Background: Afatinib is one of three tyrosine kinase inhibitors (TKI) approved in the US for the first-line treatment of patients with metastatic non-small cell lung cancer (mNSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions (Del19) or exon 21 (L858R) substitution mutations. However, afatinib is the only TKI to have demonstrated significant improvement in both progression-free survival and overall survival in the EGFR Del19 mutation subgroup versus chemotherapy.
Objectives: To estimate the budget impact of adding afatinib to a US health plan formulary for the first-line treatment of mNSCLC patients with EGFR Del19 mutations. Methods: A decision-analytic model was developed to evaluate the budget impact of adding afatinib to the current mix of therapies for the first-line treatment of mNSCLC patients with EGFR Del19 mutations, over a 3-year time horizon. The model compared the total annual costs (i.e. therapy-related and disease management costs) with and without afatinib on a formulary of a health plan with 1 million covered lives. The number of patients eligible for treatment was estimated using published incidence data. Therapies included in the model were afatinib, erlotinib, gefitinib, and chemotherapy doublets (paclitaxel/carboplatin, pemetrexed/cisplatin). Market share of afatinib was assumed to increase 5% each year. The mean time spent by patients in progression-free and progressive disease states were based on survival data from clinical trials and a network meta-analysis. Therapy-related costs included monthly drug acquisition and administration costs and adverse reaction management costs. Disease management costs were also assessed in the model. A one-way sensitivity analysis was performed by changing key input parameter values.
Results: Assuming afatinib uptake of 5% annually, the estimated total annual costs to the health plan decreased by $79 in year 1, and increased by $2,554 and $14,494 in years 2 and 3. Per member per month (PMPM) budget changes were $0.0000, $0.0002, $0.0012 in years 1, 2, and 3. Increases in budget were due in part to the increase in mean survival time of patients as a result of adding afatinib. Sensitivity analyses showed that results were most sensitive to afatinib acquisition cost and the mean survival times for afatinib patients.
Conclusions: Under current model assumptions, adding afatinib for the first-line treatment of mNSCLC patients with EGFR Del19 mutations would result in minimal budget impact to a US health plan.
