger ribonucleic acid; NA = not applicable (no 
collection scheduled); PK = pharmacokinetic; SMA = spinal muscular atrophy. 
Note:  Details on sampling, preparation, and shipment are included in the Study Laboratory Manual. 

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1 Four to 5 mL of CSF will be collected for analyses and for PK assessments (see Section 11.1), but only 0.5 mL 
will be used for the PK analysis. 

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5.2. 
Schedule of Activities:  Day 897 Through Day 2891 (End of Study) 
Table 3: 
Schedule of Activities:  Day 897 Through Day 1730  
 
Treatment/Follow-Up (Each visit can be ±14 days) 
Study Day 
D897 
D1016 
D1135 
D1254 
D1373 
D1492 
D1611 
D1730 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Sibling SMA 
Data 
X 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
Vital Signs and 
Pulse Oximetry1 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
Weight 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
Growth 
Parameters2 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
Physical 
Examination 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
Ventilator Use 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
Neurological 
Examination4 
X3 
 
X 
X3 
 
X 
X3 
 
X 
X3 
 
X 
X3 
 
X 
X3 
 
X 
X3 
 
X 
X3 
 
X 
ECG 
X3 
 
 
 
 
 
 
 
 
X3 
 
 
 
 
 
 
 
 
X3 
 
 
 
 
 
Laboratory 
Safety Tests5 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
Coagulation 
Laboratory Tests6 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
Immunogenicity 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 
X3 
 
 

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31 
subject’s ventilator use and SMA disease status.  Where possible, all visits from Day 897 through Day 1730 can be concluded in 1 day.  The final visit will occur 90 days after 
the last study treatment injection.  Videotaping of the motor milestone assessments, all motor function assessments, and physical examinations will be optional. 
For growth parameters, 
, ECG, laboratory safety tests, CHOP INTEND/HFMSE, WHO motor milestones, 
 
, if an assessment is not performed at a visit, attempts should be made to perform the assessment at the subsequent dosing 
visit(s) until completed; however, an assessment should not be performed more than once at any visit. 
For study visits with a large number of planned assessments, assessments can be completed over 1 to 2 days and assessments for primary and secondary outcomes (e.g., motor 
milestones/functional assessments) should be prioritized. 
1 Vital signs will be taken predose and approximately 1 hour postdose (±15 minutes) at every onsite visit throughout the study. 
2 Growth parameters of body length and/or height (for all subjects), and head circumference, chest circumference, and arm circumference (for subjects up to 36 months of age) 
will be measured. 
3 These assessments may be performed up to 7 days prior to dosing, if necessary. 
4 Sections 1 and 3 of the HINE will be conducted on all subjects ≤24 months of age.  For all subjects >24 months of age, standard neurological examinations, which include 
assessments of mental status, level of consciousness, sensory function, motor function, cranial nerve function, and reflexes, will be conducted.  Neurological examinations are 
conducted within 7 days of dosing and approximately 1 hour after dosing (or when sedation has worn off if it was used). 
5 Among the laboratory measurements, quantitative urine total protein will be assessed at the local laboratory If urinary protein concentration is >0.2 g/L, repeat testing and further 
evaluation should be considered; quantitative urine total protein should be prioritized if there is not enough urine sample for all tests.  
6 Coagulation testing will continue to be conducted at each visit or up to 7 days prior to dosing and results should be reviewed prior to dosing. In situations where predose 
verification of coagulation laboratory results is not feasible or optimal (e.g., prolonged sedation of the subject would be required to allow adequate time for lab processing), the 
Investigator may exercise discretionary clinical judgment and proceed with the LP procedure, based on the subject’s clinical and coagulation lab history.  
7 See Table 2 for the detailed PK sampling schedule.  
 
8 CHOP INTEND will be assessed in subjects until they have a maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be assessed.  All subjects 
≥2 years of age will be evaluated using the HFMSE.  See Section 13.1.4 and Section 13.1.4.2. 
9 WHO motor milestone assessments will be performed by the Investigator or physical therapist at study visits independently of the assessments made by the subject’s caregiver. 
 

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Table 4: 
Schedule of Activities:  Day 1849 Through Day 2891 (End of Study) 
 
Treatment/Follow-Up (Each visit can be ±14 days) 
PTFU 
Study Day 
D1849 
D1968 
D2087 
D2206 
D2325 
D2444 
D2563 
D2682 
D2801 
D2891 
(EOS)/ 
Early 
Term1 
 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Sibling SMA Data 
 
 
 
X 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
 
 
 
X 
 
 
 
 
 
X 
Vital Signs and 
Pulse Oximetry2 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
 
X 
X 
Weight 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
Growth 
Parameters3 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X 
Physical 
Examination 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
Ventilator Use 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
Neurological 
Examination5 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X4 
 
X 
X 
ECG 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X 
Echocardiogram7 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X 
Laboratory Safety 
Tests8 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X 
Coagulation 
Laboratory Tests9 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
Immunogenicity 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X 
CSF PK 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
 
Plasma PK10 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
X4 
 
 
 

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Treatment/Follow-Up (Each visit can be ±14 days) 
PTFU 
Study Day 
D1849 
D1968 
D2087 
D2206 
D2325 
D2444 
D2563 
D2682 
D2801 
D2891 
(EOS)/ 
Early 
Term1 
 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Pre 
LP 
Post 
Study Treatment 
Injection 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
X 
 
 
CHOP INTEND/ 
HFMSE11 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X 
WHO Motor 
Milestones12 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X4 
 
 
 
 
 
 
 
 
X 
Con Med and 
Ancillary 
Procedure 
Recording 
X---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------X 
AE Collection 
X-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------X 
; AE = adverse event; CHOP INTEND = Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders; 
; Con 
Med = concomitant medication; CSF = cerebrospinal fluid; D = day; 
; DNA = deoxyribonucleic acid; 
ECG = electrocardiogram; EOS = End of Study; HFMSE = Hammersmith Functional Motor Scale – Expanded; HINE = Hammersmith Infant Neurological Exam; LP = lumbar puncture; 
 PK = pharmacokinetic(s); 
; PTFU = Post-Treatment Follow-Up; 
 
; RNA = ribonucleic acid; SMA = spinal muscular atrophy; 
 Term = termination; US = United States; 
WHO = World Health Organization.  

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Notes:  Starting from Day 897, follow-up safety monitoring telephone calls or emails will occur 1 to 14 days postdose and every other month for the duration of the study, except for the months when 
in-clinic visits occur.  At telephone contact or via email, changes in concomitant medications and AEs will be recorded, as well as information on the subject’s ventilator use and SMA disease status.  
Where possible, all visits from Day 1849 through Day 2891 can be concluded in 1 day.  The final visit will occur 90 days after the last study treatment injection.  Videotaping of the motor milestone 
assessments, all motor function assessments, and physical examinations will be optional. 
For growth parameters, 
 ECG, echocardiogram, laboratory safety tests, CHOP INTEND/HFMSE, WHO motor milestones, 
 
, if an assessment is not performed at a visit, attempts should be made to perform the assessment at the 
subsequent dosing visit(s) until completed; however,  an assessment should not be performed more than once at any visit. 
For study visits with a large number of planned assessments, assessments can be completed over 1 to 2 days and assessments for primary and secondary outcomes (e.g., motor milestones/functional 
assessments) should be prioritized. 
1 At the Early Termination Visit, age-appropriate assessments should be performed. 
2 Vital signs will be taken predose and approximately 1 hour postdose (±15 minutes) at every onsite visit throughout the study. 
3 Growth parameters of body length and/or height (for all subjects), and head circumference, chest circumference, and arm circumference (for subjects up to 36 months of age) will be measured. 
4 These assessments may be performed up to 7 days prior to dosing, if necessary.  
5 Sections 1 and 3 of the HINE will be conducted on all subjects ≤24 months of age.  For all subjects >24 months of age, standard neurological examinations, which include assessments of mental 
status, level of consciousness, sensory function, motor function, cranial nerve function, and reflexes, will be conducted.  Neurological examinations are conducted within 7 days of dosing and 
approximately 1 hour after dosing (or when sedation has worn off if it was used). 
 
  
7  Echocardiogram will only be assessed locally at the site as per local practice. 
8 Among the laboratory measurements, quantitative urine total protein will be assessed at the local laboratory.  If urinary protein concentration is >0.2 g/L, repeat testing and further evaluation should be 
considered; quantitative urine total protein should be prioritized if there is not enough urine sample for all tests. 
9 Coagulation testing will continue to be conducted at each visit or up to 7 days prior to dosing and results should be reviewed prior to dosing. In situations where predose verification of coagulation 
laboratory results is not feasible or optimal (e.g., prolonged sedation of the subject would be required to allow adequate time for lab processing), the Investigator may exercise discretionary clinical 
judgment and proceed with the LP procedure, based on the subject’s clinical and coagulation lab history.  
10 See Table 2 for the detailed PK sampling schedule.  
 
11 CHOP INTEND will be assessed in subjects until they have a maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be assessed.  All subjects ≥2 years of age will be 
evaluated using the HFMSE.  See Section 13.1.4 and Section 13.1.4.2. 
12 WHO motor milestone assessments will be performed by the Investigator or physical therapist at study visits independently of the assessments made by the subject’s caregiver. 
 
 
 
 
  
 
 
 
16 These assessments will be for US sites and for subjects 5 years of age and older at US sites who have English (US) as their primary language.  

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6. 
STUDY OBJECTIVES AND ENDPOINTS 
6.1. 
Objectives 
6.1.1. 
Primary Objective 
The primary objective of the study is to examine the efficacy of multiple doses of nusinersen 
administered IT in preventing or delaying the need for respiratory intervention or death in infants 
with genetically diagnosed and presymptomatic SMA. 
6.1.2. 
Secondary Objectives 
Secondary objectives of this study are to examine the effects of nusinersen in infants with 
genetically diagnosed and presymptomatic SMA on the following: 
• Development of clinically manifested SMA as determined by a composite of clinical 
features seen in subjects with SMA 
• Growth and function 
• Safety, tolerability, and PK 
6.2. 
Endpoints 
6.2.1. 
Primary Endpoint 
The primary endpoint of the study is the time to death or respiratory intervention (invasive or 
noninvasive ventilation for ≥6 hours/day continuously for 7 or more days OR tracheostomy). 
6.2.2. 
Secondary Endpoints 
Efficacy 
The secondary efficacy endpoints of this study are as follows (all assessed at approximately 13 
and 24 months of age, unless otherwise noted): 
• Proportion of subjects developing clinically manifested SMA as defined by any of the 
following: 
o Age-adjusted weight <5th percentile or decrease of ≥2 major weight growth 
curve percentiles (3rd, 5th, 10th, 25th, or 50th) or a percutaneous gastric tube 
placement for nutritional support 
o Failure to achieve the ability to sit without support 

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o Failure to achieve standing with assistance 
o Failure to achieve hands-and-knees crawling 
o Failure to achieve walking with assistance by 24 months of age 
o Failure to achieve standing alone by 24 months of age 
o Failure to achieve walking alone by 24 months of age 
• Proportion of subjects alive 
• Attainment of motor milestones assessed as part of the HINE (Section 2) 
• Attainment of motor milestones as assessed by World Health Organization (WHO) 
criteria 
• Change from Baseline in the Children’s Hospital of Philadelphia Infant Test of 
Neuromuscular Disorders (CHOP INTEND) motor function scale 
• Change from Baseline in HFMSE 
• Change from Baseline in growth parameters:  weight for age/length, head 
circumference, chest circumference, head-to-chest circumference ratio, and arm 
circumference 
Safety 
The secondary safety endpoints of this study are as follows: 
• Incidence of adverse events (AEs) and/or serious adverse events (SAEs) 
• Change from Baseline in clinical laboratory parameters, electrocardiograms (ECGs), 
and vital signs 
• Neurological examinations 
Pharmacokinetics 
The secondary PK endpoint of this study is CSF and plasma nusinersen concentrations. 
 
 
 
 
 
 
 

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7. 
STUDY DESIGN 
7.1. 
Study Overview 
This is a Phase 2, open-label, multicenter, multinational, single-arm study.  The study will assess 
the efficacy, safety, tolerability, and PK of multiple doses of nusinersen in subjects with 
genetically diagnosed and presymptomatic SMA.  The duration of the study was previously 
extended (per Protocol Version 7 [02 October 2019]) to assess long-term safety and tolerability 
and continue to explore the efficacy of IT administered nusinersen in patients with genetically 
confirmed SMA.  Up to 25 subjects are planned to be treated in the study.  All subjects will 
receive nusinersen.  One dose level will be evaluated, and all subjects will be dosed with 12 mg 
(5 mL) regardless of age.  In previous versions of the protocol (Versions 1 through 5), the 
volume of the injection, and thus the dose, was adjusted based on the subject’s age on the day of 
dosing, such that each subject received a 12-mg scaled equivalent dose based on CSF volume 
scaling.  All subjects will have the opportunity to participate in this study for up to 
approximately 8 years. 
7.2. 
Overall Study Duration and Follow-Up 
The study will consist of a Screening Period, Treatment Period, and a post-treatment follow-up 
evaluation. 
Total study duration for subjects who participate in the study will be approximately 8 years. 
7.2.1. 
Screening 
Subject eligibility for the study will be determined within 3 weeks prior to study entry (Day -21 
to Day -1) and confirmed prior to dosing.  If a subject initially fails any of the screening criteria, 
they will be allowed to be rescreened 1 time during the Screening Period at the discretion of the 
Investigator. 
7.2.2. 
Treatment 
Eligible subjects will be admitted to the study center on Study Day 1, undergo predose 
evaluations, and then receive an LP injection of study treatment.  After the injection on Day 1, 
subjects will remain at the study center for at least 24 hours post-procedure for safety 
monitoring. 
Subjects will return to the study center on Days 15, 29, 64, 183, 302, 421, 540, 659, and 778 for 
follow-up evaluations and subsequent injections, for a total of 10 injections over the study 
period.  For injections received on Day 15 and following visits, subjects will remain at the study 
center for at least 6 hours post-procedure for safety monitoring.  An overnight stay is required for 
the first injection, but is otherwise optional at the discretion of the Investigator.  Safety 
monitoring visits will occur on the day after injections.  At the time of the implementation of 
Protocol Version 7, onsite safety assessments are no longer required per protocol on the day 
following injection of study treatment; however, a postdose follow-up email or phone call 

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evaluation will be required within 1 to 7 days after the dosing visits on Days 64, 183, 302, 421, 
540, 659, and 778.  In addition, the study center will monitor the subject’s condition through 
telephone contact on a monthly basis starting on Day 94 and continuing to Day 897.  Two 
additional study visits will be required on Days 365 and 700 in order to collect information for 
the 13- and 24-month of age assessments; a study treatment injection will not occur at these 
visits.  
A CSF sample will be taken predose on each injection day. 
Subjects will return to the study site on Days 897, 1016, 1135, 1254, 1373, 1492, 1611, 1730, 
1849, 1968, 2087, 2206, 2325, 2444, 2563, 2682, and 2801 (±14 days for all days) for 
subsequent injections of nusinersen and follow-up evaluations (±14 days) over a dosing period of 
approximately 5.5 years.  Subjects will remain at the study site for at least 1 hour postdose for 
safety monitoring and can be discharged at the discretion of the Site Investigator and in 
compliance with the institutional requirements once the subjects have adequately recovered from 
the dosing procedure.  From Day 897 through Day 2801, overnight stays are optional for all 
injections at the discretion of the Investigator.  Study assessments can be performed over 
multiple days if needed.  Follow-up safety monitoring telephone calls will occur 1 to 14 days 
postdose and every other month for the duration of the study, except for the months when 
in-clinic visits occur.  During these calls, changes in concomitant medications, AEs, and 
ventilator use/SMA disease status that have occurred since the last phone call or study visit will 
be recorded. 
7.2.3. 
Follow-Up 
Subjects are to return to the study site for a follow-up evaluation (Final Study Visit on Day 2891) 
approximately 3 months after the last dose of study treatment.  
Subjects who prematurely withdraw from the study are to complete the early termination study 
procedures and observations at the time of withdrawal. 
7.3. 
Study Stopping Rules 
There are no specific stopping rules for this study, but the Investigator should discuss concerns 
relating to individual subjects with the Medical Monitor and the Sponsor to ensure that it is 
appropriate for the subject to continue study treatment. 
The Sponsor may terminate this study at any time, after informing Investigators.  The Sponsor 
(or designee) will notify Investigators if the study is to be placed on hold or terminated or when 
completed. 
7.4. 
End of Study 
The end of study is last subject, last visit (either in-person visit or telephone contact). 

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8. 
SELECTION OF SUBJECTS 
8.1. 
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 of parent(s) or guardian(s) to understand the purpose and risks of the study and 
provide signed and dated informed consent and authorization to use confidential health 
information in accordance with national and local subject privacy regulations. 
2. Age ≤6 weeks at first dose. 
3. Genetic documentation of 5q SMA homozygous gene deletion or mutation or compound 
heterozygous mutation. 
4. Genetic documentation of 2 or 3 copies of SMN2. 
5. Ulnar CMAP ≥1 mV at Baseline. 
6. Receiving adequate nutrition and hydration (without gastrostomy) in the opinion of the 
Investigator. 
7. Body weight ≥3rd percentile for age using appropriate country-specific guidelines. 
8. Gestational age of 37 to 42 weeks for singleton births; gestational age of 34 to 42 weeks 
for twins. 
9. Able to complete all study procedures, measurements, and visits and parent(s) or 
guardian(s)/subject has adequately supportive psychosocial circumstances in the opinion 
of the Investigator. 
8.2. 
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. Hypoxemia (oxygen saturation <96% awake or asleep without any supplemental oxygen 
or respiratory support, or for altitudes >1000 m, oxygen saturation of <92% awake or 
asleep without any supplemental oxygen or respiratory support). 
2. Any clinical signs or symptoms at Screening or immediately prior to the first dosing 
(Day 1) that are, in the opinion of the Investigator, strongly suggestive of SMA. 
3. Presence of an untreated or inadequately treated active infection requiring systemic 
antiviral or antimicrobial therapy at any time during the Screening Period. 

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4. History of brain or spinal cord disease that would interfere with the LP procedures, CSF 
circulation, or safety assessments. 
5. Presence of an implanted shunt for the drainage of CSF or an implanted CNS catheter. 
6. History of bacterial meningitis or viral encephalitis. 
7. Clinically significant abnormalities in hematology or clinical chemistry parameters, as 
assessed by the Investigator, at Screening that would render the subject unsuitable for 
inclusion. 
8. Treatment with an investigational drug given for the treatment of SMA (e.g., albuterol/ 
salbutamol, riluzole, carnitine, sodium phenylbutyrate, valproate, hydroxyurea, etc.), 
biological agent, or device.  Any history of gene therapy, prior ASO treatment, or cell 
transplantation. 
9. Diagnosis of neonatal Respiratory Distress Syndrome requiring surfactant replacement 
therapy or invasive ventilatory support. 
10. The subject’s parent(s) or legal guardian(s) is unable to understand the nature, scope, and 
possible consequences of the study or is unable to or does not agree to comply with study 
requirements. 
11. Ongoing medical condition that, according to the Investigator, would interfere with the 
conduct and assessments of the study.  Examples are medical disability that would 
interfere with the assessment of safety or would compromise the ability of the subject to 
undergo study procedures. 
12. Other unspecified reasons that, in the opinion of the Investigator or Sponsor, make the 
subject unsuitable for enrollment. 

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9. 
ENROLLMENT AND REGISTRATION PROCEDURES 
9.1. 
Screening and Enrollment 
The subject’s legally authorized representative(s) (e.g., parent[s] or legal guardian[s]) must 
provide informed consent before any study-specific screening tests are performed (see 
Section 17.3).  The reason for which a subject was chosen for screening in this study will be 
captured.  When a subject’s parent(s)/guardian(s) signs the informed consent form (ICF), that 
subject is assigned a unique subject identification number through the interactive response 
technology (IRT) system and 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, within the IRT system, and on the screening log. 
9.2. 
Registration of Subjects 
Subjects will be registered after all screening assessments have been completed and after the 
Investigator has verified that the subjects are eligible per criteria in Sections 8.1 and 8.2.  No 
subject may begin treatment until the subject is documented as registered for the study in the IRT 
system.  Any subject identification numbers that are assigned will not be reused even if the 
subject does not receive treatment. 
All subjects will receive nusinersen. 
Refer to the Study Reference Guide for details on registration through the IRT system. 
9.3. 
Blinding Procedures 
Not applicable. 

