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

Effects of chemotherapy on endogenous erythropoietin levels and the pharmacokinetics and erythropoietic response of darbepoetin alfa: a randomised clinical trial of synchronous versus asynchronous dosing of darbepoetin alfa.

The introduction of longer-acting erythropoietic agents into the practice of oncology has demanded an understanding of the interaction of chemotherapy with the pharmacokinetics and haematological effects of these erythropoietins. We report results of a randomised trial comparing the haematological effects of darbepoetin alfa, 6.75 mug/kg, administered once every 3 weeks to anaemic cancer chemotherapy patients on either an asynchronous (day 15) or synchronous (day 1) schedule relative to their every-3-week chemotherapy. A total of 81 patients were randomised and received the study drug (43 asynchronous; 38 synchronous). No difference was observed between groups in the primary endpoint of mean haemoglobin change after 6 weeks of therapy (P=0.45) and change scores were similar to those observed with standard weekly darbepoetin alfa therapy. In a subset of patients evaluated with intensive pharmacokinetic sampling, an increase in endogenous erythropoietin concentration (up to 4-fold) lasting approximately 1 week following chemotherapy administration was observed in both groups. Synchronous administration of darbepoetin alfa was associated with a 1.3-fold increase in the area under the darbepoetin alfa concentration-time curve compared with asynchronous administration. Our data suggest that darbepoetin alfa is effective administered every 3 weeks regardless of timing of administration with respect to chemotherapy and that receptor-mediated uptake by the erythron may be an important clearance mechanism for erythropoietic proteins.

Treatment of chemotherapy-induced anemia in breast cancer: results of a randomized controlled trial of darbepoetin alfa 200 microg every 2 weeks versus epoetin alfa 40,000 U weekly.

BACKGROUND: Current chemotherapy regimens for breast cancer result in high incidences of anemia, which can be treated with erythropoietic agents. The relative efficacy of darbepoetin alfa and epoetin alfa was explored in this phase II, open-label, randomized, multicenter trial in anemic patients with breast cancer receiving chemotherapy. PATIENTS AND METHODS: Patients were randomized at a 1:1 ratio to receive darbepoetin alfa 200 microg every 2 weeks (n = 72) or epoetin alfa 40,000 U weekly (n = 69) for < or = 16 weeks. Clinical and hematologic endpoints and validation of a novel patient satisfaction questionnaire for anemia treatment were evaluated for all patients randomized to receive > or = 1 dose of study drug. RESULTS: Baseline characteristics were generally similar between treatment groups. Mean changes in hemoglobin (Hb) level from baseline were similar at 1.9 g/dL for darbepoetin alfa and 1.7 g/dL for epoetin alfa. Hematopoietic responses (> or = 2 g/dL increase in Hb level from baseline or Hb level > or = 12 g/dL) were also similar between groups (88% for darbepoetin alfa and 81% for epoetin alfa). The proportions of patients who received a transfusion during treatment were 6% (95% CI, 0-11%) for darbepoetin alfa and 16% (95% CI, 7%-25%) for epoetin alfa. Most patients (67 patients receiving darbepoetin alfa [93%]; 61 patients receiving epoetin alfa [90%]) exhibited a clinically meaningful target Hb level > or = 11 g/dL. No differences in safety were observed. CONCLUSION: These results suggest that, in patients with breast cancer, darbepoetin alfa 200 microg every 2 weeks and epoetin alfa 40,000 U weekly result in comparable clinical outcomes for the treatment of chemotherapy-induced anemia.

A retrospective cohort study to assess the impact of therapeutic substitution of darbepoetin alfa for epoetin alfa in anemic patients with myelodysplastic syndrome.

Darbepoetin alfa and epoetin alfa are used to treat anemia in the undertreated population of patients with myelodysplastic syndrome (MDS). We implemented guidelines to switch anemic patients with MDS from epoetin alfa 40,000 U weekly to darbepoetin alfa 200 microg every 2 weeks and then conducted a retrospective cohort study of the initial 263 treated patients. Patients (> or = 18 years old, MDS diagnosis) were either previously treated with epoetin alfa (received 16 weeks of prior epoetin alfa and either switched to darbepoetin alfa or remained on epoetin alfa) or treatment-naive (no previous erythropoietin therapy and received only 1 agent for 16 weeks). Both major response and minor response based on the International Working Group criteria were calculated. The study was not powered to statistically compare treatment groups; values presented are for descriptive purposes only. Data from 244 patient records were included: 142 previous epoetin alfa patients (80 switched to darbepoetin alfa, 62 remained on epoetin alfa) and 102 naive patients (56 darbepoetin alfa, 46 epoetin alfa). Major response rates were similar between treatment groups in both the naive (46% for darbepoetin alfa, 35% for epoetin alfa) and previous epoetin alfa groups (26% for darbepoetin alfa, 17% for epoetin alfa). Overall response rates were 42%-76% across treatment groups. No differences in transfusions across groups were observed. Treatment of anemic patients with MDS with either darbepoetin alfa or epoetin alfa appeared to be effective. Whereas epoetin alfa was most frequently administered on a weekly basis, darbepoetin alfa was most frequently administered every 2 weeks, which may offer the benefit of convenience with its less frequent dosing.

