Mapping Drug Dose Distribution on CT Images Following Transarterial Chemoembolization with Radiopaque Drug-Eluting Beads in a Rabbit Tumor Model

Effects of HepaSphere microsphere encapsule epirubicin with a new loading method transarterial chemoembolization: in vitro and in vivo experiments

METHODS

HS microspheres were loaded in a solution of hypertonic saline and contrast medium at different ratios. Morphology, size distribution, and drug loading capacity of the microsphere were evaluated. Rabbits with hepatic VX2 tumors underwent conventional TACE, drug-eluting beads TACE with HS microsphere loading epirubicin by recommended method (dTACE) or a new loading method (ndTACE). The plasma and tissue epirubicin concentration, tumor necrosis, and the microsphere distribution within the tumor were assessed.

RESULTS

It was found that the mean diameter of HS microspheres was effectively reduced to 102 ± 14 μm after loading with 10.0% NaCl and Ultravist (370 mg I /mL) at a ratio of 2: 8 ml. The loading capacity reached 78.7%. It was noted that the concentration of tumor epirubicin was significantly higher (p = 0.016) in the ndTACE group (11,989.8 ± 5776.6 ng/g) than the concentration in the dTACE (6516.5 ± 3682.3 ng/g) and in cTACE groups (1564.1 ± 696.1 ng/g, p < 0.001). Further, the tumor necrosis in group with the new loading method (ndTACE) was 92.4%.

CONCLUSIONS

The size of HS microsphere can be effectively reduced when it is loaded with a mixture of hypertonic saline and non-ionic contrast material. HS microsphere loaded with epirubicin using the new method (ndTACE) can increase the drug concentration in tumor and hence exert better improved antitumor effect.

Hydrogel drug delivery systems for minimally invasive local immunotherapy of cancer

Although systemic immunotherapy has achieved durable responses and improved survival for certain patients and cancer types, low response rates and immune system-related systemic toxicities limit its overall impact. Intratumoral (intralesional) delivery of immunotherapy is a promising technique to combat mechanisms of tumor immune suppression within the tumor microenvironment and reduce systemic drug exposure and associated side effects. However, intratumoral injections are prone to variable tumor drug distribution and leakage into surrounding tissues, which can compromise efficacy and contribute to toxicity. Controlled release drug delivery systems such as in situ-forming hydrogels are promising vehicles for addressing these challenges by providing improved spatio-temporal control of locally administered immunotherapies with the goal of promoting systemic tumor-specific immune responses and abscopal effects. In this review we will discuss concepts, applications, and challenges in local delivery of immunotherapy using controlled release drug delivery systems with a focus on intratumorally injected hydrogel-based drug carriers.

A 3D Tumor-Mimicking In Vitro Drug Release Model of Locoregional Chemoembolization Using Deep Learning-Based Quantitative Analyses

Primary liver cancer, with the predominant form as hepatocellular carcinoma (HCC), remains a worldwide health problem due to its aggressive and lethal nature. Transarterial chemoembolization, the first-line treatment option of unresectable HCC that employs drug-loaded embolic agents to occlude tumor-feeding arteries and concomitantly delivers chemotherapeutic drugs into the tumor, is still under fierce debate in terms of the treatment parameters. The models that can produce in-depth knowledge of the overall intratumoral drug release behavior are lacking. This study engineers a 3D tumor-mimicking drug release model, which successfully overcomes the substantial limitations of conventional in vitro models through utilizing decellularized liver organ as a drug-testing platform that uniquely incorporates three key features, i.e., complex vasculature systems, drug-diffusible electronegative extracellular matrix, and controlled drug depletion. This drug release model combining with deep learning-based computational analyses for the first time permits quantitative evaluation of all important parameters associated with locoregional drug release, including endovascular embolization distribution, intravascular drug retention, and extravascular drug diffusion, and establishes long-term in vitro-in vivo correlations with in-human results up to 80 d. This model offers a versatile platform incorporating both tumor-specific drug diffusion and elimination settings for quantitative evaluation of spatiotemporal drug release kinetics within solid tumors.

Engineering orthotopic tumor spheroids with organ-specific vasculatures for local chemoembolization evaluation

Developing a three-dimensional (3D) in vitro tumor model with vasculature systems suitable for testing endovascular interventional therapies remains a challenge. Here we develop an orthotopic liver tumor spheroid model that captures the organ-level complexity of vasculature systems and the extracellular matrix to evaluate transcatheter arterial chemoembolization (TACE) treatment. The orthotopic tumor spheroids are derived by seeding HepG2 cell colonies with controlled size and location surrounding the portal triads in a decellularized rat liver matrix and are treated by clinically relevant drug-eluting beads embolized in a portal vein vasculature while maintaining dynamic physiological conditions with nutrient and oxygen supplies through the hepatic vein vasculature. The orthotopic tumor model exhibits strong drug retention inside the spheroids and embolization location-dependent cellular apoptosis responses in an analogous manner to in vivo conditions. Such a tumor spheroid model built in a decellularized scaffold containing organ-specific vasculatures, which closely resembles the unique tumor microenvironment, holds the promise to efficiently assess various diagnostic and therapeutic strategies for endovascular therapies.