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10. 
DISCONTINUATION OF STUDY TREATMENT AND 
WITHDRAWAL OF SUBJECTS FROM THE STUDY 
10.1. 
Discontinuation of Study Treatment 
A subject must permanently discontinue study treatment for any of the following reasons: 
• The subject’s parent(s)/legal guardian(s) withdraws consent.   
• The subject experiences a medical emergency that necessitates permanent 
discontinuation of study treatment. 
• At the discretion of the Investigator for medical reasons. 
• At the discretion of the Investigator or Sponsor for noncompliance. 
The primary reason for discontinuation of study treatment must be recorded in the subject’s case 
report form (CRF). 
Subjects who discontinue treatment will complete an early termination visit 4 months (+14 days) 
after administration of the last dose of nusinersen, unless consent is withdrawn (see 
Section 10.2).   
10.2. 
Withdrawal of Subjects From Study 
Subjects must be withdrawn from the study for any one of the following reasons: 
• The subject’s parent(s)/legal guardian(s) withdraws consent.   
• The subject’s parent(s)/legal guardian(s) are unwilling or unable to comply with the 
protocol. 
The primary reason for the subject’s withdrawal from the study must be recorded in the subject’s 
CRF.  
Subjects who prematurely withdraw will be encouraged to complete the early termination 
evaluation assessments at the time of withdrawal (see Table 3). 
Subjects who withdraw from the study will not be replaced. 

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11. 
STUDY TREATMENT USE 
11.1. 
Regimen 
Refer to and follow the DHA. 
Each subject will receive a single IT bolus (1 to 3 minutes) LP injection of nusinersen by 
dedicated study personnel on Days 1, 15, 29, 64, 183, 302, 421, 540, 659, 778, 897, 1016, 1135, 
1254, 1373, 1492, 1611, 1730, 1849, 1968, 2087, 2206, 2325, 2444, 2563, 2682, and 2801 of the 
study using a “spinal anesthesia” needle and a 5-mL syringe.  A 22-gauge spinal anesthesia 
needle is recommended.  The target site for needle insertion is the L3/L4 space, but may be 1 
segment above or 1 to 2 segments below this level, if needed.  Spinal ultrasound or fluoroscopy 
may be used for the LP procedure, if deemed necessary, but is not required.  Local anesthesia 
may be used for the procedure, at the discretion of the study center. 
Prior to each injection, 4 to 5 mL of CSF fluid will be collected for analyses.  CSF will be used 
for measurement of nusinersen PK analyses.  
 
 
 
 
 
 
All subjects will be dosed with 12 mg (5 mL) regardless of age. 
Note that injections should not occur within 72 hours after an immunization. 
If a loading dose is delayed or missed, nusinersen should be administered as soon as possible, 
with at least 14 days between doses, and dosing continued at the prescribed dosing frequency.  In 
the maintenance phase, if a planned dose is delayed or missed, nusinersen should be 
administered as soon as possible and dosing continued at the prescribed dosing frequency. 
11.2. 
Modification of Dose and/or Treatment Schedule 
No adjustment of dose is permitted.  If dosing does not occur as per the schedule of activities, a 
protocol deviation should be logged.  In the event of delayed or missed doses due to, for 
example, a concurrent illness or other circumstances (e.g., COVID-19 pandemic), the 
Investigator should refer to the DHA which includes recommended dosing administration in the 
event of delayed or missed doses. 
11.3. 
Precautions 
There are no protocol-required treatment precautions. 

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11.4. 
Compliance 
Compliance with treatment dosing is to be monitored and recorded by site staff. 
11.5. 
Concomitant Therapy and Procedures 
11.5.1. 
Concomitant Therapy 
A concomitant therapy is any drug or substance administered between Screening and the Final 
Study Visit/Telephone Call. 
11.5.1.1. Allowed Concomitant Therapy 
Any concomitant medications including SMA therapies will be captured in the CRF. 
Approved concomitant therapies may be used at the discretion of the Investigator. 
With implementation of Protocol Version 9, Investigators with participants newly seeking 
combination therapy with other SMA therapies should consult and obtain approval from the 
Medical Monitor. This will be permitted for country-approved SMA therapies if the total number 
of study participants concurrently receiving nusinersen and other SMA therapies has not yet 
reached 20% of all enrolled participants.  This is consistent with primary and secondary 
objectives of this study.  Any participants already receiving combination therapy with other 
SMA therapies at the time of Protocol Version 9 implementation may continue this combination 
therapy regardless of the 20% limit.  
11.5.1.2. Disallowed Concomitant Therapy 
As noted above in Section 11.5.1.1, with implementation of Protocol Version 9, Investigators 
with participants newly seeking combination therapy of nusinersen with other SMA therapies 
should consult the Medical Monitor. Any participants already receiving investigational drug for 
any other condition should discuss with the Medical Monitor.      
11.5.2. 
Concomitant/Ancillary Procedures 
A concomitant/ancillary 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 subject is enrolled in the study and the Final Study Visit/Telephone Call. 

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12. 
STUDY TREATMENT MANAGEMENT 
Study treatment will be manufactured, handled, and stored in accordance with applicable Good 
Manufacturing Practice. 
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 for subjects enrolled in this study.  Once study treatment is 
prepared for a subject, it can only be administered to that subject.  Study treatment vials are for 
one-time use only; any study treatment remaining in the vial should not be used for another 
subject. 
12.1. 
Nusinersen 
Nusinersen is formulated as an isotonic solution at 2.4 mg/mL and is provided as a 5.0-mL fill 
volume in a 6-mL clear glass vial.  Nusinersen drug product contains the heptadecasodium salt of 
an 18-base residue phosphorothioate oligonucleotide. 
The contents of the study treatment label will be in accordance with all applicable regulatory 
requirements.  At a minimum, the label will include a study reference code, drug identifier, 
quantity of dosage units, lot number, and other pertinent information in accordance with local 
laws.  The expiry or use-by date is stored in the IRT system, and printable assignment reports are 
available to site personnel.  Study treatment should not be used after the expiration date. 
12.1.1. 
Nusinersen Preparation 
The individual preparing nusinersen 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 vial(s) or drug, do not use the drug.  The vial(s) in question should be saved at the study site 
and the problem immediately reported to the Sponsor (or designee). 
12.1.2. 
Nusinersen Storage 
Study treatment must be stored in a secure location. 
Nusinersen is to be protected from light and stored long term at 2°C to 8°C in a locked 
refrigerator with limited access.  For the most up-to-date storage requirements, follow the 
instructions provided in the DHA. 

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12.1.3. 
Nusinersen Handling and Disposal 
The Investigator must return all used and unused vials of nusinersen as instructed by the Sponsor 
(or designee), unless approved for onsite destruction. 
If any used nusinersen supplies are to be destroyed at the study site, the institution or appropriate 
site personnel must obtain prior approval from the Sponsor (or designee), by providing, in 
writing, the destruction policy or details of the method of destruction.  After such destruction, the 
Sponsor (or designee) 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. 
Nusinersen 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 (subject-by-subject 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.  By the end of the study, reconciliation must be made between the amount of 
nusinersen supplied, dispensed, and subsequently destroyed or returned to the Sponsor (or 
designee).  A written explanation must be provided for any discrepancies. 

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Videotaping of all motor milestone and motor function assessments will be optional. 
If a subject has or had a sibling with SMA and if consent is given, data for the sibling will be 
collected at 8 timepoints during the course of the study:  at Screening (or the first visit after the 
implementation of Protocol Version 4), Day 897, Day 1254, Day 1611, Day 1968, Day 2325, 
Day 2682, and at the end of the study (or Early Termination Visit).  Data to be collected from 
siblings with SMA will be nonbiologic and noninvasive and will include historical data for 
SMN2 gene copy number, sibling treatment history, etc. (see Table 1 and Table 3 for timing of 
sibling data collection). 
SMA is caused by loss of SMN protein due to a homozygous deletion or mutation or compound 
heterozygous mutation in the SMN1 gene on chromosome 5q11-q13.  Thus, patients with SMA 
are completely dependent on the amount of SMN protein produced by the SMN2 gene.  Genetic 
modifiers, such as the number of copies of the SMN2 gene, are known to impact the eventual 
phenotype of SMA.  The incidence and prevalence of SMA and its subtypes have been reported 
to vary based on country.  One hypothesis for these variances is a difference in the frequency of 
certain genetic mutations that may be associated with different racial and ethnic groups within 
each country.  Therefore, the race/ethnicity of subjects is collected as part of the medical history, 
where local regulations allow. 
 
 
 
 
 
 
 
 
  
 
 
 
13.1.2. 
Growth Parameters 
Growth parameters of body length and/or height (for all subjects), head circumference (for 
subjects up to 36 months of age), chest circumference (for subjects up to 36 months of age), and 
arm circumference (for subjects up to 36 months of age) will be measured.  
Additional parameters of weight-for-age, weight-for-length, and head-to-chest circumference 
ratio will be calculated.  If an assessment is not performed at a visit, attempts should be made to 

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perform the assessment at the subsequent dosing visit(s) until completed; however, an 
assessment should not be performed more than once at any visit. 
13.1.3. 
Motor Milestones 
For the purposes of this protocol, ambulatory will be defined as any subject who has achieved 
independent walking as defined by the WHO Motor Milestones criteria (Test Item #6 – Walking 
Alone).  Videotaping of the WHO and/or HINE motor milestone assessments will be optional.  If 
an assessment is not performed at a visit, attempts should be made to perform the assessment at 
the subsequent dosing visit(s) until completed; however, an assessment should not be performed 
more than once at any visit. 
For all subjects, motor milestones will be assessed using the WHO Motor Milestones criteria 
[WHO Multicentre Growth Reference Study Group 2006; Wijnhoven 2004]. 
For subjects <2 years of age who have achieved or have not yet achieved independent walking, 
motor milestones will be assessed using Section 2 of the HINE, which is composed of 8 motor 
milestone categories as follows:  voluntary grasp, ability to kick in supine position, head control, 
rolling, sitting, crawling, standing, and walking.  Within each motor milestone category, there 
are 3 to 5 levels that can be achieved.  All 8 motor milestones will be tested during each 
assessment.  A subject whose results after testing all appear in the first column (no grasp, no 
kicking, unable to maintain head upright, and so on) has not achieved any motor milestone.  
Motor milestone achievement is depicted by movement from the left side of Table 5 to the right 
side of the table, as denoted by the Milestone Level Progression arrow in the table [Haataja 
1999].  

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Table 5: 
Hammersmith Infant Neurological Examination Section 2 - Motor 
Milestones 
Motor 
Milestone 
Category 
Milestone Level Progression 
(Age Expected in Heathy Infants1) 
 
Voluntary 
grasp 
No grasp 
Uses whole 
hand 
Finger and 
thumb; immature 
grasp 
Pincer grasp 
 
Ability to 
kick (in 
supine) 
No kicking 
Kicks 
horizontal; legs 
do not lift 
Upward 
(vertically) 
[3 months] 
Touches leg 
(4 to 
5 months) 
Touches toes 
(5 to 
6 months) 
Head control 
Unable to 
maintain 
upright 
(<3 months) 
Wobbles 
(4 months) 
All the time 
upright 
(5 months) 
 
 
Rolling 
No rolling 
Rolling to side 
(4 months) 
Prone to supine 
(6 months) 
Supine to 
prone 
(7 months) 
 
Sitting 
Cannot sit 
Sit with 
support at hips 
(4 months) 
Props 
(6 months) 
Stable sit 
(7 months) 
Pivots 
(rotates) 
[10 months] 
Crawling 
Does not lift 
head 
On elbow 
(3 months) 
On outstretched 
hand (4 to 
5 months) 
Crawling flat 
on abdomen 
(8 months) 
On hands 
and knees 
(10 months) 
Standing 
Does not 
support weight 
Supports 
weight (4 to 
5 months) 
Stands with 
support 
(8 months) 
Stands 
unaided 
(12 months) 
 
Walking 
No walking 
Bouncing 
(6 months) 
Cruising 
(holding on) 
[11 months] 
Walking 
independently 
(15 months) 
 
1 Values for healthy infants in [Haataja 1999]. 
The proportion of motor milestone responders is defined based on the 8 motor milestones 
categories, with the exclusion of voluntary grasp using the assessment at the later study visits, as 
follows:  
i. 
Subject demonstrates at least a 2-point increase in the motor milestone category of 
ability to kick or achievement of the maximal score on that category (touching toes) 
or a 1-point increase in the motor milestones of head control, rolling, sitting, 
crawling, standing, or walking; AND  
ii. 
Among the 8 motor milestone categories with the exclusion of voluntary grasp, 
subject demonstrates improvement (defined in [i]) in more categories than worsening.  

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Note:  For the category of ability to kick, similar to the definition of improvement in 
(i) mentioned previously, worsening is defined as at least a 2-point decrease or 
decrease to the lowest possible score of no kicking.  For the other 6 categories, 
worsening is defined as at least a 1-point decrease.  
13.1.4. 
Motor Function Assessments 
Motor function assessments include all assessments listed in Section 13.1.4.1, Section 13.1.4.2, 
and Section 13.1.4.3.  The assessments that are performed at a given visit will depend on the 
subject’s age at that visit and current motor abilities. 
Videotaping of all motor function assessments will be optional. 
13.1.4.1. Children’s Hospital of Philadelphia Infant Test for Neuromuscular Disease 
CHOP INTEND will be assessed in subjects with infantile-onset SMA until they have a 
maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be 
assessed. 
The CHOP INTEND test was specifically designed to evaluate the motor skills of infants with 
significant motor weakness, including infants with SMA [Glanzman 2010].  The 
CHOP INTEND test captures neck, trunk, and proximal and distal limb strength in 14 elicited 
and 2 observational items.  The CHOP INTEND has been established as a safe and reliable 
infant motor measure in infantile-onset SMA and has been validated [Glanzman 2011].  If an 
assessment is not performed at a visit, attempts should be made to perform the assessment at the 
subsequent dosing visit(s) until completed; however, an assessment should not be performed 
more than once at any visit. 
13.1.4.2. Hammersmith Functional Motor Scale – Expanded 
All subjects ≥2 years of age will be evaluated using the HFMSE for the duration of the study.  
Subjects who are ≥2 years of age but have not yet achieved the maximum score of 64 with 
CHOP INTEND will be assessed with both until a CHOP INTEND maximum score of 64 is 
achieved.  The HFMSE should be performed after the CHOP INTEND with an approximately 
15-minute rest period in between to allow the subject to be fully engaged with both assessments. 
The HFMSE is a reliable and validated tool used to assess motor function in children with SMA.  
The scale was originally developed with 20 scored activities and was devised for use in children 
with Type II and Type III SMA with limited ambulation to give objective information on motor 
ability and clinical progression [Main 2003].  The expanded scale includes an additional module 
of 13 items developed to allow for evaluation of ambulatory patients with SMA [O'Hagen 2007].  
The HFMSE has been shown to be highly correlated with other clinical assessments and has 
shown good test-retest reliability.  If an assessment is not performed at a visit, attempts should be 
made to perform the assessment at the subsequent dosing visit(s) until completed; however, an 
assessment should not be performed more than once at any visit. 

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. 
 
 
 
 
  
 
 
 
 
 
 
  

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13.2. 
Pharmacokinetic (Nusinersen Concentration) Assessments 
The following parameters will be calculated to assess the PK of nusinersen: 
• Plasma nusinersen concentrations 
• CSF nusinersen concentrations 
 
 
 
 
 
 
 
13.4. 
Immunogenicity Assessments 
The samples for the anti-nusinersen plasma antibody will be collected in accordance to the 
schedule provided in Table 1, Table 3 , and Table 4 and banked. Samples may be analyzed at the 
Sponsor’s discretion.  
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 

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14. 
SAFETY ASSESSMENTS 
See Section 5 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 nusinersen: 
• Neurological examinations:  Sections 1 and 3 of the HINE will be conducted on all 
subjects ≤24 months of age and will be collected predose, 3 and 6 hours after dosing 
from Screening through Day 779. For all subjects >24 months of age, standard 
neurological examinations will be conducted within 7 days of dosing and 
approximately 1 hour after dosing (or when sedation has worn off if it was used) from 
Day 897 through Day 2891  
• Physical examinations and weight 
• Vital sign measurements:  temperature, pulse rate, resting systolic and diastolic blood 
pressure, and respiratory rate 
• Pulse oximetry 
• 12-Lead ECGs 
• Echocardiograms 
• Concomitant therapy recording 
• AE recording 
14.1.1. 
Neurological Examinations 
Neurological examinations will be performed predose and approximately 3 and 6 hours after 
dosing from Day 1 through Day 779 and within 7 days of dosing and approximately 1 hour after 
dosing from Day 897 through Day 2891.  Please note:  If sedation was used, please allow 
sufficient recovery time for the subject to be fully engaged in the examination.  It is important 
that the data collected truly reflect the subject’s neurological performance. 
The HINE (Sections 1 and 3) will be conducted in all subjects ≤24 months of age.  This standard 
examination (developed by [Dubowitz and Dubowitz 1981]) is a quantitative scorable method 
for assessing the neurological development of infants between 2 and 24 months of age.  The 
examination includes assessment of cranial nerve functions, posture, movements, tone, and 
reflexes. 
For all subjects >24 months of age, standard neurological examinations, which include 
assessments of mental status, level of consciousness, sensory function, motor function, cranial 
nerve function, and reflexes, will be conducted. 

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14.1.2. 
Electrocardiograms 
ECGs will be performed for all subjects at Screening, Day 2, Day 29 postdose, Day 365, 
Day 700, Day 897, Day 1254, Day 1611, Day 1849, Day 2206, Day 2563, and at the end of the 
study (or Early Termination Visit).  If an assessment is not performed at a visit, attempts should 
be made to perform the assessment at the subsequent dosing visit(s) until completed; however, 
an assessment should not be performed more than once at any visit. 
After the ECG is completed, an initial local read of the ECG should occur before the ECG is sent 
for central read (all ECGs will be centrally read).  If the subject’s initial ECG results show a QTc 
interval of ≥500 ms, then the ECG should be repeated (prior to the subject leaving the visit).  If 
the second ECG QTc again reads ≥500 ms, the physician should use his or her best clinical 
judgement to address the condition. 
Additional ECGs may be performed per the judgement of the Investigator, as deemed clinically 
necessary. 
14.1.3. 
Echocardiograms  
At the time of the implementation of Protocol Version 7, echocardiograms will be performed for 
all subjects at Days 1849, 2206, 2563, and at the end of the study (or Early Termination Visit).  
Echocardiograms will only be assessed locally at the site as per local practice.  If an assessment 
is not performed at a visit, attempts should be made to perform the assessment at the subsequent 
dosing visit(s) until completed; however, an assessment should not be performed more than once 
at any visit. 
14.1.4. 
Physical Examinations 
Physical examinations will be performed for all subjects at every onsite visit throughout the 
study.  Any abnormal findings observed during physical examinations will be captured as AEs 
and reported according to Section 15. 
Videotaping of the physical examinations will be optional. 
14.1.5. 
Vital Signs 
Vital signs include resting systolic and diastolic blood pressure, pulse rate, respiratory rate, and 
temperature.  Additionally, pulse oximetry will be collected.  From Screening through Day 779, 
vital signs and pulse oximetry will be collected predose and at 4 timepoints postdose:  1, 2, 4, 
and 6 hours.  From Day 897 through Day 2891, vital signs and pulse oximetry will be taken 
predose and approximately 1 hour postdose (±15 minutes) at every onsite visit throughout the 
study.   
14.2. 
Laboratory Safety Assessments 
Laboratory measurements of serum chemistry, hematology, urinalysis, and urine total protein 
will be collected at Screening, Day 15, Day 29, and every 4 months thereafter (i.e., Days 64, 183, 

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302, 421, 540, 659, 778, 897, 1016, 1135, 1254, 1373, 1492, 1611, 1730, 1849, 1968, 2087, 
2206, 2325, 2444, 2563, 2682, and 2801), as well as on Day 365, Day 700, and Day 2891 (End 
of Study)/Early Termination Visit.  The laboratory analytes to be measured are shown in 
Appendix A.  Quantitative urine total protein will be assessed at the local laboratory. For urinary 
protein concentration >0.2 g/L, repeat testing and further evaluation should be considered; 
quantitative urine total protein should be prioritized if there is not enough urine sample for all 
tests. 
Due to blood collection volume limitations for newborns, the laboratory safety assessments 
described above will be performed according to the schedules listed in Table 8 and Table 9.  
Coagulation testing was not performed at every visit in previous versions of the protocol 
(Versions 1 through 5); therefore not all subjects will have coagulation results prior to all doses 
received during this timeframe.  At the time of implementation of Protocol Version 6, 
coagulation testing was added, was to be conducted at each visit, and results were required to be 
reviewed prior to dosing.   Coagulation testing will continue to be conducted at each visit or up 
to 7 days prior to dosing and results should be reviewed prior to dosing.  In situations where 
predose verification of coagulation laboratory results is not feasible or optimal (e.g., prolonged 
sedation of the subject would be required to allow adequate time for lab processing), the 
Investigator may exercise discretionary clinical judgment and proceed with the LP procedure, 
based on the subject’s clinical and coagulation lab history.   
Table 8: 
Laboratory Safety Blood Collection Schedule for Subjects with a Screening 
Weight of ≥3 kg 
Panel/Test 
Screening1 Day 
1 
Day 
15 
Day 
29 
Day 
64 
Days 183, 302, 
421, 540, 659, 
778 (±14D) 
Days 365, 700, 897, 1016, 
1135, 1254, 1373, 1492, 
1611, 1730, 1849, 1968, 
2087, 2206, 2325, 2444, 
2563, 2682, 2801, 2891 
(±14D), and Early Term 
Hematology 
X 
 
X 
X 
X 
X 
X 
Serum 
Chemistry 
X 
 
X 
X 
X 
X 
X 
Cystatin C 
X 
 
 
 
X2 
X2 
X 
Coagulation 
X 
X 
X 
X 
X 
X 
X 
D = day(s); Term = termination. 
1 Screening laboratory tests will be collected over a two or more day period. 
2 At Day 183 or when the subject’s weight is ≥5.4 kg, whichever comes first, the blood collection schedule will 
revert to that outlined in Section 5. 
 
