Erythropoietin combined with traditional Chinese medicine for chemotherapy-induced anemias: A protocol of systematic review and meta-analysis

BACKGROUND

As far as we know, several systematic review and meta-analysis have assessed the safety and efficacy of erythropoiesis-stimulating agents (ESAs) in the patients with chemotherapy-induced anemia (CIA). But no study assesses the safety and efficacy of ESAs combined with traditional Chinese medicine (TCM). The aim of our study is to assess the efficacy and safety of ESAs combination with TCM for patients with CIA and will provide a higher level of evidence for clinical applications.

METHODS

This protocol adheres to the preferred reporting items for systematic reviews and meta-analysis protocol statement. The source of literature will be a structured search of the following 7 electronic databases: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, and Wanfang Database. Records will be independently evaluated by 2 reviewers. Disagreements will be resolved through consensus or third-party adjudication. Review Manager 5.3 software (Cochrane Collaboration, Copenhagen Denmark) will be used to perform meta-analysis. For dichotomous variables, odds ratio with 95% confidence intervals will be obtained by the Mantel-Haenszel method. For continuous data, mean difference with 95% confidence intervals will be used. P < 0.05 will be considered to be statistically significant.

RESULTS

This study will be performed to test the efficacy and safety of ESAs combined with TCM for CIA in patients with cancer.

CONCLUSIONS

The result of this study will be promoted mainly in 2 ways: publish in peer-reviewed journals in the fastest way; and promotion in domestic and foreign conferences.

INPLASY REGISTRATION NUMBER

INPLASY202080041.

Efficacy and safety of erythropoietin in patients with traumatic brain injury: A systematic review and meta-analysis

OBJECTIVE

The purpose of this study was to evaluate the effects of erythropoietin (EPO) on mortality and neurological outcomes in patients with traumatic brain injury (TBI).

MATERIALS AND METHODS

Electronic databases of studies published up to January 5, 2017 were searched to retrieve relevant investigations comparing the outcomes of EPO-treated patients and untreated patients following TBI. We calculated the relative risk (RR) of mortality, neurologic outcomes, and deep vein thrombosis (DVT) with corresponding 95% confidence interval (CI) using meta-analysis.

RESULTS

Six randomized controlled clinical trials met the eligibility criteria. In total, 1041 patients were included among the studies. EPO was found to significantly reduce the occurrence of mortality (RR 0.68 [95% CI 0.50-0.95]; P = 0.02), but did not significantly reduce poor functional outcome (RR 1.22 [95% CI 0.82-1.81]; P = 0.33). There were no significant differences in the occurrence of complications, such as DVT, between the treatment groups (RR -0.02 [95% CI -0.06-0.02]; P = 0.81).

CONCLUSIONS

Results of the present meta-analysis suggest that the use of EPO may prevent death following TBI without causing adverse events, such as deep vein thrombosis. However, the role of EPO in improving neurological outcome(s) remains unclear. Further well-designed, randomized controlled trials using modified protocols and involving specific patient populations are required to clarify this issue, and to verify the findings.

Collaborative study for the establishment of erythropoietin BRP batch 5

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for erythropoietin (EPO) is used as a working standard for potency determination of EPO preparations by in vivo bioassay as prescribed in Ph. Eur. monograph 1316 'Erythropoietin concentrated solution'. BRP batch 4 (BRP4) was calibrated in 2014 and its stocks are depleted. The European Directorate for the Quality of Medicines and HealthCare (EDQM) thus endorsed a project (BSP147) to calibrate a replacement batch in International Units against the 3rd WHO International Standard (IS) for erythropoietin, recombinant, for bioassay (11/170). The amount of material contained in the vial of BRP4 greatly exceeded the amount needed for one bioassay, sometimes leading to considerable waste. It was thus decided to prepare a candidate material with a lower EPO content. The collaborative study involved eight laboratories in Europe, the USA and Australia. Based on the outcome of the study, the Ph. Eur. Commission adopted the proposed standard as Erythropoietin BRP batch 5 in June 2018 for use as a reference preparation solely for the polycythaemic and normocythaemic mouse bioassays, with an assigned potency of 2000 IU/ampoule. Furthermore, the potency of BRP batch 4 was confirmed during the study thus warranting a good continuity of the International Unit.

