Invalidity Defense Raised Prior To PTAB Challenge Cannot Skirt Estoppel

The Northern District of Iowa recently held that a defendant's motion for partial summary judgment of invalidity was barred after the PTAB issued final written decisions, regardless of when the motion was filed. The defendant filed its motion before the final written decisions were issued, but the court rejected the defendant's argument that the timing of the motion insulated it from estoppel.

The case involved six patents, two of which were the subject of PGR petitions that the defendant filed while the district court litigation was ongoing. During claim construction, the defendant argued that certain claim terms were indefinite. The district court agreed with the defendant and found the terms indefinite as a matter of law. Based on the court's constructions, the defendant filed a motion for partial summary judgment seeking a determination that some of the patents—including the patents subject to PGR—were invalid.