The Safety and Tolerability of COMP360 in Participants With Post-traumatic Stress Disorder
Phase: PHASE2
Conditions: Post Traumatic Stress Disorder
Sponsor: COMPASS Pathways

Version 4.0 (USA) – 18 August 2022
DRUG:
COMP360
STUDY NUMBER:
COMP 201
PROTOCOL TITLE:
The Safety and Tolerability of COMP360 in Participants 
with Post-traumatic Stress Disorder 
CLINICAL PHASE
II
ClinicalTrials.gov IDENTIFIER:
NCT05312151
EudraCT NUMBER:
2021-002621-19
SPONSOR:
COMPASS Pathfinder Limited 
VERSION NUMBER:
V 4.0 (USA)
VERSION DATE:
18 August 2022
CONFIDENTIALITY STATEMENT
The information provided in this document is strictly confidential and is available for 
review to Investigators, potential Investigators, appropriate ethics committees and other 
national authorities. No disclosure should take place without the written authorisation from 
the sponsor, except to the extent necessary to obtain informed consent from potential 
participants.

Protocol number: COMP 201 
COMPASS Pathfinder 
Limited 
The Safety and Tolerability of COMP360 in Participants with 
Post-traumatic Stress Disorder 
Confidential 
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STUDY NUMBER: COMP 201  
THE SAFETY AND TOLERABILITY OF COMP360 IN 
PARTICIPANTS WITH POST-TRAUMATIC STRESS DISORDER  
CONFIDENTIALITY AND INVESTIGATOR STATEMENT 
The information contained in this protocol and all other information relevant to COMP360 
are the confidential and proprietary information of COMPASS Pathfinder Limited 
(COMPASS), and except as may be required by federal, state or local laws or regulation, 
may not be disclosed to others without prior written permission of COMPASS.  
I have read the protocol, including all appendices, and I agree that it contains all the 
necessary information for me and my staff to conduct this study as described. I will conduct 
this study as outlined herein, in accordance with the regulations stated in the Code of 
Federal Regulations (CFR) for Good Clinical Practices (GCP) and International Council 
for Harmonisation (ICH) guidelines and will make a reasonable effort to complete the study 
within the time designated.  
I will provide all study personnel under my supervision copies of the protocol and any 
amendments, and access to all information provided by COMPASS or specified designees. 
I will discuss the material with them to ensure that they are fully informed about COMP360 
and the study.  
 
 
 
Principal Investigator Name (printed) 
 
Signature 
 
 
 
Date 
 
Site Number 
 
 
 

Protocol number: COMP 201 
COMPASS Pathfinder 
Limited 
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Post-traumatic Stress Disorder 
Confidential 
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PROTOCOL SYNOPSIS 
Protocol number 
COMP 201  
Protocol Title:  
The Safety and Tolerability of COMP360 in Participants with Post-
traumatic Stress Disorder 
EudraCT Number: 
2021-002621-19 
Investigational Medicinal 
Product: 
COMP360 
ClinicalTrials.gov 
Identifier: 
NCT05312151 
 
Clinical Phase: 
II 
Rationale: 
The Post-traumatic Stress Disorder (PTSD) Psychopharmacology 
Working Group has recently called for novel, effective and efficient 
trauma-focused interventions and has labelled current treatment outcomes 
as “the Crisis in the Pharmacotherapy of Post-traumatic Stress Disorder”.1  
MDMA-assisted psychotherapy has recently received Breakthrough 
Therapy designation (BTD) by the FDA for PTSD, implying that 
psychedelic-assisted psychotherapies may provide better outcomes for 
patients than the current standard of care. Psilocybin therapy with 
COMP360 (COMPASS Pathways’ proprietary synthetic psilocybin 
formulation) has received similar BTD for treatment-resistant depression, 
a condition often comorbid with PTSD.  It is therefore reasonable to 
obtain proof of feasibility for COMP360 therapy for PTSD.  If 
demonstrated safe and well tolerated, COMP360 therapy may offer a 
powerful alternative to MDMA-assisted psychotherapy in reducing PTSD 
symptoms. 
Target Population: 
PTSD 
Number of Participants: 
Up to 20 participants  
Objectives:  
Primary Objective 
x 
To assess the safety and tolerability of COMP360 administered under 
supportive conditions in PTSD participants 
Secondary Objectives 
x 
To assess the efficacy of COMP360 administered under supportive 
conditions in reducing PTSD symptoms 
x 
To assess the effects of COMP360 administered under supportive 
conditions on quality of life and participant functional impairment 
Exploratory Objectives 
x 
To assess participants subjective experience of COMP360 
administered under supportive conditions 

Protocol number: COMP 201 
COMPASS Pathfinder 
Limited 
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Post-traumatic Stress Disorder 
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x 
To assess participants perceived growth and resilience after 
COMP360 therapy 
x 
To evaluate the impact of COMP360 on real life functional activity 
estimated from passive data streams collected on the Measure 
Health app on participants' mobile phones  
x 
Natural language processing on the participant narrative during the 
interactions with the therapist 
x 
To assess the influence of COMP360 therapy on blood biomarkers  
x 
To assess the influence of COMP360 therapy on brain activity   
Study Design and 
Procedures: 
This is a phase II, multicentre, fixed-dose open label trial. The study 
population will include adult men and women outpatients, 18 years of age 
and older meeting Diagnostic and Statistical Manual of Mental Disorders 
(5th Edition; DSM-5) diagnostic criteria for PTSD after a traumatic event 
experienced during in adulthood.  
After signing the informed consent form (ICF), participants will be 
assessed for their eligibility with the Mini International Neuropsychiatric 
Interview, version 7.0.2 (MINI 7.0.2), the PTSD Checklist for DSM-5 
(PCL-5), Life Events Checklists for DSM-5 (LEC-5), the Childhood 
Trauma Questionnaire (CTQ) and the Columbia- Suicide Severity Rating 
Scale (C-SSRS). Those who meet the eligibility criteria will enter the 
screening period. Additionally, a medical history, an electrocardiogram 
(ECG), blood tests, and vital signs will be obtained. Participants will be 
offered the option of enrolling in the neuroimaging component of the 
study. Participation in this part of the study is optional, and participants 
who do not consent to neuroimaging will not be excluded from the study.  
If participants consent to neuroimaging, they will be assessed for 
additional eligibility criteria for the Magnetic Resonance Imaging (MRI) 
scan.  
During the screening period, participants who are on antidepressant 
and/or antipsychotic medications will be expected to complete tapering of 
these medications at least 2 weeks prior to baseline. Participants will be 
given a choice of the tapering rate. During the tapering period all 
participants will be supported by the study clinician.  
Once the participant has been evaluated as eligible, they are invited to 
enter the screening period visits. During the first of these visits the 
participant begins tapering off their antidepressant and/or antipsychotic 
medications, if appropriate. The participant must complete the taper 
within the first 4 weeks of this period, prior to 2 weeks completely off 
antidepressant and/or antipsychotic medications, before the baseline visit. 
The designated study team member will be in frequent contact with the 
participants to monitor for withdrawal and worsening of symptoms. The 
participant will meet with a therapist for a minimum of 3 visits during 
screening. These are safety sessions and will contribute to the 
participant’s preparation for the COMP360 administration session. 
All participants will be evaluated for safety at the clinic weekly for a 
minimum of three weeks prior to COMP360 administration to ensure safe 
discontinuation of current antidepressant therapy required by the protocol. 

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Post-traumatic Stress Disorder 
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Participants’ companions (carers, friends, or family members) may be 
educated about the signs of worsening of PTSD and suicidality and 
instructed on ways to contact the study team in case of significant 
worsening. During these visits the C-SSRS, the Modified Discontinuation 
Emergent Signs and Symptoms Scale (mDESS), and any changes in 
medications since the previous visit will be obtained in addition to other 
assessments at the study clinician’s discretion. The designated study team 
member will contact the participant by phone calls in between in clinic 
visits during screening period to monitor for withdrawal and worsening 
of symptoms. 
The day before the administration session, the participants will undergo a 
baseline assessment (3 to 6 weeks after beginning screening period) that 
will consist of the Clinician-Administered PTSD Scale for DSM-5 
(CAPS-5), Sheehan Disability Scale (SDS), EuroQuol-5 Dimensions- 5 
Levels (EQ-5D-5L), C-SSRS, Brief Psychiatric Rating Scale – Positive 
symptom subscale (BPRS+), Perceived Ability to Cope with Trauma 
(PACT), Resilience Adult Scale (RAS), a semi-structured interview on 
the management of their PTSD, vital signs, urinalysis, urine drug screen, 
and urine pregnancy test (only for women of childbearing potential). After 
baseline data are collected and entered in the Electronic Data Capture 
(EDC), the Clinical Assessment Technologies Team (CAT) team will 
complete a final review to ensure the participant’s continued eligibility. 
Participants cannot be progressed to the administration session until this 
approval is received. Full descriptions of the activities carried out during 
the therapist sessions can be found in the Therapist Manual. Those who 
agreed to take part to the optional neuroimaging component of the study 
and met the eligibility criteria will be offered an MRI scan. To reduce 
participant burden on baseline visit, the MRI scan can be organised within 
7 days prior to the baseline visit. The investigator will be responsible of 
confirming eligibility of the participant before MRI.  
The following day, the participants will attend the clinic for the dosing 
session that will last approximately 6-8 hours and will be supported by 
two designated trained therapists. Participants will receive 25 mg 
COMP360. A full description of the activities of the administration 
session is found in the Therapist Manual. After the acute effects of 
COMP360 pass, participants will complete the Five-Dimensional Altered 
States of Consciousness (5D-ASC), and will be evaluated for safety and 
accompanied home. On the following day, participants will be seen in 
person for a safety check, assessment of suicidality, and to discuss their 
experience during the dosing session (integration). During this visit, 
participants will complete a semi-structured interview on the acceptability 
of the therapeutic intervention and the severity of PTSD symptoms will 
be evaluated using the PCL-5. All sessions between the therapists and the 
participant may be audio recorded for adherence monitoring and quality 
assurance. Audio and video recording of the sessions are subject to 
participant consent. Participants who do not consent to either or all 
recordings will not be excluded from the study.  
All participants will be asked to remain off medications for their PTSD 
symptoms for at least 4 weeks following the administration session. 
Rescue medications are allowed as noted in the protocol. Participants who 
restart their medications during the first 4 weeks after the dosing session 

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Post-traumatic Stress Disorder 
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will be assessed for reasons of resuming their medications and followed 
until 12 weeks post COMP360 administration. Participants will be seen 
at the clinic for screening (plus a minimum of 3 safety visits), baseline, 
day 1, day 2, week 1, week 2, week 4, and week 12 visits. Participants 
will also be contacted for a remote follow-up at week 6 and week 9. The 
option of an in clinic visit at weeks 6 and 9 will also be available. See 
Section 5.3 for a full schedule of assessments. Participants who agreed to 
the optional neuroimaging component of the study will be offered an MRI 
scan at week 4.  
 
Eligibility Criteria: 
Inclusion Criteria 
To be eligible for the study, participants must meet the following criteria: 
1. Signed ICF 
2. 18 years of age or older at screening 
3. Meet DSM-5 criteria for current PTSD resulting from a trauma 
experienced during adulthood measured via the PCL-5 in 
combination with the LEC-5 at screening  
4. Meet DSM-5 criteria for current PTSD resulting from a trauma 
experienced during adulthood as assessed by the CAPS, with a 
minimum score of 25 at baseline 
5. Able to identify a next of kin who is willing and able to be 
reached by the investigators in case of emergency  
6. Have successfully discontinued all prohibited medications at 
least two weeks prior to baseline visit. For fluoxetine (Prozac), 
immediate cessation at screening period visit 1a followed by at 
least four weeks of run-in will be required prior to baseline 
7. Able to complete all protocol required assessment tools without 
any assistance or alteration to the copyrighted assessments, and 
to comply with all study visits 
Inclusion Criteria for subset of participants agreeing to the optional 
MRI scan: 
1. Have consented to take part in the neuroimaging component of 
the study 
 
Exclusion Criteria 
Exclusion of potentially confounding psychiatric diseases and therapies: 
1. Current or past history of schizophrenia, schizoaffective disorder 
or any other form of psychotic disorder, obsessive compulsive 
disorder, personality disorders, bipolar disorder, or any other 
significant disorder as assessed by clinician judgement and a 
structured clinical interview (MINI 7.0.2)  
2. Diagnosis of complex PTSD based on medical records and 
clinician judgement 

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Post-traumatic Stress Disorder 
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3. Borderline Personality Disorder as demonstrated by both the 
McLean Screening Instrument for Borderline Personality 
Disorder (MSI- BPD) score t 7 and clinical confirmation of 
diagnosis by the study clinician and Medical Monitor 
4. Significant suicide risk as defined by (1) suicidal ideation as 
endorsed on items 4 or 5 on the C-SSRS within the past year, 
during screening or at baseline, or; (2) suicidal behaviours within 
the past year, or; (3) history of serious suicide attempt that 
required a rescuing medical intervention, or; (4) clinical 
assessment of significant suicidal risk during participant 
interview 
5. Current (within the last year) alcohol or substance use disorder 
as informed by DSM-5 assessed via the MINI 7.0.2 at screening 
6. Other personal circumstances and behaviour judged to be 
incompatible with establishment of rapport or safe exposure to 
psilocybin 
7. Exposure to 3,4-methylenedioxymethamphetamine (MDMA), 
psilocybin, or any other psychedelics, such as ayahuasca, 
mescaline, lysergic acid diethylamide (LSD), or peyote in the 
past year 
8. Primary diagnosis of major depressive disorder within 6 months 
of study entry 
9. Exposure to a traumatic experience in the past 3 months 
10. Significant childhood physical or sexual abuse based on clinician 
judgment with the use of CTQ 
11. Enrolment in a psychological therapy programme that will not 
remain stable for the duration of the study. Psychological 
therapies cannot have been initiated within 21 days of baseline  
 
General Medical Exclusion Criteria:  
12. Women 
who 
are 
pregnant, 
nursing 
or 
planning 
a pregnancy. Male and female participants who engage in sexual 
intercourse which could result in pregnancy, must agree to use a 
highly effective contraceptive method (as listed in Section 
10.1.2) throughout their participation in the study. Women of 
childbearing potential must have a negative serum pregnancy 
test at screening and negative urine pregnancy test at baseline  
13. Cardiovascular conditions: recent stroke (< 1year from signing 
of ICF, recent myocardial infarction (<1 year from signing of 
ICF), hypertension (blood pressure >140/90 mmHg) or clinically 
significant arrhythmia within 1 year of signing the ICF 
14. Uncontrolled diabetes for whom hypoglycaemia during a 
prolonged fasting period could be a concern 
15. Seizure disorder 
16. Positive urine drug screen for illicit drugs or drugs of abuse at 
screening and/or baseline. Any positive urine drug test will be 
reviewed with participants to determine the pattern of use and 

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eligibility will be determined at the investigator’s discretion in 
conjunction with the medical monitor 
17. Current enrolment in an interventional study or participation in 
such within 30 days of screening 
18. Abnormal and clinically significant results on vital signs, ECG, 
or laboratory tests at screening and baseline 
19. Any other clinically significant cardiovascular, pulmonary, 
gastrointestinal, hepatic, renal or any other major concurrent 
illness that, in the opinion of the investigator, may interfere with 
the interpretation of the study results or constitute a health risk 
for the participant if he/she takes part in the study 
20. Hypersensitivity to the IMP or any of the excipients  
21. Unwilling to consent to information sharing with the 
participant’s usual general practitioner or family physician 
22. Any other history, medical or psychological conditions that, in 
the opinion of the investigator, impede the ability to establish 
therapeutic alliance leading to psilocybin session 
Exclusion Criteria for subset of participants agreeing to the optional MRI 
scan:  
1. Had a serious head injury, according to their medical history that, 
in the opinion of the investigator will interfere with the 
interpretation of the MRI scan  
2. Have an MRI incompatible implant, including dental metal 
implant, contraceptive coil containing metal, pacemaker, 
vascular clips, artificial heart valves, or any other foreign body 
that might not be safe for MRI 
3. Have tattoos or permanent make up on head, or neck 
4. Being claustrophobic 
5. Have a false limb, brace, or body piercings, hair extensions 
containing metal that cannot be removed 
6. Had an eye injury involving metal  
7. Any other factor deemed to be incompatible with MRI in the 
opinion of the investigator   
Study Drug(s): 
Single, 5 capsule dose of COMP360:  
x 
25 mg COMP360 treatment: 5 x 5mg capsules 
Primary Endpoint:  
The safety and tolerability endpoints include: 
x 
AEs 
x 
12-lead ECGs  
x 
Clinical laboratory tests  
x 
Vital signs 

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Post-traumatic Stress Disorder 
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x 
Suicidality measured via the C-SSRS 
x 
BPRS+ 
Secondary Endpoints: 
x 
Change in CAPS-5 total score from baseline  
x 
Change in PCL-5 total score from baseline 
x 
Change in SDS total score from baseline  
x 
Change in EQ-5D-5L total score from baseline  
x 
Proportion of participants with response (defined as a  15 point 
improvement on the CAPS-5 total score from baseline) 
x 
Proportion of participants with remission (defined as CAPS-5 total 
score  20) 
Exploratory Endpoints: 
x 
Change in PACT total score from baseline  
x 
Change in RAS total score from baseline   
x 
5D-ASC on day 1 
x 
Summary of the Emotional Breakthrough Inventory (EBI) total score 
on day 2 
x 
Participant acceptability of the treatment assessed via a semi-
structured qualitative interview * 
x 
Quantitative and descriptive characterisation of changes in the 
participant narrative as a result of treatment * 
x 
Measures derived from the Measure Health app installed on the 
participant’s smart phone * 
x 
Changes in blood biomarkers after COMP360 therapy, as well as any 
relationship between biomarkers pre- and post-treatment, and clinical 
outcomes 
x 
Brain activation during fMRI tasks relating to trauma-related events 
and an emotional go/no-go task 
*Data from the semi-structured qualitative interview will be assessed outside of 
the Clinical Study Report (CSR) 
Estimand framework 
An estimand framework will not be used for this study since it is a 
descriptive, exploratory study. 