A multicenter retrospective cohort study of practice patterns and clinical outcomes of the use of darbepoetin alfa and epoetin alfa for chemotherapy-induced anemia.

BACKGROUND: Darbepoetin alfa is the second erythropoietic protein to be approved for the treatment of chemotherapy-induced anemia (CIA). In the clinical setting, darbepoetin alfa can be administered less frequently than epoetin alfa with similar efficacy. Practice patterns and outcomes associated with the use of darbepoetin alfa and epoetin alfa in the clinical setting have not been reported. OBJECTIVE: This study compared practice patterns and clinical outcomes of the use of darbepoetin alfa and epoetin alfa for CIA at oncology practices in the United States. METHODS: This was a multicenter retrospective cohort study. Data were abstracted from the medical charts of consecutive patients who began darbepoetin alfa treatment between August 1 and October 4, 2002, or epoetin alfa treatment between April 1 and July 31, 2002, and were receiving concurrent chemotherapy. These data were used to determine the initial dose and dosing schedule, dose changes, and changes in hemoglobin concentrations after 4, 8, and 12 weeks of treatment, adjusted for red blood cell (RBC) transfusions, and the incidence of RBC transfusions over time. To minimize potential bias, the study protocol defined specific end points and prespecified analytic techniques for assessing clinical outcomes with the 2 agents. RESULTS: The records of 1391 patients from 16 community and hospital outpatient oncology clinics were abstracted. Of these, 1293 patients (93.0%) received only 1 erythropoietic agent (darbepoetin alfa, 735 [56.8%]; epoetin alfa, 558 [43.2%]); the remainder received both agents. In the patients who received darbepoetin alfa, most (553 [75.2%]) received an initial dosage of 200 microg q2wk. A similar proportion (414 [74.2%]) received epoetin alfa at an initial dosage of 40,000 U qwk. As these were the regimens for the majority of patients whose records were abstracted, the results reported here are for these patients. The dose was increased in 63 darbepoetin alfa recipients (11.4%) and 58 epoetin alfa recipients (14.0%) at a median of 7 weeks. After 12 weeks, the 2 groups had an identical mean imputed change from baseline in hemoglobin concentration (1.0 g/dL), and the incidence of RBC transfusions during treatment was also similar between groups (darbepoetin alfa, 44553 [8.0%]; epoetin alfa, 39414 [9.4%]). CONCLUSIONS: Darbepoetin alfa 200 microg q2wk was used as a standard regimen for CIA at the 16 US oncology practices participating in this study. It appeared to be as effective as epoetin alfa 40,000 U qwk, with a reduced frequency of dosing.

Assessing symptom burden using the M. D. Anderson symptom inventory in patients with chemotherapy-induced anemia: results of a multicenter, open-label study (SURPASS) of patients treated with darbepoetin-alpha at a dose of 200 microg every 2 weeks.

BACKGROUND: Patients with cancer who are receiving chemotherapy often experience chemotherapy-induced anemia (CIA), which is associated with symptoms that reduce quality of life. The M. D. Anderson Symptom Inventory (MDASI) is a brief, self-rating assessment scale that measures the severity of core symptoms and symptom interference with function. The current study used the MDASI to prospectively assess the correlation between hemoglobin and self-perceived cancer-related symptoms in a large patient population with CIA who were receiving darbepoetin-alpha at a dose of 200 mug every 2 weeks. METHODS: Eligible patients enrolled in this multicenter, open-label study were age > or =18 years, had a nonmyeloid malignancy, were receiving multicycle chemotherapy, and were anemic (hemoglobin < or = 11 g/dL). Hemoglobin was measured every 2 weeks; the MDASI was administered weekly. For hemoglobin-based endpoints, patients were stratified by baseline hemoglobin (< 10 g/dL or > or =10 g/dL). RESULTS: Of 2422 enrolled patients, 2401 received > or =1 dose of darbepoetin-alpha. Eighty percent of patients (95% confidence limit, 78-82 patients) achieved target hemoglobin levels (> or =11 g/dL) during the study. Patients with a baseline hemoglobin < 10 g/dL had a greater increase in hemoglobin, took longer to achieve the target hemoglobin, and received more red blood cell transfusions than patients with a baseline hemoglobin > or =10 g/dL. The percentage of patients with moderate to severe MDASI scores (> or =5 points) for fatigue, distress, loss of appetite, disturbed sleep, and interference with function was reduced during the study. Improvement in symptom burden was associated with an increase in hemoglobin concentration. CONCLUSIONS: Treatment with darbepoetin-alpha at a dose of 200 mug every 2 weeks is associated with improvement in symptom burden as measured by the MDASI, a simple tool that may improve symptom management for cancer patients with CIA.

