256 resultados para 5-fluorouracil

em Queensland University of Technology - ePrints Archive


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Background: Hydroxyurea (HU), an inhibitor of ribonucleotide reductase, may potentiate the activity of 5-fluorouracil (5-FU) and folinic acid (FA) by reducing the deoxyribonucleotide pool available for DNA synthesis and repair. However as HU may inhibit the formation of 5-fluoro-2-deoxyuridine-5- monophosphate (FdUMP), one of the principal active metabolites of 5-FU, the scheduling of HU may be critical. In vitro experiments suggest that administration of HU following 5-FU, maintaining the concentration in the region of I mM for six or more hours, significantly enhances the efficacy of 5-FU. Patients and methods: 5-FU/FA was given as follows: days 1 and 2 - FA 250 mg/m 2 (max. 350 mg) over two hours followed by 5-FU 400 mg/m 2 by intravenous bolus (ivb) over 15 minutes and subsequently 5-FU 400 mg/m 2 infusion (ivi) over 22 hours. HU was administered on day 3 immediately after the 5-FU with 3 g ivb over 15 minutes followed by 12 g ivi over 12 hours. Results: Thirty patients were entered into the study. Median survival was nine months (range 1-51 + months). There were eight partial responses (28%, 95% CI: 13%-47%). The median duration of response was 6.5 (range 4-9 months). Grade 3-4 toxicities included neutropenia (grade 3 in eight patients and grade 4 in five), anaemia (grade 3 in one patient) and diarrhoea (grade 3 in two patients). Neutropenia was associated with pyrexia in two patients. Phlebitis at the infusion site occurred in five patients. The treatment was complicated by pulmonary embolism in one patient and deep venous thrombosis in another. Conclusion: HU administered in this schedule is well tolerated. Based on these results and those of other phase II studies, a randomised phase III study of 5-FU, FA and HU versus 5-FU and FA using the standard de Gramont schedule is recommended.

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Objective To evaluate the efficacy and toxicity of Oxaliplatin and 5-Fluorouracil (5-FU)/Leucovorin (LV) combination in ovarian cancer relapsing within 2 years of prior platinum-based chemotherapy in a phase II trial. Methods Eligible patients had at least one prior platinum-based chemotherapy regimen, elevated CA-125 ≥ 60 IU/l, radiological evidence of disease progression and adequate hepatic, renal and bone marrow function. Patients with raised CA-125 levels alone as marker of disease relapse were not eligible. Oxaliplatin (85 mg/m 2) was given on day 1, and 5-Fluorouracil (370 mg/m 2) and Leucovorin (30 mg) was given on days 1 and 8 of a 14-day cycle. Results Twenty-seven patients were enrolled. The median age was 57 years (range 42-74 years). The median platinum-free interval (PFI) was 5 months (range 0-17 months) with only 30% of patients being platinum sensitive (PFI > 6 months). Six patients (22%) had two prior regimens of chemotherapy. A total of 191 cycles were administered (median 7; range 2-12). All patients were evaluable for toxicity. The following grade 3/4 toxicities were noted: anemia 4%; neutropenia 15%; thrombocytopenia 11%; neurotoxicity 8%; lethargy 4%; diarrhea 4%; hypokalemia 11%; hypomagnesemia 11%. Among 27 enrolled patients, 20 patients were evaluable for response by WHO criteria and 25 patients were evaluable by Rustin's CA-125 criteria. The overall response rate (RR) by WHO criteria was 30% (95% CI: 15- 52) [three complete responses (CRs) and three partial responses (PRs)]. The CA-125 response rate was 56% (95% CI: 37-73). Significantly, a 25% (95% CI: 9-53) radiological and a 50% (95% CI: 28-72) CA-125 response rate were noted in platinum resistant patients (PFI < 6 months). The median response duration was 4 months (range 3-12) and the median overall survival was 10 months. Conclusion Oxaliplatin and 5-Fluorouracil/ Leucovorin combination has a good safety profile and is active in platinum-pretreated advanced epithelial ovarian cancer. © 2004 Elsevier Inc. All rights reserved.

