Pharmacokinetic study of 5-fluorouracil in a novel dialysate solution: a long-term intraperitoneal treatment approach for advanced colorectal carcinoma

Ability of plasma-activated acetated Ringer's solution to induce A549 cell injury is enhanced by a pre-treatment with histone deacetylase inhibitors

Non-thermal plasma (NTP) is applicable to living cells and has emerged as a novel technology for cancer therapy. NTP affect cells not only by direct irradiation, but also by an indirect treatment with previously prepared plasma-activated liquid. Histone deacetylase (HDAC) inhibitors have the potential to enhance susceptibility to anticancer drugs and radiation because these reagents decondense the compact chromatin structure by neutralizing the positive charge of the histone tail. The aim of the present study was to demonstrate the advantage of the combined application of plasma-activated acetated Ringer’s solution (PAA) and HDAC inhibitors on A549 cancer cells. PAA maintained its ability for at least 1 week stored at any temperature tested. Cell death was enhanced more by combined regimens of PAA and HDAC inhibitors, such as trichostatin A (TSA) and valproic acid (VPA), than by a single PAA treatment and was accompanied by ROS production, DNA breaks, and mitochondria dysfunction through a caspase-independent pathway. These phenomena induced the depletion of ATP and elevations in intracellular calcium concentrations. The sensitivities of HaCaT cells as normal cells to PAA were less than that of A549 cells. These results suggest that HDAC inhibitors synergistically induce the sensitivity of cancer cells to PAA.

Optimal Use of Glucose Polymer (Icodextrin) in Peritoneal Dialysis

The osmotic effectiveness of glucose polymer is now well established. The relative inertness of this macromolecular compound has been the key factor in its success as the first “colloid” osmotic agent in clinical use. In its present form, it produces sustained ultrafiltration for up to 12 hours, and a daily overnight use would obviate the need for hypertonic exchanges, especially 3.86% glucose. In addition, it could be used in automated peritoneal dialysis regimes to enhance ultrafiltration and solute clearance during the daytime. Preliminary reports also indicate that it is beneficial in diabetic patients and in some patients who have lost ultrafiltration. The new “bimodal” formulations look promising, with the potential to replace all the currently used hyperosmolar exchanges with physiological solutions.

Although systemic accumulation of glucose polymer breakdown products occurs, it reaches steadystate levels quickly (within two weeks) and remains stable throughout the duration of polymer use. In the long-term study, these levels of maltose and oligosaccharides over three-and-a-half years represent the longest exposure of these substances in uremic patients without any clinical or metabolic adverse effects and provide an important evidence of safety.

Future work based on studies that are ongoing suggest that a family of physiological solutions (“bimodal” preparations in iso-osmolar combination) could be available, and the individual's dialysis prescription could be tailored to take into account the ultrafiltration, metabolic needs, as well as the longterm viability of the membrane. Glucose polymer will be a key component of such solutions.

Icodextrin: Overview of Clinical Experience

Objective

To review all clinical studies and experience gained with icodextrin to date; primarily its use in peritoneal dialysis in patients with end-stage renal failure, but also its use as an intraperitoneal vehicle.

Data sources

Peer-reviewed original research articles in the literature; abstracts from international scientific meetings; data generated from the compassionate use programme.

Study selection

All published studies to date are included, some 10–20 studies being included in this review.

Data extraction

Data have not been specifically extracted from studies; results have been described in the context of overall experience.

Results

Over ten years of clinical experience with icodextrin have now been accumulated, in both continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). A small number of patients have received icodextrin for over five years, with no loss of effect. Icodextrin produces sustained ultrafiltration over long dwells while being iso-osmolar, by the process of colloid osmosis.

Conclusion

Icodextrin represents the first viable alternative osmotic agent to glucose, for use in solutions for peritoneal dialysis. It also has a potential use as a vehicle solution for intraperitoneal drug delivery.

Synthesis and Activity of a Novel Autotaxin Inhibitor-Icodextrin Conjugate

Autotaxin is an extracellular phospholipase D that catalyzes the hydrolysis of lysophosphatidyl choline (LPC) to generate the bioactive lipid lysophosphatidic acid (LPA). Autotaxin has been implicated in many pathological processes relevant to cancer. Intraperitoneal administration of an autotaxin inhibitor may benefit patients with ovarian cancer; however, low molecular mass compounds are known to be rapidly cleared from the peritoneal cavity. Icodextrin is a polymer that is already in clinical use because it is slowly eliminated from the peritoneal cavity. Herein we report conjugation of the autotaxin inhibitor HA155 to icodextrin. The conjugate inhibits autotaxin activity (IC₅₀ = 0.86 ± 0.13 μg mL^-1) and reduces cell migration. Conjugation of the inhibitor increased its solubility, decreased its membrane permeability, and improved its intraperitoneal retention in mice. These observations demonstrate the first application of icodextrin as a covalently-bonded drug delivery platform with potential use in the treatment of ovarian cancer.

