The U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB) has issued a second ruling in favor of the University of Washington and TwinStrand Biosciences, rejecting Guardant Health's (Nasdaq: GH) challenge to all 30 claims of U.S. Patent No. 10,760,127, according to a statement from TwinStrand.

The Oct. 14, 2026, Final Written Decision came on remand from the U.S. Court of Appeals for the Federal Circuit, which in January 2026 had directed the PTAB to reconsider the challenge under a different legal framework. Applying that framework, the PTAB again determined that Guardant Health failed to establish the unpatentability of any of the 30 challenged claims. The PTAB had first ruled in favor of the University of Washington in October 2023.

The '127 patent is owned by the University of Washington and exclusively licensed to TwinStrand. It is one of two patents at issue in a patent infringement case TwinStrand brought against Guardant Health in the U.S. District Court for the District of Delaware.

Final judgment in that case was entered in August 2026 in favor of TwinStrand and the University of Washington, preserving a November 2023 jury verdict that found Guardant Health willfully infringed the '127 patent and U.S. Patent No. 10,287,631. The judgment awarded more than $245.2 million in damages, accrued royalties, and interest for infringement through May 2026. Guardant Health was also ordered to pay an ongoing royalty of 6% on covered products and services through March 2033, when the patents expire.

A separate re-examination proceeding involving the '631 patent remains ongoing before the U.S. Patent and Trademark Office.

"Twice now the Patent Trial and Appeal Board has examined Guardant Health's challenge to the '127 patent, most recently under the precise framework identified by the Federal Circuit, and the outcome remains unchanged," said Chad Waite, chair of the TwinStrand board of directors.