Eltrombopag Olamine in Treating Thrombocytopenia in Patients With Chronic Myeloid Leukemia or Myelofibrosis Receiving Tyrosine Kinase Therapy

Inclusion Criteria: * CML patients in chronic phase receiving treatment with any Food and Drug Administration (FDA) approved TKI; or CML patients in accelerated or blastic phase who are considered to be in this phase because of thrombocytopenia or because of clonal evolution and with no other criteria for accelerated/blastic phase or patients with myelofibrosis receiving treatment with FDA approved TKI and with peripheral blood and/or bone marrow blasts =\< 10% * Grade \>= 3 thrombocytopenia (platelets \< 50 x 10\^9/L) after the first 3 months of therapy with the TKI for patients with CML and platelets \< 100 x 10\^9/L for patients with MF after the first 3 months of therapy; thrombocytopenia must be either recurrent (i.e., second or greater episode of thrombocytopenia) or having required dose reductions of the TKI * Subject is anticipated to have therapy with TKI continued for \>= 3 months * Total bilirubin =\< 1.5 x upper limit of normal (ULN) (except for Gilbert's syndrome) * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) \< 3 x ULN * Creatinine =\< 2 x ULN Exclusion Criteria: * CML patients in accelerated or blastic phase except for those who are considered to be in this phase because of thrombocytopenia or because of clonal evolution and with no other criteria for accelerated/blastic phase; or myelofibrosis patients who have transformed to acute leukemia or have \>= 10% blasts in peripheral blood and/or in bone marrow * Thrombocytopenia that is co…