It is becoming increasingly apparent that inter partes review ("IPR") petitioner estoppel after the Patent Trial and Appeal Board ("PTAB") issues a final written decision can have broad consequences on a petitioner's invalidity defenses in civil actions. This article will examine the practical impact of IPR estoppel and discuss strategic considerations for IPR parties involved in parallel district court or International Trade Commission ("ITC") actions. This article will address four main questions : (1) when and how a petitioner can use paper prior art in a § 102 or 103 defense after an unsuccessful IPR; (2) how IPR estoppel may impact invalidity defenses based on product prior art; (3) how IPR estoppel may impact a "known or used" invalidity defense; and (4) whether IPR estoppel applies when a petitioner prevails in an IPR. In limited circumstances, IPR petitioners may be able to pursue printed publication invalidity theories in parallel litigation after a PTAB final written decision. Yet, at the same time, IPR petitioners may face previously unexpected limitations on product prior art theories in parallel litigation after a PTAB final written decision.
Originally Published by Chicago-Kent Journal of Intellectual Property
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