Antitumor Efficacy of Paclitaxel Injection Concentrate for Nanodispersion in Patient-Derived Breast, Head and Neck,...

Paclitaxel Injection Concentrate for Injection (PICN) is a novel nanoparticle formulation designed to overcome the limitations associated with the administration of marketed Cremophor and albumin based (nab) paclitaxel formulations. This study compared the in vivo antitumor efficacy of PICN with that of solvent-based paclitaxel and nab-paclitaxel in a murine NMRI nu/nu athymic nude mouse model bearing various human tumor xenotransplants: head and neck cancer (HNXF 1838 and HNXF 1842), lung cancer xenografts (LXFA 1584), and breast cancer xenografts (MAXF 574 and MAXF 1384). PICN displayed good to excellent antitumor activity. Moreover, PICN inhibited tumor growth more than solvent based paclitaxel formulation when compared at comparable tolerated dose levels. The higher antitumor efficacy of PICN compared to paclitaxel at lower dose levels of half the maximum tolerated dose (1/2MTD) was significant (P < 0.05) in three of the tumor models, i.e. HNXF 1842, MAXF 574, and MAXF 1384. The higher efficacy of PICN compared to paclitaxel was also evident at the MTD, but somewhat less pronounced, and was significant (P < 0.05) in one tumor model (HNXF 1838). The antitumor activity of PICN was similar to that of nab-paclitaxel. However, in one tumor model (HNXF 1838) PICN 50 mg/kg (1/2 MTD) showed a slight benefit over the same dose of nab-paclitaxel. The nanoparticulate nature of PICN and nab-paclitaxel therefore seems to enhance tumor cell penetration compared to conventional paclitaxel, resulting in better antitumor efficacy.