Hemoglobin targets for the anemia in patients with dialysis-dependent chronic kidney disease: a meta-analysis of randomized, controlled trials.

BACKGROUND: Anemia is extremely common among dialysis patients and underlies some of the symptoms associated with reduced kidney function, including fatigue, depression, reduced exercise tolerance, and dyspnea. OBJECTIVES: A clearer cognition of the prognosistic impact of hemoglobin (Hb) or hematocrit (Hct) target for the outcomes of dialysis patients is urgent. This article aims to establish the suitable hemoglobin in order to provide clinical guidance. METHODS: MEDLINE, EmBase, the Cochrane Library and other databases were searched with both MeSH terms and keywords to gather randomized controlled trials that assessed all-cause mortality, cardiovascular events, fistula thrombosis, infectious diseases and transfusion among dialysis-dependent patients using erythropoiesis-stimulating agents. The meta-analysis was accomplished via Revman 5.3 version. FINDINGS: Totally, nine eligible studies were included, with study subjects involving 3228 patients. There was a significantly higher risk of fistula thrombosis without heterogeneity (RR 1.34, 95% CI 1.15-1.55; p < 0.05) in the higher Hb target group than in the lower Hb target group in the fixed effects model. However, no significant difference was found in all-cause mortality in the fixed effects model (RR 1.09, 95% CI 0.93-1.27; p = 0.30), cardiovascular events (RR 0.77, 95% CI 0.31-1.92; p = 0.58), infectious diseases (RR 0.69, 95% CI 0.24-1.96; p = 0.49) and transfusion (RR 0.92, 95% CI 0.42-1.99; p = 0.82) in the random effects model between the higher Hb target group and the lower Hb target group. DISCUSSION: The results favor lower Hb target. To target lower Hb target when treating dialysis patients with anemia may decrease the risk of fistula thrombosis without increasing the risk of death, cardiovascular events, infectious diseases and transfusion.

An Integrated Approach for a Structural and Functional Evaluation of Biosimilars: Implications for Erythropoietin.

BACKGROUND: Authorization to market a biosimilar product by the appropriate institutions is expected based on biosimilarity with its originator product. The analogy between the originator and its biosimilar(s) is assessed through safety, purity, and potency analyses. OBJECTIVE: In this study, we proposed a useful quality control system for rapid and economic primary screening of potential biosimilar drugs. For this purpose, chemical and functional characterization of the originator rhEPO alfa and two of its biosimilars was discussed. METHODS: Qualitative and quantitative analyses of the originator rhEPO alfa and its biosimilars were performed using reversed-phase high-performance liquid chromatography (RP-HPLC). The identification of proteins and the separation of isoforms were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and two-dimensional gel electrophoresis (2D-PAGE), respectively. Furthermore, the biological activity of these drugs was measured both in vitro, evaluating the TF-1 cell proliferation rate, and in vivo, using the innovative experimental animal model of the zebrafish embryos. RESULTS: Chemical analyses showed that the quantitative concentrations of rhEPO alfa were in agreement with the labeled claims by the corresponding manufacturers. The qualitative analyses performed demonstrated that the three drugs were pure and that they had the same amino acid sequence. Chemical differences were found only at the level of isoforms containing N-glycosylation; however, functional in vitro and in vivo studies did not show any significant differences from a biosimilar point of view. CONCLUSION: These rapid and economic structural and functional analyses were effective in the evaluation of the biosimilarity between the originator rhEPO alfa and the biosimilars analyzed.

Influence of safety warnings on ESA prescribing among dialysis patients using an interrupted time series.

BACKGROUND: In March, 2007, a black box warning was issued by the Food and Drug Administration (FDA) to use the lowest possible erythropoiesis-stimulating agents (ESA) doses for treatment of anemia associated with renal disease. The goal is to determine if a change in ESA use was observed following the warning among US dialysis patients. METHODS: ESA therapy was examined from September 2004 through August 2009 (thirty months before and after the FDA black box warning) among adult Medicare hemodialysis patients. An interrupted time series model assessed the impact of the warnings. RESULTS: The FDA black box warning did not appear to influence ESA prescribing among the overall dialysis population. However, significant declines in ESA therapy after the FDA warnings were observed for selected populations. Patients with a hematocrit≥36% had a declining month-to-month trend before (-164 units/week, p=<0.0001) and after the warnings (-80 units/week, p=.001), and a large drop in ESA level immediately after the black box (-4,744 units/week, p=<.0001). Not-for-profit facilities had a declining month-to-month trend before the warnings (-90 units/week, p=.009) and a large drop in ESA dose immediately afterwards (-2,487 units/week, p=0.015). In contrast, for-profit facilities did not have a significant change in ESA prescribing. CONCLUSIONS: ESA therapy had been both profitable for providers and controversial regarding benefits for nearly two decades. The extent to which a FDA black box warning highlighting important safety concerns influenced use of ESA therapy among nephrologists and dialysis providers was unknown. Our study found no evidence of changes in ESA prescribing for the overall dialysis population resulting from a FDA black box warning.

