An Open-Label Study of the Safety, Tolerability, and Pharmacokinetics of Oral NNZ-2591 in Phelan-McDermid Syndrome (PMS-001)
Phase: PHASE2
Conditions: Phelan-McDermid Syndrome
Sponsor: Neuren Pharmaceuticals Limited

 
 
CLINICAL TRIAL PROTOCOL 
An Open-Label Study of the Safety, Tolerability, and Pharmacokinetics of Oral NNZ-2591 in Phelan 
McDermid Syndrome 
 
Protocol Number:   
NEU-2591-PMS-001  
Drug Development Phase: 
2 
Protocol Version No.: 
3.0 
Release Date: 
October 30, 2023 
NCT Number: 
NCT05025241 
Sponsor Address: 
Neuren Pharmaceuticals Ltd. 
Suite 201, 697 Burke Road 
Camberwell, VIC 3124 
Australia 
Medical Monitor: 
 
 
  
 
Program Director: 
 
 
 
 
 
 
 
 
Confidentiality Statement 
All information contained within this protocol is confidential. It may not be reproduced, copied, or disseminated in 
any manner without the prior written consent of Neuren Pharmaceuticals Ltd. 
Clinical trial No. Neu-2591-PMS will be conducted in accordance with this protocol, ICH  
GCP, as published in the Federal Register on 09 May, 1997, and all applicable regulations. 

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CONFIDENTIALITY STATEMENT 
 
All information concerning the Investigational Medicinal Product, supplied by Neuren Pharmaceuticals 
Ltd. in connection with this study and not previously published, is considered confidential and proprietary 
information. This information includes the Investigator’s Brochure, Clinical Protocol, and Case Report 
Forms. This confidential information shall remain the sole property of Neuren Pharmaceuticals Ltd. and 
shall not be disclosed to others without prior written consent from Neuren Pharmaceuticals Ltd. and shall 
not be used except in the performance of this study. 
 
The information developed during the conduct of the clinical study is also considered confidential and 
will be used by Neuren Pharmaceuticals Ltd. in connection with the development of the Investigational 
Medicinal Product. This information may be disclosed as deemed necessary by Neuren Pharmaceuticals 
Ltd.  

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TABLE OF CONTENTS
CONFIDENTIALITY STATEMENT .....................................................................................................2
LIST OF ABBREVIATIONS.............................................................................................................8
PROTOCOL APPROVAL...............................................................................................................12
PROTOCOL SYNOPSIS..................................................................................................................14
SCHEDULE OF ASSESSMENTS...................................................................................................28
INTRODUCTION.............................................................................................................................36
5.1
Phelan-McDermid Syndrome .....................................................................................................36
5.2
Current Treatments for Phelan-McDermid Syndrome................................................................37
5.3
Genetic Basis of Phelan-McDermid Syndrome..........................................................................37
5.4
Cellular Pathology in Phelan-McDermid Syndrome ..................................................................37
5.5
Scientific Rationale for use of NNZ-2591 in Phelan-McDermid Syndrome..............................37
5.6
Preclinical Data...........................................................................................................................38
5.6.1
Overview of Pharmacology and Toxicology Findings.........................................................38
5.6.2
Overview of Phelan-McDermid Mouse Model Findings .....................................................39
5.7
Clinical Data ...............................................................................................................................39
STUDY RATIONALE AND OBJECTIVES ..................................................................................41
6.1
Study Rationale...........................................................................................................................41
6.2
Rationale for Dose Selection and Route of Administration........................................................41
6.2.1
Rationale for Dose Selection ................................................................................................41
6.2.2
Rationale for Duration of Dosing .........................................................................................42
6.2.3
Rationale for Selection of Efficacy Outcomes .....................................................................42
6.3
Study Objectives and Endpoints................................................................................................. 43
6.3.1
Primary Objective.................................................................................................................43
6.3.2
Secondary Objectives ...........................................................................................................44
STUDY DESIGN ...............................................................................................................................46
7.1
Study Design Overview..............................................................................................................46
7.1.1
Study Design Diagram..........................................................................................................47
7.2
Dose-levels and Titration............................................................................................................47
7.2.1
Adjustment of the Dose for Tolerability...............................................................................47
7.2.2
Dose Escalation Review by the DSMC................................................................................48
7.3
Treatment Assignment................................................................................................................48
7.4
Study Timeline............................................................................................................................49
7.5
COVID-19 ..................................................................................................................................49
SUBJECT POPULATION ...............................................................................................................50
8.1
Inclusion Criteria ........................................................................................................................50
8.2
Exclusion Criteria .......................................................................................................................50
8.3
Abnormal Laboratory Findings ..................................................................................................54
8.4
Withdrawal Criteria ....................................................................................................................55
8.5
Risks and Benefits ......................................................................................................................55
STUDY PROCEDURES...................................................................................................................56

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9.1
Overview of Study Visits............................................................................................................56
9.2
Study Procedures by Visit...........................................................................................................57
9.2.1
Visit 1 Screening/Baseline (in-clinic) – Week -4 ( 2 days)................................................57
9.2.2
Visit 2 Screening/Baseline (telemedicine and in-home) – 2 Weeks from 
Visit 1 (±1 day).....................................................................................................................58
9.2.3
Visit 3 Baseline (in-clinic) – Week 0 (
2 days) ..................................................................59
9.2.4
Visit 4 Treatment Period (telemedicine and in-home) – Week 1 (
1 day)..........................60
9.2.5
Visit 5 Treatment Period (in-clinic) – Week 2 (
2 days) ....................................................61
9.2.6
Visit 6 Treatment Period (in-home nurse) – Week 3 ( 1 day).............................................61
9.2.7
Visit 7 Treatment Period (telemedicine and in-home) – Week 4 ( 1 day)...........................62
9.2.8
Visit 8 Treatment Period (in-home nurse) -Week 5 ( 1 day)...............................................63
9.2.9
Visit 9 Treatment Period (in-clinic) – Week 6 ( 2 days) ....................................................63
9.2.10
Visit 10 Treatment Period (in-home nurse) – Week 7 (
1 day)..........................................64
9.2.11
Visit 11 Treatment Period (telemedicine and in-home) – Week 8 (
1 day)........................65
9.2.12
Visit 12 Treatment Period ( in-home nurse) – Week 9 (
1 day) .........................................66
9.2.13
Visit 13 Treatment Period (telemedicine and in-home) -Week 10 ( 1 day) ........................66
9.2.14
Visit 14 Treatment Period – (in-home nurse) Week 11 ( 1 day).........................................67
9.2.15
Visit 15 Treatment Period (in-home nurse) – Week 12 (
day).........................................67
9.2.16
Visit 16 End of Treatment (in-clinic) – Week 13 (-3 days)..................................................68
9.2.17
Visit 17 Follow-up (telemedicine and in-home) – Week 15 (+ 4 days) ...............................69
9.3
Screening and Baseline Procedures ............................................................................................70
9.4
Treatment of Subjects .................................................................................................................71
9.4.1
Investigational Medicinal Product........................................................................................71
9.4.2
Investigational Medicinal Product Administration...............................................................71
9.4.3
Treatment Compliance .........................................................................................................72
9.4.4
Protocol Deviations ..............................................................................................................72
9.4.5
Early Discontinuation...........................................................................................................73
9.4.6
Concomitant Therapy ...........................................................................................................75
9.5
Assessments................................................................................................................................76
9.5.1
Vital Signs ............................................................................................................................76
9.5.2
Laboratory Tests...................................................................................................................77
9.5.3
Blood sample for biomarkers and stool sample for microbiome..........................................81
9.5.4
Medical/Clinical History ......................................................................................................81
9.5.5
Physical and Neurological Exam..........................................................................................82
9.5.6
................................................................................................................82
9.5.7
................................................................................................. 82
9.5.8
12-lead ECG and Stopping Criteria for Prolonged QT ........................................................83
9.5.9
Battery of Phelan-McDermid Syndrome Assessment Instruments ......................................84
9.5.10
Caregiver Diary ....................................................................................................................89
9.6
Pharmacokinetic Measurements ................................................................................................. 90
ADVERSE EVENTS.........................................................................................................................91
10.1 Definition of Adverse Event.......................................................................................................91
10.2 Definition of Serious Adverse Event..........................................................................................91

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10.3
.............................................................................................92
10.4 Adverse Reactions ......................................................................................................................92
10.5 Clinical Laboratory Abnormalities and Other Abnormal Assessments as AEs 
and SAEs ....................................................................................................................................92
10.6 Time Period, Frequency, and Method of Detecting AEs and SAEs...........................................92
10.7 Recording of AEs and SAEs.......................................................................................................93
10.8 Evaluating AEs and SAEs ..........................................................................................................93
10.8.1
Assessment of Intensity........................................................................................................93
10.8.2
Assessment of Causality.......................................................................................................93
10.8.3
Follow-up of AEs and SAEs ................................................................................................94
10.9 Prompt Reporting of the SAEs to the Sponsor ...........................................................................95
10.9.1
Completion and transmission of the SAE reports................................................................. 95
10.10 Deaths .........................................................................................................................................96
10.11
........................................96
10.12 Pregnancy ...................................................................................................................................97
STATISTICAL PLAN ......................................................................................................................98
11.1 Definitions ..................................................................................................................................98
11.1.1
Subject Populations ..............................................................................................................98
11.2 Sample Size Determination ........................................................................................................98
11.3 Safety Analyses...........................................................................................................................98
11.4 Efficacy Analysis........................................................................................................................99
11.5 Pharmacokinetic Analysis...........................................................................................................99
11.6 Biomarkers and Microbiome ......................................................................................................99
STUDY DRUG MANAGEMENT....................................................................................................99
12.1 Identity of Investigational Medicinal Product ............................................................................99
12.2 Management of Clinical Supplies.............................................................................................100
12.2.1
Drug Accountability ...........................................................................................................100
12.3 Overdose...................................................................................................................................101
QUALITY ASSURANCE AND DATA MANAGEMENT..........................................................102
13.1 Data Quality Assurance ............................................................................................................102
13.2 Case Report Forms....................................................................................................................102
13.3 Monitoring ................................................................................................................................102
13.4 Auditing ....................................................................................................................................103
13.5 Source Documents....................................................................................................................103
13.6 Protocol Deviations...................................................................................................................103
13.7 Records Retention.....................................................................................................................103
ETHICS ............................................................................................................................................105
14.1 Informed Consent .....................................................................................................................105
14.2 Institutional Review Board Approval.......................................................................................105
14.3 Additional Protections for Minors ............................................................................................106
STUDY MANAGEMENT ..............................................................................................................107
15.1 Principal Investigators ..............................................................................................................107
15.2 Data Safety Monitoring Committee..........................................................................................107

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15.3 Publications...............................................................................................................................107
ALLOMETRIC SCALING TO DETERMINE PHASE 2 
EXPOSURES...................................................................................................................................108
REFERENCES ................................................................................................................................112

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LIST OF TABLES 
Table 1 
Schedule of Assessments for Neu-2591-PMS ................................................. 28 
Table 2 
Pharmacokinetic Blood Sampling Schedule (Subjects 
Ages 7 to 12 Years Old) ................................................................................... 34 
Table 3 
Pharmacokinetic Blood Sampling Schedule (Subjects 
Ages 3 to <7 Years Old) ................................................................................... 35 
Table 4 
Dose Titration Schedule .................................................................................. 47 
 
LIST OF FIGURES 
Figure 1 
Neu-2591-PMS-001 Study Design Diagram ................................................... 47 
 
 
 

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LIST OF ABBREVIATIONS
AAC
Augmentative and alternative communication
ABC-2
Aberrant Behavior Checklist-2
AE
Adverse event
ALP
Alkaline phosphatase
ALT
Alanine amino transferase
AMSE
Autism Mental Status Exam
APTT
Activated Partial Thromboplastin
ASD
Autism Spectrum Disorder
AST
Aspartate transaminase
AUC
Area under (concentration-time) curve to last time point
AUCinf
Area under (concentration-time) curve from time zero extrapolated to infinite time
AUC0-24
Area under (concentration-time) curve from time 0 to 24 hours at steady state
AUCtau
Area under (concentration-time) curve from time zero to the end of the dosing 
interval
BID
Twice daily
BP
BPI-SF
Blood pressure
Behavior Problems Inventory-Short Form
bpm
Beats per minute
BR
Bilirubin
BUN
Blood urea nitrogen
CAS
Chemical Abstracts Service
CBC
Complete Blood Count
CBD
Cannabidiol
CDKL5
Cyclin-dependent kinase-like 5
CFR
Code of Federal Regulations
CGI-I
Clinical Global Impression Scale – Improvement
CGI-S
Clinical Global Impression – Severity
cGP
Cyclic Glycine-Proline
CKD
Chronic kidney disease
CLss/F
Apparent total body clearance after oral administration, steady state
CLtv
True population value for clearance of the drug
Cmax
The maximum observed blood concentration
CMP
Comprehensive metabolic panel
COVID-19
Coronavirus disease 2019
CSHQ
Child Sleep Habits Questionnaire
Css
Concentration at steady-state 
Ct
Concentration at the last measurable time point
C
Concentration at the end of the dosing interval
°C
Degree(s) centigrade
CVA
Costovertebral angle tenderness

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DBP 
Diastolic blood pressure 
dL 
Deciliter 
DNA 
Deoxyribonucleic acid 
DSM-5 
Diagnostic and Statistical Manual of Mental Disorders, 5th Edition 
DSMC 
Data Safety Monitoring Committee 
DQ 
Development quotient 
EC 
Expressive communication 
ECG 
Electrocardiogram 
eCRF 
Electronic case report form 
EDC 
Electronic Data Capture System 
EL 
Expressive language 
eGFR 
Estimated glomerular filtration rate 
EOT 
End of Treatment 
FDA 
Food and Drug Administration 
FM 
Fine motor 
FR 
Fluid reasoning 
FSIQ 
Full scale intellectual quotient  
g 
gram 
GCP 
Good clinical practice 
GGT 
Gamma-glutamyl transferase 
GERD 
Gastroesophageal reflux disease 
GI 
Gastrointestinal 
GIHQ 
Gastrointestinal Health Questionnaire 
GM 
Gross motor 
GMP 
Good manufacturing practice 
GRAS 
Generally Recognized as Safe 
GSV 
Growth scale values 
Hb 
Hemoglobin 
HbA1C 
Glycated (or glycosylated) hemoglobin 
Hct 
Hematocrit 
HDPE 
High-density polyethylene 
hr, hrs 
Hour, hours 
HPF 
High power field 
HTN 
Hypertension 
IB 
Investigator’s brochure 
ICH 
International Council for Harmonisation 
ICMJE 
International Committee of Medical Journal Editors 
ICND 
Impact of Childhood Neurological Disability Scale 
IGF-1 
Insulin-Like Growth Factor 1 
IND 
Investigational new drug 
IMP 
Investigational Medicinal Product 
IQ 
Intelligence quotient 
IRB 
Institutional review board 
ITT 
Intent to treat 
IUD 
Intrauterine device 

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kg  
Kilogram 
 
 
KN 
Knowledge 
KO 
Knock-out 
L 
Liter 
m  
Meter 
MAO 
Monoamine oxidase 
MB-CDI 
MacArthur-Bates Communicative Development Inventory 
MCH 
Mean cell hemoglobin 
MCHC 
Mean cell hemoglobin concentration 
MCV 
Mean cell volume 
MDMA 
Methylenedioxymethamphetamine 
MedDRA 
Medical Dictionary of Regulatory Activities 
mEq 
Milliequivalent 
mg 
Milligram 
MIS-C 
Multisystem Inflammatory Syndrome in Children 
mL 
Milliliter 
mmol/L 
Millimole per liter 
ms 
Millisecond 
Mullen 
Mullen Scales of Early Learning 
N 
Number of subjects 
NCA 
Non-compartmental analysis 
NDD 
Neurodevelopmental disorder 
NHANES 
National Health and Nutrition Examination Survey 
NHS 
Natural History Study 
NOAEL 
No adverse effect level 
NVIQ 
Nonverbal IQ 
ORCA 
Observer-Reported Communication Ability 
OTC 
Over-the-counter 
PK 
Pharmacokinetic 
PLT 
Platelets 
PMS 
Phelan-McDermid syndrome 
PMSF 
Phelan-McDermid Syndrome Foundation 
 
 
popPK 
Population Pharmacokinetics 
PP 
Per protocol 
QI-Disability 
Quality of Life Inventory-Disability 
QR 
Quantitative reasoning 
QTcF 
Fridericia’s correction factor for QT 
RBC 
Red blood cell count 
RDW, 
RDW,CV 
Red cell distribution width 
RL 
Receptive language 
SAE 
Serious adverse event 
SAER 
Serious adverse event report 

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SAP 
Statistical analysis plan 
SARS-CoV-2 
Severe acute respiratory syndrome coronavirus 
SBP 
Systolic blood pressure 
SB5 
Stanford-Binet Intelligence Scales version 5 
t1/2 
Terminal elimination half-life 
T3 
Triiodothyronine 
T4 
Thyroxine 
TEAE 
Treatment emergent adverse event 
THC 
Tetrahydrocannabinol  
Tmax 
Time to maximal concentration 
TSH 
Thyroid stimulating hormone 
µmol 
Micromole 
UA 
Urinalysis 
UK 
United Kingdom 
ULN 
Upper limit of normal 
US 
United States 
VIQ 
Verbal intelligence quotient 
VR 
Visual reception 
VS 
Visual-spatial 
WBC 
White blood cell count 
WM 
Working memory 
WTcentered 
Population value for the weight in the adult population corresponding to the derived 
CLTV 

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Protocol Neu-2591-PMS-001:  Pediatric Safety, Tolerability, and Pharmacokinetic Study 
assessed for study eligibility. Rescreening of subjects is allowable under 
certain circumstances with the approval of the Sponsor and Medical Monitor.  
 
