CERA: third-generation erythropoiesis-stimulating agent

Introduction of a PEGylated EPO conjugate as internal standard for EPO analysis in doping controls

Immunopurification of doping control samples is a mandatory necessity in erythropoietin (EPO) analysis during a confirmation procedure; moreover, it has become common practice to also immunopurify samples for the initial testing procedure. Typically used materials (e.g., Stemcell purification plate and MAIIA purification kit) rely on anti-EPO antibodies for purification. Also, the detection of EPO after electrophoretic separation and western blotting is based on a monoclonal anti-EPO antibody, clone AE7A5, directed against a 26 amino acid sequence of the N-terminal region of human EPO. While the electrophoretic separation and blot transfer efficiency can be monitored with reference standards and quality control samples, it is presently not possible to monitor the functionality of the entire sample preparation procedure. The reliance on antibodies for both purification and detection has complicated the implementation of an internal standard (ISTD). In this study, customized EPO-polyethylene glycol (PEG) conjugates were synthesized as potential ISTDs and assessed as to their compatibility with existing sample preparation procedures for urine and blood sample analysis using the most common immunopurification techniques. Moreover, probing for the impact of the ISTD on sodium N-lauroylsarcosinate ("sarcosyl") polyacrylamide gel electrophoresis (SAR-PAGE)-based EPO analysis concerning potential interference with target analytes was conducted. The presented data demonstrate that a 12-kDa PEG residue attached to human EPO represents a particularly useful construct to serve as ISTD for erythropoietin-receptor agonist (ERA) analysis. The conjugate is applicable to both urine and blood testing using the commonly employed purification techniques, supporting and improving result interpretations especially concerning specimens where the natural abundance of human EPO is low.

The Associations between Erythropoietic Response with Inflammation Markers and Perfluorinated Chemicals in Hemodialysis Patients

Erythropoiesis-stimulating agents (ESA) are used to treat anemia in hemodialysis (HD) patients. We investigated the role of inflammation and accumulation of environmental toxins (perfluorinated chemicals (PFCs), such as perfluorooctanoic acid and perfluorooctane sulfonate) in the erythropoietic response of HD patients who receive a fixed monthly continuous erythropoietin receptor activator (CERA) dosage. Forty-five patients underwent three successive phases of ESA treatment for two months each (phase one: 100 µg CERA once monthly; phase two: 50 µg CERA twice monthly; phase three: 100 µg CERA once monthly). Patient data were collected to determine the association of various factors with erythropoietic response (change in hematocrit). Liquid chromatography-tandem mass spectrometry was used to analyze perfluorinated chemicals. Twenty-eight patients exhibited a poor erythropoietic response that was significantly associated with: age > 80 years, initial hematocrit > 36%, glucose > 200 mg/dL, alanine aminotransferase > 21 U/L, c-reactive protein > 1 mg/dL, interleukin-6 > 10 ng/mL, lactate dehydrogenase ≤ 190 U/L, and chloride ≤ 93 mEq/L. There was also a borderline significant association between inflammation and PFCs, although PFCs failed to show any impact on ESA response. Age, glucose, chloride, liver function, and inflammation may be associated with cost-effective fixed CERA dosage administered at an increased frequency.

Visualization of 57Fe-Labeled Heme Isotopic Fine Structure and Localization of Regions of Erythroblast Maturation in Mouse Spleen by MALDI FTICR-MS Imaging

