What Are the Priority Date, Patent Term, and Effective Filing Date of a Patent: The Roles of Specific Reference, Incorporation by Reference, and Claim Support

A recent Federal Circuit decision demonstrates that for priority claims and patent term, the phrase “specific reference” is key. For example, amongst three related applications, to get the benefit of priority of an earlier U.S. patent application 1, application 3 in a priority claim has to have a “specific reference” to earlier application 1. A mere priority claim in application 3 to application 2, even though application 2 specifically “incorporates by reference” application 1, is not sufficient to allow application 3 to rely on the filing date of application 1. Rather, the priority chain is broken between applications 2 and 1, leaving application 3, at best, with a priority date of application 2 for purposes of patentability.

Furthermore, a recent district court decision highlights that there must be nothing more than a “specific reference” in the later patent application to the earlier patent application to start the patent clock with the date of the earlier patent application. And, whether or not any claim in the later application is entitled to priority in the earlier application for patentability purposes requires “specific reference” to the earlier application. In this article, Finnegan attorneys analyze two recent cases for practical lessons when (1) drafting and prosecuting patent applications and (2) analyzing issued U.S. patents in the context of freedom to operate and/or due diligence.

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*Stacy Lewis is a law clerk at Finnegan.