Clinical characteristics and treatment outcomes of 65 patients with BRAF-mutated non-small cell lung cancer (NSCLC).

e21745 Background: BRAF mutations are infrequently seen in non-small cell lung cancer (NSCLC) in Chinese population. We aimed to investigate the clinicopathologic characteristics and treatment outcomes of Chinese patients with NSCLC harboring BRAF mutations. Methods: We conducted a retrospective multicenter study in China of patients with NSCLC harboring BRAF mutations between Jan 2017 and Jul 2019. Results: A total of 65 patients treated in 22 centers were included, 54 harbored BRAF-V600E mutation and 11 had non-V600E mutations, including K601E, G469S, G469V, G469A, G596R, G466R and T599dup. No significant difference in age or gender was found between BRAF-V600E and non-V600E cases, while the majority of patients with non-V600E mutations were smokers (81.8%). Of the 18 patients with early-stage disease at diagnosis and underwent a resection, the median disease-free survival (DFS) was 43.2 months, 18.7 months and 10.1 months of stage I, II and IIIA patients (P = 0.07), respectively. In 46 patients with advanced-stage disease at data cutoff, disease control rate (DCR) and progression-free survival (PFS) of first-line anti-BRAF targeted therapy was superior than chemotherapy in patients harboring BRAF-V600E mutation (DCR, 100.0% vs. 70.0%, P = 0.027; median PFS, 9.8 months vs. 5.4 months, P = 0.149). Of 30 V600E-mutated patients who received anti-BRAF therapy during the course of disease, the median PFS of vemurafenib, dabrafenib, and dabrafenib plus trametinib was 7.8 months, 5.8 months and 6.0 months, respectively (P = 0.970). Median PFS were similar between V600E and non-V600E patients (5.4 months vs. 5.4 months, P = 0.825) to first-line chemotherapy. Nine patients were treated with checkpoint inhibitors, DCR and median PFS were 62.5% and 3.0 months (95%CI 2.9, 3.1), respectively. Conclusions: Our data demonstrated the clinical benefit of anti-BRAF targeted therapy in Chinese NSCLC patients harboring BRAF-V600E mutation. The value of immunotherapy and treatment selection among non-V600E population needs further study.[Table: see text]