Combined 5-fluorouracil and floxuridine administered as a 14-day infusion. A phase I study

Continuous infusion of chemotherapy: focus on 5-fluorouracil and fluorodeoxyuridine

Continuous infusion of chemotherapy is one of the developments to try to improve the treatment of metastatic cancer. There is a sound theoretical rationale to deliver cytotoxic drugs as a continuous infusion. Furthermore, the development of reliable venous access devices and portable infusion pumps enables patients to be treated in an ambulatory setting. This review focuses on the continuous infusion of the most frequently used drugs: 5-fluorouracil (5-FU) and fluorodeoxyuridine (FUDR). An overview is given of both preclinical studies and studies in humans. Continuous infusion of 5-FU and FUDR has proven to be feasible in all studies. However, the results (response rate and especially survival) are rather disappointing. So far, continuous infusion of cytostatic drugs can still be considered as an experimental procedure. Whether protracted, intermittent of circadian modulated continuous infusion is the optimal treatment schedule has still to be proven in future studies. Furthermore, studies are needed to demonstrate whether dose intensity for most tumours is important for treatment outcome. Also, studies are needed to investigate quality of life and economic issues.

Infusional cancer chemotherapy: historical evolution and future development at the Cancer Center of Boston

Clinical studies of infusional chemotherapy at The Cancer Center of Boston began in 1980 at the New England Deaconess Hospital and from 1986 to the present have continued under the auspices of a network of free-standing ambulatory cancer treatment centers in Massachusetts. Over 50 peer-reviewed articles on infusional chemotherapy and 3 textbooks on the topic have been published by clinical investigators associated with The Center, including phase I, II, and III trials, multidrug infusion programs, and combined chemo/radiotherapy programs. Bringing together the total experience in this review provides a perspective to address those areas that have been inadequately explored and a framework for future development in the field. This paper represents a comprehensive synthesis and analysis of clinical infusional studies carried out at The Center to the present with the goal of achieving those objectives.

A review of the stability and compatibility of antineoplastic drugs for multiple-drug infusions

It is important that the stability of reconstituted parenteral antineoplastic agents be established, particularly in the context of ambulatory infusion systems for delivery. The stability of selected agents within each of the five classes of compounds (antimetabolites, alkylating agents, antibiotics, alkaloids and glycosides, and metals) is reviewed from the literature together with additional data from studies carried out using high-performance liquid chromatographic (HPLC) technology in clinically applicable volumes and concentrations for ambulatory infusion. The stability of reconstituted drugs varies from a few minutes (mecloethamine) to many months (FU). Compatibility data on two- and three-drug admixtures of cytotoxic agents are reported for a number of common multidrug regimens. Tabular presentation of the drug-drug compatibilities and incompatibilities is included along with a discussion of the mechanisms for drug-drug interaction. The use of a broad spectrum of compatible cytotoxic drugs is possible, including fluoropyrimidine-, anthracycline-, and platinum-based combinations, providing the capability of carrying out multidrug infusions for 4-7 days in an ambulatory delivery system.

Biochemical pharmacology and analysis of fluoropyrimidines alone and in combination with modulators

After more than three decades since their introduction, fluoropyrimidines, especially FUra, are still a mainstay in the treatment of various solid malignancies. The antitumor effects of fluoropyrimidines are dependent upon metabolic activation. FdUMP, FUTP and FdUTP were identified as the key cytotoxic metabolites that interfere with the proper function of thymidylate synthase and nucleic acids. The relevance of these metabolites is cell-type specific. Recently, fluorouridine diphospho sugars have been detected, but the precise function of this class of metabolites is currently unknown. In mammalian systems fluoropyrimidines and their natural counterparts share the same metabolic pathways since the substrate properties in enzyme-catalyzed reactions are frequently comparable. Ongoing studies indicate that the metabolism and action of fluoropyrimidines exhibit circadian rhythms, which appear to be due to variations in the activity of metabolizing enzymes. Essential for the expanding knowledge of the pathways and effects of fluoropyrimidines has been the constant improvement of analytical methods. These include ligand binding techniques, numerous dedicated HPLC systems and 19F-NMR. Because the overall response rates achieved with fluoropyrimidines are modest, strategies based on biochemical modulation have been devised to enhance their therapeutic index. Biochemical modulators include a wide range of various compounds with different modes of action. In recently completed clinical trials, combinations of FUra with leucovorin, a precursor for 5,10-methylene tetrahydrofolate, or with levamisole, an anthelminthic with immunomodulatory activity, appeared to be superior to FUra alone. At the preclinical level combinations of fluoropyrimidines with, e.g. interferons or L-histidinol were demonstrated to be interesting candidates for further testing. The future therapeutic utility of fluoropyrimidines will depend on both the improvement of combination regimens currently used in the treatment of cancer patients and the judicious clinical implementation of promising experimental modulation strategies. Moreover, novel fluoropyrimidines with superior pharmacological properties may become important as part of or instead of modulation approaches.