Lung India (Jan 2018)

Efficacy of gefitinib in epidermal growth factor receptor-activating mutation-positive nonsmall cell lung cancer: Does exon 19 deletion differ from exon 21 mutation?

  • Amit Joshi,
  • Vijay Patil,
  • Vanita Noronha,
  • Anuradha Chougule,
  • Atanu Bhattacharjee,
  • Rajiv Kumar,
  • Supriya Goud,
  • Sucheta More,
  • Anant Ramaswamy,
  • Ashay Karpe,
  • Nikhil Pande,
  • Arun Chandrasekharan,
  • Alok Goel,
  • Vikas Talreja,
  • Abhishek Mahajan,
  • Amit Janu,
  • Nilendu Purandare,
  • Kumar Prabhash

DOI
https://doi.org/10.4103/lungindia.lungindia_201_17
Journal volume & issue
Vol. 35, no. 1
pp. 27 – 30

Abstract

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Background: This study was designed to evaluate the differential effect of epidermal growth factor receptor (EGFR) mutation status (exon 19 vs. 21) on progression-free survival (PFS) and overall survival (OS) in treatment-naïve advanced EGFR mutation-positive nonsmall cell lung cancer (NSCLC) treated with gefitinib as first-line agent. Methods: This was a post hoc analysis of EGFR-mutated (exon 19 and 21) advanced-stage (Stage IIIB or IV), chemotherapy-naive NSCLC patients treated with gefitinib as first line in a phase 3 randomized study. Patients were treated with gefitinib 250 mg daily. Patients underwent axial imaging for response assessment on D42, D84, D126, and subsequently every 2 months till progression. Responding or stable patients were treated until progression or unacceptable toxicity. SPSS was used for statistical analysis. Kaplan–Meier method was used for survival estimation and log-rank test for comparison. Cox proportion hazard model was used for multivariate analysis. Results: One hundred and forty-one patients were eligible for analysis, of which 78 were males and 63 were females. A total of 127 patients (90.1%) were ECOG 0–1 while 14 patients (9.1%) were ECOG >1. Exon 21 mutation was present in 65 patients (46.1%) and exon 19 mutation in 76 patients (53.9%). One hundred and thirty-three of 141 patients were evaluable for response. Response rate of patients having exon 19 mutation was 72.9% (51 patients, n = 70) while it was 55.6% in patients having exon 21 mutation (35 patients, n = 63) (P = 0.046). Median PFS in exon 19-mutated patients was 9.3 months (95% confidence interval [CI] 6.832–11.768) compared to 7.8 months (95% CI 5.543–10.0) (P = 0.699) in exon 21-mutated patients. The median OS in exon 19-mutated patients was 19.8 months (95% CI 16.8–22.7), and it was 16.5 months (95% CI 10.9–22.1) in exon 21-mutated patients (P = 0.215). Conclusion: There were no differential outcomes in the Indian patients of advanced-stage NSCLC with exon 19 and 21 EGFR mutations treated with gefitinib.

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