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Background The combination chemotherapy regimen of streptozocin and 5-fluorouracil (FU/STZ) has been used for the treatment of metastatic neuroendocrine tumours. Aim The aim of this study was to analyse the use of this regimen in a tertiary oncology referral centre over a 10-year period. Method We retrospectively analysed nine cases from February 2000 to May 2010. Patient demographics, chemotherapy schedule, toxicities, progression-free and overall survival were tabulated for each patient. Result The median progression-free survival was 17 months (range 3-48+ months), and overall survival 31 months (range 12-53+ months) with no toxicity related deaths. Conclusion FU/STZ was a well-tolerated regimen that produced significant benefit in the setting of metastatic and progressive disease. Our case series demonstrated comparable progression-free survival and overall survival in relation to randomized controlled studies and previous case series. © Royal Academy of Medicine in Ireland 2011.

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Cisplatin and carboplatin are active in previously untreated patients with metastatic breast cancer (MBC) with mean response rates (RRs) of 50 and 32%, respectively. In pretreated patients the RR to cisplatin/carboplatin monotherapy declines markedly to <10%. Cisplatin and carboplatin have been combined with many other cytotoxics. In first-line setting high activity has been observed in combination with taxanes or vinorelbine (RRs consistently ∼60%). It appears that these newer combinations are superior to older regimens with etoposide (RRs 30 to 50%) or 5-fluorouracil (RRs 40 to 60%). Cisplatin-/carboplatin-based regimens with infusional 5-FU and epirubicin/paclitaxel/vinorelbine achieve high RRs of around 60 to 80%. However these regimens are difficult to administer in all patients because they require central venous access for continuous 5-FU infusion. In pretreated MBC the combinations of cisplatin-taxane/vinorelbine/gemcitabine or carboplatin-docetaxel/vinorelbine yield RRs of 40 to 50%, which are higher than those achieved with platinum-etoposide/5-FU. In locally advanced disease cisplatin-based regimens achieve very high RRs (>80%). This would suggest that in chemotherapy-naïve patients platinum-based therapy might have an important role to play. Additionally the synergy demonstrated between platinum compounds, taxanes and herceptin, in preclinical and clinical studies is of immense importance and the results of the two ongoing Breast Cancer International Research Group randomized phase III studies are eagerly awaited. These studies may help clarify the role of platinum compounds in the treatment of metastatic and possibly early breast cancer. © 2003 Elsevier Ltd. All rights reserved.

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Growth and metastatic spread of invasive carcinoma depends on angiogenesis, the formation of new blood vessels. Platelet-derived endothelial cell growth factor (PD-ECGF) is an angiogenic growth factor for a number of solid tumors, including lung, bladder, colorectal, and renal cell cancer. Cervical intraepithelial neoplasia (CIN) is the precursor to squamous cell cervical carcinoma (SCC). Mean vessel density (MVD) increases from normal cervical tissue, through low- and high-grade CIN to SCC. We evaluated PD-ECGF immunoreactivity and correlated its expression with MVD in normal, premalignant, and malignant cervical tissue. PD-ECGF expression was assessed visually within the epithelial tissues and scored on the extent and intensity of staining. MVD was calculated by counting the number of vessels positive for von Willebrand factor per unit area subtending normal or CIN epithelium or within tumor hotspots for SCC. Cytoplasmic and/or nuclear PD-ECGF immunoreactivity was seen in normal epithelium. PD-ECGF expression significantly increased with histologic grade from normal, through low- and high-grade CIN, to SCC (P < .02). A progressive significant increase in the microvessel density was also seen, ranging from a mean of 28 vessels for normal tissue to 57 for SCC (P < .0005). No correlation was found between PD-ECGF expression and MVD (P = .45). We conclude that PD-ECGF expression and MVD increase as the cervix transforms from a normal to a malignant phenotype. PD-ECGF is thymidine phosphorylase, a key enzyme in the activation of fluoropyrimidines, including 5-fluorouracil. Evaluation of PD-ECGF thymidine phosphorylase expression may be important in designing future chemotherapeutic trials in cervical cancer. Copyright (C) 2000 by W.B. Saunders Company.

