Trial design and participants
chronic diseases
CHRONIC DISEASES, INFLUENZA
This is a first-in-human, phase 1/2, randomized, observer-blinded study at 20 sites in the United States to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1010 in adults ≥18 years of age (NCT04956575). The study comprises 3 parts, which assessed mRNA-1010 or placebo in healthy adults in Part 1, followed by additional dose-ranging assessments in Parts 2 and 3 to evaluate mRNA-1010 versus licensed comparator vaccines in medically stable adults. This report summarizes interim findings for Parts 1 and 2 of the study, with final results to be separately reported.Eligible participants in Part 1 of the study were healthy adults ≥18 years of age (Supplementary Fig. Part 2 of the study enrolled medically stable adults ≥18 years of age, excluding those adults with chronic diseases requiring ongoing medical intervention within the 3 months before enrollment and with immunocompromising conditions or medications. Approximately 500 participants were planned to be randomly assigned (3:3:3:1) to receive a single dose of mRNA-1010 (25 µg, 50 µg, or 100 µg) or a licensed quadrivalent seasonal influenza vaccine (Afluria®; Seqirus Pty Ltd, Parkville, Victoria, Australia; Supplementary Fig. In each part of the study, participants were followed for approximately 6 months, with a single dose of the vaccine administered on Day 1 and the final study visit on Day 181 (Month 6). Both parts of the study had a planned interim analysis to evaluate safety and immunogenicity data of all participants through Day 29. Participants in Part 1 were recommended to receive a licensed 2021–2022 NH seasonal influenza vaccine after Day 29 of the study.The study was conducted in accordance with the protocol, applicable laws, and regulatory requirements, as well as International Council for Harmonization Good Clinical Practice guidelines, and the consensus ethical principles derived from international guidelines, including the Declaration of Helsinki and Council for International Organizations of Medical Sciences International Ethical Guidelines. The protocol was approved by the central institutional review board (Advarra, Inc., Columbia, MD) prior to study initiation, and written informed consent was obtained from all participants before enrollment.