Clinical Report: FDA approves serial liquid biopsy testing

Overview

The FDA has approved Guardant360 CDx as a companion diagnostic for identifying ESR1 mutations in patients with hormone receptor-positive, HER2-negative advanced breast cancer. This approval allows for testing every three months during therapy to guide treatment decisions, particularly the switch to camizestrant upon detection of mutations.

Background

The identification of ESR1 mutations in breast cancer is crucial as these mutations can lead to resistance against standard therapies. The ability to detect these mutations early through liquid biopsy allows for timely adjustments to treatment regimens. The approval of Guardant360 CDx represents a significant advancement in personalized medicine for breast cancer management.

Data Highlights

Key Findings

• Guardant360 CDx is approved for detecting ESR1 mutations in breast cancer patients.
• Testing is recommended every 3 months during therapy.
• Patients switching to camizestrant had a 56% lower risk of disease progression or death.
• There was a 47% reduction in deterioration of global health status and quality of life with ctDNA-guided treatment.
• This approval marks the 29th companion diagnostic indication for Guardant360 globally.

Clinical Implications

Healthcare providers should consider implementing Guardant360 CDx testing in eligible patients to monitor for ESR1 mutations.

Conclusion

The FDA's approval of Guardant360 CDx highlights the importance of liquid biopsy in managing advanced breast cancer.

Related Resources & Content

1. Guardant Health, FDA, 2026 -- FDA grants accelerated approval to camizestrant with a CDK4/6 inhibitor for ESR1-Mutated HR-positive, HER2-negative locally advanced or metastatic breast cancer
2. MDSpire News, 2026 -- FDA Approves Expanded Liquid Biopsy Panel
3. The ASCO Post, 2020 -- FDA Pipeline: Approval for First Liquid Biopsy Next-Generation Sequencing Companion Diagnostic; Designations in Ovarian Cancer, Leukemia, and Lymphoma
4. The ASCO Post, 2026 -- ASCO Publishes First Guideline on ctDNA Testing in Solid Tumors and Lymphoma
5. The ASCO Post — FDA Pipeline: Approval for First Liquid Biopsy Next-Generation Sequencing Companion Diagnostic; Designations in Ovarian Cancer, Leukemia, and Lymphoma
6. the pathologist — Decentralized Liquid Biopsy Testing for Comprehensive Genomic Profiling
7. FDA grants accelerated approval to camizestrant with a CDK4/6 inhibitor for ESR1-Mutated HR-positive, HER2-negative locally advanced or metastatic breast cancer | FDA
8. ASCO Publishes First Guideline on ctDNA Testing in Solid Tumors and Lymphoma - The ASCO Post