• Tissue-free Guardant Reveal test identifies disease progression up to 18 months earlier than standard clinical measures in patients with advanced cancer
• Longitudinal circulating tumor DNA (ctDNA) monitoring across multiple timepoints provides a more accurate prediction of treatment response and disease progression than a single on-treatment analysis, reinforcing the clinical value of serial testing

Guardant Health, Inc. (Nasdaq: GH), a leading precision oncology company, today 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.

About Guardant Health

Guardant Health is a leading precision oncology company focused on guarding wellness and giving every person more time free from cancer. Founded in 2012, Guardant is transforming patient care and accelerating new cancer therapies by providing critical insights into what drives disease through its advanced blood and tissue tests, real-world data and AI analytics. Guardant tests help improve outcomes across all stages of care, including screening to find cancer early, monitoring for recurrence in early-stage cancer, and treatment selection for patients with advanced cancer. For more information, visit guardanthealth.com and follow the company on LinkedIn, X (Twitter) and Facebook.

Guardant Health Forward-Looking Statements

This press release contains forward-looking statements within the meaning of federal securities laws, including statements regarding the potential utilities, values, benefits and advantages of Guardant Health’s liquid biopsy tests or assays, which involve risks and uncertainties that could cause the actual results to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are based on current expectations, forecasts and assumptions, and actual outcomes and results could differ materially from these statements due to a number of factors. These and additional risks and uncertainties that could affect Guardant Health’s financial and operating results and cause actual results to differ materially from those indicated by the forward-looking statements made in this press release include those discussed under the captions “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operation” and elsewhere in its Annual Report on Form 10-K for the year ended December 31, 2024 and in its other reports filed with or furnished to the Securities and Exchange Commission. The forward-looking statements in this press release are based on information available to Guardant Health as of the date hereof, and Guardant Health disclaims any obligation to update any forward-looking statements provided to reflect any change in its expectations or any change in events, conditions, or circumstances on which any such statement is based, except as required by law. These forward-looking statements should not be relied upon as representing Guardant Health’s views as of any date subsequent to the date of this press release.

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