Clinical outcomes of vinorelbine loading CalliSpheres beads in the treatment of previously treated advanced lung cancer with progressive refractory obstructive atelectasis

Background: Drug-eluting beads bronchial arterial chemoembolization (DEB-BACE) has been used in the treatment of locally advanced lung cancer and has the potential to improve outcomes and reduce recurrence. However, DEB-BACE shows a poor therapeutic effect in advanced lung cancer after failure of multiple therapies. This study assessed the effect of DEB-BACE in the treatment of progressive lung cancer with refractory obstructive atelectasis. Methods: Progressive advanced lung cancer patients with refractory obstructive atelectasis were voluntarily enrolled in this study after failure of multiple conventional therapies. Baseline information, DEB-BACE treatment process, and changes in clinical symptoms were recorded. The primary endpoints were the objective response rate (ORR) and improvement rate of dyspnea. The secondary endpoints were time-to-progression (TTP), overall survival (OS), and rate of pulmonary re-expansion. Treatment-related adverse events and serious adverse events were analyzed to assess the safety of DEB-BACE. The Cox regression model was performed to analyze the possible factors impacting prognosis of DEB-BACE. Results: DEB-BACE was successfully performed with CalliSpheres beads loaded with vinorelbine in the 20 enrolled patients. ORR and disease control rate were 80% and 85%, respectively, at the first follow-up (43.4 ± 15.26 days). The improvement rate of dyspnea was 85% and 80% at 1 week and 1 month (p < 0.0001, p < 0.0001), respectively. TTP was 41.25 ± 14.43 days and 89.55 ± 61.7 days before and after DEB-BACE, respectively; DEB-BACE delayed the progression of advanced lung cancer (p < 0.0001). OS was 238.03 ± 33.74 days (95% confidence interval: 171.9-304.16). The rate of pulmonary re-expansion was 80% at the first follow-up. The reasons for poor prognosis were tumor necrosis, longer disease duration, and pulmonary atelectasis duration (p = 0.012, p = 0.038, p = 0.029). Massive hemoptysis was observed in two cases, and one patient died of asphyxia caused by hemoptysis. Moderate hemoptysis occurred in one case. All three adverse events were considered as the result of the tumor cavity after DEB-BACE. Conclusion: DEB-BACE loaded with vinorelbine is a feasible option for progressive advanced lung cancer with obstructive atelectasis after failure of other treatments.

Gut microbiota changes and biological mechanism in hepatocellular carcinoma after transarterial chemoembolization treatment

Background and aims

Intestinal flora is closely associated with the occurrence and development of hepatocellular carcinoma (HCC). However, gut microbial changes and biological mechanisms in HCC after transarterial chemoembolization (TACE) treatment are rarely reported.

Methods

We evaluated changes in intestinal flora after TACE in rabbit HCC models and assessed the impact of these changes on the disease. Twenty-four rabbit VX2 HCC models were established and intestinal flora structures, intestinal barrier function, changes in blood lipopolysaccharide (LPS) levels, Toll-like receptor 4 (TLR4), Cyclooxygenase-2 (COX-2), and p-signal transducer and activator of transcription 3(p-STAT3) protein expression levels were studied after TACE treatment.

Results

Compared with healthy rabbits, the intestinal flora in HCC models exhibited structural changes; intestinal barrier function was decreased, and increased LPS levels entered the circulation. A short-term follow-up after TACE showed the procedure partially reversed the intestinal microflora disorder caused by the tumor: intestinal barrier and liver functions were improved, intestinal LPS levels in the blood were reduced, and liver metabolism toward LPS was enhanced. Correlation analyses of the first 75 significantly changed bacteria with clinical factors showed that harmful bacteria had decreased and beneficial bacteria increased. Blood LPS levels and downstream signaling molecule TLR4, COX-2, and p-STAT3 protein expression levels were reduced, which correlated with tumor drug resistance and invasion capabilities.

Conclusions

We first characterized gut microbiota changes and biological mechanisms in HCC after TACE treatment. Our data provide a theoretical research basis for TACE combined with an intestinal flora intervention and systemic chemotherapy.

Clinical outcomes of gemcitabine-loaded callispheres drug-eluting beads for patients with advanced and inoperable lung cancer: A case series study

Aim: Drug-eluting beads transarterial chemoembolization (DEB-TACE) has not been widely used in patients with advanced and inoperable lung cancer. We aimed to report the preliminary outcomes of DEB-TACE with gemcitabine-loaded CalliSpheres beads for patients with advanced and inoperable lung cancer.

Methods: From November 2017 to October 2021, 37 patients (29 males, mean age 64.7 ± 10.3 years) with advanced and inoperable lung cancer underwent DEB-TACE with gemcitabine-loaded CalliSpheres beads. The primary endpoint was overall response rate, and the secondary endpoints were overall survival and progression-free survival.