During the Screening/Baseline period data will also be collected to establish 
the subject’s baseline characteristics and symptom severity based on 
assessments collected during the 4 to 6 week period. There are two in-clinic 
visits and one remote/in-home visit during the Screening and Baseline period 
(Visits 1, 2, 3).  
 
Once eligibility is confirmed, subjects will be dosed at a starting dose of 4 
mg/kg twice daily (BID) and up-titrated to a target dose of 12 mg/kg BID of 
orally administered NNZ-2591.  The mg/kg dosing is based on the subject’s 
weight at Baseline (Visit 3). Subjects will receive treatment with NNZ-2591 
for a total of 13 weeks. During the treatment period there are three in-clinic 
visits: Week 2 (Visit 5), Week 6 (Visit 9) and Week 13 (Visit 16). There is a 
remote visit by the Investigator via telemedicine and a same-day in-home 
visit by a visiting nurse at Week 1, Week 4, Week 8, and Week 10. 
Additionally, there are in-home visits by a visiting nurse at Week 3, Week 5, 
Week 7, Week 9, Week 11, and Week 12. 
 
All subjects will have a combined remote follow-up visit with the 
Investigator via telemedicine and an in-person home visit by a visiting nurse 
approximately 2 weeks after the end of treatment (Week 15, Visit 17). 
 
For all visits designated as in-clinic, an in-person visit is preferred. All 
requests for off-site assessments due to extenuating circumstances related to 
the Coronavirus disease (COVID-19) health emergency must be approved by 
the Sponsor or Medical Monitor in advance. 
 
Enrollment Groups 
For enrollment, the subjects will be divided into three groups by age: 9–12-
year-olds (Group 1), 6–8-year-olds (Group 2), and 3–5-year-olds (Group 3). 
Enrollment will commence in the oldest age group (Group 1). After at least 
three subjects in Group 1 have received two weeks of treatment with the IMP 
at the starting dose (4 mg/kg BID), safety and tolerability data will be 
reviewed by the Data Safety Monitoring Committee (DSMC). If tolerability 
and safety data are deemed acceptable, enrollment for Group 2 will proceed 
and dosing will begin at the starting dose. When at least three subjects in 
Group 2 have received two weeks of treatment at the starting dose, safety and 
tolerability data will be reviewed by the DSMC. If tolerability and safety data 
for Group 2 are deemed acceptable, enrollment for Group 3 will commence 
and dosing will begin at the starting dose. 
COVID-19  
As a result of the COVID-19 public health emergency, this protocol includes 
provision for alternative methods of performing safety and efficacy 
assessments in accordance with the FDA Guidance on Conduct of Clinical 

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Protocol Neu-2591-PMS-001:  Pediatric Safety, Tolerability, and Pharmacokinetic Study 
Trials of Medical Products during the COVID-19 Public Health Emergency. * 
Provision is made for off-site assessments where necessary, and all efforts 
have been made to ensure the alternative processes are consistent as much as 
possible with in-clinic visits. For visits that are designated as in-clinic, an 
actual in-clinic visit is preferred. However, an in-home/remote visit may be 
conducted for a scheduled in-clinic visit with the prior approval of the 
Sponsor and Medical Monitor. Clinical investigators are to document the 
reason for any contingency measures implemented. If at any time in the 
study, the subject or his or her caregiver tests positive for severe acute 
respiratory syndrome coronavirus 2 (SARS-CoV-2) or becomes ill with 
symptoms of COVID-19, the family should be instructed to contact the site as 
soon as possible. Once informed, the Investigator should contact the Medical 
Monitor. 
Study Population 
Approximately 20 male and female subjects between the ages of 3 and 12 
years, inclusive, are planned to complete the study.  
The subjects will be categorized by age in three groups: 9- to 12-year-olds 
(Group 1), 6- to 8-year-olds (Group 2), and 3- to 5-year-olds (Group 3). 
Enrollment will be balanced to the extent possible by sex and age with a 
minimum of 3 males and 3 females across all age groups, and a minimum of 
three subjects in each age group.  
Inclusion Criteria 
To be eligible for this study, subjects must meet all of the inclusion criteria 
and none of the exclusion criteria. The inclusion criteria include: 
1. Clinical diagnosis of PMS with a documented disease-causing 
genetic abnormality of SHANK3.   
2. Males or females ages 3 to 12 years at Screening, inclusive.  
3. Body weight of 12 kg or higher at Screening. Weight measurements 
may be repeated during the Screening period in consultation with the 
Medical Monitor. 
4. Subjects with a Clinical Global Impression – Severity (CGI-S) score 
of 3 or greater at the Screening visit. 
5. Not actively undergoing regression or loss of skills, defined as no 
persistent loss of previously acquired developmental skills for a 
period within 3 months of the Screening visit. 
 
 
* FDA Guidance on Conduct of Clinical Trials of Medical Products During the COVID-19 Public Health 
Emergency: Guidance for Industry, Investigators, and Institutional Review Boards (Center for Biologics 
Evaluation and Research; Center for Devices and Radiological Health; Center for Drug Evaluation and 
Research; Office of the Commissioner; Office of Clinical Policy and Programs; Office of Clinical Policy; Office 
of Good Clinical Practice) (2021). 

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Protocol Neu-2591-PMS-001:  Pediatric Safety, Tolerability, and Pharmacokinetic Study 
a. Previously acquired skills include any skill established and 
used on a daily basis for at least 3 months. 
b. Variations in use of skills that is part of a general pattern of 
ups and downs, as determined by the Investigator, are not 
counted as regression. 
c. Skills may include language, non-verbal communication, 
fine motor skills, ambulation (including gait, coordination, 
independence of walking/standing), social skills, play, self-
help.  
6. Each subject must be able to swallow the IMP provided as a liquid 
solution.  
7. The subject’s caregiver(s) must have sufficient English language 
skills to complete caregiver assessments in English. 
Exclusion Criteria 
To be eligible for this study, subjects must meet all of the inclusion criteria 
and none of the exclusion criteria. Exclusion criteria include: 
Laboratory and Screening Values 
1. Body weight < 12 kg at Screening. Weight may be repeated during 
the Screening period in consultation with the Medical Monitor. 
2. HbA1c values above 7% at the Screening visit. 
3. Clinically significant abnormalities (as determined by the 
Investigator) in safety laboratory values, or vital signs, as measured 
at the Screening visit. Laboratory testing may be repeated during the 
Screening period in consultation with the Medical Monitor. 
4. Positive pregnancy test at the Screening visit. 
5. QTcF Exclusions (any of the following): 
a. Screening QTcF interval of >450 ms assessed using 
Fridericia’s correction factor based on 12-lead 
electrocardiogram (ECG) obtained as a continuous ECG of at 
least 50 seconds. 
b. Hypokalemia (Serum potassium at the Screening visit <3.0 
mmol/L or mEq/L). Serum potassium may be repeated 
during the Screening period with the agreement of the 
Medical Monitor. 
c. QTcF prolongation that is currently controlled with 
medication, in which normal QTcF intervals can only be 
achieved with medication. 
6. Any other clinically significant finding (as determined by the 
Investigator) on ECG at the Screening visit that would increase the 
likelihood of a severe arrhythmia. 
 
COVID-19 
  
7. Positive for SARS-CoV-2 at Screening or Baseline. 
8. Previous COVID-19 infection within the last 12 months that required 
admission to the hospital. 

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Protocol Neu-2591-PMS-001:  Pediatric Safety, Tolerability, and Pharmacokinetic Study 
9. Previous COVD-19 infection involving multi-organ systems, 
resulting in Multisystem Inflammatory Syndrome in Children 
(MIS-C) or with clinically significant sequelae. 
10. COVID-19 infection associated with acute kidney injury (AKI) or 
renal manifestations (e.g. proteinuria, hematuria, echogenic kidneys). 
 
 
 
 
 
  
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Concomitant Treatments 
 
28. Current treatment or treatment within the two weeks prior to start of 
Screening with MAO inhibitors, d-cycloserine, oxytocin, carbetocin, 
tricyclic antidepressants, bupropion. 
29. Current treatment with more than 3 allowable psychotropic 
medications.   
a. Includes medications used to treat problems with sleep onset 
and sleep continuity except melatonin. Melatonin for 
difficulties with sleep onset is permissible and is not included 
in the count of psychotropic medications.   
b. The use of anti-epileptics for other indications such as the 
treatment of mood disorders counts toward the limit of 
permitted psychotropic medications.   
c. Anti-epileptic medications used for treatment of seizures 
does not count towards the limit of psychotropic 
medications.  
30. Current treatment with insulin or treatment within the last 12 weeks 
prior to commencement of IMP 
31. Current treatment with insulin-like growth factor 1 (IGF-1) or 
treatment within 6 months of commencement of the IMP. 
32. Current treatment with growth hormone or treatment within 
12 months of commencement of the IMP. 
33. Non-pharmacologic somatic treatment (e.g., a ketogenic diet or vagal 
nerve stimulation) whose dosing regimen has not been stable at least 
4 weeks prior to start of Screening. If the treatment was discontinued, 
the discontinuation must have occurred no fewer than 2 weeks before 
start of Screening.  
34. Subjects planning to start a new behavioral, educational, or cognitive 
therapy during the period of the study or those who have begun a 
new behavioral or cognitive therapy regimen within 4 weeks prior to 
start of Screening.  
a. Note: changes to an ongoing treatment regimen that are due 
to school schedules or are otherwise seasonally related are 
not exclusionary as long as changes are consistent with their 
typical type and pattern of behavioral treatment.  
35. Seizure medication whose dosing regimen is not stable 8 weeks prior 
to commencing IMP. Adjustments for changes in weight or age are 
allowable. If the treatment was discontinued, the discontinuation 
must have occurred no fewer than 2 weeks before start of Screening. 
36. Psychotropic medications or any other medication used for a chronic 
illness (not including antibiotics, pain relievers, anti-diarrheals, and 
laxatives) whose doses and dosing regimen have not been stable for 
at least 4 weeks prior to start of Screening. If the treatment was 
discontinued, the discontinuation must have occurred no fewer than 
2 weeks before the start of Screening. 
a. This includes nutraceutical treatments and cannabinoids 
(tetrahydrocannabinol [THC] and cannabidiol [CBD]) which 
are allowable but also must meet the stability conditions 
above. 

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b. Pain relievers, laxatives, and anti-diarrheals may be used as 
needed. 
c. Standard of care immunizations and vaccinations (including 
COVID-19) are allowed and are not subject to the above 
stability conditions. 
d. The Investigator should consult with the medical monitor if a 
subject is being treated with ocular toxic, hepatotoxic, 
nephrotoxic, or antibiotic medications.  
e. If the Investigator is unsure if a medication is permitted, the 
Medical Monitor should confirm if the medication is allowed 
and will provide written documentation to support the use of 
the medication, if allowed.  
 
Regression of Skills 
37. Actively undergoing regression or loss of skills defined as a 
persistent loss of previously acquired developmental skills within 
3 months of the start of Screening.  
a. Previously acquired skills include any skill established and 
used on a daily basis for at least 3 months. 
b. Variations in use of skills that is part of a general pattern of 
ups and downs (as determined by the Investigator) are not 
counted as regression. 
c. Skills may include language, non-verbal communication, 
fine motor skills, ambulation (including gait, coordination, 
independence of walking/standing), social skills, play, self-
help.  
 
Seizures 
 
38. Seizure profile that is not stable 8 weeks prior to commencing IMP. 
The overall pattern of seizure activity for the subject should be 
consistent with their typical pattern of seizures and be stable within 
the 8-week period in terms of type, intensity, duration, and frequency 
as determined by the clinical Investigator.  
 
Medical Conditions 
39. Currently pregnant, lactating, or breastfeeding. 
40. Current clinically significant (as determined by the Investigator) 
cardiovascular, gastrointestinal, respiratory, or endocrine disease, or 
clinically significant organ impairment. The Investigator may consult 
with the Medical Monitor as needed if he/she is uncertain if 
symptoms are exclusionary. 
41. Current clinically significant (as determined by the Investigator) 
hypo- or hyperthyroidism. If the subject has hypo- or 
hyperthyroidism that is controlled with medication, the Investigator 

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should consult with the Medical Monitor to determine if the subject 
is eligible.  
42. Type 1 or Type 2 diabetes mellitus requiring insulin (whether well 
controlled or uncontrolled), or uncontrolled Type 1 or Type 2 
diabetes.  
43. Has planned surgery during the study. 
44. History of, or current, cerebrovascular disease or brain trauma. 
45. History of, or current catatonia or catatonia-like symptoms. 
46. History of, or current, malignancy. 
47. Current major or persistent depressive disorder (including bipolar 
depression). 
48. Significant uncorrected hearing impairment. 
 
Other Criteria 
49. Allergy to strawberry. 
50. The subject is unable to take the IMP orally and swallow the IMP 
provided as a liquid solution. Administration of the IMP by 
nasogastric tube, feeding tube, thickened liquid, or gastrostomy tube 
is not allowed. 
51. Has participated in another interventional clinical study within 30 
days prior to start of Screening  
52. Prior enrollment in this clinical trial.  
a. Individuals who leave the study during the Screening period 
and have not entered the study may be able to rescreen 
pending review and approval of the Sponsor and Medical 
Monitor.  
b. Individuals who were deemed eligible and entered the study 
(enrolled) who discontinue the study may not re-enroll in the 
study.  
53. The subject is judged by the Investigator or the Medical Monitor to 
be inappropriate for the study for any reason. 
 
Investigational Product 
NNZ-2591 Oral Solution, 50mg/mL will be administered open-label at the 
target dose of 12 mg/kg BID. The mg/kg dosing is based on the subject’s 
weight at Baseline (Visit 3). Subjects will be up-titrated to the target dose as 
outlined in the table below.  
 
 
 
 
 

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following Baseline, vital signs (except height) should be collected before the 
dose is administered. Day 1 of dosing is defined by the date when the first 
dose is taken. At this visit, the site will provide IMP for the caregiver to 
dispense at home. Enough IMP will be provided to cover the interval until the 
next in-clinic visit when the caregiver will be re-supplied from the site. 
 
The protocol includes procedures for dose titration and dose adjustments, if 
any are necessary (Section 7.2), and pre-specified stopping criteria (i.e., 
discontinuation of IMP) consistent with the exclusion criteria, including 
QTcF, renal, ocular, and hepatic, exclusion criteria (Section 9.4.5). 
Endpoints 
Primary Endpoints  
 
Safety: 
The incidence of AEs and SAEs from commencement of IMP administration 
through to the time of the last study visit will be evaluated. Vital signs, 
laboratory measures, urine output history, physical exam results 
(neurological, ophthalmologic, and general), 
findings, and 
ECGs will also be evaluated from screening/baseline through the end of the 
study.  
 
Tolerability will be assessed based on caregiver reports and the Caregiver 
Diary, required dosing adjustments or discontinuations, dosing compliance, 
and AEs related to subject experience. 
 
Pharmacokinetics: 
Pharmacokinetic blood samples will be collected according to the age 
appropriate sampling schedule for each subject (See Tables 2 and 3). 
Pharmacokinetic concentrations and exposure parameters for NNZ-2591 will 
be derived by sparse non-compartmental analysis (NCA), and may include 
maximum concentration (Cmax), area under the concentration-time curve 
from time 0 to the end of the dosing period (AUCtau), and other parameters. 
Secondary Endpoints: 
 
Efficacy: 
Within-subject changes will be assessed from the Baseline period to end of 
treatment. 
 
Overall Improvement 
o PMS-specific Clinical Global Impression Scale–Improvement 
(CGI-I), Overall Improvement Scores; clinician-assessed 
o PMS-specific Clinical Global Impression Scale – Domain 
Improvement Scores; clinician-assessed 
o Caregiver Global Impression – Change Scores; caregiver-
assessed 
 
 
 
 
 

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deviation is larger, the size of the detectable difference would also be larger. 
For example, if the standard deviation is 1.5, the detectable difference for a 
power of 0.80, 0.85, and 0.90 is 1.02, 1.09, and 1.18 or larger, respectively. 
Statistical Methods 
Safety  
Adverse events and other safety data will be summarized as frequencies and 
percentages, described in terms of severity and potential attribution. 
Objective safety assessments will be summarized over time on study; shift 
tables at time points of interest may be generated.  Details of the safety 
analyses will be specified in the SAP. 
 
