Transarterial chemoembolization of hepatocellular carcinoma. Agents and drugs: an overview. Part 1

Locoregional drug delivery for cancer therapy: Preclinical progress and clinical translation

Systemic drug delivery is the current clinically preferred route for cancer therapy. However, challenges associated with tumor localization and off-tumor toxic effects limit the clinical effectiveness of this route. Locoregional drug delivery is an emerging viable alternative to systemic therapies. With the improvement in real-time imaging technologies and tools for direct access to tumor lesions, the clinical applicability of locoregional drug delivery is becoming more prominent. Theoretically, locoregional treatments can bypass challenges faced by systemic drug delivery. Preclinically, locoregional delivery of drugs has demonstrated enhanced therapeutic efficacy with limited off-target effects while still yielding an abscopal effect. Clinically, an array of locoregional strategies is under investigation for the delivery of drugs ranging in target and size. Locoregional tumor treatment strategies can be classified into two main categories: 1) direct drug infusion via injection or implanted port and 2) extended drug elution via injected or implanted depot. The number of studies investigating locoregional drug delivery strategies for cancer treatment is rising exponentially, in both preclinical and clinical settings, with some approaches approved for clinical use. Here, we highlight key preclinical advances and the clinical relevance of such locoregional delivery strategies in the treatment of cancer. Furthermore, we critically analyze 949 clinical trials involving locoregional drug delivery and discuss emerging trends.

Silk fibroin-based embolic agent for transhepatic artery embolization with multiple therapeutic potentials

BACKGROUND

The excellent physicochemical and biomedical properties make silk fibroin (SF) suitable for the development of biomedical materials. In this research, the silk fibroin microspheres (SFMS) were customized in two size ranges, and then carried gold nanoparticles or doxorubicin to evaluate the performance of drug loading and releasing. Embolization efficiency was evaluated in rat caudal artery and rabbit auricular artery, and the in vivo distribution of iodinated SFMS (125I/131I-SFMS) after embolization of rat hepatic artery was dynamically recorded by SPECT. Transhepatic arterial radioembolization (TARE) with 131I-SFMS was performed on rat models with liver cancer. The whole procedure of selective internal radiation was recorded with SPECT/CT, and the therapeutic effects were evaluated with 18 F-FDG PET/CT. Lastly, the enzymatic degradation was recorded and followed with the evaluation of particle size on clearance of sub-micron silk fibroin.

RESULTS

SFMS were of smooth surface and regular shape with pervasive pores on the surface and inside the microspheres, and of suitable size range for TAE. Drug-loading functionalized SFMS with chemotherapy or radio-sensitization, and the enhanced therapeutic effects were proved in treating HUH-7 cells as lasting doxorubicin release or more lethal radiation. For artery embolization, SFMS effectively blocked the blood supply; when 131I-SFMS serving as the embolic agent, the good labeling stability and embolization performance guaranteed the favorable therapeutic effects in treating in situ liver tumor. At the 5th day post TARE with 37 MBq/3 mg 131I-SFMS per mice, tumor activity was quickly inhibited to a comparable glucose metabolism level with surrounding normal liver. More importantly, for the fragments of biodegradable SFMS, smaller sized SF (< 800 nm) metabolized in gastrointestinal tract and excreted by the urinary system, while SF (> 800 nm) entered the liver within 72 h for further metabolism.

CONCLUSION

The feasibility of SFMS as degradable TARE agent for liver cancer was primarily proved as providing multiple therapeutic potentials.

Enhanced Embolization Efficacy with the Embolic Microspheres Guided by the Aggregate Gradation Theory Through In Vitro and Simulation Evaluation

PURPOSE

Size of the embolic microspheres is of critical importance in the transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) to achieve the optimal embolization therapy. In this regard, to optimize the size distribution of the embolic microspheres and enhance the embolization efficacy, the aggregate gradation theory is used to formulate the microspheres.

METHODS

Finite element analysis (FEA) and in vitro experiments confirmed a better embolic efficacy for the poly(vinyl alcohol) (PVA) microspheres formulated according to the aggregate gradation theory.

