Dehydropyrimidine Dehydrogenase Research Articles

P-186 Introduction of DYPD screening and its impact on treatment decisions: One centre's experience

Fluorouracil (5FU) forms the backbone of treatment for colorectal cancer (CRC). Dehydropyrimidine-dehydrogenase (DPD) breakdowns 5FU into inactive metabolites. Patients with genetic polymorphisms in the DYPD gene are at risk of DPD deficiency and subsequent severe toxicity. There are a number of commercially available tests for DPD deficiency but these are not standardly used in the UK. We introduced routine screening for DPD deficiency in Sheffield and present our results.

Abstract 3895: ABCC11 gene polymorphism as a potential predictive biomarker for an oral 5-fluorouracil derivative drug S-1 treatment in non-small cell lung cancer

Abstract Introduction: ABCC11/MRP8 (ABCC11) is an ATP-binding cassette transporter that is involved in regulating cellular sensitivity and resistance for many anti-cancer drugs including antifolates 5-fluorouracil (5-FU), pemetrexed and methotrexate. ABCC11 has functional genetic variant which regulate the protein expression of ABCC11. However, the relationship between the genetic variant of ABCC11 and the efficacy of anticancer drugs remains to be elucidated. An oral 5-FU derivative S-1 composed of tegafur, 5-chloro-2, 4-dihydroxypyridine (CDHP; a potent inhibitor of dehydropyrimidine dehydrogenase), and potassium oxonate, is used against non-small cell lung cancer (NSCLC) treatment; however the biomarker for S-1 is not fully examined. In this study, we examined whether ABCC11 single nucleotide polymorphism (SNP) which regulate the expression of ABCC11 is related with the efficacy of S-1. Method and results: We introduced ABCC11 showing 538G or 538A expression vector and parental plasmid into HeLa cells and established HeLa/ABCC-538G, HeLa/ABCC-538A and HeLa/mock cells, respectively. The protein expression of ABCC11 was higher in the HeLa/ABCC-538-G cell than in the other cells. Futhermore, the IC50 for 5-FU with CDHP was 0.94, 9.75 and 0.64 times higher in the HeLa, HeLa/ABCC-538G and HeLa/ABCC-538A cells than in the HeLa/mock cells, respectively. This result indicates that this ABCC11 SNP is related with 5-FU cytotxocity. Then we analyzed 21 human NSCLC cell lines, classifing NSCLC cell lines into two groups based on the genotype of the SNP 538G>A in ABCC11: a combined G/G and G/A genotype group, and an A/A genotype group. The distribution of the cytotoxicity for 5-FU in combination with CDHP was significantly lower in the A/A genotype group than in the combined G/G and G/A genotype group. Next, we examined the clinical usefulness of the ABCC11 SNP in S-1 treatment of 68 NSCLC patients. In these 68 patients, the median progression-free survival (PFS) was 73days, and the disease control rate was 50%. These data was similar to previous reports. Classified these 68 patients into each ABCC11 538G>A genotype group, we found that the disease control rate was significantly better in the A/A genotype group than in the combined G/G and G/A genotype group (A/A:59.2%, G/G and G/A:35.7%, respectively), but the PFS had no significant difference between these two genotype groups. Conclusion: SNP 538G>A in the ABCC11 gene is a potential determinant for S-1 treatment in NSCLC. Citation Format: Satoshi Fukuda, Takehiro Uemura, Tetsuya Oguri, Akira Takeuchi, Kazuki Sone, Takamitsu Asano, Yoshihiro Kanemitsu, Masaya Takemura, Hirotsugu Ohkubo, Ken Maeno, Yutaka Ito, Akio Niimi. ABCC11 gene polymorphism as a potential predictive biomarker for an oral 5-fluorouracil derivative drug S-1 treatment in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3895.

