Objective: Metastatic colorectal cancer with KRAS wild type is treated using a range of drug regimens, including fluorouracil, irinotecan, and Leucovorin(FOLFIRI)plus bevacizumab(Bmab), cetuximab(Cmab), or panitumumab(Pmab). The present study aimed to identify the optimal regimen using a decision analysis method, in combination with clinical and economic evidence.
Method: A simple Markov model with a monthly cycle time was constructed. Probabilistic variables for input into the model were derived from randomized controlled trials. Direct costs for the drugs, laboratory analyses, and medical staff were calculated and used in the model.
Results: The expected survival times and costs of FOLFIRI alone and combination therapies were 20.9 months and 2,299,198 yen for FOLFIRI, 29.9 months and 8,929,888 yen for Bmab, 27.8 months and 11,811,849 yen for Cmab, and 22.6 months and 8,795,622 yen for Pmab. The incremental cost-effectiveness ratios to FOLFIRI were 736,743 yen/month for Bmab, 1,378,645 yen/month for Cmab, and 3,821,426 yen/month for Pmab.
Conclusions: These findings suggested that these regimens were not sufficiently cost-effective, although they have excellent therapeutic efficacy. From the economic point of view, these combination regimens were inferior to FOLFIRI alone.