A Phase 2 Open-Label Study to Assess the Safety and Immunogenicity of PXVX0317 (Chikungunya Virus Virus-Like Particle Vaccine [CHIKV VLP], Aluminum Hydroxide Adjuvanted)
Phase: PHASE2
Conditions: Chikungunya Virus
Sponsor: Bavarian Nordic

Title: A Phase 2 Open-Label Study to Assess the Safety and Immunogenicity of PXVX0317 (Chikungunya 
Virus Virus-Like Particle Vaccine [CHIKV VLP], Aluminum Hydroxide Adjuvanted) 
NCT number: NCT05065983 
Document: EBSI-CV-317-010 Protocol 
Protocol Version: v4.0 
Protocol Version Date: 07-Dec-2021 

PXVX0317  
Protocol EBSI-CV-317-010, Version No. 4.0, 
2021 
 
 
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CLINICAL STUDY PROTOCOL 
A Phase 2 Open-Label Study to Assess the Safety and Immunogenicity of 
PXVX0317 (Chikungunya Virus-Like Particle Vaccine [CHIKV VLP], 
alum-adjuvanted)  
Protocol Number: EBSI-CV-317-010 
Version 4.0  
2021 
 
Sponsor: Emergent Travel Health, Inc. 
 
 
CONFIDENTIAL 
This document is a confidential communication of the Sponsor. Acceptance of this document 
constitutes an agreement by the recipient that no unpublished information contained within 
will be published or disclosed without prior written approval, except that this document may 
be disclosed to the appropriate Ethics Committee and Regulatory Authority under the 
condition that they keep it confidential.
 
                    

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SPONSOR SIGNATORY 
Signatory: 
See electronic signature page 
  
 
 
 
 
 
Emergent BioSolutions Inc.  
Date (DDMMMYYYY) 
 
KEY STUDY CONTACT INFORMATION 
Sponsor’s Medical Monitor(s): 
 
Primary 
 
 
Phone: 
 
Backup 
 
 
Phone: 
  
Emergent BioSolutions Inc. 
 
S 
Email: 
   
 
Immediately Reportable Adverse Events: 
Email: 
   
Toll free phone: 
 
For all other contact information refer to study contact list. 
                    

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PROTOCOL SYNOPSIS 
Name of Sponsor/Company: Emergent Travel Health, Inc. 
Name of Investigational Product: PXVX0317 
Name of Active Ingredient(s): PXVX0317 vaccine is comprised of field-formulated 
CHIKV VLP 40 micrograms (μg) with 300 μg Alhydrogel® 2% administered via 
intramuscular (IM) injection in the deltoid muscle. 
Protocol Number: EBSI-CV-317-010 
Title of Study: A Phase 2 Open-Label Study to Assess the Safety and Immunogenicity of 
PXVX0317 (Chikungunya Virus-Like Particle Vaccine [CHIKV VLP], alum-adjuvanted)  
Study Center(s): Single center in the United States of America (US) 
Study Duration for Each Subject: 7 months 
Estimated Study Duration: 8 months 
Estimated Enrollment Period: 1 month 
Anticipated Start Date:
 
Estimated End Date:
  
Phase of Development: 2 
Objectives  
Primary Objectives:  
• To assess the induction of anti-CHIKV neutralizing antibody responses following a 
single adjuvant dose of PXVX0317 (40 µg CHIKV VLP adjuvanted with 300 µg 
Alhydrogel) as measured 21 days (Day 22) after vaccination  
• To assess the induction of anti-CHIKV neutralizing antibody responses following a 
single adjuvant dose of PXVX0317 as measured 7 days (Day 8), 14 days (Day 15), and 
56 days (Day 57) after vaccination  
Secondary Objective:  
• To assess the safety of a single dose of PXVX0317 in healthy adults  
Exploratory Objectives:  
• To obtain plasma and sera at Days 22 and 57 from subjects immunized with a single 
dose of PXVX0317 to support nonclinical studies 
• To characterize the kinetics of anti-CHIKV IgM, IgG, and neutralizing responses 
following a single dose of PXVX0317 as measured 7, 14, 21, and 56 days (Days 8, 15, 
22, and 57 respectively) after vaccination 
                    

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• To characterize T and B cell responses following a single dose of PXVX0317 with 
collections of peripheral blood mononuclear cells (PBMCs) 7, 14, 21, and 56 days 
(Days 8, 15, 22, and 57) after vaccination 
Methodology 
Study Design: This is an open-label, single arm Phase 2 study in healthy adults 18 to 45 
years of age. Approximately 25 subjects are targeted for enrollment. 
This study has a screening period of 30 days, a treatment and observation period from Day 
1 to Day 22, and a follow-up period through Day 183. Subjects will receive CHIKV VLP 
at a dose of 40 µg in combination with 300 µg Alhydrogel on Day 1, and have follow-up 
visits on Day 8, Day 15, and Day 22. A plasmapheresis procedure and collection of serum 
will occur on Day 22. A phone call follow-up visit will occur on Day 29, followed by a 
second plasmapheresis procedure and collection of serum at Day 57. A phone call follow-
up visit to assess safety and concomitant medications will occur on Day 64. An end of 
study (EOS) phone call follow-up visit to assess safety and concomitant medications will 
occur on Day 183. 
Details of visits, visit windows, and procedures are provided in the Schedule of Events 
below. After signing the informed consent form, subjects will undergo screening 
procedures up to 30 days before a single-dose injection on Day 1. Subjects will be 
observed in clinic for 30 minutes after injection and vital signs obtained at least 30 minutes 
but no more than 60 minutes after injection. Local and systemic solicited adverse events 
(AEs) occurring within 7 days after injection (to Day 8) will be recorded by the subject 
using a memory aid. Subjects will be specifically asked to record local injection site events 
(pain, redness, swelling) and systemic events (oral temperature ≥100.4º F, chills, fatigue, 
headache, myalgia, joint pain, and nausea). Memory aids will be reviewed at the Day 8 
visit. Unsolicited AEs will be monitored from Day 1 through Day 29; serious adverse 
events (SAEs) and adverse events of special interest (AESI) will be monitored for the 
duration of the study (to Day 183). Information on all concomitant medications used 
through Day 29 will be recorded; after Day 29, only information on concomitant 
medications used for the treatment of an SAE or AESI will be recorded. After screening, 
blood will be collected for immunogenicity assessments at Days 1 (pre-vaccination), 8, 15, 
22, and 57.   
Subjects who discontinue study participation before Day 22 (or who do not undergo Day 
22 plasmapheresis for other reasons) may be replaced.  
A final analysis of data collected throughout the study from all subjects will be performed 
after the last subject has completed the study and the immunogenicity and safety data have 
been cleaned and locked. 
Serology: Serum neutralizing antibody (SNA) responses to CHIKV VLP will be 
determined by a luciferase based anti-CHIKV neutralization assay (CHIKV-luc). Titers are 
expressed as the reciprocal of the serum dilution achieving 80% neutralization (NT80). 
Anti-CHIKV specific IgG and IgM antibody levels will be determined by enzyme-linked 
                    

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immunosorbent assay (ELISA). Peripheral blood mononuclear cells will be collected for 
exploratory analyses of T and B cell immune responses. 
Number of Subjects (Planned): 25 
Study Population: Healthy adults 18 to 45 years of age 
Inclusion Criteria:  
Subjects must meet all the following criteria to be enrolled: 
1. 
Able and willing to provide informed consent voluntarily signed by subject.  
2. 
Any gender, 18 to 45 years of age (inclusive). 
3. 
Generally healthy, in the opinion of the Investigator, based on medical history, 
physical examination, and screening laboratory assessments.  
4. 
Women who are either: 
i. 
Not of childbearing potential (CBP): pre-menarche, anatomically sterile, or post-
menopausal (defined as ≥12 months without menses). 
or: 
ii. 
Meeting all the below criteria: 
• Negative urine pregnancy test at screening visit and 
• Negative urine pregnancy test immediately prior to dosing at Day 1 and 
• Using an acceptable method of contraception (if female of childbearing potential) 
for the duration of participation, such as:  
• Hormonal contraceptives (e.g., implants, pills, patches) initiated ≥30 days prior 
to dosing or 
• Intrauterine device (IUD) inserted ≥30 days prior to dosing or 
• Double barrier type of birth control (male condom with female diaphragm, 
male condom with cervical cap). 
Exclusion Criteria:  
Subjects who meet any of the following criteria cannot be enrolled: 
1. 
Currently pregnant, breastfeeding, or planning to become pregnant during the study. 
2. 
Body Mass Index (BMI) ≥35 kg/m2. 
3. 
Positive laboratory evidence of current infection with human immunodeficiency virus 
(HIV-1, HIV-2), hepatitis C virus (HCV) or hepatitis B virus (HBV). 
4. 
History of severe allergic reaction or anaphylaxis to any component of the 
investigational product (IP). 
                    

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5. 
History of known congenital or acquired immunodeficiency that could impact 
response to vaccination (e.g., leukemia, lymphoma, generalized malignancy, 
functional or anatomic asplenia, alcoholic cirrhosis).  
6. 
Prior or anticipated receipt of immunomodulatory or immunosuppressive therapy 
from six months prior to screening through Day 64. 
7. 
Receipt or anticipated receipt of blood or blood-derived products from 90 days prior 
to screening through Day 64. 
8. 
Acute disease within the last 14 days (subjects with an acute mild febrile illness can 
be considered for a deferral of vaccination two weeks after the illness has resolved 
and treatment has been completed). 
9. 
Clinically significant cardiac, pulmonary, respiratory, rheumatologic, or other chronic 
disease, in the opinion of the Investigator. This may include chronic illness requiring 
hospitalization in the last one month prior to screening.  
10. Enrollment in an interventional study and/or receipt of another investigational 
product from 30 days prior to screening through the duration of study participation. 
11. Receipt or anticipated receipt of any vaccine from 30 days prior to screening through 
Day 64. 
12. Prior receipt of an investigational CHIKV vaccine/product. 
13. Detectable baseline anti-CHIKV IgG antibody as determined by ELISA.  
14. Any other condition that, in the opinion of the Investigator, could adversely impact 
the subject’s participation or the conduct of the study, creates an unacceptable risk to 
the subject, or may interfere with the conduct of the study or validity of the data. 
15. Restricted venous access that would prevent the collection of plasma and serum 
necessary for participation. 
16. Weight <110 pounds. 
Investigational Product (IP), Dosage and Mode of Administration: PXVX0317 
vaccine is comprised of field-formulated CHIKV VLP 40 μg with 300 μg Alhydrogel 2% 
administered via intramuscular (IM) injection in the deltoid muscle. 
Reference Therapy, Dosage and Mode of Administration: There will be no control 
group for this study. 
Study Endpoints/Outcome Measure(s)  
Primary: The geometric mean titer (GMT) of anti-CHIKV neutralizing antibody 
determined by luciferase-based CHIKV-luc assay at Day 22. 
Immunogenicity Endpoint: Anti-CHIKV neutralization response data will be evaluated 
from Day 1 through Day 57. The primary analysis will be based on anti-CHIKV 
neutralization titers measured at 21 days after injection (Day 22) for the modified intent to 
                    

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treat (mITT) population, defined as all subjects who are vaccinated and have at least one 
post-injection anti-CHIKV SNA NT80 result.  
The derived immunogenicity endpoints are listed briefly below.  
Geometric Mean Titer (GMT): Anti-CHIKV neutralization titers will be logarithmically 
transformed (base10). The GMTs and associated 95% confidence intervals (CI) will be 
computed by exponentiating the corresponding log-transformed means and 95% 
confidence limits.  
Proportion (percentage) of subjects with anti-CHIKV titer exceeding defined cut-off 
values: The proportion (percentage) of subjects with antibody responses exceeding 
stipulated cut-off values (e.g., titers of 15 or 100), together with a two-sided 95% CI based 
on the Wilson method, will be tabulated at all serum collection time points (Days 8, 15, 22, 
and 57). 
Proportion (percentage) of subjects with at least a four-fold rise over baseline in anti-
CHIKV titer:  The proportion (percentage) of subjects with post-vaccination titers at least 
four times higher than pre-vaccination, together with a two-sided 95% CI based on the 
Wilson method, will be tabulated at all serum collection time points (Days 8, 15, 22, and 
57). 
Safety Endpoints: Subjects who receive a study injection will have data collected for 
safety analysis. The safety objectives will be assessed by analysis of the incidence rate for 
all local and systemic post-injection solicited events and other AEs collected during the 7 
days following injection. Safety analysis will also include the occurrence of any 
unsolicited AEs through Day 29, and SAEs and AESIs collected through Day 183 end of 
study. In addition, any AEs occurring within 30 minutes of the plasmapheresis procedures 
at Days 22 and 57 will be collected. Data listings will include all subjects, including screen 
failures. The Principal Investigator will assess causality and severity.  
Statistical Methods 
Sample Size Considerations: The sample size (N=25) is based on the number of subjects 
needed to provide adequate plasma and sera for non-clinical studies. 
                    

