NCT04668339

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

A Phase 2 Randomized, Observer-Blind, Placebo-Controlled Study to Assess the Safety, Reactogenicity, and Immunogenicity of the SARS CoV-2 Vaccine ARCT-021 in Healthy Adult Participants

• Status: Terminated
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 581 (actual)
• Sponsor: Arcturus Therapeutics, Inc. · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

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

Detailed description

This is a multiregional, multicenter, Phase 2, randomized, observer-blind study designed to evaluate the safety, reactogenicity, and immunogenicity of the study vaccine in younger and older adult participants. Enrolled participants will be randomly assigned to receive either study vaccine ARCT-021 or placebo (sterile saline). Approximately 600 participants (300 each in younger \[18 to \<56 years of age in United States or 21 to \<56 years of age in Singapore\] and older \[≥56 years of age\] participants) will be enrolled (including at least 50% of participants in the older cohort ≥65 years of age). Participants will be stratified by age and then randomly assigned (3 ARCT-021:1 placebo) to receive 2 doses of study vaccine separated by 28 days. At 180 days after second study vaccination (Day 208), participants in Study Groups 1, 2, and 3 will be randomly assigned again to receive a single booster dose of study vaccine (randomly assigned as 1 ARCT-021:1 placebo). Study Group 4 will not be randomized but will receive 1 dose of placebo at Day 208. Study Groups are summarized in Table 1. Study vaccine will be administered in an observer-blind fashion. Participants will be followed for safety and immunogenicity through 180 days after booster vaccination (Day 388). At a subset of clinical sites, all enrolled participants will also undergo blood sampling for evaluation of CMI responses. Vaccine doses will be assigned as follows: Younger Age Cohort: Study Group 1: n= 75 participants, ARCT-021 7.5 µg (first dose), Placebo (second dose Study Group 2: n= 75 participants, ARCT-021 5.0 µg (first dose), 5.0 µg (second dose) Study Group 3: n= 75 participants, ARCT-021 7.5 µg (first dose), 7.5 µg (second dose) Study Group 4: n= 75 participants, Placebo (first dose), Placebo (second dose) Booster Vaccine: Study Groups 1, 2, 3: 113 participants, ARCT-021 5.0 µg or 7.5 µg, 112 participants, Placebo Study Group 4: n= 75 participants, Placebo Older Age Cohort: Study Group 1: n= 75 participants, ARCT-021 7.5 µg (first dose), Placebo (second dose Study Group 2: n= 75 participants, ARCT-021 5.0 µg (first dose), 5.0 µg (second dose) Study Group 3: n= 75 participants, ARCT-021 7.5 µg (first dose), 7.5 µg (second dose) Study Group 4: n= 75 participants, Placebo (first dose), Placebo (second dose) Booster Vaccine: Study Groups 1, 2, 3: 113 participants, ARCT-021 5.0 µg or 7.5 µg, 112 participants, Placebo Study Group 4: n= 75 participants, Placebo A DSMB will be in place to independently review the safety data of participants. Pausing Rules are also utilized in this study to reduce risk to study participants. The expected duration of participation for an individual participant is approximately 14 months, inclusive of the Screening period.

Conditions

• Covid19
• SARS-CoV Infection
• Corona Virus Infection

Interventions

Type	Name	Description
BIOLOGICAL	ARCT-021 single dose priming	ARCT-021 higher dose (one dose) + placebo (one dose)
BIOLOGICAL	ARCT-021 two lower dose priming	ARCT-021 lower dose (two doses, Day 0 and Day 28)
BIOLOGICAL	ARCT-021 two higher dose priming	ARCT-021 higher dose (two doses, Day 0 and Day 28)
BIOLOGICAL	Placebo (two doses), priming	Placebo (two doses, Day 0 and Day 28)
BIOLOGICAL	Randomized booster	ARCT-021 (single dose) OR placebo, booster
BIOLOGICAL	Placebo booster	Placebo (single dose)

Timeline

• Start date: 2021-01-07
• Primary completion: 2022-03-01
• Completion: 2022-03-01
• First posted: 2020-12-16
• Last updated: 2025-05-15
• Results posted: 2025-05-15

Locations

15 sites across 2 countries: United States, Singapore

Regulatory

• FDA-regulated drug study