On Jun. 11, 2020, Moderna announced progress on late-stage development of mRNA-1273, the Company’s mRNA vaccine candidate against COVID-19. Moderna has finalized the Phase 3 study protocol based on feedback from the U.S. U.S. Food and Drug Administration (FDA). The randomized, 1:1 placebo-controlled trial was expected to include approximately 30,000 participants enrolled in the U.S.

The trial’s primary endpoint was the prevention of symptomatic COVID-19 disease; key secondary endpoints include prevention of severe COVID-19 disease (as defined by the need for hospitalization) and prevention of infection by SARS-CoV-2, the virus that causes COVID-19. The primary efficacy analysis was an event-driven analysis based on the number of participants with symptomatic COVID-19 disease.

Based on the results of the Phase 1 study, the 100 μg dose level was chosen as the optimal dose level to maximize the immune response while minimizing adverse reactions. Moderna had completed manufacture of vaccine required to start the Phase 3 study. The Company expected dosing in the Phase 3 study to begin in July.