For years now I've been working on a double-dutch rhyme for the Pennypack factors. A Miss Merry-Mack for elderly nerds, if you will. It shall be my crowning achievement as a Delaware lawyer, and the work that I shall be remembered for.
But until that Glorious work is unveiled at the 2038 Bench and Bar conference, I can present you with just another Pennypack opinion for your portfolio. This one follows the recent trend of a slightly harsher application of the factors.
The Plaintiff in Agilent Techs., Inc. v. Axion BioSystems, Inc., C.A. No. 23-198-CJB, D.I. 456 (D. Del. Nov. 25, 2025) had responded to an interrogatory asking for which elements were not anticipated or rendered obvious by the references in the defendant's contentions. That response had included a general objection that the invalidity contentions lacked enough detail to show that any element was met, and also by specifically calling out several missing elements.
Come expert reports, Plaintiff's expert referenced several elements not specifically called out in the earlier responses as missing. Defendant moved to strike references to these other elements and Judge Burke granted the motion:
Plaintiff never comes up with a good explanation for how things went down as they did. For example, nowhere in Plaintiff's briefing does it actually come out and say "Yes, it is true, we did not include the limitations at issue in our prior discovery responses." Plaintiff just kind of... ignores that part. And Plaintiff never explains why it was that it could not have identified the limitations at issue as being missing from the references earlier in the case—i.e., it never articulates why something in Defendant's expert's opening report would have served, for the first time, to suggest to it that the limitations at issue weren't found in Ehret 1997 and Keese. Instead, Plaintiff blames Defendant for where we are, by repeatedly asserting that Defendant's invalidity contentions were wanting. But if Defendant's invalidity contentions were problematically vague, then Plaintiff should have gone to the Court during fact discovery and gotten the Court to order Defendant to say more. What a party in Plaintiff's shoes can't do is fail to complain to the Court about such contentions, and then try to use those purportedly-wanting contentions as a "get out of jail free card" to allow it to spring clearly new positions on its adversary later in expert discovery.
Id.
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