Combination chemotherapy with low-dose cytarabine, homoharringtonine, and granulocyte colony-stimulating factor priming in patients with relapsed or refractory acute myeloid leukemia

As sensitization of leukemic cells with granulocyte colony-stimulating factor (G-csf) can enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML), a pilot study was conducted in order to evaluate the effect of G-csf priming combined with low-dose chemotherapy in patients with relapsed and refractory AML. The regimen, G-HA, consisted of cytarabine 7.5 mg/m2/12 hr by subcutaneous injection, days 1-14, homoharringtonine 1.5 mg/m2/day by intravenous continuous infusion, days 1-14, and G-csf 150 microg/m2/day by subcutaneous injection, days 0-14. Thirty-six AML patients were enrolled, 23 refractory and 13 relapsed. Eighteen patients (50%, 95% confidence interval: 33-67%) achieved complete remission (CR) with a median CR duration of 7.2 months, and two elderly patients continued a regimen of maintenance therapy and remained in remission for 26.3 and 14.1 months, respectively, as of last follow-up. Eight patients (22%) experienced neutropenia (median duration: 6 days; range: 2-22 days). Thirteen of the 36 (36%) developed severe infections. Grade 1-2 nonhematologic toxicities were documented, including nausea and vomiting (20%), liver function abnormality (6%), and heart function abnormality (6%). No central nervous system and kidney toxicity was observed. The G-HA regimen is effective in remission induction for refractory and relapsed AML patients and well tolerated in maintenance therapy in some subgroups of elderly patients. Further studies are necessary to elucidate optimum dose and schedule for this regimen to enhance the treatment efficacy of relapsed or refractory AML patients.