A pharmacokinetic model and the clinical pharmacology of cis-platinum, 5-fluorouracil and mitomycin-C in isolated pelvic perfusion

Purpose: An isolated pelvic perfusion technique using multiple agents was u sed both in patients with unresectable recurrent pelvic neoplasms and as a preoperative therapy for advanced pelvic malignancy. Methods: The technique consisted of vascular occlusion via transfemoral balloon catheters, circul ation and drug infusion using standard hemodialysis technology, and a 45-mi n isolation period. Blood and urine samples were analyzed for the levels of cis-platinum (17 patients, 21 courses of therapy, 50-100 mg/m(2), infusion 0-10 min), 5-fluorouracil (12 patients, 14 courses, 1500 mg/m(2), infusion 1/3 dose 0-1 min, 2/3 dose 1-20 min) and mitomycin-C (11 patients, 14 cour ses, 10-30 mg/m(2): infusion 10-30 min). An empirical, four-compartment pha rmacokinetic model was developed to establish drug distribution curves for the pelvic and systemic circulations and to yield valid estimates of the ph armacokinetic parameters. Results: Pelvic isolation of drug was demonstrate d by the pelvic-systemic drug exposure ratios of 6.0:1 for cis-platinum, 8. 4:1 for 5-fluorouracil and 9.0:1 for mitomycin-C. Isolation at the L3-4 int erspace resulted in minor urine drug elimination during isolation (cis-plat inum 7.2% of drug, 5-fluorouracil 2.4% and mitomycin-C 2.5%). Because drug infusion was limited to the first 20 min of isolation, drug levels at the e nd of the isolation period were reduced to the extent that no extracorporea l drug removal mechanism was needed. Conclusion: These pharmacokinetic resu lts indicate that this isolation technique has the potential to provide inc reased therapeutic indices and is a suitable system for evaluating fast-act ing highly toxic experimental drugs to human pelvic cancers which are poorl y responsive to conventional clinical protocols.