PD06-05: Primary and Secondary Pegfilgrastim Utilization in Adjuvant Chemotherapy for Breast Cancer in the Community.
Authors: Patt DA , Espirito JL , Turnwald B , Hoverman JR , Neubauer MA , Busby LT , Brooks BD , Kolodziej MA , Anderson RW , Beveridge RA ,   On Behalf of US Oncology Pathways Task Force and Clinical Content Development Team
Published: June 2012

Abstract
Background
Various factors are taken into consideration in the selection of adjuvant breast cancer (BC) chemotherapy (CT) regimens for patients. Choice of CT, schedule, duration, and supportive care affects costs and toxicity. Understanding clinical practice utilization patterns are important when making cost estimates of adjuvant therapy. Because pegfilgrastim is a large driver of cost it is important to understand the utilization characteristics. We aimed to characterize primary and secondary pegfilgrastim use during neoadjuvant/adjuvant (N/Ad) chemotherapy by regimen type. While initial data suggests the incidence of febrile neutropenia (FN) is low among some docetaxel containing regimens, we wanted to further characterize pegfilgrastim utilization, as previous utilization studies suggested it was higher than expected.
Methods: Using the US Oncology iKnowMed™ EHR database, we retrospectively identified female BC patients (pts) diagnosed with stage I-III BC, between 7/2006 and 11/2010. Secondary diagnoses were excluded. Pts were characterized by age, ER and HER2 status, tumor size, grade, and nodes. CT utilization was determined by the number of pts assigned an N/Ad line of therapy (LOT) during the study period. Regimens were categorized by CT title and drugs. Clinical trial pts were included. Pegfilgrastim utilization was characterized if administered within 6 months of being assigned to an N/Ad CT regimen, and was captured as primary prophylaxis if the first dose was administered &lt;5 days of C1D1 of a regimen, and secondary prophylaxis if &gt;5days.
Results: General chemotherapy and pegfilgrastim utilization characteristics were previously reported. This report captures primary vs. secondary pegfilgrastim use. During the time period, 40,881 BC pts were identified. Of these, 15,328 pts (37%) were assigned an N/Ad CT regimen and 72% (11, 022 pts) received pegfilgrastim at any time within 6 months of their N/Ad regimen. Docetaxel containing regimens (TC, TAC, TCH) and dose-dense regimens accounted for the majority of all pegfilgrastim use. Pegfilgrastim utilization with the TC regimen was 70%, and represented 25% of all N/Ad pegfilgrastim utilization. The vast majority of utilization for TC and TCH was primary prophylaxis as detailed below:

Conclusions: While primary prophylaxis in regimens like dose-dense AC and TAC are expected, the primary utilization of pegfilgrastim in TC and TCH is higher than expected based on published clinical trial experience. The incidence of FN has been reported at 5% in the clinical trial by Jones et al with TC, however subsequent reports suggest the incidence of FN may be higher than expected. Our results demonstrate high primary prophylaxis utilization adoption in clinical practice. With the availability of generic docetaxel, commonly used drugs in adjuvant BC except trastuzumab have generic equivalents. Pegfilgrastim will be the largest cost driver in women receiving adjuvant chemotherapy and should be considered among cost estimates. This study may underestimate utilization of pegfilgrastim if it was administered outside of the cancer center.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-05.