Efficacy 
Efficacy will be assessed by looking at within-subject changes from the 
Baseline period to the EOT. The subject’s baseline characteristics and 
symptom severity will be established based on assessments collected during 
the 4 to 6 week Screening/Baseline period. Baseline values will be based on 
the average values of Visits 1, 2 and 3 for assessments collected at more than 
one visit. A Wilcoxon signed rank test will be used to test for improvement 
and a significance level will be computed.  
 
Potentially influential factors will be considered and addressed with a linear 
regression model. This model may include covariates such as age, sex, NVIQ 
or NVIQ equivalent, genotype, history of regression (yes/no), ASD diagnosis 
yes/no with no more than two covariates included in any model. Descriptive 
statistics and corresponding graphics will be used to present the results. The 
efficacy analysis details will be specified in the SAP. 
 
Pharmacokinetics: 
NNZ-2591 PK concentrations will be listed by subject and time point for 
each dose level with actual time they were acquired. The concentrations will 
be summarized by time, dose level and age group. For the concentrations 
measured at trough points dose relationship will be examined statistically 
with age group and/or body weight of patient as covariate. 
Overall exposure parameters for NNZ-2591 such as Cmax and AUCtau may be 
derived by sparse non-compartmental analysis (NCA). Additionally, PK 
concentrations of NNZ-2591 measured in pediatric patients will be used to 
refine a population PK model developed from adult NNZ-2591 PK data and 
extrapolated to the pediatric population. After refinement, complete profiles 
for each patient will be simulated using range of variability of model 
parameters and individual covariate effects. A standard NCA approach will 
be used for simulated profiles to calculate parameters Cmax, AUCtau, etc. for 
characterization of NNZ-2591 exposure in pediatric patients. 
The PK analysis details will be specified in the PK Statistical Analysis Plan 
(PK SAP). 
 

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Biomarkers and Microbiome: 
Biomarker analysis will be detailed in a separate analysis plan and will not 
include DNA sequencing. 
 
Microbiome analysis will be described in a separate analysis plan. 
 
Trial Sites 
Approximately 4 to 7 sites in the US. 

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X = Conducted by site personnel or caregiver as applicable 
N = Conducted by visiting nurse 
Abbreviations: ABC-2=Aberrant Behavior Checklist-2; AE=adverse event; BPI-SF=Behavior Problems Inventory-Short Form; CBC=Complete 
Blood Count; CGI-I=Clinical Global Impression Scale-Improvement; CGI-S=Clinical Global Impression Scale-Severity; CMP=Comprehensive 
Metabolic Panel; CSHQ=Child Sleep Habits Questionnaire; DSM-5=Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; ECG = 
electrocardiogram; EOT=end of treatment; GIHQ=GI Health Questionnaire; ICND=Impact of Childhood Neurological Disability; 
IMP=Investigational Medicinal Product; MB-CDI=MacArthur-Bates Communicative Development Inventory; ORCA=Observer-Reported 
Communication Assessment; PK = pharmacokinetic; PMS=Phelan-McDermid syndrome; PMS-DSRS=PMS Clinician Domain Specific Rating 
Scale; QI-Disability=Quality of Life Inventory- Disability; SAE=serious adverse events; Stanford Binet Intelligence Scales ver 5; T3 = 
triiodothyronine; T4 = thyroxine; TSH = thyroid stimulating hormone.   
 
a No assessments can be conducted until after informed consent has been given by the caregiver or legally authorized representative. Training for 
the caregivers on all caregiver completed assessments must be done before the caregiver/rater may complete the assessments. The 
Screening/Baseline period will be conducted over 4 to 6 weeks. The second visit during the Screening/Baseline period (Visit 2) should be 
conducted 2 weeks 
day after the Screening visit (Visit 1). The subject will then remain in Screening for an additional 2 to 4 weeks. The 
caregiver diary must be completed daily during the entire Screening/Baseline period whether it is 4 weeks or 6 weeks. The Screening visit (Visit 1) 
and Baseline visit (Visit 3) may be conducted over three consecutive days. It is preferrable that ECGs, safety labs and biomarker sample collection 
are conducted on the same day. All assessments must be completed within the window for the visit (visit day ± 2 days). For Visit 3, all 
assessments must be completed before administration of the IMP. 
 
b The End of Treatment visit is conducted when the subject is still on IMP treatment. For early termination, in addition to study completers, 
subjects who have received IMP for longer than 2 weeks and discontinue prematurely any time after Visit 5 should return to the investigational site 
for final safety and efficacy assessments as scheduled for the EOT visit (Visit 16) and complete the study exit form. 
c At Visit 3, the first dose of IMP will be administered in the clinic after all Baseline assessments are completed, or, if the Investigator judges that 
it is too late in the day, on the following day. The subject should be monitored for at least three hours post first dose. If the first dose is 
administered the day following Baseline, vital signs (except height) should be collected before the dose is administered. Day 1 of dosing is defined 
by the date when the first dose is taken. At the Baseline visit, the site will dispense an adequate supply of IMP for dispensing by the caregiver at 
home. Dosing at the end of Baseline counts as Day 1 whether one or two doses are given. Dosing may not exceed 91 days including Day 1, and all 
efficacy assessments for the EOT visit must be completed on or before Day 91 of treatment. 
 
d A clinic visit is preferred but an off-site visit may be conducted for a scheduled in-clinic visit in extenuating circumstances due to the COVID-19 
health crisis. All requests for off-site visit assessments due to extenuating circumstances must be approved in advance by the Sponsor or Medical 
Monitor. The in-clinic visits may be conducted over three consecutive days. All assessments including caregiver-completed assessments must be 
done within the window for the visit. 
 

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e This is a combined remote and in-person nurse visit. The remote visit is conducted by the site via telemedicine or video facilities as appropriate. 
Any caregiver-completed assessments should be completed the same day of the visit or no earlier than the day before the visit (except the 
Caregiver Diary which is completed daily) and reviewed by the Investigator. A modified version of the physical and neurological exam will be 
done at the remote visits based on the guidance document provided to the Investigator. At Week 4, the site should confirm with the caregiver that 
the child has started the new dose if they were approved for dose titration. These combination remote/in-home visits will be conducted 
simultaneously whenever possible, or they will ideally be conducted on the same day. If that is not possible, the telemedicine visit and the nurse 
visit may be conducted over two consecutive days. If that is not possible, the telemedicine visit and the nurse visit may be conducted over two 
consecutive days. A combined remote visit may be conducted in-clinic by the study staff if agreed upon by the Investigator and the caregiver. See 
Section 9.1 and Section 9.2. 
 
f In-home visits will be conducted by a visiting nurse. At every nurse visit, the nurse will collect urine, vital signs including weight, and blood 
samples for a comprehensive metabolic panel (CMP).  The nurse will also conduct a targeted physical exam assessing general appearance, 
abdominal/CVA tenderness, and edema. A suprapubic exam (bladder palpation) to assess for urinary retention may be performed.  The visiting 
nurse will also review the dosing diary, query oral intake, and do a review of tolerability. Blood samples for CBC with differential and coagulation 
will be collected at Weeks 4, 8, 10 and Week 15 (indicated by “N” in the Schedule of Assessments). At the post-treatment follow-up visit at Week 
15, the visiting nurse will also collect ECG, in addition to the above assessments. At Week 7, the site will also have a phone call with the caregiver 
to confirm that the child has started the new dose if they were approved for dose titration.  The site will confirm the visiting nurse has been 
informed so the dosing schedule can be reviewed with the family during the in-home visit. A nurse-only in-home visit may be conducted in-clinic 
by the study staff if agreed upon by the Investigator and the caregiver. See Section 9.1 and Section 9.2.  
g  The in-clinic physical exam will include an abdominal exam and an assessment of CVA. A suprapubic exam (bladder palpation) to assess for 
urinary retention may be performed.  General awareness will be captured as part of the neurological exam. For in-home nursing visits, the nurse 
will do a Targeted Physical exam assessing general appearance (e.g., alertness), an abdominal/CVA, and edema. A suprapubic exam (bladder 
palpation) to assess for urinary retention may be performed.  
 
h A modified version of the neurological and physical exam will be done for the remote visit based on the guidance document provided to the 
Investigator.  
 
i
 
 
j The visiting nurse will query any changes in tolerability during the in-home visit. Any changes will be noted and provided to the Investigator. The 
Investigator will also query changes in tolerability and note any changes in the remote assessment. The Investigator is responsible for determining 
and reporting any changes that qualify as Adverse Events. 
 
k The caregiver fills out the diary daily from the first day of screening through two weeks after the EOT Visit. X denotes review of the Caregiver 
Diary including the daily summary log, medication log, non-medicinal treatments log, seizure log and new/changes in symptoms log. All visits: 

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The Investigator (or appropriately credentialed designee) is responsible for reviewing for ALL visits. In-home visits: At the in-home nurse visit, 
the nurse will review the Caregiver Diary to flag and check any issues that could be reported as AEs. The nurse will notify the site about any 
urgent issues the day of the visit and note anything else in the source documents. The nurse does not sign the diary. The source documents and the 
diary will be sent to the site. The Investigator (or appropriately credentialed designee) will review the diary and source documents collected at the 
in-home visit. 
Note: There are two rows for Caregiver Diary review procedures (to emphasize the importance of thorough and complete dosing 
documentation): this row (Caregiver Diary) denotes that the caregiver fills out the diary daily and a designated clinician reviews it for 
safety/tolerability; a second row (Review dosing compliance documentation in diary, see footnote “l”) is intended to ensure that the 
caregiver is administering IMP/documenting dose properly in the Caregiver Diary. 
 
l The daily dosing log in the Caregiver Diary will be reviewed at all post-baseline visits through EOT. If any doses are missed or mis-dosed, this 
should be queried with the caregiver and appropriate feedback given to the family. This feedback should be documented in the source documents.  
At the in-home nurse visit, the nurse will review the caregiver diary to check any issues and provide feedback to the family at the visit. The nurse 
will notify the site about any urgent issues the day of the visit and note anything else in the source documents. The nurse does not sign the daily 
dosing log/summary page. The source documents and the diary will be sent to the site. The Investigator (or appropriately credentialed delegee) 
will review the diary and source documents collected at the in-home visit. 
 
m Coagulation includes prothrombin time, activated partial thromboplastin (aPTT), and international normalized ratio (INR). 
 
n A Comprehensive Metabolic Panel will be assessed every post-enrollment visit (see Section 9.5.2). If abnormal findings are observed on renal or 
liver function tests, additional tests as is clinically indicated may be conducted as described in Sections 9.5.2.1 and 9.5.2.3). 
 
o Both urinalysis and a urine screen for drugs of abuse will be evaluated at Screening (See Section 9.5.2). 
 
p For female subjects who have reached menarche. 
 
q See Table 2 and Table 3 for PK blood collection times. 
 
r The Mullen is done for subjects who cannot obtain basal on SB5 or for whom the SB5 is developmentally inappropriate. 
 
s The study exit form should also be completed if the subject terminates the study early. 
 
 

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Table 2 
Pharmacokinetic Blood Sampling Schedule (Subjects Ages 7 to 12 Years Old) 
Week 
Visit 
No. 
Treatment  
Timing of Sample  
(relative to start of dosing)a 
Sample Time 
Point 
2 
5 
  
Pre dose (-120 to -15 minutes)b 
1 
  
  
  
1-3 hours post dosec 
2 
 
 
 
4-7 hours post dosec 
3 
6 
9 
Mid-treatment 
Pre dose (-120 to -15 minutes) b 
4 
  
  
 
1-3 hours post dosec 
5 
  
  
 
4-7 hours post dosec 
6 
13 
16 
End of Treatment  
Pre dose (-120 to -15 minutes)b 
7 
  
  
  
1-3 hours post dosec 
8 
  
  
  
4-7 hours post dosec 
9 
a All post-dose windows are determined from the first dose of the visit (morning dose) and all PK samples must be 
collected before the second dose (PM dose).  
 
 
b Pre dose counts as both T0 and 12 hours post dose from previous evening (near trough). The previous evening’s 
dose should be taken in the evening as late as possible, preferably before bedtime. 
 
c Post-dose sample collection can be +/- 15 minutes of the target time and must be at least 30 minutes from the 
previous sample (samples can be no closer than 30 minutes apart). The actual collection time must be recorded. 
 

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INTRODUCTION
5.1
Phelan-McDermid Syndrome
Phelan-McDermid syndrome (PMS, also referred to as 22q13 Deletion Syndrome) is a rare genetic 
neurodevelopmental disorder characterized by neonatal hypotonia, global developmental delay, absent 
speech/severe speech impediments, and moderate to profound intellectual disability.2-5  
Phelan-McDermid syndrome is caused by a deletion or other structural change to the terminal end of 
chromosome 22 in the 22q13 region, or a disease-causing mutation of the SHANK3 gene.6 SHANK3 is a 
synaptic scaffolding protein expressed in the postsynaptic density (PSD) of excitatory synapses. 
Heterozygous deletions or point mutations of SHANK3 are thought to be the main cause of the 
neurodevelopmental features of PMS.7-9 Most cases are caused by deletions10, 11 which may include 
terminal deletions and interstitial deletions. Loss of function can also be precipitated by translocations, 
ring chromosomes, and duplications.10 This variable range of genetic changes gives rise to a wide range 
of medical, intellectual, and behavioral challenges.
The majority of cases of PMS occur spontaneously (de novo),12, 13 while 15-20% of cases are inherited 
from a parent who carries the chromosomal abnormality.14, 15  
Most affected individuals have moderate to profound intellectual disability and severe speech 
impairments or lack of speech.4, 5, 9, 16-18 They usually have low to very low adaptive behavior skills for 
daily living, reporting in <10th percentile,7, 19-21 and severe language impairments, with about half of these 
individuals remaining nonverbal.7, 9, 10, 15, 16, 20, 22-24  
Other difficulties for individuals with PMS include fine and gross motor deficits with delays in motor 
milestones, impairments in motor coordination, and gait abnormalities including toe walking, ataxic gait 
and steppage gait.4, 7, 12, 16, 18, 25 Hypotonia is also a key feature of PMS, which affects early motor 
development, feeding, and postural control.4, 26  
Individuals with PMS are medically complex and present with a number of medical issues. Structural 
brain abnormalities are frequently present,9 and arachnoid cysts occur more frequently (15%) than in the 
general population (1%).2, 9 Individuals with PMS also have a higher rate of congenital heart defects.3, 9
Seizures occur in approximately 40-60% of affected individuals,3, 26-28 and approximately 40% of 
individuals with PMS are reported to have sleep problems.16, 26, 29, 30 Catatonia symptoms have been 
observed in up to 53% of adults and adolescents with PMS.31 Additionally, a decreased perception of pain 
and decreased perspiration for these individuals results in a tendency to overheat.4, 5, 9, 16, 26  
Severe gastrointestinal (GI) disorders including diarrhea, gastroesophageal reflux disease (GERD), and 
constipation are commonly reported problems.3, 4, 16, 26, 32, 33 Cyclic vomiting occurs in up to 25% of 
individuals with PMS, which can lead to esophageal irritation, weight loss and dehydration.9 Feeding 
problems, choking and gagging, problems chewing, and pica are also common.2, 4, 26, 33 Incontinence 
affects a majority of individuals with PMS including daytime urinary incontinence (73%), fecal
incontinence (79%), and nocturnal urinary incontinence (86%).32, 33 Renal abnormalities are observed in 
up to 40% of patients.4, 16
Neurobehavioral characteristics include maladaptive behaviors and autism spectrum disorder or autistic 
behaviors.3-5, 9, 16, 19, 24 Up to 87% of PMS patients also meet diagnostic criteria for autism.7, 10, 16, 19, 34, 35
Externalizing behaviors such as biting, hair pulling and aggressive behavior are common.7, 10 Mood 
disruptions and maladaptive behaviors such as screaming and nonstop crying occur in up to half of 

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individuals with PMS.10 These individuals can also be at greater risk for the emergence of other 
psychiatric disorders such as anxiety, attention-deficit disorder, psychosis, bipolar disorder, and 
schizophrenia.5, 19, 21, 23, 24, 31, 36, 37   
5.2 
Current Treatments for Phelan-McDermid Syndrome 
There currently is no cure or treatment approved for PMS.  
Standard-of-care treatment for PMS takes a coordinated, multi-disciplinary approach targeted to the 
individual’s specific needs. The approach can require physical, occupational, behavioral, and speech 
therapies that include training on the use of alternative and augmentative communication (AAC) 
approaches such as picture boards or speech devices.2, 4, 9 The multi-disciplinary approach also includes 
orthopedic interventions, feeding therapy, and management of sleep problems.2, 9 Specialist care may be 
needed for the management of seizures, arachnoid cysts, GI issues, and renal dysfunction.4 Pediatric 
psychiatry specialists may also be involved for the management of behavioral, autistic, and psychiatric 
issues.4 GI symptoms such as constipation and vomiting are managed with standard treatments and 
approximately 50% of individuals are under the care of a GI specialist.33 Treatments such as anti-
convulsants for mood stabilization, neuroleptics and benzodiazepines are widely used in those with 
psychiatric co-morbidities or symptoms, often with concurrent treatment with multiple psychotropic 
medications including methylphenidate, alpha agonists, beta-blockers, SSRIs, valproic acid, lithium, 
atypical anti-psychotics and anti-depressants.24, 31, 36  
5.3 
Genetic Basis of Phelan-McDermid Syndrome 
Impairment in the structure and function of synapses is a fundamental underlying feature of PMS. 
Deletions and mutations of the SHANK3 gene lead to insufficient amounts of active SHANK3 protein, 
which is a key scaffolding protein present in the postsynaptic density of excitatory synapses. Normally, 
SHANK3 protein strengthens and stabilizes these synapses by providing a “docking station” for other 
proteins involved in synaptic structure and function.38  
5.4 
Cellular Pathology in Phelan-McDermid Syndrome 
The deficiency in active SHANK3 protein results in the biochemical, cellular, and morphological changes 
in the brain associated with PMS. Shcheglovitov et al.39 showed that in PMS, there are major impairments 
in excitatory synaptic transmission caused by defects in the structure of synapses. The level of Insulin-
Like Growth Factor 1 (IGF-1) in the brain is below normal in the Shank3 knockout model of PMS and in 
children with infantile autism in which SHANK3 mutations are prominent.40 IGF-1 exerts its effects on 
synaptic plasticity in part via the RAS-MAPK-ERK signaling pathway which plays an important role in 
regulating the cell cycle, gene expression, and protein synthesis41 and, as noted, is dysregulated in PMS. 
5.5 
Scientific Rationale for use of NNZ-2591 in Phelan-McDermid Syndrome 
NNZ-2591 (Cyclo-L-Glycyl-L-2-Allylproline) is a new chemical entity that is a synthetic analogue of 
cyclic Glycine-Proline (cGP), a metabolite of IGF-1 that is present naturally in the brain. 
cGP has been reported to regulate binding of IGF-1 to IGF Binding Protein 3 in the brain and, as a 
consequence, regulate the bioavailability of IGF-1 in the brain.42 This auto-regulatory mechanism 
maintains homeostasis of IGF-1, increasing bioavailability when IGF-1 is deficient and decreasing 
bioavailability when IGF-1 levels are excessive. In animal models of neurodevelopmental disorders 
including PMS, Fragile X syndrome and Prader-Willi syndrome, NNZ-2591 has restored IGF-1 to wild-

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neurological AEs. There were no clinically significant findings on the laboratory tests or 
electrocardiograms (ECGs), and no renal or hepatic findings were observed. 
 
