5FU Dose Research Articles

A phase I trial of isolated hepatic perfusion (IHP) using 5-FU and oxaliplatin in patients with unresectable isolated liver metastases (ILM) from colorectal cancer (CRC).

283 Background: IHP is a proven approach for regional delivery of chemotherapy in patients with unresectable ILM. This study sought to determine safety and MTD of administering 5FU in combination with fixed dose oxaliplatin via IHP. Methods: Prospective Phase I dose escalation with standard 3x3 dosing. Subjects with unresectable ILM from CRC scheduled to receive an HAI pump were eligible. IHP employed fixed dose oxaliplatin (previously established)with escalating doses of 5FU. 1 endpoint was to determine MTD for this combination. 2 endpoints were response to IHP alone, PFS, and OS for IHP + HAI-FUDR. Systemic and IHP plasma PK of 5FU, anabolites, total, and free platinum were determined by validated assays. Results: Between Aug 2007 - Mar 2011, 11 subjects were enrolled. All patients received at least one line of pre-IHP systemic chemotherapy. There were 4 Grade 3 SAE (36.3%) and no grade 4 events. 2 DLTs occurred in the second dose cohort of 300mg/m2. Dose escalation was terminated and 200mg/m2 5FU was determined to be the MTD. There was 1 DLT in the dose de-escalating phase of 200mg/m2. At first follow-up, 9 pts (82%) had a partial response, while 2 (18%) had stable disease. 64% of pts had a >50% decrease in CEA level. Actuarial 1 and 2 year survival was 100% and 75% respectively, with median follow-up of 23 mos. IHP exposures (AUC0-60min) were 10.9±4.5 µgPt·h/mL (platinum), 49.3±30.7 µg·h/mL 5FU (DL1) and 70.5±35.5 µg·h/mL 5FU (DL2). Free platinum represented 82±14% of total platinum. Systemic exposure (AUC0-inf) relative to IHP exposure was negligible for both total platinum (1.1±1.5%) and 5FU (0.09±0.10%). IHP exposure to metabolites relative to 5FU was 4.9±2.5% for FUrd and 0.23±0.14% for FdUrd, respectively. Conclusions: MTD for IHP with 5FU and oxaliplatin is 200 mg/m2 and 40mg/m2 respectively. Systemic exposure to the agents was minimal. The response and survival observed in this dose escalation study warrants assessment in a larger phase II trial. [Table: see text]

Cytopenia induction by 5-fluorouracil identifies thrombopoietic mutants in sensitized ENU mutagenesis screens

The ability of random mutagenesis techniques to annotate the mammalian genome can be hampered due to genetic redundancy and compensatory pathways that mask heterozygous mutations under homeostatic conditions. The objective of this study was to devise a pharmacologically sensitized screen using the chemotherapeutic drug, 5-fluorouracil (5FU), to induce cytopenia. 5FU dose was optimized in the 129/SvImJ, C57BL/6J, BALB/cJ, and C3H/HeJ strains of laboratory mice. N-ethyl-N-nitrosourea (ENU) mutagenesis was performed on 129/SvImJ males and phenotypic variants were identified by backcrossing on to the C57BL/6J background. G1 animals were challenged with 100 μg/g 5FU and phenodeviants with altered platelet recovery were monitored. Of 546 G1 animals tested, 15 phenodeviants were identified that displayed increased baseline platelet number, a platelet overshoot, or delayed platelet recovery, thereby demonstrating the utility of this approach for uncovering mutations in megakaryocyte and platelet development. Four G1 mice were selected for further analysis. The phenotypes were heritable in all four strains and genetic mapping identified a chromosome location in two of the three G2 lines tested. In conclusion, our group has developed a sensitized random mutagenesis screen utilizing 5FU and has shown that the strain combination of 129/SvImJ × C57BL/6J is robust for identification of founder lines with defects in megakaryocyte and platelet development.

Uridine triacetate for prevention of 5FU toxicity due to dihydropyrimidine dehydrogenase (DPD) deficiency.

