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2019 ASCO Annual Meeting!

Session: Developmental Therapeutics and Tumor Biology (Nonimmuno)

Type: Poster Session

Time: Saturday June 1, 8:00 AM to 11:00 AM

Location: Hall A

Analytical validation of a tumor-agnostic integrated multianalyte circulating tumor DNA (ctDNA) assay in early-stage cancer.

Circulating Biomarkers

Developmental Therapeutics and Tumor Biology (Nonimmuno)

2019 ASCO Annual Meeting

Abstract No:

Poster Board Number:
Poster Session (Board #49)

J Clin Oncol 37, 2019 (suppl; abstr 3057)

Author(s): Anna Hartwig, Carlo Artieri, Ariel Jaimovich, Emily E. Van Seventer, Aparna Raj Parikh, Ryan Bruce Corcoran, Arthur Baca, AmirAli Talasaz; Guardant Health, Inc., Redwood City, CA; Massachusetts General Hospital, Boston, MA; Guardant Health, Inc, Redwood City, CA

Abstract Disclosures


Background: ctDNA sequencing has been rapidly adopted for the identification of targetable somatic alterations (alts) in patients with advanced cancers. However, early stage disease detection has been hindered by low levels of ctDNA in circulation and the presence of confounding non-tumor-related somatic alts. We developed and validated a ctDNA assay that combines somatic and epigenomic signals to detect early stage tumors without tumor tissue or white blood cells (WBC). Methods: Using a single input sample, our assay integrates the sensitive detection of genomic alts with quantification of epigenomic signals associated with cancer. Non-tumor alts (e.g., clonal hematopoiesis of indeterminate potential; CHIP) are excluded using a newly developed bioinformatic classifier. To assess analytical sensitivity, specificity, and positive and negative reproducibility, we tested 337 clinical and contrived samples. Results: Clinical specificity was determined using 80 plasma samples from 50-75 year old presumptive cancer-free donors, and resulted in a single false positive (99% specificity). Analytical sensitivity (limit of detection) was established using a dilution series of 4 different late stage CRC pts tested in triplicate at a clinically relevant DNA input (30 ng) across multiple batches. 100% sensitivity was maintained even at the lowest tested level (estimated 0.1% tumor level). Positive/negative reproducibility was assessed by testing triplicates of diluted late stage samples and age-matched healthy donors, respectively, across different cfDNA inputs, and multiple reagent lots. Both positive and negative calls were 100% concordant across all replicates. Independent estimation of tumor levels from epigenomic or genomic signals produced highly concordant results (correlation r-value: 0.82, p-value: 3e-16). Conclusions: We designed and validated a highly specific ctDNA assay that integrates both genomic and epigenomic signals to allow for accurate and quantitative tumor level detection in early stages of the disease without requiring tumor tissue or WBC.

Other Abstracts in this Sub-Category:


1. Genome-wide cell-free DNA fragmentation profiling for early cancer detection.

Meeting: 2019 ASCO Annual Meeting Abstract No: 3018 First Author: Alessandro Leal
Category: Developmental Therapeutics and Tumor Biology (Nonimmuno) - Circulating Biomarkers


2. Multimodality liquid biopsy for early monitoring and outcome prediction in first-line metastatic HER2-negative breast cancer: Final results of the prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG)— COMET study.

Meeting: 2019 ASCO Annual Meeting Abstract No: 3019 First Author: Jean-Yves Pierga
Category: Developmental Therapeutics and Tumor Biology (Nonimmuno) - Circulating Biomarkers


3. Circulating androgen receptor (AR) gene amplification and resistance to 177Lu-PSMA-617 in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Results of a phase II clinical trial.

Meeting: 2019 ASCO Annual Meeting Abstract No: 3020 First Author: Ugo De Giorgi
Category: Developmental Therapeutics and Tumor Biology (Nonimmuno) - Circulating Biomarkers