Continuous Intravenous Administration of l-(2-Tetrahydrofuryl)-5-Fluorouracil [FT] by Intravenous Hyperalimentation (IVH) -- Stability of FT in IVH Solution and Tumor Levels of 5-Fluorouracil (5-FU) --

The continuous intravenous administration of l-(2-tetrahydrofuryl)-5-fluorouracil(FT) to colorectal cancer patients was studied in regard tothe stability of FT in intravenous hyperalimentation (IVH) solutionsand tumor levels of 5-fluorouracil (5-FU). FT was very compatiblewith IVH solutions, because the decomposition of FT in IVH solutionwas very low, 3%. High levels of 5-FU, which is an active metaboliteof FT, were obtained in the tumors, averaging 0.369 mcg/g. Theratios of 5-FU levels in the tumor to those in serum and normaltissues were 13.6 and 3.7. respectively. The difference in 5-FUlevels between normal tissues and the tumors was statisticallysignificant (P<0.01). Therefore, continuous intravenous administrationof FT should be widely used to treat patients with colorectalcancer, as the method of administration of antitumor agents.     

Sensitivity test for 5-fluorouracil and its analogues, 1-(2-tetrahydrofuryl)-5-fluorouracil, uracil/1-(2-tetrahydrofuryl)-5-fluorouracil (4:1) and 1-hexylcarbamoyl-5-fluorouracil, using the subrenal capsule assay

The chemosensitivity of 20 human neoplastic tissues including 13 gastric and 7 colorectal cancers was tested using 5-fluorouracil (5-FU) and its analogues: 1-(2-tetrahydrofuryl)-5-FU (FT), uracil/FT (UFT) and 1-hexylcarbamoyl-5-FU (HCFU), and the in vivo subrenal capsule (SRC) assay. The relative variation of tumor size (delta TS/TSo) was calculated as follows: delta TS/TS0 = (TS6-TS0/TS0) x 100%, where TS6 was the tumor size on day 6 and TS0 on day 0, and the chemosensitivity was considered to be sensitive when delta TS/TS0 in the treated group was decreased to below -10%. The mean tumor size was -10.9 +/- (SD) 10.9% for 5-FU, -12.3 +/- 17.1% for FT, -18.4 +/- 15.8% for UFT and -17.9 +/- 15.4% for HCFU. The decrease of tumor size was marked when exposed to UFT (p less than 0.01) or HCFU (p less than 0.02), compared with that to 5-FU. Positive correlations were noted between the tumor sizes of 5-FU and its analogues (5-FU vs. FT, r = 0.851; 5-FU vs. UFT, r = 0.746; 5-FU vs. HCFU, r = 0.685). In 9 tissues resistant to 5-FU, 2 (22%) were sensitive to FT, 4 (44%) to UFT, 5 (56%) to HCFU and 7 tissues (78%) to at least one of these analogues. These results suggest that the SRC assay is useful for predicting the effective drug among 5-FU and 5-FU analogues, for individual patients with cancer.     

Study on the concentrations of 5-fluorouracil (5-FU), tegafur (ET) and uracil in bile: comparison of UFT or FT

The serum and bile tegafur (FT), 5-fluorouracil (5-FU) and uracil levels after administration of UFT were assessed in 13 cases of malignant biliary tumor accompanied by biliary obstruction in comparison with FT alone. The serum and bile FT and 5-FU levels showed almost the same transition pattern in both groups, reaching to the plateau in 1-2 weeks and revealing cumulative effect by continual administration. Correlation was obtained between serum and bile levels except for 5-FU level in UFT group (p less than 0.05). Correlation between 5-FU and uracil was obtained in the serum in both groups (p less than 0.05), but no effect of uracil was observed. In bile, correlation was seen only in UFT group (p less than 0.05), and the effect of uracil was observed in bile 5-FU level.     

Hyperthermia enhances the inhibition of tumor growth by 1-(2-tetrahydrofuryl)-5-fluorouracil/uracil (1:4) in tumors in mice and humans.

