Drug makers oppose a CMS proposal to undermine co-pay coupons by subtracting the value of those coupons from the prices companies charge Medicaid. The Pharmaceutical Research and Manufacturers of America also says CMS overstepped its legal authority by proposing a new definition of “line extension” that would make drug companies pay additional rebates when they find new uses for existing drugs, combine drugs or create new ways to administer them. The policies are part of a rule CMS proposed to...