A PHASE 1B MULTICENTER, OPEN-LABEL, SINGLE ASCENDING DOSE STUDY TO EVALUATE THE SAFETY AND TOLERABILITY OF PF-06939926 IN AMBULATORY AND NON-AMBULATORY SUBJECTS WITH DUCHENNE MUSCULAR DYSTROPHY
Phase: PHASE1
Conditions: Duchenne Muscular Dystrophy
Sponsor: Pfizer

PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 1
A PHASE 1B MULTICENTER, OPEN-LABEL, SINGLE ASCENDING DOSE 
STUDY TO EVALUATE THE SAFETY AND TOLERABILITY OF PF-06939926 IN 
AMBULATORY AND NON-AMBULATORY SUBJECTS WITH DUCHENNE 
MUSCULAR DYSTROPHY 
Investigational Product Number:
PF-06939926
Investigational Product Name:
Not Applicable (NA)
United States (US) Investigational New 
Drug (IND) Number:
European Clinical Trials Database 
(EudraCT) Number:
NA
Protocol Number:
C3391001
Phase:
1b
This document and accompanying materials contain confidential information belonging to Pfizer.  
Except as otherwise agreed to in writing, by accepting or reviewing these documents, you agree to hold 
this information in confidence and not copy or disclose it to others (except where required by applicable 
law) or use it for unauthorized purposes.  In the event of any actual or suspected breach of this 
obligation, Pfizer must be promptly notified.
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Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 2
Document History
Document
Version Date
Summary of Changes and Rationale
Amendment 9
07 March 2022
In Sections 1.4, 3.1, 3.2, and 9.1, changed the 
total N number to 22 which is the number of 
subjects who were dosed.

Rationale: The C3391001 study will no longer 
enroll subjects.
In Section 7.2.12 (cTnI), added new parameters 
for the troponin level for the triggers to
implement additional safety monitoring.

Rationale: Given that the central laboratory is 
using a new cardiac troponin assay (Beckman) 
with a different upper limit of normal (ULN) 
than that previously used (Centaur), the 
instructions for further assessments of 
subjects with an absolute level of cardiac 
troponin of >0.5 ng/mL are now presented as 
the difference between the most recent value 
of cardiac troponin and the ULN, and not an 
absolute value.  The current criterion is 
equivalent to the previous one, given that the 
absolute number of >0.5 ng/mL is 17× the 
ULN of the previous assay and the absolute 
number of >1.0 ng/mL is 33× the ULN.
In Section 8.4.3.1, added the following 
paragraphs:

A male family member or healthcare 
provider who has been exposed to the 
study intervention by skin, mucosal 
contact, or ingestion then exposes his 
female partner prior to or around the time 
of conception.

A female household member of a study 
subject reports that she is pregnant and has 
been exposed through viral shedding by a 
study subject within 2 months after 

PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 3
Document
Version Date
Summary of Changes and Rationale
dosing, and a month prior to or during 
pregnancy.

Rationale: For consistency with the Phase 3 
study.
In Section 13.1, updated “primary completion 
date” to “end of trial.”

Rationale: Clarification based on the 
definition of primary completion date.
In Appendix 1, added statement to indicate 
summary statistics will be generated for a cohort 
of at least 3 subjects.

Rationale: To provide clarity as to when a 
statistical summary would be generated for 
the sirolimus cohort.
Appendix 1 (Changes that were made via the
PACL dated 24-Nov-2021):
Added a footnote to the Sirolimus SoA to indicate 
that a phone communication between the site staff 
and the subject and/or caregiver will be conducted 
to remind the subject to start taking the sirolimus 
if dispensed at baseline.

Rationale: To add clarity.
Removed “Dosing + 24 Hour Monitoring + Initial 
Follow-Up” from the Visit 3 header in the 
Sirolimus SoA.

Rationale: To add clarity. Visit 3 in the main 
SoA includes days 1, 2, 4, 7, and 10 which 
applies to dosing, monitoring, and follow-up 
after PF-06939926 administration.  The 
activity to be conducted during Visit 3 for the 
sirolimus cohort is to obtain the trough level 
on Day 4. As such, text referring to dosing of 
PF-06939926 and 24 hour monitoring are not 
relevant and could be misleading.

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Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 4
This amendment incorporates all revisions to date, including amendments made at the 
request of country health authorities and institutional review boards (IRBs)/ethics committees 
(ECs). 

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Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
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TABLE OF CONTENTS
LIST OF TABLES...................................................................................................................11
LIST OF FIGURES .................................................................................................................11
APPENDICES .........................................................................................................................11
SCHEDULE OF ACTIVITIES................................................................................................12
1. INTRODUCTION ...............................................................................................................25
1.1. Mechanism of Action/Indication.............................................................................25
1.2. Background and Rationale ......................................................................................25
1.2.1. Duchenne Muscular Dystrophy..................................................................25
1.2.2. Dystrophin Role in Muscle.........................................................................26
1.2.3. Gene Therapy for the Treatment of DMD..................................................28
1.3. Immunogenicity Risk Assessment ..........................................................................29
1.3.1. Nonclinical Immunogenicity ......................................................................29
1.3.2. Nonclinical Pharmacodynamics .................................................................30
1.4. Study Design Rationale...........................................................................................30
1.4.1. Rationale for Dosage Selection and Method of Administration.................30
1.4.2. Rationale for Collection of Muscle Biopsies..............................................31
1.4.3. Rationale for Selected Patient Population ..................................................31
1.5. Anticipated Risks and Safety Monitoring ...............................................................32
1.5.1. Hepatic Injury.............................................................................................32
1.5.2. Immunogenicity to AAV and transgene.....................................................33
1.5.3. Other Risks .................................................................................................34
1.5.4. Other Safety Monitoring.............................................................................34
1.6. Other........................................................................................................................35
2. STUDY OBJECTIVES AND ENDPOINTS.......................................................................36
3. STUDY DESIGN.................................................................................................................38
3.1. Study Overview.......................................................................................................38
3.2. Planned Number of Subjects...................................................................................39
3.3. Duration of Subject Participation............................................................................40
3.4. Approximate Duration of Study..............................................................................40
3.5. Dose Progression and Stopping Rules ....................................................................40
4. SUBJECT ELIGIBILITY CRITERIA.................................................................................41

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4.1. Inclusion Criteria.....................................................................................................42
4.2. Exclusion Criteria....................................................................................................43
4.3. Caregiver(s).............................................................................................................46
4.4. Re-screening............................................................................................................46
4.5. Lifestyle Requirements ...........................................................................................47
4.5.1. Activity .......................................................................................................47
4.5.2. Contraception..............................................................................................47
4.6. Sponsor’s Qualified Medical Personnel..................................................................48
5. STUDY TREATMENTS.....................................................................................................48
5.1. Allocation to Treatment ..........................................................................................49
5.2. Subject Compliance.................................................................................................50
5.3. Investigational Product Supplies.............................................................................50
5.3.1. Dosage Form(s) and Packaging..................................................................50
5.3.2. Preparation and Dispensing........................................................................51
5.4. Investigational Product Administration ..................................................................51
5.5. Investigational Product Storage ..............................................................................52
5.6. Investigational Product Accountability...................................................................53
5.6.1. Destruction of Investigational Product Supplies ........................................53
5.7. Concomitant Treatment(s).......................................................................................53
5.7.1. Permitted Therapies....................................................................................53
5.7.2. Prohibited Therapies...................................................................................54
5.8. Rescue Medication ..................................................................................................55
6. STUDY PROCEDURES BY VISIT ...................................................................................56
6.1. Visit 1 (Screening): Days -196 to -17 .....................................................................56
6.2. Visit 2 (Baseline): Day -16 (-12 to +2 days)...........................................................59
6.3. Visit 3 (Dosing): Day 1 ±24-hour Monitoring during In-patient Stay (ie, Day 
2), and Days 4, 7, and 10 (±1 Day) ...........................................................................61
6.4. Visit 4 (Week 2): Day 14 ±1 Day ...........................................................................64
6.5. Remote Visits 5, 7, 9, 11.1, 11.2, 11.3, 12.1, 12.2 (Weeks 3, 6, 10, 15, 19, 
22, 32, 39): Days 21, 45, 75 ±3 Days, and Days 106, 135, 155, 225, 270 ±7 
Days...........................................................................................................................65
6.6. Visit 6 (Week 4): Day 30 ±3 Days..........................................................................66
6.7. Visit 8 (Week 8): Day 60 ±3 Days..........................................................................66

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PFIZER CONFIDENTIAL
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6.8. Visit 10 (Week 12): Day 90 ±3 days.......................................................................67
6.9. Visit 12 (Week 26): Day 180 ±7 Days....................................................................68
6.10. Visit 13 (Week 52): Day 360 ±7 Days..................................................................70
6.11. Visits 14, 15, 16, 17 (Long-term Follow-up Phase Years 2-5): Annually -
Days 730, 1095, 1460, 1825 ±30 Days or Early Termination ..................................71
6.12. Remote Visits 13.1, 14.1, 15.1, 16.1 (Long-term Follow-Up Phase Years 
1.5, 2.5, 3.5, 4.5): Days 545, 910, 1275, 1640 ±30 Days..........................................73
6.13. Subject Withdrawal...............................................................................................73
6.13.1. Withdrawal of Consent.............................................................................73
6.13.2. Lost to Follow-up .....................................................................................74
7. STUDY ASSESSMENTS ...................................................................................................74
7.1. Blood Volume .........................................................................................................75
7.2. Safety.......................................................................................................................75
7.2.1. Clinical Laboratory.....................................................................................75
7.2.2. Physical Examinations................................................................................77
7.2.2.1. Brief Physical Examinations.....................................................77
7.2.3. Neurological Examination..........................................................................77
7.2.3.1. Brief Neurological Examination ...............................................78
7.2.4. Height and Weight Measurements..............................................................78
7.2.4.1. Height........................................................................................78
7.2.4.2. Weight .......................................................................................78
7.2.5. Vital Signs ..................................................................................................78
7.2.6. Triplicate Electrocardiogram (ECG) ..........................................................79
7.2.7. Safety Imaging............................................................................................80
7.2.7.1. Management of Incidental Findings..........................................80
7.2.7.2. Cardiac MRI (or Echocardiogram, if necessary) ......................80
7.2.8. Suicidal Ideation and Behavior Assessment...............................................81
7.2.9. Concomitant Medication Monitoring .........................................................82
7.2.9.1. Subject Dosing Diary ................................................................82
7.2.10. Infusion Site Monitoring...........................................................................82
7.2.11. Wellness Check-in....................................................................................82
7.2.12. Triggers for Additional Safety Monitoring...............................................82
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7.6. Muscle Biopsies ......................................................................................................87
 
 
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8. ADVERSE EVENT REPORTING......................................................................................92
8.1. Requirements...........................................................................................................92
8.1.1. Additional Details on Recording Adverse Events on the CRF...................93
8.1.2. Eliciting Adverse Event Information..........................................................94
8.1.3. Withdrawal from the Study Due to Adverse Events (see also the 
Subject Withdrawal section)............................................................................94
8.1.4. Time Period for Collecting AE/SAE Information......................................94
8.1.4.1. Reporting SAEs to Pfizer Safety...............................................94
8.1.4.2. Recording Non-serious AEs and SAEs on the CRF .................94
8.1.5. Causality Assessment .................................................................................95
8.1.6. Sponsor’s Reporting Requirements to Regulatory Authorities ..................95
8.2. Definitions...............................................................................................................95
8.2.1. Adverse Events...........................................................................................95
8.2.2. Abnormal Test Findings .............................................................................96
8.2.3. Serious Adverse Events ..............................................................................96
8.2.4. Hospitalization............................................................................................97
8.3. Severity Assessment................................................................................................98
8.4. Special Situations ....................................................................................................99
8.4.1. Protocol-Specified Serious Adverse Events...............................................99
8.4.2. Potential Cases of Drug-Induced Liver Injury............................................99
8.4.3. Exposure to the Investigational Product during Pregnancy or 
Breastfeeding, and Occupational Exposure...................................................101
8.4.3.1. Exposure during Pregnancy ....................................................101
8.4.3.2. Exposure during Breastfeeding ...............................................103
8.4.3.3. Occupational Exposure ...........................................................103
8.4.4. Medication Errors .....................................................................................103
9. DATA ANALYSIS/STATISTICAL METHODS.............................................................104
9.1. Sample Size Determination...................................................................................104
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9.2. Safety Analysis......................................................................................................104
9.2.1. Derivation of Vital Signs Parameters .......................................................105
9.2.2. Electrocardiogram (ECG) Analysis..........................................................105
9.2.3. Cardiac MRI (or Echocardiogram, if necessary)......................................106
9.3. Analysis of Secondary Pharmacodynamic Endpoints...........................................106
9.5. Interim Analysis ....................................................................................................106
9.6. Data Monitoring Committee .................................................................................106
10. QUALITY CONTROL AND QUALITY ASSURANCE...............................................107
11. DATA HANDLING AND RECORD KEEPING ...........................................................108
11.1. Case Report Forms/Electronic Data Record .......................................................108
11.2. Record Retention.................................................................................................108
12. ETHICS............................................................................................................................109
12.1. Institutional Review Board/Ethics Committee....................................................109
12.2. Ethical Conduct of the Study ..............................................................................109
12.3. Subject Information and Consent........................................................................109
12.4. Reporting of Safety Issues and Serious Breaches of the Protocol or ICH 
GCP .........................................................................................................................110
13. DEFINITION OF END OF TRIAL.................................................................................110
13.1. End of Trial .........................................................................................................110
14. SPONSOR DISCONTINUATION CRITERIA ..............................................................111
15. PUBLICATION OF STUDY RESULTS........................................................................111
15.1. Communication of Results by Pfizer ..................................................................111
15.2. Publications by Investigators ..............................................................................112
16. REFERENCES ................................................................................................................113
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Page 11
LIST OF TABLES
Table 1.
Central Laboratory Tests ..........................................................................76
LIST OF FIGURES
Figure 1.
The Dystrophin-associated Protein (DAP) Complex12.............................27
Figure 2.
Study Schematic .......................................................................................39
APPENDICES
Appendix 1. Cohort to Assess the Effect of Sirolimus on Complement Activation 
Related to PF-06939926 Infusion...........................................................119
Appendix 2. Alternative Measures During Public Emergencies ...........................................127
Appendix 3. Protocol Amendment History ...........................................................................129
Appendix 4. Abbreviations....................................................................................................148

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C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 12
SCHEDULE OF ACTIVITIES
The schedule of activities table provides an overview of the protocol visits and procedures.  Refer to the STUDY PROCEDURES BY 
VISIT and STUDY ASSESSMENTS sections of the protocol for detailed information on each procedure and assessment required for 
compliance with the protocol. 
The investigator may schedule visits (unplanned visits) in addition to those listed on the Schedule of Activities table in order to 
conduct evaluations or assessments required to protect the well-being of the subject.  For the sirolimus cohort, in addition to the 
Schedule of Activities below, see Appendix 1.
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Informed 
consent/assentd
X
Demography
X
Medical and 
Medication 
Historye
X

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Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 13
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Inclusion/
Exclusion Review
X
X - NAb 
onlyi
Physical and 
Neurological 
Examination
X
X
Xf
Xf
Xf
Xf
Xf
Xf
Xf – annual 
and ET 
only
Height and 
Weight
X
Xg
X
X
X
X – annual 
and ET 
only
Vital Signsh
X
X
Xh
Xh
Xh
X
X
X
X
X – annual 
and ET 
only
Triplicate ECG
X
Xv – Day 
1 only
X
X
X
X
X
X – annual 
and ET 
only
Laboratory Assessments
Blood samplesx

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Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 14
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Clinical safetyk
Xk,l
Xl
Xj,k –also 
includes 
local labs 
Days 5-9
Xk
Xk
Xk
Xk
Xk
X
X
X
X
X
X
Xt
Exploratory 
biomarkers
(serum, plasma, 
RNA)
Xx
Xx
Xx –
plasma 
and serum 
on Days 4, 
7, 10
Xx– plasma 
and serum
Xx-
plasma 
and 
serum
Xx
X
X
Xt
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Page 15
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Urine samples
 
 
Tissue samples
Muscle biopsyn
Xn #1
Xo
#2a
Xo
#2b
Xo
#3a
Xo
#3b
X-ET onlyo
Various
 
 
 
Imaging Assessmentsa,q
 
 
 
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PFIZER CONFIDENTIAL
Page 16
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Cardiac MRIp
X
X
X – annual 
and ET 
only
Functional Assessmentsa,q
 
 
 
 
 
 
 
 
Questionnairesr
C-SSRS
X
X
X
X
X
X – annual 
and ET 
only
 
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PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 17
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
Subject dosing 
diaryu
X – starts 
Day 2


X

X

X
Enrollment
Registration
Xg
Study Treatment
Pre-/post-dose 
concomitant 
glucocorticoid 
medications
X






X
Study drug 
administrationb
X – Day 1 
only
Meningococcal 
Vaccinea
X
X
Ongoing monitoring
Wellness check-in
X
X
X
X
X
X
X
Xt
Concomitant med 
monitoring
Xaa














PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 18
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
AE, and infusion 
site monitoringb
X
→
→
→
→
→
→
→
→
→
→
→
→
→
→
Abbreviations/Acronyms: →= continuous monitoring/event;
 ADA=anti-drug antibody; AE=Adverse events; 
BP=Blood pressure; C-SSRS=Columbia Suicide Severity Rating Scale, ECG = electrocardiogram; ELISpot= Enzyme-Linked ImmunoSpot; 
EQ-5D-5L= EuroQuol 5 Dimensions-5 Levels; ET=early termination; GLDH=glutamate dehydrogenase; HR=heart rate; med=medication(s); 
MRI=magnetic resonance imaging; NAb=neutralizing antibodies; Prep D1.5=whole blood for deoxyribonucleic acid (DNA); NSAA=North Star Ambulatory Assessment; 
RNA=ribonucleic acid; temp=temperature; 
a.
Subjects may be asked to return to the investigational site 2 or 3 times for visits at which biopsies, imaging, and/or functional assessments are required. 
Meningococcal Vaccine: Subjects who have no contraindications and who have not previously received a MenACWY vaccination; or whose last vaccination at the time of 
the Screening visit (Visit 1) is outside the time period of active coverage specified by the vaccine manufacturer (Visit 1) must receive at least 1 dose of MenACWY 
vaccine as early as possible in the Screening Period and not later than 30 days before study drug administration (see Section 5.7.1). Subjects must also receive MenB 
vaccination if indicated by national vaccination guidelines. In addition, local eculizumab prescribing information and other requirements must also be followed (see 
Section 5.8).
b.
Subjects will be admitted to the investigational site to receive a single intravenous infusion of PF-06939926 administered over approximately 2 to 4 hours (+30 minutes 
including flush) on the Dosing visit (ie, Day 1), as detailed in the Investigational Product Manual, and will be monitored for at least 24 hours following study drug 
administration (ie, Day 2), or longer if deemed necessary.  If adverse events (AEs) possibly related to PF-06939926 are observed, subjects should not be discharged until 
the events have resolved or can be managed by the subject and/or caregiver (eg, oral antiemetics are confirmed to effectively stop vomiting events).  Upon discharge, 
CCI
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CCI
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PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 19
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
subjects should stay near the investigational site to enable easy follow-up in the event of any emergent AEs through the Day 14 (Week 2) visit, or longer if clinically 
indicated.  Subjects will return to the investigational site on Days 4, 7, 10 (±1 day) for biospecimen collection, as well as assessment of any new or worsening adverse 
events, changes to concomitant medications, and confirmation of adequate fluid intake and urine output through Week 4.  Blood and urine samples will also be obtained 
for local testing on Days 5-9, or longer, as clinically indicated.  Subjects will be monitored for signs of infusion site reactions from the start of treatment of PF-06939926 
and then at the in-person visits through Week 8 (Day 60 ±3 days), and/or as clinically indicated.
c.
Unless clinical concern and/or subject preference warrants in-person visit, remote visits may be performed at Weeks 3, 6, 10, 15, 19, 22, 32 and 39 (ie, Visits 5, 7, 9, 11.1, 
11.2, 11.3, 12.1, and 12.2, respectively), which would include blood, saliva, and urine collection at the subject’s home coordinated by local phlebotomist, as well as phone 
or email communication between site staff and subject and/or caregiver to discuss any adverse events and/or changes to concomitant medications.  Adequate fluid intake 
and output may also be remotely confirmed during the Week 3 communication. 
d.
Informed consent must be provided by the subject, depending on age, or legally authorized representative (eg, parent or legal guardian).  Subjects who are minors may also 
be required to provide assent in compliance with local regulations and institutional review board (IRB) requirements.
e.
Medical history will also include confirmation by genetic testing of the diagnosis of Duchenne muscular dystrophy (DMD).  Medication history must include at least 
6 months of glucocorticoids with 3 months on a stable, daily dose relative to the Baseline visit.
f.
Only brief physical and neurological examinations will be performed post-baseline unless safety concerns warrant full examination.
g.
Amount of study drug shipped to site will occur once the subject is registered (ie, enrolled) following confirmation of eligibility and measurement of body weight at 
Baseline.  The Baseline visit must occur at least 2-4 weeks (14-28 calendar days) prior to the planned Dosing visit.

PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 20
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
h.
Vital signs will always consist of blood pressure, respiration rate, and heart rate, but body temperature will also be obtained with these measurements at the following 
timepoints: within 30 minutes before and approximately 30 minutes, 1, 2, 4, 8, and 24 hours after the start of the infusion, and on Days 4, 7, 10, 14 and 30.  Body 
temperature at additional timepoints may be collected as clinically indicated.
k.
Clinical safety labs are described in Table 1.  Additional safety labs on Days 1 (pre-dose) through Week 8 will include
and will 
continue to be collected until within normal limits or return to baseline. 
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PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 21
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
l.
Screening labs will include the safety labs (Table 1) and the following: DMD genetic testing (if required to confirm DMD diagnosis), anti-hepatitis A immunoglobulin M, 
anti-hepatitis B surface antigen, hepatitis C antibody, antinuclear antibody (ANA), total immunoglobulin G, and international normalized ratio.  If time between Screening 
labs and the planned Baseline visit exceeds 12 weeks (84 days), then all Screening labs except for DMD genetic testing should be repeated and eligibility (re)confirmed 
prior to enrolling the subject.
m.
Urinalysis may be performed at additional planned or unscheduled visits if clinically indicated.
n.
Muscle biopsies (eg, open, needle) will be obtained following administration of an anesthetic (eg, regional block or under general anesthesia) according to institutional 
standard practice and will occur preferably after any imaging and functional assessments scheduled for the same visit.  If baseline muscle biopsies have been obtained 
outside this study and (1) can be shipped to the sponsor’s designated lab for use in this study and (2) are deemed by the sponsor to be of sufficient quantity and quality, 
these may replace the need for an additional baseline biopsy. 
o.
Biopsies will be collected from a single subject at a maximum of 3 visits during the study at the following timepoints: (1) Baseline, (2) either Week 8 (Day 60) or Week 12 
(Day 90), and (3) either Week 26 (Day 180) or Week 52 (Day 360).  If a subject withdraws participation in the study prior to completion of the 1st Year Follow-up, a 
biopsy at the Early Termination visit may only be obtained if subject has not yet completed all 3 procedures. 
p.
Cardiac MRI should be performed after thigh and upper limb MRI and/or on separate days within the required visit window, if preferred by site and/or subject.  Cardiac 
MRI already obtained within 3 months prior to the Screening visit may be deemed adequate for confirming subject eligibility (see Section 6.1).  If cardiac MRI is 
attempted, but is unable to be evaluated (eg, due to young subject’s inability to remain still during the scan), it may either be repeated or substituted by a locally-read 
echocardiogram.

PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 22
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
r.
As described in Section 7.7, depending on factors such as the subject’s age, ambulatory status at enrollment, and at the discretion of the investigator and caregiver, 
questionnaires will be completed by the subjects themselves and/or by the legal caregiver on behalf of the subject.  Legal caregivers will also be asked to complete 
self-assessments.  As per Section 7.2.8, the Columbia Suicide Severity Rating Scale (C-SSRS) will be completed by the legal caregiver on behalf of the subject, or by the 
subject himself depending on his age at Screening (ie, < or ≥12 years of age, respectively). 
s.
Between one and four hours prior to infusion of study drug, subjects will receive Ŏ2 mg/kg intravenous methylprednisolone.  Subjects will replace pre-study daily 
glucocorticoids with oral prednisone or prednisolone at increased daily dose levels for the first 3 months post-dose of study drug, after which, so long as there is no 
immune response or other clinical indication, subjects may return to their pre-study daily glucocorticoid regimen for the remainder of the first year of post-treatment 
(see Section 5).
 
 
u.
Subjects or caregivers on behalf of subjects may be required to complete dosing diaries to ensure compliance with the increased daily dose levels of oral prednisone or 
prednisolone required for at least the first 3 months post-dose of study drug.  If diary is not used, compliance with the daily glucocorticoid regimen is expected to be 
CCI
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PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 23
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
reviewed with the subject and/or caregiver and documented following all in-clinic and remote visits (ie, wellness check-ins) through at least the first year following 
PF-06939926 administration.
v.
On Day 1, triplicate ECGs will be performed approximately one hour prior to infusion of study drug, as well as upon completion of the infusion (+30 minutes) and as 
clinically indicated.
w.
Activity monitors may be placed on the subject’s wrist and/or ankle prior to the other functional assessments and will be worn continuously for the subsequent 2 weeks, 
except for remote visit at Week 39 (Day 270±7 days), in which case activity monitors will be sent directly to the subject’s home for 2-week continuous wear in free-living 
conditions.  No functional tests are expected to be performed at Week 39.  Certain functional assessments will be avoided for subjects who are or become non-ambulatory 
(ie, inability to walk 10 meters unassisted), as described in Section 7.5.
CCI

PF-06939926
C3391001
Final Protocol Amendment 9, 07 March 2022
PFIZER CONFIDENTIAL
Page 24
Period
Screening
Baseline
Treatment
1st Year Follow-up
Long-Term
Follow-up
and/or Early 
Termination
Visit Number
Visit 1a,i
Screening
Visit 
2a,g
Baselin
e
Visit 3b
Dosing +
24 Hour 
Monitor-
ing + 
initial 
follow-up 
Visit 4b
Week 2
Remotec
Visit 5
Week 3
Visit 
6
Wee
k 4
Remotec
Visit 7
Week 6
Visit 
8a
Week 
8
Remotec
Visit 9
Week 10
Visit 
10
Week 
12
Remotec
Visits 
11.1, 
11.2, 11.3
Weeks 
15, 19, 22
Visit 
12a
Wee
k 26
Remotec
Visits 12.1 
and 12.2
Weeks 32, 
39
Visit 
13a
Week 
52
Remotet
visits
13.1, 14.1, 
15.1, 16.1;
Years 1.5, 
2.5, 3.5, 4.5 
Visits 14-17a
Years 2-5
/Early 
Termination 
(ET)
Visit Window
Day -196 
to
Day -17
Day -16
g
(-12 to 
+2 
days)
Day 1, 
Day 2 
(Discharge), 
Days 4j, 7, 
10 (±1 day)
Day 14
(±1 day)
Day 
21
(±3 
days)
Day 
30
(±3 
days
)
Day 
45
(±3 
days)
Day 
60
(±3 
days)
Day 
75
(±3 
days)
Day 
90
(±3 
days
)
Days 
106, 
135, 
155
(±7 
days)
Day 
180
(±7 
days)
Days 
225, 270
(±7 days)
Day 
360
(±7 
days
)
Remote 
Days 545, 
910, 1275, 
1640; Visit 
Days 730, 
1095, 1460, 
1825
(±30 
days)/ET
z.
At Screening, only the functional assessments to confirm eligibility based on a subject’s ambulatory status (ie, Ambulatory status for all subjects, but only NSAA for 
ambulatory subjects, defined as ability to walk 10 meters unassisted and pulmonary function tests and Performance of Upper Limb (PUL), version 2.0 for non-ambulatory 
subjects) will be performed (see Section 6.1).  If time between Screening functional assessments and the planned Baseline visit exceeds 12 weeks (84 days), then these 
should be repeated and eligibility (re)confirmed prior to enrolling the subject.  All functional assessments, including activity monitoring, will be performed at Baseline and 
the visits specified.
aa.
Subjects should receive meningococcal vaccinations at least 30 days prior to administration of PF-06939926 (ie, Baseline visit).  Alternatively, (eg, in the case of allergy) 
prophylactic antibiotics for meningococcus may be provided simultaneously with eculizumab, if administered (see Section 5.8).