The cytotoxicity of several antitumor drugs is enhanced by hyperthermia (HT). Using mouse Sarcoma-180 (S-180) tumors, the authors examined the effects of 5-fluorouracil (5-FU) and a combined oral preparation of 1-(2-tetrahydrofuryl)-5-fluorouracil (FT) and uracil in a molar ratio of 1:4 (UFT), in combination with HT. The antitumor effect of 5-FU was not enhanced significantly by HT. Growth inhibition by UFT plus HT was significantly greater than that by UFT alone, whereas inhibition by UFT alone was significantly greater than that by 5-FU. The intracellular metabolism of 5-FU and FT in whole homogenates of S-180 cells, human tumor cell lines (SC-2 and Lu-99), and five fresh human tumor tissues also was investigated. Conversion of FT to 5-FU, phosphorylation, and degradation of 5-FU were assayed with [3H]FT or [3H]5-FU, and the products were separated by thin-layer chromatography. The conversion of FT to 5-FU and the phosphorylation of 5-FU were more rapid at 43 degrees C than at 37 degrees C, whereas the degradation of 5-FU to 2-fluoro-beta-alanine remained unchanged. This acceleration of the active metabolism of FT and 5-FU may be one explanation for the enhanced effect of UFT by HT.     

5-fluorouracil concentration in gastroenterological tumor tissues, in adjacent normal tissues, and in serum after preoperative oral administration of 5'-deoxy-5-fluorouridine (5'-DFUR)

The 5-fluorouracil (5-FU)-concentration in resected tumor tissues was compared with that in the adjacent normal tissues or that in serum. Twenty-three patients with cancer of the digestive organs [(carcinoma of the stomach (12), colon (6), gallbladder (1), liver (1), ampulla of Vater (1), bile duct (1) and pancreas (1)] were administered orally 600-1, 200 mg/day of 5'-deoxy-5-fluorouridine (5'-DFUR) for 3 to 5 consecutive preoperative days. The average 5-FU-concentration in tumor tissues of 14 patients with 16 specimens measured 5 hours after final administration of 5'-DFUR was 62 ng/g. This level was significantly higher than that in adjacent normal tissues (21 ng/g, p less than 0.01). With 10 out of these 14 patients, the 5-FU-concentration in the serum was also measured. Among these 10 patients, the concentration of 5-FU in tumors (54 ng/g) was significantly higher than in adjacent normal tissues (19 ng/g) and in serum (12 ng/ml). At 6 to 9 hours after final administration, the mean concentration of 5-FU was 33 ng/g (n = 4) in tumor tissues, 30 ng/g (n = 5) in adjacent normal tissues and 24 ng/ml in serum. There was no significant difference among these mean values. For 4 patients whose specimens were taken at 17 to 18 hours after the last 5-FU administration, the mean concentration of 5-FU was 29 ng/g (n = 4) in tumor tissues, 14 ng/g (n = 3) in adjacent normal tissues and 4 ng/ml (n = 2) in serum.     

Effects of intravenous feeding on adjuvant chemotherapy--an experimental study on the distribution of 5-FU after injection of tegafur (1)

Forty-eight male Donryu rats inoculated with Sato lung cancer were used to experimentally determine the effects of intravenous feeding on the concentrations of the chemotherapeutic agents FT-207 and 5-FU in the blood, as well as in the liver and tumorigenic tissue. Following FT-207 administration, the blood, tumor and liver tissue levels were lower than in the IVH group (oral administration). The liver 5-FU concentration, at 0.10 +/- 0.02 microgram/g, was significantly higher in the intravenous feeding group than in the p.o. group (0.05 +/- 0.01 micrograms/g). The 5-FU blood concentration rose quickly, reaching 0.051 +/- 0.013 micrograms/ml and 0.035 +/- 0.004 micrograms/ml at 9 and 12 hours, respectively, following treatment. This was significantly higher than in the p.o. group, which showed corresponding levels of 0.031 +/- 0.004 microgram/ml and 0.022 +/- 0.002 microgram/ml, respectively. The increase in the 5-FU level within the tumor was markedly high in the IVH group compared to the p.o. group, and it peaked at 9 hours following administration. The concentration in the IVH group was thus higher than in the p.o. group at any given time. At 24 hours after treatment, the IVH group level was 0.35 +/- 0.09 microgram/g, against 0.27 +/- 0.05 microgram/g in the p.o. group. The blood concentration of 5-FU following intravenous feeding maintained a high value for a long time, and the 5-FU tumor concentration also remained at a high level. The intravenous route was therefore considered to be advantageous for antitumor chemotherapy.     

