Febrile neutropenia (FN) and pegfilgrastim prophylaxis in breast cancer and non-Hodgkin's lymphoma patients receiving high (> 20%) FN-risk chemotherapy: results from a prospective observational study.

Purpose: Prophylaxis for febrile neutropenia (FN) is recommended for the duration of myelosuppressive chemotherapy in high-risk patients; yet, granulocyte-colony-stimulating factor (G-CSF) discontinuation occurs frequently in clinical practice. The objective of this study was to investigate the incidence of FN in real-world settings and the extent and impact of early pegfilgrastim discontinuation.

Methods: This prospective, observational study enrolled patients with any-stage non-Hodgkin's lymphoma (NHL) or breast cancer initiating a new chemotherapy course with a high (> 20%) FN risk, with pegfilgrastim in cycle 1. During routine clinical visits, data were collected on FN events, discontinuation of pegfilgrastim (defined as administration of G-CSF other than pegfilgrastim for ≥ 1 cycle) and all G-CSF (and reasons), neutropenic complications and adverse drug reactions (ADRs).

Results: Overall, 943 patients were enrolled; 844 met the eligibility criteria (full analysis set) and 814 (86%) completed the study. Twenty-eight patients (3%) had 31 FN events (NHL, n = 17; breast cancer, n = 11). Twenty-six patients (3%) discontinued pegfilgrastim. Forty-four patients (5%) discontinued G-CSF. The most common reason for pegfilgrastim discontinuation was physician preference for daily G-CSF (n = 14 [2%]), and for discontinuation of all G-CSFs was reduced FN risk (n = 14 [2%]). Patients who continued G-CSF prophylaxis were less likely to experience neutropenic complications (odds ratio [95% confidence interval]: 0.26 [0.09-0.80]). Suspected ADRs to pegfilgrastim occurred in 43 patients (5%) and serious ADRs in 5 (1%).

Conclusions: FN rates were consistent with previous reports with pegfilgrastim in clinical practice. No new ADRs were observed. G-CSF discontinuation was uncommon but appeared to increase the likelihood of neutropenic complications.