WASHINGTON — The Patent Trial and Appeal Board's penchant for picking and choosing the grounds for inter partes review has taken center stage this week at the U.S. Court of Appeals for the Federal Circuit.

On Tuesday, two judges defended the PTAB's practice as a reasonable interpretation of the board's statutory rule-making authority, but a third judge said it's causing serious problems.

“What looked on its face like an extraordinarily salutary development in reviving and revitalizing this patent system,” Judge Pauline Newman said, “is instead being interpreted in a way that it's worse than it was before.”