Case Name: Biogen Int’l GmbH v. Amneal Pharmaceuticals LLC, Civ. No. 17-823 (MN), 2020 WL 5549084 (D. Del. Sept. 16, 2020) (Noreika, J.)

Drug Product and Patent(s)-in-Suit: Tecfidera® (dimethyl fumarate (“DMF”) delayed-release capsules); U.S. Pat. No. 8,399,514 (“the ’514 patent)

Nature of the Case and Issue(s) Presented: Tecfidera is an FDA-approved drug indicated for relapsing forms of multiple sclerosis (“MS”). Biogen, the NDA holder for Tecfidera, sued several defendants alleging infringement of the ’514 patent based on the filing of ANDAs seeking approval to market generic versions of Tecfidera. At trial, Defendants contended that claims 1-4, 6, 8-13, 15, and 16 were invalid for lack of adequate written description, lack of enablement, improper inventorship and derivation, obviousness, and anticipation. Biogen also sued Mylan in the Northern District of West Virginia (N.D.W.V.) for infringement of the ’514 patent based on Mylan’s submission of an ANDA for approval to market a generic version of Tecfidera. After a bench trial, and before the Delaware court issued its opinion, the N.D.W.V. found that Mylan had proven by clear and convincing evidence that the asserted claims of the ’514 patent were invalid for lack of adequate written description. Pursuant to the Delaware court’s order, Defendants in the Delaware case submitted supplemental post-trial briefs on the issue of whether the N.D.W.V. judgment of invalidity should apply to the Delaware case under the principles of collateral estoppel. The court ruled that it did.

Why Defendants Prevailed: The claims of the ’514 patent are generally directed to treating MS with about 480 mg per day of DMF, monomethyl fumerate (“MMF”), or mixtures thereof. The court, however, noted that the specification contained little discussion of using these fumerates to treat MS and the 480 mg dose is only mentioned in one paragraph.

The N.D.W.V. found that the asserted claims lacked written description because the specification was not specific to the treatment of MS, but instead related to treating neurodegenerative diseases more broadly, and that the ’514 patent did not link a 480 mg dose to treating MS. Thus, according to the N.D.W.V., the ’514 patent did not convey that the inventors were in possession of their claimed inventions as of the patent’s priority date.

Next, the court turned to whether collateral estoppel should apply. First, the court found an “identity of issues” between this case and the N.D.W.V. case, explaining that under Federal Circuit law, once the claims of a patent are held invalid as against one alleged infringer, others who are accused of infringement may reap the benefit of that decision under collateral estoppel. Second, the court addressed found that the invalidity issue was “actually litigated” in the N.D.W.V. because the parties proceeded through a bench trial limited to the issue of lack of written description after which a final judgment of invalidity was entered. Third, the court held that there was no dispute that the invalidity issue was “necessary for the N.D.W.V. judgment.” Finally, the court found that Plaintiffs did not demonstrate that they were deprived of a full and fair opportunity to defend against Mylan’s invalidity challenge in the N.D.W.V.

The court next addressed “other considerations” raised by Plaintiffs. Plaintiffs argued that the court should decline to apply collateral estoppel, an equitable doctrine, because of the “advanced stage of the proceedings and the unusual circumstances that required Biogen to litigate in parallel in both West Virginia and Delaware.” Plaintiffs argued that applying collateral estoppel was not in the interest of “judicial efficiency and fairness” because duplicative litigation had already occurred given that both cases proceeded on parallel tracks and trial occurred at roughly the same time in both cases. The court disagreed. Considerations of justice and equity are not standalone considerations that can be used to avoid collateral estoppel when the four requirements are otherwise met. Further, the court disagreed with Plaintiffs’ argument that judicial fairness and efficiency would be served by declining to apply collateral estoppel because, if the N.D.W.V.case was overturned on appeal, the parties would have to come back to the Delaware district court for a decision on the remaining defenses. The court explained that the N.D.W.V. conducted a careful analysis of the ’514 patent and its written description issues. For the Delaware court to decide issues anew would be “an exercise in judicial inefficiency and disregard for a judgment that should be afforded preclusive effect.”