e19560 Background: Dihydropyrimidine dehydrogenase (DPD) catalyzes degradation of 5-fluorouracil (5FU). Patients with complete or partial DPD deficiency (0.1 and 3% of the population, respectively) can experience severe or lethal toxicities to 5FU, and impaired clearance may underlie many of the 1300 US 5FU toxicity deaths each year. Uridine triacetate prevents or diminishes toxicities when orally administered after 5FU overexposure, and has been used successfully as an investigational antidote in >50 patients following accidental overdoses. Methods: A colorectal cancer patient experienced Grade 3 and 4 GI and hematologic toxicities after a 96 hour infusion of 1000 mg/m2 5FU and was found to be DPD deficient (double mutation). The patient subsequently tolerated 50 and 100 mg 5FU bolus treatments in a modified FOLFOX regimen. However, during the second cycle, this DPD-deficient patient inadvertently received 1000 mg 5FU in 1 minute. Life-threatening toxicity was expected. Treatment with uridine triacetate (10 g q6h for 20 total doses) began within 8 hours. Results: In marked contrast to his first exposure to 5FU, the patient experienced no mucositis or additional cytopenia. Preclinical and mechanistic data predicted and support this observation. In a mouse model of DPD deficiency using ethynyluracil (2 mg/kg i.p.), a standard therapeutic 5FU dose of 100 mg/kg i.p. was lethal. Treatment with oral uridine triacetate (2 g/kg t.i.d. x 5 d) starting 2, 24 or 72 hours after 5FU resulted in 100%, 80% or 70% survival, respectively. Conclusions: Timely treatment with uridine triacetate appeared to prevent severe 5FU toxicity in a DPD-deficient patient and reduced mortality in DPD-inhibited mice receiving 5FU. Uridine triacetate has been shown previously to protect patients (and mice) from 5FU toxicities following 5FU overdose. Therefore, DPD-deficient patients who have received 5FU should also benefit from uridine triacetate treatment if the overexposure is identified soon enough after 5FU dosing. Therapeutic monitoring of 5FU during or after infusions would permit rapid detection of 5FU overexposure due to DPD-deficiency or other clearance defects, enabling the use of uridine triacetate as a potential antidote.

FOLFIRI followed by radiochemotherapy and surgery in locally advanced gastric cancer: FFCD 0308 phase II trial.

4108 Background: In locally advanced gastric cancer, perioperative chemotherapy (CT) is often recommended. The chemoradiotherapy (CTRT) interest is supported by the high risk of regional recurrence. The aim of this trial was to assess the feasibility of complete treatment (CT+CTRT+surgery) with a CT regimen efficient and well tolerated in metastatic phase. Methods: Histologically proven gastric carcinoma, with T3 and or N+, M0 according to CTscan or endoscopic ultrasound, WHO status ≤ 1 and allowing major surgery were eligible in this phase II multicenter study. The treatment consisted of 4 courses of FOLFIRI followed by concomitant CTRT (45 Gy at 1.8 Gy per fraction in 5 weeks, 5FU 200 mg/mg2 days 1 to 5 each week of radiotherapy), followed by surgical resection with partial or total gastrectomy according to the localization of the tumor 30 days after, with D1 or D2 lymphadenectomy. A complete treatment was defined by full CT courses, at least 22.5 fractions of RT (90% fractions) and 75% of the 5FU dose, followed by at least surgical exploration. A feasibility rate of 70% was considered uninteresting, 88% being expected. A Fleming two stages design required more than 34 complete treatments in 42 pts to assert the treatment feasibilty (unilateral alpha 5%, power 83%). Analyses were performed in intent to treat. Results: The 42 pts were included between September 2007 and January 2010 in 16 centers, with a mean age of 60.5 yrs (30-78), serum albumin 38.9 g/l (18-52), 59.5% with performance status 0. All courses of FOLFIRI, 90% RT and 75% of FU during CTRT, and surgery were performed in 39, 34 and 35 pts respectively. Complete treatment was performed in 31/42 pts (73.8%, 95% CI : 60.5-87.1), 28 pts had a R0 resection (80.0%), and 17 pts (40.5%) had at least one severe advserse event (grade 3-4). During FOLFIRI and CTRT, at least one severe adverse event (grade 3-4), was reported in 11 (26.2% , 95% CI: 13.9-42.0) and 8 pts (19.0% 95%CI: 8.6-34.1%) respectively. The post-operative death rate was 5.71%. Conclusions: The feasibility of the therapeutic sequence FOLFIRI–radiotherapy with 5FU-surgery is not significantly higher than 70%. According to the study design, this association would not be recommended.

ESD for Laterally Spreading Tumors in Colon: Experience for a Tertiary Unit

G A A b st ra ct s However the relations between chemoresistance, cytoskeleton and EMT are inevitable. In the present study, we investigated the effect of chemoresistance on cell motility, cytoskeleton, and EMT. METHODS: HT-29, a human colon cancer cell, was exposed to increasing doses of 5FU or oxaliplatin for 6 months to achieve resistance at clinically relevant doses. cDNA microarray analysis was performed for parent and resistant cells. Rates of proliferation and sensitivity to drugs were assessed using WST-1 Assay. Cell movement was analyzed by Timelapse imaging; the images were captured under an Axiovert 200M microscope (CarlZeiss) for eight hours at intervals of 15 min. For cytoskeleton study, morphologic and molecular changes investigated by immunofluorescence staining and PCR analyses. RESULTS; HT29 cells were finally resistant to 5FU (2μg/mL) and oxaliplatin (2μmol/L). cDNA microarray studies showed alteration of cytoskeletal gene expression (actin related genes including caldesmon were upregulated) and EMT-related genes (TGF-beta1, ZEB2, and Vimentin were upregulated and E-cadherin was downregulated) in both 5FU resistant cells and oxaliplatin resistant cells. The both resistant cells exhibited a decrease in cellular proliferation and EMTlike morphologic changes; spindle-cell shape, loss of polarity, intercellular separation, and pseudopodia formation. Time-lapse imaging showed random and accelerated cell motility. Immunofluorescence staining revealed that E-cadherin expression was decreased and caldesmon expression was enhanced. Caldesmon is reported to act as a potent repressor of cancer cell invasion, however in both resistant cells of this study, overexpressed caldesmon was not associated with F-actin and stress fiber was not developed, which was not typical EMT phenotype. Depletion of caldesmon with siRNA restored the chemoresistant cells to parental cell-like adherent epithelial shape. CONCLUSIONS: These results indicate that chemoresistant CRC developed altered cytoskeleton, accelerated cell motility and atypical EMT phenotype, and that caldesmon is involved in chemoresistance-related phenotypical changes, suggesting that the cytoskeleton related genes are potent molecular targets to chemoresistance and tumor invasion/metastasis.

