A Trial Evaluating the Safety and Effects of an RNA Vaccine ARCT-021 in Healthy Adults

NCT04668339 | Terminated Phase 2 Results DMC FDA Drug

• 1 other identifier: ARCT-021-04
• Study Type: interventional
• Target: 581
• Locations: 2 countries
• Sites: 15

Brief Summary

This is a Phase 2, randomized, placebo-controlled, and observer-blind study in healthy adults. The study will evaluate the safety, tolerability, and immunogenicity of the SARS-CoV-2 RNA vaccine candidate against COVID-19: As 2 doses (at two different dose levels), separated by 28 days or as 1 dose In adults 18 years of age and older

Conditions

Covid19; SARS-CoV Infection; Corona Virus Infection

Keywords

SARS-CoV-2 Vaccine; Coronavirus Virus Diseases; RNA COVID 19; COVID 19 Vaccine Arcturus; self amplifying RNA vaccine

Outcome Measures

Primary Outcomes (18)

• Percentage of Participants Reporting Solicited Local Adverse Events Within 7 Days Post Each Priming Vaccination

  Per prespecified analysis, solicited local adverse events were defined as pain, erythema, swelling, or injection site tenderness. Solicited adverse reactions were recorded by the participant in an eDiary. Per prespecified analysis, solicited adverse events were not evaluated for severity (such as, serious or non-serious). A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  For 7 days following each dose administration (Day 0 up to Day 7 for Vaccination 1 and Day 29 up to Day 35 for Vaccination 2)

• Percentage of Participants Reporting Solicited Local Adverse Events Within 7 Days Post Booster Vaccination

  Per prespecified analysis, solicited local adverse events were defined as pain, erythema, swelling, or injection site tenderness. Solicited adverse reactions were recorded by the participant in an eDiary. Per prespecified analysis, solicited adverse events were not evaluated for severity (such as, serious or non-serious). A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  For 7 days following each dose administration (Day 208 up to Day 215)

• Percentage of Participants Reporting Solicited Systemic Adverse Events Within 7 Days Post Each Priming Vaccination

  Per prespecified analysis, solicited systemic adverse events were defined as fever, headache, fatigue, myalgia, arthralgia, nausea, chills, diarrhea, dizziness, and vomiting. Per prespecified analysis, solicited adverse events were not evaluated for severity (such as, serious or non-serious). A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  For 7 days following each dose administration (Day 0 up to Day 7 for Vaccination 1 and Day 29 up to Day 35 for Vaccination 2)

• Percentage of Participants Reporting Solicited Systemic Adverse Events Within 7 Days Post Booster Vaccination

  Per prespecified analysis, solicited systemic adverse events were defined as fever, headache, fatigue, myalgia, arthralgia, nausea, chills, diarrhea, dizziness, and vomiting. Per prespecified analysis, solicited adverse events were not evaluated for severity (such as, serious or non-serious). A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  For 7 days post booster dose administration (Day 208 up to Day 215)

• Percentage of Participants Reporting Unsolicited Adverse Events Up to 28 Days Post Each Priming Vaccination

  An unsolicited AE was defined as any AE (serious and nonserious) occurring after administration of first dose of study vaccine and before the end of study. A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  28 days following each dose administration (Day 0 up to Day 28 for Vaccination 1 and Day 29 up to Day 56 for Vaccination 2)

• Percentage of Participants Reporting Unsolicited Adverse Events Up to 28 Days Post Booster Vaccination

  An unsolicited AE was defined as any AE (serious and nonserious) occurring after administration of first dose of study vaccine and before the end of study. A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  28 days following each dose administration (Day 208 up to 236 days)

• Percentage of Participants Reporting Treatment-Emergent Serious Adverse Events (SAE), Medically Attended Adverse Events (MAAE) and New Onset of Chronic Disease (NOCD) Post Each Priming Vaccination

  SAEs were defined as any event that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, resulted in a congenital anomaly or birth defect, or was an important medical event. An NOCD was defined as any AE that led to the new diagnosis of a chronic medical condition that was not present or suspected prior to enrollment. An MAAE was an AE that led to an unscheduled visit (including a telemedicine visit) to a healthcare practitioner. A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  Up to Day 207

• Percentage of Participants Reporting Treatment-emergent Serious Adverse Events, Medically Attended Adverse Events and New Onset of Chronic Disease Post Booster Vaccination

  SAEs were defined as any event that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, resulted in a congenital anomaly or birth defect, or was an important medical event. An NOCD was defined as an AE that led to the new diagnosis of a chronic medical condition that was not present or suspected prior to enrollment. An MAAE was an AE that led to an unscheduled visit (including a telemedicine visit) to a healthcare practitioner. A summary of all unsolicited adverse events and solicited adverse events regardless of causality is located in the Reported Adverse Events module.