Establishment of the Ph. Eur. erythropoietin chemical reference substance batch 1

The Erythropoietin (EPO) European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) batch 3 was calibrated in 2006 by in vivo bioassay and was used as a reference preparation for these assays as well as for the physicochemical methods in the Ph. Eur. monograph Erythropoietin concentrated solution (1316). In order to avoid the frequent replacement of this standard and thus reduce the use of animals, a new EPO Chemical Reference Substance (CRS) was established to be used solely for the physicochemical methods. Here we report the outcome of a collaborative study aimed at demonstrating the suitability of the candidate CRS (cCRS) as a reference for the physicochemical methods in the Ph. Eur. monograph. Results from the study demonstrated that for the physicochemical methods currently required in the monograph (capillary zone electrophoresis (CZE), polyacrylamide gel electrophoresis (PAGE)/immunoblotting and peptide mapping), the cCRS is essentially identical to the existing BRP. However, data also indicated that, for the physicochemical methods under consideration for inclusion in a revised monograph (test for oxidised forms and glycan mapping), the suitability of the cCRS as a reference needs to be confirmed with additional work. Further to completion of the study, the Ph. Eur. Commission adopted the cCRS as "Erythropoietin for physicochemical tests CRS batch 1" to be used for CZE, PAGE/immunoblotting and peptide mapping.

Collaborative study for the establishment of erythropoietin BRP batch 4

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for erythropoietin (EPO) is used as a working standard for potency determination of EPO preparations by in vivo bioassay as prescribed in the Ph. Eur. monograph Erythropoietin concentrated solution (1316). The BRP batch 3 was calibrated in 2006 and its stocks are depleted. The European Directorate for the Quality of Medicines & HealthCare (EDQM) thus initiated a project to calibrate a replacement batch in International Units against the WHO 3(rd) International Standard (IS) for Erythropoietin, recombinant, for bioassay (11/170). A Ph. Eur. Chemical Reference Substance (CRS) was established recently for use as reference in some of the physicochemical tests prescribed in the monograph. Therefore, the EPO BRP batch 4 was only calibrated for the normocythaemic and polycythaemic mouse in vivo bioassays described in the Assay section of the Ph. Eur. monograph (1316). The collaborative study involved seven laboratories from Europe, the USA and South America. The results confirmed that the candidate BRP (cBRP) is suitable for use as a reference preparation in the potency determination of EPO medicinal products by bioassay (using the normocythaemic or polycythaemic mouse methods). The outcome of the study enabled the Ph. Eur. Commission to establish the proposed standard as erythropoietin BRP batch 4 in November 2014 for use as a reference preparation solely for the polycythaemic and normocythaemic mouse bioassay, with an assigned potency of 13 000 IU/vial. Furthermore, the potency of BRP3 was confirmed during the study, thus warranting a good continuity of the IU.

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.

Collaborative study for the establishment of erythropoietin BRP batch 3

The European Pharmacopoeia (Ph. Eur.) monograph on Erythropoietin concentrated solution (1316) specifies that identification and assay are performed using pharmacopoeial methods requiring the use of a reference preparation. To replace the current erythropoietin Biological Reference Preparation (BRP) of Ph. Eur., in 2006, the European Directorate for the Quality of Medicines undertook a collaborative study designed to establish a replacement batch. In order to guarantee continuity, the formulation of the candidate batch was similar to that of previous batches (1 and 2). The methods chosen to qualify the new standard were those included in the current monograph. The study was defined to allow calibration of the candidate by in vivo bioassay in terms of the current World Health Organization (WHO) International Standard (IS) and to assign a unitage. The suitability of the candidate preparation to serve as a reference standard for the other pharmacopoeial analytical procedures was also investigated. The collaborative study involved 16 laboratories from Europe, Australia, Canada, China, Japan, South Korea and the United States of America. Participants carried out biological and physicochemical assays on the candidate erythropoietin BRP batch 3 (cBRP3), using batch 2 (BRP2) and where necessary the 2nd World Health Organization International Standard (WHO 2nd IS) for recombinant erythropoietin as the reference standards. It was demonstrated that the replacement batch is appropriate for use as erythropoietin BRP in the context of the control of erythropoietin concentrated solutions according to the Ph. Eur. monograph (1316). However as regards the potency of BRP2 and cBRP3 in the mouse bioassay unexpected observations were made. Direct calibration of BRP2 against the WHO 2nd IS yielded, in all laboratories, results that were systematically higher than the potency of 32,500 IU/vial assigned by direct calibration against the WHO 2nd IS in the former study. It was therefore recommended to assign the potency of cBRP3 against BRP2, using the average of all results that were not considered as outlying obtained in the collaborative study, in order to guarantee continuity of unitage between the successive BRP batches. The outcome of the study enabled the Ph. Eur. Commission to establish the proposed standard as 'erythropoeitin BRP batch 3' (BRP3). BRP3 was established in June 2007 for use as a reference preparation for the polycythaemic and normocythaemic mouse bioassay, with an assigned potency of 35,280 IU/vial, the identification by capillary zone electrophoresis, by polyacrylamide gel electrophoresis, immunoblotting and peptide mapping and as a reference for checking the system suitability of size-exclusion chromatographic procedures used in the test for dimers and related substances of higher molecular mass in the Ph. Eur. monograph (1316).