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Purpose: Although oral fluoropyrimidine pro-drugs are increasingly being administered in preference to intravenous nucleoside analogues in cancer chemotherapy, their activation in malignant liver tissue may be insufficient. OGT 719 (1-galactopyranosyl-5-fluorouracil) is a novel nucleoside analogue, preferentially localized in hepatocytes and hepatoma cells via the asialoglycoprotein receptor. The aim of this study was to assess the systemic bioavailability of this rationally designed drug in 16 patients with advanced solid cancers. Method: Crossover pharmacokinetic study of oral (400 or 800 mg) and intravenous (250 mg/m 2) OGT 719. Results: Linear pharmacokinetics and oral bioavailability of approximately 25% were observed at the dose levels used in this study. Like other 5-FU prodrugs, considerable interpatient variability was observed in bioavailability following oral dosing. The mean half-life for oral doses was 4 h. OGT 719 was well tolerated. No objective tumour responses were demonstrated. Conclusion: The systemic bioavailability and half-life of oral OGT 719 are sufficient to merit dose escalation studies with frequent daily dosing. Subsequent efficacy studies should be performed in patients with primary and secondary liver malignancies.

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Purpose: Although oral fluoropyrimidine pro-drugs are increasingly being administered in preference to intravenous nucleoside analogues in cancer chemotherapy, their activation in malignant liver tissue may be insufficient. OGT 719 (1-galactopyranosyl-5-fluorouracil) is a novel nucleoside analogue, preferentially localized in hepatocytes and hepatoma cells via the asialoglycoprotein receptor. The aim of this study was to assess the systemic bioavailability of this rationally designed drug in 16 patients with advanced solid cancers. Method: Crossover pharmacokinetic study of oral (400 or 800 mg) and intravenous (250 mg/m 2) OGT 719. Results: Linear pharmacokinetics and oral bioavailability of approximately 25% were observed at the dose levels used in this study. Like other 5-FU prodrugs, considerable interpatient variability was observed in bioavailability following oral dosing. The mean half-life for oral doses was 4 h. OGT 719 was well tolerated. No objective tumour responses were demonstrated. Conclusion: The systemic bioavailability and half-life of oral OGT 719 are sufficient to merit dose escalation studies with frequent daily dosing. Subsequent efficacy studies should be performed in patients with primary and secondary liver malignancies.

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Background The MAGIC/UK Medical Research Council (MRC) trial set the standard of care for treatment of resectable gastric and junctional adenocarcinoma, demonstrating that perioperative chemotherapy with epirubicin, cisplatin and 5-fluorouracil (ECF) confers a survival benefit over surgery alone. The randomized ECF for advanced and locally advanced esophagogastric cancer (REAL-2) trial showed that, in the metastatic setting, the EOX regimen (epirubicin, oxaliplatin and capecitabine) is as effective as ECF, with a favourable toxicity profile. Methods Consecutive patients with resectable gastric or junctional adenocarcinoma treated with perioperative EOX, between 2007 and 2012, were retrospectively analysed. Results Fifty-nine patients (12 female, 47 male), commenced EOX therapy; 47 underwent surgery. A good pathological response was seen in 34 %, (16/47). Disease recurrence occurred in 19 patients (19/47, 40 %). Median overall survival was 22 months, with 4-year survival of 47 %. Chemotoxicities were consistent with those previously reported for this regimen. Conclusion This study in a high-volume centre demonstrates that EOX in resectable gastric and junctional adenocarcinoma is associated with a reasonable safety profile, and efficacy consistent with that reported for ECF.

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Thymine DNA glycosylase (TDG) functions in base excision repair, a DNA repair pathway that acts in a lesion-specific manner to correct individual damaged or altered bases. TDG preferentially catalyzes the removal of thymine and uracil paired with guanine, and is also active on 5-fluorouracil (5-FU) paired with adenine or guanine. The rs4135113 single nucleotide polymorphism (SNP) of TDG is found in 10% of the global population. This coding SNP results in the alteration of Gly199 to Ser. Gly199 is part of a loop responsible for stabilizing the flipped abasic nucleotide in the active site pocket. Biochemical analyses indicate that G199S exhibits tighter binding to both its substrate and abasic product. The persistent accumulation of abasic sites in cells expressing G199S leads to the induction of double-strand breaks (DSBs). Cells expressing the G199S variant also activate a DNA damage response. When expressed in cells, G199S induces genomic instability and cellular transformation. Together, these results suggest that individuals harboring the G199S variant may have increased risk for developing cancer.