What is "evergreening"

vb. (present participle of evergreen English)

Evergreening refers to a variety of legal, business and technological strategies by which producers extend their patents over products that are about to expire, in order to retain royalties from them, by either taking out new patents (for example over associated delivery systems, or new pharmaceutical mixtures), or by buying out, or frustrating competitors, for longer periods of time than would normally be permissible under the law.

Evergreening is not a formal concept of patent law; it is best understood as a social idea used to refer to the myriad ways in which pharmaceutical patent owners use the law and related regulatory processes to extend their high rent-earning intellectual property rights particularly over highly profitable (either in total sales volume or price per unit) "blockbuster" drugs.

Thus, while the courts are an instrument frequently used by pharmaceutical brand name manufacturers to prolong their patent royalties, evergreening is rarely mentioned explicitly by judges in patent protection cases. The term usually refers to threats made to competitors about a brand-name manufacturer's tactical use of pharmaceutical patents (including over uses, delivery systems and even packaging), not to extension of any particular patent over an active product ingredient.