Background
TwinStrand Biosciences and the University of Washington own patents covering duplex consensus sequencing (DCS) — a method of dramatically reducing the error rate of next-generation DNA sequencing. The core insight of DCS is to attach a unique molecular identifier (UMI) to each strand of a double-helix DNA molecule and sequence both strands independently, then compare the results: a true mutation shows up on both strands, while a sequencing error (appearing on only one strand) is filtered out. The result is roughly 10,000 times more accurate than conventional NGS, making it particularly valuable for detecting rare cancer-associated mutations circulating in the bloodstream.
In 2021, TwinStrand and the University of Washington sued Guardant Health, a leading liquid biopsy company, alleging that Guardant’s flagship Guardant360 CDx and related cancer screening products incorporated DCS technology without a license. Guardant Health countered before the Patent Trial and Appeal Board (PTAB), filing IPR petitions seeking to invalidate TwinStrand’s patents. The PTAB rejected Guardant’s invalidity challenges and confirmed the patent claims. The case proceeded to a jury trial in the District of Delaware.
On November 14, 2023, the jury returned a verdict finding that Guardant Health had willfully infringed U.S. Patent Nos. 10,287,631 and 10,760,127, and awarded $83.4 million in damages. Guardant filed post-trial motions seeking judgment as a matter of law (JMOL) on infringement and damages, and alternatively a new trial, arguing that the jury’s verdict was not supported by sufficient evidence.
The Court’s Holding
On June 16, 2026, the district court denied Guardant’s post-verdict motions in their entirety, refusing to set aside or reduce the jury’s $83.4 million verdict. The court concluded that the jury’s findings on infringement and willfulness were supported by substantial evidence, and that no error in the trial record warranted a new trial or a reduction in damages.
The court’s ruling leaves the $83.4 million compensatory verdict intact. Because the jury found willful infringement, TwinStrand may seek enhanced damages of up to three times the compensatory amount under 35 U.S.C. § 284, as well as attorney fees under 35 U.S.C. § 285 — issues the court will address in subsequent proceedings.
Key Takeaways
- Delaware’s denial of JMOL confirms that the jury’s infringement and willfulness findings were solidly supported by the trial record, clearing the way for potential treble damages and fee-shifting arguments in post-trial proceedings.
- The PTAB’s prior rejection of Guardant’s IPR challenges meant Guardant could not use PTAB invalidity findings as a backstop at trial, a strategy that proved fatal to its post-trial attack on the verdict.
- The duplex sequencing patents cover a method with broad applications in cancer detection, prenatal screening, and pharmaceutical development — this verdict is a strong signal that DCS-based liquid biopsy technologies require licensing from TwinStrand/UW or independent development of non-infringing alternatives.
- The case illustrates the compounding risk of continued infringement after receiving IPR-related notice: a jury that finds willfulness may award the full compensatory amount, after which treble damages and fees remain on the table.
Why It Matters
Liquid biopsy — using a blood draw to detect cancer-associated DNA circulating in the bloodstream — is one of the fastest-growing sectors of oncology diagnostics. Guardant Health is one of the largest companies in this space, with Guardant360 CDx being FDA-approved as a companion diagnostic for multiple cancer therapies. An $83.4 million verdict (with the prospect of trebling) in a single patent case is a significant financial exposure for any company, but especially so in a market where product reimbursement prices are set by regulatory bodies and competition is intense.
For patent holders in the diagnostics and genomics space, TwinStrand’s win provides a roadmap: patents on sequencing accuracy improvements can be enforced against downstream commercial products even when those products don’t commercially advertise the underlying methodology. For companies building on published academic sequencing methods, the case is a reminder that the gap between a published research technique and a commercialized clinical test may not insulate a product from patent liability if the underlying method is covered by issued claims.