Feasibility study on protracted infusional 5-fluorouracil and consecutive low-dose cisplatin for advanced gastric cancer

Sustained co-delivery of 5-fluorouracil and cis-platinum via biodegradable thermo-sensitive hydrogel for intraoperative synergistic combination chemotherapy of gastric cancer

Gastric cancer is the fifth most common cancer and the third leading cause of cancer death worldwide, posing a severe threat to human health. Surgical resection remains the most preferred option for gastric cancer treatment. However, for advanced gastric cancer, the curative effect of surgical resection is usually limited by the local recurrence, peritoneal carcinomatosis, or distal metastasis. Intraoperative chemotherapy is an attractive in situ adjuvant treatment strategy to reduce the recurrence and metastasis after surgical resection. Here, we designed a 5-fluorouracil (5-FU) and cis-platinum (DDP) co-delivery system based on a biodegradable temperature-sensitive hydrogel (PDLLA-PEG-PDLLA, PLEL) for intraoperative adjuvant combination chemotherapy of gastric cancer. This 5-FU + DDP/PLEL hydrogel system characterized by a special sol-gel phase transition in response to physiological temperature and presented sustained drug release in vitro and in vivo. A strong synergistic cell proliferation inhibition and apoptosis promotion of 5-FU + DDP/PLEL were observed against gastric cancer MKN45-luc cells. After intraperitoneal injection, the dual-drug loaded hydrogel formulation showed superior anti-tumor effects than the single-drug carrying hydrogels and combination of free 5-FU and DDP on the gastric cancer peritoneal carcinomatosis model. The use of hydrogel for dual-drug delivery had benefited to fewer side effects as well. What's more, we established a mouse model for postsurgical residual tumors and peritoneal carcinomatosis of gastric cancer, in which the intraoperative administration of 5-FU + DDP/PLEL also remarkably inhibited the local recurrence of the orthotopic tumors and the growth of the abdominal metastatic tumors, resulting in an extended lifetime. Hence, this developed dual-drug loaded hydrogel system has great potential in the intraoperative chemotherapy of gastric cancer, that suggests a clinically-relevant and valuable option for postsurgical management of gastric cancer.

•

Intraoperative chemotherapy could reduce the recurrence and metastasis after surgical resection of gastroenteric tumors.

•

5-FU and DDP co-delivery system based on PLEL was developed for intraoperative combination chemotherapy of gastric cancer.

•

This dual-drug loaded hydrogel helped to improve synergistic anti-tumor effects and reduce adverse side effects in vivo.

•

5-FU+DDP/PLEL could inhibit recurrence of orthotopic tumors and growth of abdominal metastatic tumors in gastric cancer.

Clinical outcomes of TS-1 chemotherapy for advanced and recurrent gastric cancer

Purpose

Titanium silicate (TS)-1 chemotherapy has been widely used against gastric cancer in Japan. The aim of the present study was to assess the efficacy and hematological safety of TS-1 as treatment for advanced and recurrent gastric cancer.

Methods

From September 2006 to February 2011, 51 advanced or recurrent gastric cancers were treated with TS-1. One course of treatment consisted of 40, 50, or 60 mg/m² of TS-1 twice a day for 28 days, followed by withdrawal for two weeks. The primary end point was progression-free survival (PFS), and the secondary end point was overall survival (OS).

Results

The disease control rate was 39.2% (complete response, 0/51; partial response, 6/51; stable disease, 14/51; progressive disease, 23/51; not evaluable, 8/51). The median PFS was 4.0 months (95% confidence interval [CI], 2.2 to 5.7); the median PFS of the advanced group was 6.0 months (95% CI, 2.8 to 9.1), and the median PFS of the recurrent group was 3.0 months (95% CI, 1.8 to 4.1). The median OS was 11.0 months (95% CI, 6.3 to 15.6); the median OS of the advanced group was 10.0 months (95% CI, 4.9 to 15.0), and the median OS of the recurrent group was 14.0 months (95% CI, 4.1 to 23.8). Grade 3 or 4 hematological toxicity occurred in three patients (5.9%), anemia occurred in two patients (3.9%), and thrombocytopenia occurred in one patient (2%).