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1. INTRODUCTION
1.1. Mechanism of Action/Indication
The investigational product, PF-06939926, is a gene therapy viral construct, 
AAV9.hCK.opti-Dys∆3978.spolyA, that consists of a recombinant adeno-associated virus 
serotype 9 (AAV9) vector with a miniaturized version of the DMD gene which encodes the 
domains minimally required for functionality of the dystrophin protein.  Cardiac and skeletal 
muscle -specific transgene expression is mediated by the synthetic promoter, hybrid creatine 
kinase (hCK).1  This agent is in development for the treatment of Duchenne muscular 
dystrophy (DMD), an X -linked neuromuscular disease primarily affecting boys as described 
in Section 1.2.1.
Protocol C3391001 is the first-in-human (FIH)/first-in-patient (FIP) study with 
PF-06939926.  This study aims to evaluate the safety and tolerability following a single dose 
of PF-06939926 in ambulatory and non-ambulatory subjects with DMD.  Other objectives 
include pharmacodynamics of dystrophin expression and distribution, assessments relevant to 
muscle quality and function and dose selection for future clinical development. 
Complete information for this compound may be found in the Single Reference Safety 
Document, which for this study will be the Investigator’s Brochure (IB).
1.2. Background and Rationale
1.2.1. Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is the most frequently inherited pediatric 
neuromuscular disease and predominantly affects boys.  It is an X-linked muscular dystrophy 
caused by a mutation at Xp21 in the gene coding for the protein dystrophin2 which is absent 
from the muscle of boys with DMD.  The most common forms of mutations that cause DMD 
are large deletion mutations of one or more exons (68%).  However, large duplication 
mutations (11%), point mutations (11%), and small insertion/deletion mutations (7%) also 
occur.3  These gene mutations often lead to a frame shift mutation (ie, disruption of the 
reading frame) or generate a premature stop codon (ie, out-of-frame) and result in a lack of 
dystrophin protein.  The majority of in-frame deletions result in a milder form of the disease, 
Becker muscular dystrophy (BMD), in which patients express a truncated, partially 
functional dystrophin. 
The lack of the dystrophin protein in DMD boys leads to skeletal muscle, and ultimately 
heart and respiratory muscle, degeneration causing premature death.4  Progressive weakness 
and muscle atrophy begin in childhood, starting in the lower legs and pelvis before spreading 
into the upper arms.  Other symptoms include loss of some reflexes, a waddling gait, frequent 
falls, difficulty when rising from a sitting or lying position or when climbing stairs, changes 
to overall posture, impaired breathing, and cardiomyopathy.  Many children are unable to run 
rapidly or to jump.  The atrophied muscles, in particular the calf muscles (and, less 
commonly, muscles in the buttocks, shoulders, and arms), may be enlarged by an 
accumulation of fat and connective tissue, causing them to look larger and healthier than they 
actually are (called pseudohypertrophy).  Bone thinning and scoliosis are common.  
Ultimately, a wheelchair becomes necessary, in most cases between 12 to 15 years of age.5

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There is no specific approved treatment that can stop or reverse the progression of DMD.  
There have been three recent US drug approvals for DMD.  EXONDYS 51™ (eteplirsen) 
was recently approved based on a surrogate endpoint of increased dystrophin protein 
production, but is only indicated for DMD patients that have an exon 51 skip amenable 
mutation which occurs in about 13% of DMD patients.6  VYONDYS 53™(golodirsen) is 
intended to allow the transcription process to skip over exons that contain mutations (‘exon 
skipping’) in the region of exon 53,7 which occurs in approximately 8% of DMD patients.  
EMFLAZA™ (deflazacort) was approved for the treatment of DMD patients 5 years of age 
and older based on improved muscle strength compared to placebo.  Disease management 
consists primarily of supportive care which ranges from physical therapy to maximize 
function and minimize muscle contractures, to orthotics, tendon release surgery (which 
provides temporary benefit as contractures will redevelop), use of wheelchair (usually by 
age 12), surgical correction of scoliosis8 and use of respiratory care including various forms 
of assisted ventilation (including tracheotomy).  Respiratory infections may be treated with 
antibiotics.  Death from pneumonia or cardiac involvement in late teens or early twenties is 
commonly observed in these patients.9,10
A key therapeutic goal is to slow or prevent muscle degeneration in these patients.  Only 
limited approaches, such as chronic glucocorticoid use, are currently available, but 
glucocorticoid use is associated with well known adverse events such as weight gain and 
broad hypothalamic pituitary adrenal axis effects.
1.2.2. Dystrophin Role in Muscle
Dystrophin is a cytoplasmic protein encoded by the DMD gene, which links cytoskeletal 
actin filaments to membrane proteins.  Normally, the dystrophin protein, located primarily in 
skeletal and cardiac muscles, with smaller amounts expressed in the brain, acts as a shock 
absorber during muscle fiber contraction by linking the actin of the contractile apparatus to 
the layer of connective tissue that surrounds each muscle fiber (Figure 1).11,12,13

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Figure 1.
The Dystrophin-associated Protein (DAP) Complex12
Dystrophin acts as an important link between the internal cytoskeleton and the extracellular matrix.  DG, 
-dystroglycan; DG, -dystroglycan. 
The DMD gene is particularly complex and contains at least eight independent and 
tissue-specific promoters.  The full-length dystrophin isoform for instance, is transcribed 
from three independently regulated promoters.14  Apart from the full-length dystrophin 
isoforms (427 kDa), five additional isoforms exist due to splicing of the dystrophin 
ribonucleic acid (RNA).  These additional isoforms are named according to their respective 
molecular weights: Dp260 (predominantly expressed in the retina), Dp140 (expressed in 
central nervous system [CNS] and kidney), Dp116 (detected in the peripheral nervous 
system), Dp71 (expressed in most tissues but not in muscle), and Dp40 (expressed in the 
brain).15-19
In muscle, dystrophin is localized to the cytoplasmic face of the sarcolemma membrane.  
Full-length dystrophin (Dp427) consists of an N-terminal actin-binding domain, a central 
large rod-like domain composed of spectrin-like repeats, and a cysteine rich (CR) C-terminus 
that is connected to the dystrophin-associated glycoprotein complex (DGC), a large protein 
complex that forms a critical link between the cytoskeleton and the extra-cellular matrix.20  
In addition to dystrophin, this complex consists of dystroglycan (and ), sarcoglycan (, , 
and ), sarcospan, syntrophin (1, 1, 2, 1, 2), and -dystrobrevin.21  Alpha and beta 
dystroglycan (dystrophin-associated glycoprotein) bind laminin, a component of the basal 
lamina, and dystrophin respectively, thereby providing a link between the cytoskeleton and 
the extracellular matrix.  Sarcoglycan is the second transmembrane component of the DGC.  
On the cytoplasmic side, the sarcolemmal DGC, through dystrophin, interacts with 
syntrophin and -dystrobrevin.  These latter proteins recruit scaffolding proteins onto which 
signaling proteins and ion channels are anchored in the membrane.22  In this way, the DGC 
both provides a physical and functional connection between the internal and external 
environment of the muscle cell.

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Due to its pivotal role in the structure of muscle cells, dystrophin restoration, or replacement 
via gene transfer, requires generation of some form of the protein able to reassemble the 
DGC and support a mechanically strong link between the extra-cellular matrix and the 
cytoskeleton.23
1.2.3. Gene Therapy for the Treatment of DMD
The muscular dystrophies, and in particular DMD, are attractive candidates for gene transfer, 
as they arise from single-gene mutations.  While many advances have occurred, the 
development of an effective gene therapy for DMD still faces significant challenges.  These 
include in particular (i) determining the optimal mode of gene delivery in order to reach all 
targeted muscle cells, (ii) overcoming the packaging requirements of AAV and 
(iii) overcoming the immune challenges linked to the reintroduction of a gene that may be 
recognized as foreign by the immune system of DMD patients.  The optimized vector, 
PF-06939926, has been designed to overcome such challenges for the treatment of DMD.
In brief, recombinant AAV (rAAV) are based on a non-pathogenic, non-integrative, 
replication deficient member of the parvovirus family.  Recombinant AAV (rAAV) vectors 
are ideal candidates for muscle-directed gene therapy because of (i) their ability to target 
skeletal and cardiac muscle, (ii) the long-term persistence of the vector genome in transduced 
cells, and (iii) their lack of immunotoxicity.24  Gene delivery using a variety of AAV 
serotypes has been investigated in clinical trials for diseases including hemophilia B, alpha-1 
antitrypsin deficiency, lipoprotein lipase deficiency, Pompe disease, heart failure, and several 
muscular dystrophies, including DMD (www.clinicaltrials.gov).  Safety and long-term 
transgene expression has been reported in several of these studies, with no AAV-related 
severe adverse events.25  Finally, the AAV9 capsid has been shown to have a strong and 
efficient tropism for both skeletal and cardiac muscle, resulting in transduction throughout 
the body after systemic administration in several preclinical studies.26-29
As mentioned, a major hurdle in the use of rAAV vectors in DMD gene therapy is their 
packaging capacity, which is about 4.7 kb, while the size of the dystrophin complimentary 
deoxyribonucleic acid (cDNA) is about 14 kb.  To overcome this challenge, a number of 
groups have developed partially deleted (3.7–4.5 kb) but highly functional dystrophin genes 
that can be successfully packaged inside rAAV vectors.24,30,31  Dystrophin mini-or 
micro-genes have been designed on the basis of the mutant form of the gene carried in a 
mildly affected patient with BMD.  This form has a large in-frame rod domain deletion and 
fits into AAV vectors even when muscle-specific promoters are incorporated.24,31,32
The truncated dystrophin proteins, called mini or micro-dystrophins, encoded by the rAAV 
vectors, have been shown to improve the dystrophic phenotype in animal models of 
DMD.24,26,32-35  Restoration of the dystrophin-associated protein complex, stabilization of 
muscle degeneration, and improvements in muscle function have been demonstrated 
following delivery of truncated dystrophin genes at different stages of disease progression in 
the murine model for DMD (mdx mice).36,37,38  However, the ability of these minimized 
dystrophin proteins to protect muscle from contraction-induced injury is linked both to the 
structural elements included and to the expression levels of the therapeutic protein.34

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The first clinical trial of muscle-directed delivery of Dys3990, under the control of 
cytomegalovirus (CMV) promoter and packaged in a chimeric AAV capsid, AAV2.5, was 
conducted in DMD patients.39  This placebo-controlled Phase 1 trial involved the unilateral 
injection of 6E+11 or 3E+12 vector genomes (vg) to the biceps muscle of six male subjects 
(5 to 11 years old) with DMD.  Saline or empty capsid was injected into the contralateral 
arm.  All subjects received 2 mg/kg intravenous (IV) methylprednisolone four hours pre- and 
24 and 48 hours post-vector injection to reduce the potential for local inflammation.  The 
treatment was well-tolerated, with no acute or chronic product-related adverse events 
reported.  Notably, no elevations from baseline of creatine kinase, alkaline phosphatase or 
liver enzymes were observed.  Transgene DNA was detected in muscle biopsies of the 
injected, but not contralateral, arm of all six subjects.  However, limited 
mini-dystrophin-positive myofibers were detected in only two of the six treated subjects, one 
each at the low and high dose.  Mini-dystrophin specific T-cells were detected in three of the 
six subjects.40  The lack of mini-dystrophin expression in the treated subjects could be 
explained by many factors, including loss of transduced cells due to disease-associated 
inflammation or a T-cell mediated response primed either by the expressed mini-dystrophin 
protein or prior endogenous revertant dystrophin epitopes.  Alternative explanations for low 
transgene expression include silencing of the CMV promoter or low transduction efficiency 
of AAV2.5 either due to pre-existing neutralizing antibodies (NAb) or low capsid tropism in 
human muscle tissue.
The intramuscular (IM) route of administration (ROA) examined in this first mini-dystrophin 
gene transfer study has several limitations for the treatment of DMD.  The ROA has been 
shown to influence the immune response to rAAV vector encoded transgene expression in 
non-human primate muscle, with immune-mediated destruction of transduced muscle 
observed after direct, but not regional IV (isolated limb perfusion), rAAV delivery.41  
Therefore, the impact of the IM ROA on the low level of transgene expression cannot be 
ruled out, especially since the disease progresses and muscle destruction continues.  
Furthermore, successful treatment of DMD will require global correction of skeletal and 
cardiac muscle that cannot be achieved by IM administration.  While it has been shown that 
widespread vector distribution to the injected muscle can be achieved after isolated limb 
perfusion but not IM delivery, global transduction of skeletal and cardiac muscle would be 
achievable following systemic delivery of a rAAV vector capable of efficiently transducing 
both skeletal and cardiac muscle.42  Thus, the vector construct of PF-06939926 used in this 
Phase 1b DMD clinical trial described above has been further optimized to overcome gene 
therapy challenges for the treatment of DMD.
1.3. Immunogenicity Risk Assessment
1.3.1. Nonclinical Immunogenicity
During the evaluation of systemic delivery of PF-06939926 at various doses in the DMD rat 
model, human mini-dystrophin was seen by the host immune system; however, the humoral 
response detected against mini-dystrophin and the AAV9 capsid had no impact on the 
therapeutic efficacy of the PF-06939926 3- and 6-months post-infusion.  In addition, there 
was no correlation between the lack of a cellular immune response to the transgene and the 
humoral response observed.  The association of systemic delivery of an AAV encoding for a 

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foreign polypeptide with the destruction of the transduced cells by a detectable cellular 
immunity is unclear.67  The route of administration is believed to be an important component 
of immune response outcome with the IV route being the least immunogenic, at least in 
animal models, including rodents, dogs and non-human primates.
1.3.2. Nonclinical Pharmacodynamics
A dose-finding study was conducted in DMD rats and demonstrated a dose-dependent 
increase the percentage of fibers expressing mini-dystrophin as well as a decrease in fibrosis.  
Additionally, increasing doses of vector resulted in a dose-dependent decrease in fatigue as 
measured by repeat grip testing in the DMD rats.  The data from this dose range study in 
DMD rats suggest that 1E+14 vg/kg is the minimally effective dose. 
 Additionally, expression of the transgene in muscle 
tissues and preservation of the functional responses persisted 6 months post-dose. 
1.4. Study Design Rationale
This FIH/FIP study will evaluate the safety and tolerability of a single administration of up to 
3 dose levels of PF-06939926 in ambulatory and non-ambulatory subjects diagnosed with 
DMD with an absence of neutralizing antibodies (NAb) to AAV9.  Up to approximately 
22 subjects may be enrolled to enable a robust understanding of the safety profile of 
PF-06939926.  Additionally, this study will provide information on this gene transfer 
approach by assessing the expression and distribution of mini-dystrophin protein in the 
muscle of subjects with DMD.  The study will be conducted in two phases: (1) the 1st Year 
Follow-up to primarily assess safety, as well as expression and distribution of 
mini-dystrophin at 2 or 3 and 6 or 12 months, and (2) the Long-Term Follow-up to assess 
safety and pharmacodynamics for an additional four years. 
1.4.1. Rationale for Dosage Selection and Method of Administration
Intravenous administration for efficient muscle transduction and the planned starting dose of 
1E+14 vg/kg for the proposed clinical trial were based on the results of the animal 
dose-finding study (Section 1.3.2).  Specifically, data from the dose finding study in the 
DMD rat model showed efficacy, with partial normalization of the percentage of muscle 
fibers expressing the human mini-dystrophin polypeptide, improvement of the tissue 
architecture of skeletal muscles and heart, improved muscle strength and endurance, and 
improvement of the cardiac diastolic function obtained at a minimal dose of 1E+14 vg/kg.  In 
the DMD rat study (Section 1.3.2), 1E+14 vg/kg was well tolerated. 
The planned second dose level of 3E+14 vg/kg for the proposed clinical study is further 
supported by the animal dose-finding study, with the three-fold increase in dose being 
associated with increased transduction and dystrophin expression in muscles.  This dose was 
determined to be the no observed adverse effect level (NOAEL) in a juvenile rat toxicology 
study.  However, should a dose-limiting toxicity be identified at this highest dose, subsequent 
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subjects of this cohort may receive a slightly lower dose of PF-06939926 at 2E+14 vg/kg or 
lower depending on titer method used to assess drug concentration.
The assay originally used to determine the drug concentration of PF-06939926 was based on 
the detection of the inverted terminal repeats (ITR) within the vector DNA sequence.  In 
response to regulatory request, a more precise transgene (TG)-based method for assessing 
drug concentration has been developed.  For the PF-06939926 lots used in the toxicology 
studies used for dose selection, the drug concentration measurements were consistent 
between the ITR- and TG-based titer methods.  However, for the clinical investigational 
product (ie good manufacturing practices [GMP]) lots, PF-06939926 at 3E+14 vg/kg per the 
ITR-based titer method is approximately equivalent to 2E+14 vg/kg per the TG-titer method.  
Therefore, formal switch to the TG-based titer method per regulatory request at the second 
dose level, ie, PF-06939926 2E+14 vg/kg, would be in name only, and not actually a de-
escalation in dose.
1.4.2. Rationale for Collection of Muscle Biopsies
This clinical trial includes up to three muscle biopsy procedures from study subjects: 
potentially one at Baseline, and then up to two post-infusion biopsies to assess the 
distribution and amount of mini-dystrophin and the persistence of transgene expression. If 
less than 3 biopsies are to be collected, the number and timing of biopsy collection will be 
instructed by Pfizer to site staff in writing.  Muscle biopsies will be assessed for dystrophin 
expression by Western blot and/or liquid chromatography-mass spectrometry (LC-MS) and 
immunofluorescence staining (IFS) and will be critical to the demonstration of active 
pharmacology of the vector.  These biopsies may also be assessed for transduction by 
quantitative polymerase chain reaction (qPCR) and messenger ribonucleic acid expression of 
the transgene by reverse transcription-polymerase chain reaction. 
1.4.3. Rationale for Selected Patient Population
In order to evaluate the transduction efficiency of PF-06939926, human subjects must have 
adequate muscle for biopsy.  In ambulatory DMD subjects, skeletal muscle exhibits fibrosis 
and regenerative lesions.  At around the age of six years, the muscle tissue in the lower limbs 
begins to lose the ability to regenerate and the degenerative process becomes dominant.  As 
necrosis continues, adipose tissue replaces muscle tissue, leading to the loss of ambulation.42  
Typically, a wheelchair becomes necessary in most cases between 12 to 15 years of age,5 but 
can occur as late as 16 years of age.43  Thus, for the ambulatory population, the age range of 
4-12 years in this study, along with adequate functional ability (ie, ability to rise from floor in 
≤7 seconds and walk 10 meters unassisted) should encompass subjects who will remain 
ambulant for at least 12 months and should have adequate muscle for transduction and for 
tissue biopsy for the detection of dystrophin expression.47
The non-ambulatory population represents a large (approximately 50%) and growing 
proportion of the prevalent DMD patient population which is often underserved in clinical 
trials.44,45  Non-ambulatory patients have more severe disease including scoliosis, increased 
risk of respiratory impairment, deterioration of cardiac function, reduced limited upper limb 
function, and absence of lower extremity function.  The near absence of the dystrophin 

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protein in cardiac and skeletal muscles, including those required for respiration, leads to the 
morbidity and mortality that characterize this disorder. The aim of gene therapy is to restore 
functional dystrophin in skeletal and cardiac muscle cells by expressing mini-dystrophin 
from the transgene and to achieve protein levels that could translate to a meaningful clinical 
result, including improvement or stabilization of function.  The non-ambulatory population 
for this study is defined by the inability to walk 10 meters unassisted with no age range other 
than a loss of ambulation occurring at <17 years of age, to ensure consistency with a clinical 
phenotype of DMD.  A maximum body weight has been set at 75 kg to limit the total vector 
genomes administered to any subject, given the unknown safety risk of high viral loads, 
especially in those for whom disease is more progressed.  Baseline functional criteria are 
included to ensure that subjects have adequate muscle for biopsy and can participate safely in 
this study.  
1.5. Anticipated Risks and Safety Monitoring
Complete information for this compound, including new potential safety risks identified 
during this FIH/FIP study, may be found in the Single Reference Safety Document, which for 
this study will be the IB.
1.5.1. Hepatic Injury
A number of on-going or completed clinical trials with AAV-based vectors have 
demonstrated the relative safety of this approach to treat various diseases such as hemophilia, 
spinal muscular atrophy (SMA) and other genetic disorders.  The most consistent 
treatment-emergent adverse reaction has been elevations in liver enzymes, mostly related to 
high (>1E+12 vg/kg) vector doses.  The timing of the asymptomatic liver enzyme elevations 
post-gene transfer has varied, but most have been adequately treated with the addition of 
corticosteroids with no impact on transgene expression.48,68  Additionally, subjects treated 
with AAV-based vectors typically generate an immune response to the AAV capsid and may 
develop a cellular response to the transgene.40,49  In an attempt to reduce any inflammatory 
and immune responses to the vector, subjects in an ongoing trial are now receiving steroids 
for several weeks after vector delivery.49
 
 
 
To address the shortcoming of the standard paradigm for monitoring of liver health in DMD 
patients, glutamate dehydrogenase (GLDH) has been identified as a liver-specific biomarker 
of liver injury that is independent of muscle damage.50  In these studies, GLDH has been 
found to be as effective as ALT in diagnosing liver injury.  Thus, GLDH will be used as a 
sensitive biomarker of liver injury in this study and may be used to guide additional 
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immunomodulatory intervention, as well as to confirm potential cases meeting Hy’s law 
criteria based on elevations of bilirubin alone (in the context of elevated AST/ALT due to 
muscle damage). 
As with other gene therapy clinical studies, elevations in liver enzymes are not unexpected.  
In this study, all subjects will have received glucocorticoids for at least 6 months, with a 
stable daily regimen for at least 3 months prior to the Baseline visit, and will continue to 
receive elevated daily doses of glucocorticoids for at least 3 months post-infusion of 
investigational product before returning to their pre-study doses of glucocorticoids for at least 
the remainder of the first year post-infusion.  It is anticipated that the pre-existing steroid 
regimen along with the 3-month modified regimen may assist in controlling potential 
AAV-mediated liver injury.49  However, should liver injury be detected, the glucocorticoid 
doses may need to be increased further, or other immunomodulatory therapy initiated, in 
consultation with the assigned immunopharmacologic and/or hepatic experts. 
1.5.2. Immunogenicity to AAV and transgene
Humoral and cellular immune responses against both vector and the transgene may 
negatively impact safety and efficacy of gene therapy approaches and therefore need to be 
carefully monitored.51  Humoral responses against AAV frequently occur in the population in 
response to spontaneous infection, with the incidence increasing with age.  In fact, a single 
infusion with AAV leads to an effective induction of humoral immune responses.52  
Neutralizing antibodies (NAb) against the AAV capsids have been shown to negatively 
impact transduction.23  Depending on the assay used to measure NAb, the prevalence of NAb 
to AAV9 in the general population can range from 30-40%53 and in DMD patients 
pre-existing antibodies to AAV9 ranged from 10-20% depending on the assay cut-point.54  
Cellular immune response to transgene, specifically dystrophin, has been observed in clinical 
studies40 and also in non-clinical studies (Section 1.3.1).  In fact, a study by Flanigan 
(2013)55 showed that there are pre-existing T cell responses to dystrophin in DMD patients.  
The study demonstrated that increasing age correlated with an increased risk for the presence 
of anti-dystrophin T cell responses and that treatment with corticosteroid decreased that risk 
compared to no treatment, suggesting that steroid treatment may modulate T cell responses. 
For the reasons described above, no subjects with pre-existing NAb to AAV9 or pre-existing 
T cell responses to the transgene product as measured by Enzyme-Linked ImmunoSpot 
[ELISpot] above a certain threshold, as determined by the testing laboratories and sponsor, 
will initially be enrolled into this Phase 1b study. 
 In addition, systemically delivered AAV-based 
gene therapy is currently limited to single dose administration due to the development of 
NAb.  Thus, subjects participating in this Phase 1b study will likely be excluded from 
participating in future AAV-based studies or from receiving future re-administration of 
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Although it has not been described, either in previous dystrophin gene therapy clinical trials, 
or in pre-clinical models, a cellular immune response to newly and widely expressed 
dystrophin could theoretically induce local tissue damage related to the site of new protein 
expression, which would have the potential for clinical manifestation as a myositis or 
myocarditis.  Both will be difficult to monitor in the setting of DMD, given the degree of 
ongoing muscle and myocardial damage related to the disease but will require a low 
threshold for diagnostic consideration. 
A diagnosis of myositis might be considered in the event of evidence of increasing muscle 
pain or weakness associated with a rising creatine kinase (CK) or C-reactive protein (CRP).  
MRI and comparison to baseline scans may aid in the diagnosis.  Myocarditis may be 
considered in the event of increased or new cardiac symptoms, an increased cardiac 
troponin I (cTnI) and creatine kinase myocardial b fraction (CK-MB), CRP, or as evidenced 
on electrocardiogram (ECG) or cardiac MRI (or echocardiogram).  
 
 
 
 
 
 
 
 
 
Furthermore, the study will utilize an external data monitoring committee (E-DMC) to 
provide an objective assessment of safety, and which may include an expert in clinical 
immunopharmacology (eg, clinical immunologist, rheumatologist, transplant physician) for 
ad hoc consultation should the need arise (Section 9.6).
1.5.3. Other Risks
Possible risks related to the administration of the study drug and/or as a consequence of 
phlebotomy may include hematoma or bruising.  If a temporary peripherally inserted central 
catheter (PICC) is used to facilitate the collection of blood samples, possible risks may 
include infection at the site, systemic infection, blood clots, bleeding, and nerve injury.  
For the sirolimus cohort: possible risks associated with administration of sirolimus in a 
pediatric population may include risks listed in the prescribing information71 as well as 
additional risks identified by review of postmarketing pediatric off label use, provided in 
Appendix 1.
1.5.4. Other Safety Monitoring
Additional safety monitoring is described in Section 7.2.
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1.6. Other
Study C3391001 is the first gene transfer study with PF-06939926 being conducted in 
subjects with DMD.  The drug may demonstrate pharmacologic activity in subjects.  
PF-06939926 is a viral vector that may transfer mini-dystrophin into muscle (and other) 
tissues.  The gene may persist in the body for a long time; therefore, subjects will be 
followed for a total of 5 years post-infusion of PF-06939926.
Data from non-clinical animal testing support an acceptable risk profile for PF-06939926 in 
the current study and support a favorable benefit-risk profile in the indication of DMD.  
Authorities will be kept informed of any additional data (eg, results from clinical studies) 
which may affect the assessment of the benefit-risk profile for PF-06939926.
 
 
 
 
 
 
 
 
 
 
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2. STUDY OBJECTIVES AND ENDPOINTS
Primary Objective:
Primary Endpoints:

To determine the safety and 
tolerability of a single IV infusion 
of PF-06939926 in subjects with 
DMD at ascending doses.

Incidence of both dose-limiting and 
treatment-related adverse events 
(AEs), inclusive of infusion and 
injection site reactions, through 
1 year post-treatment.

Incidence, severity, and causal 
relationship of treatment-emergent 
AEs (TEAEs) through 1 year 
post-treatment.

Incidence and magnitude of 
abnormal laboratory findings 
through 1 year post-treatment.

Abnormal and clinically relevant 
changes in physical and 
neurological examinations, weight, 
vital signs, electrocardiogram 
(ECG), cardiac magnetic resonance 
imaging (MRI)- (or 
echocardiogram-) measured left 
ventricular ejection fraction 
(LVEF), Columbia Suicide 
Severity Rating Scale (C-SSRS) 
through 1 year post-treatment.

Secondary Objectives:

Secondary Endpoints:

To determine the amount and 
distribution of mini-dystrophin 
expression in the muscle of subjects 
with DMD following a single IV 
infusion of PF-06939926 at 
ascending doses.

To evaluate long term safety of a 
single IV infusion of PF-06939926 
in subjects with DMD at ascending 
doses.

Evidence of mini-dystrophin 
expression and transduction in 
muscle by immunohistochemistry 
(IHC) and Western Blot (WB) 
and/or LC-MS using muscle 
biopsies at 2 or 3 and 6 or 
12 months post-treatment.

