Reversible occlusion of the pulmonary vasculature by transarterial embolisation with degradable starch microspheres: preclinical assessment in a human isolated lung perfusion model

BACKGROUND

Transpulmonary embolisation (TPE) using degradable starch microspheres (DSM) is a potential approach to treat pulmonary metastases. However, there is a paucity of detailed information on perfusion dynamics. The aim of this study was to establish a human ex vivo isolated lung perfusion (ILP) model to observe and evaluate the effects of DSM-TPE in a near-physiologic setting.

METHODS

ILP was carried out on six surgically resected lung lobes. At baseline, computed tomography (CT), including CT perfusion imaging (CTPI), and histopathological sampling were performed (t30). DSM-TPE was initiated and increased stepwise (t45, t60, t75, and t90) to be followed by CT imaging, histopathological sampling, and pulmonary arterial pressure (PAP). After the last assessment (t90), alpha-amylase was injected into the pulmonary artery to allow for DSM hydrolysation and two additional assessments (t105; t120). Histopathological specimens were evaluated using a semiquantitative ordinal score. CTPI was used for time to peak (TTP) analysis.

RESULTS

After DSM administration, PAP and TTP increased significantly: PAP slope 95% confidence interval (CI) 0.104-0.483, p = 0.004; TTP t30 versus t45, p = 0.046. After the addition of alpha-amylase, functional parameters reverted to values comparable to baseline. In histopathological samples, embolisation grades increased significantly until t90 (slope 95% CI 0.027-0.066, p < 0.001) and decreased after addition of alpha-amylase (slope 95% CI -0.060-0.012, p = 0.165), CONCLUSIONS: The ILP model demonstrated successfully both the physiologic effect of DSM-TPE on human lungs and its reversibility with alpha-amylase. Thus, it can be used as a near-physiologic preclinical tool to simulate and assess later clinical approaches.

Measuring enzymatic degradation of degradable starch microspheres using confocal laser scanning microscopy

Degradable starch microspheres (DSM) have long been used for topical haemostasis, temporary vascular occlusion and as drug delivery systems. When used for the latter, exact degradation rates of DSM have high importance, as this ensures a controlled and timed drug delivery. Current methods of analysing degradation rates are based on whole batch measurements, which does not yield information regarding individual times of degradation nor does it provide direct correlation measurements between sphere diameter and specific degradation time. In this paper we present an alternative method for measuring degradation rates of biodegradable starch microspheres using confocal laser scanning microscopy (CLSM). We succeeded in visualizing the degradation by staining the DSM and then following the spheres over time in a confocal microscope, after the addition of α-amylase. Individual degradation rates of single spheres could be followed, allowing a precise correlation measure between sphere size and degradation time. Furthermore, physical abnormalities such as internal cavities were detected within some spheres. These physical differences also had a measurable effect on the rate of degradation. Finally, complete degradation rates could be determined very accurately. To our knowledge, this is the first paper in which DSM degradation is visualized and measured using CLSM. STATEMENT OF SIGNIFICANCE: Using degradable starch microspheres as a drug delivery system, is a continuously evolving field which shows promise in several different areas of illnesses. This paper presents a new method which visualizes enzymatic degradation of starch microspheres in real-time using confocal microscopy. The method is simple, yet the versatility of it suggests that it could be broadly applied within the field of biodegradation. Here, it illuminates a previously uninvestigated parameter: the effect of physical sphere deformities on the rate of degradation. It also provides precise correlation measures between initial sphere size and time of complete degradation.

Transarterial chemoembolization of colorectal cancer liver metastasis: improved tumor response by DSM-TACE versus conventional TACE, a prospective, randomized, single-center trial

OBJECTIVES

To prospectively evaluate the therapy response of third-line TACE with DSM or lipiodol in the treatment of CRLM using MRI.

METHODS

In this prospective, randomized, single-center trial, patients were randomly assigned to receive TACE therapy with either lipiodol or DSM as the embolization agent. Therapy response was evaluated using MRI. Local tumor response was determined according to RECIST 1.1, and survival data was analyzed using the Kaplan-Meier estimator.