Epoetin beta pegol (continuous erythropoiesis receptor activator; C.E.R.A.), or methoxy-polyethylene glycol-modified epoetin beta, is a long-acting erythropoiesis stimulating agent (ESA) that effectively maintains hemoglobin levels. It promotes proliferation of erythroid progenitor cells in hematopoietic organs and leads to increased reticulocyte and hemoglobin levels. However, the detailed erythropoietic effects of various ESAs on their target organs have yet to be clarified, and new approaches are needed to analyze tissue iron localization with structural information. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) techniques are widely used in basic pharmaceutical research. High-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) imaging enables the spatial mapping and identification of biomolecules. In this study, mice administered with C.E.R.A. were fed a diet containing the stable iron isotope ⁵⁷Fe. The ⁵⁷Fe-heme⁺ isotopic fine structure peak (m/z 617.1772) was separated from the non-labeled heme⁺ isotopic peak (Δ0.0029) by FTICR-MS with a resolving power of more than 500,000. We optimized the platform to analyze the distribution of ⁵⁷Fe-heme in the spleen using MALDI FTICR-MS imaging. The combination of the ultrahigh resolution power of FTICR-MS and a stable isotope labeling technique has the potential to be very effective in basic pharmaceutical research. Graphical Abstract ᅟ.

Epoetin β pegol (continuous erythropoietin receptor activator, CERA) is another choice for the treatment of anemia in myelodysplastic syndrome: a case report

Background

In most patients, anemia is present when myelodysplastic syndrome is diagnosed. Although darbepoetin α is the first-choice supportive therapy for low-risk myelodysplastic syndrome, half of all patients develop a loss of response to darbepoetin α within 12 months. However, few reports have described supportive therapy after the loss of response to darbepoetin α.

Case presentation

We herein present a case involving a 65-year-old Japanese woman with low-risk myelodysplastic syndrome whose erythropoiesis-stimulating agent treatment was switched from darbepoetin α to epoetin β pegol (continuous erythropoietin receptor activator) to treat transfusion-dependent anemia. The frequent transfusions required to treat the anemia resulted in transfusion-associated circulatory overload. The transfusion-dependent anemia was initially treated with darbepoetin α, which negated the requirement for transfusion. However, after 12 months of darbepoetin α therapy, the hemoglobin concentration sharply declined. We switched her therapy from darbepoetin α to continuous erythropoietin receptor activator to avoid transfusion. After initiation of continuous erythropoietin receptor activator therapy, the hemoglobin concentration gradually increased and transfusion was not required. At the time of writing, no progression of the anemia had occurred.

Conclusions

Although darbepoetin α is the first-choice supportive therapy for low-risk myelodysplastic syndrome, continuous erythropoietin receptor activator might be considered the second-choice therapy.

Fixed dose of long-acting erythropoietic stimulating agents at higher frequency improves appetite, reduces inflammation and corrects anaemia in patients on haemodialysis

Anaemia is an important issue in patients undergoing haemodialysis. We aimed to identify a better dosing schedule of a fixed monthly dose of continuous erythropoietin receptor activator (CERA) in patients with chronic kidney disease (CKD) on haemodialysis. The CERA dosing schedule included 100 μg once monthly for 2 months, 50 μg twice monthly for 2 months and then 100 μg once monthly for two months. The effectiveness was determined by comparing haematocrit, nutritional status (serum protein and albumin) and inflammatory markers (tumour necrosis factor (TNF)-α, interleukin (IL)-1, IL-6 and Hepcidin) at the beginning of the study with those at the end of the study. Forty-seven out of 67 patients completed the trial. At the end, haematocrit was significantly higher (34.51 vs 33.22%, P=.004), levels of inflammatory markers were significantly lower (TNF-α (30.71 vs 35.67 ng/mL, P=.007), IL-6 (5.12 vs 7.95 ng/mL, P=.033), hepcidin (60.39 vs 74.39 ng/mL, P=.002)), blood glucose levels were significantly lower (112.40 vs 139.02 mg/dL, P=.003) and albumin was significantly higher (4.11 vs 3.98, P=.001). Patients with a better than average response had a lower initial number of red blood cells (3.3 vs 3.6 × 10(6) /mm(3) , P=.025) and a lower IL-1 (3.8 vs 12.9 ng/mL, P=.01). They also had significantly lower blood glucose levels at the end. (91.3 vs 124.0 mg/dL, P=.03). We demonstrate that a fixed monthly dose of CERA at a twice monthly dosing schedule improves nutrition, reduces the inflammation and corrects anaemia in patients on haemodialysis. This finding may provide a new strategy for treating CKD-related anaemia.

