JMIR Publications

ABSTRACT

Introduction. Healthcare system-wide outcomes from routine treatment with erlotinib and gefitinib are incompletely understood. Objectives: To describe the effectiveness of erlotinib and gefitinib during the first decade of their routine use for treating advanced Epidermal Growth Factor Receptor (EGFR) mutation-positive non-squamous non-small-cell lung cancer (NSCLC) in the entire cohort of patients treated in Aotearoa New Zealand (NZ). Methods. Patients were identified and data collated from national pharmaceutical dispensing, cancer registration and mortality registration electronic databases by deterministic data linkage using National Health Index numbers. Time-to-treatment discontinuation and overall survival were measured from the date of first dispensing of erlotinib or gefitinib and analysed by Kaplan-Meier curves. Associations of treatment outcomes with baseline factors were evaluated using univariable and multivariable Cox regressions. Results. Overall, 752 patients were included who started treatment with erlotinib (n=418) or gefitinib (n=334) before Oct 2020. Median time-to-treatment discontinuation was 11.6 months (95%CI 10.8-12.4) and median overall survival was 20.1 months (95%CI 18.1-21.6). Shorter time-to-treatment discontinuation was independently associated with socioeconomic deprivation, EGFR L858R mutations and distant disease at cancer diagnosis. The same factors were independently associated with shorter overall survival. Outcome estimates and predictors remained unchanged in sensitivity analyses. Conclusions. Outcomes from routine treatment with erlotinib and gefitinib in NZ patients with advanced EGFR-mutant non-squamous NSCLC are comparable with those reported in randomised trials and other healthcare system-wide retrospective cohort studies. Socioeconomic status, EGFR mutation subtype and disease extent at cancer diagnosis were independent predictors of treatment outcomes in that setting.