Metabolic basis of the synergistic antitumor activities of 5-fluorouracil and cisplatin in rodent tumor models in vivo

Phase I/II study of S-1 combined with carboplatin in recurrent and/or metastatic head and neck cancer as outpatient chemotherapy

BACKGROUND

The aims of this study were to determine the recommended dose (RD) in combination chemotherapy of S-1 and carboplatin in recurrent and/or metastatic head and neck cancer (phase I) and to examine response rate and toxicities at RD (phase II).

METHODS

S-1 was given orally at a fixed dose of 40, 50, or 60 mg twice daily based on the patient's body surface area for 21 days followed by a 14-day rest. In phase I, carboplatin was given intravenously to a cohort of three patients on day 8 at a dose of 2.5, 3.0, 3.5, or 4.0 area under the curve (AUC) values, depending on the dose-limiting toxicities (DLTs).

RESULTS

In phase I, the RD was estimated as 2.5 AUC. In phase II, thrombocytopenia and leukopenia were most commonly found as hematologic DLTs, which were manageable without hospitalization. The response rate was 40.9%.

CONCLUSIONS

This regimen is considered to be active against recurrent and/or metastatic head and neck cancer in an outpatient setting.

Performance of outpatient regimen of S-1 in combination with fractional cisplatin for advanced or recurrent gastric cancers: a phase I study

BACKGROUND

We designed an outpatient regimen consisting of fractional cisplatin in combination with S-1, a novel oral fluoropyrimidine derivative for the treatment of recurrent or advanced gastric cancer and conducted a phase I study to determine the dose limiting toxicities (DLTs) and recommended dose (RD).

METHODS

Escalating dosages of cisplatin (15, 20, and 25 mg/m(2), as levels 1, 2, and 3, respectively) were administered over 2 h on days 1, 8, and 15, with a fixed dose of S-1 for 3 consecutive weeks (days 1-21), repeated every 5 weeks. National Cancer Institute common toxicity criteria(NCI-CTC) grade 2 toxicities required treatment delay. Primary first cycle DLTs were defined as NCI-CTC grade 3 or 4 toxicities (except for hemoglobin levels, nausea, and vomiting).

RESULTS

Nine patients were initially enrolled, and DLTs did not appear; however, one level-3 patient experienced grade 3 anemia. An additional three patients were enrolled in level 3 to confirm the toxicity profiles, and none experienced DLTs. Toxicity evaluations throughout a total of 62 cycles revealed that grade 1 or 2 hematological toxicities were common, although mostly transient, with recovery without specific treatment. One patient each in levels 1 and 3 required hospitalization due to grade 3 toxicities in the later cycles. Mean dose intensities for S-1 and cisplatin were both more than 91%. There were no treatment-related deaths. The preliminary response rate was 44%.

CONCLUSIONS

It was concluded that the RD of cisplatin in this regimen was 25 mg/m(2) (level 3). S-1 in combination with fractional cisplatin is a promising regimen that allows repeated drug administration, in an outpatient setting, for advanced or recurrent gastric cancers. A phase II study of the RD is now under way.

Cellular processing of platinum anticancer drugs

Cisplatin, carboplatin and oxaliplatin are platinum-based drugs that are widely used in cancer chemotherapy. Platinum-DNA adducts, which are formed following uptake of the drug into the nucleus of cells, activate several cellular processes that mediate the cytotoxicity of these platinum drugs. This review focuses on recently discovered cellular pathways that are activated in response to cisplatin, including those involved in regulating drug uptake, the signalling of DNA damage, cell-cycle checkpoints and arrest, DNA repair and cell death. Such knowledge of the cellular processing of cisplatin adducts with DNA provides valuable clues for the rational design of more efficient platinum-based drugs as well as the development of new therapeutic strategies.

S-1 plus cisplatin combination chemotherapy in patients with advanced non-small cell lung cancer: a multi-institutional phase II trial

PURPOSE

To evaluate the efficacy and toxicity of a novel combination chemotherapeutic regimen including cisplatin with an oral anticancer agent, S-1 that consisted of tegafur, 5-chloro-2, 4-dihydroxypyridine, and potassium oxonate, for non-small-cell lung cancer (NSCLC) patients.

EXPERIMENTAL DESIGN

In this phase II trial, patients with locally advanced and metastatic NSCLC were treated with the oral administration of S-1 at 40 mg/m(2) twice a day for 21 consecutive days while cisplatin (60 mg/m(2)) was administered intravenously on day 8. This schedule was repeated every 5 weeks.

RESULTS

Of 56 patients enrolled in the study, 55 patients were eligible and analyzed. The median number of cycles administered was 3 (range, 1-12 cycles). Among these 55 patients, one complete response and 25 partial responses were observed with an overall response rate of 47% (95% confidence interval, 34-61%). The median survival time was 11 months and the 1-year survival rate was 45%. Hematologic toxicities of grades 3 and 4 included neutropenia (29%) and anemia (22%). No grade 4 nonhematologic toxicity was observed. Grade 3 toxicity included anorexia (13%), vomiting (7%), or diarrhea (7%).

CONCLUSIONS

S-1 plus cisplatin combination chemotherapy showed a promising effectiveness with acceptable toxicity rates in patients with advanced NSCLC. These results warrant further investigations of this regimen including a randomized controlled trial for its use as a first line treatment for NSCLC.

Does cisplatin (CDDP) function as a modulator of 5-fluorouracil (5-FU) antitumor action? A study based on a clinical trial

OBJECTIVE

To clarify whether CDDP acts as a modulator of 5-FU antitumor action in gastric cancer, patients were treated preoperatively with 5-FU + CDDP (FP) chemotherapy.

PATIENTS AND METHODS

From September 2000 to November 2001 at Takarazuka Municipal Hospital, 29 patients preoperatively diagnosed with stages II-IV gastric cancer were enrolled. Written informed consent was obtained from all patients. The patients were randomly assigned to two groups: the FU group, in which patients received a continuous intravenous infusion of 5-FU 320 mg/m2 per day over 24 h a day for 5 days beginning 5 days prior to surgery, and the FP group, in which patients received bolus intravenous injections of CDDP 3.5 mg/m2 per day for 5 days prior to surgery in addition to the same infusion of 5-FU as the FU group. As indicators of the intracellular effect of 5-FU treatment, thymidylate synthase (TS) inhibition rates, TS protein levels, TS and dihydropyrimidine dehydrogenase (DPD) activity, and F-RNA concentrations were measured.

RESULTS

Using Scheffe's multiple comparison test, in both treatment groups the tumor regions were found to have significantly higher TS inhibition rates than the nontumor regions (P<0.05). No significant differences in TS protein levels, TS activity, DPD activity or F-RNA concentrations were found between the four regions.

CONCLUSIONS

Our results show that CDDP clinically may act to enhance the antitumor effects of 5-FU in terms of the inhibition of DNA synthesis and could therefore act as a modulator of 5-FU.