 
 

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Table 9: 
Laboratory Safety Blood Collection Schedule for Subjects with a Screening 
Weight of <3 kg 
Panel/Test 
Screening1 Day 
1 
Day 
15 
Day 
29 
Day 
64 
Days 183, 
302, 421, 540, 
659, 778 
(±14D) 
Days 365, 700, 897, 1016, 
1135, 1254, 1373, 1492, 
1611, 1730, 1849, 1968, 
2087, 2206, 2325, 2444, 
2563, 2682, 2801, 2891 
(±14D), and Early Term 
Hematology 
X 
 
X 
X 
X 
X 
X 
Serum 
Chemistry 
X 
 
X 
X 
X 
X 
X 
Coagulation 
X 
X 
X 
X 
X 
X 
X 
D = day(s); Term = termination. 
1 Screening laboratory tests will be collected over a two or more day period. 
 

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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 subject.  If necessary, 
appropriate medical intervention should be provided. 
At the signing of the ICF, each subject’s legally authorized representative(s) and/or main 
caregiver(s) 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 subject 
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. 
Determination of whether an abnormal laboratory value, vital sign result, and/or ECG result 
meets the definition of an AE will be made by the Investigator.  Abnormal results are not 
considered AEs unless 1 or more of the following criteria are met: 
• The result meets the criteria for an SAE 
• The result requires the subject to receive specific corrective therapy 
• The result is considered by the Investigator 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 subject 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 

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• Is a medically important event 
A medically important event is an AE that, in the opinion of the Investigator, may jeopardize the 
subject or may require intervention to prevent one of the other outcomes 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 will not be considered 
an SAE, even if the subject 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 subject’s 
parent(s)/legal guardian(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 subject’s parent(s)/legal guardian(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. 
o If a subject 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 and the LP procedure as defined in 
Section 15.2.2 
• The severity of the event as defined in Section 15.2.3 
15.2.2. 
Relationship of Events to Study Treatment or Lumbar Puncture Procedure 
The following definitions should be considered when evaluating the relationship of AEs and 
SAEs to the study treatment: 

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Relationship of Event to Study Treatment 
Related 
There is clear evidence that the event is related to the use of the investigational drug 
(e.g., confirmation by positive re-challenge test). 
Possible 
The event cannot be explained by the subject’s medical condition, concomitant therapy, 
or other causes, and there is a plausible temporal relationship between the event and 
administration of the investigational drug. 
Unlikely/ 
Remote 
An event for which an alternative explanation is more likely (e.g., concomitant 
medications or ongoing medical conditions) or the temporal relationship to 
investigational drug administration and/or exposure suggests that a causal relationship 
is unlikely.  (For reporting purposes, Unlikely/Remote will be grouped together with 
Not Related.) 
Not Related 
The event can be readily explained by the subject’s underlying medical condition, 
concomitant therapy, or other causes, and therefore, the Investigator believes no 
relationship exists between the event and the investigational drug. 
The following definitions should be considered when evaluating the relationship of AEs and 
SAEs to the LP procedure: 
Relationship of Event to LP Procedure 
Related 
There is clear evidence that the event is related to the LP procedure (e.g., bleeding from 
the puncture site). 
Possible 
The event cannot be explained by the subject’s medical condition, concomitant therapy, 
or other causes, and there is a plausible temporal relationship between the event and the 
LP procedure. 
Unlikely/ 
Remote 
An event for which an alternative explanation is more likely (e.g., concomitant 
medications or ongoing medical conditions) or the temporal relationship to the LP 
procedure suggests that a causal relationship is unlikely.  (For reporting purposes, 
Unlikely/Remote will be grouped together with Not Related.) 
Not Related 
The event can be readily explained by the subject’s underlying medical condition, 
concomitant therapy, or other causes, and therefore, the Investigator believes no 
relationship exists between the event and the LP procedure. 

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15.2.3. 
Severity of Events 
The following definitions should be considered when evaluating the severity of AEs and SAEs: 
Severity of Event 
Mild 
The event is easily tolerated by the subject and does not affect the subject’s usual daily 
activities. 
Moderate 
The event causes the subject more discomfort and interrupts the subject’s usual daily 
activities. 
Severe 
The event is incapacitating and causes considerable interference with the subject’s 
usual daily activities. 
15.2.4. 
Expectedness of Events 
Expectedness of all AEs will be determined by the Sponsor (or designee) according to the 
Investigator’s Brochure. 
15.3. 
Monitoring and Recording Events 
15.3.1. 
Adverse Events 
For subjects who receive study treatment, any AE experienced between the time of signing the 
ICF and Final Study Visit/Telephone Call is to be recorded on the CRF, regardless of the 
severity of the event or its relationship to study treatment.  At each study visit, the Investigator 
will assess the subject for AEs and will record any new AEs or updates to previously reported 
AEs on the CRF.  Note:  Any new or worsened findings (including signs and symptoms of SMA) 
that start after the informed consent date must be recorded as AEs and should not be listed as 
medical history. 
For subjects who never receive study treatment, no AEs need to be recorded on the applicable 
CRF.   
An AE that is ongoing when the subject completes or discontinues the study should be followed 
by the Investigator, if possible, until the event has resolved or stabilized.   
15.3.2. 
Serious Adverse Events 
For subjects who receive study treatment, any SAE experienced between the time of signing the 
ICF and Final Study Visit/Telephone Call is to be recorded on an SAE form and on the 
applicable CRF, regardless of the severity of the event or its relationship to study treatment.  For 
subjects who never receive study treatment, any SAE occurring between the time of signing the 
ICF and Final Study Visit/Telephone Call must be recorded on an SAE form, regardless of the 
severity of the event or its relationship to study treatment; however, the SAE does not need to be 
recorded on the applicable CRF.   

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SAEs must be reported to the safety vendor listed in the Study Reference Guide within 24 hours 
(as described in Section 15.3.3) or according to national law).  Follow-up information regarding 
an SAE also must be reported within 24 hours. 
Subjects will be followed for all SAEs until their Final Study Visit/Telephone Call.  Thereafter, 
the event should be reported as described in the Study Reference Guide only if the Investigator 
considers the SAE to be related to study treatment. 
Any SAE that is ongoing when the subject 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 the safety contact as described in the Study Reference Guide within 24 hours of 
the study site staff becoming aware of the SAE or according to national law.  It is the 
Investigator’s responsibility to ensure that the SAE reporting information and procedures are 
used and followed appropriately. 
Reporting Information for SAEs 
Any SAE that occurs between the time that the subject’s parent(s)/legal guardian(s) has signed 
the ICF and Final Study Visit/Telephone Call must be reported as described in the Study 
Reference Guide within 24 hours of the study site staff becoming aware of the event.   
A report must be submitted as described in the Study Reference Guide regardless of the 
following: 
• Whether or not the subject has undergone study-related procedures 
• Whether or not subject has received study treatment 
• The severity of the event 
• The relationship of the event to study treatment 
To report initial or follow-up information on an SAE, fax or email a completed SAE form as 
described in the Study Reference Guide. 
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 or according to national law.  The Investigator should make every 
effort to obtain and send death certificates and autopsy reports as described in the Study 

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Reference Guide.  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 
Suspected unexpected serious adverse reactions (SUSARs) are SAEs that are unexpected and 
judged by the Investigator or Sponsor (or designee) to be related to the study treatment 
administered. 
The Sponsor (or designee) will report SUSARs to the appropriate regulatory authorities and 
Investigators as required, according to local law. 
15.4. 
Procedures for Handling Special Situations 
15.4.1. 
Overdose 
All dosing errors (including but not limited to route of administration, wrong dose, etc.) must be 
reported as protocol deviations.  A brief description should be provided in the deviation, 
including whether the subject was symptomatic or not.  Dosing details should be captured on the 
Dosing CRF. 
A dosing error will be considered an overdose when any of the following conditions are met: 
• A dose given exceeds the dose level described in the protocol and Drug Handling 
Guidelines 
• Dosing frequency exceeds 4 doses in a 2-month period (and, thus, results in a higher 
than acceptable cumulative dose) 
• Any time study treatment is administered less than 2 weeks from the previous dose 
Overdoses are not considered AEs and should not be recorded as an AE on the CRF unless an 
AE or an SAE occurs.  All overdoses (regardless of whether or not they result in an AE) must be 
recorded on an overdose form and faxed to the Sponsor (or designee) within 24 hours of the site 
becoming aware of the overdose.  If an overdose results in an SAE, both the SAE and overdose 
forms must be completed and faxed to the Sponsor (or designee).  Should an overdose occur, the 
Investigator or designee must contact the Medical Monitor within 24 hours; refer to the Study 
Reference Guide for the complete contact information. 
15.4.2. 
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. 

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15.5. 
Safety Responsibilities 
15.5.1. 
The Investigator 
The Investigator’s responsibilities include the following: 
• Monitor and record all AEs, including SAEs, on the CRF 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. 
• Complete an SAE form for each SAE and fax it as described in the Study Reference 
Guide within 24 hours of the study site staff becoming aware of the event or 
according to national law. 
• Pursue SAE follow-up information actively and persistently.  Follow-up information 
must be reported as described in the Study Reference Guide within 24 hours of the 
study site staff becoming aware of new information or according to national law. 
• Ensure all AE and SAE reports are supported by documentation in the subjects’ 
medical records. 
• Pursue AE follow-up information, if possible, until the event has resolved or become 
stable.  Record AE follow-up information, including resolution, on the CRF, as 
applicable. 
• Report SAEs to local ethics committees, as required by local law. 
15.5.2. 
The Sponsor 
The Sponsor’s responsibilities include the following: 
• Before study site activation and subject enrollment, the Clinical Monitor (or designee) 
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. 
• The Sponsor (or designee) 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 
In general, continuous variables will be summarized by descriptive statistics, including number, 
mean, median, standard deviation, minimum, and maximum.  Categorical variables will be 
presented with the number and percentage in each category.  
The Full Analysis Set (FAS) is defined as all subjects who receive at least 1 dose of nusinersen. 
The Per-Protocol Set (PPS) will include the subset of the FAS who complete at least the initial 
4 doses of study treatment, have a baseline and at least the Day 183 efficacy assessments, and 
who have no significant protocol deviations that would be expected to affect efficacy 
assessments. 
A number of the endpoints are age-specific and, therefore, over the course of the study as 
subjects get older, different scales will be utilized.  Three baselines will be defined.  The first 
baseline will be defined as the closest available assessment on or prior to Day 1 predose when 
the child is <6 weeks of age.  The second baseline will be defined as on or prior to the Day 700 
visit when the child is approximately 2 years of age.  The third baseline will be defined as on or 
prior to Day 897 predose visit when the child is approximately 2.5 years of age. 
The objectives of the study and the endpoints to be analyzed are listed in Section 6. 
16.1. 
Efficacy 
16.1.1. 
Analysis Population 
The primary analysis of efficacy will be performed on subjects in the FAS with 2 SMN2 copies.  
Analyses will be repeated in the FAS and PPS, as well as in the PPS with 2 SMN2 copies.  For 
the longitudinal analyses of certain endpoints, it may be necessary to define additional efficacy 
sets. 
16.1.2. 
Methods of Analysis 
16.1.2.1. Analysis of the Primary Endpoint 
The primary endpoint is the time to respiratory intervention or death.  An event of respiratory 
intervention will be defined as either invasive or noninvasive ventilation for ≥6 hours/day 
continuously for 7 or more consecutive days OR tracheostomy.  The time will be the age of the 
subject at the first occurrence of either a respiratory intervention or death. 
A Kaplan-Meier survival curve of the time to respiratory intervention or death will be presented 
and used to estimate the median time to event and corresponding 95% confidence interval (CI). 

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16.1.2.2. Analysis of the Secondary Endpoints 
Age:  <6 weeks to 2 years 
During this period, the 13- and 24-Month Visits are of most interest.  The visit at Day 365 will 
be used for the assessment of the endpoint at 13 months and the visit at Day 700 will be used for 
the assessment of the endpoint at 24 months.  The proportion of subjects meeting the criteria for 
the following at the 13- and 24-Month Visits will be presented with a corresponding 95% CI: 
• Clinically manifested SMA defined by any one of the following: 
o If at the 13- or 24-Month Visit, the subject’s weight has dropped below the 
5th percentile according to WHO criteria [WHO 2014]; or if compared to 
Baseline, a subject has decreased ≥2 major weight growth curve percentiles 
(3rd, 5th, 10th, 25th, or 50th) according to WHO criteria; or if a percutaneous 
gastric tube has been required at any point up to and including the 13- or 
24-Month Visit, as documented in the concomitant procedures in the CRF 
o Failure to demonstrate the following as assessed by the WHO motor 
milestones:  
▪ At 13 and 24 months of age:  ability to sit without support, standing 
with assistance, hands-and-knees crawling 
▪ Additionally, at 24 months of age:  walking with assistance, standing 
alone, and/or walking alone  
o Subjects who discontinue or die on or before the 13- or 24-Month Visit 
• Achievement of each individual motor milestone as assessed by the HINE (Section 2) 
and the WHO motor milestones.  Subjects who discontinue prior to the 13- or 
24-Month Visit will be counted in the denominator. 
Age:  2 to 8 years 
During this period, the 2.5, 3, 4, 5, 6, 7, and 8 years of age visits are of the most interest.  The 
Day 897 visit will be used for 2.5 years, Day 1135 will be used for 3 years, Day 1492 will be 
used for 4 years, Day 1849 will be used for 5 years, Day 2206 will be used for 6 years, Day 2563 
will be used for 7 years, and Day 2891 will be used for 8 years. 
The proportion of subjects who have the ability to perform WHO motor milestones at Baseline 
and maintain this ability up to 8 years of age will be summarized by visit. 
The HFMSE total score and change from Baseline will be summarized by visit using descriptive 
statistics. 

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Age:  <6 weeks to 8 years 
A Kaplan-Meier survival curve will be presented and used to estimate the proportion of subjects 
alive at 13 months and 2, 3, 4, 5, 6, 7, and 8 years of age.  Corresponding 95% CIs will also be 
presented. 
• Change from Baseline to each visit will be summarized using descriptive statistics for 
the following growth parameters:  weight for age/length, head circumference, chest 
circumference, head-to-chest circumference ratio, and arm circumference.   
• Change from Baseline to each visit for the CHOP INTEND motor function will be 
summarized using descriptive statistics.  The maintenance of the ability to achieve a 
threshold of total score of ≥50 over time will also be presented. 
• The actual value and change from Baseline in CSF survival protein concentration will 
be summarized. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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16.2. 
Pharmacokinetics 
16.2.1. 
Analysis Population 
The PK analysis will be performed on all subjects for which there is at least 1 evaluable PK 
sample after the first IT injection. 
16.2.2. 
Methods of Analysis 
Results of CSF and plasma nusinersen concentrations will be summarized by sampling time.  A 
noncompartmental analysis will be conducted to estimate the plasma PK parameters of 
nusinersen, if applicable, and summary statistics will be performed. 
 
 
 
 
 
 
 
 
 
  

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16.4. 
Immunogenicity 
16.4.1. 
Analysis Population 
The analysis population for immunogenicity will include all subjects with available 
immunogenicity data. 
16.4.2. 
Methods of Analysis 
If samples are analyzed, descriptive statistics of the incidence of anti-nusinersen plasma antibody 
concentrations will be presented. 
 
 
 
 
 
 
 
 
 
 
16.6. 
Safety 
All AEs, laboratory abnormalities, ECGs, and vital signs will be evaluated for safety. 
16.6.1. 
Analysis Population 
The analysis of safety will be performed on the FAS. 
16.6.2. 
Methods of Analysis 
16.6.2.1. Adverse Events 
The Medical Dictionary for Regulatory Activities will be used to classify AEs. 
All AEs will be analyzed based on the principle of treatment emergence.  An AE will be 
regarded as treatment emergent if it was present prior to the first dose of study treatment and 
subsequently worsened, or was not present prior to the first dose of study treatment but 
subsequently appeared.  The incidence of treatment-emergent AEs will be summarized overall, 
by severity, and by relationship to study treatment.  A subject having the same AE more than 
once will be counted only once in the incidence for that event.  The occurrence of the AE with 
the greatest severity will be used in the calculation of incidence by severity; the occurrence of the 
AE with the strongest relationship to study treatment will be used in the calculation of incidence 
by relationship to study treatment. 

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16.6.2.2. Clinical Laboratory Results 
Clinical laboratory evaluations including hematology, blood chemistry, and urinalysis will be 
summarized using shift tables, presenting changes relative to each parameter’s normal range.  
Summary statistics for actual values and changes from Baseline will also be presented. 
16.6.2.3. Vital Signs 
The analysis of vital signs will focus on clinically relevant abnormalities.  The number and 
percentage of subjects with clinically relevant postbaseline abnormalities will be presented.  
Summary statistics for actual values and change from Baseline will also be presented. 
16.6.2.4. ECGs 
The number and percentage of subjects with shifts from Baseline normal to each of the 
categorical values denoting normal, abnormal, and abnormal (not AE) will be summarized. 
16.6.2.5. Echocardiograms 
The number and percentage of subjects with clinical changes in echocardiogram readings from 
the first assessment will be summarized. 
16.7. 
Interim Analyses 
Interim data analyses may be performed after approximately 10 subjects have been enrolled.  
Further details about these analyses will be described in the Statistical Analysis Plan. 
16.8. 
Sample Size Considerations 
There are no formal sample size calculations for this study.  Sample size is based upon 
feasibility. 

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17. 
ETHICAL REQUIREMENTS 
The Sponsor and the Investigator must comply with all instructions, regulations, and agreements 
in this protocol and applicable International Council on Harmonisation (ICH) and Good Clinical 
Practice (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.  The Investigator 
is responsible for supervising those individuals and for implementing procedures to ensure the 
integrity of the tasks performed and any data generated. 
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.  The Sponsor (or designee) will submit documents 
on behalf of the investigational sites in countries other than the US.  
If the Investigator makes any changes to the ICF, the Sponsor (or designee) must approve the 
changes before the ICF is submitted to the ethics committee.  A copy of the approved ICF must 
be provided to the Sponsor (or designee).  After approval, the ICF must not be altered without 
the agreement of the relevant ethics committee and the Sponsor (or designee). 
It is the responsibility of the Investigator(s) to ensure that all aspects of institutional review are 
conducted in accordance with current applicable regulations. 
The Sponsor (or designee) 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 the Sponsor (or designee). 
17.3. 
Subject 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 

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subject’s legally authorized representative(s) (e.g., parent[s] or legal guardian[s]) 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 subject must be explained to the subject’s legally 
authorized representative(s).  The subject’s legally authorized representative(s) must be given 
sufficient time to consider whether the subject will participate in the study. 
A copy of the signed and dated ICF must be given to the subject’s legally authorized 
representative(s).  The original 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 subject’s medical record. 
17.4. 
Subject Data Protection 
Prior to any testing under this protocol, including screening tests and assessments, the subject’s 
legally authorized representative(s) must also provide all authorizations required by local law 
(e.g., Protected Health Information authorization in North America). 
During the study, participants’ race and ethnicity and full date of birth 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. 
SMA is caused by the loss of SMN protein due to a homozygous deletion or mutation or a 
compound heterozygous mutation in the SMN1 gene on chromosome 5q11-q13.  Thus, patients 
with SMA are completely dependent on the amount of SMN protein produced by the SMN2 
gene.  Genetic modifiers, such as the number of copies of the SMN2 gene, are known to impact 
the eventual phenotype of SMA.  The incidence and prevalence of SMA and its subtypes have 
been reported to vary based on country.  One hypothesis for these variances is a difference in the 
frequency of certain genetic mutations that may be associated with different racial and ethnic 
groups within each country.  Therefore, the race/ethnicity of participants will be collected as part 
of the medical history, where local regulations allow.  The full date of birth is needed in order to 
precisely calculate the age at achievement of motor milestones and the weight-for-age 
percentiles. 
Study reports will be used for research purposes only.  The subject will not be identified by name 
in the CRFs, study-related forms, study reports, or any related publications.  The Sponsor, 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 subject’s personal medical data 
confidential. 

