Long-acting erythropoietin: clinical studies and potential uses in neonates

Early versus late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

OBJECTIVES

To assess the effectiveness and safety of early versus late initiation of EPO in reducing red blood cell (RBC) transfusions in preterm and/or low birth weight (LBW) infants.

SEARCH METHODS

The standard search of the Cochrane Neonatal Review Group (CNRG) was performed in 2006 and updated in 2009. Updated search in September 2009 as follows: The Cochrane Library, MEDLINE (search via PubMed), CINAHL and EMBASE were searched from 2005 to September 2009. The searches were repeated in March 2012. The Pediatric Academic Societies' Annual meetings were searched electronically from 2000 to 2012 at Abstracts2View^TM as were clinical trials registries (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials enrolling preterm or LBW infants less than eight days of age.

INTERVENTION

Early initiation of EPO (initiated at less than eight days of age) versus late initiation of EPO (initiated at eight to 28 days of age).

DATA COLLECTION AND ANALYSIS

The standard methods of the CNRG were followed. Weighted treatment effects included typical risk ratio (RR), typical risk difference (RD), number needed to treat to benefit (NNTB), number needed to treat to harm (NNTH) and mean difference (MD), all with 95% confidence intervals (CI). A fixed-effect model was used for meta-analyses and heterogeneity was evaluated using the I-squared (I²) test.

MAIN RESULTS

No new trials were identified in March of 2012. Two high quality randomised double-blind controlled studies enrolling 262 infants were identified. A non-significant reduction in the 'Use of one or more RBC transfusions' [two studies 262 infants; typical RR 0.91 (95% CI 0.78 to 1.06); typical RD -0.07 (95% CI -0.18 to 0.04; I² = 0% for both RR and RD] favouring early EPO was noted. Early EPO administration resulted in a non-significant reduction in the "number of transfusions per infant" compared with late EPO [typical MD - 0.32 (95% CI -0.92 to 0.29)]. There was no significant reduction in total volume of blood transfused per infant or in the number of donors to whom the infant was exposed. Early EPO led to a significant increase in the risk of retinopathy of prematurity (ROP) (all stages) [two studies, 191 infants; typical RR 1.40 (95% CI 1.05 to 1.86); typical RD 0.16 (95% CI 0.03 to 0.29); NNTH 6 (95% CI 3 to 33)]. There was high heterogeneity for this outcome (I² = 86% for RR and 81% for RD). Both studies (191 infants) reported on ROP stage > 3. No statistically significant increase in risk was noted [typical RR 1.56 (95% CI 0.71 to 3.41); typical RD 0.05 (-0.04 to 0.14)] There was no heterogeneity for this outcome (0% for both RR and RD). No other important favourable or adverse neonatal outcomes or side effects were reported.

AUTHORS' CONCLUSIONS

The use of early EPO did not significantly reduce the 'Use of one or more RBC transfusions' or the 'Number of transfusions per infant" compared with late EPO administration. The finding of a statistically significant increased risk of ROP (any grade) and a similar trend for ROP stage > 3 with early EPO treatment is of great concern.

Darbepoetin Administration in Term and Preterm Neonates

Erythropoiesis-stimulating agents (ESAs) such as erythropoietin have been studied as red cell growth factors in preterm and term infants for more than 20 years. Recent studies have evaluated darbepoetin (Darbe, a long-acting ESA) for both erythropoietic effects and potential neuroprotection. We review clinical trials of Darbe in term and preterm infants, which have reported significant erythropoietic uses and neuroprotective effects. ESAs show great promise in decreasing or eliminating transfusions, and in preventing and treating brain injury in term and preterm infants.

Early versus late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

OBJECTIVES

To assess the effectiveness and safety of early versus late initiation of EPO in reducing red blood cell (RBC) transfusions in preterm and/or low birth weight (LBW) infants.

SEARCH METHODS

The standard search of the Cochrane Neonatal Review Group (CNRG) was performed in 2006 and updated in 2009. Updated search in September 2009 as follows: The Cochrane Library, MEDLINE (search via PubMed), CINAHL and EMBASE were searched from 2005 to September 2009. The searches were repeated in March 2012. The Pediatric Academic Societies' Annual meetings were searched electronically from 2000 to 2012 at Abstracts2View(TM) as were clinical trials registries (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials enrolling preterm or LBW infants less than eight days of age.

