Phase 1/2 Study of Self-Replicating mRNA-Based COVID-19 Vaccine Completes Dosing

All the subjects in the first cohort have been dosed in the Phase 1/2 clinical study of a self-replicating mRNA-based investigational vaccine developed by Arcturus Therapeutics Holdings Inc. (San Diego, CA, USA).

Arcturus and Duke-NUS Medical School (Singapore) are jointly developing the LUNAR-COV19 (ARCT-021) investigational vaccine for COVID-19 using Arcturus’ STARR technology and a unique platform developed at Duke-NUS allowing rapid screening of vaccines for potential effectiveness and safety. The ARCT-021 vaccine candidate is devoid of viruses and does not utilize viral vectors or adjuvants. ARCT-021 utilizes Arcturus’ self-transcribing and replicating (STARR) mRNA technology and is delivered with Arcturus’s proprietary LUNAR lipid-mediated delivery system.


ARCT-021 preclinical data has shown highly promising results with 100% seroconversion for neutralizing antibodies after a single administration using a very low 2 µg dose. Neutralizing antibodies continued to increase for 60 days after dosing. Preclinical results also demonstrated robust CD8+ T-cell Induction and a Th1 biased T-helper cellular immune response. The ARCT-021 Phase 1/2 study includes two parts. In Phase 1, escalating doses will be administered as a single injection to younger adults aged 21 to 55 years old. Based upon the safety, immunogenicity and T-cell response data from this group, dose regimens will be selected for further evaluation in Phase 2 which includes cohorts in younger adults and older adults aged 56 to 80 years old.

“We are very pleased to have initiated dosing in our ARCT-021 Phase 1/2 study, and in fact, we have already completed dosing of all subjects in the first cohort of the study. Based on preclinical immunogenicity data, our self-replicating mRNA-based investigational vaccine could have a highly differentiated safety and efficacy profile, and may potentially allow vaccination at very low doses, and with a single administration. These favorable attributes could greatly facilitate mass vaccination campaigns necessary to control this global pandemic,” said Joseph Payne, President & CEO of Arcturus. “We look forward to sharing initial clinical data from this Phase 1/2 study in Q4 which we expect to enable dose selection for late phase clinical trials.”

Related Links:

Arcturus Therapeutics Holdings Inc.
Duke-NUS Medical School