Embedded Player NPR's Patricia Neighmond reports on a practice known as "evergreening" by drug companies that many blame for the high prices of some prescriptions. Companies seek to find ways to extend the patents on their brand name medications - sometimes by tiny changes in a pill's dose or its formulation. An extension of a patent delays the introduction of cheaper generic versions of a drug, permitting brand-name makers to reap many extra billions in profits. Drug companies defend the practice, saying they must recoup the high costs of developing new drugs.