Patients are stratified according to the number of prior treatment regimens (0 or 1 vs more than 1). Patients receive irinotecan hydrochloride intravenously (IV) over 30 minutes followed immediately by cisplatin IV over 30 minutes followed 7 hours later by alvocidib IV over 1-4.5 hours weekly for 2 weeks. Courses repeat every 3 weeks in the absence of disease progression or unacceptable toxicity.