- Has one of the following diagnoses: Subjects must have refractory or relapsed AML or ALL, CML in blast phase, or high risk MDS (defined by Revised International Prognostic Scoring System [IPSS-R] score as High or Very High for inclusion in Part 1 of the study. Subjects must have refractory or relapsed AML or high-risk MDS (defined by IPSS-R score as High or Very High for inclusion in Part 2 of the study.