Cadence Pharmaceuticals Inc. et al. v. Exela PharmSci Inc. et al.


Docket No. 2014-1184

REYNA, LINN, WALLACH
March 23, 2015

Brief Summary: DC findings regarding claim construction, infringement determination (DOE) and no obviousness affirmed.

Summary: Exela appealed DC claim construction of certain claim terms of US 6,028,222 and 6,992,218 relating to aqueous phenol formulations (e.g., acetaminophen), referred to as paracetamol. Cadence markets the injectable acetaminophen product Ofrimev®. The suit arose after Exela filed an ANDA seeking approval of a generic equivalent to Ofrimev®. The FC reviews questions of claim construction and obviousness for clear error and the ultimate determinations de novo (“the de novo standard we have long applied” is proper here “[b]ecause the district court’s claim constructions were based solely on the intrinsic record” (Fenner, US 2015)). And infringement is reviewed “for clear error when tried without a jury.” Regarding the term “buffering agent” of the ‘222 patent, Exela argued it should be present “in an effective concentration to resist material changes in pH” but the DC construed it to mean “[a]n agent that helps the formulation resist change in pH” based on the specification. The FC panel agreed with the DC, seeing “nothing in the intrinsic record to warrant adding requirements of effective concentration or resistance to material change” (“The statement in the specification that the concentration of the buffer ‘may be’ between 0.1 and 10 mg/ml is not limiting, because even if ‘all of the embodiments discussed in the patent’ included a specific limitation, it would not be ‘proper to import from the patent’s written description limitations that are not found in the claims themselves.’” Flo Healthcare, FC 2012) The FC panel affirmed the DC conclusion of infringement as the inclusion of sodium ascorbate in Exela’s formulation met the buffering agent limitation.

The DC also held Excela’s process did not literally infringe the ‘218 patent but did infringe under the DOE (claim 1: “optionally the deoxygenation of the solution is completed by the addition of an antioxidant”). Exela’s argument is that the methods differ substantially because of the timing of deoxygentation. The DC relied on Cadence’s expert testimony who explained “that adding acetaminophen before or after the deoxygenation step would have no impact on the stability of the final product” (“Exela’s speculation that other differences between its formulation and the claimed formulation may be responsible for stability is insufficient to create a definite and firm conviction that the district court made a mistake.”) The DC also rejected Exela’s claim vitiation argument based on Planet Bingo (FC 2006) and the FC explained “Exela’s reliance on Planet Bingo is misplaced” (unlike this case, changing the steps in Planet Bingo resulted in a substantially different game (“Exela fundamentally misunderstands the doctrine of claim vitiation…[It] is not an exception or threshold determination that forecloses resort to the [DOE], but is instead a legal conclusion of a lack of evidence based on the evidence presented and the theory of equivalence asserted.”)). The DC also determined the “vacuum stoppering step” was optional because “the language of claim 1 plainly indicates the word ‘optionally’ applies to both the first and second clauses, which are connected by the word ‘and’” and statements made during prosecution “do not rise to the level of an explicit disclaimer”; the FC agreed (“The conclusion…is supported by the specification” and the prosecution history…“no clear and unmistakable disavowel”.)

Exela also unsuccessfully argued to the DC that the ‘218 patent was obvious over the ‘222 patent, the only difference between the two patents being that the ‘222 patent did not disclose decreasing the oxygen content to below 2 ppm (claim 1) or less (dependent claims), in view of the “Palmieri article” which teaches “deoxygenating pyrgallol solutions to below 0.05 ppm leads to increased stability.” The DC was not persuaded because “pyrogallol degrades by oxidation while acetaminophen degrades primarily by hydroloysis and because deoxygenation to levels below 2 ppm was ‘technical[ly] difficult[]’” and Cadence’s product “fulfilled a long-felt need, was a commercial success, was licensed and was praised in the industry” (the license providing “evidence of a belief that the ‘218 patent was valid”). The FC opinion explained “Exela bears a difficult burden…since the Examiner initially rejected the claims of the ‘218 patent for essentially the same reasons as defendants now raise” (the “Patent Office is ‘presumed to have properly done its job’ when it ultimately allowed the ’218 patent” (citing PowerOasis, FC 2008: “When no prior art other than that which was considered by the PTO examiner is relied on by the attacker, he has the added burden of overcoming the deference that is due to a qualified government agency presumed to have properly done its job, which includes one or more examiners who are assumed to have some expertisein interpreting the references and to be familiar from their work with the level of skill in the art and whose duty it is to issue only valid patents.”)), it must “prove invalidity by clear and convincing evidence” (Microsoft, US 2011), and only clearly erroneous factual determinations will be overturned. It concluded Exela did not meet that burden (based in part on expert testimony).

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