Rise in RBC aggregability and concomitant decrease in blood pressure 10 days after injection of the long acting erythropoietin analogue methoxy polyethylene glycol-epoetin-β (MIRCERA®)

Erythropoietin (EPO) is a major regulator of blood viscosity. Its long lasting action analogue methoxy polyethylene glycol-epoetin-β (MIRCERA®) seems to be also employed in modern doping. We took the opportunity of a study aiming at developing a detection of recent MIRCERATM injection in the context of doping detection to assess the effects of this EPO analogue on red blood cells (RBC) aggregation. A single dose 200 μg of MIRCERA® was injected to 10 male volunteers and blood samplings were drawn over 24 days. After injection a decrease in mean corpuscular volume at day 2 (p < 0.01) and day 10 (p < 0.02), a rise in reticulocyte count (p < 0.001) between day 4 and day 17 and a decrease in ferritin a day 5 (p < 0.05) was observed. Hemoglobin decreased at day 4 (p < 0.005). Hematocrit was unchanged. There was a dramatic (+67%) increase in RBC aggregation index "M" (from 9.49±1.01 to 17.66±1.8, p < 0.01). A decrease in systolic blood pressure was observed during the period from day 4 to day 17 (at day 10: -11.90±2.28 mmHg, p < 0.001; at day 17: -15.80±2.83, p < 0.001). There was also a decrease in diastolic blood pressure, mean and pulse pressure. Correlations between this decrease in blood pressure and "M" did not reach significance but pulse pressure was positively correlated to "M" (r = 0.743, p < 0.05).These data show that the long acting erythropoietin analogue MIRCERA® strongly increases RBC aggregation parallel to a decrease in blood pressure, but a possible causative link between the two events is not clearly evidenced.

Shift from darbepoetin-α to continuous erythropoietin receptor activator decreases serum aluminium concentration in patients on hemodialysis

OBJECTIVE

The response of erythropoietic stimulating agents (ESA) in uremic patients may be associated with the changes of biochemical parameters, metal elements and inflammation status during the shift from one ESA to another.

METHOD

We compared changes in above mentioned factors after switching from darbepoetin-α (DPO) 20μg weekly for 10 weeks to continuous erythropoietin receptor activator (CERA) 100μg monthly for 10 weeks in uremic patients on hemodialysis. The haematocrit (Hct), metal elements and inflammation status are the primary outcome. Subjects included 54 patients without transfusion or bleeding or additional ESAs. Responders (IR, n=36) were defined as patients with an increase in Hct after the swtich.

RESULT

Although there was no significant difference in overall mean Hct after the switch (p=0.135), there are significantly greater mean number of red blood cells (RBC) (p=0.006), higher platelet numbers (p=0.001), larger RBCs (p=0.017) and higher creatinine (p=0.04) and total cholesterol (T-CHOL) (p=0.003) levels. Mean overall aluminium (Al) level decreased significantly (p=0.001). C-reactive protein (CRP) also decreased (p=0.016). The overall LDH increased (p=0.049) and potassium decreased significantly (p=0.036), which indicating active erythropoiesis. The calcium (Ca) level was significantly higher (p=0.034) and phosphate was significantly lower (p=0.028) after the shift. Although there was no significant increase in overall levels of parathyroid hormone (PTH) after the shift (p=0.061), but the pre-shift and post-shift PTH level was significantly higher in IRs than in non-IRs (p=0.003 and p=0.027, respectively). IRs had a significantly lower initial T-CHOL (p=0.03) and initial CRP (p=0.012) than non-responders, which may be related to lower inflammation.

CONCLUSION

We found the shift from DPO to CERA results in lower Al levels, a reduced inflammatory response, and an increase in RBC number and PTH level in uremic patients on hemodialysis.