Modeling of 5-fluorouracil infulence on activity of its’ metabolic enzymes

Stashkevych M. Modeling of 5-fluorouracil infulence on activity of its’ metabolic enzymes. Journal of Education, Health and Sport. 2015;5(11):62-67. ISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.33358 http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%2811%29%3A62-67 https://pbn.nauka.gov.pl/works/666610 Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011–2014 http://journal.rsw.edu.pl/index.php/JHS/issue/archive Deklaracja. Specyfika i zawartośc merytoryczna czasopisma nie ulega zmianie. Zgodnie z informacją MNiSW z dnia 2 czerwca 2014 r., ze w roku 2014 nie bedzie przeprowadzana ocena czasopism naukowych; czasopismo o zmienionym tytule otrzymuje tyle samo punktow co na wykazie czasopism naukowych z dnia 31 grudnia 2014 r. The journal has had 5 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 1089. (31.12.2014). © The Author (s) 2015; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 05.09.2015. Revised 05.10.2015. Accepted: 30.10.2015. MODELING OF 5-FLUOROURACIL INFULENCE ON ACTIVITY OF ITS’ METABOLIC ENZYMES M. Stashkevych O. O. Bogomolets National Medical University Abstract This article presents the results of model experiment which involved intraperitoneal administration of 5-fluorouracil (5-FU) to rats with further determination of the activity of its’ key metabolic enzymes: dehydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP), in various time intervals after 5-FU injection. These results were compared to ones from the control group of animals which did not receive 5-FU. It was revealed that 5-FU has the suppressive influence on TP up to 12 hours after injection and does not affect activity of DPD. As these enzymes are responsible for 5-FU activation (TP) and degradation (DPD) the observed influence of the drug is desired effect associated with lesser toxic impact on normal cells. Keywords: 5-fluorouracil, dehydropyrimidine dehydrogenase, thymidine phosphorylase, rat liver.

647P - Impact of the Expression Levels of Fluoropyrimidine Pathway Genes on Treatment Outcomes from Adjuvant S-1 Therapy in Gastric Cancer

ABSTRACT Aim: Adjuvant S-1 therapy improves survival in patients with curatively resected gastric cancer (GC). However, little is known about the predictive or prognostic markers related to treatment outcomes from adjuvant S-1 in GC. Accordingly, we analyzed the protein and mRNA expression profiles of fluoropyrimidine pathway genes [thymidylate synthase, dehydropyrimidine dehydrogenase (DPD), thymidine phosphorylase and oroatate phosphoribosytransferase] to find markers related to treatment outcomes of adjuvant S-1. Methods: One hundred eight-four patients who had received curative gastrectomy and adjuvant S-1 were included. Immunohistochemistry (IHC) and real-time polymerase chain reaction (RT-PCR) were performed to measure the protein and mRNA levels of 4 genes from the formalin-fixed paraffin-embedded specimens. Results: In univariate analysis, low DPD protein expression in tumor (DPD IHC score Conclusions: When receiving adjuvant S-1 therapy, GC patients with high DPD expression in tumor did not have inferior outcome to those with low DPD expression. Instead, low mRNA or protein expression of DPD was related to poor DFS. Less administration of S-1 due to toxicities may have lead to this unexpected inferior treatment outcome in patients with low DPD levels. Disclosure: All authors have declared no conflicts of interest.

Phase II and gene expression analysis trial of neoadjuvant capecitabine plus irinotecan followed by capecitabine-based chemoradiotherapy for locally advanced rectal cancer: Hoosier Oncology Group GI03-53

We designed this study in locally advanced rectal cancer to determine the pathological response, toxicity, and disease-free survival (DFS) with induction capecitabine plus irinotecan followed by capecitabine-based chemoradiotherapy (CRT) and analyze the gene expression of enzymes involved in the metabolism of capecitabine and irinotecan for associations with response and toxicity. Patients with T3/T4 or node positive rectal cancer were treated with capecitabine 1,000 mg/m(2) twice daily (BID) days 1-14, and irinotecan 200 mg/m(2) on day 1 every 21 days for 2 cycles, followed by capecitabine 825 mg/m(2) BID days 1-5 per week with concurrent radiotherapy 50.4 Gy in 28 fractions. Surgical resection occurred a median of 7.4 weeks after CRT. Gene expression levels or sequencing were used to analyze carboxylesterase-converting enzymes (CES1, CES2), thymidylate synthase (TS), thymidine phosphorylase (TP), dehydropyrimidine dehydrogenase (DPD), topoisomerase I (TOPO I), and uridine-diphosphate (UDP) glucuronosyl transferase 1A1 in pre- and post-treatment tumor and normal tissue samples. Twenty-two patients were enrolled, and 18 completed neoadjuvant therapy and underwent R0 resection. Two patients with UGT1A1 7/7 had grade 3 and 4 neutropenic fever and sepsis. Pathological complete response (pCR) occurred in 6 of 18 patients (33 %) and 10 (56 %) had tumor and/or nodal downstaging. The 3-year DFS was 75.5 % (95 % CI, 39.7-91.8 %). Locoregional control rate was 100 %. We observed higher TP gene expression in pCR patients, but no correlations with toxicity. This neoadjuvant regimen was safe and demonstrated significant antitumor activity. High TP tumor gene expression was associated with obtaining pCR.