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Statistical Procedures 
Sample Size Determination 
No formal sample size calculation has been performed for this exploratory 
study. 
Analysis Sets 
The Safety Analysis Set will consist of all participants who receive study 
drug.   
The Full Analysis Set (FAS) will consist of all participants in the Safety 
Analysis Set who have at least one post-baseline efficacy assessment.  
Safety Analysis 
The Safety Analysis Set will be used. Safety will be evaluated based on 
AEs, ECG findings, clinical laboratory assessments, vital signs, BPRS+ 
and suicidality (as measured via the C-SSRS).   
Efficacy Analyses 
The FAS will be used. Efficacy endpoints will be summarised using 
descriptive statistics. 
 

Protocol number: COMP 201
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The Safety and Tolerability of COMP360 in Participants with 
Post-traumatic Stress Disorder
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TABLE OF CONTENTS
CLINICAL PROTOCOL APPROVAL FORM .............................................................2
CONFIDENTIALITY AND INVESTIGATOR STATEMENT ...................................3
PROTOCOL SYNOPSIS..................................................................................................4
TABLE OF CONTENTS ................................................................................................12
LIST OF TABLES...........................................................................................................16
LIST OF ABBREVIATIONS .........................................................................................17
1
INTRODUCTION AND RATIONALE .................................................................20
Background ..........................................................................................................20
Study Rationale....................................................................................................20
1.2.1
Pharmacokinetics and Pharmacodynamics.................................................21
1.2.2
Clinical Adverse Event Profile......................................................................21
1.2.3
Dosing Regimen..............................................................................................22
2
STUDY OBJECTIVES ............................................................................................23
Primary .................................................................................................................23
Secondary..............................................................................................................23
Exploratory...........................................................................................................23
3
STUDY ENDPOINTS ..............................................................................................24
Primary .................................................................................................................24
Secondary..............................................................................................................24
Exploratory...........................................................................................................24
4
ESTIMAND FRAMEWORK..................................................................................26
5
STUDY PLAN...........................................................................................................27
Study Design.........................................................................................................27
Study Schematic...................................................................................................29
Schedule of Assessments......................................................................................30
6
POPULATION..........................................................................................................34
Number of Participants .......................................................................................34
Inclusion Criteria.................................................................................................34
Exclusion Criteria ................................................................................................34
Participant Screening ..........................................................................................36
Deviation from Inclusion/Exclusion Criteria ....................................................36
7
STUDY CONDUCT..................................................................................................37
General Instructions ............................................................................................37
Study Procedures by Time Point........................................................................37
7.2.1
Screening Period ............................................................................................37
7.2.2
Baseline Visit – Visit 2 – Day -1....................................................................38
7.2.3
Visit 3 – Day 1 – Administration Session.....................................................40
7.2.4
Visit 4 – Day 2.................................................................................................40
7.2.5
Visit 5 – 1 Week Post-administration...........................................................41
7.2.6
Visit 6 – 2 Weeks Post-administration .........................................................41
7.2.7
Visit 7 – 4 Weeks Post-administration .........................................................42

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7.2.8
Visit 8 – 6 Weeks Post-administration .........................................................42
7.2.9
Visit 9 – 9 Weeks Post-administration .........................................................43
7.2.10
Visit 10 – 12 Weeks Post-administration- End of Study ............................43
Premature Discontinuation.................................................................................44
8
DESCRIPTION OF STUDY PROCEDURES.......................................................45
Efficacy Assessments ...........................................................................................45
8.1.1
Clinician-Administered PTSD Scale for DSM-5.........................................45
8.1.2
PTSD Checklist for DSM-5...........................................................................45
8.1.3
EuroQoL5dimension 5level Scale.................................................................45
8.1.4
Sheehan Disability Scale................................................................................46
8.1.5
Resiliance Adult Scale....................................................................................46
8.1.6
Perceived Ability to Cope with Trauma Scale ............................................46
Safety Assessments...............................................................................................46
8.2.1
Columbia-Suicide Severity Rating Scale .....................................................46
8.2.2
Vital Signs.......................................................................................................47
8.2.3
Electrocardiogram .........................................................................................47
8.2.4
Clinical Laboratory Tests..............................................................................47
8.2.5
Adverse Events...............................................................................................48
8.2.6
Brief Psychiatric Rating Scale – Positive Symptom Subscale....................48
8.2.7
Modified Discontinuation Emergent Signs and Symptoms Scale..............48
Other Assessment Instruments...........................................................................49
8.3.1
Mini International Neuropsychiatric Interview, Version 7.0.2 .................49
8.3.2
McLean Screening Instrument for Borderline Personality 
Disorder ..........................................................................................................49
8.3.3
Life Event Checklist for DSM-5 ...................................................................49
8.3.4
Childhood Trauma Questionnaire ...............................................................49
8.3.5
Semi-structured PTSD management interview...........................................50
8.3.6
Semi-structured qualitative interview..........................................................50
8.3.7
Five Dimensional Altered States of Consciousness Questionnaire............50
8.3.8
Emotional Breakthrough Inventory.............................................................50
8.3.9
Measure Health app.......................................................................................50
8.3.10
Biomarkers measurements............................................................................51
8.3.11
Magnetic Resonance Imaging .......................................................................51
Protocol Deviations ..............................................................................................51
9
INVESTIGATIONAL PRODUCT MANAGEMENT ..........................................52
Description............................................................................................................52
Storage ..................................................................................................................52
Packaging..............................................................................................................52
Dose and Administration.....................................................................................52
Accountability ......................................................................................................53
Compliance...........................................................................................................53
10 CONCOMITANT THERAPY ................................................................................54
Permissible Medications......................................................................................54

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Definition of Women of Childbearing Potential and/or Acceptable 
Contraceptive Methods .......................................................................................54
Prohibited Medications .......................................................................................56
Rescue Medication ...............................................................................................56
11 ADVERSE EVENTS ................................................................................................58
Documenting Adverse Events.............................................................................58
Assessment of Intensity........................................................................................59
Assessment of Causality ......................................................................................59
Action Taken Regarding Investigational Medicinal Product ..........................60
Other Action Taken for Event............................................................................60
Adverse Event Outcome......................................................................................61
Clinical Laboratory Changes..............................................................................61
Overdose ...............................................................................................................61
Adverse Events of Special Interest .....................................................................61
Adverse Event Follow-up ....................................................................................63
12 SERIOUS ADVERSE EVENTS..............................................................................64
Definition of Serious Adverse Event ..................................................................64
Definition of Terms..............................................................................................64
Reporting Serious Adverse Events.....................................................................65
13 STATISTICS.............................................................................................................67
Hypotheses and Treatment Comparisons..........................................................67
Sample Size Considerations ................................................................................67
Analysis Sets .........................................................................................................67
General Considerations.......................................................................................67
Data Handling ......................................................................................................67
13.5.1
Analysis of Efficacy........................................................................................68
13.5.2
Analysis of Safety...........................................................................................68
13.5.3
Participant Disposition, Demographic and Baseline 
Characteristics................................................................................................70
13.5.4
Medical History..............................................................................................70
13.5.5
Prior and Concomitant Medication .............................................................70
Interim Analysis...................................................................................................70
14 ETHICS AND RESPONSIBILITIES.....................................................................71
Good Clinical Practice.........................................................................................71
Data and Safety Monitoring Board....................................................................71
Institutional Review Board/ Independent Ethics Committee ..........................72
Informed Consent ................................................................................................72
Exposure in Utero During Clinical Studies .......................................................72
Records Management ..........................................................................................73
Source Documentation.........................................................................................73
Study Files and Record Retention......................................................................73
15 AUDITING AND MONITORING..........................................................................74
16 AMENDMENTS.......................................................................................................75

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17 STUDY REPORT AND PUBLICATIONS............................................................76
18 STUDY DISCONTINUATION ...............................................................................77
19 CONFIDENTIALITY..............................................................................................78
20 REFERENCES .........................................................................................................79
21 APPENDICES...........................................................................................................81
APPENDIX I – Names of Study Personnel........................................................81
APPENDIX II – Declaration of Helsinki ...........................................................82

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LIST OF TABLES 
Table 8.1 List of clinical laboratory evaluations ...........................................................47 
Table 9.1 
Details of Investigational Medicinal Product (IMP) .............................52 

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LIST OF ABBREVIATIONS 
Abbreviation 
Definition 
5D-ASC 
Five-Dimensional altered states of consciousness  
AE 
adverse event 
AESI 
adverse event of special interest 
ALT 
alanine aminotransferase 
AST 
aspartate aminotransferase 
bpm 
Beats per minute 
BPRS+ 
Brief Psychiatric Rating Scale – Positive symptom subscale 
BTD 
Breakthrough Therapy designation 
CAPS-5 
Clinician-Administered PTSD Scale for DSM-5 
CBT 
Cognitive behavioural therapy 
CFR 
Code of Federal Regulations 
CI 
confidence interval 
COMPASS 
COMPASS Pathfinder Limited 
CSR 
Clinical Study Report 
C-SSRS 
Columbia-Suicide Severity Rating Scale 
CQT 
Childhood Trauma Questionnaire 
DSM-5 
Diagnostic and Statistical Manual of Mental Disorders, 5th edition 
DSMB 
Data and Safety Monitoring Board 
EBI 
Emotional Breakthrough Inventory 
EC50 
half-maximal effective concentration 
ECG 
electrocardiogram 
eCRF 
electronic Case Report Form 
EIU 
Exposure in Utero 
EOS 
End of Study 
EQ-5D-5L 
Euro QoL-5 dimension-5 level 
EQ VAS 
Euro QoL visual analogue scale 
ET 
early termination 
FAS 
full analysis set 
GCP 
Good Clinical Practice 
H 
hour(s) 

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HDPE 
high density polyethylene 
IB 
Investigator’s Brochure 
ICF 
informed consent form 
ICH 
The International Council for Harmonisation of Technical Requirements for 
Pharmaceuticals for Human Use 
IEC 
Independent Ethics Committee 
IMP 
Investigational Medicinal Product 
IRB 
Institutional Review Board 
IV 
intravenous 
Kg 
Kilogram 
L 
Litres 
LEC-5 
Life Events Checklist for DSM-5 
MDD 
major depressive disorder 
mDESS 
Modified Discontinuation Emergent Signs and Symptoms scale 
MedDRA 
Medical Dictionary for Regulatory Activities 
min 
minute(s) 
mg 
milligram 
MINI 7.0.2 
Mini International Neuropsychiatric Interview, Version 7.0.2 
mL  
millilitre 
mmHg 
millimetres of mercury  
MRI 
Magnetic Resonance Imaging 
ng 
Nanogram 
PACT 
Perceived Ability to Cope with Trauma 
PCL-5 
PTSD Checklist for DSM-5 
PRN 
Pro re nata, as needed 
PS 
Prescreen 
PT 
Preferred Term 
PTSD  
Posttraumatic Stress Disorder 
RAS 
Resilience Adult Scale  
SAE 
Serious Adverse Event 
SAF 
Safety Analysis Set 
SAP 
Statistical Analysis Plan 
SD 
standard deviation 
SDS 
Sheehan Disability Scale 

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TRD 
Treatment-resistant depression 
UK 
United Kingdom  
ULN 
upper limit of normal 
US 
United States 

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1
INTRODUCTION AND RATIONALE
The following is a summary of the information found in the current Investigator’s Brochure 
(IB).2
Background
COMP360 is COMPASS’ proprietary formulation of synthetic psilocybin. Psilocybin 
belongs to a class of drugs referred to as psychedelics (meaning ‘mind manifesting’). 
Specifically, psilocybin is considered a 5-hydroxytryptaminergic (serotonergic) 
psychedelic, along with other tryptamines such as dimethyltryptamine (DMT), ergolines 
such as lysergic acid diethylamide (LSD), and phenethylamines such as mescaline.
Study Rationale
PTSD is a serious debilitating condition, highly impactful on quality of life, resulting in 
diminished cognitive and psychosocial functioning, fractured relationships, inability to 
maintain employment, substance abuse, high healthcare utilisation costs, increased 
depression, and suicide risk. People who experience PTSD relive their traumatic 
experience(s) through nightmares and flashbacks, have difficulty sleeping, and feel 
detached or estranged. Despite the fact that symptoms can be severe and long lasting, there 
are currently no effective treatments for PTSD.1
International guidelines recommend psychological interventions (such as trauma-focused 
cognitive behavioural therapy or eye movement desensitisation and reprocessing) as first-
line treatments for PTSD followed by pharmacological approaches, aiming to improve 
mood and reducing hyperarousal.3,4
Serotonin-reuptake inhibitors (SSRIs) are 
recommended by guidelines as second-line treatments, but despite being effective in some 
cases, about 40% of those with PTSD will not improve after treatment.5
The PTSD Psychopharmacology Working Group has recently called for novel, effective 
and efficient trauma-focused interventions and has labelled current treatment outcomes as 
“the Crisis in the Pharmacotherapy of Post-traumatic Stress Disorder”.1  MDMA-assisted 
psychotherapy has recently been designated as a Breakthrough Therapy designation (BTD)
by the Food and Drug Administration (FDA) for PTSD, implying that psychedelic-assisted 
psychotherapies may provide better outcomes for patients than the current standard of care.  
COMP360 therapy has received similar BTD for treatment-resistant depression, a 
condition often comorbid with PTSD. It is therefore reasonable to obtain proof of 
feasibility for COMP360 for PTSD. If demonstrated to be safe and well tolerated, 
COMP360 may offer a powerful alternative to MDMA-assisted psychotherapy in reducing
PTSD symptoms.

