Drug cost and outcome in metastatic colorectal cancer with emphasis on monoclonal antibodies.

Abstract

567 Background: Patients with wild type KRAS metastatic colorectal cancer (mCRC), treated with first-line cetuximab (Cet) or bevacizumab (Bev) and chemotherapy demonstrated similar overall survival (OS). In the Western world, costs of anticancer drugs ranged from $59,000 to $100,000 per life-year gain (LYG). Hazard ratios (HR) have rarely been integrated in cost/outcome evaluation. Objective: Weigh drug cost against survival and hazard ratio (HR) in mCRC with emphasis on monoclonal antibodies (MABs). Methods: Estimated costs in United States dollars (US$) were calculated for 70 kg or 1.7/m2 patients. Costs were divided by the reported median OS gain over control in days (OSg) and by probability of survival (PoS) calculated as (1.0 – HR). Relative values (RV) were computed as 100,000/cost/outcome. Results: There was no significant difference in cost/outcome of Pan and Cet in first-line wild KRAS mCRC. At 12 week (w), the cost/LYG of panitumumab (Pan), Cet, and Bev were $64,947, $82,224, and $36,919 with RVs of 1.54, 1.22 and 2.71 respectively. Using HRs, the corresponding PoS were $140,082, $137,040, and $42,524 with RVs of 0.71, 0.73, and 2.35. Wild RAS testing improved the cost/outcome of Pan by 25%. Increasing number of cycles increased the cost/outcome and decreased the RVs of all MOAs. Conclusions: In first-line wild KRAS mCRC at 12 w, the cost/outcome of Bev was approximately 30% to 57% that of Pan and Cet. Cost/outcome of Pan significantly improved in RAS wild type. The cost/outcome of MABs was determined by the number of cycles.