Rescuing effect of folates on methotrexate cytotoxicity in human trophoblast cells.

OBJECTIVES: Methotrexate (MTX)is a folate antagonist that is administered in several conditions such as rheumatoid arthritis. Its use may associate with adverse effects presumably originating from folate deficiency. Although MTX side effects could be decreased by folate supplementation, the current guideline on folate administration is not precisely established, which could result in irreversible damage especially in high-risk groups like women in childbearing-age. Thus, this study aimed to investigate the in vitro rescuing effect of different folates including folic acid (FA), 5-methyltetrahydrofolate (MTHF) and folinic acid (5-Formyltetrahydrofolic acid, FTHF) on MTX-treated trophoblast cells. METHODS: HTR-8/SVneo cells were stressed with a minimum effective dose of MTX and simultaneously treated with different concentrations of FA, MTHF or FTHF. The rescuing effect was assessed by MTT viability assay. The evaluation was completed by microscopic monitoring, apoptosis assessment and measuring LINE-1 DNA methylation. RESULTS: The MTT viability assay showed no MTX-rescuing effect of FA, but a significant effect of FTHF or MTHF. Microscopic observations supported the results of the viability assay. Accordingly, apoptosis was reduced in MTHF or FTHF treatments, while FA has no effect on the apoptosis induced by MTX. The LINE-1 methylation was not affected by MTX treatment, and not significantly modified in folate supplemented cultures. CONCLUSIONS: Despite the general acceptance of administering FA to prevent adverse events of MTX therapy, our findings suggest that FA may not be optimal, and indicate FTHF or MTHF as a better choice. This study on trophoblast cells suggests that FTHF may be the optimal folate, particularly for women in childbearing-age.

Pathogenesis of FOLFOX induced sinusoidal obstruction syndrome in a murine chemotherapy model.

BACKGROUND & AIMS: Sinusoidal obstruction syndrome (SOS) following oxaliplatin based chemotherapy can have a significant impact on post-operative outcome following resection of colorectal liver metastases. To date no relevant experimental models of oxaliplatin induced SOS have been described. The aim of this project was to establish a rodent model which could be utilised to investigate mechanisms underlying SOS to aid the development of therapeutic strategies. METHODS: C57Bl/6 mice, maintained on a purified diet, were treated with intra-peritoneal FOLFOX (n=10), or vehicle (n=10), weekly for five weeks and culled one week following final treatment. Sections of the liver and spleen were fixed in formalin and paraffin embedded for histological analysis. The role of oxidative stress on experimental-induced SOS was determined by dietary supplementation with butylated hydroxyanisole and N-acetylcysteine. RESULTS: FOLFOX treatment was associated with the development of sinusoidal dilatation and hepatocyte atrophy on H&E stained sections of the liver in keeping with SOS. Immunohistochemistry for p21 demonstrated the presence of replicative senescence within the sinusoidal endothelium. FOLFOX induced endothelial damage leads to a pro-thrombotic state within the liver associated with upregulation of PAI-1 (p<0.001), vWF (p<0.01) and Factor X (p<0.001), which may contribute to the propagation of liver injury. Dietary supplementation with the antioxidant BHA prevented the development of significant SOS. CONCLUSIONS: We have developed the first reproducible model of chemotherapy induced SOS that reflects the pathogenesis of this disease in patients. It appears that the use of antioxidants alongside oxaliplatin based chemotherapy may be of value in preventing the development of SOS in patients with colorectal liver metastases.

Refining the UGT1A haplotype associated with irinotecan-induced hematological toxicity in metastatic colorectal cancer patients treated with 5-fluorouracil/irinotecan-based regimens.