Incidence, severity and causal 
relationship of TEAEs and 
clinically significant safety 
findings, as described for the 

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primary endpoints (above) through 
5 years post-treatment.
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3. STUDY DESIGN
3.1. Study Overview
This study is a multi-center, open–label, non-randomized, ascending dose, safety and 
tolerability study of a single IV infusion of PF-06939926.  There will be up to 22 subjects 
who will receive a single dose of PF-06939926 between 1E+14 vg/kg and 3E+14 vg/kg per 
the ITR-based method or 2E+14 vg/kg per the TG-titer method, as described in Section 1.4.1, 
with the option of de-escalating in the case of a suspected dose-limiting toxicity at this 
highest dose level.  Up to 19 subjects who receive PF-06939926 are expected to be 
ambulatory upon study entry, and the remaining subjects are expected to be non-ambulatory, 
depending on availability of investigational product.  The differences between these DMD 
sub-populations relate to age, weight, functional performance, and cardiac function at 
Screening, as described in Section 4.1 and Section 4.2.  Sites will be kept updated of study 
enrollment status to mitigate risk of over-enrollment of either sub-population.   
In order to mitigate unanticipated risks to subject safety, enrollment will be staggered within 
and between the two cohorts and will include a formal review by the E-DMC prior to dose 
progression and in the event of any possible safety signals (see Section 3.5).  Any and all 
changes to dose-level will be communicated to sites by formal letter, regardless of reason 
(eg, changes in the name only due to development of a more precise titer assay, escalation or 
de-escalation following E-DMC reviews, etc.).  Within each of the cohorts, the dosing 
interval between the first and second subjects will be at least 6 weeks.  If no safety concerns 
are identified 3 weeks after the second subject is infused, then dosing may proceed at Ŏ
2-3-week intervals.  Similarly, if no stopping or pause criteria (as described in Section 3.5) 
are met after dosing 6 consecutive subjects at a single dose level, then, with E-DMC 
agreement, dosing may proceed at that same dose level in ≥1-week intervals.  A visual 
description of the study design is provided in Figure 2.
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Figure 2.
Study Schematic
3.2. Planned Number of Subjects
Depending on availability of investigational product, up to 22 subjects, including up to 
19 ambulatory subjects and 3 non-ambulatory subjects, including those participating in the 
sirolimus cohort, are planned to participate in up to 5 centers in the United States (US).  
Subjects who are withdrawn for reasons other than safety may be replaced at the discretion of 
the sponsor.
It is anticipated that approximately 40% of the general population may have detectable NAb 
to AAV953 which would preclude participation in this trial (see Exclusion Criteria).  Thus, in 
consideration of this criterion and the other eligibility criteria, approximately 37 subjects may 
need to be screened in order to meet the overall enrollment target.  In light of this screen 
failure rate, efforts will be made to minimize subject burden by obtaining the NAb results 
prior to conducting the other Screening procedures, when feasible, while also balancing the 
timing of the Screening visits with the staggered enrollment.  Such efforts will require close 
communication between the site staff and sponsor study team.
*Dose-level determined by inverted terminal repeat (ITR)-titer based assay, but PF-06939926 3E+14 vg/kg 
using the ITR- based titer assay is approximately equivalent to PF-06939926 2E+14 vg/kg under the transgene 
(TG)-based titer assay.
^Number of biopsies may be reduced or eliminated for the non-ambulatory subjects as per sponsor discretion.

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3.3. Duration of Subject Participation
Willing and eligible subjects will participate in the trial for approximately 5.5 years, and 
visits will include the following:

Screening: approximately 2 days of assessments across 2-3 visits within an 
approximately 26-week period relative to the Baseline visit; 

Baseline: approximately 2 days of assessments across 1-2 visits within a 2-week 
period; 

Treatment: approximately 2 visits: 1) single administration of PF-06939926 followed 
by at least 24 hours of in-patient monitoring (ie Days 1 and 2), and 2) 2-week 
follow-up in which subjects will remain local to the investigational site, and complete 
1-day visits occurring on Days 4, 7, and 10 (±1 day) for blood sample collection and 
safety monitoring, as well as sample collection for local laboratory testing on 
Days 5-9, or longer, as clinically indicated;

1st Year Follow-up: approximately 1 to 3 days of assessments for 6 visits, as well as 
8 remote visits (eg, blood sample collection at subject’s home, virtual wellness 
check-ins that include AE assessments, activity monitoring), during the first 
12 months following the single administration of PF-06939926; 

Long-Term Follow-up: total of 4 annual, 2 or 3-day visits starting approximately 
2 years following the single administration of PF-06939936, as well as 4 remote visits 
(eg, blood sample collection in the subject’s home, virtual wellness check-ins) in 
between the 4 annual visits. 
3.4. Approximate Duration of Study
The entire study is estimated to complete in approximately 8 years, allowing for 
approximately 3 years of staggered enrollment and 5 years of follow-up.
The end of the study will be the last visit of the last subject for purposes of closing out sites, 
informing the institutional review board/ethics committee (IRB/EC), and ceasing to send 
Council for International Organizations of Medical Sciences (CIOMS) reports.
3.5. Dose Progression and Stopping Rules
As described above (Section 3.1), 2 cohorts are planned in this study.  The available results 
of the 2-month muscle biopsies of the enrolled subjects will be reviewed prior to dosing the 
4th subject in the low-dose cohort, and in either of the following cases, an ad hoc E-DMC 
review of the available cumulative safety data may be requested to assess whether escalation 
to the high-dose cohort may commence:
1. No measurable transgene (mini-dystrophin) noted in 2 of the first 3 enrolled subjects, 
or

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2. Level of transgene expression is regarded by the sponsor as inadequate to translate 
into functional benefit.
If adequate transgene expression is observed, dosing of the remaining subjects in the 
low-dose cohort will continue as planned, after which an E-DMC review of available 
cumulative safety data will occur.
In any circumstance, progression to the high-dose cohort will not proceed until the first dose 
level is deemed safe by the E-DMC, principal investigators and sponsor study team. 
If no transgene (mini-dystrophin) expression is observed in any of the 2-month biopsies from 
the low-dose cohort, then prior to dosing the 4th subject in the high-dose cohort, all available 
biopsies may be assessed.  If these samples are also negative for transgene (mini-dystrophin) 
expression, an ad hoc E-DMC review of the available cumulative safety data may be 
requested to determine whether the study should be terminated.
For both cohorts and at any dose level of PF-06939926, if one of the following safety issues 
occurs, further enrollment will be halted until the E-DMC reviews data for the subjects with 
the clinical events that prompted the review and makes recommendations as to next steps: 

Any potentially treatment-related serious adverse event (SAE);

Similar clinically significant safety findings in ≥50% of subjects at a given dose 
level, indicating dose-limiting intolerance;

Repeated alkaline phosphatase or total bilirubin >2 × the upper limit of normal 
(ULN);

Any set of laboratory results meeting Hy’s Law (see Section 8.4.2 for Hy’s Law 
criteria);

Clinical diagnosis of myositis or myocarditis;

Other findings that, at the discretion of the sponsor study team, investigator and/or 
E-DMC, indicate that dose escalation should be halted or that dose de-escalation 
would be appropriate.
Additional information on the E-DMC can be found in Section 9.6.
4. SUBJECT ELIGIBILITY CRITERIA
This study can fulfill its objectives only if appropriate subjects are enrolled.  The following 
eligibility criteria are designed to select subjects for whom participation in the study is 
considered appropriate.  All relevant medical and nonmedical conditions should be taken into 
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Subject eligibility should be reviewed and documented by an appropriate member of the 
investigator’s study team before subjects are included in the study.
4.1. Inclusion Criteria
Subjects must meet all of the following inclusion criteria to be eligible for enrollment into the 
study:
1. Evidence of a personally signed and dated informed consent and/or assent (where 
appropriate) document indicating that the subject or a legally acceptable 
representative/parent(s)/legal guardian has been informed of all pertinent aspects of 
the study (see Section 12.3 for additional information regarding the consenting 
process). 
2. Willingness and ability by subject, as well as parent(s)/legal guardian(s) when 
appropriate, to comply with scheduled visits, treatment plan, laboratory tests, and all 
other required study procedures.
3. Males, who are aged as follows based on Ambulatory Status (ie, ability to walk 10 
meters unassisted):

FOR AMBULATORY SUBJECTS: 4 to 12 years, inclusive;

FOR NON-AMBULATORY SUBJECTS: No age restrictions so long as loss of 
ambulation occurs prior to the subject’s 17th birthday. 
4. Body weight, as follows: 

FOR AMBULATORY SUBJECTS: ≥15 to ≤50 kg;

FOR NON-AMBULATORY SUBJECTS: Up to 75 kg, but enrollment will be 
controlled by steady increases in body weight to enable cautious accumulation of 
safety information across the broad weight range.  Unless the sponsor formally 
informs the site staff otherwise, enrollment will occur such that a minimum of 
2 subjects in each of the following weight ranges will be dosed in the following 
order: 

>35 to ≤50 kg;

>50 to ≤60 kg; 

>60 to ≤75 kg.
5. Diagnosis of Duchenne muscular dystrophy (DMD) confirmed by the subject's 
medical history and by genetic testing prior to screening.  Note that the latter may 
require confirmation by repeat testing by an appropriately regulated, central 
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6. Receipt of glucocorticoids for ≥6 months and a stable daily dose (≥0.25 mg/kg/day
prednisone, prednisolone, or deflazacort) for at least 3 months prior to the Baseline 
visit.
7. Functional performance as follows, based on Ambulatory Status (ie, ability to walk 
10 meters unassisted):

FOR AMBULATORY SUBJECTS, defined as those able to walk 10 meters 
unassisted as part of Ambulatory Status, AND with 

Ability to rise from floor within seven (7) seconds (as part of NSAA);

FOR NON-AMBULATORY SUBJECTS, defined as those unable to walk 
10 meters unassisted, AND with:

Adequate respiratory function as evidenced by percent predicted forced vital 
capacity (%pFVC) >40% (as part of pulmonary function), AND

Adequate upper limb function as evidence by the PUL, version 2.0, Entry 
Item A score of ≥3.
NOTE: Although a window of up to 26 weeks (182 days) between Screening and Baseline is 
permitted, if time between Screening and the planned Baseline visit exceeds 12 weeks 
(84 days), then these functional assessments should be repeated and eligibility (re)confirmed 
prior to enrolling the subject.
8. Ability to tolerate magnetic resonance imaging (MRI) without sedation and with no 
contraindications to these procedures.
9. Ability to tolerate muscle biopsies under anesthesia with no contraindications to these 
procedures.
4.2. Exclusion Criteria
Subjects with any of the following characteristics/conditions will not be included in the study 
(ie, will not receive PF-06939926):
1. Receipt of a live attenuated vaccination within 3 months prior to receipt of 
PF-06939926 or exposure to an influenza (or other inactivated) vaccination or 
systemic antiviral and/or interferon therapy within 30 days prior to receipt of 
PF-06939926.
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3. The following genetic abnormalities in the dystrophin gene as confirmed by the 
investigator based on the review of the DMD genetic testing: 
a.
Any mutation (exon deletion, exon duplication, insertion, or point 
mutation) affecting any exon between exon 9 and exon 13, inclusive; OR 
b. A deletion that affects both exon 29 and exon 30.
4. Prior treatment with gene therapy, defined as any therapy introducing exogenous 
DNA or intended to permanently alter the endogenous DNA. Gene therapy (other 
than study drug) will be prohibited for the duration of the study.
5. Exposure within 6 months prior to Screening (Visit 1) to any treatment designed to 
increase dystrophin expression (including, but not limited to exon-skipping agents 
and nonsense read-through). These treatments will also be prohibited during the 
period between Screening (Visit 1) and Day 1 (Visit 3) and for the first year of the 
study. 
6. Participation in other studies involving investigational drug(s) within 30 days or 
within 5 half-lives, whichever is longer, prior to the Baseline visit.
7. Known hypersensitivity to any of the components of the study drug or solution for 
infusion, such as hypersensitivity to albumin or a diagnosis of (or symptoms 
suggestive of) hereditary fructose intolerance (HFI).  Symptoms suggestive of HFI 
include nausea, vomiting, bloating, stomach cramps, or diarrhea following the 
ingestion of sweet foods or drinks, or a pattern of avoiding sweet foods or drinks.
8. NAb against AAV9 above threshold set by testing laboratory at Screening (and 
Baseline if required See Schedule of Activities, footnote i). 
9. Abnormality in hematology or chemistry profiles at screening: 
a.
Absolute neutrophil count (ANC) <1000 cells/mm3;
b. Cystatin C >1.2 x ULN;
c.
Platelets <150 × 10
3/µL;
d. Positive hepatitis A virus (anti-HAV) immunoglobulin M (IgM), hepatitis B 
surface antigen (HBsAg), and/or hepatitis C antibody (HCVAb); 
e.
Serum markers indicating possible autoimmune-mediated hepatitis: 
1.Antinuclear antibody (ANA) titer >1:160;
2.Total IgG >2 x ULN;

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f.
Markers of hepatic inflammation or overt or occult cirrhosis as evidenced by 
one or more of the following:
i. Total bilirubin >1.5 x ULN and direct bilirubin ≥0.5 mg/dL;
3.GGT >1.5 x ULN;
4.PT > ULN; prolonged INR >ULN;
5.GLDH >2 x ULN;
NOTE: Although a window of up to 26 weeks (182 days) between Screening and 
Baseline is permitted, if time between Screening labs and the planned Baseline visit is to 
exceed 12 weeks (84 days), then all Screening labs except for DMD genetic testing 
should be repeated and eligibility (re)confirmed prior to enrolling the subject.
10. Compromised cardiac function as indicated by a left ventricular ejection fraction 
(LVEF) on cardiac MRI obtained during or within 3 months prior to Screening, as 
evaluated by a central imaging vendor, and based on ambulatory status as follows: 

FOR AMBULATORY SUBJECTS: LVEF of <55%; 

FOR NON-AMBULATORY SUBJECTS: LVEF of <35%. 
NOTE: If the cardiac MRI is unable to be read (eg, due to an inability by a younger 
subject to remain still during the scan), then echocardiogram may be performed and read 
locally. 
11. Any injury which may impact functional testing.  Previous injuries must be fully 
healed prior to consenting.  For ambulatory subjects, prior lower limb fractures must 
be fully healed and at least 3 months from injury date.
12. Clinically significant infection within 30 days prior to study drug administration, as 
determined by the investigator. 
13. Refusal or inability to use acceptable forms of birth control for the duration of the 
study and through completion of final study visit (Section 4.5.2).
14. Presence or history of other musculoskeletal or neurological disease in addition to 
DMD.
15. Evidence or history of clinically significant hematological, renal, endocrine, 
pulmonary, gastrointestinal, cardiovascular, hepatic, cancer, autoimmune or allergic 
disease (including drug allergies), but excluding untreated, asymptomatic, seasonal 
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16. Other acute or chronic medical or psychiatric condition including recent (within the 
past year) or active suicidal ideation or behavior (within the past 6 months) or 
laboratory abnormality that may increase the risk associated with study participation 
or investigational product administration or may interfere with the interpretation of 
study results and, in the judgment of the investigator, would make the subject 
inappropriate for entry into this study.
17. Investigator site staff members directly involved in the conduct of the study and their 
family members, site staff members otherwise supervised by the investigator, or 
subjects who are Pfizer employees, including their family members, directly involved 
in the conduct of the study.
NOTE: Screening results considered by the investigator to be transient and inconsistent with 
the subject’s clinical condition may be repeated once during the Screening period for 
confirmation of eligibility.  The reason for repeating the assessment should be documented.
4.3. Caregiver(s)
The parent(s) or legal guardian(s) of the subject will actively participate as caregiver in this 
study.  As caregiver(s), the parent(s) or legal guardian(s) will not only provide informed 
consent for those subjects who are <18 years of age (or as appropriate, per Section 12.3), but 
will also actively participate in the study at least for subjects who are minors, including 
attendance at study visits, exchanges during wellness check-ins, and completion of 
patient-reported questionnaires on behalf of the subject as well as himself and herself.  With 
consent, the caregiver’s demographic information may be collected.  The caregiver(s) will 
also communicate observed safety information to the investigator or designee as appropriate.
For subjects who are minors,  a caregiver(s) must meet all of the following criteria for the 
subject to be eligible for enrollment in the study: 

Aged ≥18 years of age and has demonstrated responsibility as a legal caregiver(s) 
through monitoring the subject and reporting any observed AEs;

Willingness and ability to provide written informed consent on behalf of the subject;

Ability to accompany the subject to the clinic visits and complete certain assessments 
on behalf of the subject, as well as for themselves, if willing;

Ability to follow instructions.
4.4. Re-screening
Subjects who are screened but ultimately discontinued prior to receipt of PF-06939926 for 
reasons other than a confirmed, non-transient failure to meet all eligibility criteria 
(eg, enrollment pause due to regulatory or safety review, operational issues causing 
significant delays, etc) may be allowed to re-screen during the study while enrollment 
remains open.  In this case, the subject number assigned at the initial screening will be 
documented as a screen failure the subject would be issued a new subject number for the 

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re-screen.  Re-screened subjects will re-consent, and screening assessments will need to be 
repeated, as described in Section 6.1.
4.5. Lifestyle Requirements 
4.5.1. Activity
Subjects should be instructed to continue with routine physical therapy including stretching 
or use of orthoses to prevent or minimize contractures or muscle deformities.
Subjects will be instructed to maintain normal activity levels and avoid activities that are not 
part of their normal daily routine within 24 hours of study visits where imaging or functional 
assessments will be performed. 
As this study involves a viral vector, it is suggested that subjects and those around them be 
reminded to practice good general hygiene for the first 1-2 months after receiving 
PF-06939926, such as the following: (1) thoroughly washing hands with soap after using the 
bathroom, before preparing or touching food, or after blowing one’s nose, coughing, 
sneezing, etc.; (2) avoiding contact with persons who might be sick; and (3) not sharing 
glasses, dishes, or utensils with other individuals.
In addition, for the first month following administration of PF-06939926, it is suggested that 
the caregivers assist the subjects with monitoring fluid intake and output.  Specifically, the 
recommendations are that subjects consume at least 1 liter of water per day and pass urine at 
least 3 times during each 24-hour period through the first month, or longer if deemed 
clinically necessary.  If fluid intake and output are observed to be less than these thresholds, 
then subjects (and/or caregivers) should be instructed to promptly contact the site for a 
possible unscheduled visit and/or biospecimen collection.
4.5.2. Contraception
All subjects who are, in the opinion of the investigator, able to father children and sexually 
active and at risk for pregnancy with their partner(s) must agree to use a highly effective 
method of contraception consistently and correctly for the duration of the study, including
long-term follow-up.  The investigator or his or her designee, in consultation with the subject 
and/or the subject’s legal caregiver (depending on the subject’s age and appropriateness of 
this sensitive topic), will confirm that the subject has selected an appropriate method of 
contraception for the individual and partner from the permitted list of contraception methods 
(see below) and will confirm that the subject has been instructed in its consistent and correct 
use.  Throughout the study, the investigator or designee will inform the subject and/or legal 
caregiver of the need to use highly effective contraception consistently and correctly and 
document the conversation and the subject’s affirmation in the subject’s chart (subjects need 
to affirm their consistent and correct use of at least 1 of the selected methods of 
contraception).  In addition, the investigator or designee will instruct the subject and/or legal 
caregiver to call immediately if the selected contraception method is discontinued or if 
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Highly effective methods of contraception are those that, alone or in combination, result in a 
failure rate of less than 1% per year when used consistently and correctly (ie, perfect use) and 
include the following:
1. Male condom used WITH a separate spermicide product (ie, foam, gel, film, 
cream, or suppository); 
2. Male sterilization with absence of sperm in the post-vasectomy ejaculate.
NOTE: Sexual abstinence, defined as completely and persistently refraining from all 
heterosexual intercourse (including during the entire period of risk associated with the study 
treatments) may obviate the need for contraception ONLY if this is the preferred and usual 
lifestyle of the subject.
4.6. Sponsor’s Qualified Medical Personnel
The contact information for the sponsor's appropriately qualified medical personnel for the 
study is documented in the study contact list located in the supporting sponsor study team 
electronic storage site and/or study portal.  
To facilitate access to appropriately qualified medical personnel on study-related medical 
questions or problems, subjects are provided with a contact card.  The contact card contains, 
at a minimum, protocol and investigational product identifiers, subject study numbers, 
contact information for the investigator site, and contact details for a contact center in the 
event that the investigator site staff cannot be reached to provide advice on a medical 
question or problem originating from another healthcare professional not involved in the 
subject’s participation in the study.  The contact number can also be used by investigator 
staff if they are seeking advice on medical questions or problems; however, it should be used 
only in the event that the established communication pathways between the investigator site 
and the sponsor study team are not available.  It is therefore intended to augment, but not 
replace, the established communication pathways between the investigator site and the 
sponsor study team for advice on medical questions or problems that may arise during the 
study.  The contact number is not intended for use by the subject directly, and if a subject 
calls that number, he or she will be directed back to the investigator site.
5. STUDY TREATMENTS
For the purposes of this study, and per International Conference on Harmonisation (ICH) 
guidelines, investigational product is defined as a pharmaceutical form of an active 
ingredient or placebo being tested or used as a reference/comparator in a clinical trial, 
including a product with a marketing authorization when used or assembled (formulated or 
packaged) in a way different from the approved form, or when used for an unapproved 
indication, or when used to gain further information about an approved use (ICH E6 1.33). 
For this study, the investigational product is PF-06939926.  
Refer to the Investigational Product Manual and the Administration Card for details 
regarding the preparation and administration of this investigational product.

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Subjects will be treated with a single IV infusion of PF-06939926.  Please refer to 
Investigational Product Manual for complete information on storage, stability, preparation 
and administration of PF-06939926.
This study is an open-label, non-randomized study in which subjects will receive a single IV 
infusion of an ascending dose of PF-06939926.  Subjects in the low-dose cohort will receive 
a single infusion containing 1E+14 vg/kg, and subjects in the high-dose cohort are planned to 
receive a single infusion containing 3E+14 vg/kg per ITR-based titer method.  However, 
should a dose-limiting safety event occur at this highest dose level, subsequent subjects may 
be administered 2E+14 vg/kg or lower per ITR-based titer method.  The dose will be 
calculated based on the subject weight, which will be obtained at the Baseline visit (see 
Section 5.3.1). 
To mitigate risk of an immune response and drug-induced liver injury, as described in 
Section 1.5, subjects will temporarily replace their daily glucocorticoid regimen as follows: 
1. Between 1 and 4 hours prior to infusion of PF-06939926: receipt of single dose of 
IV methylprednisolone ≥2 mg/kg;
2. For first 2 weeks post-infusion of PF-06939926: switch of daily glucocorticoid 
dose to ≥2 mg/kg/day of oral prednisone or prednisolone; 
3. For Weeks 3 and 4 post-infusion of PF-06939926: reduction of daily 
glucocorticoid dose to ≥1.5 mg/kg/day of oral prednisone or prednisolone; 
4. For Weeks 5, 6, 7, and 8 post-infusion: reduction of oral prednisone or 
prednisolone dose to a minimum of >1.0 mg/kg/day; 
5. For Weeks 9, 10, 11, and 12 post-infusion: reduction of oral prednisone or 
prednisolone dose to a minimum of 0.75 mg/kg/day;
6. After Week 12 post-infusion: reduction of oral prednisone or prednisolone dose to 
a minimum of 0.5 mg/kg/day or return to pre-study daily doses of prednisone or 
prednisolone, whichever dose is higher.
These doses will be calculated within approximately 10% of the subject’s body weight. 
Provided that no signals of a latent immune response are present following these 
3 months of descending dose levels of prednisone or prednisolone, subjects may then 
return to their pre-study dose levels of daily glucocorticoids (eg, prednisone, 
prednisolone, or deflazacort) for at least the remainder of the first year following receipt 
of PF-06939926. 
5.1. Allocation to Treatment
The investigator’s knowledge of the treatment should not influence the decision to enroll a 
particular subject or affect the order in which subjects are enrolled. 

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Allocation of subjects for treatment will be performed by the sponsor’s study management 
team.  An interactive response technology (IRT) system (interactive Web-based response 
[IRT] will be used for subject screening and enrollment.  The site personnel (study 
coordinator or specified designee) will be required to enter or select information including 
but not limited to the user’s identification (ID) and password, the protocol number, and the 
subject-specific identification number (SSID), the subject’s weight collected at Baseline 
(Section 5.3.1) and subject’s date of birth.  The site personnel will then be provided with an 
enrollment number via the IRT system.  The IRT system will provide a confirmation report 
containing the subject number, and enrollment number.  The confirmation report must be 
retained by the dispenser in the site files. 
Subjects will be allocated to the open dose cohort according to their enrollment number.  
Once subject screening and enrollment numbers have been assigned, they cannot be 
reassigned.
The study-specific IRT reference manual will provide the contact information and further 
details on the use of the IRT system. 
5.2. Subject Compliance
Investigational product will be administered by the appropriately designated study staff at the 
investigator site.
5.3. Investigational Product Supplies
5.3.1. Dosage Form(s) and Packaging
The amount of study drug shipped to site will be based on subject’s Baseline body weight 
and the lot-specific concentration of PF-06939926.  A shipment order will be raised once the 
subject is registered (ie, enrolled) following confirmation of eligibility.  Thus, it is highly 
recommended that all subject-level details, especially body weight, are confirmed by two 
(2) site personnel prior to enrolling the subject, so as to ensure that the appropriate amount of 
study drug is sent to the site for dosing.  Guidance for collecting the most accurate weight is 
provided in Section 7.2.4.2.  As a minimum of 2 weeks (14 calendar days) is required for 
shipment of study drug, enrollment should occur promptly following the measurement of the 
subject’s weight at Baseline. 
The dose will be prepared by the site pharmacist following the instructions in the 
Investigational Product Manual.
PF-06939926 will be supplied as a sterile, frozen solution requiring thawing and further 
dilution for IV administration.  The drug product is supplied in a clear closed vial 
configuration with stopper and a cap in place.  Each vial contains a 5 mL nominal fill volume 
of PF-06939926.  Each lot of PF-06939926 will have a lot-specific titer concentration.
Details of the drug product packaging, accompanying shipment documentation and drug 
product preparation are provided in the Investigational Product Manual. 

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All ancillary supplies used to prepare and administer doses will be provided by the clinical 
site conducting the study unless otherwise agreed by the sponsor.
5.3.2. Preparation and Dispensing
See the Investigational Product Manual for instructions on how to prepare the investigational 
product for administration.  Investigational product should be prepared and administered by 
appropriately qualified and experienced members of the study staff (eg, physician, nurse and 
pharmacist as allowed by local, state, and institutional guidance).  The subject’s weight from 
Baseline will be used for calculating the dose.  All dosage calculations, as well as dose 
preparation, must be performed and checked by a minimum of two (2) qualified clinical site 
personnel.
PF-06939926 vials are single use only.
Only qualified personnel who are familiar with procedures that minimize undue exposure to 
themselves and to the environment should undertake the preparation, handling, and safe 
disposal of gene therapy, specifically AAV-vector based agents. Additional details regarding 
inadvertent exposure and instructions on spill cleanup procedures are outlined in the 
“Investigational Product Manual”.
5.4. Investigational Product Administration
Delivery of premedication with IV methylprednisolone ≥2 mg/kg between 1 and 4 hours 
prior to infusion is required for all subjects in lieu of daily oral glucocorticoid.
Subjects will be admitted to the investigational site to receive a single intravenous infusion of 
PF-06939926 delivered over approximately 2 to 4 hours (+30 minutes) at Visit 3 in 
accordance with the Schedule of Activities and will be monitored for at least 24 hours 
following completion of the infusion. 
The appropriate amount of PF-06939926, based on the actual concentration for the lot, the 
subject’s Baseline body weight and the dose level, will be prepared and administered in a 
solution of approximately 250 mL to 500 mL containing a small amount of human serum 
albumin as detailed in the Investigational Product Manual.  Appropriate medication and other 
supportive measures for management of an acute hypersensitivity reaction should be 
available in accordance with local guidelines for standard gene therapy practices.
Preparation and administration of investigational products should be performed by 
appropriately qualified, Good Clinical Practice (GCP)-trained, and preferably gene 
therapy-experienced members of the study staff (eg, physician, nurse, physician’s assistant, 
nurse practitioner, pharmacist, or medical assistant) as allowed by local, state, and 
institutional guidance. 
Should subjects experience any infusion site reaction during the IV infusion period, the 
administration should be interrupted, and supportive care should be provided according to the 
investigator’s standard of care practice (eg, treatment with an antihistamine and/or 
glucocorticoid, etc).  The administration can be restarted based on the medical judgement of 

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the investigator. It is recommended that the investigator assess the infusion reaction and 
establish new IV access if needed, as every reasonable effort should be made to complete the 
entirety of the dose.  The study drug solution has 8 hour stability at room temperature from 
the start of dose preparation (initial study drug vial puncture).  If there is an interruption to 
the infusion, the 8 hour in-use period cannot be extended, and every effort should be made to 
resume and complete the administration within this period. The time at which the infusion 
was paused, the volume infused prior to pausing the infusion, and the time at which the 
infusion resumes should all be noted in source documentation by those involved in study 
drug administration in addition to documentation required at end of infusion.
Investigational product administration details will be recorded on the case report form (CRF) 
within the clinical trial database.
5.5. Investigational Product Storage 
The investigator or an approved representative, eg, pharmacist, will ensure that all 
investigational products are stored in a secured area with controlled access under required 
storage conditions and in accordance with applicable regulatory requirements for gene 
therapy.
Investigational products should be stored in their original containers and in accordance with 
the labels. 
PF-06939926 sterile, cryogenic vials must be stored frozen at -60 to -90°C.
The Investigational Product Manual will contain instructions on thawing the sterile, 
cryogenic vials and for storage conditions of the product once thawed and/or diluted for 
administration.
Any storage conditions stated in the SRSD (eg, IB) will be superseded by the storage 
conditions stated on the product label.
Site systems must be capable of measuring and documenting (for example, via a log), at a 
minimum, daily minimum and maximum temperatures for all site storage locations 
(as applicable, including frozen, refrigerated, and/or room-temperature products).  This 
should be captured from the time of investigational product receipt throughout the study.  
Even for continuous-monitoring systems, a log or site procedure that ensures active 
evaluation for excursions should be available.  The intent is to ensure that the minimum and 
maximum temperature is checked each business day to confirm that no excursion occurred 
since the last evaluation and to provide the site with the capability to store or view the 
minimum/maximum temperature for all non-working days upon return to normal operations.  
The operation of the temperature monitoring device and storage unit (ie, freezer) should be 
regularly inspected to ensure they are maintained in working order. 
Any excursions from the product label storage conditions should be reported to Pfizer upon 
discovery.  The site should actively pursue options for returning the product to the storage 

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conditions described in the labeling, as soon as possible.  Deviations from the storage 
requirements, including any actions taken, must be documented and reported to Pfizer. 
Once an excursion is identified, the investigational product must be quarantined and not used 
until Pfizer provides permission to use the investigational product.  It will not be considered a 
protocol deviation if Pfizer approves the use of the investigational product after the 
temperature excursion.  Use of the investigational product prior to Pfizer approval will be 
considered a protocol deviation.  Specific details regarding information the site should report 
for each excursion will be provided to the site.
5.6. Investigational Product Accountability 
The investigator site must maintain adequate records documenting the receipt, use, loss, or 
other disposition of the investigational product supplies.  All investigational products will be 
accounted for using a drug accountability form/record. 
5.6.1. Destruction of Investigational Product Supplies 
The sponsor or designee will provide guidance on the destruction of unused investigational 
product (eg, at the site).  The investigator must ensure that the materials are destroyed in 
compliance with applicable environmental regulations, institutional policy, and any special 
instructions provided by Pfizer, and all destruction must be adequately documented.
5.7. Concomitant Treatment(s)

Subjects will abstain from all prohibited concomitant medications/treatments, except 
if required for treatment of AEs;

All concomitant medications taken during the study will be recorded with the 
indication and start and stop dates of administration.  All subjects will be questioned 
about concomitant medications at each visit, including compliance with the required 
daily glucocorticoid regimen through at least the first year of follow-up;

Medications taken within 28 days prior to Day 1 will be documented as prior 
medication.  Medications taken from the time of Day 1 will be documented as 
concomitant medications.
5.7.1. Permitted Therapies

Prior to enrollment, subjects will be required to have received glucocorticoids 
(eg, deflazacort, prednisolone, or prednisone) for at least 6 months and with no 
significant changes (>0.2 mg/kg) in a daily dose regimen for at least 3 months prior to 
the Baseline visit.  The daily dose levels of the glucocorticoids should remain the 
same throughout the first year of follow-up with the exception of the following:
1. Planned temporary increases during the first few months following administration 
of study drug (Section 5);
2. Increases due to a potential drug toxicities (Section 5.8);

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3. Slight adjustments due to changes in weight (ie, <0.2 mg/kg). 

