Entresto® (sacubitril/valsartan)
Case Name: Iin re Entresto (sacubitril/valsartan) Patent Litigation (Novartis Pharms. Corp. v. MSN Labs. Private Ltd.), Civ. Nos. 20-md-2931-RGA, 25-cv-81-RGA, 2026 WL 161377 (D. Del. Jan. 21, 2026) (Andrews, J.)
Drug Product and Patent(s)-in-Suit: Entresto® (sacubitril/valsartan); U.S. Patent No. 8,101,659 (“the ’659 patent”)
Nature of the Case and Issue(s) Presented: In a previous case, the court entered final judgment that MSN’s ANDA product infringed claims 1-4 of the ’659 patent. In the current case, Novartis accuses MSN of infringing the same patent. Novartis moved to preclude MSN from relitigating claim construction, for summary judgment on MSN’s Third Affirmative Defense (invalidity) and Second Counterclaim (invalidity), partial summary judgment on Novartis’ infringement claim, and partial summary judgment on MSN’s First Counterclaim (non-infringement) on the basis of issue preclusion and claim preclusion. The court granted Novartis’s motion.
Why Novartis Prevailed: Issue preclusion barred the parties from relitigating claim construction. The “wherein” clause was construed in a previous case between the parties. Where a determination of the scope of patent claims was made in a prior case, and the determination was essential to the judgment there on the issue of infringement, there is collateral estoppel in a later case on the scope of such claims, i.e., the determined scope cannot be changed. Here, the identical claim construction issue was previously adjudicated, the claim construction of the term was actually and fully litigated, the claim construction was necessary to the resolution of the prior case, the defendants were fully represented in the prior case, and considerations of fairness do not prohibit issue preclusion.
Summary judgment of validity granted. MSN argued that claim preclusion did not apply in this case because invalidity is not a claim, but rather a defense to which claim preclusion does not attach. Here, there was a final judgment in the prior case, the parties in the current case were all parties to the prior case or in privity with a party, both the current case and the prior case involve the same accused product, MSN’s ANDA product, and both cases involve the ’659 patent, and the accused products are essentially the same. Therefore, nothing prohibits claim preclusion from applying to validity in this case and Novartis’s issue preclusion argument is moot.
Summary judgment of infringement by MSN’s ANDA product is granted. MSN argued that infringement under 35 U.S.C. § 271(a–c) was not at issue in the prior case. Technically correct because infringement was found in the prior case under 35 U.S.C. § 271(e)(2), MSN’s argument is “irrelevant.” There was no dispute that both the current and the prior cases involved an issue of whether MSN’s ANDA product met the claim elements of the ’659 patent, and that’s the only patent for which Novartis seeks summary judgment. “Although different underlying infringement actions were in dispute in the prior case, the infringement claims in both cases depend on whether MSN’s ANDA product meets the claim elements of the ’659 patent.” MSN argued that the final judgment of infringement was not actually litigated because it was based on a stipulation that was not binding in the current case. But the Federal Circuit has held that a stipulated judgment in a patent case can serve as the grounds for issue preclusion. Moreover, the stipulation had forward looking language indicating the parties’ intent for the agreement to apply to future conduct. MSN also argued infringement was not actually litigated because Novartis did not spend a considerable amount of effort litigating that issue. But Novartis’ complaint alleged that MSN’s ANDA product infringed the ’659 patent, and for nearly two and a half years, it was an issue that Novartis had to prove to make its case. Only after Novartis submitted an expert report on infringement did MSN enter into a stipulation of infringement. Finally, MSN argued that infringement was not litigated after the Federal Circuit’s opinion. But the court found that the Federal Circuit’s decision did not change the law. “There is nothing new to litigate. Any arguments related to whether MSN’s ANDA product met the claim elements of the ’659 patent were available to make in the prior case.”
