Clinical and economic impact of epoetins in cancer care

Impact of Granulocyte Colony-Stimulating Factor (G-CSF) and Epoetin (EPO) on Hematologic Toxicities and Quality of Life in Patients During Adjuvant Chemotherapy in Early Breast Cancer: Results From the Multi-Center Randomized ADEBAR Trial

BACKGROUND

Hematologic toxicities are one of the greatest challenges in adjuvant chemotherapy for breast cancer. This analysis of the ADEBAR trial aims to evaluate application and effect of granulocyte colony-stimulating factor (G-CSF) and epoetin alfa (EPO) on hematologic parameters and fatigue in patients with breast cancer during chemotherapy.

PATIENTS AND METHODS

In the ADEBAR trial, 1493 patients with node-positive primary breast cancer were randomized to either 6 × 5-fluorouracil, epirubicin, and cyclophosphamide (FEC120) or 4 × epirubicin and cyclophosphamide followed by 4 × docetaxel (EC-DOC). Co-medication with G-CSF or EPO was applied to treat chemotherapy-induced leukopenia or anemia. Fatigue was assessed at baseline and after one-half of the chemotherapy.

RESULTS

In total, 899 patients could be included in the analysis. There was no evidence for an association between leucocyte or hemoglobin levels and application of G-CSF and EPO in the preceding cycle, respectively. Hemoglobin levels (B = -0.41; P < .001) were affected by treatment regimen. Fatigue during chemotherapy was mostly affected by the level of fatigue before the start of chemotherapy (B = 0.41; P < .001). Patients with G-CSF application in the preceding cycle showed an increased fatigue score (B = 5.43; P = .02).

CONCLUSION

We showed that fatigue during adjuvant chemotherapy was mostly affected by the level of fatigue present before the start of chemotherapy. This result suggests that the level of fatigue before the start of treatment should be included as an important factor when deciding on type and toxicity of chemotherapy in early breast cancer.

The economic burden of common adverse events associated with metastatic colorectal cancer treatment in the United States

AIMS

Adverse events (AEs) associated with treatments for metastatic colorectal cancer (mCRC) may compromise the course of treatment, impact quality-of-life, and increase healthcare resource utilization. This study assessed the direct healthcare costs of common AEs among mCRC patients in the US.

METHODS

Adult mCRC patients treated with chemotherapy or targeted therapies were identified from administrative claims databases (2009-2014). Up to the first three mCRC treatment episodes per patient were considered and categorized as with or without the AE system/organ category during the episode. Total healthcare costs (2014 USD) were measured by treatment episode and reported on a monthly basis. Treatment episodes with the AE category were matched by treatment type and line of treatment to those without the AE category. Adjusted total cost differences were estimated by comparing costs during treatment episodes with vs without the AE category using multivariate regression models; p-values were estimated with bootstrap.

RESULTS

A total of 4158 patients with ≥1 mCRC treatment episode were included (mean age = 59 years; 58% male; 60% with liver and 14% with lung metastases; 2,261 [54%] with a second and 1,115 [27%] with a third episode). On average, two treatment episodes were observed per patient with an average length of 166 days per episode. Adjusted monthly total cost difference by AE category included hematologic ($1,480), respiratory ($1,253), endocrine/metabolic ($1,213), central nervous system (CNS; $1,136), and cardiovascular ($1,036; all p < .05).

LIMITATIONS

Claims do not include information on the cause of AEs, and potentially less severe AEs may not have been reported by the physician when billing the medical service. This study aimed to assess the association between costs and AEs and not the causation of AEs by treatment.

CONCLUSIONS

The most costly AEs among mCRC patients were hematologic, followed by respiratory, endocrine/metabolic, CNS, and cardiovascular.

Cost Analysis of Erythropoietic-Stimulating Therapy Dosing in Oncology Inpatients

Background:

Inpatient costs associated with different erythropoietic-stimulating therapy regimens have not been compared in an oncology setting.

Objective:

To conduct a cost analysis of different regimens of epoetin alfa (EPO) and darbepoetin alfa (DARB) in an inpatient oncology setting.

Methods:

A retrospective evaluation of oncology diagnosis-related group discharges during 2003, in 30 community hospitals, identified EPO treatment patterns. Wholesale acquisition costs were determined for patients who received EPO 40 000 units or more once weekly. Potential differences in costs were calculated using conversion ratios for an equivalent EPO dose 3 times weekly or DARB dose once weekly (EPO:DARB ratio 260:1, approximating DARB 150 μg once weekly). A sensitivity analysis was performed using an EPO:DARB ratio of 400:1, approximating DARB 100 μg once weekly (1.5 μg/kg).

