Cost analysis of pre-treatment dihydropyrimidine dehydrogenase ( <i>DPYD</i> ) genotyping to reduce hospitalizations at a cancer center in the United States (U.S.).

3097 Background: Patients with certain DPYD variants are at increased risk of fluoropyrimidine (FP) related adverse events (AEs) and mortality at standard doses. We previously showed pre-treatment DPYD testing and genotype-guided FP dosing reduced severe AEs and hospitalizations in variant carriers (PMID 38935897), but testing cost remains a barrier to widespread adoption in the U.S. Herein, we performed a cost analysis of pre-treatment DPYD genotyping. Methods: Variant carrier rates, hospitalization rates, and AEs were derived retrospectively from our institutional cohort (n=442) of patients with no observed variant, dose reduced variant carriers, and standard dose variant carriers (identified reactively) receiving FP primarily for gastrointestinal cancers. All patients were genotyped and followed for three months for FP-related AEs and hospitalizations. Hospitalization cost was the weighted average cost of treating the most expensive AE experienced by the hospitalized patient. Input parameters (Table 1) were modeled using a decision tree to compare the cost of pre-treatment testing (no variant and dose reduced variant carriers) to no pre-treatment testing (no variant and standard dose variant carriers) from a health-system perspective with a three-month time horizon. The model accounted for hospitalization and genotype test costs only. Results: Pre-treatment testing resulted in a cost savings of $36.98 per patient compared to no pre-treatment testing (average per patient cost = $1,655.81 and $1,692.79, respectively). Cost savings increase to $124.39 per patient if half of those tested have insurance that reimburses the test cost. Additional savings are expected if costs for outpatient management of AEs and use of uridine triacetate in the inpatient setting are included in the model. Conclusions: Pre-treatment DPYD genotyping led to cost savings by reducing AE related hospitalizations among variant carriers. Cancer centers should adopt pre-treatment DPYD genotyping to reduce severe AEs, hospitalizations, and costs. Model inputs. Parameter Value Source No variant population prevalence 94% Institutional cohort Variant carrier population prevalence 6% Institutional cohort No variant hospitalization rate 11% Institutional cohort Dose reduced variant carrier hospitalization rate 25% Institutional cohort Standard dose variant carrier hospitalization rate 64% Institutional cohort No variant hospitalization cost $12930.67 HCUP NC Inpatient Database 2021 Dose reduced variant carrier hospitalization cost $8858 HCUP NC Inpatient Database 2021 Standard dose variant carrier hospitalization cost $8928.29 HCUP NC Inpatient Database 2021 Genotype test cost $174.81 CMS clinical laboratory fee schedule 2023 HCUP; Healthcare Cost and Utilization Project, NC, North Carolina; CMS, Centers for Medicare and Medicaid Services.