Abstract 3615: A SNP538(G>A) in ABCC11/MRP8 determines sensitivity for antimetabolites

Abstract Anti-metabolic drugs, such as 5-fluorouracil (5-FU) derivatives and antifolate drugs, such as methotrexate (MTX) and pemetrexed (MTA) are often used for widespread cancer treatment in current clinical practice. 5-FU is often used with 5-chloro-2, 4-dehydropyrimidine (CDHP) which inhibits degradation of 5-FU by inactivating dehydropyrimidine dehydrogenase (DPD) as DPD inhibitory fluoropyrimidines (DIF) in clinical because it is known that there is inverse correlation between DPD and sensitivity for 5-FU. MTA is new generation antifolate and the treatment with MTA in combination with cisplatin provides a similar efficacy, with better tolerability and more convenient administration than existing platinum doublet treatments for advanced-stage non-small-cell lung cancer (NSCLC). Because thymidylate synthase (TS) gene which expression is higher in squamous cell carcinoma compared with adenocarcinoma is considered as the most powerful molecule for resistant to MTA, MTA is only used for non-squamous cell lung cancer treatment. Thus, like DPD and TS gene, biomarkers for these anti-metabolic anti-cancer drugs are partially known. However, we can't predict the effects of these anti-metabolic drugs for cancer treatment from these biomarkers because DPD is inactivated by its inhibitor in advance and the MTA isn't used for therapy of squamous cell carcinoma in which TS expression is high. So we need to find new biomarker for anti-metabolic anti-cancer drugs which is available for clinical use. ABCC11/MRP8 (ABCC11) is one of the ATP-binding cassette (ABC) transporters which involve the resistance for some anti-cancer drugs. ABCC11 gene has a nonsynonymous SNP 538(G>A) which is important for determination of the type of human earwax that is expressed. We have previously shown that ABCC11 directly confers resistance to MTA and 5-FU by enhancing efflux of the intracellular anti-cancer drug. Therefore we examined whether ABCC11 is a predictive marker for MTA and 5-FU sensitivity in NSCLC. At first, we analyzed the relationship between the ABCC11 gene expression and IC50 for MTA or 5-FU in NSCLC cells, but there was no correlation. Next, we classified NSCLC cell lines into two groups based on the phenotype of SNP538(G>A) in ABCC11: combined G/G and G/A group and A/A group. Then we compared the distribution of the IC50 for MTA and found that the A/A group showed a significant reduction of the IC50 compared with combined G/G and G/A group in adenocarcinoma cell lines. We also compared the distribution of the IC50 for 5-FU in combination with CDHP in NSCLC cell lines and found same result. These results indicate that the SNP(538G>A) in ABCC11 gene is an important determinant for sensitivity of MTA and 5-FU under inhibition of DPD. Our results may suggest that ABCC11 SNPs is one of the biomarkers for MTA and DIF. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3615. doi:1538-7445.AM2012-3615

Abstract 3640: Increased anti-tumor effects of sequential docetaxel followed by 5-FU treatment against human oral cancer cells

Abstract [Background] Docetaxel (TXT), a novel member of the taxoid family, and 5-fluorouracil (5-FU) are key drugs against oral cancer chemotherapy. The promising clinical activity of TXT and 5-FU has promoted considerable interest in combining these drugs. Although the combination treatment has been reported to improve the response rates, sequential treatment with TXT and 5-FU was unknown. [Purpose] The aim of this study was to evaluate the anti-tumor effects of sequential treatment with TXT and 5-FU against oral squamous cell carcinoma cells. [Methods and Results] Two human oral squamous cell carcinoma cell lines, B88 and CAL27 cells were used in this study. The effects of sequential treatment on the inhibition of tumor growth with TXT and 5-FU were investigated by 3-(4, 5-dimethylthiaol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis, and the xenograft on nude mice. In vivo study, B88 or CAL cells (5×106) were subcutaneously inoculated into the backs of nude mice. When the tumor reached 0.5 cm in diameter, tumor-bearing nude mice received either the intraperitoneal administration of TXT (10 mg/kg) alone, 5-FU (15 mg/kg) alone, TXT followed by 5-FU or 5-FU followed by TXT treatment. TXT followed by 5-FU treatment more effectively inhibited the tumor growth in vitro and in vivo, and induced apoptosis than 5-FU followed by TXT treatment. To elucidate the mechanisms underlying growth inhibitory effect of TXT followed by 5-FU, we examined the expression of 5-FU metabolic enzymes, thymidylate synthase (TS), dehydropyrimidine dehydrogenase (DPD), and ortate phosphorybosyl transferase (OPRT) by real-time PCR and western blot analysis. Down-regulation of TS and DPD expression, and up-regulation of OPRT expression were induced by TXT treatment compared with 5-FU, suggesting that they enhanced the efficacy of 5-FU. [Conclusions]These findings demonstrated that sequential treatment with TXT followed by 5-FU can be effective for the patients with oral squamous cell carcinoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3640.

