Totality outcome of afatinib sequential treatment in patients with EGFR mutation-positive non-small cell lung cancer in South Korea (TOAST): Korean Cancer Study Group (KCSG) LU-19-22
Hyun Ae Jung, Min Hee Hong, Hyun Woo Lee, Kyung Hee Lee, Il Hwan Kim, Young Joo Min, Hee Kyung Ahn, Byoung Yong Shim, Yoon Hee Choi, Yun‐Gyoo Lee, Jeong‐Ah Kim, Joung Soon Jang, Seong Hoon Shin, Keon Uk Park, Jin Hyoung Kang, Keunchil Park
Abstract
Background: Irrespective of the first-line epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor chosen, acquired resistance to therapy is inevitable. Therefore, a key consideration when assessing therapeutic choices is the availability of subsequent treatment options following disease progression. We assessed clinical outcomes in patients who received first-line afatinib treatment with various second-line treatments including osimertinib for patients acquiring the T790M mutation. Methods: mutation-positive (EGFR M+) non-small cell lung cancer (NSCLC) patients receiving first-line afatinib treatment were categorized by second-line treatment: T790M+ sequentially treated with osimertinib (cohort A, n=116); T790M- given chemotherapy or others (cohort B, n=143); patients with unknown T790M status (cohort C, n=111); and patients who were undergoing afatinib treatment at the time of data collection, were dead, had discontinued afatinib treatment due to serious adverse events or were lost to follow-up (cohort D, n=367). The primary outcomes were total time on treatment (TOT) and TOT for first-line (TOT-1) and second-line treatments (TOT-2). Secondary outcomes were objective response rates (ORR), overall survival (OS), and central nervous system (CNS) efficacy. Results: Median total TOT in cohorts A, B, C, and D were 35.10 months [95% confidence interval (CI): 30.09-43.53 months], 18.80 months (95% CI: 16.92-20.20 months), 12.00 months (95% CI: 10.22-14.98 months), and 42.60 months (95% CI: 30.95-59.23 months), respectively. The ORR of patients given afatinib was 75.7%. In patients with initial brain metastasis without local treatment, the CNS response rate was 67.0% and CNS progression-free survival was 24.70 months (95% CI: 19.84-33.15 months). Conclusions: M+ NSCLC patients.