Pharmacokinetic study of oxaliplatin iv chronomodulated infusion combined with 5-fluorouracil iv continuous infusion in the treatment of advanced colorectal cancer

We investigated the pharmacokinetics (PK), preliminary clinical results and toxicity of chronomodulated oxaliplatin (OHP) plus 5-fluorouracil (5-FU) without folinic acid (FA) in 13 patients with metastatic colorectal cancer. 5-FU (200 mg/m2/day as 14-day continuous iv infusion for six cycles) plus OHP at increasing doses (25-30-35 mg/m2/day, as 12 h chronomodulated iv infusion on days 1-2-3-4, every 14 days for six cycles) were administered to reach maximum tolerated dose (MTD). At MTD (30 mg/m2/day), a PK study of 5-FU and OHP (in total and ultrafiltered-UF plasma) was performed. 5-FU plasma levels were fairly stable, below that reported in similar studies and closely related to the lack of the most typical 5-FU toxicities. OHP Cmax occurred 7 h after infusion start; a progressive accumulation of free Pt and ultrafiltered Pt (UF-OHP) through cycles 1-6 was noted. A marked difference between total plasma and UF Pt was seen in the elimination phase. OHP plasma clearance decrease was related to Vz (volume of distribution of late elimination phase), whereas in UF-OHP was due to a change in Ke or t1/2. In conclusion, the association of 5-FU with chronomodulated OHP do not seem to influence PK parameters of either drugs. Toxicity was modest/acceptable and clinical efficacy good: preliminary data showed a threshold neurotoxicity at total plasma Pt concentrations >1500 ng/ml and UF plasma Pt concentrations >150 ng/ml.

Trial of low-dose 5-fluorouracil/cisplatin therapy for advanced extramammary Paget's disease

BACKGROUND

An effective chemotherapy for advanced extramammary Paget's disease has not yet been established. Recently, a low dose 5-fluorouracil/cisplatin (FP) regimen has been reported to be effective for adenocarcinoma, including gastric and colon carcinoma. However, this chemotherapeutic option has not been evaluated as to its effectiveness for extramammary Paget's disease.

OBJECTIVE

We evaluated chemotherapy in a patient with advanced extramammary Paget's disease of the male genitalia unassociated with an underlying malignancy.

METHODS

In order to treat a patient with extramammary Paget's disease who had multiple metastases, 500 mg/day of 5-fluorouracil (7 days per week) and 5 mg/day of cisplatin (5 days per week) were administrated intravenously for 24 hours and 1 hour, respectively. This protocol was continued for 6 weeks.

RESULTS

A partial response was observed in both primary disease and metastatic disease. The primary tumor resolved almost entirely, leaving only a scar. Computed tomography scan revealed liver metastases that appeared to change into necrotic tissue; the metastases in lymph nodes and adrenal glands were markedly decreased and hardly detectable. In addition, the carcinoembryonic antigen level, a useful tumor marker for extramammary Paget's disease, decreased remarkably. It is suggested that this patient's survival period could have been prolonged. Serious side effects were not observed during this treatment.

CONCLUSION

In one patient with extramammary Paget's disease and multiple metastases, low-dose FP therapy appeared to be beneficial. This regimen may be effective for extramammary Paget's disease with systemic nodular metastasis as an adjuvant therapy combined with surgery.

Phase I/II study of S-1 combined with cisplatin in patients with advanced gastric cancer

A dose-escalation study of cisplatin (CDDP) combined with S-1, a new oral dihydropyrimidine dehydrogenase inhibitory fluoropyrimidine, was performed to determine the maximum-tolerated dose (MTD), recommended dose (RD), dose-limiting toxicities (DLTs), and objective response rate (RR) in advanced gastric cancer (AGC). S-1 was given orally at 40 mg m⁻² b.i.d. for 21 consecutive days following a 2-week rest. CDDP was planned to be given intravenously on day 8, at a dose of 60, 70, or 80 mg m⁻² depending on the DLT. Treatment was repeated every 5 weeks, unless disease progression was observed. In the phase I portion, the MTD of CDDP was presumed to be 70 mg m⁻², because 33.3% of patients (2/6) developed DLTs, mainly neutropenia. Therefore, the RD of CDDP was estimated as 60 mg m⁻². In the phase II portion, 19 patients including six patients of the RD phase I portion were evaluated. The median administered courses was four (range: 1–8). The incidences of severe (grades 3–4) haematological and nonhaematological toxicities were 15.8 and 26.3%, respectively, but all were manageable. The RR was 74% (14/19, 95% confidence interval: 54.9−90.6%), and the median survival day was 383. This regimen is considered to be active against AGC with acceptable toxicity.

Combination Phase I Trial of a Novel Oral Fluorouracil Derivative S-1 with Low-Dose Cisplatin for Unresectable and Recurrent Gastric Cancer (JFMC27–9902)

PURPOSE

The Japanese Foundation for Multidisciplinary Treatment of Cancer conducted a Phase I study of a novel oral fluorouracil derivative, S-1, combined with a low dose of cisplatin in unresectable and recurrent gastric cancer.

EXPERIMENTAL DESIGN

S-1 was administered orally at 80-120 mg/body/day, depending on body surface area. One course consisted of consecutive administration for 28 days followed by a rest of 14 days. Low-dose cisplatin was given i.v. on days 1-5, 8-12, 15-19, and 22-26 of each course. The dose escalation of cisplatin began with an initial dose of 1 mg/m(2)/day as level 1 and was stepped up to 2, 3, 4, and 6 mg/m(2)/day as level 2, 3, 4, and 5, respectively. The regimen was repeated for at least two courses.

RESULTS

A total of 24 patients was entered in the study. There was no treatment-related death. At level 5, consisting of 5 evaluable patients, dose-limiting toxicity was experienced as grade 3 appetite loss in 2 patients and grade 4 neutropenia in 1 patient. The maximum-tolerated dose of cisplatin was estimated to be 6 mg/m(2)/day. We decided on a recommended dose of cisplatin of 4 mg/m(2)/day because the dosage was one level under the maximum-tolerated dose. All 3 patients at level 4 showed partial response, suggesting promising clinical efficacy with this dosage. The serum concentration of cisplatin at level 4 was 918 +/- 92 ng/ml on day 26 of the first course.

CONCLUSIONS

S-1 with low-dose cisplatin may become an effective regimen with acceptable toxicity for gastric cancer.

Hepatic arterial infusion chemotherapy for hepatocellular carcinoma with tumor thrombosis of the portal vein tumor thrombosis

AIM: Hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is associated with poor prognosis. The aim of this prospective study was to evaluate the efficacy of hepatic arterial infusion chemotherapy (HAIC) for patients with this disease.

METHODS: Eighteen HCC patients with PVTT were treated with HAIC via a subcutaneously implanted injection port. A course of chemotherapy consisted of daily cisplatin (10 mg for one hour) followed by 5-fluorouracil (250 mg for five hours) for five continuous days within a given week. The patients were scheduled to receive four consecutive courses of HAIC. Responders were defined in whom either a complete or partial response was achieved, while non-responders were defined based on stable or progressive disease status. The prognostic factors associated with survival after treatment were analyzed.

