Introduction: The primary objective of the trial was to prove the therapeutic equivalence of epoetin zeta to epoetin alfa when administered subcutaneously for maintaining target hemoglobin (Hb) in patients with renal anemia on chronic hemodialysis. Additional information was provided on the safety and tolerability of epoetin zeta with particular focus on the formation of anti-erythropoietin antibodies.
Methods: A total of 462 patients were randomized to either epoetin zeta or alfa for 28 weeks after an open period of dose adjustment of 12-16 weeks with only epoetin zeta. The aim of treatment was to maintain Hb between 10.0-12.0 g/dL with constant epoetin dosage. Primary endpoints were the mean Hb level and the mean weekly epoetin dosage during the last 4 weeks of treatment. Safety endpoints were the occurrence of anti-erythropoietin antibodies, incidence of Hb levels above 13 g/dL, ratings of tolerability, and adverse events (AEs).
Results: The mean Hb level (+/-SD) during the last 4 weeks of treatment was 10.94+/-0.84 g/dL (epoetin zeta) and 11.02+/-0.94 g/dL (epoetin alfa). The 95% confidence interval (CI) (''C0.28 g/dL to 0.12 g/dL) was entirely within the predefined equivalence range (+/-0.5 g/dL). The mean weekly epoetin dosage per body weight over the last 4 weeks of treatment was 97.0+/-94.3 IU/kg/week (epoetin zeta) and 86.0+/-78.0 IU/kg/week (epoetin alfa). The 95% CI (''C8.06 IU/kg/week to 29.96 IU/kg/week) was also within the predefined equivalence range of +/-45 IU/kg/week. The most common AEs were infections and infestations (15.1% of patients on epoetin zeta and 14.8% of patients on epoetin alfa). None of the patients developed anti-erythropoietin antibodies.
Conclusions: Epoetin zeta, administered subcutaneously, is equivalent to epoetin alfa in respect of its clinical efficacy. The safety profile of both products is similar: no unexpected AEs were observed, no patients developed anti-erythropoietin antibodies, and both epoetin preparations were well tolerated.