Dose-escalation stage (stage 1) The conventional 3+3 design (3 patients per dose cohort, with the potential to add additional 3 patients to the same cohort to further evaluate toxicity) will be applied for dose escalation and maximum tolerated dosage determination. Approximately 18 to 27 evaluable patients will be enrolled. The actual number of patients depends on the dose limited toxicities situation as well as the maximum tolerated dosage reached at this stage.