Results: A total of 54 sessions of DEB-TACE were performed in 37 patients, with a technique success rate of 100%. Fourteen patients received a second session of DEB-TACE. The mean follow-up time was 18.7 ± 11.9 months. After 1, 3, and 6 months, overall response rate and disease control rate were 27.8% and 91.7%, 25.8% and 74.2%, 32.1%, and 67.9%, respectively. The median progression-free survival was 8.8 months (95% CI 7.5, 12.5 months). The 3-, 6- and 12- month progression-free survival rates were 67.1%, 57.0%, and 30.1%, respectively. The median overall survival was 10.0 months (95% CI 4.5, 13.1 months). The 3-, 6-, and 12- month overall survival rates were 88.5%, 72.7%, and 40.9%, respectively. Minor complications were observed in 14 patients (37.8%), with no procedure-related deaths or severe adverse events.

Conclusion: DEB-TACE with gemcitabine-loaded CalliSpheres beads is a safe, feasible and effective treatment strategy for patients with advanced and inoperable lung cancer.

Embolization therapy with microspheres for the treatment of liver cancer: State-of-the-art of clinical translation

Embolization with microspheres is a therapeutic strategy based on the selective occlusion of the blood vessels feeding a tumor. This procedure is intraarterially performed in the clinical setting for the treatment of liver cancer. The practice has evolved over the last decade through the incorporation of drug loading ability, biodegradability and imageability with the subsequent added functionality for the physicians and improved clinical outcomes for the patients. This review highlights the evolution of the embolization systems developed through the analysis of the marketed embolic microspheres for the treatment of malignant hepatocellular carcinoma, namely the most predominant form of liver cancer. Embolic microspheres for the distinct modalities of embolization (i.e., bland embolization, chemoembolization and radioembolization) are here comprehensively compiled with emphasis on material characteristics and their impact on microsphere performance. Moreover, the future application of the embolics under clinical investigation is discussed along with the scientific and regulatory challenges ahead in the field. STATEMENT OF SIGNIFICANCE: Embolization therapy with microspheres is currently used in the clinical setting for the treatment of most liver cancer conditions. The progressive development of added functionalities on embolic microspheres (such as biodegradability, imageability or drug and radiopharmaceutical loading capability) provides further benefit to patients and widens the therapeutic armamentarium for physicians towards truly personalized therapies. Therefore, it is important to analyze the possibilities that advanced biomaterials offer in the field from a clinical translational perspective to outline the future trends in therapeutic embolization.

Transarterial chemoembolization of unresectable renal cell carcinoma with doxorubicin-loaded CalliSpheres drug-eluting beads

The safety and efficacy of drug-eluting beads transarterial chemoembolization (DEB-TACE) for unresectable renal cell carcinoma (RCC) still unknown. We aimed to assess the feasibility, safety and clinical efficacy of DEB-TACE with doxorubicin-loaded CalliSpheres beads (CB) in patients with unresectable RCC. Between 2016 and 2020, thirty-five patients with unresectable RCC underwent DEB-TACE with doxorubicin-loaded CB. The objective response rate (ORR) was the primary endpoint, and overall survival (OS) and progression-free survival (PFS) were the secondary endpoints. Fifteen-seven times of DEB-TACE were performed in 35 patients using doxorubicin-loaded (median 60 mg) CB. Fifteen patients underwent an additional session of DEB-TACE, with intervals of 1 to 1.5 months. Twenty-one patients underwent transarterial infusion with cisplatin or oxaliplatin before DEB-TACE. The median follow-up time was 9.0 months (Range 1.8–43.6 months). ORR and DCR were 47.1% and 94.1%, 29.0% and 87.1%, 23.1% and 84.6% respectively at 1-, 3-, and 6- months after DEB-TACE. The median PFS was 21.4 months, and the 3-, 6- and 12- month PFS rates were 84.7%, 73.7% and 62.3%, respectively. The median OS was 24.6 months, and the 3-, 6- and 12- month OS rates were 93.9%, 87.6% and 65.2%, respectively. There were no treatment-related deaths or severe adverse events of grade 3 or more. In conclusion, DEB-TACE with doxorubicin-loaded CB is a safe, feasible and effective palliative treatment option for patients with unresectable RCC.

Cone-Beam Computed Tomography-Based Spatial Prediction of Drug Dose After Transarterial Chemoembolization Using Radiopaque Drug-Eluting Beads in Woodchuck Hepatocellular Carcinoma

OBJECTIVES

The aims of this study were to develop a model to estimate drug dose delivered to tumors after transarterial chemoembolization (TACE) with radiopaque drug-eluting beads (DEBs) based on DEB density on cone-beam computed tomography (CT) and to evaluate drug penetration into tissue in a woodchuck hepatoma model.

