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Purpose: After progression to immunotherapy, the standard of care for non-small cell lung cancer (NSCLC) was limited. Administration of the same or different immune checkpoint inhibitors (i.e., ICI rechallenge) may serve as a novel option. The present study aimed to evaluate the efficacy of ICI rechallenge for NSCLC and explore prognostic factors. Methods: In this retrospective cohort study, data of advanced or metastatic NSCLC patients rechallenged with ICI at the Cancer Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College between December 2018 and June 2021 were retrieved. Progression-free, overall survivals (PFS; OS), etc. were calculated. Subgroup analyses were conducted according to baseline characteristics, prior treatment results, etc. for prognostic factor exploration using the Cox model. Results: Forty patients were included. Median age was 59 years. Thirty-one (78%) were male. Twenty-seven (68%) were smokers. Adenocarcinoma (28 [70%]) was the major histological subtype. Median PFS of patients receiving initial ICI was 5.7 months. The most common rechallenge regimens were ICI plus chemotherapy and/or angiogenesis inhibitor (93%). Seventeen (43%) were rechallenged with another ICI. Median PFS for ICI rechallenge was 6.8 months (95% CI 5.8–7.8). OS was immature. Tendencies for longer PFS were observed in nonsmoker or patients with adenocarcinoma, response of stable/progressive disease in initial immunotherapy, or whose treatment lines prior to ICI rechallenge were one/two. However, all results of prognostic factors were nonsignificant. Conclusion: ICI rechallenge may be an option for NSCLC after progress to immunotherapy. Further studies to confirm the efficacy and investigate prognostic factors are warranted. [ABSTRACT FROM AUTHOR]

Objectives: To analyze the clinical relevance of heterogeneous phenotypes of peripheral circulating tumor cells (CTCs) in non-small cell lung cancer (NSCLC). Materials and Methods: CTCs in 5 mL venous blood were enriched using the Canpatrol™ CTC technique in 82 NSCLC patients. And then, CTCs were subjected to RNA in situ hybridization with a combination of epithelial (EpCAM and CK8/18/19) and mesenchymal (vimentin and TWIST1) markers. Results: According to the fluorescent dots, CTCs were classified into three groups, including epithelial CTCs (E-CTC), hybrid epithelial/mesenchymal phenotypes (E/M-CTCs) and mesenchymal CTCs (M-CTCs). In 82 NSCLC cohort, only 2 patients didn't detect CTCs, the overall CTCs detection rate was 97.5% (80/82). For 60 treatment naïve NSCLC, only one patient didn't detect CTCs. The median number of total CTCs, hybrid E/M phenotype CTCs, E-CTCs and M-CTCs per 5 mL blood was 22 (range 1–90), 13 (range 0–83), 1 (range 0–17 and 0–47), respectively. Hybrid E/M CTCs, especially the e = m-CTCs, significantly differed between patients with and without distant metastasis. M-CTCs in advanced NSCLC patients were significantly more than the numbers observed in early stage patients. Patients with pure hybrid E/M-CTCs showed a lower proportion in distant metastasis positive cohort compared to negative ones (7% vs 22%), while patients with E + E/M CTCs (20% vs 9%) and E/M + M CTCs (33% vs 20%) showed a higher proportion. CTCs dynamic changes after treatment in 12 advanced NSCLC patients suggested that hybrid E/M-CTCs were related to the primary tumor size at baseline, while M-CTCs may suggest the progression of NSCLC. Conclusion: We concluded that E-CTCs with a hybrid E/M phenotype are associated to metastasis in therapy-naïve NSCLC patients. [ABSTRACT FROM AUTHOR]

Purpose: Osimertinib, a third-generation epidermal growth factor receptor tyrosine-kinase inhibitor (EGFR-TKI), has demonstrated substantial clinical benefit in patients with non-small-cell lung cancer (NSCLC) who were resistant to early-generation EGFR-TKIs and had acquired a T790M mutation. The aim of our study was to identify the mechanisms underlying resistance to osimertinib and to correlate them with clinical outcomes. Methods: We retrospectively analyzed patients with advanced NSCLC who received osimertinib for T790M-mutated acquired resistance to prior EGFR-TKIs between March 1, 2017 and December 31, 2018. Patients with paired molecular data of pre-osimertinib and after resistance development, which were not confirmed with small-cell lung cancer (SCLC) transformation, were included in the molecular analysis set. Results: Of 49 patients evaluated in the molecular analysis set, 24 patients maintained T790M mutation, while 25 patients exhibited T790M-loss. Molecular modifications were identified in 27 of 49 patients including EGFR acquired mutations (C797S, C796S, G796S, V802I, V834L, E758D and G724S), non-EGFR-dependent mutations (PIK3CA, ALK, BRAF, KRAS and TP53), EGFR amplification and MET amplification. At data cutoff, median progression-free survival (PFS) was 9.3 months in the T790M-retain group compared with 7.8 months in T790M-loss patients (P = 0.053). Median PFS was significantly longer in patients with EGFR-dependent resistance mechanism (13.5 months) than in those with alternative pathway activation (8.2 months; P = 0.012). Conclusions: The study revealed heterogeneous mechanisms of resistance to osimertinib in advanced NSCLC patients and their association with clinical outcomes. Patients who maintained T790M mutation or with EGFR-dependent resistance mechanism had longer clinical outcome benefits. [ABSTRACT FROM AUTHOR]