We investigated the pace of development of 48 approved anticancer agents except for endocrine in Japan up to the end of 1984. Forty-six new anticancer agents on which phase I-II studies had been carried out in our department from 1963 to 1984 and 34 anticancer agents approved in the USA were also referred to. Forty-eight approved drugs consisted of 23 domestic and 25 imported types. It was shown that the ability to develop new anticancer agents in Japan had grown remarkably after around 1970. Fourteen new domestic anticancer agents had been approved after 1973, whereas only 8 imported ones had been approved in the same period. Although more anticancer agents were approved in Japan than in the USA, the marketing of some anticancer agents approved in Japan was discontinued because of the lack of sufficient efficacy on reevaluation study or reduced efficacy compared with newly developed anticancer agents. Anticancer agents approved in the USA had a tendency to be used all over the world and for a long period. Many new domestic anticancer agents approved recently and which are under phase studies are derivatives of fluorinated pyrimidines, cytosine arabinoside and anthracyclines. The development of new domestic anticancer agents with an entirely new mode of action is therefore desirable.
