The physiologic disposition of dichloromethotrexate-CI36in man

Single-agent and combination-drug regional chemotherapy for head and neck cancer using an implantable infusion pump

Chemotherapy delivered through angiographically placed catheters requires patient hospitalization, and is usually limited to short-term infusions. Treatment given through surgically placed catheters with external portable infusion pumps permits greater patient freedom and longer infusion durations. However, some patient restrictions remain, and thrombotic or infectious complications are common with long-term therapy. A totally implantable pump has allowed long-term intraarterial therapy in an outpatient population. Patient activity was unrestricted, and the complication rate has been low. This system has been used to deliver single-agent therapy with FUdR, dichloromethotrexate or bleomycin, and combination-drug treatment with cisplatin + FUdR or bleomycin + mitomycin C + dichloromethotrexate. The majority of patients have responded to at least one drug program. Seven of 14 patients who had pumps implanted over 1 year ago have received therapy for at least 1 year, and four patients have had functioning system for over 2 years. Systemic toxicity (except for nausea and vomiting with cisplatin) has been uncommon. Further clinical experience with these programs will be necessary to fully establish the objective response rate. However, the Infusaid Pump has proven safe, reliable and has high patient acceptance.

Clinical and laboratory reevalution of dichloromethotrexate

Clinical and pharmacologic effects of dichloromethotrexate (DCM) were reevaluated by an intermittent intravenous large dose schedule in patients with advanced malignancies. DCM was tolerated without Leucovorin (calcium folinate) in man, even when the initial immunoassayable DCM level approached 10(-3) M. Hepatic dysfunction occurred more frequently at high doses. Hematologic toxicity was not dose-limiting. Plasma decay of DCM was comparable to that of methotrexate (MTX). Of 50 patients treated, five including two with hepatic metastasis from colon carcinoma, responded with more than 50% regression of tumor. In vitro comparison of DCM and MTX in Molt 3 cells revealed that DCM was slightly more inhibitory than MTX on an equimolar basis. In the presence of 2.5 g/dl of human serum albumin (HA), however, inhibitory effects of DCM decreased markedly. The decreased biologic effects of DCM compared to those of MTX are due to much higher binding to HA by DCM. This phenomenon appears to explain all of the clinical and pharmacologic characteristics of DCM.