MATERIALS AND METHODS

Transarterial chemoembolization was performed in woodchucks with hepatocellular carcinoma (N = 5) using DEBs (70-150 μm, LC Bead LUMI) loaded with doxorubicin. Livers were resected 45 minutes after embolization, immediately frozen, and cut using liver-specific, 3D-printed sectioning molds. Doxorubicin levels in tumor specimens were measured by high-performance liquid chromatography and correlated with DEB iodine content that was measured using prototype cone-beam CT-based embolization treatment planning software. Doxorubicin penetration into tissue surrounding DEBs was assessed by fluorescence microscopy of tumor sections. Fluorescence intensity was converted into doxorubicin concentration using calibration standards. Intensity-thresholded color heatmaps were generated representing extravascular drug penetration.

RESULTS

Consistent segmentation of DEBs on cone-beam CT was achieved using a semiautomated intensity thresholding method. A positive linear correlation (0.96) was found between DEB iodine content measured on cone-beam CT and the amount of doxorubicin measured in tumor specimens. Prediction of doxorubicin levels in tumor sections that were not included in model development was accurate, with a root-mean-square error of 0.08 mg of doxorubicin. Tumor penetration of eluted doxorubicin resulted in concentration gradients where drug content decreased with increasing distance from blood vessels containing DEBs. Drug penetration was greater for blood vessels containing DEB clusters compared with single DEB, with higher doxorubicin concentrations extending further away from the vessels.

CONCLUSIONS

Estimation of drug dose delivered during transarterial chemoembolization in a woodchuck hepatocellular carcinoma model was possible using DEB radiopacity on cone-beam CT as a surrogate marker. Doxorubicin penetration was greatest adjacent to vessels containing DEB clusters compared with single DEB. Intraprocedural estimation of the spatial distribution of drug dose within the tumor could enable real-time adjustments to DEB delivery, to maximize treatment coverage or identify regions of tumor at risk for undertreatment.

Pirarubicin-loaded CalliSpheres® drug-eluting beads for the treatment of patients with stage III-IV lung cancer

BACKGROUND

CalliSpheres® beads (CB) have been used recently for patients with hepatocellular carcinoma. However, the safety and effect of drug-eluting bead transarterial chemoembolization (DEB-TACE) in patients with stage III-IV lung cancer are still unknown.

PURPOSE

To evaluate the safety and efficacy of DEB-TACE with pirarubicin-loaded CB for the treatment of stage III-IV lung cancer.

MATERIAL AND METHODS

From July 2016 to April 2020, 29 patients with stage III-IV primary lung cancer underwent DEB-TACE with pirarubicin-loaded CB. The objective response rate (ORR) was the primary endpoint; the secondary endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

Twenty-nine patients received DEB-TACE with pirarubicin-loaded (median 60 mg) CB, with no severe adverse events or treatment-related deaths. After DEB-TACE, hemoptysis disappeared within 1-3 days in all patients, and the symptoms of cough or expectoration were significantly improved in 12 patients. ORR and disease control rate at one, three, and six months after DEB-TACE were 39.3% and 96.4%, 26.1% and 69.6%, and 29.4% and 58.8%, respectively. The median PFS was 6.3 months (range 1.1-30.1 months), and the three-, six-, and 12-month PFS rates were 70.2%, 50.1%, and 27.1%, respectively. The median OS was 10.2 months (range 1.1-44.6 months), and the three-, six, and 12-month OS rates were 87.9%, 68.6%, and 39.8%, respectively.

CONCLUSION

DEB-TACE with pirarubicin-loaded CB is safe, feasible, and well-tolerated for patients with stage III-IV lung cancer, and symptom control was a potential benefit of treatment.

Recent advances and applications of microspheres and nanoparticles in transarterial chemoembolization for hepatocellular carcinoma

Transarterial chemoembolization (TACE) is a recommended treatment for patients suffering from intermediate and advanced hepatocellular carcinoma (HCC). As compared to the conventional TACE, drug-eluting bead TACE demonstrates several advantages in terms of survival, treatment response, and adverse effects. The selection of embolic agents is critical to the success of TACE. Many studies have been performed on the modification of the structure, size, homogeneity, biocompatibility, and biodegradability of embolic agents. Continuing efforts are focused on efficient loading of versatile chemotherapeutics, controlled sizes for sufficient occlusion, real-time detection intra- and post-procedure, and multimodality imaging-guided precise treatment. Here, we summarize recent advances and applications of microspheres and nanoparticles in TACE for HCC. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Percutaneous liquid ablation agent for tumor treatment and drug delivery

Percutaneous locoregional therapies (LRTs), such as thermal ablation, are performed to limit the progression of hepatocellular carcinoma (HCC) and offer a bridge for patients waiting for liver transplantation. However, physiological challenges related to tumor location, size, and existence of multiple lesions as well as safety concerns related to potential thermal injury to adjacent tissues may preclude the use of thermal ablation or lead to its failure. Here, we showed a successful injection of an ionic liquid into tissue under image guidance, ablation of tumors in response to the injected ionic liquid, and persistence (28 days) of coinjected chemotherapy with the ionic liquid in the ablation zone. In a rat HCC model, the rabbit VX2 liver tumor model, and 12 human resected tumors, injection of the ionic liquid led to consistent tumor ablation. Combining the ionic liquid with the chemotherapy agent, doxorubicin, resulted in synergistic cytotoxicity when tested with cultured HCC cells and uniform drug distribution throughout the ablation zone when percutaneously injected into liver tumors in the rabbit liver tumor model. Because this ionic liquid preparation is simple to use, is efficacious, and has a low cost, we propose that this new LRT may bridge more patients to liver transplantation.

