New study validates Guardant Reveal blood test’s effectiveness in monitoring chemotherapy response in solid tumours – Guardant Health

Guardant Health Inc. announced new data demonstrating that its Guardant Reveal blood test helps clinicians to assess the effectiveness of chemotherapy in patients with advanced solid tumors months earlier than conventional methods. This is the first robust clinical validation study of pan-cancer chemotherapy monitoring, published in the Journal of Liquid Biopsy. The study used a tissue-free, methylation-based ctDNA tumor fraction signal to track changes in cancer over time and provides real-world evidence that changes detected in a blood-based tumor signal correlate strongly with patient outcomes, offering oncologists a timely and non-invasive tool for monitoring cancer therapy.

The study showed that any decrease in tumor fraction signal after chemotherapy initiation was associated with both longer treatment duration and increased survival rates. Notably, patients who experienced a greater than 98% reduction in the tumor signal saw the most significant benefits. Conversely, a rise in the tumor signal identified disease progression up to 18 months earlier with a median lead time of 2.3 months – much earlier than standard clinical measures could detect.

“This study demonstrates the potential of a blood test to give oncologists an earlier and accurate look at whether chemotherapy is helping,” said Dr. Craig Eagle, Guardant Health Chief Medical Officer. “Guardant Reveal’s ability to detect molecular changes weeks or months before they show up on scans give doctors more time to adjust care and potentially spare patients from the toxicity of ineffective treatment.”

The majority of patients with metastatic solid tumors receive chemotherapy at some point during their treatment. Guardant Reveal interrogates nearly 30,000 methylated regions across the genome resulting in unparalleled precision for tracking and monitoring tumor burden in patients. Because the methylation-based tumor fraction test doesn’t require tumor tissue, Guardant Reveal can be used more broadly to monitor treatment response across multiple cancer types.

Citation:Rolfo CD et al. Chemotherapy response monitoring with DNA methylation-based ctDNA tumor fraction: Evidence from a real-world cohort of patients with advanced common solid malignancies.  J Liq Biopsy  2025, 10: 100442  https://doi.org/10.1016/j.jlb.2025.100442