Preference for monthly darbepoetin alfa dosing in patients with chronic kidney disease not receiving dialysis

ABSTRACT

Objective: To determine patient preference for once-weekly Epoetin alfa versus once-monthly (QM) darbepoetin alfa in patients with chronic kidney disease (CKD) not receiving dialysis.

Methods: AMPS (Aranesp Monthly Preference Study) consisted of two studies of similar design, each with a 2-week screening/baseline period, a 20-week QM darbepoetin alfa dosing period, and an 8-week follow-up period. Patients aged ≥18 years had a nephrologist-reported diagnosis of CKD but were not receiving dialysis, and were required to have at least two hemoglobin levels within 10–12?g/dL and to have been receiving a stable dose (< 25% change) of once-weekly or once- every-other-weekly Epoetin alfa for at least 8 weeks. At week 21, patients could continue on QM darbepoetin alfa or revert back to their previous Epoetin alfa regimen. The primary analysis assessed patient preference at week 21 for QM darbepoetin alfa versus previous onceweekly Epoetin alfa.

Results: AMPS enrolled 442 patients: 54% were female, 67% were Caucasian, and mean (SD) age was 68.3 (13.5) years. At week 21, 346 patients remained on study. Of the patients converted from once-weekly Epoetin alfa, 86% (138/161) preferred darbepoetin alfa QM, and of all patients who expressed a preference, regardless of previous Epoetin alfa dosing frequency, 96% (305/319) preferred QM darbepoetin alfa. Mean (SD) hemoglobin at week 29 of the study was similar to mean hemoglobin at baseline (for those who completed the study and were receiving QM darbepoetin alfa at week 29: 11.2 [1.1]?g/dL at week 29 versus 11.4 [0.7]?g/dL at baseline). QM darbepoetin alfa was well tolerated.

Conclusion: These data show that the majority of study patients preferred QM darbepoetin alfa to more frequent Epoetin alfa, and that QM darbepoetin alfa maintained hemoglobin levels at week 29 and was well tolerated over the study period. The single-item questionnaire could be a potential limitation of this study and further investigation with a multi-question instrument may be helpful in confirming these results.     

Use and cost of erythropoiesis-stimulating agents in patients with cancer

ABSTRACT

Objective: To compare the baseline characteristics, episodes of care, and cost of erythropoiesis-stimulating agents among cancer patients in a US managed-care population.

Research design and methods: Retrospective analysis of administrative claims data. Episodes of care for patients with cancer receiving erythropoiesis-stimulating agents between January 1, 2004 and January 17, 2006 included all claims for erythropoiesis-stimulating agents with ≤42 days’ gap between claims, plus the duration of therapeutic benefit based on median days between consecutive doses.

Main outcome measures: Main outcome measures were average weekly dose of erythropoiesis-stimulating agents and costs of therapy.

Results: A total of 15?007 eligible episodes of care (darbepoetin alfa, 7769 episodes [5587 patients]; epoetin alfa 7238 episodes [5157 patients]) were identified. Fewer claims were observed per episode of care for darbepoetin alfa than for epoetin alfa (mean [SD] 3.7 [4.1] vs. 5.3 [6.4]). The median time between consecutive claims was 15 days (darbepoetin alfa) and 8 days (epoetin alfa). The mean (SD) weekly doses were 105 (56)?μg (darbepoetin alfa) and 34?242 (28173) U (epoetin alfa), a dose-comparison ratio of 326?:?1.

Dose-comparison ratios were sensitive to assumptions about duration of clinical benefit.

The mean (95% CI) weekly costs were significantly lower for darbepoetin alfa ($560 [553–567]) than for epoetin alfa ($645 [630–659], p < 0.0001) when duration of clinical benefit was considered.

