Granulocyte colony stimulating factors (G-CSF), including filgrastim and pegfilgrastim, are associated with bone pain, potentially impacting treatment adherence. This study hypothesized that a 5-day regimen of filgrastim (5-day-FIL) would result in less bone pain than single-dose pegfilgrastim (PEG) in patients receiving chemotherapy for early breast cancer. In this multicenter, open-label, randomized controlled trial, patients requiring prophylactic G-CSF during chemotherapy were randomized 1:1 to receive either 5-day FIL or PEG. The primary outcome was patient-reported bone pain, assessed as area under the curve (AUC) of daily pain scores (0 = no pain to 10 = worst pain) over the first 5 days following G-CSF in cycle 1. Secondary outcomes included bone pain in cycles 2-4, febrile neutropenia (FN), hospitalizations, chemotherapy delays, dose reductions, early discontinuations, chemotherapy-related deaths, health-related quality-of-life, and healthcare resource utilization. From June 2021 to March 2023, 233 patients were randomized, with 219 analyzed (110 FIL/109 PEG) after excluding those who withdrew before receiving treatment. Adjusting for stratification factors and prespecified baseline co-variates using repeated measures linear regression, the mean AUC (0 to 40) for cycle 1 bone pain was 10.2 (SD 11.2) for 5-Day-FIL and 10.2 (SD 9.81) for PEG, with an adjusted mean difference of 0.70 (95% CI: -1.62, 3.02; p = .556). While no significant differences were observed in most secondary outcomes, the 5-day-FIL group exhibited a numerically higher incidence of FN (6.4% vs 0.9%, p = .065) and hospitalization (10.0% vs 3.7%, p = .106). There was no significant difference in bone pain between 5-day-FIL and PEG.
Ng et al. (Thu,) studied this question.