Randomised study of tegafur and oral leucovorin versus intravenous 5-fluorouracil and leucovorin in patients with advanced colorectal cancer

This randomised, open-label trial compared oral tegafur (FT)/leucovorin (LV) with the intravenous bolus 5-fluorouracil (5-FU)/LV as first-line chemotherapy for advanced colorectal cancer (CRC). Patients were randomised to receive oral FT 750 mg/m2/day for 21 days and LV 15 mg/m2 every 8 h in cycles repeated every 28 days (n=114), or intravenous LV 20 mg/m2 followed by 5-FU 425 mg/m2 daily for 5 days every 4 weeks for 2 cycles, and later every 5 weeks (n=123). Response rate was significantly higher in the FT/LV arm (27%, 95% CI 19-35) than in the 5-FU/LV arm (13%, 95% CI 7-19) (p<0.004). The median time to progression was 5.9 months (95% CI, 5.3-6.5; FT/LV arm) and 6.2 months (95% CI, 5.4-6.9; 5-FU/LV arm). Median overall survival was 12.4 months (95% CI, 10.3-14.5 months; FT/LV arm) and 12.2 months (95% CI, 8.9-15.7 months; 5-FU/LV arm) (p=n.s.; hazard ratio FT/LV:5-FU/LV=1.02). 5-FU/LV showed a higher incidence of grade 3/4 neutropenia (4.1 vs. 0%). Non-hematological toxicities showed similar incidences in the two treatment arms. Oral FT/LV was more active than IV 5-FU/LV in terms of objective response rate with similar overall survival, and with a favorable toxicity profile. This makes FT/LV a valid alternative to the IV 5-FU schedule in CRC patients.     

Pharmacokinetics of 5-fluorouracil following hepatic intra-arterial infusion in a VX2 hepatic metastasis model

BACKGROUND: Hepatic intra-arterial infusion chemotherapy of 5-fluorouracil (5-FU) or fluorodeoxyuridine (FUDR) has been a treatment option for liver metastasis from colorectal cancer. However, an optimal administration schedule of 5-FU is still controversial. This study was conducted to evaluate a suitable schedule from the viewpoint of 5-FU metabolites and related enzymes. METHODS: 5-FU was infused into the hepatic artery of rabbits having hepatic deposits of VX2 tumor cells in a daily dose of 1, 4, or 8 mg/kg using various schedules. 5-FU, Thymidylate synthase (TS), TS inhibition rate (TSIR), and the amount of fluoro-RNA (F-RNA) were measured. RESULTS: A high concentration of 5-FU was detected in the tumors of the group that was administered a dose of 8 mg/kg. TSIR in the tumor was about two-fold higher in the rabbits that were administered a total dose of 8 mg/kg than in those that were administered doses of 4 mg/kg or less. F-RNA, ranging from 27 to 36 ng/mg RNA, was detected in the tumor of the rabbits that were administered a total dose of 8 mg/kg. No difference was observed between the short period and the continuous administration schedules of rabbits that were administered a dose of 8 mg/kg of 5-FU. However, DNA synthesis inhibition in normal hepatic tissue was more dependent on the administration schedule than on the total dose of 5-FU because TSIR was significantly higher with shorter periods of drug administration. CONCLUSION: Intermittent bolus administration of large doses of 5-FU might cause more severe hepatic impairment than continuous administration. These results suggest that hepatic intra-arterial infusion of 5-FU should be administered continuously for liver metastasis, although further experiments including a longer administration period of 5-FU are required.     