Despite the importance of UDP-glucuronosyltransferase (UGT) 1A1*28 in irinotecan pharmacogenetics, our capability to predict drug-induced severe toxicity remains limited. We aimed at identifying novel genetic markers that would improve prediction of irinotecan toxicity and response in advanced colorectal cancer patients treated with folic acid (leucovorin), fluorouracil (5-FU), and irinotecan (camptosar)-based regimens. The relationships between UGT1A candidate markers across the gene (n = 21) and toxicity were prospectively evaluated in 167 patients. We included variants in the 3'untranscribed region (3'UTR) of the UGT1A locus, not studied in this context yet. These genetic markers were further investigated in 250 Italian FOLFIRI-treated patients. Several functional UGT1A variants, including UGT1A1*28, significantly influenced risk of severe hematologic toxicity. As previously reported in the Italian cohort, a 5-marker risk haplotype [haplotype II (HII); UGTs 1A9/1A7/1A1] was associated with severe neutropenia in our cohort [odds ratio (OR) = 2.43; P = 0.004]. The inclusion of a 3'UTR single-nucleotide polymorphism (SNP) permitted refinement of the previously defined HI, in which HIa was associated with the absence of severe neutropenia in combined cohorts (OR = 0.55; P = 0.038). Among all tested UGT1A variations and upon multivariate analyses, no UGT1A1 SNPs remained significant, whereas three SNPs located in the central region of UGT1A were linked to neutropenia grade 3-4. Haplotype analyses of these markers with the 3'UTR SNP allowed the identification of a protective HI (OR = 0.50; P = 0.048) and two risk haplotypes, HII and HIII, characterized by 2 and 3 unfavorable alleles, respectively, revealing a dosage effect (ORs of 2.15 and 5.28; P ≤ 0.030). Our results suggest that specific SNPs in UGT1A, other than UGT1A1*28, may influence irinotecan toxicity and should be considered to refine pharmacogenetic testing.

An experimental study to identify the potential role of pharmacogenomics in determining the occurrence of oxaliplatin-induced liver injury.

BACKGROUND: Oxaliplatin-based chemotherapy has been linked to the development of sinusoidal obstruction syndrome (SOS), which is detrimental to outcome after liver resection for colorectal liver metastases (CLM). The aim of this study was to determine how the expression of genes involved in the transport and metabolism of FOLFOX chemotherapy impacts on tissue injury in a murine model of CLM. METHODS: Experimental CLM was established in C57/B16 mice and treated with FOLFOX chemotherapy. After 3 weeks, the animals were killed and RNA extracted from liver, spleen and tumour tissue. DNA damage was assessed by immunohistochemistry for γH2AX. Gene expression was determined by reverse transcriptase polymerase chain reaction. RESULTS: FOLFOX treatment was associated with an increase in the number of γH2AX-positive cells in both the spleen (P < 0.01) and tumour tissue (P < 0.01), but not the liver. Tissue resistance to injury following FOLFOX was associated with high expression of the copper transporter ATP7B. Differences in the expression of genes related to 5-fluorouracil metabolism or DNA repair did not correlate with the severity of tissue injury. CONCLUSIONS: High levels of expression of ATP7B are associated with resistance to tissue injury following FOLFOX chemotherapy. Polymorphisms in the ATP7B gene may explain varying susceptibility to SOS among patients following oxaliplatin-based chemotherapy.

Effectiveness and safe use of modified FOLFOX-6 for metastatic gastric cancer with signet ring cell components complicated by disseminated intravascular coagulation and diffuse bone marrow carcinomatosis.

We report the case of a 62-year-old woman with a metastatic gastric cancer complicated by diffuse bone marrow carcinomatosis, disseminated intravascular coagulation (DIC) and microangiopathic hemolytic anemia (MHA) treated by modified FOLFOX-6 as front-line chemotherapy regimen. This chemotherapy showed clinical, morphological and biological efficiency and safety in this rare and severe hematological complication at initial diagnosis. Furthermore, this is the first case of diffuse bone carcinomatosis from a gastric cancer to be monitored by positron emission tomography integrated computed tomography (PET-CT) scan using 18-fluorodeoxyglucose (18-FDG).

Efficacy and safety of irinotecan-based chemotherapy for advanced colorectal cancer outside clinical trials: an observational study.

BACKGROUND: This prospective observational study in typical community-based outpatient clinics evaluated the efficacy and toxicity of weekly and biweekly irinotecan-based chemotherapies and their compatibility depending on age. METHODS: 601 patients with advanced or metastatic colorectal cancer receiving first-, second-, or third-line irinotecan-based therapy were regularly analyzed for response and toxicity until the end of therapy. RESULTS: The median age was 65 (28-87) years, approximately one-third of the patients were ≥70 years old. Of all patients, 405 were treated weekly and 68 biweekly. Median overall survival (OS) for first-line therapy was 26.5 months for the <70-year-old patients and 19.4 months for the ≥70-year-old patients. Toxicities were moderate in all groups. Tumor growth control rates (TCR) and median time to progression (TTP) were marginally better for patients <70 years old. Median TTP was 9.9 months in first-line therapy, 9.8 months after adjuvant therapy, 7.7 months in second-line, and 6.4 months in third-line therapy. CONCLUSIONS: Toxicity and response data from this observational study clearly confirm the positive results from previous clinical studies and show a slight ad-vantage in efficacy for the <70-year-old patients.

