Open Label Extension Study to Assess the Safety and Long-Term Immunogenicity of ARCT-021

Study Overview
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Brief Summary
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This is an open-label study enrolling healthy adults that participated in Study ARCT-021-01 (the Parent Study). Participants will receive either a single injection of ARCT-021 or no injection and be followed for up to 365 days.

Detailed Description
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This is a phase 2a, open-label study enrolling up to 106 healthy adults that participated in Study ARCT-021-01 (the Parent Study). Participants will enter this study approximately 3 months after their final study visit in the Parent Study. Participants that received placebo in the Parent Study or who are seronegative for SARS-CoV-2 neutralizing antibodies at screening will receive a single dose of ARCT-021 and will be followed for 365 days. Participants that received two injections of ARCT-021 in the Parent Study will not receive any further injections of ARCT-021 and will be followed for 281 days.

Official Title
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A Phase 2a, Open Label Extension Study to Assess the Safety and Long-Term Immunogenicity of ARCT-021

Conditions
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SARS-CoV-2

Intervention / Treatment
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* Biological: ARCT-021


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals who: are able to give consent must have completed Study ARCT-021-01 agree to comply with all study visits and procedures Only for subjects that will receive ARCT-021 in this study: are healthy and medically stable are not planning to donate blood or plasma until 28 days after the last dose of ARCT-021. are willing to refrain from strenuous exercise/activity and alcohol for at least 72 hours prior to study visits and until 28 days after the last dose of ARCT-021. are willing to adhere to contraception requirements if sexually active and/or are of child-bearing potential Exclusion Criteria: Individuals who: are unable to comply with the study visits or procedures in Study ARCT-021-01 received placebo in the Parent Study and who are not willing to receive ARCT-021 in this study. Only for subjects that will receive ARCT-021 in this study: have or will receive any of the SARS CoV-2 or another experimental coronavirus during this study. have a diagnosis of new clinically significant abnormalities including but not limited to Respiratory disease requiring daily medications or oxygen currently or any treatment of respiratory disease exacerbations Significant heart conditions Significant neurological conditions Significant blood disorders Newly diagnosed autoimmune disease Major surgery have abnormal screening laboratory results have uncontrolled diabetes use of any prescription or over-the-counter medications within 7 days prior to vaccination have received immunoglobulins and/or any blood or blood products have a bleeding disorder have uncontrolled blood pressure have been treated with another investigational drug, biological agent, or device since completion of the Parent Study have received or plan to receive: A licensed, live vaccine within 4 weeks before or after study vaccination, or A licensed, inactivated vaccine within 2 weeks before or after study vaccination have traveled outside of Singapore within 30 days before the vaccination or plans to travel outside of Singapore within 60 days after vaccination. other restrictions may apply

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ARCT-021<br>Participants will receive a single dose of ARCT-021 on Day 1 | Biological: ARCT-021<br>* ARCT-021 single dose<br>|
| No Intervention: Long-term follow up from ARCT-021-01<br>Participants will not receive intervention but will be followed for safety. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentages of participants reporting solicited local adverse events | Adverse events reported daily in a diary that reflect common symptoms or findings at the injection site following vaccination | for 7 days following last study vaccine dose administration | 
| Percentages of participants reporting solicited systemic adverse events | Adverse events reported daily in a diary that reflect generalized symptoms following vaccination | for 7 days following last study vaccine dose administration | 
| Percentages of participants reporting adverse events | Spontaneously reported adverse events | for 28 days following last study vaccine dose administration | 
| Percentages of participants reporting serious adverse events | Unsolicited adverse events that meet the definition of serious | for 12 months following last study vaccine dose administration | 
| Percentages of participants reporting medically attended adverse events | Unsolicited adverse events that lead to healthcare provider visit | for 12 months following last study vaccine dose administration | 
| Percentages of participants reporting new onset of chronic disease | Unsolicited adverse events associated with new diagnosis of chronic disease | for 12 months following last study vaccine dose administration | 
| Percentages of participants with abnormal safety laboratory test values | Chemistry and hematology | for 28 days following last study vaccine dose administration | 
| Percentages of participants with abnormal vital sign assessments | Blood pressure, heart rate, respiratory rate | for 12 months following last study vaccine dose administration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| SARS-CoV-2 serum neutralizing antibody levels, expressed as GMTs | Neutralizing antibody response | for 12 months following last study vaccine dose administration for participants dosed in ARCT-021-02 study and for 15 months following last study vaccine dose administration for participants dose in the ARCT-021-01 study | 
| SARS-CoV-2 binding antibody levels, expressed as GMCs | Binding antibody response | for 12 months following last study vaccine dose administration for participants dosed in ARCT-021-02 study and for 15 months following last study vaccine dose administration for participants dose in the ARCT-021-01 study |