Guardant Health to Showcase New Data at San Antonio Breast Cancer Symposium 2022 Demonstrating Utility of Its Blood Tests for Advanced-stage Breast Cancer Patients

Guardant Health, Inc. (Nasdaq: GH), a leading precision oncology company, announced today that new data from its portfolio of blood tests will be presented at the 2022 San Antonio Breast Cancer Symposium, December 6-10 in San Antonio, Texas. The six poster presentations highlight the use of the Guardant360® blood test and the GuardantINFORMtm real-world evidence dataset to identify critical biomarkers and acquired co-mutations, track associated treatment patterns and clinical outcomes, and monitor molecular response to therapy based on specific breast cancer driver mutations.

"We look forward to sharing new data at the San Antonio Breast Cancer Symposium demonstrating the utility of our blood tests to increase the understanding of potential biomarker targets and the mechanisms of molecular response in patients with advanced breast cancer," said Helmy Eltoukhy, Guardant Health co-CEO. "The presentations will show how data from comprehensive genomic profiling tests provide critical insights that can contribute to the development of more effective therapies and improved patient outcomes."

Full List of Guardant Health Presentations

Guardant360

• ctDNA molecular response based on breast cancer driver mutations predicts progression in aromatase inhibitor-sensitive first line treatment of oestrogen receptor-positive (ER+) HER2-negative (HER2-) advanced breast cancer (Poster PD17-02)
• TRK inhibitor in a patient with metastatic triple negative breast cancer and NTRK fusions identified via cell-free DNA analysis (Poster P5-02-13)
• Cell-free DNA detection of GATA3 mutations in metastatic hormone receptor positive breast cancer: a multi-institutional analysis of incidence, co-mutations, and clinical outcomes (Poster P5-02-07)
• Co-occurring alterations in PALB2 germline carriers identified by liquid biopsy in patients with advanced breast cancer (Poster P5-03-18)
• Characterization of the genomic landscape of breast carcinoma patients with NF1 alterations using comprehensive cell-free tumor DNA next-generation sequencing (Poster P5-05-03)

Guardant360 and GuardantINFORM

• Real-world second-line treatment patterns and associated clinical outcomes for 2795 patients with advanced HR+ HER2- breast cancer treated with first-line CDK4/6 inhibitors (Poster P4-01-18)

The full abstracts are available on the official SABCS 2022 website.

About Guardant Health

Guardant Health is a leading precision oncology company focused on helping conquer cancer globally through use of its proprietary tests, vast data sets and advanced analytics. The Guardant Health oncology platform leverages capabilities to drive commercial adoption, improve patient clinical outcomes and lower healthcare costs across all stages of the cancer care continuum. Guardant Health has commercially launched Guardant360®, Guardant360 CDx, Guardant360 TissueNexttm, Guardant360 Responsetm, and GuardantOMNI® tests for advanced stage cancer patients, and Guardant Revealtm for early-stage cancer patients. The Guardant Health screening portfolio, including the Shieldtm test, aims to address the needs of individuals eligible for cancer screening. For more information, visit guardanthealth.com and follow the company on LinkedIn and Twitter.

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, 2021 and in its other reports filed with 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.