Publication-only abstracts (abstract number preceded by an "e"), published in conjunction with the 2019 ASCO Annual Meeting but not presented at the Meeting, can be found online only.
Association of allele frequency of EGFR mutation with efficacy of EGFR TKIs in advanced non-small cell lung cancer.
Metastatic Non-Small Cell Lung Cancer
Lung Cancer—Non-Small Cell Metastatic
2019 ASCO Annual Meeting
J Clin Oncol 37, 2019 (suppl; abstr e20678)
Author(s): Xiang-Meng Li, Jin-Ji Yang, Yi-Long Wu; Guangdong Lung Cancer Institute, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China
Background: Next-generation sequencing (NGS) is beneficial to precision medicine. However, it remains elusive whether the epidermal growth factor receptor (EGFR) mutant allele frequency (MAF) tested by NGS is predictive for tyrosine kinase inhibitors (TKIs) therapy in advanced non-small-cell lung cancer (NSCLC). Methods: We enrolled 194 advanced NSCLC EGFR mutant patients receiving erlotinib or gefitinib orally. A total of 196 baseline tissue samples from a phase III clinical trial (CTONG 0901; clinicaltrials.gov No.NCT01024413) between July 2009 and 2014 were analyzed by a panel of 168 lung cancer-related genes NGS. The median EGFR MAF was 25.8% (range, 1.4%-86.2%). Patients were divided into MAF low group (1.4%-25.8%) and high group (25.8%-86.2%). We defined PFS as the time of randomization to confirmed disease progression or death from any cause. OS was calculated from randomization to the last visit or death from any cause. Tumor response was assessed by investigators according to RECIST version 1.1. Survival was estimated using the Kaplan-Meier method. The relationship between the response of TKIs and EGFR MAF were evaluated by Pearson Chi-square test or Fisher’s exact test. Results: The median age was 58.7 years (range,31.2- 85.1), 92 (47.4%) were male, 41(21.1%) were smokers,189 (97.4%) had adenocarcinoma, 105 (54.1%) patients were identified as carrying EGFR exon 19 deletion, while one patient with the co-existence of T790M mutation. 85 (43.8%) patients harbored EGFR exon 21 L858R mutation. After 5 weeks of treatment, the initial response was assessed. No significant difference was observed in initial response between the high and low groups (P = 0.502). The difference in best response to EGFR-TKIs between the groups was not significant (P = 0.557). Objective response rate (ORR) was 56.2% and 57.5% respectively. There was no significant difference in median PFS [11.2 (95% CI,10.0 -12.3) vs 12.4 (95% CI,10.3-14.5) months, P = 0.509] between the groups. The high group was not significantly superior to the low group in median OS[20.5 (95% CI,18.0-23.0) vs 23.1 (95% CI,19.3-27.0) months, P = 0.500]. Conclusions:EGFR mutant allele frequency tested by NGS is not associated with the efficacy of EGFR TKIs in advanced NSCLC.