[Antitumor effect of a benzoylphenylurea derivative HO-221].

: HO-221, N-[4-(5-Bromo-2-pyrimidinyloxy)-3-chlorophenyl]-N'-(2-nitrobenzoyl ) urea is a novel benzoylphenylurea derivative. We had interested in various pharmacological actions of benzoylphenylurea compounds. Therefore, many compounds were synthetized and tested in various screening systems. In the process with these tests, we found HO-221 which showed an excellent antitumor activity. The antitumor activity of HO-221 was judged from the survival time and the tumor weight of experimented tumor-bearing animals. HO-221 preparation was orally administered. The compound exhibited significant effects against various animal tumors (P388, L1210, M5076, LLC, C38, S180, W256), and especially effective against the solid tumors. HO-221 was also markedly effective to MX-1 and LX-1 implanted into nude mice. However, the effect against mouse B16 melanoma was moderate. In addition, HO-221 showed a schedule dependency and once every 4 or 7 days treatments were most effective. The antitumor activities of the compound against advanced L1210 and Lewis lung tumors were examined. Tegafur and ara-C were used as reference drug for the study. Three agents showed the antitumor activities against L1210. Against Lewis lung carcinoma, HO-221 showed both the increase of life span and the tumor growth inhibition. On the other hand, tegafur and ara-C were ineffective for the increase of life span.