RESULTS: Six patients exhibited partial response to this form of HAIC (response rate = 33%). The 3, 6, 9, 12 and 18-month cumulative survival rates for the 18 patients were 83%, 72%, 50%, 28%, and 7%, respectively. Median survival times for the six responders and 12 non-responders were 15.0 (range, 11-18) and 7.5 (range, 1-13) months, respectively. It was demonstrated by both univariate and multivariate analyses that the therapeutic response and hepatic reserve function were significant prognostic factors.

CONCLUSION: HAIC using low-dose cisplatin and 5-fluorouracil may be a useful alternative for the treatment of patients with advanced HCC complicated with PVTT. There may also be survival-related benefits associated with HAIC.

Mechanism of cell death induced by the novel enzyme-prodrug combination, nitroreductase/CB1954, and identification of synergism with 5-fluorouracil

Virus-directed enzyme prodrug therapy (VDEPT) utilising the bacterial enzyme nitroreductase delivered by a replication-defective adenovirus vector to activate the prodrug CB1954 is a promising strategy currently undergoing clinical trials in patients with a range of cancers. An understanding of the mechanism of tumour cell death induced by activated CB1954 will facilitate this clinical development. Here, we report that activated CB1954 kills cells predominantly by caspase-dependent apoptosis. This may have important implications for the generation of immune-mediated bystander effects. Further, the use of a replication-defective adenovirus vector to deliver nitroreductase may negatively affect cellular apoptotic pathways stimulated by activated CB1954. Finally, examination of nitroreductase/CB1954 in combination with conventional chemotherapy reveals a synergistic interaction with 5-fluorouracil. These data will facilitate the further development and future clinical trial design of this novel therapy.

Effect of combination of TS-1 and low-dose cisplatin on sarcoma-180 mouse sarcoma

TS-1 contains tegaful (FT), 5-chloro-2,4-dihydroxypyridine (CDHP; an inhibitor of 5-fluorouracil (5-FU) degradation) and potassium oxonate (Oxo; an inhibitor of 5-FU assimilation mainly in the digestive tract) in a molar ratio of 1:0.4:1. We evaluated the combination of TS-1 and low-dose cisplatin on mouse sarcoma. Male ddy strain mice at 6 weeks of age were s.c. transplanted with 5 x 106 sarcoma-180 (S-1800) cells and divided into groups of seven animals each: Group A, no treatment; Group B, 5-FU alone by continuous i.p. infusion of 10 mg/kg with a minipump (Alzet); Group C, TS-1 10 mg/kg p.o. alone; Group D, cisplatin 0.2 mg/kg i.p. alone; Group E, B+D; Group F, C+D. Treatment was given for 5 days. Antitumor activity was evaluated on the basis of the tumor weight on day 8, and white blood cell count, red blood cell count, platelet count, BUN, GOT and GPT were determined to detect adverse effects. Tumor weights (g, mean+/-SD) were 0.54+/-0.15 in Group A, 0.52+/-0.17 in Group B, 0.34+/-0.05 in Group C, 0.46+/-0.12 in Group D, 0.34+/-0.07 in Group E and 0.16+/-0.03 in Group F. There were no noticeable adverse effects. The combined TS-1+cisplatin regimen showed considerably enhanced antitumor activities since sarcomas were significantly (p<0.05) decreased as compared with tissue. Mean AUC(0-12) (ng/ml.h) estimated in the groups receiving 5-FU+cisplatin or TS-1 alone was measured to calculate AUC(0-12) by the trapezoidal rule. 5-FU concentrations in blood and tumor from blood concentration data were 435 in Group B, 2651 in Group C, 343 in Group E and 1538 in Group F, while mean AUC(0-12) (ng/g.h) estimated from tumor tissue concentration data were 345 in Group B, 3548 in Group C, 324 in Group E and 2020 in Group F. Cisplatin acted as a modulator of 5-FU, suggesting clinical benefits of the combination of TS-1 and low-dose daily cisplatin.

Phase I study of combination chemotherapy with 5-fluorouracil (5-FU) and nedaplatin (NDP): adverse effects and eecommended dose of NDP administered after 5-FU

When nedaplatin (NDP) was used as a single agent in the phase I study, the dose-limiting toxicity (DLT) was thrombocytopenia and the recommended dose (RD) was 100 mg/m2. However, the DLT, maximum tolerated dose (MTD) and RD of NDP used in combination with 5-fluorouracil remained unknown. Therefore, we performed this study to assess the DLT and RD of NDP administered after 5-fluorouracil (5-FU). In this study, 5-FU was administered to 38 patients at a fixed dose (700 mg/m2/d on days 1-5) and NDP administered on day 6 at an initial dose of 80 mg/m2, which was subsequently increased to 100, 120, 130, 140, 150, and 160 mg/m2. The DLT of NDP was leukopenia and its MTD and RD were 160 and 150 mg/m2, respectively. Concerning impairment of renal function, only two patients had a grade I increase in serum creatinine. There were 19 responders (50%, 19/38) achieving partial response or complete response in the evaluation of antitumor effect. The result of this study is notable in that administration of 5-FU before NDP allows the dose of NDP to be substantially increased.

Hepatic arterial infusion of 5-fluorouracil and cisplatin for unresectable or recurrent hepatocellular carcinoma with tumor thrombus of the portal vein

BACKGROUND AND OBJECTIVES

This study was designed to evaluate the efficacy of hepatic arterial infusion of 5-fluorouracil (5-FU) and cisplatin (CDDP) for unresectable or recurrent hepatocellular carcinoma (HCC) with tumor thrombus of the trunk or first branches of the portal vein (PVTT).

METHODS

Seven unresectable or recurrent HCC patients with PVTT were enrolled in this study. A one-week course of chemotherapy consisted of intraarterial administration of CDDP (10 mg on days 1-5) for 1 h and 5-FU (250 mg on days 1-5) for 24 h, followed by cessation of administration for the subsequent 2 days (days 6 and 7). Three or more sequential courses of chemotherapy were given through an implanted reservoir.

RESULTS

Serum alpha-fetoprotein (AFP) levels before the chemotherapy were >20 ng/ml in six of the seven patients. Serum AFP levels were decreased in four of the six patients after chemotherapy, including two patients (cases 1 and 7) whose AFP levels later returned to normal. Six of the seven patients had measurable lesions in the liver, with a response rate of 33%. In three of the seven patients (43%), PVTTs decreased in size or disappeared after chemotherapy. The mean and median survival periods of all patients were 8.0 and. 7.5 months, respectively.

CONCLUSIONS

The chemotherapy described in this report is beneficial in terms of survival for HCC patients with PVTT for whom transcatheter arterial embolization or surgical treatment is contraindicated.

Continuous infusion low-dose CDDP/5-FU plus radiation in inoperable or recurrent non-small-cell lung cancer: preliminary experience

The combination therapy of continuous infusion low-dose cisplatin plus 5-fluorouracil (5-FU) with radiation for non-small-cell lung cancer (NSCLC) was performed to assess its effectiveness and any adverse reactions. During the period from April 1994 to December 1998, 18 patients with inoperable or recurrent NSCLC at Aichi Cancer Center Hospital had been treated by chemoradiation with continuous infusion of low-dose cisplatin/5-FU. The median total radiation dose was 66 Gy (range: 60-74.4 Gy). The daily doses of cisplatin and 5-FU ranged from 3 to 6 mg/m2, and from 170 to 250 mg/m2, respectively. In 18 total patients, a complete response was achieved in 4 patients (22%), and a partial response was observed in 12 patients (67%). Grade III toxicity was limited to leukopenia (14.3%). The 1-year and 2-year survival rate in 14 previously untreated patients were 77.4% and 53.1%, respectively. This combination therapy is a well-tolerated regimen. In the future, a study protocol should be designed with a dose-escalation component to further define the optimal doses and schedule for this regimen.

