In a recent order, USPTO Director John A. Squires convened the Patent Trial and Appeal Board’s Appeals Review Panel (ARP) and granted sua sponte rehearing in an ex parte appeal involving obviousness-type double patenting (OTDP). The ARP will review the PTAB’s prior reversal of OTDP rejections as to claims 1-18 of Application No. 17/135,529. See Ex parte Baurin Appeal No. 2024-002920 (P.T.A.B. Mar. 2026) (ARP Order). The ARP order sets a single near-term deadline for (i) an appellant OTDP-only brief (≤10 pages) and (ii) amicus briefs (≤10 pages), both due March 27, 2026. See id.

The ARP has identified three topics for focused briefing:

1. How (if at all) Allergan USA, Inc. v. MSN Laboratories applies, including what “first-filed” means for OTDP purposes on facts that differ from Allergan;
2. Whether examiners should determine projected expiration dates to support OTDP rejections during prosecution; and
3. Whether concerns about separate ownership/potential harassment can serve as an independent basis supporting OTDP rejections during prosecution.

PTAB Decision of November 8, 2024

In its Decision on Appeal, the PTAB reversed multiple OTDP rejections of claims 1-18. The ARP rehearing is limited to the Board’s reversal of the OTDP rejections and the issues identified in the ARP Order.

The patents cited in the double patenting rejections were later filed and would expire later than the application on appeal, particularly in view of terminal disclaimers filed in the appealed application. The Decision noted that, “in view of the terminal disclaimers,” any patent issuing from the appealed application could not extend beyond March 28, 2032, while the asserted reference patent terms extended later.

In reversing the rejections, the Board discussed Federal Circuit OTDP decisions (such as Gilead and AbbVie) addressing how “first” and “second” patents can be framed in a post-URAA environment and cited Allergan in describing OTDP’s purpose of preventing a patentee from obtaining a “second patent” to extend exclusivity on patentably indistinct subject matter. The Board acknowledged the facts differed from Allergan (including that Allergan involved patents sharing a common priority date), but nevertheless found aspects of Allergan’s reasoning compelling in the posture presented.

The Board also addressed the examiner’s “separate ownership” point. In the Board’s view, once it concluded the applied reference could not serve as a proper OTDP reference under its reasoning, arguments about the risk of separate ownership were immaterial to the outcome.

The Examiner’s Rehearing Request (and the Board’s Denial)

Following the PTAB’s November 2024 decision, the examiner’s supervisor, Julie Wu (Supervisory Patent Examiner in Art Unit 1643) filed a Request for Rehearing (under MPEP § 1214.04). Request for Rehearing by Examiner Under MPEP § 1214.04, Ex parte Baurin, Appeal No. 2024-002920, at 1 (P.T.A.B.) (requesting rehearing of the Nov. 8, 2024 decision and stating the Board “did not articulate an error with the Examiner’s determination that, under the one-way test, the claims on appeal are not patentably distinct”).

On December 18, 2025, the Board issued a Decision on Request for Rehearing and denied the rehearing request. Decision on Request for Rehearing, Ex parte Baurin, Appeal No. 2024-002920, at 2 (P.T.A.B. Dec. 18, 2025) (“We DENY the Examiner’s requested relief.”). The rehearing decision was issued by a panel of three administrative patent judges (APJs), and included a dissent by one of the APJs, expressing agreement with all but one of the Examiner’s reasons.  The dissenting APJ had replaced one of the three APJs that had rendered the November 2024 decision.

In denying rehearing, the Board addressed issues that track the ARP’s three questions, including how Allergan should be applied in this posture (if there can be no extension of patent term, then a patent is not a proper OTDP reference), how term and expiration relate to OTDP during prosecution (must follow Federal Circuit precedent and identify a proper OTDP reference by comparing effective filing dates and expiration dates), and the role of separate ownership concerns (not an independent basis for making an OTDP rejection).

Relevant Federal Circuit Case Law

Because the ARP’s order expressly requests briefing on Allergan, it is likely to be a central reference point in the ARP’s analysis. In Allergan, the Federal Circuit addressed OTDP in a common-priority fact pattern and held that a first-filed, first-issued, later-expiring claim cannot be invalidated by later-filed, later-issued, earlier-expiring reference claims sharing the same priority date. Allergan USA, Inc. v. MSN Labs. Priv. Ltd., 111 F.4th 1358 (Fed. Cir. 2024).

Allergan’s discussion of filing sequence and expiration dates provides context for the ARP’s first question, what “first filed” means on different facts, and its second question, whether and how projected expiration dates should be considered during prosecution. The Federal Circuit explained that, after the Uruguay Round Agreements Act (URAA), “a patent’s term is now measured from its effective filing, or priority, date,” and that patents sharing a priority date “are expected to expire on the same day.” Id. at 1367-68 (citing 35 U.S.C. § 154(a)(2)). The court then noted that a common priority date “does not always guarantee a common expiration date,” because PTA can cause two commonly owned patents that otherwise would expire on the same day to have different expiration dates. Id. at 1368 (citing 35 U.S.C. § 154(b); AbbVie Inc. v. Mathilda & Terence Kennedy Inst. of Rheumatology Tr., 764 F.3d 1366, 1373 (Fed. Cir. 2014)). The opinion further explains that, where patentably indistinct inventions have different expiration dates due to PTA, any OTDP concern is “commonly obviated” during prosecution by filing a terminal disclaimer that ties the later-filed application’s expiration and ownership to the earlier-filed application. Id. (citing Boehringer Ingelheim Int’l GmbH v. Barr Labs., Inc., 592 F.3d 1340, 1346 (Fed. Cir. 2010)); see also id. (citing 35 U.S.C. § 154(b)(2)(B)).