Fluctuations of haemoglobinaemia in chronic haemodialysis patients.

In March 2008 and June 2009, an ad hoc working group of nephrologists discussed the status of anaemia therapy with erythropoiesis-stimulating agents [ESA] in patients on chronic haemodialysis, the phenomenon of fluctuations of haemoglobinaemia, and the need for individualisation of ESA treatment. The working group put together the following statements: (1) ESAs increase the haemoglobin concentration and adaptations of the ESA dose adjust the response according to a negative-feedback loop. The long lag time between an ESA dose change and its effect on erythropoiesis is cumbersome. The optimal haemoglobin target concentration is different for every haemodialysis patient; the lowest haemoglobin concentration upon which one could consistently demonstrate a positive subjective and objective clinical benefit in chronic dialysis is 11 g/dL, in contrast to the lowest haemoglobin concentration of 10 g/dL recommended in the current EMEA label for ESAs. (2) Intra-individual fluctuation of haemoglobinaemia over time is unavoidable, not only due to the ESA dose/haemoglobin response interaction, but also, and more importantly, due to the occurrence of acute illnesses and exacerbations of co-morbid conditions. Many different methodologies to characterise haemoglobin variability have been described but there is currently no universally applied definition of the phenomenon. (3) An impact of the haemoglobin level and the amplitude of the haemoglobin fluctuations on patient outcome has been observed. Without disclosing any causal relationship, worse outcomes were associated with haemoglobin fluctuations around the lower target level, but later on, more simply linked to the relative time spent below the haemoglobin concentration of 11 g/dL and to the administration of inappropriately high ESA doses in order to achieve the recommended haemoglobin target range. A plausible mechanism might be that acute illnesses blunt the patients' basal ESA sensitivity; this leads to subnormal and/or varying haemoglobin levels, currently initiating an ESA dose increase. The longer it takes the patient to recover from the acute illness, the more the prolongation of the clinically poor condition is to some extent maintained by the persistence of low haemoglobinaemia and/or by the administration of high ESA doses, and, as such, on their turn possibly contributing to an ultimate poor outcome. In the absence of clinical trials, recommendations should be offered how to proceed with the administration of ESAs as optimal as possible in periods of clinical instability.

An alternative to animal testing in the quality control of erythropoietin.

A physico-chemical method has been developed as an alternative to the current bioassay in normocythaemic mice for estimating the biological activity of erythropoietin batches. Capillary zone electrophoresis was used for quantification of the isoforms and their substructures were further elucidated by N-glycan mapping techniques. The analytical study was carried out on a total of 40 batches of epoetin beta which were selected to cover an adequate range of precisely established potency values. The relationship between the biological and chemical parameters was evaluated statistically in order to identify suitable covariates for the prediction of the biological activity. Out of several alternatives, a prediction model which is based on the percentages of isoforms per batch and the degree of sialidation was selected and tested. This model is comparable in terms of accuracy to the established in vivo bioassay, but is far superior in terms of precision. Further advantages of the method are improved animal welfare and savings in time and effort. The question whether the prediction model already meets the requirements for replacing the bioassay according to the ICH guideline Q6B is discussed.

Optimization and qualification of capillary zone electrophoresis method for glycoprotein isoform distribution of erythropoietin for quality control laboratory.

The European Pharmacopoeia (Ph. Eur.) monograph for Erythropoietin Concentrated Solution describes a capillary zone electrophoresis method for identification of recombinant human erythropoietin. However, this method has shown poor reproducibility due to inadequate capillary conditioning. We have modified the Ph. Eur. method to make it more robust and suitable for the quality control laboratory for the analysis of epoetin alfa and epoetin alfa after formulation with polysorbate 80. This study qualified the modified method by showing improved robustness and reproducibility. The study also characterized and qualified a secondary standard of epoetin alfa as a substitute for the primary standard, Ph. Eur. erythropoietin Biological Reference Preparation, which is available in limited supply. Four sets of analyses were performed to assess repeatability, intermediate precision, and the secondary standard. The results showed that the modified method is suitable for its intended purpose to test epoetin alfa and formulated epoetin alfa samples. The epoetin alfa secondary standard is a suitable substitute for the primary standard. Further, we developed a procedure for the removal of polysorbate 80 from formulated epoetin alfa, allowing the material to be analyzed by the modified Ph. Eur. method.

