A multicentre, randomised trial comparing schedules of G-CSF (filgrastim) administration for primary prophylaxis of chemotherapy-induced febrile neutropenia in early stage breast cancer
Authors: M. Clemons, D. Fergusson, D. Simos, M. Mates, A. Robinson, N. Califaretti, L. Zibdawi, M. Bahl, J. Raphael, M.F.K. Ibrahim, R. Fernandes, L. Pitre, O. Aseyev, C. Stober, L. Vandermeer, D. Saunders, B. Hutton, R. Mallick, G.R. Pond, A. Awan, J. Hilton
Journal: Annals of Oncology (2020)

•Multicentre randomised trial of 466 breast cancer patients compared schedules of filgrastim administration.•Provides real-world data showing filgrastim use beyond 5 days did not significantly improve co-primary or secondary outcomes.•5 days of filgrastim should be considered the standard of care. BackgroundThe optimal duration of filgrastim as primary febrile neutropenia (FN) prophylaxis in early breast cancer patients is unknown, with 5, 7 or 10 days being commonly prescribed. This trial evaluates whether 5 days of filgrastim was non-inferior to 7/10 days.Patients and methodsIn this randomised, open-label trial, early breast cancer patients who were to receive filgrastim as primary FN prophylaxis were randomly allocated to 5 versus 7 versus 10 days of filgrastim for all chemotherapy cycles. A protocol amendment in November 2017 allowed subsequent patients (N = 324) to be randomised to either 5 or 7/10 days. The primary outcome was a composite of either FN or treatment-related hospitalisations. Secondary outcomes included chemotherapy dose reductions, delays and discontinuations. Analyses were carried out by per protocol (primary) and intention-to-treat, and the non-inferiority margin was set at 3% for the risk of having FN and/or hospitalisation per cycle of chemotherapy.ResultsPatients (N = 466) were randomised to receive 5 (184, 39.5%), or 7/10 (282, 60.5%) days of filgrastim. In our primary analysis, the difference in risk of either FN or treatment-related hospitalisation per cycle was −1.52% [95% confidence interval (CI): −3.22% to 0.19%] suggesting non-inferiority of a 5-day filgrastim schedule compared with 7/10-days. The difference in events per cycle for FN was 0.11% (95% CI: −1.05 to 1.27) while for treatment-related hospitalisations it was −1.68% (95% CI: −2.73% to −0.63%). The overall proportions of patients having at least one occurrence of either FN or treatment-related hospitalisation were 11.8% and 14.96% for the 5- and 7/10-day groups, respectively (risk difference: −3.17%, 95% CI: −9.51% to 3.18%).ConclusionFive days of filgrastim was non-inferior to 7/10 days. Given the cost and toxicity of this agent, 5 days should be considered standard of care.ClinicalTrials.gov registrationNCT02428114 and NCT02816164. The optimal duration of filgrastim as primary febrile neutropenia (FN) prophylaxis in early breast cancer patients is unknown, with 5, 7 or 10 days being commonly prescribed. This trial evaluates whether 5 days of filgrastim was non-inferior to 7/10 days. In this randomised, open-label trial, early breast cancer patients who were to receive filgrastim as primary FN prophylaxis were randomly allocated to 5 versus 7 versus 10 days of filgrastim for all chemotherapy cycles. A protocol amendment in November 2017 allowed subsequent patients (N = 324) to be randomised to either 5 or 7/10 days. The primary outcome was a composite of either FN or treatment-related hospitalisations. Secondary outcomes included chemotherapy dose reductions, delays and discontinuations. Analyses were carried out by per protocol (primary) and intention-to-treat, and the non-inferiority margin was set at 3% for the risk of having FN and/or hospitalisation per cycle of chemotherapy. Patients (N = 466) were randomised to receive 5 (184, 39.5%), or 7/10 (282, 60.5%) days of filgrastim. In our primary analysis, the difference in risk of either FN or treatment-related hospitalisation per cycle was −1.52% [95% confidence interval (CI): −3.22% to 0.19%] suggesting non-inferiority of a 5-day filgrastim schedule compared with 7/10-days. The difference in events per cycle for FN was 0.11% (95% CI: −1.05 to 1.27) while for treatment-related hospitalisations it was −1.68% (95% CI: −2.73% to −0.63%). The overall proportions of patients having at least one occurrence of either FN or treatment-related hospitalisation were 11.8% and 14.96% for the 5- and 7/10-day groups, respectively (risk difference: −3.17%, 95% CI: −9.51% to 3.18%). Five days of filgrastim was non-inferior to 7/10 days. Given the cost and toxicity of this agent, 5 days should be considered standard of care.