Pharmacokinetic evaluation of darbepoetin alfa for the treatment of pediatric patients with chemotherapy-induced anemia.

BACKGROUND: Cancer patients undergoing chemotherapy often develop anemia, which can increase the risk for transfusions and fatigue. The recombinant erythropoiesis-stimulating agent darbepoetin alfa can effectively treat chemotherapy-induced anemia (CIA) in adults, but limited data are available regarding its use in pediatric cancer patients. The goals of this phase 1, open-label, uncontrolled study were to assess the pharmacokinetic profile and safety of darbepoetin alfa in pediatric patients with CIA. PROCEDURE: Pediatric patients with nonmyeloid malignancies and CIA received up to six doses of darbepoetin alfa 2.25 mcg/kg subcutaneously. After the first dose, the pharmacokinetic properties of darbepoetin alfa were assessed during a 14-day sampling period. All subsequent doses were given weekly with predose blood samples collected before study drug administration. RESULTS: After a single dose of darbepoetin alfa, the mean (SD) peak serum concentration was 10.5 (3) ng/ml, and the median time to peak concentration was 71.4 hr. Darbepoetin alfa exhibited a mean (SD) terminal half-life of 49.4 (32) hr. Upon repeated weekly administration, no evidence of darbepoetin alfa accumulation was observed though there was high intra- and inter-individual variability. In addition, darbepoetin alfa was well tolerated; some study patients experienced increases in hemoglobin. CONCLUSIONS: The pharmacokinetic profile of darbepoetin alfa indicated that it was slowly absorbed and exhibited a long terminal half-life in these pediatric study patients with CIA.

A randomized, controlled trial comparing darbepoetin alfa correction/maintenance dosing with weekly dosing for treating chemotherapy-induced anemia.

OBJECTIVE: To evaluate if a darbepoetin alfa correction/maintenance dosing regimen is non-inferior to a weekly regimen with respect to red blood cell transfusion requirements in patients with chemotherapy-induced anemia (CIA). RESEARCH DESIGN AND METHODS: In this randomized, active-controlled, double-blind phase 3 trial, CIA patients were randomized 1:1 to receive darbepoetin alfa in either a correction/maintenance schedule (4.5 microg/kg weekly for 4 weeks followed by 4.5 microg/kg every 3 weeks (Q3W)) or a weekly schedule (2.25 microg/kg weekly). The primary endpoint was the transfusion incidence during weeks 1-16. Non-inferiority was to be concluded if the upper limit of the 95% confidence interval (CI) of the difference in transfusion incidence between treatment groups was below 12.5%. Hematologic responses and safety profiles were also compared. RESULTS: Transfusion incidence (95% CI) during weeks 1-16 was 37% (32-42) and 38% (32-43) in the weekly and correction/maintenance groups, respectively. The difference (95% CI) in transfusions was 0.4% (-7.0 to 7.8), demonstrating non-inferiority between treatment groups. Similar percentages in both groups achieved and maintained hemoglobin in a target range of 11-13 g/dL and had clinically meaningful FACT-F score improvements. The median (range) time to hemoglobin response was 10 (1-17) weeks and 12 (2-17) weeks in the weekly and correction/maintenance groups, respectively. Both groups had similar safety profiles. CONCLUSIONS: A correction/maintenance schedule with its initial two-fold higher weekly dosing and subsequent Q3W dosing yielded outcomes similar to those observed with a weekly schedule. Although correction/maintenance dosing provided no incremental clinical benefit, Q3W dosing could provide benefits of convenience and facilitate patient compliance.

Efficacy and safety of every-2-week darbepoetin alfa in patients with anemia of cancer: a controlled, randomized, open-label phase II trial.

