In an unprecedented PTAB decision involving Spectrum Solutions LLC (“Spectrum”) (Petitioner) and Longhorn Vaccines & Diagnostics (“Longhorn”) (Patent Owner), the Board found all five challenged patents invalid and imposed sanction against patent owner Longhorn for failure to meet the duty of candor and fair dealing. The board determined that Longhorn selectively disclosed testing results to support its claim construction and misled its technical expert with incomplete laboratory data, thereby failed to meet its duty of candor and fair dealing in its actions before the Board. The claims and substitute claims in all five patents asserted by Longhorn were unpatentable due to its sanctionable misconduct. Longhorn was also ordered to provide Spectrum compensatory expenses including attorney fees. On one hand, it is a reminder that duty of candor is a continuing obligation that cannot be ignored even during the IPR proceeding.  On the other hand, it does raise the question whether the PTAB has the authority to invalidate a patent for misconduct.