An Ascending Dose Study of KW-2449 in Acute Leukemias, Myelodysplastic Syndromes, and Chronic Myelogenous Leukemia

This is a Phase I open-label dose escalation study of KW-2449 in subjects with acute leukemias, high risk MDS, and CML who are not candidates for approved therapy. Over an 18-month period, the investigative sites collectively will enroll up to a total of 96 subjects. Subjects will be enrolled sequentially into 1 of 7 dose groups to evaluate 2 dosing schedules (Arm A = 14 consecutive days of dosing followed by a 7-28 day rest period as determined by recovery from any acute hematologic and non-hematologic toxicities, or Arm B = 28 consecutive days of dosing followed by a 7-28 day rest period, as determined by recovery from any acute hematologic and non-hematologic toxicities). The safety of a dose level in Arm A (14-day dosing regimen) will be established prior to enrollment of subjects in the same dose level in Arm B (28-day dosing regimen). In April 2007 the protocol was amended to discontinue Arm B (28 consecutive days of dosing). The protocol will continue as planned for Arm A (14 days of consecutive dosing). Enrollment will proceed until a maximum tolerated dose (MTD) has been established for each study Arm. Once the MTD has been reached, 12 additional subjects, with 1 or more of the hematologic conditions included in this study, may be enrolled at the MTD as an expanded safety cohort.