  Day 208 to early termination (up to 396 days)

• Geometric Mean Titer (GMT) of Serum Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Neutralizing Antibodies Post Priming Vaccination

  Day 1

• GMT of SARS-CoV-2 Neutralizing Antibodies Post Priming Vaccination

  Day 56

• GMT of SARS-CoV-2 Neutralizing Antibodies Post Booster Vaccination

  Day 208

• GMT of SARS-CoV-2 Neutralizing Antibodies Post Booster Vaccination

  Day 236

• Geometric Mean Fold Rise (GMFR) in SARS-CoV-2 Neutralizing Antibody Titers Post Priming Vaccination

  GMFR is reported as a ratio to baseline (Day 0).

  Day 56

• Geometric Mean Fold Rise (GMFR) in SARS-CoV-2 Neutralizing Antibody Titers Post Booster Vaccination

  GMFR is reported as a ratio to baseline (Day 0).

  Day 208

• GMFR in SARS-CoV-2 Neutralizing Antibody Titers Post Booster Vaccination

  GMFR is reported as a ratio to baseline (Day 0).

  Day 236

• Percentages of Participants Achieving Greater Than or Equal to 2-fold and 4-fold Increase From Before Vaccination (Baseline) in SARS-CoV-2 Serum Neutralizing Antibody Levels at Day 56

  Baseline up to Day 56

• Percentages of Participants Achieving Greater Than or Equal to 2-fold and 4-fold Increase From Before Vaccination (Baseline) in SARS-CoV-2 Serum Neutralizing Antibody Levels at Day 208

  Baseline up to Day 208

• Percentages of Participants Achieving Greater Than or Equal to 2-fold and 4-fold Increase From Before Vaccination (Baseline) in SARS-CoV-2 Serum Neutralizing Antibody Levels at Day 236

  Baseline up to Day 236

Secondary Outcomes (4)

• Geometric Mean Concentration of SARS-CoV-2 Anti-S1, Anti-RBD, and Anti-N Binding Antibody Levels Post Priming Vaccination

  Days 0 and 56

• Geometric Mean Concentration of SARS-CoV-2 Anti-S1, Anti-RBD, and Anti-N Binding Antibody Levels Post Booster Vaccination

  Day 208 and 236

• Geometric Mean Fold Rise (GMFR) in SARS-CoV-2 Anti-S1, Anti-RBD, and Anti-N Binding Antibody Levels Before Vaccination to Day 56

  Day 56

• Percentage of Participants Achieving Greater Than or Equal to 2-fold and 4-fold Increase From Before Vaccination (Baseline) in SARS-CoV-2 Anti-S1, Anti-RBD, and Anti-N Binding Antibody Levels

  Day 56

Study Arms (8)

Study Group 1, Younger Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, one dose of Placebo (saline) on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 single dose priming; Biological: Randomized booster

Study Group 2, Younger Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, a second dose of ARCT-021 on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 two lower dose priming; Biological: Randomized booster

Study Group 3, Younger Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, a second dose of ARCT-021 on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 two higher dose priming; Biological: Randomized booster

Study Group 4, Younger Adult Participants

PLACEBO COMPARATOR

Participants will receive one of Placebo (Saline) on Day 0, one dose of Placebo on Day 28, and one dose of Placebo on Day 208

Biological: Placebo (two doses), priming; Biological: Placebo booster

Study Group 1, Older Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, one dose of Placebo (saline) on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 single dose priming; Biological: Randomized booster

Study Group 2, Older Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, a second dose of ARCT-021 on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 two lower dose priming; Biological: Randomized booster

Study Group 3, Older Adult Participants

EXPERIMENTAL

Participants will receive one dose of ARCT-021 on Day 0, a second dose of ARCT-021 on Day 28 and on Day 208 either one dose of ARCT-021 or one dose of placebo

Biological: ARCT-021 two higher dose priming; Biological: Randomized booster

Study Group 4, Older Adult Participants

PLACEBO COMPARATOR

Participants will receive one dose of Placebo (saline) on Day 0, a second dose of Placebo on Day 28 and a third dose of Placebo on Day 208

