On Mar. 15, 2021, Moderna announced that the first participants had been dosed in the Phase 1 study of mRNA-1283, the Company’s next generation COVID-19 vaccine candidate.

This Phase 1 dose-ranging study assessed the safety and immunogenicity of mRNA-1283, a next-generation vaccine candidate against COVID-19. mRNA-1283 encodes for the portions of the SARS-CoV-2 spike protein critical for neutralization, specifically the Receptor Binding Domain (RBD) and N-terminal Domain (NTD).

The encoded mRNA-1283 antigen is being developed as a potentially refrigerator-stable mRNA vaccine that will facilitate distribution and administration by healthcare providers.

This Phase 1 study will evaluate three dose levels, 10 μg, 30 μg, and 100 μg, of the mRNA-1283 vaccine candidate given to healthy adults as a 2-dose series, 28 days apart, and one dose level, 100 μg, of mRNA-1283 given to healthy
adults in a single dose.

These will be compared with a 2-dose series of 100 μg of mRNA-1273, the currently authorized dose level. mRNA-1283 is intended to be evaluated in futures studies for use as a booster dose for previously vaccinated or seropositive as well as in a primary series for seronegative individuals.