Using zebrafish to assess the effect of chronic, early developmental exposure to environmentally relevant concentrations of 5-fluorouracil and leucovorin.

Environmental contaminants can deleteriously affect aquatic animals. One such contaminant is 5-fluorouracil (5-FU), a long-prescribed chemotherapeutic drug. Leucovorin (LV) is co-administered with 5-FU, potentiating its effects. Zebrafish (Danio rerio) larvae were reared in ng/L treatments of either 5-FU, LV, or a combined 5-FU/LV mixture for 8 dy. Survival was measured daily and swimming behavior assessed every other day. After 8 dy, larval length was measured, and densitometry of p53-labeled cryostat sections determined the extent of apoptosis. No significant differences in survival or apoptosis were found; larvae in the highest concentrations were largest. Changes in behavior of 5-FU-treated larvae were based on exposure duration; changes in LV-treated larvae were affected by drug concentration and duration. Larvae co-exposed to 5-FU/LV had responses like 5-FU-treated larvae. Overall, early developmental exposure of zebrafish larvae to environmentally-relevant concentrations of 5-FU and LV did not adversely affect survival, growth, and behavior suggesting realistic concentrations are sublethal and non-toxic.

FOLFIRI-Mediated Toxicity in Human Aortic Smooth Muscle Cells and Possible Amelioration with Curcumin and Quercetin.

Systemic chemotherapy-mediated cell toxicity is a major risk factor for cardiovascular disease and atherosclerosis. Life-threatening acute events of the FOLFIRI (irinotecan, folinic acid and 5-fluorouracil) regimen are mainly due to DNA damage induced by antimetabolite and topoisomerase inhibition effects. However, the role of human aortic smooth muscle cells (HaVSMCs) in this process and the mechanisms of oxidative stress, DNA and protein damage and apoptosis have not been investigated. Therefore, the effects of curcumin and quercetin on HaVSMC survival in the generation of molecular and cellular toxicity by FOLFIRI treatment and the involvement of vital cellular signalling pathways were investigated. We analysed both FOLFIRI toxicity and the therapeutic potential of quercetin and curcumin in terms of HaVSMC damage using molecular probe and florescence staining, Random Amplified Polymorphic DNA (RAPD), qRT-PCR and Western blot assays. Our study presents two preliminary findings: (a) in HaVSMCs, FOLFIRI treatment significantly induces oxidative damage to both DNA and protein, leading to a dramatic increase in caspase-dependent apoptotic death through P53-mediated Caspase3-dependent mitochondrial apoptosis, and results in TNF-α/Caspase8-mediated necrotic death, and (b) flavonoids not only regulate the expression of genes encoding antioxidant enzymes and increase DNA damage but also limit programmed and necrotic cell death processes in HaVSMCs. Our results clearly indicate the potential for curcumin and, particularly, quercetin as preventative chemotherapeutic interventions for cardiovascular toxicity induced by the FOLFIRI regime in HaVSMCs.

Development and assessment of novel all-in-one parenteral formulations with integrated anticoagulant properties for the concomitant delivery of 5-fluorouracil and calcium folinate.

