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District Court Denies Motion to Compel Production of Inventor Emails in Patent Infringement Case

In a recent discovery dispute in a patent infringement case, the district court denied the defendant’s motion to compel the plaintiff to produce certain inventor emails that were withheld on the basis of the work product doctrine. The key issue was whether the plaintiff demonstrated that the emails, exchanged between the two inventors of the asserted patents from 2016-2018, were prepared in anticipation of litigation. The litigation ultimately commenced in February 2022.

The district court acknowledged that evidence pointed to by both sides benefitted their respective positions–the defendant highlighted facts suggesting the inventors’ work was not in anticipation of litigation, while the plaintiff provided contrary evidence. Ultimately, the district court found the plaintiff’s showing sufficient to meet its burden and justify the work product protection.

Key evidence cited by the district court included:

  1. An inventor’s testimony that he began investigating potential infringement in November 2015 with the assistance of outside counsel.
  2. The inventor provided information to outside counsel from 2016-2020 to assess possible infringement.
  3. Starting November 2015, the inventor implemented measures to preserve documents related to the patents and defendant.
  4. Testimony from the outside attorney that he had previously advised the plaintiff about potential litigation involving the patents at issue.

Notably, while four to six years elapsed between the initial anticipation of litigation and the eventual filing of the complaint, the district court emphasized there is no firm rule that work product cannot apply beyond a set timeframe pre-filing. As the district court explained, “so far as the Court can tell, there is no hard and fast rule that an “anticipation of litigation” showing cannot be made after a set amount of time has passed. See First Quality Tissue, LLC v. Irving Consumer Prods. Ltd., Civil Action No. 19-428-RGA, D.I. 142 at 10 (D. Del. Oct. 9, 2020) (Stover, S.M.) (concluding that the plaintiff had demonstrated that certain documents were generated in anticipation of litigation, where a showing had been made that litigation was anticipated as of May 2013, even though suit was not filed until March 2019, and noting that “[a]nticipation of litigation is not limited to a particular amount of time prior to filing suit”); see also Lambeth Magnetic Structures, LLC v. Seagate Tech. (US) Holdings, Inc., Civil Action No. 16-538, Civil Action No. 16-541, 2018 WL 466045, at *1-4 (W.D. Pa. Jan. 18, 2018) (finding that the inventor’s communications with his colleagues regarding reverse engineering from October 2008 through March 2014, some of which preceded the litigation by seven years, were protected by the work product doctrine, as the “entire basis” for the communications “was to prepare for litigation by determining which products contained technologies potentially infringing the ‘988 patent”).

Accordingly, the district court denied the motion to compel.

Oasis Tooling, Inc. v. Siemens Industry Software, Inc., Case No. 1-22-cv-00151 (D. Del. May 6, 2024)


The authors of are patent trial lawyers at Jeffer Mangels Butler & Mitchell LLP. For more information about this case, contact Stan Gibson at 310.201.3548 or