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17.5. 
Compensation for Injury 
The Sponsor (or designee) 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 the 
Sponsor or its partners) with the subject’s legally authorized representative(s) before the 
subject’s legally authorized representative(s) makes a decision for the subject to participate in the 
study. 
17.7. 
Registration of Study and Disclosure of Study Results 
The Sponsor (or designee) 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 subjects prior to completion of a study initiation visit 
conducted by the Sponsor (or designee).  This initiation visit will include a detailed review of the 
protocol and study procedures. 
18.2. 
Quality Control and Quality Assurance 
Quality control procedures will be implemented at each stage of data handling to ensure that all 
data are reliable and have been processed correctly.  Data anomalies will be communicated to the 
sites for clarification and resolution, as appropriate. 
During and/or after completion of the study, quality assurance officers named by the Sponsor or 
the regulatory authorities may wish to perform onsite audits or inspections.  The Investigator will 
be expected to cooperate with any audit 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 subjects’ 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(s) will visit the Investigator(s) at regular intervals during the study and 
after the study has completed, as appropriate.  A clinical site monitoring plan will detail who 
performs the monitoring, how often it is performed, and the extent of review.  It will also provide 
the monitoring strategy, with emphasis on subject safety, data integrity, and critical data and 
processes. 
During these visits, CRFs and supporting documentation related to the study will be reviewed 
and any discrepancies or omissions will be resolved. 
Monitoring visits must be conducted according to the applicable ICH and GCP guidelines to 
ensure the protection of subject rights and well-being, protocol adherence, quality of data 
(accurate, complete, and verifiable), study treatment accountability, compliance with regulatory 
requirements, and continued adequacy of the investigational site and its facilities. 
18.4. 
Study Funding 
Biogen is funding the study.  Biogen is the Sponsor of the study globally.  Biogen (or designee) 
will be responsible for managing the study globally.  All financial details are provided in the 
separate contract(s) between the institution, Investigator, and the Sponsor.   

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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. 
External Contract Organizations 
The Sponsor may transfer any or all of its study-related responsibilities to a contract research 
organization (CRO) and other third parties; however, the Sponsor retains overall accountability 
for these activities. 
19.1.1. 
Contract Research Organization  
A CRO will be responsible for administrative aspects of the study including, but not limited to, 
study initiation, monitoring, and management of SAE reports and data management.  Before 
subjects are screened at each study site, the CRO will review study responsibilities with the 
Investigators and other study site staff, as appropriate. 
19.1.2. 
Interactive Response Technology 
IRT will be used in this study.  Before subjects are screened or enrolled, the IRT vendor will 
provide each study site with the necessary training, a user manual, and access rights to the 
system. 
19.1.3. 
Electronic Data Capture 
Subject information will be captured and managed by study sites on electronic CRFs by a 
Web-based electronic data capture tool that is supported by a vendor and configured by the 
Sponsor or CRO. 
19.1.4. 
Central Laboratories for Laboratory Assessments 
A central laboratory will be selected by the Sponsor to analyze all hematology, blood chemistry, 
urine, and CSF samples collected at all study sites.  Local laboratories may be used to 
accommodate acute or urgent needs as discussed in in the Study Reference Guide. 
During the Screening Period, a blood sample will be collected for SMN2 copy number analysis 
by the central laboratory only from those subjects without genetic documentation of SMN2 copy 
number.  For all other subjects, a blood sample will be collected at any time during the study for 
analysis of SMN2 copy number by the central laboratory. 
19.2. 
Study Committees 
Safety data will be reviewed on an ongoing basis by the Sponsor and the Medical Monitor.  The 
Sponsor and Medical Monitor will review safety, tolerability, and efficacy (as needed) data 
collected on nusinersen during this study. 

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19.3. 
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 subject 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, the Sponsor (or designee) may, at any time, amend this protocol to eliminate an 
apparent immediate hazard to a subject.  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 
Sections 17.2 and 17.3). 
19.4. 
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. 
19.5. 
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 the Sponsor in writing and 
receive written authorization from the Sponsor to destroy study records.  In addition, the 
Investigator must notify the Sponsor 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. 
19.6. 
Study Report Signatory 
The Sponsor will follow all applicable local regulations pertaining to study report signatories. 

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20. 
REFERENCES 
 
 
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Burghes AH, Beattie CE. Spinal muscular atrophy: why do low levels of survival motor neuron 
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Chien YH, Lee NC, Thurberg BL, et al. Pompe disease in infants: improving the prognosis by 
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Coovert DD, Le TT, McAndrew PE, et al. The survival motor neuron protein in spinal muscular 
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Dubowitz L, Dubowitz V. The neurological assessment of the preterm and full-term newborn 
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real-time lightCycler PCR: fast and highly reliable carrier testing and prediction of severity of 
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Finkel RS, Mercuri E, Meyer OH, et al. Diagnosis and management of spinal muscular atrophy: 
Part 2: Pulmonary and acute care; medications, supplements and immunizations; other organ 
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Geary RS, Yu RZ, Watanabe T, et al. Pharmacokinetics of a tumor necrosis factor-alpha 
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Glanzman AM, Mazzone E, Main M, et al. The Children's Hospital of Philadelphia Infant Test of 
Neuromuscular Disorders (CHOP INTEND): test development and reliability. Neuromuscul 
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Glanzman AM, McDermott MP, Montes J, et al. Validation of the Children's Hospital of 
Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND). Pediatr Phys Ther. 
2011;23(4):322-6. 

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Haataja L, Mercuri E, Regev R, et al. Optimality score for the neurologic examination of the 
infant at 12 and 18 months of age. J Pediatr. 1999;135(2 Pt 1):153-61. 
Helmken C, Hofmann Y, Schoenen F, et al. Evidence for a modifying pathway in SMA 
discordant families: reduced SMN level decreases the amount of its interacting partners and 
Htra2-beta1. Hum Genet. 2003;114(1):11-21. 
Henry S, Stecker K, Brooks D, et al. Chemically modified oligonucleotides exhibit decreased 
immune stimulation in mice. J Pharmacol Exp Ther. 2000;292(2):468-79. 
Hua Y, Vickers TA, Baker BF, et al. Enhancement of SMN2 exon 7 inclusion by antisense 
oligonucleotides targeting the exon. PLoS Biol. 2007;5(4):e73. 
Hua Y, Vickers TA, Okunola HL, et al. Antisense masking of an hnRNP A1/A2 intronic splicing 
silencer corrects SMN2 splicing in transgenic mice. Am J Hum Genet. 2008;82(4):834-48. 
 
 
 
Jedrzejowska M, Milewski M, Zimowski J, et al. Incidence of spinal muscular atrophy in 
Poland--more frequent than predicted? Neuroepidemiology. 2010;34(3):152-7. 
Keren H, Lev-Maor G, Ast G. Alternative splicing and evolution: diversification, exon definition 
and function. Nat Rev Genet. 2010;11(5):345-55. 
Le TT, Pham LT, Butchbach ME, et al. SMNDelta7, the major product of the centromeric 
survival motor neuron (SMN2) gene, extends survival in mice with spinal muscular atrophy and 
associates with full-length SMN. Hum Mol Genet. 2005;14(6):845-57. 
Lefebvre S, Bürglen L, Reboullet S, et al. Identification and characterization of a spinal muscular 
atrophy-determining gene. Cell. 1995;80(1):155-65. 
Lefebvre S, Burlet P, Liu Q, et al. Correlation between severity and SMN protein level in spinal 
muscular atrophy. Nat Genet. 1997;16(3):265-9. 
 
 
Lorson CL, Hahnen E, Androphy EJ, et al. A single nucleotide in the SMN gene regulates 
splicing and is responsible for spinal muscular atrophy. Proc Natl Acad Sci U S A. 
1999;96(11):6307-11. 
Main M, Kairon H, Mercuri E, et al. The Hammersmith functional motor scale for children with 
spinal muscular atrophy: a scale to test ability and monitor progress in children with limited 
ambulation. Eur J Paediatr Neurol. 2003;7(4):155-9. 

Protocol 232SM201 
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Presymptomatic SMA Study 
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85 
 
 
 
 
 
McKay RA, Miraglia LJ, Cummins LL, et al. Characterization of a potent and specific class of 
antisense oligonucleotide inhibitor of human protein kinase C-alpha expression. J Biol Chem. 
1999;274(3):1715-22. 
Mercuri E, Finkel RS, Muntoni F, et al. Diagnosis and Management of Spinal Muscular Atrophy: 
Part 1: Recommendations for Diagnosis, Rehabilitation, Orthopedic and Nutritional Care. 
Neuromuscul Disord. 2018;28(2):103-115. Epub 2017/11/23. 
Monani UR, Lorson CL, Parsons DW, et al. A single nucleotide difference that alters splicing 
patterns distinguishes the SMA gene SMN1 from the copy gene SMN2. Hum Mol Genet. 
1999;8(7):1177-83. 
 
 
O'Hagen JM, Glanzman AM, McDermott MP, et al. An expanded version of the Hammersmith 
Functional Motor Scale for SMA II and III patients. Neuromuscul Disord. 2007;17(9-10):693-7. 
Passini MA, Bu J, Richards AM, et al. Antisense oligonucleotides delivered to the mouse CNS 
ameliorate symptoms of severe spinal muscular atrophy. Sci Transl Med. 2011;3(72):72ra18. 
Prior TW. Perspectives and diagnostic considerations in spinal muscular atrophy. Genet Med. 
2010;12(3):145-52. 
Prior TW, Swoboda KJ, Scott HD, et al. Homozygous SMN1 deletions in unaffected family 
members and modification of the phenotype by SMN2. Am J Med Genet A. 2004;130A(3):307-
10. 
 
 
Sugarman EA, Nagan N, Zhu H, et al. Pan-ethnic carrier screening and prenatal diagnosis for 
spinal muscular atrophy: clinical laboratory analysis of >72,400 specimens. Eur J Hum Genet. 
2012;20(1):27-32. 
Swoboda KJ, Prior TW, Scott CB, et al. Natural history of denervation in SMA: relation to age, 
SMN2 copy number, and function. Ann Neurol. 2005;57(5):704-12. 
Tassie B, Isaacs D, Kilham H, et al. Management of children with spinal muscular atrophy type 1 
in Australia. J Paediatr Child Health. 2013;49(10):815-9. 

Protocol 232SM201 
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Presymptomatic SMA Study 
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86 
 
 
 
 
 
 
 
WHO. WHO Child Growth Standards. WHO Website. Published 2014.  
WHO Multicentre Growth Reference Study Group. Assessment of sex differences and 
heterogeneity in motor milestone attainment among populations in the WHO Multicentre Growth 
Reference Study. Acta Paediatr Suppl. 2006;450:66-75. 
Wijnhoven TM, de Onis M, Onyango AW, et al. Assessment of gross motor development in the 
WHO Multicentre Growth Reference Study. Food Nutr Bull. 2004;25(1 Suppl):S37-45. 
Wirth B, Brichta L, Schrank B, et al. Mildly affected patients with spinal muscular atrophy are 
partially protected by an increased SMN2 copy number. Hum Genet. 2006;119(4):422-8. 
 

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21. 
APPENDICES 

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APPENDIX A. 
LABORATORY ANALYTES 
Clinical Safety Assessments (minimum requirements) 
Other Assessments 
Clinical Chemistry 
Sodium 
Potassium 
Chloride 
Total protein 
Albumin 
Calcium 
Phosphorus 
Bicarbonate 
Glucose 
BUN 
Creatinine 
Cystatin C (for subjects 
with Screening weight of 
≥3 kg) 
Total serum bilirubin 
(direct and indirect) 
Alkaline phosphatase 
AST (SGOT) 
ALT (SGPT) 
CPK 
GGT 
Urinalysis 
Specific gravity 
pH 
Protein 
Glucose 
Ketones 
Bilirubin 
Blood 
Red blood cells 
WBCs 
Epithelial cells 
Bacteria 
Casts 
Crystals 
Leukocyte esterase 
 
Hematology 
Red blood cells 
Hemoglobin 
Hematocrit 
Platelets 
WBCs 
WBC differential (% and absolute) 
• 
Neutrophils 
• 
Eosinophils 
• 
Basophils 
• 
Lymphocytes 
• 
Monocytes 
PK 
CSF and plasma nusinersen levels 
 
 
 
 
 
 
 
 
 
Immunogenicity Evaluation 
Plasma anti-nusinersen Abs 
 
The following are to be assessed by 
local laboratory only 
Urine total protein1 
Coagulation (aPTT, PT, and INR) 
ALT = alanine aminotransferase; aPTT = activated partial thromboplastin time; AST = aspartate aminotransferase; 
BUN = blood urea nitrogen; CPK = creatine phosphokinase; CSF = cerebrospinal fluid; DNA = deoxyribonucleic 
acid; GGT = gamma-glutamyl transferase; INR = international normalized ratio; PK = pharmacokinetic(s); 
PT = prothrombin time; RNA = ribonucleic acid; SGOT = serum glutamic-oxaloacetic transaminase; 
SGPT = serum glutamic-pyruvic transaminase; 
; WBC = white blood cell.  
1 Quantitative urine total protein should be prioritized if there is not enough urine sample for all tests.  For urinary 
protein concentration >0.2 g/L, repeat testing and further evaluation should be considered. 

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22. 
SIGNED AGREEMENT OF THE STUDY PROTOCOL 
I have read the foregoing protocol, “An Open-Label Study to Assess the Efficacy, Safety, 
Tolerability, and Pharmacokinetics of Multiple Doses of ISIS 396443 Delivered Intrathecally to 
Subjects With Genetically Diagnosed and Presymptomatic Spinal Muscular Atrophy,” 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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Biogen MA Inc. 
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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 232SM201 
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy 
Version 9 
Date: 17 October 2021 
EUDRA CT Number: 2014-002098-12 
Version 9 of the protocol has been prepared for this amendment, which supersedes Version 8. 
 
 

Amendment Summary for Protocol 232SM201, Version 9 
 
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Biogen MA Inc. 
2 
PRIMARY REASON FOR AMENDMENT 
The primary reason for this amendment to Protocol 232SM201 is to limit the number of 
participants who are receiving nusinersen concomitantly with other SMA therapies to 20% 
(n = 5) of the total population. 
New text is shown in bold type; deleted text is shown with a strikethrough. 
Section 11.5.1.1, Allowed Concomitant Therapy 
Now reads:  
Concomitant therapies may be used at the discretion of the Investigator. 
Any concomitant medications including SMA therapies will be captured in the CRF.  
Approved concomitant therapies may be used at the discretion of the Investigator. 
With implementation of Protocol Version 9, Investigators with participants newly seeking 
combination therapy with other SMA therapies should consult and obtain approval from 
the Medical Monitor. This will be permitted for country-approved SMA therapies if the 
total number of study participants concurrently receiving nusinersen and other SMA 
therapies has not yet reached 20% of all enrolled participants.  This is consistent with 
primary and secondary objectives of this study.  Any participants already receiving 
combination therapy with other SMA therapies at the time of Protocol Version 9 
implementation may continue this combination therapy regardless of the 20% limit. 
Rationale: The primary objective of this study is to examine the efficacy of multiple doses of 
nusinersen administered IT in preventing or delaying the need for respiratory intervention or 
death in infants with genetically diagnosed and presymptomatic SMA. The secondary objectives 
of this study are to examine the effects of nusinersen in infants with genetically diagnosed and 
presymptomatic SMA on the development of clinically manifested SMA as determined by a 
composite of clinical features seen in subjects with SMA; growth and function; and safety, 
tolerability, and PK. Limiting the total number of participants who are being treated concurrently 
with nusinersen and other SMA therapies is consistent with evaluating the primary and 
secondary objectives of the study in subjects receiving only nusinersen. In addition, limiting the 
total number of participants who are being treated concurrently with nusinersen and other SMA 
therapies will maintain the intent of the EU postauthorization commitment to evaluate the 
long-term safety and efficacy of nusinersen. 
This change also affects Section 11.5.1.2 (Disallowed Concomitant Therapy).   

Amendment Summary for Protocol 232SM201, Version 9 
 
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5 
Rationale: This change clarifies that the neurological examinations can be done along with other 
predose assessments. 
This change also affects Sections 14.1 (Clinical Safety Assessments) and 14.1.1 (Neurological 
Examinations). 
 
Section 5.2, Table 3, Schedule of Activities: Day 897 Through Day 1730; and Table 4, Schedule 
of Activities: Day 1849 Through Day 2891 (End of Study) 
Change: Footnote 5 of Table 3 and footnote 7 (now footnote 8) of Table 4 were revised to 
provide details on prioritization of urinalysis tests in the event there is not enough sample for all 
tests. 
Now reads (both footnotes): 
Among the laboratory measurements, quantitative urine total protein will be assessed at the local 
laboratory.  If urinary protein concentration is >0.2 g/L, repeat testing and further evaluation 
should be considered; quantitative urine total protein should be prioritized if there is not 
enough urine sample for all tests. 
Rationale: The new footnote text is currently included as a footnote to Appendix A (Laboratory 
Analytes) and is added to the schedule of activity tables for clarity.  
This change also affects Section 14.2 (Laboratory Safety Assessments). 
 
Section 5.2, Table 3, Schedule of Activities: Day 897 Through Day 1730; and Table 4, Schedule 
of Activities: Day 1849 Through Day 2891 (End of Study) 
Change: Footnote 6 of Table 3 and footnote 8 (now footnote 9) of Table 4 were revised to 
clarify the requirement that coagulation testing results must be reviewed prior to dosing.  
Now reads (both footnotes): 
Coagulation testing will be conducted up to 7 days prior to dosing at the time of the 
implementation of Protocol Version 7, and results must be reviewed prior to dosing. 
Coagulation testing will continue to be conducted at each visit or up to 7 days prior to 
dosing and results should be reviewed prior to dosing. In situations where predose 
verification of coagulation laboratory results is not feasible or optimal (e.g., prolonged 
sedation of the subject would be required to allow adequate time for lab processing), the 
Investigator may exercise discretionary clinical judgment and proceed with the LP 
procedure, based on the subject’s clinical and coagulation lab history. 

Amendment Summary for Protocol 232SM201, Version 9 
 
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Now reads: 
Subjects who discontinue treatment will continue follow-up (i.e., regular study visits, but with no 
postdose safety monitoring visits) complete an early termination visit 4 months (+ 14 days) 
after administration of the last dose of nusinersen, unless consent is withdrawn (see 
Section 10.2). If subjects or their parent(s)/caregiver(s) are unable to come for study visits, the 
minimum requirement for follow up (i.e., site visits or telephone calls to the subject’s parent or 
caregiver) should be documented in the source document. 
Rationale: These changes are consistent with the rationale of this study to assess long-term 
safety, efficacy, and tolerability of nusinersen. Additional follow-up beyond 4 months for 
collection of safety assessments in subjects who discontinued nusinersen is no longer required.  
 