Korneale Epitheliopathie nach Trabekulektomie mit postoperativer subkonjunktivaler 5-Fluorouracil-Injektion

The success of trabeculectomy in glaucoma not sufficiently controlled by maximal medical therapy substantially depends on postoperative scarring of the filtering bleb. This process of scarring can be inhibited by antimetabolites like mitomycin C (MMC) and 5-fluorouracil (5-FU). The aim of this study is the evaluation of incidence and long-term outcome of corneal surface defects and intraocular pressure following MMC- or 5FU-trabeculectomy using different doses of postoperative 5FU. A retrospective, non-randomised comparative study of 381 patients undergoing trabeculectomy with intraoperative application of either 5FU (group A, n = 169) or MMC (group B, n = 212) was performed. Based on the Wuerzburg bleb classification score (WBCS) for postoperative wound healing evaluation, 30 of these operations of group A (group B: n = 26) did not receive 5 FU postoperatively (controls), 67 (93) received up to 7 postoperative injections of 5 mg 5 FU (normal dosage group), and 72 (93) received more than 7 injections (high dosage group). Surface epithelial defects were routinely assessed by slit-lamp microscopy and fluorescein staining. Intraocular pressure (IOP) was measured by Goldmann applanation tonometry. In the normal dosage group the mean total dose of 5 FU was 25.8 ± 9.1 mg in group A (group B: 28.4 ± 7.5 mg) and in the high dosage group 54.2 ± 10.9 mg 5 FU (51.7 ± 11.8 mg), respectively. Increased doses of postoperative 5 FU induced more frequent corneal erosions in both groups. Corneal erosions were seen in controls in 16.7 % (26.9 %), in the normal dosage group in 55.2 % (47.3 %) and in the high dosage group in 77.8 % (59.1 %) in group A and group B, respectively. The incidence of a corneal erosion between group A and group B did not differ significantly (p = 0.074). The mean reduction of intraocular pressure in mmHg did not show a significant difference 12 months after trabeculectomy between controls and postoperative 5-FU operations. In eyes with beginning scarring of the filtering bleb after trabeculectomy the subconjunctival injection of 5-FU allows a similar reduction of intraocular pressure as in eyes without scarring. Corneal epitheliopathy following trabeculectomy and postoperative 5 FU is dose-dependent with higher doses leading to a higher incidence of corneal erosions. As serious corneal long-term complications are rare, risk-benefit analysis justifies the application of 5-FU after filtrating glaucoma surgery.

A phase II open-label prospective study of preoperative chemoradiation with oxaliplatin/5FU in locally advanced rectal cancer followed by total mesorectal excision and adjuvant FOLFOX6.

e14128 Background: 5FU based neoadjuvant chemoradiation (nCRT) is the standard of care for stage II/III rectal cancer. Pathologic complete response (pCR) and downstaging have been associated with improved outcomes. The addition of oxaliplatin (OXA) to neoadjuvant therapy may reduce distant disease recurrence. Adjuvant treatment with OXA for rectal cancer has been motivated by benefits demonstrated in stage III colon cancer. Objective: To determine the feasibility, toxicity, and efficacy of preoperative OXA/5FU and RT followed by total mesorectal excision (TME) and adjuvant FOLFOX6. Methods: 27 patients with stage II/III rectal cancer were treated with OXA 60 mg/m2 weekly continuous infusion 5FU of 225 mg/m2/d d1-5 with pelvic RT of 1.8 Gy/d for 28 doses. Adjuvant therapy consisted of 6 cycles of biweekly FOLFOX6. Results: 92% and 93% of intended neoadjuvant OXA and 5FU doses were given. First 5 patients enrolled received weekly continuous 5FU d1-7, later subjects received 5FU d1-5 due to toxicity. After nCRT, 10 subjects withdrew from study due to disease progression (n = 3), death (n = 1), and OXA intolerance (n = 6). 23 patients underwent TME, 20 pathologically downstaged and 13% attained pCR. 17 patients initiated adjuvant FOLFOX6 with 87% and 92% of intended doses of OXA and 5FU given. 1 patient withdrew from OXA intolerance and 1 death from cancer. Acute grade 3-4 toxicities occurred in 16 pts, mainly hypersensitivity reactions and OXA associated peripheral neuropathy. At a median follow up of 28 months, overall survival (OS) was 92% and disease-free survival (DFS) was 70%. Local recurrences occurred in the two patients with positive margins. Among 20 downstaged patients, 2 year OS/DFS were 100% and 85%, local and distant control were 95% and 90%. Patients who completed adjuvant FOLFOX had a 2 year OS of 100% and a DFS of 87.5%. Conclusions: The addition of OXA to nCRT and adjuvant therapy demonstrated encouraging downstaging rates and 2 yr OS/DFS in patients who completed therapy. Developing strategies to minimize prohibitive neuropathy and hypersensitivity reactions may allow a greater proportion of patients to benefit from this regimen. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration sanofi-aventis sanofi-aventis

