Treatment with Homoharringtonine and Cytarabine in Patients with High Risk Acute Myelogenous Leukemia (AML).

Objective: To evaluate response of homoharringtonine in patients with high risk AML or as a second-line therapy in patients with AML refractory to anthracycline based chemotherapy.

Patients and methods: From Jan 1998-Jan 2006, there were 66 patients enrolled in this regimen. Male:female=40:26. Median age was 47 (17–69). There were 48 newly diagnosed AML, 5 relapsed AML and 13 secondary AML (secondary to MDS) in this group. Among these patients, there were 40 patients untreated previously — 20 patients had unfavourable chromasomal abmormalities, 10 patients had pgp positive, 10 patients had normal chromasome but high CD34 expression on leukemic cells. The remaining 26 patients were previously treated with daunorubincin or mitoxantrane combined with cytarabine at least two cycles and failed to achieve response. Homoharringtonine was given at dose of 4mg/m2/d(2.5mg/m2/d for age≥60 years) intraveniously for 7 days. Cytarabine was given at dose of 100mg/m2/d at same time. The therapy was repeated every 21 days.Post remission therapy was divided into two cohot —same regimen maintainance in 20 cases and cytarabine 1g/m2/d q12h for 4 days at least 4 cycles in 20 cases.

Results: 40/66 patients achieved complete remission. 3/66 achieved partial remission. In patients refactory to anthracycline based regimen, the CR rate was 57.7%(15/26). In previously untreated high risk AML patients,the CR rate was 62.5%(25/40). Median disease free survival were 4.25 months (2–30) in cohot 1 and 18 months (12–47) in cohot 2 (P<0.05). CD95(APO-1/Fas) was tested by flow cytometry during treatment. APO-1/Fas (CD95) increased from (9.56±5.58)% to (25.64±0.70)% after induction chemotherapy. Main toxicities were marrow suppression and infection. There were 7 early deaths, 5 patients died of cerebral hemorrage and 2 cardiovascular events.

Conclusions: Homoharringtonine is effective in patients with high risk AML. It is also a choice of second line therapy in patients refractory to anthracycline based chemotherapy. Intensive post remission therapy is superior to conventional dose maintainance therapy in high risk AML. One of the ways for homoharringtonine to induce leukemic cell apoptosis is probably through Fas pathway.