This randomized, controlled trial evaluated the effect of darbepoetin alfa on hospitalization days, transfusion requirements, hemoglobin levels, and fatigue in patients with anemia of cancer (AOC). Eligible patients were anemic (hemoglobin or=18 years old, and had not received chemotherapy or radiotherapy within 4 weeks of study screening. Patients were randomized 4:1 to receive darbepoetin alfa, 3.0 microg/kg every 2 weeks (Q2W) (n = 226), or observation only for 12 weeks (n = 59), followed by an optional 9 weeks of darbepoetin alfa, 3.0 microg/kg Q2W. Endpoints were compared between the two treatment arms at week 13. A planned interim analysis indicated that assumptions regarding hospitalization in the study design were incorrect, so the study was terminated early. Therefore, results for the primary endpoint should be interpreted cautiously. The hospitalization rate was similar (0.5 days) for both the darbepoetin alfa and observation groups (p = .73). Transfusion incidence (weeks 5-12) was significantly lower for darbepoetin alfa patients (8%) than for observation patients (22%) (p = .0092). By week 13, hemoglobin increased by 2.1 g/dl in patients receiving darbepoetin alfa, compared with 0.1 g/dl in the observation group p < .0001. Hemoglobin improvements were paralleled by an increase in Functional Assessment of Cancer Therapy-Fatigue score (mean change in score at week 13: darbepoetin alfa, 6.0; observation, 2.2; p < .05). Darbepoetin alfa Q2W can significantly improve hemoglobin levels and reduce transfusion requirements in patients with AOC, resulting in significant improvements in health-related quality of life.

A randomized, open-label, multicenter trial of immediate versus delayed intervention with darbepoetin alfa for chemotherapy-induced anemia.

The optimal hemoglobin concentration at which to initiate erythropoietic therapy for chemotherapy-induced anemia (CIA) is not well defined. This randomized, open-label, multicenter study evaluated the ability of darbepoetin alfa (300 microg every 3 weeks) to maintain hemoglobin levels > or =10 g/dl in patients with CIA (hemoglobin > or =10.5 g/dl and < or =12.0 g/dl) randomized 1:1 to an immediate-intervention group (received darbepoetin alfa immediately) or observation group (received darbepoetin alfa if hemoglobin fell to <10 g/dl). In 201 evaluable patients, there was a significant difference between the two groups in the Kaplan-Meier proportion of patients with a hemoglobin decrease to <10 g/dl during weeks 1-13 (test period) (primary endpoint): 29% for immediate-intervention patients versus 65% for observation patients. Sixty-four patients in the observation group received darbepoetin alfa (delayed-intervention subgroup). The Kaplan-Meier proportion of patients who received transfusions was lower in the immediate-intervention group than in the delayed-intervention subgroup (14% versus 31% for the test period; 17% versus 36% over the whole study). The target hemoglobin level (> or =11 g/dl) was achieved by a higher percentage of patients (crude percentage) in less time in the immediate-intervention group (94% in 2 weeks) than in the delayed-intervention subgroup (73% in 6 weeks); hemoglobin endpoints for the delayed-intervention subgroup were calculated from recalibrated study week 1 (the date patients first received darbepoetin alfa). For both groups, a higher mean change in hemoglobin from baseline led to a greater improvement in Functional Assessment of Cancer Therapy-Fatigue scores. In conclusion, immediate intervention resulted in a significantly lower proportion of patients who experienced a decline in hemoglobin, lower requirement for transfusions, and greater proportion of patients achieving and maintaining the target hemoglobin level.

Randomized, double-blind, active-controlled trial of every-3-week darbepoetin alfa for the treatment of chemotherapy-induced anemia.

BACKGROUND: In the United States, darbepoetin alfa (Aranesp) is often used to treat patients with chemotherapy-induced anemia using weekly or every-2-week administration schedules. In Europe, darbepoetin alfa is used either weekly or in every-3-week dosing. The every-3-week schedule can be synchronized with many chemotherapy regimens, resulting in fewer visits and reducing burden to patients, but the safety and efficacy of this regimen have not been clear. METHODS: A randomized, double-blind, double-dummy, active-controlled phase 3 trial was performed in 110 European centers. Eligible patients (age > or = 18 years) were anemic (hemoglobin level < 11 g/dL), had a nonmyeloid malignancy, and were to receive at least 12 weeks of chemotherapy. Patients were randomly assigned 1:1 to darbepoetin alfa treatment every 3 weeks (500-microg dose) or weekly (2.25-microg/kg) for 15 weeks. We compared red blood cell transfusion incidence among the two arms from week 5 to the end of the treatment phase using a noninferiority study design. Noninferiority was determined if the upper limit of the 95% confidence interval (CI) for the difference in blood transfusions between groups, calculated using Kaplan-Meier methods, did not exceed 12.5%, a margin based on previous placebo-controlled studies. RESULTS: A total of 705 patients were randomly assigned, and 672 remained in the study at week 5. Fewer patients in the every-3-week arm than in the weekly arm received blood transfusions from week 5 to the end of the treatment phase (unadjusted Kaplan-Meier estimates = 23% versus 30%, difference = -6.8%; 95% CI = -13.6 to 0.1). Percentages of patients achieving the target hemoglobin level (> or = 11 g/dL, consistent with evidence-based practice guidelines) were 84% (every 3 weeks) and 77% (weekly). The frequency of cardiovascular/thromboembolic adverse events was 8% in both groups, and safety was comparable. CONCLUSIONS: Patients with chemotherapy-induced anemia can safely and effectively be treated with 500 microg of darbepoetin alfa every 3 weeks.

