Reduction of tumour blood flow with KB-R8498 potentiates the response of tumours to hyperthermia

The anti-tumour activity and the effect on tumour and normal tissue perfusi on of a newly discovered anticancer agent, KB-R8498 (Kanebo Ltd., Osaka, Ja pan), were investigated in FSa II tumours of C3H mice. The tumour perfusion , as measured by the Rb-86-uptake method, markedly decreased with relativel y little change in the normal tissue perfusion after an i.v. injection of K B-R8498. Furthermore, the drug potentiated the effect of hyperthermia at 42 .5 degrees C for 60 min to suppress the tumour growth. The results suggest that the preferential reduction in tumour blood flow relative to normal tis sue blood flow by KB-R8498 may be exploited to enhance the anti-tumour effe ct of hyperthermia.