Clinical outcomes of doxorubicin-eluting CalliSpheres® beads-transarterial chemoembolization for unresectable or recurrent esophageal carcinoma

BACKGROUND

The clinical outcomes of drug-eluting beads transarterial chemoembolization (DEB-TACE) with doxorubicin-loaded CalliSpheres® beads for patients with unresectable or recurrent esophageal carcinoma have not been reported. The aim of this study is to study the clinical outcomes of DEB-TACE for patients with unresectable or recurrent esophageal carcinoma.

METHODS

This retrospective study enrolled 21 patients (15 men; mean age 68.7 ± 9.7; range 46-86 years) with unresectable or recurrent esophageal carcinoma received DEB-TACE between July 2017 and September 2020. Patient characteristic data, imaging findings, complications and DEB-TACE procedure were reviewed. The primary endpoints, disease control rate (DCR) and objective response rate (ORR), were calculated. The secondary endpoints were overall survival rate and progression-free survival (PFS).

RESULTS

Twenty-two sessions of DEB-TACE were performed in 21 patients. The technical success rate was 100%; without sever adverse events or procedure-related deaths. All patients received transarterial chemotherapy infusion with raltitrexed or oxaliplatin. The median follow-up period was 3.6 months (interquartile range, IQR 1.5-9.4 months). ORR and DCR were 42.9 and 85.7%, 28.6 and 71.4%, 20.0 and 40.0% respectively at 1-, 3-, and 6-months after DEB-TACE. The median PFS was 6.0 months, and the 3-, 6- and 12-month PFS rates were 68.2%, 45.5 and 0.0%, respectively. The median overall survival was 9.4 months, and the 3-, 6- and 12-month overall survival rates were 75.5%, 55.0 and 13.8%, respectively.

CONCLUSIONS

To our knowledge, this is the first study reports outcomes of DEB-TACE with doxorubicin-loaded CallSpheres bead treatment in the management of patients with unresectable or recurrent esophageal carcinoma. According to our results, this is a safe and feasible treatment modality that may be considered among the options for the treatment of these patients.

Drug-eluting embolic microspheres: State-of-the-art and emerging clinical applications

INTRODUCTION

Drug-eluting embolic (DEE) microspheres, or drug-eluting beads (DEB), delivered by transarterial chemoembolization (TACE) serve as a therapeutic embolic to stop blood flow to tumors and a drug delivery vehicle. New combinations of drugs and DEE microspheres may exploit the potential synergy between mechanisms of drug activity and local tissue responses generated by TACE to enhance the efficacy of this mainstay therapy.

AREAS COVERED

This review provides an overview of key drug delivery concepts related to DEE microspheres with a focus on recent technological developments and promising emerging clinical applications as well as speculation into the future.

EXPERT OPINION

TACE has been performed for nearly four decades by injecting chemotherapy drugs into the arterial supply of tumors while simultaneously cutting off their blood supply, trying to starve and kill cancer cells, with varying degrees of success. The practice has evolved over the decades but has yet to fulfill the promise of truly personalized therapies envisioned through rational selection of drugs and real-time multi-parametric image guidance to target tumor clonality or heterogeneity. Recent technologic and pharmacologic developments have opened the door for potentially groundbreaking advances in how TACE with DEE microspheres is performed with the goal of achieving advancements that benefit patients.

Synthesis, characterization, and imaging of radiopaque bismuth beads for image-guided transarterial embolization

Current therapy for hypervascular cancers, e.g., hepatocellular carcinoma, includes occlusion of the tumor blood supply by arterial infusion of embolic microspheres (beads) suspended in iodine-based contrast under fluoroscopic guidance. Available radiopaque, imageable beads use iodine as the radiopacifier and cannot be differentiated from contrast. This study aimed to synthesize and characterize imageable beads using bismuth as the radiopacifier that could be distinguished from iodine contrast based upon the difference in the binding energy of k-shell electrons (k-edge). Radiodense bismuth beads were successfully synthesized some with uniform bismuth distribution across the beads. The beads were spherical and could be infused through clinical microcatheters. The bismuth beads could be imaged with clinical dual-energy computed tomography (CT), where iodine-based contrast could be distinguished from the microspheres. The ability to separate iodine from bismuth may enhance the diagnostic information acquired on follow-up CT, identifying the distribution of the embolic beads separately from the contrast. Furthermore, with sequential use of iodine- and bismuth-based beads, the two radiopaque beads could be spatially distinguished on imaging, which may enable the development of dual drug delivery and dual tracking.

