Objective: Erythropoiesis stimulating agent (ESA) resource utilisation in cancer chemotherapy patients is of importance to managed-care organisations. To understand current real-world utilisation of ESAs, this study examined epoetin alfa (EPO) and darbepoetin alfa (DARB) treatment patterns (dosing and treatment duration), dose ratio and ESA treatment costs.
Methods: An analysis of medical claims data from January 2006 through to January 2008 was conducted using the PharMetrics Patient-Centric database of over 85 health plans. Patients included in the study were > or =18 years of age, had at least one cancer claim within 90 days prior to ESA treatment initiation, were newly initiated on EPO or DARB, received at least two doses, and were treated with concomitant chemotherapy (at least one chemotherapy claim during ESA treatment). Mean cumulative ESA dose was used to calculate drug cost (based on April 2008 wholesale acquisition cost) and dose ratio (units EPO : microg DARB).
Results: A total of 4,111 EPO patients and 6,817 DARB patients met inclusion criteria and formed the study population. EPO-treated patients were slightly older (mean age: EPO 63.6, DARB 61.8, p<0.0001) with a greater proportion of women in the DARB-treated group (EPO 60.9%, DARB 64.1%, p=0.0007). The mean treatment duration was slightly longer in the EPO group (EPO 58.4 days, DARB 55.4 days, p=0.0019). The mean cumulative ESA dose administered was EPO 329,129 units and DARB 1,289 microg, resulting in a dose ratio of 255:1 (units EPO:microg DARB). Mean drug cost per treatment episode was significantly lower in the EPO group by $1,768 (EPO $4,321, DARB $6,089, p<0.0001). After controlling for covariates, the incremental cost associated with DARB treatment remained stable and statistically significant (adjusted cost difference: $1,806 per treatment episode higher for DARB patients than EPO, p<0.0001).
Conclusions: This study of 10,928 oncology patients receiving chemotherapy reported a dose ratio of 255:1 (units EPO:microg DARB) with 29% lower treatment cost in the EPO group. These findings are similar to those previously reported from published clinical trials and real-world utilisation studies.