Equivalence Determination Does Not Depend On Labels Like "Vitiation" and "Antithesis," But On The Substantiality of Relevant Differences

Cadence Pharmaceuticals Inc. v. Exela Pharma Sciences LLC, __ F.3d __ (Fed. Cir. Mar. 23, 2015) (Reyna, LINN, Wallach) (D. Del.: Stark, J.) (2 of 5 stars)

Federal Circuit affirms infringement and no invalidity of two patents concerning aqueous phenol formulations.

CLAIM CONSTRUCTION ('222 PATENT): The term "buffering agent" was correctly construed as "[an] agent that helps the formulation resist change in pH," and did not require efficacy and concentrations limitations. A statement in the specification that the concentration "may be" between a range was not limiting, and the addition of the term in response to a rejection during prosecution only shows that a buffering agent is necessary. Federal Circuit affirmed the infringement ruling, which was based on the correct construction of that term.

DOCTRINE OF EQUIVALENTS ('218 PATENT): Exela's accused process that added an active ingredient after a solvent is deoxygenated infringed the claim limitation that required the active ingredient to be dissolved before deoxygenation under the DOE. The conclusion that the difference in timing was insubstantial was supported by expert testimony. Federal Circuit rejected Exela's vitiation argument that there can be no equivalence finding because deoxygenating after adding the active ingredient is the "antithesis" of deoxygenating before. Vitiation "is not an exception or threshold determination that forecloses resort to the doctrine of equivalents, but is instead a legal conclusion of a lack of equivalence based on the evidence presented and the theory of equivalence asserted." Slip Op. at 11. "Characterizing an element of an accused product as the 'antithesis' of a claimed element is also a conclusion that should not be used to overlook the factual analysis required to establish whether the differences between a claimed limitation and an accused structure or step are substantial vel non. The determination of equivalence depends not on labels like 'vitiation' and 'antithesis' but on the proper assessment of the language of the claimed limitation and the substantiality of whatever relevant differences may exist in the accused structure." Id. A reasonable trier of fact could conclude that the difference between Exela's process and the claims was insubstantial.

CLAIM CONSTRUCTION ('218 PATENT): The plain meaning and specification supported the conclusion that the vacuum stoppering step was optional. Moreover, there was no clear and unmistakable disavowal that supported a construction that made this step mandatory. The infringement finding was thus affirmed.

OBVIOUSNESS ('218 PATENT): It would not have been obvious to combine two prior art references because one did not address the degradation mechanism of acetaminophen. Moreover, the Examiner initially rejected the '218 claims on essentially the same grounds, but the patent issued nonetheless, and the Patent Office is "presumed to have properly done its job' when it ultimately allowed the '218 patent." Id. at 17. Secondary considerations further supported nonobviousness: marketing of a product that is not literally covered by the claims is not per se irrelevant; "somewhat unexpected" results are still evidence of non-obviousness; and licensing of the patent is evidence of a belief the patent is valid.

Authors: Leah A. Edelman, Cherylyn Esoy Mizzo