Ian Sannes is a patent attorney with Suiter Swantz IP. Ian graduated with honors from North Dakota State University, receiving his B.S. in Mechanical Engineering, and received his Juris Doctor from the University of Minnesota Law School. Ian is registered to practice before the United States Patent and Trademark Office.
Patent challengers and owners alike should take note of a significant shift in Inter Partes Review (IPR) practices at the USPTO.
Effective September 1, 2025, the agency will strictly enforce a rule mandating that IPR petitions explicitly identify where each element of a challenged claim appears in the relied-upon prior art patents or printed publications—without relying on general knowledge, common sense, or similar evidence to bridge any gaps. This change, outlined in a July 31, 2025 memorandum from Acting Director Coke Morgan Stewart, is poised to make it more difficult for petitioners to institute reviews, thereby tilting the balance toward patent owners and potentially reducing the number of successful IPR challenges.
This adjustment could substantially impact litigation strategies, as petitioners who previously leaned on broad interpretations or expert insights to fill evidentiary voids may now face denials of institution. For patent owners, it enhances defenses against invalidity attacks, preserving the value of their intellectual property portfolios. Understanding these nuances is essential for navigating post-grant proceedings effectively.
Overview of the Change
The core of the new guidance stems from 37 C.F.R. § 42.104(b)(4), which requires that an IPR petition “must specify where each element of the claim is found in the prior art patents or printed publications relied upon.” See 37 C.F.R. § 42.104(b)(4). Previously, the USPTO had issued memoranda in August 2020 and June 2022 providing guidance that allowed petitioners flexibility to incorporate general knowledge—such as applicant admitted prior art (AAPA), expert testimony, or common sense—to address missing claim limitations in certain circumstances.
That guidance is now superseded. The July 31, 2025 memorandum revokes the prior approach and mandates full compliance, meaning petitions failing to map every claim element directly to qualifying prior art (patents or printed publications) shall be denied under 35 U.S.C. § 312(a)(4) for failing to comply with Rule 42.104(b)(4).
This aligns with the statutory scope of IPRs, which limits challenges to grounds based “only on the basis of prior art consisting of patents or printed publications.” See 35 U.S.C. § 311(b).
Key Restrictions on General Knowledge and AAPA
Under the enforced rule, “general knowledge”—a broad category encompassing AAPA, expert declarations, common sense, and other non-patent or non-printed publication evidence—cannot be used to supply a missing claim limitation. For example, if a prior art reference lacks a specific element, petitioners can no longer argue that a person of ordinary skill in the art (POSITA) would inherently understand or fill that gap based on background knowledge.
This extends explicitly to AAPA, which refers to admissions in the patent specification or prosecution history. While AAPA was previously combinable with prior art under the now-rejected “in combination” approach, the memorandum clarifies it qualifies as general knowledge and thus cannot bridge evidentiary gaps. This stance responds to Federal Circuit precedents, including Qualcomm Inc. v. Apple Inc., 24 F.4th 1367 (Fed. Cir. 2022) and Qualcomm Inc. v. Apple Inc., 134 F.4th 1355 (Fed. Cir. 2025), which rejected the use of AAPA as a basis for challenges when it supplies missing elements.
However, not all uses of general knowledge are prohibited. It remains permissible for supporting a motivation to combine references or demonstrating how a POSITA would interpret or apply a prior art disclosure. See, e.g., Unification Techs. LLC v. Micron Tech. Inc., 2024 WL 3738401 (Fed. Cir. Aug. 9, 2024) (allowing expert testimony and AAPA to explain POSITA understanding without supplying missing limitations).
Petitioners must carefully distinguish these roles to avoid denial.
To Whom Does This Guidance Apply?
The memorandum applies universally to all IPR petitions filed on or after September 1, 2025, regardless of the technology area or parties involved.
It does not retroactively affect ongoing proceedings or petitions filed before this date. For petitioners, this raises the bar for institution, requiring meticulous claim charting and potentially more robust prior art searches. Patent owners, conversely, gain leverage: incomplete petitions can be challenged at the outset, potentially deterring frivolous or weakly supported attacks. Notably, the guidance may create tension with recent case law. For instance, in Shockwave Medical, Inc. v. Cardiovascular Systems, Inc., No. 2023-1864 (Fed. Cir. July 14, 2025), the Federal Circuit held that AAPA could supply missing limitations without violating 35 U.S.C. § 311(b), suggesting the USPTO’s rule enforcement might be narrower than statutory allowances.
Future litigation could clarify this interplay.
Rationale and Effective Date
The USPTO’s rationale emphasizes clarity, efficiency, and fairness in the patent system. Enforcing the rule ensures petitioners provide a complete legal and factual basis upfront, giving patent owners proper notice and streamlining Board decisions. It also aligns with economic considerations under 35 U.S.C. § 316(b), promoting the integrity of patents by curbing over-reliance on non-qualifying evidence.
As noted, the changes take effect for petitions filed on or after September 1, 2025. Practitioners should review and adjust strategies immediately, as the window for filing under the old regime closes soon.
Other Considerations
Navigating these updates requires precision in petition drafting. Petitioners are advised to conduct thorough prior art analyses and include detailed mappings for every claim element, avoiding any dependence on general knowledge for core limitations.
Patent owners might proactively strengthen specifications to minimize AAPA vulnerabilities. Internationally, while IPRs are U.S.-specific, similar post-grant opposition systems in Europe (e.g., at the EPO) or Japan often require explicit evidence mappings without heavy reliance on general knowledge, so global strategies should account for these parallels. In the U.S., failure to comply could lead to denied institutions, underscoring the need for diligent preparation in an increasingly patent-owner-friendly landscape.
Suiter Swantz IP is a full-service intellectual property law firm providing client-centric patent, trademark, and copyright services. If you need assistance with an intellectual property matter and would like to speak with one of our attorneys, please contact us at info@suiter.com.