Investigating the utilization of pharmacokinetic-guided fluorouracil in colorectal cancer.

e13109 Background: Fluorouracil (FU) has remained the cornerstone of colorectal cancer (CRC) therapy for > 40 years; however, recent evidence suggests inter-individual pharmacokinetic (PK) variability in response. Methods: A total of 58 CRC patients from 6 academic and community sites received mFOLFOX6 (FU 2400 mg/m2 over 46 hours every 2 weeks) +/- bevacizumab. FU doses for cycles 2-4 were adjusted based on an algorithm to target an AUC of 20-25 mg*h/L. Peripheral blood was obtained 2-46 hours post beginning of infusion (BOI) and AUCs were determined using an immune-based assay (OnDose). The primary objective of this study is to describe the feasibility of PK-guided FU in clinical practice using descriptive statistics with a secondary objective of toxicity assessment. Results: Mean AUC post cycle 1 in evaluable patients (n=39) was 19.8 +/- 6.3 mg*h/L (range 7-38) with 31% within, 51% under, and 18% over the AUC target. Based on cycle 1 results, the mean dose estimated to achieve AUC 20-25 mg*h/L would be...