5-Fluorouracil in combination with its biomodulator folinic acid maintains a pivotal position in current anticancer treatment regimens. However, limitations in clinical management persist with the administration of these drugs. These limitations are associated with the use of a high pH to maintain 5-fluorouracil in solution, resulting in high rates of phlebitis and catheter blockages. Herein, we describe and compare initial studies on novel all-in-one formulations of 5-fluorouracil and folinic acid incorporating either sulfated or hydroxypropyl beta-cyclodextrins at physiological pH that potentially address these issues. All formulations markedly improved the stability of supersaturated solutions of 5-fluorouracil in the presence of folinic acid. In-vitro evaluation of the PC-3, HCT-116, MDA-MB-231, PC-14, and COLO-201 human carcinoma cell lines showed that all formulations exhibited equivalent or better cytotoxicity compared with cells exposed to 5-fluorouracil and folinic acid. Thus, these cyclodextrins do not compromise the cytotoxicity of 5-fluorouracil. Preliminary in-vivo dose tolerance profiles of the formulations were also equivalent to 5-fluorouracil and folinic acid administered separately. Furthermore, given the association between thrombosis and cancer, the potentially beneficial anticoagulant activity of the sulfated cyclodextrin-based formulations was also confirmed in vitro. Extended activated partial thromboplastin times and prothrombin times were observed for the sulfated cyclodextrins in human plasma both as individual compounds and as components of the formulations. In conclusion, these novel all-in-one formulations maintain the in-vitro potency while overcoming the accepted incompatibility of 5-fluorouracil and folinic acid, and represent improved injectable forms of 5-fluorouracil that may reduce phlebitis, catheter blockages, and thromboembolic events.

[Reduction of oxaliplatin-related neurotoxicity by Gosha-jinki-gan].

PURPOSE: Oxaliplatin in combination with infusional 5-fluorouracil/Leucovorin (FOLFOX) has emerged as the treatment of choice for advanced-stage colorectal cancer. Sensory neurotoxicity is its dose-limiting toxicity. We decided to use Gosha-jinki-gan for prevention of oxaliplatin-related neurotoxicity following the report of Fushiki et al. METHODS: The subjects were 14 patients with metastatic colorectal cancer. Oxaliplatin (85 mg/m(2)) was given intravenously as a FOLFOX4 regimen. All 14 patients received Gosha-jinki-gan every day after first oxaliplatin infusion. RESULT: 7 patients had grade 3 toxicity(neutropenia 6, thrombocytopenia 1). Sensory neuropathy occurred in 10 patients (71.4%). There was no neurotoxicity with functional impairment in this study. CONCLUSIONS: Gosha-jinki-gan seems to prevent acute oxaliplatin-induced neurotoxicity.

[Systemic treatment of peritoneal metastases]. / Systemische Behandlungsmöglichkeiten der Peritonealkarzinose.

Peritoneal metastases are common in metastatic disease of many tumour types and thus are determinant for prognosis and development of tumour-related symptoms that jeopardise quality of life. Systemic chemotherapy has proven efficacious in improving both prognosis and quality of life in numerous tumour types and should therefore be considered as part of the treatment strategy--although there is no large body of data from predefined cohorts with"only peritoneal" manifestation. In further clinical trials therefore, improvement of systemic chemotherapy by integration of novel agents should be implemented in multimodal treatment approaches combining systemic treatment, cytoreductive surgery, and intraperitoneal treatment strategies.

Pharmacology and phase I trial of high-dose oral leucovorin plus 5-fluorouracil in children with refractory cancer: a report from the Children's Cancer Study Group.

Because of the synergy seen in adult trials when 5-fluorouracil is combined with leucovorin, we initiated a Phase I trial of this combination in children's refractory cancer. Leucovorin, an equal mixture of the (6R,S)-diastereoisomers, was administered p.o. for 6 consecutive days as 4 equal doses at 0, 1, 2, and 3 h totaling 500 mg/m2/day. 5-Fluorouracil was given daily on days 2 to 6 as an i.v. bolus immediately following the last dose of leucovorin. The leucovorin dose was held constant while the 5-fluorouracil dose was escalated in cohorts of patients from 300 mg/m2/day to its maximally tolerated dose. Thirty-five patients (19 with acute leukemia and 16 with solid tumors) were evaluable for toxicity. The maximally tolerated dose of FUra was 450 mg/m2/day for 5 treatments for patients with solid tumors and 650 mg/m2/day for 5 treatments for the children with leukemia. The dose-limiting toxicities were myelosuppression and stomatitis. Other side effects included transient, mild elevations of serum transaminases, mild nausea, vomiting, and diarrhea. The pharmacokinetics of high-dose p.o. leucovorin was studied in 23 children. There was considerable interpatient variability in the plasma concentrations of total bioactive folates (TBAF), (6S)-leucovorin, and (6S)-5-methyltetrahydrofolic acid. The maximum plasma concentration (Cmax) of TBAF was 821 +/- 97 (SE) nM, occurring at a median of 8 h; the Cmax of (6S)-leucovorin was 77 +/- 11 nM, occurring at 4 h. The TBAF concentration fell to 146 +/- 42 nM by 24 h. (6S)-5-Methyltetrahydrofolic acid accounted for 90 +/- 7% of the TBAF at the Cmax. The plasma concentration of (6R)-leucovorin, the unnatural isomer, was equal to that of TBAF. Thus, p.o. leucovorin reduced the 5-fold excess of (6R)-leucovorin over TBAF seen after i.v. doses. The relative amounts of the three major plasma species were approximately the same as in adults, even though the Cmax of each compound was lower.

