(076) Evaluating the Incidence of Febrile Neutropenia Associated with Pegfilgrastim and Filgrastim Use in Patients Greater than 65 Years Old Receiving RCHOP Regimen

Poster Abstract:

Background: In patients receiving chemotherapy, febrile neutropenia (FN) is associated with increased mortality, prolonged hospitalizations, and treatment delays. According to the National Comprehensive Cancer Network (NCCN) guidelines, R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) is categorized as having an intermediate risk for FN. Upfront GCSF is recommended for who meet any of the following criteria: history of prior chemotherapy/radiation therapy, persistent neutropenia, bone marrow involvement by the tumor, recent surgery and/or open wounds, liver/renal dysfunction, or patients aged 65 years or older. There is minimal evidence to support a preferred GCSF product in patients aged 65 years or older. Based on anecdotal evidence, providers believe that pegfilgrastim may exhibit different pharmacokinetics than filgrastim in elderly patients and be less effective in preventing FN.

Objectives: The primary objective was to evaluate admissions for FN in patients aged 65 years or older who received RCHOP chemotherapy with GCSF support. Secondary objectives included frequency of grade 4 neutropenia, rate of hospitalizations, occurrence of chemotherapy delays, and prevalence of infections.

Methods: This study was a retrospective analysis at an academic medical center between January 2020 and 2023. Eligible participants were 65 years or older who commenced R-CHOP treatment and had received GCSF support for a minimum of 3 out of the 6 planned R-CHOP cycles.

Results: Fifty-nine patients underwent 338 cycles of R-CHOP. Patients received filgrastim for a total of 17 cycles and pegfilgrastim for 289 cycles, while GCSF support was not utilized in 32 cycles. The total incidence of FN occurred in 9 cycles (2.7%) with 11.8% associated with receiving filgrastim and 2.4% receiving pegfilgrastim. Grade 4 neutropenia occurred in 29.4% vs. 10% cases. Hospitalization rates occurred in 11.8% vs. 2.4% instances. Meanwhile, delayed chemotherapy occurred in 1 patient receiving filgrastim and 2 patients receiving pegfilgrastim. Twenty-six infections were reported in 23.5% vs. 6.2% cases. Infections were most frequently reported in Cycle 1 (15.3%).

Conclusions: FN varied across cycles and GCSF types, occurring mostly in Cycle 1. Incidence of FN was low among patients receiving pegfilgrastim. While filgrastim was less commonly administered, it was also associated with low incidences of FN. Results emphasize the importance of GCSF use in this patient population. Limitations of the study include that most patients received pegfilgrastim (>85%) resulting in a barrier to assess outcomes between agents. Future comparator studies are needed to assess the incidence of FN in this patient population to determine their efficacy.

References (must also be included in final poster): 1. Morrison VA, Picozzi V, Scott S, Pohlman B, Dickman E, Lee M, Carter WB. The impact of age on delivered dose intensity and hospitalizations for febrile neutropenia in patients with intermediate- grade non-Hodgkin’s lymphoma receiving initial CHOP chemotherapy. Clinical Lymphoma. 2001; 2:47–56. [PubMed: 11707870]
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3. Chrischilles E, Delgado DJ, Stolshek BS, Lawless G, Fridman M, Carter WB. Impact of age and colony-stimulating factor use on hospital length of stay for febrile neutropenia in CHOP-treated non-Hodgkin’s lymphoma. Cancer Control. 2002; 9:203–211. [PubMed: 12060818]
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