Doxifluridine in colorectal cancer patients resistant to 5-fluorouracil (5-FU) containing regimens

Folate Conjugated Polyethylene Glycol Probe for Tumor-Targeted Drug Delivery of 5-Fluorouracil

A targeted delivery system is primarily intended to carry a potent anticancer drug to specific tumor sites within the bodily tissues. In the present study, a carrier system has been designed using folic acid (FA), bis-amine polyethylene glycol (PEG), and an anticancer drug, 5-fluorouracil (5-FU). FA and PEG were joined via an amide bond, and the resulting FA-PEG-NH₂ was coupled to 5-FU producing folate-polyethylene glycol conjugated 5-fluorouracil (FA-PEG-5-FU). Spectroscopic techniques (UV-Vis, ¹HNMR, FTIR, and HPLC) were used for the characterization of products. Prodrug (FA-PEG-5-FU) was analyzed for drug release profile (in vitro) up to 10 days and compared to a standard anticancer drug (5-FU). Folate conjugate was also analyzed to study its folate receptors (FR) mediated transport and in vitro cytotoxicity assays using HeLa cancer cells/Vero cells, respectively, and antitumor activity in tumor-bearing mice models. Folate conjugate showed steady drug release patterns and improved uptake in the HeLa cancer cells than Vero cells. Folate conjugate treated mice group showed smaller tumor volumes; specifically after the 15th day post-treatment, tumor sizes were decreased significantly compared to the standard drug group (5-FU). Molecular docking findings demonstrated importance of Trp138, Trp140, and Lys136 in the stabilization of flexible loop flanking the active site. The folic acid conjugated probe has shown the potential of targeted drug delivery and sustained release of anticancer drug to tumor lesions with intact antitumor efficacy.

Fluoropyrimidines in the Treatment of Advanced Neoplastic Diseases: Role and Advantages of UFT

The fluoropyrimidine antimetabolites were employed in a wide range of neoplastic diseases. In particular, 5-fluorouracil in association with other chemotherapeutic agents, or biochemical modulators was successfully used in the treatment of colorectal, gastric, breast, head and neck cancers. With this type of chemotherapy, a response rate ≤ 20% was obtained in gastrointestinal tumors, without a statistically significant impact on the overall survival.

UFT is a combination of tegafur an uracil, which has the important advantage of an improved oral bioavailability, if we compare it with 5-fluorouracil. Uracil, avoiding the fluoropyrimidine degradation inside the tumor cells, increases the permanence of the metabolically active fluropyrimidine into the target cell, so having an improvement in the therapeutic activity.

A very large spectrum of cancers were treated with this molecule. In particular, a response rate in the range of 20–40% was observed in the treatment of patients with metastatic colorectal cancer.

Phase III trials are ongoing to evaluate the advantage on 5-FU of this new fluoropyrimidine in terms of clinical efficacy, and quality of life, considering the possibility to administer it orally.

Oral versus intravenous fluoropyrimidines for colorectal cancer

BACKGROUND

Patients prefer oral to intravenous (IV) palliative chemotherapy, provided that oral therapy is not less effective. We compared the efficacy and safety of oral and IV fluoropyrimidines for treatment of colorectal cancer (CRC).

OBJECTIVES

To compare the effects of oral and IV fluoropyrimidine chemotherapy in patients treated with curative or palliative intent for CRC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5), along with OVID MEDLINE, OVID Embase, and Web of Science databases, in June 2016. We also searched five clinical trials registers, several conference proceedings, and reference lists from study reports and systematic reviews. We contacted pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing oral and IV fluoropyrimidine chemotherapy in patients treated with curative or palliative intent for CRC.

DATA COLLECTION AND ANALYSIS

Three review authors extracted data and assessed risk of bias independently. We assessed the seven domains in the Cochrane 'Risk of bias' tool and three additional domains: schedules of outcome assessment and/or follow-up; use of intention-to-treat analysis; and baseline comparability of treatment arms.