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In this study, the aim is to assess the safety and tolerability, and explore efficacy of 
administration of a single dose of COMP360 25 mg under supportive conditions in 
participants with PTSD.      
1.2.1 
Pharmacokinetics and Pharmacodynamics  
The pharmacokinetics of a different form of psilocybin (non-COMP360) were studied in 
12 healthy adult subjects who received single oral doses of 0.3, 0.45, or 0.6 mg/kg at 
minimal intervals of 4 weeks.6 The results suggested rapid luminal and first pass 
dephosphorylation of psilocybin to its active metabolite, psilocin. Plasma exposures of 
psilocin were linear within the dose range tested and the elimination half-life of psilocin 
was 3 h (standard deviation [SD] ± 1.1 h). Variation in psilocin exposure was not predicted 
by body weight; therefore, a fixed oral psilocybin dose of 25 mg is expected to result in 
psilocin exposure (based on the area under the curve [AUC] and Cmax) similar to that 
demonstrated after an individualised 0.3 mg/kg oral dose. At the 0.3 mg/kg dose, the AUC 
was 140 Pg h/L (interquartile range [IQR] 102 - 175), the plasma psilocin Cmax was 16 
Pg/L (IQR 14.5-17.2) and Tmax was 2.03 h (1.15 - 2.07). No psilocybin was found in plasma 
or urine, and renal clearance of intact psilocin accounted for less than 2% of the total 
clearance. An extended elimination phase in some subjects suggests potential for 
hydrolysis of psilocin glucuronide metabolite. 
Available results of COMP360 and previously published information on different forms of 
psilocybin from in vitro assays and rodent studies demonstrate broadly similar 
pharmacokinetics to human studies after a single dose. 
The subjective intensity of the psychedelic effects of a different form of psilocybin (non-
COMP360) have been shown to correlate with plasma levels of psilocin and its levels of 
occupancy of 5-HT2A receptors.7 The psychedelic effects of psilocybin can be blocked with 
ketanserin, a 5-HT2A receptor antagonist.8  Thus, the pharmacokinetics of psilocin and 
concomitant activation of 5-HT2A receptors appears to be closely associated with the 
psychedelic effects of psilocybin. 
1.2.2 
Clinical Adverse Event Profile 
The safety of COMP360 should be considered in terms of benefit and risk. Within the 
context of COMP360 administration in a controlled setting with psychological support, a 
participant may report visual or auditory disturbances, perceptual distortions, altered sense 
of time, and other changes in mood or affect amongst other neuropsychiatric observations 
which have been previously described.15 These effects are both expected, and may be a 
necessary component of therapeutic response. Investigators must follow regulatory 
guidance for AE reporting which addresses untoward medical occurrences associated with 
the use of a drug in humans, whether or not considered drug related. An AE can be any 
unfavourable and unintended sign (eg an abnormal laboratory finding), symptom, or 
disease temporally associated with the use of a drug, without any judgment about causality. 

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Results from COMPASS’ completed trial in healthy volunteers (COMP 002, EudraCT 
number: 20180999878-30) suggests that COMP360 is generally well tolerated. There were 
no SAEs and no AEs led to study withdrawal. In total, 511 TEAEs were reported over the 
12-week study duration across the 89 participants. Of the 511 TEAEs, the majority had an 
onset and resolution on day 1. Of the 403 TEAEs that started on the day of dosing, 343 
(85.4%) were resolved the same day. 
1.2.3 
Dosing Regimen 
This study will evaluate a 25 mg single COMP360 dose administered under supportive 
conditions.  
Carhart-Harris- successfully evaluated two oral doses of psilocybin (non-COMP360) (10 
mg and 25 mg) administered seven days apart to patients with unipolar TRD. Minimal AEs 
were reported in this study.9 Work by the Griffiths group showed that under supportive 
conditions, psilocybin at doses of 20 to 30 mg/70 kg can dose dependently occasion 
mystical- -type experiences.10 The doses successfully explored in cancer patients with 
mood and/or anxiety symptoms range between 14-30 mg/70 kg. 10-12  
COMPASS is currently running a phase IIb study to measure COMP360 efficacy on TRD 
symptoms using doses of 1 mg, 10 mg, and 25 mg. Considering that depression is highly 
comorbid with PTSD, we expect a 25 mg dose to be adequate in this population for safety 
purposes.   

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2
STUDY OBJECTIVES
Primary
To assess the safety and tolerability of COMP360 administered under supportive 
conditions in PTSD participants
Secondary
x
To assess the efficacy of COMP360 administered under supportive conditions in 
reducing PTSD symptoms
x
To assess the effects of COMP360 administered under supportive conditions on quality 
of life and participant functional impairment
Exploratory 
x
To assess participants subjective experience of COMP360 administered under 
supportive conditions
x
To assess participants perceived growth and resilience after COMP360 therapy
x
To evaluate the impact of COMP360 on real life functional activity estimated from 
passive data streams collected on the Measure Health app on participants' mobile phones 
x
Natural Language Processing on the participant narrative during the interactions with 
the therapist
x To assess the influence of COMP360 therapy on blood biomarkers
x To assess the influence of COMP360 therapy on brain activity 
  

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STUDY ENDPOINTS 
Primary
The safety and tolerability endpoints include:
x
AEs
x
12-lead ECGs 
x
Clinical laboratory tests 
x
Vital signs
x
Suicidality measured via the C-SSRS
x
Brief Psychiatric Rating Scale – Positive symptom subscale (BPRS+)
Secondary
x
Change in CAPS-5 total score from baseline 
x
Change in PCL-5 total score from baseline
x
Change in SDS total score from baseline 
x
Change in EQ-5D-5L total score from baseline 
x
Proportion of participants with response (defined as a  15 point improvement on the 
CAPS-5 total score from baseline)
x
Proportion of participants with remission (defined as CAPS-5 total score  20)
Exploratory 
x
Change in PACT total score from baseline 
x
Change in RAS total score from baseline  
x
5D-ASC on day 1
x
Summary of the Emotional Breakthrough Inventory (EBI) total score on day 2
x
Participant acceptability of the treatment assessed via a semi-structured qualitative 
interview *
x
Quantitative and descriptive characterisation of changes in the participant narrative as 
a result of treatment *
x
Measures derived from the Measure Health app installed on the participant’s smart 
phone *

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x Changes in blood biomarkers after COMP360 therapy, as well as any relationship 
between biomarkers pre- and post-treatment, and clinical outcomes 
x Brain activation during fMRI tasks relating to trauma-related events and an emotional 
go/no-go task 
 
*Data from the semi-structured qualitative interview will be assessed outside of the CSR. 
 
 

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4 ESTIMAND FRAMEWORK 
An estimand framework will not be used for this study since it is a descriptive, exploratory 
study. 
 

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5
STUDY PLAN
Study Design
This is a phase II, multicentre, fixed-dose open label trial. The study population will include 
adult men and women outpatients, 18 years of age and older meeting Diagnostic and 
Statistical Manual of Mental Disorders (5th Edition; DSM-5) diagnostic criteria for PTSD 
after a traumatic event experienced during in adulthood. 
After signing the informed consent form (ICF), participants will be assessed for their 
eligibility with the Mini International Neuropsychiatric Interview, version 7.0.2 (MINI 
7.0.2), the PTSD Checklist for DSM-5 (PCL-5), Life Events Checklists for DSM-5 (LEC-
5), the Childhood Trauma Questionnaire (CTQ) and the Columbia- Suicide Severity Rating 
Scale (C-SSRS). Those who meet the eligibility criteria will enter the screening period. 
Additionally, a medical history, an electrocardiogram (ECG), blood tests, and vital signs 
will be obtained. Participants will be offered the option of enrolling in the neuroimaging 
component of the study. Participation in this part of the study is optional, and participants 
who do not consent to neuroimaging will not be excluded from the study.  If participants 
consent to neuroimaging, they will be assessed for additional eligibility criteria for the 
Magnetic Resonance Imaging (MRI) scan. 
During the screening period, participants who are on antidepressant and/or antipsychotic 
medications will be expected to complete tapering of these medications at least 2 weeks 
prior to baseline. Participants will be given a choice of the tapering rate. During the tapering 
period all participants will be supported by the study clinician. 
Once the participant has been evaluated as eligible, they are invited to enter the screening 
period visits. During the first of these visits the participant begins tapering off their 
antidepressant and/or antipsychotic medications, if appropriate. The participant must 
complete the taper within the first 4 weeks of this period, prior to 2 weeks completely off 
antidepressant and/or antipsychotic medications, before the baseline visit.
The designated study team member will be in frequent contact with the participants to 
monitor for withdrawal and worsening of symptoms. The participant will meet with a 
therapist for a minimum of 3 visits during screening. These are safety sessions and will 
contribute to the participant’s preparation for the COMP360 administration session.
All participants will be evaluated for safety at the clinic weekly for a minimum of three 
weeks prior to COMP360 administration to ensure safe discontinuation of current 
antidepressant therapy required by the protocol. Participants’ companions (carers, friends, 
or family members) may be educated about the signs of worsening of PTSD and suicidality 
and instructed on ways to contact the study team in case of significant worsening. During 
these visits the C-SSRS, the Modified Discontinuation Emergent Signs and Symptoms 
Scale (mDESS), and any changes in medications since the previous visit will be obtained 
in addition to other assessments at the study clinician’s discretion. The designated study 
team member will contact the participant by phone calls in between in clinic visits during 
screening period to monitor for withdrawal and worsening of symptoms.

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The day before the administration session, the participants will undergo a baseline 
assessment (3 to 6 weeks after beginning screening period) that will consist of the 
Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), Sheehan Disability Scale 
(SDS), EuroQuol-5 Dimensions- 5 Levels (EQ-5D-5L), C-SSRS, BPRS+, Perceived 
Ability to Cope with Trauma (PACT), Resilience Adult Scale (RAS), a semi-structured 
interview on the management of their PTSD, vital signs, urinalysis, urine drug screen, and 
urine pregnancy test (only for women of childbearing potential). After baseline data are 
collected and entered in the Electronic Data Capture (EDC), the Clinical Assessment 
Technologies Team (CAT) team will complete a final review to ensure the participant’s 
continued eligibility. Participants cannot be progressed to the administration session until 
this approval is received. Full descriptions of the activities carried out during the therapist 
sessions can be found in the Therapist Manual. Those who agreed to take part to the 
optional neuroimaging component of the study and met the eligibility criteria will be 
offered an MRI scan. To reduce participant burden on baseline visit, the MRI scan can be 
organised within 7 days prior to the baseline visit. The investigator will be responsible of 
confirming eligibility of the participant before MRI.  
The following day, the participants will attend the clinic for the dosing session that will 
last approximately 6-8 hours and will be supported by two designated trained therapists. 
Participants will receive 25 mg COMP360. A full description of the activities of the 
administration session is found in the Therapist Manual. After the acute effects of 
COMP360 pass, participants will complete the Five-Dimensional Altered States of 
Conciousness (5D-ASC), and will be evaluated for safety and accompanied home. On the 
following day, participants will be seen in person for a safety check, assessment of 
suicidality, and to discuss their experience during the dosing session (integration). During 
this visit, participants will complete a semi-structured interview on the acceptability of the 
therapeutic intervention and the severity of PTSD symptoms will be evaluated using the 
PCL-5. All sessions between the therapists and the participant may be audio recorded for 
adherence monitoring and quality assurance. Audio and video recording of the sessions are 
subject to participant consent. Participants who do not consent to either or all recordings 
will not be excluded from the study.  
All participants will be asked to remain off medications for their PTSD symptoms for at 
least 4 weeks following the administration session. Rescue medications are allowed as 
noted in the protocol. Participants who restart their medications during the first 4 weeks 
after the dosing session will be assessed for reasons of resuming their medications and 
followed until 12 weeks post COMP360 administration. Participants will be seen at the 
clinic for screening (plus a minimum of 3 safety visits), baseline, day 1, day 2, week 1, 
week 2, week 4, and week 12 visits. Participants will also be contacted for a remote follow-
up at week 6 and week 9. The option of an in clinic visit at weeks 6 and 9 will also be 
available. See Section 5.3 for a full schedule of assessments. Participants who agreed to 
the optional neuroimaging component of the study will be offered an MRI scan at week 4. 
The study schematic is presented in Section 5.2 and the schedule of assessments is 
presented in Section 5.3.

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Study Schematic

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Screening 
(2 weeks 
Prior 
COMP360) 
Baseline 
 
Time Since COMP360 Treatment 
 
Screen 
Visit1 
Screening 
Period 
 
Day -1 
Administration 
Session  
(Day 1) 
Day 2 
Week 1 
Week 2 
Week 4 
Week 6 
Week 9 
Week 
12 
(ET) 
Allowable Window 
N/A  
weekly  
N/A  
  7 days 
none 
± 1 day 
 ± 1 day 
± 1 day 
± 3 days 
± 3 days 
± 7 days 
Visit 
1 
1a, 1b, etc 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Location Visit 
Clinic 
Clinic2 
Clinic 
Clinic 
Clinic 
Clinic 
Clinic 
Clinic 
Remote/Clinic 
Remote/Clinic 
Clinic 
Height  
ض
 
Urinalysis6 
ض 
 
ض 
 
 
 
 
 
Urine drug screen6 
ض 
 
ض 
 
ض 
ض 
ض
ض 
ض
ض
ض 
Urine pregnancy 
test7 
 
 
ض 
 
ض 
 
 
 
 
 
 
Serum pregnancy 
test7 
ض
 
 
 
 
 
 
Clinical Laboratory 
tests 6 
ض 
 
ض 
 
ض 
 
 
ض 
ض 
Biomarkers analysis 
 
ض9
 
 
 
ض
ض
MRI scan9 
 
ض
 
 
 
ض
Activate/deactivate 
Measure Health 9 
ض
 
 
 
 
 
 
ض 
Prior/Concomitant 
Medication Review 
ض
ض
ض
ض
ض
ض
ض
ض
ض
ض
ض
Documentation of 
contraceptive 
method to be used7 
ض
IMP administration 
 
 
ض 
 

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Screening 
(2 weeks 
Prior 
COMP360) 
Baseline 
 
Time Since COMP360 Treatment 
 
Screen 
Visit1 
Screening 
Period 
 
Day -1 
Administration 
Session  
(Day 1) 
Day 2 
Week 1 
Week 2 
Week 4 
Week 6 
Week 9 
Week 
12 
(ET) 
Allowable Window 
N/A  
weekly  
N/A  
  7 days 
none 
± 1 day 
 ± 1 day 
± 1 day 
± 3 days 
± 3 days 
± 7 days 
Visit 
1 
1a, 1b, etc 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Location Visit 
Clinic 
Clinic2 
Clinic 
Clinic 
Clinic 
Clinic 
Clinic 
Clinic 
Remote/Clinic 
Remote/Clinic 
Clinic 
Semi-structured 
qualitative interview  
 
 
ض
ض
 
Abbreviations: AE, adverse event; BPRS+, Brief Psychiatric Rating Scale – Positive Symptom subscale; CAPS-5, Clinician Administered PTSD Scale for DMS-5; C-SSRS, Columbia-Suicide Severity 
Rated Scale; CTQ, Childhood Trauma Questionnaire; EBI, Emotional Breakthrough Inventory; ECG, electrocardiogram; EQ5D-5L, EuroQoL 5dimension 5-levels; ET, early termination; IMP, 
Investigational Medicinal Product; mDESS=Modified Discontinuation Emergent Signs and Symptoms scale; MRI, Magnetic Resonance Imaging; MSI-BPD, McLean Screening Instrument for Borderline 
Personality Disorder; LEC-5, Life Events Checklist for DSM-5; MINI, Mini International Neuropsychiatric Interview; PACT, Perceived Ability to Cope with Trauma scale; PCL-5, PTSD Checklist for 
DSM-5; SDS, Sheehan Disability Scale; 5D-ASC. Five Dimensional Altered States of Consciousness 
 
1  If additional visits are needed to ensure adequate time for discontinuation of prior antidepressant therapy, visits should occur weekly prior to the dosing session (V3). At subsequent screening visits (V1a, 
V1b, etc), medications taken and any changes in medications since the previous visit and C-SSRS will be obtained, in addition, to other assessments at the study clinician’s discretion. Assessments may 
be performed over several days, but all scales should be completed on the same day. 
2 Telephone check-ins will be completed in between clinic visits. 
3 The “Last 12 Months” version will be administered at screening and the “Since Last Visit” version will be administered at all other visits. 
4This assessment will be administered at the end of the admnistration session. 
5 This assessment will be administered before COMP360 dosing. 
6 See Section 8.2.4 for complete list of required tests to be performed. 
7 For women of child-bearing potential only. 
8 Only clinical laboratory tests will be tested at this visit. 
9 Optional components of the study.  
10 Baseline MRI scan can be completed within  7 days prior to baseline visit. 
11Participants will have two preparation sessions during the screening period and one on day -1. 
12Psychoeducational information will be provided by the therapist during the preparation sessions in the screening period. 
13 Collection starting from V1b through to Baseline for those participants requiring withdrawal from prohibited medications. 
14The EBI must be performed after integration on day 2. 