Conclusion

TS-1 chemotherapy was safe and effective, with relatively long PFS and OS in patients with advanced and recurrent gastric cancers.

Development history and concept of an oral anticancer agent S-1 (TS-1): its clinical usefulness and future vistas

Dushinsky et al. left a great gift to human beings with the discovery of 5-fluorouracil (5-FU). Approximately 50 years have elapsed from that discovery to the development of S-1 (TS-1^®). The concept of developing an anticancer agent that simultaneously possesses both efficacy-enhancing and adverse reaction-reducing effects could be achieved only with a three-component combination drug. S-1 is an oral anticancer agent containing two biochemical modulators for 5-FU and tegafur (FT), a metabolically activated prodrug of 5-FU. The first modulator, 5-chloro-2,4-dihydroxypyridine (CDHP), enhances the pharmacological actions of 5-FU by potently inhibiting its degradation. The second modulator, potassium oxonate (Oxo), localizing in mucosal cells of the gastrointestinal (GI) tract after oral administration, reduces the incidence of GI toxicities by suppressing the activation of 5-FU in the GI tract. Thus, S-1 combines FT, CDHP and Oxo at a molar ratio of 1:0.4:1. In 1999–2007, S-1 was approved for the treatment of the following seven cancers: gastric, head and neck, colorectal, non-small cell lung, breast, pancreatic and biliary tract cancers. ‘S-1 and low-dose cisplatin therapy’ without provoking Grade 3 non-hematologic toxicities was proposed to enhance its clinical usefulness. Furthermore, ‘alternate-day S-1 regimen’ may improve the dosing schedule for 5-FU by utilizing its strongly time-dependent mode of action; the former is characterized by the low incidences of myelotoxicity and non-hematologic toxicities (e.g. ≤Grade 1 anorexia, fatigue, stomatitis, nausea, vomiting and taste alteration). These two approaches are considered to allow long-lasting therapy with S-1.

Haishengsu as an adjunct therapy to conventional chemotherapy in patients with non-small cell lung cancer: a pilot randomized and placebo-controlled clinical trial

OBJECTIVE

To investigate the effect of Haishengsu, an extract from Tegillarca granosa, on non-small cell lung cancer as an adjunct to conventional chemotherapy. DESIGNS/SETTINGS: Randomized, double-blind, placebo-controlled trial was conducted in 83 patients. The Haishengsu (n=42, 2.4mg Haishengsu in 250ml normal saline, iv, for 15 days) and the placebo group (n=41, 250ml normal saline, iv) were also treated with two cycles (28 days for each cycle) of conventional chemotherapy consisting mitomycin, vindesine and cisplatin.

RESULTS

The curative effect of conventional chemotherapy was observed in 62% of Haishengsu group patients and in 39% in of the placebo group patients (P=0.04, RR 1.59, 95% CI: 1.01-2.49). Improvement in Karnofsky performance status scores was seen in 66.7% of Haishengsu group patients and in 17.1% of the placebo group patients (P<0.01, RR 3.63, 95%CI: 1.77-7.41). The ratio of patients with no or only mild gastrointestinal reaction in the Haishengsu and the placebo group was 83.3% and 39.0%, respectively (P<0.01, RR 2.13, 95% CI: 1.42-3.20).

CONCLUSIONS

This study suggests that Haishengsu may be an effective adjunct therapy to the conventional chemotherapy for non-small cell lung cancer. The short-term therapeutic effect of chemotherapy may be improved and the chemotherapy-induced nausea or vomiting may be reduced by concurrent Haishengsu administration.

