Real-world cost-effectiveness of oxaliplatin in stage III colon cancer: a synthesis of clinical trial and daily practice evidence

Abstract

Objectives: 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.

Methods: 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.

Results: 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.

Conclusions: 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.