RESULTS

Fifty patients (35 male, 15 female) were randomized and included in the survival analysis, whereas 31 patients completed therapy and were considered for evaluation of tumor responses (cTACE: n = 13, DSM-TACE: n = 18). In the cTACE group, PR was observed in 23%, SD in 15%, and PD in 62%. In the DSM-TACE-group, PR was observed in 22% of patients, SD in 56%, and PD in 22% (p = 0.047). In addition, the DSM-TACE group showed statistically significant tumor volume reduction (p = 0.006). Median apparent diffusion coefficient values were not significantly different between both groups at baseline (p = 0.26) and study endpoint (p = 0.83). Median survival in the cTACE group was 13 months (95% confidence interval, range 5-40 months) compared to 16 months (95% confidence interval, range 1-48 months) in the DSM-TACE group, exhibiting no statistically significant difference (p = 0.75).

CONCLUSION

DSM-TACE showed a significant difference reducing tumor volume and in tumor response according to RECIST 1.1 compared to cTACE. Thus, patients with CRLM might not only benefit from short embolization effect of DSM-TACE but also from better tumor responses. Apparent diffusion coefficients were not significantly different between both groups and cannot be used as a biomarker for monitoring for therapeutic effect of TACE.

KEY POINTS

• To our knowledge, this is the first prospective study that directly compared cTACE and DSM-TACE in patients with CRLM. • DSM-TACE showed a significant difference reducing tumor volume (p = 0.006) and in tumor response according to RECIST 1.1 (p = 0.047) compared to cTACE. • Survival analysis showed a median survival of 13 months in the cTACE group compared to 16 months in the DSM-TACE group (p = 0.75).

Transarterial Chemoembolisation (TACE) with Degradable Starch Microspheres (DSM) and Anthracycline in Patients with Locally Extensive Hepatocellular Carcinoma (HCC): Safety and Efficacy

PURPOSE

To evalutate safety and efficacy of degradable starch microspheres (DSM) as embolic agent in transarterial chemoembolisation (TACE) of unresectable, locally extensive hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In this retrospective study, 37 patients with intermediate to advanced HCC treated with ≥ 3 chemoembolisations with doxorubicin/epirubicin and DSM were analysed. Patients were treated with three consecutive chemoembolisations in 4-weekly intervals. Clinical parameters and laboratory findings were obtained from patient records before and after each intervention. Tumour response was assessed after every 3 embolisations by CT/MRI according to modified response evaluation criteria in solid tumours.

RESULTS

Thirty-seven patients with HCC were treated with 177 DSM-TACEs (3-12/patient, mean 4.8). Disease stages according to the Barcelona Clinic Liver Cancer (BCLC) staging system were: 27 × B, 9 × C, 1 × D. Five patients had uninodular, 32 multinodular (23 bilobar) disease. Three patients had portal vein invasion. Apart from one possibly procedure-related grade 3 complication, only grade 1 adverse events occurred. These were pain reacting to analgesics (23%), transient nausea (11%), vomiting (3%) and post-embolisation syndrome (4%). Transient laboratory changes were bone marrow toxicity (29%) and increase in INR (14%), creatinine (8%) or bilirubin (38%). Tumour response was objective response rate 49%, disease control rate 83%. Median survival was 19 months: 22 months for BCLC stage B and 6.7 months for BCLC stages C + D. Responders had a significantly better prognosis than non-responders.

CONCLUSION

DSM-TACE of HCC is safe even in patients with advanced disease stages. Tumour response and survival rates were encouraging in our series of patients with locally extensive disease.

Intra-arterial EmboCept S® and DC Bead® effectively inhibit tumor growth of colorectal rat liver metastases

BACKGROUND

Intra-arterial therapy with embolics is established for the treatment of malignancies of the liver. However, there are no studies comparing the different effects of various embolics used in clinical practice. Herein, we analyzed the effect of 3 different embolics on tumor growth in a rat model of colorectal liver metastases.

METHODS

Eight days after subcapsular implantation of 5 × 105 colorectal cancer cells (CC531) in the left liver lobe of WAG/Rij rats were randomized into 4 groups (n = 8) and underwent intra-arterial hepatic therapy. Animals received either EmboCept S®, DC Bead® or Lipiodol® Ultra-Fluid. Animals of the control group received a comparable amount of saline. Tumor growth was measured on day 8 and 11 using a three-dimensional 40 MHz ultrasound device. On day 11 tumor and liver tissue were removed for histological and immunohistochemical analyses.

