Use of Chemotherapy and Same-Day Pegfilgrastim Prophylaxis in US Clinical Practice
Authors: Weycker Derek , Wu Hongsheng , Hagiwara May , Li Xiaoyan , Barron Richard L 
Published: October 2019

Abstract
Background: Primary prophylaxis with pegfilgrastim has been shown to reduce the risk of febrile neutropenia, a life-threatening consequence of myelosuppressive chemotherapy. Pegfilgrastim is not indicated for administration during the interval between 14 days before and 24 hours after cytotoxic chemotherapy because pegfilgrastim induces proliferation of myeloid progenitor cells, and these proliferating cells may be especially sensitive to myelotoxic agents. A randomized, double-blind, phase 2 study (Burris 2010) and observational studies (Skarlos 2009, Cheng 2014) have reported poorer outcomes with same-day pegfilgrastim administration compared to next-day administration. Nonetheless, some healthcare providers administer pegfilgrastim to their patients on the same day as chemotherapy rather than requiring the patients to return for an injection the next day. This is the first large-scale analysis of same-day pegfilgrastim use in US clinical practice.
Methods: In this retrospective cohort study, we examined the day of administration of pegfilgrastim prophylaxis relative to the completion of chemotherapy in adults with solid tumors (eg, breast cancer, colorectal cancer, and lung cancer) and non-Hodgkin’s lymphoma (NHL) treated in the outpatient setting. Data spanning 2003–2011 were obtained from 2 large private US healthcare claims databases—the Truven Health Analytics MarketScan® Database and the IMS Health PharMetrics Plus™ Database—and were pooled for analysis. Only patients who received triweekly (Q3W) or monthly (Q4W) chemotherapy regimens were included. For each patient, only the first documented chemotherapy course was included, and in the first course, only cycles with medical claims for pegfilgrastim prophylaxis were included. Administration of pegfilgrastim prophylaxis was classified as day 0 (same day), day 1, days 2-3, or days 4-5 relative to the last day of administration of myelosuppressive chemotherapy in the cycle. Analyses were conducted on an overall basis as well as by tumor type and chemotherapy regimen.
Results: We identified 69,509 patients who received pegfilgrastim prophylaxis in 244,687 chemotherapy cycles. We found that pegfilgrastim was administered on the same day as chemotherapy in 13.4% of first cycles and 13.0% of subsequent cycles. Table 1 shows patient characteristics for 4 of the most common tumor types. Table 2 shows the day of pegfilgrastim administration.
Conclusion: This large retrospective study provides data on the prevalence of same-day pegfilgrastim administration in US clinical practice. Despite dosing guidance on the pegfilgrastim label and prior research, an important minority of patients are receiving same-day prophylaxis. A future study will evaluate clinical outcomes in this study population.
Table 1 Breast Cancer Colorectal Cancer Lung Cancer NHL No. of patients 33,076 1,251 12,888 10,433 Age, mean (SD), years 54.8 (10.3) 60.1 (11.3) 64.6 (9.9) 62.9 (13.7) Age < 65, % 84.7 68.5 53.3 56.5 Age ≥ 65, % 15.3 31.5 46.7 43.5 Male, % 0.0 42.9 54.2 54.2 Most common regimen, (%) AC/AC-T (27.4) FOLFOX (42.4) Carboplatin + paclitaxel (22.8) CHOP-R (62.1)
Abstract 4825. Table 2 Cycle 1 Cycles 2+ Day of Administration of Pegfilgrastim Prophylaxis*, % Day of Administration of Pegfilgrastim Prophylaxis*, % No. of Cycles Same Day Day 1 Days 2-3 Days 4-5 No. of Cycles Same Day Day 1 Days 2-3 Days 4-5 All cancer 49,028 13.4 68.5 16.3 1.8 195,659 13.0 69.8 15.7 1.5 Breast cancer 24,074 12.5 74.1 12.6 0.9 98,955 12.1 75.4 11.6 1.0 AC/AC-T 5,260 16.1 70.1 12.9 0.8 27,563 13.9 72.9 12.1 1.1 Colorectal cancer 563 19.7 22.4 43.2 14.7 3,920 8.1 19.1 66.9 6.0 FOLFOX 163 11.0 16.0 69.9 3.1 2,127 5.3 17.1 74.0 3.7 Lung cancer 9,184 11.7 62.4 24.5 1.4 29,434 11.9 61.3 25.5 1.4 Carboplatin + paclitaxel 2,223 11.1 72.7 15.1 1.1 5,977 12.0 74.1 13.1 0.9 NHL 7,814 13.0 70.4 15.6 1.0 30,067 12.4 73.1 13.5 1.0 CHOP-R 4,891 12.2 73.0 14.0 0.8 20,905 11.7 75.7 11.9 0.8
*Relative to last day of administration of myelosuppressive chemotherapy

Disclosures
Weycker: Amgen Inc.: Research Funding. Wu:Amgen Inc.: Research Funding. Hagiwara:Amgen Inc.: Research Funding. Li:Amgen Inc.: Employment, Equity Ownership. Barron:Amgen Inc.: Employment, Equity Ownership.