Impact of illegal trade on the quality of epoetin alfa in Thailand.

BACKGROUND: Reports from the World Health Organization have suggested that counterfeit medicines pose a serious problem in developing countries. An investigation of anti-erythropoietin antibody-mediated pure red cell aplasia in Thailand found evidence of drug smuggling, which may have serious safety implications. OBJECTIVE: This study assessed the authenticity and quality of epoetin alfa samples in Thailand. METHODS: Samples of epoetin alfa-prefilled syringes were collected from the pharmacies at 2 major hospitals (62 samples), 8 retail pharmacies (41 samples), and Thai authorities (30 samples confiscated from smugglers at 2 airports, and 6 samples from a condominium used by smugglers). These samples were tested against the European Union Pharmacopeia specifications for aggregate content in epoetins of <2%. The integrity of epoetin alfa distribution channels, coldchain processes (maintenance at 2 degrees C-8 degrees C), primary and secondary packaging components (eg, batch number, expiration date, appearance, letter size), and company's confidential features (eg, nature of the ink, type and quality of the paper, other covered features) were also investigated. The main outcome measures were protein aggregate content, determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blotting; and isoform distribution, assessed by isoelectric focusing and Western blotting. RESULTS: Epoetin alfa samples obtained from the company's cold-chain and authorized distribution channels met all quality standards, as did all epoetin alfa samples obtained from the hospital pharmacies. However, evidence showed that some samples were being smuggled or sold illegally through certain unauthorized retail pharmacies. The epoetin alfa samples obtained from both airports and the condominium were stored improperly at room temperature. Aggregate levels exceeded the specification of <2% in 11 samples from 2 of the retail pharmacies (range, 1.2%-3.1%), 15 samples from the Dongmuang Airport (range, 2.2%-17.0%), and all 6 samples from the condominium (range, 10.5%-19.8%). All samples from the 2 hospitals, 8 retail pharmacies, and Suvarnabhumi Airport had the authentic 6 isoform bands. Samples from Dongmuang Airport and the condominium appeared to have the 6 characteristic bands, but positive confirmation was difficult because of band smearing caused by a high level of aggregates. All features of primary and secondary packaging were found to be authentic. CONCLUSIONS: This investigation found evidence that some epoetin alfa samples were smuggled into Thailand without proper cold chain, contained high levels of protein aggregates, and were sold illegally through certain retail pharmacies. The Thai authorities have intervened to stop such unauthorized products from reaching patients. Strenuous efforts must be made to prevent illegal cross-border smuggling of biopharmaceuticals without proper cold chain because of the serious safety implications for patients in developing countries.

Biochemical assessment of erythropoietin products from Asia versus US Epoetin alfa manufactured by Amgen.

We compared the physical and chemical properties of purported copies of recombinant human erythropoietin (rHuEPO) purchased from Korea, China, and India with the innovator product, Epoetin alfa, manufactured by Amgen Inc. The products were characterized for similarity in the types of glycoforms present, the relative degree of unfolding, in vitro potency, presence of covalent aggregates, and presence of cleavage products using established analytical methods. All products were different from Epoetin alfa (Epogen). The purported copies of rHuEPO from Korea, India, and China contained more glycoforms and other impurities. The in vitro relative potency varied for each product when based on the labeled concentration, while the concentration based on ELISA analysis brought the relative potency, for most products closer to 100%. These data emphasize potential biochemical discrepancies resulting from different cell lines and manufacturing processes. Concentrations varied within products and did not always match the information provided on the product label. As it is not possible to reliably correlate such biochemical discrepancies to clinical consequences, or the lack thereof, these data support the need for extensive preclinical testing and clinical testing of all investigational products as not all safety and efficacy aspects can be assessed during preclinical evaluation.

Impact of the change in CMS billing rules for erythropoietin on hemoglobin outcomes in dialysis patients.

On April 1, 2006, new Centers for Medicare and Medicaid Services (CMS) rules for billing erythropoietin (EPO) for dialysis patients went into effect. Two key provisions of the rules were to cap the dose for a single patient at 500,000 IU/month and to mandate a 25% reduction in dose for patients whose latest hemoglobin (HGB) or hematocrit (HCT) in the prior month exceeded 13 g/dl or 39%, respectively. The purpose of this article is to document the effect of the rules change on HGB outcomes in a single large dialysis provider whose computer system was modified to enforce the rules. HGB and EPO doses for 5 months following the implementation were analyzed retrospectively. The most noteworthy observation is that while the rule appears to have reduced the percentage of patients with an HGB of >13 g/dl slightly, it has also increased the percentage of patients with HGB in the medically undesirable range of <11 g/dl.