Results:

Among the 1410 EPO doses administered (n = 677 pts.), a dose of 40000 units or more was used 44% of the time (n = 311 pts.), with dosing initiated on average 5.6 days after admission. For these 311 evaluable patients, switching from EPO 40 000 units once weekly to EPO 10 000 units 3 times weekly reduced per-patient and total drug acquisition costs by approximately 50% ($704 vs $359 and $218 938 vs $111 615, respectively). Relative to EPO once weekly, switching patients to DARB resulted in increased drug acquisition costs at the 260:1 conversion and lower costs at the 400:1 conversion. However, EPO 3 times weekly remained the least costly option by 44–63%. The cost-savings realized with EPO 10000 units 3 times weekly increased with longer duration of hospitalization.

Conclusions:

In an inpatient setting, use of EPO 10000 units 3 times weekly may minimize expenditures associated with treatment of cancer-related anemia using erythropoietic-stimulating therapies.

The effectiveness and cost-effectiveness of erythropoiesis-stimulating agents (epoetin and darbepoetin) for treating cancer treatment-induced anaemia (including review of technology appraisal no. 142): a systematic review and economic model

BACKGROUND

Anaemia is a common side effect of cancer treatments and can lead to a reduction in quality of life. Erythropoiesis-stimulating agents (ESAs) are licensed for use in conjunction with red blood cell transfusions to improve cancer treatment-induced anaemia (CIA).

OBJECTIVE

To investigate the effectiveness and cost-effectiveness of ESAs in anaemia associated with cancer treatment (specifically chemotherapy).

DATA SOURCES

The following databases were searched from 2004 to 2013: The Cochrane Library, MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health Literature, British Nursing Index, Health Management Information Consortium, Current Controlled Trials and ClinicalTrials.gov. The US Food and Drug Administration and European Medicines Agency websites were also searched. Bibliographies of included papers were scrutinised for further potentially includable studies.

REVIEW METHODS

The clinical effectiveness review followed principles published by the NHS Centre for Reviews and Dissemination. Randomised controlled trials (RCTs), or systematic reviews of RCTs, of ESAs (epoetin or darbepoetin) for treating people with CIA were eligible for inclusion in the review. Comparators were best supportive care, placebo or other ESAs. Anaemia- and malignancy-related outcomes, health-related quality of life (HRQoL) and adverse events (AEs) were evaluated. When appropriate, data were pooled using meta-analysis. An empirical health economic model was developed comparing ESA treatment with no ESA treatment. The model comprised two components: one evaluating short-term costs and quality-adjusted life-years (QALYs) (while patients are anaemic) and one evaluating long-term QALYs. Costs and benefits were discounted at 3.5% per annum. Probabilistic and univariate deterministic sensitivity analyses were performed.

RESULTS

Of 1457 titles and abstracts screened, 23 studies assessing ESAs within their licensed indication (based on start dose administered) were included in the review. None of the RCTs were completely aligned with current European Union licenses. The results suggest a clinical benefit from ESAs for anaemia-related outcomes and an improvement in HRQoL scores. The impact of ESAs on AEs and survival remains highly uncertain, although point estimates are lower, confidence intervals are wide and not statistically significant. Base-case incremental cost-effectiveness ratios (ICERs) for ESA treatment compared with no ESA treatment ranged from £ 19,429 to £ 35,018 per QALY gained, but sensitivity and scenario analyses demonstrate considerable uncertainty in these ICERs, including the possibility of overall health disbenefit. All ICERs were sensitive to survival and cost.

LIMITATIONS

The relative effectiveness of ESAs was not addressed; all ESAs were assumed to have equivalent efficacy. No studies were completely aligned with their European labelling beyond the starting dose evaluated. There is questionable generalisability given that the included trials were published >20 years ago and there have been many changes to chemotherapy as well as to the quality of supportive treatment. Trial quality was moderate or poor and there was considerable unexplained heterogeneity for a number of outcomes, particularly survival, and evidence of publication bias. Adjustments were not made to account for multiple testing.

