The present invention relates to conjugates of water-soluble polymers and o(chloracetyl-carbamoyl) fumagillol (TNP-470) and use of those conjugates as specific intracellular carriers of the TNP-470 into tumor vessels. The present invention further relates to use of those conjugates to lower the neurotoxicity of TNP-470. Preferably, the polymer has a molecular weight in the range of 100 Da to 800 kDa. More preferably, the polymer has a molecular weight no greater than 60 kDa. Most preferably, the polymer has a molecular weight in the range of 15 kDa to 40 kDa.