@abcnews: Merck and Moderna announced Wednesday that a personalized mRNA-based cancer vaccine succeeded in a large, late-stage trial among high-risk patients who had melanoma - a dangerous type of skin cancer. The individualized vaccine, when paired with the existing immunotherapy, Keytruda, is the first and only combination regimen that demonstrated success in potentially extending melanoma patients' lifespans. The complete data set has not been made public or submitted to regulators for approval yet, but the initial results appear promising.