Purpose: We assessed the impact of hepatic dysfunction on the safety and pharmacology of gemcitabine/capecitabine in patients with advanced pancreatico-biliary cancer.
Methods: We included 12 patients receiving 3 weekly gemcitabine 1,000 mg/m(2) day 1, 8 and oral capecitabine 650 mg/m(2) b.i.d. over 2 weeks until disease progression or intolerable toxicity. Patients were included into one normal hepatic function cohort [total bilirubin (TB) ≤15 μmol/L] and 3 cohorts with increasing TB (16-39, 40-80, >80 μmol/L). Three patients with a creatinine clearance <60 ml/min were also included. Patients were sampled for gemcitabine, difluoro-deoxy uridine, intracellular gemcitabine triphosphates, capecitabine, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine and 5-fluorouracil up to 4 h after initiation of chemotherapy on day 1, and up to 90 min on day 8. All compounds were analyzed using validated liquid chromatography-tandem mass spectrometry. Nonlinear mixed-effect modeling was used for population analysis.
Results: Hepatic dysfunction was caused by intrahepatic cholestasis in 4 out of 8 patients (50 %) and extrahepatic cholestasis in another 4 patients (50 %). Dose-limiting toxicity was increasing hyperbilirubinemia and severe neutropenia in 2 patients each. Hepatic dysfunction was not associated with dose-limiting toxicity or severe hematological or non-hematological toxicity. However, hepatic dysfunction was associated with low clearance of both gemcitabine (p = 10(-3)) and capecitabine (p = 10(-5)), and low intracellular gemcitabine triphosphate concentrations (p = 10(-3)).
Conclusions: Gemcitabine/capecitabine can be given at the standard dose in patients with severe hyperbilirubinemia, though the present data suggest that gemcitabine's activity may be limited due to poor intracellular activation. In patients with severe hyperbilirubinemia, initial monotherapy with capecitabine should be considered, followed by the addition of gemcitabine with improving hyperbilirubinemia.