PURPOSE: Standard treatment for cases of non-small cell lung cancer (NSCLC) exhibiting acquired drug resistance includes tumor rebiopsy, epidermal growth factor receptor (EGFR) mutation testing (e.g., for T790M mutations), and the subsequent administration of third-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs). However, rebiopsies are typically invasive, costly, and occasionally not feasible. Therefore, the present study aimed to assess rebiopsy procedures by analyzing real-world data collected by the ASTRIS study of patients with resistant NSCLC. MATERIALS AND METHODS: The present study used statistical models to evaluate data collected by the ASTRIS trial (NCT02474355) conducted at Yonsei Cancer Center, including the rebiopsy success rate, incidence of T790M mutations in collected tissue and plasma samples, and association of administered osimertinib treatment efficacy. RESULTS: In a total of 188 screened patients, 112 underwent rebiopsy. An adequate tumor specimen was obtained in 95 of these patients, the greatest majority of whom (43.8%) were subjected to bronchoscopy. T790M mutations were detected in 53.3% of successfully EGFR-tested rebiopsy samples. A total of 88 patients received osimertinib treatment, and the objective response rate and median progression-free survival time was 44.3% and 32.7 weeks, respectively, among the treated patients overall, but 57.8% and 45.0 weeks, and 35.2% and 20.4 weeks among patients who exhibited T790M-positive tissue (n=45) and plasma (n=54) samples, respectively. CONCLUSION: Approximately 60% of patients in the analyzed real-world cohort were eligible for tissue rebiopsy upon NSCLC progression. Osimertinib activity was higher in patients in whom T790M mutations were detected in tissues rather than in plasma samples.
Bronchoscopy ; Carcinoma, Non-Small-Cell Lung ; Cohort Studies ; Disease-Free Survival ; Drug Resistance ; Humans ; Incidence ; Models, Statistical ; Phosphotransferases ; Plasma ; Receptor, Epidermal Growth Factor ; Treatment Outcome

Purpose: This study was conducted to investigate the clinical characteristics of patients with advanced non–small cell lung cancer (NSCLC) harboring human epidermal growth factor receptor 2 (HER2) mutations and to evaluate response to standard treatment and HER2-targeted agents. Materials and Methods: Using tissue and/or blood next-generation sequencing, we identified 44 patients with NSCLC harboring HER2 mutations who were treated at Severance Hospital between December 2016 and February 2021. Clinical data, including patient characteristics, mutation status, incidence of metastasis for distant lesions, and response to chemotherapy, were retrospectively analyzed. Results: The median age was 58 years, and 61% of the patients were female. Most patients (64%) were never-smokers. Adenocarcinoma was the most predominant subtype (98%). A total of 66% of the patients had extrathoracic metastatic lesions, and 32% had intracranial lesions at initial presentation. The median time to the development of brain metastasis was 15.6 months (range, 2.4 to 43.7). The most common type of HER2 mutation was 12 base pair in-frame insertion in exon 20, A775_G776insYVMA. Of the 44 patients, two had concomitant driver mutations, one with epidermal growth factor receptor (EGFR) mutation (V769M), and one with BRAF mutation (V600E). Patients treated with pemetrexed-based chemotherapy (75%) had an overall response rate (ORR) and progression-free survival (PFS) of 30% and 8.3 months (95% confidence interval [CI], 3.9 to 12.7), respectively. The ORR and PFS of HER2-targeted agent treated patients (14%) were 0.0% and 1.9 months (95% CI, 0.1 to 2.8), respectively. Conclusion Given its distinct characteristics and treatment responses, novel treatment strategies for HER2-mutant NSCLC should be developed promptly to improve survival outcomes of patients.

Purpose: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have greatly improved survival in EGFR-mutant (EGFRm) non–small cell lung cancer (NSCLC); however, their effects on the tumor microenvironment (TME) are unknown. We assessed the changes induced by neoadjuvant erlotinib therapy (NE) in the TME of operable EGFRm NSCLC. Materials and Methods: This was a single-arm phase II trial for neoadjuvant/adjuvant erlotinib therapy in patients with stage II/IIIA EGFRm NSCLC (EGFR exon 19 deletion or L858R mutations). Patients received up to 2 cycles of NE (150 mg/day) for 4 weeks, followed by surgery and adjuvant erlotinib or vinorelbine plus cisplatin therapy depending on observed NE response. TME changes were assessed based on gene expression analysis and mutation profiling. Results: A total of 26 patients were enrolled; the median age was 61, 69% were female, 88% were stage IIIA, and 62% had L858R mutation. Among 25 patients who received NE, the objective response rate was 72% (95% confidence interval [CI], 52.4 to 85.7). The median disease-free and overall survival (OS) were 17.9 (95% CI, 10.5 to 25.4) and 84.7 months (95% CI, 49.7 to 119.8), respectively. Gene set enrichment analysis in resected tissues revealed upregulation of interleukin, complement, cytokine, transforming growth factor β, and hedgehog pathways. Patients with upregulated pathogen defense, interleukins, and T-cell function pathways at baseline exhibited partial response to NE and longer OS. Patients with upregulated cell cycle pathways at baseline exhibited stable/progressive disease after NE and shorter OS. Conclusion NE modulated the TME in EGFRm NSCLC. Upregulation of immune-related pathways was associated with better outcomes.