Therapeutic oligonucleotides with polyethylene glycol modifications

In the field of oligonucleotide drugs, the attachment of PEG is a well-established strategy to prevent enzymatic degradation and avoid renal elimination. Pegaptanib and other oligonucleotides in clinical development utilize the attachment of linear or branched high molecular weight PEG chains for increase of accumulation and duration of the effect after local or systemic application. The length of PEG chains is decisive for the pharmacokinetic and pharmacodynamic effects. Longer chains increase circulation times, but generally decrease gene-silencing efficiencies for antisense and siRNA agents and binding affinities for aptamers. Shorter chains are less efficient in preventing renal filtration, but have also less impact on the gene-silencing machinery and binding kinetics.

BiOsimilaRs in the management of anaemia secondary to chemotherapy in HaEmatology and Oncology: results of the ORHEO observational study

Background

The approval of epoetin biosimilars in the European Union requires extensive scientific evaluation and stringent regulatory procedures, including post-marketing studies. The ORHEO (place of biOsimilaRs in the therapeutic management of anaemia secondary to chemotherapy in HaEmatology and Oncology) study was an observational, longitudinal, multicentre study performed in France to evaluate the efficacy and safety of biosimilar epoetins for the treatment of chemotherapy-induced anaemia (CIA) in the clinical setting.

Methods

Patients >18 years with CIA (haemoglobin [Hb] <11 g/dL) in association with solid tumours, lymphoma or myeloma and eligible for treatment with an epoetin biosimilar were included in this study. Patient characteristics were recorded at baseline along with anaemia-related information, such as observed and target Hb (as chosen by the treating clinician), brand and dose of epoetin biosimilar prescribed, and details of any other treatments. Patients were then followed-up at 3 and 6 months. The primary endpoint was Hb response (defined as Hb reaching ≥10 g/dL, an increase of Hb ≥1 g/dL since inclusion visit or reaching physician-defined target Hb, with no blood transfusions in the 3 weeks prior to measurement). Other endpoints included adverse events, achievement of target Hb and associated treatments.

Results

Overall, 2333 patients >18 years (mean age 66.5 years) with CIA (haemoglobin [Hb] <11 g/dL) in association with solid tumours, lymphoma or myeloma and eligible for biosimilar epoetin treatment were included. 99.9% of patients received epoetin zeta (median dose 30,000 IU/week). Mean baseline Hb was 9.61 g/dL, with 35.6% of patients having moderate anaemia (Hb 8–9.5 g/dL). Hb response was achieved in 81.6% and 86.5% of patients at 3 and 6 months, respectively. Overall mean change in Hb level was 1.52 ± 1.61 and 1.72 ± 1.61 g/dL at 3 and 6 months, respectively. Transfusion and thromboembolic event rates were 9.4% and 2.4% at 3 months, and 5.8% and 1.5% at 6 months, respectively.

Conclusions

Epoetin zeta was effective and well tolerated in the management of CIA in patients with solid tumours, lymphoma and myeloma.

Trial registration

Trial registration number: NCT02140736 (date of registration: 14 May 2014).

Hormones as doping in sports

Though we may still sing today, as did Pindar in his eighth Olympian Victory Ode, "… of no contest greater than Olympia, Mother of Games, gold-wreathed Olympia…", we must sadly admit that today, besides blatant over-commercialization, there is no more ominous threat to the Olympic games than doping. Drug-use methods are steadily becoming more sophisticated and ever harder to detect, increasingly demanding the use of complex analytical procedures of biotechnology and molecular medicine. Special emphasis is thus given to anabolic androgenic steroids, recombinant growth hormone and erythropoietin as well as to gene doping, the newly developed mode of hormones abuse which, for its detection, necessitates high-tech methodology but also multidisciplinary individual measures incorporating educational and psychological methods. In this Olympic year, the present review offers an update on the current technologically advanced endocrine methods of doping while outlining the latest procedures applied-including both the successes and pitfalls of proteomics and metabolomics-to detect doping while contributing to combating this scourge.

