
Drug company stocks soared following news that Moderna and Merck’s experimental mRNA-based cancer vaccine succeeded in a late-stage trial at preventing melanoma from returning or spreading. The S&P health-care sector is on track for an all-time closing high, as is Merck, according to data that goes back to 1972. As of Wednesday afternoon, Moderna’s stock had more than doubled, something that a member of the S&P 500 hasn't done in a single day since 2008, according to Dow Jones Market Data.






