The primary purpose of this study is to (1) determine the maximally tolerated dose (MTD) of L-377202 administered once every 3 weeks, (2) evaluate the safety and tolerability of L-377202 including the dose-limiting adverse effects of treatment with L-377202, and (3) assess the pharmacokinetics of various doses of L-377202 and the plasma profile of liberated doxorubicin and leu-doxorubicin.