Comparative study of the antitumor activity of Nab-paclitaxel and intraperitoneal solvent-based paclitaxel regarding peritoneal metastasis in gastric cancer.

Intraperitoneal (i.p.) chemotherapy with paclitaxel (PTX) has been shown to be a promising treatment strategy for peritoneal metastasis. The present study focused on the comparative evaluation of the therapeutic efficacy of nanoparticle albumin-bound PTX (Nab-PTX) and i.p. administration of the conventional solvent-based PTX (Sb-PTX). We also investigated the difference in antitumor activity depending on the route of administration in the Nab-PTX treatment. Nab-PTX was administered i.p. or intravenously (i.v.) and Sb-PTX was administered i.p. at equitoxic and equal doses to nude mice bearing gastric cancer OCUM-2MD3 cell subcutaneous and peritoneal xenografts. Therapeutic efficacy of Sb-PTX and Nab-PTX was evaluated as inhibition of tumor growth using a peritoneal metastatic model with subcutaneous xenografts. The survival rate was also investigated using mouse peritoneal models. For assessment of subcutaneous tumors, the change in tumor volume was measured, and for assessment of peritoneal tumors, the weight of ascitic fluid and the total peritoneal tumor burden were measured for each individual mouse. At equitoxic doses, treatment with Nab-PTX resulted in a greater reduction in the size of subcutaneous tumors and the weight of ascites and peritoneal burden as compared with i.p. Sb-PTX (p<0.05). Treatment with i.p. and i.v. Nab-PTX also achieved greater survival benefit than i.p. Sb-PTX (p<0.05). In contrast, there was no significant difference in the degree of tumor reduction and the survival time between both drugs at equal doses. With regard to the route of administration, the antitumor efficacy of Nab-PTX after i.v. administration was equivalent to the efficacy after i.p. administration. These results suggest that i.v. Nab-PTX may be another encouraging treatment option that can target peritoneal dissemination in gastric cancer.