Kazumasa Shimamatsu Shimamatsu Naika Iin (Clinic), Shiseikai Medical Corporation, Chikushino City, Japan Aim: Taking advantage of the characteristics of both darbepoetin (DA) and epoetin (EPO) might be a reasonable option for stabilizing hemoglobin (Hb) control in hemodialysis (HD) patients. The effect of DA assisted by EPO (DA/EPO) on Hb control was evaluated retrospectively in comparison with that of EPO monotherapy. Methods: Twenty-six HD patients whose annual mean Hb values were available for both an EPO monotherapy period and a DA/EPO period were selected for analysis. During the DA/EPO period, DA was given on the second HD day of a week, and EPO was given if needed on the first and third HD days. Under stable DA dosage, when Hb rose >12 g/dL, EPO was eliminated. When Hb decreased <10 g/dL, EPO was added again. The variability of annual mean Hb values from the 26 HD patients during the DA/EPO period was compared with that during the EPO period. Additionally, the distance in Hb (d-Hb; absolute value of difference) between the annual mean Hb values and the target Hb (11 g/dL) during the DA/EPO period was compared with that during the EPO period. Results: The variability of annual mean Hb values during the DA/EPO period was significantly smaller than that during the EPO period (11.2±0.25 g/dL versus [vs] 11.0±0.50 g/dL; the F-test for equality of variance, P<0.001). Additionally, the d-Hb during the DA/EPO period was significantly smaller than that during the EPO period (0.22±0.21 g/dL vs 0.38±0.31 g/dL, P<0.03). The total doses (as EPO equivalents) of DA with EPO were reduced to 82.2% of the baseline EPO dose during the EPO monotherapy period. The expenditure for the DA/EPO period was significantly reduced to 80.9% of that for the EPO monotherapy. Also, the annual total amount of intravenous iron supplementation during the DA/EPO period was significantly reduced compared with that during the EPO period (546±304 mg/year vs 684±314 mg/year, P<0.05). Conclusion: The occasional use of EPO in combination with a stable DA dosage may be useful for Hb control within a narrow range of the target level. Keywords: combination therapy, erythropoiesis-stimulating agents, hemoglobin cycling, hemoglobin SD