Supernus Pharms., Inc. v. TWi Pharms., Inc.

The appellate court affirmed the trial court’s findings of infringement and validity, and that its limited reliance on a prior case concerning the same asserted patents but a different defendant was proper.

September 06, 2018

GENERICally Speaking

Case Name: Supernus Pharms., Inc. v. TWi Pharms., Inc., Fed. Cir. No. 2017-2513, 2018 U.S. App. LEXIS 25271 (Fed. Cir. Sept. 6, 2018) 

Drug Product and Patent(s)-in-Suit: Oxtellar XR® (oxcarbazepine); U.S. Patents Nos. 7,722,898 (“the ’898 patent”), 7,910,131 (“the ’131 patent”), and 8,821,930 (“the ’930 patent”)

Nature of the Case and Issue(s) Presented: Oxtellar XR is an extended-release formulation of oxcarbazepine, which is used to treat partial epilepsy seizures in adults and children over the age of six. The asserted patents share a common specification and the same inventors, and are generally directed to controlled-release formulations of oxcarbazepine with enhanced bioavailability. At Markman, the district court construed the claim term “at least one agent that enhances the solubility of oxcarbazepine” (the “solubility agent limitation”) as “an agent, other than oxcarbazepine, that enhances the solubility of oxcarbazepine, which agent cannot also serve as the sole matrix-forming polymer … or the sole release promoting agent … in claim 1.” The district court construed the claim term “homogeneous matrix” as a “matrix in which the ingredients or constituents are uniformly dispersed.” Thereafter, the district court decided a related case, Supernus Pharms., Inc. v. Actavis Inc., 13-cv-4740-RMB-JS (D.N.J. Feb. 5, 2016) (“Actavis”), which involved the same patents, holding that the asserted patents were not invalid and infringed.

Supernus then sued TWi alleging infringement of the asserted patents based on TWi’s filing of its ANDA. After a bench trial, the district court concluded that the asserted patents were not invalid and would be infringed by TWi’s proposed generic version of Oxtellar XR. TWi appealed the district court’s judgment, arguing that the district court erred by: (i) giving its decision in a related case de facto preclusive effect; (ii) concluding the proposed product would infringe certain claim limitations; and (iii) concluding that the asserted patents were not invalid as indefinite or for lack of written description. The Federal Circuit affirmed.

Why Supernus Prevailed: Preclusive Effect. The Federal Circuit first addressed TWi’s argument that the district court improperly relied on its findings and conclusions from Actavis when making its determinations. The Federal Circuit found no error, finding that: (i) the district court relied on Actavis only to the extent the records were similar or the parties had agreed to be bound by a conclusion in Actavis; (ii) the district court based its infringement determination solely on tests and evidence admitted in the TWi case; and (iii) the district court referenced Actavis only to the extent that the records in the two cases were the same.

Infringement. TWi argued that neither the solubility-agent limitation nor the homogenous-matrix limitation was infringed. With respect to the solubility-agent limitation, TWi’s argument turned on how the patent specification defined “enhanced” and “non-enhanced” formulations. TWi argued that, according to the specification, “enhanced” formulations contained a release promoter, solubility agent, or both. A “non-enhanced” formulation, according to TWi, contained neither a release promoter nor a solubility enhancer. TWi tied its argument to the following statement in the specification: “improvements were made to the formulations by incorporating solubility enhancers and/or release-promoting excipients (such formulation[s] are referred to as enhanced formulations).

TWi argued that the district court incorrectly interpreted the term “and/or” to mean solely “and,” where it should mean “and” or “or.” Under TWi’s theory, the accused agent in its proposed formulation could not satisfy the solubility-agent claim limitation because the specification characterized an example formulation containing said accused agent but lacking a release-promoting agent as “non-enhanced.” In other words, because a “non-enhanced” formulation could contain neither a solubility agent nor a release-promoting agent, TWi contended that the specification effectively admitted the accused agent was not a solubility agent. The Federal Circuit disagreed and affirmed the district court’s interpretation, that an “enhanced” formulation must have both a release-promoting agent and a solubility agent. Thus, a “non-enhanced” formulation may contain either a solubility agent or a release-promoting agent. The court explained that the fact that the example “non-enhanced” formulation contained the accused agent did not preclude a finding that the accused agent was a solubility agent. The Federal Circuit thus found that the district court did not err in finding that the statement in the specification did not amount to an admission of non-infringement.

TWi further challenged the district court’s finding that its proposed product infringed the “homogeneous matrix” limitation, arguing that the district court changed its construction of the term in its post-trial decision from “matrix in which the ingredients or constituents are uniformly dispersed” to “no localization of constituents.” The Federal Circuit disagreed with TWi, reasoning that the district court was merely clarifying what was already inherent in its construction. In its claim-construction decision, the court reasoned that homogeneous matrix was not directed to a degree of uniformity, but instead was meant to differentiate Supernus’s invention, which had all components of the matrix in the tablet core, from prior-art references where some components were located only in the coating. Thus, according to the district court, “uniformly dispersed” necessarily implicated an absence of localization. The Federal Circuit therefore found that the district court did not err in finding infringement of the “homogenous matrix” limitation.

Indefiniteness/Lack of Written Description. Despite TWi’s arguments to the contrary, the Federal Circuit found that the specification, prosecution history, and expert testimony supported the district court’s conclusion that the term “homogenous matrix” was not indefinite and did not lack written-description support.

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