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6
POPULATION
Number of Participants
A total of up to 20 participants will be included with the below eligibility criteria.
Inclusion Criteria
To be eligible for the study, participants must meet the following criteria:
1. Signed ICF
2. 18 years of age or older at screening
3. Meet DSM-5 criteria for current PTSD resulting from a trauma experienced during 
adulthood measured via the PCL-5 in combination with the LEC-5 at screening 
4. Meet DSM-5 criteria for current PTSD resulting from a trauma experienced during 
adulthood as assessed by the CAPS-5, with a minimum score of 25 at baseline
5. Able to identify a next of kin who is willing and able to be reached by the 
investigators in case of emergency 
6. Have successfully discontinued all prohibited medications at least two weeks prior to 
baseline visit. For fluoxetine (Prozac), immediate cessation at screening period visit 
1a followed by at least four weeks of run-in will be required prior to baseline
7. Able to complete all protocol required assessment tools without any assistance or 
alteration to the copyrighted assessments, and to comply with all study visits
Inclusion Criteria for subset of participants agreeing to the optional MRI scan:
1. Have consented to take part in the neuroimaging component of the study
Exclusion Criteria
Exclusion of potentially confounding psychiatric diseases and therapies:
1. Current or past history of schizophrenia, obsessive compulsive disorder, personality 
disorders, bipolar disorder, or psychotic disorder as assessed by clinician judgement 
and a structured clinical interview (MINI 7.0.2)
2. Diagnosis of complex PTSD based on medical records and clinician judgement
3. Borderline Personality Disorder as demonstrated by both the McLean Screening 
Instrument for Borderline Personality Disorder (MSI- BPD) score t 7 and clinical 
confirmation of diagnosis by the study clinician and Medical Monitor
4. Significant suicide risk as defined by (1) suicidal ideation as endorsed on items 4 or 5 
on the C-SSRS within the past year, at screening or at baseline, or; (2) suicidal 
behaviours within the past year, or; (3) history of serious suicide attempt that required 
a rescuing medical intervention, or; (4) clinical assessment of significant suicidal risk 
during participant interview
5. Current (within the last year) alcohol or substance use disorder as informed by DSM-5 
assessed via the MINI 7.0.2 at screening
6. Other personal circumstances and behaviour judged to be incompatible with 
establishment of rapport or safe exposure to psilocybin

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7. Exposure to 3,4-methylenedioxymethamphetamine (MDMA), psilocybin, or any other 
psychedelics, such as ayahuasca, mescaline, lysergic acid diethylamide (LSD), or 
peyote in the past year 
8. Primary diagnosis of major depressive disorder within 6 months of study entry 
9. Exposure to a traumatic experience in the past 3 months 
10. Significant childhood physical or sexual abuse based on clinician judgment with the 
use of CTQ 
11. Enrolment in a psychological therapy programme that will not remain stable for the 
duration of the study. Psychological therapies cannot have been initiated within 21 days 
of baseline  
 
General Medical Exclusion Criteria:  
1. Women who are pregnant, nursing or planning a pregnancy. Male and female 
participants who engage in sexual intercourse which could result in pregnancy, must 
agree to use a highly effective contraceptive method (as listed in Section 10.1.2) 
throughout their participation in the study. Women of childbearing potential must have 
a negative serum pregnancy test at screening and negative urine pregnancy test at 
baseline  
2. Cardiovascular conditions: recent stroke (< 1year from signing of ICF, recent 
myocardial infarction (<1 year from signing of ICF), hypertension (blood pressure 
>140/90 mmHg) or clinically significant arrhythmia within 1 year of signing the ICF 
3. Uncontrolled diabetes for whom hypoglycaemia could be a concern 
4. Seizure disorder 
5. Positive urine drug screen for illicit drugs or drugs of abuse at screening and/or 
baseline. Any positive urine drug test will be reviewed with participants to determine 
the pattern of use and eligibility will be determined at the investigator’s discretion in 
conjunction with the medical monitor 
6. Current enrolment in an interventional study or participation in such within 30 days of 
screening 
7. Abnormal and clinically significant results on vital signs, ECG, or laboratory tests at 
screening 
8. Any other clinically significant cardiovascular, pulmonary, gastrointestinal, hepatic, 
renal or any other major concurrent illness that, in the opinion of the investigator, may 
interfere with the interpretation of the study results or constitute a health risk for the 
participant if he/she takes part in the study 
9. Hypersensitivity to the IMP or any of the excipients  
10. Unwilling to consent to information sharing with the participant’s usual general 
practitioner or family physician 
11. Any other history, medical or psychological conditions that, in the opinion of the 
investigator, impede the ability to establish therapeutic alliance leading to psilocybin 
session 
Exclusion Criteria for subset of participants agreeing to the optional MRI scan:  
1. Had a serious head injury, according to their medical history that, in the opinion of the 
investigator will interfere with the interpretation of the MRI scan  

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2. Have an MRI incompatible implant, including dental metal implant, contraceptive coil 
containing metal, pacemaker, vascular clips, artificial heart valves, or any other foreign 
body that might not be safe for MRI
3. Have tattoos or permanent make up on head, or neck
4. Being claustrophobic
5. Have a false limb, brace, or body piercings, hair extensions containing metal that cannot 
be removed
6. Had an eye injury involving metal 
7. Any other factor deemed to be incompatible with MRI in the opinion of the investigator
Participant Screening 
Participants will be recruited primarily from the community and referring healthcare providers. 
Those participants considered potentially eligible for the study will be assessed to confirm 
eligibility after the participant has signed an ICF. Rescreening of participants considered not 
eligible for the study will be allowed. Decisions to rescreen will be discussed on a case-by-case 
basis with the Medical Monitor and study investigators. Participants who consent to take part 
in the optional neuroimaging portion of the study will be assessed to confirm eligibility with 
additional criteria specific for MRI. If the participant does not meet the eligibility criteria for 
the neuroimaging, they will not be able to participate to the MRI scanning, but they will still 
take part in the main study. 
Deviation from Inclusion/Exclusion Criteria
No deviations will be permitted from the inclusion or exclusion criteria. The investigator may 
call the Medical Monitor to discuss the eligibility of any given participant.

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7
STUDY CONDUCT
The procedures to be performed throughout the study are outlined in the Schedule of 
Assessments (Section 5.3). A detailed description of each assessment may be found in Section 
8.2. 
General Instructions
Participants will be outpatients and will be recruited primarily from the community and 
referring healthcare providers. Those participants considered eligible for the study will be 
further assessed to confirm eligibility after the participant has signed an ICF.
Study Procedures by Time Point  
7.2.1
Screening Period
The participant will be seen initially to evaluate suitability for the study. All participants will 
be seen at the clinic weekly for a minimum of three weeks prior to the baseline visit to ensure 
safe discontinuation of current antidepressant/antipsychotic medications required by the 
protocol, and to conduct psychoeducation. At the first screening visit, the following 
assessments will be performed and recorded:
o
ICF
o
Medical history
o
Prior and current medications; the participant will be tapered from prohibited 
medications (see Section 10.3), if any, under the supervision of the study clinician
o
Review of inclusion/exclusion criteria (Section 6)
o
MINI version 7.0.2
o
MSI-BPD
o
PCL-5
o
LEC-5
o
CTQ
o
C-SSRS (Last 12 months)
o
Vital signs (ie, supine, after at least five mins of rest, diastolic and systolic blood 
pressure, pulse, and body temperature)
o
Weight
o
Height

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o 12-lead ECG 
o Blood and urine samples for: 
 Clinical laboratory tests  
 Urinalysis 
 Urine drug screen 
 Serum pregnancy test for all women of childbearing potential 
o Document contraceptive method to be used by the participant 
o If the participant opts to participate in the Measure Health app, the app will be uploaded 
on the participant’s mobile phone and activated  
All participants will undergo two in-person preparatory sessions during the screening period, 
where the designated therapist will use psychoeducational material. More details on the 
preparatory sessions are in the Therapist Manual.  
Once a participant completes all screening assessments and all screening data is entered into 
the EDC, the Medical Monitor, and CAT Team will review data entered and issue approval, if 
the patient is eligible. Once approval is issued, the participant should then be invited for a 
screening V1a visit. The V1a visit is the point at which the patient begins tapering off their 
antidepressant and/or antipsychotic medications, if appropriate. The participant must complete 
the taper within the first 4 weeks of this period, prior to 2 weeks completely off antidepressant 
and/or antipsychotic medications, before baseline. The tapering period used in the study is set 
at the industry standard for depression trials. The study team will complete telephone check-
ins in between the weekly in clinic visits. 
At subsequent screening period visits (V1a, V1b, etc), medications taken and any changes in 
medications since the previous visit, and the C-SSRS and mDESS (if the participant is 
withdrawing from prohibited medications) will be obtained.  
 
7.2.2 
Baseline Visit – Visit 2 – Day -1 
The baseline visit should occur within 3 to 6 weeks after beginning of screening period. At 
baseline visit, the participant’s eligibility will be confirmed by reviewing the 
Inclusion/Exclusion Criteria (Sections 6.2 and 6.3) and updating medical history.  
The following procedures will be performed and recorded at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+  
o CAPS-5 

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o PCL-5 
o mDESS (if applicable) 
o EQ-5D-5L  
o SDS 
o RAS 
o PACT 
o Semi-structured PTSD management interview 
o Vital signs (ie supine, after at least five mins of rest, diastolic and systolic blood 
pressure, pulse, and body temperature) 
o Blood and urine samples for: 
 Clinical laboratory tests  
 Biomarkers, if the participant opts to participate in this part of the study  
 Urine drug screen 
 Urinalysis 
 Urine pregnancy test for all women of childbearing potential 
o Medications taken and any changes in medications since the previous visit 
o AEs and Serious AEs (SAEs) (Sections 11 and 12) 
If the participant continued to meet the eligibility criteria, the trained therapist will review 
psychoeducational material and the anticipated psilocybin session with the participant. If the 
participant remains eligible, arrangements will be made for the participant to return to the study 
site for IMP administration the next day. After baseline data is entered into EDC, the CAT 
team will complete a final review to ensure the participant’s continued eligibility. Participants 
cannot be progressed to the administration session until this approval is received. 
If the participant opts to participate in the neuroimaging part of the study, specific eligibility 
criteria will be reviewed by the investigator (Section 6). If considered eligible, the participant 
will undergo an MRI scan (within ื7 days prior to baseline). 
 

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7.2.3 
Visit 3 – Day 1 – Administration Session 
The administration session should occur the day after baseline visit. During this session (the 
day of COMP360 administration), the following are to be obtained: 
o Vital signs (ie supine after at least five mins of rest diastolic and systolic blood pressure, 
pulse, body temperature, and respiratory rate). Before dosing  
o Administration of study drug (Section 9.4). The dosing session may be video recorded 
for training and adherence monitoring. A full description of the activities of the dosing 
session is found in the Therapist Manual. After approximately 6-8 h, participants will 
be assessed for safety and to ensure the acute drug effects have subsided before being 
accompanied home.  
o C-SSRS (Since Last Visit), after dosing 
o BPRS+, after dosing 
o 5D-ASC, after dosing  
o Medications taken and any changes in medications since the previous visit 
o AEs and SAEs (Sections 11 and 12) after dosing 
7.2.4 
Visit 4 – Day 2  
On the day following IMP administration, the participant will return to the study site for a 
safety check and to discuss their experience during the administration session. The following 
will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o PCL-5 
o Vital signs (ie, supine, after at least five mins of rest, diastolic and systolic blood 
pressure, pulse, and body temperature) 
o 12-lead ECG 
o Blood samples for clinical laboratory tests 
o Urine drug screen  
o Urine pregnancy test for all women of childbearing potential 
o Medications taken and any changes in medications since the previous visit 

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o AE and SAE (Sections 11 and 12) 
o Semi-structured qualitative interview  
o Integration session with the trained therapist 
o EBI. Note that this assessment must be completed after the integration session 
Participants will be asked to remain off medications for PTSD until after week 4. 
7.2.5 
Visit 5 – 1 Week Post-administration 
The participant will visit the clinic 1 week (± 1 day) following study drug administration; the 
following assessments will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o PCL-5 
o Urine drug screen 
o Medications taken and any changes in medications since the previous visit 
o AE and SAE (Sections 11 and 12)  
o Integration session with the trained therapist 
Participants will be reminded to remain off medications for PTSD until after week 4. 
7.2.6 
Visit 6 – 2 Weeks Post-administration 
The participant will will visit the clinic 2 weeks (± 1 day) following study drug administration; 
the following assessments will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o PCL-5 
o Urine drug screen 
o Medications taken and any changes in medications since the previous visit 
o AE and SAE (Sections 11 and 12)  
o Integration session with the trained therapist 

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Participants will be reminded to remain off medications for PTSD until after week 4. 
 
7.2.7 
Visit 7 – 4 Weeks Post-administration 
The participant will visit the clinic 4 weeks (± 1 day) following study drug administration; the 
following assessments will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o CAPS-5 
o PCL-5 
o EQ-5D-5L  
o SDS 
o RAS 
o PACT 
o Blood samples for:  
 Clinical laboratory tests  
 Biomarkers, if the participant opts to participate in this part of the study 
o Urine drug screen 
o Medications taken and any changes in medications since the previous visit 
o AE and SAE (Sections 11 and 12)  
If the participant opts to participate in the neuroimaging part of the study, they will undergo 
an MRI scan. 
 
7.2.8 
Visit 8 – 6 Weeks Post-administration 
The participant will be telephoned by site staff 6 weeks (± 3 days) following study drug 
administration; the following assessments will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 

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o PCL-5 
o Urine drug screen 
o Medications taken and any changes in medications since the previous visit 
o AE and SAE (Sections 11 and 12)  
7.2.9 
Visit 9 – 9 Weeks Post-administration 
The participant will be telephoned by site staff 9 weeks (± 3 days) following study drug 
administration; the following assessments will be obtained at this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o PCL-5 
o Urine drug screen 
o Medications taken and any changes in medications since the previous visit 
o AE and SAE (Sections 11 and 12)  
7.2.10 
Visit 10 – 12 Weeks Post-administration- End of Study 
The participant will visit the clinic 12 weeks (± 7 day) following study drug administration for 
the End of Study visit (EOS); this visit is also to be completed if the participant is discontinued 
from the study early (early termination [ET]). The following assessments will be obtained at 
this visit: 
o C-SSRS (Since Last Visit) 
o BPRS+ 
o CAPS-5 
o PCL-5 
o EQ-5D-5L  
o SDS 
o RAS 
o PACT 
o Semistructured-qualitative interview 

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o
Blood samples for: 

Clinical laboratory tests

Biomarkers, if the participant opts to participate in this part of the study
o
Urine drug screen
o
Deactivate Measure Health app, if appropriate
o
Medications taken and any changes in medications since the previous visit
o
AE and SAE (Sections 11 and 12) 
Premature Discontinuation
If a participant’s participation in the study is terminated prematurely for any reason, the reason 
for such ET should be documented and the V10 (EOS) procedures should be performed as 
noted in Section 7.2.10.
A termination form should be completed for every participant who is enrolled, whether the 
participant completes the study or not. The reason for any ET should be indicated on this form; 
as much information should be provided as possible. The primary reason for a participant 
discontinuing early should be selected from the following standard categories of ET:
x
Screen Failure: Participant does not qualify to participate in the study.
x
Lack of efficacy
x
Adverse Event: Clinical or laboratory events occurred that, in the medical judgment of the 
investigator for the best interest of the participant, are grounds for discontinuation. This 
includes serious and nonserious AEs regardless of relation to the IMP.
x
Death: The participant died.
x
Withdrawal of Consent: The participant desired to withdraw from further participation in 
the study in the absence of an investigator-determined medical need to withdraw. If the 
participant gave a reason for withdrawing, it should be recorded.
x
Lost to Follow-up: The participant stopped coming for visits and study personnel were 
unable to contact the participant.
x
Non-compliance: The participant was non-compliant with study visits or procedures. 
x
Other: The participant was discontinued for a reason other than those listed above, such 
termination of the study by the sponsor. 

