The recently signed Leahy-Smith Patent Reform Act, better known as the America Invents Act, significantly expands the defense to patent infringement based on prior commercial use and applies to any patent issued on or after September 16, 2011.

Previously, that defense was limited to actions involving business method patents. Now, it includes prior commercial use of any process or machine, manufacture, or composition of matter used in a manufacturing or other commercial process. To rely on this defense, an accused infringer must have, acting in good faith, commercially used the subject matter in the United States. The use must have been either in connection with an internal (inter-company) commercial use or a bona fide sale or other commercial transfer. Finally, the commercial use must have occurred at least one year before the earlier of the effective filing date of the asserted invention or a public disclosure of the asserted invention. The defense must be proved by clear and convincing evidence.