PK appeared to be linear and predictable, with peak and total exposures (as measured by Cmax and area 
under the plasma concentration-time curve [AUC], respectively) appearing to increase in a generally 
dose-proportional manner after both the morning and evening doses.  
A summary of the study is provided in the NNZ-2591 Investigator’s Brochure.  
 
 

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Impact of Childhood Neurological Disability (ICND) Overall quality of life rating; caregiver-
assessed  
Exploratory Endpoints
Blood and stool samples will be collected for an exploratory analysis of biomarkers and gut microbiome. 
The analysis will be detailed in a separate analysis plan but will not include DNA sequencing. Samples 
will be collected at Screening (Visit 1) and Baseline (Visit 3, before dosing) and at the EOT visit (Week 
13, Visit 16), or upon early termination.

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STUDY DESIGN
7.1
Study Design Overview
This is a Phase 2, open-label study of the safety and tolerability of NNZ-2591 Oral Solution, 50mg/mL in 
male and female children and adolescents with PMS. Approximately 20 male and female subjects 
between the ages of 3 and 12 years will be enrolled and receive treatment of NNZ-2591 Oral Solution, 
50mg/mL for a total of 13 weeks. Additional subjects may be screened, enrolled, and treated to achieve 
approximately 20 study completers.
There will be a total of 17 study visits, comprising 5 in-clinic visits and 12 remote telemedicine/in-home 
nurse visits (see Section 7.1.1). The study will commence with an approximately 4 to 6 week Screening
and Baseline period. During this Screening/Baseline period, subjects will be assessed for study eligibility
and data will be collected to establish the subject’s baseline characteristics and symptom severity using a 
variety of assessments (Section 9.2). Two in-clinic visits and one remote/in-home visit (Visits 1, 2, 3)
comprise Screening and Baseline. 
Once eligibility is confirmed, subjects will receive the starting dose of 4 mg/kg and then be up-titrated to 
the target dose 12 mg/kg BID (see Section 7.2). Subjects will receive IMP for a total of 13 weeks. During 
the treatment period, there are three in-clinic visits: Week 2 (Visit 5), Week 6 (Visit 6) and Week 13 (Visit 
16). There is a combined remote, telemedicine visit by the site Investigator and an in-home visit by a visiting 
nurse for safety at Week 1 (Visit 4), Week 4 (Visit 7), Week 8 (Visit 11) and Week 10 (Visit 13). These 
combination remote/in-home visits will be conducted simultaneously whenever possible, or they will be 
conducted on the same day with the telemedicine visit occurring first. If it is not feasible to conduct these 
visits simultaneously or on the same day, the telemedicine portion of the visit and the nurse portion of the 
visit must be conducted on two consecutive days. In-home visits with a visiting nurse will be done at Weeks 
3 (Visit 6), 5 (Visit 8), 7 (Visit 10), 9 (Visit 12), 11 (Visit 14), and 12 (Visit 15).
All subjects will also have a remote follow-up visit with the Investigator via telemedicine and an in-person 
home visit by a visiting nurse approximately 2 weeks after the end of treatment (Week 15, Visit 17). 
For all visits designated as in-clinic, an in-person visit is preferred. Off-site assessments may be allowed 
due to extenuating circumstances due to the COVID-19 health emergency. All requests for off-site 
assessments must be approved in advance by the Sponsor or Medical Monitor.
Subjects will be divided into three groups by age: 
9 to 12 years old (Group 1)
6 to 8 years old (Group 2)
3 to 5 years old (Group 3)
Enrollment will commence with the oldest age group and will proceed as follows. After at least three 
subjects in Group 1 have received two weeks of treatment at the starting dose, the Data Safety Monitoring 
Committee (DSMC) will review data on safety and tolerability. If tolerability and safety for those subjects 
during the specified period is deemed acceptable, enrollment for Group 2 will proceed and dosing will 
begin at the starting dose. When at least three subjects in Group 2 have received the first two weeks of 
treatment at the starting dose, the DSMC will review data on safety and tolerability. If tolerability and 
safety for Group 2 is deemed acceptable, enrollment for Group 3 will commence and dosing will begin at 
the starting dose. 

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and they have not met any of the stopping criteria (Section 9.4.5), they can be down-titrated to the next 
lowest dose in the titration schedule. The Investigator must attempt to increase the dose as soon as it is 
possible based on the clinical situation. The aim is to return to the originally assigned dose. If the 
originally assigned dose cannot be reached or the subject is again unable to tolerate that dose, the 
Investigator will continue treatment on the highest dose that the subject can tolerate. 
 
 
Data from two weeks of dosing at each dose in the dose titration schedule will be reviewed by the DSMC 
before subjects are allowed to be administered the next highest dose. Subjects will stay on their current 
dose until the DSMC has reviewed the data and approved the subjects to escalate to the next dose.  
 
After eligibility is confirmed, the subject will be administered NNZ-2591 IMP open label at a starting 
dose of 4 mg/kg BID for a total of approximately 3 weeks. After 2 weeks of dosing at 4 mg/kg BID, the 
DSMC will review the safety data. The subject will remain on the starting dose during the DSMC review.  
If the DSMC determines that tolerability and safety during the 2-week dosing period are acceptable, the 
subject will escalate to the next dose of 8 mg/kg BID and be dosed for a total of approximately 3 
additional weeks at that dose. After 2 weeks of dosing at 8 mg/kg BID, the DSMC will review the safety 
data. If the DSMC determines that tolerability and safety during the 2-week dosing period on 8 mg/kg 
BID are acceptable, the subject will then escalate to the target dose of 12 mg/kg BID. After 2 weeks of 
dosing at 12 mg/kg BID, the DSMC will review the safety data to determine if the subject can continue 
dosing at 12 mg/kg BID for the remainder of the 13 weeks.  
 
The site will inform the caregiver of the up-titration decisions as soon as possible after the site has 
received the official notification of the DSMC decision. The site will verify with the caregiver that 
instructions to up-titrate to 8 mg/kg BID have been followed at the Week 4 visit (Visit 7), and will verify 
with the caregiver that instructions to up-titrate to 12 mg/kg BID have been followed at the Week 7 visit 
(Visit 10).  If the DSMC has not yet approved the subject to escalate to the next dose by the time of the 
relevant visit, the site should contact the caregiver within 24 hours of the receiving the decision from the 
DSMC. If the subject is not approved to titrate to the next dose, the site will contact the caregiver to 
discuss appropriate follow-up as is clinically indicated. At each visit, the clinician or nurse should check 
the dose when reviewing the caregiver diary.  
 
The DSMC will determine if dose escalation can proceed based on pre-specified stopping rules 
summarized for individual subjects in Section 9.4.5.  
 
Note that early cessation of IMP does not necessarily mean the subject is withdrawn from the study. With 
any early cessation of treatment, all evaluations and tests scheduled during the study must be conducted if 
possible. 
 
7.3 
Treatment Assignment 
This is an open-label study in which all subjects will be assigned to NNZ-2591 Oral Solution, 50mg/mL 
and receive 13 weeks of treatment. All subjects will be titrated to the dose of 12 mg/kg BID or the highest 
tolerated dose based on the Titration Schedule in Section 7.2. The dose titration schedule may be 
modified based on updated PK modelling including data from the study. 
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If a subject meets all eligibility criteria and written informed consent has been provided by a legally 
authorized representative, the subject will be enrolled into the study.   
7.4 
Study Timeline 
The study duration of 19 weeks from Screening to Follow-Up at Week 15 (+4 days).  
7.5 
COVID-19 
As a result of the COVID-19 public health emergency, this protocol includes provision for alternative 
methods of performing safety and efficacy assessments in accordance with the FDA Guidance on 
Conduct of Clinical Trials of Medical Products during the COVID-19 Public Health Emergency. ** 
Provision is made for off-site assessments where necessary and all efforts have been made to ensure the 
alternative processes are consistent as much as possible with in-clinic visits.  For visits that are designated 
as in-clinic, an actual in-clinic visit is preferred. However, an off-site visit may be conducted for a 
scheduled in-clinic visit in extenuating circumstances such as the COVID-19 health crisis with the prior 
approval of the Sponsor and Medical Monitor. Clinical investigators are to document the reason for any 
contingency measures implemented. If at any time in the study, the subject or his or her caregiver tests 
-CoV-2) or becomes ill with 
symptoms of Coronavirus disease (COVID-19), the family should be instructed to contact the site as soon 
as possible. Once informed, the Investigator should contact the Medical Monitor.  
 
 
 
 
 
** FDA Guidance on Conduct of Clinical Trials of Medical Products During the COVID-19 Public Health 
Emergency: Guidance for Industry, Investigators, and Institutional Review Boards (Center for Biologics 
Evaluation and Research; Center for Devices and Radiological Health; Center for Drug Evaluation and 
Research; Office of the Commissioner; Office of Clinical Policy and Programs; Office of Clinical Policy; Office 
of Good Clinical Practice) (2021). 

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SUBJECT POPULATION 
Approximately 20 male and female subjects between the ages of 3 and 12 years, inclusive, are planned to 
complete the study. 
The subjects will be categorized by age in three groups: 9 to 12-year-olds (Group 1), 6 to 8-year-olds 
(Group 2), and 3 to 5-year-olds (Group 3). Enrollment will be balanced to the extent possible by sex, and 
age with a minimum of 3 males and 3 females across all age groups, and a minimum of three subjects in
each age group.  
Enrollment will proceed by age group according to the following process: Enrollment will commence first 
in the oldest age group (Group 1). After at least three subjects in Group 1 have received two weeks of 
treatment at the starting dose, safety and tolerability data will be reviewed by the Data Safety Monitoring 
Committee (DSMC). If tolerability and safety for those subjects during that period is acceptable, 
enrollment for Group 2 will proceed and dosing will begin at the starting dose. When at least three 
subjects in Group 2 have received the first two weeks of treatment, safety and tolerability data will be 
reviewed by the DSMC. If tolerability and safety for Group 2 is deemed acceptable, enrollment for Group 
3 will commence and dosing will begin at the starting dose. Subjects in the younger age groups may be 
screened and enter the 4 to 6 week Screening period before DSMC review, but they will not be enrolled 
or dosed until the DSMC has reviewed and approved the initiation of dosing in that age group.
8.1
Inclusion Criteria
To be eligible for this study, subjects must meet all of the inclusion criteria and none of the exclusion 
criteria. Inclusion criteria includes:
1.
Clinical diagnosis of PMS with a documented disease-causing genetic abnormality of SHANK3  
2.
Males or females ages 3 to 12 years at Screening, inclusive
3.
Body weight of 12 kg or higher at Screening. Weight measurements may be repeated during the 
Screening period in consultation with the Medical Monitor.
4.
Subjects with a Clinical Global Impression – Severity (CGI-S) score of 3 or greater at the 
Screening visit
5.
Not currently actively undergoing regression or loss of skills defined as no persistent loss of 
previously acquired developmental skills for a period within 3 months of the start of Screening. 
a.
Previously acquired skills include any skill established and used on a daily basis for at 
least 3 months
b.
Variations in use of skills that is part of a general pattern of ups and downs, as 
determined by the Investigator, are not counted as regression.
c.
Skills may include language, non-verbal communication, fine motor skills, ambulation 
(including gait, coordination, independence of walking/standing), social skills, play, self-
help 
6.
Each subject must be able to swallow the IMP provided as a liquid solution
7.
The subject’s caregiver(s) must have sufficient English language skills to complete caregiver 
assessments in English.
8.2
Exclusion Criteria
To be eligible for this study, subjects must meet all of the inclusion criteria and none of the exclusion 
criteria. Exclusion criteria include:

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Laboratory and Screening Values 
1. 
Body weight < 12 kg at Screening. Weight may be repeated during the Screening period in 
consultation with the Medical Monitor. 
2. 
HbA1c values above 7% at the Screening visit. 
3. 
Clinically significant abnormalities (as determined by the Investigator) in safety laboratory 
values, vital signs, as measured at the Screening visit. Laboratory testing may be repeated 
during the Screening period in consultation with the Medical Monitor. 
4. 
Positive pregnancy test at the Screening visit. 
5. 
QTcF Exclusions (any of the following): 
a. Screening QTcF interval of > 450 ms assessed using Fridericia’s correction factor based 
on 12-lead ECG obtained as a continuous ECG of at least 50 seconds. 
b. Hypokalemia (Serum potassium at the Screening visit < 3.0 mmol/L or mEq/L). Serum 
potassium may be repeated during the Screening period with the agreement of the 
Medical Monitor. 
c. QTcF prolongation that is currently controlled with medication, in which normal QTcF 
intervals can only be achieved with medication. 
6. 
Any other clinically significant finding (as determined by the Investigator) on ECG at the 
Screening visit that would increase the likelihood of a severe arrhythmia. 
 
COVID-19  
7. 
Positive for SARS-CoV-2 at Screening or Baseline. 
8. 
Previous COVID-19 infection within the last 12 months that required admission to the hospital. 
9. 
Previous COVD-19 infection involving multi-organ systems, resulting in Multisystem 
Inflammatory Syndrome in Children (MIS-C) or with clinically significant sequelae. 
10. 
COVID-19 infection associated with acute kidney injury (AKI) or renal manifestations (e.g., 
proteinuria, hematuria, echogenic kidneys). 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 

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melatonin. Melatonin for difficulties with sleep onset is permissible and is not included in 
the count of psychotropic medications.   
b. The use of anti-epileptics for other indications such as the treatment of mood disorders 
counts towards the limit of permitted psychotropic medications.   
c. Anti-epileptic medications used for treatment of seizures does not count towards the limit 
of psychotropic medications.  
30. 
Current treatment with insulin or treatment within the last 12 weeks prior to commencement of 
IMP. 
31. 
Current treatment with IGF-1 or treatment within 6 months of commencement of the IMP. 
32. 
Current treatment with growth hormone or treatment within 12 months of commencement of the 
IMP. 
33. 
Non-pharmacologic somatic treatment (e.g., a ketogenic diet or vagal nerve stimulation) whose 
dosing regimen has not been stable at least 4 weeks prior to the start of Screening. If the 
treatment was discontinued, the discontinuation must have occurred no fewer than 2 weeks 
before the start of Screening.  
34. 
Patients planning to start a new behavioral, educational, or cognitive therapy during the period 
of the study or those who have begun a new behavioral or cognitive therapy regimen within 4 
weeks prior to the start of Screening.  
a. Note: changes to an ongoing treatment regimen that are due to school schedules or are 
otherwise seasonally related are not exclusionary as long as they are consistent with their 
typical type and pattern of behavioral treatment.  
35. 
Seizure medication whose dosing regimen is not stable 8 weeks prior to commencing IMP. 
Adjustments for changes in weight or age are allowable. If the treatment was discontinued, the 
discontinuation must have occurred no fewer than 2 weeks before the start of Screening. 
36. 
Psychotropic medications or any other medication used for a chronic illness (not including 
antibiotics, pain relievers, anti-diarrheals, and laxatives) whose doses and dosing regimen have 
not been stable for at least 4 weeks prior to the start of Screening. If the treatment was 
discontinued, the discontinuation must have occurred no fewer than 2 weeks prior to the start of 
Screening. 
a. This includes nutraceutical treatments and cannabinoids (tetrahydrocannabinol [THC] 
and cannabidiol [CBD]) which are allowable but also must meet the stability conditions 
above. 
b. Pain relievers, laxatives, and anti-diarrheals may be used as needed. 
c. Standard of care immunizations and vaccinations (including COVID-19) are allowed and 
are not subject to the above stability conditions. 
d. The Investigator should consult with the medical monitor if a subject is being treated with 
ocular toxic, hepatotoxic, nephrotoxic, or antibiotic medications.  
e. If the Investigator is unsure if a medication is permitted, the Medical Monitor should 
confirm if the medication is allowed and will provide written documentation to support 
the use of the medication, if allowed.  
 
