Guardant Health to Share Data Supporting Critical Role of Blood-Based Testing in Improving Cancer Screening Adherence at ACG 2025

• Expanded cohort reiterates strong adherence rate of over 90% for Shield blood-based colorectal cancer screening test
• Survey findings show eligible individuals prefer a blood test for colorectal cancer and lung cancer compared with traditional screening methods

Guardant Health, Inc. (NASDAQ:GH), a leading precision oncology company, today announced the company and its research collaborators will present data showing the critical role of blood-based testing in increasing cancer screening adherence at the American College of Gastroenterology (ACG) 2025 Annual Meeting in Phoenix, Arizona taking place Friday, October 24 – Wednesday, October 29, 2025.

Building off findings from Guardant Health's 2023 ACG abstract, a study of an expanded cohort of 20,000 patients confirmed findings from earlier reports on the effectiveness of the Shield blood-based screening test in improving adherence to colorectal cancer (CRC) screening. Shield is the first and only blood test to receive FDA approval as a primary screening option for colorectal cancer in average-risk adults aged 45 and older. The findings demonstrated an over 90% adherence rate for Shield, tracking well above average screening adherence for overall CRC testing which ranges from 28-71%. ^1-4

A separate study led by researchers at Cedars Sinai found that individuals prefer a blood test for colorectal cancer and lung cancer over other methods, showing the potential for an innovative blood test like Shield to increase the overall screening rate in lung cancer screening. The survey found that more screening-eligible individuals (43.9%) prefer to do a blood test for colorectal cancer and lung cancer compared to traditional screenings.

"Today's research reinforces what Guardant has long believed: blood-based cancer screening is the future," said Dr. Craig Eagle, Chief Medical Officer at Guardant Health. "These studies highlight the power of a simple blood test in addressing today's gaps in colorectal cancer screening adherence and potential to expand to an even broader population looking for a more pleasant option for their regular lung cancer screening. We're eager to present these findings along with our research collaborators at the ACG meeting and proud to offer Shield, an FDA-approved test, as an accessible and convenient alternative to traditional screening methods."

Guardant Health and collaborator presentations at ACG 2025

The full abstracts for Guardant Health and a list of all abstracts being presented at the ACG Annual Meeting can be found here.

About Shield

Shield is a non-invasive, blood-based screening test that detects alterations associated with colorectal cancer in the blood. It is intended as a screening test for individuals at average risk for the disease, age 45 or older, and is not intended for individuals at high risk for colorectal cancer. The Shield test can be considered in a manner similar to guideline-recommended non-invasive CRC screening options and can be completed during any healthcare visit. A positive Shield result raises concern for the presence of colorectal cancer or advanced adenoma and the patient should be referred for colonoscopy evaluation.

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.

¹ Denberg TD, Melhado TV, Coombes JM, et al. Predictors of nonadherence to screening colonoscopy. J Gen Intern Med. 2005;20(11):989-995.

² Gellad ZF, Stechuchak KM, Fisher DA, et al. Longitudinal adherence to fecal occult blood testing impacts colorectal cancer screening quality. Am J Gastroenterol. 2011;106(6):1125-1134.

³ Inadomi JM, Vijan S, Janz NK, et al. Adherence to colorectal cancer screening: a randomized clinical trial of competing strategies. Arch Intern Med. 2012;172(7):575-582.

⁴ Exact Sciences. Third quarter 2019 webcast and conference call. Updated October 29, 2019. https:/ investor.exactsciences.com/investor-relations/events-and-presentations/event-details/2019/Third-Quarter-2019-Webcast-Conference-Call/default.aspx

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