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

Phase II trial of capecitabine plus modified cisplatin (mXP) as first-line therapy in Japanese patients with metastatic gastric cancer (KSCC1104)

Purpose

Capecitabine plus cisplatin (XP) is a standard therapy for metastatic gastric cancer (mGC). However, while results from previous phase III trials suggested that the cisplatin dosage should be reduced in Japanese patients, no clinical data exist to support this. Here, we conducted a multicenter study to evaluate the efficacy and safety of modified XP (mXP) in Japanese patients with mGC.

Methods

Patients with previously untreated mGC received mXP (cisplatin 60 mg/m² on day 1 plus capecitabine 1000 mg/m² twice daily on days 1–14) every 3 weeks. The primary endpoint was the Response Evaluation Criteria in Solid Tumors-confirmed overall response rate (ORR). A sample size of 40 was planned for a threshold ORR of 30% and an expected value of 50%, with a one-sided α of 0.05 and a beta of approximately 0.2.

Results

Forty-two patients were enrolled. One patient did not fulfill the eligibility criteria; therefore, a total of 41 patients were assessed. The results were as follows: complete response in 2 patients, partial response in 16, stable disease in 14, progressive disease in 8, and no evaluation in 1. The confirmed ORR was 43.9% (95% confidence interval 28.7–59.1%). The median progression-free survival and median overall survival were 4.6 and 11.3 months, respectively. The most common grade 3 or 4 adverse events were neutropenia (37.5%), anemia (24.4%), anorexia (24.4%), and nausea (12.2%).

Conclusions

First-line chemotherapy with mXP in Japanese patients with mGC did not reach its primary objective. However, it did show a promising response rate and an acceptable tolerability profile.

S-1: a promising new oral fluoropyrimidine derivative

S-1 is an oral fluoropyrimidine that is designed to improve the antitumor activity of 5-fluorouracil (5-FU) concomitantly with an intent to reduce its toxicity. S-1 consists of tegafur, a prodrug of 5-FU combined with two 5-FU biochemical modulators:5-chloro-2,4-dihydroxypyridine (gimeracil or CDHP), a competitive inhibitor of dihydropyrimidine dehydrogenase and oteracil potassium which inhibits phosphorylation of 5-FU in the gastrointestinal tract decreasing serious gastrointestinal toxicities,including nausea, vomiting, stomatitis and diarrhea. Being an oral agent, S-1 offers convenience of administration and prevents complications of central venous access such as infection, thrombosis and bleeding. S-1 has shown efficacy in both gastrointestinal as well non-gastrointestinal malignancies. The authors review the current literature and provide their expert opinion on the incorporation of S-1 in the treatment of solid malignancies [corrected].

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.

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.

Decreased constitutive nitric oxide synthase, but increased inducible nitric oxide synthase and endothelin-1 immunoreactivity in aortic endothelial cells of donryu rats on a cholesterol-enriched diet

The Donryu rat is resistant to a high cholesterol diet in that typical atheromatous lesions do not develop. Using electron microscopic immunocytochemical techniques, the effects of a CCT diet (4% cholesterol with 1% cholic acid and 0.5% thiouracil) on the distributions of neuronal, macrophage, and endothelial specific nitric oxide synthase (NOS I, NOS II, and NOS III) and endothelin-1 (ET-1) immunoreactivity were examined in the thoracic aortic intima. Atheromatous lesions were absent, but immunocytochemistry showed 1. 4+/-0.52% and 4.0+/-0.9% endothelial cells (EC) with positive staining for NOS I and NOS III, respectively, compared with 16.3+/-2. 5% and 88.6+/-2.48% in control Donryu rats. The CCT-supplemented diet induced expression of NOS II immunoreactivity in thoracic aortic intimal cells. EC, subendothelial macrophages, and smooth muscle cells (SMC) also showed high NOS II-positive staining. The percentage of NOS II-immunoreactive EC was 43+/-1.8%. In control groups, no NOS II immunoreactive cells were observed. The percentage of ET-1 immunopositive cells was also significantly increased by 9. 2+/-0.66% and 64.2+/-1.4% in control and CCT-fed groups, respectively. It is concluded that the administration of a high cholesterol diet in Donryu rats produces endothelial dysfunction associated with changes in the balance of the different isoforms of NOS and ET-1. Therefore, the increase in inducible NOS and ET-1 immunoreactivity seen during the cholesterol-enriched diet appears to be a compensatory reaction of aortic wall cells to the high cholesterol supplementation.