Regression of Skills 
 
37. 
Actively undergoing regression or loss of skills defined as a persistent loss of previously 
acquired developmental skills within 3 months of the start of Screening.  
a. Previously acquired skills include any skill established and used on a daily basis for at 
least 3 months. 
b. Variations in use of skills that is part of a general pattern of ups and downs, as 
determined by the Investigator, are not counted as regression. 
c. Skills may include language, non-verbal communication, fine motor skills, ambulation 
(including gait, coordination, independence of walking/standing), social skills, play, self-

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help.  
 
Seizures 
 
38. 
Seizure profile that is not stable 8 weeks prior to commencing IMP. The overall pattern of 
seizure activity for the subject should be consistent with their typical pattern of seizures and be 
stable within the 8-week period in terms of type, intensity, duration, and frequency as 
determined by the clinical Investigator.  
 
Medical Conditions 
 
39. 
Currently pregnant, lactating, or breastfeeding. 
40. 
Current clinically significant (as determined by the Investigator) cardiovascular, 
gastrointestinal, respiratory, or endocrine disease, or clinically significant organ impairment.  
The Investigator may consult with the Medical Monitor as needed if he/she is uncertain if 
symptoms are exclusionary. 
41. 
Current clinically significant (as determined by the Investigator) hypo- or hyperthyroidism. If 
the subject has hypo- or hyperthyroidism that is controlled with medication, the Investigator 
should consult with the Medical Monitor to confirm if the subject is eligible.  
42. 
Type 1 or Type 2 diabetes mellitus requiring insulin (whether well controlled or uncontrolled), 
or uncontrolled Type 1 or Type 2 diabetes.  
43. 
Has planned surgery during the study. 
44. 
History of, or current, cerebrovascular disease or brain trauma. 
45. 
History of, or current catatonia or catatonia-like symptoms. 
46. 
History of, or current, malignancy. 
47. 
Current major or persistent depressive disorder (including bipolar depression). 
48. 
Significant uncorrected hearing impairment. 
 
Other Criteria 
49. 
Allergy to strawberry  
50. 
The subject is unable to take the IMP orally and swallow the IMP provided as a liquid solution. 
Administration of the IMP by nasogastric tube, feeding tube, thickened liquid, or gastrostomy 
tube is not allowed. 
51. 
Has participated in another interventional clinical study within 30 days prior to the start of 
Screening  
52. 
Prior enrollment in this clinical trial.  
a. Individuals who leave the study during the Screening period and have not entered the 
study may be able to rescreen pending review and approval of the Sponsor and Medical 
Monitor. 
b. Individuals who were deemed eligible and entered the study (enrolled) who discontinue 
the study may not re-enroll in the study.  
53. 
The subject is judged by the Investigator or the Medical Monitor to be inappropriate for the 
study for any reason. 
 
8.3 
Abnormal Laboratory Findings 
Where Screening safety laboratory tests (blood, urine) are found to be outside the reference range 
provided by the laboratory and the Investigator believes the results to be of clinical significance, the 
subject may be asked to return to the investigational site or have a nurse visit to allow for repeat sampling. 
If the abnormal finding has not reverted to normal or is regarded as being clinically significant, the 
subject will not be entered into the study but will be referred for further investigation, as appropriate. 

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Throughout the study, abnormal or out of range values should be reviewed by the Investigator who should 
make a determination if the values are clinically significant.  
8.4 
Withdrawal Criteria 
A subject’s legally authorized representative is free to withdraw consent and discontinue participation in 
the study at any time, without prejudice to further treatment, according to standard clinical practice. A 
subject’s participation in the study may also be discontinued at any time at the discretion of the 
Investigator. 
If the study treatment or observations are discontinued in any subject, the reason will be recorded on the 
e-CRF and the Sponsor notified promptly. 
8.5 
Risks and Benefits 
NNZ-2591 Oral Solution has been given to 28 healthy volunteers to date and was well tolerated. All 
reported adverse events were mild or moderate. There were no SAEs. There were no clinically significant 
findings from safety laboratory tests, vital signs, or cardiac tests. The most common TEAEs deemed 
related to drug were a cluster of apparently related neurological symptoms that included 
somnolence/drowsiness, blurred vision/difficulty focusing, ataxia/unsteady gait, dizziness, and vertigo. 
The majority of these TEAEs occurred within 2 to 3 hours of initial dosing. All resolved spontaneously 
without requiring medical intervention. There were no clinically significant findings on the laboratory 
tests or ECGs, and no renal or hepatic findings were observed.
 
 
 
 
Potential risks associated with the performance of the PMS assessments include fatigue, frustration, and 
provocation of maladaptive behaviors related to frustration in the children. Mild irritation or discomfort 
may be experienced from blood draws and ECG leads. 
 
Subjects may receive no direct benefit from participation in this study. However, participation will help 
the investigators better understand the safety of NNZ-2591 in people with PMS. Information obtained 
from this study may help people with PMS in the future, and may improve the way people with PMS are 
treated, as well as help them better manage their symptoms. Previous scientific information obtained from 
animal studies indicates that the signs and symptoms of PMS might be reduced following administration 
of NNZ-2591. It is possible that subjects will experience this same benefit following administration of the 
IMP.  
 
 

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STUDY PROCEDURES
9.1
Overview of Study Visits
There are a total of 17 study visits over the duration of the study: 5 in-clinic visits and 12 remote/in-home
visits (6 combined telemedicine/in-home nursing visits, and 6 in-home nurse visits; refer to the table of
assessments in Section 4). Remote visits between the Investigator or designee at the clinical site and the
subject at home are conducted via telemedicine or video facilities as appropriate. In-home visit refers to a
visit made to the subject’s home by a visiting nurse.
The Screening/Baseline period will be conducted over 4 to 6 weeks. The second visit during the 
Screening/Baseline period (Visit 2) should be conducted 2 weeks 
day after the Screening visit 
(Visit 1). The subject will then remain in Screening for an additional 2 to 4 weeks. The caregiver diary 
must be completed daily during the entire Screening/Baseline period whether it is 4 weeks or 6 weeks. 
The Screening visit (Visit 1) and Baseline visit (Visit 3) may be conducted over three consecutive days. It 
is preferrable that ECGs, safety labs and biomarker sample collection are conducted on the same day. No 
assessments can be conducted until informed consent has been given by the caregiver or legally 
authorized representative. Also, training for the caregivers on all caregiver completed assessments must 
be done before the caregiver rater may complete the assessments. All assessments must be done within 
the window for the visit, as shown in the Schedule of Assessments in Section 4. For Visit 3, all 
assessments must be done before administration of the IMP.
The in-clinic visits will be conducted in person at the study site. As described below, safety and efficacy 
assessments will be completed by site personnel. The caregiver will also complete caregiver assessments 
the day of the visit or the day before the visit as described below (except the caregiver diary which is 
completed daily), and these will be reviewed by site personnel. In-clinic visits will be done at Screening 
(Visit 1), Baseline (Visit 3), Week 2 (Visit 5), Week 6 (Visit 9), and Week 13 (EOT, Visit 16). For all 
visits designated as in-clinic (Visits 1, 3, 5, 9 and 16), an in-person visit is preferred. Off-site assessments 
may be allowed due to extenuating circumstances such as the COVID-19 health emergency. All requests 
for off-site assessments must be approved in advance by the Sponsor or Medical Monitor.
The combined remote telemedicine/in-home visits will be done during Screening/Baseline at Visit 2, and 
post-enrollment at Week 1 (Visit 4), Week 4 (Visit 7), Week 8 (Visit 11), Week 10 (Visit 13) and Week 
15 (Visit 17).  The combined remote visit is conducted by the site via telemedicine or video facilities, and 
by a visiting nurse who will conduct assessments at the subject’s home. These combination remote/in-
home visits will be conducted simultaneously whenever possible, or they will ideally be conducted on the 
same day. If not possible, the telemedicine visit and the nurse visit may be conducted on separate days. In 
this case, the telemedicine portion and in-home nurse portion must be conducted over two consecutive 
days.. During Screening (Visit 2), the Investigator will review the medical history to determine if there 
are any changes in symptoms from the Screening visit (Visit 1). At post-enrollment visits, the Investigator 
will do a review of AE/SAEs and tolerability and conduct a recent clinical history. A modified version of 
the physical and neurological exam will be done by the Investigator at the telemedicine visits based on the 
guidance document provided to the Investigator. At the in-home component of the visit during Screening 
(Visit 2), the nurse will collect vital signs, weight, do a Targeted Physical Exam assessing general
appearance, abdominal/CVA, and edema, and query oral intake. The nurse will review the caregiver diary 
during the visit and provide the family with a new section of the diary. Post-enrollment, for the in-home 
component of the combined visit, the nurse will collect urine, vital signs, weight, and blood samples for a 
comprehensive metabolic panel (CMP), complete blood count with differential (CBC) and coagulation, 
except for Week 1 when only the CMP sample is collected. The nurse will conduct a Targeted Physical 
Exam assessing: general appearance; the abdomen and the CVA region for tenderness; the extremities and 
peri-orbital region for edema.  A suprapubic exam (bladder palpation) to assess for urinary retention may 

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In-home Nurse Visit 
 
The in-home visit will be conducted by a visiting nurse who will also query any changes in tolerability 
during the in-home visit. Any changes will be noted and provided to the Investigator.  
 
The following assessments will be conducted and data collected by the home nurse during Follow-up: 
 
Review for AEs/ SAEs 
 
Review caregiver diary: concomitant medications, voids, oral intake, changes in symptoms 
 
Vital signs 
 
Weight 
 
Collect blood samples: 
o CBC with differential  
 
Coagulation 
 
CMP  
 
Collect urine for urinalysis 
 
12-lead ECG 
 
Targeted Physical Exam: general appearance, abdominal, CVA tenderness, check for edema. 
Exam may include a suprapubic exam (bladder palpation) to assess for urinary retention if 
decreased urine output is noted.  
 
9.3 
Screening and Baseline Procedures 
Screening and Baseline assessments are completed after informed consent during a period of 
approximately 4 to 6 weeks. During the Screening/Baseline period data will also be collected to establish 
the subject’s baseline characteristics and symptom severity based on assessments collected during the 
4 to 6 week period. There are two in-clinic visits and one remote/in-home visit for Screening and 
Baseline: Screening (Visit 1, in-clinic), Screening Visit 2, (combined remote/in-home nurse visit), 
Baseline (Visit 3, In-clinic). The second visit during the Screening period (Visit 2) should be conducted 
2 weeks ± 1 day after the Screening visit (Visit 1). The subject will then remain in Screening for an 
additional 2 to 4 weeks. The caregiver diary must be completed daily during the entire Screening period 
whether it is 4 weeks or 6 weeks.  
 
During the Screening visit (Visit 1), informed consent to participate in the study will be obtained from the 
parent or legally authorized representative.  
 
Subjects will be evaluated for the diagnosis of PMS and documented disease-causing genetic abnormality 
of SHANK3. If the subject has been genotyped at any time in the past, these will not need to be repeated at 
Screening, provided the documentation of these tests is available for verification.  
 
A rapid screening test for SARS-CoV-2 will be conducted by the site at Screening and Baseline. At 
Screening, a complete medical history will be conducted, and a neurological and physician exam will be 
done. 
 
 Caregivers will complete a 4 to 6 week diary to record seizure frequency, urine frequency 
(number of voids), any changes in symptoms or oral intake, and any changes in concomitant medications. 
 
Baseline cognitive characteristics will be assessed at the Screening visit using the Stanford-Binet 
Intelligence Scales version 5 (SB5) scored using the z-deviation method for intellectual disability or the 
Mullen Scales of Early Learning (Mullen) developmental quotients50. The Mullen will be done for 
subjects who cannot achieve basal on the SB5 or for whom the SB5 is developmentally inappropriate. 

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Each day there will be two dose administrations, one in the morning and one in the afternoon or evening. 
There should be at least 8 hours between doses. Doses should be given on an empty stomach (2 hours 
after the previous meal or snack and 30 minutes prior to the next). Doses may be taken over a 10-minute 
period with a follow up of 250 mL of water.  
For all subjects, the total duration of NNZ-2591 treatment will be 91 days. Dosing at the end Baseline 
counts as Day 1 whether one or two doses are given. Dosing may not exceed 91 days including Day 1, 
and all efficacy assessments for the EOT visit must be completed on or before Day 91 of treatment. 
The first dose of IMP will be administered in the clinic after all Baseline assessments are completed or, if 
the Investigator judges that it is too late in the day, on the following day. The subject should be monitored 
for at least three hours after the first dose. If the first dose is administered the day following Baseline, 
vital signs (except height) should be collected before the dose is administered. Day 1 of dosing is defined 
by the date when the first dose is taken. At this visit, the site will provide IMP for the caregiver to 
dispense at home. Enough IMP will be provided to cover the interval until the next in-clinic visit when 
the caregiver will be re-supplied from the site.  
Adjustment of Dose 
Within the up-titration period, if a subject is deemed not to be tolerating the current dose within the 
2-week period, and they have not met any of the stopping criteria below (see Section 9.4.5), they can be 
down-titrated to the next lower dose in the titration schedule (See Section 7.2). The Investigator must 
attempt to increase the dose as soon as it is possible based on the clinical situation. The aim is to return to 
the originally assigned dose. If the originally assigned dose cannot be reached, or the subject is again 
unable to tolerate that dose, the Investigator will continue treatment on the highest dose the subject can 
tolerate. Stopping rules for the discontinuation of the administration of IMP are described in Section  
9.4.5. Investigators are to discontinue administration of IMP if the subject meets any of the criteria 
described in Section  9.4.5. Note that early cessation of IMP does not necessarily mean the subject is 
withdrawn from the study. With any early cessation, all evaluations and tests scheduled during the study 
must be conducted if possible. 
 
The timing of administration of the IMP should be at approximately the same time each day. Each day 
there will be two dose administrations, one in morning and one in afternoon or evening. There should be 
at least 8 hours between doses. Doses should be taken by mouth either from a cup or via a dosing syringe 
provided by the pharmacist. Doses should be given on an empty stomach (2 hours after the previous meal 
or snack and 30 minutes prior to the next). The IMP should not be mixed with water, liquid thickeners, or 
food for administration. Doses may be taken over a 10-minute period with a follow up of 250 mL of 
water.  
The treatment times will be recorded in the Caregiver Diary and then entered into the eCRF. A Study 
Monitor will review subject source documents and IMP accountability records to assess treatment 
compliance on an ongoing basis during site visits. Subjects 
 
IMP, 
administered in accordance with the protocol are considered compliant. 
 
This study will be conducted as described in this protocol, except during an emergency situation in which 
the protection, safety and well-being of the subject requires immediate intervention, based on the 
judgment of the Investigator (or appropriately qualified designee). In the event of a significant deviation 

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Subjects who have received IMP for longer than 2 weeks and discontinue prematurely any time after Visit 
5 should return to the investigational site for final safety and efficacy assessments as scheduled for the 
EOT visit (Visit 16) and complete the study exit form. 
 
 
 

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mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), platelets (PLT), red cell 
distribution width (RDW-CV), and leukocyte count (neutrophils, lymphocytes, monocytes, 
eosinophils, and basophils). If abnormalities are seen, additional tests may be conducted as deemed 
necessary by the Investigator and Medical Monitor and as described below in the clinical management 
plan in Sections 9.5.2.1 and 9.5.2.3. 
 Coagulation (Visits 1, 3, 5, 7, 9, 11, 13, 16, 17): prothrombin time test; activated partial 
thromboplastin (aPTT), and International normalized ratio (INR). If abnormalities are seen, additional 
tests may be conducted as deemed necessary by the Investigator and Medical Monitor and as described 
below in the clinical management plan in Sections 9.5.2.1 and 9.5.2.3. 
 Comprehensive Metabolic Profile (All Visits except Visit 2): amylase, sodium, glucose, potassium, 
blood urea nitrogen (BUN), enzymatic creatinine, BUN/creatinine ratio, estimated glomerular 
filtration rate (eGFR), bicarbonate, chloride, total calcium, phosphorus, magnesium, bilirubin (direct 
and indirect), creatine kinase, alkaline phosphatase (ALP), aspartate transaminase (AST), alanine 
amino transferase (ALT), gamma-glutamyl transferase (GGT), total protein, albumin, total cholesterol, 
and random triglycerides. If abnormalities are seen, additional tests may be conducted as deemed 
necessary by the Investigator and Medical Monitor and as described below in the clinical management 
plan in Sections 9.5.2.1 and 9.5.2.3. 
o eGFR is calculated using the modified Bedside Schwartz formula: 
eGFR=(0.413*height)/creatinine mg/dL 
o This formula will be used for all subjects including those who may turn 18 years of age 
during the study. 
 Urinalysis (All visits except Visit 2): with microscopic analysis, glucose, bilirubin, ketones, specific 
gravity, blood, pH, protein, albumin, urobilinogen, nitrite, and leucocyte esterase. If abnormalities are 
seen on microscopy, additional tests for culture, sensitivity and protein analysis may be conducted as 
deemed necessary by the Investigator and/or Medical Monitor and as described below in the clinical 
management plan in Section 9.5.2.2.  
 
