
Moderna and Merck are surging today after the two companies said their experimental mRNA-based treatment succeeded in a late-stage study of high-risk melanoma patients. The SPDR S&P Biotech ETF (XBI) jumped nearly 5%, while the NYSE Arca Pharmaceutical Index climbed over 3%. A positive clinical-trial result typically moves the companies developing the drug—and perhaps their closest competitors—not the entire healthcare sector.