Dihydropyrimidine dehydrogenase-related enzymes predict efficacy and adverse reactions of UFT1+cisplatin neoadjuvant chemotherapy for gastric cancer

Dihydropyrimidine dehydrogenase (DPD) and dihydropyrimidinase (DHP) are metabolic enzymes of fluoropyrimidine. UFT containing uracil (U) and Tegafur is the first reported DPD-inhibitory fluoropyrimidine. To clarify the significance of the enzyme activities, we examined the relationships between the effects and adverse reactions, and DPD and DHP activities in gastric cancer treated with UFT1+cisplatin neoadjuvant chemotherapy. Twenty-five gastric cancer patients were administered UFT at 370 mg/m(2)/day for 21 days and cisplatin at 15 mg/m(2)/day for 2 days. Dihydrouracil (DU) and U levels in the urine and DPD activities in the resected tumors were measured. Chemotherapeutic effects were classified histologically into non-responder and responder groups. The responder group accounted for 48% of the patients. All six patients with high DPD activities (> or = 0.08 nmol/min/ww) belonged to the non-responder group and 11 of 19 patients with low DPD activities (<0.08 nmol/min/ww) belonged to the responder group; the difference was significant (p=0.0435). Adverse reactions to UFT occurred in four patients, all of whom were among the six patients with abnormal DU/U values. The incidence of UFT adverse reactions was estimated at 67%. In conclusion, the measured levels of DPD-related enzyme activities appear to be significant for predicting the effects and adverse reactions to chemotherapy.

Protracted hepatic arterial infusion with low-dose cisplatin plus 5-fluorouracil for unresectable liver metastases from colorectal cancer

BACKGROUND

Hepatic arterial infusion (HAI) chemotherapy is a treatment option for unresectable liver metastases from colorectal cancer, but it is not yet a standard treatment. The aims of this study were to demonstrate the efficacy of protracted HAI chemotherapy with low-dose cisplatin plus 5-fluorouracil for patients with unresectable liver metastases from colorectal cancer.

METHODS

Twenty-two patients with unresectable liver metastases from colorectal cancer were treated with continuous HAI of 300 mg/m2 5-fluorouracil for 5 days a week and 6 mg/m2 cisplatin for 2 hours on 5 consecutive days a week. The plasma concentrations of cisplatin and 5-fluorouracil during the treatment were measured for a pharmacokinetic study.

RESULTS

Of the 22 patients, 2 had a complete response, 13 had a partial response, 6 had stable disease, and 1 had progressive disease, and the response rate was 68% (15/22). The median survival time was 17 months, and 1-, 2-, and 3-year survival rates were 59%, 26%, and 13%, respectively. Progressive disease was the reason for treatment discontinuation in 10 (45%) of the 22 patients, and 9 (41%) patients had to stop the treatment because of complications. Systemic toxicity was minimal. The pharmacokinetic study showed a high degree of hepatic extraction for both cisplatin and 5-fluorouracil during the treatment.

CONCLUSIONS

The treatment regimen described herein thus appears to be efficacious regarding the tumor response and survival for patients with unresectable liver metastases from colorectal cancer.

Schedule-dependent combined sensitivity testing of anti-cancer agents in human gastric carcinoma cell lines

The efficacy of combination chemotherapy for gastric carcinoma has been unsatisfactory, although the prognosis of advanced and recurrent disease has improved with the introduction of cisplatin (CDDP). This study examines the effect of the anti-cancer therapies CDDP, doxorubicin (ADM) and etoposide (VP-16) on the cell cycle and their cytotoxicity against two gastric carcinoma cell lines: MKN-28 (well differentiated) and MKN-45 (poorly differentiated). The treatments have different cytocidal mechanisms, and they were studied in dual combinations. For all combinations studied, cytotoxicity against MKN-45 was higher than against MKN-28. For ADM plus CDDP, or ADM plus VP-16, cytotoxicity was higher in patients pretreated with ADM than other regimens. The highest anti-tumour activity against both cell lines was obtained with ADM followed by CDDP (we have obtained good clinical results with this regimen). Schedule-dependent combined sensitivity testing of anti-cancer agents will be useful for the clinical application of therapies.

Carcinoma of an unknown primary site: a chemotherapy strategy based on histological differentiation--results of a prospective study

BACKGROUND

To evaluate the efficacy and toxicity of a chemotherapy strategy based on histological differentiation, for patients with carcinoma of unknown primary site.

PATIENTS AND METHODS

Forty-eight patients were prospectively included in the trial. Thirty patients with poorly-differentiated carcinoma or poorly-differentiated adenocarcinoma (group A) received a combination of cisplatin and etoposide. Patients with a responsive or stable disease after two cycles received the same regimen plus bleomycin, ifosfamide and G-CSF. Eighteen patients with well- or moderately-differentiated carcinoma (group B) received cisplatin, continuous infusion 5-fluorouracil (5-FU) and alpha-interferon. Treatment was maintained in case of response or stable disease for up to six cycles.

RESULTS

The overall response rate (RR) for the entire group is 43% (95% confidence interval (CI): 35.9%-50.1%): seven CR and five PR in group A (RR = 40%) and six CR and two PR in group B (RR = 44%). Grade 4 leucopenia was observed in 22 (46%) patients and sepsis in 3 (6%). Median survival is 9.4 months (range 5-13.7 months) and 16.1 months (range 11.8 20.3 months), respectively.

CONCLUSIONS

This chemotherapy strategy is one way to achieve high response rates, particularly for patients with well- or moderately-differentiated adenocarcinoma usually considered poorly chemosensitive.

Ternary combination of irinotecan, fluorouracil-folinic acid and oxaliplatin: results on human colon cancer cell lines

A marked antitumour efficacy is currently obtained by oxaliplatin (LOHP)-fluorouracil (FU)-folinic acid (FA) combination and by CPT11-FU-FA combination. Logically, the triple association LOHP, CPT11 and FUFA will be soon tested in cancer patients. The aim of the present study was to compare two schedules combining SN38 (the active metabolite of CPT11, irinotecan) with FU-FA and LOHP. The two schedules differed by the SN38 position. The relative contribution of each drug in the resulting global cytotoxicity was evaluated. Two human colon cancer cell lines were used (WIDR and SW620 both p53 mutated). LOHP plus FA were applied for 2 h, just before a 48 h FU exposure. The SN38 sequence was applied for 24 h, starting either 48 h before LOHP-FA (schedule A), or just after LOHP-FA exposure (schedule B). Cytotoxicity was assessed by the 3-(4,5-demethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) test and drug interactions were analysed according to the Chou and Talalay method, based on the computation of a combination index (CI). The SN38 position significantly induces a shift from additivity-antagonism when SN38 was applied after LOHP, towards additivity-synergism when SN38 was applied first (P = 0.03). The relative contribution (RC) of each drug in the overall cytotoxicity of the triple combination was defined as the drug concentration giving 50% cell lethality (IC(50)) of the double association without that drug divided by the IC(50)of the triple association. Whatever the SN38 position, the larger contribution was made by LOHP (median RC = 2.4) and the smaller by SN38 (median RC = 1.1). In addition, the contribution of FUFA was improved when SN38 was applied first (median RC = 2.2) as compared to the opposite schedule (median RC = 1.2). Results were in agreement between the two explored cell lines. The present data should be taken into account when establishing the rationale of future trials combining CPT11, LOHP and FU-FA.