Section 11.2, Modification of Dose and/or Treatment Schedule 
Change: Text was revised to indicate that in case of a delayed or missed dose, an adjustment in 
dosing schedule was allowed in the event of unique circumstances, including those related to the 
COVID-19 pandemic, and details regarding recommended dosing administration are provided in 
the DHA. 
Now reads: 
No adjustment of dose is permitted.  If dosing does not occur as per the schedule of activities, 
a protocol deviation must be logged. In the event of delayed or missed doses due to, for 
example, a concurrent illness or other circumstance (e.g., COVID-19 pandemic), the 
Investigator should refer to the DHA which includes recommended dosing administration 
in the event of delayed or missed doses. that would prevent the dosing procedure from being 
performed safely, an adjustment in the dose schedule may be permitted but must be approved by 
the Medical Monitor. 
Rationale: Text was revised to broaden the circumstances in which delayed or missed doses may 
have occurred and to allow adjustment to the dose schedule.  
 
Section 11.6, Continuation of Treatment 
Change: Text describing an extension study was deleted. 
Now reads: 
11.6 
Continuation of Treatment 
Subjects who continue in the study until Day 2891 will be offered the option to enter an 
extension study (under a separate protocol) if they meet all of the inclusion and exclusion 

Amendment Summary for Protocol 232SM201, Version 9 
 
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Biogen MA Inc. 
9 
race/ethnicity of participants will be collected as part of the medical history, where local 
regulations allow.  The full date of birth is needed in order to precisely calculate the age at 
achievement of motor milestones and the weight-for-age percentiles. 
Rationale: Race and ethnicity data can be collected, provided it is noted in the protocol; 
therefore, this text has been added for indicate that these parameters will be collected to be used 
in the analysis of the safety and/or PK profile of nusinersen.  
 

Amendment Summary for Protocol 232SM201, Version 9 
 
CONFIDENTIAL 
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Biogen MA Inc. 
10 
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. 
• The Biogen Development Unit Head signatory was updated. 
• Text added during Protocol Version 7 regarding extending the study was revised to 
past tense.  
• Minor text clarifications were made to the synopsis (Study Design and Duration of 
Treatment and Follow-up). 
• Background information on SMA, current therapies for SMA, and the clinical 
experience with nusinersen were updated. 
• In Section 12, the statement “The DHA supersedes all other references (e.g., 
protocol)” was updated to, “The DHA aligns with all other references, including the 
protocol,” per updates to the protocol template.  
• In Section 15.3, Monitoring and Recording Events and Section 15.5, Safety 
Responsibilities, language regarding reporting requirements for SAEs was updated to 
include “or according to national law,” in line with the latest protocol template update 
by the Sponsor to accommodate countries that may have different reporting 
requirements. 
• Footnote numbering was updated where applicable. 
• References were updated where applicable. 
 

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 232SM201
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy
Version 8
Date: 12 November 2019
EUDRA CT Number: 2014-002098-12
Version 8 of the protocol has been prepared for this amendment, which supersedes Version 7
dated 02 October 2019.

Protocol 232SM201, Version 8
CONFIDENTIAL
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc.
2
PRIMARY REASON FOR AMENDMENT
The primary reason for this amendment to Protocol 232SM201 is to modify the schedule of 
activities with regard to the collection of cerebrospinal fluid (CSF) samples for pharmacokinetics
(PK) and survival motor neuron (SMN) protein analysis and plasma samples for PK analysis.
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 5.2, Schedule of Activities:  Day 897 Through Day 2891 (End of Study)
Change:  The collection of CSF samples taken predose for PK and SMN protein analysis and 
plasma samples for PK analysis was added at Days 1849, 1968, 2206, 2325, 2563, and 2682.  In 
addition, the footnote for plasma samples for PK analysis was updated to specify that plasma will 
be used to assess 
.
Now reads:

Protocol 232SM201, Version 8
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Table 4:
Schedule of Activities:  Day 1849 Through Day 2891 (End of Study)
Treatment/Follow-Up (Each visit can be ±14 days)
PTFU
Study Day
D1849
D1968
D2087
D2206
D2325
D2444
D2563
D2682
D2801
D2891
(EOS)/
Early 
Term1
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Sibling SMA Data
X
X
X
X
Vital Signs and 
Pulse Oximetry2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Weight
X
X
X
X
X
X
X
X
X
X
Growth 
Parameters3
X4
X4
X4
X
Physical 
Examination
X
X
X
X
X
X
X
X
X
X
Ventilator Use
X
X
X
X
X
X
X
X
X
X
Neurological 
Examination5
X4
X
X4
X
X4
X
X4
X
X4
X
X4
X
X4
X
X4
X
X4
X
X
ECG
X4
X4
X4
X
Echocardiogram
X4
X4
X4
X
Laboratory Safety 
Tests7
X4
X4
X4
X4
X4
X4
X4
X4
X4
X
Coagulation 
Laboratory Tests8
X
X
X
X
X
X
X
X
X
X
Immunogenicity
X4
X4
X4
X4
X4
X4
X4
X4
X4
X
CSF PK 
 
X
X
X
X
X
X
X
X
X
Plasma PK9
X4
X4
X4
X4
X4
X4
X4
X4
X4

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Rationale: The schedule of activities was aligned with the planned sampling schedule at every 
visit.
The change to the collection of CSF samples for PK 
 and plasma 
samples for PK analysis also affected Table 2: Pharmacokinetic Sampling Schedule.  The change 
to the footnote also affected Table 1: Schedule of Activities: Screening Through Day 779 and 
Table 3: Schedule of Activities:  Day 897 Through Day 1730.

Protocol 232SM201, Version 8
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Biogen MA Inc.
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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.

References to “this amendment” were updated. 

Typographical errors and formatting were corrected.

CONFIDENTIAL
The information contained herein may not be used, disclosed, or published without the written consent of 
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 232SM201
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy
Version 7
Date: 02 October 2019
EUDRA CT Number: 2014-002098-12
Version 7 of the protocol has been prepared for this amendment, which supersedes Version 6 
dated 20 March 2017.

Protocol 232SM201, Version 7 
CONFIDENTIAL
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Biogen MA Inc.
3
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 5.2, Schedule of Activities:  Day 897 Through Day 2891 (End of Study)
Change: The scheduled visit period was extended up to 8 years after the first injection of 
nusinersen. Table 3 was revised to present the schedule of activities from Day 897 through Day 
1730. Table 4 was added to present the schedule of activities from Day 1849 through Day 2891 
(end of study).
Now reads:

Protocol 232SM201, Version 7 
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5.2 Schedule of Activities:  Day 897 Through Day 18202891 (End of Study)
Table 3:
Schedule of Activities:  Day 897 Through Day 1820 (End of Study)1730
Treatment/Follow-Up (Each visit can be ±7 14days)
Post-
Treatment 
Follow-Up
Study Day
D897
D1016
D1135
D1254
D1373
D1492
D1611
D1730
D1820
(EOS)/
Early Term
1
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Sibling SMA 
Data
X
X
X
X
Vital Signs and 
Pulse 
Oximetry2 1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Weight
X
X
X
X
X
X
X
X
X
Growth 
Parameters2
X3
X3
X3
X3
X3
X3
X3
X3
X
Physical 
Examination
X
X
X
X
X
X
X
X
X
Ventilator Use
X
X
X
X
X
X
X
X
X
Neurological 
Examination4
X3
X
X3
X
X3
X
X3
X
X3
X
X3
X
X3
X
X3
X
X
ECG
X3
X3
X3
X
Laboratory 
Safety Tests5
X3
X3
X3
X3
X3
X3
X3
X3
X
Coagulation 
X
X
X
X
X
X
X
X
X

Protocol 232SM201, Version 7 
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5
Treatment/Follow-Up (Each visit can be ±7 14days)
Post-
Treatment 
Follow-Up
Study Day
D897
D1016
D1135
D1254
D1373
D1492
D1611
D1730
D1820
(EOS)/
Early Term
1
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Pre
LP
Post
Laboratory 
Tests6
Immunogenicit
y
X3
X3
X3
X3
X3
X3
X3
X3
X
CSF PK
X
X
X
X
X
X
X
X
Plasma PK57
X3
X3
X3
X3
X3
X3
X3
X3
Study 
Treatment 
Injection
X
X
X
X
X
X
X
X
CHOP 
INTEND/
HFMSE68
X3
X3
X3
X3
X
WHO Motor 
Milestones79
X3
X3
X3
X3
X

Protocol 232SM201, Version 7 
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7
57See Table 2 for the detailed PK sampling schedule.
68CHOP INTEND will be assessed in subjects until they have a maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be 
assessed.  All subjects ≥2 years of age will be evaluated using the HFMSE.  See Section 13.1.4 and Section 13.4.2.
79WHO motor milestone assessments will be performed by the Investigator or physical therapist at study visits independently of the assessments made by the 
subject’s caregiver.
 

CONFIDENTIAL
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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 232SM201
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy
Version 6
Date:  20 March 2017
EUDRA CT Number:  2014-002098-12
Version 6 of the protocol has been prepared for this amendment, which supersedes Version 5 
dated 15 December 2016.

Protocol 232SM201, Version 6
CONFIDENTIAL
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen MA Inc.
2
PRIMARY REASON FOR AMENDMENT
The primary reason for this amendment to Protocol 232SM201 is to provide subjects with 
presymptomatic spinal muscular atrophy (SMA) with the opportunity to receive open-label 
nusinersen until subjects are 5 years of age (60 months).
New text is shown in bold type; deleted text is shown with a strikethrough.
Section 4.4, Study Rationale
Now reads:
The study is being extended for the collection of endpoint data in all subjects through 
5 years of age in order to assess the long-term safety, efficacy, and tolerability of 
nusinersen.
Rationale:  The extension of Study 232SM201 will provide subjects with presymptomatic SMA 
who participated in and completed Screening through Day 779 of Study 232SM201 with the 
opportunity to receive nusinersen until subjects are up to 5 years of age (60 months).  The 
extension of the treatment duration will allow the Sponsor to monitor the effect of nusinersen on 
subjects with presymptomatic SMA for a longer period of time.
This change also affects Section 5.1, Schedule of Activities:  Screening Through Day 779; 
Section 7.1, Study Overview; Section 7.2, Overall Study Duration and Follow-Up; Section 7.2.2, 
Treatment; Section 7.2.3, Follow-up; Section 11.1, Regimen; Section 11.6, Continuation of 
Treatment; and led to the creation of Section 5.2, Schedule of Activities:  Day 897 Through Day 
1820 (End of Study).

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Cell phone: 
For urgent medical issues in which the study’s Medical Director should be contacted, 
pPlease refer to the Study Reference GuideManual for complete contact information.
Biogen may transfer any or all of its study-related responsibilities to a contract research 
organization (CRO) and other third parties; however, Biogen retains overall accountability 
for these activities.
Rationale:  Biogen assumed global sponsorship of Study 232SM201.
This change also affects Section 12.1, Nusinersen; Section 15.4.2, Medical Emergency; Section 
18.4, Study Funding; and Section 22, Signed Agreement of the Study Protocol.
Section 4, Introduction
Change:  The introduction was updated to provide the most current background information for 
SMA and the ongoing studies in which nusinersen is being investigated.
Now reads:  
ISIS 396443 is a uniformly modified, 2′-O-(2-methoxyethyl) (2′-MOE), antisense 
oligonucleotide (ASO) drug in development for the treatment of spinal muscular atrophy (SMA) 
due to genetic defects in the survival motor neuron 1 (SMN1) gene.
ASOs are short synthetic strings of nucleotides designed to alter the expression of a targeted 
protein by selectively binding to the ribonucleic acid (RNA) that encodes the targeted protein.  In 
patients with SMA, the number of survival motor neuron 2 (SMN2) gene copies and the resulting 
amount of survival motor neuron (SMN) protein are correlated with disease onset and severity.  
A therapeutic approach predicted to benefit patients with SMA is to increase the levels of 
full-length SMN2 pre-messenger ribonucleic acid (mRNA) by restoring the splicing pattern that 
gives rise to full-length SMN2 mRNA, thus increasing full-length SMN protein levels and SMN 
protein activity.  ISIS 396443 is designed to bind to intron 7 of the SMN2 pre-mRNA, restoring 
the splicing pattern that gives rise to full-length SMN2 mRNA and thus increases full-length 
SMN protein levels (Figure 1).

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Figure 1:
ASO Therapeutic Approach for Treatment of SMA
ASO = antisense oligonucleotide; FL = full-length; mRNA = messenger ribonucleic acid; SMA = spinal muscular 
atrophy; SMN = survival motor neuron; SMN1 = survival motor neuron 1; SMN2 = survival motor neuron 2.
4.1.
Overview of Spinal Muscular Atrophy
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized 
by degeneration of the motor neurons in the anterior horn of the spinal cord, resulting in atrophy 
of the voluntary muscles of the limbs and trunk.  Despite being a rare disease, SMA is one of 
the most common genetic causes of death in infants, with a reported birth prevalence 
ranging from 8.5 to 10.3 per 100,000 live births [Arkblad 2009; Jedrzejowska 2010; Prior 
2010; Sugarman 2012; Tassie 2013].With an incidence of 1:6000 to 1:10,000 live births, SMA 
is the most common genetic cause of infant mortality, and a major cause of childhood morbidity 
due to weakness, in developed countries.  The natural history of SMA includes 4 major 
recognized phenotypes that are dependent on age of onset and achieved motor abilities.  The 
most severe form, Type I SMA (equivalent to infantile-onset SMA), has a disease onset within 
the first few months of life; these children are never able to sit or walk and usually die from 
respiratory failure by 2 years of age.  Patients with Type II SMA are able to sit but never walk 
unaided, with symptoms presenting between 6 and 18 months of age.  Patients with Type III 
SMA are able to sit and walk but may become severely and increasingly disabled.  Patients with 

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Type IV or adult-onset SMA have an age of onset over 18 years and have normal life 
expectancies.
In 95% of patients with SMA, a deletion in the survival motor neuron 1 (SMN1) gene on 
chromosome 5q11-q13 is found, with the remaining 5% attributable to small mutations in 
the same gene [Helmken 2003; Lefebvre 1995].  SMN1 lies in the telomeric portion of an 
inverted duplication of a region of chromosome 5.  The centromeric half of the duplication 
contains a homologous gene named survival motor neuron 2 (SMN2) that differs from 
SMN1 by 5 to 11 nucleotides [Lorson 1999; Monani 1999].  The open reading frames for 
both genes encode proteins with identical amino acid sequences.  Survival motor neuron
(SMN) gene transcripts, similar to most mammalian transcripts, undergo alternative 
splicing in which certain exons are either included or excluded from the mature protein 
coding transcripts [Keren 2010].  In particular, exon 7 of the SMN1 gene is alternatively 
spliced with 90% to 95% of the mature messenger ribonucleic acid (mRNA) transcripts 
derived from the SMN1 gene containing exon 7, and 5% to 10% of transcripts missing 
exon 7.  The transcripts missing exon 7 (often referred to as Δ7) produce a truncated 
protein that is defective and unstable [Cho and Dreyfuss 2010].  One of the 5 to 
11 nucleotide differences between SMN1 and SMN2 is a C to T substitution, which occurs 
in exon 7 of the SMN2 gene resulting in an alternative splicing pattern that favors skipping 
of exon 7.  The result shows that as much as 90% of the transcripts produced from SMN2
are missing exon 7.  The remainder, SMN2 transcripts containing exon 7, produces a full-
length (FL) protein product identical to the SMN1 protein because the C to T substitution 
is silent.  Humans have a variable copy number of the SMN2 gene (0 to 8 copies) [Wirth 
2006]. The number of SMN2 copies and the resulting amount of FL-SMN protein 
expressed in patients with SMA (10% to 40% of normal SMN protein levels) correlate with 
SMA disease severity, thus, SMN2 is a key modifier of disease phenotype [Coovert 1997; 
Feldkötter 2002; Lefebvre 1997; Prior 2004].
SMA is caused by loss of SMN protein due to a homozygous deletion or mutation or compound 
heterozygous mutation in the SMN1 gene on chromosome 5q11-q13.  Humans have a duplication 
of the chromosome region where SMN1 is found, resulting in a second copy of the gene, SMN2.  
In SMN2, a C to T nucleotide substitution in exon 7 results in an alternative splicing event such 
that the majority of transcripts produced (~90%) lack exon 7 and a defective truncated protein is 
produced.  The remainder, SMN2 transcripts containing exon 7, produces a full-length protein 
product identical to the SMN1 protein, since the C to T substitution is silent.  Humans have a 
variable copy number of the SMN2 gene (0 to 8 copies).  The number of SMN2 copies and the 
resulting amount of full-length SMN protein expressed in patients with SMA (10% to 40% of 
normal SMN protein levels) correlate with SMA disease severity, and thus, SMN2 is a key 
modifier of disease phenotype [Coovert 1997; Feldkötter 2002; Lefebvre 1997; Prior 2004].
4.2
Current Therapies for Spinal Muscular Atrophy
Nusinersen, also referred to as ISIS 396443 or Spinraza™, has been approved in the United 
States in December 2016 for the treatment of SMA in pediatric and adult patients.  Current 
medical care is supportive and focused on respiratory support, nutritional support, and 

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management of resulting musculotendinous contractures and neuromuscular scoliosis 
through bracing, physical therapy, and surgery [Wang 2007].
There are currently no approved therapies for SMA.  Current medical care is supportive and 
focused on respiratory support, nutritional support, and management of resulting 
musculotendinous contractures and neuromuscular scoliosis through bracing, physical therapy, 
and surgery [Wang 2007].
4.3
Nusinersen
4.3.1
Mechanism of Action
Nusinersen is a fully modified, 2′-O-(2-methoxyethyl) [2′-MOE] chimeric antisense 
oligonucleotide (ASO) drug designed to bind to a specific sequence in the intron 
downstream of exon 7 of the SMN2 gene transcript.  The region of the pre-mRNA targeted 
by nusinersen is normally occupied by heterogeneous nuclear ribonucleoproteins (hnRNP) 
A1/2 proteins, masking the U1 small nuclear ribonucleic acid (snRNA) binding site at the 
5′-exon-intron junction of exon 7.  U1 snRNA base pairs to the sequences that define the 
5′-splice site, which is thought to be one of the first steps that initiate splicing of an intron.  
Nusinersen displaces the hnRNP A1/2 proteins from the pre-mRNA binding site, allowing 
U1 snRNA to bind to the exon-intron junction and promote assembly of the spliceosomal 
complex, thus promoting inclusion of exon 7 into the mRNA, which results in production of 
FL-SMN protein. 
4.3.2
Chemistry
Chemically, nusinersen is a synthetic oligomer of 18 nucleotides (i.e., an 18-mer) that are 
connected sequentially by phosphorothioate linkages.  Each of the 17 internucleotide 
linkages is a 3′-O to 5′-O phosphorothioate diester.  The 18 sugar residues are uniformly 
modified with 2′-MOE).  These MOE-modified nucleotides (1) increased affinity to the 
target mRNA [McKay 1999], (2) increased resistance to exonucleases and endonucleases 
(thereby increasing stability in tissue) [Geary 2003], and (3) ameliorated some of the 
high-dose toxicities associated with ASO containing only the phosphorothioate linkages 
[Henry 2000].
The sequence of nusinersen is written as follows:
5′ -MeUMeCAMeCMeUMeUMeUMeCAMeUAAMeUGMeCMeUGG- 3ʹ
where A and G are 2′-MOE nucleosides, MeC is 5-methyl-2′-MOE cytidine, 
and MeU designates 5-methyl-2′-MOE uridine.
4.3.4
Clinical Experience
NusinersenISIS 396443 has been evaluated in a completed open-label, single-ascending-dose, 
Phase 1 study designed to assess the safety, tolerability, and PK of nusinersenISIS 396443 in 

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subjects with SMA (ISIS 396443-CS1).  A single dose of nusinersenISIS 396443 was 
administered by IT injection to subjects 2- to 14-year-old subjects with SMA 2 to 14 years of 
age.  Four doses (1, 3, 6, and 9 mg) were evaluated sequentially.  Each dose was studied in a 
cohort of 6 or 10 subjects, where all subjects received nusinersen.study treatment.  In this study, 
all subjects completed dosing and follow-up visits per protocol.  Overall, ISIS 396443 was well 
tolerated, and no safety concerns were identified up to the 9-mg dose given as a single IT 
injection.  No serious adverse events (SAEs) or dose-limiting toxicities were reported in ISIS 
396443-CS1.  Adverse events (AEs) were mild or moderate in severity, and there was no 
relationship with ISIS 396443 dose.  In addition, no ISIS 396443-related adverse changes in 
neurological examinations were reported despite intensive monitoring during the immediate 
postdosing period.  CSF and plasma drug concentrations observed were generally consistent with 
predictions made from nonclinical monkey studies.
NusinersenISIS 396443 was evaluated in 3 additional completed studies, ISIS 396443-CS2, 
ISIS 396443-CS3B, and ISIS 396443-CS10, and ISIS 396443 is also currently being 
evaluated in 5 4 additional ongoing studies:  ISIS 396443 -CS2, ISIS 396443-CS10, 
ISIS 396443-CS12, and ISIS 396443-CS3A, ISIS 396443-CS4, ISIS 396443-CS11, and 
232SM202. 
Study ISIS 396443-CS2 (completed) was is an open-label, multiple-ascending-dose Phase 1/2a 
study designed to assess the safety, tolerability, and PK of nusinersenISIS 396443 in subjects 
with SMA.  Multiple doses of nusinersenISIS 396443, ranging from 3 to 12 mg, wereare being 
administered by IT injection to 2- to 15-year-old subjects with SMA 2 to 15 years of age.  
Study ISIS 396443-CS3B (completed) was a randomized, double-blind, sham-procedure 
controlled study designed to assess the clinical efficacy, safety, and PK of nusinersen in 
subjects with infantile-onset SMA.  A 12-mg dose equivalent scaled by CSF volume was 
evaluated in infants with symptomatic SMA ≤7 months of age at Screening. 
Study ISIS 396443-CS10 (completed) wasis an open-label, single-dose, redosing study of 
subjects with SMA who previously participated in Cohorts 2, 3, and 4 in Study ISIS 396443-
CS1.  
Study ISIS 396443-CS12 is an ongoing open-label study to assess the safety and tolerability of a 
single IT dose of nusinersenISIS 396443 (12 mg) in subjects with SMA who previously 
participated in either Study ISIS 396443-CS2 or Study ISIS 396443-CS10. 
Study ISIS 396443-CS3A is an ongoing, open-label, multiple-dose study designed to assess the 
safety, tolerability, and PK of nusinersenISIS 396443 in subjects with infantile-onset SMA.  
Multiple doses of nusinersenISIS 396443 are being administered by IT injection to symptomatic 
infants with SMA ≤7 months of age.  Two doses (6- and 12-mg dose equivalent scaled by CSF 
volume) are being evaluated sequentially.
Study ISIS 396443-CS4 is an ongoing, randomized, double-blind, sham-procedure 
controlled study designed to assess the clinical efficacy, safety, and PK of nusinersen in 
subjects with later-onset SMA 2 to 12 years of age at Screening.  

