Deliberate Choices Made During Patent Prosecution are Not "Errors" Correctable by Reissue

June 10, 2014

Daniel T. Wehner PhD

What This Means to You

  • Exercise caution when filing papers during patent prosecution that could impact subsequent patent enforceability.
  • Confirm that a patent or patent application is commonly owned or subject to a joint research agreement before filing a terminal disclaimer.
  • When performing diligence or during litigation, investigate the co-ownership history of patents subject to terminal disclaimers to assess the enforceability of those patents.


In In Re Dinsmore, the U.S. Court of Appeals for the Federal Circuit (Federal Circuit) confirmed that errors fixable with reissue do not include intentional choices made during prosecution. The Federal Circuit held that the common ownership requirement of a valid terminal disclaimer filed to overcome a double patenting rejection cannot be altered via reissue.

Case Background

During prosecution of the patent application leading to U.S. Patent 7,236,568 (‘568 patent), the applicants filed a terminal disclaimer to overcome a non-statutory obviousness-type double patent rejection over U.S. Patent 6,658,086 (‘086 patent). A terminal disclaimer shortens the term of a patent granted on a pending application to the term of an earlier-filed patent, and includes a requirement that the shortened-term patent is enforceable only during a period in which both patents are commonly owned. The ‘086 patent and the ‘568 patent were never commonly owned, thereby rendering the ‘568 patent unenforceable upon issue. A subsequent request to reissue the ‘568 patent was denied by the U.S. Patent and Trademark Office, and several other attempts to address the commonly-owned language in the terminal disclaimer were ineffective.

Decision Analysis

The patentees argued that because the ‘568 and ‘086 patents were never commonly owned, the terminal disclaimer was invalid and ineffective, and its filing was an “error” correctable by reissue. The Federal Circuit disagreed, stating that the terminal disclaimer on its face contained no errors, and the patentee did not allege or show that it had a mistaken belief about the plain language of the disclaimer or that the patents were commonly owned. Rather, the Federal Circuit stated “an intentional choice was made to surrender a possible right (the ability to obtain all or some of the ‘568 patent claims in a form enforceable independently of the ‘086 patent) in exchange for a benefit (overcoming an obviousness-type double patenting rejection of several of the proposed claims),” and indicated that the fact that the patentee now seeks to revise this choice is not an error correctable by reissue.


Reissue applications are not a cure-all for correcting intentional choices made during prosecution. In particular, terminal disclaimers are difficult to rescind or modify after a patent issues. Accordingly, patent practitioners should exercise care by investigating current and expected future common ownership prior to filing terminal disclaimers to overcome double patenting rejections. Alternate strategies for overcoming obviousness-type double patenting rejections during prosecution, such as amending the claims, should also be considered to avoid potential future enforcement difficulties with patents subject to a terminal disclaimer.