Effect of preprinted order form on epoetin alfa prescribing

PURPOSE

The effect of a required preprinted order form on the prescribing of epoetin alfa was evaluated.

SUMMARY

An initial drug-use evaluation (DUE) was conducted in January 2004 to determine how closely prescribing guidelines for epoetin alfa were being followed. A preprinted order form was then developed and approved by the medical staff, with use required for all adult epoetin alfa orders. A follow-up DUE was conducted in January 2006 to assess the effects of the preprinted order form on prescribing patterns. Expenditures for epoetin alfa for 12 months before and after implementation of the preprinted order form were also calculated. Data for 45 and 44 patients were reviewed for the initial and follow-up DUEs, respectively. Smaller doses were ordered at more frequent intervals and epoetin alfa was prescribed more often by nephrologists and less frequently by surgeons and critical care intensivists after implementation of the preprinted order form. Use of epoetin alfa according to hospital guidelines improved from 44% to 73% (p = 0.0089). Significantly more patients' ferritin and transferrin saturation values were measured postimplementation of the order form (p = 0.0176). In addition, the annual expense for epoetin alfa was reduced by $151,042, a 36% reduction from baseline.

CONCLUSION

Implementation of a required preprinted order form increased the frequency of appropriate prescribing of epoetin alfa in a community teaching hospital.

Erythropoietin Safety and Efficacy in Chronic Allograft Nephropathy

BACKGROUND

Patients with chronic allograft nephropathy (CAN) very frequently suffer anemia. Correction of anemia by means of recombinant erythropoietin (rEpo) is possible and useful, but safety and efficacy must be assessed.

METHODS

This multicenter, prospective, open study included patients with a cadaver renal transplant, CAN, and non-ferropenic anemia. The aim of the study was to determine the safety and efficacy of treatment with rEpo to target hematocrit (HCT) values around 35% and/or hemoglobin (Hb) levels of 11 g/dL.

RESULTS

Twenty-four patients were included: 71% males and 29% females aged 49.5 +/- 14 years. At last follow-up, 48% did not show anemia-related symptoms, and 19% experienced adverse events possibly or probably related to rEpo. In 86% of cases, anemia was corrected and in 71%, graft survival was conserved. Patients whose anemia was not corrected had poor initial renal function (sCr 5 +/- 1 mg/dL vs sCr 3.2 +/- 1 mg/dL, P = .028). Patients with graft survival showed correction of anemia (P = .001) on a relatively low dose of rEpo and without a significant increase in blood pressure.

CONCLUSIONS

All patients who had graft survival and only half of those who lost their graft showed a correction of anemia. The rEpo treatment neither accelerated nor decelerated renal failure. The difference between patients in whom anemia was corrected, or not, did not depend upon the previous level of HCT/Hb, but upon worse renal function. Thus, rEpo in patients with CAN is safe and effective, so administration should be initiated early to avoid adverse events deriving from anemia.

The FDA's assessment of follow-on protein products: a historical perspective

The scientific and regulatory issues that are associated with the possible introduction of 'follow-on' versions of protein drug products are the topic of considerable debate at present. Because of the differences between protein drug products and small-molecule drugs, the development of follow-on versions of protein products presents more complex scientific challenges than those presented by the development of generic versions of small-molecule drugs. Here, with a view to illustrating the Food and Drug Administration's (FDA's) scientific reasoning and experience in this area, we discuss past examples of the FDA's actions involving the evaluation of various types of follow-on and second-generation protein products and within-product manufacturing changes. The FDA believes its evaluation of the safety and effectiveness of follow-on protein products will evolve as scientific and technological advances in product characterization and manufacturing continue to reduce some of the complexity and uncertainty that are inherent in the manufacturing of protein products.

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.

Comparison of epoetin alfa and darbepoetin alfa biological activity under different administration schedules in normal mice

The unit of erythropoietic activity has long been the standard by which erythropoietic agents are judged, but the development of long-acting agents such as darbepoetin alfa has highlighted the shortcomings of this approach. To this point, we compared the in vivo activity of Epoetin alfa and darbepoetin alfa per microgram of protein core. Using the established mass-to-unit conversion for Epoetin alfa (1 microg congruent with 200 U), we then calculated darbepoetin alfa activity in units. Activity varied with treatment regimen (1 microg darbepoetin alfa congruent with 800 U for 3 times weekly dosing to 8,000 U for a single injection). This analysis reveals the inadequacy of evaluating darbepoetin alfa activity in terms of standard erythropoietic units. We therefore propose that for molecules with heightened biological activity, a more legitimate basis for comparison is the protein mass.

Reviews: Should the Target Hemoglobin for Patients with Chronic Kidney Disease Treated with Erythropoietic Replacement Therapy be Changed?

