The USPTO issued guidance on the standard for addressing indefiniteness in AIA trial proceedings.  The PTAB will apply the Nautilus standard in AIA trial proceedings which is the same standard used by district courts and the ITC.

As background, the USPTO historically applies the standard articulated in In re Packard, 751 F.3d 1307 (Fed. Cir. 2014) for assessing indefiniteness in ex parte patent examination.  District courts, on the other hand, assess indefiniteness under the standard articulated by the Supreme Court in Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898 (2014).  In 2018, the PTAB changed the claim construction standard used in AIA trial proceedings from the standard used in ex parte prosecution (broadest reasonable interpretation) to the standard applied in district courts and the ITC (Phillips).  In the wake of this change, the PTAB has noted confusion as to whether indefiniteness in AIA trial proceedings should be assessed under Nautilus or Packard.  Some parties in AIA trial proceedings continue to make arguments under either or both standards.

In a Memorandum issued on January 6, 2021, the USPTO clarified that the PTAB will follow the Nautilus indefiniteness standard in AIA trial proceedings.  The USPTO explained that "[b]ecause the office's claim construction standard in AIA post-grant proceedings now aligns with that used by courts in a civil action, ... the office's approach to indefiniteness in AIA post-grant proceedings should likewise align with that used by the courts...."  The USPTO also noted that "[a]s with the claim construction standard, aligning the indefiniteness approach in AIA post-grant proceedings will promote consistency and efficient decision making...."

Indefiniteness issues can arise in various contexts in AIA trial proceedings.  Petitioners in a post-grant review (PGR) proceeding, for example, can challenge the patentability of a claim based on indefiniteness.  Such outright indefiniteness challenges are not available to petitioners in inter partes review (IPR) proceedings.  However, indefiniteness can still be at issue in IPRs, for example, when dealing with claim construction and motions to amend.  Petitioners and patent owners should be aware of the PTAB's application of Nautilus when considering issues of indefiniteness.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.