Indazolium trans-[tetrachlorobis(1H-indazole)ruthenate (III)]has been selected for clin. development from a large series of ruthenium(III) complexes with azole ligands coordinated to the metal center through nitrogen, mainly because of its superior efficacy in preclin. tumor models. KP1019 is capable of occupying the iron-binding sites of transferrins. In the model mol. lactoferrin (a close homolog of serum transferrin), it binds with a high affinity to His 253 in the specific N-lobe metal binding cleft. Furthermore, KP1019 is capable of being delivered to cells via the transferrin receptor-mediated endocytotic route. Up-regulation of transferrin receptors as a consequence of the high iron demand is commonly found in tumor cells, rendering them susceptible to the cytotoxic effects of KP1019. The redox activity and cytotoxicity, mode of action, and antitumor activity and toxicity in vivo of KP1019 are discussed. [on SciFinder (R)] ; CAN 145:116811 1-6 Pharmacology Institute of Inorganic Chemistry - Bioinorganic, Environmental and Radiochemistry,University of Vienna,Vienna,Austria. Journal 124875-20-3 (KP1019) Role: DMA (Drug mechanism of action), PAC (Pharmacological activity), THU (Therapeutic use), BIOL (Biological study), USES (Uses) (KP1019 is capable of occupying iron-binding sites of transferrin)