Developing Story
Ex Parte Baurin – PTAB Obviousness-Type Double Patenting Rehearing (2026)
Ex Parte Baurin is a PTAB rehearing case on obviousness-type double patenting under review by a USPTO Appeals Review Panel, with prominent academic amici including Mark Lemley arguing against the Board's analysis. The outcome could set significant internal USPTO precedent affecting patent prosecution strategy across pharma and biotech. It is part of a broader flux in PTAB doctrine with structural implications for patent portfolio management.
Importance: 72%Confidence: 85%Mentions: 1Updated: April 13, 2026
## Overview
Ex Parte Baurin is a 2025 Patent Trial and Appeal Board (PTAB) rehearing decision on obviousness-type double patenting (ODP) that is now under review by a USPTO Appeals Review Panel (ARP) (IPWatchdog, April 9, 2026). The case has attracted significant amicus attention, including a notable brief from Professors Mark Lemley and Lisa Larrimore Oullette arguing that Federal Circuit precedent supports the patent examiner's rejections and that the Allergan holding is inapplicable (IPWatchdog, April 9, 2026).
## Key Facts
- Amicus briefs have been filed and posted to the USPTO site in Ex Parte Baurin (IPWatchdog, April 9, 2026)
- Most amici reportedly support the PTAB Board's analysis (IPWatchdog, April 9, 2026)
- Professors Mark Lemley and Lisa Larrimore Oullette submitted a brief contending Federal Circuit precedent supports the examiner's ODP rejections and that Allergan's holding does not apply (IPWatchdog, April 9, 2026)
- The case is being reviewed by a USPTO Appeals Review Panel (ARP), an elevated internal review mechanism
## Legal Significance
- ODP doctrine prevents applicants from obtaining multiple patents with overlapping claim scope and different expiration dates — a critical tool for limiting patent term extension strategies
- The Allergan decision (referenced by amici) addressed ODP in the context of patent families — its scope is actively contested
- A ruling by the ARP could set significant internal USPTO precedent affecting pharmaceutical, biotech, and technology patent prosecution
- This case connects to the broader trend of The Enforcement Asymmetry narrative: patent holders have been gaining structural advantages; an ARP ruling clarifying ODP could cut both ways
## Connections
- Relates to the existing IPR Institution Rate Decline narrative — PTAB doctrine is in active flux across multiple fronts
- Lemley's involvement signals academic and policy community concern about patent term extension strategies in pharma
## Watch
- ARP ruling and its precedential weight within USPTO
- Whether the Federal Circuit subsequently addresses ODP doctrine in a related case
- Pharma and biotech patent prosecution strategy adjustments in response