Product Of IPR Estoppel: A District Court Split

• Published date: 02 August 2023
• Law Firm: Baker Botts
• Author: Lance J. Goodman

Inter partes review (IPR) is an administrative trial proceeding developed under the American Invents Act (AIA) and is conducted at the Patent Trials and Appeals Board (PTAB) to review the patentability of one or more claims in a patent only on a ground that could be raised under ' 102 or 103, and only on the basis of prior art consisting of patents or printed publications. 35 U.S.C. ' 311. Yet filing an IPR comes with a trade-off, an IPR proceeding has the benefit of efficiency and success, but the underlying statute restricts the ability for a patent challenger to raise challenges to patents in district courts that have been or reasonably could have been raised in the IPR proceeding. As such, a defendant in patent litigation needs to carefully consider whether to challenge patent validity in the district court or in an IPR proceeding. This article analyzes how district courts have restricted (or not) invalidity proceedings in view of a co-pending or previously litigated IPR proceeding.

The estoppel provision of the inter partes review (IPR) statute ensures that a party is estopped from being able to relitigate grounds that have been or could have been reasonably raised during a district court proceeding. The estoppel is triggered upon issuance of a final written decision from the Patent Trials and Appeals Board ("PTAB"). Yet, in some circumstances, parties have willingly stipulated to the estoppel provision in order to incentivize the board to institute a petition with what has become known as a Sotera stipulation. There have been numerous issues that the courts have dealt with when applying the IPR estoppel statute and related Sotera stipulation.

One issue that has emerged is one of strategic importance'what happens when the patent challenger relies on printed prior art (patents or publications) in the IPR proceeding, and therefore is estopped from relying on that printed publication prior art in a parallel district court dispute, but wants to rely on a system or device as prior art in that parallel district court proceeding? Many district courts have approached this issue differently, resulting in a split even within some districts, which has left litigants struggling to formulate their patent defense strategies in situations in which the printed prior art fully covers or describes a prior art system.

Background

The estoppel statute states:

The petitioner in an inter partes review of a claim in a patent under this chapter that results in a final written decision under section 318(a), or...