Abstract 2195: Real-world experience with afatinib as first-line treatment in advanced non-small cell lung cancer in a university hospital

Abstract

Abstract Purpose: In patients with non-small cell lung cancer (NSCLC), mutations in the epidermal growth factor receptor (EGFR) have been associated with sensitivity to EFGR-Tyrosin Kinase Inhibitors (TKIs). The aim of this study was to analyze clinical efficacies of first line afatinib treatment. Experimental Design: We collected patients with EGFR mutation positive NSCLC who started first-line afatinib treatment between Jan 2015 and Sep 2017. We reviewed clinical characteristics of the patients, laboratory finding, tumor response rate, side effects, progression free survival (PFS), 2nd biopsy result, and overall survival (OS), retrospectively. Results: Forty six patients were available for analysis among all 62 patients (1st to 8th line chemotherapy). At the time of data analysis in October 2018, nine patients were still on afatinib. Median age was 67.4 years-old. 20 (44%) patient had EGFR 19 deletion, 25 (54%) EGFR L858R mutation, 1 (2%) S768I. 10 patients (21.7%) had brain metastasis at baseline study. Tumor response was 58.7% with partial response, no change 19.6%, progressive disease 2%, and non-evaluable 19.6%. Mean follow-up time was 21.6 months (13.5 to 42.5 month) from start of afatinib treatment. Twenty-eight progression or death events were observed. Median PFS was 13.5 months (95% CI: 10.5 to 16.5 months). There were no differences in smoking, gender, EGFR types. 37 patients (80.4%) had dose reduction from initial dose. 6 patients (13.1%) discontinued due to afatinib toxicity. 6 patients (13%) had G3 toxicity, but usually manageable by dose reduction or supportive care. 1 case of doxycycline induced pneumonitis occurred. The PFS of dose reduction group due to adverse events was longer than standard group (14.9 months vs 10.1 months, p=0.023). In dose reduction group, body weight was low (53.1 kg vs 68.4 kg, p=0.002), the ratio of never smoker (87.9% vs 37.5%, p=0.001) and female (87.4% vs 47.4%, p=0.048) were higher than standard group. After progression, 2nd biopsy was done in 17 patients. T790M mutation was detected in 8 patients, so detection rate was 47.1%. 6 patients received oximertinib treatment. Median OS was 38.6 months. Conclusions: Afatinib is one of appropriate first-line treatment option for patients with advanced EGFR positive NSCLC. The dose reduction due to adverse events was common in low-body weight female never smoking patients, but the PFS was increased. With use of new 3rd-gen EGFR TKIs in the first-line setting, optimal sequencing of EGFR TKIs needs to be validated in maximizes treatment outcomes. Citation Format: Taewon Jang, Jaehoon Kim. Real-world experience with afatinib as first-line treatment in advanced non-small cell lung cancer in a university hospital [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2195.