A prospective economic analysis of cost-effectiveness of cetuximab for metastatic colorectal cancer patients from the NCIC CTG and AGITG CO.17 trial

Abstract

6528 Background: CO.17 study is the first intergroup (Canadian/Australian) trial, that prospectively collected resource utilization and utility data for cetuximab (N=283) vs. best supportive care alone (BSC; N=274) in advanced colorectal cancer patients. A cost-effectiveness analysis was conducted based on the improved survival, higher cost of cetuximab and variable costs across countries from the perspective of the Canadian health care system. Methods: The mean difference in trial survival times between cetuximab and BSC was calculated. Direct medical resource utilization data was collected during the trial from the time of randomization until death or study closure. Trial resources included medications physician visits, toxicity management, institutionalization, emergency department visits and hospitalizations. Mean overall incremental cost (2007 $CAN-provincial sources) was determined. Drug acquisition costs (DAC) for cetuximab, based on several countries, were used to determine the incremental cost effectiveness ratio (ICER) in dollars per life-year gained (LYG). Sensitivity analyses for cetuximab DACs were conducted. Bootstrapping (1,000 iterations) provided 95%CI. Results: Mean incremental trial survival was 0.12 years. Preliminary results showed variability in the ICER, where DAC was the cost driver. At the lowest DAC ($2.94/mg), overall incremental costs were $19,361 for cetuximab compared to BSC, with incremental values of $1,086 for toxicity management, $1,016 for hospitalization, and $410 plus $81 for oncologist and family physician visits respectively. The ICER for cetuximab was $183,287/LYG (95%CI: $114,139-$581,027) using a $2.94/mg DAC (Switzerland), $198,467/LYG ($123,509-$558,270; $3.24/mg-Canadian suggested) and $375,047/LYG ($237,139- $1,233,111; $6.73/mg US). Sensitivity analyses produced an ICER of $50,000/LYG at $0.28/mg; $100,000/LYG at $1.30/mg and $200,000/LYG at $3.27/mg. Cost per quality adjusted life year will also be determined. Conclusions: Cetuximab showed high and variable ICERs dependent on a range of DACs in CO.17 advanced colorectal cancer patients. Utility will impact the incremental value. No significant financial relationships to disclose.