Subjects will also receive anesthesia according to the site standard of care for the 
muscle biopsies obtained in this study;

Subjects who have no contraindications and who have not previously received a 
MenACWY vaccination; or whose last vaccination at the time of the Screening visit 
(Visit 1) is outside the time period of active coverage specified by the vaccine 
manufacturermust receive at least 1 dose of MenACWY vaccine as early as possible 
in the Screening Period and not later than 30 days prior to receiving PF-06939926 and 
may receive prophylactic antibiotics in the event that the eculizumab is required to 
treat an immune response to PF-06939926, as described in Section 5.8;

Subjects must receive MenB vaccination if indicated by national vaccination 
guidelines no later than 30 days prior to receiving PF-06939926;

Subjects will be permitted to receive ACE (angiotensin-converting enzyme)
inhibitors, blockers, ARBs (angiotensin II receptor blockers) or aldosterone 
blocker/thiazide diuretics; 

Supplements such as vitamin D, coenzyme Q10, carnitine, amino acids (glutamine, 
arginine), anti-inflammatory/anti-oxidants (eg, fish oil, vitamin E, green-tea extract) 
are permitted; 

Bisphosphonates are permitted;

With the exception of any prohibited therapies (see next section), other medications 
may be deemed necessary by the investigator either to treat or prevent adverse events
that may be related to PF-06939926.  Examples of these may include but are not 
limited to antiemetics or antihistamines for anticipated or observed nausea and 
vomiting events, an increase in dose of glucocorticoids or addition of other 
immunosuppressants or complement inhibitors for anticipated or observed events 
associated with complement activation, as described in the IB.
5.7.2. Prohibited Therapies
The following are prohibited from the time of signing the informed consent through the final 
study visit:

Immunosuppressant agents, (other than glucocorticoids) unless administered in 
response to or to mitigate risk of immunologic reaction;

Other investigational therapies, including idebenone and tamoxifen;

Anti-myostatin, utrophin modifiers, and other gene therapy agents;

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•
Antiviral therapy, unless administered to treat an acute viral infection (eg, COVID-
19);
•
Interferon therapy, unless administered to treat an acute viral infection and used at 
least 2 months after administration of PF-06939926;
•
Sedation for imaging assessments.  
The following are prohibited during the period between Screening (Visit 1) and Day 1 
(Visit 3) and for the first 3 months following administration of PF-06939926:
•
Receipt of any required live attenuated vaccine(s);
•
Receipt of an influenza (or other inactivated) vaccine(s);
•
Receipt of an mRNA, or DNA-based, or non-replicating viral vector vaccine (eg, 
against SARS-CoV2).
The following are prohibited during the period between Screening (Visit 1) and Day1 
(Visit 3) and for the first year of the study:
•
Any treatment designed to increase dystrophin expression, (including, but not limited 
to exon-skipping agents and non-sense read through).
5.8. Rescue Medication
Should subjects experience an infusion site reaction during the IV infusion period, the 
treatment administration should be paused for the subject and supportive care should be 
provided according to the investigator’s standard practice (eg, treatment with an 
antihistamine). 
It is anticipated that the pre-study steroid regimen along with the 3-month post-dose 
glucocorticoid regimen (Section 5) may assist in controlling potential AAV-mediated liver 
injury in humans.49  However, should liver enzymes (ie, GLDH and bilirubin, Section 1.5.1) 
become elevated during the study, the glucocorticoid doses may need to be further increased 
or other immunomodulatory treatment added in ad hoc consultation with the assigned 
immunopharmacologic and/or hepatic experts.
 However, because the use of eculizumab increases the risk of contracting 
serious meningococcal infections, it is required that subjects not previously vaccinated 
receive at least 1 dose of meningococcal vaccination(s) at least 30 days prior to 
administration of PF-06939926 (ie, Baseline visit).  Alternatively (eg, in the case of allergy), 
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prophylactic antibiotics for meningococcus should be provided simultaneously with 
eculizumab, if administered.  In addition, the planned glucocorticoid doses may be increased 
and/or other immunosuppressants may be administered to treat or prevent an adverse immune 
reaction, such as those described above.  
Subjects who experience an event compatible with aHUS may be screened for a genetic 
predisposition to aHUS, as determined by the investigator in consultation with the sponsor to 
increase the understanding of the risk of developing aHUS (see Table 1).
6. STUDY PROCEDURES BY VISIT 
Every attempt should be made to schedule the visits on the day specified in the Schedule of 
Activities.  If possible, in order to provide optimal testing conditions and consistency in 
endpoint measurements, functional assessments and imaging would be best performed on 
two separate days within the visit window and at approximately the same time of day in the 
order described below. 
The visit windows are described below. 
6.1. Visit 1 (Screening): Days -196 to -17
This visit will be conducted over a minimum of 2 days to separate the days when the MRI of 
thigh and upper limb and functional assessments are conducted.  Sites may choose to extend 
this beyond 2 days to accommodate the logistics of completing all testing.  It is highly
recommended that the blood draw for immunogenicity testing be taken at the beginning of 
the Screening period due to the processing time for these assays.
During Screening, subjects and caregiver(s) will be assessed for study eligibility.  All 
Screening assessments must be completed and reviewed for subject eligibility before the 
subject is enrolled into the study.  Screening tests with results considered by the investigator 
to be transient and inconsistent with the subject’s clinical condition may be repeated once 
during the Screening period for confirmation of eligibility.  Imaging-based examinations for 
Screening must be reviewed for quality by the central imaging vendor before the subject is 
enrolled to assure an adequate baseline image has been acquired.  If the image is determined 
to be of poor quality, it may be repeated.  The visit window (Day -196 to -17) for screening is 
to allow for the analysis of laboratory testing, assurance of imaging quality and to provide 
multiple days to perform the assessments in the order described below.  However, certain 
Screening assessments, namely laboratory tests, functional assessments, thigh and upper limb 
MRI, would need to be repeated prior to enrollment should the time between these and the 
planned Baseline visit exceed 12 weeks (84 days), as described in Section 4.2.
If a subject is withdrawn from the study prior to receiving PF-06939926, but wishes to be 
re-screened and meets the criteria described in Section 4.4, this subject must be re-consented.  
In addition, all Screening assessments must be repeated with the exception of genetic testing 
to confirm DMD diagnosis, as well as cardiac imaging, the latter of which would only be 
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Assessments to be made for the Screening Visit include:
•
Informed Consent/Assent: Prior to initiation of any screening assessments the subject 
(if age of majority, as per Section 12.3) or subject’s parent(s) or legal guardian(s) must 
sign the informed consent document (ICD).  If a minor, the subject will be required to 
provide assent in compliance with local regulations and IRB/EC requirements;
•
Demographics: Information such as date of birth, race, ethnicity, and gender will be 
collected;
•
Medical History: Medical history will include confirmation by genetic testing of the 
diagnosis of DMD as reported from an appropriate regulated laboratory using a 
clinically-validated genetic test.  Results must confirm the presence of a mutation in the 
dystrophin gene(s) which is clinically consistent with the diagnosis of DMD.  The 
mutation type will be reported.  Medical history will also be reviewed for any significant 
medical histories and concurrent illnesses that required or are requiring specialist 
consultation or treatment;
•
Medication History: Complete history will include all prescription or nonprescription 
drugs, and dietary and herbal supplements taken within 28 days prior to the planned first 
dose.  The history of glucocorticoid use for at least 6 months with 3 months on a stable, 
daily dose prior to the Baseline visit will be collected to confirm eligibility; 
•
Inclusion/Exclusion Criteria: Subjects will be assessed against inclusion and exclusion 
criteria;
•
Physical Examination and Neurological Examination;
•
Height and Weight for determination of eligibility (ie, weight) and should be measured 
in morning, when feasible;  
•
Vital Signs: Blood pressure, pulse rate, and respiratory rate, and, if clinically indicated, 
body temperature;
•
Triplicate 12-lead ECG;
•
Clinical laboratory assessments:
•
Blood samples:
•
Confirmation of genetic testing of the diagnosis of DMD to be collected as early 
as possible in the screening period after informed consent;
 
 
 
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•
Clinical safety, including hematology, chemistry and other labs as described in 
Table 1.  
•
Anti-HAV IgM, HBsAg, HCVAb, ANA titer, total IgG;
 
 
 
NOTE: If time between Screening labs and the planned Baseline visit is to exceed 
12 weeks (84 days), then all Screening labs except for DMD genetic testing should be 
repeated and eligibility (re)confirmed prior to enrolling the subject.
•
Imaging Assessments: NOTE: cardiac MRI should be performed after the thigh and 
upper limb MRI exams or conducted on different days:
•
Thigh and upper limb MRI (to be performed before functional assessments if done on 
the same day). 
NOTE: If time between Screening thigh and upper limb MRI and the planned 
Baseline visit is to exceed 12 weeks (84 days), then these should be repeated prior to 
enrollment.
•
Cardiac MRI.
•
If cardiac MRI were obtained within 3 months prior to the Screening visit, and, 
per the site, sponsor, and central imaging lab, the images can be submitted for 
central reading and are deemed adequate for confirming eligibility, then another 
cardiac MRI may not be required for this visit.
•
If the initial cardiac MRI cannot be analyzed (eg, due to poor imaging quality), a 
repeat will be required to confirm eligibility, which may take an additional 
1-2 weeks.  However, if quality images are unable to be obtained due to a 
limitation by the subject (eg, young subject unable to remain still during the scan), 
then echocardiogram may be permitted and read locally.
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
Functional assessments: 

FOR AMBULATORY SUBJECTS: Ambulatory status and NSAA for confirmation 
of eligibility;

FOR NON-AMBULATORY SUBJECTS: Ambulatory status (even if only form is 
completed because subject is unable to perform), pulmonary function tests (PFTs) 
and PUL 2.0 for confirmation of eligibility.  
NOTE: Eligibility as described in Section 4.2.  If time between these functional 
assessments and the planned Baseline visit is to exceed 12 weeks (84 days), then these 
should be repeated and eligibility (re)confirmed prior to enrolling the subject.

Questionnaires: C-SSRS:

FOR ALL SUBJECTS AGED ≤12 YEARS AT SCREENING: Children’s 
Baseline/Screening (Version 6/23/10);

FOR ALL SUBJECTS AGED >12 YEARS AT SCREENING: 
Baseline/Screening (Version 1/14/09);

Existing symptoms and/or applicable AE monitoring.
6.2. Visit 2 (Baseline): Day -16 (-12 to +2 days) 
As described in Section 5.3.1, because 2 weeks are required to ship PF-06939926 to the site 
for each subject enrolled, the Baseline visit must occur at least 2 weeks prior to the Dosing 
visit.  
In addition, even though a subject may be registered (ie, enrolled) following confirmation of 
eligibility during the Screening period, a repeat blood draw to confirm that the subject still 
has no NAb against AAV9 above the threshold per the testing laboratory will be obtained 
prior to the Dosing visit but will only be analyzed if required.  If there were evidence of 
seroconversion, the subject would be discontinued from the study prior to receipt of 
PF-06939926.
This visit may be conducted over 1 or 2 days as determined by the site.  Assessments during 
Visit 2 include:

Physical and neurological examination; 

Height and Weight Baseline weight will be used to enroll the subject and to determine 
the number of investigational product vials to be shipped to the site (see above, 
Section 5.3.1); and below, Section 7.2.4, for guidance on obtaining height and weight 
measurements from non-ambulatory subjects); 

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•
Vital signs: Blood pressure, pulse rate, respiratory rate, and, if clinically indicated, body 
temperature.
•
Clinical laboratory assessments: 
•
Blood samples:
•
Clinical safety, including hematology, chemistry and other labs as described in 
Table 1;
 
 
•
Functional Assessments: 
•
Activity monitoring: Activity monitor(s) may be placed on the subjects to wear 
just prior to the functional assessments and then continuously for the next 
2 weeks;
•
FOR AMBULATORY SUBJECTS: Ambulatory status, PFTs, 4SC, NSAA, PUL, 
Strength, 6MWT, in same order when possible;
•
FOR NON-AMBULATORY SUBJECTS: Ambulatory status, PFTs, PUL, Strength, 
in same order when possible.
•
Muscle biopsies: in those subjects in which a baseline biopsy is obtained, it will be 
performed under anesthesia preferably after the functional assessments.  If baseline 
muscle biopsies have been obtained outside this study and (1) can be shipped to a 
sponsor’s designated laboratory for use in this study, and (2) are deemed by the sponsor 
to be of sufficient quantity and quality, then these may replace the/ need for an additional 
baseline biopsy;
•
Questionnaires: With exception of C-SSRS to confirm safety, subjects and/or caregivers 
can still participate in the study even if unwilling or unable to provide self-reported data:
•
C-SSRS:
•
FOR ALL SUBJECTS WHO WERE ō12 YEARS OLD AT SCREENING:
Children’s Since Last Visit (Version 6/23/10);
•
FOR ALL SUBJECTS WHO WERE AGED >12 YEARS OLD AT 
SCREENING: Since Last Visit (Version 1/14/09);
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 Ŏ
 
 
 
 
 
 
 
 
 
 
•
Baseline symptoms and/or applicable AE monitoring;
•
Concomitant medication monitoring; 
•
Meningococcal vaccine, if applicable: Subjects who have no contraindications 
and who have not previously received a MenACWY must receive at least 1 dose 
of a meningococcal vaccination at least 30 days prior to administration of 
PF-06939926, as described in Section 5.7.1.
•
Registration (ie, enrollment): Once the subject’s weight has been obtained that this 
visit, the site should promptly enroll the subject, which will trigger the request for 
investigational product shipment (Section 5.3.1).  
6.3. Visit 3 (Dosing): Day 1 ±24-hour Monitoring during In-patient Stay (ie, Day 2), and 
Days 4, 7, and 10 (±1 Day)
Prior to dosing the subject, the investigator should ensure that the subject has not had any 
clinically significant infection within 30 days prior to dosing (eg, pneumonia).  If a subject 
does develop such an infection, the Dosing visit may be re-scheduled and/or additional 
assessments may need to be repeated to ensure that continuation of the subject is still 
appropriate.
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In addition, confirmation of a negative NAb test result from the Baseline visit is required in 
order to proceed with administration of PF-06939926 (Section 6.2).
The following assessments to be performed prior to study drug administration:
•
Vital signs: Blood pressure, pulse rate, respiratory rate, and body temperature, within 
approximately 30 minutes prior to infusion;
•
Triplicate 12-lead ECG: approximately one hour prior to infusion;
•
Clinical laboratory assessments:
•
Blood samples:
•
Clinical safety, including hematology, chemistry,
and other labs as described in Table 1, but excluding creatine kinase 
myocardial b fraction (CK-MB);
•
Ő2 mg/kg IV methylprednisolone administration to be fully delivered between 1 and 
4 hours prior to investigational drug infusion.
Dosing (Day 1 only):
•
Investigational product administration.  See Section 5.4.
Subjects will be monitored in-patient for at least 24 hours, and discharged on Day 2 (or 
longer if deemed necessary per the investigator) as follows:
•
Vital signs: 30 minutes, 1, 2, 4, 8, and 24 hours after the start of infusion (as described 
above);
•
Triplicate 12-lead ECG: upon completion of the infusion (+30 minutes) and as 
clinically indicated.
•
Clinical laboratory assessments (prior to discharge and as clinically indicated):
•
Blood samples: Clinical safety (Table 1), but excluding CK-MB.
 
 
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•
AE monitoring: to include infusion site reaction monitoring.  Subjects who experience 
an AE possibly related to study drug should not be discharged until the event has 
resolved or can be managed by subject and/or caregiver (eg, administered oral 
antiemetics effectively stop vomiting events);
•
Concomitant medication monitoring;
•
Oral prednisone or prednisolone: Starting the day after the infusion of PF-06939926 
(ie, Day 2), subjects will initiate oral prednisone or prednisolone at Ŏ2 mg/kg/day for 
2 weeks post-investigational product administration.  Confirmation of compliance 
may be collected via a subject dosing diary, but must be specifically discussed and 
documented during all visits.
•
Oral and/or IV antiemetics: At the discretion of the investigator and/or request by the 
sponsor within a day following infusion of PF-06939926 (ie, Day 2), subjects may be 
administered antiemetics (eg, ondansetron) for approximately 7-10 days to prevent 
symptoms of nausea and vomiting. 
Upon discharge on Day 2 (or later if clinically indicated), subjects should be asked to 
stay local to the investigational site (ie, if they do not live near the investigational site, 
they should be asked to stay in an overnight facility) through at least the Day 14 
(Week 2) visit, or longer.  
Subjects will return to the site on Days 4, 7 , and 10 (±1 day) for the following 
assessments: 
•
Vital signs: Blood pressure, pulse rate, respiratory rate, and body temperature;
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1) including 
but 
excluding CK-MB;
 
 
NOTE: Blood and urine samples will also be collected on Days 5-9 or longer, as 
clinically indicated, for local laboratory testing to better understand the timing of any 
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changes indicative of an immune response during this period, as well as allow for 
increased safety monitoring and medical management to reduce the risk of adverse 
events.
•
AE monitoring: to include infusion site reaction monitoring.
•
Concomitant medication monitoring, including confirmation of compliance with 
increased daily oral prednisone or prednisolone prescription, as well as corresponding 
dosing diary, if available. 
•
Fluid intake/output: review with caregiver that subject has adequate fluid intake and 
output, as described in Section 4.5.1.
6.4. Visit 4 (Week 2): Day 14 ±1 Day
Assessments to be performed at this visit include:
•
Brief physical and neurological examination;
•
Vital signs: Blood pressure, pulse rate, respiratory rate, and body temperature;
•
Triplicate 12-lead ECG;
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1), including 
 but 
excluding CK-MB;
•
Questionnaires: C-SSRS:
•
FOR ALL SUBJECTS WHO WERE ō12 YEARS OLD AT SCREENING:
Children’s Since Last Visit (Version 6/23/10).
•
FOR ALL SUBJECTS WHO WERE AGED >12 YEARS OLD AT SCREENING:
Since Last Visit (Version 1/14/09).
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•
AE monitoring, including infusion site reaction monitoring;
•
Concomitant medication monitoring; 
•
Oral prednisone or prednisolone: Subjects will taper the oral prednisone or 
prednisolone dose to Ŏ1 mg/kg/day for the remainder of the 1st month post-
investigational product administration, or return to their pre-study daily doses of 
prednisone or prednisolone, whichever is higher.  Confirmation of compliance may 
be collected via a subject dosing diary, but must be specifically discussed and 
documented during this visit.
•
Fluid intake/output: review with caregiver that subject has adequate fluid intake and 
output, as described in Section 4.5.1.
6.5. Remote Visits 5, 7, 9, 11.1, 11.2, 11.3, 12.1, 12.2 (Weeks 3, 6, 10, 15, 19, 22, 32, 39): 
Days 21, 45, 75 ±3 Days, and Days 106, 135, 155, 225, 270 ±7 Days 
The assessments at these visits may be performed remotely unless clinical concern or subject 
preference warrants an in-person visit.  In the case of a remote visit, the site will coordinate a 
local phlebotomist to perform the sample collections at the subject’s home.
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1), including 
excluding CK-MB (Week 3 only); 
•
Wellness check-in: Site staff will follow-up by contacting the subject and/or caregiver to 
discuss any new adverse events and/or changes to concomitant medications, including 
compliance with daily oral prednisone or prednisolone.
•
Week 3 check-in will also include confirmation of adequate fluid intake and output, as 
described in Section 4.5.1.
•
Activity monitoring (only at Week 39) Activity monitors will be sent to the subject’s 
home to wear continuously for the next 2 weeks in free-living conditions.  
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6.6. Visit 6 (Week 4): Day 30 ±3 Days
Assessments to be performed at this visit include:
•
Brief physical and neurological examination;
•
Vital signs: Blood pressure, pulse rate, respiratory rate, and body temperature;
•
Triplicate 12-lead ECG;
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1), including 
as 
well as re-start collection of CK-MB going forward; 
•
AE monitoring, including infusion site monitoring;
•
Concomitant medication monitoring; 
•
Oral prednisone or prednisolone: subjects will taper the oral prednisone or 
prednisolone dose to a minimum of 0.75 mg/kg/day for 1 month or return to their 
pre-study daily doses of prednisone or prednisolone, whichever is higher.  
Confirmation of compliance may be collected via a subject dosing diary, but must be 
specifically discussed and documented during this visit.
•
Fluid intake/output: review with caregiver that subject has adequate fluid intake and 
output, as described in Section 4.5.1.
6.7. Visit 8 (Week 8): Day 60 ±3 Days 
The assessments to be performed at this visit include:
•
Brief physical and neurological examination.
•
Height and Weight;
•
Vital signs: Blood pressure, pulse rate, respiratory rate, and if clinically indicated, body 
temperature;
•
Triplicate 12-lead ECG;
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•
Clinical laboratory assessment:
•
Blood sample: 
•
Clinical safety (Table 1)
 
 
•
Muscle biopsies: if applicable, it will be performed under anesthesia either at this visit or 
the Week 12 (Day 90) visit, as determined by the sponsor and investigator;
•
AE monitoring including infusion site monitoring;
•
Concomitant medication monitoring; 
•
Oral prednisone or prednisolone: subjects will taper the oral prednisone or 
prednisolone dose to a minimum of 0.5 mg/kg/day for 1 month or return to their 
pre-study daily doses of prednisone or prednisolone, whichever is higher.  
Confirmation of compliance may be collected via a subject dosing diary, but must be 
specifically discussed and documented during this visit.
6.8. Visit 10 (Week 12): Day 90 ±3 days 
The assessments to be conducted at this visit include:
•
Brief physical and neurological examination;
•
Vital signs;
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1);
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•
Functional Assessments:
•
Activity monitoring: Activity monitors will again be placed on the subjects to wear 
just prior to the functional assessments and then continuously for the next 2 weeks;
•
FOR AMBULATORY SUBJECTS: Ambulatory status, PFTs, 4SC, NSAA, PUL, 
Strength, 6MWT;
•
FOR NON-AMBULATORY SUBJECTS: Ambulatory status, PFTs, PUL, Strength.
NOTE: These assessments are conducted at the site and should be assessed in the same 
order and preferably at around the same time of day as performed at Baseline.
 
 
•
Muscle biopsies: if applicable, it will be performed under anesthesia at this visit only if 
not already obtained at the Week 8 (Day 60) visit, and preferably after all functional 
assessments (above);
•
AE monitoring;
•
Concomitant medication monitoring; 
•
Oral prednisone or prednisolone: subjects will return to their pre-study 
glucocorticoid daily dose level, unless clinically indicated.  Compliance with this 
daily glucocorticoid regimen must be specifically discussed and documented during 
this visit. 
6.9. Visit 12 (Week 26): Day 180 ±7 Days 
If possible and reasonable as determined by the site, this visit may be split across 2 days 
within the visit window, with imaging and functional assessments performed on separate 
days.
This visit would include the following:
•
Brief Physical Examination and Neurological Examination;
•
Height and Weight;
•
Vital Signs;
•
Triplicate 12-lead ECG.
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•
Clinical laboratory assessments:
•
Blood samples:
•
Clinical safety (Table 1);
 
•
Functional Assessments: 
•
Activity monitoring: Activity monitors will again be placed on the subjects to wear 
just prior to the functional assessments and then continuously for the next 2 weeks;
•
FOR AMBULATORY SUBJECTS: Ambulatory status, PFTs, 4SC, NSAA, PUL, 
Strength, 6MWT;
•
FOR NON-AMBULATORY SUBJECTS: Ambulatory status, PFTs, PUL, Strength.
NOTE: These assessments are conducted at the site and should be assessed in the same 
order and preferably at around the same time of day as performed at Baseline.
•
Muscle biopsies: if applicable, it will be performed under anesthesia either at this visit or 
the Week 52 (Day 360) visit, as determined by the sponsor and investigator, and 
preferably after all imaging and functional assessments (above);
•
AE monitoring;
•
Concomitant medication monitoring, including compliance with the required daily 
glucocorticoid regimen.
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6.10. Visit 13 (Week 52): Day 360 ±7 Days 
If possible and reasonable as determined by the site, this visit may be split across 2 or 3 days 
within the visit window, with imaging and functional assessments performed on separate 
days.
This visit would include the following:
•
Brief Physical Examination and Neurological Examination;
•
Height and Weight;
•
Vital Signs;
•
Triplicate 12-lead ECG;
•
Clinical laboratory assessments:
•
Blood samples:
•
Clinical safety (Table 1);
•
Imaging Assessments: 
 
•
Cardiac MRI should be performed after thigh and upper limb MRI or on different 
days.  If the cardiac MRI is unable to be evaluated due to quality, it will either be 
repeated or, if necessary, substituted by a locally-read echocardiogram.
•
Functional Assessments: 
•
Activity monitoring: Activity monitors will again be placed on the subjects to wear 
just prior to the functional assessments and then continuously for the next 2 weeks;
•
FOR AMBULATORY SUBJECTS: Ambulatory status, PFTs, 4SC, NSAA, PUL, 
Strength, 6MWT;
•
FOR NON-AMBULATORY SUBJECTS: Ambulatory status, PFTs, PUL, Strength.
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NOTE: These assessments are conducted at the site and should be assessed in the same 
order and preferably at around the same time of day as performed at Baseline.
 
