Evaluation of a new drug 7-N-(p-hydroxyphenyl)-mitomycin C [KW 2083] against carcinoma of the lung by the human tumor clonogenic assay.

KW 2083, which is a new mitomycin C derivative currently under clinical investigation, was tested for its antitumor effect on the growth of human carcinoma of the lung by using an in vitro clonogenic assay system. The in vitro results in this study were as follows: We succeeded in producing clonal growth at a high rate in all histologic types of carcinoma of the lung in the assay system. That is, 61 of 81 specimens (75%) of either primary or metastatic tumors gave adequate growth for chemosensitivity testing. The in vitro responses to vindesine, adriamycin, mitomycin C and melphalan (substituted for cyclophosphamide in vitro), as standard anticancer drugs for chemotherapy of carcinoma of the lung were 18, 23, 18 and 19%, respectively, which are in good general agreement with the clinical responses to these drugs reported previously. Therefore, the clonogenic assay system might prove to be a very effective tool for an in vitro phase II study of new drugs. The rate of response to KW 2083 tested simultaneously in 51 cancer specimens was 22%, which was superior to that of mitomycin C. These results indicate that KW 2083 might be more useful than mitomycin C in clinical practice.