Interference Estoppel Appeal Nixed by CAFC Under General Rule of IPR Institution Non-Reviewability
IGT filed its patent application in 2002, while Zynga filed the following year.
By: : Kashish Singh
Update: 2025-07-22 07:00 GMT
Interference Estoppel Appeal Nixed by CAFC Under General Rule of IPR Institution Non-Reviewability
IGT filed its patent application in 2002, while Zynga filed the following year.
A precedential decision by the US Court of Appeals for the Federal Circuit (CAFC) has affirmed the Patent Trial and Appeal Board (PTAB) decision invalidating IGT’s patent claims for secured networks in gaming environments.
IGT had argued that interference estoppel should have prevented Zynga’s inter partes review (IPR) challenge, but the Federal Circuit held that this argument directly attacked the PTAB’s institution decision — which is non-reviewable under 35 U.S.C. §314(d). Citing Cuozzo Speed Technologies v. Lee, the Court found no “shenanigans” or misconduct that could make the institution decision appealable.
IGT filed its patent application in 2002, and Zynga filed a similar one in 2003. The Board of Patent Appeals and Interferences (BPAI), the PTAB’s predecessor, had previously dismissed an interference proceeding because Zynga’s claims lacked written description support, but the PTAB later sided with Zynga’s obviousness challenge.
The CAFC’s decision confirms that estoppel arguments alone do not render an institution decision reviewable.