Moderna’s Cancer Vaccine Breakthrough Triggers Massive Rally, Then Profit-Taking

Moderna’s personalized cancer vaccine mRNA-4157 (intismeran autogene) paired with Merck’s Keytruda hit key Phase 3 melanoma endpoints, delivering a 49% reduction in recurrence or death versus Keytruda alone and sparking a 177% one‑day stock surge before shares retraced about 20% as investors took profits; Moderna’s pipeline spans nine Phase 2/3 studies across melanoma, NSCLC, bladder and kidney cancers, despite a $950 million settlement and a norovirus program setback, while Merck’s KEYTRUDA franchise remains a critical driver for oncology growth.