In In re Arunachalam, No. 2016-1607, the Federal Circuit affirmed the PTAB decision holding that Dr. Lakshmi Arunachalam is collaterally estopped from asserting claims in U.S. Patent No. 6,212,556 (’556 Patent) because a district court had invalidated claims in a related patent, U.S. Patent No. 5,987,500 (’500 Patent).

Both patents are directed to systems and methods for engaging in real-time, two-way transactions over a network. In a prior litigation, the Delaware district court invalidated claims in the ’500 Patent. Meanwhile, the ’556 Patent’s patentability was challenged at the PTAB, which found its claims unpatentable. Dr. Arunachalam appealed the PTAB’s decision.

The Federal Circuit held that Dr. Arunachalam is collaterally estopped from arguing the patentability of challenged claims in the ’556 Patent because she had a full and fair opportunity to litigate their validity and patentability. The Court found that the challenged claims are not materially different from those already invalidated by the Delaware district court or found unpatentable by the PTAB. Furthermore, the Court added that Dr. Arunachalam failed to show a reversible error in the PTAB’s decision affirming the Examiner’s rejection over a prior art reference. Therefore, the Federal Circuit dismissed Dr. Arunachalam’s appeal.