On August 6, 2026, an Appeals Review Panel reversed an earlier Patent Trial and Appeal Board decision and reinstated obviousness-type double-patenting rejections involving claims 1 through 18 of Sanofi’s application No. 17/135,529. The ruling, Ex parte Baurin, Appeal 2024-002920, is now precedential within the USPTO.

The decision did not create a new statute or final statutory rule. Instead, it applied the judge-made, nonstatutory doctrine of obviousness-type double patenting, or OTDP, under Federal Circuit precedent the panel said remains binding.

What the panel decided

The earlier PTAB decision had reversed the examiner’s OTDP rejections. The Appeals Review Panel, convened by USPTO Director John A. Squires, reversed that outcome and affirmed the examiner’s rejections.

The central question was whether the possibility of separate ownership and multiple enforcement actions can independently support an OTDP rejection when issuing the later patent would not obviously extend the term of an earlier patent.

The panel said it can under current Federal Circuit law. It concluded that the Federal Circuit has recognized an “anti-harassment” rationale as a policy foundation of OTDP. In practical terms, the concern is that related claims could be held by different owners, forcing a licensee or accused infringer to negotiate with, or defend against, more than one rights holder over patentably indistinct subject matter.

The panel described a hypothetical licensee that believes it has broad rights under one patent but later faces a separate negotiation or infringement suit from the owner of a related patent. It said preventing that possibility remains a legitimate basis for the rejection in the circumstances before it.

Why the Allergan exception did not control

The panel also addressed the Federal Circuit’s 2024 decision in Allergan USA, Inc. v. MSN Laboratories Private Ltd. That decision limited an OTDP challenge involving a first-filed, first-issued patent that expired later than a later-filed, earlier-expiring reference patent with a common priority date.

The Appeals Review Panel said that exception did not apply to Sanofi’s application. The application was not the first actual filing in the relevant family, and the application and reference patent had different patent-term filing dates.

Those concepts are related but not identical. An actual filing date records when a particular application was submitted. A patent-term filing date is the effective filing date used to calculate the standard patent term, generally tied to the earliest qualifying U.S. application in the chain. The panel said the distinction mattered to its treatment of Allergan.

What it means for patent applicants

For now, applicants should expect USPTO personnel to continue applying pre-Allergan OTDP practice unless the Federal Circuit provides further guidance or the law changes. The agency’s instruction does not mean every continuation or related application will be rejected. It describes how the Office will approach OTDP under the legal principles and facts relevant to the case.

A terminal disclaimer may overcome some OTDP rejections by preventing a later patent from extending beyond the related patent’s term. But a terminal disclaimer generally includes common-ownership requirements and can limit enforceability if the patents are no longer commonly owned.

That can create complications when related rights are divided among companies, transferred in separate transactions or licensed under arrangements that do not preserve common ownership. A terminal disclaimer is therefore one possible response to an OTDP rejection, not an automatic solution for every applicant.

The practical effect is to make continuation planning, family filing dates, ownership structure and licensing arrangements more important for companies with related patent portfolios. The ruling is not legal advice and does not establish that a particular application will receive an OTDP rejection.

What remains unsettled

The panel upheld the rejection but questioned whether a freestanding anti-harassment rationale could harm innovation by allowing a later-filed, later-expiring patent to be rejected even when there is no clear term-extension concern.

It proposed a possible future framework aimed at making examination more predictable if the Federal Circuit later rules that anti-harassment alone cannot support an OTDP rejection. The proposal is not a final USPTO rule, and the panel did not present it as a current replacement for existing practice.

The next major development to watch is whether the Federal Circuit defines the limits of the anti-harassment rationale and clarifies when the Allergan exception applies. Until then, the USPTO’s current position is that personnel should continue applying pre-Allergan practice.

Sources

• USPTO Appeals Review Panel decision in Ex parte Baurin
• IPWatchdog analysis of the Baurin ruling