USPTO Limits Use of General Knowledge in IPR Proceedings 

On July 31, the United States Patent and Trademark Office issued a memorandum (“Memo”) announcing that the Office will renew enforcement of 37 C.F.R. § 42.104(b)(4) (“Rule 104(b)(4)”) in inter partes review (IPR) proceedings. Rule 104(b)(4) requires a petition for IPR to “specify where each element of the claim is found in the prior art patents or printed publications relied upon.”  

Significantly, the Memo explains that the Office’s renewed enforcement of Rule 104(b)(4) will forbid petitioners from relying on “applicant admitted prior art (AAPA), expert testimony, common sense,” and similar evidence (collectively, “general knowledge”) that does not originate from “prior art patents or printed publications” to address a missing claim limitation. However, the Memo notes that petitioners may still use general knowledge to support a motivation to combine or to demonstrate the knowledge of a person of ordinary skill in the art (POSITA).  

The Office explains that the updated guidance is consistent with recent Federal Circuit precedent concerning whether AAPA can be used to address a missing claim limitation. In Qualcomm, Inc., v. Apple, Inc., 24 F.4th 1367 (Fed. Cir. 2022) (Qualcomm I), the court held that, while the use of AAPA is not categorically excluded, it is not “prior art consisting of patents or printed publications” and cannot form the “basis” of an invalidity ground. The Office subsequently issued guidance allowing the use of AAPA in asserted grounds so long as it was “in combination” with at least one qualifying prior art patent or printed publication. In Qualcomm, Inc. v. Apple, Inc., 134 F.4th 1355 (Fed. Cir. 2025) (Qualcomm II), the court rejected the Office’s guidance regarding the “in combination” use of AAPA and held that AAPA cannot be used even as a partial basis for an invalidity ground. Notably, the Qualcomm II court did not reject reliance on general knowledge in addressing a limitation missing from the cited art where the general knowledge did not form the “basis” for the presented ground.  

Nevertheless, the Office will now “deny an IPR petition” that relies on general knowledge — instead of “prior art consisting of patents or printed publications” — to address challenged claims in a petition. The Memo indicates that renewed enforcement of Rule 104(b)(4) will provide a means for (1) identifying the petitioner’s legal and factual basis for satisfying the threshold for instituting IPR and (2) providing the patent owner with notice as to the basis for the challenge to the claims.  

The updated guidance applies to IPR petitions filed on or after September 1, 2025. 

Takeaways 

Potential petitioners should seek to map elements of a challenged claim to express disclosures in prior art relied upon in their grounds and should carefully scrutinize petitions to ensure that general knowledge is not being leveraged to supply a limitation absent from the prior art. Patent owners should carefully scrutinize petitions for reliance on general knowledge beyond motivation to combine and the knowledge of a POSITA. 

Although the Memo addresses only IPRs, potential petitioners for post-grant review should expect the Office to apply the same reasoning to post-grant review (PGR) under 37 C.F.R. §42.204(b)(4). Rule 204(b)(4), similar to Rule 104(b)(4), requires that a PGR petition challenging patentability “based on prior art” must “specify where each element of the claim is found in the prior art.”