 I. To estimate the maximum tolerated dose MTD andor recommended Phase II dose of obatoclax obatoclax mesylate administered as a single agent on day 1 and in combination with vincristine vincristine sulfate, doxorubicin doxorubicin hydrochloride, and dexrazoxane dexrazoxane hydrochloride at day 8 in children with refractory solid tumors. 