INTERVENTION

Early initiation of EPO (initiated at less than eight days of age) versus late initiation of EPO (initiated at eight to 28 days of age).

DATA COLLECTION AND ANALYSIS

The standard methods of the CNRG were followed. Weighted treatment effects included typical risk ratio (RR), typical risk difference (RD), number needed to treat to benefit (NNTB), number needed to treat to harm (NNTH) and mean difference (MD), all with 95% confidence intervals (CI). A fixed-effect model was used for meta-analyses and heterogeneity was evaluated using the I-squared (I(2)) test.

MAIN RESULTS

No new trials were identified in March of 2012. Two high quality randomised double-blind controlled studies enrolling 262 infants were identified. A non-significant reduction in the 'Use of one or more RBC transfusions' [two studies 262 infants; typical RR 0.91 (95% CI 0.78 to 1.06); typical RD -0.07 (95% CI -0.18 to 0.04; I(2) = 0% for both RR and RD] favouring early EPO was noted. Early EPO administration resulted in a non-significant reduction in the "number of transfusions per infant" compared with late EPO [typical MD - 0.32 (95% CI -0.92 to 0.29)]. There was no significant reduction in total volume of blood transfused per infant or in the number of donors to whom the infant was exposed. Early EPO led to a significant increase in the risk of retinopathy of prematurity (ROP) (all stages) [two studies, 191 infants; typical RR 1.40 (95% CI 1.05 to 1.86); typical RD 0.16 (95% CI 0.03 to 0.29); NNTH 6 (95% CI 3 to 33)]. There was high heterogeneity for this outcome (I(2) = 86% for RR and 81% for RD). Both studies (191 infants) reported on ROP stage ≥ 3. No statistically significant increase in risk was noted [typical RR 1.56 (95% CI 0.71 to 3.41); typical RD 0.05 (-0.04 to 0.14)] There was no heterogeneity for this outcome (0% for both RR and RD). No other important favourable or adverse neonatal outcomes or side effects were reported.

AUTHORS' CONCLUSIONS

The use of early EPO did not significantly reduce the 'Use of one or more RBC transfusions' or the 'Number of transfusions per infant" compared with late EPO administration. The finding of a statistically significant increased risk of ROP (any grade) and a similar trend for ROP stage ≥ 3 with early EPO treatment is of great concern.

Hematological interventions in NICU care: the use of rEpo, IVIG, and rG-CSF

This article focuses on the use of rEpo, IVIG, and rG-CSF in the NICU. It discusses the most recent studies and the most definitive and clinically relevant evidence, rather than summarizing all published studies. The last section was written for NICU practice groups that choose to use any of these medications and are seeking a consistent approach for doing so. The section provides the author's approach to the use of rEpo, IVIG, and rG-CSF, revealing personal preferences, interpretations, and experiences, and is based on the dictum, "if you are going to use it, use it the same way each time."

Darbepoetin alfa exerts a cardioprotective effect in autoimmune cardiomyopathy via reduction of ER stress and activation of the PI3K/Akt and STAT3 pathways

Dilated human cardiomyopathy is associated with suppression of the prosurvival phosphatidylinositol-3-kinase (PI3K)/Akt and STAT3 pathways. The present study was carried out to determine if restoration of the PI3K/Akt and STAT3 activity by darbepoetin alfa improved cardiac function or reduced cardiomyocyte apoptosis in rabbit autoimmune cardiomyopathy induced by a peptide corresponding to the second extracellular loop of the ss(1)-adrenergic receptor (ss(1)-EC(II)). We found that ss(1)-EC(II) immunization produced progressive LV dilation, systolic dysfunction and myocyte apoptosis as measured by TUNEL, single-stranded DNA antibody, and active caspase-3. These changes were associated with activation of p38 mitogen-activated protein kinase (MAPK), endoplasmic reticulum stress markers (GRP78 and CHOP), and increased cleavage of procaspase-12, as well as decreased phosphorylation of Akt and STAT3, and decreased Bcl2/Bax ratio. As expected, darbepoetin alfa treatment increased phosphorylation of Akt and STAT3. It also increased the myocardial expression of erythropoietin receptor which was reduced in the failing myocardium, and improved cardiac function in the ss(1)-EC(II)-immunized animals. The latter was associated with reductions of myocyte apoptosis and cleaved caspase-3, as well as reversal of increased phosphorylation of p38-MAPK, increased ER stress, and decline in Bcl2/Bax ratio. The anti-apoptotic effects of darbepoetin alfa via Akt and STAT activation were also demonstrated in cultured cardiomyocytes treated with the anti-ss(1)-EC(II) antibody. These effects of darbepoetin alfa in vitro were prevented by LY294002 and STAT3 peptide inhibitor. Thus, we conclude that darbepoetin alfa improves cardiac function and prevents progression of dilated cardiomyopathy probably by activating the PI3K/Akt and STAT3 pathways and reducing ER stress.