Recombinant human erythropoietin (rHuEPO, epoetin) revolutionized the treatment of anemia in patients with chronic kidney disease (CKD) when it was approved for use in the United States in 1989. Among dialysis patients, the mean hemoglobin (Hb) in patients undergoing dialysis rose from 7-8 g/dl prior to 1989 to 11-12 g/dl today. Among patients with CKD not on dialysis, epoetin use has not been as broadly applied as among dialysis patients, and although the mean Hb level in this patient population has increased, the impact has been less than in patients on dialysis. The optimal treatment target for epoetin remains controversial. Consistent with clinical practice guidelines, current practice in dialysis patients in the United States aims to maintain a target Hb of 11-12 g/dl, a level that is still well below the normal range. Debate centers on whether the current Hb target is too low and whether the target range is too narrow. Quality of life clearly improves in many individuals as Hb rises into the normal range from lower levels. In retrospective studies, higher Hb levels have been associated with lower risks of hospitalization and mortality. However, one large, prospective clinical trial has raised concern about normalizing Hb in hemodialysis patients with cardiac disease, and other prospective studies have not yet provided convincing evidence of significant benefits from normalizing Hb in dialysis-dependent and non-dialysis-dependent patients with CKD. A relative lack of information on non-dialysis-dependent patients with CKD and changes in fiscal policies regulating reimbursement for epoetin have contributed to uncertainty as to the best practices for anemia management in patients with CKD. There is increasing interest in the potential benefits of broadening the current target Hb range or eliminating an upper limit altogether and instead establishing a minimum Hb goal. While some extension of the upper limit of the currently recommended target Hb range might appear to be reasonable, the extent to which this should be extended, the benefits, risks, and costs of maintaining higher Hb levels in patients with CKD, and whether target Hb levels should be different in different CKD patient groups remains to be determined. Future efforts are likely to focus on selecting patient populations most likely to benefit from normalizing Hb, while adjusting the range of a subnormal Hb target for others.

Collaborative study for the establishment of erythropoietin BRP batch 2

The preparation and establishment of the 2nd European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for erythropoietin was the goal of a project run within the framework of the European Biological Standardisation Programme. The project, coded BSP062, was carried out between October 2002 and July 2003. The candidate preparation (cBRP2) was prepared in a similar manner to the first BRP batch (BRP1), as follows: -50:50 (weight/weight) blending of the two erythropoietin preparations currently available on the European market (epoietin-alpha and epoietin-beta), -lyophilisation using a protein-free carrier formulation to allow use of the standard for both biological and physico-chemical assay methods, -each vial contains approximately 250 microg erythropoietin. The cBRP2 was analysed in a collaborative study, carried out with the following aims: -to calibrate cBRP2 by in vivo bioassay in terms of the International Standard for erythropoietin, and assign a unitage, -to demonstrate continuity of unitage with BRP1, -to evaluate the suitability of cBRP2 to serve as a reference material for physico-chemical tests of erythropoietin. The collaborative study involved 14 laboratories both from Europe, and from Australia, Canada, South-Korea and the United States of America. Participants carried out biological and physicochemical assays on the candidate BRP batch 2, using BRP 1 and the 2nd World Health Organization (WHO) International Standard (IS) for recombinant erythropoietin as the reference standards. It was demonstrated that: -an assigned potency of 32,500 U per vial would maintain continuity between BRP1 and BRP2 in terms of the IS for erythropoietin, -the replacement batch was appropriate for use as erythropoietin BRP in the context of the control of erythropoietin concentrated solutions according to the Ph. Eur. monograph 1316. In July 2003, the Ph. Eur. Commission established the proposed standard as 'Erythropoeitin BRP batch 2' for use as a reference preparation for the polycythaemic and normocythaemic mouse bioassay, with an assigned potency of 32,500 U/vial, the identification by capillary zone electrophoresis (CZE), by polyacrylamide gel electrophoresis, immunoblotting and peptide mapping and as a reference for checking the system suitability of size exclusion chromatographic procedures used in the test for 'Dimers and related substances of higher molecular mass'.