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PBMC Collection (B+T cells)13 
 
X5 
X 
X 
X 
 
X 
 
 
X 
Blood for ELISA (IgM/IgG)13 
 
X5 
X 
X 
X 
 
X 
 
 
X 
Plasmapheresis and Serum 
Collection (for nonclinical 
studies)13 
 
 
 
 
X 
 
X 
 
 
 
D/C, discontinuation; n/a, not applicable; HBsAg, Hepatitis B surface antigen; anti-HCV, Hepatitis C virus antibody; HIV1/2 Ag/Ab, human immunodeficiency virus 
antigen/antibody; CHIKV, chikungunya virus; Con Med, concomitant medication; ELISA, enzyme-linked immunosorbent assay; min, minute; PBMC, peripheral blood 
mononuclear cells; EOS, End of Study. 
1Complete physical examination at Screening Visit only; Directed physical examination, if indicated by updated medical history at Visit 2 and as needed in subsequent visits.  
2Only if before Day 57. 
3To be taken prior and after Study Vaccine administration. 
4Urine pregnancy test at Screening, prior to Study Vaccine administration and prior to plasmapheresis. 
5Done pre-vaccination. 
6If the visit occurs within seven days after Study Vaccine administration. 
7Adverse events occurring 30 mins post plasmapheresis at Day 22 and 57 will be collected. 
8Confirmation of continued eligibility (inclusion/exclusion criteria met) prior to plasmapheresis procedure. 
9Subjects will be monitored by study staff for signs of an acute adverse reaction for 30 mins after injection but no more than 60 mins after injection. 
10Solicited AEs from Days 1 to 8, Unsolicited AEs to Day 29; After Day 29, collect SAE and AESI only for the duration of the study (Day 183 EOS). 
11After Day 29, concomitant medications are collected only for SAEs and AESI. 
12If anti-HCV positive HCV RNA testing will be performed. 
13Table summarizing bloodwork by procedure, assay, collection tubes, and the total volume of plasma and/or serum by visit is provided in Appendix I. 
                    

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TABLE OF CONTENTS 
SCHEDULE OF EVENTS ......................................................................................................9 
1 
BACKGROUND INFORMATION ............................................................................17 
1.1 
Name and Description of Investigational Product ............................................17 
1.2 
Chikungunya Virus and Disease Background ..................................................17 
1.3 
Justification for Use of Investigational PXVX0317 Vaccine ............................18 
1.3.1 
Summary of Animal Studies ...............................................................................19 
1.3.2 
Summary of Findings from Clinical Studies ......................................................20 
1.3.3 
Rationale for Dosage and Route of Administration ............................................22 
2 
STUDY OBJECTIVES AND PURPOSE ...................................................................22 
2.1 
Primary Objectives ..............................................................................................22 
2.2 
Secondary Objective ............................................................................................22 
2.3 
Exploratory Objectives ........................................................................................23 
3 
STUDY DESIGN ...........................................................................................................23 
3.1 
Study Description .................................................................................................23 
3.1.1 
Study Centers ......................................................................................................23 
3.1.2 
Number of Subject (Planned)..............................................................................23 
3.1.3 
Estimated Study Duration ...................................................................................23 
3.2 
Schematic Diagram of Study Design ..................................................................24 
3.3 
Description of Study Assessments ......................................................................25 
3.3.1 
Review of Eligibility Criteria..............................................................................25 
3.3.2 
Medical History and Demography ......................................................................25 
3.3.3 
Physical Examination..........................................................................................25 
3.3.4 
Vital Signs ...........................................................................................................25 
3.3.5 
Laboratory Tests .................................................................................................26 
3.3.6 
Immunogenicity Sample .....................................................................................26 
3.3.7 
Pregnancy Testing and Contraception ................................................................26 
3.3.8 
Investigational Product Administration ..............................................................26 
3.3.9 
Acute Observation After IP Administration .......................................................27 
3.3.10 Solicited Adverse Events ....................................................................................27 
3.3.11 Unsolicited Adverse Events ................................................................................28 
3.3.12 Serious Adverse Events and Adverse Events of Special Interest .......................28 
3.3.13 Plasmapheresis Procedure ...................................................................................28 
3.4 
End of Study .........................................................................................................28 
4 
SELECTION AND WITHDRAWAL OF SUBJECTS .............................................29 
4.1 
Subject Inclusion Criteria ...................................................................................29 
4.2 
Subject Exclusion Criteria ..................................................................................29 
                    

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4.3 
Withdrawal of Subjects .......................................................................................30 
4.3.1 
Subject Consent Withdrawal ...............................................................................30 
4.3.2 
Investigator-Based Subject Withdrawal .............................................................31 
4.3.3 
Follow-up for Withdrawn Subjects .....................................................................31 
4.3.4 
Documentation of Withdrawal/Discontinuation .................................................31 
4.3.5 
Subject Replacement ...........................................................................................32 
5 
TREATMENT OF SUBJECTS ...................................................................................32 
5.1 
Investigational Product(s) ...................................................................................32 
5.1.1 
CHIKV VLP .......................................................................................................32 
5.1.2 
Alum Adjuvant....................................................................................................33 
5.1.3 
Labeling ..............................................................................................................33 
5.1.4 
Investigational Product Shipment .......................................................................33 
5.1.5 
Storage Conditions ..............................................................................................34 
5.1.6 
Other Supplies .....................................................................................................34 
5.1.7 
Preparation ..........................................................................................................34 
5.1.8 
Drug Accountability............................................................................................35 
5.2 
Study Procedures and Assessments by Visit .....................................................35 
5.2.1 
Screening (Visit 1, within 30 days of Day 1)......................................................35 
5.2.2 
Day 1 (Baseline and Administration of IP) Visit 2 .............................................36 
5.2.3 
Day 8 (+3) Visit 3 ...............................................................................................37 
5.2.4 
Day 15 (±2) Visit 4 .............................................................................................37 
5.2.5 
Day 22 (+5) Plasmapheresis Visit 5 ...................................................................37 
5.2.6 
Day 29 (-1/+5) Telephone Contact for Visit 6 ....................................................38 
5.2.7 
Day 57 (+5) Plasmapheresis Visit 7 ...................................................................38 
5.2.8 
Day 64 (-1/+5d) Telephone Contact for Visit 8 ..................................................38 
5.2.9 
Day 183 (-14/+7d) Telephone Contact for Visit 9 End of Study ........................38 
5.2.10 Early Discontinuation/Withdrawal Visit.............................................................38 
5.2.11 Unscheduled Visits .............................................................................................39 
5.2.12 COVID-19 Related Considerations ....................................................................39 
5.3 
Prior and Concomitant Medications ..................................................................39 
5.3.1 
Required Concomitant Medications ...................................................................39 
5.4 
Procedures for Monitoring Subject Compliance ..............................................39 
6 
IMMUNOGENICITY ASSESSMENT .......................................................................40 
6.1 
Immunogenicity Analysis ....................................................................................40 
7 
SAFETY ASSESSMENTS AND REPORTING ........................................................41 
7.1 
Definitions .............................................................................................................41 
7.1.1 
Adverse Event .....................................................................................................41 
7.1.2 
Solicited Adverse Event ......................................................................................41 
7.1.3 
Unsolicited Adverse Event .................................................................................42 
7.1.4 
Adverse Event of Special Interest .......................................................................42 
7.1.5 
Serious Adverse Event ........................................................................................42 
                    

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7.1.6 
Suspected Unexpected Serious Adverse Reaction ..............................................42 
7.1.7 
Severity of Adverse Events .................................................................................42 
7.1.8 
Causality of Adverse Events ...............................................................................43 
7.2 
Eliciting Adverse Events......................................................................................43 
7.3 
Reporting Requirements for Immediately Reportable Events ........................43 
7.3.1 
Principal Investigator’s Reporting Requirements ...............................................43 
7.3.2 
Sponsor’s Reporting Requirements ....................................................................44 
7.4 
Reporting of Other Information - Unanticipated Problems ............................45 
7.5 
Follow-up of Adverse Events ..............................................................................46 
7.5.1 
Follow-up of Nonserious Adverse Events ..........................................................46 
7.5.2 
Follow-up of Serious Adverse Events or Adverse Events of Special 
Interest.................................................................................................................46 
8 
STATISTICAL CONSIDERATIONS ........................................................................47 
8.1 
Sample Size Determinations................................................................................47 
8.2 
Analysis Populations ............................................................................................47 
8.3 
Study Endpoints ...................................................................................................47 
8.3.1 
Primary Endpoints ..............................................................................................47 
8.3.2 
Secondary Endpoints ..........................................................................................47 
8.3.3 
Exploratory Endpoints ........................................................................................48 
8.4 
Handling Missing Data ........................................................................................48 
8.5 
Analysis of Disposition, Demographic and Baseline Characteristics ..............48 
8.6 
Immunogenicity Analysis ....................................................................................48 
8.7 
Safety Analysis .....................................................................................................49 
8.7.1 
Exposure .............................................................................................................49 
8.7.2 
Adverse Events ...................................................................................................49 
8.7.3 
Clinical Laboratory Data.....................................................................................51 
8.7.4 
Physical Examinations ........................................................................................51 
8.7.5 
Vital Signs ...........................................................................................................51 
8.7.6 
Prior and Concomitant Medications ...................................................................51 
8.7.7 
Other Safety Variables ........................................................................................51 
8.7.8 
Subgroup Analysis ..............................................................................................51 
8.7.9 
Interim Analysis ..................................................................................................51 
9 
DATA HANDLING AND RECORD KEEPING .......................................................51 
9.1 
Source Documents and Access ............................................................................51 
9.2 
Data Management ................................................................................................52 
9.3 
Data Collection and Discrepancy Management ................................................52 
9.4 
Laboratory Data...................................................................................................53 
9.5 
File Management at the Investigational Site .....................................................53 
9.6 
Records Retention at the Investigational Site ...................................................53 
9.7 
Deviations from the Protocol ..............................................................................53 
10 
QUALITY CONTROL AND ASSURANCE..............................................................54 
                    

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10.1 
Monitoring ............................................................................................................54 
10.2 
Auditing ................................................................................................................54 
11 
ETHICS AND RESPONSIBILITY .............................................................................54 
11.1 
Informed Consent ................................................................................................55 
11.2 
Institutional Review Board (IRB).......................................................................55 
11.3 
Compensation for Injury .....................................................................................55 
11.4 
Subject Confidentiality ........................................................................................56 
11.5 
Future Use of Stored Samples .............................................................................56 
12 
ADMINISTRATIVE AND LEGAL REQUIREMENTS ..........................................56 
12.1 
Sponsorship ..........................................................................................................56 
12.2 
Protocol Amendments .........................................................................................56 
12.3 
Clinical Study Registration .................................................................................57 
12.4 
Publication Policy.................................................................................................57 
12.5 
Terminating the Study .........................................................................................57 
12.6 
Terminating the Study at an Individual Site .....................................................57 
13 
REFERENCES ..............................................................................................................58 
APPENDIX 
APPENDIX I 
SUMMARY OF BLOODWORK ........................................................61 
APPENDIX II 
GRADING SCALE ...............................................................................62 
LIST OF TABLES 
Table 1   Needle Length for IM Injections by Sex and Weight ...............................................27 
Table 2   CHIKV VLP Drug Product .......................................................................................33 
LIST OF FIGURES 
Figure 1   Chikungunya virus Global Burden ..........................................................................18 
Figure 2   EBSI-CV-317-010 Schematic Diagram of Study Design .......................................24 
                    

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LIST OF ABBREVIATIONS 
AE  
Adverse Event  
AESI 
Adverse Event of Special Interest 
Ag/Ab 
Antigen/Antibody 
BMI 
Body Mass Index 
CBP 
Childbearing Potential 
CDC 
Centers for Disease Control and Prevention 
CFR 
Code of Federal Regulations 
CHIKV  
Chikungunya Virus  
CHIKV VLP 
Chikungunya Virus-Like Particle 
CI  
Confidence Interval  
CS 
clinically significant 
ºC 
Degrees Celsius 
ºF 
Degrees Fahrenheit  
DMP  
Data Management Plan  
DNA 
Deoxyribonucleic Acid 
eCRF  
Electronic Case Report Form  
EDC  
Electronic Data Capture  
ELISA 
Enzyme-Linked Immunosorbent Assay 
EOS 
End of Study 
FDA  
US Food and Drug Administration  
GCP  
Good Clinical Practice  
GMFI 
Geometric Mean Fold Increase 
GMT  
Geometric Mean Titer  
HBSag 
Hepatitis B Surface antigen 
HCV  
Hepatitis C Virus  
HEK 
Human Embryonic Kidney 
HIV  
Human Immunodeficiency Virus  
IB 
Investigator’s Brochure 
ICF  
Informed Consent Form  
ICH  
International Conference on Harmonization  
IM  
Intramuscular  
IND  
Investigational New Drug  
IP  
Investigational Product 
IPD  
Important Protocol Deviation  
IRB  
Institutional Review Board  
                    

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IUD 
Intrauterine Device 
LLOQ 
Lower Limit of Quantitation 
MedDRA  
Medical Dictionary of Regulatory Activities  
µg 
Microgram 
mL 
Milliliter 
mITT 
Modified Intent-to-Treat Population 
MM  
Medical Monitor  
NIH 
National Institutes of Health 
NT  
Neutralization Titer  
PBMC 
peripheral blood mononuclear cells 
PFU 
Plaque Forming Unit 
PT 
Preferred term 
RNA 
Ribonucleic Acid 
RT-PCR 
Reverse Transcriptase Polymerase Chain Reaction 
SAE  
Serious Adverse Event  
SAP  
Statistical Analysis Plan  
SNA 
Serum Neutralizing Antibody 
SOC 
System Organ Class 
SUSAR 
Serious and Unexpected Suspected Adverse Reactions 
VLP  
Virus-Like Particle  
VRC 
Vaccine Research Center 
US  
United States of America 
WHO  
World Health Organization  
w/w 
Weight per Weight 
 
 
                    

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1 
BACKGROUND INFORMATION 
1.1 
Name and Description of Investigational Product 
PXVX0317 is a chikungunya virus-like particle (CHIKV VLP) vaccine. The vaccine is 
comprised of CHIKV VLP adsorbed on Alhydrogel 2% adjuvant (2% weight per weight 
[w/w]) aqueous suspension of aluminum hydroxide) and stabilized with formulation buffer, 
which is field-formulated as a single dose of 0.8 milliliters (mL) in a syringe to be 
administered intramuscularly (IM) in the deltoid muscle. For additional product information, 
see Section 5.1 and the PXVX0317 Investigator’s Brochure (IB) (1).   
The target indication for PXVX0317 vaccine is active immunization to prevent disease 
caused by chikungunya virus. 
1.2 
Chikungunya Virus and Disease Background 
Chikungunya virus is an arthropod-borne alphavirus of the family Togaviridae. The CHIKV 
virion contains a positive-sense single-strand ribonucleic acid (RNA) genome with a long 
open reading frame coding for capsid (C) and envelope (E1, E2, E3, and 6K) structural 
proteins, together with four non-structural proteins (nsP1, nsP2, nsP3, and nsP4) required for 
replication of the virus. Since the first case reports of CHIKV in a 1952-1953 outbreak in 
Tanzania (2), this disease has been endemic in Africa and parts of Asia with transmission to 
humans occurring through Aedes aegypti and more recently via Aedes albopictus mosquitoes 
(3).  
Beginning in 2014, CHIKV disease cases were reported among United States of America 
(US) travelers returning from affected areas in the Americas and local transmission was 
identified in Florida, Puerto Rico, and the US Virgin Islands. According to the US Centers 
for Disease Control and Prevention (CDC) as of September 17, 2019, approximately 117 
countries or territories have documented cases of CHIKV infection, excluding those 
countries where only imported cases have been documented (Figure 1 adapted from (4)). 
Although mosquitoes are the primary mode of transmission of CHIKV, blood-borne 
transmission via needle stick is possible. Maternal-fetal transmission has been documented 
during pregnancy (5).  
                    