Uridine triacetate for lethal 5-FU toxicity due to dihydropyrimidine dehydrogenase (DPD) deficiency.

e13505 Background: The enzyme dihydropyrimidine dehydrogenase (DPD) catalyzes the first step in degradation of 5-fluorouracil (5FU). Patients with complete or partial DPD deficiency (about 0.1% and 3% of the population, respectively) can experience severe or lethal toxicities after receiving standard doses of 5FU, and impaired clearance may underlie a large fraction of the ∼1,300 deaths per year due to 5FU toxicity in the US. Orally-administered uridine triacetate (vistonuridine) prevents or diminishes toxicities when administered after 5FU overexposure, and has been used successfully as an antidote in more than 28 patients to date who had received accidental overdoses of 5FU. Because DPD deficiency may alter 5FU clearance kinetics (versus 5FU overdoses in the setting of normal DPD activity), studies were conducted on reversal of 5FU toxicity in mice pretreated with the potent DPD inhibitor ethynyluracil (eniluracil; EU) to model DPD deficiency. Methods: Balb/C mice received 2 mg/kg EU i.p., followed by 1...

The effect of a novel small molecule inhibitor of FAK on viability of human colon cancer cells.

e13635 Background: Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that is overexpressed of a variety of human malignancies including colon cancer. As such, FAK represents a potential target for inhibiting colon cancer growth and progression. We have recently developed a novel small molecule inhibitor of FAK (1,2,4,5-Benzenetetraamine tetrahydrochloride; Y15) that blocks the Y397 autophosphorylation site of FAK, and we therefore hypothesized that Y15 would inhibit the viability of human colon cancer cells. Methods: Two related human colon cancer cell lines were utilized: SW480 (primary tumor) and SW620 (lymph node metastasis). Cells were screened for FAK production and Y397 autophosphorylation by Western blot analysis. An MTT assay was used to assess cell viability in the presence of different concentrations of Y15 alone (1, 10, 100 mcM), and 5-fluorouracil (5-FU; 1, 5, 25 mcM) alone or in combination with Y15 (1mcM). DMSO was used as a negative control and the FAK kinase inhibitor TAE226 used as a positive control. Results: FAK protein was detected in both cell lines, however the metastatic cells (SW620) expressed more FAK than did the primary tumor cells (SW480). In addition, the metastatic cells had greater amount of phosphorylated Y397 FAK. DMSO did not affect cell viability, while TAE226 did, as expected. Y15 inhibited viability in a dose dependent manner. 5FU did not affect viability at doses < 25 mcM. Interestingly, although 1mcM Y15 had no effect on viability, the addition of 1mcM Y15 to all doses of 5FU decreased viability dose dependently, thus sensitizing cells to 5FU. FAK expression and phosphorylation of Y397 were decreased by Y15 and mirrored the viability results. Conclusions: FAK protein is expressed in SW480 and SW620 colon cancer cells, but the metastatic SW620 cell express higher levels than their primary tumor counterparts. The novel small molecule inhibitor of FAK Y397 autophosphorylation (Y15) inhibits viability of both cell lines and does so in a dose dependent manner. In addition, Y15 increases cell sensitivity to 5FU. Taken together, these data suggest that Y15 may be a useful therapeutic agent for treating patients with colon cancer. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration CureFAKtor Pharmaceuticals

Comparison of two regimes of neoadjuvant chemoradiation in the treatment of rectal tumors: Bolus versus infusional fluorouracil.

