Skip to main content
May 28, 2024

USPTO Issues Proposed Rule on a New Terminal Disclaimer Requirement


The U.S. Patent and Trademark Office (USPTO) has proposed a new rule that would change the requirements for filing a terminal disclaimer to overcome an obviousness-type double patenting rejection. Under the proposed rule, a terminal disclaimer filed to obviate obviousness-type double patenting would be required to include an agreement by the disclaimant that the patent will be unenforceable if any claim in another patent tied to the first patent through the terminal disclaimer (or chain of terminal disclaimers) is:

  1. Finally held unpatentable or invalid based on anticipation or obviousness by a federal court or the USPTO after exhausting all appeals
  2. Abandoned through the filing of a statutory disclaimer after any anticipation or obviousness challenge has been made against that claim

As a result, successfully invalidating a claim in a reference patent in a prior art challenge would render unenforceable an entire group of patents tied to the reference patent directly or indirectly by terminal disclaimers.

Key potential effects of the proposed rule:

  • Competitors may face a lower bar to gain freedom-to-operate by only needing to invalidate one claim in a reference patent to render a group of tied patents unenforceable, instead of challenging the claims within each patent individually.
  • Patent owners may be less inclined to file terminal disclaimers in their key patents risking unenforceability in view of the proposed rule. They may instead opt to argue against obviousness-type double patenting challenges or amend claims to avoid the need for a terminal disclaimer with the new requirement.
  • Applicants may change filing strategies, such as pursuing more claims of varying scope in a single application instead of filing continuations and filing divisional applications in response to restriction requirements. Applicants may also be more driven to appeal obviousness-type double patent rejections at the Patent Trial and Appeal Board (PTAB), or file reissue applications of reference patents to consolidate rejected claims from pending applications.
  • Overall patent prosecution costs could increase if applicants argue more double patenting rejections or file more claim amendments instead of terminal disclaimers.

The USPTO is accepting public comments on the proposed rule until July 9, 2024. Comments must be submitted through the Federal eRulemaking Portal at using the docket number PTO-P-2024-0003.

We will continue to monitor developments related to this proposed rule and will provide updates regarding any final rule. Please reach out to any of the authors of this Advisory or your regular Arnold & Porter contact if you have any questions or need additional information. If you’d like further details about this development, feel free to read the proposed rules.

* Ritika Vemulapalli contributed to this Advisory. Ritika is a summer associate in Arnold & Porter’s Washington, D.C. office.

© Arnold & Porter Kaye Scholer LLP 2024 All Rights Reserved. This Advisory is intended to be a general summary of the law and does not constitute legal advice. You should consult with counsel to determine applicable legal requirements in a specific fact situation.