Research reinforces the significance of genomic and epigenomic profiling approaches to characterize tumor types, identify biomarkers, and support risk stratification
Presentations reflect Guardant’s strong biopharma and academic collaborations, along with public-private partnerships in Europe

Guardant Health, Inc. (NASDAQ:GH), a leading precision oncology company, today announced that the company and its research collaborators will present 25 abstracts—including five rapid oral presentations—demonstrating advances in methylation-based circulating tumor DNA (ctDNA) monitoring and liquid biopsy technology across lung, colorectal, and gastric cancers at the European Society for Medical Oncology (ESMO) Congress 2026, taking place October 23-27 in Madrid, Spain.

The studies span Guardant's cancer portfolio, including tissue-free minimal residual disease (MRD) surveillance, treatment response, and resistance research. Significant studies were conducted independently by industry collaborators, academic institutions, and Guardant’s public-private partners using the company’s technologies and/or real-world data, underscoring the wide adoption of its platform across the research community.

"At ESMO, we will showcase how InfinityAI is advancing our portfolio, strengthening the clinical relevance of our data, and delivering value to patients, healthcare professionals, and biopharma partners," said Helmy Eltoukhy, Guardant Health chairman and co-CEO. "We look forward to presenting new findings and connecting with the oncology community to discuss how Guardant’s solutions can advance cancer care globally."

Key data that will be presented include:

Rapid Oral 283RO: Assessing bemarituzumab in patients with advanced gastric and gastroesophageal junction cancer by fibroblast growth factor receptor 2 (FGFR2) amplification status in the FORTITUDE study, which suggests that FGFR2 amplification may identify a more treatment-sensitive subgroup.

Friday, Oct. 23, 2026, Session: 4:15-5:45 p.m., Presentation: 5:19-5:24 p.m., Location: Almeria Auditorium - Hall 9

Rapid Oral LBA73: Evaluating ctDNA-guided treatment intensification in untreated advanced or metastatic EGFR-mutant non-small cell lung cancer (NSCLC) to identify patients who may benefit from intensified first-line therapy in the PACE-LUNG study—a multicenter, Phase II trial of additional chemotherapy for patients with persistent EGFR-mutant ctDNA in plasma at Week 3 after starting first-line osimertinib.

Saturday, October 24, 2026, Session: 8:30-10 a.m., Presentation: 8:30-8:35 a.m., Location: Almeria Auditorium - Hall 9

Rapid Oral 2636RO: Characterizing resistance mechanisms and predictors of early progression and long-term response to lorlatinib from the CROWN study. Findings suggest that baseline genomic complexity and on-treatment changes in methylation-based tissue-free assays may help identify patients at risk of early progression.

Saturday, Oct. 24, 2026, Session: 8:30-10 a.m., Presentation: 9:05-9:10 a.m., Location: Almeria Auditorium - Hall 9

Poster 4403P: Using serial Guardant360^® Liquid testing in a Phase 2 study with MD Anderson to examine clonal and subclonal resistance during anti-EGFR rechallenge in metastatic colorectal cancer to distinguish genuine resistance evolution from changes caused by fluctuating ctDNA levels, potentially improving patient selection for anti-EGFR rechallenge.

Friday, October 23, 2026, Session: 3:15-4 p.m.

Poster 2566P: Exploring post-surgical MRD and pathological complete response (pCR) after perioperative nivolumab in resectable Stage III NSCLC. In this exploratory analysis from NADIM II, pCR was associated with MRD negativity and excellent 5-year survival. In non-pCR patients, MRD negativity identified patients with favorable long-term outcomes, whereas detectable MRD defined a high-risk subgroup with early recurrence.

Monday, October 26, 2026, Session: 12-12:45 p.m.