Conclusions: Significant differences characterize patterns of use of erythropoiesis-stimulating agents. Duration of therapeutic benefit is an important variable in comparing darbepoetin alfa with epoetin alfa; incorporation of this variable in analyses of costs of therapy may have notable effects on calculated treatment costs. Limitations of the study include the potential for database errors or omissions, lack of detailed disease data, and lack of adjustment for differences in the ages and comorbidities of patients.     

Improved haemoglobin concentrations with IV darbepoetin alfa--case studies of haemodialysis patients

This paper presents two case histories of patients receiving intravenous (IV) darbepoetin alfa for the treatment of anaemia in chronic renal failure. The paper sets these cases against the general clinical picture of patients receiving intravenous darbepoetin alfa in our renal unit.     

The advantages of intravenous renal anaemia treatment in an undernourished patient with chronic kidney disease

SUMMARY

The subcutaneous (SC) treatment of renal anaemia in undernourished patients has potential limitations. In this case report we demonstrate the value of intravenous (IV) darbepoetin alfa in such a patient who experienced difficulty tolerating SC recombinant human erythropoietin (rHuEPO) therapy due to severe malnutrition. Intravenous treatment of renal anaemia in a malnourished patient is preferred because the absence of SC fat makes SC administration difficult. In such patients, darbepoetin alfa is the treatment of choice as it is administered less frequently than other erythropoietic therapies and yis more effective at maintaining target haemoglobin (Hb) concentrations. In contrast to rHuEPO, darbepoetin alfa also has the additional advantage of bioequivalent IV and SC dose requirements.     

The relative dosing of epoetin alfa and darbepoetin alfa in chronic kidney disease

ABSTRACT

Objective: The purpose of this study was to review and analyze current research to evaluate the dose ratio of epoetin alfa and darbepoetin alfa for the treatment of anemia in chronic kidney disease (CKD) and to identify determinants of the variation in epoetin alfa: darbepoetin alfa dose ratios across studies.

Methods: A systematic review of the literature for comparative switch and non-switch studies of epoetin alfa and darbepoetin alfa treatments in CKD for the period 2000–2005 was performed. Two reviewers independently assessed the quality of the information. Data on the study design and outcomes were collected for each selected study. The dose ratio from epoetin alfa to darbepoetin alfa was calculated for each study, and the results were reported stratified by study characteristics. To control for differences in study design and characteristics that could explain the variability in the relative dosages of the two agents across studies, multivariate regression analysis was conducted. Based on these results, a dose conversion ratio for Canada was estimated.

Results: A total of 21 studies involving 16?378 patients exposed to epoetin alfa or darbepoetin alfa in CKD were identified. Univariate analysis of the dose ratios indicated a mean dose ratio of 217:1 (IU of epoetin alfa:µg of darbepoetin alfa). Results from the multivariate analysis demonstrated that the study design (i.e., switch study versus straight comparison studies) and geographical coverage (i.e., United States) affected the results. Based on the multivariate analysis, the dose conversion ratio between epoetin alfa and darbepoetin alfa for Canada was 169:1.

Conclusions: Despite limitations associated with switching studies and the limited total number of studies available, this systematic review based on aggregated results provides further evidence to the clinical community that the dose conversion ratio for epoetin alfa:darbepoetin alfa in CKD patients in Canada is approximately 169:1. At that ratio, treatment with epoetin alfa is 11–18% cheaper than treatment with darbepoetin alfa in Canada.     

Darbepoetin alfa.