Evaluation of 5-fluorouracil related genes in breast cancer to predict the effect of adjuvant therapy with oral fluorouracil derivatives

New anticancer drugs have been developed, and prediction of their effect is needed to perform tailor made chemotherapy. We investigated a selection of the predictive markers for oral adjuvant chemotherapy among 5-fluorouracil (5-FU) related genes. 5-FU related genes were examined by using a laser captured microdissection and real-time RT-PCR in 220 patients with invasive breast cancer. Sixty-six patients were treated with postoperative oral fluorouracil derivatives for 12 months or more, and we examined the prognosis of these patients according to the expression of 5-FU related genes. The median of thymidylate synthase (TS), dehydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyltransferase (OPRT) mRNA values in the 220 specimens were determined for cut-off levels separating low and high gene expression. In 66 patients, 5-year disease-free survival (DFS) in the TP-high group (n=28) was significantly better than that in the TP-low group (n=38) (P=0.016). Of 220 patients, the 69 patients in TP-high group comprised 28 patients treated with oral fluorouracil derivatives and 41 patients with hormone therapy alone. The proportion of patients with lymph node involvement in the fluorouracil group was significantly greater than that in the hormone therapy alone group (P=0.003). Five-year DFS was not significantly different between the groups (P=0.80). Our results suggest that adjuvant oral fluorouracil chemotherapy may improve the prognosis of the patients with TP high expression breast cancer, and TP mRNA level in breast cancer may predict the effect of new oral fluorouracil derivatives for postoperative adjuvant chemotherapy.

Evaluation of thymidylate synthase and ERCC1 mRNA levels as predictive markers in colorectal cancer patients treated with S-1 and oxaliplatin

e15071 Background: Oxaliplatin has been widely used for the treatment of colorectal cancer. The mechanism of action of platinum compounds such as oxaliplatin is to bind to a DNA molecule in the form of a platinum-DNA-adduct. Excision repair cross complementation group 1 (ERCC1), which plays a major role in the nucleotide excision pathway, has a polymorphism in codon 118, and is reported to be associated with a resistance to platinum-based therapy. Thymidylate synthase (TS) and dehydropyrimidine dehydrogenase (DPD) are key enzymes of 5-FU metabolism and are well known to be associated with a response to 5-FU-based therapy. Methods: Twenty-one colorectal cancer patients (male:female = 7:14; median age, 65) treated with a combination of oxaliplatin and S-1 as a first-line therapy were analyzed for ERCC1 codon 118 polymorphism and the mRNA expression levels of TS, ERCC1, and DPD. Formalin-fixed paraffin- embedded surgical specimens were used and t-RNA and DNA were extracted. The mRNA expression levels were measured using real-time RT-PCR, and the polymorphism was analyzed using the allelic discrimination method together with real-time PCR. Results: No correlation was observed between ERCC1 codon118 polymorphism and any response to the chemotherapy. ERCC1 mRNA levels tended to be higher in the patients with wild-type homozygous alleles in codon 118 than in those with at least one mutant allele(1.19 vs.0.68: p= 0.15). Patients with both high TS and ERCC1 mRNA levels showed a significantly lower response rate than the others (25% vs. 67%, p=0.02). No relationship was seen between DPD mRNA expression levels and the response. Conclusions: The mRNA expression levels of TS and ERCC1 appear to be useful markers for the treatment of S-1 and oxaliplatin. No particular usefulness of ERCC1 codon 118 polymorphism was verified. No significant financial relationships to disclose.

