gimeracil and doxifluridine

Doxifluridine (DF), an oral 5-FU prodrug, has been used for various solid cancers due to its efficacy and low toxicity. We aim to evaluate the effect of DF as adjuvant monotherapy in advanced gastric cancer.. We retrospectively reviewed the clinical data of 263 patients with advanced gastric cancer who underwent curative gastrectomy between January 2010 and December 2013 at our institute. Since previous randomized control trials have confirmed the efficacy of S-1 as adjuvant chemotherapy in advanced gastric cancer, we analyzed the oncologic effect and patient compliance of the DF group compared to the S-1 group. After propensity score matching, 48 patients were included in each group.. There was no significant difference in 5-year overall survival (OS) and 5-year disease-free survival (DFS) between DF and S-1 groups (5-year OS; 77.1% vs 75.0%; p = 0.729, 5-year DFS; 76.6% vs 73.9%; p = 0.748). The completion rates of the DF and S-1 groups were 60.4% and 72.9%, respectively (p = 0.194). The mean relative dose intensity of the DF and S-1 groups were 76.2% and 84.2%, respectively (p = 0.195). After multivariate analysis, the chemotherapy regimen was not a risk factor for OS and DFS, whereas relative dose intensity and pathologic stage were independent prognostic factors.. There was no significant difference in the oncologic effect and patient compliance between DF and S-1 groups. DF could be an alternative option for adjuvant chemotherapy in advanced gastric cancer. In addition, we confirmed that relative dose intensity is an important independent prognostic factor for survival.

Topics: Antineoplastic Combined Chemotherapy Protocols; Chemotherapy, Adjuvant; Gastrectomy; Humans; Neoplasm Staging; Oxonic Acid; Propensity Score; Retrospective Studies; Stomach Neoplasms; Tegafur

The purposes of this study were to evaluate the antitumor activity of S-1 (1 M tegafur, 0.4 M 5-chloro-2,4-dihydroxypyridine and 1 M potassium oxonate) on human lung tumor xenografts, as compared with other fluoro-pyrimidines, and to investigate the relationships between fluoropyrimidine antitumor activities and four distinct enzymatic activities involved in the phosphorylation and degradation pathways of 5-fluorouracil (5-FU) metabolism. S-1, UFT (1 M tegafur-4 M uracil), 5'-deoxy-5-fluorouridine (5'-DFUR), capecitabine and 5-FU were administered for 14 consecutive days to nude mice bearing lung tumor xenografts. S-1 showed stronger tumor growth inhibition in four of the seven tumors than the other drugs. Cluster analysis, on the basis of antitumor activity, indicated that S-1/UFT and 5'-DFUR/capecitabine/5-FU could be classified into another group. We investigated tumor thymidylate synthase content, dihydropyrimidine dehydrogenase (DPD) activity, thymidine phosphorylase (TP) activity and orotate phosphoribosyl transferase activity in seven human lung tumor xenografts and performed regression analyses for the antitumor activities of fluoropyrimidines. There were inverse correlations between antitumor and DPD activities for 5'-DFUR (r=-0.79, P=0.034), capecitabine (r=-0.56, P=0.19) and 5-FU (r=-0.86, P=0.013). However, no such correlations were observed for S-1 and UFT. These findings suggest that S-1 containing a potent DPD inhibitor may have an antitumor effect on lung tumors, with high basal DPD activity, superior to those of other fluoropyrimidines.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Capecitabine; Cell Line, Tumor; Deoxycytidine; Dihydrouracil Dehydrogenase (NADP); Floxuridine; Fluorouracil; Humans; Lung Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Orotate Phosphoribosyltransferase; Oxonic Acid; Pyridines; Tegafur; Thymidine Phosphorylase; Treatment Outcome; Uracil; Xenograft Model Antitumor Assays

Capecitabine, an anticancer prodrug, is thought to be biotransformed into active 5-fluorouracil (5-FU) by three enzymes. After oral administration, capecitabine is first metabolized to 5'-deoxy-5-fluorocytidine (5'-DFCR) by carboxylesterase (CES), then 5'-DFCR is converted to 5'-deoxy-5-fluorouridine (5'-DFUR) by cytidine deaminase. 5'-DFUR is activated to 5-FU by thymidine phosphorylase. Although high activities of drug metabolizing enzymes are expressed in human liver, the involvement of the liver in capecitabine metabolism is not fully understood. In this study, the metabolism of capecitabine in human liver was investigated in vitro. 5'-DFCR, 5'-DFUR, and 5-FU formation from capecitabine were investigated in human liver S9, microsomes, and cytosol in the presence of the inhibitor of dihydropyrimidine dehydrogenase, 5-chloro-2,4-dihydroxypyridine. 5'-DFCR, 5'-DFUR, and 5-FU were formed from capecitabine in cytosol and in the combination of microsomes and cytosol. Only 5'-DFCR formation was detected in microsomes. The apparent K(m) and V(max) values of 5-FU formation catalyzed by cytosol alone and in combination with microsomes were 8.1 mM and 106.5 pmol/min/mg protein, and 4.0 mM and 64.0 pmol/min/mg protein, respectively. The interindividual variability in 5'-DFCR formation in microsomes and cytosol among 14 human liver samples was 8.3- and 12.3-fold, respectively. Capecitabine seems to be metabolized to 5-FU in human liver. 5'-DFCR formation was exhibited in cytosol with large interindividual variability, although CES is located in microsomes in human liver. In the present study, it has been clarified that the cytosolic enzyme would be important in 5'-DFCR formation, as is CES.

Topics: Antimetabolites, Antineoplastic; Capecitabine; Cytosol; Deoxycytidine; Dihydrouracil Dehydrogenase (NADP); Floxuridine; Fluorouracil; Humans; In Vitro Techniques; Microsomes, Liver; Prodrugs; Pyridines; Thymidine Phosphorylase