RESULTS

The average volume flow of the graded group was 1.31 × 10^-4 mL/s in vitro experiment, which was lowest among all the groups suggesting the graded group had the optimal embolic effect. The graded group has the largest pressure gradient of 314.22 Pa/μm in FEA among all the groups, which can be attributed to the highest packing density of the graded group compared with other groups.

CONCLUSIONS

The graded embolic microspheres have a larger drag coefficient compared with the narrow size distribution groups both in vitro experiment and FEA. These findings can be used to formulate the embolic agents with optimal size distributions and are significant for the improvement of clinical embolization therapy.

Loco-regional drug delivery in oncology: current clinical applications and future translational opportunities

Introduction: Drug-based treatment regimens for cancer are often associated with off-target toxic side effects and low penetration of the drug at the tumor site leading to patient morbidity and limited efficacy. Loco-regional drug delivery has the potential to increase efficacy while concomitantly reducing toxicity.Areas covered: Clinical applications using loco-regional delivery include intra-arterial drug delivery in retinoblastoma, direct intra-tumoral (IT) injection of ethanol for ablation in hepatocellular carcinoma (HCC) and the use of HIPEC in peritoneal carcinomas. In recent years, there has been a significant increase in both approved products and clinical trials, with a particular emphasis on drug delivery platforms such as drug-eluting beads for HCC and hydrogel platforms for intravesical delivery in bladder cancer.Expert opinion: Development of loco-regional drug-delivery systems has been slow, limited by weak clinical data for early applications and challenges relating to dosing, delivery and retention of drugs at the site of action. However, there is increasing focus on the potential of loco-regional drug delivery when combined with bespoke drug-delivery platforms. With the growth in immunotherapies, the use of IT delivery to drive priming of the anti-tumor response has opened up a new field of opportunity for loco-regional drug delivery.

Chitosan Nanoparticles for Therapy and Theranostics of Hepatocellular Carcinoma (HCC) and Liver-Targeting

Chitosan nanoparticles are well-known delivery systems widely used as polymeric carriers in the field of nanomedicine. Chitosan is a carbohydrate of natural origin: it is a biodegradable, biocompatible, mucoadhesive, polycationic polymer and it is endowed with penetration enhancer properties. Furthermore, it can be easily derivatized. Hepatocellular carcinoma (HCC) represents a remarkable health problem because current therapies, that include surgery, liver transplantation, trans-arterial embolization, chemoembolization and chemotherapy, present significant limitations due to the high risk of recurrence, to a lack of drug selectivity and to other serious side effects. Therefore, there is the need for new therapeutic strategies and for improving the liver-targeting to HCC. Nanomedicine consists in the use of nanoscale carriers as delivery systems to target and deliver drugs and/or diagnostic agents to specific organs or tissues. Chitosan and its derivatives can be successfully used in the preparation of nanoparticles that, for their peculiar surface-properties, can specifically interact with liver tumor, by passive and active targeting. This review concerns the use of chitosan nanoparticles for the therapy and theranostics of HCC and liver-targeting.

Transcatheter arterial chemoembolization combined with simultaneous DynaCT-guided radiofrequency ablation in the treatment of solitary large hepatocellular carcinoma

PURPOSE

To introduce the technique and investigate the clinical efficacy of transcatheter arterial chemoembolization (TACE) in combination with simultaneous DynaCT-guided radiofrequency ablation (RFA) in the treatment of solitary large hepatocellular carcinomas (HCCs) (maximal diameter > 5 cm).

MATERIALS AND METHODS

Forty-six patients who received TACE combined with simultaneous DynaCT-guided RFA for solitary large HCCs between January 2012 and August 2016 were reviewed, and the success rate, safety, local tumor progression (LTP), and overall survival (OS) were retrospectively investigated. OS and time to progression were analyzed with the Kaplan-Meier method.

RESULTS

Technical success rate was 100%, average operative time for DynaCT-guided RFA was 45.3 ± 4.8 min, average radiation dose was 730.5 ± 78.8 mGy, and no life-threatening complications were observed. At 1-month follow-up enhanced MRI, complete remission was achieved in 82.6% of patients (38/46), and partial remission in 17.4% (8/46). The median follow-up period was 29.5 months (interquartile range 4.0-69.0 months). At 1, 2, and 3 years after surgery, the LTP rates were 4.3, 13.1, and 30.4%, respectively, and the OS rates were 89.1, 71.7, and 56.5%, respectively.

