Isolated hypoxic hepatic perfusion with tumor necrosis factor-alpha, melphalan, and mitomycin C using balloon catheter techniques: a pharmacokinetic study in pigs

Retrograde-outflow percutaneous isolated hepatic perfusion using cisplatin: A pilot study on pharmacokinetics and feasibility

OBJECTIVES

This study aimed to evaluate the feasibility and underlying pharmacokinetics of the retrograde-outflow technique for percutaneous isolated hepatic perfusion (PIHP).

METHODS

Retrograde-outflow PIHP was performed in 12 male pigs (weight, 37-44 kg) by redirecting hepatic outflow through the portal vein. Blood with cisplatin (2.5 mg/kg) in an extracorporeal circuit was circulated through the liver under isolation using rotary pumps with balloon catheters. Hepatic angiographic examinations were conducted during perfusion, and histopathological examinations of the organs were conducted after perfusion. The maximum platinum concentration (C max), area under the concentration-time curve (AUC), and chronologic laboratory data were measured.

RESULTS

Retrograde-outflow isolated hepatic angiography confirmed that contrast media flowed into the portal veins in all 12 pigs. The hepatic veins and inferior vena cava were not opacified. Hepatic C max (86.3 mg/l) was 39-fold greater than systemic C max (2.2 mg/l), and hepatic AUC (1330.8 min · mg/l) was 30-fold greater than systemic AUC (44.6 min · mg/l). Histopathological examinations revealed no ischaemic changes or other abnormalities in the liver, duodenum, small intestine, or colon. Within 1 week of the procedure, chronologic laboratory data (n = 3) normalized or returned to pre-therapy levels.

CONCLUSIONS

The retrograde-outflow technique appears to enable safe and feasible PIHP therapy.

KEY POINTS

• The portal vein acted as an outflow tract under retrograde-outflow PIHP. • Plasma hepatic-to-systemic exposure ratio was 39.2 for the maximum platinum concentration. • Plasma hepatic-to-systemic exposure ratio was 29.8 for the AUC. • The retrograde-outflow technique appears to enable safe and feasible PIHP.

Isolated hepatic perfusion: principles and results

INTRODUCTION

Isolated hepatic perfusion allows the delivery of high dose chemotherapy while decreasing extra-hepatic toxicity, and is used mainly for patients with surgically unresectable liver tumors.

PRINCIPLES

Vascular exclusion of the liver is performed after obtaining satisfactory hemodynamic tolerance, occasionally after cavocaval shunt and/or porto-systemic shunt. Perfusion entry can be arterial and/or portal while the exit is portal or caval. The perfusion circuit can be open or closed, using a circulation pump with or without oxygenation. The chemotherapy regimens used are high dose melphalan (with or without TNF-alpha), oxaliplatin, cisplatin and mitomycin, sometimes associated with moderate hyperthermia. The duration of perfusion ranges between 30 and 90 minutes according to the different protocols used. A percutaneous technique with incomplete liver vascular exclusion is also possible.

RESULTS

The larger series in the literature show a response rate (partial or complete stabilization) between 60 and 80%, with approximately 5% complete morphologic responses. Morbidity and mortality are 40 and 5%, respectively, including specific morbidity related to the perfusion procedure as well as to chemotherapy.

CONCLUSION

Chemotherapy delivered through isolated hepatic perfusion is a new therapeutic alternative, still under development, and can be proposed to patients with surgically unresectable primary or secondary liver tumors within clinical trials. These results seem to be promising, but are still associated with a non-negligible morbidity rate.

Recent trends and future perspectives in isolated hepatic perfusion in the treatment of liver tumors

Isolated hepatic perfusion (IHP) involves a method of complete vascular isolation of the liver to enable treatment of liver tumors with high drug doses without systemic toxicity. Recent clinical studies have mainly employed IHP with melphalan with or without tumor necrosis factor-alpha and mild hyperthermia. The results of these studies demonstrate that high response and survival rates can be achieved with IHP. The current status, recent developments and future perspectives of IHP are discussed in this review.

Locoregional intravascular viral therapy of cancer: precision guidance for Paris's arrow?

Viral therapy of cancer includes strategies such as viral transduction of tumour cells with 'suicide genes', using viral infection to trigger immune-mediated tumour cell death and using oncolytic viruses for their direct anti-tumour action. However, problems still remain in terms of adequate viral delivery to tumours. A role is also emerging for single-organ isolation and perfusion. Having begun with the advent of isolated limb perfusion for extremity malignancy, experimental systems have been developed for the perfusion of other organs, particularly the liver, kidneys and lungs. These are beginning to be adopted into clinical treatment pathways. The combination of these two modalities is potentially significant. Locoregional perfusion increases the exposure of tumour cells to viral agents. In addition, the avoidance of systemic elimination through the immune and reticulo-endothelial systems should provide a mechanism for increased transduction/infection of target cells. The translation of laboratory research to clinical practice would occur within the context of perfusion programmes, which are already established in the clinic. Many of these programmes include the use of vasoactive cytokines such as tumour necrosis factor-alpha, which may have an effect on viral uptake. Evidence of activation of specific anti-tumour immunological responses by intratumoural and other existing methods of viral administration raises the intriguing possibility of a locoregional therapy, with the ability to affect distant sites of disease. In this review, we examined the state of the literature in this area and summarized current findings before indicating likely areas of continuing interest.

