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USPTO's Proposed New Terminal Disclaimer Rule Would Change Applicant and Patent Challenger Strategy

The United States Patent and Trademark Office (USPTO) has proposed changes to terminal disclaimer rules that could significantly complicate patent prosecution strategy for patent applicants and simplify attacking multi-patent families for patent challengers.

Under the proposed rule, if a terminal disclaimer is filed to overcome a nonstatutory double patenting rejection in an application, a patent issuing from that application would become unenforceable if it is "tied" by that terminal disclaimer to another patent that has any claim declared invalid. 


Applicant receives Patent A and files a continuation application (Application B) with claims that are similar (but not identical) to those issued in Patent A. During prosecution of Application B, the patent office issues a nonstatutory double-patenting rejection in view of the issued claims of Patent A. Under current practice, Applicant could simply file a terminal disclaimer to obviate this rejection, which would make a patent that issues from Application B (Patent B) expire no later than the expiration date of Patent A. But under the proposed rule, upon filing such a terminal disclaimer, Applicant would additionally need to agree that Patent B would become unenforceable if any claim of Patent A is later rendered invalid for anticipation or obviousness. Importantly, the unenforceability would not work in reverse. In other words, if Patent B is later found invalid, there would be no effect on the enforceability of Patent A.

Changes in Strategy

The proposed rule could significantly affect applicants' patent prosecution strategies, particularly related to multi-patent families. Currently, applicants routinely file terminal disclaimers to overcome nonstatutory double patenting rejections in continuation applications. Such rejections are often the only hurdle standing in the way of an application being allowed, and the “penalty" of expiration along with a parent patent does not deter most applicants. But if the USPTO implements the proposed rule, an entire patent family could become unenforceable if any single claim of a parent patent is deemed invalid. Accordingly, applicants could be incentivized to argue against double-patenting rejections or to draft claims that are more distinctive over those of the parent patent.

On the flip side, challenging the validity of multi-patent families under the proposed rule would be simplified in many instances. For example, it is not uncommon for patent owners to pursue accused infringers based on several patents in a single family. Often, one or more of those patents are tied to other patents in the family through terminal disclaimers that were filed during prosecution to overcome double-patenting rejections. Instead of attacking every patent in the family (e.g., through reexamination or inter partes review), the patent challenger could simply attack the parent patent to which the other patent-family members may be tied. If successful, the patent challenger could render an entire family unenforceable at a fraction of the cost of challenging every patent in the family.  

Notably, the proposed rule's mechanism of unenforceability is through an agreement submitted along with the terminal disclaimer by the applicant during prosecution. Accordingly, there should be no effect on current patent families, but only future patents in which such an agreement has been filed. Additionally, the unenforceability would only be triggered by invalidity based on prior art (i.e., under §§ 102 or 103), and not invalidity due to unpatentable subject matter (i.e., under § 101).  

The USPTO will keep comments open at the link below until July 9, 2024.


patents, intellectual property, uspto