St. Mary's Law Journal


The doctrine of equivalents, which Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. threatens to overturn, is an equitable doctrine and should therefore provide patentees and competitors equal and fair protection. Prior to Festo, the Federal Circuit used two approaches: the complete bar rule and the flexible bar rule. Under the complete bar rule, the author must completely copy the patented art for infringement to occur, this is otherwise known as literal infringement. In contrast, under the flexible bar rule, infringement can occur if the product is closely related to the prior art. Federal Circuits have officially adopted the complete bar rule in Festo and are abandoning the flexible bar rule. Without the full use of the doctrine of equivalents, copyists could slightly modify inventions with insubstantial and inconsequential changes and avoid patent infringement. The resulting injustice promotes concealment of inventions, which defeats Congress’s primary purpose for allowing patents: to put everyone on notice of the art. The burden of proof rests squarely on the patentee to prove that the accused art is substantially the same and accomplishes substantially the same result even though it differs in name, form, or shape. In biotechnology, a single protein out of twenty-five other proteins can be changed, and the art would substantially still be the same and would not infringe under Festo. This stifles biomedical advances because copyists now have much more leeway than under the full use of the doctrine of equivalents. The United States Supreme Court has granted certiorari and will consider the effects of the Festo ruling. It is critical to patents, especially in the biomedical industry, that the doctrine of equivalents receives affirmation of its existence, and the complete bar rule is reversed.


St. Mary's University School of Law