Development and validation of sorafenib-eluting microspheres to enhance therapeutic efficacy of transcatheter arterial chemoembolization in a rat model of hepatocellular carcinoma

Abstract

Purpose: To validate the therapeutic efficacy of sorafenib-eluting embolic microspheres (SOR-EMs) used in combination with transar-terial chemoembolization (TACE) for treatment of hepatocellular carcinoma (HCC) in a preclinical animal model. Materials and Methods: SOR-EMs were prepared with poly(d,l-lactide-co-glycolide), iron oxide nanoparticles, and sorafenib. The mor-phology of the prepared SOR-EMs was confirmed by using optical microscopy. Drug release from the SOR-EMs was quantified in vi-tro by using high-performance liquid chromatography. In an orthotopic rat model of HCC, embolic doxorubicin–Lipiodol (ethiodized oil) emulsion (DLE) and SOR-EMs were sequentially injected into the hepatic artery of the rats: The rats in group 1 were injected with DLE; group 2 was injected with DLE plus unloaded embolic microspheres (DLE + EM); group 3, with DLE plus SOR-EMs (DLE + SOR-EM); and group 4, with saline solution. The SOR-EM and tumor size changes in each group (of six rats each) over time were measured by using MRI. Tissues were assessed by using immunohistochemistry, with hematoxylin-eosin and terminal deoxynucleotidyl transferase-mediated dUTP (2’-deoxyuridine 5’-triphosphate) nick-end labeling staining used for dead cells and CD34 staining used for new microvessel formation. Results: The SOR-EMs were a mean size of 6.6 μm ± 2.3 (standard deviation) and showed 53.7% ± 8.3 sorafenib loading efficiency with T2-weighted MRI capability. In the HCC rat model, the intra-arterially injected SOR-EMs were successfully monitored by using MRI. The DLE + SOR-EM–treated rats showed a superior tumor growth–inhibitory effect compared with the rats treated with DLE only (P < .05). Immunohistochemical assessment of tissue specimens showed that compared with the other treatment groups, the DLE + SOR-EM treatment group had the lowest number of microvessels, as quantified by using the percentage of CD34-positive stained area (P < .01 for all comparisons). Conclusion: In a preclinical rat HCC model, SOR-EMs used in combination with DLE TACE were effective in treating HCC.