TwinStrand Biosciences (TwinStrand), the pioneer in Duplex Sequencing® technology, today announced that the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB) has again rejected Guardant Health, Inc.’s (Nasdaq: GH) challenge to a core patent underlying Duplex Sequencing. In an Oct. 14, 2026, Final Written Decision on remand from the U.S. Court of Appeals for the Federal Circuit, the PTAB ruled in favor of the University of Washington (UW), determining that Guardant Health failed to establish the unpatentability of any of the 30 challenged claims of U.S. Patent No. 10,760,127. The ‘127 patent is owned by UW and exclusively licensed to TwinStrand.

This decision follows an October 2023 PTAB ruling in favor of UW in the inter partes review of this patent, which Guardant Health appealed. In January 2026, the Federal Circuit directed the PTAB to reconsider the challenge under a different legal framework as identified by the appeals court. Applying that analysis, the PTAB has rejected Guardant Health’s challenge in its entirety.

“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. “This Final Written Decision is a substantial, meaningful step forward for our team. We stand unwaveringly behind the intellectual property at the core of Duplex Sequencing and will continue to seek victory against willful infringement of our patent rights.”

The ’127 patent is one of two patents at issue in the patent infringement litigation 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 UW. That judgment preserved a November 2023 jury verdict finding that Guardant Health willfully infringed the ’127 patent and U.S. Patent No. 10,287,631, and 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 all covered products and services through March 2033, when these patents expire. A separate re-examination proceeding involving the ’631 patent remains ongoing before the U.S. Patent and Trademark Office.

About TwinStrand Biosciences

TwinStrand Biosciences is a precision genomics company advancing highly accurate DNA sequencing through its patented TwinStrand Duplex Sequencing® technology, originally developed at the University of Washington. Duplex Sequencing achieves more than 10,000-fold greater accuracy than conventional next-generation sequencing by independently sequencing and comparing both complementary strands of each DNA molecule. This enables reliable detection of ultra-low-frequency genetic variants that conventional methods often cannot distinguish from background sequencing errors. The technology supports applications across oncology, molecular diagnostics, genetic toxicology and drug development. TwinStrand collaborates with leading pharmaceutical companies, molecular diagnostics developers, academic institutions and research organizations, and its intellectual property portfolio includes more than 150 issued patents and patent applications worldwide. For more information, visit www.twinstrandbio.com.

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