New Delhi, Aug. 20 -- Merck and Moderna announced on Wednesday morning that a bespoke mRNA cancer vaccine, given alongside Merck's blockbuster immunotherapy Keytruda after surgery, significantly reduced disease recurrence and metastasis in patients whose high-risk melanoma had just been surgically removed, compared to Keytruda alone. The news sent Moderna shares soaring 144% while Merck's stock climbed more than 11%.P2...