Abstract
Background
In 2005, the mean weekly dose ratio of epoetin alfa (EA) to darbepoetin alfa (DA)
in clinical practice was estimated to be ∼400 to 1. In 2006, a 500-μg dose and new
dosing schedule was approved for DA in the United States. In 2007, the warnings and
dosing/administration sections were modified for both agents. All of these factors
may have changed the way that physicians use EA and DA. Previous studies of the use
of erythropoiesis-stimulating agents (ESAs) in patients with anemia concomitant with
chemotherapy may thus not reflect current clinical practice.
Objective
The goal of this study was to examine the use and costs of ESAs in clinical practice
in patients with anemia concomitant with chemotherapy.
Methods
Using 2 large US health care claims databases, all adults (aged ≥18 years) were identified
who received ESAs in 2008 and had evidence of receipt of chemotherapy ≤42 days before
initial ESA receipt (ie, the index date). Episodes of care were defined as beginning
on the index date and ending on the date of the last ESA claim that was followed by
a ≥42-day gap without any receipt of ESAs, to which was added an assumed duration
of clinical benefit (in days) based on the ESA and corresponding dose received. DA-
and EA-treated patients were matched using propensity scoring. The mean weekly dose
and cost of DA and EA during episodes of care was calculated using all information
from relevant claims noted during such episodes. Each database was analyzed separately.
Results
In the first database, 475 patients with DA episodes of care were matched to an equal
number of patients with EA episodes; in the second database, there were 424 matched
pairs. In the first database, the mean (95% CI) weekly dose was 37,444 U (35,942 U–39,001
U) during EA episodes and 110 μg (108 μg–113 μg) during DA episodes; the mean weekly
EA/DA dose ratio was 340 to 1. In the second database, the mean (95% CI) weekly dose
was 37,047 U (35,944 U–38,175 U) during EA episodes and 121 μg (117 μg–125 μg) during
DA episodes; the mean weekly EA/DA dose ratio was 306 to 1.
Conclusions
The mean weekly EA/DA dose ratio during episodes of ESA care has declined in patients
with anemia concomitant with chemotherapy, due at least in part to the availability
and use of a new dose/dosing schedule for DA without similar changes for EA.
Key words
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Article info
Publication history
Published online: May 17, 2012
Accepted:
April 20,
2012
Identification
Copyright
© 2012 Elsevier HS Journals, Inc. Published by Elsevier Inc. All rights reserved.