Isolated hepatic perfusion for the treatment of liver tumors: sunset or sunrise?

Experience with isolated hepatic perfusion (IHP) is limited to a few centers in the world because of the technical difficulties, surgery-related morbidity, and unproved efficacy in randomized trials. Experimental animal IHP models have led to exploring new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biologic or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable and even repeatable.

Laboratory models of regional chemotherapy

Development of new treatment strategies and agents is a difficult and costly matter in oncology. Routinely drugs are tested in vitro on tumor cells which, however, may have limited predictive value for their activity in patients. Also, the pharmacokinetic behavior, intratumoral distribution, as well as toxic side effects, binding to other compounds and stability of an agent are very important in determining activity in the patient. More so, development and evaluation of surgical delivery methods, i.e. regional treatment strategies, cannot be tested in cell systems. Therefore animal models are crucial for the development of regional chemotherapy methodologies. To allow translation of the animal data to patients it is important that the animal model closely mimics the clinical setting as for instance is achieved with isolated limb perfusion. However, animal models remain limited in their use, as eventually the efficacy of the approach may be different in animals compared to patients. Here we describe the use of animal models for regional treatment of solid tumors.

Isolated hypoxic hepatic perfusion with retrograde outflow in patients with irresectable liver metastases; a new simplified technique in isolated hepatic perfusion

Background

Isolated hepatic perfusion with high-dose chemotherapy is a treatment option for patients with irresectable metastases confined to the liver. Prolonged local control and impact on survival have been claimed. Major drawbacks are magnitude and costs of the procedure. We developed an isolated hypoxic hepatic perfusion (IHHP) with retrograde outflow without the need for a heart-lung machine.

Patients and Methods

Twenty-four consecutive patients with irresectable metastases of various origins were treated. IHHP inflow was via the hepatic artery, outflow via the portal vein with occlusion of the retrohepatic caval vein. Radiolabeled albumine was used for leakage monitoring. Melphalan was used at 1–2 mg/kg. A 25-minute perfusion period was followed by a complete washout. Local and systemic melphalan concentrations were determined.

Results

Compared with oxygenated classical IHP, the IHPP procedure reduced operation time from >8 h to 4 hours, blood loss from >4000 to 900 cc and saved material and personnel costs. Leakage was 0% with negligible systemic toxicity and 0% perioperative mortality. Tumor response: complete response (CR) in 4%, partial response (PR) in 58%, and stable disease (SD) in 13%. Median time to progression was 9 months (2–24 months); pharmacokinetics demonstrated intrahepatic melphalan concentrations more than 9 fold higher than postperfusion systemic concentrations.

Conclusions

IHPP is a relatively simple procedure with reduced costs, reduced blood loss, no mortality, limited toxicity, and response rates comparable to classic IHP. The median duration of 9 months of tumor control should be improved. Hereto, vasoactive drugs, will be explored in further studies.

Synergistic antitumor effects of histamine plus melphalan in isolated hepatic perfusion for liver metastases

BACKGROUND

Nonresectable primary and metastatic liver tumors remain an important clinical problem. Melphalan-based isolated hepatic perfusion (M-IHP) leads to more than 70% objective responses in selective groups of patients with nonresectable metastases confined to the liver. Complete responses are rare and progression-free survival is limited. Tumor necrosis factor (TNF), a very active agent in isolated limb perfusion, is linked to serious hepatotoxicity, restricting its use in IHP. Because of its vasoactive properties, histamine (Hi) is an alternative to TNF. In this article we evaluate its potential synergistic effect in M-IHP, improving response rates.

METHODS

Our experimental rat IHP model is used for the treatment of soft tissue sarcoma liver metastases. Blood samples are collected for monitoring liver enzymes. Livers are excised 72 h and 7 days after treatment for histologic evaluation.

RESULTS

After sham-IHP and Hi-IHP, tumor progression was observed in 100% of treated animals, while after M-IHP this number fell to 62% and after Hi + M-IHP it fell to only 22% (P = 0.006). Overall response rates were of 55% for Hi + M-IHP vs. 25% for M-IHP, and, more importantly, complete responses (CR) were observed only after Hi + M-IHP (22%) (P = 0.009). Hepatotoxicity peaked within 24 h after IHP, independent of the treatment administered, recovered in 48 h, and was related mainly to the elevation of transaminases (grade 3 ASAT and grade 1 ALAT for control group and grades 3 and 4, respectively, for all other treatments). No serious systemic toxicity was observed. Histology of the liver showed no serious damage.