CONCLUSIONS

ESAs could be cost-effective when used closer to licence, but there is considerable uncertainty, mainly because of unknown impacts on overall survival.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005812.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Costs of care for lung and colon cancer patients receiving chemotherapy following FDA policy changes

PURPOSE

Use of erythropoiesis-stimulating agents (ESAs) in US cancer care declined amidst post-marketing evidence of adverse effects and the Food and Drug Administration's (FDA) addition of a "black-box" warning to product labeling in March 2007. Because reduced ESA use may have led to more transfusions or increased anemia-related health care needs, we measured the policy's impact on health care costs of lung and colon cancer patients receiving chemotherapy.

METHODS

In a retrospective cohort study of 13,630 lung and 3,198 colon cancer patients in the Department of Veterans Affairs (VA) between 2002 and 2008, we calculated anemia treatment (ESA and transfusion), cancer- and non-cancer-related, and total health care costs for the chemotherapy episode of care. We used multivariable regression to examine health care costs and utilization between patients whose chemotherapy was administered before (PRE) or after (POST) March 1, 2007.

RESULTS

ESA costs declined and transfusion costs were similar, resulting in lower overall POST-period anemia treatment costs (lung, $526 lower, P < 0.01; colon, $504 lower, P < 0.01). Other cancer-related health care costs increased, resulting in markedly higher POST-period total health care costs (lung, $4,706 higher, P < 0.01; colon, $11,414 higher, P < 0.01).

CONCLUSIONS

Although chemotherapy episode anemia treatment costs declined after the black-box warning, the savings were offset by increases in other cancer-related costs. Those increases were mainly in outpatient services and pharmacy, suggesting that likely drivers include adoption of new high-cost diagnostic approaches and therapeutic modalities. Additional research is needed to determine the effects of anemia management changes on patient outcomes and to more fully understand cost-benefit relationships in cancer treatment.

Dose reduction of epoetin-alpha in the prevention of chemotherapy-induced anaemia

INTRODUCTION

Anaemia during chemotherapy is often left untreated. Erythropoiesis-stimulating agents are frequently used to treat overt anaemia. Their prophylactic use, however, remains controversial and raises concerns about cost-effectiveness. Therefore, we assessed the efficacy of a dose-reduction schedule in anaemia prophylaxis.

MATERIALS AND METHODS

The study included patients with untreated solid tumours about to receive platinum-based chemotherapy and had haemoglobin (Hb) levels ≥11 g/dL. Epoetin-α was administered at a dose level of 3 × 10,000 U weekly as soon as Hb descended to < 13 g/dL. Dose reductions to 3 × 4,000 U and 3 × 2,000 U weekly were planned in 4-week intervals if Hb stabilised in the range of 11-13 g/dL. Upon ascending to ≥13 g/dL, epoetin was discontinued. Iron supplements of 100 mg intravenous doses were given weekly. Of 37 patients who enrolled, 33 could be evaluated.

RESULTS AND DISCUSSION

Their median Hb level was 13.7 (10.9-16.2) g/dL at baseline and descended to 11.0 (7.4-13.8) g/dL by the end of chemotherapy. Anaemia (Hb < 10 g/dL) was prevented in 24 patients (73%). The mean dose requirement for epoetin-α was 3 × 5,866 U per week per patient, representing a dose reduction of 41%. Treatment failed in nine patients (27%), in part due to epoetin-α resistance in four (12%) and blood transfusion in three (9%) patients.

CONCLUSION

Dose reduction was as effective as fixed doses in anaemia prophylaxis but reduced the amount of prescribed epoetin substantially.

Management of anaemia: a critical and systematic review of the cost effectiveness of erythropoiesis-stimulating agents

