• Guardant360 CDx can now help identify cancer mutations earlier and drive improved patient outcomes in major global geographies
• This latest approval marks Guardant’s 31^st CDx approval

Guardant Health, Inc. (Nasdaq: GH), a leading precision oncology company, today announced that Guardant360^® CDx has received CE-marking under Europe’s in Vitro Diagnostic Medical Devices Regulation as a companion diagnostic (CDx) to identify patients with estrogen receptor (ER)-positive, HER2-negative locally advanced or metastatic breast cancer who may benefit from treatment with ETCAMAH^™ (camizestrant), AstraZeneca’s next-generation oral selective estrogen receptor degrader (SERD) and complete ER antagonist. Approval in Europe reinforces Guardant Health's commitment to enabling practice-changing ongoing monitoring across the world's largest healthcare markets.

With Guardant 360 CDx, clinicians can test for ESR1 mutations in tumors through a simple blood draw, ahead of disease progression. This approach reinforces the transformative role of liquid biopsy in guiding therapy decisions earlier in a breast cancer patient’s journey. The European approval follows prior regulatory approvals of Guardant360 CDx as a companion diagnostic for ETCAMAH in the United States and Japan.

“Guardant360 CDx offers molecular insights that can support informed treatment decisions for patients with advanced breast cancer, addressing the disease before it gets out of control,” said Helmy Eltoukhy, Guardant Health chairman and co-CEO. “What is even more exciting is that we see tremendous potential for this type of testing protocol to transform the treatment of other cancer types to change the future of oncology.”

This approval marks a significant milestone for the company, representing the third CDx approval for ETCAMAH and the 31^st CDx approval for Guardant Health. The company continues to expand the platform’s reach and increasing clinical utility.

About Guardant360^® CDx

Guardant360 CDx is the first FDA-approved liquid biopsy for comprehensive genomic profiling. It detects multiple genomic alterations across all solid tumors and is approved as a companion diagnostic for therapies in non-small cell lung cancer, breast cancer, and colorectal cancer.

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, 2025 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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