Concordance of blood and tissue TMB from NGS testing in real-world settings and their ability to predict response to immunotherapy.

• DOI: 10.1200/jco.2021.39.15_suppl.2540
• Publication Date: 2021-06-02T13:57:27Z
• Authors: Emma Sturgill; Amanda Misch; Carissa Jones; Daniel Luckett; Xiaotong Fu; Suzanne Fields Jones; Howard A. Burris III; David R. Spigel; Andrew Jacob McKe...
• Keywords: Concordance

2540 Background: Tumor mutational burden (TMB) detected by tissue-based Next Generation Sequencing (NGS) is a biomarker for immunotherapy (IO) response. Plasma-based NGS vendors have developed methods quantifying TMB from circulating tumor DNA; however, the concordance of blood-TMB (bTMB) and tissue-TMB (tTMB) in real-world settings has not been examined. In this study, we analyzed paired bTMB-tTMB values cancer patients community oncology clinics who underwent both plasma- testing to determine whether bTMB predicts response IO equal tTMB. Methods: We 112 patient-matched pairs 102 unique received profiling at any point care. results were reported Foundation Medicine (n = 28 plasma, n 66 tissue), Guardant Health 78 plasma), Caris Life Sciences 42 tissue). linked with electronic medical records Genospace, Sarah Cannon’s precision medicine platform. Pearson’s correlation (r) Lin’s (ρ) coefficients used statistical analysis. Results: exceeded tTMB an average 2.4-fold; therefore, while two showed positive linear (r 2 0.62, p 0.01e-27) their was only moderate (ρ 0.58, 112). Gastrointestinal cancers exhibited lowest 0.01, 0.5) 0.03, 35). The discordance between outcome specimens being collected on different dates, as bTMB/tTMB ratio did correlate time plasma tissue specimen collection 0.003, 0.84, While majority had agreement high vs. low status (High ≥ 10 mut/Mb; Low < mut/Mb), considerable portion bTMB-High/tTMB-Low (see table). Strikingly, treatment failure (TTF) that surpassed bTMB-High/tTMB-High cohort Considering alone, outperformed those (bTMB-High: TTF 200 days, 21; bTMB-Low: 125 12). Conclusions: where tissue- plasma-based panels are ordered standard care, consistently higher than values. This discrepancy leads tests resulting TMB-High designation more frequently tests. Patients perform relatively well IO, indicating may be particularly effective sensitivity.[Table: see text]