Erythropoiesis-stimulating agents (ESAs) are genetically engineered forms of erythropoietin that are used in the treatment of anaemia. Their successful use in the treatment of anaemia associated with renal disease, cancer and other diseases, as well as the development of multiple agents, has increased the visibility of these agents in the clinical and health economics literature. The circumstances under which the use of ESAs is cost effective, or indeed, whether it is cost effective, is of central concern for clinicians and payers who must make informed decisions regarding the management of these costly resources. Much of the recent literature on ESAs in the treatment of anaemia associated with chronic kidney disease and cancer, the two major therapeutic areas for ESA treatment, has focused on comparisons between individual ESAs, particularly epoetin alfa and darbepoetin alfa. While there have been some studies of cost effectiveness, many studies in these treatment areas have employed a cost-minimization approach and have relied on published prices rather than actual market prices. In general, this review of the literature suggests a cost advantage for epoetin alfa relative to darbepoetin alfa in the treatment of anaemia in renal and oncology indications. For other indications in which the literature is less developed, such as anaemia induced by antiviral therapy and blood management in surgery, small prospective studies or decision-analytic models comparing ESA therapy and standard care have been most common. Few conclusions can be drawn about the overall and relative costs or cost effectiveness of ESAs in these treatment areas. With the recent concerns about the safety of ESAs, especially when used outside the approved product labelling, future evaluations of epoetin alfa and darbepoetin alfa should factor their safety profiles into estimates of cost effectiveness. Moreover, additional studies are needed to evaluate whether the treatment of anaemia with ESAs is cost effective compared with no treatment or minimal blood transfusions, and whether the cost effectiveness of ESAs would be improved if ESA doses and durations were reduced. With the introduction of new longer-acting ESAs, such as the continuous erythropoietin receptor activator, the relative cost effectiveness among the different ESAs will continue to be an important question for public and private payers, policy makers and clinicians who must consider the emergence of new data and changing dosing patterns when making decisions about the use of these important but costly agents.

Critical appraisal of scientific posters comparing anemia treatments for cancer patients: Applying ispor task force guidelines on methodological quality of retrospective studies

Two independent reviewers used the methodological criteria published by the ISPOR Task Force on Retrospective Data to assess the quality of four posters presenting the results of retrospective database studies on the use of erythropoiesis-stimulating agents (epoetin alfa, epoetin beta, or darbepoetin alfa) for treating patients with cancer. A third reviewer consolidated the results. Overall, from the information reported in the four posters, their methodological quality ranged from poor to very poor; only a few of the criteria were satisfactorily addressed. The quality of the data sources and the research design received very poor scores. Key elements such as selection bias were not considered. These findings caution against the use of posters without appropriate assessment of their methodological quality. The ISPOR guidelines for the evaluation of retrospective analyses are a useful tool for assessing the quality of scientific posters.

Economic burden of haematological adverse effects in cancer patients: a systematic review

OBJECTIVE

Patients receiving cancer treatments commonly experience haematological adverse effects (AEs) related to chemotherapy or molecularly targeted therapies, which may be associated with high healthcare costs. The objective of this review was to summarise the published literature on the economic burden of neutropenia, thrombocytopenia and anaemia as AEs of cancer treatment.

METHODS

A systematic search of the medical literature published between 1990 and 2006 was conducted using PubMed/MEDLINE, EMBASE, BIOSIS, related article links and supplemental searches. References selected for inclusion were prospective or retrospective studies specifically designed to examine the burden of illness, direct medical costs, indirect costs and/or cost drivers associated with neutropenia, thrombocytopenia and anaemia in adult cancer patients. All costs are reported as originally published and adjusted to 2006 US dollars.

RESULTS

In the US, the cost of neutropenia ranged from $US 1893 (2006 value $US 2632) per outpatient episode to $US 38,583 ($US 49,917) per febrile neutropenia hospitalisation. For countries outside the US, the cost of neutropenia appeared to be lower. The cost of thrombocytopenia ranged from $US 1035 ($US 1395) to $US 5328 ($US 7635) per cycle or episode in the US. Costs attributable to anaemia ranged from $US 18,418 ($US 22,775) to $US 69,478 ($US 93,454) per year in the US. The costs of AEs for patients with haematological malignancies appeared to be up to 2-3 times higher than those for patients with solid tumours. Economic studies of the cost of haematological AEs specific to new molecularly targeted treatments for haematological malignancy have not been published.

CONCLUSIONS

Chemotherapy-related haematological AEs result in a substantial economic burden on patients, payers, caregivers and society in general. Because of their burden, the frequency and severity of these toxicities should be one of the key factors in the selection of optimal treatments for patients with cancer, especially those with haematological malignancies. Future research is needed to assess the economic burden of AEs associated with new molecularly targeted treatments for haematological malignancies.

