BioTech IP Review

Microsatellite Instability Detection in Cell-free DNA

Assignee: Guardant Health, Inc.
Patent Number: 12,344,902
Filed: (Priority details typically earlier but reported in 2025)
Patent Issued: July 1, 2025
Inventors: Aliaksandr Artsiomenka, Marcin Pawel Sikora, Catalin Barbacioru, Darya Chudova, Martina I. Lefterova

What It Covers

This patent covers methods for detecting microsatellite instability (MSI) in cell-free DNA (cfDNA) — a powerful biomarker of genomic instability in cancer patients. MSI status helps guide diagnosis, prognosis, and therapeutic decisions, especially for immunotherapy responsiveness in various cancers.

Key points of the invention include:

  • Analysis of cfDNA: Techniques for measuring repeat lengths at microsatellite loci using cfDNA extracted from a blood sample rather than invasive tissue biopsies.
  • Quantification of multiple length variants: Comparing different microsatellite repeat lengths at multiple loci to infer MSI status.
  • Liquid biopsy application: Specifically tailored to non-invasive “liquid biopsy” workflows that sequence and interpret circulating tumor DNA (ctDNA), preserving Guardant’s edge in blood-based cancer diagnostics.

Why This Patent Is Important

1. Core to Guardant’s Precision Oncology Platform

Guardant Health is best-known for its liquid biopsy tests — like Guardant360 — which profile cancer mutations via blood samples. This patent strengthens its IP around advanced genomic biomarkers (MSI) that inform treatment decisions without tissue biopsies, expanding clinical utility.

2. Clinical and Commercial Value

Microsatellite instability is a well-established biomarker for immunotherapy eligibility (e.g., checkpoint inhibitors). Methods that reliably detect MSI from blood can streamline patient stratification, enhance test value, and support broader reimbursement. Guardant’s liquid biopsy tests are increasingly used in clinical oncology management and therapeutic selection.

3. Competitive Advantage in a High-Growth Market

Improvements in non-invasive cancer diagnostics are a fast-growing, multi-billion-dollar space. Blood-based MSI detection positions Guardant to compete not only in mutation profiling but also in predictive biomarker markets, which can command higher test prices and clinical demand. Guardant’s expanded liquid biopsy use cases (e.g., subtyping, methylation profiling) were highlighted in its 2025 product expansions.

4. Strategic Defense & Legal Landscape

Guardant also engages actively in IP enforcement and defense (e.g., ongoing suits and petitions related to bioinformatic and sequencing patents), which underscores the strategic importance of a strong patent portfolio for protecting market share and licensing leverage.

Summary

U.S. Patent No. 12,344,902, issued July 1, 2025, protects methods for determining microsatellite instability (MSI) from cell-free DNA samples, a key biomarker in cancer diagnosis and treatment selection using non-invasive liquid biopsy tests. This patent supports Guardant Health’s core precision oncology products and enhances the commercial and clinical value of its genomic testing platform in the rapidly expanding cancer diagnostics market.

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