Dosing Penalty of Erythropoiesis-Stimulating Agents after Switching from Originator to Biosimilar Preparations in Stable Hemodialysis Patients

To the Editor: The efficacy of ESA biosimilars has been tested mainly in the few studies needed for marketing authorization,1-5 whereas data from individual self-reported clinical experience are lacking. Such information, together with pharmacovigilance data, is key to obtaining reassurance regarding the safety of these products. Of note, 2 studies of efficacy when switching from originator to biosimilar in hemodialysis patients have reported a dosing penalty (ie, requiring higher doses to maintain Hb level) of 4% to 13% for HX575 (epoetin alfa; Binocrit) and 10% to 15% for SB309 (epoetin zeta; Retacrit). 4,5 Dosing penalty for biosimilars is relevant not only for cost reasons, but also when considering the significant association of higher ESA dose with adverse outcomes.6 All manufacturers recommend using the lowest effective dose for correcting anemia.