Reduction of carcinomatosis risk using icodextrin as a carrier solution of intraperitoneal oxaliplatin chemotherapy

There is no standard treatment in patients with high risk metachronous peritoneal carcinomatosis (PC) in colonic cancer, as perforated tumour or synchronous ovarian metastasis. Icodextrin 4% (ICDX), presently used to prevent postoperative abdominal adhesions, could inhibit the coactivation of the tumour cells and the microenvironment cells, associated with the development of PC. The aim of this study was to inhibit the formation of the PC in a murine model mimicking surgical situation using ICDX and intraperitoneal (IP) prophylactic chemotherapy. We created a model of growing PC in mice using cells of murine colonic cancer CT26. Cells and treatments were injected simultaneously. Five groups were created: CT26 (control group), CT26 + ICDX (ICDX group), CT26 + chemotherapy (oxaliplatin and 5FU) (chemo group), CT26 + chemotherapy + ICDX (ICDX chemo group), ICDX (toxicity group). At day 15, PC was evaluated with rodents PCI. In the chemo group, PCI was significantly lower than in the control group (3.2 versus 8.4, p = 0.02). ICDX had a synergetic effect on PC with chemotherapy; indeed PCI in ICDX chemo group was lower than in chemo group (1.4 versus 3.2, p = 0.04). There was no morbidity linked to ICDX in toxicity group. Safety of ICDX needs to be verified, particularly on colonic anastomosis before ICDX associated to IP chemotherapy could be used as a preventive treatment of PC in high risk patients. This prophylactic treatment is easy to use and would be administrated at the end of a curative surgery for a colonic cancer.

Surgery for colorectal peritoneal carcinomatosis

Peritoneal carcinomatosis occurs in patients with advanced gastrointestinal and gynecological malignancies and also in patients who experience recurrence after treatment failure of the primary tumor. Malignant disease in the peritoneal cavity is a morbid and significant predictor of a diminished survival in a cancer patient. Systemic chemotherapy alone will not be adequate to palliate or treat patients with peritoneal carcinomatosis. Cytoreductive surgery is a new surgical technique that is performed using peritonectomy procedures to allow total eradication of peritoneal tumors. Intraperitoneal chemotherapy regimens such as intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) and early postoperative intraperitoneal chemotherapy (EPIC) are effective adjuvant treatment to treat the minimal residual disease after cytoreductive surgery to reduce the risk of locoregional recurrence. A substantial body of evidence available in the current literature has documented the survival benefits of combining cytoreductive surgery and intraperitoneal chemotherapy to treat a previously fatal phase of malignancy. This review provides a summary of the developments in the understanding and treatment of peritoneal surface malignancy from colorectal cancer.

Oncolytic adenoviral gene therapy in ovarian cancer: why we are not wasting our time

Preclinical gene-therapy studies in the past 15 years have repeatedly raised hopes that we were about to enter a brave new era. However, many clinical trials have disappointed. For tumor types with poor response rates to first-line conventional cytotoxic chemotherapy and/or high rates of chemorefractory disease, there remain very few treatment options. In this article we review gene therapy within the context of ovarian cancer. We examine why clinical data have been discouraging and discuss how the lessons learned from earlier trials are being applied to current research.

Drugs, carrier solutions and temperature in hyperthermic intraperitoneal chemotherapy

At the Fifth International Workshop on Peritoneal Surface Malignancy, in Milan, the consensus on technical aspects of cytoreductive surgery (CRS) for peritoneal surface malignancy was obtained through the Delphi process. Conflicting points concerning drugs, carrier solution and optimal temperature for hyperthermic intraperitoneal chemotherapy (HIPEC) were discussed.

Pharmacokinetics and tissue distribution of intraperitoneal 5-fluorouracil with a novel carrier solution in rats

AIM: To compare the pharmacokinetics and tissue distribution of 5-fluorouracil administered intraperitoneally with two isotonic carrier solutions: HAES-steri (neotype 6% hydroxyethyl starch), a novel carrier solution with middle molecular weight and physiologic saline (0.9% sodium chloride solution), a traditional carrier solution for intraperitoneal chemotherapy, in rats.