Biological evaluation of recombinant human erythropoietin in pharmaceutical products

The potencies of mammalian cell-derived recombinant human erythropoietin pharmaceutical preparations, from a total of five manufacturers, were assessed by in vivo bioassay using standardized protocols. Eight-week-old normocythemic mice received a single subcutaneous injection followed by blood sampling 96 h later or multiple daily injections with blood sampling 24 h after the last injection. Reticulocyte counting by microscopic examination was employed as the end-point using the brilliant cresyl blue or selective hemolysis methods, together with automated flow cytometry. Different injection schedules were investigated and dose-response curves for the European Pharmacopoeia Biological Reference Preparation of erythropoietin were compared. Manual and automated methods of reticulocyte counting were correlated with respect to assay validity and precision. Using 8 mice per treatment group, intra-assay precision determined for all of the assays in the study showed coefficients of variation of 12.1-28.4% for the brilliant cresyl blue method, 14.1-30.8% for the selective hemolysis method and 8.5-19.7% for the flow cytometry method. Applying the single injection protocol, a combination of at least two independent assays was required to achieve the precision potency and confidence limits indicated by the manufacturers, while the multiple daily injection protocol yielded the same acceptable results within a single assay. Although the latter protocol using flow cytometry for reticulocyte counting gave more precise and reproducible results (intra-assay coefficients of variation: 5.9-14.2%), the well-characterized manual methods provide equally valid alternatives for the quality control of recombinant human erythropoietin therapeutic products.

Glycosylation of erythropoietin affects receptor binding kinetics: role of electrostatic interactions

Erythropoietin (EPO) is a cytokine produced by the kidney whose function is to stimulate red blood cell production in the bone marrow. Previously, it was shown that the affinity of EPO for its receptor, EPOR, is inversely related to the sialylation of EPO carbohydrate. To better understand the properties of EPO that modulate its receptor affinity, various glycoforms were analyzed using surface plasmon resonance. The system used has been well characterized and is based on previous reports employing an EPOR-Fc chimera captured on a Protein A surface. Using three variants of EPO containing different levels of sialylation, we determined that sialic acid decreased the association rate constant (k(on)) about 3-fold. Furthermore, glycosylated EPO had a 20-fold slower k(on) than nonglycosylated EPO, indicating that the core carbohydrate also negatively impacted k(on). The effect of electrostatic forces on EPO binding was studied by measuring binding kinetics in varying NaCl concentrations. Increasing NaCl concentration resulted in a slower k(on) while having little impact on k(off), suggesting that long-range electrostatic interactions are primarily important in determining the rate of association between EPO and EPOR. Furthermore, the glycosylation content (i.e., nonglycosylated vs glycosylated, sialylated vs desialylated) affected the overall sensitivities of k(on) to [NaCl], indicating that sialic acid and the glycan itself each impact the overall effect of these electrostatic forces.

Development of reference ranges in elite athletes for markers of altered erythropoiesis

BACKGROUND AND OBJECTIVES

Our previous research developed two statistical models that are useful indicators of current (ON-model) or recently discontinued (OFF-model) recombinant human erythropoietin (rHuEPO) use by athletes. The component variables of the ON-model are hematocrit (Hct), reticulocyte hematocrit (RetHct), serum erythropoietin (EPO), percent macrocytes (%Macro), and soluble transferrin receptor (sTfr), whilst the OFF-model uses only the first three variables. Genetics and training modalities of elite athletes may conceivably produce unusual values for blood parameters related to erythropoiesis. The aims of this study were to develop reference ranges in elite athletes for key hematologic parameters as well as ON- and OFF-models scores, and to evaluate the effect of ethnicity, gender, residence at moderate altitude (approximately 2000 m) and within-individual variation on the variables and model scores.

DESIGN AND METHODS

Over a period of three weeks, 413 female and 739 male elite athletes from 12 countries visited laboratories to provide three blood samples for analysis of blood parameters sensitive to erythropoiesis. For each parameter and for the ON- and OFF-model scores, we used mixed modeling to establish the range within which we could be 95% certain that the value for a randomly chosen athlete would fall, taking into account various random effects (variation within and between subjects and laboratories) and fixed effects (means for different levels of ethnicity, age, sport, altitude of residency). We performed similar analyses for changes in the ON- and OFF-model scores between the three visits.

RESULTS

Most fixed effects were accompanied by clear-cut, small to moderate differences in several parameters. However, residency at moderate altitude was accompanied by a much higher hematocrit than residency nearer sea level, with the mean (and 95% confidence limits) for the difference being 2.3 (0.9 to 3.7) and 1.8 (0.1 to 3.5) units for males and females, respectively. Males at altitude also demonstrated a moderately higher ON-model score. Otherwise the influence of these effects was small for ON-, OFF- and changes in model scores.

INTERPRETATION AND CONCLUSIONS

Assessment of an athlete's blood parameters and ON- and OFF-model scores may need adjustment for training modalities and other characteristics of the subject. Changes in model scores (together with monitoring of urine samples for the presence of rHuEPO) provide a promising approach to detection of rHuEPO abuse, because they are less sensitive to subject characteristics and less variable than raw model scores.