Darbepoetin alfa is a novel erythropoiesis-stimulating protein developed for the treatment of anaemia associated with chronic kidney disease. In single-dose studies in patients undergoing dialysis, the mean terminal half-life for intravenous darbepoetin alfa was approximately 3-fold longer than for intravenous recombinant human erythropoitin (r-HuEPO, epoetin alfa; 25.3 vs 8.5 hours). The mean terminal half-life after subcutaneous administration of darbepoetin alfa was 48.8 hours. In randomised nonblind trials in patients undergoing dialysis, darbepoetin alfa (0.45 pg/kg) given once weekly for the correction of anaemia increased haemoglobin (Hb) levels to a similar extent as darbepoetin alfa three times weekly or r-HuEPO two or three times weekly. A double-blind, randomised clinical trial reported that switching patients from a three-times weekly regimen of r-HuEPO to once weekly darbepoetin alfa with additional placebo twice weekly (all intravenously) maintained Hb levels between 9.0 and 13.0 g/dl to a similar extent as continued treatment with r-HuEPO three times weekly. In a randomised nonblind study, r-HuEPO-naive patients with chronic renal insufficiency received either subcutaneous darbepoetin alfa once weekly or r-HuEPO twice weekly. 93% of patients receiving darbepoetin alfa and 92% of patients receiving r-HuEPO achieved a Hb increase of > or = 1.0 g/dl from baseline and the mean increase in Hb level over the initial 4 weeks was similar for both treatments. The number and frequency of adverse events, withdrawals and deaths reported in clinical trials did not differ between patients receiving darbepoetin alfa and patients receiving r-HuEPO. There have been no reports of immune responses to darbepoetin alfa in 1534 patients receiving treatment for up to 2 years.     

Anemia treatment with Q2W darbepoetin alfa in patients with chronic kidney disease naïve to erythropoiesis-stimulating agents*

ABSTRACT

Objective: To evaluate the efficacy and safety of darbepoetin alfa dosed every-other-week (Q2W) to treat anemia in subjects with chronic kidney disease (CKD), not receiving dialysis, who were naïve to erythropoiesis-stimulating agent (ESA) therapy.

Research design and methods: This was an open-label, multicenter, single-arm study enrolling ESA-naïve CKD subjects with baseline hemoglobin (Hb)?<?11.0?g/dL. Q2W darbepoetin alfa treatment was initiated at a dose of 0.75?µg/kg and titrated to achieve and maintain Hb levels at 11.0–13.0?g/dL. Treatment was administered from week 1 to week 19.

Main outcome measures: The primary endpoint was the proportion of subjects who achieved Hb?≥?11?g/dL at any study visit, except in week 1. Hb levels, darbepoetin alfa dose, and safety were also assessed.

Results: Of the 128 subjects who received at least one dose of darbepoetin alfa and of the subjects who completed the study, 118 (92%) and 112 (97%), respectively, achieved a Hb?≥?11?g/dL in a median time of 5 weeks. Median darbepoetin alfa dose at week 1 and at the time of achieving a Hb?≥?11?g/dL were 60 and 80?µg, respectively. Darbepoetin alfa was well-tolerated, and short-term adverse events were consistent with those expected in CKD subjects.

Conclusions: This study demonstrates that de novo Q2W darbepoetin alfa was effective in correcting and maintaining Hb levels in ESA-naïve subjects with CKD who were not receiving dialysis. Study limitations, including lack of a control arm for the study and multiple race information for subjects, must be considered in interpreting the results.

Trial registration: ClinicalTrials.gov identifier: NCT00112008.     

A randomised,cross-over study comparing injection site pain with subcutaneous epoetin beta and subcutaneous darbepoetin alfa in patients with chronic kidney disease*

ABSTRACT

Objective: To compare injection site pain of subcutaneous (sc) epoetin beta and darbepoetin alfa in adult patients with chronic kidney disease.

Research design and methods: This was a multi-centre, randomised, two-arm, single-blind, cross-over study. Patients were randomised to receive weekly sc darbepoetin alfa 30?μg or weekly sc epoetin beta 6000?IU for 2 weeks and were then crossed over to the alternative treatment for 2 weeks. Injection site pain was assessed using a 10?cm ungraduated visual analogue scale (0?=?no pain, 10?=?worst pain) and a six-point verbal rating scale. Patient preference for treatment was also assessed.

Trial registration: http://clinicaltrials.gov/(NCT00377481).

