Plasma EGFR mutation ctDNA dynamics in patients with advanced EGFR-mutated NSCLC treated with Icotinib: phase 2 multicenter trial result.

Plasma epidermal growth factor receptor mutation (EGFRm) circulating tumor DNA (ctDNA) dynamics exhibit promise in predicting outcomes in patients with EGFRm-advanced non-small cell lung cancer (NSCLC). However, there remains limited trial-level data on integrating ctDNA monitoring into clinical practice. We performed a prospective, multicenter trial to investigate the relationship between EGFRm ctDNA dynamic changes and clinical outcomes in NSCLC patients with EGFRm. Ninety-eight treatment-naive EGFRm-advanced NSCLC patients were recruited and administered icotinib until disease progression. Plasma samples were collected at baseline and four weeks after icotinib administration. ctDNA was analyzed using a droplet-digital polymerase chain reaction. At baseline, 71.4% of patients had detectable EGFRm ctDNA. Among them, 45.9% of patients' ctDNA became undetectable within four weeks of treatment. These patients demonstrated significantly longer progression-free survival (PFS) and overall survival (OS) than those with detectable ctDNA after treatment (P = 0.004 and < 0.001, respectively) and were comparable to those with undetectable ctDNA at both baseline and four weeks. ctDNA detectable at four weeks emerged as a poor independent risk factor for PFS and OS. Patients whose ctDNA became undetectable after treatment had outcomes similar to those with initially undetectable ctDNA, underscoring the predictive value of ctDNA dynamics in treatment efficacy.Registry and the Registration No. of the study/trial: ChiCTR-DDD-17013131. Date of registration: 2017-10-27.