Epoetin alfa in cancer patients: evidence-based guidelines

Anemia is a common cause of cancer-related fatigue. A systematic review of the literature was performed to establish guidelines on the use of epoetin alfa for the treatment of anemia. The evidence in support of these guidelines was selected, reviewed, and summarized by the members of the Canadian Cancer and Anemia Guidelines Development Group. The effects of epoetin alfa on quality of life (QOL) in patients with cancer were examined in 5 randomized, placebo-controlled trials and 2 large, open-label, nonrandomized, community-based studies. The effects of epoetin alfa on red blood cell transfusion requirements were examined in 19 randomized controlled trials (RCTs) with 21 comparisons. All trials compared epoetin alfa to a suitable control group, examined specified outcome measures that could be analyzed, and studied patients with cancer who were receiving chemotherapy. Trials involving patients with hematologic malignancies originating in the bone marrow were excluded. Outcome measures included 1) quality of life (QOL) (as measured by scales including the Linear Analogue Self-Assessment [LASA] and the Functional Assessment of Cancer Therapy [FACT] subscales), and 2) transfusion requirements (as measured by the proportion of patients requiring transfusion and amount of transfusion). The analysis confirmed that epoetin alfa produced statistically significant and clinically relevant improvements in QOL in patients with cancer. The overall relative risk ratio for transfusion among patients receiving epoetin alfa was calculated to be 0.60 (95% Cl, 0.53-0.69; P < 0.00001), representing a 40% reduction in the proportion of patients requiring transfusion. These results support recommendations for the use of epoetin alfa in patients with cancer-related anemia.

Recombinant human erythropoietin in the treatment of anemic patients with hematological malignancies

Patients with malignant diseases frequently develop anemia. An alternative to blood transfusions is the application of recombinant human erythropoietin. Several nonrandomized and prospective, placebo-controlled studies have demonstrated the effect and safety of erythropoietin in patients with hematological malignancies, particularly in patients with multiple myeloma and low- to intermediate-grade non-Hodgkin's lymphoma. However, in patients with myelodysplastic syndromes, the rather low response rate of erythropoietin is overcome by the combination of erythropoietin with granulocyte colony-stimulating factor. A significant acceleration of the reconstitution of erythropoiesis has been reported in allogeneic, but not in autologous bone marrow transplantation. Especially in large open-label, multicenter studies, a statistically and clinically significant improvement in quality of life independent from chemotherapeutic response or tumor type has been demonstrated. A number of simple algorithms have been proposed using the pretreatment serum erythropoietin level, transfusion requirements, and early changes in hematological parameters.

Recombinant glycoprotein product quality in proliferation-controlled BHK-21 cells

We analyzed product quality to determine the applicability of proliferation-controlled mammalian cells for recombinant pharmaceutical protein production. Baby hamster kidney (BHK)-21 cells were engineered to express a dicistronic, stabilized, self-selecting growth control system consisting of a beta-estradiol-activatable transcription factor IRF-1 fusion protein. IRF-1 activity led to a reduced growth rate, whereas productivity, protein integrity, and glycosylation pattern of the industrially relevant secreted pharmaceutical glycoprotein erythropoietin remained consistent, showing that this technique has the potential for improving the consistency of high-quality pharmaceutical products and thus warrants further development.

[Recombinant human erythropoietin: method of in vivo evaluation using normocythemic mice]

PURPOSE

The implementation of an in vivo assay to determine the biological activity of human recombinant erythropoietin (Hu-r EPO) is essential. The purpose of this study was to perform and optimize the conditions of an easy in vivo bioassay suitable for routine testing of quality control of Hu-r EPO preparations.

MATERIAL AND METHODS

Normocythemic 8 weeks female mice treated with different Hu-r EPO doses were employed. The reticulocyte response was measured by flow cytometry and by visual count in a Neubauer cell count chamber, after selective red blood cell haemolysis. A unique subcutaneous injection with blood extraction 96 hours later was the schedule employed. The reticulocyte count measured by both methods was plotted against the log dose of Hu-r EPO.

RESULTS

The dose-response curve obtained was linear between 5 and 160 UI/mouse and the doses chosen for future assays were 10, 30 and 90 UI/mouse. The use of at least 6 animals per dose and not less than 3 assays to obtain reliable limits according to international regulations is convenient. Thirty assays were performed in four different samples and were analyzed by parallel lines (3 + 3) relating the response with the log dose. The coefficient of correlation between both methods was 0.989, so they are equivalent.

CONCLUSIONS

This method is suitable because fewer animals and bioassays are necessary to obtain fiducial limits according to international requirements. It is in agreement with the tendency to reduce the number of animals used for bioassay because ethical and economic reasons.

