Darbepoetin alfa for treating chemotherapy-induced anemia in patients with a baseline hemoglobin level < 10 g/dL versus ≥10 g/dL: an exploratory analysis from a randomized, double-blind, active-controlled trial
1 Respiratory Oncology Unit (Pulmonology), University Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
2 Department of Medicine, Sundsvall Hospital, Sundsvall, Sweden
3 Department of Medical Oncology at the Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain
4 Department of Oncology (Hematology with Section Pneumology), University Hospital Hamburg Eppendorf, Hamburg, Germany
5 1st Department of Medicine at the Center for Oncology and Haematology, Wilhelminenspital der Stadt Wien, Vienna, Austria
6 Department of Medical Oncology, University Hospital Antwerp, Edegem, Belgium
7 Biostatisics and Epidemiology, Amgen Ltd, Cambridge, UK
8 Hematology/Oncology Therapeutic Area, Amgen Inc., Thousand Oaks, CA, USA
9 Hematology/Oncology Therapeutic Area, Amgen Europe, Zug, Switzerland
BMC Cancer 2009, 9:311 doi:10.1186/1471-2407-9-311Published: 3 September 2009
Several studies have shown that darbepoetin alfa, an erythropoiesis-stimulating agent (ESA), can reduce transfusions and increase hemoglobin (Hb) levels in patients with chemotherapy-induced anemia (CIA). Recent safety concerns, however, have prompted changes to ESA product information. In the European Union and United States, ESA therapy initiation for CIA is now recommended at a Hb level ≤10 g/dL. The present exploratory analysis examined how ESA initiation at this Hb level may impact patient care.
Data from a phase 3 randomized trial were retrospectively reanalyzed. CIA patients with nonmyeloid malignancies were randomized 1:1 to 500 mcg darbepoetin alfa every three weeks (Q3W) or 2.25 mcg/kg darbepoetin alfa weekly (QW) for 15 weeks. A previously published report from this trial showed Q3W dosing was non-inferior to QW dosing for reducing transfusions from week 5 to end-of-the-treatment period (EOTP). In the present analysis, outcomes were reanalyzed by baseline Hb <10 g/dL and ≥10 g/dL. Endpoints included transfusion rates, Hb outcomes, and safety profiles.
This study reanalyzed 351 and 354 patients who initiated ESA therapy at a baseline Hb of <10 g/dL or ≥10 g/dL, respectively. From week 5 to EOTP, the estimated Kaplan-Meier transfusion incidence (Q3W vs QW) was lower in the ≥10 g/dL baseline-Hb group (14% vs 21%) compared with the <10 g/dL baseline-Hb group (36% vs 41%). By week 5, the ≥10 g/dL baseline-Hb group, but not the <10 g/dL baseline-Hb group, achieved a mean Hb ≥11 g/dL. The Kaplan-Meier estimate of percentage of patients (Q3W vs QW) who achieved Hb ≥11 g/dL from week 1 to EOTP was 90% vs 85% in the ≥10 g/dL baseline-Hb group and 54% vs 57% in the <10 g/dL baseline-Hb group. Both baseline-Hb groups maintained mean Hb levels <12 g/dL and had similar safety profiles, though more patients in the ≥10 g/dL baseline-Hb group reached the threshold Hb of ≥13 g/dL.
In this exploratory analysis, darbepoetin alfa Q3W and QW raised Hb levels and maintained mean Hb at <12 g/dL in both baseline-Hb groups. The ≥10 g/dL baseline-Hb group had fewer transfusions and faster anemia correction. Additional studies should prospectively evaluate the relationship between Hb levels at ESA initiation and outcomes.
ClinicalTrials.gov Identifier NCT00118638.