Impact of primary prophylaxis on febrile neutropenia within community practices in the US

Abstract

Objective: To determine if granulocyte-colony-stimulating factor (G-CSF) primary prophylaxis is associated with a lower risk of febrile neutropenia (FN) than non-primary prophylaxis.

Methods: This was a retrospective, cohort study of medical records from a random sample of patients with solid tumours and lymphomas treated in 99 community oncology practices in 2003 (n=5319). Consecutively-sampled patients treated with chemotherapy and either filgrastim (Neupogen), pegfilgrastim (Neulasta) or no G-CSF were included (n=3123). Multivariate logistic regression estimated the odds of FN in patients receiving G-CSF primary prophylaxis (within 3 days of first chemotherapy cycle) compared with non-primary prophylaxis (delayed or no G-CSF).

Results: Patients receiving primary prophylaxis were less likely to develop FN than patients receiving non-primary prophylaxis (OR=0.49, 95% CI 0.34–0.71, p<0.001). Chemotherapy characteristics were associated with development of FN including, receipt of at least three chemotherapy drugs versus one (OR=2.13, 95% CI 1.17–3.89, p=0.014) and regimens with at least one myelosuppressive drug (OR=2.37, 95% CI 1.19–4.73, p=0.014).

Conclusion: Patients receiving G-CSF primary prophylaxis had significantly lower odds of developing FN than those receiving non-primary prophylaxis. Incidence of FN may be underestimated, as care not recorded in the medical oncologist's chart was not captured.

Key words::

• febrile neutropenia
• filgrastim
• G-CSF
• growth factors
• pegfilgrastim

Acknowledgments

Declaration of interests: This research was sponsored by Amgen, Inc. J.L.M. has disclosed that she was an employee of Amgen at the time of this writing, but is still an Amgen stockholder; D.L.H. is an Amgen stockholder. M.W. and V.A.M. have no relevant financial relationships to disclose. The authors thank Beiying Ding for support in developing the statistical analysis plan and i3 Statprobe for conducting the statistical analyses.

Notes

*,† Neupogen and Neulasta are registered tradenames of Amgen Inc., Thousand Oaks, CA, USA.