CONCLUSION

Hi + M-IHP has synergistic antitumor effects without any increase in regional or systemic toxicity.

Endovascular isolated hepatic perfusion under pneumoperitoneum

AIMS

Isolated hepatic perfusion (IHP) allows loco-regional administration of high drug doses for cancer treatment. Minimally invasive endovascular occlusion techniques can be used for IHP, but control of leakage remains a major drawback. We hypothesized that the increased intraabdominal pressure generated by a CO(2)-pneumoperitoneum (PP) can reduce the leakage rate of hypoxic endovascular IHP by mechanical compression of the capillary beds connecting the liver to the systemic circulation.

METHODS

IHP was performed on adult pigs through laparotomy using a fenestrated double balloon-catheter placed into the retrohepatic vena cava to collect the hepatic outflow which was reinfused into the hepatic artery through an extracorporeal circulation system. Each pig underwent IHP during four consecutive phases: abdomen open (Phase I), abdomen closed under a 15 and 20 mmHg pneumoperitoneum (Phase II and III, respectively) and abdomen re-opened (Phase IV). The leakage rate from the liver to the systemic circulation was continuously monitored using a nuclear medicine technique. The systemic arterial pressure, the IHP inflow and outflow pressures and the flow rate were recorded.

RESULTS

Leakage from the hepatic extracorporeal circulation to the systemic circulation occurred in all animals during Phase I. Under PP (Phases II and III), two leakage profiles were observed: (1) a major increase of the leakage rate in two animals with a high differential pressure (>50 mmHg) between the IHP inflow and the systemic pressures; (2) no change or a decrease of the leakage rate in the other three animals who had a low or negative differential pressure (<30 mmHg). Leakage was undetectable in all animals after exsufflation of the PP (Phase IV).

CONCLUSIONS

IHP under PP is feasible. Leakage is not reduced during PP. A high gradient between the IHP inflow and the systemic pressure increases systemic leakage during PP. Upon release of the PP, the leakage is most likely redirected towards the volume depleted low resistance portal territory.

Bio-chemotherapeutic strategies and the (dis) utility of hypoxic perfusion of liver, abdomen and pelvis using balloon catheter techniques

AIMS

To review the development and current status of balloon catheter mediated hypoxic perfusion of abdomen, pelvis and liver for treatment of locally advanced malignancies. Within this context we focus on the addition of tumour necrosis factor-alpha (TNF) to these minimal invasive perfusion procedures.

METHODS

A literature search on these topics was carried out in PubMed for indexed articles and in all issues of Regional Cancer Treatment. The findings were related to our own experiences.

RESULTS

Hypoxic abdominal (HAP) and hypoxic pelvic perfusion (HPP) using balloon catheters, are currently applied modalities for treatment of a wide variety of abdominal and pelvic tumours, yet scientific validation of these procedures is poor. Following the results of several Phase I-II trials, both treatments are associated with severe systemic toxicity, significant morbidity and even mortality. The degree of systemic leakage associated with these procedures prohibits addition of TNF. For leakage free liver perfusion surgery is still required, as with current balloon catheter techniques it is not possible to perform leakage free isolated hypoxic hepatic perfusion (IHHP), using either orthograde or retrograde hepatic flow. Experimental and clinical observations suggest that within any perfusion setting, the utilization of TNF is only indicated for treatment of highly vascularised tumours and not for treatment of colorectal tumours.

CONCLUSION

Balloon catheter technology in its present form does not provide adequate leakage control in any of these settings and is therefore associated with considerable toxicity. It is associated with poor response rates and cannot be considered in any setting as a standard of care.

Balloon catheter hypoxic pelvic perfusion with mitomycin C and melphalan for locally advanced tumours in the pelvic region: A phase I—II trial

AIMS

To investigate the feasibility of hypoxic pelvic perfusion (HPP), using balloon catheter techniques as treatment modality for locally advanced pelvic malignancies.

METHODS

In a phase I--II study, 16 patients with various non-resectable pelvic tumours were treated with two HPP with MMC and melphalan, followed by radiotherapy (25 Gy) and surgical resection if feasible. Toxicity and procedure related complications were documented. Tumour responses were assessed by MRI or CT. Pain reductive effects were assessed by evaluation of pain registration forms.

RESULTS

HPP resulted in augmented regional drug concentrations with relatively low systemic levels. Some severe systemic toxicity was observed. One procedure related death occurred. Pain reduction effects were short-lived. Ten patients had radiological NC, two PD and one PR. In 11 patients surgical resection was performed, which was microscopically radical in six cases. Mean survival was 26.8 months (range 1--86).

