Effect of Hyaluronidase on the Pharmacokinetics of Free and Total Platinum Species after Intra-Arterial Cisplatin in Refractory Patients with Colorectal Liver Metastases

Abstract

A pharmacokinetic study was carried out in patients with unresectable colorectal liver metastases who had primarily been included in a phase II trial of intra-arterial cisplatin (DDP) plus intravenous fluorouracil. Ten patients of those accrued for the clinical study underwent the pharmacokinetic investigation upon liver progression of the disease. Four patients were treated with DDP (24 mg/m(2)) through short intra-arterial infusion (baseline study) and 4 patients received intra-arterial hyaluronidase (HY, 100 000IU) 2 minutes before DDP infusion. Two additional patients were treated with both DDP alone and DDP + HY. Plasma concentrations of total and free platinum (Pt) were consistently lower than baseline in the presence of HY. HY administration resulted in a longer terminal half-life (2.1 ± 0.7 vs 1.0 ± 0.2 days, p < 0.05), a reduced area under the plasma concentration-time curve from 0 to 2 hours (AUC0-2h) [0.08 ± 0.009 vs 0.12 ± 0.017 g/L•min, p < 0.01], and an increased volume of distribution, both initially (11.7 ± 3.4 vs 6.6 ± 2.1L, p < 0.05) and at steady-state (43.0 ± 10.8 vs 22.1 ± 8.8L, p < 0.05), for total Pt. However, significant HY-related effects on the overall plasma exposure (AUC0-∞) to total Pt or on the total body clearance were not observed. HY treatment was also associated with a lower plasma concentration at time zero (C0) [p < 0.01 ] and AUC0-2h (p < 0.02), and a higher plasma clearance (p < 0.02) and apparent volume of distribution (p < 0.05), for free Pt. Renal clearance (CLR) and cumulative urinary excretion of Pt were significantly increased (p < 0.01) by HY, while fluid output was not significantly affected. The increase in both CLR and the extent of Pt distribution was not due to a protein binding drug interaction nor to a reaction between DDP and HY in the plasma. Combined treatment with HY yielded a clinically acceptable toxicity.