Rasburicase Versus Allopurinol in Tumor Patients at Risk for Hyperuricemia and Tumor Lysis Syndrome

This is a randomized, multi-center, open-label, parallel group study with three arms: * Rasburicase alone * Rasburicase followed by Allopurinol * Allopurinol alone The primary objective is to compare the adequacy of control of plasma uric acid concentration and the safety profile among the three arms.