Astellas US LLC v. Hospira, Inc.

Case Name: Astellas US LLC v. Hospira, Inc., No. 2022-1878, 2022 WL 17998229 (Fed. Cir. Dec. 30, 2022) (Circuit Judges Dyk, Reyna, and Cunningham presiding; Opinion by Dyk, J.) (Appeal from D. Del., Connolly, J.)

Drug Product and Patent(s)-in-Suit: Lexiscan® (regadenoson); U.S. Patents Nos. 8,106,183 (“the ’183 patent”), RE47,301 (“the ’301 patent”), and 8,524,883 (“the ’833 patent”)

Nature of the Case and Issue(s) Presented: Astellas sued Hospira alleging that Hospira’s ANDA to market Form G regadenoson infringed three patents covering Form A regadenoson, a monohydrate form of regadenoson used to increase blood flow to mimic a cardiac stress test. Astellas alleged that a third party inadvertently creates Form A regadenoson during production of an intermediate product that Hospira then incorporates into its final ANDA product.

Before trial, Hospira amended its ANDA (reflecting changes to the third party’s DMF), undermining Astellas’s infringement theory. So Astellas developed and tried to present a new, previously unasserted theory (e.g. that Hospira’s own process, in addition to the third party’s, created Form A regadenoson). Hospira moved to strike the new theory, and the district court granted the motion. Astellas tried its original theory and lost. The Federal Circuit affirmed.

Why Hospira Prevailed: Because Astellas’s new infringement theory relied on documents produced more than a year before Astellas disclosed its theory, the district court did not abuse its discretion in determining that it was untimely. The court noted that “[t]his is not a case where Astellas relied on new information disclosed in the ANDA amendment to craft a new theory of infringement. Instead, Astellas simply decided that the ANDA amendment would make it harder to prove its original infringement theory and decided to try a new theory related to a process not changed by the amendment.” The court deferred to the district court’s discretion in managing its case.