Clinical trial of sequential N-phosphonacetyl-L-aspartate, thymidine, and 5-fluorouracil in advanced colorectal carcinoma

Preclinical studies have demonstrated enhanced cytotoxic effects of 5-fluorouracil (5-FU) when given in conjunction with N-phosphonacetyl-L-aspartate (PALA) or thymidine in several murine systems. Early clinical studies have demonstrated significant delayed depletion of pyrimidine nucleotides in tumor biopsy specimens following systemic PALA administration and prolonged serum levels of 5-FU after thymidine administration. Each of these biochemical effects would be anticipated to augment the cytotoxic activity of 5-FU. A phase II trial of a timed sequential administration schedule of PALA, thymidine, and 5-FU was conducted in 37 patients with advanced measurable colorectal cancer. Ten of 37 patients (27%) experienced objective tumor responses with a median response duration of 22 weeks, and 18 patients (49%) had stable disease for a median duration of 20 weeks. Six of 13 patients (46%) with anaplastic histology and/or rapidly progressive tumors experienced high-quality tumor responses. Leukopenia and neurologic side effects were the primary toxicities, including one death caused by sepsis. This regimen has demonstrated striking alteration in the 5-FU dose-effect relationship and definite antitumor activity in patients with advanced colorectal cancer. Further trials in patients with anaplastic carcinomas of the colon or other anatomic sites should be considered.     

1-hexylcarbamoyl-5-fluorouracil is more cytostatic than 5-fluorouracil against human tumors in vitro

The sensitivity of HeLa cells and 15 human tumors, including eight gastric cancers, five colorectal cancers and two lung cancers to 1-hexylcarbamoyl-5-fluorouracil (HCFU) was compared with that to 5-fluorouracil (5-FU) in vitro. HeLa cells were doubly sensitive to HCFU, as compared to 5-FU. After the HeLa cells had been treated with 5-FU or HCFU at 77 μM for 1–5 h, the intracellular levels of 5-FU and HCFU were determined, using gas chromatographic-mass spectrometric methods. The level of HCFU plus 5-FU in the HCFU-treated cells was twice as high as the level of 5-FU in the 5-FU-treated cells. The sensitivity to HCFU in 15 tumor tissues varied with the tissue; however, all tissues tested were more sensitive to HCFU than to 5-FU, assessed using the succinate dehydrogenase inhibition test. These results suggest that the hexylcarbamoyl structure facilitates the rapid uptake of HCFU through the cell membrane. HCFU may prove to be more effective for treating each individual patient with a malignant lesion.     

Bioavailability of subcutaneous 5-fluorouracil: a case report

 The optimal schedule for the administration of 5-fluorouracil (5-FU) in the management of advanced colorectal cancer remains to be determined. It has been suggested that this drug may be given by the subcutaneous route and that following a short infusion the bioavailability is similar to that observed after intravenous administration. We report the results we obtained in a patient treated with an intravenous bolus of 5-FU followed by a 22-h subcutaneous infusion. In this patient the bioavailability of 5-FU given by subcutaneous infusion was 0.94. The steady-state plasma levels of 5-FU reached during subcutaneous infusion were comparable with those achieved during intravenous infusion. Following four cycles of subcutaneous therapy, painless blistering was noted at the infusion sites, which healed following the cessation of subcutaneous therapy. Further studies are required to evaluate this route of therapy as an alternative to protracted intravenous therapy. The main dose-limiting side effect appears to be local skin toxicity. Received: 27 August 1995 / Accepted: 16 November 1995     

Long-term ambulatory treatment of metastatic colorectal adenocarcinoma by continuous intravenous infusion of 5-fluorouracil

To delineate the efficacy of continuous intravenous 5-fluorouracil (5-FU) infusion therapy for advanced colorectal adenocarcinoma, a study of 36 patients with measurable metastatic disease was conducted. Patients received a daily intravenous infusion of 300 mg/m2 5-FU over a 24-h period utilizing portable infusion devices and central venous catheters. In a population characterized by substantial pretreatment exposure to radiotherapy, chemotherapy, and other indicators of poor prognosis, 13/36 (36%) patients achieved an objective response. An additional 10/36 (28%) patients manifested stable disease (no change) and experienced survival comparable to that of patients with objective response. Toxicity was minimal; patients were able to continue 5-FU infusions 95% of the total time on protocol. There were no adverse hematologic effects or catheter complications. Because previously untreated patients benefited more frequently (positive response, 50%), continuous intravenous infusion should be evaluated further as a primary modality option when 5-fluorouracil antitumor chemotherapy is contemplated.     

