PTAB Estoppel & Inequitable Conduct

Inequitable conduct before the USPTO is an equitable defense to patent infringement that, if proved, bars enforcement of a patent. Thereasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1285 (Fed. Cir. 2011).  Given the increasing inventory of Final Written Decisions (FWD) in larger patent portfolios, practitioners are only now beginning to confront issues of inequitable conduct relating to agency based estoppel.  That is, if a patent owner advances a position inconsistent with a previous PTAB FWD on a patent/related patent under 37 C.F.R. § 42.73(d)(3), whether such a practice constitutes inequitable conduct. It just might.

But, for the time being, the courts’ lack of experience with the PTAB’s rule-based estoppel is benefiting patent owners.
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