Pilot study of combination chemotherapy of S‐1, a novel oral DPD inhibitor, and interferon‐α for advanced hepatocellular carcinoma with extrahepatic metastasis

To the authors' knowledge, there is no effective therapy for extrahepatic metastasis of hepatocellular carcinoma (HCC). In a pilot study, the results of combination therapy of S-1, a novel oral dehydropyrimidine dehydrogenase (DPD) inhibitor, and interferon-alpha (IFN-alpha) are reported for HCC patients with extrahepatic metastasis. Twelve patients with extrahepatic metastasis of HCC were enrolled in the pilot study. S-1 was administered orally at a dose based on body surface area, twice daily after a meal, for 4 weeks. IFN-alpha was injected subcutaneously on Days 1, 3, and 5 of each week. One course consisted of consecutive administration for 28 days followed by 14 days rest. An objective response was observed in 3 (25%) of 12 patients. The overall 1-year survival rate was 61.7%. Grade 3 leukocytopenia was observed in 1 patient (8.3%). No severe toxicity or treatment-related deaths were observed. The combination therapy of S-1 and IFN-alpha appears to be highly efficacious, with low toxicity in patients with extrahepatic metastases of HCC. The combination chemotherapy of oral S-1 and subcutaneous IFN-alpha is a potentially promising treatment strategy for advanced HCC with extrahepatic metastasis.

Circadian Rhythms in the CNS and Peripheral Clock Disorders: Chronopharmacological Findings on Antitumor Drugs

The effectiveness and toxicity of antitumor drugs vary depending on dosing time associated with the 24-h rhythms of biochemical, physiological, and behavioral processes under the control of the circadian clock. Such chronopharmacological phenomena are influenced by not only the pharmacokinetics but also pharmacodynamics of medications. For example, the antitumor effect and/or toxicity of irinotecan hydrochloride, interferon, and antiangiogenic agents vary depending on the dosing time associated with the 24-h rhythm of their target enzyme, receptor, protein, and pharmacokinetics. Many of them are controlled by clock genes. Chronotherapy is especially relevant when the risk and/or intensity of the symptoms of disease vary predicably over time. In a randomized multicenter trial involving patients with previously untreated metastases from colorectal cancer, the chronomodulated infusion of oxaliplatin, fluorouracil (5-FU), and folinic acid is compared with a constant-rate infusion method. Side effects such as stomatitis, peripheral sensory neuropathy are lower and the objective response is higher in the chronotherapy as compared with the fixed-rate infusion. The merit of chronomodulated infusion is supported by the 24-h rhythm of DNA synthesis and the activity of dehydropyrimidine dehydrogenase, which brings about the intracellular catabolism of 5-FU. Although interferon (IFN) also alters the clock function, the disruptive effect of IFN on clock function can be overcome by devising a dosing regimen that minimizes adverse drug effects on clock function. Thus one approach to increasing the efficiency of pharmacotherapy is the administration of drugs at times at which they are most effective and/or best tolerated.

Effectiveness of S1 after palliative gastrectomy for advanced gastric carcinoma with peritoneal metastasis

4247 Background: Since S1 reveals high response ratio for advanced gastric carcinoma, it is expected to be a promising drug for gastric carcinoma. This study was to verify the effectiveness of S1 after palliative gastrectomy for advanced gastric carcinoma with peritoneal metastasis and to evaluate the utility of thymidylate synthase and dehydropyrimidine dehydrogenase (TS/DPD) activity as an effective drug prediction of S1. Methods: Thirty-seven patients of gastric carcinoma with peritoneal metastasis inclusive of malignant ascites only, who underwent palliative resection of primary lesion, were divided into 3 groups as follows: Group A (n=13) of S1 after surgery, Group B (n=9) of chemotherapy (5FU/MTX, 5FU/MMC and 5FU only) excluding S1 after surgery, Group C (n=15) of surgery alone. The differences in clinicopathological backgrounds (age, surgical procedure, hepatic metastasis, distant lymph nodes metastasis, umber of malignant ascites only and performance status) were not recognized in the 3 groups. Survival rate and adverse effects were analyzed in all 3 groups and TS/DPD activity of Group A was investigated by RT-PCR methods. Results: The mean survival time was 505 (145–1125 days) for Group A, 447 (128–738) for Group B and 255 (63–1058) for Group C respectively. Two patients of Group A have been living without recurrence for 623 and 1125 days after the surgery. Although the significant difference was observed between Group A and Group C in survival rate (p=0.005), there was no difference between Group B and Group C. Adverse effects over Grade 3 were observed in a case of Group A (hematological toxicity), in 3 cases of Group B (2 cases of hematological toxicity and 1 case of gastrointestinal toxicity). Grade 4 toxicity was observed in neither Group A nor B. There was no statistical correlation (Pearson’s test) between survival time and TS/DPD activity (TS; p=0.055, DPD; p=0.428). Conclusions: Post-operative adjuvant S1 for the advanced gastric carcinoma with peritoneal metastasis revealed not only survival improvement but good compliance because of less adverse reactions, though TS/DPD activity was not useful as an effective drug prediction of S1. No significant financial relationships to disclose.