 Urine will also be tested at the Screening visit, for drugs of abuse, i.e., stimulants (e.g., amphetamine, 
methamphetamine, methylenedioxymethamphetamine [MDMA], cocaine), hallucinogens (e.g., 
phencyclidine), narcotics/analgesics/opiates (e.g., codeine, morphine, methadone, propoxyphene), 
depressants/sedatives/hypnotics (e.g., barbiturates). 
 TSH, Free T3, Free T4 (Visits 1, 16): free triiodothyronine (T3), free thyroxine (T4), thyroid 
stimulating hormone (TSH). 
 Glycosylated hemoglobin (HbA1c) (Visits 1, 16) 
 Rapid test for SARS-CoV-2 (Visits, 1, 3, 16). The site may use any test with same day results 
approved for use for children and adolescents in the US.  
 Serum Pregnancy Test (Visits 1, 9, 16): Females who have reached menarche will have a serum 
-HCG) at the Screening visit (Visit 1), Visit 9 (Week 6), and Visit 16 (Week 13, 
EOT).   
A central laboratory will be used for the safety sample analysis. Details on sample collection, handling 
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in the Laboratory Manual. Abnormal or out of range values should be reviewed by the Investigator who 
should make a determination if the values are clinically significant. The laboratory reference list 
designates normal ranges (for age and sex as applicable), and critical alerts for all blood and urine labs.  If 
abnormal results are observed in any of the above tests, additional tests may be conducted via the central 
laboratory or the site’s local laboratory as deemed appropriate by the Investigator and the Medical 
Monitor. 
It is preferable that repeat labs are done through the central laboratory. If not feasible, repeat labs may be 
collected at the site’s laboratory or a local laboratory. Repeat labs should be ordered stat. If repeat labs are 
not done through the central lab, a deidentified copy of the report must be provided in the subject’s study 
file. The reference values for the laboratory test for that lab must also be obtained and filed in the study 
files. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 

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as clinician’s summaries) should be available as source documentation of major medical conditions or 
events (e.g., surgeries) within the last two years. For subjects who are not a part of the clinical site’s 
practice, the study team should request families obtain summary medical records from their primary care 
provider (if available, or another qualified healthcare professional as determined by the Investigator) in 
preparation of the Screening visit. At each in-clinic and combined remote visit (Visits 4, 5, 7, 9, 11, 13, 
16 and 17), a current clinical history will be conducted by the Investigator or appropriately credentialed 
delegate. This will include review of any changes in urine voids or oral intake. 
 
A physical and neurological exam including a complete, standard review of systems will be undertaken 
by a physician (or appropriately credentialed delegate) at all in-clinic visits. The physical exam 
procedures will include the following organ systems: Head, ears, eyes, nose, and throat; Skin; 
Cardiovascular; Respiratory; Gastrointestinal; Genitourinary (as appropriate or indicated); 
Musculoskeletal; Allergies. The exam will include an assessment for signs of bladder or kidney pathology 
including an exam of the abdomen and both flanks, looking for signs of discomfort or distress. 
Assessment of edema will also be done. Exam may include a suprapubic exam (bladder palpation) to 
assess for urinary retention if decreased urine output is noted. 
A standard neurological exam will be undertaken at all in-clinic visits to include an evaluation of mental 
status, cranial nerves, motor exam, sensory exam, cerebellar (coordination, gait), reflexes.  
A modified version of the physical and neurological exam will be done by a physician (or appropriately 
credentialed delegate) via telemedicine at the remote visits (Visits 7 (Week 4), 11 (Week 8), 13 (Week 
10), and 17 (Week 15) based on guidance documents provided to the Investigator. The modified version 
of the neurological exam will follow recommendations for conducting telemedicine exams from the Child 
Neurology Society. Additionally, as part of the in-home visit, the nurse will conduct a targeted physical 
exam including assessment of general appearance, an abdominal and a costovertebral angle tenderness 
exam, assessment for signs of cystitis, and an assessment of edema. Exam may include suprapubic exam 
for bladder palpation if decreased urine output is noted. These are done at Visits 4 (Week 1), 6 (Week 3), 
7 (Week 4), 8 (Week 5), 10 (Week 7), 11 (Week 8), 12 (Week 9), 13 (Week 10), 14 (Week 11), 15 (Week 
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disorders, the CGI-S will be evaluated using PMS-specific scoring anchors. The clinicians will provide an 
overall global severity rating and a severity rating for each of seven domains: expressive communication, 
receptive communication, gross motor function, fine motor function, social interaction, self-care, and
cognition/learning. The clinician rater should assess the subject’s current state taking into consideration 
observations at the visit and symptoms within the last week. To ensure that interpretation of the scoring 
rubric is normalized among the raters, clinicians administering the CGI will be required to complete
scoring calibration training.
Clinical Global Impression of Improvement (CGI-I)
Clinical Global Impression of Improvement assessments will be made at Visit 9 (Week 6), EOT (Week 
13, Visit 16), and Follow-up (Visit 17). The CGI-I scale47 requires the Investigator to rate how much the 
subject’s illness has improved or worsened relative to a baseline state. A 7-point scale is used with the 
following values: 1, very much improved; 2, much improved; 3, minimally improved; 4, no change; 5, 
minimally worse; 6, much worse; 7, very much worse. The CGI-I will be evaluated using PMS-specific 
scoring anchors. The clinicians will provide an overall global improvement rating and an improvement 
rating for each of seven domains: expressive communication, receptive communication, gross motor
function, fine motor function, social interaction, self-care, and cognition/learning. The clinician should 
assess the subject’s current state taking into consideration observations at the visit and symptoms within 
the last week. The rating of change is compared with status at Baseline (Visit 3). To ensure that 
interpretation of the scoring rubric is normalized among the raters, clinicians administering the CGI will 
be required to complete scoring calibration training.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Mullen Scales of Early Learning or Stanford-Binet Intelligence Scales v5 (SB5) 
The Stanford-Binet Intelligence Scales version 5 (SB5) assessment will be made at the Screening visit
(Visit 1) and EOT (Week 13, Visit 16). SB5 is validated for ages 2 to 85+ and measures both verbal and 
nonverbal intellectual and cognitive abilities through a set of 10 subtests.49 General cognitive ability is 
reported as a full scale intellectual quotient score (FSIQ). Cognitive ability in five categories is reported 
in the index scores: fluid reasoning (FR), knowledge (KN), quantitative reasoning (QR), visual-spatial
processing (VS), and working memory (WM). Non-verbal (NVIQ) and verbal intelligence quotients 
(VIQ) are also calculated. Scoring of index scores and IQ will be calculated using the z-deviation method 
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The Mullen Scales of Early Learning (Mullen) is to be conducted in subjects who are unable to obtain a 
basal level on SB5 or for whom the SB-5 is developmentally inappropriate. Assessment will be made at 
the Screening visit (Visit 1) and End of Treatment (Week 13, Visit 16). The Mullen is designed for ages 0 
to 68 months but can be used with individuals older than 68 months who are developmentally delayed.51
The Mullen assesses developmental and cognitive functioning in five categories: gross motor (GM), 
visual reception (VR), fine motor (FM), expressive language (EL), and receptive language (RL). 
Standardized t-scores are calculated for the 5 scales, and an Early Learning Composite score reflecting 
cognitive development can be calculated from four cognitive Mullen scales (VR, FM, RL, and EL). The 
Early Learning Composite score and scaled scores are calculated for children 68 months and younger. 
Raw scores and age equivalents are calculated for all subjects.
If the SB-5 or the Mullen had previously been administered for the subject within 3 months of Screening, 
the scores from that administration may be used if it meets the following criteria: 1) Assessment was 
administered by site personnel, by another PMS NHS site, or another study site; 2) the site has access to 
all the scores required to be entered in the EDC; 3) the site has permission to share the scores from the 
previously administered assessment to the study EDC. Assessments done by the school or other clinics 
are not acceptable. Only scores from the SB-5 and the Mullen are acceptable; cognitive scores from other 
assessments cannot be entered in the EDC in lieu of the SB-5 or the Mullen. 
Both measures are used to assess cognitive and developmental status in the PMS Natural History study. 
MacArthur-Bates Communicative Development Inventory (MB-CDI)
The MacArthur-Bates Communicative Development Inventory (MB-CDI) will be completed at Baseline 
(Visit 3) and EOT (Week 13, Visit 16). This caregiver-completed instrument assesses language 
development in vocabulary comprehension and production, gestures, and grammar.52 Designed to assess 
early language development in infants and toddlers, it can also be used with older, developmentally
delayed children to assess developmental progress in language development. The MB-CDI includes three 
modules based on chronological or developmental age: Words and Gestures (8 to 18 months or 
developmental equivalent), Words and Sentences (16 to 30 months or developmental equivalent) and the 
CDI-III, an extension of the MB-CDI used with children 30 to 37 months (or developmental equivalent). 
The appropriate module will be used for this study in line with the cognitive and language development of 
the individual subject. The MB-CDI assesses developing abilities in language including production of 
gestures, and vocabulary comprehension and production which are reported as number of instances and 
percentile scores. 
ORCA (Observer-Reported Communication Ability Measure)
The Observer-Reported Communication Ability measure (ORCA) will be completed at Baseline (Visit 3) 
and EOT (Week 13, Visit 16). This caregiver-reported measure was originally developed and validated 
for Angelman syndrome53 to assess the individual’s overall communicative ability, and was designed to 
capture communicative abilities in verbal and low-verbal/non-verbal populations, so is relevant for PMS. 
It was developed based on feedback from a patient-focused listening session with the advocacy 
community and the Food and Drug Administration following best practices for measure development 
including concept elicitation interviews with caregivers and communication experts, item generation, 
assessment of validity and psychometrics, and factor analysis confirming single overall communication 
ability score.53-55 The rating scale evaluates the caregiver’s observation of the individual’s communication 
ability over the past 30 days.54 The measure consists of 84 total questions with 70 behavioral items.It 
assesses communication abilities of individuals across all modalities: gestures, AAC (augmentative and 
alternative communication) and speech so is not dependent solely on verbal abilities. Twenty-two 
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expressive communication, receptive communication, and pragmatic communication, rendering a total 
communication score. The ORCA is currently collected as part of the battery of the on-going PMS NHS. 
Caregiver Top 3 Concerns Rating
The Caregiver Top 3 Concerns Rating assessment is a syndrome-specific measure of 3 signs or symptoms 
of PMS identified by caregivers at Baseline as being priority concerns in which they would like to see 
improvement as a result of treatment. The assessment will be completed at all Screening and Baseline 
visits (Visits 1, 2, 3), as well as Week 6 (Visit 9), EOT (Week 13, Visit 16), and the Follow-up (Visit 17). 
In this assessment, concerns are identified on an individual, per-subject basis. The clinician should review 
the assessment with the caregiver at the Screening visit, ideally as part of the overall medical and clinical 
history. Caregivers should be encouraged, in selecting the concerns, to identify distinct, observable 
symptoms rather than broad ones. And caregivers should be advised to consider symptoms that they feel 
are important and have an impact on their child’s daily functioning and well-being. 
Caregivers are asked to identify 3 concerns from among 10 clinically important symptom domains: 
Communication, Social interaction, Gross motor skills, Fine motor skills, Behavior, Gastrointestinal 
problems, Seizures, Sleep, Sensory Sensitivity, and Self-care skills. Each individual concern identified 
should be from a different symptom domain, but caregivers can select any domain, and choose any 
symptom of concern within that domain. The same three concerns identified at Screening/Baseline are 
carried forward and rated at the follow-up visits. The severity of each concern is scored by caregivers 
using a 10-point Likert scale of severity. In rating, the caregiver should give consideration to symptoms 
within the last two weeks. 
 
 Aberrant Behavior Checklist-2 (ABC-2)
The ABC-2 will be completed at all Screening and Baseline visits (Visits 1, 2, 3), as well as Week 6 
(Visit 9), EOT (Week 13, Visit 16), and Follow-up (Visit 17). The Aberrant Behavior Checklist-2 (ABC-
2)56,57 is a caregiver-completed rating scale for assessing problem behaviors that has been validated in a 
variety of clinical populations and been used as an outcome measure in clinical trials of NDDs across 
much of the lifespan.56 The rater considers the relative frequency of an individual’s behaviors and gives a 
rating of the severity of the problem it presents: 0, not at all a problem; 1, the behavior is a problem but 
slight in degree; 2, the problem is moderately serious; 3, the problem is severe in degree. The caregiver 
should give consideration to symptoms within the last two weeks. 
The ABC-2 covers 58 symptoms providing five subscale scores: Irritability, Social Withdrawal, 
Stereotypic Behavior, Hyperactive/Noncompliance, and Inappropriate Speech. These subscales have been 
shown to have good consistency, reliability, and validity with normative data available for specific 
populations including children with intellectual disability and ASD.58 The ABC-2 is part of the 
assessment battery for the PMS-Natural history study. 
Behavior Problems Inventory-Short form (BPI-SF)
The Behavior Problems Inventory (BPI-SF) will be completed at Baseline (Visit 3) and at the EOT (Week 
13, Visit 16). The BPI-SF is a caregiver-completed rating scale for assessing self-injury, aggressive and 
stereotyped behavior.59 Frequency is assessed for all three types of behavior on a five-point scale: 0 
(Never), 1 (Monthly), 2 (Weekly), 3 (Daily), and 4 (Hourly). For self-injury and aggression, severity is 
also assessed on a 3-point scale of mild, moderate, or severe.

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Caregiver’s Impression of Change  
The Caregiver Impression of Change assessment will be done at the EOT visit (Week 13, Visit 16). The 
caregiver is asked to rate the change in his or her child’s overall function and well-being since the 
Baseline visit, and the change in specific symptoms. This is rated on a 7-point Likert scale: 1-Very much 
improved, 2-Much improved, 3-Improved, 4-Unchanged, 5-Worse, 6-Much worse, 7-Very much worse. 
For the rating of overall function, the caregiver also identifies the one symptom area or feature that has 
most influenced his or her rating of the child’s overall function and provides a description of symptom 
changes and impact of the changes. The assessment of change should be made since the Baseline visit
(Visit 3). The caregiver should assess the subject’s current state at the visit taking into consideration 
observations at the visit and symptoms within the last week. 
Quality of Life Inventory-Disability (QI-Disability) 
The Quality of Life Inventory-Disability (QI-Disability) will be completed at Baseline (Visit 3) and EOT
(Week 13, Visit 16).60-63 The QI-Disability60 is a caregiver-report measure that assesses a child’s well-
being and quality of life over the past month. Designed to be relevant for children who have an 
intellectual disability,60, 63 the QI-Disability includes 32 questions in 6 domains: Social Interaction, 
Physical Health, Independence, Positive Emotions, Leisure and the Outdoors, and Negative Emotions. 
The QI-D has been validated in individuals ages 5 to 18 with Rett syndrome, Downs syndrome, CDKL5
Deficiency Disorder, Cerebral Palsy, and ASD. Items are rated on a 5-point Likert scale with a 0-100 
scaling such that the value of each rating is: never = 0, rarely = 25, sometimes = 50, often = 75, and very 
often is 100. Domain scores are calculated by summing all the scores and dividing by the number of 
items. The total score is calculated by summing the domain scores and dividing by the number of 
domains. 
Impact of Childhood Neurological Disability-Overall Quality of Life Rating
(ICND)
The Impact of Childhood Neurologic Disability Scale (ICND) will be administered at Baseline (Visit 3)
and at EOT (Week 13, Visit 16). The ICND was developed to evaluate the impact that a child’s condition 
has on the child’s and the family’s everyday life.64 The full scale assesses the effect of four conditions or 
health problems on the child’s or the family’s life, and evaluates the child’s overall quality of life. In this 
study, only the overall quality of life assessment will be completed. The caregiver will rate overall quality 
of life of the subject by responding to the following: “Please rate your child’s overall ‘Quality of Life’ on 
the scale below. Choose the number which you feel is best and circle it”. The choices range from 1 
(“Poor”) to 6 (“Excellent”). The caregiver should consider the child’s status in the last month including 
their current condition. 
Child Sleep Habits Questionnaire (CSHQ)
The Child Sleep Habits Questionnaire (CSHQ) will be completed by the subject’s caregiver at all 
Screening and Baseline visits (Visits 1, 2, 3), as well as Week 6 (Visit 9), EOT (Week 13, Visit 16), and 
Follow-up (Visit 17). The CSHQ assesses sleep behavior, waking during the night, and morning 
waking/daytime sleepiness65 to assess both behavioral and medical sleep disorders. The CSHQ has been 
used across a range of NDDs including PMS and has been used as an outcome measure for sleep 
intervention trials.66-69 It provides a total score and eight subscale scores: bedtime resistance, sleep onset 
delay, sleep duration, sleep anxiety, night awakenings, parasomnias, sleep disordered breathing, and 
daytime sleepiness. The caregiver should consider sleep behaviors within the last week in doing their 
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9.6 
Pharmacokinetic Measurements 
Pharmacokinetic blood samples will be collected in accordance with the sampling schedule outlined  in  
Table 2 for ages 7 to 12 years old and Table 3 for ages 3 to < 7 years old. The date and actual time (hour 
and minute) that each sample is collected must be accurately recorded. The site must also ensure that the 
date and time of the previously evening’s dose and the morning and evening dose on the day the sample is 
collected is accurately collected in the Caregiver Diary.  
For the Week 2, 6, and 13 data collection, the previous day’s PM dose should be taken in the evening as 
late as possible, preferably before bedtime. The pre-dose sample should be taken 120 minutes to 15 
minutes before the morning dose is administered. For post-dose samples, sample collection can be +/- 15 
minutes of the target time and no closer than 30 minutes from the previous sample (must be at least 30 
minutes from the previous sample). The actual collection time is recorded. The post-dose windows are 
determined from the first dose of the visit (morning dose) and all PK samples should be collected before 
the second dose (PM dose). Full details regarding the PK sampling collection, storage and shipping may 
be found in the Laboratory Manual for the study. 
Pharmacokinetic blood samples may be collected from a cannula port or via venipuncture. Pre-prepared 
PK sampling tubes will be provided to each site within the lab visit kits for collection and storage of PK 
samples.  Samples of whole blood will be collected, aliquoted and will be stored at minus 20°C (or 
colder) no more than 2 hours following sample collection.  Samples will be shipped at designated times 
on dry ice and using temperature monitoring to the laboratory for storage and analysis. It is essential that 
accurate records are maintained regarding the date and time each PK sample is obtained, and the date and 
time each sample is placed in the 20°C freezer. The date and time of the most recent dose of IMP and 
most recent meal relative to that dose should be recorded in the Caregiver Diary.  
Minimum requirements for a subject to be considered evaluable within the PK population are 
administration of NNZ-2591 per protocol through to the morning dose at Week 2 (Visit 5) as a minimum, 
and collection of PK samples at the specified post-dose time point(s) through to Week 2 (Visit 5) as a 
minimum. 
 