MAIN RESULTS

We included nine RCTs (total of 10,918 participants) that examined treatment with curative intent for CRC with neoadjuvant and/or adjuvant chemotherapy. We included 35 RCTs (total of 12,592 participants) that examined treatment with palliative intent for inoperable advanced or metastatic CRC with chemotherapy (31 first-line studies, two second-line studies, and two studies of first- or second-line chemotherapy). All studies included male and female participants, and no studies included participants younger than 18 years of age. Patients treated with curative intent for CRC with neoadjuvant and/or adjuvant chemotherapy • Disease-free survival (DFS): DFS did not differ between participants treated with oral versus IV fluoropyrimidines (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.87 to 1.00; seven studies, 8903 participants; moderate-quality evidence).• Overall survival (OS): OS did not differ between participants treated with oral versus IV fluoropyrimidines (HR 0.92, 95% CI 0.84 to 1.00; seven studies, 8902 participants analysed; high-quality evidence).• Grade ≥ 3 adverse events (AEs): Participants treated with oral fluoropyrimidines experienced less grade ≥ 3 neutropenia/granulocytopenia (odds ratio (OR) 0.14, 95% CI 0.11 to 0.16; seven studies, 8087 participants; moderate-quality evidence), stomatitis (OR 0.21, 95% CI 0.14 to 0.30; five studies, 4212 participants; low-quality evidence), and any grade ≥ 3 AEs (OR 0.82, 95% CI 0.74 to 0.90; five studies, 7741 participants; low-quality evidence). There was more grade ≥ 3 hand foot syndrome (OR 4.59, 95% CI 2.97 to 7.10; five studies, 5731 participants; low-quality evidence) in patients treated with oral fluoropyrimidines. There were no differences between participants treated with oral versus IV fluoropyrimidines in occurrence of grade ≥ 3 diarrhoea (OR 1.12, 95% CI 0.99 to 1.25; nine studies, 9551 participants; very low-quality evidence), febrile neutropenia (OR 0.59, 95% CI 0.18 to 1.90; four studies, 2925 participants; low-quality evidence), vomiting (OR 1.05, 95% CI 0.83 to 1.34; eight studies, 9385 participants; low-quality evidence), nausea (OR 1.21, 95% CI 0.97 to 1.51; seven studies, 9233 participants; low-quality evidence), mucositis (OR 0.64, 95% CI 0.25 to 1.62; four studies, 2233 participants; very low-quality evidence), and hyperbilirubinaemia (OR 1.67, 95% CI 0.52 to 5.38; three studies, 2757 participants; very low-quality evidence). Patients treated with palliative intent for inoperable advanced or metastatic CRC with chemotherapy • Progression-free survival (PFS): Overall, PFS was inferior in participants treated with oral versus IV fluoropyrimidines (HR 1.06, 95% CI 1.02 to 1.11; 23 studies, 9927 participants; moderate-quality evidence). Whilst PFS was worse in participants treated with oral compared with IV fluoropyrimidines when UFT/Ftorafur or eniluracil with oral 5-fluorouracil (5-FU) was used, PFS did not differ between individuals treated with oral versus IV fluoropyrimidines when capecitabine, doxifluridine, or S-1 was used.• OS: Overall, OS did not differ between participants treated with oral versus IV fluoropyrimidines (HR 1.02, 95% CI 0.99 to 1.05; 29 studies, 12,079 participants; high-quality evidence). OS was inferior in participants treated with oral versus IV fluoropyrimidines when eniluracil with oral 5-fluorouracil (5-FU) was used.• Time to progression (TTP): TTP was inferior in participants treated with oral versus IV fluoropyrimidines (HR 1.07, 95% CI 1.01 to 1.14; six studies, 1970 participants; moderate-quality evidence).• Objective response rate (ORR): ORR did not differ between participants treated with oral versus IV fluoropyrimidines (OR 0.98, 95% CI 0.90 to 1.06; 32 studies, 11,115 participants; moderate-quality evidence).• Grade ≥ 3 AEs: Participants treated with oral fluoropyrimidines experienced less grade ≥ 3 neutropenia/granulocytopenia (OR 0.17, 95% CI 0.15 to 0.18; 29 studies, 11,794 participants; low-quality evidence), febrile neutropenia (OR 0.27, 95% CI 0.21 to 0.36; 19 studies, 9407 participants; moderate-quality evidence), stomatitis (OR 0.26, 95% CI 0.20 to 0.33; 21 studies, 8718 participants; low-quality evidence), mucositis (OR 0.17, 95% CI 0.12 to 0.24; 12 studies, 4962 participants; low-quality evidence), and any grade ≥ 3 AEs (OR 0.83, 95% CI 0.74 to 0.94; 14 studies, 5436 participants; low-quality evidence). There was more grade ≥ 3 diarrhoea (OR 1.66, 95% CI 1.50 to 1.84; 30 studies, 11,997 participants; low-quality evidence) and hand foot syndrome (OR 3.92, 95% CI 2.84 to 5.43; 18 studies, 6481 participants; moderate-quality evidence) in the oral fluoropyrimidine arm. There were no differences between oral and IV fluoropyrimidine arms in terms of grade ≥ 3 vomiting (OR 1.18, 95% CI 1.00 to 1.40; 23 studies, 9528 participants; low-quality evidence), nausea (OR 1.16, 95% CI 0.99 to 1.36; 25 studies, 9796 participants; low-quality evidence), and hyperbilirubinaemia (OR 1.62, 95% CI 0.99 to 2.64; nine studies, 2699 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

Results of this review should provide confidence that treatment for CRC with most of the oral fluoropyrimidines commonly used in current clinical practice is similarly efficacious to treatment with IV fluoropyrimidines. Treatment with eniluracil with oral 5-FU was associated with inferior PFS and OS among participants treated with palliative intent for CRC, and eniluracil is no longer being developed. Oral and IV fluoropyrimidines have different patterns of side effects; future research may focus on determining the basis for these differences.