Randomized comparison of every-2-week darbepoetin alfa and weekly epoetin alfa for the treatment of chemotherapy-induced anemia: the 20030125 Study Group Trial.

PURPOSE: Chemotherapy-induced anemia is widely treated in the United States with darbepoetin alfa (DA) or epoetin alfa (EA). This noninferiority study systematically compares efficacy and safety of DA and EA using common doses and schedules used in clinical practice. METHODS: Patients had a diagnosis of nonmyeloid malignancy with > or = 8 weeks of planned chemotherapy, age >or = 18 years, and anemia (hemoglobin < or = 11 g/dL). Patients were randomly assigned 1:1 to DA 200 microg every two weeks (Q2W) or EA 40,000 units every week (QW) for up to 16 weeks with identical dose adjustment rules. Efficacy was assessed by the incidence of RBC transfusion (Kaplan-Meier estimate). The definition of noninferiority was that the upper 95% CI limit of the observed difference in RBC transfusions between groups was less than 11.5%; this noninferiority margin was based on the treatment effect observed in placebo-controlled EA studies. RESULTS: Of 1,220 patients randomly assigned, 1,209 received > or = one dose of the study drug. Common tumor types were lung (26%), breast (21%), and gastrointestinal (18%). Transfusion incidence from week 5 to the end of the treatment phase (the primary end point) was 21% in the DA group and 16% in the EA group; noninferiority was concluded because the upper 95% CI limit of the difference between groups (10.8%) was below the prespecified noninferiority margin. Sensitivity analyses using alternate statistical methods and analysis sets yielded similar results. Hemoglobin, quality of life, and safety end points further support equivalency of the erythropoietic therapies. CONCLUSION: This large, phase III study demonstrates comparable efficacy of DA Q2W and EA QW. Less frequent dosing offers potential benefits for patients, caregivers and health care providers.

A randomized comparison of every-2-week darbepoetin alfa and weekly epoetin alfa for the treatment of chemotherapy-induced anemia in patients with breast, lung, or gynecologic cancer.

An important clinical question is the relative efficacy of the most common dosages of darbepoetin alfa (Aranesp; Amgen Inc.; Thousand Oaks, CA) 200 microg every 2 weeks (Q2W) and epoetin alfa (Procrit; Ortho Biotech Products, LP; Raritan, NJ) 40,000 U weekly (QW) for the treatment of chemotherapy-induced anemia. We designed three concurrent randomized, open-label, multicenter, identical trials (with the exception of tumor type criteria of breast, gynecologic, or lung cancer) of darbepoetin alfa and epoetin alfa in patients with chemotherapy-induced anemia to validate the Patient Satisfaction Questionnaire for Anemia (PSQ-An) treatment tool and to compare the efficacies and safety profiles of these two agents. In each trial, patients were randomized 1:1 to receive either darbepoetin alfa at a dose of 200 microg Q2W or epoetin alfa at a dose of 40,000 U QW for up to 16 weeks. The PSQ-An was assessed for validity, feasibility, and reliability. Secondary clinical endpoints were analyzed using the primary analysis set. Both individual trial analyses and a protocol-specified combined analysis of data from all three trials were conducted. Overall, 312 patients (157 darbepoetin alfa; 155 epoetin alfa) were randomized and received study drug. Baseline characteristics were similar in both treatment groups in each trial and overall. The PSQ-An was valid, feasible, and reliable. In general, no difference between treatment groups was observed for hemoglobin- and transfusion-based endpoints in each individual trial or in the combined analysis. From exploratory analyses, achievement and maintenance of a hemoglobin target range (11-13 g/dl) were similar in both groups. No differences in safety were observed. With the PSQ-An, formal comparisons of the impact of anemia therapies on patients and caregivers can be made in future prospective studies. Further, darbepoetin alfa (200 microg Q2W) and epoetin alfa (40,000 U QW) appear to achieve comparable clinical and hematologic outcomes.