Additional Guardant Health presentations at ESMO 2026

Abstract	Full abstract title	Session details
Poster 424P	Impact of blood draw weekday on turnaround time of Guardant360^®CDx liquid biopsy: A real-world analysis	Basic science Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 1026P	Longitudinal ctDNA monitoring and radiological response to targeted therapies in early-phase clinical trials	Developmental therapeutics Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 3275P	Clinical utility and interpretation challenges of circulating comprehensive genomic profiling in routine oncology practice	Pathology and molecular pathology Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 4279P	Trastuzumab deruxtecan vs physician’s choice of chemotherapy in HR+, HER2-low metastatic breast cancer: A DESTINY-Breast06 ctDNA molecular response analysis	Translational research and biomarkers Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 4311P	Genomic landscape of cancer of unknown primary: Prognostic stratification through molecular profiling	Translational research and biomarkers Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 4386P	Beyond HER2 IHC: ERBB2 RNA-ISH stratifies benefit from T-DXd combinations	Translational research and biomarkers Friday, October 23, 2026 Session: 3:15-4 p.m.
Poster 8P	Clinical efficacy and predictive biomarkers of mTOR inhibition combined with endocrine therapy following progression on PI3K inhibitors in hormone receptor–positive metastatic breast cancer	Advanced breast cancer, other Saturday, Oct. 24, 2026 Session: 12-12:45 p.m.
Poster 45P	Real-world elacestrant outcomes in ESR1-mutant HR+/HER2− metastatic breast cancer: A two-center NHS audit	Advanced breast cancer, other Saturday, October 24, 2026 Session: 12-12:45 p.m.
Poster 708P	Clinical and molecular characteristics of leptomeningeal disease in metastatic breast cancer patients: A prospective observational registry study	CNS tumors Saturday, October 24, 2026 Session: 12-12:45 p.m.
Rapid oral 787RO	ctDNA-guided re-treatment with encorafenib and cetuximab in patients with chemorefractory BRAFV600E mutated metastatic colorectal cancer (mCRC): The proof-of-concept single arm phase II BRICKET trial by GONO	Rapid oral: Gastrointestinal tumors, lower digestive Saturday, October 24, 2026 Session: 2:45-4:15 p.m. Presentation: 2:45-2:50 p.m. Location: Alicante Auditorium - Hall 6
Poster 805P	Baseline ctDNA and the efficacy of staged combination with encorafenib + binimetinib + cetuximab following encorafenib + cetuximab in patients with BRAF V600E-mutant mCRC from BAYONET trial	Colon cancer Sunday, October 25, 2026 Session: 12-12:45 p.m.
Rapid oral 3718RO	Molecular response in KIT circulating ctDNA from StrateGIST 1: A phase 1/1b study of velzatinib (IDRX-42) in patients with advanced gastrointestinal stromal tumors	Rapid oral: Sarcoma Monday, October 26, 2026 Session: 8:30-10 a.m. Presentation: 8:35-8:40 a.m. Malaga Auditorium - Hall 3
LBA - 4037	ctDNA negative hyperselection as an effect modifier of treatment sequence efficacy in left-sided RAS wild-type mCRC: pre-specified exploratory analysis of the CR-SEQUENCE	TBD
LBA 2882eP	ctDNA assessment in patients with CLDN18.2+, HER2−, locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma in SPOTLIGHT	TBD
ePoster-2813eP	A decade of ctDNA-NGS in NSCLC: Real-world evolution of actionability and liquid-first clinical use	ePoster: NSCLC, metastatic
ePoster- 4548eP	Combined cfDNA and ctDNA analysis improves prognostic models in patients referred for early-phase clinical trials	ePoster: Translational research and biomarkers
ePoster- 2734eP	Clinical significance of comprehensive genomic profiling after negative initial CDx testing in advanced NSCLC	ePoster: NSCLC, metastatic
ePoster TiP-3584eTiP	Consolidation XELOX plus dostarlimab after chemoradiation with optional adjuvant dostarlimab in pMMR/MSS or MSI-low locally advanced rectal cancer: The IMMUNOSTAR phase II randomized trial (GOIRC-02-2024)	ePoster Trial in progress: Rectal and anal cancer
ePoster-2783eP	Sequential liquid biopsy in advanced NSCLC	ePoster: NSCLC, metastatic
ePoster-4185eP	The value of liquid biopsy in pleural mesothelioma as a biomarker strategy in clinical trials selection	ePoster: Thoracic malignancies, other

The full abstracts for Guardant Health at ESMO 2026 can be found on the ESMO website.

Since 2020, Guardant has established public-private partnerships (PPPs) with leading healthcare institutions and cancer centers in Europe including The Royal Marsden NHS Foundation Trust (UK), Vall d’Hebron Institute of Oncology (Spain), and Policlinico Gemelli (Italy) to localize advanced diagnostic testing, generate clinical/economic evidence, and ultimately expand reimbursement and adoption. These partnerships make it possible to deliver high quality, clinical grade testing, similar to tests administered in the U.S., with local validation supporting research, delivering faster diagnoses, and increasing access to targeted treatments.

To learn more about the PPPs and Guardant Health during ESMO, visit the team at Booth #8058.

About Guardant360^® Liquid

Guardant360 Liquid is a blood-based test that analyzes tumor DNA fragments circulating in the blood (cfDNA) to identify genetic mutations in advanced solid tumors, helping oncologists find targeted therapies. It offers an alternative to tissue biopsies, providing comprehensive genomic profiling (CGP) to guide personalized treatment for a wide range of solid cancers including lung, breast, colorectal, and prostate cancer. Guardant360 Liquid is guideline-complete across all advanced solid tumors, and has been clinically validated in more than 1,500 publications and research abstracts.

About Guardant Reveal^®

Guardant Reveal is a tissue-free liquid biopsy test that detects minimal residual disease (MRD) and monitors recurrence in early-stage colorectal, breast, and lung cancers, helping oncologists guide treatment decisions. In addition to MRD detection, Reveal can be used for late-stage therapy response monitoring for patients with solid tumors. Guardant Reveal therapy response monitoring can be initiated at any time during a patient’s treatment journey, offering clinicians flexibility and actionable insights.

The first clinical-validation study of pan-cancer chemotherapy monitoring published in The Journal of Liquid Biopsy showed that Guardant Reveal predicts long-term patient benefit up to 18 months earlier than standard clinical measures.

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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Investor Contact:

Zarak Khurshid

investors@guardanthealth.com

Media Contact:

Meaghan Smith

press@guardanthealth.com