A phase III study of 5-fluorouracil versus 5-fluorouracil plus interferon alpha 2b versus 5-fluorouracil plus leucovorin in patients with advanced colorectal cancer: a Hellenic Cooperative Oncology Group (HeCOG) study

We conducted a phase III study in patients with advanced colorectal carcinoma (ACC). The total number of patients randomized from October 1993 until July 1998 was 192, whereas therapy was started on 179 and 158 (82.3%) have been evaluable. The treatment schedules consisted of weekly bolus administration for 6 weeks of 5-fluorouracil (5-FU), 600 mg/m2 (arm I) versus 5-FU (500 mg/m2) intravenous bolus and interferon-alpha, 5 MU subcutaneously, three times a week (arm II) versus leucovorin 200 mg/m2 in 2-hour infusion and 5-FU 500 mg/m2 intravenous bolus at the midtime of leucovorin infusion (arm III) followed by a 2-week rest period. Treatment was continued for six cycles or until progression. This study failed to show any superiority of the modulated 5-FU versus single administration of 5-FU. There were no significant differences between the three arms in the overall response rate (10.3% versus 11.3% versus 12.9%, p = 0.95), the time to tumor progression (median, 3.9 versus 3.8 versus 6.0 months, p = 0.59), or survival duration (median, 14.7 versus 12.4 versus 16.3 months, p = 0.71). The incidence of severe (grades III and IV) toxicity was significantly higher in patients in arm II and III (24.5% and 18.6%) versus arm I (6.0%) (p = 0.01). Because modulated 5-FU failed to show superiority versus 5-FU, new agents and new strategies are needed for the treatment of advanced colorectal carcinoma.     

Investigation of 5-fluorouracil (5-FU) levels and pyrimidine nucleoside phosphorylase activities in the tissues from patients with uterine cervical and ovarian cancers after oral administration of 5'-DFUR]

The usefulness of 5'-DFUR in both patients with uterine cervical and ovarian cancers was investigated by determining pyrimidine nucleoside phosphorylase (PyNPase) activities and 5-FU levels in cancerous and normal tissues resected from them after oral administration of 5'-DFUR. In uterine cervical cancer, each group of 9 cases administered single dose of 400 mg of 5'-DFUR and 7 cases administered 400 mg of 5'-DFUR 3 times a day continuously for 7 days was investigated. In ovarian cancer, all of 9 cases were administered 400 mg of 5'-DFUR 3 times a day continuously for 7 days. In conclusion, PyNPase activities in the tissues of uterine cervical and ovarian cancers were higher than those in the normal tissues. 5-FU tissue levels in the cancerous tissues were significantly higher than in the normal tissues and blood as well. This tendency was observed in each of the single and continuous administration groups. These results suggest that the tumor selectivity which is one of characteristics of 5'-DFUR could be expected also for cancer in the field of gynecology.     

Concentration of 5-fluorouracil in the blood and tissues of gastric and colo-rectal cancer patients after oral administration of UFT]

