UPDATED Sept. 18, 2019, with additional inter partes win for KFx.

KFx Medical yesterday defeated a challenge by Stryker (NYSE:SYK) to one of its patents covering orthopedic suture anchors when the U.S. Patent Trial & Appeals board declined to initiate an inter partes review.

U.S. patent no. 7,585,311, covering a “System and method for attaching soft tissue to bone,” was already the subject of lengthy battle between Carlsbad, Calif.-based KFx and Arthrex. After suing Arthrex in August 2011, KFx won more than $30 million in damages. A higher court denied Arthrex’s appeals; Arthrex later coughed up $35 million to satisfy the judgment and failed to convince the U.S. Supreme Court review the case. A New Jersey federal judge tossed a lawsuit later brought by Arthrex.

In March, Stryker asked the PTAB for inter partes review, challenging 21 claims of KFx’s ‘311 patent. Yesterday the patent trial board rejected the request, citing the patent surviving its initial prosecution and a subsequent re-examination and the Arthrex lawsuit.

“We find that the asserted art was not a basis for rejection during prosecution or reexamination,” according to the PTAB decision. “The Arthrex litigation and, specifically, the evidence of secondary considerations developed therein, weighs in favor of denying institution.

“Despite knowing of the Arthrex litigation, [Stryker] did not address the secondary considerations evidence in its petition. We have cautioned petitioners in prior proceedings that petitions may be denied if they do not address known evidence of secondary considerations. [Stryker’s] failure to address the known evidence of secondary considerations further weighs in favor of denying institution,” the board decided.

It’s the second win in as many months for KFx over Stryker, which issued an IPR challenge to U.S. patent no. 8,951,287, also covering a “System and method for attaching soft tissue to bone.” In an August 19 decision, the PTAB ruled against initiating the review because Stryker failed to show any evidence that an obviousness challenge could succeed.