Moderna reported that its cytomegalovirus (CMV) mRNA vaccine mRNA‑1647 failed to meet the primary efficacy endpoint in a pivotal Phase III trial and stopped development of the program. The Phase III CMVictory study missed its prevention endpoint in seronegative women, prompting the company to abandon the program despite earlier optimism. Moderna said it will continue to focus on other pipeline priorities, including oncology vaccines. The outcome highlights that mRNA platforms do not guarantee success across indications and that vaccine immunology remains complex even for advanced platforms.