 
•
Muscle biopsies: if applicable, it will be performed under anesthesia at this visit only if 
not already obtained at the Week 26 (Day 180) visit, and preferably after the imaging and 
functional assessments (above);
•
AE monitoring.
•
Concomitant medication monitoring, including compliance with the required daily 
glucocorticoid regimen.
6.11. Visits 14, 15, 16, 17 (Long-term Follow-up Phase Years 2-5): Annually - Days 730, 
1095, 1460, 1825 ±30 Days or Early Termination
If possible and reasonable as determined by the site, this visit may be split across 2 or 3 days 
within the visit window, with imaging and functional assessments performed on separate 
days.
This visit would include the following:
•
Brief Physical Examination and Neurological Examination;
•
Height and Weight;
•
Vital Signs;
•
Triplicate 12-lead ECG;
•
Clinical laboratory assessments:
•
Blood samples:
•
Clinical safety (Table 1);
 
 
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•
Muscle biopsies: will be performed under anesthesia preferably after the imaging and 
functional assessments (below), but only in the event of an Early Termination visit and
with subject/caregiver consent provided that the subject has not yet completed the 
maximum of 3 procedures.  No subject will undergo biopsies at more than 3 total visits. 
•
Imaging Assessments: 
 
•
Cardiac MRI should be performed after thigh and upper limb MRI or on different 
days.  If the cardiac MRI is unable to be evaluated due to quality, it will either be 
repeated or, if necessary, substituted by a locally-read echocardiogram.
•
Functional Assessments: 
•
Activity monitoring: Activity monitors will again be placed on the subjects to wear 
just prior to the functional assessments and then continuously for the next 2 weeks;
•
FOR AMBULATORY SUBJECTS: Ambulatory status, PFTs, 4SC, NSAA, Strength, 
PUL, 6MWT; 
•
FOR NON-AMBULATORY SUBJECTS: Ambulatory status, PFTs, PUL, Strength.
NOTE: These assessments are conducted at the site and should be assessed in the same 
order and preferably at around the same time of day as performed at Baseline.
 
 
•
AE monitoring;
•
Concomitant medication monitoring.
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6.12. Remote Visits 13.1, 14.1, 15.1, 16.1 (Long-term Follow-Up Phase Years 1.5, 2.5, 
3.5, 4.5): Days 545, 910, 1275, 1640 ±30 Days 
The assessments at these visits may be performed remotely unless clinical concern or subject 
preference warrants an in-person visit.  In the case of a remote visit, the site will coordinate a 
local phlebotomist to perform the sample collections at the subject’s home.
•
Clinical laboratory assessment:
•
Blood sample:
•
Clinical safety (Table 1); 
•
Wellness check-in: Site staff will follow-up by contacting the subject and/or caregiver to 
discuss any new adverse events and/or changes to concomitant medications.
6.13. Subject Withdrawal
6.13.1. Withdrawal of Consent
Subjects will receive only one dose of investigational product.  However, given the nature of 
gene transfer, the gene remains in the body for a long period of time.  Therefore, subjects are 
followed for 5 years post administration of PF-06939926.  The only exception to this is when 
a subject or parent or legal guardian on behalf of the subject specifically withdraws consent 
for any further contact with him or her or persons previously authorized by the subject to 
provide this information.  Subjects or parent(s) or legal guardian(s) should notify the 
investigator in writing of the decision to withdraw consent from future follow-up, whenever 
possible.  The withdrawal of consent should be explained in detail in the medical records by 
the investigator, as to whether the withdrawal is from study procedures and/or post-treatment 
study follow-up, and entered on the appropriate CRF page.  In the event that vital status 
(whether the subject is alive or dead) is being measured, publicly available information 
should be used to determine vital status only as appropriately directed in accordance with 
local law.
Subjects may withdraw from the study at any time at their own request, or they may be 
withdrawn at any time at the discretion of the investigator or sponsor for safety (see also the 
Withdrawal From the Study Due to Adverse Events Section 8.1.3) or behavioral reasons, or 
the inability of the subject to comply with the protocol-required schedule of study visits or 
procedures at a given study site. 
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If a subject does not return for a scheduled visit, every effort should be made to contact the 
subject.  All attempts to contact the subject and information received during contact attempts 
must be documented in the subject’s medical record.  In any circumstance, every effort 
should be made to document subject outcome, if possible.  The investigator should inquire 
about the reason for withdrawal, request that the subject return for a final visit, if applicable, 
and follow up with the subject regarding any unresolved adverse events (AEs).
It may be appropriate for the subject to return to the clinic for final safety assessments and to 
be questioned regarding their reason for withdrawal.  The Early Termination assessments 
may be performed according to the Schedule of Activities and Section 6.11.
If the subject withdraws from the study, and also withdraws consent for disclosure of future 
information, no further evaluations should be performed, and no additional data should be 
collected.  The sponsor may retain and continue to use any data collected before such 
withdrawal of consent.
6.13.2. Lost to Follow-up 
All reasonable efforts must be made to locate subjects to determine and report their ongoing 
status.  This includes follow-up with persons authorized by the subject as noted above.  Lost 
to follow-up is defined by the inability to reach the subject after a minimum of 2 documented 
phone calls, faxes, or e-mails as well as lack of response by the subject to 1 registered mail 
letter.  All attempts should be documented in the subject’s medical records.  If it is 
determined that the subject has died, the site will use locally permissible methods to obtain 
the date and cause of death.  If the investigator’s use of a third-party representative to assist 
in the follow-up portion of the study has been included in the subject’s informed consent, 
then the investigator may use a sponsor-retained third-party representative to assist site staff 
with obtaining the subject’s contact information or other public vital status data necessary to 
complete the follow-up portion of the study.  The site staff and representative will consult 
publicly available sources, such as public health registries and databases, in order to obtain 
updated contact information.  If, after all attempts, the subject remains lost to follow-up, then 
the last-known-alive date as determined by the investigator should be reported and 
documented in the subject’s medical records.
7. STUDY ASSESSMENTS
Every effort should be made to ensure that the protocol-required tests and procedures are 
completed as described.  However, it is anticipated that from time to time there may be 
circumstances, outside of the control of the investigator that may make it unfeasible to 
perform the test.  In these cases, the investigator will take all steps necessary to ensure the 
safety and well-being of the subject.  When a protocol-required test cannot be performed, the 
investigator will document the reason for this and any corrective and preventive actions that 
he or she has taken to ensure that normal processes are adhered to as soon as possible.  
The sponsor study team will be informed of these incidents in a timely manner.
In the event that a subject becomes intolerant to MRI scanning (eg, loses ambulation), the 
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MRI when possible.  Other assessments may be modified or deemed not applicable to non-
ambulatory subjects, as described below.  
 
 
7.1. Blood Volume
While frequent blood collection, particularly within the first few months after receiving 
PF-06939926, is critical to ensure subject safety in this study, blood volume limits have been 
set for this pediatric patient population according to those described in the Bulletin of the 
World Health Organization.66  In accordance with these recommendations, compiled from 
5 studies and 9 sets of guidelines, blood sampling should not exceed 5% based on an 
estimated total blood volume of 75-80 mL/kg within a 24-hour period, or 10% of this volume 
within an 8-week period, even at the minimum weight required for participation in this study 
(ie, 15 kg).  
7.2. Safety
7.2.1. Clinical Laboratory
The following safety laboratory tests will be performed at times defined in the Schedule of 
Activities section of this protocol.  Additional laboratory values may be reported as a result 
of the method of analysis or type of analyzer used by the clinical laboratory, or as derived 
from calculated values.  Such tests would not require additional collection of biospecimens.  
Unscheduled clinical labs may be obtained at any time during the study to assess any 
perceived safety concerns.  If a subject has a peripherally inserted central catheter (PICC) 
line, it must only be used for blood collections and not for study drug administration.
Detailed collection, processing, storage, and shipment instructions will be provided in the 
central laboratory manual.
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Table 1.
Central Laboratory Tests
Hematology
Chemistry
Urinalysis
Other
Hemoglobin
Hematocrit
Red blood cell (RBC) 
count
Platelet count
White blood cell count 
(and morphology as 
applicable)
Total neutrophils (Abs)
Absolute neutrophils 
(ANC)
Eosinophils (Abs)
Monocytes (Abs)
Basophils (Abs)
Lymphocytes (Abs)
Red blood cell indices 
(mean corpuscular 
volume, mean 
corpuscular 
hemoglobin, mean 
corpuscular 
hemoglobin 
concentration)
Haptoglobinc
BUN and Creatinine
Glucose 
Calcium
Sodium
Potassium
Magnesiuma
Chloride
Total 
CO2 (Bicarbonate)
AST, ALT,
Total Bilirubin (direct 
and indirect bilirubin)
Alkaline phosphatase
Uric acid
Albumin
Total protein
Serum Phosphorus
Cystatin C
Creatine kinase
Creatine kinase 
myocardial b fraction 
(CK-MB)d
Amylase
Lipase 
GGT
C-reactive protein 
(CRP)
Cardiac troponin I
Dipstick Analysis:
pH
Glucose (qual)
Protein (qual)
Blood (qual)
Ketones
Nitrites
Leukocyte esterase
Microscopyb
PT
aPTT
Glutamate dehydrogenase 
(GLDH) 
 
 
 
Immunogenicity:
 
 
mini-dystrophin
ADA anti-virus immune 
response, binding Ab
For screening only: 
DMD genetic test (if required 
to confirm DMD diagnosis) 
International normalized ratio 
(INR); Hepatitis A virus 
(anti-HAV) 
immunoglobulin M 
Hepatitis B antigen
Hepatitis C antibody, 
anti-nuclear antibody, total 
 
Additional Tests (repeats for any potential cases of drug-induced liver injury)
AST, ALT (repeat)
Total bilirubin (repeat)
Albumin (repeat)
Alkaline phosphatase (repeat)
Direct bilirubin
Indirect bilirubin
Creatine kinase
CK-MB
GGT
GLDH
PT
Genetic Testing for a-HUS-Central Laboratory for subjects who experience an event compatible with aHUS
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Table 1.
Central Laboratory Tests
a.
Magnesium will be collected on Day 1, Day 7, and Day 14.
b.
Only if urine dipstick is positive for blood, protein, nitrites or leukocyte esterase. 
d.
CK-MB will be collected at all planned visits with the exception of Dosing Day 1 until Week 4, at which 
point it will be collected at all planned visits for the remainder of study participation.
Biospecimen samples will also be collected for local laboratory testing as described in the 
Schedule of Activities.  At a minimum these will include hematology, chemistry and 
urinalysis testing.
7.2.2. Physical Examinations
Physical examinations may be conducted by a physician, trained physician's assistant, or 
nurse practitioner as acceptable according to local regulation.  The full physical examination 
will include head, ears, eyes, nose, mouth, skin, heart and lung examinations, lymph nodes, 
gastrointestinal, and musculoskeletal systems.  Abnormal findings will be further 
characterized as “clinically significant” or “not clinically significant” for the purposes of 
reporting as adverse events. 
7.2.2.1. Brief Physical Examinations
Only brief physical examinations will be performed post-baseline unless safety concerns 
warrant full examination.  These may be conducted by a physician, trained physician's 
assistant, or nurse practitioner as acceptable according to local regulation.  The brief physical 
examination will include general appearance, chest (heart and lungs), abdomen, 
musculoskeletal (joints, tenderness, presence of new fractures, joint contractures). 
7.2.3. Neurological Examination
Only brief neurological examinations will be performed post-baseline unless safety concerns 
warrant full examination.  These will be conducted by a neurologist.  The neurological 
examination will include Mental Status, cranial nerves II-XII, motor (upper and lower limb 
bulk strength), deep tendon reflexes, sensory testing, station and gait, and coordination.
FOR NON-AMBULATORY SUBJECTS: Only those domains of the neurological examination 
deemed safe and appropriate for non-ambulatory subjects will be performed, as determined 
by the examiner (eg, exclusion of station and gait). 
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7.2.3.1. Brief Neurological Examination 
A brief neurological examination will be conducted by a neurologist.  The brief neurological 
examination will include motor (bulk strength, right and left separately, both upper and lower 
limbs separately) and station and gait.
FOR NON-AMBULATORY SUBJECTS: As above, domains of this examination will only be 
performed if they are deemed safe and appropriate. 
7.2.4. Height and Weight Measurements
Preferably both height and weight measurements will be collected in the morning.
7.2.4.1. Height 
FOR NON-AMBULATORY SUBJECTS: If a subject is unable to stand safely, an estimated 
height can be calculated using the subject’s ulnar length and the instructions provided in the 
Functional Assessment Manual.
7.2.4.2. Weight
For measuring weight, a calibrated scale with appropriate range and resolution is to be used 
and must be placed on a stable, flat surface.  Subjects must remove shoes, bulky layers of 
clothing, and jackets so that only light clothing remains. They must also remove the contents 
of their pockets and remain still during measurement of weight. 
FOR NON-AMBULATORY SUBJECTS: Body weights may be measured using a calibrated 
chair scale or wheelchair scale (eg, subtract the wheelchair weight from the total weight), or 
other method with agreement from the sponsor, since body weight is required to determine 
the dose of PF-06939926 for each subject.  To obtain as accurate a measurement as possible, 
all other contents besides the subject (eg, blankets, items in chair pockets, etc.) should be 
removed from the wheelchair before rolling onto the scale.   
Preferably both height and weight measurements will be collected in the morning.
7.2.5. Vital Signs
Respiratory rate should be measured after approximately 5 minutes rest by observing and 
counting the respirations of the subject for 30 seconds and multiplied by 2.  Preferably, 
respiratory rate will be obtained just before blood pressure measurement, and ideally the 
position of the subject during the measurement (e.g., sitting or supine) will be consistent for 
each collection from a given subject.
Blood pressure, pulse rate, and respiratory rate will be measured at times specified in 
Schedule of Activities section of this protocol.  Unscheduled collection times will be 
permitted, as necessary, to ensure appropriate collection of safety data.
Blood pressure will be measured with the subject’s arm supported at the level of the heart, 
and recorded to the nearest mm Hg after at least 5 minutes of rest.  Whenever possible, the 
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the measurement should be taken while the subject is in the same position (eg, sitting or 
supine). 
Wherever possible, the same size blood pressure cuff, which has been properly sized and 
calibrated, will be used to measure blood pressure each time.  The use of automated devices 
for measuring BP and pulse rate are acceptable, although, when done manually, pulse rate 
will be measured in the brachial/radial artery for at least 30 seconds. 
Body temperature will also be collected at the times specified in the Schedule of Activities
section of this protocol, and as clinically indicated.
7.2.6. Triplicate Electrocardiogram (ECG)
ECGs should be collected in triplicate at times specified in the Schedule of Activities section 
of this protocol.
All scheduled ECGs should be performed after the subject has rested quietly for at least 
10 minutes in a supine position.
To ensure safety of the subjects, a qualified individual at the investigator site will make 
comparisons to baseline measurements.  The QTc interval should be recorded using the 
QTcF (QTc Fridericia) value in milliseconds. 
If the QTc interval is increased by ≥45 msec from the baseline, or an absolute QTc value is 
≥500 msec for any scheduled ECG, then 2 additional ECGs will be collected, approximately 
2-4 minutes apart, to confirm the original measurement.  If either of the QTc values from 
these repeated ECGs remains above the threshold value (≥45 msec from the baseline, which 
for this study would be on Day 1, prior to receiving PF-06939926; or is ≥500 msec), then a 
single ECG must be repeated at least hourly until QTc values from 2 successive ECGs fall 
below the threshold value that triggered the repeat measurement. 
If QTcF values remain ≥500 msec (or ≥45 msec from the baseline) for greater than 4 hours 
(or sooner at the discretion of the investigator); or QTcF intervals get progressively longer, 
the subject should undergo continuous ECG monitoring.  A cardiologist should be consulted 
if QTcF intervals do not return to less than 500 msec (or to <45 msec above the baseline) 
after 8 hours of monitoring (or sooner at the discretion of the investigator).
In some cases, it may be appropriate to repeat abnormal ECGs to rule out improper lead 
placement as contributing to the ECG abnormality.  It is important that leads are placed in the 
same positions each time in order to achieve precise ECG recordings.  If a machine-read 
QTcF value is prolonged, as defined above, repeat measurements may not be necessary if a 
qualified physician’s interpretation determines that the QTcF values are in the acceptable 
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7.2.7. Safety Imaging
7.2.7.1. Management of Incidental Findings
An incidental finding is one unknown to the subject that has potential health or reproductive 
importance, which is discovered unexpectedly in the course of a research study, but is 
unrelated to the purpose and beyond the aims of the study.
MRI will be reviewed by a central review facility.  The purpose of this review is to evaluate 
images for muscle changes or cardiac safety.  Central image review is not a complete medical 
review of the subject.  If during the central review process, an unexpected observation is 
identified and this finding could, in the opinion of the central reviewer, have a significant 
health or reproductive consequence, this finding may be shared with the study sponsor for 
disclosure to the principal investigator.  All follow-up testing and final diagnosis will be left 
to the discretion of the medical professionals at the site or those with an existing 
physician-patient relationship.  The principal investigator will be responsible for reporting 
any adverse events identified from incidental findings as described in the Section 8.  
Identification of such incidental findings during the central review process should not be 
expected, and the site maintains responsibility of performing a general safety review of all 
images as per site protocols.  
7.2.7.2. Cardiac MRI (or Echocardiogram, if necessary)
Cardiac MRI should be collected at times specified in the Schedule of Activities section of 
this protocol.
Cardiac MRI with gadolinium is the preferred method for cardiac imaging, when possible.  
When cardiac MRI with gadolinium is used, it should only be collected after thigh and upper 
limb MRI is complete.  Otherwise cardiac MRI should be done on a different visit day from 
the thigh and upper limb MRI.  If the subject has a contraindication to gadolinium, cardiac 
MRI without gadolinium will be acceptable.  Cardiac MRI will be read by a central imaging 
vendor and only the results of the LVEF will be provided to sites.  
FOR AMBULATORY SUBJECTS: If the LVEF falls below 50% on the cardiac MRI at any 
follow-up visit, the subject should be referred to a cardiologist for further assessment.  
FOR NON-AMBULATORY SUBJECTS: For those non-ambulatory subjects for whom the 
LVEF is already <50% at Screening, documentation of consultation with a cardiologist at 
least annually should be kept on file as part of standard of care.
Sites will be provided with a scanning and image transmittal guide for collection of the 
cardiac MRI.
If the cardiac MRI is deemed unable to be evaluated and a repeat MRI is unlikely to resolve 
the issue (eg, if subject is unable to remain still in the scanner), a locally-read 
echocardiogram may be an acceptable substitute.  To ensure safety of the subjects, a qualified 
individual at the site will evaluate the echocardiogram at least for LVEF, but other 
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left ventricular mass index, left ventricular end diastolic diameter, left ventricular end 
systolic diameter, shortening fraction, left ventricular posterior wall thickness, tricuspid 
valvular regurgitation presence and pericardial effusion.  
7.2.8. Suicidal Ideation and Behavior Assessment 
FOR ALL SUBJECTS AGED ≤12 YEARS AT SCREENING: The Columbia Suicide 
Severity Rating Scale (C-SSRS) Children’s Baseline/Screening (Version 6/23/10) will be 
completed at Screening and the C-SSRS: Children’s Since Last Visit (Version 6/23/10) will 
be evaluated at the subsequent times specified in the Schedule of Activities.  Given the 
sensitive nature of the subject matter of this assessment, the C-SSRS will be conducted with 
the subject’s care giver/legal guardian on the subject’s behalf throughout the study for 
subjects who are 12 years of age and younger at Screening, rather than administering this 
evaluation directly with these study subjects. 
FOR ALL SUBJECTS AGED >12 YEARS AT SCREENING: The C-SSRS 
Baseline/Screening version (Version 1/14/09) will be completed at Screening, covering both 
lifetime and the past 6 months/0.5 year, and the C-SSRS Since Last Visit (Version 1/14/09) 
will be evaluated at the subsequent times specified in the Schedule of Activities.  Subjects 
>12 years old at Screening will complete these assessments themselves.  However, upon 
request, site staff may support the physical completion of this assessment on behalf of the 
subject if, for example, a subject is unable to record responses due to loss of upper limb 
function.
At Screening, if the subject endorses a 4 or 5 on the C-SSRS ideation section or reports any 
suicidal behavior, then the subject is not eligible for study participation and an evaluation of 
suicide risk (risk assessment) must be completed. 
Risk Assessment: In the event that a subject endorses a 4 or 5 on the C-SSRS ideation 
section or reports any suicidal behavior, an evaluation of suicide risk (risk assessment) will 
be completed as part of the psychiatric evaluation and assessment of subject safety to 
participate will be performed by the following child and adolescent mental health provider 
(MHP): In the US: 1) Child and Adolescent Psychiatrists (board certified or board eligible), 
2) psychiatrist who have training and experience in the diagnosis and treatment of psychiatric 
disorders in the pediatric population, or 2) Psy. D. or Ph.D. level Clinical Psychologists, 
licensed Master’s level Clinical Social Workers (MSW) or licensed Psychiatric Nurse 
Practitioners (PNP) who have training and experience in the diagnosis and treatment of 
psychiatric disorders in the pediatric population.
Written documentation of the risk assessment should be included in the subject’s source 
documentation and the risk assessment CRF will be completed.  The risk assessment CRF 
serves as further verification that the psychiatric evaluation and assessment of subject safety 
have been completed for all subjects endorsing items 4 or 5 on the C-SSRS ideation section 
or reporting suicidal behavior.
Additional details regarding these assessments, including training and any additional 
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7.2.9. Concomitant Medication Monitoring
See Section 5.7.
7.2.9.1. Subject Dosing Diary
Subjects or caregivers on behalf of subjects may be required to complete dosing diaries to 
ensure compliance with the increased and then tapering dose levels of daily oral prednisone 
or prednisolone required for at least the first 3 months post-dose of PF-06939926.  Since 
these diaries were designed to be completed electronically, if not used, medication 
compliance, particularly with the required daily dose of glucocorticoids through the first 
year, is expected to at least be reviewed with the subject and/or caregiver and documented at 
all in-clinic and remote visits (ie, wellness check-ins).
7.2.10. Infusion Site Monitoring
From the initiation of the IV infusion and then at the times described in the Schedule of 
Activities, subjects will be monitored for signs of any infusion site reactions including but 
not limited to erythema, swelling, bruising, pain or pruritus.  
7.2.11. Wellness Check-in
Subjects will be contacted by the site at defined time-points and intervals as described in the 
Schedule of Activities, and as clinically indicated, to collect information on any adverse 
events experienced and/or updates to concomitant medications since the last contact with the 
subject.  These may also include confirmation of adequate fluid intake and output, as 
described in Section 4.5.1.  Written documentation of the Wellness Check-in will be included 
in the subjects’ source documentation and any adverse events or concomitant medication 
changes will be captured in the associated CRFs.
7.2.12. Triggers for Additional Safety Monitoring 
Should any of the following conditions be observed, the subject should be brought to the 
investigational site as soon as possible and within 24 hours for evaluation with the 
investigator or designated medically qualified individual:
•
No urine output for 24 hours and/or evidence of significant reduction in estimated 
glomerular filtration rate, such as determined by increases in serum cystatin C;
•
Abnormality on blood smear (indicating unequivocal hemolysis);
•
Platelet count <100 GI/L on repeat (ie, ×2).
Hospital admission and/or treatment with rescue medication, as per Section 5.8, may be 
warranted, as per the investigator and medical team’s and/or sponsor study team’s discretion.
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Cardiac Troponin I
For the first value >17 × ULN, and for any value >3× the most recent value:
•
Perform clinical evaluation for cardiac signs or symptoms; 
•
Repeat cTnI test within 24-48 hours after the result was received;
•
If cTnI remains persistently elevated or if signs or symptoms are observed or 
reported: perform ECG & consider cardiac consult.
For any value >33 × ULN, unless such elevation has occurred and been evaluated in the last 
3 months:
•
Perform clinical evaluation for cardiac signs or symptoms; 
•
Repeat cTnI test within 24-48 hours after the result was received;
•
Perform ECG and consider cardiac consult.
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
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7.6. Muscle Biopsies
In order to evaluate the expression and distribution of mini-dystrophin produced post-gene 
transfer relative to baseline, muscle biopsies will be collected according to the Schedule of 
Activities. 
Open muscle biopsies will be taken from the bicep brachii, and needle biopsies may be taken 
from other muscle groups, such as gastrocnemius and vastus lateralis, for each assessment.  
No subject will undergo biopsies at more than 3 total visits.  The biopsies will be conducted 
by a qualified surgeon with adequate experience with this specific procedure, as confirmed 
and approved by the sponsor beforehand.  This procedure will be performed using anesthesia 
(eg, regional block or under general anesthesia) according to institutional standards and 
specific instructions regarding post-operative care will also be provided to the subjects after 
the procedure. 
Unless instructed by Pfizer to site staff in writing, all subjects will undergo open muscle 
biopsies taken from the bicep brachii at Baseline and at approximately 2 and 12 months 
following receipt of PF-06939926.  Examples of explicit alternative instructions provided by 
Pfizer to site staff regarding biopsies for a given subject include the following:
•
FOR AMBULATORY SUBJECTS: Sites will be informed if needle biopsies will be 
collected in addition to open muscle biopsies for a particular subject at a specific 
timepoint, as well as from which specific muscle group(s).  
•
FOR NON-AMBULATORY SUBJECTS: For non-ambulatory subjects, only open 
muscle biopsies from the biceps brachii will be collected, and the option to reduce the 
total number of biopsies will be considered.  Sites will be informed if fewer biopsies 
will be collected for a given subject, as well as the timepoints for collection. 
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Detailed collection, processing, storage, and shipment instructions will be provided in the 
biopsy and central laboratory manuals.  Additional training on the aforementioned 
procedures will be provided by the sponsor or sponsor representative.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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8. ADVERSE EVENT REPORTING
8.1. Requirements
The table below summarizes the requirements for recording safety events on the CRF and for 
reporting safety events on the Clinical Trial (CT) Serious Adverse Event (SAE) Report Form 
to Pfizer Safety.  These requirements are delineated for 3 types of events: (1) SAEs; 
(2) non-serious adverse events (AEs); and (3) exposure to the investigational product under 
study during pregnancy or breastfeeding, and occupational exposure. 
Safety Event
Recorded on the CRF
Reported on the CT SAE 
Report Form to Pfizer Safety 
Within 24 Hours of Awareness
SAE
All
All
Non-serious AE
All
None
Exposure to the investigational 
product under study during 
pregnancy or breastfeeding,
and occupational exposure
All (regardless of whether 
associated with an AE), except 
occupational exposure
Exposure during pregnancy, 
exposure via breastfeeding, 
occupational exposure (regardless 
of whether associated with an AE)
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All observed or volunteered events regardless of treatment group or suspected causal 
relationship to the investigational product(s) will be reported as described in the following 
paragraphs.
Events listed in the table above that require reporting to Pfizer Safety on the CT SAE Report 
Form within 24 hours of awareness of the event by the investigator are to be reported 
regardless of whether the event is determined by the investigator to be related to an 
investigational product under study.  In particular, if the SAE is fatal or life-threatening, 
notification to Pfizer Safety must be made immediately, irrespective of the extent of available 
event information.  This time frame also applies to additional new (follow-up) information on 
previously forwarded reports.  In the rare situation that the investigator does not become 
immediately aware of the occurrence of an event, the investigator must report the event 
within 24 hours after learning of it and document the time of his/her first awareness of the 
event.
For each event, the investigator must pursue and obtain adequate information both to 
determine the outcome and to assess whether it meets the criteria for classification as an SAE 
(see the Serious Adverse Events section below).  In addition, the investigator may be 
requested by Pfizer Safety to obtain specific follow-up information in an expedited fashion.  
This information is more detailed than that recorded on the CRF.  In general, this will include 
a description of the event in sufficient detail to allow for a complete medical assessment of 
the case and independent determination of possible causality.  Any information relevant to 
the event, such as concomitant medications and illnesses, must be provided.  In the case of a 
subject death, a summary of available autopsy findings must be submitted as soon as possible 
to Pfizer Safety.  Any pertinent additional information must be reported on the CT SAE 
Report Form; additional source documents (eg, medical records, CRF, laboratory data) are to 
be sent to Pfizer Safety ONLY upon request.
As part of ongoing safety reviews conducted by the sponsor, any non-serious AE that is 
determined by the sponsor to be serious will be reported by the sponsor as an SAE.  To assist 
in the determination of case seriousness, further information may be requested from the 
investigator to provide clarity and understanding of the event in the context of the clinical 
study.
As noted in the Protocol-Specified Serious Adverse Events section, should an investigator 
judge one of the identified protocol-specified SAEs to have a causal relationship with the 
investigational product, the investigator must report the SAE to Pfizer Safety within 24 hours 
of investigator awareness.
8.1.1. Additional Details on Recording Adverse Events on the CRF
All events detailed in the table above will be recorded on the AE page(s) of the CRF.  It 
should be noted that the CT SAE Report Form for reporting of SAE information is not the 
same as the AE page of the CRF.  When the same data are collected, the forms must be 
completed in a consistent manner.  AEs should be recorded using concise medical 
terminology and the same AE term should be used on both the CRF and the CT SAE Report 
Form for reporting of SAE information.