CONCLUSION

DynaCT-guided TACE + RFA is safe and feasible for the treatment of solitary large HCCS. TACE combined with simultaneous RFA provides a new treatment option for solitary large HCCs in which DynaCT has important clinical value.

Bench-to-clinic development of imageable drug-eluting embolization beads: finding the balance

This review describes the historical development of an imageable spherical embolic agent and focuses on work performed in collaboration between Biocompatibles UK Ltd (a BTG International group company) and the NIH to demonstrate radiopaque bead utility and bring a commercial offering to market that meets a clinical need. Various chemistries have been investigated and multiple prototypes evaluated in search of an optimized product with the right balance of handling and imaging properties. Herein, we describe the steps taken in the development of DC Bead LUMI™, the first commercially available radiopaque drug-eluting bead, ultimately leading to the first human experience of this novel embolic agent in the treatment of liver tumors.

Review of the Development of Methods for Characterization of Microspheres for Use in Embolotherapy: Translating Bench to Cathlab

Therapeutic embolotherapy is the deliberate occlusion of a blood vessel within the body, which can be for the prevention of internal bleeding, stemming of flow through an arteriovenous malformation, or occlusion of blood vessels feeding a tumor. This is achieved using a wide selection of embolic devices such as balloons, coils, gels, glues, and particles. Particulate embolization is often favored for blocking smaller vessels, particularly within hypervascularized tumors, as they are available in calibrated sizes and can be delivered distally via microcatheters for precise occlusion with associated locoregional drug delivery. Embolic performance has been traditionally evaluated using animal models, but with increasing interest in the 3R's (replacement, reduction, refinement), manufacturers, regulators, and clinicians have shown interest in the development of more sophisticated in vitro methods for evaluation and prediction of in vivo performance. Herein the current progress in developing bespoke techniques incorporating physical handling, fluid dynamics, occlusive behavior, and sustained drug elution kinetics within vascular systems is reviewed. While it is necessary to continue to validate the safety of such devices in vivo, great strides have been made in the development of bench tests that better predict the behavior of these products aligned with the principles of the 3R's.

In situ forming biodegradable poly(ε-caprolactone) microsphere systems: a challenge for transarterial embolization therapy. In vitro and preliminary ex vivo studies

BACKGROUND

In situ forming biodegradable poly(ε-caprolactone) (PCL) microspheres (PCL-ISM) system was developed as a novel embolic agent for transarterial embolization (TAE) therapy of hepatocellular carcinoma (HCC). Ibuprofen sodium (Ibu-Na) was loaded on this platform to evaluate its potential for the treatment of post embolization syndrome.

METHODS

The influence of formulation parameters on the size/shape, encapsulation efficiency and drug release was investigated using mixture experimental design. Regression models were derived and used to optimize the formulation for particle size, encapsulation efficiency and drug release profile for TAE therapy. An ex vivo model using isolated rat livers was established to assess the in situ formation of microspheres.

RESULTS

All PCL-ISM components affected the studied properties and fitting indices of the regression models were high (Radj² = 0.810 for size, 0.964 encapsulation efficiency, and 0.993 or 0.971 for drug release at 30 min or 48 h). The optimized composition was: PCL = 4%, NMP = 43.1%, oil = 48.9%, surfactant = 2% and drug = 2%. Ex vivo studies revealed that PCL-ISM was able to form microspheres in the hepatic arterial bed.

CONCLUSIONS

PCL-ISM system provides a novel tool for the treatment of HCC and post-embolization syndrome. It is capable of forming microspheres with desirable size and Ibu-Na release profile after injection into blood vessels.

