This will be an open label, multicenter study of subcutaneous HHT (omacetaxine mepesuccinate) therapy of patients with chronic myeloid leukemia (CML) in chronic, accelerated, or blast phase who have failed or are intolerant to tyrosine kinase inhibitor therapy. Patients will be treated with induction course cycles consisting of subcutaneous (SC) HHT 1.25 mg/m² twice daily for 14 consecutive days every 28 days. Patients will be evaluated every 7 days with complete blood and platelet counts while undergoing induction therapy; the number of consecutive doses of HHT or intervals between subsequent cycles may be adjusted, as clinically indicated, according to guidelines provided in the treatment plan.