The Oncologist, Vol. 10, No. 8, 642-650, September 2005; doi:10.1634/theoncologist.10-8-642 © 2005 AlphaMed Press
Randomized Comparison of Epoetin Alfa (40,000 U Weekly) and Darbepoetin Alfa (200 µg Every 2 Weeks) in Anemic Patients with Cancer Receiving Chemotherapya St. Vincents Comprehensive Cancer Center, New York, New York, USA; b North Mississippi Hematology and Oncology Associates, Tupelo, Mississippi, USA; c Pacific Coast Hematology/Oncology Medical Group, Fountain Valley, California, USA; d Hutchinson Clinic, Hutchinson, Kansas, USA; e Pacific Cancer Medical Center, Anaheim, California, USA; f Ortho Biotech Clinical Affairs, LLC, Bridgewater, New Jersey, USA Correspondence: Roger Waltzman, M.D., Saint Vincents Comprehensive Cancer Center, 325 West 15th Street, New York, New York 10011, USA. Telephone: 212-604-6058; Fax: 212-604-6038; e-mail: rwaltzman{at}aptiumoncology.com
This is the first randomized, open-label, multicenter trial designed and powered to directly compare the hemoglobin (Hb) response to epoetin alfa (EPO), 40,000 U once weekly (QW), with that to darbepoetin alfa (DARB), 200 µ g every 2 weeks (Q2W), in anemic patients with cancer receiving chemotherapy (CT). Transfusion requirements, quality of life (QOL), and safety also were evaluated. Adults with solid tumors scheduled to receive CT for 12 weeks and with baseline Hb 11 g/dl were randomized to receive either EPO 40,000 U QW (n = 178) or DARB 200 µg Q2W (n = 180) s.c. for up to 16 weeks. Doses were increased for nonresponders (Hb increase <1 g/dl) after 4 (EPO) or 6 (DARB) weeks, as per National Comprehensive Cancer Network guidelines, and were reduced for a rapid rise in Hb (>1.3 g/dl [EPO] or >1.0 g/dl [DARB] within any 2-week period) or for an Hb level >13 g/dl. The proportion of patients achieving a 1-g/dl Hb rise by week 5, the primary end point, was significantly higher with EPO (47.0%) than with DARB (32.5%), and EPO-treated patients achieved a 1-g/dl Hb increase significantly earlier than those receiving DARB (median, 35 days versus 46 days). The mean increase in Hb from baseline was significantly higher at weeks 5, 9, 13, and the end of the study with EPO than with DARB. The number of units transfused per patient was significantly lower for the EPO group than for the DARB group. The proportions of patients requiring transfusions, mean QOL improvements, and tolerability profiles were similar in the two groups. Key Words. Epoetin alfa • Darbepoetin alfa • Cancer • Anemia • Transfusions • Randomized trial
Chemotherapy-induced anemia has debilitating effects on patients with cancer [14]. Epoetin alfa (Procrit®; Ortho Biotech Products, L.P., Raritan, NJ, http://www.orthobiotech.com) and darbepoetin alfa (Aranesp®; Amgen Inc., Thousand Oaks, CA, http://www.amgen.com) are growth factors that stimulate RBC formation and are approved and widely adopted for the management of chemotherapy-induced anemia. A large body of clinical evidence exists showing that epoetin alfa, a recombinant human erythropoietin, administered 3 times a week or once weekly (QW), is well tolerated and highly effective at increasing hemoglobin (Hb) and decreasing transfusion requirements in anemic patients with cancer [59]. The successful treatment of anemia with epoetin alfa in this patient population has been shown to correlate with measurable and clinically beneficial increases in energy level, functional status, and quality of life (QOL) [912]. Darbepoetin alfa is a constitutively different erythropoietic protein that is hyperglycosylated, increasing its serum half-life but lowering its binding affinity. Nevertheless, studies suggest that, in patients with cancer receiving chemotherapy, the serum half-lives of epoetin alfa and darbepoetin alfa are similar (40 hours and 3350 hours, respectively) [1316]. Though molecularly distinct from epoetin alfa, darbepoetin alfa binds to the same erythropoietin receptor and stimulates erythropoiesis by the same mechanism [17]. Clinical trials in anemic patients with cancer receiving chemotherapy have demonstrated that darbepoetin alfa also is effective at raising Hb levels and reducing transfusion requirements [1821]. The dosages of epoetin alfa (40,000 U QW) and darbepoetin alfa (200 µg once every 2 weeks [Q2W]) used in this trial have been evaluated in clinical trials [21, 22] and are consistent with those most commonly used in clinical practice and with recommendations from published guidelines [8, 23] regarding the use of these agents. Retrospective studies evaluating the relative efficacy and safety of these two erythropoiesis-stimulating agents have been published [2426]. Unlike previous trials, this prospective trial was specifically designed and powered a priori with a primary end point of statistically comparing the hematologic responses of the two agents.