5-Fluorouracil and folinic acid in the treatment of metastatic colorectal cancer: a randomized comparison. A Southwest Oncology Group Study.

In order to determine the clinical applicability of the in vitro observation of enhanced cytotoxicity of 5-fluorouracil (5-FU) in the presence of excess reduced folates, the Southwest Oncology Group (SWOG) performed a randomized trial evaluating two dose schedules of 5-FU and folinic acid (FA) in 128 patients with metastatic colorectal cancer. Of 125 eligible patients, 62 were randomized to receive bolus FA (200 mg/m2 days 1 through 4) in addition to 5-FU (1,000 mg/m2 days 1 through 4) by continuous four-day infusion (infusion arm), while 63 were randomized to receive bolus FA (200 mg/m2 days 1 through 5) in addition to 5-FU (325 mg/m2 days 1 through 5) by bolus injection (bolus arm). The toxicities of the two schedules differed, with stomatitis being more severe in the infusion arm and leukopenia being more severe in the bolus arm. The response rates and survival data for the two arms are nearly identical. The median survival of patients on the infusion arm is 11.0 months and of patients on the bolus arm, 10.3 months. The infusion arm produced one complete response (CR) and 12 partial responses (PRs), for a major response rate of 21% of eligible patients. The bolus arm produced three CRs and 11 PRs, for a major response rate of 22% of eligible patients. The response rate produced is minimally superior to recent cooperative group studies of colorectal cancer, but the response rate and survival experience are within the range of experience for treatment with 5-FU alone.

Phase II trial of chronomodulated infusion of high-dose fluorouracil and l-folinic acid in previously untreated patients with metastatic colorectal cancer.

PURPOSE: To study tolerability and efficacy of an intensified chronomodulated schedule of fluorouracil (5-FU) and l-folinic acid (l-FA) as first-line treatment of metastatic colorectal cancer, 5-FU was given near individually determined dose-limiting toxicity in a multicenter phase II trial. PATIENTS AND METHODS: One hundred patients (68 men and 32 women, median age 62 years, World Health Organization performance status less-than-or-equal 2) with previously untreated and inoperable metastases received chronomodulated daily infusion of 5-FU/l-FA (from 10:00 PM to 10:00 AM with peak at 4:00 AM). 5-FU dose was escalated from 900 to 1,100 mg/m(2)/d with fixed dose of l-FA at 150 mg/m(2)/d for 4 days every 14 days. RESULTS: 5-FU dose escalation was achieved in 66% of the patients. Grade 3 to 4 toxicities mainly consisted of nausea or vomiting (14% of patients and 1.5% of courses), hand-foot syndrome (38% of patients and 8% of courses), mucositis (26% of patients and 4% of courses), and diarrhea (21% of patients and 2.3% of courses). Objective response rate (ORR) was 41% (95% confidence interval, 31.5% to 50.5%). Twenty patients underwent metastases surgery; among these, 12 had a complete resection. Median progression-free survival was 7 months. Median survival was 17 months; 28% of the patients were alive at 2 years and 18.6% at 3 years. CONCLUSION: The ORR achieved with intensified chronomodulated delivery of 5-FU/l-FA was nearly twice as high as that earlier obtained by our cooperative group using less intensive 5-FU/FA chronotherapy.

Ratio of 2'-deoxyadenosine-5'-triphosphate/thymidine-5'-triphosphate influences the commitment of human colon carcinoma cells to thymineless death.

