Purpose: Tumor somatic mutation analysis is part of the standard management of metastatic lung cancer. However, physicians often have to deal with small biopsies and consequently with challenging mutation testing. Circulating free DNA (cfDNA) is a promising tool for accessing the tumor genome as a liquid biopsy. Here, we evaluated next-generation sequencing (NGS) on cfDNA samples obtained from a consecutive series of patients for the screening of a range of clinically relevant mutations.Experimental Design: A total of 107 plasma samples were collected from the BioCAST/IFCT-1002 lung cancer study (never-smokers cohort). Matched tumor DNA (tDNA) was obtained for 68 cases. Multiplex PCR-based assays were designed to target specific coding regions in EGFR, KRAS, BRAF, ERBB2, and PI3KCA genes, and amplicon sequencing was performed at deep coverage on the cfDNA/tDNA pairs using the NGS IonTorrent Personal Genome Machine Platform.Results: CfDNA concentration in plasma was significantly associated with both stage and number of metastatic sites. In tDNA, 50 mutations (36 EGFR, 5 ERBB2, 4 KRAS, 3 BRAF, and 2 PIK3CA) were identified, of which 26 were detected in cfDNA. Sensitivity of the test was 58% (95% confidence interval, 43%-71%) and the estimated specificity was 87% (62%-96%).Conclusion: These data demonstrate the feasibility and potential utility of mutation screening in cfDNA using IonTorrent NGS for the detection of a range of tumor biomarkers in patients with metastatic lung cancer. Clin Cancer Res; 20(17); 4613-24. Ó2014 AACR.
Immune checkpoint inhibitors, notably antibodies targeting programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1), have modified the management of patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC). Several PD-1/PD-L1 inhibitors have been approved by health authorities for this indication and others are in clinical development. However, only a subset of patients truly benefits from these agents. For patients with mutated EGFR or translocated ALK NSCLC, for whom an immune checkpoint inhibitor can be prescribed after progression on tyrosine kinase inhibitors and chemotherapy, information is scarce and sometimes contradictory. Phase III randomized clinical trials have evaluated different immune checkpoint inhibitors (nivolumab, pembrolizumab, atezolizumab) vs. chemotherapy as second- or subsequent-line therapy in NSCLC, but included very few patients with EGFR/ALK-positive disease. Subgroup analyses found that these patients did not benefit from immune checkpoint inhibitors. Retrospective data show progression-free survival lasting only 1.2-2.1 months. Preclinical data suggested a lower expression of PD-L1 in EGFR/ALK-positive patients compared to EGFR/ALK-negative patients. Our objective herein is to provide an up-to-date review of available data from the various publications on the impact of immune checkpoint inhibitors in patients with EGFR/ALK-positive NSCLC.
Statement of Interest: S. Rao has received educational grants from Novartis (UK) and GlaxoSmithKline (UK) for attending conferences and delivering lectures as part of an educational programme organised by the two companies.
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