Results: All randomised patients (N?=?48) completed the study. The sample comprised 29 chronic kidney disease patients (Stage 3 or Stage 4), 11 peritoneal dialysis patients and 8 renal transplant patients. Patients perceived significantly less pain with epoetin beta than darbepoetin alfa, using the visual analogue scale (relative pain score?=?2.75, darbepoetin alfa:epoetin beta, 95% CI: 1.85, 4.07; p?<?0.0001) and the verbal rating scale (median: 0.5, 95% CI: 0.5, 1.0 vs. median: 1.5, 95% CI: 1.0, 2.0; p?<?0.0001). Epoetin beta was preferred by significantly more patients (65%) than darbepoetin alfa (10%) (p?<?0.001); 25% of patients reported no preference.

Conclusions: Limitations included lack of an epoetin alfa comparator and limited blinding (patients were blinded to treatment, however, an unblinded nurse administered treatment). We show that sc injection of epoetin beta is significantly less painful than darbepoetin alfa and patient preference for epoetin beta confirms that the difference is clinically meaningful.     

Darbepoetin alfa: a novel erythropoiesis-stimulating protein

Darbepoetin alfa is a novel erythropoiesis-stimulating protein developed for the treatment of anemia. It is a hyperglycosylated analog of recombinant human erythropoietin with the same mechanism of action as erythropoietin, but with a three-fold longer terminal half-life after intravenous administration than recombinant human erythropoietin and the native hormone both in animal models and in humans. Clinical studies in patients with chronic renal failure either receiving or not receiving dialysis have shown that darbepoetin alfa is equivalent to recombinant human erythropoietin in terms of increases in hemoglobin concentration, percentage of patients achieving target hemoglobin concentration and average time to reach target hemoglobin concentration, although darbepoetin alfa is administered less frequently (once weekly or every other week). Clinical trials in cancer patients either receiving or not receiving chemotherapy have demonstrated that darbepoetin alfa is safe and effective in alleviating anemia at dose intervals of once every 1, 2 or 3 weeks, and results suggest that it may achieve greater and more rapid responses than recombinant human erythropoietin in cancer patients. Furthermore, an improvement in health-related quality of life has been observed in association with anemia correction using darbepoetin alfa therapy in these patients. Darbepoetin alfa has been approved for intravenous and subcutaneous administration by the European Commission and the FDA for the treatment of anemia in patients with chronic renal failure. Additionally, this product was recently approved by the FDA for the treatment of anemia in patients with nonmyeloid malignancies where anemia is due to the effect of concomitantly administered chemotherapy. The recommended starting dose in chronic renal failure patients is 0.45 microg/kg once weekly for both intravenous and subcutaneous administration, with subsequent titration based on the hemoglobin concentration. In cancer patients, the recommended starting dose is 2.25 microg/kg once weekly by subcutaneous injection and subsequent titration. The adverse event profile of darbepoetin alfa is similar to that of recombinant human erythropoietin in both settings. There are no reports of antibody formation associated with darbepoetin alfa in chronic renal failure patients, and three cases of antibody formation, with neutralizing activity in one of the cases, have been reported in cancer patients. However, no cases of antibody-mediated pure red cell aplasia have been reported. The longer half-life of darbepoetin alfa, together with a similar efficacy and safety profile, confers the clinical advantage over recombinant human erythropoietin of allowing a less frequent dosing (once weekly or every other week versus one to three times weekly in renal patients), thus reducing health-care utilization and probably improving patient compliance.     

Subcutaneous injection pain with C.E.R.A., a continuous erythropoietin receptor activator,compared with darbepoetin alfa

ABSTRACT

Objective: This study assessed injection site pain following subcutaneous (SC) administration with a continuous erythropoietin receptor activator (C.E.R.A.), compared with darbepoetin alfa in healthy adults.

