Moderna announced a Phase 3 failure for its congenital cytomegalovirus (CMV) vaccine, prompting the company to halt most development of the candidate. The mRNA-1647 program missed primary efficacy endpoints in a large trial, undercutting expectations that the shot could become a multibillion-dollar product. Moderna said it will reassess priorities across its vaccine portfolio and focus resources on other pipeline areas. The setback compounds pressure on the company following recent respiratory vaccine and organizational challenges.