Polymer microparticles with a cavity designed for transarterial chemo-embolization with crystalline drug formulations

Transarterial chemo-embolization with drug-eluting embolic beads (DEB-TACE) is still evolving. Recent developments include the introduction of radiopaque (X-ray imageable) drug-eluting particles. Here, we report on conceptually different radiopaque polymeric drug-eluting embolic particles, which are (i), cross-linked poly(methacrylates); (ii), radiopaque; (iii), microporous. Furthermore, the particles are not perfectly spherical: they have a large indentation in the sense that they are either a spherical/cup-shaped or ellipsoid/mouth-shaped. The micropores and the large indentation can confer useful features upon the particles, since they can be filled with a crystalline lipophilic chemotherapeutic drug. It is important, in this respect that (i), many potent chemotherapeutics are lipophilic and crystalline; (ii), available drug-eluting beads (DEBs) have the limitation that they can only be used in combination with water-soluble chemotherapeutic agents. Cup- and mouth-shaped particles were obtained in a Cu(0) catalyzed free-radical polymerization reaction. The microparticles could be charged with crystalline drug, in such a manner that the crystals reside in both the micropores and the large cavity, and in quantities that would be required for effective local chemotherapy. The antifungal drug voriconazole, lipophilic, and crystalline, was used to demonstrate this. We believe that the ability of the microporous/cavitated DEBs to carry lipophilic chemotherapeutic drugs is especially important. DEB-TACE is likely to become a cornerstone method of interventional oncology in the years ahead, and the new embolic particles described herein hold the promise of becoming scope widening for the technique.

Safety and Tolerability of Topotecan-Eluting Radiopaque Microspheres for Hepatic Chemoembolization in a Rabbit Preclinical Model

PURPOSE

Topotecan is a camptothecin analogue with potential advantages over irinotecan for transarterial chemoembolization (TACE) of hepatic colorectal metastases including greater anti-neoplastic activity without enzymatic activation. The purpose of this study was to assess safety and tolerability of topotecan-loaded radiopaque microspheres (ROMTOP) administered by TACE in a rabbit model and to compare the in vitro elution of topotecan from microspheres to irinotecan.

MATERIALS AND METHODS

Topotecan was loaded into radiopaque microspheres (70-150 µm, DC Bead LUMI™, Biocompatibles UK Ltd-Boston Scientific Corporation) to the maximum capacity of 80 mg/mL of microspheres. Six healthy New Zealand White rabbits underwent hepatic TACE with ROMTOP under fluoroscopic guidance until angiographic stasis. Assessment of toxicities included regular liver function tests and complete blood counts until euthanasia 28 days post-TACE. In vitro topotecan elution from the microspheres was assessed using an open-loop flow-through system and compared to irinotecan.

RESULTS

The mean bead volume and topotecan dose delivered were 0.086 mL (0.076-0.105 mL) and 1.99 mg/kg (1.51-2.55 mg/kg), respectively. Aspartate aminotransferase and alanine aminotransferase were elevated post-embolization but resolved within 2 weeks. One rabbit died two days after TACE with pyloric duodenal perforation observed at necropsy, potentially due to non-target embolization. In vitro elution of topotecan from ROMTOP was complete in 10 h compared to 3 h for irinotecan-loaded microspheres.

CONCLUSION

Selective embolization with ROMTOP was tolerated at a dose of 2 mg/kg (24 mg/m²) in rabbits. In vitro topotecan elution from microspheres was more prolonged compared to irinotecan.

Advances in the treatment of hepatocellular carcinoma using drug-eluting beads

Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumor. Although radical surgery and liver transplantation are possible cures for the disease, most patients are beyond the optimum stage for radical treatment at the time of diagnosis. Transarterial chemoembolization (TACE) is the first choice of treatment for advanced HCC. Owing to the widespread use of conventional TACE (cTACE), the problems with this treatment cannot be ignored. Drug-eluting beads (DEBs), a new type of embolization material, appear to overcome the problems of cTACE, and they have other advantages such as synchronous controlled continuous drug release after chemotherapy and embolization and low blood concentrations after treatment. This review summarizes the recent advances in the use of DEB-TACE to treat HCC.

Drug-eluting beads bronchial arterial chemoembolization as a neoadjuvant treatment for squamous non-small cell lung cancer

Introduction: The treatment for locally advanced squamous non-small cell lung cancer is still challenging. Drug-eluting beads bronchial arterial chemoembolization (DEB-BACE) is a novel drug delivery and embolization system for lung cancer that has the potential to improve outcomes and reduce the incidence of adverse events (AEs). It is very rare to administer DEB-BACE as neoadjuvant therapy for lung cancer and achieve pathological complete response (pCR). Body: A 69-year-old male was hospitalized because of cough and hemoptysis caused by locally advanced squamous non-small cell lung cancer. According to his choice, he received DEB-BACE treatment without obvious AEs. After the DEB-BACE treatment, the pulmonary lesion was controlled and lobectomy was performed. Postoperative pathology showed pCR. The patient has recovered well. Conclusion: This was the first case of DEB-BACE as a neoadjuvant therapy and achieved pCR for lung cancer. DEB-BACE might be a new neoadjuvant therapy option for locally advanced non-small cell lung cancer, especially for squamous cell cancer.