An analysis of the therapeutic efficacy of protracted infusion of low-dose 5-fluorouracil and cisplatin in advanced gastric cancer

To analyze the clinical efficacy of a protracted infusion of low-dose 5-fluorouracil (5-FU) and cisplatin (CDDP), a phase II study was performed in 36 patients with advanced gastric cancer. The treatment schedule of the low-dose administration of 5-FU and CDDP (FP) was a continuous infusion of 5-FU (250 mg/m2) for 28 consecutive days and a drip infusion of CDDP (3.5 mg/m2) for 5 consecutive days, followed by a 2-day interval each week in one cycle. The overall response rate was 47.2%. Of importance, the improvement in quality of life assessed by performance status (PS) and oral intake was 13.9% and 33.3%, respectively. The toxicity in low-dose FP treatment was less than grade 2, including gastrointestinal toxicities and bone marrow suppression, and this was tolerable during the treatment. The median survival time (MST) and 1-year survival rate were 8 months and 36.2%, respectively. In a pharmacokinetic analysis following the protracted infusion of low-dose FP, the plasma concentrations of 5-FU and CDDP were increased to about 120-130 ng/ml and 0.3-0.5 microg/ml on day 21 after the treatment, respectively. The plasma concentrations of 5-FU and CDDP were not significantly different between responders and non-responders. The tumor response to low-dose FP treatment was associated with the induction of apoptotic cell death and with the overexpression of apoptosis-related genes, such as Bax and Bcl-Xs, in cancer cells. These results indicate that the protracted infusion of low-dose FP could be a useful regimen for patients with advanced gastric cancer, in terms of the high response rate and low toxicity, possibly leading to the prolongation of survival and improvement in the quality of life.

Effect of consecutive lower-dose cisplatin in enhancement of 5-fluorouracil cytotoxicity in experimental tumor cells in vivo

It is known that cisplatin (CDDP) potentiates the cytotoxicity of 5-fluorouracil (5-FU), and that the biochemical mechanism is an increase in the intracellular reduced folate levels in the tumor cells. We investigated the effect of consecutive administration with lower-dose CDDP on intracellular accumulation of reduced folate and the activity of methionine synthase, a key enzyme in intracellular methionine synthesis. When CDDP (1 mg/kg) was administered i.p. to ascitic Yoshida sarcoma-bearing rats for 4 consecutive days, both the reduced folate levels and methionine synthase activity in the cells significantly increased, as the same as a single 5 mg/kg dose of CDDP. Furthermore, when Yoshida sarcoma-bearing rats were pre-treated with 1 mg/kg CDDP for 5 consecutive days, [14C]L-methionine incorporation into the isolated ascitic cells was significantly inhibited as compared to that in non-treated cells, suggesting that consecutive administration of lower-dose CDDP is capable of inducing the intracellular modulation of reduced folate levels and methionine synthase activity via inhibition of cellular uptake of methionine. In addition, 5-day administration of lower-dose (1 mg/kg) CDDP potentiated the antitumor effect of 5 mg/kg S-1, a new oral preparation of tegafur, given for 7 consecutive days, and this combined effect was almost similar to the antitumor effect of a combination of S-1 and a single conventional dose (5 mg/kg) of CDDP. Consecutive lower-dose CDDP also may be concluded to act as an important modulator of the enhancement of 5-FU cytotoxicity in experimental tumors.

Conceptual changes in cancer chemotherapy: from an oral fluoropyrimidine prodrug, UFT, to a novel oral fluoropyrimidine prodrug, S-1, and low-dose FP therapy in Japan

The conventional concept in cancer chemotherapy considers that no efficacy can be attained without provoking adverse reactions. We presented concrete descriptions based on a novel concept allowing us to emerge from the old one. Relief of adverse reactions, e.g., diarrhea, stomatitis, anorexia, and H&F syndrome, not only improves QOL of the patient but also allows prolongation of the treatment period without lowering patient compliance. We describe in this paper a therapeutic modality which is based on SRC (self-rescuing concept) featuring dual activity, i.e., effect-enhancing activity and adverse reaction-reducing activity. We present the theory and practice of S-1, a novel oral fluoropyrimidine anticancer agent designed to enhance anticancer activity and reduce gastrointestinal toxicity through the deliberate combination of the following components: an oral fluoropyrimidine agent tegafur; a DPD inhibitor (CDHP) which is more potent than uracil used in UFT; and an ORTC inhibitor (Oxo) which localizes in the gastrointestinal tract. Furthermore, we refer to combination therapy with 5-FU (CIV) and low-dose consecutive CDDP in which CDDP was used as a modulator of 5-FU and to the theory and practice of combination therapy with 5-FU (CVI) intermittent (Monday, Wednesday, and Friday) administration and low-dose CDDP consecutive administration in which a difference in cell cycle between gastrointestinal mucosal cell and tumor cell or between bone marrow cell and tumor cell was utilized. We intend in future to combine the abovementioned therapeutic modalities provoking less adverse reactions and being gentle to patients with cancer in an effort to further increase their life expectancy.

Feasibility of daily concurrent chemoradiation therapy as nonsurgical management for esophageal cancer: our experience and theoretical background

BACKGROUND AND OBJECTIVES

Many combination patterns of chemotherapy and radiotherapy (chemoradiation therapy; CRT) for the treatment of esophageal cancer indicate that the optimal doses of chemotherapeutic agents and of chemotherapy and radiotherapy regimens remain unclear. The feasibility and promising outcome of our newly developed definitive CRT for nonsurgical management of esophageal cancer, essentially based on the theoretical backgrounds of the radiosensitizing and biochemical modulation effects of chemotherapeutic agents, is investigated.

METHODS

Six nonoperated esophageal cancer patients were treated by daily concurrent CRT, which consisted of continuous 5-fluorouracil administration with leucovorin, combined with a low dose of daily cisplatin administration before each fraction of radiation. Response to CRT and toxicities and survivals were evaluated.

RESULTS

Complete and partial responses were seen in 2 patients each. Histologic examination of the biopsy specimens in the primary site showed no cancer cells in 4 patients; 1 of them survived for 31 months after CRT. The other 2 patients showed good-quality survival, having dramatic relief from dysphagia. There were no treatment-related deaths.

CONCLUSIONS

The daily concurrent CRT is rational and promising and compares well with other series of definitive CRT. The CRT based on the theoretical background is feasible as a nonsurgical management option for esophageal cancer patients.

