A pharmacokinetic comparison of intravenous versus intra-arterial folinic acid.

Recent clinical trials have suggested that a combination of folinic acid and 5-fluorouracil (5-FU) may improve response rates and survival in patients with advanced colorectal cancer. However, this regimen has been complicated by potentially life threatening toxicity. Regional delivery of folinic acid via a hepatic artery catheter might be expected to reduce systemic exposure and subsequent adverse effects. The present study compared the pharmacokinetic profiles of intravenous and intra-hepatic arterial infusions of folinic acid in patients with colorectal liver metastases (n = 6) who were being treated with weekly regional infusions of 5-FU. The mean area under the plasma concentration--time curve, the peak plasma concentration and the steady state volume of distribution were 163 micrograms ml-1 h-1 (SD 41), 18.5 micrograms ml-1 (SD 1.2) and 7.41 m-2 (SD 0.44) respectively following intravenous administration of folinic acid compared with 142 micrograms ml-1 h-1 (SD 45), 14.8 micrograms ml-1 (SD 2.4) and 11.21 m-2 (SD 1.22) following intra-hepatic arterial administration (P less than 0.05). Regional folinic acid was therefore associated with a statistically significant reduction in systemic exposure compared with the intravenous route.