Insights in anemia management.

After almost 20 years, anemia in chronic kidney disease (CKD) and its treatment remain the focus of multiple questions for clinicians and investigators. The optimal hemoglobin (Hb) for patients with CKD is controversial and different targets are probably required for different populations. The current literature does not support an upper Hb target >12 g/dl and there is a clear demonstration of increased risk with Hb targets >13 g/dl. With this narrow target of 11-12 g/dl, fluctuations in Hb concentration are commonly observed in patients being treated with erythropoiesis-stimulating agents (ESAs). Studies to date provide a suggestion of an association between Hb cycling and mortality, but they have been primarily exploratory in nature and clinical trials comparing treatment strategies leading to different degrees of Hb variability are needed. The great majority of incidences of pure red cell aplasia (PRCA) was associated with ESA therapy and was first recognized several years ago after a change in the formulation in which human serum albumin was eliminated and replaced by polysorbate-80 in patients on epoetin alfa (Eprex). Years later, a registry (PRIMS) was established by the health authorities as part of a reapproval of the subcutaneous route to confirm that the cause of PRCA has been eliminated. The ongoing PRIMS study is a 3-year observation period prospective multicenter and international (Europe and Australia) registry that could serve as a model for assessment of the immunogenicity profiles of currently marketed and future ESAs. The association with a change in formulation makes PRCA of interest to the biotechnology industry as well as the medical community because it raises the broader question of the potential immunogenicity of biopharmaceuticals in general.