The primary efficacy end point was the percentage of patients demonstrating an increase in Hb of
The protocol was approved by the investigational review board of the 55 participating U.S. clinical sites, and all patients gave written informed consent.
Study Population Patients were excluded if they had received any erythropoietic agent within 3 months, had anemia due to factors other than cancer or chemotherapy, had received more than two prior chemotherapy regimens, or if radiation therapy was included in their treatment plans. Also excluded were patients with a history of stem cell or bone marrow transplant; untreated brain metastases; uncontrolled hypertension; poorly controlled seizures; known hypersensitivity to mammalian cellderived products or human albumin; transfusion of packed red blood cells (PRBCs) within 28 days; any unstable medical condition; or a history of uncontrolled cardiac arrhythmias, pulmonary embolism, or thrombosis within the previous 6 months.
Study Design Eligible patients were randomized 1:1 to receive either epoetin alfa (starting dose, 40,000 U s.c. QW) or darbepoetin alfa (starting dose, 200 µg s.c. Q2W).
Randomization was stratified by study site and chemotherapy type (platinum- or nonplatinum-based). The study drugs were sponsor-supplied in prepackaged kits for each patient. Epoetin alfa was provided as commercially available Procrit® and darbepoetin alfa was provided as commercially available Aranesp®. The initial study drug administration occurred on day 1 of week 1 and was required to coincide with day 1 of the chemotherapy cycle to minimize early variability in the timing of erythropoietic growth factor administration and response with respect to the chemotherapy cycle [16]. Study treatment was administered for up to 16 weeks. Dose escalation for nonresponders (Hb increase <1 g/dl) occurred based on recommendations of the National Comprehensive Cancer Network [23] and the American Society of Clinical Oncology (ASCO)/American Society of Hematology (ASH) guidelines [8] after 4 weeks (epoetin alfa dose increased to 60,000 U QW) or 6 weeks (darbepoetin alfa dose increased to 300 µg Q2W) of treatment. Study drug was withheld if Hb was >13 g/dl and was resumed at a 25% dose reduction when Hb was An oral supplement of ferrous sulfate, 325 mg, or an equivalent commercially available iron supplement, was to be taken by each patient daily throughout the study, if tolerated and not contraindicated. If not tolerated, an i.v. formulation of iron could have been prescribed. Hb, Hct, and blood pressure were monitored weekly, before administration of study drug. Specifically, with regard to the primary end point, Hb was measured at week 5 before dose escalation. Patients were evaluated monthly (CBC, blood pressure, body weight, transfusion use, changes in chemotherapy, and adverse events [AEs]) for up to 16 weeks on treatment and followed for safety thereafter. Clinical laboratory and ECOG performance status evaluations were done at the study completion. Patients were withdrawn if chemotherapy was discontinued before 12 weeks on therapy or changed from a platinum- to a nonplatinum-based regimen or vice versa. QOL was assessed using the Functional Assessment of Cancer TherapyAnemia Fatigue subscale and the Energy Level and Ability to Perform Daily Activities subscales of the 100-mm Linear Analogue Scale Assessment [28], the results of which have been shown to significantly correlate with Hb level in patients with cancer receiving chemotherapy [29, 30].