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8
DESCRIPTION OF STUDY PROCEDURES
Efficacy Assessments 
8.1.1
Clinician-Administered PTSD Scale for DSM-5
The CAPS-5 is the gold standard clinician rated assessment for PTSD. It consists of 30 items 
and can be used for diagnostic purposes as well as monitoring PTSD symptoms severity over 
time. Each item could be rated as 0=absent, 1=mild/subthreshold, 2=moderate/subthreshold, 
severe/markedly elevated, 4=extreme/ incapacitating. At baseline visit the last month version 
of CAPS-5 will be used for diagnostic purposes. The last month version of the assessment will 
be administered to monitor participant symptoms improvement after treatment at weeks 4 and 
12.13
8.1.2
PTSD Checklist for DSM-5 
The PCL-5 is a 20-item self-reported scale, used for provisional PTSD diagnosis, screening 
and symptoms monitoring purposes. The participant will complete the past month version of 
this assessment at screening, scoring the severity of their symptoms on a 5-points Likert scale 
where 0 = not at all and 4 = extremely.14 The screener should help the participant understanding 
this scale and in its correct completion to ensure the PCL-5 is used to measure the relevant 
Criterion A for the trauma. The past day version of the assessment will be used at day 2. The 
past week version of the assessment will be administered at baseline and weeks 1, 2, 4, 6, 9, 
and 12.
8.1.3
EuroQoL5dimension 5level Scale
The EQဩ5Dဩ5L was introduced by the EuroQoL Group in 2009.21,22 The EQ-5D-5L consists of 
2 sections: the EQ-5D-5L descriptive system and the EQ visual analogue scale (EQ VAS). 
The descriptive system comprises five dimensions: mobility, self-care, usual activities, 
pain/discomfort, and anxiety/depression. Each dimension has five levels: no problems, slight 
problems, moderate problems, severe problems and extreme problems. The participant is asked 
to indicate his/her health state by ticking the box next to the most appropriate statement in each 
of the five dimensions. This decision results in a 1-digit number that expresses the level 
selected for that dimension. The digits for the five dimensions can be combined into a 5-digit 
number that describes the participant’s health state.
The EQ VAS records the participant’s self-rated health on a vertical VAS, where the endpoints 
are labelled ‘The best imaginable health state’ and ‘The worst imaginable health state’. The 
VAS can be used as a quantitative measure of health outcome that reflect the participant’s own 
judgement. 
The EQ-5D-5L will be obtained at baseline, week 4, and week 12 visits.

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8.1.4
Sheehan Disability Scale
The SDS is a brief, 5-item inventory that assesses functional impairment in work/school, social 
life, and family life. The total score ranges from 0 to 30 with 0 representing no impairment and 
30 representing severe impairment. The last two items of the scale (Days Lost and Days 
Unproductive) do not count toward the total score. Each domain is rated on a 10-point visual 
analogue scale (VAS).15 The SDS will be completed by participants at baseline, week 4 and 
week 12.
8.1.5
Resiliance Adult Scale 
The RAS was developed to capture a set of fundamental protective factors based on resilience 
research. It includes 33 items, in a six-factors structure including (1) perception of self, (2) 
planned future, (3) social competence, (4) structured style, (5) family cohesion, (6) social 
recourses.16
8.1.6
Perceived Ability to Cope with Trauma Scale
The PACT scale is a self-reported, 20 items scale, organised in two sub-scales, (1) Forward 
focus and (2) Trauma focus. The first subscale measures the ability of the individual to move 
beyond their trauma, while the second measures the perceived ability to focus on processing 
the trauma. Overall the scales provides a quantification of the individual’s coping flexibility.17
Safety Assessments
8.2.1
Columbia-Suicide Severity Rating Scale
The C-SSRS will be used to assess suicide potential or tendency as a study entry criterion and 
monitored throughout the study.
The C-SSRS is a semi-structured interview designed to assess the severity and intensity of 
suicidal ideation, suicidal behaviour, and non-suicidal self-injurious behaviour over a specified 
time period. The measurement of suicidal ideation is based on five “yes” or “no” questions 
with accompanying descriptions arranged in order of increasing severity. If the patient answers 
“yes” to either questions 1 or 2, the intensity of ideation is assessed in five additional questions 
related to frequency, duration, controllability, deterrents, and reasons for the most severe 
suicidal ideation. Suicidal behaviour is assessed by asking questions categorising behaviours 
into actual, aborted, and interrupted attempts; preparatory behaviour; and non-suicidal self-
injurious behaviour. 
If any item(s) on the C-SSRS are answered “yes”, the primary investigator or physician 
investigator must review the patient’s responses in order to (a) at screening and day-1 
determine the patient’s study eligibility and potential need for referral to a mental health 
professional, and (b) during the study evaluate the patient’s need for appropriate medical 
management such as a referral to a mental health professional.
A significant risk of suicide is defined as a “yes” in answer to (a) questions 4 or 5 on the suicidal 
ideation section; or (b) any questions on any item in the suicidal behaviour section. This must 

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The mDESS will be performed at each visit during the Screening Period (V1b onwards) and at 
Baseline in the subset of participants who are withdrawing from prohibited medication/s during 
the Screening Period.
Other Assessment Instruments 
8.3.1
Mini International Neuropsychiatric Interview, Version 7.0.2
The MINI was designed as a brief structured interview for the major Axis I psychiatric 
disorders in DSM-5 and International Classification of Diseases-10. Validation and reliability 
studies have been done comparing the MINI to the Structured Clinical Interview for DSM-5 
Patient Edition and the Composite International Diagnostic Interview (a structured interview 
developed by the World Health Organisation). Version 7.0.2 of the MINI will be used for this 
study. The results of these studies show that the MINI has similar reliability and validity 
properties, but can be administered in a much shorter period (mean 18.7 ± 11.6 min, median 
15 min) than the above referenced instruments. It can be used by clinicians after a brief training 
session.27
At screening, the presence of inclusionary and lack of exclusionary psychiatric diagnoses will 
be confirmed by use of the MINI 7.0.2.27
8.3.2
McLean Screening Instrument for Borderline Personality Disorder 
The MSI-BPD is a commonly used measure to assess for BPD. The scale consists of 10 items 
based on the DSM-5 BPD criteria; the first 8 items represent the first eight criteria in the 
DSM-5 for BPD diagnosis, while the last two questions assess the paranoia and dissociation 
criteria for BPD. Scores for the MSI-BPD range from 0 to 10, with each item rated as ͆1͇
if present and ͆0͇ if absent. A score of 7 or higher indicates a likelihood for the participant 
to meet criteria for BPD. The MSI-BPD will be collected at Screening only and participants 
positive for BPD will be subject to clinical confirmation of diagnosis by the study clinician 
and Medical Monitor. 
8.3.3
Life Event Checklist for DSM-5
LEC-5 is a self-report measure designed to screen for potentially traumatic events in a 
respondent's lifetime. The LEC-5 assesses exposure to 16 events known to potentially result in 
PTSD or distress and includes one additional item assessing any other extraordinarily stressful 
event not captured in the first 16 items. For each item in the list the participant has the option 
to reply, “happened to me”, “witnessed it”, “learned about it”, “part of my job”, “not sure”, 
“doesn’t apply”. The LEC-5 will be administered at screening together with the PCL-5.22
8.3.4
Childhood Trauma Questionnaire
The CTQ is a 28-item self-report measure validated to screen for history of childhood abuse 
and the meaning given to the abuse by the participant. It consists of 5 subscales measuring, 
physical abuse, sexual abuse, emotional abuse, physical neglect, and emotional neglect. The 
CTQ will be used at screening to exclude participants with childhood trauma.23

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8.3.5 
Semi-structured PTSD management interview  
Participants will be asked at baseline about their PTSD symptoms and feelings at the time of 
diagnosis and the type of treatments and support offered to them before joining the study.  
8.3.6 
Semi-structured qualitative interview  
Participants will be asked their overall opinion of their experience with COMP360 therapy, if 
they consider a single dose enough, the impact of the experience on their lives and any 
feedback on the study design. This will occur at day 2 and week 12. 
 
8.3.7 
Five Dimensional Altered States of Consciousness Questionnaire 
The 5D-ASC measures the acute drug effects using 5 primary dimensions and respective 
subdimensions to assess alterations in mood, perception, and experience of self in relation to 
environment and thought disorder. The 5 dimensions include oceanic boundlessness, anxious 
ego dissolution, visionary restructuralization, auditory alterations, and reduction of 
vigilance.24,25 This will be administered immediately after the psilocybin session on day of 
COMP360 administration.  
8.3.8 
Emotional Breakthrough Inventory  
The EBI is an eight-item brief measure intended to index the degree to which an individual 
experiences their emotion during the study drug administration session. Each of the items is a 
VAS, with units from 0 to 100. A total score can be derived by averaging individual item 
responses26.  
8.3.9 
Measure Health app  
If the participant opts to participate in the Measure Health portion of the study, the app will be 
activated on the participant’s mobile phone at the screening visit; it will be deactivated at the 
EOS. Participants who do not consent to the app installation, or do not have a smart phone, 
will not be excluded from the study.  
Mobile data collection: The Measure Health app will collect data from the participant’s smart 
phone and periodically send these data back to the HealthRhythms secure database. The 
participant will not need to do anything to collect these, except use their phone as they normally 
do. The data collected from the participant’s phone will include: 
x Activity data based on CoreMotion on iOS and the Activity Transition API on Android. 
x Location information from the Location API on both iOS and Android, which uses GPS 
and/or cell tower location information. 
x Device display status from Springboard on iOS and display on/off broadcast events on 
Android. These data are used to approximate when a user is actively using their phone. 

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x
Pedometer data (“steps”) based on CoreMotion on iOS and Google Fit on Android.The 
app may also maintain a list of target words and the participant’s use-frequency of these 
words. These words will be completely stripped from their context, thus preventing the 
content of any particular message from being deciphered.
No personally identifiable information is captured, and all captured data are encrypted on the 
smartphone before upload to Measure Health cloud storage servers, and the data remain 
encrypted in transit and at rest.
8.3.10
Biomarkers measurements
If the participant opts to participate in this portion of the study, additional blood samples will 
be drawn. Participants who do not consent to blood withdrawal for biomarkers will not be 
excluded from the study, and clinical laboratory tests will still be run for safety purposes.
Blood samples to measure biomarkers levels will be collected at baseline, week 4, and week 
12 after COMP360 administration. Up to 100mL of blood will be collected at each time 
point: five X 10ml EDTA tubes, one X 8.5ml serum tube, two X 2.5ml RNA PAXGene tube, 
and two X 8.5ml DNA PAXGene tube will be collected.
In addition to clinical laboratory measurements, the biomarkers measured will include
biomarkers related to stress and inflammation such as plasma or serum cortisol, oxytocin, 
ACTH, catecholamines, BDNF, NPY, and cytokines; telomere length and telomerase activity; 
and the expression levels of stress-relevant mRNAs through transcriptomics and candidate 
gene analyses.
In addition, aliquots of the samples will be bio-banked for future studies, such as for genome-
wide methylation, genome-wide expression, genotyping/GWAS (psych chip).
8.3.11
Magnetic Resonance Imaging 
If the participant opts to participate in this portion of the study, brain imaging via MRI will be 
performed at baseline and week 4. To reduce participant burden at baseline visit, the baseline 
MRI can be carried out  7 days prior to the baseline visit. The activity of brain regions will be 
monitored during the performance of an emotional go/no-go task. Participants who do not 
consent to the MRI scan will not be excluded from the study.
Protocol Deviations
All protocol deviations will be assessed and documented on a case-by-case basis before the 
database lock.

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To prepare for the drug experience, the participant will take the IMP and lie down in a room 
with dim lights and a standard playlist of relaxing music playing quietly. Two trained therapists
will be present with the participant at all times. 
The effects of COMP360 usually start about 20 to 30 min after administration, become most 
intense in the first 90 to 120 min, and gradually subside after 5 to 6 h. The participants will be 
asked to remain in the room for the duration of the session regardless of the intensity of the 
effects, preferably lying down. A light meal and fruit will be available for the participant. 
About 5 to 6 h after dosing, a trained therapist will discuss the study drug administration 
experience with the participant. The participant is to be discharged 6 to 8 h post-dosing when, 
in the opinion of the investigator, the acute effects of COMP360 are resolved. The participant 
will be accompanied home. The site is to be notified that they have returned home safely, and 
in the absence of receiving a phone call, site staff will directly contact the participant.
More details on preparation, administration, and integration sessions are available in the 
Therapist Manual. 
Accountability
The investigator must keep an accurate account of the number of IMP units delivered to the 
site, administered to participants, and returned to COMPASS or its designee during and at the 
completion of the study. The IMP must be administered to participants only by an appropriately 
qualified person. The IMP is to be used in accordance with the protocol by participants who 
are under the direct supervision of the investigator. Investigators should maintain records that 
document adequately that the participants were administered the IMP dose specified by the 
protocol and reconcile all IMPs received at the site before final disposition. At the end of the 
study, or as directed, all IMP, including unused, partially used, and empty containers, will be 
returned to the sponsor or its designee.
Compliance
Administration of the IMP will be supervised by study personnel to ensure compliance.

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10 CONCOMITANT THERAPY
All prescription and non-prescription medications (eg over-the-counter drugs and herbal 
supplements) that participants report taking during the 30 days prior to screening will be 
assessed and recorded at that visit. For each medication, documentation should list the trade or 
generic name, the total daily dose including units (or the dose, units and scheduled and actual 
frequency of administration if the medication is not taken daily), the route of administration, 
and the reason for use. 
Concomitant medication refers to all drugs and therapies used from the time the ICF was signed 
through the end of study participation. 
Changes, additions, or discontinuations to medications will be assessed and recorded in the 
eCRF during each study visit. All as-needed (pro re nata, PRN) prescriptions should be 
converted to reflect actual number of pills or dose taken per day. 
Permissible Medications
All concurrent non-serotonergic medications are allowed.
Medications for the management of concurrent anxiety and insomnia, or nonpsychiatric 
medications that have a potential psychotropic effect are permitted with the following 
limitations. From the initial screening visit through final study visit (EOS), participants are 
permitted to remain on the same regular dose regimen of benzodiazepines they were already 
on in order to avoid withdrawal symptoms. Participants who were not taking benzodiazepines 
before screening may take up to 2 mg of lorazepam equivalents per day for anxiety emerging 
during the withdrawal of antidepressant and antipsychotic medications. Benzodiazepines may 
not be taken within 8 hours before COMP360 administration. Hypnotics such as zopiclone, 
eszopiclone or zolpidem are allowed for insomnia. Prescription and non-prescription 
medications with psychoactive properties that are used as needed for nonpsychiatric conditions 
(eg pseudoephedrine for allergies or cold symptoms;) can be used daily but not within 12 hours 
before dosing. Documentation of the use of adjunctive anxiolytics, hypnotics or medication 
with potential psychotropic properties (including over-the-counter preparations) will be 
obtained at each clinic visit. Medications prescribed for ADHD, including all psychostimulants 
for ADHD (ATC code N06B), all psychostimulants in combination with psycholeptics (ATC 
code N06BC), clonidine, guanfacine, and atomoxetine are permitted. 
Therapy considered necessary for the participant’s welfare may be given at the discretion of 
the study clinician.
Definition of Women of Childbearing Potential and/or Acceptable Contraceptive 
Methods
A woman is considered of childbearing potential (eg fertile) following menarche and until 
becoming postmenopausal unless permanently sterilised (eg participant had hysterectomy, 
bilateral salpingectomy, or bilateral oophorectomy). 