Anaemia management with C.E.R.A. in routine clinical practice: OCEANE (Cohorte Mircera patients non-dialyses), a national, multicenter, longitudinal, observational prospective study, in patients with chronic kidney disease not on dialysis

OBJECTIVE

The aim of this study was to describe the management of anaemia with a continuous erythropoietin receptor activator (C.E.R.A., methoxy polyethylene glycol epoetin-β), in patients with chronic kidney disease (CKD) not on dialysis, naïve or non-naïve to treatment with erythropoiesis-stimulating agents (ESAs) at inclusion.

DESIGN

National, multicentre, longitudinal, observational prospective study.

SETTING

133 nephrologists practicing in France selected patients during their routine follow-up visits. The study was non-interventional.

PARTICIPANTS

They were adult CKD patients not on dialysis or kidney transplant patients, naïve or not to ESA treatment: 524 patients not on dialysis (48% ESA-naïve) and 92 kidney transplant patients (24% ESA-naïve) were included and followed up every 3 months during 1 year.

OUTCOME MEASURES

The two main endpoints were the percentage of patients who achieved target haemoglobin (Hb) levels as per European Medicines Agency guidelines (10-12 g/dl) around 6 months of treatment and modalities of treatment.

RESULTS

Approximately one in two patients had an Hb level within 10-12 g/dl at baseline, and around 6 and 12 months of treatment. Ninety per cent of ESA-naïve patients achieved at least +1 g/dl increase over baseline Hb levels or had Hb within 10-12 g/dl around 6 and 12 months. The Hb level remained at approximately 11.5 g/dl during the 12 months of follow-up. Around 6 months: almost all patients were receiving a once-monthly subcutaneous dose of C.E.R.A. (patients not on dialysis: 95±54 µg; kidney transplant patients: 121±70 µg); approximately half the patients did not require a change in C.E.R.A. dose. Adverse effects related to C.E.R.A. were observed in less than 5% of patients and led to modification or discontinuation of treatment in 2%.

CONCLUSIONS

The efficacy and safety of C.E.R.A. in CKD patients not on dialysis, with or without kidney transplantation, were confirmed in routine clinical practice.

The waveform fluctuation and the clinical factors of the initial and sustained erythropoietic response to continuous erythropoietin receptor activator in hemodialysis patients

OBJECTIVES

Erythropoiesis-stimulating agents (ESA) are the main treatment for anemia in hemodialysis (HD) patients. We evaluated factors determining the response after treatment of a new ESA (continuous erythropoietin erythropoietin receptor activator (CERA)).

METHODS

61 HD patients were classified by their response at two different timings. First, patients whose hematocrit (Hct) increased 1.5% in the first week were defined as initial responders (IR, n = 16). We compared several parameters between IR and the rest of the study subjects (non-IR, n = 45). Second, patients whose Hct increased 2% in the 4th week were defined as sustained responders (SR, n = 12), and we did a similar comparison.

RESULTS

The Hct showed a waveform fluctuation. Compared with the rest, IR had significantly lower platelet counts and higher levels of ferritin, total protein, total bilirubin, and serum sodium, while SR had significantly lower levels of C-reactive protein and low-density lipoprotein (All P < 0.05). In comparison with the rest, higher Hct persisted for 10 weeks in SR but only for two separate weeks (the 1st and 7th week) in IR.

CONCLUSIONS

The initial and sustained erythropoietic responses are independent from each other and are associated with different factors. Treatment focusing on these factors may improve the response.

Erythropoietin use and abuse

Recombinant human erythropoietin (rhEPO) is arguably the most successful therapeutic application of recombinant DNA technology till date. It was isolated in 1977 and the gene decoded in 1985. Since then, it has found varied applications, especially in stimulating erythropoiesis in anemia due to chronic conditions like renal failure, myelodysplasia, infections like HIV, in prematurity, and in reducing peri-operative blood transfusions. The discovery of erythropoietin receptor (EPO-R) and its presence in non-erythroid cells has led to several areas of research. Various types of rhEPO are commercially available today with different dosage schedules and modes of delivery. Their efficacy in stimulating erythropoiesis is dose dependent and differs according to the patient's disease and nutritional status. EPO should be used carefully according to guidelines as unsolicited use can result in serious adverse effects. Because of its capacity to improve oxygenation, it has been abused by athletes participating in endurance sports and detecting this has proved to be a challenge.