UFT plus cisplatin combination chemotherapy in the treatment of patients with advanced nonsmall cell lung carcinoma: a multiinstitutional phase II trial. For the Japan UFT Lung Cancer Study Group

BACKGROUND

Combination chemotherapy comprised of oral UFT (a combination of tegafur and uracil) and cisplatin was shown to be an effective regimen for the treatment of advanced nonsmall cell lung carcinoma and to be associated with a low incidence rate of toxicity in a previous, single institution, Phase II trial on a small patient sample. Therefore, the current multiinstitutional Phase II trial was conducted to confirm the earlier results.

METHODS

Eligible patients had histologically or cytologically confirmed Stage IIIB or IV nonsmall cell lung carcinoma and good performance status. Patients who had received prior treatment were excluded. All had measurable disease. UFT (400 mg/m(2)) was administered orally on Days 1-14, and cisplatin (80 mg/m(2)) was injected intravenously on Day 8. Treatment was repeated every 3-4 weeks.

RESULTS

Approximately 70% of the 108 eligible patients had systemic metastatic disease. All 108 patients were assessable for toxicity and survival, and 103 were assessable for response. Among these 103 patients there was 1 complete response and 29 partial responses, for an overall response rate of 29.1% (95% confidence limits [CL], 20.4-37.9%). The median survival time was 40 weeks and the 1-year survival rate was 39% (95% CL, 30-49%). The median progression free survival time was 28 weeks. Eastern Cooperative Oncology Group Grade 3 leukopenia and thrombocytopenia were observed in only 1 patient (0.9%) and 3 patients (2.8%), respectively. Grade 3/4 nonhematologic toxicities included elevated bilirubin (6.5%) and emesis (7.4%). One patient who had a past history of duodenal ulcer died of ulcer perforation 15 days after completing the first treatment cycle.

CONCLUSIONS

Oral UFT plus cisplatin is a moderately active regimen with an extremely low rate of incidence of myelosuppression as an adverse event, and warrants comparison with other cisplatin-based regimens in a prospective randomized trial.

Prevention by chitosan of myelotoxicity, gastrointestinal toxicity and immunocompetent organic toxicity induced by 5-fluorouracil without loss of antitumor activity in mice

We examined the antitumor activity and side effects (myelotoxicity, immunocompetent organic toxicity and gastrointestinal toxicity) of combined treatment with the cancer chemotherapy drug 5-fluorouracil (5-FU) and dietary fiber chitosan in sarcoma 180-bearing mice. 5-FU (12.5 mg/kg x 2/day) plus chitosan (150, 375 and 750 mg/kg x 2/day) inhibited the tumor growth as well as 5-FU alone. Chitosan (150 and 750 mg/kg x 2/day) blocked the reduction of blood leukocyte number caused by 5-FU administration, and it prevented the injury of the small intestinal mucosa membrane and delayed the onset of diarrhea induced by 5-FU. Furthermore, chitosan (750 mg/kg x 2/day) prevented the reduction of spleen weight induced by 5-FU in sarcoma 180-bearing mice, and the reduction of lymphocyte and CD8+ T cell numbers induced by 5-FU was also prevented by the oral administration of chitosan (750 mg/kg x 2/day) in C57BL/6 mice. Chitosan (150 and/or 750 mg/kg x 2/day) reduced the 5-FU incorporation into RNA fractions of small intestine and spleen without affecting the 5-FU incorporation into the tumor in sarcoma 180-bearing mice. These findings suggest that prevention of the 5-FU side effects by chitosan might be partly due to the selective inhibition of 5-FU uptake into the small intestine and spleen, resulting in the reduction of immune function toxicity, myelotoxicity and gastrointestinal toxicity of 5-FU. Therefore, it is concluded that the combination of chitosan and 5-FU might be useful for the prevention of side effects such as gastrointestinal toxicity, immunotoxicity and myelotoxicity caused by 5-FU.

Pre-operative chemoradiation therapy with 5-fluorouracil and low-dose daily cisplatin for esophageal cancer: a preliminary report

BACKGROUND

A combination of chemotherapy and radiotherapy (chemoradiation therapy; CRT) has recently been developed to improve the survival of esophageal cancer patients. However, the optimal choice of chemotherapeutic agents and their doses, as well as chemotherapy and radiotherapy regimens, remain unclear.

METHODS

Based on recent advances in knowledge on the radiosensitizing and biochemical modulation effects of chemotherapeutic agents, we have recently developed concurrent CRT which consisted of continuous 5-fluorouracil (5FU) administration (600 mg/m2/day, days 1-5) combined with a low dose of daily cisplatin administration (10 mg/m2/day, days 1-5, and 5 or 10 mg/m2/day, days 8-12 and 15-19) before each fraction of radiation (2 Gy each). To evaluate the efficacy and safety of our concurrent CRT, 10 esophageal cancer patients received one or one and a half courses of the CRT.

RESULTS

All patients tolerated and completed a full course of the CRT. The effectiveness of the CRT on the primary tumor included pathologically or endoscopically complete responses in three patients (30%), partial response in five (50%), no response in two (20%) and tumoral downstaging (T-classification) in five (50%). Grade 2 and Grade 3 toxicity, seen in six patients, did not affect surgical operation. No patients showed CRT-related deaths. Eight patients (80%) underwent resection with no operative mortality. Of these, two patients (25%) showed pathologically or endoscopically complete responses, and four (50%) showed partial response. Three patients died of cancer after resection. The two inoperable patients showed a pathologically complete response and partial response, respectively. They were relieved of their cancer-related complaints and were living without hospitalization at the time of this analysis.

CONCLUSIONS

These results suggest that the concurrent CRT based on the theoretical backgrounds is effective and has acceptable toxicities with maintaining its efficacy for the treatment of esophageal cancer patients.

Phase II trial of 5-fluorouracil and low-dose cisplatin in patients with squamous cell carcinoma of the esophagus

A phase II study was conducted to determine the clinical efficacy and toxicity of 5-fluorouracil (5-FU) and low-dose cisplatin (CDDP) in patients with squamous cell carcinoma of the esophagus. Chemotherapy consisted of 5-FU at a dose of 330 mg/m2 per day, given as a 24-h infusion on days 1-7, and CDDP at a dose of 6 mg/m2 per day, given as a 2-h infusion on days 1-5. Either two or four cycles of chemotherapy were administered to 20 patients with stage III advanced esophageal carcinoma. All 20 patients were then assessed for response and toxicity. An objective response was demonstrated by 11 of the 20 patients, with one complete response (CR) and ten partial responses (PR), bringing the response rate to 55%, with a 95% confidence interval of 27% to 83%. Surgical resection of the tumor was performed in all 20 patients. One patient was found to have a grade 3 histological CR. The median survival of all the patients was 20.5 months, with a range of 4.5 to 48.0 months. Neutropenia and thrombocytopenia developed in five (25%) and two (10%) patients, respectively, and the nonhematologic toxicities were insignificant. The findings of this phase II study indicate that preoperative treatment using 5-FU and low-dose CDDP chemotherapy for patients with advanced esophageal carcinoma appears to achieve a high response rate after short-term administration without affecting the quality of sophisticated lymph node dissection.

