87P - Application of tissue and liquid-based next generation sequencing (NGS) for comprehensive genomic profiling: Evaluating the clinical value of ctDNA technology in treatment decision making

Background

ctDNA is an attractive option to detect genomic aberrations in cancer. There is limited information on the decision-making value of ctDNA characterization compared to tissue-based testing. This ongoing study evaluated tissue based +/- liquid NGS testing, concordance/discordance between testing methods and the impact on therapeutic selection. NCT05057234.

Methods

Patients diagnosed with treatment naïve incurable, advanced-stage colorectal, melanoma, NSCLC, ovarian, triple negative breast, or prostrate cancer were eligible. Patients were randomized to cohort A tissue based NGS panel versus cohort B tissue based NGS panel + FoundationOne liquid CDx (F1LCDx). The clinical impact of Tier 1 alterations was classified as a genomics informed decision if the patient received targeted therapy or systemic selection by mutation status for up to 3 lines of treatment after testing results became available.

Results

From June 2021 to December 2023, 224 patients were randomized: Cohort A 121 and Cohort B 103 (9 patients were excluded from analysis as they did not complete F1LCDx). Tier 1 variants were noted in 48% cohort A and 56% cohort B (p=0.22). In cohort B the concordance of Tier 1 tissue and liquid NGS was 75% (31% variants/44% no variants), tissue only 15% and ctDNA only 10%. Table: 87P

Conclusions

In treatment naïve incurable, advanced-stage cancer, identification of Tier 1 variants was comparable with tissue versus tissue+liquid biopsy. The addition of F1LCDx to tissue testing was complementary, with 75% concordance and identification of 10% liquid-exclusive Tier 1 variants.

Clinical trial identification

NCT05057234 June 15, 2021.

Editorial acknowledgement

Legal entity responsible for the study

BC Cancer.

Funding

Roche Pharma AG.

Disclosure

P. Demarco: Financial Interests, Personal, Full or part-time Employment: Roche. D. Weymann: Financial Interests, Personal, Member of Board of Directors: Imprint Research Consulting; Financial Interests, Personal, Advisory Role: Roche Canada, AstraZeneca, Birota Economics Group. Y. Wang: Financial Interests, Personal, Advisory Board: BMS, AstraZeneca, Merck, Takeda; Financial Interests, Institutional, Research Grant: AstraZeneca. J. Laskin: Financial Interests, Personal, Advisory Board, invited speaker: Roche Canada; Financial Interests, Personal, Invited Speaker, speaker at educational event: Pfizer; Financial Interests, Personal, Advisory Board, invited to national ad board: Takeda; Financial Interests, Institutional, Research Grant, Funding for a IIT: Roche Canada. D. Regier: Financial Interests, Institutional, Research Funding: Roche. H. Lim: Financial Interests, Personal, Advisory Board, Honoria: BMS; Financial Interests, Personal, Advisory Board: Decipehera, Astellas, BeiGene, Taiho, Eisai, Amgen, Pfizer, CADTH, Merck, AstraZeneca, Roche; Financial Interests, Personal, Other, Beta-tester for system: Varian; Financial Interests, Institutional, Research Grant: Roche. S. Chia: Financial Interests, Personal, Advisory Board: Novartis, Hoffmann-LaRoche, Eli Lilly, AstraZeneca, Gilead, Merck, Daiichi Sankyo, Pfizer; Financial Interests, Institutional, Research Grant: Hoffmann-LaRoche. S. Yip: Financial Interests, Personal, Advisory Board: Amgen, AstraZeneca, Bayer, EMD Serono, Novartis, Pfizer, Roche; Financial Interests, Institutional, Research Grant: Roche. C. Ho: Financial Interests, Personal, Advisory Board: Amgen, AstraZeneca, Bayer, BMS, Eisai, EMD Serono, Janssen, Merck, Novartis, Pfizer, Roche, Jazz, Sanofi; Financial Interests, Institutional, Research Grant: AstraZeneca, Roche; Non-Financial Interests, Principal Investigator: Roche, AstraZeneca. All other authors have declared no conflicts of interest.