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Figure 1   Chikungunya virus Global Burden 
 
Following an incubation period of 2 to 12 days, acute clinical manifestations include high 
fever, rash, gastrointestinal complications, headache, muscle pain, nausea, fatigue, myalgia, 
and joint pain (6, 7, 8). The most classic symptom of CHIKV is a debilitating polyarthralgia 
that is present in greater than 90% of cases (9). This acute phase resolve within several 
weeks, but joint pain and arthritis may persist for months or years in over 25% to 40% of 
infected individuals (10). 
There are currently no approved vaccines to prevent CHIKV infection or disease. However, 
protection against subsequent infection has been shown to correlate with the presence of 
CHIKV serum antibodies that neutralize the virus in vitro (11, 12). 
There are currently no approved vaccines to prevent CHIKV infection or disease. However, 
protection against subsequent infection has been shown to correlate with the presence of 
CHIKV serum antibodies that neutralize the virus in vitro (11, 12). 
1.3 
Justification for Use of Investigational PXVX0317 Vaccine  
The National Institutes of Health (NIH) Vaccine Research Center (VRC) initiated the 
development of the CHIKV VLP vaccine, designated VRC-CHKVLP059-00-VP. The VRC 
completed Phase 1 (VRC 311) (13, 14) and Phase 2 (VRC 704) (15, 16) clinical studies (15, 
16). PaxVax Inc. then manufactured the vaccine as PXVX0317, conducted a mouse 
immunogenicity study showing comparability to the VRC-CHKVLP059-00-VP vaccine, and 
proceeded to a Phase 2 study (PXVX-CV-317-001) (17). 
was acquired by 
                    

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Emergent BioSolutions, Inc. in 
 has been renamed Emergent Travel Health Inc. 
(Emergent), and was the Sponsor of two Phase 2 studies (PXVX-CV-317-001 (17), EBSI-
CV-317-002 (18), and this Phase 2 study (EBSI-CV-317-010).  
1.3.1 Summary of Animal Studies 
The Sponsor conducted a study in mice that demonstrated comparability between the 
immune responses induced by the VRC-CHKVLP059-00-VP and PXVX0317 vaccines. A 
model development challenge study was conducted in cynomolgus macaque nonhuman 
primates (NHPs) to determine the appropriate CHIKV challenge dose to induce symptoms of 
arthralgia. This study revealed that high CHIKV challenge doses induced inflammation of 
the joints and surrounding tissues in infected animals, and a scoring system was developed to 
measure the degree of joint infiltration. Subsequently, an active vaccination and challenge 
study was conducted with the PXVX0317 vaccine. NHPs received two IM immunizations 
(on Study Days 0 and 28) with VLP (1.25, 6, or 20 µg) adjuvanted with alum (300 µg), VLP 
alone (20 µg) or alum alone, followed by high-dose challenge with 107 plaque forming units 
(PFU) of CHIKV (strain LR2006-OPY1).   
Data from the study demonstrate that all three dose levels of the PXVX0317 vaccine, 
including 20 µg without alum, induced a robust immune response as measured by the 
CHIKV-luc assay, even after a single immunization. Importantly, the addition of alum 
increased the pre-challenge SNA titers compared to the VLP vaccine without alum. 
Furthermore, vaccination completely protected NHPs from infectious viremia, as measured 
by plaque assay on serum from challenged animals, which measures replicating virus. Joint 
pathology scores in the active vaccination study demonstrate that vaccination with 
PXVX0317 protects NHPs from joint infiltration in a dose-dependent manner. Reverse 
transcriptase polymerase chain reaction (RT-PCR) analysis, which measures presence of 
viral RNA, showed significantly lower levels of viral RNA in plasma and joint tissues of 
vaccinated animals compared with animals that had received only alum. Taken together, 
these data suggest that vaccination induced anti-CHIKV SNA protects cynomolgus macaques 
from developing CHIKV disease following viral challenge.  
In addition, Emergent conducted a passive transfer and challenge study in cynomolgus 
macaque NHPs. Human IgG purified from plasma of volunteers vaccinated with PXVX0317 
was passively transferred to NHPs at three dose levels (5, 15 and 100 mg/kg, resulting in 
SNA titers at time of challenge of 1:38, 1:101, and 1:644, respectively) followed by CHIKV 
LR2006-OPY1 challenge. The in-life portion of the study has been completed. All three dose 
levels of IgG from plasma of PXVX0317 vaccinated subjects completely protected NHPs 
from infectious viremia as measured by plaque assay. IgG administration also appeared to 
protect NHPs from joint pathology and viral RNA in plasma, as measured by RT-PCR, in a 
dose-dependant manner. IgG also protected NHPs from the presence of viral RNA in joint 
tissues in a non-dose-dependant manner.  
                    

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1.3.2 Summary of Findings from Clinical Studies 
VRC 311 
The safety and immunogenicity of VRC-CHKVLP059-00-VP were evaluated under BB-IND 
14907 in VRC 311, a Phase 1 open-label, dose-escalation study (13, 14). Healthy adult 
participants 18 to 50 years of age were assigned to sequential dose level groups to receive IM 
injections of 10 µg, 20 µg, or 40 µg (without adjuvant) on Weeks 0, 4, and 20, with follow-
up for 44 weeks after enrollment. The primary endpoints were safety and tolerability of the 
vaccine. Secondary endpoints were CHIKV-specific immune responses assessed by 
neutralizing antibody assay and ELISA (13, 14). Post-hoc analysis of SNA by a luciferase-
based assay was also performed by the Sponsor (19).  
All injections were well tolerated, with no Serious Adverse Events (SAE) reported. The most 
common local reaction was mild injection site pain (36%) and the most common systemic 
reaction was mild malaise (24%). No moderate or severe reactogenicity was observed (13, 
14). 
Neutralizing antibodies were detected in all dose groups after the second vaccination. The 
GMT of the half maximum inhibitory concentration (IC50) was 2688 in the 10 µg group, 
1775 in the 20 µg group, and 7246 in the 40 µg group, and a significant boost occurred after 
the third vaccination in all dose groups (10 µg group p=0.0197, 20 µg group p<0.0001, and 
40 µg group p<0.0001). Four weeks after the third vaccination, the GMT of the IC50 was 
8745 for the 10 µg group, 4525 for the 20 µg group, and 5390 for the 40 µg group (13, 14). 
These findings were confirmed by both a plaque reduction assay and the Sponsor’s 
luciferase-based assay (CHIKV-luc) (19), confirming both the immunogenicity of the VLP 
and the suitability of CHIKV-luc for future studies (see Section 6.1 for assay details).  
VRC 704 
The NIH’s VRC 704 was a Phase 2 study conducted at multiple CHIKV-endemic sites in the 
Caribbean (15, 16). The study was a double-blind, placebo-controlled study with 200 
subjects receiving 20 µg of CHIKV VLP and 200 receiving placebo in a 2-dose series at 
Weeks 0 and 4. The study was initiated in 2016 and completed in 2018. Approximately 20% 
of subjects demonstrated detectable CHIKV neutralizing antibodies at baseline using the 
focus reduction neutralization test (FRNT) reported as EC50 values. EC50 is the dilution of 
sera that inhibits 50% infection in viral neutralization assay. CHIKV VLP appeared safe and 
well tolerated in subjects who were followed through Week 72, with no related SAEs or 
other safety concerns (15, 16). CHIKV VLP appeared highly immunogenic, with a GMT of 
2004.5 and 99.5% of recipients having neutralizing antibodies at Week 8. A boosting effect 
of SNA after administration of CHIKV VLP was also observed in subjects with baseline 
CHIKV neutralizing antibodies (15, 16). 
Specimens from VRC 704 were also analyzed by the Sponsor, using the CHIKV-luc assay. A 
subgroup analysis was performed on subjects without baseline CHIKV neutralizing activity. 
Using a more stringent 80% neutralization cut-off (NT80), the GMT was 123 at Week 4 and 
1701 at Week 8. After Week 8, antibody levels declined by about 1 log but remained 
                    

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elevated above baseline, with GMTs of 213 at Week 24, 115 at Week 48, and 100 at Week 
72, indicating that long-term protection can potentially be achieved without the need for 
booster dose(s). These results demonstrated that CHIKV VLP was safe and immunogenic in 
adults in CHIKV-endemic areas, including those with serologic evidence of previous CHIKV 
exposure. The most frequently reported local adverse event (AE) was pain/tenderness at the 
injection site reported as mild by 58 of 197 (29%) vaccine recipients who received at least 
one study injection and as moderate by 3/197 vaccine recipients (2.0%). The most frequently 
reported systemic AEs were mild or moderate headache reported by 54 of 197 (27.4%) 
vaccine recipients, malaise (53/197, 26.9%), and myalgia (46/197, 23.4%) (15, 16). Placebo 
recipients reported these systemic reactogenicity symptoms at similar frequencies. One 
vaccine recipient (0.5%) experienced a headache graded as severe following the second 
vaccination. A total of 16 SAEs in 15 (3.8%) subjects were reported, all were assessed as 
unrelated to the investigational product (IP) (i.e., CHIKV VLP or placebo). All potentially 
related AEs resolved without clinical sequelae (15, 16). 
Taken together, the findings from VRC 311 and VRC 704 suggest that VRC-CHKVLP059-
00-VP is well-tolerated and immunogenic in both CHIKV-exposed and CHIKV-naïve adults. 
PXVX-CV-317-001 
The Phase 2 clinical study (PXVX-CV-317-001) conducted in the US compared multiple 
dose and dosing regimens of CHIKV VLP in healthy adults aged 18 to <46 years (17). The 
dosages of CHIKV VLP ranged from 6 µg to 40 µg, adjuvanted. These doses were below or 
approximately equivalent to those used in VRC 311 (13, 14) and VRC 704 (15, 16) clinical 
studies. PXVX0317 vaccine was immunogenic across all dose groups as measured by 
CHIKV-luc assay. Immunogenicity data reported as 80% antibody neutralization titer (NT80) 
values supporting the benefit of adjuvant was evident after one dose but not two doses. There 
was a clear dose-response relationship in GMT. Subjects receiving 20 µg on the standard 
schedule (Days 1 and 29), either unadjuvanted or adjuvanted, had the highest Day 57 GMT at 
2057 and 2024 respectively, similar to those of CHIKV VLP recipients in the VRC 704 study 
(15, 16). Subjects receiving the single 40 µg dose (Group 8) demonstrated only slightly lower 
GMT levels (1713 at Day 57, i.e., 28 days after vaccination); all other dose groups 
demonstrated a GMT range of 920 to 1563 at Day 57. Seroconversion rates showed that with 
a single dose administered, up to 98% of study participants produced a neutralizing antibody 
response by Day 8. Further, the immune response was shown to be persistent through the 12-
month visit, including in the one dose 40 µg CHIKV VLP regimen. There was a clear dose-
response relationship in GMT, with the Group 8 40 µg CHIKV VLP + 300 µg alum adjuvant 
single dose resulting in 86% sero-response (titers ≥40) 7 days post-vaccination as well as the 
highest GMTs at Day 182 and Day 365. Sero-response was well maintained at 365 days in all 
groups. Group 8 was followed through Day 760 and demonstrated persistent sero-response 
for 2 years post vaccination (17). Two additional open-label groups were sequentially added 
to the study in order to provide plasma for NHPs in planned passive transfer studies; one 
group received two doses of the adjuvanted 20 µg on the standard 4-week schedule (N=20) 
and one group received a single alum-adjuvanted 40 µg dose at Day 1 (N=10).   
                    