Changes of HBV DNA After Chemoembolization for Hepatocellular Carcinoma and the Efficacy of Antiviral Treatment

Unlike systemic chemotherapy for hematological malignancies with hepatitis B virus (HBV) infection, transarterial chemoembolization (TACE) for HBV-related hepatocellular carcinoma (HCC) has only recently been reported to cause HBV reactivation and subsequent hepatitis. Most patients with HBV-related HCC have an underlying disease with liver fibrosis or cirrhosis, and TACE may potentially induce HBV reactivation and liver decompensation. Currently, there are no clinical guidelines for managing TACE-caused HBV reactivation. In this review, we summarize the changes of HBV status and liver function after TACE and the effect of antiviral treatment before, during, or after TACE.

Indocyanine green delivery systems for tumour detection and treatments

Indocyanine green (ICG) is a cyanine compound that displays fluorescent properties in the near infrared region. This dye is employed for numerous indications but nowadays its major application field regards tumour diagnosis and treatments. Optical imaging by near infrared fluorescence provides news opportunities for oncologic surgery. The imaging of ICG can be useful for intraoperative identification of several solid tumours and metastases, and sentinel lymph node detection. In addition, ICG can be used as an agent for the destruction of malignant tissue, by virtue of the production of reactive oxygen species and/or induction of a hyperthermia effect under irradiation. Nevertheless, ICG shows several drawbacks, which limit its clinical application. Several formulative strategies have been studied to overcome these problems. The rationale of the development of ICG containing drug delivery systems is to enhance the in vivo stability and biodistribution profile of this dye, allowing tumour accumulation and resulting in better efficacy. In this review, ICG containing nano-sized carriers are classified based on their chemical composition and structure. In addition to nanosystems, different formulations including hydrogel, microsystems and others loaded with ICG will be illustrated. In particular, this report describes the preparation, in vitro characterization and in vivo application of ICG platforms for cancer imaging and treatment. The promising results of all systems confirm their clinical utility but further studies are required prior to evaluating the formulations in human trials.

Liver Malignancies Treated With Intra-Arterial Therapy: Assessment of Early Response as Quantified by Volumetric Enhancement Using Gadoxetate Disodium

OBJECTIVE

The aim of the study was to evaluate the value of volumetric contrast-enhanced magnetic resonance imaging (MRI) using gadoxetate disodium in early assessment of treatment response after intra-arterial therapy (IAT).

MATERIALS AND METHODS

This prospective study included 21 patients (32 malignant lesions) who underwent MRI using gadoxetate disodium before and early after IAT. Two reviewers reported response by anatomic criteria including Response Evaluation Criteria in Solid Tumor (RECIST), Modified RECIST (mRECIST), and European Association for the Study of Liver Disease and functional criteria including volumetric enhancement in hepatic arterial phase and portal venous phase. Treatment end point was RECIST at 6 months. A 2-sample paired t test was used to compare the mean changes after IAT. A P value of less than 0.05 was considered statistically significant.

RESULTS

Responders by RECIST at 6 months did not fulfill partial response by conventional criteria at 1 month, except for mRECIST by reader 2. The mRECIST and European Association for the Study of Liver Disease could not be assessed in a total of 4 and 3 lesions for readers 1 and 2, respectively. However, volumetric measurements were obtained in all lesions and the changes were statistically significant at 1 month for hepatic arterial phase (P = 0.02 and P = 0.008) and portal venous phase (P < 0.0001 and P < 0.0001), as assessed by both readers, respectively.

CONCLUSIONS

Volumetric contrast-enhanced MRI using gadoxetate disodium may be a helpful tool to evaluate early treatment response after IAT in malignant liver tumors.

Development of thermosensitive chitosan/glicerophospate injectable in situ gelling solutions for potential application in intraoperative fluorescence imaging and local therapy of hepatocellular carcinoma: a preliminary study

OBJECTIVES

Thermosensitive chitosan/glycerophosphate (C/GP) solutions exhibiting sol-gel transition around body temperature were prepared to develop a class of injectable hydrogel platforms for the imaging and loco-regional treatment of hepatocellular carcinoma (HCC). Indocyanine green (ICG) was loaded in the thermosensitive solutions in order to assess their potential for the detection of tumor nodules by fluorescence.