METHODS: A total of 60 Sprague Dawley rats were randomized into groups according to the carrier solution administered. Each group was further randomized according to the intraperitoneal dwell period (1, 3, 6, 12, 18 and 24 h). At the end of the procedure the rats were killed, the peritoneal fluid was withdrawn completely and quantitated. Drug concentrations in peritoneal fluid, plasma, and tissues were determined by high-performance liquid chromatography.

RESULTS: The mean volumes remaining in the peritoneal cavity were significantly higher with HAES-steri than those with physiologic saline at 1, 6, 12, 18, and 24 h (P = 0.047, 0.009, 0.005, 0.005 and 0.005 respectively, the percentages of remaining peritoneal fluid volume were 89.9 ± 5.6 vs 83.4 ± 4.9, 79.9 ± 2.8 vs 56.2 ± 15.7, 46.8 ± 5.5 vs 24.7 ± 9.7, 23.0 ± 2.8 vs 0.0 ± 0.0 and 4.2 ± 1.7 vs 0.0 ± 0.0 respectively). Mean concentrations in peritoneal fluid were significantly higher with HAES-steri than those with physiologic saline at 3, 12 and 18 h (P = 0.009, 0.009 and 0.005 respectively, the concentrations were 139.2768 ± 28.2317 mg/L vs mg/L, 11.5427 ± 3.0976 mg/L vs 0.0000 ± 0.0000 mg/L and 4.7724 ± 1.0936 mg/L vs 0.0000 ± 0.0000 mg/L respectively). Mean plasma 5-fluorouracil concentrations in portal vein were significantly higher with HAES-steri at 3, 12, 18 and 24 h (P = 0.009, 0.034, 0.005 and 0.019 respectively, the concentrations were 3.3572 ± 0.8128 mg/L vs 0.8794 ± 0.2394 mg/L, 0.6203 ± 0.9935 mg/L vs 0.0112 ± 0.0250 mg/L, 0.3725 ± 0.3871 mg/L vs 0.0000 ± 0.0000 mg/L, and 0.2469 ± 0.1457 mg/L vs 0.0000 ± 0.0000 mg/L respectively), but significantly lower at 1 h (P = 0.009, the concentrations were 4.1957 ± 0.6952 mg/L vs 7.7406 ± 1.2377 mg/L). There were no significant differences in the plasma 5-fluorouracil in inferior caval vein at each time-point. 5-fluorouracil concentrations were significantly greater with HAES-steri at 18 h in gastric tissue (P = 0.016, the concentrations were 0.9486 ± 0.8173 mg/L vs 030392 ± 0.0316 mg/L), at 18 h in colon (P = 0.009, the concentrations were 0.1730 ± 0.0446 mg/L vs 0.0626 ± 0.0425 mg/L), at 3, 6, 12 and 24 h in liver (P = 0.009, 0.013, 0.034 and 0.013 respectively, the concentrations were 0.6472685 ± 0.5256 mg/L vs 0.1554 ± 0.1043mg/L, 0.8606826 ± 0.7155 mg/L vs 0.0014 ± 0.0029 mg/L, 0.0445 ± 0.0330 mg/L vs 0.0797 ± 0.1005 mg/L and 0.0863 ± 0.0399 mg/L vs 0.0034 ± 0.0075 mg/L respectively) and at 18 h in lung (P = 0.009, the concentrations were 0.0886 ± 0.0668 mg/L vs 0.0094 ± 0.0210 mg/L). There were no differences in 5-fluorouracil concentrations in renal tissue at each time-point.

CONCLUSION: The use of intraperitoneal 5-fluoro-uracil with HAES-Steri carrier solution provides a pharmacokinetic advantage for a local-regional killing of residual tumor cells and improve the accumulated penetrability of 5-fluorouracil with decreased systemic toxicity. Further clinical feasibility studies on the use of HAES-steri as carrier solution for intraperitoneal chemotherapy with 5-fluorouracil are warranted.

Carrier solutions for intraperitoneal chemotherapy

Two pharmacokinetic problems appear to limit the effectiveness of intraperitoneal therapy: poor tumor penetration and nonuniform intraperitoneal distribution by the drug-containing solution. A better understanding of the pharmacodynamics of carrier solutions for intraperitoneal chemotherapy may impact on both these problems. Not only is the choice of drug important, but also the matching of the chosen drug to an appropriate carrier solution. It would appear that high molecular weight solutions offer a number of advantages over low molecular weight glucose and saline solutions for chemotherapeutic agents that have a high molecular weight with a slow peritoneal clearance. The use of carrier solutions of varying tonicity requires further investigation.