CONCLUSION

The seemingly favorable pharmacokinetic profiles observed with HPP in this and other studies can still lead to severe systemic toxicity. In terms of survival, local (re-)recurrence and pain reduction there seems no benefit of addition of HPP to pre-operative radiotherapy. HPP with MMC and melphalan, does not seem a therapeutic option in patients with locally advanced pelvic tumours.

Liposomal Cytokines in the Treatment of Infectious Diseases and Cancer

Despite of the demonstrated activity of cytokines in vitro, their use in the clinical setting is often disappointing. Cytokine-related toxicity seriously limits optimal use in vivo. In addition, rapid degradation and excretion, neutralization and binding to receptors, or metabolization of the molecule results in a short half-life in serum when injected intravenously. As the dose-response curve of cytokines is relatively steep, outcome greatly benefits from improved delivery and bioavailability. One way to improve the pharmacokinetics of cytokines after systemic application is encapsulation in liposomes. An advantage of liposomes is that the encapsulated drug is protected from (rapid) degradation and excretion, and it eliminates the binding to neutralizing antibodies or (soluble) receptors. Moreover, liposomes can be tailored in such a way that they exhibit favorable pharmacokinetics, i.e., increased serum half-life and improved targeting to tissues or cells of interest. In this chapter, the use of liposomal cytokines in the treatment of cancer and infectious disease is discussed.

Impaired neutralising antibody formation and high transduction efficacy after isolated hepatic perfusion with adenoviral vectors

Local adenoviral gene transfer can be performed by means of isolated hepatic perfusion (IHP). This methodology is a very effective and safe way to deliver adenoviral vectors. We studied the immune response after IHP. A decreased neutralising antibody formation was observed, offering possibilities for further research in the field of gene therapy in isolated perfusion settings.

Isolated hepatic perfusion for the treatment of colorectal metastases confined to the liver: recent trends and perspectives

Isolated hepatic perfusion (IHP) involves a method of complete vascular isolation of the liver to allow treatment of liver tumours with toxic systemic doses. The recent clinical studies mainly employed IHP with melphalan with or without tumour necrosis factor-alpha (TNF-alpha) and mild hyperthermia. The results of these studies show that high response rates and high survival rates can be achieved by IHP. In this article, the current status, recent developments and future perspectives of IHP are discussed.

Balloon catheter hypoxic abdominal perfusion with Mitomycin C and Melphalan for locally advanced pancreatic cancer: a phase I-II trial

BACKGROUND

Developments in balloon catheter methodology have made hypoxic abdominal perfusion (HAP) with anti-tumour agents possible with only minimal invasive surgery. The initial reports on this modality and celiac axis stop-flow infusion for treatment of pancreatic cancer were very promising in terms of tumour response, median survival and pain reduction. Recent reports, however, have not been able to confirm these results and some have disputed the efficacy of these currently still applied treatment modalities.

METHODS

Twenty-one patients with advanced pancreatic carcinoma were included in a phase I-II trial of HAP with MMC and Melphalan followed by celiac axis infusion (CAI) with the same agents six weeks later. Tumour response was assessed by abdominal-CT and by determining tumour markers. Effect on pain reduction was assessed by evaluation of pain registration forms.

RESULTS

HAP resulted in augmented regional drug concentrations. One patient died after CAI due to acute mesenterial ischaemia. One agent-toxicity related death was observed in the phase-I study. Significant hematological toxicity was observed after HAP and CAI at MTD. No patients were considered resectable after treatment. Median survival after HAP was 6 months (range 1-29). Pain reduction was experienced by only 5/18 patients and was short-lived.

CONCLUSION

In contrast to earlier reports HAP and CAI with MMC and Melphalan did not demonstrate any benefit in terms of tumour response, median survival and pain reduction, compared to less invasive treatment options. As this treatment was associated with significant toxic side-effects and even one procedure related death, we do not consider this a therapeutic option in patients with advanced pancreatic cancer.

Isolated hypoxic hepatic perfusion with orthograde or retrograde flow in patients with irresectable liver metastases using percutaneous balloon catheter techniques: a phase I and II study

BACKGROUND

Isolated hepatic perfusion for irresectable metastases confined to the liver has reported response rates of 50% to 75%. Magnitude, costs, and nonrepeatability of the procedure are its major drawbacks. We developed a less invasive, less costly, and potentially repeatable balloon catheter-mediated isolated hypoxic hepatic perfusion (IHHP) technique.

METHODS

In this phase I and II study, 18 consecutive patients with irresectable colorectal or ocular melanoma hepatic metastases were included. Two different perfusion methods were used, both with inflow via the hepatic artery, using melphalan 1 mg/kg. In the first eight patients, the portal vein was occluded, and outflow was via the hepatic veins into an intracaval double-balloon catheter. This orthograde IHHP had on average 56% leakage. In next 10 patients, we performed a retrograde outflow IHHP with a triple balloon blocking outflow into the caval vein and allowing outflow via the portal vein. The retrograde IHHP still had 35% leakage on average.