Emerging technologies in the delivery of erythropoietin for therapeutics

Deciphering the function of proteins and their roles in signaling pathways is one of the main goals of biomedical research, especially from the perspective of uncovering pathways that may ultimately be exploited for therapeutic benefit. Over the last half century, a greatly expanded understanding of the biology of the glycoprotein hormone erythropoietin (Epo) has emerged from regulator of the circulating erythrocyte mass to a widely used therapeutic agent. Originally viewed as the renal hormone responsible for erythropoiesis, recent in vivo studies in animal models and clinical trials demonstrate that many other tissues locally produce Epo independent of its effects on red blood cell mass. Thus, not only its hematopoietic activity but also the recently discovered nonerythropoietic actions in addition to new drug delivery systems are being thoroughly investigated in order to fulfill the specific Epo release requirements for each therapeutic approach. The present review focuses on updating the information previously provided by similar reviews and recent experimental approaches are presented to describe the advances in Epo drug delivery achieved in the last few years and future perspectives.

[Anemia management in French hemodialysis patients: DiaNE study results at 3 years (DiaNE2)]

The observational study DiaNE provides a current state of anemia management with Epoetine bêta in hemodialysis patients regarding European recommendations over a 3-year period in France. Patients still treated with Epoetine bêta twelve months after their inclusion in DiaNE were eligible for a 24-month extension phase entitled DiaNE 2. Data regarding 439 patients followed during three years, from M0 to M36, were analyzed. Hemoglobin (Hb) level of the cohort remained over the target value of 11g/dL during the study (M0: 11.3±1.2g/dL; M36: 11.8±1.3g/dL). The anemia management had evolved with European recommendations updates and was in accordance with the last recommended target range (11-12g/dL) in a third of patients. During the follow-up, the majority of patients (97%) had at least one modification of treatment with Epoetine bêta (change in frequency of injections, adjustment of doses) mainly justified by excursion of Hb level out of the target range. However, the median dose of Epoetine bêta was relatively stable. The number of patients with iron treatment remained stable (60%). In spite of undertaken efforts, anemia management of hemodialysed patients in France still needs optimization for maintaining Hb level in the recommended target range.

Erythropoietin receptor response circuits

PURPOSE OF REVIEW

In 1985-1989, erythropoietin (EPO), its receptor (EPOR), and janus kinase 2 were cloned; established to be essential for definitive erythropoiesis; and initially intensely studied. Recently, new impetus, tools, and model systems have emerged to re-examine EPO/EPOR actions, and are addressed in this review. Impetus includes indications that EPO affects significantly more than standard erythroblast survival pathways, the development of novel erythropoiesis-stimulating agents, increasing evidence for EPO/EPOR cytoprotection of ischemically injured tissues, and potential EPO-mediated worsening of tumorigenesis.

RECENT FINDINGS

New findings are reviewed in four functional contexts: (pro)erythroblast survival mechanisms, new candidate EPO/EPOR effects on erythroid cell development and new EPOR responses, EPOR downmodulation and trafficking, and novel erythropoiesis-stimulating agents.

SUMMARY

As Current Opinion, this monograph seeks to summarize, and provoke, new EPO/EPOR action concepts. Specific problems addressed include: beyond (and before) BCL-XL, what key survival factors are deployed in early-stage proerythroblasts? Are distinct EPO/EPOR signals transduced in stage-selective fashions? Is erythroblast proliferation also modulated by EPO/EPOR signals? What functions are subserved by new noncanonical EPO/EPOR response factors (e.g. podocalyxin like-1, tribbles 3, reactive oxygen species, and nuclear factor kappa B)? What key regulators mediate EPOR inhibition and trafficking? And for emerging erythropoiesis-stimulating agents, to what extent do activities parallel EPOs (or differ in advantageous, potentially complicating ways, or both)?