Methods: In a randomized, placebo-controlled, single-centre, single-blind, three-way crossover study, subjects received one of six treatment sequences (ABC/ACB/BAC/BCA/CBA/CAB) involving SC injection of (A) C.E.R.A. 50?μg, (B) darbepoetin alfa 50?μg, or (C) placebo on days 1, 29, and 57. An initial pilot phase (n = 12) was used to determine the sample size for the confirmatory phase (n = 72), and data were combined for the final analysis (n = 84).

Main outcome measures: The primary endpoint was pain on the 100?mm visual analog scale (VAS) immediately after dosing. Secondary endpoints included VAS at 1 hour after dosing and pain on the six-point verbal rating scale (VRS) immediately and at 1 hour after dosing.

Results: C.E.R.A. was associated with significantly less pain immediately after SC injection compared with darbepoetin alfa: least squares mean VAS 21.5 (95% confidence interval [CI]: 17.5, 25.5) versus 33.4 (95% CI: 28.4, 38.4) (?p < 0.0001). Incidence of pain on the VRS was lower with C.E.R.A. compared with darbepoetin alfa immediately after dosing (?p < 0.0001). One hour after administration, most subjects had no VRS pain. A study limitation is the small sample size and the findings need to be confirmed in a large trial of chronic kidney disease patients.

Conclusions: SC injection with C.E.R.A. is significantly less painful than SC darbepoetin alfa in healthy adults. Treatment of anemia in chronic kidney disease with SC injection of C.E.R.A. may provide a lower pain burden compared with darbepoetin alfa.     

Randomized,double-blind,placebo-controlled trial of every-3-week darbepoetin alfa 300 micrograms for treatment of chemotherapy-induced anemia

ABSTRACT

Objective: Darbepoetin alfa is effective in treating chemotherapy-induced anemia (CIA). Administration of subcutaneous darbepoetin alfa every 3 weeks (Q3W) could simplify treatment through synchronization with common Q3W chemotherapy regimens. We report results from a multicenter, randomized, double-blind, placebo-controlled, phase 3 trial evaluating the efficacy and safety of fixed-dose Q3W darbepoetin alfa in patients with a wide variety of tumor types who experienced CIA.

Research design and methods: Patients aged?≥?18 years with anemia (hemoglobin <11?g/dL) being treated for nonmyeloid malignancy were randomized 1:1 to receive darbepoetin alfa 300?μg (n?=?193) or placebo (n?=?193) subcutaneously Q3W from weeks 1 to 13 in this 16-week study. Doses could be adjusted per prespecified rules.

Main outcome measures: The primary endpoint was the proportion of patients who received ≥1 red blood cell (RBC) transfusion between week 5 and the end of the treatment period (EOTP). The study also analyzed the proportions of patients achieving a hemoglobin concentration ≥11?g/dL and subsequently maintaining hemoglobin levels above 11?g/dL, and the change in hemoglobin concentration over time.

Results: The proportion of patients requiring RBC transfusions between week 5 and EOTP was significantly lower in the darbepoetin alfa-treated group than in the placebo-treated group (24 vs. 41% of patients, a 16.3% difference, p?<?0.001). There were no differences between the two treatment arms in quality-of-life measures. Cardiovascular/thromboembolic adverse events were uncommon and were not associated with increases in hemoglobin levels. Study limitations suggest caution in the interpretation of these results: transfusions, the primary endpoint, were recommended but not required if hemoglobin concentrations were ≤8.0?g/dL, and protocol deviations (primarily dosing errors) occurred in approximately one-half of the patients in both treatment groups.

Conclusions: In this study, fixed-dose Q3W darbepoetin alfa appeared to be well-tolerated and effective for the treatment of CIA.

Trial registration: ClinicalTrials.gov identifier: NCT00110955.     

The association of darbepoetin alfa with hemoglobin and health-related quality of life in patients with chronic kidney disease not receiving dialysis

ABSTRACT

Objective: Anemia of chronic kidney disease (CKD) decreases patients’ health-related quality of life (HRQoL). The objective of this subanalysis was to determine the effect of every-other-week (Q2W) darbepoetin alfa on hemoglobin (Hb) levels and HRQoL measures in subjects with CKD who are naïve to erythropoiesis-stimulating agents (ESAs).