Injectable hyaluronic acid microhydrogels for controlled release formulation of erythropoietin

An injectable hyaluronic acid (HA) microhydrogel was successfully developed as a novel drug carrier for controlled release formulation of protein drugs. HA hydrogels were prepared by the disulfide bond formation of thiolated HA (HA-SH). EPO was loaded in situ during HA-SH hydrogel preparation using an accelerating agent of sodium tetrathionate. The gelation time was drastically reduced from a day to 30 min when sodium tetrathionate was added for HA-SH hydrogel preparation. In vitro release of EPO in PBS at 37 degrees C showed that EPO was rapidly released for 3 days with an initial burst and then slowly up to 9 days from HA-SH hydrogels. HA-SH microhydrogels were prepared by the reactive spray drying of diluted HA-SH precursor solution. The mean particle size was approximately 2.3 mum and the water content after spray drying was approximately 14%. Ellman's test showed that sodium tetrathionate contributed not only for rapid crosslinking reaction but also for the reduction of residual free thiol content in HA-SH microhydrogels after spray drying. EPO recovery from HA-SH microhydrogels after degradation with hyaluronidase SD was higher than 95%. The released EPO appeared to be intact from the analysis with RP-HPLC. According to in vivo release test of EPO from HA-SH microhydrogels in Sprague Dawley (SD) rats, elevated plasma concentration of EPO higher than 0.1 ng/mL, which is a critical minimal concentration for EPO efficacy, was maintained up to 7 days. There was no adverse effect during and after the in vivo tests.

Current impact of gene technology on healthcare

OBJECTIVES

It has been claimed that gene technology will induce revolutionary changes in healthcare. This paper investigates how and to what extent these changes have been economically assessed.

METHODS

A generic framework was developed to distinguish between methodologically similar evaluations of healthcare technology. Methodological issues and the current state of economic evidence concerning human DNA technology were extracted from publications within these groups of evaluations.

RESULTS

Economic evaluations of "healthcare consisting of gene technology" were identified primarily for in vitro diagnostics for hereditary disease and others for pharmacogenetics and molecular pathology. "Healthcare enabled by gene technology" is far more encompassing and includes, e.g., biotechnology drugs for which various health economic evaluations can be found. Yet here, the impact of gene technology intertwines with the impact of other technologies and is therefore hardly susceptible to evaluation. The fields of evaluation may be classified best according to the two dimensions "purpose" and "stage of development". Current evaluations cover screening, diagnostic and treatment technologies in investigational, new and established stages. Apart from prenatal screening, healthcare consisting of gene technology was cost saving only for genotype tests replacing continuous phenotype tests and for one pharmacogenetic test. Conclusive evidence of favourable cost-effectiveness ratios is available only for few conditions.

CONCLUSION

Hypotheses about the impact of gene technology on healthcare must be explicit about the definition of "genetic" medicine. A general statement regarding healthcare enabled by gene technology is not possible. Based on current evidence, an era of healthcare consisting of gene technology built on widespread predictive testing is not desirable from a health economic viewpoint.

Recombinant erythropoietin for chemotherapy-related anaemia: economic value and health-related quality-of-life assessment using direct utility elicitation and discrete choice experiment methods

OBJECTIVE

To assess both the health-related quality of life (HR-QOL) and the economic value of erythropoietin treatment in chemotherapy-related anaemia using direct utility elicitation and discrete choice experiment (DCE) methods from a societal perspective in the UK.

METHODS

The time trade-off (TTO) method was employed to obtain utility values suitable for the calculation of QALYs for no, mild, moderate and severe anaemia. Health-state descriptions were developed using the Functional Assessment of Cancer Therapy - Anaemia (FACT-AN) subscale and the EQ-5D questionnaires, and were validated by clinical experts and patients. In addition, a DCE was implemented to elicit preferences for various anaemia treatment scenarios. The DCE analysis comprised important aspects of treatment identified from a literature review and by consultation with expert clinicians and cancer patients. The DCE included cost as an attribute in order to elicit willingness-to-pay (WTP) values (pound, 2004 values). The two methods were applied in the same cross-sectional sample of 110 lay people. Face-to-face interviews were conducted between February and March 2004.

RESULTS

The mean utility scores were 0.86 (standard error [SE] 0.014) for the no-anaemia state, and 0.78 (SE 0.016), 0.61 (SE 0.020) and 0.48 (SE 0.020) for the mild, moderate and severe anaemia states, respectively. The DCE results revealed the following preferences as significant predictors of choice: higher level of relief from fatigue, lower duration of administration, subcutaneous/intravenous administration versus cannula injection, GP versus hospital location, lower risk of infection or allergic reactions and lower cost per month to the patient. Attribute levels were valued higher for recombinant erythropoietin than for blood transfusion; this is reflected in an incremental welfare value of 368 pounds (95% CI 318, 419).