Predictive value of GADD153, p21 and c-Jun for chemotherapy response in gastric cancer

We sought to determine whether changes in the expression of early response genes (GADD153, p21 and c-Jun) are indicators of chemotherapy response in gastric cancer. Three human gastric cancer cell lines were exposed to 5-fluorouracil or cisplatin in vitro. Xenografts of TMK-1 cells in nude mice were also treated with 5-fluorouracil or cisplatin in vivo. For each of these treatments, we tested for a correlation between early gene expression levels and inhibition ratios derived at a later time. A 5-fluorouracil derivative, S-1, and cisplatin were administered to 12 patients with advanced gastric cancer for 3 weeks. Gene expression levels were measured using biopsy specimens obtained by endoscopy soon after initiation of chemotherapy. There was a significant correlation between expression levels of these genes at 24 h and inhibition ratios at 72 h in vitro. Cut-off values determined from receiver-operating characteristic curves were 1.3 for GADD153, 1.8 for p21 and 2.1 for c-Jun There was also a significant correlation between gene expression levels at 2 days and inhibition ratios at 21 days in vivo. Cut-off values were 1.8 for GADD153, 1.9 for p21 and 2.2 for c-Jun. Levels of early response gene expression in patients showing progressive disease were significantly lower than those in patients with partial response. Changes in the expression of the three early response genes soon after drug administration could improve predictions of the final outcome of chemotherapy in gastric cancer.

Thymidylate synthase and dihydropyrimidine dehydrogenase are related to histological effects of 5-fluorouracil and cisplatin neoadjuvant chemotherapy for primary gastric cancer patients

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and vascular endothelial growth factor (VEGF) are associated with the effect of 5-fluorouracil (5-FU) based adjuvant chemotherapy. However, very few studies have investigated the relationship between these factors and 5-FU neoadjuvant chemotherapy for primary gastric cancer patients. In this study, we studied the correlation between these markers and the histological chemotherapeutic effect in advanced gastric cancer with neoadjuvant chemotherapy.

METHODS

Sixty-two primary advanced gastric cancer patients were recruited into the study. One cycle of continuous infusion of 5-FU (300 mg/m2/day, 14 days) plus drip infusion of cisplatin (15 mg/m2/day, Day one and Day two) was performed as neoadjuvant chemotherapy. Histological chemotherapeutic responses of the resected specimens were classified into responders and nonresponders. TS, DPD, VEGF expressions both before and after neoadjuvant chemotherapy were examined immunohistochemically.

RESULTS

There was an association between the TS-low group and the responders (p < 0.05); the DPD-low group and the responders in both biopsy and surgical specimens (p < 0.01). A combination of the low-TS and low-DPD group was further associated with responders (p < 0.01). The immunoexpressions of biopsied and surgical specimens were significantly associated with each other.

CONCLUSION

Neoadjuvant chemotherapy for primary gastric cancer with one cycle of 5-FU and cisplatin was associated with histological findings in patients with low baseline TS and DPD. This dual determination may predict for efficacy of neoadjuvant treatment with these drugs.

Enhancement of the anti-tumor activity of S-1 by low-dose cisplatin in mice bearing the sarcoma-180 model

The combination of S-1, consisting of 1 mol/l tegafur, 0.4 mol/l 5-chloro-2,4-dihydroxypyridine and 1 mol/l potassium oxonate, plus low-dose cisplatin has showed promising anti-tumor activities in experimental and clinical studies. The aim of this study was to investigate the mechanism of this combination chemotherapy. Mice bearing sarcoma-180 cells were divided into groups of seven animals each - Group A: no treatment; Group B: 5-fluorouracil (5-FU) 10 mg/kg continuous i.p. infusion; Group C: S-1 10 mg/kg p.o.; Group D: cisplatin 0.2 mg/kg i.p.; Group E: B+D; Group F: C+D. Treatments were given for 5 consecutive days, and then anti-tumor activity, the concentration of 5-FU, the thymidylate synthase inhibition rate (TSIR) and the level of 5-FU incorporated into RNA (F-RNA) in tumor tissue were evaluated. Anti-tumor activity in Group F was higher than in any other group. A significantly higher concentration of 5-FU in tumor was detected in the S-1-treated groups (C and F) than in the 5-FU-treated groups (B and E). No differences in TSIR were observed between the groups treated with 5-FU or S-1 with or without cisplatin; however, the F-RNA level in Group F was about 1.24 times significantly higher than that in Group C. Group F showed the highest anti-tumor activity, with increasing intratumoral levels of 5-FU and F-RNA, but not that of TSIR. These results suggested that the superior anti-tumor activity obtained by S-1+cisplatin might be associated with an incorporation of 5-FU into RNA.

