On September 16, 2025, USPTO Acting Director Stewart issued a one-page memorandum directed to the Patent Trial & Appeal Board’s (“Board’s”) consideration of prior findings of fact and conclusions of law where patent claims being challenged in an AIA trial proceeding, or substantially similar patent claims, have already been adjudicated post-issuance before the Office, in district court, or at the ITC.  The memorandum instructs that, in such instances, if the Board “reaches an initial or final decision on a finding of fact or conclusion of law that is different than the prior finding or conclusion of the Office, district court, or the ITC, the Board shall explain in the institution or final written decision why a different outcome is warranted.”  Further, “[a] more detailed explanation is required from the Board when the same or substantially the same evidence and/or arguments that were previously presented to the Office, the district court, or the ITC are being relied upon in the subsequent AIA trial proceeding.”  The Board must “consider relevant materials submitted by the parties from the other proceeding (e.g., an opinion, a judgment, trial testimony, or other evidence) and may authorize additional briefing” in order to make its assessment.