Development of a formulation that enhances gene expression and efficacy following intraperitoneal administration in rabbits and mice

We conducted a series of experiments to determine if intraperitoneal (IP) delivery of recombinant adenovirus (rAd)-based therapies is improved through carrier vehicle selection, and compared an icodextrin solution (a high molecular weight dextrin with a prolonged peritoneal cavity residence time) with a standardized phosphate buffered saline (PBS) delivery solution. In vitro, comparative adenovirus particle concentration determination (27 h) and bioactivity assay (24h) indicated equivalent compatibility with icodextrin or PBS. In vivo, rabbits treated IP (100 ml) with rAd-betagal 1 x 10(9) P/ml in icodextrin showed improved transgene expression throughout the peritoneal wall compared to rAd-betagal in PBS. In PC-3 tumor-bearing mice treated IP with 5 x 10(9) P/0.5 ml or 1 x 10(10) P/0.5 ml rAd-betagal, transgene expression was significantly enhanced (p < 0.01) with icodextrin compared to PBS in both tumor specimens and peritoneal wall. In subsequent studies we compared prolongation of survival in intraperitoneal PC-3 and MDAH-2774 human xenograft tumor models in nude mice using rAd-p53 in icodextrin or PBS in multi-dose ranging (1 x 10(8) to 1 x 10(10) P) experiments. The icodextrin formulation alone significantly increased rAd-p53 mediated survival (p < 0.05). In animals, these results show that IP rAd gene therapy can be improved with the use of icodextrin, and suggest that prolonged retention and distribution in the peritoneal cavity is an important factor.

A pilot study of adjuvant intraperitoneal 5-fluorouracil using 4% icodextrin as a novel carrier solution

AIM

This pilot study utilised the sustained intraperitoneal (i.p.) dwell properties of an iso-osmotic solution of 4% icodextrin to investigate the tolerability, toxicity and feasibility of home-based i.p. 5FU adjuvant chemotherapy following resective surgery for colorectal cancer.

METHODS

Twenty eligible patients (Dukes' stage B and C with potentially curative resection) underwent perioperative Tenckhoff catheter placement. Ten (6 male, 4 female, aged 46-85; mean 67.5 years) received 5FU chemotherapy. After initial flushing and gradual increase in volumes of 4% icodextrin alone, patients received home-based i.p. 5FU (150-300 mg/m(2)/day given as equal doses at 12-hourly intervals) for 14 days, with a 14-day recovery period, for a maximum of 6 courses. Two incurable patients, treated on compassionate grounds, provided further safety data.

RESULTS

Nine of the 10 patients became proficient in self-treatment with 5FU and two completed 6 courses. Frequent abdominal pain was the main dose-limiting toxicity of 5FU, causing withdrawal of three patients after a high (300 mg/m(2)/day) first course and one following a third course at lower doses. I.p. 5FU concentrations (mean>30000 ngml(-1)) were 1000 fold higher than systemic venous levels. Bacterial peritonitis led to two withdrawals but was not a frequent event (microbiologically confirmed incidence of 1 per 27 catheter-months).

CONCLUSIONS

Home-based i.p. adjuvant chemotherapy is a feasible treatment option in patients with surgically resected colorectal carcinoma.

Prevention of chemotherapy-induced intraperitoneal adhesion formation in rats by icodextrin at a range of concentrations

OBJECTIVE

Two controlled in vivo studies in rats have investigated the effect of icodextrin solution on intraperitoneal chemotherapy-induced adhesion formation. The first study evaluated the effect of three concentrations of icodextrin (4, 15, 20% w/v) in comparison to a phosphate-buffered saline (PBS) control in response to intraperitoneal doxorubicin (n = 40). The second study compared the effect of 4% icodextrin to Ringers' lactate solution (RLS) control in response to intraperitoneal bleomycin (n = 30).

METHODS

Doxorubicin and bleomycin were administered via a continuous pump and as a single bolus (bleomycin only). Doxorubicin 2 ml (23.2 microg/ml) was delivered via pump in conjunction with 20 ml of 4, 15, or 20% icodextrin or PBS (n = 10 per group). In the bleomycin experiments rats received either 2 ml (0.77 U/ml) bleomycin delivered via pump in conjunction with 15 ml 4% icodextrin or RLS, or 0.77 or 0.077 U bleomycin delivered in 15 ml 4% icodextrin or RLS administered as a bolus injection (n = 5 per group). Seven days after the initiation of doxorubicin treatment and 9 days after initiation of bleomycin treatment, the rats were euthanized by CO(2) and the extent of peritoneal adhesion formation was evaluated using an 8-point scoring system.

