Plaintiffs’ Local Patent Rule 3.2(b) Document Production Sufficient to Support an “Invention Date” Predating a Disclosed “Priority Date”

Applying the plain language of the District of New Jersey’s Local Patent Rules, Chief Judge Wolfson recently ruled in Mitsubishi Tanabe Pharma Corp. v. Sandoz Inc., that the plaintiffs were not precluded from asserting an “invention date” derived from their Local Patent Rule 3.2(b) disclosures that differed from the “priority date” expressly disclosed in their Local Patent Rule 3.1(f) contention disclosures.

Local Patent Rule 3.1(f) requires that infringement contentions disclose, “[f]or any patent that claims priority to an earlier application, the priority date to which asserted claim is allegedly entitled.” Local Patent Rule 3.2 governs the document production that must accompany Local Patent Rule 3.1 disclosures and Local Patent Rule 3.2(b) requires the production of “[a]ll documents evidencing the conception, reduction to practice, design, and development of each claimed invention, which were created on or before the date of application for the patent in suit or the priority date identified pursuant to L. Pat. R. 3.1(f), whichever is earlier.” An “invention date” and a “priority date” have distinct meanings in patent law. An “invention date” is the date when the inventor conceived the invention and reduced it to practice and the “priority date” is the filing date of the earliest patent application to which the patents-in-suit are entitled.

The plaintiffs’ Local Patent Rule 3.1(f) infringement contentions disclosed a priority date of “no later than July 30, 2004” and “reserve[d] the right to establish an earlier date of invention based on documents being produced contemporaneously.” The plaintiffs’ Local Patent Rule 3.2(b) document production included documents that evidenced a conception date predating the Local Patent Rule 3.1(f) priority date. Defendant Zydus Pharmaceuticals Inc. (“Zydus”) argued in its in limine motion that the plaintiffs were required to disclose earlier invention dates in their Infringement Contentions and should be precluded from asserting an earlier date at trial.

The plaintiffs argued, and the court agreed, that they complied with the plain language of both Local Patent Rule 3.1(f) and 3.2(b) because “in their June 2018 Infringement contention, Plaintiffs identified a priority date (thereby satisfying 3.1(f)) and produced documents evidencing an invention date that occurred ‘before’ that priority date (thereby satisfying 3.2(b)).”

The court also noted that Zydus should have sought discovery and not waited until the eve of trial to raise the issue because it had been on notice of the plaintiffs’ intention to assert an earlier invention date based on the plaintiffs’ expert reports and inventor deposition testimony.

Gibbons P.C. will continue to monitor and report developments in the interpretation and application of the District of New Jersey’s Local Patent Rules.

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