A phase II study of S-1 in patients with metastatic pancreatic cancer

4104 Background: The purpose of this study was to determine the efficacy and toxicity of S-1 in patients with metastatic pancreatic cancer. S-1, an oral anticancer agent, contains tegafur (FT: a prodrug of 5-fluorouracil), 5-chloro-2,4-dihydroxypyridine (CDHP: a dehydropyrimidine dehydrogenase inhibitor), and potassium oxonate (Oxo: an orotate phosphoribosyl transferase inhibitor) at a molar ratio of FT:CDHP:Oxo = 1:0.4:1. Methods: Patients with histologically or cytologically confirmed, bidimensionally measurable metastatic pancreatic adenocarcinoma not amenable to surgery or radiotherapy were eligible for the study. Other eligibility criteria included a Karnofsky performance status of 80 to 100%; an age of 20 to 74 years; adequate hematological, renal and liver functions; no prior chemotherapy; and written informed consent. S-1 was administered orally (40 mg/m2) b.i.d. for 28 consecutive days, repeated every 6 weeks. Patients continued to receive additional courses of S-1 until disease progression or the appearance of unacceptable toxicity. Results: Forty-one patients from seven institutions were enrolled between January 2003 and April 2004. One patient deteriorated before receiving treatment and was excluded from further analysis. Out of the 40 eligible patients, 15 patients had partial responses, for an objective response rate of 37.5% (95% c.i.: 22.7 - 54.2%); 11 patients had no change, 13 had progressive diseases, and the final patient was not evaluated. The median survival time was 8.8 months (95% c.i.: 7.5 - 10.8 months). A clinical benefit response was achieved in four of the ten evaluable patients. The main grade 3 - 4 toxicities were neutropenia (12.5%), anorexia (12.5%), diarrhea (7.5%) and nausea (7.5%). Other grade 3 - 4 toxicities, like vomiting, disseminated intravascular coagulation, colitis, hypotension, jaundice and liver dysfunctions, were less frequent. Conclusions: S-1 is active and well tolerated as a single agent chemotherapy in patients with metastatic pancreatic cancer. A prospective randomized trials evaluating S-1 monotherapy is warranted. No significant financial relationships to disclose.

Late phase II study of S-1 in patients with taxane resistant breast cancer

745 Background: S-1 is a novel oral anticancer agent, contains tegafur (FT: prodrug of 5-fluorouracil), 5-chloro-2,4-dihydroxypyridine (CDHP: dehydropyrimidine dehydrogenase inhibitor), and potassium oxonate (Oxo: orotate phosphoribosyl transferase inhibitor) at a molar ratio of FT:CDHP:Oxo = 1:0.4:1. We conducted this study to evaluate the efficacy and safety of S-1, in patients (pts) with taxane resistant breast cancer (BC). Methods: Eligibility criteria were as follows: informed consent was obtained, age >=20 to <75, had histologicaly confirmed BC, had metastatic BC, had received one or two prior chemotherapeutic regimens one of which had to have contained paclitaxel or docetaxel, progression or relapse was confirmed within 6 months after taxane treatment, has one or more measurable region, has adequate organ function, PS 0–2, life expectancy more then 3 months. S-1 was given orally at 40mg/m2 b.i.d. for 28 consecutive days followed by 14 days rest period and repeated in 42 day cycles. The cycles were continued until disease progressed. Results: Between November 2001 and April 2003, 56 pts were registered on the trial, and 55 pts received treatment with S-1. All pts had received taxane treatment, and 40 (72.7%) of 55 pts had received anthracycline containing chemotherapy. Response was evaluated based on RECIST criteria at independent review committee. Twelve (21.8%) of the 55 pts (95% CI 11.8 – 35.0%) were confirmed partial responders and there was no complete responder. The median overall survival period was 470 days (Follow-up is being continued). The grade (G) 4 treatment-related adverse event (AE) wasn't observed. The most common G3 treatment-related AEs were neutoropenia (10.9%), leucopenia (9.1%), diarrhea (5.5%) and anorexia (5.5%). There was no G3–4 hand-foot syndrome, even G2 was 5.5%. Almost all AEs were manageable with brief drug interruption or dose reduction. Conclusions: S-1 is an active drug in the treatment of taxane resistant BC and has favorable toxicity profiles. No significant financial relationships to disclose.