RESULTS

Although local drug concentrations were high with retrograde IHHP, systemic toxicity was still moderate to severe. Partial responses were seen in 12% and stable disease in 81% of patients. The median time to local progression was 4.8 months.

CONCLUSIONS

We have abandoned occlusion balloon methodology for IHHP because it failed to obtain leakage control. We are presently conducting a study using a simplified surgical retrograde IHHP method, in which leakage is fully controlled, which translates into high response rates.

True versus mild hyperthermia during isolated hepatic perfusion: effects on melphalan pharmacokinetics and liver function

Hyperthermic antiblastic isolated hepatic perfusion (IHP) with melphalan has been recently proposed as an alternative therapeutic option for patients with unresectable liver tumors. Although melphalan-heat antiblastic synergism is at a maximum at temperatures higher than 41 degrees C, IHP has so far been performed in humans at lower temperatures. In this experimental work, we compared IHP under mild versus true hyperthermic conditions in terms of drug pharmacokinetics and liver function. Ten pigs were submitted to IHP with melphalan 1.5 mg/kg at a mean temperature of 40 degrees C (group A, n = 5) or 42 degrees C (group B, n = 5). After a 60-minute perfusion, a 15-minute washout was performed. Perfusate-to-plasma leakage was monitored using scintigraphy. Throughout perfusion, samples from the systemic blood, perfusate, and liver parenchyma were obtained to measure melphalan concentrations. Liver function was assessed using standard blood tests and the indocyanine green-based test. No deaths related to the IHP procedure were recorded. All animals had transient liver function impairment, with all liver function test results returning to normal within the observation period. At histologic examination, liver damage was similar under both hyperthermic conditions. Melphalan levels in the perfusate were not significantly different in the two study groups (the mean perfusate/plasma area under the curve from 0 to 60 minutes ratios were 463 and 501, respectively). These results correlated well with those obtained using the scintigraphic method. Liver drug concentrations remained unchanged after true hyperthermia IHP. Under true hyperthermic conditions, neither an increase in liver parenchyma toxicity nor changes in melphalan pharmacokinetics were observed. These findings support the use of true hyperthermia in the clinical setting to exploit fully the antitumor synergism between melphalan and heat.

Balloon catheter hypoxic abdominal and pelvic perfusion with tumour necrosis factor-alpha, Melphalan and Mitomycin C: a pharmacokinetic study in pigs

BACKGROUND

Addition of tumour necrosis factor-alpha (TNF) to hypoxic abdominal perfusion (HAP) and hypoxic pelvic perfusion (HPP) with chemotherapeutic agents for treatment of un-resectable malignancies may lead to similar enhanced anti-tumour effects as are observed when TNF is added to isolated limb perfusions (ILP) with Melphalan. Here, we validate the methodology of HAP and HPP using balloon catheter techniques, and investigate the distribution of TNF, Melphalan and Mitomycin C (MMC) over the regional and systemic blood compartments when applying these techniques.

MATERIALS AND METHODS

Twelve pigs underwent HAP or HPP with TNF, Melphalan and MMC for 20 min. Throughout and after the procedures blood samples were obtained from hepatic, portal and systemic blood compartments and plasma concentrations of perfused agents were determined.

RESULTS

We demonstrated that HAP and HPP result in temporary loco-regional concentration advantages of all perfused agents, although from start of perfusion significant systemic leakage occurred.

CONCLUSION

On basis of these results it seems that the advantage in terms of regional plasma concentration of TNF may be insufficient for TNF-mediated effects to occur, making future addition of this cytokine to these procedures in the clinical setting questionable. The observed regional concentration advantages of MMC and Melphalan, however, warrant further studies on clinical application of these agents in both settings.

Isolated hepatic perfusion: experimental evidence and clinical utility

Many patients with tumors confined to the liver are not amenable for surgical resection, and an increasing number of these patients are treated by local ablation methods. Isolated hepatic perfusion is another treatment option especially suitable for patients with multiple or bulky primary or metastatic tumors. and can mediate clinical regression of advanced liver metastases. Experience with IHP is still limited to a few centers in the world because of its technical difficulties, surgery-related morbidity, and unproven efficacy. IHP remains an experimental modality restricted to specialized units dedicated to treating this difficult group of patients. Experimental animal IHP models have led us to explore new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biological or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable.

An experimental minimally invasive perfusion technique for the treatment of liver metastases

AIM

Isolated hepatic perfusion (IHP) is an invasive, technically difficult, non-repeatable and demanding operation. In this study we report the development of a less invasive alternative for the surgical IHP in a pig model.