e14130 Background: In metastatic rectal cancer, continuous infusion of fluorouracil (cFU) is more effective and less toxic than the bolus regimen. However, the ideal regimen of FU administration concomitant with radiotherapy (RDT) is not well established. There are few direct comparisons of cFU versus bolus FU in the neoadjuvant setting. Methods: We conducted a retrospective analysis of 78 patients with rectal cancer, treated from August/2002 to November/2008, with external beam pelvic radiation (50.4 Gy) concomitant with the following chemotherapeutic regimens: weekly bolus FU 350-425 mg/m2 or 350-380 mg/m2 D1-D5 in the 1º and 5° weeks (group I); or cFU 1 g/m2 D1-D5 during 1º and 5° week (group II). Relapse-free survival (RFS) was the primary endpoint. Pathological response rate was secondary endpoint. Results: Data from 78 patients were analyzed (I/II:55/23). Pretreatment characteristics were: 52% female; median age 55y/52y (I/II); clinical staging approach was: CT scan in 66/56% (I/II), and magnetic resonance in 34/52% (I/II). Clinical T3-T4 69/69% and cN+ 36/43% (I/II). Groups were well balanced. The median interval from RDT to surgery was 1.84 month. Sphincter-sparing surgery was performed in 75/86% (I/II).The proposed RDT was delivered in 94/100% (I/II) of patients and median total delivered FU dose was 2.1 g/10 g (I/II). Patients in group I also received leucovorin 20 mg/m2 in 90.4%. Pathologic T3-T4 was 36/31% (I/II) and pN+ 36/26% (I/II). Pathological complete response (pCR) was achieved in 28.3/9.1% (I/II). There was no significant association between pCR and regimen of treatment (p = 0.13). The median follow-up was 27.4 m, median RFS was not reached. In 2y, RFS was 73% in both groups (p = 0.59). Twenty-six patients relapsed, 1/15 (6%) (two patients were lost for follow up) among those with pCR and 25/56 (44%) (4 patients were lost for follow-up) among those with non-pCR. Conclusions: Pathologic complete response was associated with lower relapses rates in our series. There was no difference in pCR and RFS between bolus and infusional FU. Bolus FU remains a treatment option, associated with radiotherapy, in patients with locally advanced rectal carcinoma. No significant financial relationships to disclose.

Abstract 2621: Telomere length in peripheral blood mononuclear cells (PBMNC) predicts for leukopenia, neutropenia and mucositis in colorectal cancer patients treated with 5FU

Abstract Defining the parameters contributing to variability in clinical toxicity is necessary to optimise cancer treatment. Some variability is accounted for by variations in 5FU pharmacokinetics, differences in co-morbidity (liver &amp; renal), pre-disposing factors (gender &amp; age). But a considerable amount remains unexplained. This study aims to identify various factors contributing to such toxicity in colorectal cancer patients receiving 5FU. The variables chosen for study include those that control 5FU metabolism including measures of dihydropyrimidine dehydrogenase (DPD) activity which is critical for 5FU catabolism, together with polymorphic analysis of thymidylate synthase (TS), methyltetrahydrofolate reductase (MTHFR) and methionine synthase (MS) activity. The addition of pharmacodymamics and the ability of end-organs to respond to drug treatment further refined the predictive model, particularly the ability to identify those patients most likely to experience severe myelosuppression in response to chemotherapy. In this regard, the replicative capacity of bone marrow progenitors was determined by measuring telomere length (TL) in peripheral blood mononuclear cells (PBMNC). Clinical toxicity was determined in 42 colorectal patients receiving 5FU. Toxicity (≥ grade 2) included neutropenia (n=25), leukopenia (n=14), mucositis (n=19) and diarrhea (n=5). While the severity of toxicity significantly correlated with the magnitude of the insult, ie 5FU dose, the analysis also showed that toxicity significantly correlated with TL, with short telomeres predicting for higher toxicity. Univariate analysis showed TL significantly correlated with leukopenia (r=-0.461, P=0.009), neutropenia (r=-0.413, P=0.021) and mucositis (r=-0.341, P=0.048). Multivariate analysis further confirmed the significant role of TL in these clinical toxicities. Collectively, these results support the link between TL and progenitor replicative capacity. In conclusion, PBMNC TL may be exploited to tailor chemotherapy schedules for colorectal cancer patients receiving 5FU. 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 2621.

Hyperoxia increases the uptake of 5-fluorouracil in mammary tumors independently of changes in interstitial fluid pressure and tumor stroma

BackgroundHypoxia is associated with increased resistance to chemo- and radiation-therapy. Hyperoxic treatment (hyperbaric oxygen) has previously been shown to potentiate the effect of some forms of chemotherapy, and this has been ascribed to enhanced cytotoxicity or neovascularisation. The aim of this study was to elucidate whether hyperoxia also enhances any actual uptake of 5FU (5-fluorouracil) into the tumor tissue and if this can be explained by changes in the interstitium and extracellular matrix.MethodsOne group of tumor bearing rats was exposed to repeated hyperbaric oxygen (HBO) treatment (2 bar, pO2 = 2 bar, 4 exposures à 90 min), whereas one group was exposed to one single identical HBO treatment. Animals housed under normal atmosphere (1 bar, pO2 = 0.2 bar) served as controls. Three doses of 5FU were tested for dose response. Uptake of [3H]-5FU in the tumor was assessed, with special reference to factors that might have contributed, such as interstitial fluid pressure (Pif), collagen content, oxygen stress (measured as malondialdehyd levels), lymphatics and transcapillary transport in the tumors.ResultsThe uptake of the cytostatic agent increases immediately after a single HBO treatment (more than 50%), but not 24 hours after the last repeated HBO treatment. Thus, the uptake is most likely related to the transient increase in oxygenation in the tumor tissue. Factors like tumor Pif and collagen content, which decreased significantly in the tumor interstitium after repeated HBO treatment, was without effect on the drug uptake.ConclusionWe showed that hyperoxia increases the uptake of [3H]-5FU in DMBA-induced mammary tumors per se, independently of changes in Pif, oxygen stress, collagen fibril density, or transendothelial transport alone. The mechanism by which such an uptake occur is still not elucidated, but it is clearly stimulated by elevated pO2.

