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 (mRNA-1273), 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.

"We are very pleased that mRNA-1283 has now met its primary vaccine efficacy endpoint in Phase 3, and showed higher efficacy in adults compared to Spikevax," said Stéphane Bancel, Chief Executive Officer of Moderna. "With five vaccine programs that have achieved positive Phase 3 results, Moderna's platform is consistently demonstrating its ability to address significant unmet needs in public health."

The ongoing Phase 3 clinical trial (ClinicalTrials.gov Identifier: NCT05815498) 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 μg dose of mRNA-1283, while the other half received a 50 μg dose of mRNA-1273 (Spikevax). 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.