Nearly 45 years have ticked by since the U.S. Supreme Court’s decision in Walker Process Equipment Inc. v. Food Machinery Corp., 382 U.S. 172 (1965), established an antitrust cause of action based on fraudulent procurement of a patent, but it remains one of a set of viable and oft-asserted antitrust counterclaims in patent cases. Antitrust counterclaims in patent litigation are perceived to add a level of complexity to the subject matter and increase the discovery burden on the parties and the court. Accordingly, judges have increasingly turned to bifurcation of the patent and antitrust portions of the case as a means of addressing the supposed added complexity and burden.

The prevalence of antitrust counterclaims, and particularly Walker Process claims, in patent cases may be traced to the prominence of the inequitable conduct defense in patent cases. The inequitable conduct defense — which asserts that the patent applicant misrepresented or omitted relevant prior art or other information that is material to patentability — renders the patent unenforceable. The inequitable conduct defense is now so prevalent in patent infringement suits that the U.S. Court of Appeals for the Federal Circuit has labeled the defense an “absolute plague” and a “scourge.” Burlington Indus Inc. v. Dayco Corp., 849 F.2d 1418, 1422 (Fed Cir. 1988); Ferring B.V. v. Barr Labs., 437 F.3d 1181 (Fed. Cir. 2006) (Newman, J., dissenting).