An increase to the length of a patent's term.

Under Section 156 of the Patent Act, a patent owner can obtain an extension of a patent's term if the patent covers a product, or a method of manufacturing or using a product, that is subject to regulatory review before it can be commercially marketed or used—for example, a drug product that was approved by the Food and Drug Administration (FDA) (35 U.S.C. § 156). The length of the extension is based on the length of the regulatory review and includes any patent term adjustment under 35 U.S.C. § 154(b). Section 156 sets out several limitations on the availability and length of patent term extensions.

For more information on patent term extensions, see Practice Note, Hatch-Waxman Act: Overview: Patent Term Extension.