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8.1.2. Eliciting Adverse Event Information
The investigator is to record on the CRF all directly observed AEs and all AEs spontaneously 
reported by the study subject/parent(s)/legal guardian/legally acceptable representative.  In 
addition, each study subject/parent(s)/legal guardian/legally acceptable representative will be 
questioned about the occurrence of AEs in a non-leading manner.
8.1.3. Withdrawal from the Study Due to Adverse Events (see also the Subject 
Withdrawal section)
Withdrawal due to AEs should be distinguished from withdrawal due to other causes, 
according to the definition of AE noted below, and recorded on the CRF. 
When a subject withdraws from the study because of an SAE, the SAE must be recorded on 
the CRF and reported, as appropriate, on the CT SAE Report Form, in accordance with the 
Requirements section above.
8.1.4. Time Period for Collecting AE/SAE Information
The time period for actively eliciting and collecting AEs and SAEs (“active collection 
period”) for each subject begins from the time the subject provides informed consent, which 
is obtained before the subject’s participation in the study (ie, before undergoing any 
study-related procedure and/or receiving investigational product), through and including a 
minimum of 1 year following administration of the investigational product, also referred to as 
the Treatment Phase.  In the Long-term Follow-up Phase (ie, Years 2 through 5), only SAEs 
and any AEs believed to be related to the investigational product will be reported. 
For subjects who are screen failures, the active collection period ends when screen failure 
status is determined.
8.1.4.1. Reporting SAEs to Pfizer Safety
All SAEs occurring in a subject during the active collection period are reported to Pfizer 
Safety on the CT SAE Report Form.
SAEs occurring in a subject after the active collection period has ended are reported to Pfizer 
Safety if the investigator becomes aware of them; at a minimum, all SAEs that the 
investigator believes have at least a reasonable possibility of being related to investigational 
product must be reported to Pfizer Safety.
Follow up by the investigator continues throughout and after the active collection period and 
until the event or its sequelae resolve or stabilize at a level acceptable to the investigator, and 
Pfizer concurs with that assessment.
8.1.4.2. Recording Non-serious AEs and SAEs on the CRF
During the active collection period, both non-serious AEs and SAEs are recorded on the 
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Follow-up by the investigator may be required until the event or its sequelae resolve or 
stabilize at a level acceptable to the investigator, and Pfizer concurs with that assessment.
8.1.5. Causality Assessment
The investigator’s assessment of causality must be provided for all AEs (serious and 
non-serious); the investigator must record the causal relationship on the CRF, and report such 
an assessment in accordance with the SAE reporting requirements, if applicable.  An 
investigator’s causality assessment is the determination of whether there exists a reasonable 
possibility that the investigational product caused or contributed to an AE; generally the facts 
(evidence) or arguments to suggest a causal relationship should be provided.  If the 
investigator does not know whether or not the investigational product caused the event, then 
the event will be handled as “related to investigational product” for reporting purposes, as 
defined by the sponsor.  If the investigator's causality assessment is “unknown but not 
related” to investigational product, this should be clearly documented on study records. 
In addition, if the investigator determines that an SAE is associated with study procedures 
and/or concomitant medications or therapies, the investigator must record this causal 
relationship in the source documents and CRF, and report such an assessment in the 
dedicated section of the CT SAE Report Form and in accordance with the SAE reporting 
requirements.
8.1.6. Sponsor’s Reporting Requirements to Regulatory Authorities
AE reporting, including suspected unexpected serious adverse reactions, will be carried out 
in accordance with applicable local regulations.
8.2. Definitions
8.2.1. Adverse Events
An AE is any untoward medical occurrence in a study subject administered a product or 
medical device; the event need not necessarily have a causal relationship with the treatment 
or usage.  Examples of AEs include, but are not limited to: 

Abnormal test findings;

Clinically significant signs and symptoms;

Changes in physical examination findings;

Hypersensitivity;

Progression/worsening of underlying disease;

Drug abuse;

Drug dependency.

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Additionally, AEs may include signs and symptoms resulting from:

Drug overdose;

Drug withdrawal;

Drug misuse;

Drug interactions;

Extravasation;

Exposure during pregnancy (EDP);

Exposure via breastfeeding;

Medication error;

Occupational exposure.
8.2.2. Abnormal Test Findings
Abnormal objective test findings should be recorded as AEs when any of the following 
conditions are met: 

Test result is associated with accompanying symptoms; and/or

Test result requires additional diagnostic testing or medical/surgical intervention; 
and/or

Test result leads to a change in study dosing (outside of any protocol-specified dose 
adjustments) or discontinuation from the study, significant additional concomitant 
drug treatment, or other therapy; and/or

Test result is considered to be an AE by the investigator or sponsor.
Merely repeating an abnormal test, in the absence of any of the above conditions, does not 
constitute an AE.  Any abnormal test result that is determined to be an error does not require 
recording as an AE.
8.2.3. Serious Adverse Events
A serious adverse event is any untoward medical occurrence at any dose that:

Results in death;

Is life-threatening (immediate risk of death);

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
Requires inpatient hospitalization or prolongation of existing hospitalization;

Results in persistent or significant disability/incapacity (substantial disruption of the 
ability to conduct normal life functions);

Results in congenital anomaly/birth defect.
Or that is considered to be:

An important medical event.
Medical and scientific judgment is exercised in determining whether an event is an important 
medical event.  An important medical event may not be immediately life-threatening and/or 
result in death or hospitalization.  However, if it is determined that the event may jeopardize 
the subject or may require intervention to prevent one of the other AE outcomes, the 
important medical event should be reported as serious.
Examples of such events are intensive treatment in an emergency room or at home for 
allergic bronchospasm; blood dyscrasias or convulsions that do not result in hospitalization; 
or development of drug dependency or drug abuse.
8.2.4. Hospitalization
Hospitalization is defined as any initial admission (even less than 24 hours) in a hospital or 
equivalent healthcare facility, or any prolongation of an existing admission.  Admission also 
includes transfer within the hospital to an acute/intensive care unit (eg, from the psychiatric 
wing to a medical floor, medical floor to a coronary care unit, or neurological floor to a 
tuberculosis unit).  An emergency room visit does not necessarily constitute a hospitalization; 
however, the event leading to the emergency room visit is assessed for medical importance.
Hospitalization does not include the following:

Rehabilitation facilities;

Hospice facilities;

Respite care (eg, caregiver relief);

Skilled nursing facilities;

Nursing homes;

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Hospitalization or prolongation of hospitalization in the absence of a precipitating clinical 
AE is not in itself an SAE.  Examples include:

Admission for treatment of a preexisting condition not associated with the 
development of a new AE or with a worsening of the preexisting condition (eg, for 
workup of a persistent pretreatment laboratory abnormality);

Social admission (eg, subject has no place to sleep);

Administrative admission (eg, for yearly physical examination);

Protocol-specified admission during a study (eg, for a procedure required by the study 
protocol);

Optional admission not associated with a precipitating clinical AE (eg, for elective 
cosmetic surgery);

Hospitalization for observation without a medical AE;

Preplanned treatments or surgical procedures.  These should be noted in the baseline 
documentation for the entire protocol and/or for the individual subject.
Diagnostic and therapeutic noninvasive and invasive procedures, such as surgery, should not 
be reported as SAEs.  However, the medical condition for which the procedure was 
performed should be reported if it meets the definition of an SAE.  For example, an acute 
appendicitis that begins during the reporting period should be reported if the SAE 
requirements are met, and the resulting appendectomy should be recorded as treatment of the 
AE.
8.3. Severity Assessment
If required on the AE page of the CRF, the investigator will use the adjectives MILD, 
MODERATE, or SEVERE to describe the maximum intensity of the AE.  For purposes 
of consistency, these intensity grades are defined as follows:
MILD
Does not interfere with subject's usual function.
MODERATE
Interferes to some extent with subject's usual function.
SEVERE
Interferes significantly with subject's usual function.
Note the distinction between the severity and the seriousness of an AE.  A severe event is not 
necessarily an SAE.  For example, a headache may be severe (interferes significantly with 
the subject's usual function) but would not be classified as serious unless it met one of the 
criteria for SAEs, listed above.

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8.4. Special Situations
8.4.1. Protocol-Specified Serious Adverse Events
Unless the investigator believes that there is a causal relationship between the investigational 
product and an event specified below, these events should not be reported to Pfizer Safety by 
the investigator as SAEs.  These events are anticipated to occur commonly in a population 
with DMD.  However, these events should still be recorded as AEs on the CRF.
Protocol-specified SAEs that will not normally be reported to Pfizer Safety in an expedited 
manner: 
1. Loss of mobility or ambulation;
2. Muscle weakness;
3. Symptoms related to spinal deformity;
4. Respiratory muscle weakness/Hypoxia;
5. Fracture;
6. Steroid related metabolic changes (eg, hypertension, diabetes).
Should an aggregate analysis indicate that these pre-specified events occur more frequently 
than expected, eg, based on epidemiological data, literature, or other data, then this will be 
submitted and reported in accordance with Pfizer’s safety reporting requirements.  Aggregate 
analyses of safety data will be performed on a regular basis per internal standard operating 
procedures.
8.4.2. Potential Cases of Drug-Induced Liver Injury
Humans exposed to a drug who show no sign of liver injury (as determined by elevations in 
transaminases) are termed “tolerators,” while those who show transient liver injury, but adapt 
are termed “adaptors.”  In some subjects, transaminase elevations are a harbinger of a more 
serious potential outcome.  These subjects fail to adapt and therefore are "susceptible" to 
progressive and serious liver injury, commonly referred to as drug-induced liver injury 
(DILI).
In the majority of DILI cases, elevations in aspartate aminotransferase (AST) and/or alanine 
aminotransferase (ALT) precede total bilirubin (TBili) elevations (>2 × ULN) by several 
days or weeks.  The increase in TBili typically occurs while AST/ALT is/are still elevated 
above 3 × ULN (ie, AST/ALT and TBili values will be elevated within the same lab sample).  
In rare instances, by the time TBili elevations are detected, AST/ALT values might have 
decreased.  This occurrence is still regarded as a potential DILI.  Therefore, abnormal 
elevations in either AST OR ALT in addition to TBili that meet the criteria outlined below 
are considered potential DILI (assessed per Hy’s law criteria) cases and should always be 
considered important medical events, even before all other possible causes of liver injury 
have been excluded.

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The threshold of laboratory abnormalities for a potential DILI case depends on the subject’s 
individual baseline values and underlying conditions.  Subjects who present with the 
following laboratory abnormalities should be evaluated further as potential DILI (Hy’s law) 
cases to definitively determine the etiology of the abnormal laboratory values:

Subjects with AST/ALT and TBili baseline values within the normal range who 
subsequently present with AST OR ALT values >3 × ULN AND a TBili value 
>2 × ULN with no evidence of hemolysis and an alkaline phosphatase value 
<2 × ULN or not available.

For subjects with baseline AST OR ALT OR TBili values above the ULN, the 
following threshold values are used in the definition mentioned above, as needed, 
depending on which values are above the ULN at baseline:

Preexisting AST or ALT baseline values above the normal range: AST or ALT 
values >2 times the baseline values AND >3 × ULN; or >8 × ULN (whichever is 
smaller).

Preexisting values of TBili above the normal range: TBili level increased from 
baseline value by an amount of at least 1 × ULN or if the value reaches 
>3 × ULN (whichever is smaller).
Rises in AST/ALT and TBili separated by more than a few weeks should be assessed 
individually based on clinical judgment; any case where uncertainty remains as to whether it 
represents a potential Hy’s law case should be reviewed with the sponsor. 
In addition, however, as described in Section 1.5.1, in DMD patients, the standard 
biomarkers of the onset of hepatocellular injury such as ALT and AST are not capable of 
detection of liver damage due to the release of these enzymes from diseased skeletal muscle.  
To address the shortcoming, elevations of GLDH >2 x ULN will also be assessed 
individually based on clinical judgment and with the support of the ad hoc hepatic and/or 
immunopharmacologic expert (s) supporting the E-DMC; any case where uncertainty 
remains as to whether it represents a potential Hy’s law case should be reviewed with the 
sponsor.  Subjects who experience a consistent GLDH elevation above 3 × ULN may also be 
monitored more frequently to determine if they are an “adaptor” or are “susceptible”, as 
defined above.
If any of the above criteria is met, the subject should return to the investigator site and be 
evaluated as soon as possible, preferably within 48 hours from awareness of the abnormal 
results.  This evaluation should include laboratory tests, detailed history, and physical 
assessment. 
In addition to repeating measurements of AST and ALT and TBili, laboratory tests should 
include albumin, creatine kinase (CK), direct and indirect bilirubin, gamma-glutamyl 
transferase (GGT), GLDH, prothrombin time (PT)/international normalized ratio (INR), total 
bile acids, alkaline phosphatase and acetaminophen drug and/or protein adduct levels.  

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Consideration should also be given to drawing a separate tube of clotted blood and an 
anticoagulated tube of blood for further testing, as needed, for further contemporaneous 
analyses at the time of the recognized initial abnormalities to determine etiology.  A detailed 
history, including relevant information, such as review of ethanol, acetaminophen (either by 
itself or as a co-formulated product in prescription or over-the-counter medications), 
recreational drug, supplement (herbal) use and consumption, family history, sexual history, 
travel history, history of contact with a jaundiced person, surgery, blood transfusion, history 
of liver or allergic disease, and potential occupational exposure to chemicals, should be 
collected.  Further testing for acute hepatitis A, B, C, D, and E infection and liver imaging 
(eg, biliary tract) may be warranted. 
All cases demonstrated on repeat testing as meeting the laboratory criteria of AST/ALT and 
TBili elevation defined above should be considered potential DILI (Hy’s law) cases if no 
other reason for the liver function test (LFT) abnormalities has yet been found.  Such 
potential DILI (Hy’s law) cases are to be reported as SAEs, irrespective of availability 
of all the results of the investigations performed to determine etiology of the LFT 
abnormalities.
A potential DILI (Hy’s law) case becomes a confirmed case only after all results of 
reasonable investigations have been received and have excluded an alternative etiology.
8.4.3. Exposure to the Investigational Product during Pregnancy or Breastfeeding, and 
Occupational Exposure
Exposure to the investigational product under study during pregnancy or breastfeeding and 
occupational exposure are reportable to Pfizer Safety within 24 hours of investigator 
awareness.
8.4.3.1. Exposure during Pregnancy
For both unapproved/unlicensed products and for marketed products, an exposure during 
pregnancy (EDP) occurs if:

A female becomes, or is found to be, pregnant either while receiving or having been 
exposed (eg, because of treatment or environmental exposure) to the investigational 
product; or the female becomes or is found to be pregnant after discontinuing and/or 
being exposed to the investigational product:

An example of environmental exposure would be a case involving direct contact 
with a Pfizer product in a pregnant woman (eg, a nurse reports that she is pregnant 
and has been exposed to chemotherapeutic products).

A male has been exposed (eg, because of treatment or environmental exposure) to the 
investigational product prior to or around the time of conception and/or is exposed 
during his partner’s pregnancy. 

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
A male family member or healthcare provider who has been exposed to the study 
intervention by skin, mucosal contact, or ingestion then exposes his female partner 
prior to or around the time of conception.

A female household member of a study subject reports that she is pregnant and has 
been exposed through viral shedding by a study subject within 2 months after dosing, 
and a month prior to or during pregnancy.
If a subject or subject’s partner becomes or is found to be pregnant during the subject’s 
treatment with the investigational product, the investigator must report this information to 
Pfizer Safety on the CT SAE Report Form and an EDP supplemental form, regardless of 
whether an SAE has occurred.  In addition, the investigator must submit information 
regarding environmental exposure to a Pfizer product in a pregnant woman (eg, a subject 
reports that she is pregnant and has been exposed to a cytotoxic product by inhalation or 
spillage) to Pfizer Safety using the EDP supplemental form.  This must be done irrespective 
of whether an AE has occurred and within 24 hours of awareness of the exposure.  The 
information submitted should include the anticipated date of delivery (see below for 
information related to termination of pregnancy).
Follow-up is conducted to obtain general information on the pregnancy and its outcome for 
all EDP reports with an unknown outcome.  The investigator will follow the pregnancy until 
completion (or until pregnancy termination) and notify Pfizer Safety of the outcome as a 
follow-up to the initial EDP supplemental form.  In the case of a live birth, the structural 
integrity of the neonate can be assessed at the time of birth.  In the event of a termination, the 
reason(s) for termination should be specified and, if clinically possible, the structural 
integrity of the terminated fetus should be assessed by gross visual inspection (unless 
pre-procedure test findings are conclusive for a congenital anomaly and the findings are 
reported).
If the outcome of the pregnancy meets the criteria for an SAE (ie, ectopic pregnancy, 
spontaneous abortion, intrauterine fetal demise, neonatal death, or congenital anomaly [in a 
live-born baby, a terminated fetus, an intrauterine fetal demise, or a neonatal death]), the 
investigator should follow the procedures for reporting SAEs.
Additional information about pregnancy outcomes that are reported to Pfizer Safety as SAEs 
follows: 

Spontaneous abortion includes miscarriage and missed abortion;

Neonatal deaths that occur within 1 month of birth should be reported, without regard 
to causality, as SAEs.  In addition, infant deaths after 1 month should be reported as 
SAEs when the investigator assesses the infant death as related or possibly related to 
exposure to the investigational product.
Additional information regarding the EDP may be requested by the sponsor.  Further 
follow-up of birth outcomes will be handled on a case-by-case basis (eg, follow-up on 
preterm infants to identify developmental delays).  In the case of paternal exposure, the 
investigator will provide the subject with the Pregnant Partner Release of Information Form 

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to deliver to his partner.  The investigator must document in the source documents that the 
subject was given the Pregnant Partner Release of Information Form to provide to his 
partner.
8.4.3.2. Exposure during Breastfeeding
Scenarios of exposure during breastfeeding must be reported, irrespective of the presence of 
an associated SAE, to Pfizer Safety within 24 hours of the investigator’s awareness, using the 
CT SAE Report Form.  An exposure during breastfeeding report is not created when a Pfizer 
drug specifically approved for use in breastfeeding women (eg, vitamins) is administered in 
accord with authorized use.  However, if the infant experiences an SAE associated with such 
a drug’s administration, the SAE is reported together with the exposure during breastfeeding.
8.4.3.3. Occupational Exposure
An occupational exposure occurs when, during the performance of job duties, a person 
(whether a healthcare professional or otherwise) gets in unplanned direct contact with the 
product, which may or may not lead to the occurrence of an AE.
An occupational exposure is reported to Pfizer Safety within 24 hours of the investigator’s 
awareness, using the CT SAE Report Form, regardless of whether there is an associated 
SAE.  Since the information does not pertain to a subject enrolled in the study, the 
information is not recorded on a CRF; however, a copy of the completed CT SAE Report 
Form is maintained in the investigator site file.
8.4.4. Medication Errors 
Other exposures to the investigational product under study may occur in clinical trial settings, 
such as medication errors.
Safety Event
Recorded on the CRF
Reported on the CT SAE 
Report Form to Pfizer Safety 
Within 24 Hours of Awareness
Medication errors 
All (regardless of whether 
associated with an AE)
Only if associated with an SAE
Medication errors may result from the administration or consumption of the investigational 
product by the wrong subject, or at the wrong time, or at the wrong dosage strength. 
Medication errors include:

Medication errors involving subject exposure to the investigational product;

Potential medication errors or uses outside of what is foreseen in the protocol that do 
or do not involve the participating subject;

Administration of the incorrect dose level.
Such medication errors occurring to a study subject are to be captured on the medication 
error page of the CRF, which is a specific version of the AE page.

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In the event of a medication dosing error, the sponsor should be notified immediately.
Whether or not the medication error is accompanied by an AE, as determined by the 
investigator, the medication error is recorded on the medication error page of the CRF and, if 
applicable, any associated AE(s), serious and non-serious, are recorded on an AE page of the 
CRF.
Medication errors should be reported to Pfizer Safety within 24 hours on a CT SAE Report 
Form only when associated with an SAE.
9. DATA ANALYSIS/STATISTICAL METHODS
Detailed methodology for summary and statistical analyses of the data collected in this study 
is outlined here and further detailed in a statistical analysis plan (SAP), which will be 
maintained by the sponsor.  The SAP may modify what is outlined in the protocol where 
appropriate; however, any major modifications of the primary endpoint definitions or their 
analyses will also be reflected in a protocol amendment.
9.1. Sample Size Determination
The total sample size of up to 22 subjects across 2 dose cohorts, of 2 sub-populations 
(ambulatory and non-ambulatory) and the sirolimus cohort is based on clinical considerations 
to provide adequate safety, tolerability, and pharmacodynamics (PD) information at each 
dose level for both ambulatory and non-ambulatory subjects. 
9.2. Safety Analysis
Adverse events, ECGs, vital signs (blood pressure and heart rate), physical & neurological 
examinations, cardiac MRI (or echocardiogram) and safety laboratory data (including 
hematology, chemistry and urinalysis) will be reviewed and summarized on an ongoing basis 
during the study to evaluate the safety of subjects.  Safety data will be presented in tabular 
and/or graphical format and summarized descriptively, where appropriate.  Incidence and 
severity of TEAEs, withdrawals due to TEAEs, and infusion and injection site reactions will 
be summarized by dose level and ambulatory status at baseline.  Abnormal and clinically 
relevant changes in physical and neurological examinations, height and weight, vital signs, 
cardiac MRI (or echocardiogram) and ECG parameters will be summarized by dose level, 
ambulatory status at baseline, and study day.  Incidence and magnitude of abnormal 
laboratory findings will be summarized by dose level and ambulatory status at baseline. 
Medical history and medication history, as applicable, collected during the course of the 
study will be captured for inclusion into the study database, unless otherwise noted.  Any 
untoward findings identified on physical examination conducted after the administration of 
the investigational product will be captured as an adverse event, if those findings meet the 
definition of an adverse event.  Data collected at Screening that are used for 
inclusion/exclusion criteria, such as laboratory data, ECGs and vital signs will be included in 
the study database.  Demographic data collected at Screening will be reported.

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Primary safety analyses will be based on the data through 1-year post treatment.  Secondary 
safety analyses will be based on the long-term follow up data through 5-years post treatment. 
9.2.1. Derivation of Vital Signs Parameters
Blood pressures and heart rate will be recorded at each assessment time indicated in the 
Schedule of Activities.  Baseline for vital signs will be defined as the last measurement 
before the Day 1 investigational product administration.
Vital signs (BP; HR) will be assessed for clinically relevant trends.  The standard algorithms 
and reporting formats will be applied for analyzing all safety data. 
Absolute values and changes from baseline for systolic and diastolic blood pressure and heart 
rate will be summarized by dose level, ambulatory status at baseline and study visit.
Maximum absolute values and maximum changes from baseline for vital signs will also be 
summarized descriptively by dose level and ambulatory status at baseline using categories as 
defined in the SAP.  Numbers and percentages of subjects meeting the categorical criteria 
will be provided and individual values listed in the study report.
9.2.2. Electrocardiogram (ECG) Analysis 
Baseline for ECG will be defined as the measurement before the Day 1 study drug 
administration.  Changes from baseline for the ECG parameters QT interval, pulse rate, 
QTcF interval, PR interval and QRS interval will be summarized by dose level, ambulatory 
status at baseline, and study visit.
The number (%) of subjects with maximum post dose QTc values and maximum increases 
from baseline in the following categories will be tabulated by dose level and ambulatory 
status at baseline: 
Safety QTcF
Borderline (msec)
Prolonged (msec)
Absolute Value
≥450 - <480
≥480
Absolute Change
30 - <60
≥60
In addition, the number of subjects with corrected and uncorrected QT values ≥500 msec
will be summarized.
If more than one ECG is collected at a nominal time post dose (for example, triplicate 
ECGs), the mean of the replicate measurements will be used to represent a single observation 
at that time point.  If any of the three individual ECG tracings has a QTcF value ≥500 msec, 
but the mean of the triplicates is not ≥500 msec, the data from the subject’s individual 
tracing will be described in a safety section of the study report in order to place the ≥
500 msec value in appropriate clinical context.  However, values from individual tracings 
within triplicate measurements that are ≥500 msec will not be included in the categorical 

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analysis unless the average from the triplicate measurements is also Ŏ500 msec.  Changes 
from baseline will be defined as the change between QTcF post dose from the average of the 
last pre-dose triplicate values on the dosing day in each period.
 
 
9.3. Analysis of Secondary Pharmacodynamic Endpoints
The level of mini-dystrophin expression in muscle biopsies will be assessed by Western blot 
and/or LC-MS and its distribution by immunofluorescence.  Details regarding the analysis 
will be included in the statistical analysis plan (SAP).
 
 
 
 
 
  
 
 
 
9.5. Interim Analysis
No formal interim analysis (IA) will be conducted for this study.  However, as this is an 
open-label study, the sponsor and E-DMC may conduct unblinded reviews of the data during 
the course of the study for the purpose of safety assessment, facilitating dose escalation 
decisions, and/or to support clinical development.  Primary safety analyses and analyses of 
mini-dystrophin expression and transduction, functional assessments, NAb and ELISpot, 
viral vector shedding, and health-related outcome measures will occur after the respective 
study population (ambulatory, non-ambulatory) completes the 1st Year of Follow-up. 
9.6. Data Monitoring Committee 
The study will utilize an independent E-DMC according to the charter.  Members of the 
E-DMC will not be Pfizer employees, but may include experts in the field of neurology, 
immunopharmacology, hepatology, complement activation, AAV vectors, and/or statistics.  
The E-DMC may also include a cardiologist to provide expert interpretation of cardiac MRI 
(or echocardiogram).  A patient advocate will also be included on the E-DMC if an 
appropriately qualified individual can be identified as agreed upon by the E-DMC 
chairperson. 
CCI
CCI

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The E-DMC will be responsible for ongoing monitoring of the safety as well as benefit/risk 
profile of subjects in the study.  Reviews will include aggregate safety, targeted medical 
events of special interest, and serious AE data.  The E-DMC may also complete ad hoc safety 
reviews of cohort data and/or individual subject data as requested by the sponsor study team 
as described in the E-DMC charter. 
Following each data review, the E-DMC will provide a data-driven recommendation to the 
sponsor management to continue the study, modify the study and then continue 
(eg, terminate a dose level or de-escalate to a lower dose), or stop the study (eg, due to 
safety).  The recommendations made by the E-DMC to alter the conduct of the study will be 
forwarded to Pfizer for final decision.  Pfizer will forward such decisions, which may include 
summaries of aggregate analyses of endpoint events and of safety data that are not endpoints, 
to regulatory authorities, as appropriate.  At any time, the E-DMC may indicate that the limit 
of safety and/or tolerability has been reached and that any of the dose levels will be removed 
from the study or adjusted.
Additional specifics regarding E-DMC responsibilities, inclusive of decisions around dose 
progression, are detailed in Section 3.5.
10. QUALITY CONTROL AND QUALITY ASSURANCE
Pfizer or its agent will conduct periodic monitoring visits during study conduct to ensure that 
the protocol and Good Clinical Practices (GCPs) are being followed.  The monitors may 
review source documents to confirm that the data recorded on CRFs are accurate.  The 
investigator and institution will allow Pfizer monitors/auditors or its agents and appropriate 
regulatory authorities direct access to source documents to perform this verification.  This 
verification may also occur after study completion.
During study conduct and/or after study completion, the investigator site may be subject to 
review by the IRB/EC, and/or to quality assurance audits performed by Pfizer, or companies 
working with or on behalf of Pfizer, and/or to inspection by appropriate regulatory 
authorities.
The investigator(s) will notify Pfizer or its agents immediately of any regulatory inspection 
notification in relation to the study.  Furthermore, the investigator will cooperate with Pfizer 
or its agents to prepare the investigator site for the inspection and will allow Pfizer or its 
agent, whenever feasible, to be present during the inspection.  The investigator site and 
investigator will promptly resolve any discrepancies that are identified between the study 
data and the subject's medical records.  The investigator will promptly provide copies of the 
inspection findings to Pfizer or its agent.  Before response submission to the regulatory 
authorities, the investigator will provide Pfizer or its agents with an opportunity to review 
and comment on responses to any such findings.
It is important that the investigator(s) and their relevant personnel are available during the 
monitoring visits and possible audits or inspections and that sufficient time is devoted to the 
process.