[Study on evaluating methods for the quality control of glycoprotein products. (II)--Erythropoietin products. Part 2]

Using recombinant human erythropoietin (rh-EPO) from three different sources, the usefulness of HPAEC-PAD (high-pH anion exchange chromatography with pulsed amperometric detection) for evaluation of carbohydrate moieties of rh-EPO products was evaluated. It is well known that in vivo bioactivity and metabolic fate of EPO are dependent on the number of sialic acids and the degree of branching in the carbohydrate moieties. Here we show that HPAEC analysis reveals differences in the number of sialic acids as well as in the structure of desialylated N-glycans among the rh-EPO products. Therefore, HPAEC is useful for evaluation of the quality of rh-EPO products.

Erythropoietin: physiologic and pharmacologic aspects

The purpose of this review is to give an update of the recent progress in research on erythropoietin (Epo), the hormone that regulates red blood cell production. Epo is a glycoprotein with a molecular mass of approx 30 kDa, which circulates in plasma of the human with 165 amino acids with three N-linked and one O-linked acidic oligosaccharide side chains in the molecule. Both the alpha (39% CHO) and beta (24% CHO) forms are available for clinical use, and there does not appear to be any difference in the pharmacokinetics of these two forms of Epo. Radioimmunoassays and enzyme-linked immunoabsorbant (ELISA) assays are available in a kit form. Serum levels of Epo in normal human subjects range between 1 and 27 mmu/ml or approx 5 pmol/l. It seems clear that the cells in the adult mammalian kidney which produce Epo are the interstitial cells in the peritubular capillary bed and the perivenous hepatocytes in the liver. Expression of the human Epo gene sequences that direct expression in the kidney are located 6-14 kilobases 5' to the gene; whereas the sequences that control hepatocyte-specific expression are located within 0.7 KS to the 3'-flanking region and 0.5 KS to the 5'-flanking region. The signal transduction pathways postulated to be involved in the expression of Epo are: kinases A, G and C; both a constitutive factor and a second hypoxia-inducible factor-1 (HIF-1) located in the 5' end of an hypoxia inducible enhancer region of the Epo gene; and reactive oxygen species. The primary target cell in the bone marrow acted on by Epo is the colony-forming unit erythroid (CFU-E) which has the highest number of Epo receptors. It has been postulated that Epo decreases the rate which Epo-dependent progenitor cells undergo programed cell death (apoptosis). There are two major signal transduction pathways activated by the Epo receptor: the JAK2-STAT5 pathway and the ras pathway. Both pathways involve tyrosine phosphorylation. The approved clinical uses of Epo are the anemias associated with end-stage renal disease, cancer chemotherapeutic agents, and patients with HIV infection receiving AZT. Other anemias reported to respond to Epo therapy are anemia of prematurity, rheumatoid arthritis, and myelodysplasia. Other uses of Epo under investigation are in perioperative surgery and preoperative autologous blood donation.

[Blood erythropoietin levels in healthy subjects studied in the valley of Mexico]

Erythropoietin (EPO) is the hematopoietic growth factor that regulates red cell production. There is a direct relationship between its secretion and tissue hypoxia. Above sea level, oxygen concentration diminishes. This causes an increase of hemoglobin and hematocrit; this effect could be the consequence of higher EPO levels. Currently, evaluation of baseline serum EPO levels is very important in the differential diagnosis of anemia and erythrocytosis. The purpose of the present work was to report the EPO levels on a group of healthy blood donors living in Mexico City, 2,240 m above sea level. Two-hundred twenty blood donors were selected to measure serum EPO; there were 168 males and 52 females. Median EPO levels of the entire population were 7.5 mU/mL (percentile interval, PI, 1-18). Median EPO levels were 7.6 (PI 1-18) and 7.5 (PI 1-16.9) for men and women, respectively. We did not find differences in serum EPO levels among previous reports in other populations and the values determined in this study.

Treatment of pure red cell aplasia after major ABO-incompatible bone marrow transplantation resistant to erythropoietin. Bone Marrow Transplantation Team

A case of pure red cell aplasia after major ABO-incompatible bone marrow transplantation with long duration of up to 482 days is presented. The patient exhibited resistance to treatment using intravenous gamma globulin, prednisolone and 8 week administration of erythropoietin. The patient finally responded to treatment using erythropoietin and methylprednisolone simultaneously. Because of its safety and efficacy, it might be worthwhile to try erythropoietin with methylprednisolone, if necessary, for pure red cell aplasia complicating major ABO-incompatible bone marrow transplantation.