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A woman who is not of childbearing potential is considered to be postmenopausal after at least 
12 months without menstruation.  
The following methods of contraception, if used properly and used for the duration of the study, 
are generally considered highly effective:  
o Combined oestrogen- and progestogen-containing hormonal contraception associated 
with inhibition of ovulation: 
 Oral 
 Intravaginal 
 Transdermal 
o Progestogen-only hormonal contraception associated with inhibition of ovulation: 
 Oral  
 Injectable 
 Implantable 
o Intrauterine device 
o Intrauterine hormone-releasing system 
o Bilateral tubal occlusion 
o Vasectomised partner 
o Sexual abstinence is considered a highly effective method only in case of refraining 
from heterosexual intercourse during the entire period of the clinical trial and when in 
line with the preferred and usual lifestyle of the subject 
Periodic abstinence (eg calendar, symptothermal, or post-ovulation methods, and tubal 
ligation/occlusion) is not an acceptable form of contraception for this study.   
These methods of contraception also apply to partners of male participants. 
The investigator and each participant will determine the appropriate method of contraception 
for the participant during the participation in the study. This will be documented at screening. 
If a participant or the partner of a male participant becomes pregnant during the study, the 
investigator will notify the PI, study sponsor and COMPASS immediately after the pregnancy 
is confirmed according to Section 14.5.  

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Prohibited Medications
Participants are to be discontinued from antidepressant and/or antipsychotic medications at 
least two weeks prior to baseline visit. These medications include the following two classes of 
the Anatomical Therapeutic Chemical (ATC) Classification System: - NO5A Antipsychotics 
& NO6A Antidepressants. Methylphenidate is also excluded. Participants should also 
discontinue prazosin one week before COMP360 administration session. 
The medical monitor should be contacted if there is any question that a used medication is 
thought to be in one of these classes. These medications are not to be reintroduced to the 
participant until after week 4. Participants who require concomitant medication(s) specifically 
for the treatment of PTSD at any time through the duration of the study will be assessed for 
reasons of resuming their medications and followed until 12 weeks post COMP360 
administration. Participants can resume taking prazosin the day after administration session, if 
necessary. The study clinician should initiate treatment of symptoms of PTSD as deemed 
appropriate and may change the venue of therapy (eg outpatient to inpatient) if deemed 
clinically necessary. The intervention may be a combination of somatic (eg approved 
antidepressant medication) and non-somatic (various forms psychotherapy, eg TF- CBT) 
whose therapeutic intention is remediation of PTSD symptoms. Because the anticipated half-
life of COMP360 is approximately 3 h, and only 1 administration of test product is permitted, 
no known issues regarding pharmacokinetics or pharmacodynamic interactions are envisioned 
within approximately 7 days of product administration.
Rescue Medication
Rescue medications may be used during and after the administration session. 
The decision to medicate a participant will depend on whether the responsible physician judges 
that they are capable of maintaining the safety of the participant and others without medical 
intervention.
x
Benzodiazepine anxiolytics are the pharmacological intervention of choice in case of acute 
psychological distress (eg medications such as lorazepam or alprazolam that have a rapid 
onset, a short time until peak plasma concentration, and a short duration of therapeutic 
action; the oral route is preferable because IV injection procedures may further exacerbate 
the participant’s anxiety) 
x
Antipsychotic medications (eg risperidone) should be available in the event that an 
adverse reaction escalates to unmanageable psychosis. 
In case of the development of acute anxiety or psychotic symptoms requiring pharmacological 
intervention, the participant will be managed appropriately. The participant may be discharged 
from the clinic when, in the opinion of investigator, the condition has stabilised. The participant 
will be accompanied home. The site is to be notified by the participant that they have returned 
home safely, and in the absence of receiving a phone call site staff will directly contact the 
participant. 

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Information for how to manage participants during difficult psychological states are detailed 
in the Therapist Manual.  
  

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11 ADVERSE EVENTS
Throughout the course of the study, all AEs will be monitored and recorded in the eCRF, 
including the AE’s description, start and end date, seriousness, severity, action taken, and 
relationship to the IMP. If AEs occur, the first concern will be the safety of the study 
participants. 
Per ICH E2A: An AE is any untoward medical occurrence in a participant or clinical 
investigation participant administered a pharmaceutical product and which does not necessarily 
have to have a causal relationship with this treatment. An AE can therefore be any unfavourable 
and unintended sign (including an abnormal laboratory finding, for example), symptom, or 
disease temporally associated with the use of a medicinal product, whether considered related 
to the medicinal product. 
Medical interventions such as surgeries, diagnostic procedures, and therapeutic procedures are 
not AEs, but the action taken to treat the medical condition. They should be recorded as 
treatment of the AEs. 
The investigator will promptly notify COMPASS or Worldwide Clinical Trials of all SAEs 
and nonserious AEs occurring during the clinical trial so that legal obligations and ethical 
responsibilities towards the safety of participants and the safety of the product under clinical 
investigation are met. 
COMPASS or Worldwide Clinical Trials has a legal responsibility to notify both the local 
regulatory authority and other regulatory agencies about the safety of a product under clinical 
investigation. COMPASS or Worldwide Clinical Trials will comply with country-specific 
regulatory requirements relating to safety reporting to the regulatory authority, Institutional 
Review Board (IRB)/Independent Ethics Committee (IEC), and investigators. These will be 
detailed in the safety plan. 
Documenting Adverse Events
AEs occurring from when the participant signs the ICF until the last study event will be 
recorded. Any AEs occurring before the start of treatment (eg before the dose of the IMP on 
day 1) will be recorded as pre-treatment AEs. Also, the sign, symptom, or disease present 
before starting the treatment period are only considered AEs if they worsen after starting the 
treatment period. Investigators should document all significant illnesses that the participant has 
experienced within 3 months of the screening and up to the day of inclusion.  Illnesses first 
occurring or detected during the study and/or worsening of a concomitant illness during the 
study are to be documented as AEs.
All clinical laboratory results, vital signs, and ECG results or findings should be appraised by 
the investigator to determine their clinical significance. Isolated abnormal clinical laboratory 
test results, vital sign findings, or ECG findings (eg not part of a reported diagnosis) should be 
reported as AEs if they are symptomatic, lead to IMP discontinuation/study withdrawal, require 
corrective treatment, or constitute an AE in the investigator’s clinical judgment.

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At each time point, the investigator will determine whether any AEs have occurred by 
evaluating the participant. AEs may be directly observed, reported spontaneously by the 
participant or by questioning the participant at each time point. Participants should be 
questioned in a general way, without asking about the occurrence of any specific symptoms. 
The investigator must assess all AEs to determine intensity, causality and seriousness, in 
accordance with the definitions in Sections 11.2, 11.3, and 12.1, respectively. The 
investigator’s assessment must be clearly documented in the study site’s source documentation 
with the investigator’s signature. 
Always report the diagnosis as the AE or SAE term. When a diagnosis is unavailable, report 
the primary sign or symptom as the AE or SAE term with additional details included in the 
narrative until the diagnosis becomes available. If the signs and symptoms are distinct and do 
not suggest a common diagnosis, report them as individual entries of AE or SAE.
The investigator should report all AEs on the AE page(s) of the eCRF and source documents, 
regardless of seriousness, severity, and causality. Whenever possible, an AE will be reported 
using a diagnostic term, (eg “common cold” or “upper respiratory infection” rather than 
“runny nose, cough, mild fever”) and should be described with the attributes described in 
Sections 11.2 and 11.3. 
Assessment of Intensity
Each AE will be classified according to the following criteria:
Mild:
The AE does not interfere in a significant manner with the 
participant’s normal level of functioning.
Moderate:
The AE produces some impairment of functioning but is not 
hazardous to the participant’s health.
Severe:
The AE produces significant impairment of functioning or 
incapacitation and is a definite hazard to the participant’s health.
Severity versus Seriousness: Severity is used to describe the intensity of a specific event while 
the event itself, however, may be of relatively minor medical significance (such as severe 
headache). This is not the same as "seriousness," which is based on participant/event outcome 
at the time of the event.
When changes in the intensity of an AE occur more frequently than once a day, the maximum 
intensity for the experience should be noted. If the intensity category changes over several 
days, those changes should be recorded separately (with distinct onset dates).
Assessment of Causality
Each AE will be assessed as to its relationship to the IMP, based on the following criteria. 
Although the attribution by the investigator will be collected for reported events, for analytic 
purposes a temporal association with the use of the IMP will be assumed sufficient for at least 

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plausible association. All noxious and unintended responses to the IMP related to the dose 
should be reported as Adverse Drug Reactions (ADR).
Not related:
No causal relationship exists between the IMP and the AE, but an 
obvious alternative cause exists, eg the participant’s underlying 
medical condition or concomitant therapy.
Possibly related:
A connection with the administration of the IMP appears unlikely 
but cannot be ruled out with certainty. An AE may be considered 
possibly related if or when it meets 2 of the following criteria: (1) it 
follows a reasonable temporal sequence from administration of the 
IMP; (2) it could not readily have been produced by the participant’s 
clinical state, environmental or toxic factors, or other modes of 
therapy administered to the participant; or (3) it follows a known 
pattern of response to the IMP.
Related:
There is a reasonable/plausible possibility that the AE may have 
been caused by the IMP.
When assessing the relationship to the IMP, the following criteria will be considered:
o
Known class effect
o
Biological plausibility
o
Lack of alternative explanation—concomitant drug or disease
Action Taken Regarding Investigational Medicinal Product
Dose modifications of IMP (eg dose not changed, drug withdrawn, drug interrupted, or dose 
increased) are not applicable as this is a single dose study. 
o
Not Applicable: Participant died, study treatment had been completed prior to 
reaction/event, or reaction/event occurred prior to start of treatment
Other Action Taken for Event
Other possible actions that can be taken for event are the following:
x
None (eg no treatment was required)
x
Medication required (eg prescription and/or OTC medication was required to treat 
the AE)
x
Hospitalisation or prolongation of hospitalisation required (eg hospitalisation was 
required or prolonged because of the AE, whether medication was required)
x
Other

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Adverse Event Outcome
The outcome of AEs can be defined as one of the following:
x
Recovered/Resolved (eg the participant fully recovered from the AE with no
residual effect observed)
x
Recovering/Resolving (eg the AE improved but has not fully resolved)
x
Not Recovered/Not Resolved (eg the AE itself is still present and observable)
x
Recovered/Resolved with Sequelae (eg the residual effects of the AE are still 
present and observable, including sequelae/residual effects)
x
Fatal (eg ‘fatal’ should be used when death is a direct outcome of the AE)
x
Unknown
Clinical Laboratory Changes
Clinically significant abnormalities in a laboratory value that is new in onset or which has 
worsened in severity or frequency from the baseline condition and meets one of the following 
criteria will be recorded and reported as an AE:
o
Requires therapeutic intervention or diagnostic tests
o
Has accompanying or inducing symptoms or signs
o
Is judged by the investigator as clinically significant
Combined elevations of aminotransferases and bilirubin, either serious or nonserious, and 
whether causally related, meeting the criteria of a potential Hy’s Law case (total bilirubin level 
 3 × upper limit of normal [ULN] with simultaneous ALT or AST  3 × ULN) should always 
be reported to the sponsor as soon as possible following the procedures outlined in Section 10.2
for SAE reporting, with the investigator’s assessment of seriousness, causality, and a detailed 
narrative.
Overdose
Any instance of overdose (suspected or confirmed) must be communicated to the CRO, within 
24 hours and be fully documented as an AE or SAE if it meets the SAE criteria. Details of any 
signs or symptoms and their management should be recorded including details of any 
antidote(s) administered.
Adverse Events of Special Interest
An adverse event of special interest (AESI) is an AE (serious or nonserious) of scientific and 
medical concern specific to the study drug, for which ongoing monitoring and immediate 

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notification by the investigator to COMPASS and the CRO is required. Such AEs may require 
further investigation to characterise and understand them.  
The following events will be reported as AESI: 
AESI term 
MedDRA Preferred Terms  
Euphoric mood 
Euphoric mood 
Dissociative disorder 
Dissociative disorder; Dissociative identity 
disorder; Dissociative amnesia; Dissociation; 
Depersonalisation/derealisation disorder 
Hallucination 
Hallucination; Hallucination, auditory; 
Hallucination, synaesthetic; Hallucination, 
tactile; Hallucination, visual; Hallucination, 
olfactory; Hallucinations, mixed; Somatic 
hallucination 
Psychotic disorder 
Psychotic disorder; Psychotic behaviour; Acute 
psychosis; Hysterical psychosis; Reactive 
psychosis; Substance-induced psychotic 
disorder; Brief psychotic disorder with marked 
stressors; Brief psychotic disorder without 
marked stressors; Transient psychosis 
Cognitive disorder 
Cognitive disorder 
Disturbance in attention 
Disturbance in attention 
Mood altered 
Mood altered; Depressed mood; Affect lability; 
Fluctuating mood symptoms 
Psychomotor skills impaired 
Psychomotor skills impaired 
Inappropriate affect 
Inappropriate affect 
Overdose 
Overdose 
Intentional product misuse 
Intentional product misuse 
Suicidal behaviour 
Suicidal behaviour, intentional self-injury, 
completed suicide, suicide attempt  
Suicidal ideation 
Suicidal ideation, depression suicidal 
The investigator must report to COMPASS and the CRO all the above events within 24 hours 
of learning about the event regardless of relationship to study drug. 
The report should include the following minimum information: 
o Participant number 
o Event 
o Date/time of onset 
o Duration of the event 
o Dose of drug taken 
o Severity 
o Outcome  

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Adverse Event Follow-up
All SAEs related to the IMP will be followed until resolved or stable and the outcome 
documented. All AESIs will be followed up until the end of the study. 
If the investigator detects an AE in a study participant after the last scheduled follow-up visit 
and considers the event possibly related or related to prior study treatment, the investigator 
should report it to COMPASS and the CRO.

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12 SERIOUS ADVERSE EVENTS
Definition of Serious Adverse Event
An SAE is any event that meets any of the following criteria:
o
Death
o
Life-threatening
o
Inpatient hospitalisation or prolongation of existing hospitalisation
o
Persistent or significant disability/incapacity
o
Congenital anomaly/birth defect in the offspring of a participant who received 
psilocybin.
o
Other: Important medical events that may not result in death, be life-threatening, or 
require hospitalisation, may be considered an SAE when, based upon appropriate 
medical judgment, they may jeopardise the participant and may require medical or 
surgical intervention to prevent one of the outcomes listed in this definition. Examples 
of such events are:

Intensive treatment in an emergency room or at home for allergic bronchospasm

Blood dyscrasias or convulsions that do not result in inpatient hospitalisation

Development of drug dependency or drug abuse
Definition of Terms
Life-threatening: An AE is life-threatening if the participant was at immediate risk of death 
from the event as it occurred; eg it does not include a reaction that if it had occurred in a more 
serious form might have caused death. For example, drug-induced hepatitis that resolved 
without evidence of hepatic failure would not be considered life-threatening even though drug-
induced hepatitis can be fatal.
Hospitalisation: AEs requiring hospitalisation should be considered SAEs. Hospitalisation for 
elective surgery or routine clinical procedures that are not the result of AEs (eg elective surgery 
for a pre-existing condition that has not worsened) need not be considered AEs or SAEs. If 
anything untoward is reported during the procedure, that occurrence must be reported as an 
AE, either 'serious' or 'nonserious' according to the usual criteria.
In general, hospitalisation signifies that the participant has been detained (usually involving at 
least one an overnight stay) at the hospital or emergency ward for observation and/or treatment 
that would not have been appropriate in the physician's office or outpatient setting. When in 
doubt as to whether 'hospitalisation' occurred or was necessary, the AE should be considered 
serious.