Methods: STAAR was a 52-week, multicenter, single-arm study. Subject inclusion criteria included: ≥?18?years of age and creatinine clearance ≤?70?mL/min or estimated glomerular filtration rate ≤?60?mL/min/1.73 m² but not receiving dialysis. Subjects included in this subanalysis were previously naïve to ESAs, had Hb <?11?g/dL, were initiated on subcutaneous Q2W darbepoetin alfa to achieve a Hb level not to exceed 12?g/dL, and had responses to at least one question on the KDQOL-CRI forms administered at baseline, week 12, and week 52.

Results: Of 911 ESA-naïve subjects enrolled in the study, 277 (30.4%) were included in this subanalysis. The majority of subanalysis subjects were Caucasian (63.2%) and/or women (54.5%). Mean Hb concentrations and all KDQOL-CRI scores improved significantly between baseline and week 12 (?p < 0.0001), and were maintained until week 52. Darbepoetin alfa was well tolerated.

Conclusions: Darbepoetin alfa initiated Q2W achieved and maintained Hb targets, and significantly improved and maintained HRQoL in study subjects with CKD. Limitations of the study must be considered when extrapolating these results to assess the benefits of treatment on HRQoL in the general CKD population.     

Pharmacokinetics of darbepoetin alfa after intravenous or subcutaneous administration in patients with non-myeloid malignancies undergoing chemotherapy

BACKGROUND AND OBJECTIVE: The pharmacokinetics of darbepoetin alfa after intravenous (IV) administration in the oncology setting have not been previously reported. The objective of this study was to evaluate the pharmacokinetics of IV or subcutaneous (SC) darbepoetin alfa in patients with non-myeloid malignancies undergoing multicycle chemotherapy. METHODS: Fifty-six patients (haemoglobin 相似文献   

Current practice of darbepoetin alfa in the management of haemoglobin levels in cancer patients undergoing chemotherapy – data from the CHOICE study

Abstract

Objective:

To evaluate adherence to European Organisation for Research and Treatment of Cancer (EORTC) and European Summary of Product Characteristic (SmPC) guidance on recommended haemoglobin (Hb) values in routine clinical practice use of darbepoetin alfa (DA) in cancer patients internationally.     

Darbepoetin alfa: in patients with chemotherapy-related anaemia

Darbepoetin alfa, novel erythropoiesis stimulating protein closely related to human erythropoietin, has been developed for the treatment of chemotherapy-related anaemia in patients with non-myeloid malignancies. In three 12-week, phase II studies in patients with cancer and chemotherapy-related anaemia, subcutaneous darbepoetin alfa, administered in once-weekly or 2-, 3- or 4-weekly regimens, dose-dependently increased the mean haemoglobin levels. In a randomised, double-blind, phase III study in 320 patients with lung cancer and chemotherapy-related anaemia, recipients of subcutaneous darbepoetin alfa 2.25 micro g/kg once weekly, received red blood cell (RBC) transfusion approximate, equals 2-fold less frequently than placebo recipients (p < 0.001). In the same study, patients receiving darbepoetin alfa also received fewer standard units of RBC for transfusion and had greater haematopoietic response rate than placebo recipients (both p < 0.001). Subcutaneous darbepoetin alfa 2.25 micro g/kg once weekly also reduced patient-reported fatigue (assessed by a quality-of-life questionnaire) [p = 0.019 vs placebo]. black triangle Darbepoetin alfa was generally well tolerated in clinical trials. The most frequent darbepoetin alfa-related adverse events were: body oedema, arthralgia and skin rash.     

