Patent infringement cases involving software products can raise a number of unique challenges. One such challenge arises in connection with 35 U.S.C. Section 273, which provides a defense to patent infringement based on prior commercial use of a product or system. Evidence of prior commercial use of a device can be fairly straightforward; but evidence of prior commercial use of software can raise different and complex challenges in connection with source code, version control, and related issues. In an increasingly software-based world, companies should be mindful of these challenges, and best position themselves to raise—as needed—this Section 273 defense.

History and Purpose of 35 U.S.C. Section 273’s Prior Use Defense

In the wake of the Federal Circuit’s State Street Bank decision, which opened the floodgates for patenting methods of doing or conducting business, Congress passed the First Inventor Defense Act of 1999. See State Street Bank & Trust v. Signature Financial Group, 149 F. 3d 1368 (Fed. Cir. 1998); First Inventor Defense Act of 1999, 113 Stat. 1501A–555 (codified at 35 U. S. C. Section 273). The act was intended to “provide a limited defense to claims of patent infringement, see Section 273(b), for ‘methods of doing or conducting business’” which were already in use but, prior to State Street Bank, had not been viewed as patentable subject matter. See Bilski v. Kappos, 561 U.S. 593, 613–14 (2010) (Stevens, J., concurring).