Trying A Patent Validity Case In A Post-KSR World

On April 30, 2007, the U.S. Supreme Court issued its most recent patent decision: KSR International Co. v. Teleflex Inc., 127 S. Ct. 1727 (2007), in which it rejected what it deemed to be a "rigid" and "narrow" test for determining the validity of a patent. Following the decision, it was widely reported that the KSR opinion would render patents more prone to invalidity challenges on the basis of obviousness. However, based on the author's experience in a recent case in which patent validity was raised as the principal defense to our client's infringement claim, it is clear that the practical impact of KSR can be contained if appropriate strategies are employed at trial.

In KSR, a unanimous decision authored by Justice Kennedy, the Supreme Court held that an "expansive and flexible approach" must now be used in patent validity challenges based on obviousness, explaining that, "[r]igid preventive rules that deny fact-finders recourse to common sense are neither necessary under our case law nor consistent with it."

Under United States Code, Title 35, Section 103, a patent is invalid if it would have been obvious to a person of "ordinary skill" in the technology to which the invention pertains at the time the invention was made. In order to prove a patent is obvious, the party challenging the patent must use written information that predated the invention ("prior art"), usually in the form of earlier patents or technical articles, to show that the patent claims were obvious. Unlike "anticipation" challenges under Section 102 (which require that each element of a patent claim be disclosed in a single piece of prior art), a party challenging the validity of a patent claim as "obvious" under Section 103 is allowed to combine different items of prior art-which may disclose different elements within the challenged patent claim-to prove obviousness.

For many years before the KSR decision, the federal courts had applied a test that no patent could be found "obvious" (and thus invalid) unless there was some prior "teaching, suggestion, or motivation" indicating how the prior art could be combined to make the invention obvious. The "teaching, suggestion, or motivation" test, described as the "TSM test" by the Supreme Court in KSR, effectively required that the prior art being relied on to challenge the validity of a patent claim set forth some explicit suggestion, or "motivation," to combine the different pieces of prior art.

According to the Supreme Court in KSR, this test was unnecessarily rigid and conflicted with the Court's earlier decision in Graham v. John Deere, Co. of...