United States Patent and Trademark Office banner graphic

USPTO issues memorandum clarifying enforcement of Rule 104(b)(4) in IPR proceedings

United States Patent and Trademark Office sent this bulletin at 07/31/2025 05:23 PM EDT

Having trouble viewing this email? View it as a Web page.

Patent Trial and Appeal Board

**USPTO issues memorandum clarifying enforcement of Rule 104(b)(4) in inter partes review (IPR) proceedings**

Today, the USPTO issued a memorandum explaining that the Office will enforce and no longer waive the requirement of 37 C.F.R. § 42.104(b)(4) that an IPR petition “must specify where each element of the claim is found in the prior art patents or printed publications relied upon.”

To comply with Rule 104(b)(4), an IPR petitioner may not use applicant admitted prior art, expert testimony, common sense, and other evidence (collectively, general knowledge) that is not “prior art consisting of patents or printed publications” to supply a missing claim limitation. An IPR petitioner may still use general knowledge to support a motivation to combine or to demonstrate the knowledge of a person having ordinary skill in the art.

The approach set forth in this memorandum provides a clear means for (i) identifying the petitioner’s legal and factual basis for satisfying the threshold for instituting an IPR and (ii) providing the patent owner with notice as to the basis for the challenge to the claims. The memorandum applies to all petitions for IPR filed on or after September 1, 2025.

Learn more about this memorandum and other resources related to proceedings before the PTAB.

Having trouble accessing links in this email? Your email server security software may be altering the links. Contact your IT or email administrator and ask them to "allow-list" links-1.govdelivery.com and links-2.govdelivery.com to ensure you can access all content in this communication.

Stay connected with the USPTO by subscribing to regular email updates. Visit our subscription center at www.uspto.gov/subscribe to update or change your email preferences.

This email was sent from an unmonitored mailbox. To contact us, please visit our website www.uspto.gov/about/contacts. To ensure that you continue to receive our news and notices, please modify your email filters to allow mail from subscriptioncenter@subscriptions.uspto.gov.