1. Patients > = 18 years with a documented history of myelofibrosis transformed to acute myeloid leukemia using the World Health Organization criteria of > = 20% blasts in the peripheral blood or bone marrow; the diagnosis of myelofibrosis could be either primary myelofibrosis (myelofibrosis with myeloid metaplasia, agnogenic myeloid metaplasia), post-polycythemia vera or post-essential thrombocytosis.