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For deaths, the underlying or immediate cause of death should always be reported as an SAE.
Any serious, untoward event that may occur subsequent to the reporting period that the 
investigator assesses as related to IMP should also be reported and managed as an SAE.
The investigator should follow participants with AEs until the event has resolved or the 
condition has stabilised. In case of unresolved AEs, including significant abnormal clinical 
laboratory values at the end of study assessment, these events will be followed until resolution 
or until they become clinically not relevant.
Disability/incapacitating: An AE is incapacitating or disabling if the experience results in a 
substantial and/or permanent disruption of the participant's ability to carry out normal life 
functions.
Reporting Serious Adverse Events
Each AE will be assessed to determine whether it meets seriousness criteria (Section 12.1). If 
the AE is considered serious, the investigator should report this event to the CRO, and to the 
IRB/IEC according to its standard operating procedures.
If the investigator detects an SAE in a study participant after the last scheduled follow-up visit, 
and considers the SAE related or possibly related to this study’s IMP administration, the 
investigator should report it to the CRO.
The investigator must report to the sponsor all SAEs on the eCRF page within 24 hours of 
learning about the event regardless of relationship to IMP. 
All information about SAEs will be collected and reported via the SAE form and sent by e-
mail message or facsimile (contact information will be contained in the investigator site file). 
The investigator should send the initial report within 24 h of becoming aware of the SAE. At 
minimum, the initial report should include the following information: 
o
Event and brief description of the SAE (including diagnosis or signs/symptoms)
o
Study code
o
Participant identification number, initials, gender, and date of birth
o
IMP
o
Reporter name and contact information
If the site experiences a temporary disruption of the eCRF system, a back-up paper SAE Report 
Form will be available for site staff to complete. 
• Site staff will complete the paper SAE report form and e-mail it within 24 h to the 
following address: 

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• In cases where the email system is unavailable, site staff will send the SAE by fax to: 
 and 
 
If notification is made via email or fax, site staff must enter the SAE information into the eCRF 
system as soon as the system becomes available. Should a back-up SAE form be used, the 
original SAE form should be kept at the study site.  
If the SAE has not resolved at the time the investigator submits an initial SAE report, the 
investigator must provide a follow-up report as soon as the event resolves (or upon receipt of 
significant information if the event is still ongoing). Additional follow-up information must be 
reported in the eCRF within 24 h of awareness following investigator (or site) awareness of the 
information. The investigator should not delay reporting an SAE in order to obtain additional 
information. Additional information, when available, should be reported per the reporting 
procedures described above.  
All SAEs shall be followed until resolution, until the condition stabilises, or until the participant 
is lost to follow-up, or otherwise explained. Once the SAE is resolved, the corresponding AE 
eCRF page shall be updated. Additionally, any relevant laboratory test reports, consultation 
reports from other health care professionals, discharge summaries, or other information that 
has been gathered about the event shall be transmitted to the sponsor.  
In the case of a “minimum report” (one that solely comprises the information bulleted above), 
a more detailed follow-up report should be sent as soon as more information becomes available 
but no later than 7 calendar days after the date of the initial report. Each SAE should be 
followed up until resolution or stabilisation and for reported deaths, the investigator should 
supply the CRO and the IRB/IEC with any additional requested information (eg, autopsy 
reports and terminal medical reports).  
The original SAE form should be kept at the study site. The sponsor or its representative will 
be responsible for determining and in turn, reporting SAEs to regulatory authorities according 
to the applicable regulatory requirements.  
All SAEs will be followed until resolved or stable and the outcome documented on the eCRF.  
Investigator safety reports will be prepared for suspected unexpected serious adverse reactions 
(those not listed in the IB) according to local regulatory requirements and COMPASS/the CRO 
policy and are forwarded to investigators as necessary.  
An investigator who receives an investigator safety report describing an SAE(s) or other 
specific safety information (eg summary or listing of SAEs) from COMPASS or the CRO will 
file it with the IB and will notify the IRB/IEC, if appropriate according to local requirements. 
 

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13 STATISTICS
Hypotheses and Treatment Comparisons
There are no formal hypotheses being tested in this study.
Sample Size Considerations
The sample size is not based on a formal statistical evaluation but is considered to be adequate 
to meet the objectives of the study.
Analysis Sets
Analysis Population
Definition
Safety Analysis Set
All participants who receive study drug
Full Analysis Set (FAS)
All participants in the Safety Analysis Set who have at least one
post-baseline efficacy assessment
The Safety Analysis Set will be used for all safety-related evaluations and study population-
related evaluations. The FAS will be used for all efficacy-related evaluations.
General Considerations
A detailed Statistical Analysis Plan (SAP) will be finalised and signed before database lock. 
Any deviations from the methods described below will be included in the SAP and considered 
final, which will be included in the Clinical Study Report (CSR).
All TFLs will be created using SAS® version 9.4 or higher.
Unless otherwise specified, “baseline” is defined as the last observed value of the parameter of 
interest prior to dosing. For numerical variables, change from baseline will be calculated as the 
difference between the value of interest and the corresponding baseline value. 
Continuous data will be summarised descriptively using N (number of participants), n (number 
of observations), mean, standard deviation (SD), median, minimum and maximum. Categorical 
data will be summarised using frequency counts and percentages. Confidence intervals for 
selected endpoints will also be displayed.
All individual participant data will be listed.
Data Handling
Procedures for the handling of any missing, unused or spurious data will be described in the 
SAP.

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13.5.1 
Analysis of Efficacy 
Since this is a single treatment open-label study, no statistical testing will be performed. 
The FAS will be used for all efficacy-related endpoints, if the two sets are not identical. For 
each of the secondary (CAPS-5, PCL-5, SDS and EQ-5D-5L (including EQ VAS)) and some 
exploratory endpoints (PACT, RAS) measuring changes from baseline, summary statistics will 
be provided. In addition, 95% confidence intervals for changes from baseline as well as for 
proportions of responders and remitters based on the CAPS-5 will be provided. Graphical 
displays will also be created for a subset of the efficacy endpoints to visualise their profile over 
time. 
Analysis of all exploratory endpoints will be further detailed in the SAP. 
13.5.2 
Analysis of Safety 
13.5.2.1 
Adverse Events 
AEs will be coded by System Organ Class (SOC) and Preferred Term (PT) using the Medical 
Dictionary for Regulatory Activities (MedDRA) classification.  
A TEAE is defined as any AE that has an onset on or after taking study drug, or any pre-existing 
condition that has worsened on or after taking study drug. 
The frequency and incidence of TEAEs will be summarised by SOC and PT. Summaries will 
also include, but not limited to, relationship to study drug and maximum severity. The summary 
will be sorted by International Agreed Order for SOC and alphabetical order for Preferred 
Term. 
For each of the summaries produced at the participant level, multiple occurrences of the same 
event within a participant will be counted once in the summaries by SOC and Preferred Term; 
multiple occurrences of the same event within a participant will be counted once in the 
maximum severity category (severe > moderate > mild) and/or maximum drug relationship 
category (reasonable possibility/no reasonable possibility). If severity or relationship is found 
to be missing, the most severe occurrence will be imputed for that particular summary. 
AESIs will also be presented using the same logic as for general AE summary tables, including 
patient incidence and event counts. 
These summaries will also present the number of events that occurred, so multiple occurrences 
of the same event within a participant will all be accounted for in the maximum intensity 
category and maximum relationship category they were classed as. 
13.5.2.2 
Electrocardiogram Data 
ECG data and changes from baseline/screening will be summarised by visit. Frequency 
tabulations of the abnormalities will be provided, as well a summary using the ICH E14 
Guideline: The Clinical Evaluation of QT/QTc Interval Prolongation and Proarrhythmic 
Potential for Non-Antiarrhythmic Drugs. ECG variables to be analysed will include heart rate 

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(bpm), PR interval (ms), QRS interval (ms), QT interval (ms), and corrected QT interval using 
the following correction methods: QT corrected according to Bazett’s formula [QTcB (ms)] 
and QT corrected according to Fridericia’s formula [QTcF (ms)]. 
13.5.2.3 
Vital Signs 
Vital signs data and changes from baseline/screening will be summarised by visit. Frequency 
tabulations of the abnormalities will be provided. Vital sign variables to be analysed will 
include blood pressure [systolic (mmHg) and diastolic (mmHg)], body temperature (oC), and 
pulse rate (beats/min). The percentage of participants with values outside clinically important 
limits will be summarised, using the following limits: 
 
Vital sign 
Lower Limit 
Upper Limit 
Systolic blood pressure 
(mmHg) 
90 mmHg 
160 mmHg 
Diastolic blood pressure 
(mmHg) 
50 mmHg 
100 mmHg 
Pulse rate (bpm) 
50 bpm 
100 bpm 
Body temperature (degrees 
Celsius) 
- 
37.5 ႏ 
 
13.5.2.4 
Laboratory Data 
Observed values and changes from baseline for haematology and blood chemistry parameters 
will be summarised by visit. All presentations will be based on the International System of 
Units. The frequency of laboratory abnormalities will be tabulated.  
By-participant data listings will flag laboratory values that are outside normal reference ranges 
or markedly abnormal findings. 
13.5.2.5 
Columbia-Suicide Severity Rating Scale  
C-SSRS data, including item scores, suicidal ideation, and suicidal behaviour, will be 
summarised by visit. 
13.5.2.6 
mDESS 
Data listings will present mDESS data at the Screening and Baseline visits. 
13.5.2.7 
BPRS+ 
Data listings will present BPRS+ data by visit. 

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13.5.3
Participant Disposition, Demographic and Baseline Characteristics
Participant disposition, including number of screen failures, participants in each analysis set, 
completers and early discontinuation as well as reason, will be summarised.
Demographic data and baseline characteristics, including age at screening, gender, race, 
ethnicity, height, body weight, BMI and duration of PTSD will be summarised.
13.5.4
Medical History
Medical history will be coded using MedDRA latest version and summarised and listed for all 
participants.
13.5.5
Prior and Concomitant Medication
Prior and concomitant medications will be summarised and listed.
Prior medication refers to any medication that was stopped prior to the start of taking study 
drug/ taken during the 30-day period before signing the ICF. Concomitant medication refers to 
the use of any ongoing medication use at the time of the start of the study /all medications taken 
after the ICF has been signed.
Interim Analysis 
No interim analysis is planned for this study.

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14 ETHICS AND RESPONSIBILITIES
Good Clinical Practice
The study will be performed in accordance with this protocol, US investigational new drug 
(IND) regulations (21 Code of Federal Regulations [CFR] 312), ICH guidelines for Good 
Clinical Practice (GCP), the regulations on electronic records and electronic signature (21 CFR 
11), and the most recent guidelines of the Declaration of Helsinki (Section 21.2). These 
guidelines are on file at the CRO. 
The study will also be performed in accordance with any laws and regulations in force in the 
country in which the research is carried out. 
Data and Safety Monitoring Board
A Data and Safety Monitoring Board (DSMB) will periodically review and evaluate the 
accumulated study data for participant safety, study conduct and progress and when 
appropriate, efficacy. The DSMB will make recommendations concerning the continuation, 
modification or termination of the trial, always ensuring participant safety is paramount. As 
outlined in the DSMB charter, the DSMB can recommend modifying or stopping the study if 
the risks to participants appear to exceed the benefits by following the below guidance: 
x
Any participant who experiences increases in aspartate aminotransferase (AST) or 
alanine aminotransferase (ALT) 5-fold upper limit of normal (ULN), or 3-fold ULN 
with concomitant serum total bilirubin 2-fold the ULN and 35% direct, will be 
withdrawn from the study and will be followed until resolution of the abnormal 
laboratory values. 
x
Any participant who experiences clinically significant suicidal risk or risk of self-injury 
during study participation will be withdrawn from the study and followed until 
resolution.
Other stopping criteria will include:
x
A ‘serious’ adverse reaction in two participants, ie, an SAE that is considered at least 
possibly related to IMP administration.
x
If there is an unacceptable tolerability profile based on the nature, frequency and 
intensity of observed AEs and/or clinical safety monitoring in the opinion of the 
investigator.
x
If any of the above study stopping criteria are fulfilled, all dosing will be stopped 
immediately in all study participants. No further dosing will be permitted at a group or 
individual level. If the trial is halted due to safety concerns, or because the stopping 
criteria are fulfilled, the trial will only resume after Research Ethics Committee (REC) 
and regulatory authority approval via a substantial amendment.

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The composition, the frequency of the review, range of decisions permitted, and the methods 
for dissemination of information will be addressed in a separate charter. 
Institutional Review Board/ Independent Ethics Committee
Conduct of the study must be approved by an appropriately constituted IRB/ IEC. Approval 
is required for the study protocol, protocol amendments, ICFs, participant information sheets, 
and advertising materials.
Informed Consent
Written, informed consent will be obtained from all study participants. Participants should be 
informed that they may withdraw from the study at any time. They will receive all information 
that is required by local regulations and ICH guidelines. The Principal Investigator or a 
designated representative will provide the sponsor or its representative with a copy of the IRB 
approved ICF before the start of the study.
Exposure in Utero During Clinical Studies
Sponsor must be notified of any participant who becomes pregnant within 30 days of receiving 
the IMP. Reporting after the follow-up visit or ET is done voluntarily by the investigator. 
Sponsor must be notified of any male participant whose partner becomes pregnant within 30 
days of the participant receiving the IMP. Reporting after any follow-up visit or ET is done 
voluntarily by the investigator. 
Although pregnancy is not technically an AE, all pregnancies must be followed to conclusion 
to determine their outcome. This information is important for both drug safety and public health 
concerns. It is the responsibility of the investigator, or designee, to report any pregnancy in a 
participant or the partner of a male participant using the eCRF pregnancy within 24 h of 
becoming aware of the event. Exposure in Utero (EIU) Reporting form. Please contact your 
study monitor to receive the EIU Reporting form upon learning of a pregnancy. The 
investigator should make every effort to follow the participant until completion of the 
pregnancy and complete the EIU Reporting form eCRF with complete pregnancy outcome 
information, including normal delivery and induced abortion. The adverse pregnancy outcome, 
either serious or nonserious, should be reported in accordance with study procedures. If the 
outcome of the pregnancy meets the criteria for immediate classification as an SAE (ie post-
partum complications, spontaneous or induced abortion, stillbirth, neonatal death, or congenital 
anomaly, including that in an aborted foetus), the investigator should follow the procedures for 
reporting SAEs outlined in Section 12. In the event the eCRF system is unavailable, a back-up 
paper Pregnancy Reporting Form will be available for site staff to complete following the 
reporting guidelines as outlined in Section 12.2. 
For reports of pregnancy in the partner of a male participant within 30 days from receiving the 
IMP, the pregnancy eCRF page EIU form (or SAE form if associated with an adverse outcome) 
should be completed with the participant’s initials, and date of birth, and details regarding the 
partner of the male participant should be entered in the narrative section. 

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Records Management
By signing this protocol, the investigator grants permission to personnel from the sponsor, its 
representatives, and appropriate regulatory authorities, for on-site monitoring of all appropriate 
study documentation, paper and electronic, as well as on-site review of the procedures 
employed in eCRF generation, where clinically appropriate. 
Source Documentation
Note that a variety of original documents, data, and records will be considered as source 
documents in this trial. The eCRF itself is not to be used as a source document under any 
circumstances.
Study Files and Record Retention
The investigator must arrange for retention of study records at the site. The nature of the records 
and the duration of the retention period must meet the requirements of the relevant regulatory 
authority. In addition, because this is an international study, the retention period must meet the 
requirements of the most stringent authority. The investigator should take measures to prevent 
accidental or premature destruction of these documents.

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15 AUDITING AND MONITORING 
This study will be monitored for quality assurance at all stages of its development by the 
clinical research personnel employed by the sponsor or its representative. Monitoring will 
include personal visits and telephone communication to assure that the investigation is 
conducted according to the protocol, standard operating procedures, GCP guidelines, and 
applicable regulatory requirements. Quality control procedures will be applied to each stage of 
data handling to ensure that all data are reliable and have been processed correctly. On-site 
review of eCRFs will include a review of forms for completeness and clarity, and consistency 
with source documents available for each participant. 
The investigator and appropriate personnel will be periodically requested to attend 
meetings/workshops organised by the sponsor to assure acceptable protocol execution. The 
study may be audited by the sponsor or by regulatory authorities. If such an audit occurs, the 
investigator must agree to allow access to required participant records. By signing this protocol, 
the investigator grants permission to personnel from the sponsor, its representatives, and 
appropriate regulatory authorities, for on-site monitoring of all appropriate study 
documentation, as well as on-site review of the procedures employed in eCRF generation, 
where clinically appropriate. 
 