METHODS

The gel formation of these formulations as well as their gelling time, injectability, compactness and resistance of gel structure, gelling temperature, storage conditions, biodegradability, and in vitro dye release behavior were investigated. Ex vivo studies were carried out for preliminary evaluation using an isolated bovine liver.

RESULTS

Gel strengths and gelation rates increased with the cross-link density between C and GP. These behaviors are more evident for C/GP solutions, which displayed a gel-like precipitation at 4°C. Furthermore, formulations with the lowest cross-link density between C and GP exhibited the best injectability due to a lower resistance to flow. The loading of the dye did not influence the gelation rate. ICG was not released from the hydrogels because of a strong electrostatic interaction between C and ICG. Ex vivo preliminary studies revealed that these injectable formulations remain in correspondence of the injected site.

CONCLUSIONS

The developed ICG-loaded hydrogels have the potential for intraoperative fluorescence imaging and local therapy of HCC as embolic agents. They form in situ compact gels and have a good potential for filling vessels and/or body cavities.

Single-Agent versus Combination Doxorubicin-Based Transarterial Chemoembolization in the Treatment of Hepatocellular Carcinoma: A Single-Blind, Randomized, Phase II Trial

OBJECTIVES

It was the aim of this study to find an optimal therapeutic regimen of transarterial chemoembolization (TACE) by comparing the efficacy of chemoembolization with different anticancer agents in hepatocellular carcinoma (HCC) patients.

METHODS

A single-blind, three-group parallel, randomized trial was conducted in Guangdong General Hospital, Guangzhou, China, with patients with biopsy-confirmed HCC. Group 1 received single-drug (doxorubicin) chemoembolization, while group 2 received double-drug (doxorubicin and mitomycin C) chemoembolization. Patients in group 3 were treated with triple-drug (doxorubicin, mitomycin C, and gemcitabine) chemoembolization. Lipiodol was used as embolization agent in all protocols. We compared the overall survival (OS), time to progression (TTP), and objective response rate (ORR) between groups. Response assessment was performed according to modified RECIST (Response Evaluation Criteria In Solid Tumors) criteria.

RESULTS

Between January 2008 and January 2011, 162 patients (group 1, n = 50; group 2, n = 59; group 3, n = 53) were recruited. The OS and TTP in groups 1, 2, and 3 were 14.9 and 6.4, 13.2 and 6.4, and 20.5 and 6.8 months, respectively. OS and TTP were statistically significant among groups (p = 0.002 and p = 0.037). The ORR was 22.0, 40.7, and 56.6%, respectively. The ORR was significantly different across the three groups (p < 0.002).

CONCLUSIONS

TACE with multiple chemotherapeutic agents might significantly increase survival and tumor response; additionally, gemcitabine was likely to have an advantage in improving the prognosis of HCC patients. © 2015 S. Karger AG, Basel.

Application of lobaplatin in trans-catheter arterial chemoembolization for primary hepatic carcinoma

OBJECTIVE

To explore the efficiency of single application of lobaplatin in tran-scatheter arterial chemoembolization (TACE) for patients with a primary hepatic carcinoma who were unable or unwilling to undergo surgery.

METHODS

173 patients with primary hepatic carcinoma diagnosed by imaging or pathology were randomly divided into experimental and control groups and respectively treated with lobaplatin and pirarubicin hydrochloride as chemotherapeutic drugs for TACE. The amount of iodipin was regulated according to the tumor number and size, and then gelatin sponge or polyvinyl alcohol particles were applied for embolisms. The efficiency of treatment in the two groups was compared with reference to survival time and therapeutic response.

RESULTS

The experimental group (single lobaplatin as chemotherapy drug) was superior to control group (single pirarubicin hydrochloride as chemotherapy drug) in the aspects of survival time and therapeutic response, with statistical significance.

CONCLUSIONS

Single lobaplatin can be as a chemotherapy drug in TACE and has better efficiency in the aspects of mean survival time and therapeutic response, deserving to be popularized in the clinic.

