US pharmaceutical giant Merck said Thursday that chief executive Ken Frazier will retire on June 30. Frazier, one of few African Americans to run a major US company, will stay on the board as executive chairman during a transition period, a statement said. Word of the change in leadership came as Merck reported profits of $7.1 billion in 2020, a decline of 28 percent from the previous year, on revenue of $48 billion, which was up by 2.5 percent. lo/dw/wai