A Randomized Comparison of Standard Weekly Epoetin Alfa to Every-3-Week Epoetin Alfa and Every-3-Week Darbepoetin Alfa: A Study of the Mayo Clinic Cancer Research Consortium (MCCRC).

Abstract

Abstract 3008Poster Board II-984 Introduction:The erythropoiesis-stimulating agents (ESAs) epoetin alfa (EA) and darbepoetin alfa (DA) increase hemoglobin (Hb) levels and reduce red blood cell (RBC) transfusion requirements in patients (pts) with cancer chemotherapy-associated anemia (CAA). Extended-interval ESA dosing (i.e., administration less than once weekly) is a common practice with DA, which is FDA approved for dosing once every 3 weeks (q3wks); a previous study of the North Central Cancer Treatment Group suggested that EA can also be given less often than the FDA-approved once weekly schedule (Steensma DP et al, J Clin Onc 2006; 24:1079). The present study compared 2 different q3wks extended-interval EA regimens with weekly fixed-dose EA and with q3wks DA in pts with CAA. Patients and Methods:Eligible pts were receiving chemotherapy for a non-myeloid malignancy and had Hb <10.5 g/dL, ferritin >20 ng/mL, weight >40 kg and <150 kg, and ECOG performance score £2. Pts were randomized 1:1:1:1 to receive EA 40,000 Units subcutaneously (SC) once weekly (40K arm), EA 80,000 Units SC q3wks (80K arm), EA 120,000 Units SC q3wks (120K arm), or DA 500 mcg SC q3wks (DA arm), for 15 weeks. EA and DA were held for Hb >12 g/dL and restarted at a lower dose when Hb fell to '11.5 g/dL. All pts received ferrous sulfate 325 mg orally once daily, if tolerated. Quality of life (QOL) was measured using the Symptom Distress Scale (SDS), Brief Fatigue Inventory (BFI), FACT-An, and Linear Analogue Self Assessment (LASA) tools. The primary endpoint was the proportion of pts achieving Hb≥11.5 g/dL or increment of Hb>2.0 g/dL from baseline. Secondary endpoints included RBC transfusion requirements, adverse events (AEs), and QOL. Results:239 pts (236 evaluable) enrolled at 10 MCCRC sites between Feb. 2007 and Dec. 2008; 62% of pts completed all study interventions. The median age of enrolled pts was 66 years; 42.4% were men, 91.5% had solid tumors, 26.7% had severe anemia (Hb <9.5 g/dL), and 44.9% were receiving platinum-containing regimens. Baseline characteristics were balanced between study arms, with the exception of gender (39% female for 40K, 60% for 80K, 43% for 120K, 26% for DA). There were no significant differences between treatment arms in the proportion of pts achieving a Hb response (68.9% for 40K, 61.7% for 80K, 65.5% for 120K, and 66.7% for DA; p>0.41 for all comparisons), but the median Hb increment from baseline was higher in the 40K and DA arms compared to the 2 extended dosing EA arms (40K-2.8 g/dL, 80K-2.0 g/dL, 120K-2.1 g/dL, DA-2.6 g/dL; p=0.005 for 40K vs 80K). Hb response was achieved more quickly in the weekly EA arm, but the difference was not significant (40K-32 days, 80K-50 days, 120K-49 days, DA-49 days; p>0.13). The proportion of patients transfused was similar between arms (40K-27.9%, 80K-33.3%, 120K-22.4%, DA-29.8%; p>0.49). There were no significant differences in QOL changes. Deaths were also similar between arms (40K-5 pts, 80K-7 pts, 120K-7 pts, DA-1 pt, p>0.10) and were primarily due to disease progression. AEs and serious AEs were comparable between study groups; grade 3/4 AEs were observed in 22% of pts in the 40K arm, 22% on 80K, 17% on 120K, and 13% on DA; p>0.56. The median total dose of EA used was highest in the 120K arm (40K-265,000 U; 80K-240,000 U; 120K-360,000 U; p=0.0009 for 40K vs 120K), while pts on the 40K arm were more likely to omit a dose due to a high Hb (40K-63.9% of pts omitted at least one dose; 80K-30.0%; 120K-34.5%; DA-43.6%, p<0.0001 for 40K vs 80K). Conclusion:Although there was no significant difference in the proportion of responding pts (the primary endpoint), Hb increments from baseline were moderately higher with the 2 FDA-approved regimens – weekly EA 40,000 Units, and q3wk DA 500 mcg – than with the extended dosing regimens.This study was supported by a grant from Centocor Ortho Biotech, Inc. to the MCCRC. Disclosures:No relevant conflicts of interest to declare.