OBJECTIVES: Colorectal cancer is the second cause of cancer related deaths in Europe. Approximately 75% of patients with colorectal cancer will present metastasis. After two treatment lines, the prognosis is poor and the average survival is about 4–6 months with best supportive care (BSC). Nonetheless, one third of metastatic colorectal cancer (mCRC) patients are still in a good condition and willing to receive further therapy. This study aimed to assess the cost-effectiveness of trifluridine/tipiracil (TAS-102) for third-/fourth-line treatment of mCRC in Portugal.

METHODS: A partitioned survival model was developed to represent the natural history of mCRC, considering a lifetime horizon. BSC was set as comparator. Efficacy and safety derived from a pooled analysis of phase II (J003) and III (RECOURSE), multicentre, randomized trials. Parametric survival analyses were performed and the best fitting survival function was selected using Akaike's Information Criterion. Costs were retrieved from public sources. A 5% annual discount rate was adopted for costs and effects. Results were expressed in incremental costs per life year (LY).

RESULTS: On average, trifluridine/tipiracil is expected to increase mCRC patients’ undiscounted life expectancy by 0.27 LYs relative to BSC (11.1 versus 7.8 months). Trifluridine/tipiracil is expected to augment overall treatment costs by 9,899€/patient (discounted) mainly related to higher drug costs and higher patients’ survival, corresponding to an incremental cost-effectiveness ratio (ICER) of 39,487€/LY. The sensitivity analysis performed for costs and effectiveness parameters revealed low variation, with LYs gained and ICERs ranging between 0.24-0.26 and 37,489-41,508€/LY. The probabilistic sensitivity analysis confirmed that trifluridine/tipiracil is estimated to present an 80% probability of being cost-effective at a threshold of 50,000€/LY.

CONCLUSIONS: In this later line setting with limited treatment options, trifluridine/tipiracil is expected to provide a clinically meaningful life expectancy increase at an incremental cost per life year gained within an acceptable range.