Non-Platinum Antitumor Compounds

Non-platinum antitumor compounds have gained increasing interest during the last decade. A variety of antitumor active agents, from early transition to main-group metal or metalloid compounds, has been found and evaluated. Due to their different chemical characteristics, the mode of action and spectrum of activity of these compounds differ from each other. Antitumor activity in vitro is known for many compounds. Some compounds, like the ruthenium complexes, also exhibit promising in vivo activity. Two early transition metal complexes show interesting activity especially in experimental colon tumor models and are under evaluation in clinical trials: titanocene dichloride and budotitane. The two germanium complexes spirogermanium and germanium-132 have been evaluated but, despite their moderate toxicity, no encouraging results have been obtained. Gallium nitrate and gallium chloride are active against lymphomas and bladder cancer, and show a positive effect on hypocalcaemias caused by tumors. They have undergone a number of clinical trials and are being investigated in promising combination regimens. Arsenic trioxide was found to be active against a rare blood cancer in clinical studies in China.