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.

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.

S-1 in the treatment of advanced and recurrent gastric cancer: current state and future prospects

BACKGROUND

S-1 (TS-1) is a novel oral anticancer drug. Because of the excellent results of phase II studies, we continued to prescribe S-1 for advanced or recurrent gastric cancer after we participated in the phase I and II studies.

METHODS

Twenty-nine patients with advanced or recurrent gastric cancer were treated with S-1. Clinicopathological features, survival, and adverse reactions were analyzed.

RESULTS

One course of treatment consisted of 40, 50, or 60 mg/body twice a day for 28 days followed by withdrawal for 2 weeks. The mean number of treatments was 3.6 courses (range, 1-12 courses). The response rate was 37.9% (11 partial responses [PRs] in 29 patients). Although the response rate of patients who did not receive prior chemotherapy was 47.6% (10 PRs in 21 patients), that of patients with prior chemotherapy was 12.5% (1 PR in 8 patients). The median survival time was 14.1 months, and that of patients who responded to treatment was 22.1 months, which was significantly longer than that of nonresponder patients. One-year and 2-year survivals in the 29 patients were 50.2% and 24.3%, respectively. Adverse reactions were noted in 17 of 29 patients, and the most frequent one was leukocytopenia. Only 2 patients experienced grade 3 leukocytopenia and neutrocytopenia.

CONCLUSION

Because of the high response rate and low incidence of severe adverse reactions, S-1 is a first-line chemotherapy that can be used for outpatients, especially for patients without prior chemotherapy. As the response rate for patients with prior chemotherapy was low, combined therapy with S-1 is worth evaluating for these patients.

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.

Intermittent FLDP: 24-h infusion of 5-FU on days 1, 3 and 5 combined with low-dose cisplatin on days 1-5 for gastric cancer, and its pharmacologic and kinetic rationale

PURPOSE

To improve the therapeutic efficacy and minimize the toxicity of 5-fluorouracil (5-FU), intermittent therapy consisting of alternate 24-h intravenous infusion and based on differences in generation time (T(G)) between normal cells and tumor cells was investigated.

METHODS

Two human gastric cancer cell lines MKN-7 and MKN-74 with T(G) of 35 h and 17 h, respectively, were used in an in vitro cytotoxic assay. The drug exposure schedule consisted of a continuous 144-h exposure and alternate 24-h exposures. In a clinical trial, a total of 23 patients with advanced or recurrent gastric cancer were treated with intermittent therapy consisting of 24-h intravenous infusion with 5-FU 700 mg/m(2) per day on days 1, 3 and 5 in combination with low-dose cisplatin (CDDP) at 3.3 mg/m(2) per day on days 1 to 5. One cycle of the combined chemotherapy lasted for four consecutive weeks, followed by withdrawal over 1-2 weeks. Plasma 5-FU concentrations were measured by high-performance liquid chromatography in 15 patients and dihydropyrimidine dehydrogenase (DPD) activity in peripheral blood mononuclear cells (PBMC) was measured in 13 patients.