End Points
Statistical Analysis The analysis of the primary efficacy end point was based on the first 300 patients to complete 4 weeks of study treatment. The proportions of patients achieving an Hb response by week 5 in the two treatment groups were compared using a logistic regression model with the stratification factor of chemotherapy type. The overall significance level for this analysis was 0.0125, one-sided. The protocol had a provision for an adaptation procedure to increase enrollment to 400 participants should the interim analysis prove inconclusive [32]. Analyses of secondary efficacy end points were based on all patients who received at least one dose of a study drug and had at least one postbaseline Hb value or transfusion (modified intent-to-treat population [mITT]). Hb values obtained within 28 days following a PRBC transfusion were set to missing for all efficacy analyses. Hb data post-transfusion as well as any missing Hb data were analyzed using a last-value-carried-forward (LVCF) method. All secondary efficacy end points were tested at a significance level of 0.05, two-sided.
The time to an Hb increase of 1 g/dl was analyzed by Kaplan-Meier estimates and a Cox regression model with treatment group and chemotherapy type as effects and baseline Hb value as a covariate. The analysis method used for the primary efficacy end point was also performed on the proportion of patients achieving a The changes from baseline in QOL at week 5, week 9, and the end of the study were analyzed by treatment group. A correlation analysis assessed the relationship between changes in Hb and changes in the QOL variables. Patients receiving at least one dose of a study drug were included in the safety analysis. All statistical analyses were done using the SAS statistical software (version 8.2; SAS Institute, Cary, NC, http://www.sas.com).
Study Population Three hundred fifty-eight patients were enrolled and randomized to receive epoetin alfa (n = 178) or darbepoetin alfa (n = 180); of these, 352 (175 epoetin alfa, 177 darbepoetin alfa) were in the mITT population (Fig. 1
Of the 358 randomized patients, 210 (103 [57.9%] epoetin alfa, 107 [59.4%] darbepoetin alfa) completed 12 weeks of chemotherapy on study (Fig. 1 The mean cumulative doses of the study drugs were 418,479.9 U for epoetin alfa patients (n = 178) and 1,178.4 µg for darbepoetin alfa patients (n = 180), and the mean durations of treatment were similar in the two groups (77.0 and 79.5 days, respectively). The percentages of patients who had their dose increased, to 60,000 U QW epoetin alfa at week 5 (33%) or to 300 µg Q2W darbepoetin alfa at week 7 (34%), were similar, as were the percentages of patients in the epoetin alfa and darbepoetin alfa groups who had any dose increase (44% and 41%, respectively) or dose reduction (42% and 31%, respectively).
Efficacy Evaluations
Hb Response by Week 5
The proportions of patients who achieved an Hb increase 1 g/dl or 2 g/dl by week 9 or by the study end were consistently higher with epoetin alfa treatment (Table 2
Overall, for patients included in the primary end point analysis, similar percentages of patients in each treatment group started treatment with iron supplementation (54% in the epoetin alfa group, 49% in the darbepoetin alfa group). Slightly more patients in the darbepoetin alfa group had initial transferrin saturation values 20%.
Time to Hb Response
Change in Hb
Patients who received epoetin alfa had significantly greater mean increases in Hb at all measurement intervals during the study from week 3 to the end of the study (p .023). Mean Hb increases after 4, 8, 12, and 16 (end of study) weeks of treatment were 0.71, 1.02, 1.27, and 1.24 g/dl, respectively, in the epoetin alfa group, compared with 0.28, 0.51, 0.72, and 0.80 g/dl, respectively, in the darbepoetin alfa group. Repeated measures analysis showed that the overall Hb profile was significantly higher in the epoetin alfa group (p = .005).
