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Comparative Pharmacokinetic Study of Continuous Venous Infusion Fluorouracil and Oral Fluorouracil With Eniluracil in Patients With Advanced Solid Tumors

2002; Lippincott Williams & Wilkins; Volume: 20; Issue: 6 Linguagem: Inglês

10.1200/jco.2002.20.6.1683

1527-7755

Alex A. Adjei, Joel M. Reid, Robert B. Diasio, Jeff A. Sloan, Deborah A. Smith, Joseph Rubin, Henry C. Pitot, Steven R. Alberts, Richard M. Goldberg, Lorelei J. Hanson, Pamela J. Atherton, Matthew M. Ames, Charles Erlichman,

Neutropenia and Cancer Infections

PURPOSE: To compare the pharmacokinetics of continuous venous infusion (CVI) fluorouracil (5-FU) with that of oral eniluracil/5-FU and to describe toxicities and clinical activity of prolonged oral administration of eniluracil/5-FU. PATIENTS AND METHODS: A randomized, open-label, cross-over study compared CVI 5-FU to an oral 5-FU/eniluracil combination. Seventeen patients (arm A) were randomly assigned to receive eniluracil/5-FU combination tablets (10:1 mg/m 2 BID for 7 days) during the first study period, followed by 5-FU (300 mg/m 2 CVI for 7 days) during period 2, with a 14-day washout between periods. Sixteen patients (arm B) received treatment in the opposite sequence. In period 3, all patients received eniluracil/5-FU tablets BID for 28 days. Plasma levels of 5-FU during CVI and oral administration were analyzed in periods 1 and 2. Dihydropyrimidine dehydrogenase (DPD) activity was determined by measuring plasma uracil, urinary α–fluoro-β-alanine, and peripheral-blood mononuclear cell (PBMC) DPD activity. RESULTS: There were no grade 3 or 4 toxicities in either arm. Partial responses were observed in three patients. Another three patients had stable disease for ≥ 3 months. Eniluracil and 5-FU pharmacokinetics were similar to those observed in previous studies and were unaffected by administration sequence. The mean ± SD steady-state plasma concentration (C P ) and area under the curve (AUC) 144-168h for CVI 5-FU (104 ± 45 ng/mL and 2,350 ± 826 ng·h/mL, respectively) were three-fold greater than those for oral 5-FU (38.1 ± 7.7 ng/mL and 722 ± 182 ng·h/mL, respectively [P < .00001]). Individual 5-FU concentrations during CVI were highly variable, whereas those after eniluracil/5-FU were very reproducible. DPD activity in PBMCs before each study period was normal. CONCLUSION: Both CVI 5-FU and oral eniluracil/5-FU were well tolerated, with moderate activity in these heavily pretreated patients. However, 5-FU steady-state C P and AUCs achieved with oral eniluracil/5-FU were significantly less than with CVI 5-FU.