RESULTS

When icodextrin was administered in conjunction with doxorubicin there was a reduction in the formation of adhesions compared to PBS. Efficacy increased with the concentration of icodextrin used. The lowest dose of bleomycin (0.077 U) caused very few adhesions. Results with bleomycin 0.77 U/ml (pump) and 0.77 U (bolus) showed that 4% icodextrin was significantly more effective than RLS at preventing adhesion formation, irrespective of the dosing regimen.

CONCLUSIONS

These studies suggest that 4% icodextrin may reduce adhesion formation caused by intraperitoneal chemotherapy.

Fluid dynamics in man of an intraperitoneal drug delivery solution: 4% icodextrin

Interest in targeting drugs into the peritoneal cavity for intra-abdominal cancers or infections is undergoing a revival as recent clinical trials have demonstrated, not only a regional advantage in concentration of the active agent, but also improved long-term outcomes. Solutions currently used for intraperitoneal (IP) drug delivery have short residence times, however, which can limit the exposure of all areas of the peritoneum to the active agent. Icodextrin 4% solution was compared with saline and a glucose-based peritoneal dialysis solution in a clinical study of IP residence time. The study was carried out during the fortnightly rest phase in 9 patients undergoing 5-fluorouracil (5-Fu) IP treatment for colorectal cancer. The volume remaining in the peritoneal cavity was measured at 0, 12, 24, 48, 72, and 96 hr after an instillation of 2 liters of each fluid. Saline (n = 3 dwells) and glucose (n = 3 dwells) peritoneal dialysis solutions were almost fully absorbed by 24 hr, and the patients experienced discomfort when using these solutions. In contrast, icodextrin 4% solution (n = 188 dwells) maintained its instilled volume for up to 48 hr, and half the instilled volume remained after 72 and 96 hr. This result would allow extensive and prolonged coverage of the peritoneal surface. Icodextrin 4% solution may be an effective vehicle to deliver therapeutic agents into the peritoneal cavity.

Icodextrin provides long dwell peritoneal dialysis and maintenance of intraperitoneal volume

Icodextrin 7.5% is an isosmolar solution for once-daily use in peritoneal dialysis for patients with end-stage renal failure (ESRF). It produces substantial ultrafiltration (UF), performing best over longer dwells of 8-12 h in continuous ambulatory peritoneal dialysis (CAPD) patients, and up to 16 h in automated peritoneal dialysis (APD) patients. Subsequent use in other clinical areas (ultrafiltration failure) and normal postmarketing clinical experience has established its tolerability and safety profiles; a small number of patients, including those with diabetes, have now received icodextrin for up to 6 years. Icodextrin's ability to maintain intraperitoneal volume over many hours has led to its undergoing development as an intraperitoneal drug delivery system for targeted regional delivery of anticancer drugs and lymphatic delivery of anti-HIV treatment. Isosmolar icodextrin 7.5% solution represents the first major advance in the treatment of ESRF by peritoneal dialysis since the development of CAPD using glucose-based solutions 20 years ago.

Prolonged intraperitoneal infusion of 5-fluorouracil using a novel carrier solution

A novel peritoneal carrier solution, Icodextrin 20 (7.5%), has allowed exploration of prolonged, intraperitoneal (i.p.) infusion of the cytotoxic drug 5-fluorouracil (5-FU). A phase I and pharmacokinetic study was performed to determine the toxicities and maximum tolerated dose of prolonged and continuous intraperitoneal 5-FU in patients with peritoneal carcinomatosis. Seventeen patients were entered into this study. Each patient had a Tenckhoff catheter placed into the peritoneal cavity under general anaesthetic. After initial flushing and gradual increase in exchange volumes with Icodextrin 20, 5-FU was administered daily from Monday to Friday, 50% as a bolus in the exchange bag and 50% in an elastomeric infusor device delivering continuous 5-FU to the peritoneal cavity at 2 ml h-1. Treatment was continued for 12 weeks or until intolerable toxicity developed. Abdominal pain and infective peritonitis proved to be the main dose-limiting toxicities. Initial problems with infective peritonitis were overcome by redesign of the delivery system, and it proved possible to deliver 300 mg m-2 5-FU daily (5 days per week) for 12 weeks. Pharmacokinetic studies showed i.p. steady-state 5-FU concentrations (mean 47 500 ng ml-1) that were > 1000-fold higher than systemic venous levels (mean 30 ng ml-1).