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Study ISIS 396443-CS11 is an ongoing, open-label, extension study being conducted to 
evaluate the long-term safety, tolerability, and efficacy of nusinersen administered IT to 
subjects with SMA who previously participated in investigational studies of nusinersen.
Study 232SM202 is an ongoing, randomized, double-blind, sham-procedure controlled 
study to assess the safety and tolerability and to explore the efficacy of nusinersen 
administered by IT injection in subjects with SMA who are not eligible to participate in the 
Studies ISIS 396443-CS3B or ISIS 396443-CS4.
The primary support for the safety and efficacy of nusinersen in the treatment of SMA is 
derived from the final analysis of Study ISIS 396443-CS3B, the sham-controlled study in 
subjects with infantile-onset SMA, and the pre-planned interim analysis of Study 
ISIS 396443-CS4, the sham-controlled study in subjects with later-onset SMA.  Subjects 
receiving nusinersen achieved statistically significant improvements in motor function 
compared with subjects in the control arms.
Nusinersen has a favorable safety profile.  In Study ISIS 396443-CS4, there was a greater 
change from Baseline in Hammersmith Functional Motor Scale – Expanded (HFMSE) 
score at 15 months for subjects with later-onset SMA who received nusinersen relative to 
subjects in the control group.  In Study ISIS 396443-CS3B, there was greater improvement 
in motor milestones, as assessed by Section 2 of the Hammersmith Infant Neurological 
Examination (HINE), for subjects with symptomatic infantile-onset SMA who received 
nusinersen relative to subjects in the control group.
Uncontrolled studies involving subjects with infantile-onset SMA (Study ISIS 396443-
CS3A) and later-onset SMA (longitudinal analyses of Studies ISIS 396443-CS2 and 
ISIS 396443-CS12) are highly supportive of the results of the pivotal efficacy studies 
(Studies ISIS 396443-CS3B and ISIS 396443-CS4) and provide evidence of the long-term 
benefit of treatment with nusinersen.
See the Investigator’s Brochure for detailed information on clinical studies.  
Rationale:  This section was updated to reflect the most recent information regarding completed 
and ongoing studies of nusinersen in subjects with SMA.
This change also affects Section 4.5, Rationale for Dose and Schedule Selection.
Section 4.5, Rationale for Dose and Schedule Selection
Change:  The dosing language was updated to reflect a fixed dose (12 mg [5 mL]) of nusinersen; 
additional support for maintenance dose was also included.

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Now reads:  
The nusinersenISIS 396443 dose and dose interval for this study were selected based on 
nonclinical toxicology and PK observations from monkey studies in monkeys using single-dose 
and repeat-dosing IT administration, consideration of the target tissue concentration anticipated 
for drug pharmacology, and safety data in the completed and ongoing clinical studies of 
nusinersenISIS 396443 to date.  Based on the pharmacology and PK results in SMA transgenic 
mice, it wasis estimated that a target spinal cord tissue concentration between 21 and 10 μg/g 
will produce 50% to 90% SMN2 exon 7 inclusion.  Nonclinical studies in juvenile monkeys 
receiving IT doses of nusinersenISIS 396443 showed a resulting gradient of distribution of 
nusinersenISIS 396443 along the spinal cord, with mean lumbar spinal cord concentrations 
ranging from 1.6- to 2.3-fold and 2.0- to 3.5-fold higher than thoracic and cervical spinal cord 
levels, respectively.  The dose selected for this multiple-dose clinical study (equivalent to 12 mg 
of nusinersenISIS 396443) is predicted to achieve levels at the high end of this range 
(approximately 10 μg/g lumbar and 3 μg/g cervical spinal cord tissue concentrations) after the 
first dose.  The loading dose interval (i.e., doses on Days 1, 15, 29, and 64) was selected based 
on the nonclinical PK and pharmacology data in order to achieve and maintain ISIS 396443 
spinal cord tissue levels that are predicted to be above or within the upper end of the 
pharmacologically active range by Day 64 (approximately 30 μg/g lumbar and 10 μg/g cervical 
tissue concentration), while at the same time considering subject safety and convenience for 
repeated IT injections by lumbar puncture (LP).  The maintenance dose interval (once every 
4 months or 119 days) was selected based on the estimated spinal tissue and CSF drug half-life 
(4 to 6 months) and was selected to maintain spinal cord tissue levels of ISIS 396443 at a 
steady-state level within the estimated pharmacologically active range.  Maintenance doses will 
be given on Days 183, 302, 421, 540, 659, and 778, for a total of 10 doses over the study period.
The loading dose interval (i.e., doses on Days 1, 15, 29, and 64) was selected as the dose 
interval based on the nonclinical PK and pharmacology data to achieve and maintain 
nusinersen spinal cord tissue levels that are predicted to be within the upper end of the 
pharmacologically active range by Day 64 (predicted to be approximately 30 μg/g lumbar 
and 10 μg/g cervical tissue concentrations), while at the same time considering subject 
safety and convenience for repeated lumbar puncture (LP) IT injections.  
The maintenance dose interval (once every 4 months or 119 days) was selected based on 
nonclinical PK and pharmacology data and clinical PK data from subjects in ongoing and 
completed clinical studies, with the goal of maintaining the spinal cord tissue levels of 
nusinersen at a steady-state level within the estimated pharmacologically active range.  The 
elimination half-life of nusinersen from human CSF is approximately 135 to 177 days and 
was estimated based on a limited number of postdose levels. Although CNS tissue half-life 
cannot be measured in humans, the median terminal elimination half-life was measured in 
the CNS tissue of adult monkeys and was found to be 116 days (approximately 
4 months). Because the site of action of nusinersen is within the CNS tissues, these findings 
support maintenance doses administered every 4 months.

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Nusinersen will be administered as an IT injection.  All subjects will be dosed with 12 mg 
(5 mL) regardless of age.  Because results from PK models showed similar concentrations 
and potential for higher efficacy with higher concentrations, the dosing regimen was 
adjusted to 12 mg (5 mL) regardless of age, which in result will lower the risk for dosing 
errors while still maintaining favorable safety margins.  Dosing instructions and details 
regarding administration will be provided in the Directions for Handling and 
Administration (DHA).  In previous versions of the protocol (Versions 1 through 5), the 
volume of the injection, and thus the dose, was adjusted based on the subject’s age on the 
day of dosing, such that each subject received a 12-mg scaled equivalent dose based on CSF 
volume scaling.  Thus, younger subjects were given a lower dose of nusinersen, achieved by 
injecting a smaller volume that was proportional to the estimated CSF volume for age, such 
that the dose volume was equivalent to 5 mL for a 2-year-old child to adult.  ISIS 396443 
will be administered as an IT injection.  The volume of the injection, and thus the dose, will be 
adjusted based on the subject’s age on the day of dosing, such that each subject will receive a 12-
mg scaled equivalent dose based on CSF volume scaling.  Thus, younger subjects will be given a 
lower dose of drug, achieved by injecting a smaller volume that is proportional to the estimated 
CSF volume for age, such that the dose volume will be equivalent to 5 mL for a 2-year-old child 
to adult.
Rationale:  The update to a fixed dose (12 mg [5 mL]) of nusinersen is strongly supported by 
results from PK models, which showed similar concentrations and potential for higher efficacy 
with higher concentrations. 
The population PK model (using n = 100 per age group) suggests that there is a similar area 
under the concentration-time curve (AUC) from zero to infinity across all age groups, but a 
higher maximum observed concentration (Cmax) in the youngest age group (i.e., <3 months), with 
the fixed dose (relative to the age-adjusted dose; Figure 1 and Figure 2).  There was high 
variation in the prediction of Cmax as a result of only trough cerebrospinal fluid (CSF) data being 
available for population pharmacokinetic (PK) model analysis (percent coefficient 
variation >100%) and distribution of parameters across age groups that largely overlap, 
regardless of whether fixed or age-adjusted dosing was used.  Given the fact that the AUC is 
similar regardless of fixed or age-adjusted dose and that there is substantial overlap in the range 
of estimates for each age group, neither method is likely to produce clinically relevant 
differences in exposure across different age groups.

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Figure 1:
CSF Cmax (ng/mL) Plots in Different Age Groups After Single Fixed (Top) or 
Age-Adjusted Dose (Bottom) [Semi-Logarithmic Scale]
Cmax = maximum plasma concentration; CSF = cerebrospinal fluid; GRP = group; mon = month; STDY = study; 
yr = year.

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Figure 2:
CSF AUCinf (ng × hr/mL) Plots in Different Age Groups After Single Fixed 
(Top) or Age-Adjusted Dose (Bottom) [Semi-Logarithmic Scale]
AUCinf = area under the plasma concentration-time curve from zero to infinity; CSF = cerebrospinal fluid; 
GRP = group; mon = month; STDY = study; yr = year.
This change also affects Section 5.2, Schedule of Activities:  Day 897 Through Day 1820 (End 
of Study), Section 7.1, Study Overview, and Section 11.1, Regimen.
Section 6.2.2, Secondary Endpoints
Change:  Secondary endpoints of change from Baseline in Hammersmith Functional Motor 
Scale – Expanded (HFMSE) and neurological examinations were added. 

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Now reads:  
Efficacy
The secondary efficacy endpoints of this study are as follows (all assessed at approximately 13 
and 24 months of age, unless otherwise noted):

Proportion of subjects developing clinically manifested SMA as defined by any of the 
following:
o
Age-adjusted weight <5th percentile or decrease of ≥2 major weight growth 
curve percentiles (3rd, 5th, 10th, 25th, or 50th) or a percutaneous gastric tube 
placement for nutritional support
o
Failure to achieve the ability to sit without support
o
Failure to achieve standing with assistance
o
Failure to achieve hands-and-knees crawling
o
Failure to achieve walking with assistance by 24 months of age
o
Failure to achieve standing alone by 24 months of age
o
Failure to achieve walking alone by 24 months of age

Proportion of subjects alive

Attainment of motor milestones assessed as part of the HINE (Section 2)

Attainment of motor milestones as assessed by World Health Organization (WHO) 
criteria

Change from Baseline in the Children’s Hospital of Philadelphia Infant Test of 
Neuromuscular Disorders (CHOP INTEND) motor function scale

Change from Baseline in HFMSE

Change from Baseline in growth parameters:  weight for age/length, head 
circumference, chest circumference, head to chest circumference ratio, and arm 
circumference
Safety
The secondary safety endpoints of this study are as follows:

Incidence of AEs and/or SAEs

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13.1.2
Growth Parameters
Growth parameters of body length and/or height (for all subjects), head circumference (for 
subjects up to 36 months of age), chest circumference (for subjects up to 36 months of age), 
and arm circumference (for subjects up to 36 months of age) will be measured at every 
onsite visit throughout the study. 
Additional parameters of weight-for-age, weight-for-length, and head-to-chest 
circumference ratio will be calculated.
13.1.3
Motor Milestones
The assessments that are performed at a given visit will depend on the subject’s age at that 
visit and current motor abilities.  For the purposes of this protocol, ambulatory will be 
defined as any subject who has achieved independent walking as defined by the WHO 
Motor Milestones criteria (Test Item #6 – Walking Alone).  Videotaping of the WHO 
and/or HINE motor milestone assessments will be optional.
For all subjects, motor milestones will be assessed using the WHO Motor Milestones 
criteria [WHO Multicentre Growth Reference Study Group 2006; Wijnhoven 2004].
For subjects <2 years of age who have not yet achieved independent walking, motor 
milestones will be assessed using Section 2 of the HINE, which is composed of 8 motor 
milestone categories as follows:  voluntary grasp, ability to kick in supine position, head 
control, rolling, sitting, crawling, standing, and walking.  Within each motor milestone 
category, there are 3 to 5 levels that can be achieved.  All 8 motor milestones will be tested 
during each assessment.  A subject whose results after testing all appear in the first column 
(no grasp, no kicking, unable to maintain head upright, and so on) has not achieved any 
motor milestone.  Motor milestone achievement is depicted by movement from the left side
of Table 4 to the right side of the table, as denoted by the Milestone Level Progression 
arrow in the table [Haataja 1999].

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Table 4:
Hammersmith Infant Neurological Examination Section 2 - Motor 
Milestones
Motor 
Milestone 
Category
Milestone Level Progression
(Age Expected in Heathy Infants1)
Voluntary 
grasp
No grasp
Uses whole 
hand
Finger and 
thumb; 
immature grasp
Pincer grasp
Ability to 
kick (in 
supine)
No kicking
Kicks 
horizontal; 
legs do not lift
Upward 
(vertically) 
[3 months]
Touches leg 
(4 to 
5 months)
Touches toes 
(5 to 
6 months)
Head control
Unable to 
maintain 
upright 
(<3 months)
Wobbles 
(4 months)
All the time 
upright 
(5 months)
Rolling
No rolling
Rolling to side 
(4 months)
Prone to supine 
(6 months)
Supine to 
prone 
(7 months)
Sitting
Cannot sit
Sit with 
support at 
hips 
(4 months)
Props
(6 months)
Stable sit 
(7 months)
Pivots 
(rotates) 
[10 months]
Crawling
Does not lift 
head
On elbow 
(3 months)
On outstretched 
hand (4 to 
5 months)
Crawling flat 
on abdomen 
(8 months)
On hands 
and knees 
(10 months)
Standing
Does not 
support weight
Supports 
weight (4 to 
5 months)
Stands with 
support 
(8 months)
Stands 
unaided 
(12 months)
Walking
No walking
Bouncing 
(6 months)
Cruising 
(holding on) 
[11 months]
Walking 
independently 
(15 months)
1 Values for healthy infants in [Haataja 1999].
The proportion of motor milestone responders is defined based on the 8 motor milestones 
categories, with the exclusion of voluntary grasp using the assessment at the later study 
visits, as follows: 
i.
Subject demonstrates at least a 2-point increase in the motor milestone category 
of ability to kick or achievement of the maximal score on that category (touching 
toes) or a 1-point increase in the motor milestones of head control, rolling, 
sitting, crawling, standing, or walking; AND 

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ii.
Among the 8 motor milestone categories with the exclusion of voluntary grasp, 
subject demonstrates improvement (defined in [i]) in more categories than 
worsening.  Note:  For the category of ability to kick, similar to the definition of 
improvement in (i) mentioned previously, worsening is defined as at least a 2-
point decrease or decrease to the lowest possible score of no kicking.  For the 
other 6 categories, worsening is defined as at least a 1-point decrease. 
13.1.4
Motor Function Assessments
Motor function assessments include all assessments listed in Section 13.1.4.1, 
Section 13.1.4.2, and Section 13.1.4.3.  The assessments that are performed at a given visit 
will depend on the subject’s age at that visit and current motor abilities.
Videotaping of all motor function assessments will be optional.
13.1.4.1
Children’s Hospital of Philadelphia Infant Test for Neuromuscular Disease
CHOP INTEND will be assessed in subjects with infantile-onset SMA until they have a 
maximum score of 64.  Once a score of 64 is achieved, CHOP INTEND will no longer be 
assessed.
The CHOP INTEND test was specifically designed to evaluate the motor skills of infants 
with significant motor weakness, including infants with SMA [Glanzman 2010].  The 
CHOP INTEND test captures neck, trunk, and proximal and distal limb strength in 
14 elicited and 2 observational items.  The CHOP INTEND has been established as a safe 
and reliable infant motor measure in infantile-onset SMA and has been validated 
[Glanzman 2011].  
13.1.4.2
Hammersmith Functional Motor Scale - Expanded
All subjects ≥2 years of age will be evaluated using the HFMSE for the duration of the 
study.  Subjects who are ≥2 years of age but have not yet achieved the maximum score of 
64 with CHOP INTEND will be assessed with both until a CHOP INTEND maximum score 
of 64 is achieved.  The HFMSE should be performed after the CHOP INTEND with an 
approximately 15-minute rest period in between to allow the subject to be fully engaged 
with both assessments.
The HFMSE is a reliable and validated tool used to assess motor function in children with 
SMA.  The scale was originally developed with 20 scored activities and was devised for use 
in children with Type II and Type III SMA with limited ambulation to give objective 
information on motor ability and clinical progression [Main 2003].  The expanded scale 
includes an additional module of 13 items developed to allow for evaluation of ambulatory 
patients with SMA [O'Hagen 2007].  The HFMSE has been shown to be highly correlated 
with other clinical assessments and has shown good test-retest reliability. 

