172P - Antacid and de novo brain metastases in EGFR-mutant NSCLC patients treated with first-line, first-generation EGFR-TKIs

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Cytotoxic agents
Non-small-cell lung cancer
Therapy
Biological therapy
Presenter Yu-Mu Chen
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors Y. Chen1, M. Lin2, C. Lai1, W. Fang1, H. Chang1, C. Wang1, C. Tseng1
  • 1Internal Medicine, Chang Gung Memorial Hospital-Kaohsiung, 833 - Kaohsiung/TW
  • 2Internal Medicine, Chang Gung Memorial Hospital-Kaohsiung, Kaohsiung/TW

Abstract

Background

Antacid treatments decrease the serum concentrations of first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs), although it is unknown whether antacids affect clinical outcomes. As cerebrospinal fluid concentrations of TKIs are much lower than serum concentrations, we hypothesized that this drug-drug interaction might affect the prognosis of patients with de novo brain metastases.

Methods

This retrospective study evaluated 269 patients with EGFR-mutant non-small cell lung cancer (NSCLC) who had been diagnosed between January 2011 and 2014, and had been treated using first-line first-generation EGFR-TKIs. Among these patients, we identified patients who concurrently used H2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) as antacids. Patients who exhibited >30% overlap between the use of TKIs and antacids were considered antacid users.

Results

Fifty-seven patients (57/269, 21.2%) were antacid users, and antacid use did not significantly affect progression-free survival (PFS; no antacids: 11.2 months, H2RAs: 9.4 months, PPIs: 6.7 months; p = 0.234). However, antacid use significantly reduced overall survival (OS; no antacids: 25.0 months, H2RAs: 15.5 months, PPIs: 11.3 months; p = 0.002). Antacid use did not affect PFS for various metastasis sites, although antacid users with de novo brain metastases exhibited significantly shorter OS, compared to non-users (11.8 vs. 16.3 months, respectively; p = 0.041). Antacid use did not significantly affect OS in patients with bone, liver, or pleural metastases.

Conclusions

Antacids usage shortened OS duration in EGFR-mutant, NSCLC patients treated with first-line, first-generation EGFR-TKIs, especially in patients with de novo brain metastasis.

Clinical trial identification

nil (retrospective trial)

Legal entity responsible for the study

N/A

Funding

N/A

Disclosure

All authors have declared no conflicts of interest.