ARTICLE
11 August 2026

USPTO Appeals Review Panel Reinstates Double Patenting Rejection in Ex parte Baurin, Limits Reach of Allergan

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The USPTO's Appeals Review Panel has issued a precedential decision in Ex parte Baurin that significantly narrows the circumstances under which the Federal Circuit's Allergan decision can shield applicants from obviousness-type double patenting rejections. The ruling reaffirms that OTDP serves two independent purposes—preventing unjustified patent term extension and preventing harassment from multiple lawsuits—and provides critical guidance for patent prosecutors on when terminal disclaimers and
United States Intellectual Property
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On Aug. 6, the USPTO’s Appeals Review Panel (ARP) issued a precedential decision in Ex parte Baurin, Appeal 2024-002920, reversing a Patent Trial and Appeal Board (PTAB) decision that had overturned an examiner’s obviousness-type double patenting (OTDP) rejection. The decision, authored by USPTO Director John A. Squires, Chief APJ Kalyan K. Deshpande, and Acting Deputy Chief APJ Michelle N. Ankenbrand, reaffirms established OTDP practice and significantly narrows the circumstances in which the Federal Circuit’s Allergan decision can shield applicants from double patenting rejections.

What the ARP Held

The case involved a pending application (No. 17/135,529) and a related issued patent (the ’922 patent), both commonly owned by Sanofi. The examiner had rejected the pending claims as obvious variants of the ’922 patent’s claims. The PTAB reversed, reasoning that because terminal disclaimers already prevented any unjustified extension of patent term, the OTDP rejection was unwarranted. The ARP disagreed. It emphasized that OTDP serves two independent purposes: preventing unjustified timewise extension of patent rights and preventing harassment from multiple lawsuits asserting essentially the same invention. Citing Federal Circuit precedent including FallauxHubbell, and Cellect, the ARP held that the Board erred by treating the absence of term extension as dispositive while disregarding the anti-harassment rationale.

Narrow Reading of Allergan

The ARP distinguished the Federal Circuit’s Allergan decision, which held that a first-filed, first-issued, later-expiring claim cannot be invalidated by a later-filed, later-issued, earlier-expiring reference claim sharing a common priority date. The ARP concluded that Allergan simply does not apply here because the ’529 application was not the first actual filing in its family, has not yet issued, and does not share the same patent term filing date as the ’922 patent. This means the Allergan safe harbor will only rarely, if ever, arise during original examination.

Practical Implications for IP Practitioners

The ARP’s guidance directs USPTO personnel to continue applying existing OTDP practice under MPEP § 804 unless the narrow Allergan fact pattern is met. 

For patent prosecutors, this means applicants should expect examiners to continue making OTDP rejections in the ordinary course and should carefully evaluate family structure, actual and patent term filing dates, issue dates, patent term adjustment, terminal disclaimers, and common ownership when developing prosecution strategy. 

For litigation teams, the decision underscores the importance of terminal disclaimer and common ownership history as factors potentially bearing on validity, enforceability, and case strategy.

Finally, practitioners should monitor the Federal Circuit for further guidance: the ARP expressly acknowledged that higher court clarification would be welcome, and related issues remain pending in In re Ablynx N.V. 

Staying current on these developments will be essential for anyone managing patent portfolios or defending against OTDP-based challenges. In the meantime, consider claim-overlap mapping as an audit point.

Risk-Tiered MATRIX
Risk tier Claim-overlap mapping needed Typical action
Low Same owner, same enforcement control, clear claim differentiation, and no later-expiring problematic asset. A short table identifying independent claims, expiration dates, and distinguishing claim features is generally enough. Preserve a prosecution note explaining why the claims are patentably distinct or why a terminal disclaimer would be available if needed.
Medium Same or affiliated owners, but overlapping commercial embodiments or meaningful PTA/expiration-date differences. Map independent claims and key dependent claims against the same embodiment and note expiration dates. Consider preemptive claim differentiation, dependent-claim pruning, or a terminal-disclaimer strategy if preserving term is less important than allowance.
High Different owners, co-owners, JRA parties, exclusive licensees, or assets that cannot clearly be commonly enforced. Prepare a mini limitation chart for overlapping independent claims and document enforcement-control gaps. Prioritize claim amendment, ownership or enforcement alignment, or a written patentable-distinctness record, because terminal-disclaimer practice may not solve divided-enforcement risk.
Critical Same accused product or method would plausibly infringe claims held or enforceable by different parties, and the claims differ only by routine or obvious variations. Prepare a prosecution-grade claim chart and business/legal mitigation plan. Escalate before allowance, because the anti-harassment rationale may support an OTDP issue even where the term-extension rationale is disputed.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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