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April, 09, 2020

Study Shows Guardant360 Test Identifies Predictors of Response to PIK3CA Inhibitors in Women with HR+ Metastatic Breast Cancer

REDWOOD CITY, Calif., April 09, 2020 (GLOBE NEWSWIRE) -- Many women with metastatic hormone receptor-positive (HR+) breast cancer have experienced improved clinical outcomes with the recent introduction of alpelisib, a PIK3CA inhibitor. A new study led by Memorial Sloan Kettering Cancer Center and published in Nature Cancer1 demonstrates that the Guardant360® liquid biopsy test effectively identified patients with PIK3CA mutations along with other mutations that correlate with treatment resistance.

The phase I/II study (NCT01870505), a longitudinal analysis of tumor and blood-based circulating tumor DNA (ctDNA) in metastatic patients treated with alpelisib plus fulvestrant showed 89 percent concordance between tissue and blood for PIK3CA mutations. In the study, the Guardant360 liquid biopsy test also detected significantly more potential resistance alterations compared to tissue biopsy testing. These findings build upon the plasmaMATCH study results2 showing the importance of using a liquid biopsy test to conduct comprehensive genomic testing in metastatic breast cancer and to overcome the limitations of tissue to evaluate tumor heterogeneity.

“While the introduction of PI3K inhibitors in combination with endocrine therapy has made a significant difference in improving progression-free survival, the findings of this new study indicate the need for more comprehensive genomic profiling in hormone receptor-positive metastatic breast cancer patients,” said Pedram Razavi, MD, PhD, a lead study investigator, and a medical oncologist at Memorial Sloan Kettering Cancer Center. “Testing more broadly beyond PIK3CA can help identify potential mechanisms of resistance to therapy and determine those patients most likely to respond to a PI3K inhibitor.”

“Given the prevalence of bone metastases in metastatic breast cancer, observed in approximately one-third of patients in this study, the Guardant360 liquid biopsy test can also potentially help to overcome the challenges associated with performing bone biopsies that often yield insufficient material for biomarker analysis,” said AmirAli Talasaz, PhD, Guardant Health president.

The Guardant360 test is increasingly being used to guide treatment in metastatic breast cancer as the number of treatment-relevant genomic alterations continues to grow. Using next-generation sequencing, Guardant360 analyzes 74 genes using cell-free tumor DNA from blood samples. The Guardant360 test is broadly covered by Medicare for use across the vast majority of advanced solid tumors, including patients with metastatic breast cancer.

The publication titled, “Alterations in PTEN and ESR1 promote clinical resistance to alpelisib plus aromatase inhibitors.” can be found here: doi:10.1038/s43018-020-0047-1.

About Guardant Health
Guardant Health is a leading precision oncology company focused on helping conquer cancer globally through use of its proprietary blood 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 launched liquid biopsy-based Guardant360 and GuardantOMNI tests for advanced stage cancer patients. These tests fuel development of its LUNAR program, which aims to address the needs of early stage cancer patients with neoadjuvant and adjuvant treatment selection, cancer survivors with surveillance, asymptomatic individuals eligible for cancer screening and individuals at a higher risk for developing cancer with early detection.

Forward-looking Statements
This press release contains forward-looking statements within the meaning of federal securities laws, including statements regarding the Guardant360 test’s ability to overcome the challenges associated with performing bone biopsies for metastatic breast cancer biomarker analysis, 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. Such risks and uncertainties include those discussed under the caption “Risk Factors” in Guardant Health’s Annual Report on Form 10-K for the year ended December 31, 2019, and in its other reports filed with the Securities and Exchange Commission. These forward-looking statements are based on current expectations, forecasts, assumptions and information available to Guardant Health as of the date hereof, and actual outcomes and results could differ materially from these statements due to a number of factors, 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. Investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Guardant Health.

Investor Contact:
Carrie Mendivil
investors@guardanthealth.com

Media Contact:
Anna Czene
press@guardanthealth.com

Becky Lauer
becky.lauer@uncappedcommunications.com

References

  1. Razavi, P., Dickler, M.N., Shah, P.D. et al. Alterations in PTEN and ESR1 promote clinical resistance to alpelisib plus aromatase inhibitors. Nat Cancer (2020). https://doi.org/10.1038/s43018-020-0047-1
  2. Kingston B, Bye H, Hubank M, et al. The genomic landscape of breast cancer based on ctDNA analysis: data from the plasmaMATCH trial. Presented at: 2019 San Antonio Breast Cancer Symposium; December 10-14; San Antonio, TX. Abstract GS3-07

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Source: Guardant Health, Inc.

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