RESULTS

On day 11 animals of the control group showed a tumor growth of ~ 60% compared to day 8. Application of Lipiodol Ultra-Fluid® did not significantly influence tumor growth (~ 40%). In contrast, treatment with EmboCept S® or DC Bead® completely inhibited tumor growth. Of interest, application of EmboCept S® did not only completely inhibit tumor growth but even decreased tumor size. Immunohistochemical analysis showed a significant increase of necrotic areas within the tumors after application of EmboCept S® and DC Bead® compared to Lipiodol® Ultra-Fluid.

CONCLUSION

The present study demonstrates that an intra-arterial therapy with EmboCept S® and DC Bead®, but not Lipiodol® Ultra-Fluid, results in a complete inhibition of rat colorectal liver metastatic growth.

Degradable starch microspheres transarterial chemoembolization (DSMs-TACE) in patients with unresectable hepatocellular carcinoma (HCC): long-term results from a single-center 137-patient cohort prospective study

PURPOSE

To evaluate safety and efficacy of degradable starch microspheres (DSMs) TACE in a large clinical cohort of patients with unresectable HCC.

MATERIALS AND METHODS

This is a single-center consecutive patients cohort study. The study was approved by local institutional ethics committee. Written informed consent was obtained. From December 2013 to March 2018, 137 cirrhotic patients with unresectable HCC were enrolled. For DSMs-TACE, a mixture of 4 mL of DSMs, 6 mL of non-ionic contrast and doxorubicin at a dose of 50 mg/m² were used. Primary end point was long-term outcome, in terms of time to progression (TTP) and overall survival (OS). Secondary endpoints were: safety, liver toxicity, 1-month percentage of tumor necrosis according to the modified RECIST criteria.

RESULTS

Two hundred and sixty-seven DSMs-TACE were performed in 137 HCC patients (33 patients in BCLC stage A, 84 patients in BCLC stage B, and 20 in stage C). Patients had a mean nodule number of 3.5 ± 1.2 (SD). Major complications were observed in 6.8% of cases. Post-embolization syndrome was common (101 patients 73.7%). According to mRecist criteria, a high objective response rate was obtained even after just one treatment (84.3% of patients showed complete response or partial response). The median TTP and OS after DSMs-TACE were 12 months and 36 months, respectively. OS at 6 months, 1 year, 2 and 3 years was 98%, 81.3%, 57.9%, 34.9%, respectively.

CONCLUSION

DSMs-TACE is a safe and effective therapy for patients with HCC, allowing to obtain a good rate of OS with excellent local tumor control.

Downstaging disease in patients with hepatocellular carcinoma outside up-to-seven criteria: Strategies using degradable starch microspheres transcatheter arterial chemo-embolization

AIM: To evaluate the downstaging rates in hepatitis C virus-patients with hepatocellular carcinoma (HCC), treated with degradable starch microspheres transcatheter arterial chemoembolization (DSM-TACE), to reach new-Milan-criteria (nMC) for transplantation.

METHODS: This study was approved by the Ethics Committee of our institution. From September 2013 to March 2014 eight patients (5 men and 3 women) with liver cirrhosis and multinodular HCC, that did not meet nMC at baseline, were enrolled in this study. Patients who received any other type of treatment such as termal ablation or percutaneous ethanol injection were excluded. DSM-TACE was performed in all patients using EmboCept^® S and doxorubicin. Baseline and follow-up computed tomography or magnetic resonance imaging was assessed measuring the longest enhancing axial dimension of each tumor according to the modified Response Evaluation Criteria In Solid Tumors measurements, and medical records were reviewed.

RESULTS: DSM-TACE was successfully performed in all patients without major complication. We treated 35 lesions (mean 4.3 per patient). Six of eight patients (75%) had their HCC downstaged to meet nMC. Every patient whose disease was downstaged eventually underwent transplantation. The six patients who received transplant were still living at the time of this writing, without recurrence of HCC. Baseline age (P = 0.25), Model for End-stage Liver Disease score (P = 0. 77), and α-fetoprotein level (P = 1.00) were similar between patients with and without downstaged HCC.

CONCLUSION: DSM-TACE represents a safely and effective treatment option with similar safety and efficacy of conventional chemoembolization and could be successfully performed also for downstaging disease in patients without nMC, allowing them to reach liver transplantation.