An economic analysis of the INTEREST trial, a randomized trial of docetaxel versus gefitinib as second-/third-line therapy in advanced non-small-cell lung cancer

Background: The INTEREST (IRESSA NSCLC Trial Evaluating Response and Survival against Taxotere) trial compared gefitinib with docetaxel (Taxotere) in pretreated advanced non-small-cell lung cancer (NSCLC). Noninferiority for overall survival was concluded. Gefitinib had a better toxicity profile and greater improvements in quality of life (QoL). We undertook a cost-consequence analysis to estimate the direct medical costs of gefitinib compared with docetaxel. Patients and methods: Summary data from INTEREST were used to derive resource utilization and direct costs from treatment start until drug discontinuation. Costs for treatment, adverse events, outpatient visits and investigations were calculated. Mean total cost-per-patient-per-arm was determined, and incremental cost was calculated. Utility values were generated from Functional Assessment of Cancer Therapy - Lung scores and compared between arms. Results: Incremental mean overall cost per patient for gefitinib over docetaxel was CAD$5161. Drug was the major contributor to overall cost in both arms. Longer mean duration of gefitinib therapy (134 versus 91 days) contributed to the incremental cost difference. The cost per 21-day cycle was similar in both arms ($1963 docetaxel, $2095 gefitinib). Conclusion: The modest increase in cost associated with gefitinib supports its use as an alternative to docetaxel as second-line treatment of advanced NSCLC, particularly given the improvements in QoL, patient preference for oral therapy and better toxicity profile with gefitinib.