5-Fluorouracil concentration in blood, liver and tumor tissues and apoptosis of tumor cells after preoperative oral 5’-deoxy-5-fluorouridine in patients with hepatocellular carcinoma

AIM: To study the levels of 5-fluorouracail (5-FU) in plasma, liver and tumor in patients with hepatocellular carcinoma after oral administration of 5’-deoxy-5-fluorouridine (5’-DFUR).

METHODS: Thirty-nine patients with hepatocellular carcinoma were treated with oral 5’-DFUR for more than 4 d before operation. The contents of 5-FU in plasma, liver and tumor were measured by high performance liquid chromatography (HPLC) and apoptosis of tumor cells was evaluated by in-situ TUNEL after resection of tumor.

RESULTS: The concentrations of 5-FU were 1.1 μg/mL, 5.6, 5.9, and 10.5 μg/g in plasma, the liver tissue, the center of tumor and the periphery of tumor, respectively. 5-FU concentration was significantly higher in the periphery of tumor than that in the liver tissue and the center of tumor (10.5 ± 1.6 μg/g vs 5.6 ± 0.8 μg/g, t = 21.38, P < 0.05; 10.5 ± 1.6 μg/g vs 5.9 ± 0.9 μg/g, t = 20.07, P < 0.05). 5-FU level was significantly lower in plasma than that in the liver and the tumor (1.1 ± 0.3 μg/mL vs 5.6 ± 0.8 μg/g, t = 19.63, P < 0.05; 1.1 ± 0.3 μg/mL vs 10.5 ± 1.6 μg/g, t = 41.01, P < 0.05). Apoptosis of tumor cells was significantly increased after oral 5’-DFUR compared to the control group without 5’-DFUR treatment.

CONCLUSION: There is a higher concentration of 5-FU distributed in the tumor compared with liver tissue and apoptosis of tumor cells is increased following oral 5’-DFUR compared with the control group. The results indicate that 5’-DFUR is hopeful as neo-adjuvant chemotherapy to prevent recurrence after resection of hepatocellular carcinoma.

A study of purified montmorillonite intercalated with 5-fluorouracil as drug carrier

Since its introduction over 40 years ago, 5-fluorouracil (5-FU) has remained the only effective chemotherapy option available for the treatment of colorectal cancer (CRC). However, this cytotoxic anticancer drug often causes severe side effects because it does not act selectively on the tumor. It has been reported that the 5-FU showed considerable toxicity when administered by intravenous injections or via alimentary tract. Although, many materials have been developed for carrying 5-FU, there has been no clinically acceptable carrier for 5-FU till now. Montmorillonite, one of the clay minerals, consists of hydrated aluminum silicates with fine grains and large spaces between the layers. Isomorphous substitution of cations is common. In the study, we attempt to intercalate 5-FU into interlayers of montmorillonite through ion exchange. Montmorillonite was purified from crude clays of bentonite in Tai-dong, Taiwan by filtration and sedimentation. Solutions of 5-FU with different concentrations were prepared by dissolving various amounts of 5-FU into 10 ml NaOH solution. Purified montmorillonite powder was soaked in 5-FU solution for a period of time with different pH values and temperatures. In this study, we try to intercalate 5-FU into interlayers of montmorillonite to find out optimum conditions, such as soaking time, temperature, pH value, initial 5-FU concentration, etc., to prepare composites of 5-FU and montmorillonite (5-FU/mont). UV, SDT, FTIR, XRD are used to characterize the 5-FU/mont composite. From the results. 5-FU was successfully intercalated into the interlayer of montmorillonite both by free surface absorption and OH replacement. The optimum condition for 5-FU/mont preparations is 1.185 wt% of 5-FU as initial concentration under a pH value of 11.6 at a temperature of 80 degrees C and a soaking time of 2 h. The total amount of 5-FU in montmorillonite is about 87.5 mg for each gram of montmorillonite, which can be proved by thermal gravimetric analysis. The composite of 5-FU/mont is expected to achieve in situ release for colorectal cancer therapy in future applications.

Clinical pharmacology of anticancer agents in relation to formulations and administration routes

In the past years, alternative administration routes and pharmaceutical formulations of anticancer agents have been investigated in order to improve conventional chemotherapy treatment. The impact of these adjustments on the pharmacokinetics and pharmacodynamics is discussed. A review of the literature shows many examples of alternative administration forms of anticancer agents with improved pharmacokinetics. Local administration routes have been investigated in order to reduce the systemic toxicity and to enhance the local efficacy of conventional chemotherapy. Oral administration of anticancer agents is preferred by patients for its convenience and its potential for outpatient treatment. In addition, oral administration facilitates a prolonged exposure to the cytotoxic agent. However, poor bioavailability and substantial interpatient variability are noted as limitations for oral chemotherapy. Increased tumour selectivity can also be achieved by the use of specific pharmaceutical formulations, such as liposomes and macromolecular drug conjugates. The composition of these formulations often determine the pharmacokinetic behaviour of the formulated drug. In conclusion, several alternative administration forms of anticancer agents have been designed in the past years, with the potential for improvement of conventional chemotherapy, however, more extensive clinical evaluation of these novel strategies is warranted to prove their real clinical value.