I find nothing more pleasing than when the parties dispute the test to be applied. Facts are always messy and disputed, but an argument about the proper test is almost always elegant. Truly it is a beauty fit for a post.
The particular test at issue in Azurity Pharms., Inc. v. Bionpharma Inc., C.A. No 21-1286-MSG (D. Del. Jan. 6, 2023) (Mem. Op.) whether new patent claims were the “same cause of action” for the purposes of claim preclusion.
The plaintiff argued that the well-worn rule that claim preclusion would apply to later patent claims if "the scope of the asserted patent claims in the two suits is essentially the same." Defendant, however, offered the novel argument that "two patent claims are 'essentially the same' if the second claim would have been obvious to one skilled in the art with knowledge of the first claim."
Judge Goldberg described apparent chain of reasoning thusly:
The parties’ divergent positions stem from the following sentence in the Federal Circuit’s SimpleAir decision: “In applying [the claim preclusion] standard to the particular context here, we conclude that claims which are patentably indistinct are essentially the same.” . . The underlined term “patentably indistinct” is also used in the doctrine of obviousness-type double patenting, where it means that “the [later] claims are obvious over the [earlier] claims.” . . . Bionpharma argues that by using ...