Evaluation of the US Oncology Network's recommended guidelines for therapeutic substitution with darbepoetin alfa 200 microg every 2 weeks in both naïve patients and patients switched from epoetin alfa

STUDY OBJECTIVE: To evaluate the efficacy of darbepoetin alfa 200 microg subcutaneously every 2 weeks after therapeutic substitution for epoetin alfa. DESIGN: Retrospective multicenter chart review. SETTING: Three US Oncology-affiliated outpatient sites. PATIENTS: Three hundred thirty anemic patients with nonmyeloid malignancies, of whom 174 had been treated previously with epoetin alfa (switched group) and 156 had not been treated recently with epoetin alfa (naive group). INTERVENTIONS: Therapeutic substitution with darbepoetin alfa was started according to the US Oncology Pharmacy and Therapeutics Committee's recommended dosing guidelines: anemic patients with cancer received a starting dosage of darbepoetin alfa 200 microg every 2 weeks regardless of whether or not they had previously received epoetin alfa. Hematologic and darbepoetin alfa usage data were abstracted from consecutive medical records dated from May 2002-March 2003. MEASUREMENTS AND MAIN RESULTS: Median exposure to darbepoetin alfa was 10 weeks (25th quartile 6 wks, 75th quartile 17 wks) and 10 weeks (25th quartile 5 wks, 75th quartile 18 wks) for the naive and switched groups, respectively. The week before the switch to darbepoetin alfa, the 174 patients receiving epoetin alfa were administered the following weekly doses: less than 40,000 U (9%), 40,000 U (50%), or 45,000-90,000 U (41%). Mean hemoglobin level increased from baseline (wk 0) in both the naive and switched groups. The proportion of patients receiving a red blood cell transfusion in the darbepoetin alfa treatment phase was low (15% in each group). No variation in transfusion rates was observed across weight categories in patients who received a fixed dosage of darbepoetin alfa. Darbepoetin alfa was well tolerated. A detailed usage algorithm was validated by these results and is being used in these three US Oncology-affiliated practices. CONCLUSION: A darbepoetin alfa starting dosage of 200 microg subcutaneously every 2 weeks administered according to US Oncology-recommended dosing guidelines is effective in treating chemotherapy-induced anemia in both epoetin alfa-naive patients and those switched from epoetin alfa.     

Darbepoetin alfa: an effective treatment with flexible and simplified dosing for anemia in patients with cancer

Anemia is common in patients with cancer or myelodysplastic syndrome. Erythropoietic therapy offers an effective way to manage anemia by increasing hemoglobin levels, decreasing transfusion requirements, and alleviating symptoms. We reviewed data showing the feasibility and effectiveness of treatment with the erythropoiesis-stimulating protein darbepoetin alfa at extended dosing intervals to treat anemia in patients with cancer receiving multicycle chemotherapy. We also explored the darbepoetin alfa's potential for treating anemia in patients with myelodysplastic syndrome. Data from clinical studies and drug therapy evaluations confirm that darbepoetin alfa administered weekly, every 2 weeks, and every 3 weeks corrects and maintains hemoglobin levels in patients with chemotherapy-induced anemia. In addition, the data demonstrate that both weight-based and fixed dosing with darbepoetin alfa are effective, and that early intervention to treat anemia has clinical benefits. Darbepoetin alfa also is an effective treatment for anemia in patients with cancer not receiving chemotherapy, at extended dosing intervals of at least 3 weeks. Extended dosing for anemia treatment can provide benefits for patients, caregivers, and clinicians because it reduces the number of clinic visits needed and permits synchronizing anemia treatment with chemotherapy cycles. Data from recent studies suggest that darbepoetin alfa is effective for treating anemia in patients with myelodysplastic syndrome; this potential use is being investigated further in ongoing studies. Thus, darbepoetin alfa is an attractive therapy option for patients with chemotherapy or cancer-induced anemia. It allows increased flexibility and simplified dosing and may offer some benefit in the treatment of anemia in patients with myelodysplastic syndrome.     

