IP News
USPTO Restores Anti-Harassment Basis for Double Patenting Rejections in Precedential Baurin Decision
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On August 6, 2026, a USPTO Appeals Review Panel (ARP) issued a precedential decision in Ex parte Baurin, reversing a prior Patent Trial and Appeal Board (PTAB) panel and restoring an examiner's obviousness-type double patenting (OTDP) rejection. The panel held that under controlling Federal Circuit precedent, OTDP rejections during pre-grant prosecution can stand on the anti-harassment rationale alone, even when the pending claims present no risk of improperly extending a patent's term. The ruling narrows the practical reach of the Federal Circuit's Allergan v. MSN decision and maintains strict compliance requirements for US continuation filings.
In Ex parte Baurin (Appeal 2024-002920), an ARP comprising USPTO Director John A. Squires, PTAB Chief Judge Kalyan Deshpande, and Acting Deputy Chief Judge Michelle Ankenbrand issued a precedential ruling on sua sponte rehearing. The decision reversed a November 8, 2024 PTAB ruling that had set aside an examiner's OTDP rejection against U.S. Application No. 17/135,529, directed to antibody-like binding proteins. The examiner had rejected the '529 application claims over U.S. Patent No. 10,882,922, which was filed later and expires later than any patent that would issue from the '529 application. The ARP held that the narrow OTDP exception established in Allergan USA, Inc. v. MSN Laboratories Private Ltd. (Fed. Cir. 2024) did not apply because the '529 application was not the first actual filing in its family, was still pending rather than first-issued, and lacked a common priority date with the reference patent. Furthermore, relying on earlier Federal Circuit authority such as Fallaux, Hubbell, and Cellect, the ARP concluded that the risk of separate ownership and potential harassment by separate owners of obvious variants independently supports OTDP rejections during prosecution, regardless of term-extension concerns.
The PTAB's original November 2024 decision and its December 18, 2025 denial of rehearing reasoned that OTDP exists primarily to prevent an unjustified timewise extension of patent exclusivity. Because the '529 application would expire before the cited '922 reference patent, the original Board panel concluded that OTDP could not apply and dismissed the examiner's separate-ownership concerns as immaterial. However, the ARP clarified that Federal Circuit law recognizes two distinct justifications for OTDP: preventing improper term extension and preventing harassment from multiple patent owners asserting obvious variations of the same invention. While the ARP questioned whether a standalone anti-harassment rationale might harm innovation, it concluded that existing appellate precedent binds the USPTO to enforce both rationales.
This ruling reinforces that US patent applicants cannot rely on Allergan to defeat OTDP rejections simply because the target application will expire earlier than the cited reference patent. During pre-grant prosecution, examiners retain full authority to issue OTDP rejections based on disclosure made in later-filed applications across a portfolio. For Korean and Asian companies filing in the United States, this holding imposes significant structural risks in joint ventures and collaborative R&D. If an earlier-filed US application receives an OTDP rejection based on a co-developed or jointly assigned later-filed patent, the applicant must either execute a terminal disclaimer or narrow the pending claims. Because a terminal disclaimer requires common ownership, failure to maintain unified ownership across related US cases will create an insurmountable OTDP bar. In contrast to US practice, where double patenting rules are judicially created and addressed via disclaimers, KIPO enforces statutory double patenting under Article 36 of the Korean Patent Act, while strict amendment limits under Article 47(2) restrict post-filing corrections. To safeguard portfolios, corporate IP teams should audit cross-licensed and co-developed application families to ensure assignment provisions mandate unified record title across all US continuation and divisional filings.
The ARP explicitly invited the Federal Circuit to clarify whether the anti-harassment rationale should remain an independent ground for OTDP rejections when no term extension exists. Until the appellate court revisits the doctrine, applicants must anticipate OTDP rejections against pending continuation applications generated by later-filed family members. While the federal appeal remains pending, prosecution attorneys should proactively review portfolio filing chains, maintain common ownership records across all related filings, and prepare to file terminal disclaimers early in prosecution whenever ownership is held by a single entity.