IPR Estoppel A Paper Tiger?

After a final written decision issues, an IPR petitioner is statutorily estopped from going back to the district court and arguing that the same claims are “invalid on any ground that the petitioner raised or reasonably could have raised during that inter partes review.” 35 U.S.C. § 315(e)(2). While the application of IPR estoppel is generally straightforward when it comes to prior art patents and publications, the law is murkier when it comes to prior art products.

This question of IPR estoppel and its application to prior art products was recently addressed in Chemours Company FC, LLC v. Daikin Industries Ltd. and Daikin America, Inc., C.A. No. 17-1612 (MN) (D. Del. July 8, 2022), where the District of Delaware denied the plaintiff's motion for summary judgment on IPR estoppel where the defendant asserted physical prior art products as invalidity grounds.