Retrospective study evaluating the safety of administering pegfilgrastim on the final day of 5-fluorouracil continuous intravenous infusion.

Background: Pegfilgrastim, a long-acting granulocyte-colony-stimulating factor used to prevent neutropenia, is not indicated for administration within 24 h of completion of chemotherapy. The safety of administering pegfilgrastim in gastrointestinal cancer chemotherapy regimens containing continuous intravenous infusion of 5-fluorouracil (5-FUCI) on the day of completion of 5-fluorouracil has not been adequately studied.

Methods: An institutional review board-approved retrospective analysis of patients with a gastrointestinal malignancy receiving pegfilgrastim on the final day of 5-FUCI was conducted. The primary end point was to determine the incidence of grade 3 and grade 4 neutropenia and febrile neutropenia when pegfilgrastim was administered on the final day of 5-FUCI. The secondary endpoint was to determine rate of dose reductions and treatment delays.

Results: A total of 300 patients were reviewed from January 2010 to May 2017. The most common cancers were colorectal (25%) and pancreatic (60%), with 77% of patients having late stage disease. The risk of a patient developing grade 3 neutropenia was 0.010 (95% CI 0.002-0.029) and grade 4 neutropenia was 0.007 (95% CI 0.001-0.024). The risk of febrile neutropenia was 0.007 (95% CI 0.001-0.024). The risks of treatment delay and treatment reduction were 0.013 (95% CI 0.004-0.034) and 0.010 (95% CI 0.002-0.029), respectively.

Conclusion: The low risk of grade 3 and grade 4 neutropenia, febrile neutropenia, as well as dose delays and/or reduction suggests that pegfilgrastim can be administered on the final day of 5-FUCI. Limitations of this study were that it was retrospective in nature and was conducted at a single institution.