Reduced sympathetic noradrenergic neurotransmission in the tail artery of Donryu rats fed with high cholesterol-supplemented diet

1. Sympathetic neurotransmission and noradrenaline content of the tail artery of Donryu rats fed for 2 months with a cholesterol-supplemented diet enriched with 4% cholesterol, 1% cholic acid, 0.5% thiouracil (CCT), were examined. 2. Total serum cholesterol level of CCT fed rats (7.05 +/- 1.77 mg ml(-1), n = 8) was significantly greater than lab-chow fed controls (2.58 +/- 0.32 mg ml(-1), n = 8). Low density lipoprotein level was also significantly increased in CCT-fed (1.79 +/- 0.26 mg ml(-1), n = 8) compared with control fed rats (1.35 +/- 0.25 mg ml(-1), n = 8) but plasma levels of triglyceride and high density lipoproteins did not differ significantly between the two groups. 3. Contractile responses of the arterial rings to transmural nerve stimulation (65 V, 0.1 ms, 4-64 Hz, 1 s), were markedly attenuated in the CCT fed animals compared with the controls. This reduction involved the noradrenergic rather than purinergic component of sympathetic transmission. 4. Vasoconstrictor responses to exogenous noradrenaline (0.01-300 microM) and adenosine 5'-triphosphate (0.3-1000 microM) were unaffected by CCT diet, indicating prejunctional alteration of sympathetic neurotransmission during CCT-induced hyperlipidaemia. 5. The noradrenaline content of the tail arteries of CCT fed animals (2.64 +/- 0.36 ng mg(-1), n = 6) was significantly lower than that of controls (3.82 +/- 0.32 ng mg(-1), n = 6). 6. These findings show that chronic treatment of Donryu rats with a cholesterol-supplemented diet led to altered levels of circulating lipid fractions accompanied by attenuated sympathetic noradrenergic neurotransmission and reduced noradrenaline content of the rat tail artery.

Relevance of tumoral folylpolyglutamate synthetase and reduced folates for optimal 5-fluorouracil efficacy: experimental data

The purpose of this study was to investigate folate-related predictors of 5-fluorouracil (5-FU) cytotoxicity in the presence or absence of l-folinic acid (l-FA). Intracellular concentrations of the reduced folates (tetrahydrofolate + 5,10-methylenetetrahydrofolate) and folylpolyglutamate synthetase (FPGS) activity were determined in 14 human cancer cell lines expressing a spontaneous sensitivity to 5-FU. On these 14 cell lines grown without l-FA supplementation, a significant positive correlation was demonstrated between basal intracellular folate concentration and FPGS activity. 5-FU sensitivity (IC50 range 0.6-25.4 microM) was not related to the basal intracellular folate concentration, whereas, significantly, it was linked to FPGS activity (range 2.5-11.1 pmol/min/mg protein): the higher the FPGS activity, the greater the 5-FU sensitivity. Under l-FA supplementation (0.01-300 microM), intracellular reduced folates increased continuously without evidence of saturation in all cell lines; the pattern of accumulation was independent of the FPGS activity. l-FA enhanced 5-FU cytotoxicity by a factor of 1.9-6.4 in 12 of the 14 cell lines. In the 12 FA-sensitive cell lines, the l-FA concentrations allowing 90% of maximum 5-FU potentiation [l-FA]90 ranged between 0.7 and 107.9 micro M (median 1.9); in contrast, the intracellular concentrations of reduced folates allowing 90% of maximum 5-FU potentiation were much less variable (range 7.6-38.3, median 24.8 pmol/mg protein). In the presence of [l-FA]90, 5-FU sensitivity remained significantly correlated to the basal FPGS activity. In addition, reduced folates were measured in 96 tumoral samples (50 head and neck, 16 colon, 30 liver metastases from colorectal cancer) taken before treatment. Almost all investigated tumours had folate concentrations below the median concentration required for optimal 5-FU potentiation in vitro: median levels (range, pmol/mg protein) were 3.8 (0-17.7) for head and neck, 5.8 (2.3-12.0) for colon and 12.1 (1.7-118.5) for liver metastases. Above all, these data establish the relevance of FPGS activity for predicting the efficacy of 5-FU modulated by FA or not and point to the potential clinical interest of FPGS determination in human tumours.

Mesenteric and hepatic vascular reactivity in Donryu rats with and without a cholesterol-supplemented diet

Vascular function of Donryu rats fed on a normal or cholesterol-supplemented diet was examined in the isolated perfused mesenteric arterial bed and portally perfused liver. In mesenteric preparations, frequency-dependent vasoconstriction to electrical field stimulation (4-32 Hz, 1 ms, 90 V, 30 s) and dose-dependent vasoconstriction to noradrenaline (0.15-1500 nmol) was similar in both groups. Dose-dependent vasoconstriction to alpha, beta-methylene ATP (0.05-500 nmol) via P2x purinoceptors was significantly impaired in Donryu rats fed on a cholesterol-supplemented diet. In preparations with raised tone (methoxamine 5-35 microM), there was no significant difference in endothelium-dependent relaxation to acetylcholine and ATP, or endothelium-independent relaxation to sodium nitroprusside. In liver preparations, there was no difference in frequency-dependent vasoconstriction to electrical field stimulation (2-32 Hz, 1 ms, 90 V, 30 s), or dose-dependent vasoconstriction to noradrenaline (0.05-500 nmol) and alpha, beta-methylene ATP (0.05-500 nmol) between the groups. In conclusion, in mesenteric arteries, but not in the hepatic portal vasculature of Donryu rats fed on cholesterol P2x purinoceptor function is impaired, but sympathetic neurotransmission is unaffected. Mesenteric endothelial and smooth muscle function is unimpaired.