Immunogenicity and Safety Study of Self-amplifying mRNA COVID-19 Vaccine Administered With Influenza Vaccines in Adults

Summary

This is a multicenter, observer-blind, randomized, controlled phase 3 study to evaluate the immunogenicity, reactogenicity, and safety of an investigational self-amplifying RNA COVID-19 vaccine (ARCT-2303) administered concomitantly with quadrivalent influenza vaccines or standalone in adults who previously received authorized COVID-19 vaccine.

Timeline

Start

2024-03-27

Primary completion

2024-10-09

Completion

2024-11-21

Outcome

Met primary endpoint

paper both met the prespecified superiority criteria. PMID 40896462 ↗

paper The non-inferiority of the immune response against Omicron XBB.1.5.6 was also demonstrated when ARCT-2303 was co-administered or administered separately. PMID 40896462 ↗

release “Co-administration of ARCT-2303 and cell-based quadrivalent influenza vaccine (QIV; FLUCELVAX®, CSL) showed noninferior immune response vs standalone QIV administration.” arcturusrx.com ↗

release “Co-administration of ARCT-2303 and QIV showed noninferior immune response vs standalone ARCT-2303 administration.” arcturusrx.com ↗

Publications

• Giles ML, Tabora C, Baccarini C, Barrientos L, Vargas JC, Montellano ME, Nguyen P, Deshmukh S, Neville M, Hohenboken M, van Boxmeer J, Jin H, Bugarini R, Liu X, Walson JL, Verhoeven C, Smolenov I. Immunogenicity and safety of self-amplifying mRNA COVID-19 vaccine (ARCT-2303), with or without co-administration of seasonal inactivated influenza vaccine in adults: a phase 3, randomised, controlled, observer-blind, multicentre study. EClinicalMedicine. 2025 Aug 20;87:103428. doi: 10.1016/j.eclinm.2025.103428. eCollection 2025 Sep.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	ARCT-2303	Unknown	0.5 ml	Intramuscular
Subject	Influenza vaccine	Vaccine	0.5 ml	Intramuscular
Subject	Influenza vaccine, adjuvanted	Vaccine	0.5 ml	—

Indications