Importance: The inability to obtain a pathological diagnosis in a certain proportion of patients with clinically diagnosed advanced lung cancer impedes precision treatment in clinical practice.
Objective: To evaluate the clinical outcome of first-line icotinib in patients with clinically diagnosed advanced lung cancer with unknown pathological status and positive epidermal growth factor receptor (EGFR)-sensitizing variants assessed by circulating tumor DNA (ctDNA).
Design, setting, and participants: The Efficiency of Icotinib in Plasma ctDNA EGFR Mutation-Positive Patients Diagnosed With Lung Cancer (CHALLENGE) trial is a prospective, multicentered, open-label, single-arm phase 2 nonrandomized clinical trial conducted between July 1, 2017, and July 31, 2019. Patients with systemic treatment-naive, clinically diagnosed advanced peripheral lung cancer, unknown pathological status, and positive pretreatment plasma EGFR-sensitizing variants were eligible. A total of 391 potentially eligible Chinese patients from 19 centers in China were screened for ctDNA EGFR variants by 3 independent detection platforms (Super amplification refractory mutation system [SuperARMS] polymerase chain reaction, droplet digital polymerase chain reaction, and next-generation sequencing), and those with EGFR variants tested by any platform were included. Analyses were conducted from September 9 to December 31, 2021.
Interventions: Enrolled patients were treated with oral icotinib tablets (125 mg 3 times daily) until disease progression, death, or treatment discontinuation due to various reasons, such as toxic effects and withdrawing consent.
Main outcomes and measures: The primary end point was objective response rate (ORR). The secondary end points included progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and the concordance among the 3 detection platforms.
Results: Of 116 included patients, 76 (65.5%) were female, and the median (range) age was 64 (37-85) years. The median (IQR) follow-up duration was 36.3 (30.2-40.7) months. The ORR was 52.6% (95% CI, 43.1%-61.9%). The median PFS and OS were 10.3 months (95% CI, 8.3-12.2) and 23.2 months (95% CI, 17.7-28.0), respectively, and the DCR was 84.5% (95% CI, 76.6%-90.5%). The concordance rate among the 3 detection platforms was 80.1% (313 of 391), and the clinical outcomes in patients identified as positive by any platform were comparable.
Conclusions and relevance: This prospective phase 2 nonrandomized clinical trial suggests that for patients with clinically diagnosed advanced lung cancer with unknown pathological status, ctDNA-based EGFR genotyping could help decision-making in particular clinical situations, while still warranting future larger-scaled real-world exploration.
Trial registration: ClinicalTrials.gov Identifier: NCT03346811.