CONCLUSIONS

The results highlight a societal view that the severity of chemotherapy-related anaemia will significantly affect cancer patients' HR-QOL. The DCE survey shows that the public value favourably the attributes of treatment with recombinant erythropoietin, and indicates a likely patient preference for treatment with recombinant erythropoietin over blood transfusion.

Sustained release formulation of erythropoietin using hyaluronic acid hydrogels crosslinked by Michael addition

A novel sustained release formulation of erythropoietin (EPO) was successfully developed using hyaluronic acid (HA) hydrogels crosslinked by Michael addition. Adipic acid dihydrazide grafted HA (HA-ADH) was prepared and then modified into methacrylated HA (HA-MA). (1)H NMR analysis showed that the degrees of HA-ADH and HA-MA modification were 69 and 29 mol%, respectively. Using the specific crosslinkers of dithiothreitol (DTT) and peptide linker, EPO was loaded during HA-MA hydrogel preparation by Michael addition chemistry between thiol and methacrylate groups. The amount of EPO recovered from both hydrogels after degradation with hyaluronidase SD (HAse SD) was about 90%. The crosslinking reaction with peptide linker (GCYKNRDCG) was faster than that with DTT. The gelation time was about 30 min for peptide linker and 180 min for DTT. In vitro release test of EPO from HA-MA hydrogel at 37 degrees C showed that EPO was released rapidly for 2 days and then slowly up to 7 days from HA-MA hydrogels. The released EPO appeared to be intact from the analysis with RP-HPLC. According to in vivo release test of EPO from HA-MA hydrogels crosslinked with the peptide linker in Sprague-Dawley (SD) rats, elevated plasma concentration of EPO was maintained up to 7 days. There was no adverse effect during and after the in vivo tests.

Clinical and economic impact of epoetin in adjuvant-chemotherapy for breast cancer

INTRODUCTION

Anaemia is a common toxicity in cancer patients and epoetins (EPOs) are now an established treatment. The economic profile of EPO treatment was assessed in patients with breast cancer treated by adjuvant-chemotherapy.

MATERIALS AND METHODS

Two strategies were compared: without treatment by EPO and with the possible use of treatment by EPO (epoetin alfa) when required. The clinical effectiveness criterion was time adjusted to quality of life and economic data included only direct medical costs.

MAIN RESULTS

One hundred ninety-two patients were included. In the group with the strategy containing the possible use of EPO, 45.5% of patients effectively received EPO. A significant difference in the haemoglobin level profile over time was observed which provided a significant overall benefit of 0.0052 (p<10(-4)) quality-adjusted life year (QALY) associated with an extra cost of <euro>1,615 (p<10(-4)). In the base case analysis, the cost per added QALY was estimated as <euro>310,577 with the strategy containing the possible use of EPO.

CONCLUSION

This robust result seems to be unacceptable, but the only relevant point of discussion might be the level of acceptable incremental cost-effectiveness ratio (ICER) for a patient.

Routine once-weekly darbepoetin alfa administration is cost-effective in lung cancer patients with chemotherapy-induced anemia: A Markov analysis

BACKGROUND

Despite the clinical efficacy of recombinant human erythropoietin (RHE) on chemotherapy-induced anemia, most cost-effectiveness studies have given unfavorable results.

OBJECTIVE

To determine the cost of managing anemia in unselected patients receiving chemotherapy for lung cancer, and the efficacy and cost-effectiveness of RHE.

METHOD

We constructed Markov models of two cohorts of patients who received (n=94) or did not receive (n=89) darbepoetin (one weekly injection when the hemoglobin level fell below 11 g/dl), focusing on changes in hemoglobin levels, transfusion requirements, anemia management costs, and the cost-effectiveness ratios of the two management strategies.

RESULTS

The use of RHE significantly reduced the proportion of patients needing transfusions (from 33.6% to 19.1%, p<0.05) and the number of red cell units used by transfusion (from 2.97+/-1.47 to 2.11+/-0.47, p<0.01). Markov modeling showed that the RHE strategy significantly increased the mean Hb level (13+/-0.5 g/dl versus 11.9+/-1g/dl, p<0.001), at the price of an increase in the main cost (respectively, US$ 1732+/-897 and 996+/-643; p<0.01). The cost-effectiveness ratio favored the RHE strategy (7.02 versus 9.04). Sensitivity analysis showed that the RHE strategy remained dominant in most situations.

