Supplementary Material for: A Comparison of the Safety and Efficacy of HX575 (Epoetin Alfa Proposed Biosimilar) with Epoetin Alfa in Patients with End-Stage Renal Disease

Background: HX575 (biosimilar epoetin alfa) was approved in Europe in 2007 for the treatment of chronic kidney disease (CKD)-related anemia. This study assessed the clinical equivalence of HX575 with the US-licensed reference epoetin alfa (Epogen®/Procrit®, Amgen/Janssen) following subcutaneous (SC) administration in dialysis patients with CKD-related anemia. Methods: This randomized, double-blind, parallel-group, multicenter study (NCT01693029) was conducted at 49 US clinical sites. Eligible patients were aged ≥18 years, had end-stage renal disease, were on hemodialysis or peritoneal dialysis for ≥6 months (or ≥12 months in the case of a failed kidney transplant), and were receiving treatment with stable SC doses of epoetin alfa. Eligible patients also had mean hemoglobin (Hb) concentration between 9.0 and 11.5 g/dL during the screening period. The primary endpoint was the mean absolute change in Hb concentration between the screening/baseline period (week-4 to week-1) and the evaluation period (weeks 21 to 28). Results: Hb values at the end of the evaluation period and the Hb change from baseline to evaluation period were similar between treatment groups. The estimated difference between groups in mean absolute change in Hb concentration was –0.093 g/dL, with 90% CI (–0.23 to 0.04) entirely within the pre-specified equivalence limits (–0.5 to 0.5 g/dL). The safety profile of each medicine was similar and as expected in dialysis patients, and neither method of treatment led to the development of neutralizing, clinically relevant antibodies. Conclusions: SC HX575 in dialysis patients with renal anemia was therapeutically equivalent to the reference medicine in terms of maintaining stable Hb levels and safety.