Companies that have been closely watching the use of inter partes review to challenge patents received an important signal on June 20 when the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB) invalidated a score of pharmaceutical claims.

Joseph Cwik, a litigation partner at Husch Blackwell, said it is believed to be the first time the PTAB has issued a final written decision on an inter partes review (IPR) in a pharma case.