Validation of the BIACORE 3000 platform for detection of antibodies against erythropoietic agents in human serum samples

SUMMARY

Objective: To develop a validated BIACORE immunoassay for the detection and characterization of serum antibodies with specificity for erythropoietic molecules (e.g. darbepoetin alfa).

Methods: New Zealand White rabbits (n?=?8) were immunized by an intramuscular injection of darbepoetin alfa/adjuvant at 0,4,6, and 8 weeks. Serum was collected for 6 weeks after final injection and pooled for affinity purification. Antibody immunoassay measurements were performed using a BIACORE 3000 with darbepoetin alfa immobilized to the biosensor surface. Human serum samples were spiked with the affinity-purified rabbit antibody to develop and validate the BIACORE immunoassay.

Results: The assay was shown to be stable through 180 sample/regeneration cycles and had a threshold of 45.8 response units. The validated limit of detection was 0.40|ig/ml in 100% human serum. The method was robust, with variability not

exceeding a 20% coefficient of variation, well within acceptable limits for typical immunoassays.

Conclusion: All protein-based therapeutics have a potential for immunogenicity, and antibodies raised against these molecules may have important clinical sequelae. The biotechnology and pharmaceutical industries are challenged to address this potential by developing robust analytical platforms to detect and characterize antibodies directed against therapeutic proteins in clinical specimens. Traditionally, radioimmune precipitation assays and/or enzyme-linked immunoassays (ELISAs) are used for primary detection of host immune response; however, the BIACORE platform may be better suited for this purpose in many instances. This platform represents a robust tool that should be considered for the detection and characterization of antibodies directed against protein-based therapeutics.     

Darbepoetin alfa: new indication/new dosage. No proven advantage in chemotherapy-induced anaemia

(1) Current treatments for anaemia in patients receiving cancer chemotherapy include blood transfusion and epoetin alfa and beta. These epoetins correct anaemia in 40% to 65% of patients and reduce the number of patients who require transfusions during the second and third months of treatment by 12-35% in absolute terms. (2) Darbepoetin alfa is slightly more glycosylated than epoetin alfa and beta. It is no more effective than these two drugs in chronic renal failure. Darbepoetin alfa is now approved for the treatment of anaemia in patients who are receiving chemotherapy for non myeloid malignancies. (3) Two placebo-controlled dose-finding studies and two placebo-controlled trials involving nearly 1000 patients in total have shown that darbepoetin alfa decreases the number of transfused patients by 17-25% in absolute terms, and that it probably reduces fatigue. However, one-quarter of patients receiving darbepoetin were nonetheless transfused. (4) In the absence of reliable comparisons, there is no firm evidence that darbepoetin alfa is more effective than other epoetins. (5) According to relatively imprecise company reports, darbepoetin alfa increased the risk of thromboembolic events during clinical trials (6% versus 3%), including pulmonary embolism (1.3% versus 0%); the company also states that darbepoetin alfa does not increase the risk of arterial hypertension, a classical effect of epoetin that is mentioned in the summary of product characteristics (SPC). Placebo-controlled trials and dose-finding studies show no impact on the outcome of cancer, but follow-up is limited and a negative effect cannot be ruled out. The company states that no cases of erythroblastopenia have occurred among more than 70 000 treated patients. (6) According to the SPC, darbepoetin alfa can be given once a week. However, the optimal epoetin dosing schedule is unknown. Epoetin therapy takes several weeks to correct anaemia, whereas transfusion is immediately effective. (7) In practice, darbepoetin alfa seems a little easier to administer than epoetin alfa or beta, but the advantages and disadvantages of these drugs as compared with blood transfusion are not entirely clear.     

A final analysis from the CHOICE study examining darbepoetin alfa use for chemotherapy-induced anaemia in current European clinical practice

Abstract

Objectives:

The CHOICE study was a prospective, multicentre, observational study designed to assess the level of adherence in current clinical practice to the European product label and the EORTC guidelines for the treatment of chemotherapy-induced anaemia with darbepoetin alfa (DA).