Pharmacokinetics of oxaliplatin in patients with severe hepatic dysfunction

Data are lacking on the pharmacokinetics of oxaliplatin in patients with severe hepatic dysfunction. The aim of this study was to determine the pharmacokinetic parameters of platinum after administration of oxaliplatin in cancer patients with severe hepatic impairment due to extended metastases into the liver.

Two female breast cancer patients and one male colon cancer patient were treated with oxaliplatin monotherapy at 130 mg/m² given as a 3-h intravenous infusion. The patients exhibited bilirubin concentrations of 9.6, 22.5 and 41.1 mg/dl indicating severe hepatic dysfunction. Serial blood samples were collected immediately before treatment, and at fixed intervals up to 27 h after start of therapy. Platinum concentrations in plasma, ultrafilterable plasma, and whole blood were determined using a validated flameless atomic absorption spectrometry (FAAS) method. Pharmacokinetic data analysis was performed assuming a two-compartment model. Individual pharmacokinetic parameters were compared with a reference population with normal hepatic function.

The area under the curve (AUC from 0 to infinity) as well as the elimination half-life of platinum in ultrafilterable plasma were substantially increased and clearance accordingly decreased in the three patients with severe hepatic dysfunction. In plasma and whole blood, the deviations from the reference population were less pronounced. However, partial AUC from 0 up to 2 h after end of infusion reflecting better the exposure with cytotoxic platinum species was not different or only slightly altered. Moreover, no acute oxaliplatin-associated neurotoxicity was observed.

The comparable platinum exposure early after administration in conjunction with the lack of acute toxicity do not support a dose reduction of oxaliplatin in patients with markedly elevated bilirubin concentrations. However, a larger number of patients must be examined before valid dose recommendations can be derived.