Merck plans to reduce the size of its U.S. sales force by 15%, firing 1,200 reps. The move comes in the wake of slowing cholesterol drug sales as well as increased generic competition, according to the company.     “Merck is taking this step as part of our previously disclosed, continuing efforts to optimize our cost base and improve Merck’s effectiveness and efficiency across all aspects of our business as part of our Plan to Win strategy,” said Kenneth Frazier, president, ...