Addressing issues of invalidity and non-infringement of patents asserted between direct competitors in the chewing gum market, the U.S. Court of Appeals for the Federal Circuit explained that in order to be entitled to rely on evidence of unexpected results commercial success or copying, the evidence of secondary translations must be tied to the claimed invention, i.e., the so-called nexus requirement.  WM Wrigley Jr. Co. v. Cadbury Adams USA LLC, Case Nos. 2011-1140, 1150 (Fed. Cir., June 22, 2012) (Bryson, J.) (Newman, J. concurring-in-part and dissenting-in-part).

Wrigley and Cadbury cross-alleged patent infringement of patents directed to chewing gum that provides a cooling sensation when chewed.  The Wrigley patent was directed to chewing gum containing a combination of menthol and WS-23 coolant, while the Cadbury patent was directed to a chewing gum containing a combination of menthol and WS-3 coolant. 

The district court found that one claim of Wrigley’s patent was invalid as anticipated by a patent to Shahidi and another was invalid as obvious in view of a patent to Luo and a publication by Parrish.  The lower court rejected Wrigley’s evidence of unexpected results, commercial success and copying.  The district court also found that Cadbury’s patent was not infringed, either literally or under the doctrine of equivalents.  Wrigley appealed. 

The Federal Circuit affirmed the lower court’s finding of obviousness as to Wrigley’s patent, concluding that Wrigley failed to demonstrate that the combination of menthol and WS-23, as claimed, resulted in an unexpected benefit beyond what was already known in the art.  The Court stated that prior art teaches that the combination of menthol and WS-3 yields “enhanced breath freshening effects” and that it was known that WS-3 and WS-23 share similar characteristics.  The Federal Circuit dismissed Wrigley’s evidence of unexpected results because there was no clear showing that the claimed invention resulted in the alleged unexpected benefits that were attributable to the claimed components and not to other factors, including sweetener levels, higher gum base and filler levels and more expensive ingredients.  Likewise, the Court dismissed Wrigley’s evidence of commercial success and copying for a lack of a nexus to the claimed invention.

The Federal Circuit also affirmed the lower court’s finding of anticipation based on Shahidi. The Federal Circuit found that Shahidi disclosed a number of different combinations of cooling and flavoring agents, one of which was the claimed combination of menthol, which Shahidi identified as one of the most suitable flavoring agents, and WS-23, which Shahidi listed among a group of other flavoring agents.

Regarding Cadbury’s patent, the Federal Circuit found that Cadbury could not prove infringement under the doctrine of equivalents because it had chosen to limit its claimed chewing gum composition to a certain species and not to the broader genus, despite knowing at the time of filing its application that WS-23 and WS-3 were interchangeable.  Cadbury’s decision to narrowly recite claim N-substituted-p-menthane carboxamides, which excludes WS-23, was detrimental to its infringement case.

In her dissent, Judge Newman pointed out that Shahidi, the purportedly anticipatory reference, “does not show the claimed combination at all, but merely presents the ingredients on lists” which can be combined in more than a million possible combinations.  Judge Newman also disagreed with the majority’s finding on obviousness, stating the record was “rife” with evidence demonstrating a nexus between Wrigley’s success of chewing gum combinations with menthol and WS-23, including Cadbury’s own internal records and marketing materials stressing the cooling effect of its reformulated chewing gum.