RESULTS

The in vitro study revealed no statistically significant difference in cytotoxicity of 5-FU between the two drug exposure schedules in MKN-7 cells. In MKN-74 cells, however, a statistically significant decrease in cytotoxicity was found with the alternate 24-h exposure. In a clinical trial, plasma 5-FU concentrations showed a trapezoidal pattern. There was a significant correlation between DPD activity in PBMC and total body clearance of 5-FU. There were eight partial responders (8/22, 36%). Toxicities were very mild in severity, with no grade 3 or 4 toxicity. In particular, diarrhea and stomatitis were infrequent (one patient), and none of the patients developed thrombocytopenia.

CONCLUSIONS

Toxicities which may be observed in rapidly growing cells such as bone marrow cells and gastrointestinal epithelial cells following continuous intravenous infusion of 5-FU seemed to be reduced by intermittent therapy of 5-FU consisting of alternate 24-h intravenous infusions.

Intratumoral injection of dendritic cells after treatment of anticancer drugs induces tumor-specific antitumor effect in vivo

We investigated the in vivo antitumor effects of intratumoral (i.t.) administration of dendritic cells (DC) after low-dose chemotherapy using cisplatin + 5-FU. Combination of i.t. injection of DC and systemic chemotherapy induced complete rejection of the treated tumor, MC38 murine adenocarcinoma. Furthermore, the antitumor effects were also observed on a distant tumor inoculated in the contralateral flank of the animal. When 10x the number of tumor cells were inoculated, the antitumor effect of the combination of DC after chemotherapy was also confirmed and in comparison to that of DC or chemotherapy alone, thereafter contributed to a greater prolongation of survival. To analyze the mechanisms of the systemic antitumor effect generated in this system, we assessed the cytolytic activity against inoculated tumors. The cytolytic activity of effector cells from treated animals was shown to be tumor-specific and was mainly CD8 and MHC Class-I (p < 0.01) restricted. CD4 and MHC Class-II treatment marginally inhibited the cytolytic activity but not significantly (p = 0.07, 0.08 respectively). The cytolysis of effector cells was enhanced more significantly by the treatment of both DC and chemotherapy, than that of either DC or chemotherapy alone. Our study suggests that the strategy of i.t. injection of DC after low-dose chemotherapy could be a powerful weapon to treat patients with cancer in the clinical settings.

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.

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.

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.

A dose-finding study of raltitrexed (tomudex) with cisplatin and epirubicin in advanced gastro-oesophageal adenocarcinoma

The standard treatment for advanced gastro-oesophageal cancer in the UK is epirubicin, cisplatin and continuous infusion 5-fluoruracil by an indwelling central venous catheter (ECF), which has significant morbidity. Raltitrexed (tomudex), a specific inhibitor of thymidylate synthase with a long plasma terminal half-life (50-100 h) has activity in gastro-intestinal tract malignancy. To reduce the Hickman line-associated morbidity of ECF; we have conducted a dose-finding study of tomudex combined with epirubicin and cisplatin. Twenty-four patients (22 males, two female), median age 63 years (range 21-75), ECOG performance status < or =2 with histologically proven, unresectable or metastatic gastric (14 patients), gastro-oesophageal junction (nine patients) or oesophageal (one patient) adenocarcinoma received treatment with 3-weekly cisplatin 60 mg m(-2), epirubicin 50 mg m(-2) and tomudex at doses of 2 mg m(-2), 2.5 mg m(-2) or 3 mg m(-2) in successive cohorts. Six patients were treated per dose level with no intra-patient dose escalation. Dose escalation occurred after six patients had completed at least one cycle of chemotherapy at the previous dose level. After defining the maximum tolerated dose a further six patients were treated at the preceding dose level to assess toxicity at the proposed phase II dose. A total of 102 cycles (50% completed 6 cycles) were administered. The dose-limiting toxicities are neutropenia and diarrhoea occurring in 2/6 patients at the 3 mg m(-2) dose level. Of those patients evaluable for response, there were eight partial and one complete response (overall response rate 38%). The median survival was 9.9 months. ECT is an active regimen in oesophagogastric adenocarcinoma. The recommended dose of tomudex for further study in combination with epirubicin and cisplatin is 2.5 mg m(-2).