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EBSI-CV-317-002 
The Phase 2 clinical study (EBSI-CV-317-002) conducted at two sites in the US compared 
the safety and immunogenicity of a 40 µg CHIKV VLP + 300 µg alum adjuvant single dose 
in prior recipients of other alphavirus vaccines versus alphavirus vaccine-naïve controls (18).  
The thirty prior alphavirus vaccine recipients and thirty gender and age-matched vaccine-
naïve controls were vaccinated and followed for 6 months. There were no differences 
between the groups in anti-CHIKV neutralizing antibody GMTs at Day 22 and no new safety 
signals were identified. Final data analysis is pending. 
1.3.3 Rationale for Dosage and Route of Administration 
The regimen of PXVX0317 selected for this study is 40 µg of VLP with alum adjuvant 
administered in a single IM dose on Day 1. The alum dose of 300 µg is within the range of 
doses of alum adjuvants used in many licensed vaccines, including VLP-based vaccines. This 
dose also creates a concentration ratio to PXVX0317 that achieves high (~90%) levels of 
adsorption, thought to enhance both immunogenicity and short-term stability. The IM route 
of administration is consistent with that in previous clinical studies (VRC 311 (13, 14), VRC 
704 (15, 16),  PXVX-CV-317-001, and EBSI-CV-317-002 (17)). This regimen was selected 
by an interim analysis of the PXVX-CV-317-001 study data. All regimens tested in PXVX-
CV-317-001 were given to groups of 50 to 53 healthy adults and all resulted in 100% 
seroconversion by Day 57. The group receiving a single dose of 40 µg plus alum showed the 
highest anti-CHIKV SNA GMT at Day 182 and Day 365.  
The PXVX0317 vaccine (40 µg CHIKV VLP + 300 µg alum adjuvant) single dose has been 
selected for further development by the Sponsor in a planned Phase 3 clinical study (EBSI-
CV-317-004). 
2 
STUDY OBJECTIVES AND PURPOSE 
2.1 
Primary Objectives 
• To assess the induction of anti-CHIKV neutralizing antibody responses following a 
single adjuvant dose of PXVX0317 as measured 21 days (Day 22) after vaccination.  
• To assess the induction of anti-CHIKV neutralizing antibody responses following a 
single adjuvant dose of PXVX0317 as measured 7 days (Day 8), 14 days (Day 15), 
and 56 days (Day 57) after vaccination.  
2.2 
Secondary Objective  
• To assess the safety of a single dose of PXVX0317 in healthy adults.  
                    

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2.3 
Exploratory Objectives 
• To obtain plasma and sera at Days 22 and 57 from subjects immunized with a single 
dose of PXVX0317 (40 µg CHIK VLP adjuvanted with 300 µg Alhydrogel) to 
support nonclinical studies.    
• To characterize the kinetics of anti-CHIKV IgM, IgG, and neutralizing responses 
following a single dose of PXVX0317 as measured 7, 14, 21, and 56 days (Days 8, 
15, 22, and 57) after vaccination. 
• To characterize T and B-cell responses following a single dose of PXVX0317 with 
collections of PBMCs 7, 14, 21, and 56 days (Days 8, 15, 22, and 57 respectively) 
after vaccination. 
3 
STUDY DESIGN 
3.1 
Study Description 
This is an open-label, single arm Phase 2 study in healthy adults 18 to 45 years of age. This 
study has a screening period of 30 days, a treatment and observation period from Day 1 to 
Day 22, and a follow-up period through Day 183. Subjects will receive CHIKV VLP at a 
dose of 40 µg in combination with 300 µg Alhydrogel on Day 1, have follow-up visits on 
Day 8, Day 15, and Day 22, with an additional plasmapheresis procedure and collection of 
serum on Day 22. A phone call follow-up visit will occur on Day 29, followed by a second 
plasmapheresis procedure and collection of serum at Day 57. A phone call follow-up visit to 
assess safety and concomitant medications will occur on Day 64. An EOS phone call follow-
up visit to assess safety and concomitant medications will occur on Day 183. 
3.1.1  Study Centers 
This is a single center study in the US.  
3.1.2 Number of Subject (Planned) 
Twenty-five subjects are targeted for enrollment.  
3.1.3 Estimated Study Duration 
The per subject estimated total study duration is 213 days. The screening window will be no 
greater than 30 days prior to Day 1 (administration of IP). Plasmapheresis will be performed 
on Day 22 and Day 57 with an EOS phone call on Day 183.  
                    

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3.3 
Description of Study Assessments 
The underlying subsections (Section 3.3.1 through Section 3.3.13) describe the planned study 
procedures and assessments. For the per visit timing of these procedures and assessments 
refer to Section 5.2 and the study Schedule of Events. Information on subject consent is 
described in Section 11.1. 
3.3.1 Review of Eligibility Criteria 
Review of inclusion and exclusion criteria should be completed, and subject eligibility 
confirmed prior to planned vaccination and plasmapheresis procedures. Refer to Section 4.1 
and Section 4.2 for criteria. 
3.3.2 Medical History and Demography 
Medical history information will be collected from subjects at the Screening Visit and 
confirmed at the Day 1 Visit (at baseline i.e., prior to IP administration) and will include (but 
not be limited to) demographic information (date of birth, race, ethnicity, and sex of subject), 
current and past medical conditions (including presence of joint pain), prior and concomitant 
medications (see Section 5.3) taken within 30 days of Screening Visit (or within 90 days for 
blood products, or within 6 months for immunosuppressive/immunomodulatory 
medications). 
3.3.3 Physical Examination 
A complete physical examination will be performed on subjects during the Screening Visit. 
The examination should include, general appearance, eyes-ears-nose-throat, head-neck, 
lungs-chest, heart, abdomen, musculoskeletal, lymph nodes, skin, extremities, and 
neurological assessment.  
A targeted physical exam may be performed on subjects at additional time points if indicated 
by AE, SAE, or Adverse Event of Special Interest (AESI) reports. 
3.3.4 Vital Signs 
Vital signs collected from subjects will include blood pressure, heart rate, respiratory rate, 
and temperature. The first set of screening vitals are to be collected and transcribed into the 
screening electronic Case Report Form (eCRF) for inclusion of the subject into the study. 
Repeat measurements on abnormal vital parameters are allowed twice for confirmation of 
eligibility to receive the vaccination. Vital signs will be taken prior to and after study vaccine 
administration and should be within normal limits prior to planned vaccination. 
Measurement of body weight, height for body mass index (BMI) calculations will be 
obtained at the Screening Visit. 
                    

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3.3.5 Laboratory Tests 
At the Screening Visit, blood samples will be collected for serum testing for HBsAg, HCV 
antibody, HIV-1/HIV-2 antigen/antibody (Ag/Ab), and CHIKV IgG antibodies, and urine 
will be collected for pregnancy testing for women of childbearing potential (CBP).   
For additional information on sample collection, processing, storage, and shipment refer to 
the study Laboratory Manual.  
3.3.6 Immunogenicity Sample 
Anti-CHIKV SNA levels will be assessed using a validated CHIKV-luc assay that measures 
neutralization titer of 80% (NT80). CHIKV IgM and IgG levels will be assessed by serum 
ELISA and PBMCs by assays performed on whole blood. Blood samples will be taken on 
Day 1 (prior to IP administration), Day 8, Day 15, Day 22, and Day 57 (or at Early 
Discontinuation/Withdrawal). For information on the immunogenicity assessment see 
Section 6.1.  
For additional information on sample collection, processing, storage, and shipment refer to 
the study Laboratory Manual. 
3.3.7 Pregnancy Testing and Contraception 
Female subjects of CBP will undergo a urine pregnancy test at the Screening Visit and prior 
to IP administration on Day 1, prior to plasmapheresis on Day 22 and Day 57, and at any 
Early Discontinuation Visit. The subject must have a negative urine pregnancy test on Day 1, 
prior to administration of IP, and prior to both plasmapheresis visits.  
Women of CBP must also use an acceptable method of contraception from prior to Day 1 
through the Day 183 EOS Visit. Acceptable methods include highly effective forms of 
contraception such as: hormonal contraceptives (e.g., implants, pills, patches) containing 
combined estrogen and progestogen, or progestogen-only initiated ≥30 days prior to dosing 
or IUD inserted ≥30 days prior to dosing or use of double barrier type of birth control (male 
condom with female diaphragm, male condom with cervical cap). The Investigator must 
confirm that contraception methods (e.g., hormonal contraceptive or intrauterine device) 
were initiated ≥30 days prior to Day 1 to be considered fully effective.  
The Investigator must report any pregnancies as described in Section 7.3.1. 
3.3.8 Investigational Product Administration 
Investigational Product is 0.8 mL in volume and administered by IM injection into the 
deltoid muscle with a field-formulated syringe attached to 25 gauge 1” (or 1.5”) needle, using 
universal precautions and sterile technique in accordance with General Best Practice 
Guidelines for Immunization: Best Practices Guidance of the Advisory Committee on 
Immunization Practices (ACIP) (27) per Table 1. 
                    

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Details on definition, evaluation, reporting periods and documentation are outlined in Section 
7. 
3.3.11 Unsolicited Adverse Events 
Unsolicited AEs (AEs not listed in the memory aid) will be collected from Day 1 through 28 
days post-vaccination (Day 29) (see Section 7.1.3). Adverse events related to plasmapheresis 
procedures will be collected at the Day 22 and Day 57 visit. Serious AEs and AEs that result 
in changes to the plasmapheresis procedure(s), such as early termination of collection, must 
be reported within 24 hours of awareness to the Medical Monitor (MM). 
Details on definition, evaluation, reporting periods and documentation are outlined in Section 
7. 
3.3.12 Serious Adverse Events and Adverse Events of Special Interest 
Serious AEs and AESI will be collected for all subjects from Day 1 through Day 183 EOS 
Visit (see Section 7.1.4 and Section 7.1.5). 
Details on definition, evaluation, reporting periods and documentation are outlined in Section 
7. 
3.3.13 Plasmapheresis Procedure  
 will be the designated apheresis site. 
Per the blood bank guidelines, plasmapheresis can be done once every 28 days. 
Plasmapheresis will be performed using either the
Plasmapheresis system 
while connected to the 
 data management system (preferred option) or the 
 
Blood Component Collection System while connected to 
 
Information Systems per their standard operating procedures (SOPs). 
Subjects will be advised to consume a well-balanced meal and a 12-ounce glass of a 
decaffeinated beverage prior to the procedure. The amount of plasma collected may range 
from ~600 to 900 mL (depending on donor weight) and the amount of red blood cell loss will 
be ~10 to 15 mL. Subject identity will be confirmed before the procedure begins. Prior to 
venipuncture, the designated phlebotomist will prepare each subject’s arm for phlebotomy by 
sterilizing the designated insertion site on the subject’s arm and by ensuring adequate venous 
access. Each subject should expect plasma drawing to take approximately 1 to 2 hours. 
Subjects will be monitored for any reactions or discomfort during and after the procedure. 
Subject tolerance to the anticoagulant must be monitored as well. 
3.4 
End of Study 
An individual subject is considered to have completed study participation after completion of 
the Day 183 visit and any required safety follow-up.  
                    

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4 
SELECTION AND WITHDRAWAL OF SUBJECTS 
4.1 
Subject Inclusion Criteria 
Subjects must meet all the following criteria to be enrolled: 
1. 
Able and willing to provide informed consent voluntarily signed by subject  
2. 
Any gender, 18 to 45 years of age (inclusive).   
3. 
Generally healthy, in the opinion of the Investigator, based on medical history, 
physical examination and screening laboratory assessments.  
 
4. 
Women who are either: 
i. 
Not of CBP: pre-menarche, anatomically sterile, or post-menopausal (defined 
as ≥12 months without menses). 
or: 
ii. 
Meeting all the below criteria: 
• Negative urine pregnancy test at screening visit and 
• Negative urine pregnancy test immediately prior to dosing at Day 1 and 
• Using an acceptable method of contraception (if female of CBP) for the 
duration of participation, such as:  
• Hormonal contraceptives (e.g., implants, pills, patches) initiated ≥30 days 
prior to dosing or 
• Intrauterine device (IUD) inserted ≥30 days prior to dosing or 
• Double barrier type of birth control (male condom with female diaphragm, 
male condom with cervical cap). 
4.2 
Subject Exclusion Criteria 
Subjects who meet any of the following criteria cannot be enrolled: 
1. 
Currently pregnant, breastfeeding, or planning to become pregnant during the 
study. 
2. 
Body Mass Index ≥35 kg/m2. 
3. 
Positive laboratory evidence of current infection with human immunodeficiency 
virus (HIV-1, HIV-2), hepatitis C virus (HCV) or hepatitis B virus (HBV). 
4. 
History of severe allergic reaction or anaphylaxis to any component of the IP. 
5. 
History of known congenital or acquired immunodeficiency that could impact 
response to vaccination (e.g., leukemia, lymphoma, generalized malignancy, 
functional or anatomic asplenia, alcoholic cirrhosis).  
                    

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6. 
Prior or anticipated receipt of immunomodulatory or immunosuppressive therapy 
from six months prior to screening through Day 64. 
7. 
Receipt or anticipated receipt of blood or blood-derived products from 90 days 
prior to screening through Day 64. 
8. 
Acute disease within the last 14 days (subjects with an acute mild febrile illness 
can be considered for a deferral of vaccination two weeks after the illness has 
resolved and treatment has been completed). 
9. 
Clinically significant cardiac, pulmonary, respiratory, rheumatologic, or other 
chronic disease, in the opinion of the Investigator. This may include chronic 
illness requiring hospitalization in the last one month prior to screening.  
10. Enrollment in an interventional study and/or receipt of another investigational 
product from 30 days prior to screening through the duration of study 
participation. 
11. Receipt or anticipated receipt of any vaccine from 30 days prior to screening 
through Day 64. 
12. Prior receipt of an investigational CHIKV vaccine/product. 
13. Detectable baseline anti-CHIKV IgG antibody as determined by ELISA.  
14. Any other condition that, in the opinion of the Investigator, could adversely 
impact the subject’s participation or the conduct of the study, creates an 
unacceptable risk to the subject, or may interfere with the conduct of the study or 
validity of the data. 
15. Restricted venous access that would prevent the collection of plasma and serum 
necessary for participation. 
16. Weight <110 pounds. 
4.3 
Withdrawal of Subjects 
4.3.1 Subject Consent Withdrawal 
All subjects can withdraw from participation in this study at any time, for any reason, 
specified or unspecified, and without penalty. The Investigator will ask (but cannot require) 
such subjects to provide the reason(s) for withdrawal of consent and to undergo an Early 
Withdrawal Visit. An individual is considered to undergo early withdrawal if they stop study 
participation before Day 183 EOS Visit.  
Safety follow-up for AEs should occur for all subjects. For information on safety follow-up 
for withdrawn subjects see Section 4.3.3.  
                    