 
 
 
 

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ADVERSE EVENTS
The Investigator and site staff are responsible for detection, recording and reporting of events that meet 
the criteria and definition of an adverse event (AE) or serious adverse event (SAE), as described below.
At in-home nurse visits, the nurse will do a query of any changes for potential AE/SAEs and document 
observations from the targeted physical exam. The nurse will escalate any issues related to AE/SAEs, 
stopping criteria, major dosing issues, or issues of potential safety concern to the Investigator the same 
day. Any changes noted will be provided to the Investigator who will be responsible for determining, 
recording, and reporting any events that qualify as AE/SAEs. 
10.1 Definition of Adverse Event
An adverse event is any untoward medical occurrence associated with the use of a drug in humans, 
whether or not considered drug related. An AE can be any unfavorable and unintended sign (e.g., an 
abnormal laboratory finding), symptom or disease temporally associated with the use of a drug, without 
any judgment about causality.  
AEs can include the following:
Exacerbation of a chronic or intermittent pre-existing condition including either an increase in 
frequency and/or intensity of the condition.
Conditions detected or diagnosed after IMP administration even though it may have been present 
prior to the start of the study.
Signs, symptoms, or the clinical sequelae of a suspected interaction.
Signs, symptoms, or the clinical sequelae of a suspected overdose of either IMP or a concurrent 
medication.
SAEs are a sub-category of AEs that are defined in Section 10.2, below. AEs/SAEs are recorded and 
reported from the time of first dose of IMP until Follow-up (Visit 17). 
Planned hospital admissions for an illness or a disease that existed prior to administration of IMP or 
enrollment at the clinical study are not to be considered AEs. Individuals who have planned surgical 
procedures that would occur during the study are to be excluded from the study (Exclusion 43).  If the 
subject has a planned hospital admission (non-surgical), the Investigator should consult with the Medical 
Monitor to ensure this will not cause disruption of IP administration or would not qualify the subject for 
exclusion. 
Note that medical or surgical procedures are not considered AEs (e.g., endoscopy); however the condition 
that leads to the procedure is an AE.
10.2 Definition of Serious Adverse Event
An adverse event or suspected adverse reaction is considered “serious” if, in the view of either the 
Investigator or Sponsor, it results in any of the following outcomes: death, a life-threatening adverse 
event, in-patient hospitalization or prolongation of existing hospitalization, a persistent or significant 
incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital 
anomaly/birth defect. Important medical events that may not result in death, be life-threatening, or require 
hospitalization may be considered serious when, based upon appropriate medical judgment, they may 
jeopardize the subject and may require medical or surgical intervention to prevent the outcomes listed in 
this definition.

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An adverse event or suspected adverse reaction is considered “life-threatening” if, in the view of either 
the Investigator or Sponsor, its occurrence places the subject at immediate risk of death. It does not 
include an adverse event or suspected adverse reaction that, had it occurred in a more severe form, might 
have caused death. 
 
 
 
 
 
 
 
 
 
 
 
10.4 Adverse Reactions 
An adverse reaction means any adverse event caused by drug. Adverse reactions are a subset of all 
suspected adverse reactions for which there is reason to conclude that the drug caused the event.  
Suspected adverse reactions means any adverse event for which there is a reasonable possibility that the 
drug caused the adverse event. For the purposes of IND safety reporting, ‘reasonable possibility’ means 
that there is evidence to suggest a causal relationship between the drug and the adverse event. 
10.5 Clinical Laboratory Abnormalities and Other Abnormal Assessments as AEs and 
SAEs 
Abnormal laboratory findings (e.g. CBC with differential, liver function, renal function, biochemistry, 
urinalysis) or other abnormal assessments (e.g. ECGs, vital signs) that are judged by the Investigator as 
clinically significant changes (new findings or worsening of baseline findings that are clinically 
impactful) will be recorded as AEs or SAEs if they meet the definition of an AE, as defined in Section 
10.1 (Definition of Adverse Event), or SAE, as defined in Section 10.2 (Definition of Serious Adverse 
Event).  Clinically significant abnormal laboratory findings or other abnormal assessments that are 
detected during the study and significantly worsen following the start of the study will be reported as AEs 
or SAEs. 
The Investigator will exercise his or her medical and scientific judgment in deciding whether an abnormal 
laboratory finding or other abnormal assessment is clinically significant. 
10.6 Time Period, Frequency, and Method of Detecting AEs and SAEs 
Any pre-existing conditions or signs and/or symptoms present in a subject prior to the start of the study 
(i.e., before on-study informed consent obtained) that do not result in the exclusion of the subject from 
participating in the study, should be recorded as Medical History. In addition, any medical occurrence 
which is reported after informed consent is obtained, but prior to the subject receiving IMP, should be 
documented as Medical History. If a baseline sign or symptom worsens following dosing, then this should 
be recorded as an AE or SAE as appropriate. 

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relationship of the event to the IMP will be considered and investigated. The Investigator will also consult 
the Investigator’s Brochure in the determination of his/her assessment.   
All AEs will be assessed by the Principal Investigator or qualified and authorized delegate as to whether 
there is a ‘reasonable possibility that the drug caused the event’ and on that basis be classified as either 
‘related’ or ‘not related’. 
There may be situations when an SAE has occurred and the Investigator has minimal information to 
include in the initial report to the Sponsor. However, it is very important that the Investigator always 
make an assessment of causality for every event prior to transmission of the SAE form to the Sponsor.  
The Investigator may change his/her opinion of causality in light of follow-up information, amending the 
SAE form accordingly.   
 
After the initial AE/SAE report, the Investigator is required to proactively follow each subject and 
provide further information to the Sponsor on the subject’s condition. 
All AEs and SAEs documented at a previous visit/contact and are designated as ongoing, will be 
reviewed at subsequent visits/contacts. 
All AEs will be followed until resolution, until the condition stabilizes, or until 30 days after the subject’s 
Follow Up visit (Visit 17). At which time, the appropriate AE/SAE eCRF page(s) will be updated. SAEs 
and g. renal AEs that are ongoing at the Follow-up visit (Visit 17) will be followed until resolution, 
stabilization of subject condition, or study end, whichever occurs first. In such cases, follow-up Serious 
Adverse Event Report (SAER) or Renal Adverse Event (RAER) forms will be completed at the Follow-
up visit (Visit 17) as well as completed upon resolution, stabilization, or study end, whichever occurs 
first. “Study end” is when all subjects have completed the study. 
The Investigator will ensure that follow-up includes any supplemental investigations as may be indicated 
to elucidate the nature and/or causality of the AE or SAE. This may include additional laboratory tests or 
investigations, histopathological examinations, or consultation with other health care professionals. 
The Sponsor may request that the Investigator perform or arrange for the conduct of supplemental 
measurements and/or evaluations to elucidate as fully as possible the nature and/or causality of the AE or 
SAE. The Investigator is obligated to assist. If a subject dies during participation in the study or during a 
recognized follow-up period, the Sponsor will be provided with a copy of the death certificate and any 
post-mortem findings, including histopathology. 
New or updated information will be recorded on the originally completed SAE or Renal Adverse Event 
form, with all changes signed and dated by the Investigator. The updated SAE form should be resent to 
the Sponsor within the time frames outlined below in Section 10.8 Prompt Reporting of the SAEs to the 
Sponsor.  
Any clinical adverse event that is serious (as defined above in Section 10.2) 
 
 occurring during the course 
of the study, irrespective of the treatment received by the subject, must be reported to the Sponsor and 
Sponsor’s agent within 24 h (or sooner if possible) of the Investigator or designee becoming aware of the 
situation. 

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10.9 Prompt Reporting of the SAEs to the Sponsor 
Once an Investigator or delegate becomes aware that an SAE has occurred in a study subject, she/he will 
report the information to the Sponsor’s appointed agent within 24 hrs. 
 
 will be the Medical Monitor for this study. 
  
 
 
  
 
             Email:
 
 
Serious Adverse Events will be processed by the Pharmacovigilance Team at
 with the 
support of and review by the Medical Monitor and Neuren’s Medical Team. A serious adverse event 
report (SAER) form is to be completed for each SAE occurring up to the final study visit, regardless of 
causality. This includes renal AEs that meet criteria for an SAE. In addition, the SAE is to be recorded on 
the appropriate section of the eCRF. The SAER must be submitted to the Pharmacovigilance Team at the 
email belowwithin 24 hours of the time the SAE is first observed.  
Submit SAER form via email within 24 hours of the event 
to:
 
 
The Medical Monitor or pharmacovigilance department will contact the Investigator should it be 
necessary to clarify any of the event information. The Investigator should provide follow-up information 
for the event to pharmacovigilance department as soon as it becomes available. If required, the 
Investigator should report these events to the local IRB. 
The SAE form will always be completed as thoroughly as possible with all available details of the event 
and signed by the Investigator (or authorized designee). If the Investigator does not have all information 
regarding an SAE, he/she will not wait to receive additional information before notifying the Medical 
Monitor of the event and completing the form. The form will be updated when additional information is 
received. 
The Investigator will always provide an assessment of causality at the time of the initial report as 
described in Section 10.7.2 Assessment of Causality. 
Any event that in the opinion of the Principal Investigator may be of immediate or potential concern for 
the subject’s health or well-being will be reported to the Pharmacovigilance Team, who will be in copy of  
Medical Monitor.  
In accordance with applicable regulations and local laws, the Sponsor will identify and report within the 
required time frame to regulatory authorities and Investigators all adverse events assessed as likely drug 
related that are determined to be both serious and unexpected. Investigators will be responsible for 
reporting this safety information to their IRB. 

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SAEs that are ongoing at the Follow-up visit (Visit 17) will be followed until resolution, stabilization of 
subject condition, or study end, whichever occurs first. In such cases, follow-up SAER forms will be 
completed at the Follow-up visit (Visit 17) as well as completed upon resolution, stabilization, or study 
end, whichever occurs first. “Study end” is when all subjects have completed the study. 
All SAE and AE data will be reviewed by the DSMC at scheduled meetings.  
10.10 Deaths 
A SAER form is to be competed for all deaths. Death will be recorded in the eCRF. Source 
documentation (e.g., autopsy report, death certificate) to confirm the cause of death will be reviewed by 
the DSMC.   
10.11 
 
 
 
 
 
  
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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10.12 Pregnancy 
Pregnant, lactating, or breastfeeding females are to be excluded from this study. In the event of 
pregnancy, it will be reported on a pregnancy form, and will be followed up to determine outcome, 
including spontaneous or voluntary termination, details of birth, and the presence or absence of any birth 
defects or congenital abnormalities. The investigator should report all pregnancies in female clinical trial 
subjects to the 
Pharmacovigilance Team as soon as possible using the Pregnancy Data Collection 
Form. 
Submit Pregnancy Data Collection form vial email to: 
 
 
It is not expected that there will be sexually active participants in the study population, and as such some 
of the provisions that follow may have limited applicability based on the age range of study participants 
and the nature of the disease under study. These provisions are nonetheless included for purposes of 
completeness.  
Subjects of childbearing potential must abstain from sexual activity for the duration of the study and for at 
least 30 days thereafter. If a subject is sexually active or becomes sexually active during the study, she or 
he must use 2 clinically acceptable methods of contraception (e.g., oral, intrauterine device [IUD], 
diaphragm plus spermicide, injectable, transdermal or implantable contraception, condom use alone (male 
type only)) for the duration of the study and for at least 30 days thereafter. 
 
 

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11.4 Efficacy Analysis
Efficacy will be assessed by looking at within-subject changes from the Baseline period to EOT using the 
efficacy endpoints listed in Section 6.3.2. 
The subject’s baseline characteristics and symptom severity will be established based on assessments 
collected during the 4 to 6 week Screening/Baseline period. Baseline values will be based on the average 
values of visits 1, 2, and 3 for assessments collected at more than one visit. A Wilcoxon signed rank test 
will be used to test for improvement and an exact significance level will be computed. 
Potentially influential factors will be considered and addressed with a linear regression model. This model 
may include covariates such as age, sex, nonverbal IQ (NVIQ) or NVIQ equivalent, genotype, history of 
regression (yes/no), ASD diagnosis (yes/no) with no more than two covariates included in any model. 
Descriptive statistics and corresponding graphics will be used to present the results. The safety and 
efficacy analysis details will be specified in the SAP.
11.5 Pharmacokinetic Analysis
The PK analysis will be based on the endpoints listed in Section 6.3.1. Pharmacokinetic (PK) measures 
will be collected from all subjects at Visits 5 (Week 2), 9 (Week 6,) and 16 (Week 13, EOT). 
NNZ-2591 PK concentrations will be listed by subject and time point for each dose level with actual time 
they were acquired. The concentrations will be summarized by time, dose level, and age group. For the 
concentrations measured at trough points dose relationship will be examined statistically with age group 
and/or body weight of subject as covariate.
Overall exposure parameters for NNZ-2591 such as Cmax and AUCtau may be derived by sparse non-
compartmental analysis (NCA). Additionally, PK concentrations of NNZ-2591 measured in pediatric 
subjects will be used to refine a population PK model developed from adult NNZ-2591 PK data and 
extrapolated to pediatric population. After refinement, complete profiles for each subject will be 
simulated using range of variability of model parameters and individual covariate effects. A standard 
NCA approach will be used for simulated profiles to calculate parameters Cmax, AUCtau, etc. for 
characterization of NNZ-2591 exposure in pediatric subjects. 
The PK analysis details will be specified in the PK SAP.
11.6 Biomarkers and Microbiome
Blood and stool samples will be collected for an exploratory analysis of biomarkers and gut microbiome. 
The analysis will be detailed in a separate analysis plan but will not include DNA sequencing. Samples 
will be collected at Screening (Visit 1) and Baseline (Visit 3, before dosing) and at the EOT visit (Week 
13, Visit 16), or upon early termination.
STUDY DRUG MANAGEMENT 
12.1 Identity of Investigational Medicinal Product
NNZ-2591 Oral Solution, 50 mg/mL is supplied in 250 mL white PET PP28 neck bottles with white 28 
mm child-resistant and tamper-evident caps. NNZ-2591 Oral Solution, 50 mg/mL IMP is manufactured 
under GMP by Quay Pharmaceuticals Ltd. (28 Parkway, Deeside Ind Park, Flintshire CH5 2NS).

