Real-World Cost-Effectiveness of Oxaliplatin in Stage III Colon Cancer: A Synthesis of Clinical Trial and Daily Practice Evidence

Abstract

Previous cost-effectiveness analyses of oxaliplatin have been based on randomised trials whereas current Dutch policy requires evidence from daily practice. The objective of this study was to examine the real-world cost-effectiveness of oxaliplatin plus fluoropyrimidines (FL) versus FL-only as adjuvant treatment of stage III colon cancer. A Markov model was developed to estimate lifetime cost and quality-adjusted life-years from a hospital perspective. The effectiveness of the oxaliplatin arm was modelled by combining published efficacy data from the pivotal clinical registration trial (MOSAIC trial) with real-world (RW) data from a Dutch population-based observational study. RW patients were categorised into "eligible" or "ineligible", depending on whether the patients fulfilled the MOSAIC trial eligibility criteria. Ineligible RW patients (18 %) had a poorer prognosis than eligible RW patients (82 %) and MOSAIC trial patients. The effectiveness of the comparator was modelled using MOSAIC trial results. All cost inputs were based on RW patients and reported in Euro 2012. Cost-effectiveness analyses were performed for four different scenarios: (1) cost-effectiveness analyses based on MOSAIC trial patients; (2) cost-effectiveness analyses using MOSAIC and eligible RW patients; (3) cost-effectiveness analyses using MOSAIC and both eligible and ineligible RW patients, assuming oxaliplatin had an equal effect in ineligible and eligible patients; (4) cost-effectiveness analyses using MOSAIC and both eligible and ineligible RW patients, assuming oxaliplatin had no effect amongst ineligibles. For each scenario, univariate and probabilistic sensitivity analyses were undertaken. MOSAIC trial patients and eligible RW patients treated with oxaliplatin had comparable 2-year disease-free survivals (79.5 vs. 78.4 %). Oxaliplatin showed an incremental QALY gain of 1.02, 1.13, 1.17 and 0.93 and incremental cost of <euro>9,961, <euro>11,055, <euro>9,814 and <euro>11,854 in scenarios 1-4, respectively. The corresponding incremental cost-effectiveness ratios (ICERs) were <euro>9,766, <euro>9,783, <euro>8,388 and <euro>12,746 in scenarios 1-4, respectively. In all scenarios, univariate and probabilistic sensitivity analyses indicated that the ICERs are acceptable and robust under a wide range of model assumptions. The ICERs of the different scenarios that resulted from combining MOSAIC trial data with data from Dutch daily practice all suggest that FL + oxaliplatin is cost-effective versus FL alone in the adjuvant treatment of colon cancer. This article illustrates how one could design and implement a real-world cost-effectiveness study to yield internally valid results that could also be generalisable.