One requirement of patent law is that a patent’s “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.” 35 U.S.C. § 112(b). The aforementioned is the basis for indefiniteness challenges to patent claims, which can be the subject of various proceedings before the Patent Trial and Appeal Board (PTAB) of the United States Patent and Trademark Office (USPTO), including in post-grant proceedings, and also patent litigation before the federal district courts.
Until recently, the PTAB and district courts have analyzed indefiniteness under two different legal standards, which were generally referred to as the Packard and Nautilus standards, respectively. Under Packard, a claim is indefinite “when it contains words or phrases whose meaning is unclear.” In re Packard, 751 F.3d 1307, 1310 (Fed. Cir. 2014). In contrast, 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.” Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014).
On January 6, 2021, the USPTO ended the use of different indefiniteness standards in post-grant proceedings, publishing a Memorandum that clarified that the PTAB shall follow Nautilus in America Invents Act (AIA) post-grant proceedings. See USPTO, Approach to Indefiniteness under 35 U.S.C. § 112 in AIA Post-grant Proceedings (“Memorandum”) (Jan. 6, 2021), https://www.uspto.gov/sites/default/files/documents/IndefinitenessMemo.pdf. The USPTO did this after recognizing that having two different legal standards led to confusion as to which legal standard to argue before the PTAB, with some practitioners arguing either or both standards. See Memorandum at 4. The USPTO recognized that there were fundamental differences between its approach and the district court’s approach. Memorandum at 3. In the past, the Federal Circuit had also declined to decide which standard applies in the post-grant review process. See Tinnus Enters., LLC v. Telebrands Corp., 733 F. App’x 1011, 1018 (Fed. Cir. 2018).