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Study subjects will be instructed to return empty dosing bottles and any unused medication to the clinic. 
These returns will be accounted for in the clinic and the bottles and accountability form will be provided 
to the Pharmacy for reconciliation with dispensing and IMP tracking logs. 
At the end of the study, all unused IMP will be returned to the Sponsor’s designee or destroyed by the site 
according to the Sponsor’s instructions, once it has been inventoried and the Study Monitor has reviewed 
the IMP accountability records.  
12.3 Overdose 
Subjects should not exceed the maximum daily doses or take any two doses within an 8-hour interval. If 
an administered dose is spat out, regurgitated, or vomited, the dose should NOT be re-administered, and 
this should be documented in the dosing diary or the source documents for the in-clinic dose. There is no 
specific antidote to NNZ-2591 IMP. In the event of an overdose, appropriate supportive measures should 
be employed as clinically indicated and the Medical Monitor must be informed immediately. 

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QUALITY ASSURANCE AND DATA MANAGEMENT
13.1 Data Quality Assurance 
The following measures will be implemented to ensure accuracy, consistency, completeness, and 
reliability of data:
Investigator discussions
Site initiation training
Early site visits following enrollment
Routine site management
Ongoing site communication and training
Periodic site monitoring 
Data management quality control checks
Statistical quality control checks
Continuous data acquisition and cleaning
Internal review of data
Quality control check of the final study report
13.2 Case Report Forms
This study will utilize web-based eCRFs developed through a 21CFR Part 11 compliant platform. Prior to 
the initiation of the trial, each site will be contacted as to computer availability, hardware specifications, 
security infrastructure, internet connectivity, etc., to evaluate their capacity to use this type of data capture 
system. The Investigator and site personnel will be responsible for completing the eCRFs or ensuring the 
completion of forms to be completed by the caregivers and entered into the EDC via the secure portal for 
caregiver raters. The Investigator is responsible for the accuracy and reliability of all the information 
recorded on the eCRFs. All information requested on the eCRFs needs to be supplied, including subject 
identification data, visit date(s), assessment values, etc., and any omission or discrepancy will require 
explanation. All information on eCRFs must be traceable to source documentation at the site.
During periodic monitoring visits, the site will make their computer and/or high-speed Internet access 
available to the Study Monitor so that he or she may verify the data entries with the source 
documentation.  
13.3 Monitoring
A Sponsor’s Study Monitor will visit each site in accordance with the Clinical Monitoring Plan set forth 
for this trial as well as maintain regular telephone and written communication. Monitoring visits will be 
conducted by representatives of the Sponsor according to the ICH Guideline for Good Clinical Practice 
(GCP), and applicable regional regulations and guidelines.
The Investigator will agree to the monitors making periodic site visits during the study. The timing of 
these visits will be agreed by the monitors and the study site personnel. 

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Monitoring will be on an ongoing basis by site. The study assessments are to be captured on a specialized 
device/computer (e.g., 12-lead ECG), in an online or paper format (e.g., clinician and caregiver rating 
scales) and are to be obtained at the time of testing. It is imperative that the Investigator ensures that all 
tests are completed at each session, according to the subject’s capability. Data collected at the site will be 
entered into eCRFs in the centralized, password protected EDC system. Checking for completeness and 
rationality will be undertaken via the EDC at a central location. If discrepancies are noted, the site 
monitor will be alerted and site follow-up undertaken in order that problems may be resolved 
immediately. This may require retraining of investigators on the testing process and the importance of 
competing the testing correctly.  
13.4 Auditing 
The Sponsor (or Sponsor nominee) may conduct periodic audits of the study processes including, but not 
limited to, the clinical site and the bioanalytical laboratory. The Investigator must authorize access and 
make available all study related documents to authorized Sponsor’s representatives and regulatory 
authorities. 
The scope of a clinical site audit may include but will not be limited to, drug accountability, regulatory 
documentation, the informed consent process, and comparison of eCRFs against source data. The 
Investigator agrees to participate with audits conducted at a reasonable time and in a reasonable manner. 
Regulatory agencies involved with the study may also audit the Investigator during or after the study. The 
Investigator should contact the Sponsor immediately if this occurs. 
13.5 Source Documents 
The Investigator will, within reason, prepare and maintain adequate and accurate source documents (e.g., 
medical records, ECGs, raw data collection forms, and electronic source documents) to record all 
observations and other pertinent data for each subject enrolled into the study. The Investigator will allow 
Sponsor representatives and authorized regulatory authorities to access documents pertaining to the study. 
13.6 Protocol Deviations 
This study will be conducted as described in this protocol, except during an emergency situation in which 
the protection, safety and well-being of the subject requires immediate intervention, based on the 
judgment of the Investigator (or appropriately qualified designee). In the event of a significant deviation 
from the protocol, the Investigator or designee must contact the Sponsor or the Medical Monitor at the 
earliest possible time by telephone. This will allow an early joint decision regarding the subject’s 
continuation in the study. The Investigator will document the outcome of the discussion in the source 
documents and the Sponsor likewise will retain a documentary record of the decision. The Sponsor will 
reserve the right to recommend suspension or discontinued involvement of the site if excessive protocol 
deviations occur. 
13.7 Records Retention 
The Investigator must maintain essential study documents (protocol and amendments, completed eCRFs, 
source documentation, signed informed consent forms, relevant correspondence and approvals, and all 
other supporting documentation) until at least 2 years after the last approval of a marketing application in 
an ICH region and until there are no pending or contemplated marketing applications in an ICH region or 
at least 2 years have elapsed since the formal discontinuation of clinical development of the 
Investigational Medicinal Product. These documents should be retained for a longer period if required by 

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the applicable regulatory requirements or the clinical site’s procedures. Subject identification codes 
(subject names and corresponding study numbers) will be retained for this same time period and stored 
separately. Custody of the records may be transferred to another responsible party, acceptable to the 
Sponsor, which agrees to abide by the retention policies. Written notice of transfer must be submitted to 
the Sponsor. The Investigator must contact the Sponsors prior to disposing of any study records. 
Records retention will follow the Data Protection requirements in the participating country.

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ETHICS
14.1 Informed Consent
Written informed consent will be obtained from a parent or legally authorized representative of the
subject before any study-related procedures are performed. The Investigator has an ethical and legal 
responsibility to ensure the parent or legally authorized representative of each subject being considered 
for inclusion in the study is given a full explanation of the study. The Investigator or designee shall 
inform the parent or legally authorized representative of each subject in writing of all aspects pertaining to 
the subject’s participation in the study including (but not limited to) aims, methods, anticipated benefits, 
and potential risks. The subject’s parent or legally authorized representative will have the opportunity to 
inquire about details of the study and to decide whether to participate. 
A subject’s parent or legally authorized representative should understand that they are free to refuse to 
allow the subject to participate in, and are free to withdraw the subject from, the study at any time without 
prejudice or loss of medical care to which they are otherwise entitled. They have the ability to withdraw 
the subject from the study at any time, for any reason.
The parent or legally authorized representative of each subject must personally sign and date a study-
specific informed consent form on behalf of the subject for the subject to be a participant in the study. The 
subject’s caregiver who will complete the study assessments must also provide written informed consent 
regarding their participation in the study prior to participating in any study procedures. The form must be 
countersigned by the site Investigator who conducted the informed consent discussion (or an authorized 
designee). Authorized designees will be defined according to local center and ethics requirements. Their 
authorization will be documented on a written informed consent form, which, together with this protocol, 
will be approved by an IRB. 
A separate consent for potential re-use of leftover Biomarker and PK samples in later research, including
potential genetic research, is optional. 
Each informed consent will include the elements required by U.S. 21 CFR 50 and ICH E6, Section 4.8. 
The Investigator agrees to obtain approval from the IRB and Sponsor for any written informed consent 
form proposed for use in the study prior to submission to the IRB.
Each parent or legally authorized representative who provides written informed consent for a subject to 
participate in the study (by signing and dating of the form) will be given a copy of the signed informed 
consent form, and assent form if the minor is capable of signing an assent form or providing oral consent 
as required by local IRB regulations. The originals will be kept in the center’s regulatory file and a second 
copy filed in the subject’s medical record as permitted by the institution. The Investigator will inform 
subjects and the parent or legally authorized representative of new information that may be relevant to the 
subject’s willingness to continue participation in the study according to local ethics requirements.
It is important to obtain complete follow-up for all subjects enrolled. Every attempt should be made to 
undertake all protocol specified assessments and complete the eCRF except for those subjects who 
specifically withdraw consent for release of such information.
14.2 Institutional Review Board Approval
The Investigator will not begin the study until the protocol and informed consent form have been 
approved by the local Institutional Review Board (IRB) or specifically for the site by the central IRB as
dictated by institutional requirements. Any amendments to the protocol must also be approved in writing 

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by the Sponsor, and the local IRB or central IRB for the site prior to implementation by the Investigator, 
except where necessary to eliminate an immediate hazard to study participants. 
Written IRB approval of the protocol and Study Information Forms/Informed Consent Forms will be 
typed on the Institutional letterhead and will refer to the Study Information Forms/Informed Consent 
Forms and to the study by title and protocol number given by Neuren Pharmaceuticals on the protocol. A 
copy of the signed and dated letter of approval will be provided to Neuren Pharmaceuticals prior to study 
commencement. Any written information and/or advertisements to be used for volunteer recruitment will 
be approved by the IRB prior to use. 
All IRB correspondence including progress reports will be retained on file at the clinical site.  
14.3 Additional Protections for Minors 
The age-related inclusion criterion for the study protocol will allow enrollment of subjects aged 3 to 12 
years. Subjects aged younger than 18 are considered to be minors and, collectively, they constitute a 
vulnerable population. Additional regulations are in place for their protection (45 CFR Part 46 Subpart 
D).  Normally, minors cannot legally provide consent to participate in research on their own behalf.  
Consent must be provided by one or both parents, or a legally authorized representative, while the minor 
may provide “assent” for participation per local IRB requirements. Assent is the minor’s affirmative 
agreement to participate in the research.   
Since this protocol involves greater than minimal risk but presents the prospect of direct benefit to all 
subjects enrolled, consent shall be obtained from a guardian or at least one parent in accordance with local 
IRB requirements. Minors will be given the opportunity to assent to participation if and when they are 
considered capable of doing so by the Investigator and per local IRB requirements. 
 
 

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STUDY MANAGEMENT
The Sponsor will appoint the project management team, and an independent DSMC. Project management 
may be delegated to a Contract Research Organization who will be overseen by the Sponsor.
15.1 Principal Investigators
A Principal Investigator will be appointed at each participating site to personally supervise all aspects of 
the conduct of the study at their site. 
15.2 Data Safety Monitoring Committee
An independent DSMC will monitor the progress of the trial and ensure that the safety of trial subjects is 
not compromised. The DSMC will provide independent affirmation that no safety or tolerability issues 
are arising in the study through their on-going review of the study data. Specifically, the DSMC will 
review the clinical safety data prior to any individual dose titration and prior to initiation of subsequent 
age groups. The DSMC will review safety data and make an adjudication on: 1) the ability for any 
individual subject to escalate to the next higher dose and 2) the ability for enrollment to begin in the 
younger age groups (Groups 2 and 3).
The DSMC will consist minimally of a clinical chair, another physician experienced in clinical trials with 
pediatric expertise (but not participating in this study), and a pediatric cardiologist. The DSMC Charter 
details the DSMC processes, duties, and responsibilities as well as the study-wide stopping criteria.
15.3 Publications
All publication rights are delineated in the Clinical Study Agreement and/or other separate agreements 
with the Investigator and/or Institution, as applicable. International Committee of Medical Journal Editors 
(ICMJE) uniform requirements will be respected, with regard to the composition, authorship and 
submission of manuscripts derived from this study. A publication committee will be composed that will 
include the principal investigators (or appropriate designees) as well as Sponsor representatives.  

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Allometric scaling to determine phase 2 exposures
To determine the appropriate dose for pediatric patients, the Sponsor performed allometric scaling as 
discussed with the FDA in the Pre-IND Meeting. The findings from the allometric scaling analysis are 
summarized below. 
The allometric scaling analysis was performed using the pharmacokinetic data from the Phase 1 study of 
NNZ-2591 in healthy adults (PK Report Neu-2591-HV-001). The purpose of the allometric scaling is to 
predict exposure in younger and lighter patients based on observed exposures in adult healthy volunteers 
at steady-state from the completed clinical study (Neu-2591-HV-001) for the dose of 12 mg/kg (cohort
M2). 
1. Methods for the Allometric Scaling
Steady-state PK parameters were used in the modeling. Median and percentiles were estimated for steady-
state clearance CLss/F on Day 7 morning dose for the adult subjects in the Neu-2591-HV-001 study to be 
used as input for allometric scaling. Median and 5th and 95th percentiles for the AUCtau at steady-state for 
the adult subjects were used as a target exposure in children for comparison of the results. 
Fi value was already accounted for in the apparent steady state clearance CLss/F. The WTcentered value for 
the study was median body weight for the subjects in M1 and M2 cohorts of the study Neu-2591-HV-001 
was equal to 73 kg. 
Median CLss/F derived for steady-state exposure for Day 7 morning dose was used as CLTV. Since the 
CLss/F was derived for body weight adjusted doses and hence was estimated as L/h/kg for the 
simulations, the value was multiplied by the median weight of 73 kg to represent true value for the 
population of adult subjects in the study Neu-2591-HV-001. 
For simulation of exposure for children 3-17 (covering the planned age group for this Phase 2 study and 
studies in PTHS and AS with children up to 17 years old), the Centers for Disease Control and Prevention 
(CDC) Growth Individual charts with 3rd and 97th percentiles (3rd, 10th, 25th, 50th, 75th, 90th, and 
97th) were downloaded from the CDC.gov website. The body weights for boys and girls from 36.5 
months (3 years) to 17 years old (203.5 months) inclusive were combined for the input to Phoenix 
WinNonLin as a csv file. The file contained columns for 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 
97th percentiles for each month of age and gender individually. Column with gender was added for the 
combined dataset. Age groupings for the allometric scaling analysis were Group 1 (3 to < 6), Group 2 (6 
to <12), and 12-17.
The equation for allometric scaling was implemented in the Data Wizard function of Phoenix WinNonLin 
using weight for children of different age, gender, and percentile as direct input. 
Doses were varied in the range from 11 to 20 mg/kg for final estimate with 1 mg/kg increments. The dose 
levels 11, 12, 13, 14, … 20 mg/kg were used to calculate the related exposures for different body weight 
values and compare the resulting AUCtau values with adult results. 
Additionally, a 17.5-mg/kg dose was evaluated for the lowest body weights. Preliminary evaluation of 
suitable doses was done starting from 3 mg/kg dose levels. The parameters derived for this allometric 
scaling were AUCtau at steady state to compare with adult exposures.

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2. Allometric Scaling Results
Non-compartmental parameters for NNZ-2591 in adult subjects from the study Neu-2591-HV-001 were 
evaluated for dose proportionality of exposure after single, first doses and multiple steady-state doses of 
NNZ-2591 in healthy adult subjects. Evaluation of dose proportionality supported the application of the 
published allometric scaling formula to steady state exposure parameter AUCtau to be matched to adult 
exposures using body weight normalized dose in mg/kg and apparent steady state clearance in healthy 
adult subjects. The predicted exposures (steady-state AUCtau) were calculated from adult median CLss/F, 
estimated for morning and evening 12 mg/kg doses on Day 7 in the study Neu-2591-HV-001, for 
different dose values and body weights from CDC Growth Chart. 
The findings showed that overall, the predicted pediatric exposures were lower than adult exposures for 
the 12mg/kg dose for comparisons of exposure for different dose values versus weight. Combining the 
dose into 3 age groups resulted in significant overlap of body weight and differences in the dose projected 
to match adult exposure for 12 mg/kg dose within the group. Hence, body weight-based dosing instead of 
age-related dosing was originally proposed for the dose selection for children. The combined plots of 
AUCtau vs weight are shown in Figure A 1. 
Figure A 1 Predicted AUCtau of NNZ-2591 for different dose values vs weight all ages combined

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Solid lines – mean AUCtau, dash-dot lines – 90% CI. Blue – male, pink – female 
AUCtau_sim – simulated AUCtau at steady state for 12 mg/kg BID dosing, h*ng/mL 
a Source: Neu-2591-HV-001 study adpc dataset, Phoenix 8.3 output for Project file Allometric 
Neuren.phxproj; CDC Growth chart reported in Figure 5 in the Allometric Scaling Report. 
b Report 1901515 and Report SOW6, 0621-20173NB_w_in-life_Bioanalytical and Pharmacokinetic 
Report_Mouse Whole Blood_NNZ-2591_27Aug2020 
This more conservative approach, which maintains the planned staggered enrollment of age groups, 
ensures that each nominal dose is administered to the older group before that dose is administered in the 
younger pediatric patients. As such the younger age groups receive only nominal doses that have been 
administered to the older group instead of exposure-equivalent weight-based doses at higher nominal 
doses. Given that it was estimated from allometric scaling that exposures would be lower for children < 
70 kg at 12 mg/kg than for adults at 12 mg/kg, dosing all children at a maximum of 12 mg/kg will not put 
them at risk of exposures higher than that experienced by healthy adults. So, this approach to the dosing 
maintains the balance between risk and benefit for this first Phase 2 study in the Phelan McDermid 
syndrome population.  
 
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