Epo and other hematopoietic factors

The growth factors erythropoietin and granulocyte-colony stimulating factor have hematopoietic and non-hematopoietic functions. Both are used clinically in their recombinant forms. Both also have interesting tissue-protective effects in other organs, which are unrelated to their hematopoietic functions. They have clinical hematopoietic uses in neonatal populations and in experimental non-hematopoietic research, and clinical potential as neuroprotective or tissue-protective agents.

Early versus late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Hematocrit falls after birth in preterm infants due to physiological factors and frequent blood letting. Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

OBJECTIVES

To assess the effectiveness and safety of early (before 8 days after birth) versus late (between 8 - 28 days after birth) initiation of EPO in reducing red blood cell transfusions in preterm and/or low birth weight infants.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006) was searched. Electronic and manual searches were conducted in November 2005 of MEDLINE, EMBASE and CINAHL, personal files, bibliographies of identified trials and abstracts by the Pediatric Academic Societies' and the European Society of Pediatric Research Meetings published in Pediatric Research.

DESIGN

Randomized or quasi-randomized controlled trials.

POPULATION

Preterm (< 37 weeks gestational age) or low birth weight infants (< 2500 g) less than eight days of age.

INTERVENTION

Early initiation of EPO (initiated at < 8 days of age) vs. late initiation of EPO (initiated at 8 - 28 days of age). Outcomes; At least one of the following outcomes were reported: Use of one or more red blood cell transfusions; Total volume (ml/kg) of blood transfused per infant; Number of transfusions per infant; Number of donors to whom the infant was exposed; Mortality during initial hospital stay (all causes); and common outcomes associated with preterm birth.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group were followed independently by the authors to assess study quality and report outcomes. Weighted treatment effects, calculated using RevMan 4.2.8 included typical relative risk (RR), typical risk difference (RD), number needed to treat to benefit (NNTB), number needed to treat to harm (NNTH) and mean difference (MD), all with 95% confidence intervals (CI). A fixed effect model was used for meta-analyses. Heterogeneity tests including the I-squared (I(2)) test were performed to assess the appropriateness of pooling the data.

MAIN RESULTS

Two high quality randomized double-blind controlled studies enrolling 262 infants were identified (Donato 2000; Maier 2002). Both studies used well defined, but not identical, criteria for blood transfusions. Between 14 and 32% of the enrolled infants had received blood transfusions prior to study entry. A non-significant reduction in the 'use one or more red blood cell transfusions' [typical RR 0.91 (95% CI 0.78, 1.06); typical RD - 0.07 (95% CI -0.18, 0.04)] favouring early EPO was noted. Both studies (n = 262) reported on "number of transfusions per infant"; early EPO administration resulted in a non-significant reduction compared to late EPO [typical WMD - 0.32 (95% CI -0.92, 0.29)]. There was no significant reduction in total volume of blood transfused per infant or in the number of donors to whom the infant was exposed. Retinopathy of prematurity (ROP) (all stages) was assessed in 191 infants. Early EPO led to a significant increase in the risk of ROP [(typical RR 1.40 (95% CI 1.05, 1.86); typical RD 0.16 (95% CI 0.03, 0.29); NNTH 6 (95% CI 3 -33)]. There was statistically significant heterogeneity for this outcome. Both studies (n = 191) reported on ROP stage > 3. No statistically significant increase in risk was noted [typical RR 1.56 (95% CI 0.71, 3.41); typical RD was 0.05 (95% CI - 0.04, 0.14)]. There was no statistically significant heterogeneity for this outcome for either RR or for RD. No other important favourable or adverse neonatal outcomes or side effects were reported.

