Written by Paul Chang, Ph.D. and Brenden Gingrich, Ph.D.

Anticipation by inherent disclosure requires that a single prior art reference necessarily includes the unstated limitation. The unpredictable nature of biological processes means that winning summary judgment of invalidity based on inherent anticipation is often difficult.

The patents-in-suit (U.S. Patent Nos. 8,415,137 and 8,609,399) in U.S. Water Services, Inc. v. Novozymes relate to methods of reducing insoluble deposits of phytic acid on equipment (“fouling”) during ethanol production by using phytase, an enzyme that breaks down phytic acid. The asserted prior art explicitly disclosed adding phytase during ethanol production to improve liquefaction and fermentation, but did not disclose reducing fouling. Thus, the issue was whether the prior art inherently disclosed this limitation of the claims at issue.

In opposing Novozymes’ motion for summary judgment of invalidity based on inherent anticipation, U.S. Water Services provided the district court with expert testimony that adding phytase in the manner disclosed in the prior art may not necessarily lead to a reduction in fouling as claimed. U.S. Water Services’ experts testified that “[n]umerous factors can impact the ability of phytases to convert phytic acid to its hydrolysis products during ethanol processing” and that “one can employ phytase enzyme according to . . . [the asserted prior art] in ways that . . . would be insufficient to have any effect on the formation of deposits.” Despite this testimony, the district court granted Novozymes’ summary judgment motion, reasoning that a reduction in fouling would be a natural result of the methods of adding phytase during ethanol production disclosed by the prior art.

The Federal Circuit vacated the district court’s grant of Novozymes’ motion for summary judgment of invalidity based on inherent anticipation. The court found that U.S. Water Services adduced evidence, including expert testimony, that practicing the prior art will not always result in a reduction in fouling. Because the conclusion of inherency must be established by inevitability, and not merely by probabilities or possibilities, the court reasoned that the district court improperly deemed U.S. Water Services’ evidence irrelevant and concluded that a genuine dispute of material fact exists as to whether the patents-in-suit are inherently anticipated.

Biological processes are often sensitive to reaction conditions. Consequently, when litigating a patent on a biotechnology invention, a patentee may be able to provide evidence that practicing the general teaching of the prior art does not necessarily result in an unstated limitation being present. Such evidence should prevent a trial court from granting an alleged infringer’s motion for summary judgment of invalidity based on inherent anticipation, and may ultimately lead to a finding of no anticipation.