Sequence-dependent antitumour efficacy of combination chemotherapy of nedaplatin, a novel platinum complex, with 5-fluorouracil in an in vivo murine tumour model

The antitumour efficacy of a sequential combination of nedaplatin (NDP) and 5-fluorouracil (5-FU) was evaluated using Lewis lung carcinoma in vivo. NDP was developed as a second generation platinum complex. Because it has greater antitumour activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumour activity of NDP plus 5-FU with that of CDDP plus 5-FU. A fixed 5-FU dose was injected daily for 5 days and increasing doses of either NDP or CDDP were injected once via the tail vein into the Lewis lung carcinoma-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) resulted in severe body weight loss followed by the death of the tumour-bearing mice when the high-dose of NDP or CDDP was administered. In contrast, the sequential administration of 5-FU prior to NDP or CDDP (FN or FC therapy) resulted in synergistically enhanced inhibition of tumour growth and prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. At the high-dose of NDP in FN therapy, a reduction of tumour size and long-term tumour-free survival were frequently observed. The survival effect of the combinations of NDP with 5-FU was superior to those of the combination of CDDP with 5-FU. In conclusion, the sequence-dependent antitumour efficacy and toxicity of the combination of NDP or CDDP with 5-FU was demonstrated in this study, and FN therapy appeared to be the most efficient regimen as a clinical therapy.

Low-dose cisplatin-5-fluorouracil prevents postoperative suppression of natural killer cell activity in patients with gastrointestinal cancer

BACKGROUND

The effect of administering low-dose cisplatin (CDDP)-5-fluorouracil (5-FU) postoperatively on the activity of the immune system is not known. To clarify the effect on natural killer (NK) cell activity of treatment with low-dose CDDP-5-FU, we compared NK cell activity after surgery for gastrointestinal cancer in patients treated with low-dose CDDP-5-FU, a bolus dose of mitomycin C (MMC) or no anticancer drug.

METHODS

Sixty-two patients consisted of three groups: low-dose CDDP-5-FU (n = 15), MMC (n = 20) and no-drug (n = 27). Chemotherapy was initiated immediately after surgery. NK cell activity was measured on the day before surgery (pre-op) and on postoperative days 7 (POD7) and 21 (POD21).

RESULTS

The NK cell activities of the CDDP-5-FU group were 37.7% at pre-op, 36.1% on POD7 and 33.6% on POD21. However, the NK cell activities in the no-drug and MMC groups were significantly decreased on POD7 (from 36.6 to 24.8% and from 31.4 to 16.6%, respectively). The NK cell activity in the MMC group remained depressed on POD21 (18.6%) whereas that in the no-drug group recovered (31.6%).

CONCLUSIONS

Consecutive administration of low-dose CDDP-5-FU appears to be useful as postoperative adjuvant chemotherapy because of its preventive effect on NK cell suppression after surgery.

Co-variables influencing 5-fluorouracil clearance during continuous venous infusion. A NONMEM analysis

The objective of this study was to attempt to identify patient co-variables which could influence interpatient variability in 5-fluorouracil (5-FU) clearance during a 5-day continuous venous infusion (CVI, cisplatin 100 mg/m2 day 1 then 5-FU 1 g/m2/day days 2-6). The analysis was performed using a NONMEM program according to a linear one-compartment model. A total of 186 cycles (2 samples per day, 8 a.m. and 5 p.m.) were analysed from 104 patients with various cancers (the majority of head and neck and oesophagus). The study co-variables were age, sex, body surface area, hepatic metastases, peripheral mononuclear cell dihydropyrimidine dehydrogenase activity (PMNC-DPD), liver enzymes, clock-time (8 a.m. versus 5 p.m.), elapsed time during CVI. The data showed that 5-FU clearance was significantly reduced by increased age, low PMNC-DPD, high serum alkaline phosphatase and elapsed time during infusion. These data may be useful for improving knowledge of predictive factors which can influence 5-FU exposure and thus predispose to toxic manifestations.

Neoadjuvant chemotherapy followed by concurrent chemotherapy and radiotherapy for locally advanced esophageal carcinoma with bulky upper abdominal lymphadenopathy. Case report

A 60-year old male patient who had locally advanced esophageal carcinoma with bulky upper abdominal lymphadenopathy underwent neoadjuvant chemotherapy consisting of 5-fluorouracil (5-FU) and cisplatin (CDDP), followed by concurrent radiotherapy and chemotherapy using protracted low-dose continuous infusion of 5-FU and CDDP. The treatment brought about complete remission in the primary lesion and good partial remission in the upper abdominal lymphadenopathy. He subsequently underwent trans-hiatal esophagectomy after one cycle of adjuvant chemotherapy because local recurrence was suspected. Histopathologic study of the resected specimen demonstrated no malignant tissue in the primary lesion and the lymph nodes. The patient is still alive and disease-free at 26+ months. This result suggests that neoadjuvant chemotherapy followed by concomitant chemotherapy and radiotherapy for patients who have locally advanced squamous cell carcinoma of the esophagus with intensive abdominal lymphadenopathy may offer some chance for sterilization of local and regional metastases and longer survival.

A novel chemotherapy for advanced hepatocellular carcinoma with tumor thrombosis of the main trunk of the portal vein

BACKGROUND

Hepatocellular carcinoma (HCC) with tumor thrombosis of the main trunk of the portal vein (PVTT) has a poor prognosis. This study was designed to evaluate the efficacy of arterial infusion chemotherapy for advanced HCC of this type.

METHODS

Nine patients with HCC were treated by arterial infusion of a chemotherapeutic agent via a subcutaneously implanted injection port. One course consisted of the daily administration of cisplatin (10 mg for 1 hour on Days 1-5) and the subsequent infusion of 5-fluorouracil (250 mg for 5 hours on Days 1-5). In principle, patients were to receive four serial courses of chemotherapy.

RESULTS

The mean course of chemotherapy was 4.6 (range, 2.6-7.6) months. The serum total concentrations of alpha-fetoprotein and des-gamma-carboxyprothrombin were reduced after chemotherapy in most of the patients. Two patients showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the other two showed partial response (PR) (response rate [CR + PR/All cases], 44.4%). The 3-year survival rate was 40%. The mean survival after the therapy was 14.9 (range, 4.1-48.9) months. The 50% survival was 9.2 months. Adverse reactions were tolerable nausea and loss of appetite.

CONCLUSIONS

This chemotherapeutic regimen achieved favorable results and may be useful in treating patients with HCC with tumor thrombosis of the main trunk of the portal vein.