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4.3.2 Investigator-Based Subject Withdrawal 
The Investigator may withdraw a subject from further participation in the study, at their 
discretion, if medically necessary or for reasons of noncompliance. The reason for 
withdrawal of any subject must be clearly documented on the study source documents and 
the appropriate eCRF. The Investigator is encouraged to consult the Sponsor prior to the 
withdrawal of any subject, except in the event of a medical emergency.  
The Investigator (and/or Sponsor) may withdraw a subject from the study for any of, but not 
limited to, the following reasons: 
• Noncompliance with the protocol. If the subject is non-compliant with protocol 
requirement, the issue should be discussed with the subject and, if not resolved, 
consideration given to withdrawing the subject. 
• Lost to follow-up; requires documentation of at least three unsuccessful attempts to 
contact subjects. Lost to follow-up will be determined after the date of the subject’s 
projected last visit. 
• Other reason(s) which, in the opinion of the Investigator, indicates that continued 
participation in the study is not in the best interest of the subject.  
Safety follow-up for AEs should occur for all subjects. For information on safety follow-up 
for withdrawn subjects see Section 4.3.3.  
4.3.3 Follow-up for Withdrawn Subjects 
Outreach will be made to ensure that subjects who are withdrawn, or who withdraw from the 
study, during the active observation or follow-up period will complete all safety and 
available assessments for the Early Withdrawal Visit as outlined in this protocol. The 
Investigator should inform the subject that these assessments are for their own well-being 
and, if possible, for study purposes. Additional information regarding ongoing AEs may be 
provided as a follow-up report.  
4.3.4 Documentation of Withdrawal/Discontinuation 
Reasons for withdrawal of individual subjects from the study prior to final protocol required 
visit and/or final safety follow-up are to be recorded on the CRF. The reason for withdrawal 
from the study will be recorded as one of the following: 
• Lost to Follow-up (Note: Requires documentation of at least three unsuccessful attempts 
to contact subjects, lost to follow-up will be determined after the date of the subject's 
projected last visit) 
• Adverse event 
• Pregnancy 
• Protocol deviation (that results in discontinuation) 
                    

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• Non-compliance  
• Physician (i.e., Investigator) decision     
• Other 
Safety follow-up for AEs should occur for all subjects, for information on safety follow-up 
for withdrawn subjects (see Section 4.3.3 Follow-up for Withdrawn Subjects). 
4.3.5 Subject Replacement   
Subjects who undergo Early Discontinuation or withdrawal of consent before receiving 
treatment or Day 22 plasmapheresis may be replaced at the Sponsor’s discretion. Subjects 
who undergo Early Discontinuation after Day 22 plasmapheresis will not be replaced.   
5 
TREATMENT OF SUBJECTS 
5.1 
Investigational Product(s) 
5.1.1 CHIKV VLP 
CHIKV VLP refers to the virus-like particle (VLP) component of PXVX0317 produced by 
transient transfection of human embryonic kidney (HEK) 293 cells with a DNA expression 
plasmid encoding Capsid (C) and E3, E2, 6K, and E1 proteins. After expression of the 
plasmid-encoded proteins, VLPs self-assemble and are released into the cell culture medium 
as ~70 nm particles. The 6K and E3 proteins have not been specifically detected in the VLPs. 
No replication-capable viral genetic material is incorporated into the VLPs. Virus-like 
particles are then concentrated from the cell supernatant and purified. After purification, the 
VLPs are diluted into a sucrose-containing aqueous buffer, sterile-filtered and filled into 
sterile single-dose glass vials to create the final CHIKV VLP drug product. The production 
process does not use animal-derived raw materials or antibiotics. Process residuals (including 
host cell and recombinant DNA, host cell protein, and Benzonase®) were assessed to be at 
acceptable levels. All excipients are generally regarded as safe (GRAS). 
The CHIKV VLP drug product is a sterile aqueous buffered solution filled into 3 mL single-
use glass vials with a 0.8 mL fill volume. The vial is sealed with a rubber stopper and an 
aluminum seal with a blue flip-off cap. The drug product is stored in a qualified, 
temperature-controlled freezer at ≤–70°C. See the Pharmacy Manual for additional 
information on vaccine storage and preparation. 
The composition of CHIKV VLP drug product (Lot Number 1-FIN-2949) is shown in Table 
2. 
                    

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The Principal Investigator (or designee) will be responsible for checking the number of 
vials/bottles and the condition of the vials/bottles received, and entering this information into 
the drug accountability records, and reporting the condition of shipment to the Sponsor. 
Investigational Product received in good condition will be automatically released for use 
upon confirmation of receipt as such; shipments received with any excursions/issues will be 
placed under quarantine by the site and released for use by the Sponsor following 
investigation. For additional information on IP shipments please refer to the study Pharmacy 
Manual.  
5.1.5 Storage Conditions 
PXVX0317 vials must be stored in a qualified, temperature-controlled freezer at ≤–70°C in a 
secured area until ready for use. The temperature in the storage area must be monitored by 
checking and recording current, maximum/minimum temperature readings inside the vaccine 
storage unit once each working day. Any excursions must be promptly reported to the 
Sponsor; product should be quarantined by the site and may be released for use by the 
Sponsor only after investigation and confirmation of continued stability.  
The recommended storage condition for the adjuvant is room temperature not to exceed 
30°C. Avoid freezing. 
Please refer to the Pharmacy Manual for additional details.  
5.1.6 Other Supplies  
The following supplies are supplied by the Sponsor for formulation and administration of 
study vaccine: 
1. 
3/10 mL BD Lo-Dose™ U-100 insulin syringe with 29 Gauge x 1/2 (BD Cat # 
324702)  
2. 
1 mL BD Luer-Lok™ Syringe sterile, single use polycarbonate (BD Cat # 
309628) 
3. 
25 Gauge BD™ Needle 1 in. single use, sterile (BD Cat # 305125) 
4. 
25 Gauge BD™ Needle 1 1/2 in. single use, sterile (BD Cat # 305127) 
Plasmapheresis kits will be supplied by the Community Blood Center of Greater Kansas 
City. 
5.1.7 Preparation 
1. 
0.03 mL Alhydrogel is added to a first CHIKV VLP vial (0.8 mL) and mixed by 
swirling (first dose vial). 
2. 
0.03 mL Alhydrogel is added to a second CHIKV VLP vial (0.8 mL) and mixed 
by swirling (second dose vial). 
3. 
Both vials are held at room temperature for 15 minutes. 
                    

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4. 
0.4 mL of CHIKV VLP is withdrawn from the first dose vial into a syringe, 
syringe plunger is pulled to 0.8 mL mark and then CHIKV VLP injected into the 
second dose vial. A total of 0.8 mL is then withdrawn from the second dose vial 
into syringe. 
All doses are prepared into Sponsor-provided syringes using sterile technique and all doses 
must be administered no later than 1 hour post thaw of CHIKV VLP. For further information 
on Study Vaccine, including secondary packaging, receipt, accountability, and detailed 
preparation instructions, please refer to the Pharmacy Manual. 
5.1.8 Drug Accountability 
The Investigator is responsible for maintaining accurate inventory records of IP. The 
Investigator (or designee) will inventory all IP shipments upon receipt. The Investigator or 
designee must ensure that all drug supplies are kept in a secure location in the site pharmacy 
in accordance with recommended storage conditions (Section 5.1.5). Inventory and ongoing 
record of test material supplies will be documented using the Drug Accountability Form 
provided. These records will be reviewed by representatives of the Sponsor and may be 
reviewed by regulatory agencies.  
5.2 
Study Procedures and Assessments by Visit 
The timing of the study procedures and assessment below are shown in the Schedule of 
Events and a description of each procedure and assessment is described in Section 3.3.   
5.2.1 Screening (Visit 1, within 30 days of Day 1) 
Eligible subjects will first undergo informed consent counseling. Once informed consent has 
been obtained, subjects will undergo a Screening Visit to ascertain their eligibility in this 
study within 30 days prior to Day 1. The Screening visit assessments will include: 
• Informed consent (Section 11.1) 
• Review of eligibility criteria (Section 3.3.1, Section 4.1, Section 4.2) 
• Medical history (including presence of joint pain) (Section 3.3.2) 
• Demographics (date of birth, race, ethnicity, and sex of subject) (Section 3.3.2) 
• Prior and current medications (Section 3.3.2, Section 5.3)   
• Vital signs (blood pressure, heart rate, respiratory rate, and temperature) as well as height 
and body weight (for BMI calculation) (Section 3.3.4) 
• Complete physical exam (general appearance, eyes-ears-nose-throat, head-neck, lungs-
chest, heart, abdomen, musculoskeletal, lymph nodes, skin, extremities, and neurological 
assessment) (Section 3.3.3)  
                    

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• Blood collection for laboratory viral marker testing (HBsAg, anti-HCV antibody, HIV-
1/HIV-2 Ag/Ab) (Section 3.3.5) 
• Blood collection for anti-CHIK IgG antibody (ELISA kit) testing 
• For women of CBP: urine sample for pregnancy test (Section 3.3.5, Section 3.3.7) 
5.2.1.1 
Re-Screening 
Re-screening may occur given the following circumstances:  
• If the participant has an acute febrile illness at the time of their scheduled enrollment, 
they may be re-screened 14 days after resolution of their acute illness  
• If the participant is asymptomatic but tests positive by reverse transcription polymerase 
chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-
CoV-2) they may be re-screened provided 14 days have elapsed since the participant 
tested RT-PCR positive for SARS-CoV-2, the participant continues to be asymptomatic, 
and the participant is otherwise eligible for enrollment 
• Participants who have received vaccines within 30 days of screening may be re-screened 
provided no additional doses are anticipated up to Day 64 
• Participants who have received blood products or investigational products from 
participation in another clinical study may be re-screened after the appropriate duration 
has passed (90 days for blood products; 30 days for investigational drugs)  
• Eligible subjects who are not able to be vaccinated within 30 days of their screening 
period may be re-screened 
Re-screened subjects must undergo all screening procedures again, including re-consenting 
and use of the same subject ID number. Subjects may be re-screened one time only. Re-
screening is not otherwise permitted. 
5.2.2 Day 1 (Baseline and Administration of IP) Visit 2 
The following will take place during the visit and prior to IP administration: 
• Re-verification of eligibility criteria 
• Review medical history 
• Directed physical exam (as needed, if indicated by medical history) 
• Review prior and concomitant medications 
• Vital signs 
• For women of CBP: urine pregnancy test 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC (Section 3.3.6, Section 6.1) 
• IP administration (Section 3.3.8, Section 5.1) 
                    

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The following will take place during the visit and after IP administration: 
• In-clinic acute observation for 30 mins after injection but no more than 60 mins after 
injection (Section 3.3.9)   
• Vital signs 
• Memory aid, digital thermometer, and ruler distribution, set-up, and training (Section 
3.3.10)  
• Solicited AE, unsolicited AE, SAE, and AESI (Sections 3.3.10 - 3.3.12, Section 7) 
evaluation 
• Review concomitant medications 
5.2.3 Day 8 (+3) Visit 3 
• Review memory aid 
• Solicited AE, unsolicited AE, SAE, and AESI evaluation 
• Review concomitant medications 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC  
• Directed physical exam (as needed) 
5.2.4 Day 15 (±2) Visit 4 
• Unsolicited AE, SAE, and AESI evaluation 
• Review concomitant medications 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC  
• Directed physical exam (as needed) 
5.2.5 Day 22 (+5) Plasmapheresis Visit 5 
• Review of inclusion/exclusion criteria  
• For women of CBP: urine pregnancy test 
• Unsolicited AE, SAE, and AESI evaluation 
• Review concomitant medications 
• Directed physical exam (as needed) 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC 
• Serum collection for nonclinical studies 
• Plasmapheresis procedure performed at blood bank 
• AE follow-up 30 minutes post plasmapheresis 
                    

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5.2.6 Day 29 (-1/+5) Telephone Contact for Visit 6 
• Unsolicited AE, SAE and AESI evaluation 
• Review concomitant medications  
5.2.7 Day 57 (+5) Plasmapheresis Visit 7  
• Review of inclusion/exclusion criteria  
• For women of CBP: urine pregnancy test 
• SAE and AESI evaluation 
• Review concomitant medications (only if associated with SAE/AESI) 
• Directed physical exam (as needed) 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC 
• Serum collection for nonclinical studies 
• Plasmapheresis procedure performed at blood bank 
• AE follow-up 30 minutes post plasmapheresis 
5.2.8 Day 64 (-1/+5d) Telephone Contact for Visit 8 
• SAE and AESI evaluation 
• Review concomitant medications (only if associated with SAE or AESI) 
5.2.9 Day 183 (-14/+7d) Telephone Contact for Visit 9 End of Study 
• SAE and AESI evaluation 
• Review concomitant medications (only if associated with SAE or AESI) 
5.2.10 Early Discontinuation/Withdrawal Visit 
All subjects who discontinue study participation before the Day 57 visit will be requested to 
undergo an Early Discontinuation/Withdrawal Visit. The following will be conducted: 
• Review AEs, AESI and SAEs 
• Review concomitant medications associated with new or ongoing AEs and any AESIs 
or SAEs 
• Blood collection for anti-CHIKV SNA, ELISA, PBMC 
• For women of CBP: urine pregnancy test 
If the visit occurs within 7 days after study vaccine administration, the following will also be 
conducted: 
                    

