Long‑term follow-up from a trial combining a Merck‑Moderna cancer vaccine candidate with Keytruda shows a sustained 49% reduction in risk of recurrence or death at five years, boosting the companies’ program as they near phase 3 decisions. The updated data reinforce the durability of the vaccine’s adjuvant benefit when added to PD‑1 blockade, supporting regulatory and development planning ahead of larger trials. The result increases the commercial and clinical case for integrating neoantigen or vaccine platforms with immune checkpoint inhibitors in adjuvant oncology settings.