On January 6, 2021, the United States Patent and Trademark Office (“USPTO”) published a Memorandum that changed the indefiniteness analysis under 35 U.S.C. §112 that the Patent Trial and Appeal Board (“PTAB”) applies in post-grant proceedings under the America Invents Act (“AIA”) so that it conforms with the standard that the district courts apply, i.e., based on the U.S. Supreme Court’s Nautilus decision.¹ Before now, the PTAB and district courts have analyzed the indefiniteness of a claim using two different legal standards, which were generally referred to as the Packard and Nautilus standards, respectively.^2,3 The Memorandum was spurred by the USPTO’s 2018 decision to align the claim construction standard used in AIA post-grant proceedings with that of the district courts, thus shifting the PTAB from using the broadest reasonable interpretation (“BRI”) standard to the district courts’ Phillips standard.⁴ The Memorandum stated that it decided to also change the indefiniteness standard because, in part, “indefiniteness questions are generally considered as part of the claim construction process.”⁵ Thus, the USPTO’s decision to align the indefiniteness standards in AIA post-grant proceedings with those of the district court may resolve “confusion as to whether Nautilus or Packard applies.”⁶ The Memorandum explained that “the rule change promotes consistency and efficiency between coordinate branches of the government that analyze the same claims in co-pending proceedings.”⁷

Indefiniteness is governed by 35 U.S.C. § 112, second paragraph (pre-AIA) or 112(b) (post-AIA). Both provisions are nearly identical and the AIA version states that “[t]he specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.”⁸

In 2014, the Supreme Court issued the Nautilus decision, which set a revised standard for determining whether a patent claim is invalid for being indefinite.³ Under Nautilus, a “patent is invalid for indefiniteness if its claim, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”³ At the time, the USPTO was analyzing indefiniteness using the prior Packard standard for both prosecution and AIA post-grant proceedings.⁹ Under Packard, a claim is indefinite “when it contains words or phrases whose meaning is unclear.”² After Nautilus, the district courts followed the Supreme Court’s standard while the USPTO continued to use the Packard standard for determining indefiniteness; the USPTO nonetheless recognized that there were fundamental differences between its approach and the district court’s approach.¹⁰

In 2018, the USPTO revised the claim construction standard used in post-grant proceedings to align with the standard used by the district courts.¹¹ The PTAB was using the BRI standard for claim construction in post-grant proceedings, while the district court was using the Phillips standard.¹² Under the BRI standard, “claims must be given their broadest reasonable interpretation in light of the specification.”¹³ Under Phillips, the claims are given a narrower interpretation, i.e., “the meaning that the term would have to a person of ordinary skill in the art in question at the time of invention.”¹⁴

As the question about whether a claim is indefinite is often linked to claim construction, the PTAB and district courts were thus using the same Phillips standard for claim construction, but differing standards for indefiniteness, namely Packard versus Nautilus, respectively. As such, the Memorandum noted that confusion arose as to which indefiniteness standard should be used by the PTAB.¹⁵ Further, the Federal Circuit had declined to decide which standard applies in the post-grant review process.¹⁶

The Memorandum aligns the indefiniteness standard between the PTAB and district courts, such that both will now be using the same Nautilus standard for indefiniteness. Notably, the USPTO’s Memorandum does not affect the USPTO’s approach to indefiniteness outside of the AIA post-grant proceeding context.¹⁷ However, substitute claims under any proceeding may be challenged as indefinite.¹⁸

The Memorandum stated that it will “lead to greater uniformity and predictability, improve the integrity of the patent system, and help increase judicial efficiency” by “eliminating the differences between indefiniteness approaches used in the district courts and before the [PTAB] in AIA post-grant proceedings.”¹⁹