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14.1.1
Neurological Examinations
Neurological examinations will be performed predose and approximately 3 and 6 hours 
after dosing from Day 1 through Day 779 and predose and approximately 1 hour after 
dosing from Day 897 through Day 1820.  Please note:  If sedation was used, please allow 
sufficient recovery time for the subject to be fully engaged in the examination.  It is 
important that the data collected truly reflect the subject’s neurological performance.
The HINE (Sections 1 and 3) will be conducted in all subjects ≤24 months of age.  This 
standard examination (developed by [Dubowitz and Dubowitz 1981]) is a quantitative 
scorable method for assessing the neurological development of infants between 2 and 24 
months of age.  The examination includes assessment of cranial nerve functions, posture, 
movements, tone, and reflexes.
For all subjects >24 months of age, standard neurological examinations, which include 
assessments of mental status, level of consciousness, sensory function, motor function, 
cranial nerve function, and reflexes, will be conducted.
14.1.2
Electrocardiograms
ECGs will be performed for all subjects at Screening, Day 2, Day 29 postdose, Day 365, 
Day 700, Day 897, Day 1254, Day 1611, Day 1820, and at the Early Termination Visit.  
After the ECG is completed, an initial local read of the ECG should occur before the ECG 
is sent for central read (all ECGs will be centrally read).  If the subject’s initial ECG results 
show a QTc interval of ≥500 ms, then the ECG should be repeated (prior to the subject 
leaving the visit).  If the second ECG QTc again reads ≥500 ms, the physician should use 
his or her best clinical judgement to address the condition.
Additional ECGs may be performed per the judgement of the Investigator, as deemed 
clinically necessary.
14.1.3.
Physical Examinations
Physical examinations will be performed for all subjects at every onsite visit throughout the 
study.  Any abnormal findings observed during physical examinations will be captured as 
AEs and reported according to Section 15.
Videotaping of the physical examinations will be optional.
14.1.4.
Vital Signs
Vital signs include systolic and diastolic blood pressure, pulse rate, respiratory rate, and 
temperature.  Additionally, pulse oximetry will be collected.  From Screening through Day 
779, vital signs and pulse oximetry will be collected predose and at 4 timepoints postdose:  
1, 2, 4, and 6 hours.  From Day 897 through Day 1820, vital signs and pulse oximetry will 

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be taken predose and approximately 1 hour postdose at every onsite visit throughout the 
study.
Rationale:  This language was added to thoroughly monitor the neurologic condition, ECG 
readings, physical condition, and vital signs of subjects with presymptomatic SMA who received 
nusinersen.
This change also affects Section 5, Schedule of Activities for Study 232SM201.
Section 14.2, Laboratory Safety Assessments
Change:  The section was revised to detail when laboratory safety assessments will be 
performed, and the specific analytes were detailed in Appendix A.  Language regarding 
coagulation testing was added.  Additional hematology, serum chemistry, and coagulation testing 
visits were added to the schedule.
Now reads:  
The following laboratory tests will be performed to evaluate the safety profile of ISIS 396443:

Hematology:  red blood cells, hemoglobin, hematocrit, platelets, white blood cells, 
white blood cell differential

Blood chemistry:  total protein, albumin, creatinine, creatine phosphokinase, blood 
urea nitrogen, total bilirubin (direct and indirect), alkaline phosphatase, alanine 
aminotransferase, aspartate aminotransferase, glucose, calcium, phosphorus, chloride, 
sodium, potassium

Urinalysis:  specific gravity, pH, protein, glucose, ketones, bilirubin, red blood cells, 
white blood cells, epithelial cells, bacteria, casts, crystals

Cystatin C (for subjects with Screening weight of ≥3 kg)
Coagulation (performed at local labs):  aPTT, PT, INR
Laboratory measurements of serum chemistry, hematology, urinalysis, and urine total 
protein will be collected at Screening, Day 15, Day 29, and every 4 months thereafter (i.e., 
Days 64, 183, 302, 421, 540, 659, 778, 897, 1016, 1135, 1254, 1373, 1492, 1611, and 1730), as 
well as on Day 365, Day 700, and Day 1820 (End of Study)/Early Termination Visit.  The 
laboratory analytes to be measured are shown in Appendix A.  For urinary protein 
concentration >0.2 g/L, repeat testing and further evaluation should be considered.
Due to blood collection volume limitations for newborns, the laboratory safety assessments 
described above will be performed according to the schedules listed in Table 75 and Table 86.  

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Coagulation testing will be conducted at each visit at the time of the implementation of this 
amendment (Protocol Version 6), and results must be reviewed prior to dosing.  
Coagulation testing was not performed at every visit in previous versions of the protocol 
(Versions 1 through 5); therefore, not all subjects will have coagulation results prior to all 
doses.
Table 75:
Laboratory Safety Blood Collection Schedule for Subjects with a Screening 
Weight of ≥3 kg
Panel/Test
Screening1
Day 
1
Day 
15
Day 
29
Day 
64
DaysDay183, 
302, 421, 540, 
659, 778 D183, 
D302, D421, 
D540, D659, 
D778 (±7D)
Days 365, 700, 897, 1016, 
1135, 1254, 1373, 1492, 
1611, 1730, 1820 D365, 
D700, D868 (±7D), and 
Early Term
Hematology
X
X
X
X
X
X
Serum 
Chemistry
X
X
X
X
X
X
Cystatin C
X
X2
X2
X
Coagulation
X3
X
X
X
X
X
X
D = day(s); Term = termination.
1 Screening laboratory tests will be collected over a two or more day period.
2 At Day 183 or when the subject’s weight is ≥5.4 kg, whichever comes first, the blood collection schedule will 
revert to that outlined in Section 5.
3 Coagulation testing must be reviewed prior to dosing on Day 1.
Table 86:
Safety Labs Blood Collection Schedule for Subjects with a Screening Weight of 
<3 kg
Panel/Test
Screening1
Day 
1
Day 
15
Day 
29
Day 64
DaysDay
183, 302, 
421, 540, 
659, 778
D183, 
D302, 
D421, 
D540, 
D659, D778
(±7D)
Days 365, 700, 897, 
1016, 1135, 1254, 
1373, 1492, 1611, 
1730, 1820 D365, 
D700, D868 (±7D), 
and Early Term
Hematology
X
X
X
X
X
X
Serum 
Chemistry
X
X
X
X
X
X
Coagulation
X
X2
X
X
X
X
X
D = day(s); Term = termination.
1 Screening laboratory tests will be collected over a two or more day period. 

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2 Coagulation testing must be performed and reviewed prior to dosing on Day 1.
Rationale:  These assessments were added to thoroughly evaluate coagulation parameters in 
subjects with presymptomatic SMA who received nusinersen.
This change also affects Section 5, Schedule of Activities for Study 232SM201 and led to the 
creation of Appendix A, Laboratory Analytes.
Section 15.1.1, Adverse Event
Change:  The definition of adverse events was revised.
Now Reads:
An AE is any untoward medical occurrence in a patient or clinical investigation subject 
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 ana 
clinically significant abnormal laboratory finding, for example), 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, vital sign result, and/or ECG result 
meets the definition of an AE will be made by the Investigator.  Abnormal resultslaboratory 
findings that are considered by the Investigator as not consideredclinically significant should not 
be reported as AEs unless 1 or more of.  Although abnormal laboratory values are typically not 
considered AEs, the following criteria are metconsiderations may result in an abnormal 
laboratory value being considered an AE:

TheA laboratory test result that meets the criteria for an SAE

TheA laboratory test result that requires the subject to receive specific corrective 
therapy

The result is considered byA laboratory abnormality that the Investigator considers
to be clinically significant
Rationale:  The language was updated to be consistent with the current protocol template for 
Biogen-sponsored studies.
Section 15.4.1, Overdose
Change:  The section was expanded to define the conditions when a dosing error will be 
considered an overdose.

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Now reads:  
An overdose is any dose of study treatment given to a subject or taken by a subject that exceeds 
the dose described in the protocol, and must be documented as a protocol deviation.  All dosing 
errors (including but not limited to route of administration, wrong dose, etc.) must be 
reported as protocol deviations.  A brief description should be provided in the deviation, 
including whether the subject was symptomatic or not (with a list of symptoms) or 
asymptomatic.  Dosing details should be captured on the Dosing CRF.
A dosing error will be considered an overdose when any of the following conditions are 
met:

A dose given exceeds the dose level described in the protocol and Drug Handling 
Guidelines

Dosing frequency exceeds 4 doses in a 2-month period (and, thus, results in a 
higher than acceptable cumulative dose)

Any time study treatment is administered less than 2 weeks from the previous 
dose
Overdoses are not considered AEs and should not be recorded as an AE on the CRF unless an 
AE or an SAE occurs.  ; however, allAll overdoses (regardless of whether or not they result 
in an AE) must be recorded on an overdose form and faxed must be reported to the Medical 
Monitor to the Sponsor (or designee) within 24 hours of the site becoming aware of the 
overdose.  An overdose must be reported to the Medical Monitor even if the overdose does not 
result in an AE.  If an overdose results in an AE, then the AE must be recorded.  If an overdose 
results in an SAE, then both the SAE form and overdose forms must be completed and faxed to 
the Sponsor (or designee).  Should an overdose occurs, the Investigator or designee must 
contact the Medical Monitor within 24 hours; refer to the Study Reference Guide for the 
complete contact SynteractHCR Safety.  All study treatment-related dosing information must be 
recorded on the dosing CRF.
Rationale:  This text was added to address this potential event and to collect information on 
overdoses.
Section 16, Statistical Methods and Determination of Sample Size
Change:  The definition of study baselines were revised.

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Now Reads:
In general, continuous variables will be summarized by descriptive statistics, including number, 
mean, median, standard deviation, minimum, and maximum.  Categorical variables will be 
presented with the number and percentage in each category. 
The Full Analysis Set (FAS) is defined as all subjects who receive at least 1 dose of 
nusinersenISIS 396443.
The Per-Protocol Set (PPS) will include the subset of the FAS who complete at least the initial 
4 doses of study treatmentdrug, have a baseline and at least the Day 183 efficacy assessments, 
and who have no significant protocol deviations that would be expected to affect efficacy 
assessments.
Baseline will be defined as the closest available assessment on or prior to Day 1 Predose.
A number of the endpoints are age specific and, therefore, over the course of the study as 
subjects get older, different scales will be utilized.  Three baselines will be defined.  The 
first baseline will be defined as the closest available assessment on or prior to Day 1 
predose when the child is <6 weeks of age.  The second baseline will be defined as on or 
prior to the Day 700 visit when the child is approximately 2 years of age.  The third 
baseline will be defined as on or prior to Day 897 predose visit when the child is 
approximately 2.5 years of age.
The objectives of the study and the endpoints to be analyzed are listed in Section 6.
Rationale:  The language was added to clarify that different baselines will be utilized, which 
will be further defined in the Statistical Analysis Plan.
Section 16.1, Efficacy
Change:  The section was updated to include analysis plan for additional assessments.
Now Reads:
16.1.1.
Analysis Population
The primary analysis of efficacy will be performed on subjects in the FAS with 2 SMN2 copies.  
Analyses will be repeated in the FAS and PPS, as well as in the PPS with 2 SMN2 copies.  For 
the longitudinal analyses of certain endpoints, it may be necessary to define additional 
efficacy sets.

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16.1.2.2.
Analysis of the Secondary Endpoints
ForAge:  <6 weeks to 2 years
During this period, the purposes of analysis, the secondary endpoints are classified into the 
following:

Achievement of milestones at approximately 13- and 24 months of age

Other
Achievement of Milestones
-Month Visit is of most interest.  The visit at Day 365 will be used for the assessment of the 
endpoint at 13 month milestone months and the visit at Day 700 will be used for the assessment 
of the 24 month milestone endpoint at 24 months.  The proportion of subjects meeting the 
criteria for the following at the 13- and 24-Month Visit will be presented with a corresponding 
95% CI:

Clinically manifested SMA defined by any one of the following:
o
If at the 13- or 24-Month Visit, the subject’s weight has dropped below the 5th 
percentile according to WHO criteria [WHO 2014][WHO 2014]; or if compared 
to Baseline, a subject has decreased ≥2 major weight growth curve percentiles 
(3rd, 5th, 10th, 25th, or 50th) according to WHO criteria; or if a percutaneous 
gastric tube has been required at any point up to and including the 13- or 24-
Month Visit, as documented in the concomitant procedures in the CRF
o
Failure to demonstrate the following as assessed by the WHO motor milestones: 

At 13 and 24 months of age:  ability to sit without support, standing with 
assistance, hands and knees crawling

Additionally at 24 months of age:  walking with assistance, standing 
alone, and/or walking alone 
o
Subjects who discontinue or die on or before the 13- or 24-Month Visit

Achievement of each individual motor milestone as assessed by the HINE (Section 2) 
and the WHO motor milestones.  Subjects who discontinue prior to the 13- or 24-Month 
Visit will be counted in the denominator.

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Now Reads:
Safety data will be reviewed on an ongoing basis by the Sponsor and the Medical Monitor.  
Safety data will also be reviewed on an ongoing basis by an independent Data and Safety 
Monitoring Board (DSMB).  The Sponsor and Medical MonitorDSMB will be assembled to
review safety, tolerability, and efficacy (as needed) data collected on nusinersenISIS 396443 
during this study.  Based on its ongoing assessment of the safety and tolerability of ISIS 396443, 
the DSMB will provide recommendations to the Sponsor for modifying, stopping, or continuing 
the study as planned.
Rationale:  Given the established safety profile, the DSMB will no longer be assembled.  Going 
forward, ongoing safety review will be conducted by the Sponsor and Medical Monitor.

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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.

The Ionis logo was replaced with the Biogen logo on the title page.

The Sponsor Signatory information was updated, and a signature page was added.

The List of Abbreviations was updated.

When referring to “study treatment,” “nusinersen” is used in place of “ISIS 396443”.  
When referring to the protocol title or previous (“index”) studies, ISIS 396443 is 
used.  The term “study treatment” refers to administration of nusinersen or the sham 
procedure during the blinded portion of the study.

The phrase “Study Reference Manual” was replaced with “Study Reference Guide”.

Section 7.2.2, Treatment, was updated to specify that an overnight stay is required for 
the first injection but is otherwise optional.

Section 10.1, Discontinuation of Study Treatment, was updated to detail that the 
primary reason for discontinuation of study treatment must be recorded.

Section 10.2, Withdrawal of Subjects From Study, was updated to detail that subjects 
who withdraw from the study will not be replaced.

Section 11.5.2, Concomitant/Ancillary Procedures, was updated to include the word 
“ancillary.”

Section 12, Study Treatment Management, was updated to include a sentence 
describing the manufacture, handling, and storage of study treatment in accordance 
with applicable Good Manufacturing Practice.

Section 12.1, Nusinersen, was revised to remove a sentence stating that ISIS396443 is 
manufactured by Isis Pharmaceuticals Inc.

Section 12.1.2, Nusinersen Storage, was revised to include information regarding the 
Directions for Handling and Administration.

Section 12.1.3, Nusinersen Handling and Disposal, was updated to include guidance 
for onsite destruction.

Section 12.1.4, Nusinersen Accountability, was updated to include language 
regarding the loss of nusinersen.

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
Section 15.1.2, Serious Adverse Events, was updated to be consistent with the current 
protocol template for Biogen-sponsored studies.

Section 15.3.1, Adverse Events, and Section 15.5.1, Investigator, were updated to 
state that the Investigator will assess the subject at every visit and record new adverse 
events (AEs) or updates to previously reported AEs on the case report form (CRF).

Section 15.3.2, Serious Adverse Events; Section 15.3.3, Immediate Reporting of 
Serious Adverse Events; Section 15.3.3.1, Deaths; Section 15.4.1, Overdose; and 
Section 15.5.1, The Investigator; were revised to clarify that serious AEs, deaths, and 
overdose should be reported to the safety vendor listed in the Study Reference Guide 
and not to SynteractHCR Safety.

Section 15.5, Safety Responsibilities, was revised to add that AE follow-up 
information and resolution should be recorded on the CRF by the Investigator.

Section 17, Ethical Requirements; Section 17.1, Declaration of Helsinki; 
Section 17.3, Subject Information and Consent; and Section 17.4, Subject Data 
Protection; were updated to be consistent with the current protocol template for 
Biogen-sponsored studies.

Section 18, Administrative Procedures, was expanded to add information regarding 
quality assurance and monitoring of the study.

Section 20, References, was revised to reflect the changes in references cites 
throughout the protocol. 

Typographical and formatting errors were corrected.

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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 232SM201 
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy 
Version 5 
Date:  15 December 2015 
EUDRA CT Number:  2014-002098-12 
Version 5 of the protocol has been prepared for this amendment, which supersedes Version 4. 
 

Protocol 232SM201, Version 5 
 
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Biogen MA Inc. 
2 
PRIMARY REASON FOR AMENDMENT 
The primary reason for this amendment to Protocol 232SM201 is to allow formal data reviews 
and interim analysis(es) to be performed during the course of the study. 
New text is shown in bold type; deleted text is shown with a strikethrough. 
 
Section 16.7, Interim Analysis 
Now reads: 
Interim data analyses may be performed after approximately 10 subjects have been 
enrolled.  Further details about these analyses will be described in the Statistical Analysis 
Plan.  No formal interim analyses will be conducted.  
 
Rationale:  The purpose of the interim analysis(es) is to provide study sponsors and regulators 
with information on the status of this ongoing study. 
 

Protocol 232SM201, Version 5 
 
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3 
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. 

Protocol 232SM201, Version 5 
 
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Biogen MA Inc. 
4 
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. 
 The Biogen Therapeutic Area was updated. 
 The primary and secondary contacts for urgent medical issues were updated.  

CONFIDENTIAL
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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 232SM201
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy
Version 4
Date:  30 September 2015
EUDRA CT Number:  2014-002098-12
Version 4 of the protocol has been prepared for this amendment, which supersedes Version 3 
dated 18 December 2014.

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3
Now reads:
Table 1:
Schedule of Activities
Note: Monitoring telephone calls will occur on a monthly (± 7 days) basis starting on Day 94 and continuing to the end of the study.1
Study Period
Screen
21
Treatment/Follow-Up
Study Day
D -21
to
D -1
D1
D2
D15 (±1D)
D1
6
D29 (±1D)
D3
0
D64, D183, D302, 
D421, D540, D659, 
D778 (±7D)
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7793
2
D365, 
D700,
D868
(±7D) 
and 
Early 
Term
Pre-
Dose
L
P
Post
-
Dose
Pre-
Dos
e
LP
Post-
Dose
Pre
-
Dos
e
LP
Post
-
Dose
Pre-
Dose
LP
Post-
Dose
Informed Consent
X
Inclusion/Exclusion Criteria
X
X43
Medical History
X
Sibling SMA Data4
X
X
Vital Signs & Pulse Oximetry5
X
X
4X6
X7
X
4X6
X
X
4X6
X
X
4X6
X
X
Weight
X
X
X
X
X
X
X
X
X
X
Growth Parameters8
X
X9
X
Physical Examination
X
X
X
X
X
X
Ventilator Use
X
X
X
X
X
X
X
X
X
X
Neurological Examination10
X
X
2X11
X7
X
2X11
X
X
2X11
X
X
2X11
X
X
ECG
X
X
X
X
Safety Laboratory Tests12
X
X
X9
X
Coagulation Labs
X13
Immunogenicity
X
X9
X

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4
Study Period
Screen
21
Treatment/Follow-Up
Study Day
D -21
to
D -1
D1
D2
D15 (±1D)
D1
6
D29 (±1D)
D3
0
D64, D183, D302, 
D421, D540, D659, 
D778 (±7D)
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7793
2
D365, 
D700,
D868
(±7D) 
and 
Early 
Term
Pre-
Dose
L
P
Post
-
Dose
Pre-
Dos
e
LP
Post-
Dose
Pre
-
Dos
e
LP
Post
-
Dose
Pre-
Dose
LP
Post-
Dose
CSF PK
X
X
X
X
Plasma PK14
X
X9
Study Treatment Injection1618
X
X1719
X1719
X171
9
In-Patient Stay (24 hours)1719
X
CHOP INTEND20
X1821
X9
X
HINE Motor Milestones
X1821
X9
X
WHO Motor Milestones22
X21
X9
X
Con Med Recording
X2025-----------------------------------------------------------------------------------------------------------------------------------------------------------X
Adverse Event Collection
X2126----------------------------------------------------------------------------------------------------------------------------------------------------------- X
AE = adverse event; CHOP INTEND = Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders; 
 
Con Med = concomitant medication; CSF = cerebrospinal fluid; D = day; DNA = deoxyribonucleic acid; ECG = electrocardiogram; HINE = Hammersmith 
Infant Neurological Exam; ICF = informed consent form; LP = lumbar puncture; PK = pharmacokinetic(s); RNA = ribonucleic acid; SAE = serious adverse 
event; SMA = spinal muscular atrophy; 
 Term = termination; WHO = World Health 
Organization.
1 Note: Monitoring telephone calls will occur on a monthly (± 7 days) basis starting on Day 94 and continuing to the end of the study.  At telephone contact, 
changes in concomitant medications and AEs will be recorded, as well as information on the subject’s ventilator use and SMA disease status.
21A blood sample will be collected at Screening for SMN2 copy number analysis only from those subjects without genetic documentation of SMN2 copy number.  
For all other subjects, a blood sample will be collected at any time during the study for analysis of SMN2 copy number by the central laboratory.

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Biogen MA Inc.
6
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 4, Schedule of Events for Study 232SM201
Change:  The Schedule of Activities (SoA) was updated to include sibling SMA data collection 
at Screening and Day 868/Early Termination (see Table 1 for addition to SoA and the following 
footnote).
Now reads:  If a subject has or had a sibling with SMA and if consent is given, data for the 
sibling will be collected at Screening (or the next visit after the implementation of this 
amendment) and at the Day 868 (or Early Termination) visit.  Data to be collected will be 
nonbiologic and non-invasive and will include historical data for SMN2 gene copy number, 
sibling treatment history, etc.
Rationale:  The purpose of capturing sibling SMA data (onset, progression, and treatment, if 
applicable), is to better understand SMA and its similarities or differences within and across 
families.  Sibling data will be used as a natural comparison for the progression of the disease.
Section 4, Schedule of Events for Study 232SM201
Change:  A footnote was added to the SoA to indicate that optional videotaping during the 
Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND)
test will be conducted (see Table 1 for the footnote).
Now reads:  Videotaping during the CHOP INTEND test will be optional.
Rationale:  The purpose of videotaping the subject during the CHOP INTEND test is to further 
examine the effect of the study drug on the subject and to assess the consistency of the 
examination between physical therapists, visits, sites, and for ongoing physical therapist training.
Section 8.1, Inclusion Criteria
Change:  Inclusion criterion 5 was updated to provide additional clarification regarding the 
location of the compound muscle action potential (CMAP) assessment.Now reads:  Inclusion 
Criteria
5.
Ulnar CMAP ≥1 mV at Baseline.

