Enhanced efficacy of anti-tumor liposomal doxorubicin by hyperthermia

Combination Treatment with Liposomal Doxorubicin and Inductive Moderate Hyperthermia for Sarcoma Saos-2 Cells

Despite efforts in osteosarcoma (OS) research, the role of inductive moderate hyperthermia (IMH) in delivering and enhancing the antitumor effect of liposomal doxorubicin formulations (LDOX) remains unresolved. This study investigated the effect of a combination treatment with LDOX and IMH on Saos-2 human OS cells. We compared cell viability using a trypan blue assay, apoptosis and reactive oxygen species (ROS) measured by flow cytometry and pro-apoptotic Bax protein expression examined by immunocytochemistry in response to IMH (42 MHz frequency, 15 W power for 30 min), LDOX (0.4 μg/mL), and LDOX plus IMH. The lower IC50 value of LDOX at 72 h indicated increased accumulation of the drug in the OS cells. LDOX plus IMH resulted in a 61% lower cell viability compared to no treatment. Moreover, IMH potentiated the LDOX action on the Saos-2 cells by promoting ROS production at temperatures of <42 °C. There was a 12% increase in cell populations undergoing early apoptosis with a less heterogeneous distribution of Bax after combination treatment compared to those treated with LDOX (p < 0.05). Therefore, we determined that IMH could enhance LDOX delivery and its antitumor effect via altered membrane permeabilization, ROS generation, and a lower level of visualized Bax heterogeneity in the Saos-2 cells, suggesting the potential translation of these findings into in vivo studies.

Phase I study of heat-deployed liposomal doxorubicin during radiofrequency ablation for hepatic malignancies

PURPOSE

A phase I dose escalation study was performed with systemically delivered lyso-thermosensitive liposomal doxorubicin (LTLD). The primary objectives were to determine the safe maximum tolerated dose (MTD), pharmacokinetic properties, and dose-limiting toxicity (DLT) of LTLD during this combination therapy.

MATERIALS AND METHODS

Subjects eligible for percutaneous or surgical radiofrequency (RF) ablation with primary (n = 9) or metastatic (n = 15) tumors of the liver, with four or fewer lesions as large as 7 cm in diameter, were included. RF ablation was initiated 15 minutes after starting a 30-minute intravenous LTLD infusion. Dose levels between 20 mg/m(2) and 60 mg/m(2) were evaluated. Magnetic resonance imaging, positron emission tomography, and computed tomography were performed at predetermined intervals before and after treatment until evidence of recurrence was seen, administration of additional antitumor treatment was performed, or a total of 3 years had elapsed.

RESULTS

DLT criteria were met at 60 mg/m(2), and the MTD was defined as 50 mg/m(2). RF ablation was performed during the peak of the plasma concentration-time curve in an effort to yield maximal drug deposition. LTLD produced reversible, dose-dependent neutropenia and leukopenia.

CONCLUSIONS

LTLD can be safely administered systemically at the MTD (50 mg/m(2)) in combination with RF ablation, with limited and manageable toxicity. Further evaluation of this agent combined with RF ablation is warranted to determine its role in the management of liver tumors.

Lyso-thermosensitive liposomal doxorubicin: a novel approach to enhance efficacy of thermal ablation of liver cancer

BACKGROUND

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer death worldwide. No more than 30% of HCC patients receive curative treatment. Factors limiting curative therapy include tumor size and degree of liver impairment.

OBJECTIVE

To develop a cure for medium (3.1-5.0 cm) and large (>5 cm) tumors in seriously impaired livers.

METHOD

Combine radiofrequency ablation (RFA) with lyso-thermosensitive liposomal doxorubicin (LTLD).

RESULTS/CONCLUSIONS

RFA is used safely in patients with medium/large tumors and severe liver impairment; unclear tumor margins limit its curative efficacy. LTLD concentrates in the liver, where the anti-HCC chemotherapeutic, doxorubicin, is released into tumor margins by hyperthermia. RFA/LTLD can treat Child-Pugh class A-B patients with tumors up to 7 cm, a substantial increase in curable patients.