METHODS

Our technique was tested in 8 Yorkshire pigs (60 kg). The liver was isolated from the systemic circuit using minimally invasive techniques: an occlusion stent-graft and balloon catheters, with reversal of the blood flow through the liver during IHP.

RESULTS

Tests with varying pressures applied at the PV revealed a clear relation between the suction pressure at the outflow site (PV), intrahepatic pressure and systemic leakage of 99mTc. A leakage-free IHP could be obtained in seven separate experiments.

CONCLUSION

Isolated hepatic perfusion using minimally invasive techniques is feasible in pigs when the intrahepatic pressure is controlled. This technique has yet to be tested in patients.

Solid tumor therapy: manipulation of the vasculature with TNF

Drug delivery to solid tumors is one of the most challenging aspects in cancer therapy. Whereas agents seem promising in the test tube, clinical trials often fail due to unfavorable pharmacokinetics, poor delivery, low local concentrations, and limited accumulation in the target cell. A major step forwards in the treatment of solid tumors is the recognition of the tumor-associated vasculature as an important target for therapy. Inhibition of tumor vascular development has a direct effect on the growth and progression of the tumor. Destruction of an existing vasculature also directly inflicts serious damage to the tumor cell. Moreover, the tumor vascular bed can be manipulated facilitating enhanced permissiveness of the tumor for administered chemotherapeutics. In this review, we focus on the use of tumor necrosis factor alpha (TNF) in local and systemic therapy in conjunction with chemotherapy. In these settings TNF demonstrates potent and selective activity on the tumor vascular bed, which strongly improves tumor response.

Isolated liver perfusion for non-resectable liver tumours: a review

Many treatments have been proposed for non-resectable primary or secondary hepatic cancer but the results have generally been disappointing. Isolated Hepatic Perfusion (IHP) was first attempted four decades ago but it gained acceptance only recently, after spectacular tumour responses were obtained by isolated limb perfusion with melphalan and tumour necrosis factor (TNF) for melanomas and sarcomas. Surgical isolation of the liver is a technically demanding operation that allows the safe administration of high doses of chemotherapeutics and TNF. Percutaneous techniques using balloon occlusion catheters are simpler but result in higher leakage rates from the perfusion circuit into the systemic circulation. Several phase I-II trials indicate that IHP can yield high tumour response rates, even when there is resistance to systemic chemotherapy. However, no significant advantage in overall survival has been demonstrated so far. IHP offers unique pharmacokinetic advantages for locoregional chemotherapy and biotherapy. It might also allow gene therapy with limited systemic exposure and toxicity. At present, IHP nevertheless remains an experimental treatment modality which should therefore be used in controlled trials only.

Reduced liver uptake of arterially infused melphalan during retrograde rat liver perfusion with unaffected liver tumor uptake

Isolated hepatic perfusion (IHP) with melphalan is used for patients with nonresectable metastases confined to the liver. To improve the efficacy of IHP and to reduce the toxicity to the liver, reversion (retrograde perfusion) of the bloodstream through the liver in a rat model was studied. For liver tumor induction male WAG/Rij rats were inoculated with CC531 cells, a colorectal tumor cell line. After 11 to 12 days the tumor-bearing rat livers were perfused by single-pass perfusion through either the portal (orthograde) or caval vein (retrograde) for different time periods. During perfusion melphalan (160 Schultze) was infused in the hepatic artery. Melphalan concentrations were measured by high-performance liquid chromatography. A rapid extraction of melphalan by the liver occurred in the first 5 min, reaching steady state after 10 to 20 min for both perfusion directions. The melphalan concentration of the outflow perfusate was significantly higher in the retrograde perfusion compared with the orthograde perfusion. The melphalan content of the tumor tissue was unaffected by perfusion direction at any time point. To the contrary, the melphalan uptake in liver tissue was strongly influenced: the melphalan content after 40-min retrograde perfusion was 12% of that after orthograde perfusion. The average tumor/liver concentration ratio was 6 for orthograde perfusion and 30 for retrograde perfusion. In conclusion, retrograde IHP with continuous melphalan infusion in the hepatic artery provides a high tumor uptake of melphalan with potentially reduced liver toxicity compared with orthograde IHP.

Stop-flow technique for loco-regional delivery of antiblastic agents: literature review and personal experience

AIMS

The therapeutic approach for primary or recurrent advanced solid tumours, particularly when unresectable, is still one of the main medical challenges in the management of cancer patients. The stop-flow (SF) technique has been recently proposed as a semi-invasive drug delivery system based on the blood supply blockage of the tumour-bearing area. Here, we discuss the principles underlying the SF technique as well as the worldwide experience published so far. We also report on the results of our pilot study on pelvic and limb SF perfusion.