In colon cancers induction of a thymineless state following inhibition of thymidylate synthase (TS) by 5-fluorouracil combined with leucovorin can initiate a cytotoxic response. Using a 5-fluorouracil-leucovorin-treated human colon carcinoma cell line (GC3/cl) and a clonally derived TS- mutant, initiation events that dictate the onset of and commitment to thymineless death have been examined. Initial events related to a temporally associated decrease in dTTP and elevation in the dATP pools; no depletion of dGTP or elevation in dCTP was detected. Nucleosomal degradation of DNA commenced at 24 h in TS- and 49 h in GC3/c1, and was associated with the more rapid development of an imbalance in the dATP and dTTP pools and a higher dATP:dTTP ratio in TS- cells. The contribution of elevated dATP or depleted dTTP pools to thymineless death was subsequently determined by treatment of GC3/cl or TS- cells with deoxyadenosine to elevate the dATP pool either under thymidine-replete or thymineless conditions. Thus, deoxyadenosine supplementation under dTTP-replete conditions elevated the dATP pool for 16 h and was cytotoxic to cells. During dTTP depletion elevated dATP was maintained, and cytotoxicity was significantly and rapidly enhanced by deoxyadenosine but could be reversed by thymidine. Data suggest that maintenance of elevated dATP and the dATP:dTTP ratio are essential initiation events in the commitment of colon carcinoma cells to thymineless death.

Modulation of the Fas signaling pathway by IFN-gamma in therapy of colon cancer: phase I trial and correlative studies of IFN-gamma, 5-fluorouracil, and leucovorin.

Potentiation of 5-fluorouracil/leucovorin (FUra/LV) cytotoxicity by IFN-gamma in colon carcinoma cells is dependent on FUra-induced DNA damage, the Fas death receptor, and independent of p53 and RNA-mediated FUra toxicity, which occurs in normal gastrointestinal tissues. This provides a rationale for enhancing the selective action of FUra/LV by IFN-gamma in the treatment of colorectal carcinoma. Based on results from our preclinical studies we designed a Phase I trial combining FUra (370 mg/m2) and LV (200 mg/m2), i.v. bolus daily x 5 days, with escalating doses of IFN-gamma (10-100 micro g/m2) s.c. on days 1, 3, and 5, every 28 days. Twenty-five patients with carcinomas were enrolled; 6 patients received IFN-gamma on days 1 and 3 only. The dose-limiting toxicity, stomatitis, occurred most frequently at 100 micro g/m2 IFN-gamma. Minor response or SD was observed in 2 of 9 patients and in 4 of 12 patients at dose levels of < or =50 micro g/m2 and > or =75 micro g/m2 IFN-gamma, respectively. Three evaluable chemonaive patients demonstrated partial response (2) or complete response (1). Serial plasma samples revealed peak FUra concentrations of >100 micro M; at 100 micro g/m2 IFN-gamma plasma concentrations >5 units/ml persisted for 6.5 h and >1 unit/ml for 28.5 h. The pharmacokinetic parameters of IFN-gamma correlated with a 2-3-fold up-regulation of Fas expression at 24 h in CD15+ cells in peripheral blood samples. Furthermore, clinically relevant IFN-gamma concentrations up-regulated Fas expression and sensitized HT29 colon carcinoma cells in vitro to FUra/LV cytotoxicity. On the basis of the modulation of Fas signaling, FUra/LV combined with IFN-gamma has shown activity in a Phase I trial in colorectal carcinoma and warrants additional evaluation in Phase II.

Activity and toxicity of oxaliplatin and bolus fluorouracil plus leucovorin in pretreated colorectal cancer patients: a phase II study.

The aim of the current study was to evaluate the activity and toxicity of a combination of oxaliplatin with bolus fluorouracil and leucovorin in colorectal cancer (CRC) patients pretreated for advanced disease with various schedules including continuous fluorouracil infusion. Thirty consecutive patients with pretreated advanced CRC received oxaliplatin 130 mg/m2 by 2-h infusion dl, leucovorin 100 mg/m2 by 1-h infusion followed by fluorouracil 425 mg/m2 i.v. bolus from day 1 to 3 every 3 weeks for a maximum of 6 cycles. The best overall response rate in an intent-to-treat analysis was 13% (2 complete responses and 2 partial responses) (95% CI, 1.2-25.5%) and 37% of patients obtained stable disease with a tumor growth control rate of 50% (95% CI, 32.1-67.9%). The median progression-free survival was 4.0 months (95% CI, 1.4-6.5 months) and median overall survival was 12.0 months (95% CI, 9.9-14.1 months). The independent prognostic factors for improved overall survival were a good performance status and a response/stabilization of disease to chemotherapy. Severe neutropenia was quite common (43.3% of patients and 14.4% of cycles), although complicated by fever only in one case (3.3% of patients). There was one toxic death. In conclusion, the study combination showed an interesting rate of tumor growth control in a cohort of patients previously treated for advanced disease with various schedules including continuous fluorouracil infusion.

