OBJECTIVES : New drug reimbursement may affect treatment decision making in practice and pharmaceutical expenditure. The aim of this study was to assess the impacts of reimbursing adoption of afatinib, as the first-line therapy on the prescribing patterns and drug expenditure for epidermal growth factor receptor mutation-positive (EGFRm+) non-small cell lung cancer (NSCLC) in Taiwan.

METHODS : Patients prescribed with any one of EGFR tyrosine kinase inhibitors (TKI), including gefitinib, erlortinib and afatinib (available in May, 2014) were analyzed in every 3-month interval (quarter) using the Taiwan national health insurance research database (2009-2017). Accuracy of budget impact analysis (BIA) for afatinib introduction before the reimbursement decision was examined. The annual volume and spending of overall three and individual EGFR TKI usage was compared over time to explore treatment expansion or treatment substitution effect of afatinib introduction. (Exchange rate: 1 USD=30.86 NTD in 2017.)

RESULTS : The overall annual EGFR TKIs spending increased 98%, with 59% before 2014 (2009-2013) and 39% after afatinib introduction (2014-2017). Afatinib treatment spending increased from $1.86 million USD in 2014 to $25.0 million USD in 2017 with 13.4 times growth, which was comparable with the BIA prediction in the first 3 years of reimbursement introduction. The number of patients per quarter received gefitinib and erlortinib both gradually increased before 2014 (286%, 215%; respectively), and sustained approximately 5400 persons/ quarter after 3rd quarter of 2014. The gefitinib spending declined 36 % (37.6 million to 24.2 million) and the erlortinib spending sustained (25.8 million to 27.1 million) over time, respectively.

CONCLUSIONS : Real-world data suggested that the increasing growth of EGFR TKIs was dominated by the increase use of afatinib as a first-line therapy option. Newly diagnosed patients with EGFRm+ NSCLC were likely to initiate with afatinib. Further research is warranted to compare the cost-effectiveness among EGFR TKIs and afatinib role in the first-line therapy.