Liver-specific 3D sectioning molds for correlating in vivo CT and MRI with tumor histopathology in woodchucks (Marmota monax)

Purpose

To evaluate the spatial registration and correlation of liver and tumor histopathology sections with corresponding in vivo CT and MRI using 3D, liver-specific cutting molds in a woodchuck (Marmota monax) hepatic tumor model.

Methods

Five woodchucks chronically infected with woodchuck hepatitis virus following inoculation at birth and with confirmed hepatic tumors were imaged by contrast enhanced CT or MRI. Virtual 3D liver or tumor models were generated by segmentation of in vivo CT or MR imaging. A specimen-specific cavity was created inside a block containing cutting slots aligned with an imaging plane using computer-aided design software, and the final cutting molds were fabricated using a 3D printer. Livers were resected two days after initial imaging, fixed with formalin or left unfixed, inserted into the 3D molds, and cut into parallel pieces by passing a sharp blade through the parallel slots in the mold. Histopathology sections were acquired and their spatial overlap with in vivo image slices was quantified using the Dice similarity coefficient (DSC).

Results

Imaging of the woodchucks revealed heterogeneous hepatic tumors of varying size, number, and location. Specimen-specific 3D molds provided accurate co-localization of histopathology of whole livers, liver lobes, and pedunculated tumors with in vivo CT and MR imaging, with or without tissue fixation. Visual inspection of histopathology sections and corresponding in vivo image slices revealed spatial registration of analogous pathologic features. The mean DSC for all specimens was 0.83+/-0.05.

Conclusion

Use of specimen-specific 3D molds for en bloc liver dissection provided strong spatial overlap and feature correspondence between in vivo image slices and histopathology sections.

Transcatheter Intra-Arterial Infusion Combined with Interventional Photothermal Therapy for the Treatment of Hepatocellular Carcinoma

Background

Photothermal therapy (PTT) has great potential application in the treatment of tumors. However, due to the low penetration of near-infrared light (NIR) and the low concentration of nanomaterials in the tumor site, the application of PTT has been limited.

Purpose

The objective of this study was to investigate the therapeutic effect of transcatheter intra-arterial infusion of lecithin-modified Bi nanoparticles (Bi-Ln NPs) combined with interventional PTT (IPTT) on hepatocellular carcinoma.

Methods

Bi-Ln NPs were prepared by emulsifying the hydrophobic Bi nanoparticles and lecithin, and the photothermal conversion and cytotoxicity of Bi-Ln NPs were then measured by infrared imaging and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, respectively. Twenty-four VX2 hepatic carcinoma rabbits were randomly divided into four groups. Rabbits in group A received Bi-Ln NPs by intra-arterial infusion and NIR laser treatment (IA Bi-Ln NPs + Laser), group B received Bi-Ln NPs by intravenous infusion and NIR laser treatment (IV Bi-Ln NPs + Laser), group C received PBS (phosphate buffer saline) via intra-arterial infusion with NIR laser treatment (IA PBS + Laser), group D received PBS via intra-arterial infusion (IA PBS). Transcatheter intra-arterial infusion was conducted by superselective intubation under digital subtraction angiography (DSA) guidance. IPTT was performed by introducing an NIR optical fiber access to the rabbit VX2 hepatic carcinoma under real-time ultrasound guidance. Magnetic resonance imaging (MRI) was performed to evaluate the tumor size. Hematoxylin and eosin (H&E) stain and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were conducted 7 days after treatment to evaluate the necrosis rate and viability of tumor, respectively.

Results

The Bi-Ln NPs have the advantages of good biological compatibility and high photothermal conversion efficiency. Minimally invasive transcatheter intra-arterial infusion can markedly increase the concentration of Bi-Ln NPs in tumor tissues. IPTT can contribute to the significant improvement in the photothermal efficiency of Bi-Ln NPs. Compared to other groups, the group of IA Bi-Ln NPs + Laser showed a significantly higher tumor inhibition rate (TIR) of 93.38 ± 19.57%, a higher tumor necrosis rate of 83.12 ± 8.02%, and a higher apoptosis rate of (43.26 ± 10.65%) after treatment.

Conclusion

Transcatheter intra-arterial infusion combined with interventional PTT (IPTT) is safe and effective in eradicating tumor cells and inhibiting tumor growth and may provide a novel and valuable choice for the treatment of hepatocellular carcinoma in the future.

Transarterial Chemoembolization in a Woodchuck Model of Hepatocellular Carcinoma

PURPOSE

To assess the feasibility of transarterial chemoembolization with drug-eluting embolic (DEE) microspheres in a woodchuck model of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Nine woodchucks were studied: 4 normal animals and 5 animals infected with woodchuck hepatitis virus in which HCC had developed. Three animals with HCC underwent multidetector CT. A 3-F sheath was introduced into the femoral artery, and the hepatic arteries were selectively catheterized with 2.0-2.4-F microcatheters. Normal animals underwent diagnostic angiography and bland embolization. Animals with HCC underwent DEE transarterial chemoembolization with 70-150-μm radiopaque microspheres loaded with 37.5 mg doxorubicin per milliliter. Cone-beam CT and multidetector CT were performed. Following euthanasia, explanted livers underwent micro-CT, histopathologic examination, and fluorescence imaging of doxorubicin.