For the ARP’s second question, whether examiners should determine projected expiration dates in prosecution, another Federal Circuit decision frequently cited in the OTDP/PTA landscape is In re Cellect. In re Cellect, LLC, 81 F.4th 1216 (Fed. Cir. 2023).

Cellect held that, for OTDP purposes, the relevant expiration date for a PTA-adjusted patent is the expiration date after PTA is added. In re Cellect, LLC, 81 F.4th 1216, 1226-27 (Fed. Cir. 2023) (holding “the expiration date used for an ODP analysis where a patent has received PTA is the expiration date after the PTA has been added”). The court explained that an OTDP determination requires identifying the “later-expiring patent,” which is why “the date when PTA or PTE is applied matters,” and it held that PTA and PTE should be treated differently in OTDP analyses. Id. at 1226. The opinion also describes OTDP’s equitable rationales to include preventing “an improper timewise extension of a patent term” and preventing “split ownership of related patents and subsequent potential harassment by multiple owners or assignees.” Id. at 1221. These points relate directly to the ARP’s third question, which asks whether separate ownership and anti-harassment concerns can independently support an OTDP rejection during prosecution. In addressing those concerns, the court agreed with the Board that a “risk of separate ownership existed” and that a terminal disclaimer would have been required to ensure common ownership, notwithstanding Cellect’s representation that it would not transfer the patents. Id. at 1230. Finally, the court rejected the notion that OTDP can be cured after expiration, stating that “invalidating only the [PTA] adjustment would be tantamount to granting a retroactive terminal disclaimer” and that “[a] terminal disclaimer is not an escape hatch to be deployed after a patent expires.” Id. at 1231.

Requisite Level of Analysis for OTDP Rejections

A related issue in OTDP rejections is how much analysis must appear in the record to support an OTDP rejection, especially where claim differences exist and patentable distinctness is contested.

MPEP 804(II)(B) requires that “the examiner should first construe the claim(s) in the application under examination and the claim(s) in the reference application or patent to determine what are the differences. Then the examiner should determine whether those differences render the claims patentably distinct using an anticipation analysis and/or an obviousness analysis.”  (citing Pfizer, Inc. v. Teva Pharms. USA, Inc., 518 F.3d 1353, 1363, 86 USPQ2d 1001, 1008 (Fed. Cir. 2008)). 

The MPEP states that the following factual inquiries must be performed by the Examiner:

(A) Determine the scope and content of a patent claim relative to a claim in the application at issue;

(B) Determine the differences between the scope and content of the patent claim as determined in (A) and the claim in the application at issue;

(C) Determine the level of ordinary skill in the pertinent art; and

(D) Evaluate any objective indicia of nonobviousness.

Any nonstatutory double patenting rejection made under the obviousness analysis should make clear:

(A) The differences between the inventions defined by the conflicting claims — a claim in the patent compared to a claim in the application; and

(B) The reasons why a person of ordinary skill in the art would conclude that the invention defined in the claim at issue would have been an obvious variation of the invention defined in a claim in the patent.

MPEP § 804(II)(B)(2). 

In Ex parte Mobile Tech, Inc., the Board addressed the sufficiency of an OTDP “record,” explaining that the examiner’s OTDP rejection (in that reexamination) “consists solely of tables” and that “there is no accompanying explanation or analysis.” Ex parte Mobile Tech, Inc., Appeal No. 2022-001034, at 6 (P.T.A.B. Feb. 11, 2022). The Board emphasized that this was “problematic particularly where . . . there are differences between the claims, differences that demand an explanation why they are not patentably distinct to render the claims obvious variations of each other.” Id.

What to Watch Next

We are closely monitoring developments in regard to this Order and will continue to provide updates.  Given the framing of the three questions, the intent appears to be for the ARP to find that the Baurin decision is distinguishable from Allergan, that it would be unworkable for examiners to project expiration dates, and that the separate ownership prong has never been held to be not support a OTDP rejection on its own.  Applicants would still get Allergan-style protection inside a single patent family, but other commonly owned later-filed, later-expiring references would remain viable OTDP references.

Disclaimer: The information contained in this posting does not, and is not intended to, constitute legal advice or express any opinion to be relied upon legally or otherwise. If you would like to obtain legal advice relating to the subject matter addressed in this posting, please consult with us or your attorney. The information in this post is also based upon publicly available information, presents opinions, and does not represent in any way whatsoever the opinions or official positions of the entities or individuals referenced herein.