The cellular interaction of 5-fluorouracil and cisplatin in a human colon carcinoma cell line

The combination of 5-fluorouracil (5-FU) and cisplatin (CDDP) has been shown to have synergistic cytotoxicity in human tumours, but the biochemical mechanism for this interaction remains unclear. Therefore, the aim of this study was to investigate the interaction of 5-FU and CDDP in a human colon carcinoma cell line, NCI H548. A 24 h exposure to 5-FU resulted in a 5-FU IC50 value of 24.2 +/- 4.5 microM, Dm 22.6 microM; exposure to CDDP for 2 h resulted in a IC50 value of 20.8 +/- 8.0 microM, Dm 21.9 microM. When cells were exposed simultaneously to 5-FU for 24 h and CDDP for the initial 2 h, or when cells were treated with CDDP for 2 h followed by various concentrations of 5-FU for 24 h, no greater than additive cytotoxicity was observed. In contrast, when cells were treated with 5-FU for 24 h prior to CDDP for 2 h, a greater than additive interaction was noted (5-FU IC50 1.2 +/- 0.6 microM, Dm 1.3 microM, CI 0.45). Thymidine 10 microM partially reversed the growth inhibitory effects of the 5-FU/ CDDP combination. Using both immunological and biochemical assays, no notable differences in the total amount of TS enzyme or the fraction of bound TS enzyme could be detected in the absence or presence of CDDP. No notable differences could be detected in intracellular reduced folate pools, FdUMP or FUTP pools, or 5-FU incorporation into RNA or DNA with the addition of CDDP to 5-FU. DNA fragmentation studies revealed that the combination of 5-FU followed by CDDP demonstrated a greater degree of single-stranded DNA fragments in parental (P = 0.024) and newly synthesised DNA (P = 0.025) compared with the administration of CDDP prior to 5-FU or either drug alone. The increase in smaller DNA fragment size was reversed with the addition of thymidine (10 microM). These findings suggest that the interaction of 5-FU and CDDP is associated with a greater degree of fragmentation of both nascent and parental DNA.

Inhibition of methionine uptake by cis-diamminedichloroplatinum (II) in experimental brain tumors

cis-diamminedichloroplatinum (II) (CDDP) has been used both alone and in combination with other chemotherapeutics for cancer chemotherapy. Although CDDP acts primarily on DNA, it can also act at the tumor-cell membrane to inhibit methionine transport. The latter mechanism of CDDP is reported to have an important role as a chemical modulator in enhancing chemotherapeutic effects of 5-fluorouracil in tumor cells. We report here the effects of CDDP on methionine uptake in an in vivo brain-tumor model. C6 brain-tumor cells were stereotactically inoculated in the right basal ganglia of 6-week-old male Sprague-Dawley rats. Ten days after the inoculation, autoradiographic images were obtained using (14C-methyl)-L-methionine. The tracer uptake, represented as differential absorption ratio (DAR) and an acid-insoluble fraction (AIF), was measured in both brain tumors and normal brain with or without an intravenous injection of CDDP. The tumor/non-tumor DAR and AIF decreased significantly (P < 0.01, as determined by the Mann-Whitney U-test) after CDDP treatment, whereas the non-tumor DAR and AIF remained almost unchanged. These findings indicate that CDDP inhibits methionine uptake selectively in brain-tumor tissue and may therefore be a potent chemical modulator in the chemotherapy of brain tumors.

Effect of cisplatin in advanced colorectal cancer resistant to 5-fluorouracil plus (S)-leucovorin

Modulation of 5-fluorouracil (5-FU) is currently being investigated in advanced colorectal cancer. In an attempt to improve the results obtainable for the association of 5-FU and leucovorin, we decided to add cisplatin to 5-FU and (6S)-leucovorin (S-LV) after disease progression. The hypothesis was that a pharmacological enhancement of the efficacy of 5-FU would result in responses in 5-FU-unresponsive patients or in a second response in previously responding patients. A group of 28 5-FU+S-LV-pretreated patients, with advanced measurable colorectal cancer, were treated with 80 mg/m2 cisplatin on day 1, 80 mg/m2 S-LV and 370 mg/m2 5-FU as an i. v. bolus for 5 consecutive days every 4 weeks. We obtained 3 partial responses (response rate: 11 +/- 11%), while 11 patients had stable disease (39 +/- 18%). Among the 3 responders, 1 patient had earlier achieved a partial response, a second stable disease and 1 had disease progression after the previous 5-FU+S-LV treatment. The median survival time for all 28 patients was 11 months. Toxicity was minimal and consisted of mild and reversible gastrointestinal symptoms and myelosuppression. We believe that further studies must be carried out to establish the real impact of the synergism between cisplatin, 5-FU and S-LV in untreated patients.

A phase II trial of oral tegafur and uracil plus cisplatin in patients with inoperable nonsmall cell lung cancer

BACKGROUND

The combination of uracil and tegafur in a 4:1 molar concentration (UFT) has a greater antitumor activity than 5-fluorouracil (5-FU) and tegafur. Because the combination of 5-FU and cisplatin has been proven to have a synergistic antitumor effect in many experimental and clinical studies, a Phase II study was conducted using the combination of UFT and cisplatin in patients with inoperable nonsmall cell lung cancer.

METHODS

Thirty-one patients with measurable disease were entered into the study; all were evaluable for toxicity and response. Their median age was 61 years (range, 36-75 years). There were 13 patients with Stage III and 17 with Stage IV disease. Twenty-two (71%) patients had received no prior treatment. UFT (400 mg/m2) was administered orally on days 1 through 21 and cisplatin (80 mg/m2) was injected intravenously on day 8. This treatment was repeated every 4 weeks.

RESULTS

The median number of treatment cycles was two (range, 1-4 cycles). There were 11 partial responses (35%; 95% confidence interval, 19%-52%). The median response time was 6 months (range, 3-13 months). The median survival time was 11 months (range, 4-27+ months) for Stage III and 8 months (range, 2-22 months) for Stage IV. This chemotherapy regimen was well tolerated. The hematologic toxicities, such as leukopenia and thrombocytopenia of grades 3 and 4, occurred in only 2 of 31 (6%) patients. Nonhematologic toxicities of grades 3 or 4 were not observed.

CONCLUSIONS

Oral UFT plus cisplatin administration demonstrated an activity comparable with that of other combinations based on cisplatin and an extremely low incidence of side effects. These observations suggest that this chemotherapy regimen is worthy of further investigation in a multi-institutional trial to determine the antitumor effect and the quality of life of patients.

Changes in folate concentration in Yoshida sarcoma after administration of leucovorin or cisplatin

Both leucovorin (LV) and cisplatin (cis-dichlorodiammine platinum II, CDDP) act as modulators of 5-fluorouracil (5-FUra) by increasing the intracellular concentration of reduced folate. We measured intracellular folate levels following the administration of LV or cisplatin in tumor-bearing rats to determine the optimal schedules for their use as 5-FUra modulators. Donryu rats were inoculated with Yoshida sarcoma cells on the right flank. Seven days after tumor inoculation, the animals were injected with LV or CDDP. The kinetic and dose-related changes in intracellular folate concentration were analyzed by means of a binding assay. Folate levels in the tumor tissues were significantly higher than baseline 1 and 2 h after administration of LV and remained significantly high until 8 h after administration. Folate levels in the tumor tissues were significantly higher than baseline 1 and 2 h after cisplatin administration, then decreased to a rather low level 8 h after, and to a significantly lower level than baseline 24 h after administration. The folate levels in the tumor tissue increased in proportion to the dose of LV, but did not increase when the dose of cisplatin was increased from 1 mg/kg to 8 mg/kg. Repeat high-dose administration of LV and repeat low-dose administration of cisplatin are advocated when they are used as modulators of 5-FUra.