Abstract

Objective: To assess the treatment patterns and hematologic outcomes associated with epoetin alfa (EPO) and darbepoetin alfa (DARB) for the treatment of anemic cancer patients in the community practice setting.

Methods: A retrospective observational study design was used. De-identified data from patients receiving care in community oncology practice settings were obtained from an electronic medical record system. Eligible patients were >= 18 years of age, had a cancer diagnosis, and were treated with an erythropoiesis stimulating agent (ESA: EPO or DARB) during the period July 2002 – July 2004, with baseline anemia (Hb<=11 g/dL) and at least one follow-up Hb value. No other selection criteria were applied (e.g. ESA dose, tumor type, chemotherapy treatment) in keeping with the objective of characterizing outcomes in a real-world setting. Data were summarized by treatment overall and by using a multivariate model adjusting for age, gender, baseline Hb, clinic site, ECOG performance score, type of cancer (solid vs hematologic) and chemotherapy (platinum vs non-platinum vs. none). Patient selection criteria and analytic methods were determined prospectively. The cost for each ESA was calculated based on 2004 average wholesale prices ($13.36 per EPO 1,000 U; $4.99 per 1 mcg DARB).

Results: 2382 EPO and 1399 DARB patients were eligible for analysis. The two groups were comparable in terms of baseline characteristics (62% female, 75% solid tumors, mean baseline Hb 9.9 g/dL). Only about two-thirds of patients were treated with standard dosing regimens of the two agents in the US (EPO 40,000 U qw, DARB 200 mcg q2w). Hematologic outcomes observed in patients receiving EPO were consistently better than those in patients receiving DARB.

Table 1.

Hematologic outcomes by ESA treatment

EPODARBp value
Week 4 Hb change (g/dL) 0.79 0.59 <0.001 
% Early Hb response (Hb change >=1 g/dL at 4 weeks) 61.5 55.2 0.004 
% Hb response (Hb change >=2 g/dL by end of treatment episode) 41.4 34.7 <0.001 
% Hematopoietic response (Hb change >= 2 g/dL or reaching 12 g/dL by end of treatment episode) 52.3 44.6 <0.001 
EPODARBp value
Week 4 Hb change (g/dL) 0.79 0.59 <0.001 
% Early Hb response (Hb change >=1 g/dL at 4 weeks) 61.5 55.2 0.004 
% Hb response (Hb change >=2 g/dL by end of treatment episode) 41.4 34.7 <0.001 
% Hematopoietic response (Hb change >= 2 g/dL or reaching 12 g/dL by end of treatment episode) 52.3 44.6 <0.001 

The mean treatment durations for patients receiving EPO and DARB were 55.3 and 62.5 days, respectively. Mean cumulative doses were 231,211 U for EPO and 857 mcg for DARB. These doses resulted in an average cost per patient of $3,089 for those receiving EPO and $4,276 for those receiving DARB.

Conclusion: These results, based on over 3000 community-treated cancer patients, reinforce previous findings of earlier and greater overall hematologic response for EPO vs. DARB in this setting. Additionally, based on mean cumulative doses, the cost of DARB per patient was substantially greater than that of EPO. Additional studies of variations in dosing regimens used in the community setting are warranted, as are well-powered, randomized, controlled trials to further confirm the clinical results observed here.

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