Phase II Study of Low-dose Continuous Infusion Homoharringtonine in Refractory Acute Myelogenous Leukemia

Thirty-one patients with a diagnosis of refractory acute myelogenous leukemia received homoharringtonine as their first (15 patients) or second (16 patients) salvage therapy. Homoharringtonine was given as a continuous infusion of 2.5 mg/m2 daily for 15 to 21 days to 13 patients (schedule 1), and of 3.0 mg/m2 daily for 15 days in 18 patients (schedule 2). Overall, one patient achieved complete remission (3%), and three (10%) had a hematologic improvement with normalization of the marrow and peripheral blood picture except for persistent thrombocytopenia. Six patients (19%) demonstrated prolonged myelosuppression, three (23%) on schedule 1 and three (17%) on schedule 2. Cardiovascular complications were minimal consisting of hypotension in one patient (3%) and supraventricular arrhythmias in two patients (6%). Hyperglycemia was observed in 42% of patients and was significant in 10%. The authors conclude that homoharringtonine, at the dose schedule investigated, has definite but low antileukemic efficacy. The low-dose continuous infusion schedule was associated with prolonged myelosuppression but no serious cardiovascular complications. The role of such therapy in myeloproliferative disorders, especially chronic myelogenous leukemia, deserves consideration.