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Chief Judge Stark issues claim construction in ANDA litigation, finds certain terms indefinite


In a recent Memorandum Opinion, Chief Judge Leonard P. Stark issued a claim construction construing claim terms across seven of the eight patents-in-suit in this ANDA litigation. Forest Laboratories, Inc. et al. v. Teva Pharmaceuticals USA, Inc. et al., C.A. Nos. 14-121, 14-200, 14-508, 14-686, 14-1058, 14-1271-LPS (D. Del. Jan. 5, 2016). Among the terms construed, Judge Stark found two terms indefinite. First, Judge Stark found the term “change in memantine concentration as a function of time (dC/dT) that is less than 50% that of an immediate release dosage form comprising the same dose of memantine as the composition” indefinite. Judge Stark explained that “[a]s indicated in the claims, memantine concentration must be observed ‘as measured in a single-dose human PK study.’” Id. at 16. Judge Stark found that “[a] person of ordinary skill in the art would not know, with reasonable certainty, which ‘human PK study’ on which to rely when considering whether a formulation of memantine might infringe the [patents at issue].” Id. Judge Stark explained that the patents at issue “provide[] no guidance, other than non-limiting examples, regarding which concentration profile (or set of profiles) should be used when assessing potential infringement.” Id. at 16-17. Indeed, as Judge Stark noted, “[t]he specifications of the [patents at issue] do not disclose any human PK study. Rather, they disclose memantine concentration data generated from computer simulations.” Id. at 17. Judge Stark also found the term “change in plasma concentration as a function of time (dC/dT) in a defined time period of 0 to 6 hours after administration … that is less than about 50% of the dC/dT provided by the same quantity of an immediate release form of memantine in said defined time period” indefinite for the same reasons discussed above with respect to the “memantine concentration…” term. Id. at 20. Specifically, “the ‘human PK study’ limitation (which is present in all of the claims containing this term) does not give a POSA the required ‘reasonable certainty.’” Id. at 20.

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