Late phase II study of S-1 in patients with taxane resistant breast cancer

745 Background: S-1 is a novel oral anticancer agent, contains tegafur (FT: prodrug of 5-fluorouracil), 5-chloro-2,4-dihydroxypyridine (CDHP: dehydropyrimidine dehydrogenase inhibitor), and potassium oxonate (Oxo: orotate phosphoribosyl transferase inhibitor) at a molar ratio of FT:CDHP:Oxo = 1:0.4:1. We conducted this study to evaluate the efficacy and safety of S-1, in patients (pts) with taxane resistant breast cancer (BC). Methods: Eligibility criteria were as follows: informed consent was obtained, age >=20 to <75, had histologicaly confirmed BC, had metastatic BC, had received one or two prior chemotherapeutic regimens one of which had to have contained paclitaxel or docetaxel, progression or relapse was confirmed within 6 months after taxane treatment, has one or more measurable region, has adequate organ function, PS 0–2, life expectancy more then 3 months. S-1 was given orally at 40mg/m2 b.i.d. for 28 consecutive days followed by 14 days rest period and repeated in 42 day cycles. The cycles were continued until disease progressed. Results: Between November 2001 and April 2003, 56 pts were registered on the trial, and 55 pts received treatment with S-1. All pts had received taxane treatment, and 40 (72.7%) of 55 pts had received anthracycline containing chemotherapy. Response was evaluated based on RECIST criteria at independent review committee. Twelve (21.8%) of the 55 pts (95% CI 11.8 – 35.0%) were confirmed partial responders and there was no complete responder. The median overall survival period was 470 days (Follow-up is being continued). The grade (G) 4 treatment-related adverse event (AE) wasn't observed. The most common G3 treatment-related AEs were neutoropenia (10.9%), leucopenia (9.1%), diarrhea (5.5%) and anorexia (5.5%). There was no G3–4 hand-foot syndrome, even G2 was 5.5%. Almost all AEs were manageable with brief drug interruption or dose reduction. Conclusions: S-1 is an active drug in the treatment of taxane resistant BC and has favorable toxicity profiles. No significant financial relationships to disclose.

Quantitative gene expression analysis of thymidylate synthase, thymidine phosphorylase, and dehydropyrimidine dehydrogenase in rectal cancer: correlation with histopathological tumor regression after neoadjuvant radiochemotherapy

Quantitative gene expression analysis of thymidylate synthase, thymidine phosphorylase, and dehydropyrimidine dehydrogenase in rectal cancer: correlation with histopathological tumor regression after neoadjuvant radiochemotherapy

Étude des variations circadiennes de l’activité de la dihydropyrimidine déshydrogénase (DPD) dans la muqueuse buccale chez des sujets volontaires sains

Dehydropyrimidine dehydrogenase (DPD) is the rate limiting enzyme of 5-fluoro-uracil (5-FU) catabolism. DPD rhythmicity, peak at 1:00 is an important determinant of 5-FU tolerability and has practical implications for the pattern of chronomodulated delivery of the drog. Maximal tolerated doses have been highed and anti-tumour activityalso. But 30% patients have toxicities expressed by mucositis in oral mucosa. Purpose. – Titrate DPD activity in oral mucosa in healthy subjects, in oral mucosa which is the target of 5-FU, at 10:00 and midnight could help to understand toxicities in patients. Subjects and methods. – Eight healthy subjects participated (information note signed by patients). One oral mucosa sample was drawn at 10:00 and an other at midnight. DPD activity was analyzed by a H.P.L.C. method. Results. – DPD activity in oral mucosa varied from 0.004 to 0.13 nmol min –1 mg –1 prot at 10:00 and from 0.07 to 0.16 nmol min –1 mg –1 prot at midnight, with a 30% average relative increase from morning to midnight (range: –20% to +100%; statistical significant difference with P <0.073). Conclusion. – DPD circadian changes in healthy oral mucosa subjects remained to agree to mononuclear cell, with increase at midnight.