METHODS

We reviewed the worldwide experience on SF as reported by the literature published on PubMed from 1990 through 2001. In our series, we treated 20 patients affected with locally advanced melanoma, soft tissue sarcoma or colorectal cancer.

RESULTS

This therapeutic modality - at least for some tumours - can achieve encouraging results in terms of clinical response even after conventional therapies have failed. Moreover, as a safe and relatively simple procedure, SF can be applied to patients for whom traditional treatments (i.e. surgery, systemic chemotherapy) are contraindicated because of poor general conditions.

CONCLUSIONS

At present, the SF technique should be considered an investigational approach to locally advanced cancers. The encouraging results obtained with this procedure should be validated by large phase III trials.

Intratumoral administration of low doses of an adenovirus vector encoding tumor necrosis factor alpha together with naive dendritic cells elicits significant suppression of tumor growth without toxicity

Although tumor necrosis factor alpha (TNF-alpha) is a potent cytokine with a myriad of innate immune antitumor properties, systemic administration of TNF-alpha is associated with significant toxicity, limiting the use of the TNF-alpha protein as an antitumor therapeutic. On the basis of the knowledge that dendritic cells (DCs) play a central role in initiating antitumor adaptive immune responses, we hypothesized that intratumoral administration of low doses of an adenovirus encoding TNF-alpha (AdTNF-alpha) together with syngeneic DCs would act synergistically to suppress preexisting tumors. As a model, four different tumor cell lines, all resistant in vitro to the TNF-alpha protein, were implanted in syngeneic mice, and established tumors received intratumor AdTNF-alpha alone or in combination with DCs. At high doses (10(9) PFU), AdTNF-alpha alone suppressed tumor growth, but was associated with systemic toxicity. A 100-fold lower AdTNF-alpha concentration (10(7) PFU) or high doses of the control vector AdNull had no systemic toxicity, but also minimal suppression of tumor growth. In contrast, local administration of the low dose (10(7) PFU) of AdTNF-alpha in combination with syngeneic DCs (AdTNF-alpha + DCs) elicited marked tumor suppression without toxicity. Administration of AdTNF-alpha + DCs into tumors elicited tumor-specific cytotoxic T cells and protected animals against subsequent challenge with the same tumor, suggesting that AdTNF-alpha + DC therapy induced tumor-specific adaptive immune host responses. Consistent with this concept, studies with syngeneic knockout mice showed that MHC class I molecules on DCs as well as CD8(+) T cells were necessary for the antitumor effect of intratumor AdTNF-alpha + DCs. These data demonstrate that the combination of intratumoral administration of the TNF-alpha cDNA together with naive DCs can evoke tumor suppression without systemic toxicity, providing a new paradigm for the use of TNF-alpha as antitumor therapy.

Tumor necrosis factor-alpha augments tumor effects in isolated hepatic perfusion with melphalan in a rat sarcoma model

Isolated hepatic perfusion (IHP) is an attractive approach to treating nonresectable liver tumors, because the effects of systemic chemotherapy are poor and its application is hampered by severe general toxicity. In clinical and experimental settings, the efficacy of isolated limb perfusion (ILP) with tumor necrosis factor-alpha (TNF alpha) in combination with melphalan to treat melanoma in transit and soft-tissue sarcoma has been well established. In an ILP model in rats, the authors previously observed synergistic anti-tumor effects of TNF and melphalan on BN 175 soft-tissue sarcoma extremity tumors. The aim of the current study was to determine whether similar synergy in anti-tumor effects could be achieved by treating experimental BN 175 soft-tissue sarcoma liver tumors by IHP using these agents. The authors found that IHP with TNF and melphalan resulted in a dramatic increase in regional concentrations of perfused agents with virtually no concomitant systemic leakage. Isolated hepatic perfusion with only carrier solution resulted in a significantly diminished growth rate of BN 175 liver tumors compared with the growth rate of tumors in nonperfused rats. Perfusion with melphalan alone resulted in minimal anti-tumor effects. Perfusion with only TNF had a slight growth-stimulatory effect on the BN 175 liver tumors, but no negative effects on tumor growth were observed. When TNF was added to melphalan, a dramatic anti-tumor effect was observed. Thus, as in the rat ILP setting, the anti-tumor effect is augmented when TNF is added to IHP with melphalan to treat BN 175 soft-tissue sarcoma tumor-bearing rats. Strikingly, the tumor response was potentiated at relatively low concentrations of TNF compared with concentrations that elicited synergy with melphalan in ILP.

[Chemotherapy by isolated liver perfusion with endovascular occlusion catheter: preliminary experience in pigs]

Very high concentrations of cytotoxic drug may be obtained with chemotherapy performed with vascular exclusion.

OBJECTIVE

To study the pharmacokinetics and toxicity of melphalan during in situ isolated liver perfusion, and to test an endovascular occlusion catheter.

