We keep writing about how hard it is to win a motion to strike in D. Del., which is generally true. That said, it's still possible to get late-disclosed theories and evidence excluded, especially when there's no good explanation for the delay.
Yesterday afternoon, one plaintiff learned that lesson the hard way. As often happens, the plaintiff argued that the defendant's expert raised new opinions on motivation-to-combine in his reply report.
But instead of moving to strike (or seeking leave to submit a sur-rebuttal report, or dealing with the issue during expert depositions...), the plaintiff simply waited until summary judgment briefing. There, it submitted a rebuttal declaration from its own expert in support of its answering brief on invalidity. As Judge Andrews put it:
Plaintiff simply lay in wait until the middle of summary judgment briefing to respond to McNair’s “new” opinions made nearly two months earlier.
Although the prejudice caused by this late disclosure was arguably curable ("perhaps by allowing more deposition of [the plaintiff's expert] or allowing a supplemental expert report by [the defendant's expert]"), Judge Andrews found that additional expert discovery "would do nothing to mitigate the prejudice of interfering with the summary judgment briefing."
Plaintiff’s failure to reasonably explain its choice not to timely disclose its new invalidity opinions, and the prejudice to Defendant since it has moved well past expert discovery, justify the exclusion of the portions of Dr. Madisetti’s Declaration that opine on those theories.