United States: Claim Vitiation Does Not Foreclose The DOE

In Cadence Pharmaceuticals Inc. v. Exela PharmSci Inc., No. 14-1184 (Fed. Cir. Mar. 23, 2015), the Federal Circuit affirmed the district court's claim construction, rulings of literal infringement and infringement under the DOE, and nonobviousness determination of the asserted claims.

SCR Pharmatop and Cadence Pharmaceuticals Inc. (collectively "Cadence") are the owner and exclusive licensee, respectively, of U.S. Patent Nos. 6,028,222 ("the '222 patent") and 6,992,218 ("the '218 patent"), which are directed to stable aqueous acetaminophen formulations.  Cadence markets an injectable acetaminophen product, which is approved by the FDA and is marketed under the name Ofirmev®.  The FDA's Approved Drug Products with Therapeutic Equivalence Evaluations ("Orange Book") lists the '222 and '218 patents as covering Ofirmev®.

Exela PharmSci Inc. ("Exela") filed an ANDA, seeking approval to market a generic version of Ofirmev®.  The ANDA included a certification pursuant to 21 U.S.C. § 355(j)(2)(A)(vii)(IV) ("Paragraph IV certification"), asserting that the '222 and '218 patents were invalid and not infringed.  In response, Cadence sued Exela for infringing certain claims of the '222 and '218 patents.  Following a bench trial, the district court found the '222 patent not invalid and literally infringed, and the '218 patent not invalid and infringed under the DOE.  Exela appealed both of the district court's infringement decisions and its validity determination as to the '218 patent.  It did not appeal the district court's validity determination as to the '222 patent.

"'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.

On appeal, the Federal Circuit affirmed the district court's judgment with respect to both the '222 and '218 patents.  First, the Court stated that Exela's appeal regarding the '222 patent turned on claim construction.  Specifically, the district court construed the term "buffering agent" in claim 1 to mean "[a]n agent that helps the formulation resist change in pH."  Slip op. at 6 (alteration in original) (quoting Cadence Pharm., Inc. v. Paddock Labs. Inc., 886 F. Supp. 2d 445, 456 (D. Del. 2012)).  Exela argued that a buffering agent must be present in sufficient concentration to prevent a material change in pH, relying on particular embodiments and the prosecution history.  The Court agreed with the district court, however, finding "nothing in the intrinsic record to warrant adding requirements of effective concentration or resistance to material change."  Id. at 7.  The Court then affirmed the district court's finding that claim 1 of the '222 patent was infringed based on the district court's finding that sodium ascorbate present in Exela's formulation met the buffering agent limitation as construed by the Court.

Second, the Federal Circuit affirmed the district court's findings regarding the '218 patent.  Exela argued that the district court erred in holding that Exela's process infringed the asserted claims under the DOE.  Specifically, Exela contended that deoxygenating after adding the active ingredient is the "antithesis" of deoxygenating before adding the active ingredient.  Id. at 10.  Because such a substitution would "vitiate" the claimed limitation, Exela argued, there could be no finding of equivalence, relying on Planet Bingo, LLC v. GameTech International, Inc., 472 F.3d 1338, 1345 (Fed. Cir. 2006).  Slip op. at 10.  The Court disagreed.  The Court stated, "'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."  Id. at 11.  The Court then affirmed the district court's finding of infringement under the DOE, concluding that a reasonable trier of fact could conclude, and in fact did conclude, that Exela's process is insubstantially different from the claimed process.

Exela also argued that the district court erred in concluding that the phrase "optionally topped with an inert gas . . . and placed in a closed container" indicates that the "vacuum stoppering step" was optional.  Id. at 12 (quoting Cadence, 886 F. Supp. 2d at 464).  Relying on the specification and prosecution history, Exela argued that the step was mandatory.  The Court disagreed.  As did the district court, the Court held that the plain and ordinary meaning of the term "optionally" indicated that the step was optional.  The Court also examined the specification and found nothing to imply that the invention was limited to embodiments requiring the step to be mandatory.  Similarly, the Court agreed with the district court that the prosecution history failed to clearly and unmistakably disavow the unambiguous recitation of the step being optional.  Concluding that the step was optional and not mandatory, the Court affirmed the district court's finding of infringement. 

Finally, the Court affirmed the district court's determination of nonobviousness.  Exela argued that the '218 patent was obvious over the '222 patent in view of a prior art reference.  The district court found that it would not have been obvious to combine the reference with the '222 patent because the compound disclosed in the reference process degraded by oxidation, whereas acetaminophen degrades primarily by hydrolysis.  The district court also found relevant that the claimed process was "technical[ly] difficult[]."  Id. at 16 (alterations in original) (quoting Cadence Pharm., Inc. v. Excela Pharma Scis., LLC, No. 11-733-LPS, 2013 U.S. Dist. LEXIS 166097, at *105 (D. Del. Nov. 14, 2013)).  The district court also found that secondary considerations supported a conclusion of nonobviousness.  Specifically, the district court found that Ofirmev® fulfilled a long-felt need, was a commercial success, was licensed and praised in the industry, and exhibited unexpected results.  Noting that "Exela [bore] a difficult burden . . . since the Examiner initially rejected the claims . . . for essentially the same reasons" and "patents are presumed to be valid," the Court ultimately agreed with the district court's findings and affirmed its nonobviousness determination.  Id. at 17. 

Judges: Reyna, Linn (author), Wallach

[Appealed from D. Del., Judge Stark]

This article previously appeared in Last Month at the Federal Circuit, April, 2015

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