Motohiro Tamiya1, Kei Fujikawa2, Hidekazu Suzuki3, Toshihide Yokoyama4, Takeshi Uenami5, Akihiro Tamiya6, Yuki Sato7, Go Saito8, Junji Uchida9, Mitsunori Morita9, Tomonori Hirashima3, Yasushi Fukuda4, Masaki Kanazu5, Kazutaka Hosoya7, Takuji Suzuki8, Kiyonobu Ueno9, Daichi Fujimoto7, Toru Kumagai10, Satoshi Teramukai2. 1. Department of Thoracic Oncology, Osaka International Center Institute, Osaka, Japan. moto19781205@yahoo.co.jp. 2. Department of Biostatistics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. 3. Department of Thoracic Malignancy, Osaka Habikino Medical Center, Osaka, Japan. 4. Department of Respiratory Medicine, Kurashiki Central Hospital, Okiyama, Japan. 5. Department of Thoracic Oncology, National Hospital Organization Osaka Toneyama Medical Center, Osaka, Japan. 6. Department of Internal Medicine, National Hospital Organization Kinki-Chuo Chest Medical Center, Osaka, Japan. 7. Department of Respiratory Medicine, Kobe City Medical Center General Hospital, Hyogo, Japan. 8. Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan. 9. Department of Respiratory Medicine, Osaka General Medical Center, Osaka, Japan. 10. Department of Thoracic Oncology, Osaka International Center Institute, Osaka, Japan.
Abstract
BACKGROUND AND OBJECTIVE: Osimertinib as first-line treatment for patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor (EGFR) mutations remains controversial. Sequential EGFR-tyrosine kinase inhibitor (TKI) might be superior to the first line osimertinib in patients at risk of developing acquired T790M mutations. METHODS: We enrolled consecutive patients with EGFR-mutated (deletion 19 or L858R) advanced NSCLC treated with first-line drugs and evaluated predictive markers using classification and regression tree (CART) for the detection of T790M mutations based on patient backgrounds prior to initial treatment. RESULTS: Patients without acquired T790M mutations had worse outcomes than those with T790M mutations (median OS: 798 days vs. not reached; HR: 2.70; P < 0.001). CART identified three distinct groups based on variables associated with acquired T790M mutations (age, CYF, WBC, liver metastasis, and LDH; AUROC: 0.77). Based on certain variables, CART identified three distinct groups in deletion 19 (albumin, LDH, bone metastasis, pleural effusion, and WBC; AUROC: 0.81) and two distinct groups in L858R (age, CEA, and ALP; AUROC: 0.80). The T790M detection frequencies after TKI resistance of afatinib and first-generation EGFR-TKIs were similar (35.3% vs. 37.4%, P = 0.933). Afatinib demonstrated longer PFS (398 vs. 279 days; HR: 0.67; P = 0.004) and OS (1053 vs. 956 days; HR: 0.68; P = 0.051) than first-generation EGFR-TKIs. CONCLUSION: Identification of patients at risk of acquiring T790M mutations after EGFR-TKI failure may aid in choice of first-line EGFR-TKI. Furthermore, afatinib may be the more effective 1st-line EGFR-TKI treatment for patients at risk of developing T790M as initial EGFR-TKI resistance.
BACKGROUND AND OBJECTIVE: Osimertinib as first-line treatment for patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor (EGFR) mutations remains controversial. Sequential EGFR-tyrosine kinase inhibitor (TKI) might be superior to the first line osimertinib in patients at risk of developing acquired T790M mutations. METHODS: We enrolled consecutive patients with EGFR-mutated (deletion 19 or L858R) advanced NSCLC treated with first-line drugs and evaluated predictive markers using classification and regression tree (CART) for the detection of T790M mutations based on patient backgrounds prior to initial treatment. RESULTS: Patients without acquired T790M mutations had worse outcomes than those with T790M mutations (median OS: 798 days vs. not reached; HR: 2.70; P < 0.001). CART identified three distinct groups based on variables associated with acquired T790M mutations (age, CYF, WBC, liver metastasis, and LDH; AUROC: 0.77). Based on certain variables, CART identified three distinct groups in deletion 19 (albumin, LDH, bone metastasis, pleural effusion, and WBC; AUROC: 0.81) and two distinct groups in L858R (age, CEA, and ALP; AUROC: 0.80). The T790M detection frequencies after TKI resistance of afatinib and first-generation EGFR-TKIs were similar (35.3% vs. 37.4%, P = 0.933). Afatinib demonstrated longer PFS (398 vs. 279 days; HR: 0.67; P = 0.004) and OS (1053 vs. 956 days; HR: 0.68; P = 0.051) than first-generation EGFR-TKIs. CONCLUSION: Identification of patients at risk of acquiring T790M mutations after EGFR-TKI failure may aid in choice of first-line EGFR-TKI. Furthermore, afatinib may be the more effective 1st-line EGFR-TKI treatment for patients at risk of developing T790M as initial EGFR-TKI resistance.