RESULTS

The tumors were hypervascular and supplied by large-caliber tortuous vessels, with arteriovenous shunts present in 2 animals. There was heterogeneous enhancement on multidetector CT with areas of necrosis. Six tumors were identified. The most common location was the right medial lobe (n = 3). Mean tumor volume was 30.7 cm³ ± 12.3. DEE chemoembolization of tumors was achieved. Excluding the 2 animals with arteriovenous shunts, the mean volume of DEE microspheres injected was 0.49 mL ± 0.17. Fluorescence imaging showed diffusion of doxorubicin from the DEE microspheres into the tumor.

CONCLUSIONS

Woodchuck HCC shares imaging appearances and biologic characteristics with human HCC. Selective catheterization and DEE chemoembolization may similarly be performed. Woodchucks may be used to model interventional therapies and possibly characterize radiologic-pathologic correlations.

Spectral CT Imaging-Based Quantification of Iodized Oil Retention following Chemoembolization: Phantom and Animal Studies

PURPOSE

To evaluate accuracy of iodine quantification using spectral CT and the potential of quantitative iodized oil analysis as an imaging biomarker of chemoembolization.

MATERIALS AND METHODS

A phantom of an artificial liver with 6 artificial tumors containing different amounts of iodized oil (0-8 vol%) was scanned by spectral CT, and iodized oil density (mg/mL) and Hounsfield unit (HU) values were measured. In addition, VX2 hepatoma was induced in 23 rabbits. After chemoembolization using iodized oil chemoemulsion, the rabbits were scanned by spectral CT. The accumulation of iodized oil in the tumor was quantified in terms of iodized oil density and HUs, and the performances in predicting a pathologic complete response (CR) were evaluated by receiver operating characteristic curve analyses.

RESULTS

The mean difference between true iodine densities and spectral image-based measurements was 0.5 mg/mL. Mean HU values were highly correlated with mean iodine density (r² = 1.000, P < .001). In the animal study, a pathologic CR was observed in 17 of 23 rabbits (73.9%). The range of area under the curve values of iodine and HU measurements was 0.863-0.882. A tumoral iodine density of 3.57 mg/mL, which corresponds to 0.7 vol% iodized oil in the tumor, predicted a pathologic CR with a sensitivity of 70.6% and a specificity of 100.0%.

CONCLUSIONS

Spectral CT imaging has a potential to predict tumor responses after chemoembolization by quantitatively assessing iodized oil in targets.

The efficacy of drug-eluting beads bronchial arterial chemoembolization loaded with gemcitabine for treatment of non-small cell lung cancer

Background

Drug‐eluting beads bronchial arterial chemoembolization (DEB‐BACE) can embolize the tumor‐feeding artery and also be loaded with antitumor drugs, which can be released slowly into the local tumor environment. The effect of DEB‐BACE in patients with lung cancer remains unclear. We evaluated the efficacy and safety of DEB‐BACE with gemcitabine‐loaded CalliSpheres beads in patients with non‐small cell lung cancer (NSCLC).

Methods

From May 2017 to December 2018, six patients with NSCLC who were ineligible or refused to receive standard treatment underwent DEB‐BACE with gemcitabine‐loaded CalliSpheres beads. The primary endpoint was the objective response rate (ORR). The secondary endpoints were progression‐free survival (PFS), overall survival (OS), and quality of life. Safety was evaluated by the occurrences of adverse events and serious adverse events.

Results

All patients were treated with DEB‐BACE loaded with gemcitabine (800 mg) using CalliSpheres beads. Five patients also received transarterial infusion with nedaplatin (80–100 mg). Of the six patients, five underwent a second session of DEB‐BACE, with intervals of one month between the first and second session. The median follow‐up time was 16.5 months (7.0–23.0 months). ORR and disease control rate were 50.0% and 100.0%, 50.0% and 83.3%, 50.0% and 66.7% respectively at 2, 4, and 6 months after DEB‐BACE. One patient maintained a partial response and the other five had progressive disease, of whom two patients died and the other three remained alive receiving targeted therapy, radiotherapy, transarterial infusion or thermal ablation. The median PFS was 8.0 months (4–23 months), and the 6‐ and 12 month PFS rates were 66.7% and 16.7%, respectively. The median OS was 16.5 months (7–23 months), and the six and 12 month OS rates were 100.0% and 66.7%, respectively. Hemoptysis, cough and dyspnea disappeared after DEB‐BACE in four patients. Global quality of life, physical and emotional functioning were all significantly improved at two months (P < 0.05). There were no serious adverse events.

Conclusions

DEB‐BACE with gemcitabine‐loaded CalliSpheres beads is a feasible and well‐tolerated treatment for patients with NSCLC who are ineligible or refuse to receive standard treatment.

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.