METHODS

Isolated liver perfusion with melphalan (15 mg bolus) was performed in 6 pigs (50-60 kg) for 30 min, with non-oxygenated Ringer's solution. Hepatic outflow, collected by a double balloon catheter inserted into the retrohepatic inferior vena cava, was pumped into the gastroduodenal artery, while the common hepatic artery and portal vein were clamped.

RESULTS

A maximum concentration of 30,000 ng/mL was obtained in the circuit before an exponential decrease, while the concentration in systemic blood was less than 500 ng/mL (n = 3). Before closing the abdomen, melphalan concentrations were about 2,000 ng/mg in the liver, and undetectable in the muscle. Postoperative course (2 weeks, n = 2) was uneventful with minor alterations in blood tests and hepatic histology.

CONCLUSION

This method of local chemotherapy with melphalan appears to be safe with minor leakage and minimal toxicity.

Significance of duplex/colour Doppler sonography in hepatic arterial chemotherapy for patients with liver metastases from colorectal carcinoma

AIMS

The aim of the study was to evaluate the importance of duplex/colour Doppler ultrasound in a protocol of hepatic regional chemotherapy, by measuring the blood flow in the hepatic artery, portal vein, hepatic veins, and inferior caval vein of patients with unresectable liver metastases from colorectal carcinoma.

METHODS

Thirty-nine consecutive subjects were selected for this study, including 21 patients who had unresectable histologically confirmed liver metastases from colorectal carcinoma (Group A), and 18 asymptomatic volunteers as normal controls (Group B). All subjects of Groups A and B were examined using duplex/colour Doppler sonography. After the ultrasound study, all patients of Group A were submitted to the administration of high dose mitomycin C into the hepatic artery, with concomitant detoxication of post-hepatic venous blood.

RESULTS

The mean value of the hepatic artery blood flow was significantly higher (P=0.0009) in liver metastases patients (361 ml/min, SEM=24 ml/min) than in normal controls (245 ml/min, SEM=20 ml/min). Also, the mean Doppler perfusion index was higher in liver metastases patients than in normal controls. For each patient of Group A, the total dose of mitomycin C to be infused was calculated based on the blood flow in the hepatic artery. In this way the concentration of mitomycin C in the hepatic artery was always greater than 3 microg/ml. The duration of detoxication was calculated based on the blood flow in the inferior caval vein. For two patients only, the blood flow was lower than 1000 ml/min, with the necessity to protract the duration of detoxication over 2 hours.

CONCLUSIONS

The measurement of the blood flow in hepatic vessels of patients with liver metastases seems to be very important in establishing the total dose of drug which has to be infused in hepatic arterial chemotherapy, and to determine the duration of concomitant detoxication of post-hepatic venous blood.

Increased local cytostatic drug exposure by isolated hepatic perfusion: a phase I clinical and pharmacologic evaluation of treatment with high dose melphalan in patients with colorectal cancer confined to the liver

A phase I dose-escalation study was performed to determine whether isolated hepatic perfusion (IHP) with melphalan (L-PAM) allows exposure of the liver to much higher drug concentrations than clinically achievable after systemic administration and leads to higher tumour concentrations of L-PAM. Twenty-four patients with colorectal cancer confined to the liver were treated with L-PAM dosages escalating from 0.5 to 4.0 mg kg(-1). During all IHP procedures, leakage of perfusate was monitored. Duration of IHP was aimed at 60 min, but was shortened in eight cases as a result of leakage from the isolated circuit. From these, three patients developed WHO grade 3-4 leukopenia and two patients died due to sepsis. A reversible elevation of liver enzymes and bilirubin was seen in the majority of patients. Only one patient was treated with 4.0 mg kg(-1) L-PAM, who died 8 days after IHP as a result of multiple-organ failure. A statistically significant correlation was found between the dose of L-PAM, peak L-PAM concentrations in perfusate (R = 0.86, P< or =0.001), perfusate area under the concentration-time curve (AUC; R = 0.82, P<0.001), tumour tissue concentrations of L-PAM (R = 0.83, P = 0.011) and patient survival (R = 0.52, P = 0.02). The peak L-PAM concentration and AUC of L-PAM in perfusate at dose level 3.0 mg kg(-1) (n = 5) were respectively 35- and 13-fold higher than in the systemic circulation, and respectively 30- and 5-fold higher than reported for high dose oral L-PAM (80-157 mg m(-2)) and autologous bone marrow transplantation. Median survival after IHP (n = 21) was 19 months and the overall response rate was 29% (17 assessable patients; one complete and four partial remissions). Thus, the maximally tolerated dose of L-PAM delivered via IHP is approximately 3.0 mg kg(-1), leading to high L-PAM concentrations at the target side. Because of the complexity of this treatment modality, IHP has at present no place in routine clinical practice.