Abstract
Polymeric micelles were expected to increase the accumulation of drugs in tumor tissues utilizing the EPR effect and to incorporate various kinds of drugs into the inner core by chemical conjugation or physical entrapment with relatively high stability. The size of the micelles can be controlled within the diameter range of 20 to 100 nm, to ensure that the micelles do not pass through normal vessel walls; therefore, a reduced incidence of the side effects of the drugs may be expected. There are several anticancer agent-incorporated micelle carrier systems under clinical evaluation. NK105, paclitaxel (PTX) -incorporating micelle, facilitated prolonged systemic exposure in plasma in Japanese phase I study. Tri-weekly 1-hr infusion of NK105 was feasible and well tolerated, with antitumor activity. A phase II study of NK105 has been terminated. A phase I study of NC-6004, cisplatin (CDDP) -incorporating micelle was conducted in the UK. Nephrotoxicity was significantly reduced and gastrointestinal toxicity was also mild. Two independent phase I trials of NK012, an SN-38 loaded polymeric micelle, were conducted successfully in Japan and the USA. NK012 was well tolerated and phase II studies of NK012 are now underway in both countries.
