Current status of development of anticancer agents in Japan.

To investigate the current status of the development of anticancer agents in Japan, we examined the number of these agents developed after 1999, their target diseases, and the association between the number of approved agents and the number of patients with the diseases. The data were obtained via the Internet. Of the 487 agents approved from 1999 to April 2007, 84 were anticancer drugs. Of these 84, 46 were approved based on clinical trials and 38 were approved through the new drug application for off-label usages without clinical trials. The target diseases of the 46 agents approved through clinical trials were nonhematologic tumors in 29, hematologic malignancies in 13, and others in 4. Of the 38 approved through the new drug application for off-label usages, 31 were for nonhematologic tumors and 7 for hematologic malignancies. The number of approved anticancer agents for hematologic malignancies per unit patient population was 6.5-times as many as that for nonhematologic tumors. This study demonstrated that the situation regarding the development of anticancer agents differs among tumor types. The majority of anticancer agents developed target hematologic malignancies, while the newly developed anticancer agents have affected treatment strategies for solid tumors.