Clinical potential of circulating free DNA and circulating tumour cells in patients with metastatic non‐small‐cell lung cancer treated with pembrolizumab

Abstract

Immune checkpoint inhibitors (ICIs), such as pembrolizumab, are revolutionizing therapeutic strategies for different cancer types, including non-small cell lung cancer (NSCLC). However, only a subset of patients benefits from this therapy, and new biomarkers are needed to select better candidates. In this study, we explored the value of liquid biopsy analyses, including circulating free DNA (cfDNA) and circulating tumour cells (CTCs), as a prognostic or predictive tool to guide pembrolizumab therapy. For this purpose, a total of 109 blood samples were collected from 50 patients with advanced NSCLC prior to treatment onset and at 6 and 12 weeks after the initiation of pembrolizumab. Plasma cfDNA was measured using hTERT quantitative PCR assay.The CTC levels at baseline were also analysed using two enrichment technologies (CellSearch ® and Parsortix systems) to evaluate the efficacy of both approaches at detecting the presence of programmed cell death ligand 1 (PD-L1) on CTCs. Notably, patients with high baseline hTERT cfDNA levels had significantly shorter progression-free survival (PFS) and overall survival (OS) than those with low baseline levels. Moreover, patients with unfavourable changes in the hTERT cfDNA levels from baseline to 12 weeks showed a higher risk of disease progression.Additionally, patients in whom CTCs were detected using the CellSearch ® system had significantly shorter PFS and OS than patients who had no CTCs. Finally, multivariate regression analyses confirmed the value of the combination of CTCs and cfDNA levels as an early independent predictor of disease progression, identifying a subgroup of patients who were negative for CTCs and presented low levels of cfDNA who particularly benefited from the treatment.

Neutrophil Extracellular Traps in Cancer Therapy Resistance

“…They showed that improved response to therapy correlated with lower nucleosome levels before the second and third cycle of chemotherapy, independent of other confounders [ 129 ]. Various other groups have in turn shown cfDNA levels predict limited response to chemotherapy and immunotherapy in various cancers [ 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 ]. This human data is notable since it suggests a pan-cancer clinical association between elevated cfDNA and limited therapeutic response.…”

Plasma cell-free DNA as a prognostic biomarker in small cell lung cancer patients

“…Thus, despite the few known driver mutations found in SCLC, cfDNA quantification allows to quantify the total levels before treatment and monitor the changes during therapy. Recently, our group demonstrated the feasibility to quantify cfDNA levels in non-small cell lung cancer patients and its association with patients’ outcomes (45), suggesting its possible utility in SCLC.…”

“…Therefore, both methods could be used to robustly measure the cfDNA content. However, to complete our study we chose the qPCR assay, which is a high sensitive and specific assay for cfDNA quantification in SCLC patients, and was previously employed in studies focused on non-small cell lung cancer (45–48).…”

“…2 µL of the sample were employed to quantify by the fluorometric instrument Qubit 4 using the Qubit dsDNA HS Assay Kit (ThermoFisher Scientific, Waltham, MA, USA). In the other hand, samples were quantified by a qPCR assay, described previously (29). Briefly, each qPCR reaction was carried out in a final volume of 20 µL: 10 µL of TaqMan Universal Mastermix (Thermo Fisher Scientific, Waltham, MA, USA), 1 µL of hTERT hydrolysis probe and 2 µL of the sample.…”

Liquid Biopsy for Monitoring EC Patients: Towards Personalized Treatment

“…Thus, CRC patients with positive postsurgery ctDNA levels have a higher risk to recur than those with undetectable levels [32,33]. In the same line, increments in ctDNA or CTCs levels have been associated with disease progression of metastatic lung and breast cancer patients, even before the confirmation of progression by radiological assessment [34][35][36][37]. Additionally, liquid biopsy assessment has a clear role for monitoring and characterizing the resistance to targeted therapies as many works have demonstrated in the last years in the context of hormone therapy in breast cancer patients and anti-EGFR strategies in mCRC or immunotherapy in NSCLC [38][39][40].…”