Clinical, pharmacokinetic and pharmacodynamic evaluations of metronomic UFT and cyclophosphamide plus celecoxib in patients with advanced refractory gastrointestinal cancers

AIMS: To evaluate UFT and cyclophosphamide (CTX) based metronomic chemotherapy plus celecoxib (CXB) for the treatment of patients with heavily pre-treated advanced gastrointestinal malignancies. METHODS: Thirty-eight patients received 500 mg/mq(2) CTX i.v bolus on day 1 and, from day 2, 50 mg/day CTX p.o. plus 100 mg/twice a day UFT p.o. and 200 mg/twice a day CXB p.o. Tegafur, 5-FU, 5-FUH(2), GHB and uracil pharmacokinetics were assessed. Plasma vascular endothelial growth factor (VEGF), soluble VE-cadherin (sVE-C) and thrombospondin-1 (TSP-1) levels were detected by ELISA and real-time PCR of CD133 gene expression on peripheral blood mononuclear cell was also performed. RESULTS: Seventeen patients (45%) obtained stable disease (SD) with a median duration of 5.8 ms (range, 4.2–7.4). Median progression free survival (PFS) and overall survival (OS) were 2.7 ms (95% CI, 1.6–3.9 ms) and 7.1 ms (95% CI, 4.3–9.9 ms), respectively. No toxicities of grade >1 were observed. Pharmacokinetics of 27 patients (13/14, SD/progressive disease, PD) after the first treatment of UFT revealed that 5-FU AUC and C(max) values greater than 1.313 h × μg/ml and 0.501 μg/ml, respectively, were statistically correlated with stabilization of disease and prolonged PFS/OS. VEGF and sVE-C plasma levels were greater in the PD group when compared to SD group. CD133 expression increased only in the PD patients. CONCLUSION: Metronomic UFT and CTX with CXB in heavily pre-treated gastrointestinal patients were well tolerated and associated with interesting activity. Potential predictive pharmacokinetic parameters and pharmacodynamic biomarkers have been found.