UFT is given to the patients with digestive cancer from the time before operation to prevent intra- and post-operative cancer dissemination and metastases. UFT (400 mg/day in terms of tegafur) was given preoperatively for 1-6 days in 6 patients with gastric cancer and 13 with colorectal cancer. The interval between the last administration and the beginning of the operation was 3.9 +/- 1.5 hours (mean +/- SD). The concentrations of tegafur, 5-FU, and uracil in the blood collected at the time of tumor resection were 9.68, 0.017, and 0.08 microgram/ml, respectively. In the patients with gastric cancer 5-FU concentration was 5.5 times higher in the normal mucosa, 3.3 times in lymph nodes, and 10.7 times in the tumor tissues than in the blood. In colorectal cancer patients, also, the 5-FU concentration was 5.6, 8.3 and 20.8 times higher in the normal mucosa, lymph nodes, and the tumor tissue, respectively, than in the blood. The 5-FU concentration in gastric cancer and colorectal cancer tissues decreased with time after administration of UFT but remained above the effective concentration 1.5-7 hours after administration of 200 mg. The tissue concentrations of FT-207, uracil, and 5-FU were correlated with each other.     

Effects of the plasma concentration of 5-fluorouracil and the duration of continuous venous infusion of 5-fluorouracil with an inhibitor of 5-fluorouracil degradation on Yoshida sarcomas in rats

The correlations of the 5-fluorouracil (5-FU) level in the plasma and the duration of continuous 5-FU infusion with the antitumor activity of 5-FU on Yoshida sarcomas in rats were examined. The circadian variation in the plasma level of 5-FU during continuous infusion was prevented by treatment with 3-cyano-2,6-dihydroxypyridine (CNDP), which strongly inhibits 5-FU degradation. On continuous venous infusion of 2 to 30 mg/kg of 5-FU over 24 h with CNDP at a molar ratio of 1:10 into normal rats, the 5-FU level in the blood was linearly proportional to the dose of 5-FU. The optimum schedule for antitumor activity on Yoshida sarcomas in rats was found to be infusion of 5-FU at 5 mg/kg over 24 h for 6 consecutive days, which gave a plasma 5-FU level of 176 ng/ml. Continuous infusion of 5-FU to give a plasma level of 300 ng/ml for 6 consecutive days from day 5 after implantation of tumor cells, when the tumors weighed about 1.0 g, resulted in complete regression of the tumors in all rats.     

Combination of levofolinate calcium and 5-fluorouracil

It has been determined that in the combination of Leucovorin (LV) and 5-fluorouracil (5-FU), LV potentiates the cytotoxic effect of 5-FU based on biochemical modulation. Many data suggest that LV/5-FU is a very effective combination, and most clinicians worldwide now regard it as the standard therapy for colorectal cancer. In Japan, clinical examinations of this combination using Levofolinate calcium (I-LV) have shown its effectiveness, and I-LV/5-FU for gastric and colorectal cancer was authorized by the Ministry of Public Welfare in Oct. 1999.     

Experimental studies on the optimal therapeutic mode of intra-arterial infusion of 5-fluorouracil. (2) Concentrations within the tumors and normal tissues and therapeutic and adverse effects of 5-fluorouracil delivered by various routes

5-Fluorouracil levels in Yoshida sarcoma implanted subcutaneously and some organs of rats were measured following intraarterial or intravenous administration of 5-FU at various infusion time and doses, and the relationship between 5-FU level in tumors and antitumor effect was examined. The antitumor effect following intraarterial infusion of 5-FU was superior to its systemic administration. With intraarterial infusion, higher levels of 5-FU in tumors could be expected during infusion and immediately after injection. One-shot intraarterial injection of 5-FU was much more effective than continuous infusion of 5-FU from view points of the antitumor effect. This reason might be attributed to that, 5-FU level in the tumor after one shot intraarterial injection was maintained higher for many longer period than its level during continuous infusion. 5-FU levels in the liver following and during intraaortic infusion of 5-FU showed interesting change, i.e. if 5-FU levels flowing into the liver was low, 5-FU in the liver was not detected at all, however, if high level of 5-FU was flown into, the liver 5-FU was measured even 24 hours after injection. It was supposed that the low level of 5-FU was degraded by the liver easily, but the high level of 5-FU flown into the liver could not be metabolized. From these experiments it may be concluded that infusion time of intraarterial administration of 5-FU must be as short as possible within tolerable toxicity, and infusion doses must be as high as possible that could be degraded by the liver for reduction of toxicity.