Colorectal cancer survival following adjuvant chemotherapy with weekly i.v. fluorouracil 425 mg/m2 and folinic acid 50mg

e15089 Background: Adjuvant chemotherapy for colorectal cancer (CRC) using fluorouracil (5FU) and folinic acid (FA) has been proven effective and the QUASAR trial showed that a weekly administration schedule was as effective as, and less toxic than, the same daily doses delivered over 5 days every 4 weeks (the “Mayo regimen”). However the 5FU dose used (370 mg/m2) was lower than in some trials and a higher 5FU dose was considered desirable if tolerated. We therefore implemented a weekly regimen using 5FU 425 mg/m2 and DL-folinic acid 50mg in 2001 and retrospectively evaluated its efficacy and tolerability. Methods: Patients with non-metastatic CRC at assessment by medical oncologists in this institution between 2001 and 2004 were included in the analysis. Data was gathered on patient characteristics, duration of adjuvant chemotherapy and survival. Actuarial survival was calculated using the Kaplan-Meier method. Results: 417 patients (pts) were seen: 181 females, 236 males; median age 67 yrs (24–89); 291 with colon cancer, 126 with rectal cancer; 1 stage 1; 100 stage 2, 316 stage 3. Median follow-up was 6.2 years. 210 pts with colon cancer received adjuvant weekly 5FU/FA (32 stage 2, 178 stage 3) as did 58 pts with rectal cancer (50 of whom also received concurrent chemoradiation). 75% of pts with colon cancer received all 30 planned doses and 59% of rectal cancer pts received all 20 planned doses. 3 year survival for all pts treated with this regimen was 83.0% and for the subgroups with colon and rectal cancer it was 82.4% and 84.5% respectively. For stage 2 and 3 colon cancer pts treated with this regimen 3 year survival was 87.9% and 76.0% respectively; for stage III rectal cancer pts it was 84.1%. Conclusions: These outcomes compare favorably on indirect comparison with results from the QUASAR trial (which reported 3 year survival of 70.6%) and suggest that using a higher 5FU dose in this regimen is tolerable and may be advantageous. No significant financial relationships to disclose.

Topoisomerase I involvement in schedule-dependent interaction between 5-fluoro-uracil and irinotecan in the treatment of colorectal cancer

5-Fluoro-uracil (5FU), an antimetabolite drug, stimulates expression of topoisomerase I (tpI) in adenocarcinoma cancer cells. When 5FU is given in combination with Irinotecan (IR), a tpI poison, the most effective regimen is represented by IR given before low doses of 5FU. Hence, despite their distinct mechanisms of action, the molecular basis for successful combination and schedule of 5FU and IR in the treatment of colorectal cancer rests on the opposing drug effects on the expression and poisoning of the tpI enzyme.

Chemoresistant Colorectal Cancer Cells, the Cancer Stem Cell Phenotype, and Increased Sensitivity to Insulin-like Growth Factor-I Receptor Inhibition

5-Fluorouracil (5FU) and oxaliplatin are standard therapy for metastatic colorectal cancer (CRC), but the development of chemoresistance is inevitable. Because cancer stem cells (CSC) are hypothesized to be chemoresistant, we investigated CSC properties in newly developed chemoresistant CRC cell lines and sought to identify targets for therapy. The human CRC cell line HT29 was exposed to increasing doses of 5FU (HT29/5FU-R) or oxaliplatin (HT29/OxR) to achieve resistance at clinically relevant doses. Western blotting and flow cytometry were done to determine molecular alterations. The insulin-like growth factor-I receptor (IGF-IR) monoclonal antibody (mAb) AVE-1642 was used to inhibit signaling in vitro and in vivo using murine xenograft models. HT29/5FU-R and HT29/OxR showed 16- to 30-fold enrichment of CD133(+) cells and 2-fold enrichment of CD44(+) cells (putative CRC CSC markers). Resistant cells were enriched 5- to 22-fold for double-positive (CD133(+)/CD44(+)) cells. Consistent with the CSC phenotype, resistant cells exhibited a decrease in cellular proliferation in vitro (47-59%; P < 0.05). Phosphorylated and total IGF-IR levels were increased in resistant cell lines. HT29/5FU-R and HT29/OxR cells were approximately 5-fold more responsive to IGF-IR inhibition relative to parental cells (P < 0.01) in vitro. Tumors derived from HT29/OxR cells showed significantly greater growth inhibition in response to an IGF-IR mAb than did parental cells (P < 0.05). Chemoresistant CRC cells are enriched for CSC markers and the CSC phenotype. Chemotherapy-induced IGF-IR activation provided for enhanced sensitivity to IGF-IR-targeted therapy. Identification of CSC targets presents a novel therapeutic approach in this disease.

The Sympathetic Nervous System Regulates Hematopoietic Stem and Progenitor Cell Homing and Engraftment.

