Impact of country-specific health economic guidelines on cost-effectiveness (CE) estimates: An illustrative study of the CE of cetuximab in the first-line (1L) treatment of RAS wild-type (wt) metastatic colorectal cancer (mCRC).

702Background: Adding cetuximab to conventional 1L chemotherapy (FOLFIRI or FOLFOX) improves survival outcomes in patients with RASwt mCRC. Conflicting evidence exists regarding the CE of cetuximab in mCRC, due in part to differences in country-specific health technology assessment (HTA) guidelines. Methods: CE estimates for the 1L treatment of RASwt mCRC with FOLFIRI or FOLFOX ± cetuximab were calculated for the UK (NICE), Brazil, Netherlands, and Belgium using a Markov cohort model populated with country-specific HTA requirement inputs and assumptions. Model outcomes were treatment costs, life-years (LY) or quality-adjusted LY (QALY) gained, and the incremental CE ratio (ICER). ICERs were compared against CE thresholds. Results: Country-specific HTA guidance resulted in differing CE outcomes for patients with RASwt mCRC receiving FOLFIRI or FOLFOX ± cetuximab (Table). Conclusions: We applied our Markov model to four markets, incorporating country-specific HTA requirements into our calculations. Although...