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7
Rationale:  Ulnar CMAP was specified in the amended criterion to provide guidance for study 
sites when assessing study eligibility, as both ulnar and anterior tibialis CMAP have been
performed previously.  This text is intended to clarify that data from ulnar CMAP readings 
should be used to confirm study eligibility.
This change also affects Section 4, Schedule of Events for Study 232SM201.

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Biogen Idec MA Inc. 
1 
 
 
 
 
 
 
 
 
 
 
Biogen Idec MA Inc. 
14 Cambridge Center 
Cambridge, MA  02142, USA 
Biogen Idec Research Limited 
Innovation House 
70 Norden Road 
Maidenhead Berkshire
SL6 4AY 
United Kingdom 
______________________________________________________________________ 
AMENDMENT SUMMARY 
Biogen Idec Protocol 232SM201 
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy 
Version 3 
Date:  18 December 2014 
EUDRA CT Number:  2014-002098-12 
Version 3 of the protocol has been prepared for this amendment, which supersedes Version 2 

Protocol 232SM201, Version 3 
 
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Biogen Idec MA Inc. 
2 
PRIMARY REASON FOR AMENDMENT 
The primary reason for this amendment to Protocol 232SM201 is to accommodate the inclusion 
of twins with spinal muscular atrophy (SMA).  The main change in the protocol that has been 
made to accommodate these subjects is the addition of a specific gestational age requirement for 
twins (34 to 42 weeks) due to the lower mean gestational age for twins. 
 
New text is shown in bold type; deleted text is shown with a strikethrough. 
 
Section 8.1, Inclusion Criteria 
 
Now reads: 
8. 
Gestational age of 37 to 42 weeks for singleton births; gestational age of 34 to 42 
weeks for twins. 
 
Rationale:  Uncomplicated pregnancies of singletons deliver babies at 37 weeks or greater of 
gestational age.  However, in pregnancies with normal twins, it is recommended to deliver 
babies in some cases as early as 34 weeks.  In fact, the mean gestational age for singleton births 
is 38.7 weeks, whereas for twins, the mean gestational age is 35.3 weeks.  Therefore, this change 
allows for babies with SMA born from normal pregnancies with twins to participate in this 
study. 
 

Protocol 232SM201, Version 3 
 
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Biogen Idec MA Inc. 
3 
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, Schedule of Events for Study 232SM201 
Change:  Table 1, Schedule of Activities, was modified. 
Now reads: 

Protocol 232SM201, Version 3 
 
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4 
Table 1: 
Schedule of Activities 
Note:  Monitoring telephone calls will occur on a monthly (±7 days) basis starting on Day 94 and continuing to the end of the study.1 
 Study Period 
Screen2 
Treatment/Follow-Up 
Study Day 
D -21 
to 
D -1 
D1 
D2 
D15 (±1D) 
D16
D29 (±1D) 
D30
D64, D183, D302, 
D421, D540, D659, 
D778 (±7D) 
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7793 
D365, 
D700,
D868
(±7D) 
and 
Early 
Term
Pre-
Dose 
LP
Post-
Dose 
Pre-
Dose
LP
 
Post-
Dose 
Pre- 
Dose 
LP 
Post-
Dose 
Pre- 
Dose 
LP 
Post- 
Dose 
Informed Consent 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Inclusion/Exclusion Criteria 
X 
X4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Medical History 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Vital Signs & Pulse Oximetry5 
X 
X 
 
4X6 
X7 
X 
 
4X6 
X 
X 
 
4X6 
X 
X 
 
4X6 
X 
X 
Weight 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
Growth Parameters8 
X 
 
 
 
 
 
 
 
 
 
 
 
 
X9 
 
 
 
X 
Physical Examination 
X 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
Ventilator Use 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
 
 
X 
X 
Neurological Examination10 
X 
X 
 
2X11 
X7 
X 
 
2X11 
X 
X 
 
2X11 
X 
X 
 
2X11 
X 
X 
ECG 
X 
 
 
 
X 
 
 
 
 
 
 
X 
 
 
 
 
 
X 
Safety Laboratory Tests12 
X 
 
 
 
 
 
 
 
 
X 
 
 
 
X9 
 
 
 
X 
Coagulation Labs 
X13 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Immunogenicity 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X9 
 
 
 
X 
CSF PK
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
 
Plasma PK1314 
 
 
 
X 
X 
 
 
 
 
 
 
 
 
X9,15 
 
X15 
 
 
Study Treatment Injection16 
 
 
X 
 
 
 
X17 
 
 
 
X17 
 
 
 
X17 
 
 
 
In-Patient Stay (24 hours)17 
 
 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Protocol 232SM201, Version 3 
 
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5 
 Study Period 
Screen2 
Treatment/Follow-Up 
Study Day 
D -21 
to 
D -1 
D1 
D2 
D15 (±1D) 
D16
D29 (±1D) 
D30
D64, D183, D302, 
D421, D540, D659, 
D778 (±7D) 
D65, 
D184 
D303, 
D422, 
D541, 
D660, 
D7793 
D365, 
D700,
D868
(±7D) 
and 
Early 
Term
Pre-
Dose 
LP
Post-
Dose 
Pre-
Dose
LP
 
Post-
Dose 
Pre- 
Dose 
LP 
Post-
Dose 
Pre- 
Dose 
LP 
Post- 
Dose 
CHOP INTEND 
X18 
 
 
 
 
 
 
 
 
 
 
 
 
X9 
 
 
 
X 
HINE Motor Milestones 
X18 
 
 
 
 
 
 
 
 
 
 
 
 
X9 
 
 
 
X 
WHO Motor Milestones 
X18 
 
 
 
 
 
 
 
 
 
 
 
 
X9 
 
 
 
X 
Con Med Recording 
X20 ------------------------------------------------------------------------------------------------------------------------------------------------------------ X 
Adverse Event Collection 
X21----------------------------------------------------------------------------------------------------------------------------------------------------------- X 
 AE = adverse event; CHOP INTEND = Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders; 
 
; Con Med = concomitant medication; CSF = cerebrospinal fluid; D = day; ECG = electrocardiogram; HINE = Hammersmith Infant Neurological 
Exam; ICF = informed consent form; LP = lumbar puncture; PK = pharmacokinetic(s); SAE = serious adverse event; SMA = spinal muscular atrophy; 
 Term = termination; WHO = World Health Organization 
1 At telephone contact, changes in concomitant medications and AEs will be recorded, as well as information on the subject’s ventilator use and SMA disease 
status. 
2 A blood sample will be collected at Screening for SMN2 copy number analysis only from those subjects without genetic documentation of SMN2 copy number. 
 For all other subjects, a blood sample will be collected at any time during the study for analysis of SMN2 copy number by the central laboratory. 
3 These safety monitoring visits will occur on the day after the subject receives an injection of study treatment. 
4 Investigator to check for signs and symptoms consistent with SMA. 
5 Resting blood pressure, pulse, respiratory rate, temperature, and pulse oximetry awake.  Pulse oximetry asleep will also be assessed at Screening only. 
6 Vital signs collected at 4 timepoints:  1, 2, 4, and 6 hours after dosing.  Pulse oximetry will not be collected postdose. 
7 Conducted within 20 to 24 hours after dosing. 
8 Length, weight for age/length, head circumference, chest circumference, head to chest circumference ratio, and arm circumference. 
9 These assessments may be performed up to 7 days prior to dosing, if necessary. 
10 Neurological examinations consist of Sections 1 and 3 of the HINE. 
11 Neurological examinations conducted at 2 timepoints:  3 and 6 hours after dosing. 
12 Serum chemistry, hematology, and urinalysis panels; refer to Table 3 and 4 for a list of analytes and collection timepoints based on the subject’s weight at 
Screening.  For subjects ≥3 kg at Screening, once they reach a weight of 5.4 kg or the Day 183 visit, whichever happens first, blood samples for all 
analytes should be collected according to the above schedule.  The blood sample for Cystatin C analysis will not be collected at any timepoint for 
subjects with a Screening weight of <3 kg.  Urinalysis will be conducted according to the above schedule, independent of the subject’s weight. 

Protocol 232SM201, Version 3 
 
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6 
13 Coagulation testing will be conducted at D1 pre-dose for subjects with a Screening weight of <3 kg.  For all subjects, results must be reviewed prior to 
dosing on Day 1. 
1314 
Refer to Table 2 for the detailed PK sampling schedule. 
 
 
15 Plasma PK collected before the injection of study treatment only on Study Days 64, 183, 302, 540, 659, and 778.  Plasma PK collected 4 h (±1 h) after the 
injection of study treatment only on Study Day 64.    
16 Injections should not occur within 72 hours after an immunization. 
17 Overnight stay is required for the first injection, but is optional for all subsequent injections, at the discretion of the Investigator. 
18 The CHOP INTEND, HINE, and WHO motor milestone assessments will be conducted as part of the initial screening assessments.  If they are conducted 
within 7 days prior to dosing, they will only need to be performed once; otherwise, they will need to be repeated within 7 days prior to dosing. 
. 
20 In addition to concomitant medications, ancillary procedures will be recorded. 
21 AEs and SAEs will be collected in the case report form from the time of signing the ICF as described in Section 15.3.1 and in Section 15.3.2. 

Protocol 232SM201, Version 3 
 
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Biogen Idec MA Inc. 
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Rationale:  The pharmacokinetic (PK) sampling schedule was updated to provide lower total 
blood collection volumes for infants with lower weight and to reflect that only plasma peak 
concentrations on D1 and trough levels on and after D64 are sufficient for population PK 
analysis.  Additionally, volume for collection of each PK sample was adjusted to 0.5 mL because 
tubes are not available to accurately collect a volume of 0.35 mL.  The 0.5-mL collections still 
provide a total blood draw volume that adheres to the limits relevant to this infantile population. 
 
Section 8.1, Inclusion Criteria 
Change:  Criterion #7 was modified. 
Now reads: 
7. 
Body weight ≥>3rd percentile for age using appropriate country-specific guidelines. at 
Screening.  
Rationale:  The phrase “at Screening” was removed as all criteria must be met at Screening to 
be included in the study.  The “>” operator symbol was previously assigned in error and was 
changed to the “≥” operator symbol. 
 
Section 8.2, Exclusion Criteria 
Change:  Criterion #1 was modified. 
Now reads: 
1. 
Hypoxemia (oxygen saturation <96% awake or asleep without any supplemental 
oxygen or respiratory support, or for altitudes >1000 m, oxygen saturation of <92% 
awake or asleep without any supplemental oxygen or respiratory support). 
Rationale:  The threshold for this test was adjusted to account for sites at higher elevations. 
 
Change:  Criterion #9 was added. 
Now reads: 
9. 
Diagnosis of neonatal Respiratory Distress Syndrome requiring surfactant 
replacement therapy or invasive ventilatory support. 

Protocol 232SM201, Version 3 
 
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9 
Rationale:  This exclusion criterion was added as the risk for Respiratory Distress Syndrome 
(RDS) increases with lower gestational age.  RDS can decrease respiratory function and 
therefore could adversely impact ascertainment of the primary endpoint. 
 
Section 11.1, Regimen 
Change:  A clarifying sentence was added. 
Now reads: 
The volume of the injection, and thus, the dose, will be adjusted for the subject’s age on the day 
of dosing, such that each subject will receive a 12-mg scaled equivalent dose based on CSF 
volume scaling (Table 3).  Thus, younger subjects will be given a lower dose of drug, achieved 
by injecting a smaller volume that is proportional to estimated CSF volume for age, such that 
dose volume will be equivalent to 5 mL for a 2-year-old child to adult.  All subjects’ age must 
be equivalent to ≥37 weeks gestational age at the time of the first dose. 
Rationale:  This sentence was added to clarify that no subject can be dosed prior to reaching age 
equivalent to ≥37 weeks of gestational age.  This requirement will allow twins born between 34 
and 37 weeks of gestation the opportunity to grow in size and to attain cerebrospinal fluid 
volume approximately equivalent to infants born ≥37 weeks of gestation at the time of the first 
dose. 
 
Section 14.2, Laboratory Safety Assessments 
Change:  Clarity regarding blood collection and testing for infants with differing body weight 
categories at Screening was added. 
Now reads: 
The following laboratory tests will be performed to evaluate the safety profile of ISIS 396443: 
 Hematology:  red blood cells, hemoglobin, hematocrit, platelets, white blood cells, 
white blood cell differential 
 Blood chemistry:  total protein, albumin, creatinine, cystatin C, creatine 
phosphokinase, blood urea nitrogen, total bilirubin (direct and indirect), alkaline 
phosphatase, alanine aminotransferase, aspartate aminotransferase, glucose, calcium, 
phosphorus, chloride, sodium, potassium 
 Urinalysis:  specific gravity, pH, protein, glucose, ketones, bilirubin, red blood cells, 
white blood cells, epithelial cells, bacteria, casts, crystals 

Protocol 232SM201, Version 3 
 
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 Cystatin C (for subjects with Screening weight of ≥3 kg) 
 Coagulation (performed at local labs):  aPTT, PT, INR 
Due to blood collection volume limitations for newborns, the laboratory safety assessments 
described above will be performed according to the schedules listed in Table 3 and 4.  
Table 3: 
Safety Labs Blood Collection Schedule for Subjects with a Screening Weight 
of ≥3 kg 
Panel/Test 
Screening1 
Day 1 
Day 29 
Day 64 
Day 183, D183, 
D302, D421, 
D540, D659, 
D778 (±7D) 
D365, D700, 
D868 (±7D), and 
Early Term 
Hematology 
X 
 
X 
X 
X 
X 
Serum 
Chemistry 
X 
 
X 
X 
X 
X 
Cystatin C 
X 
 
 
X2 
X2 
X 
Coagulation 
X3 
 
 
 
 
 
1 Screening labs will be collected over a 2 or more day period. 
2 At Day 183 or when the subject’s weight is ≥5.4 kg, whichever comes first, the blood collection schedule will 
revert to that outlined in Section 4. 
3 Coagulation testing must be reviewed prior to dosing on Day 1. 
 
Table 4: 
Safety Labs Blood Collection Schedule for Subjects with a Screening Weight 
of < 3 kg 
Panel/Test 
Screening1 
Day 1 
Day 29 
Day 64 
Day 183, D183, 
D302, D421, 
D540, D659, 
D778 (±7D) 
D365, D700, 
D868 (±7D), and 
Early Term 
Hematology 
X 
 
 
 
X 
X 
Serum 
Chemistry 
X 
 
X 
X 
X 
X 
Coagulation 
 
X2 
 
 
 
 
1 Screening labs will be collected over a 2 or more day period. 
2 Coagulation testing must be performed and reviewed prior to dosing on Day 1. 
 
 
 

Protocol 232SM201, Version 3 
 
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Biogen Idec MA Inc. 
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Rationale:  These tabular summaries of the sampling schedule for subjects with different weight 
categories clarify the requirements for each category due to blood volume restrictions at lower 
Screening weights.  Cystatin C testing was removed for infants <3 kg at Screening due to blood 
collection volume restrictions. 
 

Protocol 232SM201, Version 3 
 
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Biogen Idec MA Inc. 
12 
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. 

CONFIDENTIAL 
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen Idec Inc. 
1 
 
 
 
 
 
 
 
 
 
 
Biogen Idec MA Inc. 
14 Cambridge Center 
Cambridge, MA 02142, USA 
 
Biogen Idec Research Limited 
Innovation House 
70 Norden Road 
Maidenhead Berkshire 
SL6 4AY 
United Kingdom 
 
 
______________________________________________________________________ 
AMENDMENT SUMMARY 
Biogen Idec Protocol 232SM201 
An Open-Label Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of 
Multiple Doses of ISIS 396443 Delivered Intrathecally to Subjects With Genetically Diagnosed 
and Presymptomatic Spinal Muscular Atrophy 
Version 2 
Date:  23 October 2014 
EUDRA CT Number:  2014-002098-12 
Version 2 of the protocol has been prepared for this amendment, which supersedes Version 1. 

Protocol 232SM201, Version 2 
CONFIDENTIAL 
The information contained herein may not be used, disclosed, or published without the written consent of 
Biogen Idec Inc. 
3 
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 15.3.1, Adverse Events  
Change:  It was added that adverse events (AEs) will be collected on the case report form (CRF) 
from the time of signing the informed consent form (ICF). 
Now reads:   
For subjects who receive study treatment, any AE experienced by the subject between the 
time of first dose of study treatmentsigning the ICF and Final Study Visit/Telephone Call is to 
be recorded on the CRF, regardless of the severity of the event or its relationship to study 
treatment.  For subjects who never receive study treatment, no AEs need to be recorded on 
the applicable CRF.   
An AE that is ongoing when the subject completes or discontinues the study should be followed 
by the Investigator, if possible, until the event has resolved or stabilized.   
Rationale:  To be consistent across all the studies in the spinal muscular atrophy program, the 
AEs will be collected in the CRF from the time of signing the ICF instead of from the first dose.   
This change also affects Section 4, Schedule of Events for Study 232SM201, Table 1 (Schedule 
of Activities), footnote 21.   
Section 15.3.2, Serious Adverse Events  
Change:  It was added that the serious adverse events (SAEs) will be also be collected in the 
CRF from the time of signing the ICF. 
Now reads:   
For subjects who receive study treatment, any SAE experienced by the subject between the 
time of the signing of the ICF and Final Study Visit/Telephone Call is to be recorded on an SAE 
form and on the applicable CRF, regardless of the severity of the event or its relationship to 
study treatment.  For subjects who never receive study treatment, any SAE occurring 
between the time of signing the ICF and Final Study Visit/Telephone Call must be recorded 
on an SAE form, regardless of the severity of the event or its relationship to study 
treatment; however, the SAE does not need to be recorded on the applicable CRF.   
SAEs must be reported to SynteractHCR Safety (Fax: +1-760-268-6500; Email: 
safetyfax@synteracthcr.com) within 24 hours as described in Section 15.3.3.  Follow-up 
information regarding an SAE also must be reported with 24 hours. 
Subjects will be followed for all SAEs until their Final Study Visit/Telephone Call.  Thereafter, 
the event should be reported to SynteractHCR Safety only if the Investigator considers the SAE 
to be related to study treatment. 
Any SAE that is ongoing when the subject completes or discontinues the study will be followed 
by the Investigator until the event has resolved, stabilized, or returned to baseline status. 

Protocol 232SM201, Version 2 
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Rationale:  Additional language was added to ensure that besides recording the SAEs in the 
safety database from the signing of the ICF, the SAEs will also be recorded in the clinical 
database via the CRFs.  
This change also affects Section 4, Schedule of Events for Study 232SM201, Table 1 (Schedule 
of Activities), footnote 21. 

Protocol 232SM201, Version 2 
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5 
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. 
 Based on the pharmacokinetic (PK) sampling schedule in Section 4, Schedule of 
Events for Study 232SM201, Table 1 (Schedule of Activities), the PK sample 
collection at 4 h (±1 h) after the injection of study treatment will occur only on 
Study Day 64.  A statement was added to Section 4, Schedule of Events for 
Study 232SM201, Table 1 (Schedule of Activities), footnote 15 to clarify this 
schedule.  Footnote 15 in Table 1 now reads:  Plasma PK only collected before the 
injection of study treatment only on Study Days 64, 183, 302, 540, 659, and 778.  
Plasma PK collected 4 h (±1 h) after the injection of study treatment only on 
Study Day 64. 
 To be consistent with Section 11.5.2, Concomitant Procedures, footnote 20 was added 
to Section 4, Schedule of Events for Study 232SM201, Table 1 (Schedule of 
Activities) to clarify that “In addition to concomitant medications, ancillary 
procedures will be recorded.” 
 In Section 8.2, Exclusion Criteria, Exclusion Criterion 8, and Section 11.5.1, 
Concomitant Therapy, Disallowed Concomitant Therapy, olesoxime was removed 
from the examples provided for the experimental agents that the subjects were 
prohibited from receiving during the study.