Cost-effectiveness analysis of capecitabine compared with bolus 5-fluorouracil/l-leucovorin for the adjuvant treatment of colon cancer in Japan.

OBJECTIVE: A cost-effectiveness analysis of oral capecitabine versus intravenous bolus 5-fluorouracil/l-leucovorin (FU/LV) as adjuvant therapy in patients with stage 3 colon cancer was performed from a Japanese healthcare payer perspective.

METHODS: Adjuvant therapy comprised 24 weeks of treatment with either oral capecitabine 1250 mg/m(2) twice daily on days 1-14 of a 21-day cycle or intravenous bolus FU 500 mg/m(2) and LV 250 mg/m(2) weekly for 6 weeks of an 8-week cycle (Roswell Park regimen). The analysis comprised short-term (1 year after initiation of adjuvant therapy) and long-term (up to 15 years) components. The long-term analysis involved a three-state (disease-free, recurrence and death) Markov model. Estimates for transition probabilities, costs and utilities were derived from the X-ACT trial, a Japanese phase II trial, and other published sources. Cost estimates were considered from the perspective of a healthcare payer. Costs were expressed in Japanese Yen (yen), year 2007 values. A discount rate of 3% was applied to costs and outcomes. Cost effectiveness was expressed as a cost per QALY. The effects of uncertainty were explored through one-way and probabilistic sensitivity analyses.

RESULTS: In the 1-year analysis, direct costs were yen440,000 ($US4000) less per patient with capecitabine than with FU/LV. In the long-term analysis, differences between treatments in direct medical costs ranged from yen470,000 ($US4300) to yen580,000 ($US5300) depending on the time horizon used. Capecitabine was also projected to increase the number of QALYs compared with FU/LV. The sensitivity analysis suggested that the model outcome was robust. The probabilistic sensitivity analysis estimate of capecitabine being the dominant regimen was 96.6% at a zero willingness to pay. Direct costs remained lower with capecitabine if the price of generic LV was >OR=50% of the branded product.

CONCLUSION: This analysis suggests that capecitabine improves health outcomes and lowers direct costs compared with bolus FU/LV (i.e. dominant treatment strategy) when used as adjuvant therapy in patients with stage 3 colon cancer in Japan.