Guardant Health to Share New Research Demonstrating Value of Liquid Biopsy Tests, Real-world Data and AI Analytics in Tailoring Treatment Approaches for Breast Cancer at 2024 San Antonio Breast Cancer

Spotlight presentation using Guardant Reveal™ test suggests ctDNA has potential to predict sensitivity to endocrine therapy and long-term outcomes in HR+ breast cancer

Guardant Health to Share New Research Demonstrating Value of Liquid Biopsy Tests, Real-world Data and AI Analytics in Tailoring Treatment Approaches for Breast Cancer at 2024 San Antonio Breast Cancer Symposium

Investor Contact:
Zarak Khurshid
investors@guardanthealth.com

Media Contact:
Michael Weist
press@guardanthealth.com
+1 317-371-0035

Guardant Health, Inc. (Nasdaq: GH), a leading precision oncology company, today announced the company and its research collaborators will present data demonstrating the benefits of its precision oncology tests, real-world clinical-genomic database and AI analytics in optimizing therapy selection, identifying resistance mutations, and predicting long-term outcomes at the San Antonio Breast Cancer Symposium (SABCS) 2024 in San Antonio, Texas, Dec. 10-13, 2024.

Guardant and its research partners will present eight posters, including an SABCS Poster Spotlight featuring the use of the Guardant Reveal test, a tissue-free epigenomic assay, to investigate the dynamics of circulating tumor DNA (ctDNA) during neoadjuvant endocrine therapy in HR+ early breast cancer. Study findings suggest that ctDNA has the potential to provide valuable insights into tumor burden, sensitivity to endocrine therapy, and the emergence of endocrine resistance mutations. The investigators conclude that ctDNA could be a valuable tool in predicting long-term outcomes and in tailoring treatment approaches.

“Working together with our research collaborators, we continue to establish the important role of Guardant’s precision oncology portfolio in informing treatment selection and monitoring for recurrence and therapeutic response,” said Craig Eagle, M.D., chief medical officer at Guardant Health. “We look forward to sharing new studies at SABCS that show how Guardant is working with researchers and cancer care teams to improve outcomes for people living with breast cancer.”

Guardant Health and collaborator poster presentations at SABCS 2024

Wednesday, December 11 \| 7:00-8:30 am \| Hemisfair Ballroom 1-2
Abstract	Title	Product
PS7-05	SABCS Poster Spotlight Impact of prior treatment, ESR1 mutational (ESR1m) landscape, and co-occurring PI3K pathway status on real-world (RW) elacestrant outcomes in patients (pts) with hormone receptor-positive (HR+)/HER2-negative advanced breast cancer (aBC)	GuardantINFORM™
Wednesday, December 11 \| 12:30 - 2:00 pm \| Halls 2-3
P1-01-24	Genomic comparison of rapid vs. typical progressors on CDK4/6 inhibitor treatment in advanced breast cancer	GuardantINFORM
P1-05-30	A statistical model for integration of on-treatment circulating tumor DNA dynamics and prediction of outcomes in patients with ER+/HER2- metastatic breast cancer	Guardant Infinity™
P1-10-05	Real-world molecular profiling after CDK4/6 inhibition in advanced breast cancer: analysis of the SOLTI-1903 HOPE study	Guardant360® CDx
Wednesday, December 11 \| 5:30-7:00 pm \| Halls 2-3
P2-05-20	Tissue-free minimal residual disease testing in 2,000 consecutive patients with breast cancer: real-world data and case report	Guardant Reveal
Thursday, December 12 \| 7:00-8:30 am \| Stars at Night 3-4
PS9-04	SABCS Poster Spotlight Evaluating racial genomic differences in de novo metastatic breast cancer utilizing ctDNA: results from a large multi-center consortium	Guardant360
PS9-08	SABCS Poster Spotlight Ultra-sensitive detection of circulating tumor DNA (ctDNA) in patients (pts) undergoing neoadjuvant endocrine therapy for hormone receptor-positive (HR+) early breast cancer (BC)	Guardant Reveal
Thursday, December 12 \| 5:30-7:00 pm \| Halls 2-3
P4-01-19	Clinical impact of MRD detection via ctDNA tumor-agnostic assay in early-stage breast cancer patients: a real-world experience	Guardant Reveal

The full abstracts for Guardant Health and a list of all abstracts being presented at SABCS 2024 can be found on the SABCS website.

For information and updates from the conference, visit booth 1424 and follow Guardant Health on LinkedIn, X (Twitter) and Facebook.

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.

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, 2023, and in its other reports filed with or furnished to the Securities and Exchange Commission thereafter. 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.