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a. Review of the memory aid 
b. AE (solicited) evaluation 
5.2.11 Unscheduled Visits 
Any study procedure, excluding vaccination or plasmapheresis, may be conducted at an 
Unscheduled Visit as needed and recorded on the Unscheduled Visit eCRF. Examples 
include repeat specimen collection and additional safety follow-up for an AE/SAE/AESI.  
5.2.12 COVID-19 Related Considerations 
Emergent will monitor the situation related to the COVID-19 pandemic to ensure that 
potential risks to study participants and staff are mitigated. The following strategies will be 
implemented: 
i. 
The conduct of the study will be in accordance with state and local travel 
limitations/restrictions. 
ii. 
Study staff at the plasma center will take appropriate precautions to protect study 
participants. 
iii. 
Safety assessments will be performed by phone call when appropriate. 
iv. 
If travel restrictions or COVID-19 related illness impact the conduct of the study, 
specific measures will be taken to mitigate risk to study staff and participants and 
monitor protocol deviations due to COVID-19 illness and/or COVID-19 control 
measures. 
5.3 
Prior and Concomitant Medications 
At the Screening Visit, the details of prior and concomitant medication usage will be 
collected (through 30 days prior to screening, or 90 days prior for blood products, or within 6 
months for immunosuppressive/immunomodulatory medications). Concomitant medications 
will be collected at each on site visit or by phone interview (or early discontinuation/ 
withdrawal). The details of all concomitant medications including those associated with 
solicited AEs and unsolicited AEs will be collected through Day 29. Concomitant 
medications associated with a SAEs and AESI will be collected through the end of the study. 
5.3.1 Required Concomitant Medications 
Not applicable.  
5.4 
Procedures for Monitoring Subject Compliance 
All subjects will be administered the IP by study staff. Compliance with study protocol and 
procedures will be monitored on an ongoing basis by study staff.  
                    

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6 
IMMUNOGENICITY ASSESSMENT 
6.1 
Immunogenicity Analysis 
To the extent possible and practicable, serum and plasma samples will be utilized to 
understand antibody-mediated mechanisms of protection elicited by vaccination with CHIKV 
VLP. 
The immunogenicity analysis will be performed using a high-throughput in vitro infectivity 
assay developed by the Sponsor for assessing titers of neutralizing antibodies against CHIKV 
in serum samples. The assay is based on using a modified version CHIKV that expresses 
luciferase (CHIKV-luc) and measures the reduction of luciferase activity in infected cultures 
of Vero cells following treatment of virus with test serum. Using the CHIKV-luc assay, 
antibody neutralization titers can be determined via characterization of reductions of 
luciferase activity in the presence of immune serum. The quantitation of reporter gene 
expression, a correlate of the level of virus infection of cells, is determined by detection of 
luciferase in assay wells using a micro-plate luminometer. The CHIKV neutralizing antibody 
titre 80 (NT80) is the reciprocal of the serum dilution that provides 80% protection of Vero 
cells from CHIKV-luc infection or an 80% reduction of luciferase activity compared to virus 
only control. Additionally, neutralization analyses may include fractionated antibody 
subtypes and/or F(ab)/F(ab)2 products. Antibody responses, including IgM and IgG isotypes 
will also be assessed and quantified with a commercial anti-CHIKV ELISA test.   
The IgG and IgM antibody levels specific to CHIKV on days 1, 8, 15, 22, and 57 will be 
assessed by ELISA. Human serum samples from each timepoint will be tested using InBios 
Anti-CHIKV IgM/IgG ELISA Enzyme Immunoassays. These kits are ELISAs, where a 
capture antibody specific for total human IgG or IgM is coated onto polystyrene plates. 
Human serum samples are added, and any IgG or IgM present in the sample becomes 
immobilized on the plate. An antigen consisting of the chikungunya virus E1/E2 
glycoproteins is then added to the plate. Any anti-CHIKV E1/E2 antibodies present in the 
human serum samples will bind to the antigen and immobilize it to the plate. Next, a 
horseradish peroxidase (HRP)-conjugated anti-CHIKV E1/E2 antibody is added, which binds 
to any immobilized antigen in the wells. TMB (3,3',5,5'-tetramethylbenzidine) is used to 
develop the plate, and absorbance is read on a spectrophotometer at 450 nm. A calibrator 
control is included with the kit to establish a positive/negative cut-off absorbance. The 
reportable value, the Immune Status Ratio (ISR) value, is calculated by dividing the mean 
optical density (OD) of the test sample (for IgG or IgM) by the mean OD of the calibrator.  
Peripheral blood mononuclear cells will be collected for analysis of cell-mediated immunity. 
CHIKV antigen-specific B and T cell subsets will be identified and characterized by 
evaluating cytokine and antibody secretion using ELISpot and flow cytometry assays. The 
cell mediated immune response will be linked to previously determined antibody levels to 
define a mechanistic model for humoral response.  
                    

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7 
SAFETY ASSESSMENTS AND REPORTING 
7.1 
Definitions 
7.1.1 Adverse Event 
An AE is any untoward medical occurrence in a clinical study subject administered a 
pharmaceutical product or intervention regardless of its causal relationship to the study 
treatment. An AE can therefore be any unfavorable and unintended sign (including an 
abnormal laboratory finding, for example), symptom, or disease temporally associated with 
the use of a medicinal product/intervention, whether or not considered related to the 
medicinal product/intervention. 
Note: A diagnosis should be preferentially captured as an AE term and signs and symptoms 
should be captured only in the absence of a unifying diagnosis. If there are multiple 
diagnoses, then all diagnoses should be captured. The worsening of an existing sign, 
symptom or disease is also considered to be an AE. An abnormal laboratory finding deemed 
by the Principal Investigator as not clinically significant (NCS) will not be captured as an 
AE, but an abnormal laboratory finding that worsens after dosing with the study drug, from 
not clinically significant to clinically significant (CS), is considered an AE. Surgical 
procedures are not AEs. They are the action taken to treat a medical condition. Interventions 
that were planned prior to study entry for medical conditions that started prior to study entry 
but did not worsen during the clinical study are not reported as AEs. 
7.1.2 Solicited Adverse Event 
A solicited AE is a protocol-specified AE about which the Investigator (or designee) 
proactively asks the subjects about event occurrence. A reactogenicity event may be 
considered as a solicited AE per discretion of the Investigator (as described below in Section 
7.1.2.1). 
7.1.2.1 
Reactogenicity 
Reactogenicity (solicited systemic and injection site reactions) will be assessed by the 
subjects using paper memory aids. Information will be solicited on the following injection 
site reactions: pain, redness, and swelling. In addition, information will be solicited for AEs, 
on the following systemic reactions: temperature increases (oral) ≥38°C (≥100.4°F), chills, 
fatigue, headache, myalgia, arthralgia, and nausea.   
If injection site or systemic reactions continue beyond seven days post-vaccination, these will 
be recorded in the Electronic Data Capture (EDC) as unsolicited AEs. For any type of 
reactogenicity persisting two weeks or more, the Investigator (or designee) will evaluate the 
reaction at the next scheduled visit and/or determine based on the nature and severity if a 
more immediate unscheduled follow-up visit is required to fully assess the reaction.  
                    

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7.1.3 Unsolicited Adverse Event 
An unsolicited AE is an AE that is spontaneously reported by the subject or discovered by 
the Investigator.  
7.1.4 Adverse Event of Special Interest 
New onset or worsening arthralgia that is medically attended will be included as an AESI. 
The occurrence of new onset or worsening arthralgia that is medically attended will be 
monitored throughout the study for all subjects. Medically attended visits include hospital, 
emergency room, urgent care clinic, or other visits to or from medical personnel. 
7.1.5 Serious Adverse Event 
An SAE is any untoward medical occurrence that at any dose: results in death, is life 
threatening, requires inpatient hospitalization or prolongation of existing hospitalization, 
results in persistent or significant disability/incapacity, or is a congenital anomaly or birth 
defect.  
Important medical events which may not result in death, be life threatening, or require 
hospitalization may be considered a SAE when, based upon appropriate medical judgment, 
they may jeopardize the patient or subject and may require medical or surgical intervention to 
prevent one of the outcomes listed in this definition. 
Note: Death is an outcome and not an event. The condition leading to death is the event. If 
no other information regarding the cause of death is available, the event will be considered 
“Unspecified AE”. Overnight stays at hospital/clinic that occurs during a study for social 
reasons (e.g., transportation difficulties, respite care) is not considered to be a hospitalization 
event. 
7.1.6 Suspected Unexpected Serious Adverse Reaction 
Suspected Unexpected Serious Adverse Reaction (SUSAR) is the term used to refer to an AE 
that occurs in a clinical study subject, which is assessed by the Sponsor and or study 
Investigator as being unexpected, serious and as having a reasonable possibility of a causal 
relationship (Section 7.1.8) with the study drug.   
7.1.7 Severity of Adverse Events 
The Investigator will grade all AEs for severity. Adverse events listed in the Grading Scale in 
Appendix II will be graded according to the criteria in the table. Adverse events not listed in 
the Grading Scale will be graded as follows: 
• Mild (Grade 1): No interference with activity 
• Moderate (Grade 2): Some interference with activity 
• Severe (Grade 3): Significant; prevents daily activity 
                    

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• Potentially Life-Threatening (Grade 4): As determined by emergency room visit or 
hospitalization 
For the study Grading Scale see Appendix II.  
7.1.8 Causality of Adverse Events  
The Investigator is responsible for the assessment of the causality of an AE and Sponsor’s 
Medical Monitor will also assess SAE causality, independent of the Investigator.    
The following guidelines are provided for this assessment:   
• Unrelated: No relationship between the IP and the reported event. 
• Possibly related: The event follows a reasonable temporal sequence from the time of 
administration of IP and/or follows a known response pattern to the IP but could also 
have been produced by other factors. 
• Probably related: A reasonable temporal sequence of the event with administration 
of IP exists and based on the known response to the IP, known or previously reported 
adverse reactions to the IP or similar products, or in the Investigator’s (or designee) 
clinical judgment the association of the event with the IP seems likely. 
If the relationship between the AE and the IP is determined to be “possible” or “probable”, 
the event will be considered “related” to the IP. 
7.2 
Eliciting Adverse Events 
Adverse events reported spontaneously by the subject in response to an open question from 
the Principal Investigator (or designee) or revealed by observation (e.g., during physical 
exam) will be recorded by the Principal Investigator (or designee) on the AE eCRF. Study 
subjects will be provided with a 24-hour telephone number to contact study personnel in case 
of an untoward reaction. 
7.3 
Reporting Requirements for Immediately Reportable Events 
7.3.1 Principal Investigator’s Reporting Requirements 
The following events must be reported within 24 hours of awareness by the Principal 
Investigator (or designee) to Sponsor’s Medical Monitor and Global Pharmacovigilance 
Department (Global PV):   
• Any SAE regardless of causal association with the IP.  
• Any AESI regardless of causal association with the IP. 
• Confirmed pregnancy of female subjects.  
The appropriate form(s) (listed below) will be completed and sent by email to the following 
address:  
                    

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Emergent BioSolutions Inc. 
Email: 
    
Telephone (toll free): 
 
For SAE/AESI, the “Serious Adverse Event/Adverse Event of Special Interest Report Form” 
will be completed (abbreviated hereafter as “SAE/AESI Report Form”). The SAE/AESI 
Report Form is not the same as the AE eCRF. Supporting documentation that may be 
emailed to accompany the form(s) can include source documentation or medical records 
(e.g., discharge summary for hospitalizations, lab reports) which support a diagnosis. 
Participant identifiers (e.g., name, address, telephone number, social security number, 
medical record number, or hospital/laboratory number) must be redacted from the source 
documentation. All SAEs that are unexpected (e.g., adverse drug reactions) must be reported 
to the Institutional Review Board (IRB) by the Investigator (or designee) as required by ICH 
GCP E6. 
If a subject becomes pregnant during a study, the Sponsor will be notified. All pregnancies 
where conception occurred after first exposure to the IP through the EOS visit are to be 
followed to outcome (e.g., delivery, spontaneous/elective/therapeutic abortion), including 
after the study is completed and even if the participant is withdrawn from the study. If a 
pregnancy results in an abnormal outcome that the reporting health care professional 
considers might be due to the study drug, then the guidelines for expedited reporting of 
serious, unexpected adverse drug reactions (SUSAR) should be followed (see Section 7.3.2). 
Any pregnancy that occurs during study participation must be reported using clinical study 
pregnancy forms (“Pregnancy Notification Form” and “Pregnancy Follow-up Form”). To 
ensure subject safety, each pregnancy must be reported to the Sponsor within 24 hours of 
learning of its occurrence. The pregnancy must be followed up to determine outcome 
(including premature termination) and status of mother and child. Pregnancy complications 
and elective terminations for medical reasons must be reported as an AE or SAE. 
Spontaneous abortions must be reported as an SAE. 
Any SAE occurring in association with a pregnancy brought to the Investigator’s attention 
during or after the subject has completed the study and considered by the Investigator as 
possibly related to the study treatment, must be promptly reported to the Sponsor. 
 
