On August 6, 2026, the USPTO’s Appeals Review Panel (“ARP”), led by Director John Squires, issued a precedential decision in Ex parte Baurin, reversing a PTAB decision that had rejected an obviousness-type double patenting (“OTDP”) rejection based on the absence of patent-term-extension concerns. In doing so, the ARP reaffirmed that Federal Circuit precedent continues to recognize a second rationale for Obviousness-type double patenting (“OTDP”): preventing potential harassment caused by multiple assignees asserting patentably indistinct claims. Ex parte Baurin, Appeal No. 2024-002920, Decision on Sua Sponte Rehearing, at 64-70 (ARP Aug. 6, 2026.
Background
The dispute arose from Sanofi’s U.S. Application No. 17/135,529 (“the ‘529 Application”), which traced priority to a 2012 filing and would expire in 2032. The examiner rejected the claims for OTDP over Sanofi’s later-filed U.S. Patent No. 10,882,922 (“the ‘922 Patent”), which was filed in 2017 and expires in 2037. The application and patent were commonly owned and shared several inventors.
Importantly, it was undisputed that the pending claims would have been obvious over the claims of the ‘922 Patent.
The PTAB nevertheless reversed the rejection, reasoning that the ‘529 Application could not improperly extend the term of the later-expiring ‘922 Patent. In the Board’s view, because the challenged application would expire years before the asserted reference patent, OTDP’s core policy concern of unjustified term extension was absent.
The ARP Disagreed – Anti-Harassment Remains a Valid OTDP Rationale
The most consequential aspect of Baurin is the ARP’s reaffirmation of the anti-harassment rationale for OTDP.
Historically, OTDP has served two purposes:
- Preventing unjustified extension of patent exclusivity; and
- Preventing multiple parties from asserting patentably indistinct claims against the same accused infringer.
The PTAB treated the anti-harassment rationale as secondary and insufficient to support an OTDP rejection alone. The ARP, however, found that approach inconsistent with existing Federal Circuit precedent.
In particular, the ARP relied on In re Fallaux and In re Hubbell, both of which recognized potential “harassment by multiple assignees” as a legitimate policy justification for OTDP even where patent-term-extension concerns were weak or nonexistent.
The ARP concluded that it was “compelled” by those precedents to sustain the examiner’s rejection. In its view, the Federal Circuit has repeatedly treated anti-harassment as a genuine component of the OTDP doctrine rather than mere dicta.
As a result, the ARP held that OTDP may apply even where the challenged claims would expire before the asserted reference claims.
An Unusual Twist: The ARP Criticizes the Rule It Applies
Although the ARP ultimately reinstated the OTDP rejection, one of the most notable aspects of the opinion is its skepticism toward the anti-harassment rationale itself.
The panel expressly stated:
“Were the Office not bound by the Federal Circuit’s precedents applying the OTDP anti-harassment rationale, this ARP would clarify that the risk of separate ownership and hypothetical harassment generally should not form a standalone basis for OTDP rejections during examination.”
The ARP characterized the rationale as largely speculative because it often rests on assumptions about future ownership changes and hypothetical litigation that may never occur. The opinion also emphasizes that courts remain capable of addressing genuine instances of abusive conduct if ownership is later divided and multiple suits are filed.
The ARP expressed concern that such rules could discourage collaborative research and disincentivize innovation. These concerns strongly suggest that the ARP views the current state of the doctrine as imperfect and in need of clarification from the Federal Circuit.
The Office’s Framework
Although not binding guidance, the ARP proposed a more administrable OTDP framework focused primarily on the doctrine’s traditional term-extension rationale.
For applications in different patent families, the ARP suggested that examiners focus on patent-term filing dates as a practical proxy for expiration dates. Under that approach, if an asserted OTDP reference has a later patent-term filing date than the application under examination, the inquiry would generally end because no improper extension of exclusivity could occur.
The ARP also suggested several possible limitations on standalone anti-harassment-based rejections, including:
- requiring actual evidence of ownership splitting and resulting harassment;
- requiring a stronger mutual-obviousness showing before applying anti-harassment principles; or
- otherwise limiting the doctrine to avoid unfair consequences for innovators.
The panel repeatedly acknowledged, however, that any substantial change will require further guidance from the Federal Circuit.
Takeaways
Baurin is a significant victory for proponents of a broader OTDP doctrine. For now, the USPTO will continue to recognize anti-harassment as an independent basis supporting OTDP rejections, even where no patent-term-extension concern exists.
At the same time, the opinion reads as an invitation for appellate review. The ARP openly questioned the wisdom of relying on speculative future ownership concerns and highlighted the potential consequences for collaborative innovation and follow-on research.
The next chapter may come soon. The ARP specifically pointed to In re Ablynx N.V., Appeal No. 26-1333, as a case that may provide the Federal Circuit an opportunity to clarify whether anti-harassment remains a standalone basis for OTDP. For now, clients may expect to receive application rejections based on OTDP references that implicate multiple owners or overlapping inventors even if the references expire later.
