Currently, less frequent than once weekly subcutaneous epoetin administration regimens were shown to be equally effective and safe as the once-weekly schedules in stable pre-dialyzed and peritoneal dialyzed patients Bioequivalence of once-every-two-weeks and once-weekly subcutaneous administration of the same total dose of epoetin beta for the maintenance phase of anemia treatment in stable, iron-replete, chronic hemodialyzed patients was therefore prospectively investigated.

two treatment schedules will be considered equivalent if the primary efficacy parameters will be simultaneously similar for both groups and in the predefined range of variation. Confidence intervals (CIs) will be used to compare groups. Since the target Hb in dialyzed patients is defined as 11g/dL (110 g/L) by the European Guidelines and as >10 g/dL (100 g/L) by the National Guidelines, with a recommended upper limit of 13 g/dL (130 g/L), the efficacy range for Hb in this study was predefined as 10-12 g/dL (100-120 g/L). The two treatment schedules will be considered to have similar efficacy if the mean Hb in Group 2w will not differ by more than ±0.5 g/dL (±5 g/L) compared to Group 1w during the assessment period. Once similar efficacy established, drug requirements will be compared calculating the ratio of the mean weekly epoetin doses in Group 2w/Group 1w. A range of 0.8 to 1.25 for the ratio is considered sufficient to define bioequivalence. Equivalence of drug usage in the two arms will be accepted if the whole 95% CI for this ratio will be within the above limits.

Lack of difference between group means does not imply similar distribution of treatment effects within each group. The individual hemoglobin change will be used to assess if response to treatment was similarly variable in the two arms. The change in Hb will be calculated for each patient as the difference between the mean Hb during the assessment period and the mean Hb during the baseline phase.