In B&B Hardware v. Hargis Industries, the U.S. Supreme Court held that a decision from the Trademark Trial and Appeal Board (TTAB) can prevent a district court from re-judging issues that have already been decided by the TTAB’s decision, if the “ordinary elements” of issue preclusion are met. This is despite the fact that the details and procedures of litigating before the TTAB are different than those of district court. For issue preclusion to apply, the issue has to be actually litigated before the TTAB, and the TTAB has to decide the issue in a way that is essential to the final judgment of the case.
The same reasoning can be applied to decisions of the Patent Trial and Appeal Board (PTAB), like determinations made during inter partes review. Things like claim constructions made by the PTAB may now preclude district courts from doing their own claim constructions. This may simplify litigation, but give litigants fewer chances to reverse an unfavorable outcome.