Transfusion Requirement
QOL Evaluations
Safety Evaluations
Predefined clinically significant thrombotic vascular events were reported for 20 (11%) patients in the epoetin alfa group and 17 (9%) patients in the darbepoetin alfa group (Table 3
With the frequencies of concomitant use of WBC growth factors being similar (although uncontrolled) in the two groups (epoetin alfa, 21.3% [38/178]; darbepoetin alfa, 24.4% [44/180]), similar rates of grades 3 and 4 neutropenia were observed (epoetin alfa, 12% [21/178]; darbepoetin alfa, 17% [31/180]). Fifty-nine patients (epoetin alfa, 25; darbepoetin alfa, 34) had an AE that led to death, all considered to be unrelated to study treatment. Little variation was seen in vital sign measurements or routine physical examination findings in either treatment group. With the exception of larger increases in RBCs and Hb in the epoetin alfa group, there were no differences between the groups in the mean values of the hematology or serum chemistry parameters. No patient in either group tested positive for serum antierythropoietin antibodies.
Results of this prospective, randomized trial in anemic patients with solid tumors receiving chemotherapy demonstrate a hematologic response rate by week 5 that was statistically superior for epoetin alfa (40,000 U s.c. QW) compared with darbepoetin alfa (200 µg s.c. Q2W) and was apparent before dose increases for an inadequate response were allowed in either treatment group. In addition, patients treated with QW epoetin alfa had significantly greater increases in weekly Hb from week 3 to the study end. The Hb responses for epoetin alfa at week 5 and at the study end were similar to results previously observed for epoetin alfa 40,000 U QW (47%66%; [9], data on file). Weekly Hb results have not been previously reported for darbepoetin alfa 200 µg Q2W, so this study provides the first published account of the weekly Hb performance for this regimen throughout the duration of treatment. There did not appear to be convincing evidence that baseline iron status or iron supplementation was a confounding variable in results for the primary end point of response rate in this study. Analyses of previous data showed that an early Hb response was associated with significantly better clinical outcomes [27]. Separate exploratory analyses for this study were done [33] and confirmed that early Hb response is an appropriate measure to evaluate treatment effects. Also, because the average treatment duration for erythropoietic therapies has been shown to be approximately 810 weeks [34, 35], an earlier response to treatment is desirable. Most previously published comparisons of epoetin alfa and darbepoetin alfa have been retrospective pooled analyses of previously conducted studies [2426]. Such investigations introduce the potential for confounding biases because of differences in study design, patient populations, and statistical methodologies, and also for reporting bias, because they are not designed nor powered to make statistical comparisons. Recently, Schwartzberg and colleagues reported the results of a pooled analysis of three randomized prospective trials comparing epoetin alfa (40,000 U QW) with darbepoetin alfa (200 µg Q2W) in patients with chemotherapy-induced anemia [36]. The trials were designed to validate a specific QOL tool. The authors conclusion that the two agents achieved comparable hematologic outcomes was based on selected secondary study assessments. Conversely, the present study was designed and powered as a superiority trial to directly compare the hematologic responses of epoetin alfa and darbepoetin alfa. Although there was a significant difference in favor of epoetin alfa for mean units transfused per transfused patient (transfusion intensity) in this study, the overall percentage of patients who required at least one PRBC transfusion between week 5 and the study end (transfusion frequency) and the corresponding monthly transfusion rate were only numerically lower for epoetin alfa than for darbepoetin alfa (no statistical significance). QW epoetin alfa and Q2W darbepoetin alfa provided similar improvements in QOL, perhaps because both treatments were active in raising Hb levels. Both agents also demonstrated similar safety profiles.
Epoetin alfa and darbepoetin alfa are widely prescribed for the management of chemotherapy-induced anemia. This adequately powered, randomized comparison of response rates of weekly s.c. administration of epoetin alfa (40,000 U) and darbepoetin alfa (200 µg) given Q2W in patients with chemotherapy-induced anemia demonstrated an earlier hematologic response for epoetin alfa. Transfusion intensity, but not transfusion frequency, also was significantly lower for epoetin alfa.