Therapeutic efficacy and toxicity of bolus application of chemotherapy protocol in the treatment of metastatic colorectal cancer.

AIM: To compare efficacy and toxicity of bolus application of chemotherapy protocol, oxaliplatin, fluorouracil (bolus), leucovorin (folfox) between two groups of patients in the therapy of metastatic colorectal carcinoma (mCRC). METHODS: A total of 63 patients were treated for mCRC in the period January 2009 - January 2010 at the Department of Oncology of the Cantonal Hospital Zenica, Bosnia and Herzegovina (first group, 30 patients) and at the Department of Oncology of the Clinical Hospital Centre Bezanijska kosa in Belgrade, Serbia, in the period January 2005 - January 2006 (second group, 33 patients). The patients were treated according the same protocol, i.v. bolus infusion, but in different day intervals (D), 1, 8, 15/28 days or D1-D5/28 days, respectively. In all patients the following factors were analyzed: tumor response, overall survival (OS), progression free survival, hematological and non-hematological toxicity . RESULTS: Colon was the primary localization in almost two thirds of patients. There was no statistically significant difference between the groups according to the age, hematological and non-hematological toxicity, as well as in achieved OS. Progression free survival expressed in months was in average 5 months though with a large range between minimal and maximal survival time. CONCLUSION: Both groups have shown equivalent efficacy to applied chemotherapy protocols. Overall survival in the two groups matched data from the literature. Further research should confirm success of the combination of chemotherapy protocols and their combination with the biological therapy.

Antitumour effects of pure diastereoisomers of 5-formyltetrahydrofolate in hepatic transplants of a rodent colon carcinoma model.

The effects of the two diastereoisomers of 5-formyltetrahydrofolate on tumour growth, thymidylate synthase (TS, EC 2.1.1.45) levels, and potentiation of 5-fluorouracil cytotoxicity were studied in an in vivo rat colon carcinoma model, transplanted to liver. The animals were randomized into eight groups, treated with daily i.v. tail vein injections of racemic (d,l)-5-formyltetrahydrofolate (5-CHO-FH4), 15 mg/kg, (1)-5-CHO-FH4 7.5 mg/kg, and (d)-5-CHO-FH4 7.5 mg/kg, 5-fluorouracil (FUra) 30 mg/kg, (d,l)-5-CHO-FH4 15 mg/kg+FUra 30 mg/kg, (l) 5-CHO-FH4 7.5 mg/kg+FUra 30 mg/kg, and (d)-5-CHO-FH4 7.5 mg/kg+FUra 30 mg/kg, and a sham-treated control group. The average tumour size of the groups was equal at the start of treatment. After six days' treatment the average tumour sizes were at laparotomy 3.3 +/- 1.0 g in the (d/l)-5-CHO-FH4 treated group, compared to 2.0 +/- 0.1 g in the FUra treated group and 7.1 +/- 3.1 g in the controls. Natural (l)-5-CHO-FH4 promoted tumour growth (average tumour weight 10.8 +/- 4.0 g), whereas the unnatural (d)-5-CHO-FH4 alone retarded it (average tumour weight 1.2 +/- 0.40 g). (l)-5-CHO-FH4 induced a significant increase in tumour tissue TS levels by [3H]FdUMP radioligand assay (27.5 +/- 8.4 pmol/g tumour tissue) compared to controls (16.8 +/- 6.1 pmol/g tumour tissue). Increases in 5,10-methylenetetrahydrofolate and tetrahydrofolate occurred with FUra alone, with a further statistically significant increase in both folates with the addition of (d)-5-CHO-FH4 to FUra.