A slide in shares of pharmaceutical firm Merck and biotech company Amgen helped drag the blue-chip index back from the highs notched in the broad rally Friday after Federal Reserve Chair Jerome Powell signaled that the central bank could lower interest rates next month. The Dow fell 0.8%, with Merck losing 2.4% and Amgen falling 1.8%. “There is some lack of comfort that Powell’s assertion that tariffs will be mostly a one-time increase in prices will be how things actually play out,” wrote Louis Navellier, chief investment officer of Navellier & Associates, in a Monday note.