Investigator list. Alabama: Susan M. Ferguson, M.D., Allen L. Yeilding, M.D., Birmingham; Luis F. Pineda, M.D., Hoover. Arkansas: Carroll Scroggin, Jr., M.D., Jonesboro. California: Veena Charu, M.D., Anaheim; Haresh S. Jhangiani, M.D., Glen R. Justice, M.D., Fountain Valley; Peter Eisenberg, M.D., Greenbrae; N. Simon Tchekmedyian, M.D., Long Beach; Syed Jilani, M.D., Redondo Beach; Prasad R. Dighe, M.D., Stockton; Peter P. Yu, M.D., Sunnyvale. Colorado: Mark Hancock, M.D., Michael McLaughlin, M.D., Denver. Delaware: Michael J. Guarino, M.D., Newark. Florida: Craig W. Englund, M.D., Inverness; Yousif Abubakr, M.D., Jacksonville; Michael J. Kelley, M.D., Ph.D., Ormond Beach; Ranjith B. Dissanayake, M.D., Allen Patton, M.D., Pensacola. Georgia: Frederick M. Schnell, M.D., F.A.C.P., Macon. Hawaii: Brian Issell, M.D., Honolulu. Illinois: Joyce Samuel, M.D., Chicago. Kansas: Mark R. Fesen, M.D., Hutchinson. Kentucky: John T. Hamm, M.D., Louisville. Louisiana: Harry McGaw, M.D., Houma. Maryland: Young Joo Lee, M.D., Stephen Noga, M.D., David Andrew Riseberg, M.D., Baltimore. Massachusetts: Reed Drews, M.D., Boston. Mississippi: Christopher C. Croot, M.D., Tupelo. Missouri: Patrick L. Gomez, M.D., Springfield. New Jersey: Michael A. Schleider, M.D., Englewood; Stanley Waintraub, M.D., Hackensack. New Mexico: Timothy M. Lopez, M.D., Santa Fe. New York: Barry H. Kaplan, M.D., Ph.D., Fresh Meadows; James T. DOlimpio, M.D., Manhasset; Paolo A. Paciucci, M.D., New York City; Seetha R. Murukutla, M.D., Staten Island. North Carolina: Jennifer L. Garst, M.D., Durham; Glenn Lesser, M.D., Winston-Salem. North Dakota: Louis Geeraerts, M.D., Fargo. Ohio: Leslie R. Laufman, M.D., Columbus. Oklahoma: Howard Ozer, M.D., Oklahoma City. Oregon: Mark U. Rarick, M.D., Portland. South Carolina: George Geils, Jr., M.D., Charleston. Texas: David H. Gordon, M.D., Garry H. Schwartz, M.D., San Antonio. Virginia: Forrest Swan, Jr., M.D., Abingdon; Attique Samdani, M.D., Richmond; Paul D. Richards, M.D., Salem; Masoom Kandahari, M.D., Woodbridge. Washington: David E. McCune, M.D., Tacoma; Rakesh Gaur, M.D., Vancouver. Wisconsin: Tarit K. Banerjee, M.D., Marshfield.
Dr. Waltzman is a consultant for, owns stock in, and receives support from Ortho Biotech/Johnson & Johnson. Dr. Charu owns stock in Pacific Cancer Medical Center. Dr. Williams owns stock in Johnson & Johnson and is an employee of Ortho Biotech Clinical Affairs, LLC.
Results of this study were presented at the 2005 ASCO Annual Meeting (abstract 8030), the 2004 ASCO Annual Meeting (abstract 8153), the 2004 ASH Annual Meeting (abstract 4233), and the 2003 ASH Annual Meeting (abstract 4391).
We wish to acknowledge Patricia Matone of Scientific Information Services for writing contributions and PPD Development for site monitoring, data management, statistics, and programming. This is study PR02-27-047, sponsored by Ortho Biotech Clinical Affairs, L.L.C.
Henry DH. Epoetin alfa for the treatment of cancer- and chemotherapy-related anaemia: product review and update. Expert Opin Pharmacother 2005;6:295310.[Medline] Witzig TE, Silberstein PT, Loprinzi CL et al. Phase III, randomized, double-blind study of epoetin alfa compared with placebo in anemic patients receiving chemotherapy. J Clin Oncol 2005;23:26062617. This article has been cited by other articles:
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