1. Participant is:
a. Within the age range of 50 to 74 years OR
b. Less than 50 years of age, but at high risk for regimen-related toxicity using standard, high-dose regimens.
2. Participant has been diagnosed with CMML or has previously untreated MDS or MPD.
3. Participant has a matched, related donor or a matched, unrelated donor.
Other eligibility criteria may apply.
1. HIV-positive or other serious, active viral, bacterial or fungal infection.
2. Active central nervous system involvement with the disease.
3. Presence, or likely occurrence, of other non-hematologic, malignant disease according to study guidelines.
4. Pregnant or breastfeeding.
5. Severe heart, lung, kidney or liver disorder.
6. Medical or physical condition that may prevent the participant from completing the study.
Other exclusion criteria may apply.