On Dec. 30, 2022, Federal Circuit affirmed District court which excluded the new infringement theory put forth by Astellas.

Plaintiffs (Gilead / Astellas) sued Defendant (Hospira) for infringement as Hospira filed ANDA to market generic version of LEXISCAN® (regadenoson) injection. Asserted patents are 8,106,183; RE47,301; and 8,524,883 which cover monohydrate Form-A of regadenoson. Astellas’s theory (intermediate theory) was that Form A regadenoson, occurred inadvertently in the production process for an intermediate product made by a third party (Curia) and incorporated by Hospira into its final product. Before trial, Hospira amended its ANDA, allegedly making it more difficult for Astellas to prove its original infringement theory. Astellas then sought to present a new and previously unasserted infringement theory (compounding theory). The district court found this new theory to be untimely
and granted Hospira’s motion to strike the new infringement contentions. The trial went forward on Astellas’s original infringement theory, and the district court found that Hospira did not infringe. Astellas appealed
only the district court’s grant of the motion to strike its new infringement theory. You can read the decision summary “here” on this blog.

During appeal, Astellas first argued that its new compounding infringement theory was not untimely. Court said that Astellas did not reveal its new theory until October 2021, close to a year after the original fact discovery period closed (October 2020), months after the original expert discovery period closed (April 2021), and shortly after supplemental fact discovery closed. Because this theory was based on documents produced to Astellas in August 2020, Astellas could have raised this theory during the original period of discovery. There was no reason, other than
Astellas’s own litigation choices, that the compounding infringement theory could not have been asserted earlier. Therefore, district court did not abuse its discretion in determining that Astellas’s supplemental infringement
contentions and expert evidence were untimely.

Astellas secondly argued that its new evidence and infringement theory, even if untimely, should not have been excluded. Court said that Pennypack factors are generally considered by Third Circuit for this matter. Hospira
was clearly surprised by the new infringement theory that was unrelated to the ANDA amendment and had no
reason to suspect that Astellas would seek to assert the new compounding infringement theory. During the original
discovery period, Astellas’s expert explicitly stated that he was not offering an opinion as to whether the compounding process causes infringement. To be sure, the trial date could have been moved yet again, but the trial date had already been postponed for over six months to enable the supplemental discovery and further delay would have prejudiced some other defendants in the case by effectively extending the presumed generic launch date. The district court correctly concluded that Hospira would likely be prejudiced by the introduction of the compounding infringement theory at this late stage.