DPD deficiency: Medicoeconomic evaluation of pretreatment screening of 5-FU toxicity.
410 Background: Deficiency of DPD activity is associated with severe toxicity or even death after the first two cycles 5-fluorouracil (5-FU) based of chemotherapy. The objective of this study was to assess the cost-effectiveness of a screening test before treatment of the deficiency of DPD activity combining two approaches (genetic and phenotype (UH2 / U)). The main measure of effectiveness was the number of avoided severe toxicities (grade 3-4), but the number of quality adjusted life days was the secondary endpoint. Methods: The analysis was based on retrospective data from a population of patients treated for colorectal cancer. 856 patients were screened (5-FUODPM Tox, ODPM, France) before being treated with adjusted doses (5-FUODPM Protocol, ODPM, France) versus a population of 886 patients treated according to standard doses (2400 mg/m²). The main point of view was society perspective and the time horizon was 2 cycles of chemotherapy. A multi-state Markov-type was used to estimate the mean cost and results for each of the two strategies. The cost of the strategy with screening was composed of the cost of the screening test and the cost of remaining toxicities, the cost of the standard strategy was just the cost of toxicities. The incremental cost-effectiveness ratio (ICER) was calculated: (COSTStandard - COSTWithScreening)/(EffStandard - EffWithScreening) COSTA : Cost of the strategy A, EffA : Effectiveness of the strategy A. Results: In the screened and adapted arm, the prevalence of severe toxicities at 1 cycle of chemotherapy was 0.5%, at 2 cycles was 0.9%. In the arm with standard doses, they were 5.80% and 6.90%, respectively. Any toxicity associated death was observed in the screened arm versus 1 death in the standard arm. The screening strategy was dominant, it allowed avoiding toxicities and saving money. The avoided cost per patient screened was 313 € for two cycles of treatment and a saving of 2780 € per toxicity avoided. The incremental net benefit (INB) per patient screened is 426 €. Conclusions: Pre-treatment screening test combining genetic and phenotype reduced the incidence of toxicities associated with 5-FU, it avoided deaths due to 5-FU and its additional cost was less than the cost of care of toxicity that it avoided.