A Blog About Intellectual Property Litigation and the District of Delaware


Entries for tag: Interrogatories

Another Day, Another Overbroad Interrogatory

Andrew E. Russell, Nov. 7, 2025
Interrogatories Discovery Responses

That's a miss.
Chad Stembridge, Unsplash

Yesterday, visiting Judge Murphy issued an order resolving discovery disputes in A.L.M. Holding Company v. Zydex Industries Private Limited, C.A. No. 25-255-JFM (D. Del.).

The patentee had served a very broad interrogatory:

For each Accused Product, describe all research, development, testing, and manufacturing performed from January 1, 2013 to the present, including by identifying any dates, locations, persons involved along with their roles, the results of any testing, and any Documents (by Bates number) You contend provide evidence of any of the foregoing.

D.I. 117, Ex. F at 20. The accused infringer's response was just objections and a lengthy list of documents under FRCP 33(d). Id. at 21-28.

I frequently see people draft …

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Court Again Rejects "No Later Than" Formulation for Answer to Conception Interrogatories

Andrew E. Russell, Aug. 5, 2024
Conception Date of Conception

"By careful review of literally just the face of the patent, we have determined that the conception date is no later than the 2/3/2017 filing date. You're welcome." AI-Generated, displayed with permission

I admit, sometimes I write about things because I want to be able to find them next time I need them. This is one of those posts.

As we've discussed before, most patent cases involve an interrogatory to the patentee asking for the date of conception. Patentees often give a low-effort initial response along the lines of "no later than x," where x is the date of filing or some other easy-to-identify date. Then they wait to see whether they need an earlier date, and supplement if so.

This has two benefits for the patentee: (1) it makes it hard for the accused infringer to weigh the relative merits of the prior art, because it has to hit a moving target, and (2) it's super easy, because the patentee doesn't have to review any of the materials. Thus, it's a common response.

The Court has rejected this response in the past, including the idea that "[a patentee] has no obligation to investigate whether the patent-in-suit is entitled to an earlier priority date at least until Defendant has provided its invalidity contentions." The Court in that transcript forced the patentee to actually respond to the interrogatory—making it a handy transcript for accused infringers.

But as of today we have ...

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The Court: Broad, General Interrogatories Merit Only Broad, General Answers

Andrew E. Russell, Aug. 28, 2020
Interrogatories Discovery

Judge Burke yesterday unsealed a lengthy opinion addressing a range of discovery disputes in a pending trade secret litigation.

In one instance, plaintiff sought to force a further response to a broad interrogatory, and complained that Defendant's broad answer omitted important time periods. The interrogatory asked:

[D]escribe in detail the stage of R&D, design, documentation, clinical work, marketing and/or sales of the [relevant product] at the time [Defendant] or anyone on behalf of [Defendant] was in first contact with any Former [Plaintiff] Employee . . . .

Judge Burke denied the request, noting that the time periods Plaintiff complained about were from before the alleged trade secret theft, and therefore it was not clear why they were relevant. He also …

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