Efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection for the treatment of renal anemia in Chinese hemodialysis patients: A randomized, open-label, parallel-group, noninferiority phase III trial

Background: This study was to explore the clinical efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection (recombinant human erythropoietin injection, rHuEPO) for the treatment of anemia associated with chronic kidney failure in Chinese patients undergoing hemodialysis.Method: This study was a multicenter, randomized, open-label, intergroup parallel control phase III noninferiority trial from April 19, 2013 to September 9, 2014 at 25 sites. In this study, the members of the darbepoetin alfa group underwent intravenous administration once per week or once every two weeks. The members of the control drug epoetin alfa group underwent intravenous administration two or three times per week. All subjects underwent epoetin alfa administration during the 8-week baseline period. After that, subjects were randomly assigned to the darbepoetin alfa group or epoetin alfa group. The noninferiority in the changes of the average Hb concentrations from the baseline to the end of the evaluation period (noninferiority threshold: -1.0 g/dl) was tested between the two treatments. The time-dependent hemoglobin (Hb) concentration and the maintenance rate of the target Hb concentration (the proportion of subjects with Hb concentrations between 10.0 and 12.0 g/dl) were also evaluated. Iron metabolism, including changes in the serum iron, total iron-binding capacity, ferritin, transferrin saturation, and comparisons of the dose adjustments between the two groups during the treatment period were analyzed further. Adverse events (AEs) were also observed and compared, and the safety was analyzed between the two treatment groups. The conversion rate switching from epoetin alfa to darbepoetin alfa was also discussed. SAS? software version 9.2 was used to perform all statistical analyses. Descriptive statistics were used for all efficacy, safety, and demographic variable analyses, including for the primary efficacy indicators.Results: Four hundred and sixty-six patients were enrolled in this study, and ultimately 384 cases were analyzed for safety, including 267 cases in the darbepoetin alfa group and 117 cases in the epoetin alfa group. There were 211 cases in the per-protocol set, including 152 cases in the darbepoetin alfa group and 59 cases in the epoetin alfa group. The changes in the average Hb concentrations from the baseline to the end of the evaluation period were -0.07 and -0.15 g/dl in the darbepoetin alfa group and epoetin alfa group respectively. The difference between the two groups was 0.08 g/dl (95% confidence interval [CI]: -0.22 to 0.39), and the lower limit of the 95% CI was -0.22 > -1.0 g/dl. The average Hb concentrations of the two groups were 10.88-11.43 g/dl (darbepoetin alfa) and 10.91-11.38 g/dl (epoetin alfa) during the study period of Weeks 0-28, with the maintenance rates of the target Hb concentration ranging within 71%-87% and 78%-95% in the darbepoetin alfa group and epoetin alfa group respectively. During the period of comparison between the two groups, the incidence of AEs in the darbepoetin alfa group was 61.42%, while in the epoetin alfa group it was 56.41%. All of the adverse events and reactions in the study were those commonly associated with hemodialysis.Conclusion: The overall efficacy and safety of darbepoetin alfa for the treatment of Chinese renal anemia patients undergoing hemodialysis are consistent with those of epoetin alfa.