USPTO convenes an Appeals Review Panel and authorizes amicus briefing to consider the basis for rejecting a patent application under the doctrine of obviousness-type double patenting.
Executive Summary
The Director of the U.S. Patent and Trademark Office (USPTO) has convened an Appeals Review Panel (ARP) and authorized amicus brief submissions through March 27, 2026, to address what bases may support rejecting a patent application under the doctrine of obviousness-type double patenting (OTDP). The Director is requesting amici address the issues in dispute in the recent decision by the Patent Trial and Appeal Board (Board) in Ex Parte Baurin. In Ex Parte Baurin, the Board reversed a patent examiner’s OTDP rejection of a patent application based on reference patents and patent applications having later priority and expiration dates.
Obviousness-Type Double Patenting
Obviousness-type double patenting (OTDP) is a judicially created doctrine dating back to the 19th century that prevents two patents from being granted on patentably indistinct inventions. Under this doctrine, an inventor is prevented from unjustly extending their patent rights by obtaining a second patent that is patentably indistinct from a first patent.
An OTDP analysis requires considering the difference between the claim(s) of the patent or patent application at issue, and the claim(s) of a reference patent or patent application. If the difference would have been obvious over the reference claim(s), then the claim(s) of the patent or patent application at issue are patentably indistinct, and invalid or unpatentable under the OTDP doctrine.1
In specific circumstances, an OTDP rejection can be overcome by filing a terminal disclaimer (TD) in the patent or patent application at issue. A TD acts as a legal remedy to an OTDP rejection by requiring that the patent applicant or owner agrees that the patent or patent application at issue will not expire later than the reference patent or patent application. As such, patent rights are not being unjustly extended. A TD also requires that the patent or patent application at issue remain under common ownership with the reference patent or patent application.2
Ex Parte Baurin
The issue under appeal in Ex Parte Baurin is whether patents and patent applications that have a later priority date, and are later-expiring, are appropriate references that could support an OTDP rejection.3 In its decision that such patents and patent applications are not appropriate references, the Board applied the reasoning from Allergan USA, Inc. v. MSN Labs. (Fed. Cir. 2024) (Allergan), which states that the purpose of the OTDP doctrine ‘“is to prevent patentees from obtaining a second patent on a patentably indistinct invention to effectively extend the life of a first patent to that subject matter’” (emphasis added).4
After the Board decision, the patent examiner whose OTDP rejection was reversed, requested a rehearing based on the grounds that the Board “misapprehended” the holding in Allergan, the Board’s decision was inconsistent with USPTO guidance, and the risk of separate ownership between the patent application at issue and the reference patents and patent applications is material to a finding of OTDP.5 In the Board’s decision to deny the request for rehearing, the Board acknowledged that there were factual differences between Allergan and the present case, but affirmed its reasoning based on the principles in Allergan.6
USPTO Order
On March 5, 2026, the Director of the USPTO announced that it convened an ARP to examine the issues raised in Ex Parte Baurin.
The ARP consists of the Director of the USPTO, the Acting Commissioner for Patents, and the Chief Administrative Patent Judge. The order invites Appellant and amicus curiae submissions by March 27, 2026, to address the following:
- the applicability, if any, of [Allergan] to the facts of this appeal, and consideration of what constitutes ‘first-filed’ for OTDP purposes under facts different than those presented in Allergan;
- whether examiners should determine projected expiration dates to support OTDP rejections during prosecution; and
- whether the risk of separate ownership and preventing potential harassment by separate owners of claims to obvious variants of an invention is an independent basis that supports an OTDP rejection during prosecution. 7
Conclusion
The USPTO’s authorization to submit amicus curiae addressing the issues in Ex Parte Baurin provides interested parties, including private companies, a unique opportunity to comment on the grounds for which an examiner can reject a claim under the doctrine of obviousness-type double patenting.8 Comments can be submitted to PTABAppealsAdmin@uspto.gov until March 27, 2026.
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[1] Federal Circuit Provides Guidance on What Claims Can Properly Serve As Obviousness-Type Double Patenting References. For further information regarding obviousness-type double patenting, please see Wilson Sonsini’s publication: https://www.wsgr.com/en/insights/federal-circuit-provides-guidance-on-what-claims-can-properly-serve-as-obviousness-type-double-patenting-references.html.
[3] Ex Parte Baurin, Appeal 2024-002920, Appl. No. 17/135,529 (PTAB Dec. 18, 2025).
[4] Allergan USA, Inc. v. MSN Labs. Private Ltd., 111 F.4th 1358 (Fed. Cir. 2024); see also id and Wilson Sonsini’s publication: https://www.wsgr.com/en/insights/federal-circuit-provides-guidance-on-what-claims-can-properly-serve-as-obviousness-type-double-patenting-references.html.
[5] Ex Parte Baurin, Appeal 2024-002920, Appl. No. 17/135,529 (PTAB Dec. 18, 2025).
[7] Ex Parte Baurin, Appeal 2024-002920, Appl. No. 17/135,529 (PTAB Mar. 5, 2026) (USPTO convenes Appeals Review Panel to reconsider rejection of claims).
[8] The Director’s previous sua sponte review of a Board decision in Ex Parte Desjardins, resulted in a new memorandum from the USPTO providing guidance on the subject matter eligible for patent protection.