The sympathetic nervous system (SNS) controls hematopoietic stem and progenitor cell (HSPC) release from their niches in the bone marrow (BM) by acting on specific niche cells: bone-lining osteoblasts during mobilization (Cell 2006; 124:407) and CXCL12-secreting BM stromal cells (Nature 2008; 452:442) in homeostasis. However, it remains unknown whether the SNS controls other processes in HSC physiology. Here, we show that an intact SNS is necessary for bone marrow reconstitution. Transplantation of lethally-irradiated recipient mice, in which the SNS was lesioned using 6-hydroxydopamine (6OHDA), with 105 healthy BM nucleated cells resulted in 65% survival of the sympathectomized mice compared to 100% survival in the control groups (6OHDA, not irradiated; Saline, not irradiated; Saline, irradiated and transplanted; p<0.01, Kaplan-Meyer survival and Logrank test). Peripheral blood analyses revealed hematopoietic failure and a severe reduction in trilineage cell counts during the recovery phase. These results indicated that HSPCs engrafted with diminished efficiency in sympathectomized mice. Since donor HSPCs were obtained from intact wild-type mice the observed phenotype suggested that the SNS regulated HSPC engraftment by acting on niche cells. The observed phenotype could be due to reduced homing (i.e. the ability of HSPCs to migrate and enter the bone marrow) or to reduced proliferation of HSPC after appropriate homing. To evaluate these two possibilities, we first injected HSPCs into lethally irradiated 6OHDA-treated or control recipients and allowed the cells to migrate to the BM for 3 hours (homing assays). We found that 2.7-fold fewer donor clonogenic progenitors (CFU-C) could be detected in the BM of sympathectomized mice compared to control animals (p<0.001), indicating that an intact SNS is required for HSPC homing to the bone marrow. To determine whether SNS signals are required for HSPC proliferation after homing, we evaluated the proliferative capacity of HSPCs following the administration of the cytotoxic drug 5-fluorouracyl (5FU). Mice treated with 6OHDA or control recipient mice received a single dose of 5FU (150 mg/kg) and their hematopoietic parameters and survival were monitored for 16 days. Peripheral blood analysis revealed reductions in both WBC (1.6 fold; p<0.05) and RBC (1.4 fold; p<0.01) in 6OHDA-treated compared to SNS-intact mice. Further analyses revealed a strong reduction (1.8 fold; p<0.01) in the BM cellular content suggesting that HSPC failed to proliferate normally in 6OHDA-treated mice. The number of CFU-C and stem cell-enriched Lin−Sca1+c-kit+ (LSK) cells in the recovery phase (12 days after 5FU) were reduced 1.9-fold (p<0.01). Moreover, 5FU produced a high mortality rate in the 6OHDA-lesioned group (76% survival at the end of the study; p<0.05 Kaplan- Meyer survival and Logrank test) when compared to 5FU-treated SNS-intact mice (100% survival). These results suggest that HSPC require SNS signals to proliferate in response to stress to restore a functional hematopoiesis. Taken together these data indicate that the sympathetic nervous system acts on the hematopoietic stem cell niche to control both homing and proliferation in the bone marrow, two critical steps that determine the success of a bone marrow transplantation procedure.

Selective Protection by Uridine of Growth Inhibition by 5-Fluorouracil (5FU) Mediated by 5FU Incorporation into RNA, But Not the Thymidylate Synthase Mediated Growth Inhibition by 5FU-Leucovorin

Fluorouracil (5FU) acts by RNA-incorporation and inhibition of thymidylate synthase; the first action is counteracted by uridine, and the second is enhanced by leucovorin (LV). Growth inhibition of C26-10 colon cancer cells by 5FU was enhanced by LV and rescued by uridine, but 5FU-LV was only partially rescued by uridine. In WiDr cells, 5FU sensitivity was not enhanced by LV, while both 5FU and 5FU-LV were rescued by uridine. Intermediate trends were found in SW948 and HT29 cells. Uridine rescue in mice allowed 1.5-fold increase in 5FU dose, leading to 2-fold increase in the antitumor effect and thymidylate synthase inhibition in resistant Colon-26 tumors. In the sensitive Colon-26-10 tumor, uridine rescue decreased 5FU-RNA incorporation > 10-fold, without affecting the antitumor activity. The use of LV and uridine can differentiate between two mechanisms of action of 5FU.

Pharmacokinetics of 5-Fluorouracil in Patients Heterozygous for the IVS14+1G > A Mutation in the Dihydropyrimidine Dehydrogenase Gene

5-Fluorouracil (5FU) and capecitabine are two of the most frequently prescribed chemotherapeutic drugs for the treatment of patients with cancer. Administration of test doses of 5FU to eight patients heterozygous for the IVS14+1G > A mutation and five control patients showed that the AUC and clearance were weak parameters with respect to the identification of patients with a DPD deficiency. However, highly significant differences were observed for the terminal half life of 5FU between DPD patients and controls. Thus, a DPD deficiency could be predicted from 5FU blood concentrations measured after the administration of a test dose of 5FU.