Chloroquine and hydroxychloroquine for cancer therapy

Macroautophagy (herein referred to as autophagy) is a highly conserved mechanism for the lysosomal degradation of cytoplasmic components. Autophagy is critical for the maintenance of intracellular homeostasis, both in baseline conditions and in the context of adaptive responses to stress. In line with this notion, defects in the autophagic machinery have been etiologically associated with various human disorders including infectious, inflammatory and neoplastic conditions. Once tumors are established, however, autophagy sustains the survival of malignant cells, hence representing an appealing target for the design of novel anticancer regimens. Accordingly, inhibitors of autophagy including chloroquine and hydroxychloroquine have been shown to mediate substantial antineoplastic effects in preclinical models, especially when combined with chemo- or radiotherapeutic interventions. The pharmacological profile of chloroquine and hydroxychloroquine, however, appear to involve mechanisms other than autophagy inhibition. Here, we discuss the dual role of autophagy in oncogenesis and tumor progression, and summarize the results or design of clinical studies recently completed or initiated to evaluate the therapeutic activity of chloroquine derivatives in cancer patients.

Repositioning metformin in cancer: genetics, drug targets, and new ways of delivery

After sitting many years on the shelves of drug stores as a harmless antidiabetic drug, metformin comes back in the spotlight of the scientific community as a surprisingly effective antineoplastic drug. Metformin targets multiple pathways that play pivotal roles in cancer progression, impacting various cellular processes, such as proliferation, cell death, metabolism, and even the cancer stemness features. The biomolecular characteristics of tumors, such as appropriate expression of organic cation transporters or genetic alterations including p53, K-ras, LKB1, and PI3K may impact metformin's anticancer efficiency. This could indicate a need for tumor genetic profiling in order to identify patients most likely to benefit from metformin treatment. Considering that the majority of experimental models suggest that higher, supra-clinical doses of metformin should be used in order to obtain an antineoplastic effect, new ways of drug delivery could be developed, such as metformin-loaded nanoparticles or incorporation of metformin into microparticles used in transarterial chemoembolization, with the aim of obtaining higher intratumoral drug concentrations and a targeted therapy which will ultimately maximize metformin's efficacy.

Towards stratifying ischemic components by cardiac MRI and multifunctional stainings in a rabbit model of myocardial infarction

OBJECTIVES

We sought to identify critical components of myocardial infarction (MI) including area at risk (AAR), MI-core and salvageable zone (SZ) by using cardiac magnetic resonance imaging (cMRI) and multifunctional stainings in rabbits.

MATERIALS AND METHODS

Fifteen rabbits received 90-min coronary artery (CA) ligation and reopening to induce reperfused MI. First-pass perfusion weighted imaging (PWI(90')) was performed immediately before CA reperfusion. Necrosis avid dye Evans blue (EB) was intravenously injected for later MI-core detection. One-day later, cMRI with T2-weighted imaging (T2WI), PWI(24h) and delayed enhancement (DE) T1WI was performed at a 3.0T clinical scanner. The heart was excised and CA was re-ligated with aorta infused by red-iodized-oil (RIO). The heart was sliced into 3-mm sections for digital radiography (DR), histology and planimetry with myocardial salvage index (MSI) and perfusion density rate (PDR) calculated.

RESULTS

There was no significant difference between MI-cores defined by DE-T1WI and EB-staining (31.13±8.55% vs 29.80±7.97%; p=0.74). The AAR was defined similarly by PWI90' (39.93±9.51%), RIO (38.82±14.41%) and DR (38.17±15.98%), underestimated by PWI(24h) (36.44±5.31%), but overestimated (p<0.01) by T2WI (56.93±8.87%). Corresponding MSI turned out to be 24.17±9.5% (PWI(90')), 21.97±9.41% (DR) and 22.68±9.65% (RIO), which were significantly (p<0.01) higher and lower than that with PWI(24h) (15.15±7.34%) and T2WI (45.52±7.5%) respectively. The PDR differed significantly (p<0.001) between normal myocardium (350.6±33.1%) and the AAR (31.2±15%), suggesting 11-times greater blood perfusion in normal myocardium over the AAR.

CONCLUSION

The introduced rabbit platform and new staining techniques together with the use of a 3.0T clinical scanner for cMRI enabled visualization of MI components and may contribute to translational cardiac imaging research for improved theranostic management of ischemic heart disease.