The Investigator is responsible to notify their IRB according to their policy.  
7.3.2 Sponsor’s Reporting Requirements 
A SUSAR is a suspected adverse reaction that is both serious and unexpected (Section 7.1.6). 
As specified in 21 Code of Federal Regulations (CFR) 312.32, SUSARs will be reported by 
                    

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the Sponsor of the Investigational New Drug Application (IND) to the FDA and to all 
participating Principal Investigators in an IND safety report as soon as possible, no later than 
15 calendar days after the Sponsor becomes aware of the suspected adverse reaction (21 CFR 
312.32(c)(1)).  
In addition, any unexpected fatal or life-threatening suspected adverse reaction will be 
reported to FDA no later than seven calendar days after the Sponsor’s initial receipt of the 
information (21 CFR 312.32(c)(2)). 
7.4 
Reporting of Other Information - Unanticipated Problems 
As outlined by the Office for Human Research Protection (OHRP), unanticipated problems 
must be reported to the IRB according to the requirements of 45 CFR Part 46. Unanticipated 
problems are considered to include any incident, experience, or outcome that meets ALL the 
following criteria: 
• Unexpected (in terms of nature, severity, or frequency) given: 
• Procedures that are described in the study-related documents, such as the IRB 
approved research protocol and informed consent document. 
• The characteristics of the subject population being entered into the study. 
• Related or possibly related to participation in the study which means there is a 
reasonable possibility that the incident, experience, or outcome may have been caused 
by the sample collection. 
• Suggests that the study places subjects or others at a greater risk of harm (including 
physical, psychological, economic, or social harm) than was previously known or 
recognized. 
An incidence, experience, or outcome that meets the three criteria above generally will 
warrant consideration of substantive changes in the study or informed consent 
process/document or other corrective actions to protect the safety, welfare, or rights of 
subjects or others. Only a small subset of AEs occurring in human subjects participating in a 
clinical study will meet these three criteria for an unanticipated problem. There are other 
types of incidents, experiences, and outcomes that occur during the conduct of clinical study 
that represent unanticipated problems but are not considered AEs. For example, some 
unanticipated problems involve social or economic harm instead of the physical or 
psychological harm associated with AEs. In other cases, unanticipated problems place 
subjects or others at increased risk of harm, but no harm occurs. 
The Investigator should promptly notify the IRB when an unanticipated problem involving 
risks to subjects or others is identified. Also, the Investigator should notify the Sponsor of 
unanticipated problem(s). 
                    

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7.5 
Follow-up of Adverse Events 
All AEs/SAEs/AESI will be followed until resolution, stabilization, or up to 30 days after the 
last study visit. 
7.5.1 Follow-up of Nonserious Adverse Events 
Nonserious AEs that are identified during the 28-day post-vaccination period and still 
ongoing on the last scheduled visit must be recorded on the AE eCRF with the current status 
noted. All nonserious events that are ongoing at this time will be recorded as “Not 
Recovered/Not Resolved” on the AE eCRF. The status of ongoing, previously reported AEs 
will be subject to active follow-up. 
7.5.2 Follow-up of Serious Adverse Events or Adverse Events of Special Interest 
This study requires that participants be monitored for SAE/AESI up through the Day 183 
EOS Visit. From Day 1 (Visit 2), confirmed SAEs and confirmed AESI will be recorded on 
the AE eCRF. All SAEs that are ongoing at the time of Day 183/ Early Withdrawal visits will 
have final outcome recorded as “Not Recovered/Not Resolved”. 
The Investigator will provide or arrange appropriate care for participants for whom SAEs or 
potential AESI are reported. Withdrawal/discontinuation of subjects from the study to treat 
SAEs/AESI are at the discretion of the Investigator.  
All SAEs/AESI will be followed by the Principal Investigator (or designee) until one or the 
other condition is met: 
• The SAE is resolved or stable if condition is expected to remain chronic 
• The participant is referred to a specialist or other physician for treatment and follow-
up. The Principal Investigator (or designee) will follow the subject's condition even if 
the subject is seen by another physician, to obtain information about the diagnosis and 
outcome and any treatments and medications administered for the event. 
The following will be considered acceptable reasons for discontinuation of follow-up of 
ongoing SAEs: 
• Subject withdraws consent.  
• Subject is referred to appropriate long-term medical care. 
• Subject is considered lost to follow-up. 
It is expected that the clinical site will obtain supporting medical records from appropriate 
physicians and record and/or upload this information on the SAE Report Form within the AE 
eCRF. Additional information received related to any SAE must be added to the SAE Report 
Form within the AE CRF or forwarded to the Emergent Global PV Department within 24 
hours of awareness (Section 7.3.1). 
                    

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8 
STATISTICAL CONSIDERATIONS 
8.1 
Sample Size Determinations 
The sample size is based on practical, rather than statistical, considerations. Twenty-five 
subjects will provide adequate plasma and serum for future non-clinical purposes.  
8.2 
Analysis Populations 
Analysis will be based on the following study populations: 
Exposed Population: All subjects who receive IP. 
Safety Population: All subjects in the exposed population who provide safety assessment 
data.  This generally includes anyone who was not lost to follow-up at Day 1 as they will be 
at risk for reporting an SAE.  
Modified Intent-to-Treat (mITT) Population: All subjects who are vaccinated and have at 
least one post-injection anti-CHIKV SNA NT80 result.   
8.3 
Study Endpoints 
8.3.1 Primary Endpoints 
• Anti-CHIKV SNA seroresponse rate and associated 95% confidence interval (CI) at 
Day 22. 
• Anti-CHIKV SNA GMT and associated 95% CIs at Day 22. 
• Anti-CHIKV SNA seroresponse rate and anti-CHIKV SNA GMTs with associated 
95% CIs at Days 8, 15, and 57. 
• Anti-CHIKV ELISA IgG and IgM GMTs with associated 95% CIs at Days 8, 15, 22, 
and 57. 
• Geometric mean fold increase (GMFI) in anti-CHIK SNA titer from Day 1 to 
subsequent collection time points.  
• Geometric mean fold increase (GMFI) in anti-CHIK ELISA IgG and IgM from Day 1 
to subsequent collection time points.  
• Number and percentage of subjects with an anti-CHIKV SNA titer ≥15, 40, 60, 80, 
100, 160, 640, and 4-fold rise over baseline thresholds.  
8.3.2 Secondary Endpoints 
• Incidence of solicited AEs through Day 8. 
• Incidence of unsolicited AEs through Day 29. 
                    

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• Incidence of AESIs and SAEs through end of the study. 
8.3.3 Exploratory Endpoints  
The kinetics of the anti-CHIKV immune responses (via ELISA and neutralizing assay) will 
be characterized using the responses over time described under the primary and secondary 
endpoints. The exploratory endpoints (both categorical and continuous) for the T- and B-cell 
responses from PBMC samples will be described using descriptive statistics. 
8.4 
Handling Missing Data 
Subjects with missing immunogenicity data at Days 8, 15, 22 or 57 will be excluded from the 
corresponding analysis; missing immunogenicity data will not be imputed. CHIKV-luc assay 
anti-CHIKV SNA NT80 values or ELISA values below the lower limit of quantitation 
(LLOQ) will be replaced by LLOQ/2 in the immunogenicity analyses. Imputation rules for 
partial or missing dates will be described in the study statistical analysis plan (SAP). 
8.5 
Analysis of Disposition, Demographic and Baseline Characteristics 
Disposition will be summarized for all subjects. Demographic and baseline characteristics 
including age, sex, race, ethnicity, BMI, will be tabulated for the safety and mITT 
populations. Continuous endpoints will be summarized by descriptive statistics; categorical 
endpoints will be summarized by the number of subjects, frequency counts and percentages. 
Medical history will be coded to System Organ Class (SOC) and preferred term (PT) using 
the MedDRA dictionary and summarized by treatment group for the randomized population. 
Protocol deviations will be categorized as important or not important and evaluated for 
exclusion of data from analyses. Protocol deviations will be presented for the exposed 
population. 
8.6 
Immunogenicity Analysis 
Summary statistics for immunogenicity results by scheduled visit will be provided for the 
mITT, unless otherwise specified. In the analyses of the CHIKV-luc assay data and ELISA 
data as continuous variables, anti-CHIKV SNA NT80 values will be logarithmically 
transformed (base10), and the GMTs and associated 95% CI for each treatment group will be 
computed by exponentiating the corresponding log-transformed means and two-sided 95% 
CIs. Geometric mean fold increase will also be displayed by post-vaccination scheduled visit. 
Proportions of subjects with CHIKV-luc assay anti-CHIKV SNA NT80 ≥40 seroresponse rate 
and secondary response rates at other thresholds (e.g., 15, 60, 80, 100, 160, 640, 4-fold rise 
over baseline) will be reported with associated two-sided 95% Wilson method CIs by 
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Reverse cumulative distribution plots of CHIKV-luc assay anti-CHIKV SNA NT80 versus 
proportion of subjects will be generated by scheduled visit. Geometric mean titer will also be 
plotted over time. 
8.7 
Safety Analysis 
The safety of PXVX0317 in healthy adult subjects will be evaluated using solicited AEs 
occurring from IP administration on Day 1 until Day 8 and unsolicited AEs through Day 29, 
AESI and SAEs though Day 183 EOS Visit, and vital signs. Solicited AEs include local (i.e., 
pain, redness, and swelling) and systemic reactions (i.e., fever, chills, fatigue, headache, 
myalgia, arthralgia, and nausea). 
8.7.1 Exposure 
The frequencies and percentages of subjects treated will be summarized for the safety 
population. 
All safety analyses will be based on the safety population. 
8.7.2 Adverse Events 
Adverse events will be coded to SOC and PT using the MedDRA dictionary. Solicited AEs, 
unsolicited AEs, AESIs, and SAEs will be summarized separately by maximum severity for 
the safety population. 
8.7.2.1 
Solicited Adverse Events 
With the exception of redness and swelling, all solicited AEs will be summarized according 
to severity grading scales defined in Section 7.1.7 from “mild” to “potentially life-
threatening.” 
Solicited AEs will be recorded daily until 7 days post-injection (Day 8) using a memory aid. 
The analyses of solicited AEs will be performed by maximum severity and by treatment 
group. In addition, solicited AEs ongoing after 7 days post-injection (Day 8) will also be 
recorded as unsolicited AEs. 
Frequencies and percentages of subjects experiencing each solicited AE will be presented by 
maximum severity. Summary tables showing the occurrence of any local or any systemic 
solicited AE overall and at each time point will also be presented. 
The severity of redness and swelling, recorded as diameters (mm), will be summarized 
according to categories based on the largest diameter linear measurement when the local 
reaction is present:  
• Grade 0/absent = 0–24 mm 
• Grade 1/mild= >24–50 mm 
• Grade 2/moderate= >50–100 mm 
                    

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• Grade 3/severe= >100 mm 
• Grade 4/potentially life threatening = necrosis or exfoliative dermatitis 
Refer to Appendix II. 
Events reported as not present (0 mm is entered) will be reported as Grade 0. 
The following summaries of solicited events will be performed: 
1. 
Solicited events by day post-injection for each event and for any event.  
2. 
Time of first onset of solicited AEs, for each event and any event. 
3. 
Solicited AEs by maximum event severity, for each event and for any event. 
4. 
Duration of solicited AEs, for each event and any event.  
Solicited AEs, occurrence of at least one event by category (local, systemic), will also be 
included.  
Only subjects with at least one observation (i.e., any non-missing values but excluding “Not 
done/unknown”) for the solicited AEs will be summarized.  
8.7.2.2 
Unsolicited AEs 
All the unsolicited AEs occurring during the proscribed collection period in the study will be 
recorded, regardless of their assessment of relatedness by the Investigator. 
The original verbatim terms used by Investigators to identify AEs in the eCRFs will be 
mapped to PT using the MedDRA dictionary. The unsolicited AEs will then be grouped by 
MedDRA PT into frequency tables according to SOC. All reported AEs, as well as AEs 
judged by the Investigator as at least possibly related to IP, will be summarized according to 
SOC and PT. When an unsolicited AE occurs more than once for a subject, the maximum 
severity and strongest relationship to treatment will be counted. 
Only treatment-emergent AEs will be summarized (i.e., excluding those after a subject has 
given informed consent, but before vaccination).  
Unsolicited AEs will be summarized by alphabetic SOC and descending PT as follows: 
• Any unsolicited AE  
• Related (“possibly” or “probably” related) unsolicited AEs 
• SAEs 
• Related (“possibly” or “probably” related) SAEs 
• AESI 
• Unsolicited AEs leading to withdrawal 
• Any AE leading to death 
Listings of all AEs will be provided by subject.  
                    