Emerging PEGylated drugs

PEGylation is a pharmaceutical technology that involves the covalent attachment of polyethylene glycol (PEG) to a drug to improve its pharmacokinetic, pharmacodynamic, and immunological profiles, and thus, enhance its therapeutic effect. Currently, PEGylation is used to modify proteins, peptides, oligonucleotides, antibody fragments, and small organic molecules. Research groups are striving to improve the consistencies of PEGylated drugs and to PEGylate commercialized proteins and small organic molecules. Furthermore, the PEGylations of novel medications, like oligonucleotides and antibody fragments, are being pursued to improve their bioavailabilities. This active research in the PEGylation field and the continued growth of the biopharmaceutical market predicts that PEGylated drugs have a bright future.

CNTO 530 functions as a potent EPO mimetic via unique sustained effects on bone marrow proerythroblast pools

Anemia as associated with numerous clinical conditions can be debilitating, but frequently can be treated via administration of epoetin-alfa, darbepoietin-alfa, or methoxy-PEG epoetin-beta. Despite the complexity of EPO-EPO receptor interactions, the development of interesting EPO mimetic peptides (EMPs) also has been possible. CNTO 530 is one such novel MIMETIBODY Fc-domain dimeric EMP fusion protein. In a mouse model, single-dose CNTO 530 (unlike epoetin-alfa or darbepoietin-alfa) bolstered red cell production for up to 1 month. In 5-fluorouracil and carboplatin-paclitaxel models, CNTO 530 also protected against anemia with unique efficiency. These actions were not fully accounted for by half-life estimates, and CNTO 530 signaling events therefore were studied. Within primary bone marrow erythroblasts, kinetics of STAT5, ERK, and AKT activation were similar for CNTO 530 and epoetin-alfa. p70S6K activation by CNTO 530, however, was selectively sustained. In vivo, CNTO 530 uniquely stimulated the enhanced formation of PODXL(high)CD71(high) (pro)erythroblasts at frequencies multifold above epoetin-alfa or darbepoietin-alfa. CNTO 530 moreover supported the sustained expansion of a bone marrow-resident Kit(neg)CD71(high)Ter119(neg) progenitor pool. Based on these distinct erythropoietic and EPOR signaling properties, CNTO 530 holds excellent promise as a new EPO mimetic.

Current controversies in the management of the anemia of prematurity

Preterm infants, especially those with extremely low birth weight (ELBW) are exposed to frequent blood draws as part of their care in the neonatal intensive care unit. ELBW infants develop the anemia of prematurity (AOP), a hypo-proliferative anemia marked by inadequate production of erythropoietin (Epo). Treatment of AOP includes red blood cell transfusions, which are given to preterm infants based on indications and guidelines (hematocrit/hemoglobin levels, ventilation and oxygen need, apneas and bradycardias, poor weight gain) that are relatively non-specific. In this article we review recent studies evaluating transfusion guidelines, discuss ways to decrease phlebotomy losses and examine the use of red cell growth factors such as Epo in preventing and treating anemia in preterm infants.

Survival and proliferative roles of erythropoietin beyond the erythroid lineage

Since the isolation and purification of erythropoietin (EPO) in 1977, the essential role of EPO for mature red blood cell production has been well established. The cloning of the EPO gene and production of recombinant human EPO led to the widespread use of EPO in treating patients with anaemia. However, the biological activity of EPO is not restricted to regulation of erythropoiesis. EPO receptor (EPOR) expression is also found in endothelial, brain, cardiovascular and other tissues, although at levels considerably lower than that of erythroid progenitor cells. This review discusses the survival and proliferative activity of EPO that extends beyond erythroid progenitor cells. Loss of EpoR expression in mouse models provides evidence for the role of endogenous EPO signalling in nonhaematopoietic tissue during development or for tissue maintenance and/or repair. Determining the extent and distribution of receptor expression provides insights into the potential protective activity of EPO in brain, heart and other nonhaematopoietic tissues.