Changes in toxicity and effectiveness with timing of drug administration: implications for drug safety.

The effectiveness and toxicity of many drugs can vary depending on the time of administration in relation to 24-hour rhythms of biochemical, physiological and behavioural processes under the control of the circadian clock. Such chronopharmacological phenomena are influenced by not only the pharmacokinetics but also pharmacodynamics of medications. Chronotherapy is especially relevant when the risk and/or intensity of the symptoms of disease vary predictably over time as exemplified by allergic rhinitis, arthritis, asthma, myocardial infarction, congestive heart failure, stroke and peptic ulcer disease. Morning, once-daily administration of corticosteroids results in little adrenocortical suppression, while the same daily dose split into four equal doses to coincide with daily meals and bedtime results in significant hypothalamus-pituitary-adrenal axis suppression. In a randomised, multicentre trial involving patients with previously untreated metastases from colorectal cancer, the chronomodulated infusion of oxaliplatin, fluorouracil and folinic acid was compared with a constant-rate infusion method. Adverse effects such as stomatitis and peripheral sensory neuropathy were lower and objective response was higher with chronotherapy as compared with the fixed-rate infusion. The merit of chronomodulated infusion is supported by the 24-hour rhythm of DNA synthesis and the activity of dehydropyrimidine dehydrogenase, which brings about the intracellular catabolism of fluorouracil. On the other hand, haloperidol and selective serotonin reuptake inhibitors have diverse effects on sleep continuity and nocturnal arousals. Although interferon also alters the clock function, this disruptive effect can be overcome by devising an administration regimen that minimises adverse drug effects on clock function. Thus, one approach to increasing the efficiency of pharmacotherapy is the administration of drugs at times at which they are most effective and/or best tolerated.

Modulation of intracellular glutathione concentration alters dehydropyrimidine dehydrogenase activity in peripheral blood mononuclear cells

Dehydropyrimidine dehydrogenase (DPD) is the initial key enzyme in the regulation of 5-fluorouracil catabolism and thus controls availability of 5-fluorouracil for anabolism. Modulation of DPD activity may increase the antitumor effect and avoid toxic side effects in 5-fluo-rouracil-based chemotherapy. We measured DPD activity in peripheral blood mononuclear cells from cancer patients and simultaneously monitored intracellular glutathione (GSH) and plasma GSH levels. There was a significant linear relationship between DPD activity and intracellular GSH levels in peripheral blood mononuclear cells obtained from cancer patients. Suppression of intracellular GSH level by buthionine sulfoximine decreased DPD activity, while enhancement of intracellular GSH level by 2-mercaptoethanol increased DPD activity. This study indicated that alteration of intracellular GSH concentration may modulate DPD activity.

Dihydropyrimidine Dehydrogenase Enzyme Deficiency: Clinical and Genetic Assessment of Prevalence in Turkish Cancer Patients

Background: Fluorouracil has been reported to induce severe side-effects in particular subjects who have deficiency in dehydropyrimidine dehyrogenase activity, the major enzyme in the catabolism of fluorouracil.Patients and methods: In this study, we aimed to analyze the heterozygote and homozygote frequencies of dehydropyrimidine dehyrogenase gene mutation in 200 patients receiving fluorouracil based chemotherapy together with the assessment of the toxicity profile of these chemotherapy regimens.Results: According to the results of clinical toxicity assessments, grade 3–4 hematologic toxicity was noted in 12% of the patients. Grade 3 gastrointestinal toxicity was present in 5% of the subjects with no grade 4 side effects. The heterozygote (2q(1−q)) and homozygote (q2) frequencies of dehydropyrimidine dehyrogenase gene mutation were calculated as 1.5% (3/200) and 0.000055% (1/18,043) in the analyzed samples.Conclusion: In this report, for the first time we documented the frequency of dehydropyrimidine dehydrogenase gene mutation in Turkish cancer patients. The determination of enzyme activity in suspected individuals and analysis of other mutations on a population basis would be the next steps for our country.