The International Standard for Recombinant DNA-derived Erythropoietin: collaborative study of four recombinant DNA-derived erythropoietins and two highly purified human urinary erythropoietins

The International Standard (IS) for Recombinant DNA-Derived (rDNA) Erythropoietin (EPO) (in ampoules coded 87/684) and three other rDNA EPO preparations in ampoules coded 87/690, 87/696 and 88/574 respectively, were compared with two preparations of highly purified human urinary (HU) EPO and the 2nd International Reference Preparation of Human Urinary Erythropoietin for Bioassay (2nd IRP) by 26 laboratories in 11 countries using a wide range of in-vivo and in-vitro bioassays and immunoassays. These EPO preparations were also compared by electrophoresis and isoelectric focusing. Estimates of EPO content in terms of the 2nd IRP by all in-vivo bioassay methods gave combined unweighted geometric means (with 95% fiducial limits) of: 86 (75-99) IU/ampoule for the IS, 81 (70-94) IU/ampoule for 87/690, 58 (48-71) IU/ampoule for 87/696 and 120 (100-143) IU/ampoule for 88/574. Mean estimates of EPO content in terms of the 2nd IRP by in-vitro bioassays (except receptor assays) were larger than, and those by immunoassays were similar to, the mean estimates by in-vivo bioassays. The use of purified rDNA or HU EPO as standards in place of the 2nd IRP reduced the inter-laboratory variability of estimates of purified EPO preparations by in-vivo and in-vitro bioassays and by immunoassays, and reduced the variability of overall mean estimates for each of these preparations between the three types of method. The inter-laboratory variability of immunoassay estimates of human serum EPO was similar whether the 2nd IRP or one of the purified EPOs was used as standard. Significant differences in in-vivo and in-vitro biological, immunological and physicochemical properties were found between these four rDNA EPO preparations and between them and the HU EPO in the two purified preparations and in the 2nd IRP. There were also differences between the immunoreactivities of the two serum EPO samples included in the study, and between them and the immunoreactivities of the purified EPOs. The differences between rDNA EPOs appeared to be related to differences between the cells used for their biosynthesis, but may also be the result of differences in purification methods and of inter-batch variations. Significant differences in assay specificity were observed within each of the three general types of method. The specificity of the in-vivo bioassays was influenced by the route of hormone administration. The specificities of the mouse spleen cell in-vitro bioassays differed from that of the mouse spleen receptor-binding assay.(ABSTRACT TRUNCATED AT 400 WORDS)

An enzyme-linked immunosorbent assay for erythropoietin using monoclonal antibodies, tetrameric immune complexes, and substrate amplification

We recently reported the development of several monoclonal antibodies (MoAbs) to native human erythropoietin (Ep). In the present study we have used the two antibodies with highest affinity to develop a two-sided or sandwich enzyme-linked immunosorbent assay (ELISA) to measure Ep in human serum. In this assay Ep is incubated in microtiter wells precoated with the first (IgE) anti-Ep antibody. Assay wells are then incubated with the second (IgG1) anti-Ep antibody, which is labeled noncovalently with the enzyme alkaline phosphatase (AP) by means of bispecific tetrameric antibody complexes consisting of IgG1 anti-Ep cross-linked to IgG1 anti-AP using rat MoAbs specific for mouse IgG1. Application of this noncovalent labeling procedure, in combination with substrate amplification, results in a detection sensitivity of 0.5 to 1.0 mU/sample (5 to 10 mU/mL), which makes this assay suitable for measuring normal serum Ep levels. The validity of this ELISA for quantitating Ep in biological fluids was demonstrated by the parallelism obtained between pure recombinant Ep dose-response curves and those obtained with plasma and serum from healthy donors and patients with various hematologic disorders. Normal plasma Ep levels detected with this ELISA ranged from 9 to 101 mU/mL with a mean of 32 +/- 23 (SD) mU/mL. Ep levels in sera from patients with polycythemia vera were in the low to normal range, whereas Ep levels in sera from patients with secondary polycythemia and patients with aplastic anemia were moderately to strongly elevated. These results demonstrate that the Ep-ELISA is a sensitive, reliable, and nonradioactive immunologic method for quantitating Ep levels and should prove useful in a variety of clinical and laboratory settings.

The second international reference preparation of erythropoietin, human, urinary, for bioassay

A collaborative study of the second international Reference Preparation of Erythropoietin, Human, Urinary, for Bioassay was carried out in 10 laboratories. Combined potency estimates obtained by comparison with the International Reference Preparation, indicate that ampoules of the second Preparation contain 10.0 IU (weighted mean potency) or, taking the unweighted mean potency, 9.8 IU, with fiducial limits (P=0.95) of 8.4-11.5 IU. The second Preparation could be used as a standard in estimating the potency of a preparation of sheep plasma erythropoietin (68/307) although, as with the International Reference Preparation, there was a tendency for the sheep plasma preparation to produce log-dose-log-response regression lines that were steeper than those produced by the second Preparation.In accelerated degradation studies of the second Preparation stored as the dry product in ampoules for up to 1 year, there was no consistent trend to indicate instability of the preparation.Following its establishment in 1971, the Second International Reference Preparation was allocated a potency of 10 IU/ampoule.