Abstract PS9-50: A multicenter, prospective, observational study to determine the incidence of febrile neutropenia (FN), persistence and G-CSF utilization among cancer patients at high risk for FN receiving pegfilgrastim by an on-body injector (OBI) versus other FN prophylaxis strategies: An interim analysis
Authors: Mahtani Reshma L. , Crawford Jeffrey , Rifkin Robert , Dale David , Brookhart Alan , Gawade Prasad L. , Lewis Sandra , Lawrence Tatiana , Belani Rajesh , Lyman Gary H. 
Published: February 2021

Background Pegfilgrastim is a long-acting granulocyte colony-stimulating factor (G-CSF) shown to effectively reduce the risk of chemotherapy-induced FN. Pegfilgrastim should be administered on the day after chemotherapy completion (Lyman, Cancer, 2017). For patient convenience, an OBI was developed to deliver pegfilgrastim 27 hours after OBI application on the day of chemotherapy. Real-world data on whether OBI improves patient persistence, compliance, and outcomes are limited. To address this, a multicenter, prospective, observational study was conducted to describe the incidence of FN, persistence, and G-CSF utilization among patients treated with myelosuppressive chemotherapy for non-myeloid malignancies who received pegfilgrastim by OBI or other physician choice options for FN prophylaxis. Here, we report the interim results of the study. Methods Adult patients with breast, prostate, lung cancer, or non-Hodgkin’s lymphoma were stratified into 2 groups, curative or palliative intent, and classified into subgroups of FN prophylaxis based on the first chemotherapy cycle: receiving pegfilgrastim OBI (OBI group) vs other options (Other group; options: pegfilgrastim or biosimilar pegfilgrastim prefilled syringe [PFS], daily filgrastim, no G-CSF) up to 4 planned chemotherapy cycles. Additional eligibility criteria included a life expectancy of &gt;6 months, chemotherapy with high (&gt;20%) FN risk or intermediate (10%-20%) FN risk with ≥1 risk factor administered once every 3 or 4 weeks, and no radiation &lt;2 weeks before enrollment. The prespecified analysis was based on the first 2,000 enrolled patients who completed up to 4 chemotherapy cycles. The primary endpoint is the incidence of FN (defined as absolute neutrophil count [ANC] &lt;1,000 × 106/L and one of the following occurring within 24 hours of decreased ANC: temperature &gt;38°C, use of intravenous antibiotics, or use of oral antibiotics). The clinical study team was blinded to FN per group at the time of analysis. Secondary endpoints include persistence (defined as G-CSF support for all chemotherapy cycles regardless of the timing of administration). G-CSF utilization was included as an exploratory endpoint. Results For the analysis, 1,930 patients were eligible (OBI, 1208; Other, 722). Patients were characterized in table 1 regarding sex, age, tumor type, and FN risk of chemotherapy regimens administered. Most patients were female (OBI, 82.0%; Other, 71.7%). The most common tumor type was breast (OBI, 72.4%; Other, 57.5%). The proportion of patients undergoing chemotherapy regimens with high FN risk was higher in the OBI group than in the Other group. The overall incidence of FN was 7.3% (95% confidence interval [CI], 6.1%-8.4%). In the Other group, 60.5% of patients received pegfilgrastim PFS, 7.6% received a short-acting G-CSF, and 30.6% did not receive G-CSF support in the first cycle. Persistence to G-CSF support was 93.5% (95% CI, 92.2%-94.9%) for the OBI group and 56.9% (53.3%-60.5%) for the Other group. Updated data will be presented at the meeting. Conclusions The OBI improved adherence to clinically appropriate G-CSF support across all chemotherapy cycles. However, approximately a third of patients did not receive primary prophylaxis with G-CSF despite being considered as a high risk for FN.

CharacteristicOn-Body Injector (N=1,208)Other Physician Choice Options (N=722)Sex, n (%)Male218 (18.0)204 (28.3)Female990 (82.0)518 (71.7)Age&lt;65 years, n (%)679 (56.2)397 (55.0)Median, years63.062.0Tumor type,a n (%)Breast874 (72.4)415 (57.5)Non-Hodgkin’s lymphoma178 (14.7)142 (19.7)Lung107 (8.9)104 (14.4)Prostate49 (4.1)51 (7.1)FN risk of chemotherapy, n (%)High777 (64.3)330 (45.7)Intermediate376 (31.1)326 (45.2)Unknown55 (4.6)66 (9.1)aTen patients were missing a tumor type in the Other Physician Choice Options group. FN, febrile neutropenia

Citation Format: Reshma L. Mahtani, Jeffrey Crawford, Robert Rifkin, David Dale, Alan Brookhart, Prasad L. Gawade, Sandra Lewis, Tatiana Lawrence, Rajesh Belani, Gary H. Lyman. A multicenter, prospective, observational study to determine the incidence of febrile neutropenia (FN), persistence and G-CSF utilization among cancer patients at high risk for FN receiving pegfilgrastim by an on-body injector (OBI) versus other FN prophylaxis strategies: An interim analysis [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-50.