AUTHORS' CONCLUSIONS

The use of early EPO did not significantly reduce the primary outcome of "use of one or more red blood cell transfusions", or "number of transfusions per infant" compared to late EPO administration. Currently there is lack of evidence that early EPO vs. late EPO confers any substantial benefits with regard to any donor blood exposure as a large proportion (14 - 30 %) of infants enrolled in these studies were exposed to donor blood prior to study entry. The finding of a statistically significant increased risk of ROP (any grade) and a similar trend for ROP stage > 3 with early EPO treatment is of great concern. No further studies comparing early vs. late administration of EPO are warranted.

Erythropoietin and prematurity--where do we stand?

Erythropoietin (EPO) treatment for anemia of prematurity is still controversial. Large multicentric trials demonstrate that administration of EPO+Fe cannot prevent early transfusions, particularly in very low birth weight newborns and in infants with severe neonatal diseases, but may have some beneficial effect to prevent late transfusions. Current treatment of anemia of prematurity should be multifactorial trying to minimize all causes that reduce erthrocytic mass (phlebotomies, use of noninvasive procedures) and promoting all factors that increase it (placental transfusion, adequate nutrition support). To evaluate the real impact of EPO treatment it is mandatory to follow similar transfusion protocols for preterm infants in all the studies. The aim of EPO+Fe administration should be to avoid new late transfusions in very low birth weight preterm infants or to prevent the first transfusion after the second week of life in less immature premature with the objective of reducing the number of donors rather than the number of transfusions. We have limited the use of EPO+Fe to infants <30 weeks gestational age and birth weight <or=1250 g as well as to infants weighing 1250-1500 g with initial severe disease. The comparison of outcomes before (28 months period with EPO+Fe treatment to all premature <or=32 weeks gestational age) and after 20 months of implementation of the new protocol showed a significant decrease in EPO+Fe treatment candidates (40.3% vs. 85.9%, P<0.001) without changes in the percentage of transfusions in both periods. Therefore if EPO treatment is to be given it should be limited to preterm infants with a birth weight <1000 g or those of 1000-1250 g associated with risk factors for blood transfusion. It should be started at 3-7 days of life at doses of 250 U/kg subcutaneously, three times a week, for 4-6 weeks depending on gestational age with oral iron 2-12 mg/kg/day to keep ferritin levels greater than 100 ng/mL.

Single-dose darbepoetin administration to anemic preterm neonates

OBJECTIVE

Darbepoetin is longer acting and more potent than recombinant erythropoietin (rEpo). In certain situations, preterm neonates might benefit from rEpo, and for such patients darbepoetin would require fewer doses at a lower cost. However, the proper dose and dosing interval have not been established.

STUDY DESIGN

We performed a prospective trial in two level III Neonatal Intensive Care Units. Patients <32 weeks gestation at birth, with a birth weight (BW) <1500 g, were eligible for participation if they were >21-days-old and had a hemoglobin (Hgb) concentration </or=10.5 g/dl. In all, 12 were to receive a single subcutaneous (s.c.) dose at either 1 or 4 microg/kg. Once before the dose was given, and at two preset intervals after, blood was obtained for immature reticulocyte fraction (IRF) and absolute reticulocyte count (ARC). Once before and at four preset intervals after, blood was obtained for pharmacokinetic studies.

RESULTS

The 12 subjects had BWs of 1129+/-245 g (mean+/-SD), were 29.2+/-1.2 weeks gestation at delivery, and were 43+/-12 days old with an Hgb concentration of 9.6+/-1.0 g/dl when the darbepoetin was given. Six received 1 microg/kg and six 4 microg/kg. The IRF increased (p<0.05) as did the ARC (p<0.05). The increases in IRF were somewhat greater among the 4 microg/kg recipients (P=0.06). The highest recorded concentrations of drug occurred 6 to 12 hours after administration. The combined 6 and 12 hours values were 185+/-106 mU/ml in the 1 microg/kg group vs 597+/-238 in the 4 microg/kg group (p<0.002). The t(1/2) was 26 hours (range 10 to 50). The biovailability-normalized clearance was 19 ml/hour/kg (range 5 to 54).

CONCLUSIONS

A single s.c. dose of darbepoetin given to preterm neonates accelerated effective erythropoiesis. The pharmacodynamic and pharmacokinetic findings suggest that darbepoetin dosing in neonates would require a higher unit dose/kg and a shorter dosing interval than are generally used for anemic adults.