The U.S. Patent and Trademark Office issued a significant policy shift on July 31, 2025, announcing it will strictly enforce a procedural rule that has been loosely applied for years, potentially making it harder for challengers to invalidate patents through inter partes review (IPR) proceedings.
Key Policy Change
The USPTO will now strictly enforce 37 C.F.R. § 42.104(b)(4), which requires IPR petitions to “specify where each element of the claim is found in the prior art patents or printed publications relied upon.” This marks a dramatic departure from the agency’s previous practice of waiving this requirement. As Acting USPTO Director Coke Morgan Stewart explained in the memorandum, “enforcement of Rule 104(b)(4) means that applicant admitted prior art (AAPA), expert testimony, common sense, and other evidence that is not ‘prior art consisting of patents or printed publications’ (collectively, ‘general knowledge’) may not be used to supply a missing claim limitation.”
What This Means in Practice
Under the new enforcement approach, IPR petitioners can no longer rely on general knowledge, expert testimony, or common sense to fill gaps in their prior art references when challenging patent claims. Instead, they must point to specific patents or published documents that disclose each element of the challenged claims. However, the USPTO clarified that general knowledge can still play a supporting role. “General knowledge may still be used in an IPR to support a motivation to combine or to demonstrate the knowledge of a person having ordinary skill in the art,” the memorandum states.
Federal Circuit Pressure Forces Change
The policy shift comes in direct response to Federal Circuit decisions that questioned the USPTO’s flexible approach. See Qualcomm Inc. v. Apple Inc., 24 F.4th 1367, 1373-77 (Fed. Cir. 2022) (vacating and remanding to determine whether AAPA improperly formed the “basis” of petitioner’s patentability challenge); Qualcomm Inc. v. Apple Inc., 134 F.4th 1355, 1364-65 (Fed.Cir. 2025) (rejecting USPTO’s “in combination” rule that requires the Board to consider AAPA whenever an IPR petition combines AAPA with prior art patents or printed publications because“it cannot be that AAPA never forms the basis of a ground under § 311 (b) whenever AAPA is combined with prior art patents or printed publications.”).
Stewart acknowledged that “past efforts by the Office to permit limited use of general knowledge to satisfy a missing claim limitation are no longer consistent with Federal Circuit precedent.” The new memorandum supersedes two earlier policy documents from 2020 and 2022 that had explicitly allowed the Patent Trial and Appeal Board to waive the strict requirements of Rule 104(b)(4). Those earlier memoranda had given petitioners more flexibility in how they could challenge patents.
Impact on Patent Challenges
Starting Sept. 1, 2025, this policy change is likely to make IPR proceedings more challenging for petitioners and potentially more favorable to patent owners. Petitioners will need to ensure their prior art references more completely cover all elements of challenged claims, rather than relying on expert testimony or general knowledge to fill evidentiary gaps. The enforcement potentially represents a significant shift in the balance of post-grant patent proceedings, reducing the number of successful patent challenges and strengthening patent rights across various industries.
The authors of www.PatentLawyerBlog.com are patent trial lawyers at Jeffer Mangels Butler & Mitchell LLP. For more information about this case, contact Greg Cordrey at 949.623.7236 or GCordrey@jmbm.com.