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Combined Solicited and Unsolicited AEs: Solicited AEs continuing beyond 7 days after 
vaccination will be coded by MedDRA and combined with the unsolicited AEs. A summary 
of subjects with all combined solicited and unsolicited AEs, by SOC and PT, will also be 
provided. 
8.7.3 Clinical Laboratory Data 
No clinical laboratory data will be collected in this study. 
8.7.4 Physical Examinations 
Physical examinations by body system include a complete examination at screening and 
directed examination at Day 1. Physical examination data will be listed. 
8.7.5 Vital Signs 
Vital signs including temperature, blood pressure, respiratory rate, and heart rate at screening 
and pre- and post-vaccination on Day 1 will be listed.  
8.7.6 Prior and Concomitant Medications 
Prior and concomitant medications will be coded to preferred drug name using the WHO 
DRUG dictionary and summarized for the safety population. 
8.7.7 Other Safety Variables 
None. 
8.7.8 Subgroup Analysis 
Analyses of the primary immunogenicity and safety endpoints will be summarized by sex 
and race. 
8.7.9 Interim Analysis 
No formal interim analysis is planned.  
9 
DATA HANDLING AND RECORD KEEPING 
9.1 
Source Documents and Access 
Source data are all information, original records of clinical findings, and observations in a 
clinical study necessary for the reconstruction and evaluation of the study. The source 
documentation requirements described below apply to all source documentation and study 
                    

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records in any form, including those maintained in the Institution’s Electronic Health Record 
system, if applicable. 
The Investigator/Institution will maintain adequate and accurate source documents and study 
records that include all pertinent information related to subjects’ participation in the study, 
including details but not limited to signed and dated notes on consenting, eligibility, medical 
history, study assessments, IP administration, AEs, concomitant medications, subject follow-
up information and other relevant observations. 
Source data should be attributable, legible, contemporaneous, original, accurate, and 
complete. Changes to source data should be traceable, should not obscure the original entry 
and should be explained if necessary (e.g., via an audit trail). 
The Investigator/Institution shall permit study-related monitoring, audits, IRB review, and 
regulatory inspection(s), providing direct access to source data/documents.  
Records from the study that identify the subject will be confidential except that they may be 
given to and inspected by Sponsor (or designee), the IRB, the FDA, European Medicines 
Agency (EMA) and other government agencies as appropriate and will not otherwise be 
released except as required by law. All information provided to the investigator by the 
Sponsor is to be considered confidential unless otherwise stated. 
9.2 
Data Management 
A validated, EDC system will be used during the study. Data management activities to be 
performed for the study will be described in detail in the Data Management Plan (DMP) 
documents.  
9.3 
Data Collection and Discrepancy Management 
Data collected during the study will be recorded in the eCRFs designed for this study. 
Investigational sites will have the responsibility for capturing and maintaining accurate eCRF 
data, records, and relevant source documentation, as well as conforming to procedures 
established by the Sponsor around system access/security and ensuring a data audit/edit trail 
for data corrections. All source documents will be verified by the study monitor for accuracy. 
Information from external sources such as laboratory data, images, etc. as defined in this 
protocol will be collected and maintained outside the EDC and reconciled with the eCRF 
data periodically (as applicable). As data are entered into the eCRF, automated edit checks 
will validate data. Additionally, manual reviews will be performed for data discrepancy by 
the monitor and queries will be generated into the EDC system. After clinical sites respond to 
queries and data corrections are made and reviewed by the monitor, the Investigator will 
review and electronically sign the CRF for each participant. The Sponsor will review data for 
accuracy, completeness, and consistency during the conduct of the study and prior to 
database lock. 
For further information on eCRFs, refer to the CRF Completion Guidelines. Details on data 
handling will be described in the DMP. 
                    

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9.4 
Laboratory Data 
No external laboratory data transfers will be done. Sites will manually enter results to 
HBsAg/HCV antibody/HIV-1/HIV-2/screening CHIKV IgG ELISA and pregnancy testing 
into applicable eCRFs. Anti-CHIKV SNA titer results and ELISA tests done after screening 
will be handled by Sponsor. 
9.5 
File Management at the Investigational Site 
The Investigator will ensure that the study site file is maintained in accordance with the ICH 
GCP Guideline and as required by applicable local regulations. The Investigator/Institution 
will take measures to prevent accidental or premature destruction of these documents. 
9.6 
Records Retention at the Investigational Site 
Per ICH guidelines, study documents will be retained for one of the following periods: 
• A period of at least two years after the date of the last approval of a marketing application 
in an ICH region until there are no pending or contemplated marketing applications. 
• A period of at least two years after Sponsor has notified the regulatory authority(ies) that 
clinical investigation with this product is discontinued. 
The Investigator must not dispose of any records relevant to this study without either (1) 
written permission from Sponsor or (2) provision of an opportunity for Sponsor to collect 
such records. The Investigator will be responsible to maintain adequate and accurate 
electronic or hard copy source documents of all observations and data generated during this 
study, including any data queries received from Sponsor (or designee). Such documentation 
is subject to inspection by Sponsor (or designee) and relevant regulatory agencies. If the 
Investigator withdraws from the study (e.g., due to relocation or retirement), all study-related 
records will be transferred to a mutually agreed upon designee within a Sponsor-specified 
timeframe. Notice of such transfer will be given to Sponsor in writing. 
9.7 
Deviations from the Protocol 
The Principal Investigator agrees to conduct the clinical study in compliance with the 
protocol agreed to by Sponsor and approved by the site’s IRB. 
A protocol deviation is defined as a site personnel or a study participant’s departure from the 
protocol requirements, whether inadvertent or planned. 
The Investigator or site staff may not deviate from the protocol, except, in rare 
circumstances, as necessary to eliminate immediate hazards to study participants. In such 
event, both Sponsor and IRB will be immediately notified.  
The occurrence of protocol deviations will be routinely monitored by for evaluation of 
Investigator compliance with the protocol, GCP, and regulatory requirements. The Sponsor 
will review all protocol deviations on an ongoing basis and will be responsible for 
                    

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determining if the deviation should be categorized as an Important Protocol Deviations 
(IPDs). Important Protocol Deviations may require additional documentation as requested by 
the Sponsor. 
Continued protocol deviations despite re-education of investigational site personnel, or 
persistent protocol deviations that are reportable to regulatory agencies may result in 
discontinued shipment of study drug and termination of further enrollment at the 
investigational site, or termination of the investigational site from the study. 
10 QUALITY CONTROL AND ASSURANCE 
10.1 
Monitoring 
The assigned clinical study monitor will verify eCRFs entries against source documentation 
at regular intervals throughout the study to verify adherence to the protocol; completeness, 
accuracy, and consistency of the data; and adherence to ICH-GCP Guidelines and local and 
federal regulations applicable to the conduct of the clinical study. The Principal Investigator 
must make source documentation accessible to the study monitor as needed to verify the 
information in the eCRFs. The Investigator agrees to meet with the study monitor at regular 
intervals to discuss study progress and ensure that any problems detected in the course of 
data monitoring are resolved appropriately. 
10.2 
Auditing 
Sponsor’s Quality Assurance Department (or designee) may conduct investigational site 
audits before study initiation, during the study, or after study completion, as documented in 
the Clinical Quality Oversight Plan. Audits will include, but are not limited to, review of 
drug supply, presence of required documents, informed consent process, and comparison of 
eCRFs with source documents. The Investigator agrees to participate in site audits and assist 
in the prompt resolution of any issues found during audits. 
Regulatory authorities or the IRB may inspect the investigational site during or after the 
study. The Investigator will cooperate with such inspections and will contact Sponsor 
immediately if such an inspection occurs. 
In the event the Investigator is contacted by a regulatory agency in relation to this study, the 
Investigator and investigational site staff must be available to respond to reasonable requests 
and inspection queries made during the inspection process. The Investigator must provide 
Sponsor with copies of all correspondence that may affect the review of the current study 
(e.g., Form FDA 483, inspectional observations, warning letters). Sponsor will provide any 
needed assistance in responding to regulatory inspections. 
11 ETHICS AND RESPONSIBILITY 
This study must be conducted in accordance with the ethical principles that have their origin 
in the Declaration of Helsinki and in compliance with the protocol, current ICH GCP 
                    

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Guideline, national regulatory authorities, and all other applicable local laws and regulatory 
requirements. Each investigational site will seek approval by an IRB according to regional 
requirements. The IRB will evaluate the ethical, scientific and medical appropriateness of the 
study. Further, in collecting and handling participant data and completing eCRFs, the 
Investigator and investigational site staff will take measures to ensure adequate care in 
protecting participant privacy. To this end, a subject identification number will be used to 
identify each participant. 
11.1 
Informed Consent 
The Investigator must obtain signed written informed consent from study participants prior to 
starting any study-related activities. All prospective subjects must sign and date an IRB-
approved Informed Consent Form (ICF). 
11.2 
Institutional Review Board (IRB) 
Before the start of the study, the IB, the protocol, proposed ICF(s), subject compensation (if 
any), Sponsor-approved study materials and advertisements, and any other written 
information to be provided to the subject, will be submitted to a properly constituted IRB for 
review. Sponsor must receive a copy of the written approval from the IRB for all of the 
above applicable documents prior to recruitment of subjects into the study and shipment of 
IP. 
The IRB must provide written approval for all amendments to any of the above documents 
prior to implementation of these amendments at the investigational site. The Investigator is 
obliged to report SAEs and AESI, as well as any unanticipated problems to the IRB in 
addition to other information as required by the IRB. 
The names (or title, if IRB procedures prohibit publishing of names) and associated 
backgrounds of the members of IRB (to assist in assuring that the board membership is 
properly constituted and operates according to 21 CFR part 56) will be given to the Sponsor 
prior to the start of the study along with a signed and dated statement stating that the protocol 
and ICF and, where applicable, any other document listed above, have been approved by 
them. 
All correspondence between the Investigator and the IRB will be available for review by the 
Sponsor (or designee), and the applicable regulatory authority(ies). 
11.3 
Compensation for Injury 
The Sponsor will adhere to local regulations and guidelines regarding clinical study 
compensation to subjects whose health is adversely affected by taking part in the study. The 
applicable policy for compensation for injury will be described in the ICF. 
                    

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11.4 
Subject Confidentiality 
The Investigator must ensure the anonymity of each subject is maintained at all times. 
Subjects should only be identified by their Subject Study ID number on the CRF or on any 
other study documents provided to Sponsor (or designee). Biospecimens should only be 
identified by sample numbers/codes as specified in the Laboratory Manual. Any documents 
that identify the subject should be kept in strict confidence by the study site.  
Based on ICH GCP guidelines and regulatory requirements, the Principal Investigator is 
required to allow authorized personnel of Sponsor (or designee), the IRB, and members of 
the appropriate regulatory authority(ies) to review subject’s files that are related to EBSI-CV-
317-010. Subjects must be informed that their records may be reviewed by Sponsor (or 
designee) the IRB and the appropriate regulatory authority(ies) through direct access to the 
subject’s original medical records. 
11.5 
Future Use of Stored Samples 
Any remnant (leftover) blood samples collected for the anti-CHIKV SNA analysis will be 
retained for future testing. Specimens will be identified by sample numbers/codes, thereby 
maintaining blinding while in storage. Subjects will be asked to consent to the future use of 
these samples as part of the informed consent process.  
Samples may be retained for at least two years after the last approval of a marketing 
application in an ICH region and until there are no pending or contemplated marketing 
applications in an ICH region or until at least two years have elapsed since the formal 
discontinuation of clinical development. 
12 ADMINISTRATIVE AND LEGAL REQUIREMENTS 
12.1 
Sponsorship 
This clinical study is sponsored by Emergent Travel Health Inc.
 
The manufacturer of PXVX0317 is Emergent 
BioSolutions Inc.  
12.2 
Protocol Amendments 
Protocol amendments will only be made by the Sponsor. In general, any change to the 
protocol must be made in the form of a formal amendment to the protocol and must be 
approved in writing by the Principal Investigator, the Sponsor, and the IRB prior to 
implementation. The Investigator must receive written IRB approval for all protocol 
amendments prior to implementing protocol amendments at the study site. The Investigator 
must send a copy of any IRB correspondence and all approval/disapproval letters from the 
IRB to the Sponsor. 
                    

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A protocol change intended to eliminate an apparent immediate hazard to participants will be 
implemented immediately, followed by IRB notification within five working days.  
The Sponsor will submit protocol amendments to the applicable regulatory authority(ies). 
12.3 
Clinical Study Registration 
For purposes of clinical study registration including reporting to ClinicalTrials.gov, the 
Sponsor is the responsible party and will provide information regarding this study in 
accordance with applicable regulations. 
12.4 
Publication Policy 
Following the completion of the study, the data may be considered for reporting at a 
scientific meeting or for publication in a scientific journal. In these cases, Sponsor will be 
responsible for these activities and may work with the Investigator(s) to determine how the 
manuscript is written and edited, the number and order of authors, the publication to which it 
will be submitted and other related issues. Sponsor has final approval authority over all such 
issues.  
Any proposed publication will be subject to review conditions and timelines agreed between 
Sponsor and the site Investigator and detailed in the agreements with these parties prior to the 
start of the study. The Sponsor will also post the results of the clinical study on 
ClinicalTrial.gov in a period no greater than 12 months from the completion of the study, 
defined as the time the final participant was examined or received an intervention for 
purposes of final collection of data for the primary outcome. 
Data are the property of the Sponsor and cannot be published without prior authorization 
from the Sponsor, but data and publication thereof will not be unduly withheld. 
All publication rights are delineated in the Clinical Trial Agreement. 
12.5 
Terminating the Study 
The Sponsor and/or the Principal Investigator may elect to terminate the study early as 
defined by the clinical study agreement. The Sponsor reserves the right to terminate the study 
at any time for clinical or administrative reasons. Any decision to voluntarily suspend or 
terminate a clinical study will be carefully reviewed and fully justified. The Sponsor will 
notify the FDA and the IRB of any suspension or termination and provide the justification. 
The Principal Investigator must notify the IRB in writing of the study’s completion or early 
termination. The Sponsor must receive a copy of the notification letter from the IRB 
indicating receipt of the completion or early termination letter. 
12.6 
Terminating the Study at an Individual Site 
A study site may be terminated from the study at the discretion of the Principal Investigator, 
Sponsor, or IRB. Sponsor may decide to replace a terminated site.  
                    

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13 REFERENCES 
1. 
EBSI. Investigator's Brochure Chikungunya virus-like particle (CHIKV VLP) vaccine 
(PXVX0317). 2021. 
2. 
Ross RW. The Newala epidemic. III. The virus: isolation, pathogenic properties and 
relationship to the epidemic. J Hyg (Lond). 1956;54(2):177-91. 
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