Moderna announces Phase 3 trial of mRNA-1283 met primary efficacy endpoint

Moderna announced that its Phase 3 trial of mRNA-1283, an investigational next-generation COVID-19 vaccine, has met its primary efficacy endpoint, demonstrating non-inferior vaccine efficacy against COVID-19 compared to Spikevax. The Company also announced that higher efficacy was observed in adults 18 years of age and older compared to Spikevax, with a consistent trend observed in the subset of adults age 65 and older. Positive interim immunogenicity results for mRNA-1283 in this study were previously reported in March 2024. The ongoing Phase 3 clinical trial is a randomized, observer-blind, active-controlled study of approximately 11,400 individuals aged 12 years and older. Half of the participants received a 10 undefined dose of mRNA-1283, while the other half received a 50 undefined dose of mRNA-1273. Today’s vaccine efficacy data are consistent with the previously announced immunogenicity results from the study, which showed that mRNA-1283 had higher neutralizing antibody responses against both Omicron BA.4/5 and ancestral SARS-CoV-2 than mRNA-1273, with the highest geometric mean titer ratios observed in adults and in the subset of participants aged 65 years and older. In the trial, mRNA-1283 was found to have a similar safety profile to Spikevax. The most commonly solicited side effects were injection site pain, fatigue, headache and myalgia. Moderna’s combination vaccine candidate against influenza and COVID-19, mRNA-1083, includes mRNA-1283. That vaccine candidate recently announced positive results in its separate Phase 3 trial. Moderna plans to present the Phase 3 clinical data for mRNA-1283 at an upcoming conference as well as submit it for publication. The Company will also engage with regulators on the next steps for the program.