8115 Background: The frequency of neutropenia-related complications during chemotherapy (CT) is reduced by the use of pegfilgrastim (Neulasta) and filgrastim (Neupogen). The introduction of pegfilgrastim in 2002 may have changed both the use of filgrastim and the outcomes related to neutropenia. Methods: 99 US community oncology practices, stratified by CT use, participated in the study. Consecutive medical records were abstracted for adult cancer patients (pts) receiving CT in 2001 with filgrastim support (pre-pegfilgrastim launch) or in 2003 with pegfilgrastim support (post-pegfilgrastim launch). The associated CT was initiated from Jan 1 to Dec 31 in 2001 or 2003. In addition to clinical records documenting the complications of CT (febrile neutropenia and hospitalization) available in pt charts, additional data was derived from available laboratory results. Results: 2751 charts documented pegfilgrastim or filgrastim use; 829 pts received filgrastim in 2001; 1922 pts received pegfilgrastim in 2003. The 3 most common tumor types observed were breast cancer (51%), lung cancer (19%), and NHL (18%). The predominant CT cycle length was Q21 days. A total of 39% (95% CL: 36, 41) of pts receiving pegfilgrastim were reported to have neutropenia (ANC < 1 x 109/L) compared with 51% (95% CI: 48, 55) of filgrastim pts. CT-related outcomes that are associated with neutropenia are in the table below. Conclusions: Neutropenia-related complications of CT were observed to be lower in pts receiving pegfilgrastim in 2003 (1 year post pegfilgrastim launch) compared with pts receiving filgrastim in 2001 (1 year before pegfilgrastim launch). Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen Amgen Amgen