In Vivo Evaluation of Cisplatin-loaded Superabsorbent Polymer Microspheres for Use in Chemoembolization of VX2 Liver Tumors

Pickering-Emulsion for Liver Trans-Arterial Chemo-Embolization with Oxaliplatin

PURPOSE

Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticles can adsorb at the water/oil interface to stabilize the emulsion (forming Pickering-emulsion). The purpose of this study was to compare the release profiles of oxaliplatin from Pickering-emulsion and Lipiodol-emulsion.

MATERIALS/METHODS

Pickering-emulsions and Lipiodol-emulsions were both formulated with oxaliplatin (5 mg/mL) and Lipiodol (water/oil ratio: 1/3). For Pickering-emulsion only, PLGA nanoparticles (15 mg/mL) were dissolved into oxaliplatin before formulation. In vitro release of oxaliplatin from both emulsions was evaluated. Then, oxaliplatin was selectively injected into left hepatic arteries of 18 rabbits bearing VX2 liver tumors using either 0.5 mL Pickering-emulsion (n = 10) or 0.5 mL Lipiodol-emulsion (n = 8). In each group, half of the rabbits were killed at 1 h and half at 24 h. Mass spectrometry was used to quantify drug pharmacokinetics in blood and resulting tissue (tumors, right, and left livers) oxaliplatin concentrations.

RESULTS

Pickering-emulsion demonstrated a slow oxaliplatin release compared to Lipiodol-emulsion (1.5 ± 0.2 vs. 12.0 ± 6% at 1 h and 15.8 ± 3.0 vs. 85.3 ± 3.3% at 24 h) during in vitro comparison studies. For animal model studies, the plasmatic peak (C_max) and the area under the curve (AUC) were significantly lower with Pickering-emulsion compared to Lipiodol-emulsion (C_max = 0.49 ± 0.14 vs. 1.08 ± 0.41 ng/mL, p = 0.01 and AUC = 19.8 ± 5.9 vs. 31.8 ± 14.9, p = 0.03). This resulted in significantly lower oxaliplatin concentrations in tissues at 1 h with Pickering-emulsion but higher ratio between tumor and left liver at 24 h (43.4 vs. 14.5, p = 0.04).

CONCLUSION

Slow release of oxaliplatin from Pickering-emulsion results in a significant decrease in systemic drug exposure and higher ratio between tumor and left liver oxaliplatin concentration at 24 h.

Transcatheter Arterial Chemoembolization with Spherical Embolic Agent in Patients with Pulmonary or Mediastinal Metastases from Breast Cancer

PURPOSE

To evaluate safety and feasibility of transcatheter arterial chemoembolization with superabsorbent polymer microspheres (SAP-MS) for patients with pulmonary or mediastinal metastasis from breast cancer.

METHODS

Between November 2002 and January 2015, 14 patients with 29 unresectable pulmonary or mediastinal breast cancer metastases underwent transcatheter arterial chemoembolization using SAP-MS (50-100 μm) after injection of a combination of 2-4 types of anticancer drugs (eg, cisplatin [30 mg] + fluorouracil [500 mg], or epirubicin [40 mg] + mitomycin C [4 mg] + fluorouracil [500 mg]). As a primary endpoint, local tumor response and adverse events were evaluated 1 month after the first transcatheter arterial chemoembolization, according to Response Evaluation Criteria In Solid Tumors Version 1.1 and Common Terminology Criteria for Adverse Events Version 4 criteria. Transcatheter arterial chemoembolization was repeated as needed. Overall survival was analyzed as a secondary endpoint.

RESULTS

Response rate was 28.6% (partial response, 4 patients; stable disease, 10 patients). Median progression rate was -12.7%. No cases of hematologic toxicity of grade 3 or higher were observed. A grade 3 maculopapular rash was observed in 1 patient. After the first transcatheter arterial chemoembolization sessions, 63 additional transcatheter arterial chemoembolization sessions were performed (average, 5.5 sessions per patient; range, 2-10 sessions). The median overall survival time after the first session was 29 months, and the 5-year survival rate was 49.5%.

CONCLUSIONS

Transcatheter arterial chemoembolization with SAP-MS is a well-tolerated and feasible palliative treatment option for patients with pulmonary or mediastinal metastasis from breast cancer.