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16 AMENDMENTS 
Protocol modifications, except those intended to reduce immediate risk to study participants, 
may be made only by COMPASS. A protocol change intended to eliminate an apparent 
immediate hazard to participants may be implemented immediately, provided the IRB/IEC is 
notified within five days. 
Any permanent change to the protocol must be handled as a protocol amendment. The written 
amendment must be submitted to the IRB/IEC and the investigator must await approval before 
implementing the changes. COMPASS will submit protocol amendments to the appropriate 
regulatory authorities for approval.  
If in the judgment of the IRB/IEC, the investigator, and/or COMPASS the amendment to the 
protocol substantially changes the study design and/or increases the potential risk to the 
participant and/or has an impact on the participant's involvement as a study participant, the 
currently approved written ICF will require similar modification. In such cases, informed 
consent will be renewed for participants enrolled in the study before continued participation. 

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17 STUDY REPORT AND PUBLICATIONS 
COMPASS is responsible for preparing and providing the appropriate regulatory authorities 
with clinical study reports according to the applicable regulatory requirements. 
The publication policy of COMPASS is discussed in the investigator's Clinical Research 
Agreement. 

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18 STUDY DISCONTINUATION  
Both COMPASS and the Principal Investigator reserve the right to terminate the study at any 
time. Should this be necessary, COMPASS or a specified designee will inform the appropriate 
regulatory authorities of the termination of the study and the reasons for its termination, and 
the Principal Investigator will inform the IRB/IEC of the same. In terminating the study, 
COMPASS and the Principal Investigator will assure that adequate consideration is given to 
the protection of the participants’ interests.  

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19 CONFIDENTIALITY 
All information generated in this study is considered highly confidential and must not be 
disclosed to any person or entity not directly involved with the study unless prior written 
consent is gained from COMPASS. However, authorised regulatory officials, IRB/IEC 
personnel, COMPASS and its authorised representatives are allowed full access to the records.  
Identification of participants and CRFs shall be by initials, screening and treatment numbers 
only. If required, the participant's full name may be made known to an authorised regulatory 
agency or other authorised official.  

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20 REFERENCES 
 
1 
Krystal, J. H. et al. It Is Time to Address the Crisis in the Pharmacotherapy of 
Posttraumatic Stress Disorder: A Consensus Statement of the PTSD 
Psychopharmacology Working Group. Biol Psychiatry 82, e51-e59, 
doi:10.1016/j.biopsych.2017.03.007 (2017). 
2 
Compass Pathways Limited. Investigator’s Brochure: Psilocybin. 1-76 (London, 
2020). 
3 
(NICE), N. I. f. H. a. C. E. Post-traumatic stress disorder NICE guideline [NG116], 
2018). 
4 
(APA), T. A. P. A. Clinical Practice Guideline for the Treatment of Posttraumatic 
Stress Disorder (PTSD) in Adults, <> (2018). 
5 
Grinage, B. D. Diagnosis and Management of Post-traumatic Stress Disorder. 
American Family Physician 68, 2401-2408 (2021). 
6 
Brown, R. T. et al. in Clinical Pharmacokinetics Vol. 56   1543-1554 (Springer 
International Publishing, 2017). 
7 
Vollenweider, F. X., Vollenweider-Scherpenhuyzen, M. F. I., Bäbler, A., Vogel, H. & 
Hell, D. Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 
agonist action. NeuroReport 9, 3897-3902, doi:10.1097/00001756-199812010-00024 
(1998). 
8 
Preller, K. H. et al. The Fabric of Meaning and Subjective Effects in LSD-Induced 
States Depend on Serotonin 2A Receptor Activation. Curr Biol 27, 451-457, 
doi:10.1016/j.cub.2016.12.030 (2017). 
9 
Carhart-Harris, R. L. et al. Psilocybin with psychological support for treatment-
resistant depression: an open-label feasibility study. The Lancet Psychiatry 3, 619-
627, doi:10.1016/S2215-0366(16)30065-7 (2016). 
10 
Griffiths, R. R. et al. Psilocybin produces substantial and sustained decreases in 
depression and anxiety in patients with life-threatening cancer: A randomized double-
blind trial. Journal of Psychopharmacology 30, 1181-1197, 
doi:10.1177/0269881116675513 (2016). 
11 
Grob, C. S. et al. Pilot study of psilocybin treatment for anxiety in patients with 
advanced-stage cancer. Archives of General Psychiatry 68, 71-78, 
doi:10.1001/archgenpsychiatry.2010.116 (2011). 
12 
Ross, S. et al. Rapid and sustained symptom reduction following psilocybin treatment 
for anxiety and depression in patients with life-threatening cancer: A randomized 
controlled trial. Journal of Psychopharmacology 30, 1165-1180, 
doi:10.1177/0269881116675512 (2016). 
13 
Affairs, U. S. D. o. V. Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) - 
PTSD: National Center for PTSD, <> (2020). 
15 
Sheehan, D. V., Giddens, J. M. & Sheehan, I. S. Status update on the sheehan-
suicidality tracking scale (S-sts). Innovations in Clinical Neuroscience 11, 93-140 
(2014). 
16 
Friborg, O., Hjemdal, O., Rosenvinge, J. & Martinussen, M. A new rating scale for 
adult resilience: what are the central protective resources behind healthy adjustment? 
International journal of methods in psychiatric research 12, doi:10.1002/mpr.143 
(2003). 

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17 
Pinciotti, C. M., Seligowski, A. V. & Orcutt, H. K. Psychometric Properties of the 
PACT Scale and Relations With Symptoms of PTSD. Psychological Trauma: Theory, 
Research, Practice, and Policy 9, 362-369, doi:10.1037/tra0000206 (2021). 
18 
Overall, J. E. & Gorham, D. R. The Brief Psychiatric Rating Scale. Psychological 
Reports 10, 799-812, doi:10.2466/pr0.1962.10.3.799 (1962). 
19 
Zanello, A., Berthoud, L., Ventura, J. & Merlo, M. C. The Brief Psychiatric Rating 
Scale (version 4.0) factorial structure and its sensitivity in the treatment of outpatients 
with unipolar depression. Psychiatry Res 210, 626-633, 
doi:10.1016/j.psychres.2013.07.001 (2013). 
20 
Duffy, L. et al. A randomised controlled trial assessing the use of citalopram, 
sertraline, fluoxetine and mirtazapine in preventing relapse in primary care patients 
who are taking long-term maintenance antidepressants (ANTLER: ANTidepressants 
to prevent reLapse in dEpRession): study protocol for a randomised controlled trial. 
Trials 20, 319-319, doi:10.1186/s13063-019-3390-8 (2019). 
21 
Rosenbaum, J. F., Fava, M., Hoog, S. L., Ascroft, R. C. & Krebs, W. B. Selective 
serotonin reuptake inhibitor discontinuation syndrome: a randomized clinical trial. 
Biol Psychiatry 44, 77-87, doi:10.1016/s0006-3223(98)00126-7 (1998). 
 

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APPENDIX II – Declaration of Helsinki
WORLD MEDICAL ASSOCIATION DECLARATION OF HELSINKI
Ethical Principles
for
Medical Research Involving Human Participants
Adopted by the 18th WMA General Assembly
Helsinki, Finland, June 1964
and amended by the
29th WMA General Assembly, Tokyo, Japan, October 1975
35th WMA General Assembly, Venice, Italy, October 1983
41st WMA General Assembly, Hong Kong, September 1989
48th WMA General Assembly, Somerset West, Republic of South Africa, October 1996
52nd WMA General Assembly, Edinburgh, Scotland, October 2000
53rd WMA General Assembly, Washington DS, USA, October 2002
55th WMA General Assembly, Tokyo, Japan, October 2004
59th WMA General Assembly, Seoul, Republic of Korea, October 2008
and the
64th WMA General Assembly, Fortaleza, Brazil, October 2013
A. INTRODUCTION
The World Medical Association has developed the Declaration of Helsinki as a statement of 
ethical principles to provide guidance to physicians and other participants in medical research 
involving human participants. Medical research involving human participants includes 
research on identifiable human material or identifiable data.

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It is the duty of the physician to promote and safeguard the health of the people. The physician’s 
knowledge and conscience are dedicated to the fulfilment of this duty. 
The Declaration of Geneva of the World Medical Association binds the physician with the 
words, "The health of my participant will be my first consideration," and the International Code 
of Medical Ethics declares that, "A physician shall act only in the participant's interest when 
providing medical care which might have the effect of weakening the physical and mental 
condition of the participant." 
Medical progress is based on research, which ultimately must rest in part on experimentation 
involving human participants. 
In medical research on human participants, considerations related to the well-being of the 
human participant should take precedence over the interests of science and society. 
The primary purpose of medical research involving human participants is to improve 
prophylactic, diagnostic and therapeutic procedures and the understanding of the aetiology and 
pathogenesis of disease. Even the best-proven prophylactic, diagnostic, and therapeutic 
methods must continuously be challenged through research for their effectiveness, efficiency, 
accessibility and quality. 
In current medical practice and in medical research, most prophylactic, diagnostic and 
therapeutic procedures involve risks and burdens. 
Medical research is participant to ethical standards that promote respect for all human beings 
and protect their health and rights. Some research populations are vulnerable and need special 
protection. The particular needs of the economically and medically disadvantaged must be 
recognised. Special attention is also required for those who cannot give or refuse consent for 
themselves, for those who may be participant to giving consent under duress, for those who 
will not benefit personally from the research and for those for whom the research is combined 
with care. 
Research investigators should be aware of the ethical, legal and regulatory requirements for 
research on human participants in their own countries as well as applicable international 
requirements. No national ethical, legal or regulatory requirement should be allowed to reduce 
or eliminate any of the protections for human participants set forth in this Declaration. 
B. BASIC PRINCIPLES FOR ALL MEDICAL RESEARCH 
It is the duty of the physician in medical research to protect the life, health, privacy, and dignity 
of the human participant. 
Medical research involving human participants must conform to generally accepted scientific 
principles, be based on a thorough knowledge of the scientific literature, other relevant sources 
of information, and on adequate laboratory and, where appropriate, animal experimentation. 
Appropriate caution must be exercised in the conduct of research, which may affect the 
environment, and the welfare of animals used for research must be respected. 

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The design and performance of each experimental procedure involving human participants 
should be clearly formulated in an experimental protocol. This protocol should be submitted 
for consideration, comment, guidance, and where appropriate, approval to a specially 
appointed ethical review committee, which must be independent of the investigator, the 
sponsor or any other kind of undue influence. This independent committee should be in 
conformity with the laws and regulations of the country in which the research experiment is 
performed. The committee has the right to monitor ongoing trials. The researcher has the 
obligation to provide monitoring information to the committee, especially any SAEs. The 
researcher should also submit to the committee, for review, information regarding funding, 
sponsors, institutional affiliations, other potential conflicts of interest and incentives for 
participants. 
The research protocol should always contain a statement of the ethical considerations involved 
and should indicate that there is compliance with the principles enunciated in this Declaration.  
Medical research involving human participants should be conducted only by scientifically 
qualified persons and under the supervision of a clinically competent medical person. The 
responsibility for the human participant must always rest with a participant of the research, 
even though the participant has given consent. 
Every medical research project involving human participants should be preceded by careful 
assessment of predictable risks and burdens in comparison with foreseeable benefits to the 
participant or to others. This does not preclude the participation of healthy volunteers in 
medical research. The design of all studies should be publicly available. 
Physicians should abstain from engaging in research projects involving human participants 
unless they are confident that the risks involved have been adequately assessed and can be 
satisfactorily managed. Physicians should cease any investigation if the risks are found to 
outweigh the potential benefits or if there is conclusive proof of positive and beneficial results. 
Medical research involving human participants should only be conducted if the importance of 
the objective outweighs the inherent risks and burdens to the participant. This is especially 
important when the human participants are healthy volunteers. 
Medical research is only justified if there is a reasonable likelihood that the populations in 
which the research is carried out stand to benefit from the results of the research. 
The participants must be volunteers and informed participants in the research project. 
The right of research participants to safeguard their integrity must always be respected. Every 
precaution should be taken to respect the privacy of the participant, the confidentiality of the 
participant’s information and to minimise the impact of the study on the participant's physical 
and mental integrity and on the personality of the participant. 
In any research on human beings, each potential participant must be adequately informed of 
the aims, methods, sources of funding, any possible conflicts of interest, institutional 
affiliations of the researcher, the anticipated benefits and potential risks of the study and the 
discomfort it may entail. The participant should be informed of the right to abstain from 

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participation in the study or to withdraw consent to participate at any time without reprisal. 
After ensuring that the participant has understood the information, the physician should then 
obtain the participant's freely-given informed consent, preferably in writing. If the consent 
cannot be obtained in writing, the non-written consent must be formally documented and 
witnessed. 
When obtaining informed consent for the research project the physician should be particularly 
cautious if the participant is in a dependent relationship with the physician or may consent 
under duress. In that case the informed consent should be obtained by a well-informed 
physician who is not engaged in the investigation and who is completely independent of this 
relationship. 
For a research participant who is legally incompetent, physically or mentally incapable of 
giving consent or is a legally incompetent minor, the investigator must obtain informed consent 
from the legally authorised representative in accordance with applicable law. These groups 
should not be included in research unless the research is necessary to promote the health of the 
population represented and this research cannot instead be performed on legally competent 
persons. 
When a participant deemed legally incompetent, such as a minor child, is able to give assent to 
decisions about participation in research, the investigator must obtain that assent in addition to 
the consent of the legally authorised representative. 
Research on individuals from whom it is not possible to obtain consent, including proxy or 
advance consent, should be done only if the physical/mental condition that prevents obtaining 
informed consent is a necessary characteristic of the research population. The specific reasons 
for involving research participants with a condition that renders them unable to give informed 
consent should be stated in the experimental protocol for consideration and approval of the 
review committee. The protocol should state that consent to remain in the research should be 
obtained as soon as possible from the individual or a legally authorised surrogate. 
Both authors and publishers have ethical obligations. In publication of the results of research, 
the investigators are obliged to preserve the accuracy of the results. Negative as well as positive 
results should be published or otherwise publicly available. Sources of funding, institutional 
affiliations and any possible conflicts of interest should be declared in the publication. Reports 
of experimentation not in accordance with the principles laid down in this Declaration should 
not be accepted for publication. 
C. ADDITIONAL PRINCIPLES FOR MEDICAL RESEARCH COMBINED WITH 
MEDICAL CARE 
The physician may combine medical research with medical care, only to the extent that the 
research is justified by its potential prophylactic, diagnostic or therapeutic value. When medical 
research is combined with medical care, additional standards apply to protect the participants 
who are research participants. 
The benefits, risks, burdens and effectiveness of a new method should be tested against those 
of the best current prophylactic, diagnostic, and therapeutic methods. This does not exclude the 

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use of placebo, or no treatment, in studies where no proven prophylactic, diagnostic or 
therapeutic method exists. 
At the conclusion of the study, every participant entered into the study should be assured of 
access to the best-proven prophylactic, diagnostic and therapeutic methods identified by the 
study. 
The physician should fully inform the participant which aspects of the care are related to the 
research. The refusal of a participant to participate in a study must never interfere with the 
participant-physician relationship. 
In the treatment of a participant, where proven prophylactic, diagnostic and therapeutic 
methods do not exist or have been ineffective, the physician, with informed consent from the 
participant, must be free to use unproven or new prophylactic, diagnostic and therapeutic 
measures, if in the physician’s judgment it offers hope of saving life, re-establishing health or 
alleviating suffering. Where possible, these measures should be made the object of research, 
designed to evaluate their safety and efficacy. In all cases, new information should be recorded 
and, where appropriate, published. The other relevant guidelines of this Declaration should be 
followed.