Inclusion Criteria

Inclusion Criteria

- Patients aged 18 to 65 years, inclusive

- Patients must have a hematological malignancy that as per standard medical practice
requires myeloablative conditioning (including short term myeloablative reduced
intensity conditioning) followed by allogeneic hematopoetic stem cell transplant

- Karnofsky Performance status ≥60%.

- Suitable stem cell source available according to the graft selection algorithm
using T-cell replete peripheral stem cells as a graft source

Exclusion Criteria:

- Resting heart rate below 55

- Significant cardiac disease (such as arrhytmia, heart failure) or any significant
condition which in the investigators opinion would make the patient ineligible

- Previous allogeneic HSCT

- Any drug required that is not compatible with KRP203 (e.g. beta-blockers or
anti-thymocyte globulin)