Therapeutic efficacy of 188Re-liposome compared with 5-FU in CT26-luc lung-metastatic mice model via intravenous route

Objectives The aim of this study was to investigate the therapeutic efficacy of intravenously administrated 188Re-liposome compared with 5-FU in the CT26-luc lung-metastatic model.

Methods These studies were performed on mice at 17 d after tumor inoculation. The comparative efficacy of 188Re-liposome and 5-FU was performed by a single-dose treatment in lung-metastatic tumor-bearing mice. Mice were checked for survival every day until death. The body weight was measured twice a week.

Results In efficacy study, the median survival time for the mice (n = 8), which received normal saline was 34.7 d. The median survival times for the mice treated with 80%MTD (29.6 MBq, n = 7) and 60%MTD (22.2 MBq, n = 8) of 188Re-liposome were 59.8 d (P = 0.001) and 48.3 d (P = 0.003), respectively. The median survival times for the mice treated with 80%MTD (144 mg/kg, n = 7) and 60%MTD (108 mg/kg, n = 8) of 5-FU were 52.5 d (P = 0.002) and 38.0 d (P = 0.580), respectively. The increase in life span of 80%MTD and 60%MTD of 188Re-liposome were 72.3%, and 39.4%, respectively. The increase in life span of 80%MTD and 60%MTD of 5-FU were 51.4%, and 9.6%, respectively.

Conclusions The therapeutic studies of 188Re-liposome demonstrated better survival time and therapeutic efficacy for mice compared with the same MTD of 5-FU in CT26-luc lung-metastatic mice model. These results suggested that intravenous administration of 188Re-liposome could provide a benefit and promising strategy for delivery of passive nanotargeted radiotherapeutics in oncology applications.