Biological: Placebo (two doses), priming; Biological: Placebo booster

Interventions

ARCT-021 single dose priming BIOLOGICAL

ARCT-021 higher dose (one dose) + placebo (one dose)

Study Group 1, Older Adult Participants; Study Group 1, Younger Adult Participants

ARCT-021 two lower dose priming BIOLOGICAL

ARCT-021 lower dose (two doses, Day 0 and Day 28)

Study Group 2, Older Adult Participants; Study Group 2, Younger Adult Participants

ARCT-021 two higher dose priming BIOLOGICAL

ARCT-021 higher dose (two doses, Day 0 and Day 28)

Study Group 3, Older Adult Participants; Study Group 3, Younger Adult Participants

Placebo (two doses), priming BIOLOGICAL

Placebo (two doses, Day 0 and Day 28)

Study Group 4, Older Adult Participants; Study Group 4, Younger Adult Participants

Randomized booster BIOLOGICAL

ARCT-021 (single dose) OR placebo, booster

Study Group 1, Older Adult Participants; Study Group 1, Younger Adult Participants; Study Group 2, Older Adult Participants; Study Group 2, Younger Adult Participants; Study Group 3, Older Adult Participants; Study Group 3, Younger Adult Participants

Placebo booster BIOLOGICAL

Placebo (single dose)

Study Group 4, Older Adult Participants; Study Group 4, Younger Adult Participants

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Individuals who:
• are able to provide consent
• agree to comply with all study visits and procedures
• are willing and able to adhere to study restrictions
• are sexually active and willing to adhere to contraceptive requirements
• are male or female ≥18 or (in Singapore) ≥21 years of age
• are medically stable

You may not qualify if:

• Individuals who:
• have had SARS-CoV-2 infection or COVID-19 disease.
• have had cancer except for cancers that were treated and that have low risk of returning
• have chronic kidney disease
• have some chronic lung diseases
• have some heart conditions
• have compromised immune systems
• are obese
• have sickle cell disease or some other blood disorders
• are current smokers and/or use illegal drugs
• have Type 2 diabetics
• are immunocompromised, immunodeficient or have had a transplant
• have autoimmune disease
• have other severe or uncontrolled diseases or disease that may interfere with the interpretation of the study
• have a positive test for hepatitis B or C or human immunodeficiency virus

Sponsors & Collaborators

• Arcturus Therapeutics, Inc.: lead

Study Sites (15)

Arcturus Investigational Site 103

Chandler, Arizona, 85224, United States

Location

Arcturus Investigational Site 107

Tucson, Arizona, 85741, United States

Location

Arcturus Investigational Site 112

San Diego, California, 92108, United States

Location

Arcturus Investigational Site 104

Melbourne, Florida, 32934, United States

Location

Arcturus Investigational Site 105

Orlando, Florida, 32806, United States

Location

Arcturus Investigational Site 106

Pinellas Park, Florida, 33781, United States

Location

Arcturus Investigational Site 109

The Villages, Florida, 32162, United States

Location

Arcturus Investigational Site 101

Peoria, Illinois, 61614, United States

Location

Arcturus Investigational Site 110

Rockville, Maryland, 20850, United States

Location

Arcturus Investigational Site 102

Anderson, South Carolina, 29621, United States

Location

Arcturus Investigational Site 111

Austin, Texas, 78705, United States

Location

Arcturus Investigational Site 108

Dallas, Texas, 75234, United States

Location

Arcturus Investigational Site 204

Singapore, 117599, Singapore

Location

Arcturus Investigational Site 201

Singapore, 169608, Singapore

Location

Arcturus Investigational Site 203

Singapore, 308433, Singapore

Location

MeSH Terms

Conditions

COVID-19; Severe Acute Respiratory Syndrome; Coronavirus Infections

Condition Hierarchy (Ancestors)

Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases

Results Point of Contact

• Title: Arcturus Therapeutics, Inc.
• Organization: Arcturus Therapeutics, Inc.

clinicaltrials@arcturusrx.com

858-900-2660

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Observer blind
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: sequential assignment

Study Record Dates

• First Submitted: November 25, 2020
• First Posted: December 16, 2020
• Study Start: January 7, 2021
• Primary Completion: March 1, 2022
• Study Completion: March 1, 2022
• Last Updated: May 15, 2025
• Results First Posted: May 15, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will not share

Locations

SG (3); US (12)