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11. DATA HANDLING AND RECORD KEEPING
11.1. Case Report Forms/Electronic Data Record
As used in this protocol, the term CRF should be understood to refer to either a paper form or 
an electronic data record or both, depending on the data collection method used in this study.
A CRF is required and should be completed for each included subject.  The completed 
original CRFs are the sole property of Pfizer and should not be made available in any form to 
third parties, except for authorized representatives of Pfizer or appropriate regulatory 
authorities, without written permission from Pfizer.
The investigator has ultimate responsibility for the collection and reporting of all clinical, 
safety, and laboratory data entered on the CRFs and any other data collection forms (source 
documents) and ensuring that they are accurate, authentic/original, attributable, complete, 
consistent, legible, timely (contemporaneous), enduring, and available when required.  The 
CRFs must be signed by the investigator or by an authorized staff member to attest that the 
data contained on the CRFs are true.  Any corrections to entries made in the CRFs or source 
documents must be dated, initialed, and explained (if necessary) and should not obscure the 
original entry. 
In most cases, the source documents are the hospital or the physician subject chart.  In these 
cases, data collected on the CRFs must match the data in those charts. 
In some cases, the CRF may also serve as the source document.  In these cases, a document 
should be available at the investigator site and at Pfizer that clearly identifies those data that 
will be recorded on the CRF, and for which the CRF will stand as the source document.
11.2. Record Retention
To enable evaluations and/or inspections/audits from regulatory authorities or Pfizer, the 
investigator agrees to keep records, including the identity of all participating subjects 
(sufficient information to link records, eg, CRFs and hospital records), all original signed 
informed consent/assent documents, copies of all CRFs, safety reporting forms, source 
documents, and detailed records of treatment disposition, and adequate documentation of 
relevant correspondence (eg, letters, meeting minutes, and telephone call reports).  The 
records should be retained by the investigator according to the ICH guidelines, according to 
local regulations, or as specified in the clinical study agreement (CSA), whichever is longer.
If the investigator becomes unable for any reason to continue to retain study records for the 
required period (eg, retirement, relocation), Pfizer should be prospectively notified.  The 
study records must be transferred to a designee acceptable to Pfizer, such as another 
investigator, another institution, or an independent third party arranged by Pfizer. 
Investigator records must be kept for a minimum of 15 years after completion or 
discontinuation of the study or for longer if required by applicable local regulations. 

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The investigator must obtain Pfizer's written permission before disposing of any records, 
even if retention requirements have been met.
12. ETHICS
12.1. Institutional Review Board/Ethics Committee
It is the responsibility of the investigator to have prospective approval of the study protocol, 
protocol amendments, informed consent/assent documents, and other relevant documents, 
eg, recruitment advertisements, if applicable, from the IRB/EC.  All correspondence with the 
IRB/EC should be retained in the investigator file.  Copies of IRB/EC approvals should be 
forwarded to Pfizer.
The only circumstance in which an amendment may be initiated prior to IRB/EC approval is 
where the change is necessary to eliminate apparent immediate hazards to the subjects.  In 
that event, the investigator must notify the IRB/EC and Pfizer in writing immediately after 
the implementation.
12.2. Ethical Conduct of the Study
The study will be conducted in accordance with the protocol, legal and regulatory 
requirements and the general principles set forth in the International Ethical Guidelines for 
Biomedical Research Involving Human Subjects (Council for International Organizations of 
Medical Sciences 2002), ICH Guideline for Good Clinical Practice, and the Declaration of 
Helsinki.
12.3. Subject Information and Consent
All parties will ensure protection of subject personal data and will not include subject names 
or other identifiable data in any reports, publications, or other disclosures, except where 
required by law. 
When study data are compiled for transfer to Pfizer and other authorized parties, subject 
names, addresses, and other identifiable data will be replaced by numerical codes based on a 
numbering system provided by Pfizer in order to de-identify study subjects.  The investigator 
site will maintain a confidential list of subjects who participated in the study, linking each 
subject’s numerical code to his or her actual identity.  In case of data transfer, Pfizer will 
maintain high standards of confidentiality and protection of subjects’ personal data consistent 
with applicable privacy laws.
The informed consent/assent documents and any subject recruitment materials must be in 
compliance with ICH GCP, local regulatory requirements, and legal requirements, including 
applicable privacy laws.
The informed consent/assent documents used during the informed consent process and any 
subject recruitment materials must be reviewed and approved by Pfizer, approved by the 
IRB/EC before use, and available for inspection.

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The investigator must ensure that each study subject, or his or her legally acceptable 
representative, or parent(s) or legal guardian if a minor, is fully informed about the nature 
and objectives of the study and possible risks associated with participation. 
Whenever consent is obtained from a subject’s legally acceptable representative/parent(s) or 
legal guardian, the subject’s assent (affirmative agreement) must subsequently be obtained 
when the subject has the capacity to provide assent, as determined by the IRB/EC.  If the 
investigator determines that a subject’s decisional capacity is so limited he/she cannot 
reasonably be consulted, then, as permitted by the IRB/EC and consistent with local 
regulatory and legal requirements, the subject’s assent may be waived with source 
documentation of the reason assent was not obtained.  If the study subject does not provide 
his or her own consent, the source documents must record why the subject did not provide 
consent (eg, minor, decisionally impaired adult), how the investigator determined that the 
person signing the consent was the subject’s legally acceptable representative, the consent 
signer’s relationship to the study subject (eg, parent, spouse), and that the subject’s assent 
was obtained or waived.  If assent is obtained verbally, it must be documented in the source 
documents.
If the study includes minor subjects who reach the age of majority during the study, as 
recognized under local law, they must re-consent as adults to remain in the study.  If the 
enrollment of emancipated minors is permitted by the study age criteria, the IRB/EC, and 
local law, they must provide documentation of legal status to give consent without the 
permission of a parent(s) or legal guardian. 
The investigator, or a person designated by the investigator, will obtain written informed 
consent from each subject or the subject's legally acceptable representative, parent(s) or legal 
guardian and the subject’s assent, when applicable, before any study-specific activity is 
performed, unless a waiver of informed consent has been granted by an IRB/EC.  The 
investigator will retain the original of each subject's signed consent/assent document.
12.4. Reporting of Safety Issues and Serious Breaches of the Protocol or ICH GCP
In the event of any prohibition or restriction imposed (ie, clinical hold) by an applicable 
regulatory authority in any area of the world, or if the investigator is aware of any new 
information that might influence the evaluation of the benefits and risks of the investigational 
product, Pfizer should be informed immediately. 
In addition, the investigator will inform Pfizer immediately of any urgent safety measures 
taken by the investigator to protect the study subjects against any immediate hazard, and of 
any serious breaches of this protocol or of ICH GCP that the investigator becomes aware of.
13. DEFINITION OF END OF TRIAL
13.1. End of Trial 
The end of trial for the study is defined as the last subject last visit (LSLV).

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14. SPONSOR DISCONTINUATION CRITERIA
Premature termination of this study may occur because of a regulatory authority decision, 
change in opinion of the IRB/EC, or investigational product safety problems, or at the 
discretion of Pfizer.  In addition, Pfizer retains the right to discontinue development of 
PF-06939926 at any time.
If a study is prematurely terminated, Pfizer will promptly notify the investigators.  After 
notification, the investigators must contact all participating subjects and the site pharmacy (if 
applicable) within 1 (one) week.  As directed by Pfizer, all study materials must be collected 
and all CRFs completed to the greatest extent possible.
15. PUBLICATION OF STUDY RESULTS
15.1. Communication of Results by Pfizer
Pfizer fulfills its commitment to publicly disclose clinical trial results through posting the 
results of studies on www.clinicaltrials.gov (ClinicalTrials.gov), the European Clinical Trials 
Database (EudraCT), and/or www.pfizer.com, and other public registries in accordance with 
applicable local laws/regulations. 
In all cases, study results are reported by Pfizer in an objective, accurate, balanced, and 
complete manner and are reported regardless of the outcome of the study or the country in 
which the study was conducted.
www.clinicaltrials.gov
Pfizer posts clinical trial US Basic Results on www.clinicaltrials.gov for Pfizer-sponsored 
interventional studies (conducted in patients) that evaluate the safety and/or efficacy of a 
Pfizer product, regardless of the geographical location in which the study is conducted.  US 
Basic Results are submitted for posting within 1 year of the primary completion date (PCD) 
for studies in adult populations or within 6 months of the PCD for studies in pediatric 
populations.
PCD is defined as the date that the final subject was examined or received an intervention for 
the purposes of final collection of data for the primary outcome, whether the clinical study 
concluded according to the prespecified protocol or was terminated.
EudraCT
Pfizer posts European Union (EU) Basic Results on EudraCT for all Pfizer-sponsored 
interventional studies that are in scope of EU requirements.  EU Basic Results are submitted 
for posting within 1 year of the PCD for studies in adult populations or within 6 months of 
the PCD for studies in pediatric populations.

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www.pfizer.com
Pfizer posts Public Disclosure Synopses (clinical study report synopses in which any data 
that could be used to identify individual patients has been removed) on www.pfizer.com for 
Pfizer-sponsored interventional studies at the same time the US Basic Results document is 
posted to www.clinicaltrials.gov.
15.2. Publications by Investigators
Pfizer supports the exercise of academic freedom and has no objection to publication by the 
principal investigator (PI) of the results of the study based on information collected or 
generated by the PI, whether or not the results are favorable to the Pfizer product.  However, 
to ensure against inadvertent disclosure of confidential information or unprotected 
inventions, the investigator will provide Pfizer an opportunity to review any proposed 
publication or other type of disclosure of the results of the study (collectively, “publication”) 
before it is submitted or otherwise disclosed.
The investigator will provide any publication to Pfizer at least 30 days before it is submitted 
for publication or otherwise disclosed.  If any patent action is required to protect intellectual 
property rights, the investigator agrees to delay the disclosure for a period not to exceed an 
additional 60 days.
The investigator will, on request, remove any previously undisclosed confidential 
information before disclosure, except for any study- or Pfizer product-related information 
necessary to the appropriate scientific presentation or understanding of the study results.
If the study is part of a multicenter study, the investigator agrees that the first publication is 
to be a joint publication covering all investigator sites, and that any subsequent publications 
by the principal investigator (PI) will reference that primary publication.  However, if a joint 
manuscript has not been submitted for publication within 12 months of completion or 
termination of the study at all participating sites, the investigator is free to publish separately, 
subject to the other requirements of this section.
For all publications relating to the study, the institution will comply with recognized ethical 
standards concerning publications and authorship, including Section II - “Ethical 
Considerations in the Conduct and Reporting of Research” of the Uniform Requirements for 
Manuscripts Submitted to Biomedical Journals, http://www.icmje.org/index.html#authorship, 
established by the International Committee of Medical Journal Editors.
Publication of study results is also provided for in the CSA between Pfizer and the 
institution.  In this section entitled Publications by Investigators, the defined terms shall have 
the meanings given to them in the CSA.
If there is any conflict between the CSA and any attachments to it, the terms of the CSA 
control.  If there is any conflict between this protocol and the CSA, this protocol will control 
as to any issue regarding treatment of study subjects, and the CSA will control as to all other 
issues.

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Bushby K, Finkel R, Birnkrant DJ, et al. Diagnosis and management of Duchenne 
muscular dystrophy, part 1: diagnosis, and pharmacological and psychosocial 
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Yu X, Bao B, Echigoya Y, et al. Dystrophin-deficient large animal models: translational 
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Hendriksen RG, Hoogland G, Schipper S, et al. A possible role of dystrophin in 
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Henricson EK, Abresch RT, Cnaan A, et al. The cooperative international 
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progression as measured by manual muscle testing and other commonly used clinical 
trial outcome measures. Muscle Nerve 2013; 48(1)(Jul):55-67.
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Aartsma-Rus A, Fokkema I, Verschuuren J, et al. Theoretic applicability of antisense-
mediated exon skipping for Duchenne muscular dystrophy mutations. Hum Mutat 2009; 
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Appendix 1. Cohort to Assess the Effect of Sirolimus on Complement Activation 
Related to PF-06939926 Infusion
Rationale:  
An immune response to the viral vector following PF-06939926 infusion has been observed 
to activate complement and may lead to complement-related SAEs.  A hallmark of this 
immune response is the consistent pattern of decreased platelets and decreased C4 which has 
been observed within 14 days after infusion with PF-06939926.  Sirolimus (Rapamune) 
prevents B-cell activation69,70 and has been demonstrated to inhibit anti-AAV9 neutralizing 
antibody production in non-human primates and to inhibit antibody formation and 
complement activation after gene therapy in patients with GM1 gangliosidosis (Salabarria et 
al., 2021 presentation at MDA).    
The purpose of this cohort is to evaluate the effect of sirolimus on the measured platelet and 
C4 levels and NAb antibody titers after infusion of PF-06939926 to determine if sirolimus 
might serve as an added mitigation strategy to reduce the risk of complement-related SAEs 
following PF-06939926 infusion. 
Dose Rationale:
For subjects weighing ≤40 kg, sirolimus loading dose of 2.25 mg/m2 BSA twice daily will be 
administered on Day -10 prior to PF-06939926 infusion, followed by maintenance dose of 
0.75 mg/m2 BSA twice daily.  For subjects weighing >40 kg, sirolimus loading dose of 3 mg 
twice daily will be administered on Day -10 prior to PF-06939926 infusion, followed by 
twice daily maintenance Dose of 1 mg.  The maintenance doses in both the cases will be 
adjusted to achieve sirolimus trough concentrations within the target range.  Please refer to 
Cohort Intervention table for detailed instructions on the dose, dosing regimen, and 
maintenance dose adjustments. 
The doses were chosen to achieve sirolimus target trough concentration between 4.0 and 
7.0 ng/mL in DMD boys.  The target levels are lower than those considered for initial 
treatment of renal transplant patients (pivotal studies included levels >10 ng/mL for the first 
year, and now with more typical target ranges of 6-12 ng/mL during the first 6 months), as 
the goal of sirolimus dose in this study is to suppress the humoral immune response in the 
initial post-treatment period when the AAV viral vector levels are high.  To determine a 
lower, effective dose, a non-clinical study in cynomolugus monkeys was performed.  In this 
study, following administration of AAV9, low dose sirolimus trough levels (<3 ng/mL) were 
ineffective in suppressing the rise of NAb, whereas higher dose trough levels (~3-4 ng/mL) 
were effective.  Given the variability among subjects’ trough levels at a given dose, the target 
trough range was extended up to 7 ng/mL to ensure adequate immune suppression while also 
minimizing the risk for adverse events.
Population PK approaches were considered to guide selection of the proposed dose and dose 
regimen.  The weight and height distributions for the simulations were taken from growth 
charts specific to DMD boys72, as well as the Cooperative International Neuromuscular 

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Research Group (CINRG) dataset.  Sirolimus concentrations in DMD boys were simulated 
using a Population PK model which included both pediatric and adult populations.73  The 
model predicted that a loading dose of 2.25 mg/m2 BSA twice daily followed by maintenance 
dose of 0.75 mg/m2 BSA twice daily for subjects ≤40 kg, and a fixed loading dose of 3 mg 
twice daily followed by maintenance doses of 1 mg twice daily for subjects >40 kg will 
achieve target trough concentration between 4.0 and 7.0 ng/mL in majority of the subjects.
Objectives and Endpoints:
Objective:
Endpoints:
To assess the effect of sirolimus on 
complement activation when administered 
according to the protocol.

Percent change from baseline of 
nadir in C4 levels through Day 30.

Percent change from baseline of 
nadir in platelet levels through 
Day 30.

Change from baseline of NAb 
antibody titers through Day 30.
To evaluate the safety of sirolimus when 
administered according to the protocol.

Incidence, severity, and causal 
relationship of treatment-emergent 
AEs through 30 days post-treatment.

Incidence and magnitude of 
abnormal laboratory findings 
through 30 days post-treatment. 
Cohort Design: 
For this cohort, in addition to all study procedures and timing in the Study C3391001 
protocol, subjects will receive sirolimus 10 days prior to and for 14 days following infusion 
with PF-06939926.
Information for sirolimus may be found in the Single Reference Safety Document, which for 
this study will be the United States Prescribing Information.71  Additional safety information 
on potential risk related to the use of sirolimus in the pediatric population is provided below. 

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Cohort Schedule of Activities:
All procedures detailed in the protocol will be conducted as detailed in the Schedule of 
Activities.  Additionally, for this cohort, the following will apply: 
Period
Treatment
Visit Number
Visit 
2.2a, d
Visit 
2.3
Remote 
Visit 2.4
Phone 
Contact 
Visit 3
Remote 
Visit 3.1
Phone 
Contact
Visit 4
Week 
2
Remoted
Visit 4.2
Remoted
Visit 5.2
Visit Window
Day -10 Day -7
Day -5b
(+3 days)
Day 4
(±1 day)
Day 6 b, c 
(+3 
days)
Day 14
(±1 
day)
Day 17
(±1 day)
Day 25
(±1 day)
Administration 
of sirolimus
X
→
→
→
→
X
Platelets and 
C4 Levels
X
X
Sirolimus 
trough level 
(locally)
X
X
X
Sirolimus dose 
level 
adjustment
X
X
a. Phone communication in the AM between site staff and subject and/or caregiver as a reminder to begin 
taking the sirolimus if dispensed previously at the baseline visit.
b. Sirolimus dose adjustments once the trough concentration level from Day -7 is available but at least 2 days 
prior to dosing.
c. Sirolimus dose adjustments once the trough concentration level from Day 4 is available.
d. Unless clinical concern and/or subject preference warrants an in-person visit, remote visits may be 
performed.
Number of Subjects:
Up to 8 non-ambulatory subjects will receive a single dose of PF-06939926 in this cohort.  
Additionally, for the subjects in this cohort, sirolimus will be administered as described in the 
table below.  In order to mitigate unanticipated risks to subject safety, the PF-06939926 
dosing interval will be at least 3 weeks between subjects for the first 3 subjects.  If no safety 
concerns are identified 3 weeks after the third subject is infused, then PF-06939926 dosing 
may proceed at ≥2 week intervals for the additional subjects in the cohort.  

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Pending review of data in non-ambulatory subjects, up to 5 ambulatory subjects may also be 
included in this cohort, as determined by the sponsor.  Continued dosing at any point in this 
cohort will be at the discretion of the sponsor, based on emerging data. 
Subject Eligibility Criteria:
The inclusion and exclusion criteria below is in addition to meeting all eligibility criteria 
listed in Section 4.  The inclusion criterion of age described here will supersede that in 
Section 4.
Inclusion Criteria 
Subjects must meet the following inclusion criterion to be eligible for enrollment into the 
sirolimus cohort:
1) >8 years of age
Exclusion Criteria
Subjects are excluded from this cohort if any of the following criteria apply:
1) Hypersensitivity to sirolimus or intolerance to soy, including a history of angioedema;
2) Concomitant use with strong CYP3A4/P-gp inducers (including but not limited to 
rifampin, rifabutin, or St. John’s wort) or strong CYP3A4/P-gp inhibitors (including but not 
limited to ketoconazole, voriconazole, itraconazole, erythromycin, telithromycin, or 
clarithromycin) that decrease or increase sirolimus concentrations.  The full list may be found 
at the US Food & Drug Administration website. (Drug Development and Drug Interactions: 
Table of Substrates, Inhibitors and Inducers.)
Potential risks associated with experimental use of sirolimus in pediatric subjects:
Additionally to potential risks listed in the sirolimus label71 for the 2 indicated populations, a 
targeted review of post-marketing off label use reports from pediatric subjects within 30 days 
of starting sirolimus was performed and identified the following additional potential risks:
Based on a cumulative safety review (through 31 March 2021) of 255 cases related to the off 
label pediatric use within 30 days of starting sirolimus administration, the observed safety 
profile did not significantly differ from the one described in the label for the approved 
indications.71  The majority of  reported SAEs were reported in the system organ classes 
(SOCs) of Blood and lymphatic system disorders, Infections & Infestations, and Respiratory, 
thoracic and mediastinal disorders.  The anticipated potential risks associated with short term 
use of sirolimus in the pediatric DMD population may include:

mouth ulcer (stomatis, mouth ulceration, mucosal disorder, oral mucosal blistering);

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
gastrointestinal disorders (nausea, diarrhaea, vomiting, haematemesis, abdominal 
pain/discomfort);

metabolic disorders (hyperlipidaemia, hypertriglyceridaemia, dyslipidaemia);

skin conditions (skin rash, skin erosion, skin irritation);

increased susceptibility to infection (label warning: herpes zoster, bacterial 
pneumonia, sepsis, septic shock, cellulitis);

liver abnormalities (hepatic function abnormal, increased ALT and/or AST);

impaired healing (also in Warnings and Precautions);

pyrexia;

swelling/edema.
As per the warnings in the sirolimus label, there is a potential risk of angioedema with 
sirolimus alone, and with concomitant use of ACE inhibitors.  If angioedema were to occur 
in this study during treatment with sirolimus, sirolimus dosing should be discontinued 
immediately.  Subjects with angioedema prior to infusion with PF-06939926 will be 
withdrawn from this cohort.  The following AEs may be challenging to evaluate for 
relatedness if they occur during the co-administration period, since they have been reported 
for both sirolimus and PF-06939926 during the first 2 weeks of administration: hypertension, 
anemia, nausea, diarrhea, headache, fever, thrombocytopenia, hemolytic uremic syndrome, 
thrombotic microangiopathy.
Cohort Intervention: Subjects in this cohort will receive oral sirolimus solution as follows: 
Subject Age/ 
Weight Range
≤40.0 kg
>40.0 kg
Day -10 before 
PF-06939926 
infusion
Oral sirolimus solution at loading 
dose of 2.25 mg/m2 BSA given 
twice daily. 
Oral sirolimus solution at 
loading dose 3 mg given twice 
daily. 
Day -9 to Day -1 
(or sooner if dose 
adjustment is 
required based on 
the Day -7 trough 
concentration 
level) before 
PF-06939926 
infusion and on 
the morning of 
Day 1.
Oral sirolimus solution at 
maintenance dose of 0.75 mg/m2
BSA given twice daily.
Day -7 before PF-06939926 
infusion: Draw blood to measure 
sirolimus trough concentration 
(local lab).
Oral sirolimus solution at 
maintenance dose of 1 mg 
given twice daily.
Day -7 before PF-06939926 
infusion: Draw blood to 
measure sirolimus trough 
concentration (local lab).

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Subject Age/ 
Weight Range
ŏ40.0 kg
>40.0 kg
Based on the 
Day -7 sirolimus 
trough 
concentration, 
adjust the dose on 
the day that the 
trough 
concentration level 
is received, if 
needed, to achieve 
target level of 
4-7 ng/mL 
If trough concentration is 
<3.9 ng/mL, increase dose by the 
following formula: current dose × 
(5.5 ng/mL ÷ current 
concentration).
If trough concentration is 
<3.9 ng/mL, increase dose by 
the following formula: current
dose × (5.5 ng/mL ÷ current 
concentration).
If trough concentration is within 
target range (4.0-7.0 ng/mL), 
keep at 0.75 mg/m2 BSA twice a 
day. 
If trough concentration is 
within target range (4.0-7.0 
ng/mL), keep at 1 mg twice a 
day. 
If trough concentration is 7.1-
14.0 ng/mL, reduce dose using 
the following formula: current 
dose × (5.5 ng/mL ÷ current 
concentration).
If trough concentration is 7.1-
14.0 ng/mL, reduce dose by the 
following formula: current dose 
× (5.5 ng/mL ÷ current 
concentration).
If trough concentration is >14.0,
skip 1 dose and reduce dose by 
the following formula: current 
dose × (5.5 ng/mL ÷ current 
concentration).
If trough concentration is 
>14.0, skip 1 dose and reduce 
dose by the following formula: 
current dose × (5.5 ng/mL ÷ 
current concentration).
Days 1-14 post-
PF-06939926 
infusion
Oral sirolimus solution at 
maintenance dose as determined 
above using trough 
concentrations. 
Oral sirolimus solution at 
maintenance dose as 
determined above using trough 
concentrations. 
Day 4 (±1 day) 
post-PF-06939926 
infusion
Draw blood for trough concentration for possible readjustment (same 
as described above).
Day 14 post-PF-
06939926 infusion
Draw blood for trough concentration to assess levels.
For subjects who weigh ≤40 kg, the required dose of sirolimus is dependent of the subject’s 
body surface area (BSA). BSA can be calculated per below guidance74. 
The maximum sirolimus dose administered on any day should not exceed 40 mg.  The 
duration of sirolimus administration can be extended, if needed, based on laboratory data 
consistent with an ongoing immune reaction, only after consultation and if agreed by the 
sponsor. 
ܤܵܣሺ݉2ሻൌඨܪݐሺܿ݉ሻݔܹݐሺ݇݃ሻ
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Additional guidance while providing sirolimus is listed below:
-
Investigators should review the product label information71 and the information 
provided above (see potential risks associated with experimental use of sirolimus in 
pediatric subject). 
-
Investigators should discuss any modifications to dosing regimen with the sponsor if 
a subject begins taking medications known/listed to interact with CYP3A4 or P-gp 
metabolism. 
-
Investigators should advise subjects to refrain from consuming grapefruit juice while 
taking sirolimus.
-
Investigators should advise subjects that, to minimize variability in sirolimus 
concentrations, sirolimus should be taken either consistently with food or consistently 
without food.
Study Treatments:
Subjects will temporarily replace their daily glucocorticoid regimen as described in 
Section 5.  Pending review of the data, at the discretion of the sponsor, this regimen may be 
changed to:
1. Between 1 and 4 hours prior to infusion of PF-06939926: receipt of single dose of 
IV methylprednisolone Ŏ1 mg/kg;
18. For Weeks 1, 2, 3, and 4 post-infusion of PF-06939926: switch of daily 
glucocorticoid dose to Ŏ1 mg/kg/day of oral prednisone or prednisolone; 
19. For Weeks 5, 6, 7, and 8 post-infusion: reduction of oral prednisone or prednisolone 
dose to a minimum of  0.75 mg/kg/day; 
20. For Weeks 9, 10, 11, and 12 post-infusion: reduction of oral prednisone or 
prednisolone dose to a minimum of 0.5 mg/kg/day;
21. After Week 12 post-infusion: return to pre-study daily doses of prednisone or 
prednisolone.
 
  
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Appendix 2. Alternative Measures During Public Emergencies
The alternative study measures described in this section are to be followed during public 
emergencies, including the COVID-19 pandemic.  This appendix applies for the duration of 
the COVID-19 pandemic globally or specific locations(s) and will become effective for other 
public emergencies only upon written notification from Pfizer. 
Use of these alternative study measures are expected to cease upon the return of business as 
usual circumstances (including the lifting of any quarantines and travel bans/advisories). 
Telehealth Visits
In the event that in-clinic study visits cannot be conducted, every effort should be made to 
follow-up on the safety of study subjects at scheduled visits per the Schedule of Activities or 
unscheduled visits.  Telehealth visits may be used, if/when it is not possible to have home 
visits conducted by a home healthcare service (see Home Health Visits), to continue to 
assess subject safety and collect data points.  Telehealth includes the exchange of healthcare 
information and services via telecommunication technologies (eg, audio, video, video-
conferencing software) remotely, allowing the subject and the investigator to communicate 
on aspects of clinical care, including medical advice, reminders, education, and safety 
monitoring.  The following assessments must be performed during a telehealth visit:

Review and record any AEs and SAEs since the last contact. Refer to Section 8.

Review and record any new concomitant medications or changes in concomitant 
medications since the last contact.

