male or female and at least 18 years-of-age histologically confirmed diagnosis of myelofibrosis with myeloid metaplasia (MMM). This includes patients with agnogenic myeloid metaplasia (also known as idiopathic myelofibrosis) and patients with a preceding history of polycythemia vera or essential thrombocytemia (also known as post-polycytemic myelofibrosis). (see Appendix A) patients with low, intermediate and high risk disease categories (following the Dupriez score) may be included presence of measurable, clinically relevant disease manifestations (especially for low risk patients) ECOG performance status of 0, 1 or 2 life expectancy of at least 3 months Women of childbearing potential must use a medically acceptable form of contraception during the study and must have a negative urine or serum pregnancy test within 7 days of randomization written informed consent