Cost-effectiveness analysis of cetuximab and panitumumab as first-line metastatic colorectal cancer therapies in Spain.

Abstract

e14093 Background: Current practice of clinical oncology is a challenge where increased efficacy of new-targeted therapies is counteracted by increasing costs. International financial crisis forces national health systems to optimize all therapeutic strategies maintaining clinical outcomes. Personalized medicine tries to select specific subpopulation of patients by biomarkers to refine therapeutic algorithms. We have performed a cost-effectiveness analysis to assess incremental cost-effectiveness ratio (ICER) per radiological response (RR) for cetuximab or panitumumab based scheduled as 1st line therapies for mCRC patients in Spain. Methods: Efficacy data were computed from all randomized trials (RT) that guided on-label uses of bevacizumab (K-Ras mut), panitumumab and cetuximab. Non- significant outcomes and toxicity as predictor of efficacy were excluded. Prices for drugs in Spain were assumed to represent the best-value for each drug including all possibilities to reduce pharmacy costs. For 1st line, median duration of therapy reported by RT was used to calculate the final budget. 70kg and 1.7 m were used as reference for patient dose calculations. Results: We simulated 3 main scenarios based on the possibilities of therapy for K-Ras wt patients assuming that all patients harboring a K-Ras mut. tumor received bevacizumab based chemotherapy. So, in scenario A K-Ras wt patients received weekly cetuximab combined with FOLFOX, ORR reaches 54% and global cost per RR sums €36,964. Scenario B: administering panitumumab-FOLFOX yields 51% ORR and € 38,880 per RR. Scenario C: cetuximab biweekly combined with FOLFOX yields 54% and €36,474. ICER for scenario A vs B is estimated at €4,394 per additional response. ICER for scenario C vs B yields a negative value of €4,432 per additional response. Conclusions: 1st line oxalipatin combinations of biweekly cetuximab for wt and bevacizumab for mutated patients optimize cost per additional response rate rather than panitumumab based schedules. Marginal cost differences between cetuximab and panitumumab therapies are exceeded by efficacy gap as measured by response rates in RT.