Assessment of Pharmacokinetic Interaction Between Capecitabine and Cetuximab in Metastatic Colorectal Cancer Patients.

This study focuses on the plasma disposition and metabolic activation of capecitabine (CCB) when administered alone or when combined with cetuximab (CTX).,Twenty-four chemo-naïve patients with KRAS wild-type colorectal cancer were randomized into two arms and received either CCB alone (1,000 mg/m(2) bid p.o.), followed by CCB plus CTX (loading dose (LD)=400 mg/m(2) followed by 250 mg/m(2) weekly i.v. maintenance dose) (Arm A; n=12 patients (patients)) or CCB plus CTX followed by CCB alone (Arm B; n=12 patients). Plasma samples were collected from the cubital vein and CCB, 5'-desoxy-5-fluorocytidine (5'-DFCR) and 5'-desoxy-5 fluorouridine (5'-DFUR) were quantified by a sensitive, selective reversed phase high-performance liquid chromatography (HPLC) assay. Non-compartment pharmacokinetic parameters have been calculated by Phoenix WinNonlin.,No clinically relevant impact of CTX on CCB pharmacokinetic parameters and metabolic conversion could be detected in both arms after statistical evaluation (ANOVA).,From the pharmacokinetic point of view, co-administration of CTX to CCB seems to be safe.