CONCLUSION

Routine use of RHE appears to be cost-effective in patients receiving chemotherapy for lung cancer.

Selectively crosslinked hyaluronic acid hydrogels for sustained release formulation of erythropoietin

A novel sustained release formulation of erythropoietin (EPO) was developed using hyaluronic acid (HA) hydrogels. For the preparation of HA hydrogels, adipic acid dihydrazide grafted HA (HA-ADH) was synthesized and analyzed with (1)H NMR. The degree of HA-ADH modification was about 69%. EPO was in situ encapsulated into HA-ADH hydrogels through a selective cross-linking reaction of bis(sulfosuccinimidyl) suberate (BS(3)) to hydrazide group (pK(a) = 3.0) of HA-ADH rather than to amine group (pK(a) > 9) of EPO. The denaturation of EPO during HA-ADH hydrogel synthesis was drastically reduced with decreasing pH from 7.4 to 4.8. The specific reactivity of BS(3) to hydrazide at pH = 4.8 might be due to its low pK(a) compared with that of amine. In vitro release of EPO in phosphate buffered saline at 37 degrees C showed that EPO was released rapidly for 2 days and then slowly up to 4 days from HA-ADH hydrogels. When the hydrogels were dried at 37 degrees C for a day, however, longer release of EPO up to 3 weeks could be demonstrated. According to in vivo release test of EPO from HA-ADH hydrogels in SD rats, elevated EPO concentration higher than 0.1 ng/mL could be maintained from 7 days up to 18 days depending on the preparation methods of HA-ADH hydrogels. There was no adverse effect during and after HA-ADH hydrogel implantation.

Efficacy and immunogenicity of novel erythropoietic agents and conventional rhEPO in rats with renal insufficiency

Recombinant human erythropoietin (rhEPO) is used to treat anemia in chronic renal insufficiency. Erythropoietin (EPO) immunogenicity can lead to EPO-resistant anemia. Conjugating proteins with polyethylene glycol (PEG) can prolong elimination half-life and diminish protein immunogenicity. We investigated the efficacy of new erythropoietic agents, synthesized by single (Ro 50-3821) and multiple (MIX) integrations of PEG and succinimidyl butanoic acid with rhEPO, in rats with chronic renal insufficiency. Sprague-Dawley rats with surgically induced renal insufficiency received Ro 50-3821 or MIX subcutaneously (s.c.) over 4-12 weeks compared to rhEPO and NaCl. Hemoglobin and antibody levels served as primary efficacy and safety variables. Dosing intervals and dose-response characteristics were investigated. Ro 50-3821 (2.5 microg/kg once weekly) increased hemoglobin levels by 7 g/dl after 4 weeks compared to 1 g/dl in NaCl controls (P<0.05). MIX (2.5 microg/kg once weekly) and rhEPO (0.25 microg/kg three times weekly) increased hemoglobin levels by 3 g/dl. Ro 50-3821 administered for 12 weeks (0.75 microg/kg once weekly) increased hemoglobin levels (from 13 to 19 g/dl) more effectively than rhEPO (0.75 microg/kg once weekly, decline from 13 to 11 g/dl, P<0.05). No antibodies against Ro 50-3821 were detected after 12 weeks of treatment. Antibodies against rhEPO were seen in 69% of animals (P<0.00001). Ro 50-3821 increased hemoglobin levels with once weekly s.c. dosing. Multiple pegylated EPO is less effective. In rats, rhEPO failed to increase hemoglobin levels with once weekly long-term dosing. Antibody formation following rhEPO may explain this finding. Therefore, Ro 50-3821 may provide important clinical advantages compared to unpegylated EPO. It can be administered in longer dosing intervals and has a lower risk of unfavorable immunological responses.

Recombinant human erythropoietin in the treatment of nonrenal anemia

Recombinant human erythropoietins (rhEPO) reliably increase hemoglobin levels in cancer patients experiencing chemotherapy-associated anemia. However, in patients with "anemia of cancer" not being treated with chemotherapy, rhEPO appears less effective. Recently, two studies have been broadly discussed which have raised concern on the concomitant use of erythropoietin and chemo- or radiation therapy in cancer patients. In addition, use of rhEPO is generally not considered cost-effective. Thus, the application of rhEPO should be limited to indications with proven clinical benefit. This review will provide an overview of the state of the art use of rhEPO in anemic patients and will discuss future developments.