Confirm that the subject is adhering to the contraception method(s) required in the 
protocol. Refer to Section 4.5.2.
Study subjects must be reminded to promptly notify site staff about any change in their 
health status.
Alternative Facilities for Safety Assessments
Laboratory Testing
If a study subject is unable to visit the site for protocol-specified safety laboratory
evaluations, testing may be conducted at a local laboratory if permitted by local 
regulations. The local laboratory may be a standalone institution or within a hospital.  The 
following safety laboratory evaluations may be performed at a local laboratory (see Table 1):

Hematology panel

Chemistry panel

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•
Other (as defined in Table 1).
If a local laboratory is used, qualified study site personnel must order, receive, and review 
results.  Site staff must collect the local laboratory reference ranges and 
certifications/accreditations for filing at the site. Laboratory test results are to be provided to 
the site staff as soon as possible.   The local laboratory reports should be filed in the subject’s 
source documents/medical records.  Relevant data from the local laboratory report should 
be recorded on the CRF. 
Home Health Visits
A home health care service will be utilized to facilitate scheduled visits per the Schedule of 
Activities. Home health visits include a healthcare provider conducting an in-person study 
visit at the subject’s location, rather than an in-person study visit at the site.  The following 
may be performed during a home health visit:
•
Physical exam
•
Blood draws
•
Urine sample collection
•
Vital signs
•
C-SSRS
•
Clinical outcome assessments. 
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Appendix 3. Protocol Amendment History
The Protocol Amendment Summary of Changes Table for the current amendment is located 
directly before the table of contents (TOC).  The protocol amendment summary of changes 
tables for past amendment(s) can be found below:
Original Protocol
20 July 2017
Not applicable (N/A)
Amendment 1
03 December 2018 
 
 
 
 
 
1. Addition of the option of an intermediate dose 
level to which the second cohort may be 
de-escalated in the event of dose -limiting 
toxicity observed at the highest dose level;
 
 
 
3. Allowance for the option of broadening the 
window between the Baseline and Dosing 
visits to accommodate scheduling challenges 
and ensure timely delivery of PF-06939926 to 
site for dosing;
4. Allowance for more flexibility as far as the 
method for collecting muscle biopsies 
(ie, open and/or needle); 
5. Allowance for the option of performing a 
locally-read echocardiogram if attempted 
cardiac MRI cannot be evaluated and a repeat 
is unlikely to resolve the issue;
6. Addition of oral prednisolone as an option for 
the 3 months following study drug 
administration;
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7. Allowance to modify the regimen of the 
required background glucocorticoid regimen 
after the first year post-treatment;
8. Removal of language that inadvertently 
indicated that 12 planned subjects would be 
split evenly between the 2 planned cohorts; 
9. Broadening of the option of adding several 
additional subjects to either cohort for reasons 
other than safety (eg, to also better understand 
any preliminary efficacy data);
10. Clarification that a pause to enrollment for 
assessment of the biopsies obtained from first 
3 subjects’ of the second cohort would only be 
necessary if no measurable transgene 
expression was observed in the first cohort 
(ie, lower dose level);
11. Clarification that receipt of the influenza 
vaccine within 30 days prior to receipt of 
study drug or 3 months after is prohibited;
12. Allowance for flexibility of the weight-based 
calculations for the required glucocorticoids 
for practical purposes and to align with 
standard of care;
13. Emphasis that 2 site personnel should confirm 
subject information entered into the electronic 
system for enrollment, as these data are 
critical for ensuring that the appropriate 
amount of PF-06939926 is shipped to the site 
for the given subject;
14. Clarification that infusion site monitoring is 
only required from start of infusion through 
second month post-infusion, unless clinically 
indicated;
15. Clarified that any cardiac MRI taken within 
3 months prior to Screening and deemed 
adequate for confirming eligibility for this 
study may replace the need for a Screening 
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16. Replaced “study entry” with “the Baseline 
visit” for clarity;
17. Administrative clarifications (eg, to ensure 
consistency between Schedule of Activities 
and other sections of the protocol).
Amendment 2
14-Feb-2019
1. In response to observed nausea, vomiting and 
symptoms resembling acute viral 
gastroenteritis following the administration of 
PF-06939926 in this current trial, additional 
safety monitoring has been incorporated into 
the Treatment period (ie, if adverse events 
[AEs] possibly related to PF-06939926 are 
observed, subjects should not be discharged 
until the events have resolved or can be 
managed by the subject and/or caregiver; 
upon discharge, subjects should stay near the 
investigational site to enable easy follow-up in 
the event of any emergent AEs through the 
Week 1 visit, or longer if clinically indicated; 
subjects may also return to the investigational 
site on Day 4 [±1 day] for safety and viral 
vector shedding biospecimen collection, as 
well as assessment of any new or worsening 
adverse events or changes to concomitant 
medications);
1) Guidance added for practicing good general 
hygiene for 1-2 months following 
administration of PF-06939926 in the Activity 
section of the protocol (Section 4.5.1), given 
that PF-06939926 is of a viral vector;
2) To obtain better characterization of the viral 
vector shedding kinetics during the first year 
following administration of PF-06939926, 
4 more biospecimen collection timepoints 
have been added.  Safety will also be 
monitored at these additional visits via 
collection of safety labs and discussion with 
the subject regarding any new or worsening 
adverse events or changes in concomitant 
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3) Extension of the Screening visit window from 
84 to 126 days prior to Day 1 (or 112 days 
relative to Baseline) to allow for more 
flexibility in the event of enrollment pauses.  
However, should the period between 
Screening and Baseline visits exceed 84 days 
(12 weeks) for a given subject, then the 
Screening labs, thigh and upper arm imaging, 
and functional assessments should be repeated 
to (re)confirm eligibility prior to enrollment;
4) Mention that medications may be given to 
treat or prevent adverse events possibly 
related to PF-06939926 (eg, antiemetics or 
antihistamines for nausea and vomiting 
events) (Section 5.7.1);
5) Administrative changes to improve 
consistency and clarity throughout document 
(eg, correction to the study design schematic 
in which the long-term follow-up for Cohort 2 
was accidentally omitted; correction in 
duration of study from 4 to 5 years of 
follow-up; clarification in Section 4.2 that 
cardiac magnetic resonance imaging from 
within 3 months prior to Screening can be 
used to assess eligibility as already described 
in Section 6.1).
Amendment 3
10 May 2019
1. In response to observed acute renal injury 
associated with complement activation 
following the administration of PF-06939926, 
additional safety monitoring and appropriate 
medical management has been incorporated 
into the Treatment and 1st Year Follow-up 
periods:

If adverse events (AEs) indicative of renal 
injury and/or complement activation 
occur, subjects will be evaluated promptly 
by the investigator and/or medically 
qualified individual(s) for proper care and 
management; 

Upon discharge from the planned 24-hour 
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investigational site to enable easy 
follow-up in the event of any emergent 
AEs through the Day 14 (Week 2) visit, 
which will now be in-clinic, or longer if 
clinically indicated; 
•
Subjects will return to the investigational 
site on Day 10 (in addition to Days 4, 
7 and 14) for biospecimen collection, as 
well as for assessment of any new or 
worsening adverse events, changes to 
concomitant medications, and 
confirmation of adequate fluid intake and 
output; 
•
Addition of a remote Day 21 (Week 3) 
biospecimen collection and wellness 
check-in visit;
•
Addition of triplicate electrocardiograms 
at Weeks 2 and 4; 
•
Addition of body temperature collected at 
all timepoints for vitals from prior to 
PF-06939926 infusion through Week 2, 
and again at Week 4;
 
 
 
 
 
 
 
 
 
•
Requirement for eculizumab to be 
accessible by the investigational sites for 
use if complement activation observed;
•
Guidance that eculizumab use would 
require either prior meningococcal 
vaccination (at least 2 weeks prior to 
dosing) and/or prophylactic antibiotics for 
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meningococcus for the duration 
eculizumab is needed; 

Guidance added for monitoring fluid 
intake and urine output through 
Week 4 following administration of 
PF-06939926 in the Activity section of the 
protocol (Section 4.5.1).
1) Shift of several safety assessments 
(ie, Physical and Neurological Exam, 
Columbia Suicide Severity Rating Scale) from 
Day 7 to Day 14, now that Day 14 is an in-
clinic (previously a remote visit).
2) Additional extension of the Screening visit 
window from 126 to 196 days prior to Day 1 
(or 182 days relative to Baseline) to allow for 
more flexibility in the event of enrollment 
delays or pauses so as to minimize burden on 
subjects who would otherwise be required to 
unnecessarily repeat all Screening 
assessments.  However, as is reflected in 
Amendment 2, should the period between 
Screening and Baseline visits exceed 84 days 
(12 weeks) for a given subject, then the 
Screening labs, thigh and upper arm imaging, 
and functional assessments should be repeated 
to (re)confirm eligibility prior to enrollment.
3) Allowance for flexibility in timing of 
post-treatment muscle biopsies (ie at either 
2 or 3 months and either 6 or 12 months vs. 
only at 2 and 12 months) for better 
characterization of peak transgene expression 
and distribution.  The specific timepoint for 
each biopsy for a given subject will be 
determined by the sponsor but with 
investigator input.  Despite this newly added 
flexibility, no subject will undergo muscle 
biopsies at more than 3 total visits.
4) Modification to lower limit of age range for 
eligibility from 5 years old to 4 years old, so 
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full age range planned for the next phase of 
clinical drug development. 
5) Allowance for reduced pause between 
subjects, with external data monitoring 
committee (E-DMC) approval, provided that 
6 consecutive subjects who are dosed at the 
current 3-6 week intervals at the given dose 
level meet no enrollment pause criteria.
6) Allowance for use of prophylactic antiemetics 
to assess whether these are effective in 
preventing nausea and/or vomiting during the 
first 7-10 days following administration of 
PF-06939926.
7) Update of blood sampling limits in this 
pediatric study, given the recent safety events 
that require additional safety monitoring and 
blood tests, and particularly for this type of 
gene therapy study with a single infusion, the 
first several months after which are most 
critical. 
8) Removal of erythrocyte sedimentation rate 
(ESR), given that this local laboratory test 
does not appear to be a useful marker for 
identifying inflammatory events that may be 
related to PF-06939926, and even less so 
given the additional lab tests and safety 
monitoring included under this amendment (as 
described above).
9) Administrative changes to improve 
consistency and clarity throughout document 
(eg, fixed typographical error in study drug 
name within study schematic; clarification that 
enrollment pause criteria due to safety applies 
to any dose level; clarified that safety risk 
identified during this study will be described 
in the Investigator’s Brochure).
Amendment 4
20 February 2020
1. Number of subjects to be enrolled increased 
from 12 to 24 in an effort to better evaluate 

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safety of PF-06939926, per availability of 
drug product.
 
 
 
 
 
2) Increased the duration of length of entire 
study given increase in number of subjects to 
be enrolled, which is helpful for investigators 
to set expectations as to when they can expect 
final study results, and increased duration of 
subject participation from approximately 
5 years to 5.5 years, given the extended 
Screening window as per Amendment 2.
3) Addition of possible local laboratory samples 
to be collected and tested on Study Days 7-10 
and extension of complement biomarker 
collection through Week 8, or perhaps longer 
if outside normal range, so as to ensure better 
understanding of possible changes in 
laboratory results during this period, as well 
as to allow for closer safety monitoring per 
communications between the investigators 
and sponsor.
4) Removed reference to “blood smear” in 
Schedule of Activities, Section 6.3-6.6 and 
Table 1, given that this not a separate test and 
is already part of the hematology panel since 
the start of the study.
5) Assessment of drug concentrations of 
PF-06939926 changed to a titer method, 
which will be used to adjust referenced doses.  
Use of the more precise titer assay was 
implemented per regulatory request.
6) Broadened flexibility to increase the dosages 
of the protocol required glucocorticoids just 
prior to (ie, methylprednisolone) and for at 
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least 3-months following administration of 
PF-06939926 to explore whether increased 
doses may mitigate risk of adverse immune 
reactions.
7) Expanded the list of examples of medications 
that can be administered to treat or prevent 
adverse events to include 
immunosuppressants and complement 
inhibitors as these may be used to mitigate 
risk of complement activation.
8) Removed reference to a 6 milliliter (mL) vial 
of investigational product, PF-06939926, as 
the vial size will be increased; the fill volume 
will remain 5 mL, as reflected.
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Amendment 5
20 July 2020
1. Expanded study population to include 
non-ambulatory subjects with Duchenne 
muscular dystrophy (DMD), in an effort to 
broaden the safety evaluation of PF-06939926 
in this patient population (Title page, Section 
3.1, and as noted below),
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1) Updated current therapies for DMD given 
recent regulatory approval of another 
exon-skipping medication, ie, VYONDYS 
53™(Section 1.2.1).
2) Broadened Rationale for Selected Patient 
Population Section (1.4.3) to include 
non-ambulatory subjects.
3) Removed flexibility around biospecimen 
collections for local laboratory 
testingfollowing administration of 
PF-06939926, such that local laboratory 
testing is now required on Days 5-9 to ensure 
consistent safety monitoring during this 
period (Schedule of Activities, Sections 3.3, 
6.3).
 
 
 
 
 
5) Increased number of subjects to be enrolled 
from 24 to up to approximately 30 to 
accommodate up to approximately 
20 ambulatory DMD subjects, and now up to 
approximately 10 non-ambulatory DMD 
subjects, per availability of drug product 
(Sections 1.4, 3.1, 3.2, 9.1 Figure 2, and 
throughout protocol).
6) Added flexibility to broaden duration of 
infusion and total volume of PF-06939926, as 
these may be needed for subjects >50 kg 
(Sections 3.1, 5.4).
7) Removed the anti-smooth muscle antibody 
assay and anti-liver kidney microsomal 
antibody type 1 laboratory tests for 
autoimmune-mediated hepatitis as Exclusion 
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Criteria, given the lack of observed hepatic 
injury associated with PF-06939926 
(Schedule of Activities, Sections 4.2, 7.2.1, 
Abbreviations).
8) Increased the dose of intravenous 
methylprednisolone prior to dosing from ≥
1 to ≥2 mg/kg, and similarly for oral 
prednisone or prednisolone from ≥
1 mg/kg/day to ≥2 mg/kg/day for the first 
2 weeks following PF-06939926 in order to 
further mitigate risk of an adverse immune 
response,  before adjusting back down to ≥
1 mg/kg/day for the remainder of the first 
month (Schedule of Activities, Section 5, 5.4, 
6.3, 6.4).
9) Included mention of other inactivated 
vaccinations beyond influenza by which 
administration would need to be restricted 
relative to administration of PF-06939926, in 
order to accommodate possible forthcoming 
vaccinations, such as that for severe acute 
respiratory syndrome coronavirus 2 
(SARS-CoV-2) (Sections 4.2 and 5.7.2). 
10) Added new and clarifying language to 
accommodate addition of non-ambulatory 
subjects in the study including the following:
a.
Clarified that consent will be obtained 
directly from subjects of age of 
majority, and differentiated role of 
caregivers for subjects who are minors 
(Sections 4, 6.1);
b. Modified certain eligibility criteria to 
accommodate non-ambulatory subjects 
(ie, age, weight, functional 
performance, cardiac function) 
(Section 4);
c.
Added distinction between functional 
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vs. non-ambulatory subjects (Schedule 
of Activities, Sections 6, 7.5);
d. Added flexibility in the neurological 
examination for non-ambulatory 
subjects, since certain domains 
(eg, station and gait) will not apply to 
this sub-population (Section 7.2.3);
e.
Included instructions for measuring 
height and weight of non-ambulatory 
subjects (Section 7.2.4, referenced in 
Section 5.3.1);
f.
Removed requirement that subjects are 
to be supine for vital signs collection 
in order to eliminate an unnecessary 
burden on non -ambulatory subjects 
(Section 7.2.5 and throughout); 
g. Added language around managing 
changes in cardiac imaging for 
non-ambulatory subjects (Section 
7.2.7.2);
h. Added adult versions of the Columbia 
Suicide Severity Rating Scale 
(C-SSRS) to be completed directly 
with subjects who are >12 years of age 
at Screening, and added language that 
site staff can physically complete the 
form on behalf of the subject, if 
needed (Section 7.2.8, as well as 
Schedule of Activities, Section 6);
 
 
 
j.
Added flexible language around the 
collection of biopsies for both 
ambulatory (as per the Protocol 
Administrative Change Letter, dated 
03Oct2019) and now specifies the 
muscle groups for collection of needle 
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biopsies, as well as details regarding 
collections from non-ambulatory 
subjects (Section 7.6, and 1.4.2, which 
indicates that up to a maximum of 
3 biopsy procedures will occur per 
subject);
k. Added new Clinical Outcomes 
Assessments for the DMD non-
ambulatory sub-population to be 
included with this amendment and 
added clarification around which 
assessments are to be completed by 
which subjects based on ambulatory 
status and age (Section 7.7, as well as 
Sections 2 and 6); 
l.
Added clarification that data analyses 
may also be split by ambulatory status 
(Section 9.4).
11) Removed specification that echocardiograms 
should be performed using a 2-dimensional 
(2-D) imaging collection method, as many 
sites may now have 3-dimensional (3D) 
ejection fraction capabilities (Section 7.2.7.2).
12) Added clarification around documentation of 
medication compliance if the subject dosing 
diary for daily oral prednisone or prednisolone 
is not utilized (Schedule of Activities, 
Section 7.2.9.1).
13) Clarified that version 2.0 of the Performance 
of Upper Limb scale is used in this study 
(Schedule of Activities, Sections 4.1, 6.1, 
7.5.6). 
14) Added clarification that ideally the same 
caregiver will complete the clinical outcomes 
assessments throughout the study for 
consistent reporting, when feasible 
(Section 7.7). 
15) Removed detail around expected division of 
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from Sample Size Determination 
(Section 9.1), because already described 
elsewhere (Sections 3.1, 3.2 and Section 3.5, 
respectively). 
16) Included other areas of expertise that may be 
incorporated into the E-DMC (Section 9.6).
17) Administrative changes to improve 
consistency and clarity throughout document 
(eg, updated appendix of abbreviations to 
include new terms; replaced previously 
defined terms with abbreviations or acronyms 
where appropriate; corrected error for hybrid, 
not human, creatine kinase [hCK] [Section 
1.1]: corrected error to reflect Zarit Burden 
Interview vs. Zarit Burdent Inventory 
[Section 7.1.1.1 and Abbreviations]; added 
clarity for consistency that daily 
glucocorticoid regimen is required and 
compliance should be captured through at 
least 1 year after receipt of PF-06939926 
[Schedule of Activities, Sections 1.5.1, 5]; 
added clarity around permitted medications to 
treat or prevent adverse events [Section 5.7.1]; 
adjusted placement of clarification for repeat 
Screening labs [Section 6.1]); added 
clarification that concomitant medications or 
therapies may also be considered when 
assessing the causality of a serious adverse 
event.
Amendment 6
03 March 2021
1) Added the following Exclusion Criteria:

For clarification: Prior treatment with 
gene therapy, defined as any therapy 
introducing exogenous DNA or 
intended to permanently alter the 
endogenous DNA. Gene therapy 
(other than study drug) will be 
prohibited for the duration of the 
study.

For clarification: Exposure within 6 
months prior to Screening (Visit 1) to 
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dystrophin expression (including, but 
not limited to exon-skipping agents 
and nonsense read-through). These 
treatments will also be prohibited 
during the period between Screening 
(Visit 1) and Day 1 (Visit 3) and for 
the first year of the study. 

To prevent hypersensitivity reactions: 
Known hypersensitivity to any of the 
components of the study drug or 
solution for infusion, such as 
hypersensitivity to albumin or a 
diagnosis of (or symptoms suggestive 
of) hereditary fructose intolerance 
(HFI).  Symptoms suggestive of HFI 
include nausea, vomiting, bloating, 
stomach cramps, or diarrhea following 
the ingestion of sweet foods or drinks, 
or a pattern of avoiding sweet foods or 
drinks.

To account for elevated values as a 
result of treatment with steroids that 
do not reflect renal impairment: 
Changed Cystatin C criterion from > 
1.0 mg/L to >1.2 × ULN

Platelets <150 × 10
3/µL;
2) For clarification, added the length of time 
that the study drug is stable. (Section 5.4)
3) Schedule of Activites - Added that the 
baseline NAb to AAV: will be collected and 
sent to the central laboratory, but will only be 
analyzed and reviewed prior to Day 1 (Visit 
3), if the study team determines that Day 1 
(Visit 3) will be more than 55 days after the 
Screening visit (Visit 1).
4) Clarified the use of cardiovascular 
medications and changed may to must for the 
receipt of the Meningococcal Vaccine. 

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(Section 5.7.1) so that there is consistency 
with among all protocols for this program. 
5) Added Cardiac Troponin to Triggers for 
Additional Safety Monitoring 
(Section 7.2.12).
6) Clarified when the primary safety analysis 
will be conducted (Section 9.5).
7) To allow for the sites to have flexibility, 
added that trained respiratory therapists can 
perform PFTs (Section 7.5). 
8) Added an appendix to include alternative 
measures during public emergencies 
(Appendix 1).
9) Added additional abbreviations to 
Appendix 2.
 
Amendment 7
03 June 2021
1) Section 1.5.3 Other Risks: Added the 
possible risks of the use of a PICC line for 
blood draws since a PICC line may be used. 
2) Section 1.4 Study Design Rationale, 
Section 3.1 Study Overview, Section 3.2 
Planned Number of Subjects, and Section 9.1 
Sample Size Determination: changed the 
sample size to 35.
3) Section 3.5 Dose Progression and Stopping 
Rules: Changed GLDH >2.5 × ULN to “Any 
set of laboratory results meeting Hy’s Law” 
for the criteria to halt further enrollment, and 
clarified that the E-DMC will review data for 
the subjects with the clinical events that 
prompted the review instead of all available 
data.  The E-DMC has reviewed 3 cases of 
elevated GLDH levels and agreed that the 
review of subsequent cases was not necessary 
unless Hy’s Law was met. 
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4) Section 5 Study Treatments: Adjusted the 
glucocorticoid regimen post-infusion with 
PF-06939926 to allow for a slower tapering 
and to minimize the risk of adrenal 
insufficiency.
5) Section 5.7.2 Prohibited Therapies: Added 
that subjects will be able to receive an mRNA, 
or DNA-based, or non-replicating viral vector 
vaccine (eg, against SARS-CoV2) within 
specified time windows.
6) Added a requirement that subjects who  
experience an event compatible with aHUS 
will be screened for a genetic predisposition 
to aHUS to obtain information that may 
contribute to an understanding of the risk for 
developing aHUS.
7) Section 7.2.1 Clinical Laboratory: Clarified 
that the PICC line can only be used for blood 
draws and not study drug administration. 
8) Table 1 Central Laboratory Tests: Added 
magnesium to the chemistry panel.
9) A cohort was added as an appendix to 
evaluate the use of sirolimus to mitigate the 
risk of complement-mediated events related to 
PF-06939926.
10) Changed “first” cohort to “low-dose” 
cohort and “second” cohort to “high-dose” 
cohort throughout the document. 
Amendment 8
02 September 2021
1) Schedule of Activities Footnote I and 
Section 6.1: Changed “may’ to “will” be 
collected and tested for the ADA to mini-
dystrophin at screening and added ADA to 
mini-dystrophin at Week 2/Day 14 to the SoA 
and Section 6.4. This change is to identify 
subjects with a potentially higher risk of 
immune reactions. 
2) Schedule of Activities Footnote L: added 
that DMD genetic testing will only be 

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obtained and sent to the central lab if required 
to confirm the diagnosis of DMD. 
3) Section 4.2 Exclusion criteria: Addition of 
exclusion criterion to exclude subjects with 
specific mutations in the dystrophin gene 
considered to increase the risk of immune-
mediated adverse reactions. This was a 
recommendation by the E-DMC based on the 
review of the immune and genetic data from 
studies C3391001 and C3391003.
4) Appendix 1: Sirolimus Cohort Schedule of 
Activities: Remote Visit 2.4 Phone Contact, 
the range of the visit window was changed 
from “+2 days” to “+3 days” to accommodate 
for the length of time it could take to receive 
the sirolimus trough concentration level back 
from the lab. Also removed the footnote that 
referenced the Platelet and C4 levels and 
changed “additional clinical safety labs” to 
“Platelets and C4 Levels” within the table. 5) 
Appendix 1: Sirolimus Cohort Schedule of 
Activities: Remote Visit 3.1 Phone Contact, a 
phone contact was added for possible 
sirolimus dose level adjustment on Day 6 (+3 
days) along with Footnote b “Sirolimus dose 
adjustments as soon as the trough 
concentration level from Day 4 is available.” 
This information was included on the 
sirolimus dosing table within Appendix 1 but 
was inadvertently originally omitted from the 
sirolimus cohort Schedule of Activities. 
6) Appendix 1: Sirolimus Cohort Schedule of 
Activities: “Sirolimus trough level” replaced 
with “Sirolimus trough level (locally)” This 
information was included on the sirolimus 
dosing table within Appendix 1 but was 
inadvertently originally omitted from the 
sirolimus cohort Schedule of Activities. 
7) Appendix 1: Sirolimus Cohort Schedule of 
Activities: For remote visits 4.2 and 5.2, the 
following sentence was added as footnote C: 
“Unless clinical concern and/or subject 

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preference warrants an in-person visit, remote 
visits may be performed.” This sentence was 
added to allow for flexibility so an in person 
visit is allowable.
8) Appendix 1: Sirolimus Cohort: Cohort 
Intervention: Added  guidance on how to 
calculate the BSA for the sirolimus dose when 
required based on the subject’s weight. 
9) Added Appendix 3: Protocol Amendment 
History
10) Appendix 4 Abbreviations: Added 
additional abbreviations.

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Appendix 4. Abbreviations
This following is a list of abbreviations that may be used in the protocol.
Abbreviation
Term
%pFVC
percent predicted forced vital capacity
4SC
Four Stair Climb
6MWD
six minute walk distance
6MWT
Six Minute Walk Test
AAV
adeno-associated virus
AAV9
adeno-associated virus, serotype 9
ACE
angiotensin converting enzyme
ADA
anti-drug antibodies
ADLs
activities of daily living
AE
adverse event
aHUS
atypical hemolytic uremic syndrome
ALT
alanine aminotransferase
ALP
alkaline phosphatase 
ANA
Antinuclear antibody
ANC
absolute neutrophil count
aPTT
activated partial thromboplastin time
AST
aspartate aminotransferase 
ATS
American Thoracic Society
BBS
Biospecimen Banking System
BMD
Becker muscular dystrophy
BP
blood pressure
BSA
Body surface area
C4
Complement 4
C5b-9
Complement 5b-9
CDC
Center for Disease Control
cDNA
complementary DNA
CE
clinical evaluator
CINRG
Cooperative International Neuromuscular Research Group
CIOMS
Council for International Organizations of Medical Sciences
CK
creatine kinase
CK-MB
creatine kinase myocardial b fraction
CMV
Cytomegalovirus
CNS
central nervous system
COVID-19
Coronavirus disease 19
CR
cysteine-rich
CRF
case report form
CRP
C-reactive protein
CSA
clinical study agreement
C-SSRS
Columbia Suicide Severity Rating Scale
CT
c-terminal
cTnI
cardiac troponin I

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Abbreviation
Term
CYP3A4
Cytochrome P450 3A4
DAP
Dystrophin-associated protein
DILI
drug-induced liver injury
DGC
Dystrophin-associated glycoprotein complex
DMD
Duchenne muscular dystrophy
DNA
deoxyribonucleic acid
EC
ethics committee
ECG
Electrocardiogram
E-DMC
external data monitoring committee 
EDP
exposure during pregnancy
EDTA
edetic acid (ethylenediaminetetraacetic acid)
ELISpot
enzyme-linked immunospot 
ELISA
enzyme-linked immunosorbent assay
EQ VAS
EuorQol visual analogue scale
ERS
European Respiratory Study
ESR
erythrocyte sedimentation rate
ET
Early Termination
EU
European Union
EudraCT
European Clinical Trials Database
FDA
Food and Drug Administration
FEV
forced expiratory volume
FIH
first-in-human
FIP
first-in-patient
FVC
forced vital capacity
GCP
Good Clinical Practice
GGT
gamma-glutamyl transferase
GLDH
glutamate dehydrogenase
GMP
good manufacturing practice
HAV
hepatitis A virus
HBsAG
hepatitis B surface antigen
hCK
hybrid creatine kinase
HCVAb
hepatitis C antibody
HFI
hereditary fructose intolerance
HR
heart rate
HT
height
IA
interim analysis
IB
Investigator’s Brochure
ICD
informed consent document
ICH
International Conference on Harmonisation
ID
Identification
IFA
Immunofluorescence assay
CCI

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Abbreviation
Term
IHC
Immunohistochemistry
IM
Intramuscular
INFα
interferon alpha
INFβ
interferon beta
IgG
immunoglobulin G
IgM
immunoglobulin M
IND
investigational new drug application
INR
international normalized ratio
IP-10
Interferon gamma-induced protein 10
IRB
institutional review board
IRT
interactive response technology
ITAC
Interferon-inducible T-cell alpha chemoattractant
ITR
inverted terminal repeats
IV
Intravenous
K2 EDTA
dipotassium ethylenediaminetetraacetic acid 
Kda
kilo-dalton
Kg
Kilogram
LC-MS
liquid chromatography/mass spectrometry
LFT
liver function test
LSLV
last subject last visit 
LVEF
left ventricular ejection fraction
MenACWY
meningococcal conjugate
MenB
serogroup B meningococcal
MHP
mental health provider
MRI
magnetic resonance imaging
mRNA
messenger ribonucleic acid
MSW
Master’s level Clinical Social Workers
N
Number
N/A
not applicable
NAb
neutralizing antibodies
NOAEL
no observed adverse effect level
NSAA
North Star Ambulatory Assessment
qPCR
quantitative polymerase chain reaction
QTcF
Fridericia’s correction formula
PACL
protocol administrative change letter
PCD
primary completion date
PD
pharmacodynamics
PEFR
peak expiratory flow rate
PFT
pulmonary function test
P-gp
P-glycoprotein
PI
principal investigator
PICC
peripherally inserted central catheter
PK
pharmacokinetic(s)
PNP
psychiatric nurse practitioners

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Abbreviation
Term
P-selectin: protein-selectin
P(platelet)-selectin glycoprotein ligand-1
PT
prothrombin time
PUL
Performance of Upper Limb
rAAV
Recombinant AAV
RBC
red blood cell
RNA
ribonucleic acid
ROA
route of administration
SAE
serious adverse event
SAP
statistical analysis plan
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
SD
Standard deviation
SMA
Spinal muscular atrophy
SoA
schedule of activities
SOC
system organ class
SOP
standard operating procedure
SRSD
single reference safety document
SSID
single subject’s identification
TBili
total bilirubin
TEAEs
treatment emergent AEs
temp
temperature
TG
Transgene
ULN
upper limit of normal
UL-PROM
Upper Limb Patient Reported Outcome Measure
US
United States
USPI
United States Package Insert
Vg
vector genomes
WB
Western blot
Wt
weight
CCI
CCI

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