In Senju Pharmaceutical Co., Ltd., et al. v. Apotex Inc., et al., C.A. No. 11-1171-SLR (D. Del.), Judge Robinson dismissed plaintiffs’ claims of infringement for failure to state a claim where the allegations were asserted against the same defendants and based on the same patent and same ANDA filing that the Court had ruled upon in a prior litigation. Id. at 1. In that prior litigation, plaintiffs filed suit against defendants for infringement of the patent at issue based on defendants’ ANDA filing. Id. at 1. At the conclusion of that case, the Court entered final judgment against plaintiffs, invalidating the asserted claims of the patent at issue as obvious. Id. at 2-3. However, while that prior litigation was still pending, without notifying the Court, plaintiffs initiated and were engaged in reexamination proceedings involving the same patent at issue. Id. at 1. Following the reexamination proceedings, plaintiffs then filed the instant litigation against defendants alleging infringement of those “new” claims of the patent at issue that were “added or amended” during reexam. Id. at 1. In response, defendants moved to dismiss the instant action based on the doctrine of res judicata or claim preclusion. Id. at 6. Specifically, defendants argued that dismissal was proper because “the claims of the current lawsuit are precluded” by the judgment against the plaintiffs in the prior litigation. Id. at 6. The Court agreed. Id. at 6. Citing both Third Circuit and Federal Circuit authority, the Court noted that “[c]laim preclusion bars any new legal claim based on the same cause of action previously asserted” and that “[e]ach patent, not patent claim, gives rise to an independent and distinct legal claim or cause of action.” Id. at 7 (emphasis in original). In its analysis, the Court concluded that in the instant litigation the plaintiffs “are alleging infringement by the same proposed product that was at issue in the first litigation” and that “[plaintiffs] could have asserted the equivalent of the new and amended claims in the first litigation.” Id. at 8-9. The Court held that the “reexamination of the patent-at-issue did not create a new cause of action against the same previous defendant and accused product and reasoned that “[a]llowing this case to go forward would open the door to relitigation of a matter that has already been decided on the merits.” Id. at 11.