Cadence Pharmaceuticals Inc. v. Exela Pharma Sciences LLC
114 U.S.P.Q. 2d (BNA) 1177, 780 F.3d 1364, 2015 U.S. App. LEXIS 4700 (2015)
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Rule of Law:
Under the doctrine of equivalents, changing the order of steps in a claimed process can constitute infringement if the difference is insubstantial. The concept of claim "vitiation" is not a separate legal test that forecloses analysis, but rather is a legal conclusion that no reasonable fact-finder could find equivalence between the claimed element and the accused element.
Facts:
- SCR Pharmatop and Cadence Pharmaceuticals, Inc. (Cadence) own and license patents for stable, aqueous formulations of acetaminophen.
- U.S. Patent No. 6,222,222 (the '222 patent) is directed to a stable liquid acetaminophen formulation containing a buffering agent.
- U.S. Patent No. 6,992,218 (the '218 patent) discloses a method for creating stable acetaminophen formulations by deoxygenating the aqueous solution (i.e., after acetaminophen is added) to an oxygen content below 2 parts-per-million (ppm).
- Cadence markets an injectable acetaminophen product called Ofirmev®.
- Exela PharmSci Inc. (Exela) developed a generic equivalent of Ofirmev®.
- Exela's process for its generic product involves deoxygenating the aqueous solvent before adding acetaminophen to it.
- Exela's formulation contains sodium ascorbate, which functions as an antioxidant.
Procedural Posture:
- Exela filed an Abbreviated New Drug Application (ANDA) with the FDA, which included a Paragraph IV certification that Cadence's '222 and '218 patents were invalid and not infringed.
- Cadence sued Exela in the U.S. District Court for the District of Delaware for patent infringement under 35 U.S.C. § 271(e)(2).
- The district court conducted claim construction and held a bench trial.
- The district court found that Exela literally infringed the '222 patent and infringed the '218 patent under the doctrine of equivalents.
- The district court also ruled that Exela failed to prove by clear and convincing evidence that the '218 patent was invalid for obviousness.
- Exela (appellant) appealed the district court's final judgment to the U.S. Court of Appeals for the Federal Circuit, with Cadence as the appellee.
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Issue:
Does a process that deoxygenates a solvent before adding an active ingredient infringe, under the doctrine of equivalents, a patent claim that requires deoxygenating the solution after the active ingredient has been added?
Opinions:
Majority - Linn, Circuit Judge.
Yes, a process that reverses the order of steps can infringe under the doctrine of equivalents if the difference between the claimed process and the accused process is insubstantial. The court affirmed the district court's finding that Exela's process of deoxygenating the solvent before adding acetaminophen was an insubstantial difference from the '218 patent's claim of deoxygenating the solution after adding acetaminophen. The court reasoned that expert testimony established that the timing of deoxygenation had no impact on the stability of the final product, which was the goal of the invention. The court rejected Exela’s argument that its process was the 'antithesis' of the claimed method and would vitiate the claim limitation. It clarified that 'vitiation' is not a threshold test but a conclusion that a reasonable fact-finder could not find equivalence. Here, the evidence supported the finding of equivalence. The court also affirmed the finding of literal infringement of the '222 patent, agreeing with the district court's construction of 'buffering agent' as simply 'an agent that helps the formulation resist change in pH,' which did not require a specific concentration.
Analysis:
This decision significantly clarifies the role of the 'claim vitiation' doctrine within the broader doctrine of equivalents. By framing vitiation as a conclusion of non-equivalence rather than a threshold barrier to analysis, the court prevents accused infringers from avoiding liability merely by labeling a modification as the 'antithesis' of a claimed element. This reinforces the fact-intensive nature of the 'insubstantial differences' test, ensuring that infringement analysis focuses on the actual impact of a change rather than on semantic labels. The case also provides important guidance on the nexus requirement for secondary considerations of non-obviousness, confirming that a commercially successful product that is an 'equivalent' of the claimed invention, not just a literal embodiment, can serve as evidence supporting the patent's validity.
