Early Assessment of Lung Cancer Immunotherapy Response via Circulating Tumor DNA

作者：Sarah B. Goldberg, Azeet Narayan, Adam J. Kole, Roy H. Decker, Jimmitti Teysir, Nicholas John Carriero, Angela Y. Lee, Roxanne Nemati, Sameer Kumar Nath, Shrikant Mane, Yanhong Deng, Nitin Sukumar, Daniel A. Zelterman, Daniel J. Boffa, Katerina A. Politi, Scott N. Gettinger, Lynn D. Wilson, Roy S. Herbst, Abhijit A. Patel · 发表于：Clinical Cancer Research · 年份：2018 · DOI：10.1158/1078-0432.ccr-17-1341 · 被引用次数：460 · 研究领域：Cancer Genomics and Diagnostics、Cancer Immunotherapy and Biomarkers、Lung Cancer Treatments and Mutations

Abstract Purpose: Decisions to continue or suspend therapy with immune checkpoint inhibitors are commonly guided by tumor dynamics seen on serial imaging. However, immunotherapy responses are uniquely challenging to interpret because tumors often shrink slowly or can appear transiently enlarged due to inflammation. We hypothesized that monitoring tumor cell death in real time by quantifying changes in circulating tumor DNA (ctDNA) levels could enable early assessment of immunotherapy efficacy. Experimental Design: We compared longitudinal changes in ctDNA levels with changes in radiographic tumor size and with survival outcomes in 28 patients with metastatic non–small cell lung cancer (NSCLC) receiving immune checkpoint inhibitor therapy. CtDNA was quantified by determining the allele fraction of cancer-associated somatic mutations in plasma using a multigene next-generation sequencing assay. We defined a ctDNA response as a >50% decrease in mutant allele fraction from baseline, with a second confirmatory measurement. Results: Strong agreement was observed between ctDNA response and radiographic response (Cohen's kappa, 0.753). Median time to initial response among patients who achieved responses in both categories was 24.5 days by ctDNA versus 72.5 days by imaging. Time on treatment was significantly longer for ctDNA responders versus nonresponders (median, 205.5 vs. 69 days; P < 0.001). A ctDNA response was associated with superior progression-free survival [hazard ratio (H...