A phase II study of an adapted CT with oxaliplatin (Oxa) and bolus 5FU in I-line treatment of metastatic CRC in elderly patients not eligible to FOLFOX

15124 Background: FOLFOX and FOLFIRI have been established to be an effective I-line CT for mCRC. Not all over 70-yrs old pts can receive infusional 5-FU because of cardiac comorbidity, refuse of infusional CT or vulnerability state at the comprehensive geriatric assessment (CGA). Till now no alternative schedules containing Oxa have been assessed in elderly pts. The aim of the present study was to evaluate the feasibility and activity of biweekly Oxa plus bolus 5FU and low dose LV as I-line CT. Methods: pts ≥70 yrs with measurable, chemonaive mCRC, ECOG PS ≤2, not eligible to infusional 5FU, fit or vulnerable at CGA (Balducci et al) received Oxa 85 mg/m2 on d 1 and 15, LV 20 mg/m2 plus bolus 5FU 500 mg/m2 on d 1, 8 and 15 every 28d. Study design was 1 stage, estimated sample size 34. Toxicity was the primary endpoint. Response was evaluated by CT-scan every 2 cy. Results: 35 pts, median age 74 (range 70–84) entered the study. Ten pts (28.6%) had cardiological comorbidities. Median number of comorbidities was 1.3 among 20 vulnerable pts, 0 among 15 fit pts. Toxicity according to CTC v 3.0 (see table), was not related to age or CGA. 46.7% of fit pts and 70% of vulnerable pts received < 6 cycles of CT because of toxicity (7 pts), PD (6 pts) or refuse (8 pts). Out of 28 valuable pts 10 PR were observed for an RR of 35.7% (95% CI 17.9–53.4%). Eleven pts had SD (39.3%) while 7 progressed during treatment (25%). After a median follow up of 29.3 mo 32 pts progressed or died, with a median PFS of 9.4 mo. Totally 24 out of 35 pts died, for a median OS of 16.3 mo. A clinical difference in terms of OS among 15 pts receiving II line CT and the other 20 receiving only best supportive care (13.9 vs 11.4, p=0.19 n.s.) was reported. Conclusions: Biweekly Oxa with bolus 5-FU is a safe and effective alternative in elderly pts not susceptible to FOLFOX because of refuse by pts or vulnerability at CGA. Toxicity Toxicities Grade 2 Grade 3 Grade 4 Number % Number % Number % Anemia 4 11.4 1 2.8 0 0 Neutropenia 3 8.6 3 8.6 1 2.8 Trombocytopenia 3 8.6 0 0 0 0 Diarrhea 2 5.7 5 14.3 1 2.8 Mucositis 2 5.7 0 0 1 2.8 Vomiting 2 5.7 1 2.8 0 0 Neurotoxicity 6 17.1 3 8.6 1 2.8 Fatigue 3 8.6 1 2.8 0 0 No significant financial relationships to disclose.

Are we use of chemotherapy for elderly stage III colon cancer patients? An analysis from the Cancer Care Outcomes & Research Surveillance Consortium (CanCORS)

6500 Background: Multiple studies have documented lower rates of use of adjuvant therapy for colorectal cancer with increasing patient age despite evidence from RCTs that older patients (pts) experience similar benefits from treatment. This suggests the concern that pts treated on those trials may not be representative of the typical elderly colorectal cancer patient. We therefore examined the outcomes of adjuvant therapy for colorectal cancer in a nationally representative sample of pts treated in the routine care setting. Methods: As part of the CanCORS observational cohort study, we assessed important clinical morbid events (CME) recorded in the medical records (e.g., sepsis, myocardial infarction) for a population-based sample of 705 patients with incident colon cancer from multiple U.S. regions. We used Poisson models with propensity score to calculate adjusted mean number of CME events summed, from colectomy to 15 months post- diagnosis, by age. We adjusted for demographics, site, survey type, comorbidity, pre-dx health status, clinical complications during the pre- and post-op periods prior to chemo use; and then for 1st 5FU dose and route, chemo dose reduction, and chemo duration. Results: Overall, of 705 stage III pts, the prevalence of CME was none for 67%, one for 22%, and ≥two for 11% with a mean of 0.49 (SD 0.91) CME following surgery to the end of study. The adjusted mean number of CME are not worse for older pts, even after adjustment for 1st chemo dose and route, dose reduction and chemo duration. Conclusions: Although elderly patients are much less likely than younger patients to receive adjuvant chemotherapy for stage III colon cancer, those who receive chemotherapy, experience similar rates of clinical morbid events. Age Categories (years) Adjusted Mean Number of Clinical Morbid Events (n=705) Pts Receiving Chemo (N=517) No Chemo (n=188) Without adjustment for chemo dose After adjustment for chemo dose 21–55 (n=79) 0.71 (n=8) 0.46 0.45 56–65 (n=153) 0.40 (n=19) 0.54 0.53 66–75 (n=180) 0.48 (n=38) 0.49 0.51 >75 (n=293) 0.38 (n=123) 0.47 0.48 Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration National Cancer Institute