Cancer Research, Statistics, and Treatment (Jan 2019)

Quality-adjusted time without symptoms or toxicity (Q-TWiST) analysis of a Phase III randomized trial to compare the benefit of gefitinib versus pemetrexed/carboplatin for epidermal growth factor receptor-mutated non-small cell lung cancer

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

DOI
https://doi.org/10.4103/CRST.CRST_17_19
Journal volume & issue
Vol. 2, no. 1
pp. 21 – 27

Abstract

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Background:> In an open-label, Phase III randomized study, gefitinib was found to be superior to pemetrexed-platinum in terms of progression-free survival in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer. In this analysis, we have assessed the efficacy of gefitinib over pemetrexed-platinum using quality-adjusted time without symptoms or toxicity (Q-TWiST) of treatment analysis method. Methods: The overall survival in each arm was partitioned into the following three health states: time spent in Grade 2 or above toxicity after randomization and before progression (TOX state), time spent after randomization and before progression without Grade 2 or above toxicity (TWiST state), and time spent after progression (REL state). The mean Q-TWiST was calculated for each arm using utility coefficients of 0.65 for TOX, 0.71 for TWiST, and 0.67 for REL states. The difference in Q-TWiST and the 95% confidence interval (CI) of the difference were calculated using a nonparametric bootstrap.P= 0.05 was considered statistically significant. Results: The mean TOX duration (37.6 vs. 16.2 days,P < 0.001) and TWiST duration (211.7 vs. 162.2 days, P = 0.002) were higher in the gefitinib arm. The mean REL state duration was higher in the pemetrexed-carboplatin arm (164.4 vs. 74.3 days,P < 0.001). The mean Q-TWiST was 224.6 days in the gefitinib arm versus 235.9 days in the pemetrexed-carboplatin arm. The difference was 11.3 days; 95% CI, 6.920–29.564,P= 0.224. Conclusion: The mean Q-TWiST of patients in the gefitinib arm was similar to that of patients in the pemetrexed-carboplatin arm. These results challenge the superiority of sequencing gefitinib followed by chemotherapy over pemetrexed-carboplatin followed by gefitinib in terms of Q-TWiST.

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