BACKGROUND: The timing of prophylactic pegylated granulocyte colony-stimulating factor (G-CSF) administration during cancer chemotherapy varies, with Day 2 and Days 3-5 being the most common schedules. Optimal timing remains uncertain, affecting efficacy and adverse events. This systematic review sought to evaluate the available evidence on the timing of prophylactic pegylated G-CSF administration.
METHODS: Based on the Minds Handbook for Clinical Practice Guideline Development, we searched the PubMed, Ichushi-Web, and Cochrane Library databases for literature published from January 1990 to December 2019. The inclusion criteria included studies among the adult population using pegfilgrastim. The search strategy focused on timing-related keywords. Two reviewers independently extracted and assessed the data.
RESULTS: Among 300 initial search results, only four articles met the inclusion criteria. A meta-analysis for febrile neutropenia incidence suggested a potential higher incidence when pegylated G-CSF was administered on Days 3-5 than on Day 2 (odds ratio: 1.27, 95% CI 0.66-2.46, p = 0.47), with a moderate certainty of evidence. No significant difference in overall survival or mortality due to infections was observed. The trend of severe adverse events was lower on Days 3-5, without statistical significance (odds ratio: 0.72, 95% CI 0.14-3.67, p = 0.69) and with a moderate certainty of evidence. Data on pain were inconclusive.
CONCLUSIONS: Both Day 2 and Days 3-5 were weakly recommended for pegylated G-CSF administration post-chemotherapy in patients with cancer. The limited evidence highlights the need for further research to refine recommendations.

Evidence-based US guidelines provide recommendations for the use of granulocyte colony-stimulating factor (G-CSF) as supportive therapy in patients with cancer receiving chemotherapy. Pegfilgrastim is recommended for FN prophylaxis in patients with non-myeloid malignancies receiving a high-risk chemotherapy regimen, or an intermediate-risk regimen if one or more risk factors are present. The guidelines highlight the patient characteristics and chemotherapy regimens for solid tumors and hematologic malignancies that may influence a patient\'s overall risk of FN and may benefit from pegfilgrastim support. This review aimed to evaluate how pegfilgrastim use in patients with cancer receiving myelosuppressive chemotherapy in routine clinical practice aligns with evidence-based US guidelines. Examination of the literature revealed widespread deviation in relation to under- and over-prescribing, and timing of administration in US clinical practice. Pegfilgrastim is often over-prescribed in patients receiving palliative chemotherapy and those at low risk of FN. Potential under-prescribing of pegfilgrastim was also observed. In this literature search, data that appear to support same-day administration of pegfilgrastim were from uncontrolled studies that were limited in size. Analyses of healthcare claims data clearly favored next-day use, with statistically significant increases in FN incidence among patients receiving same-day pegfilgrastim versus those treated 1-4 days post-chemotherapy. Earlier-than-recommended administration typically occurs at the physician\'s discretion where next-day administration might present barriers to the patient receiving supportive therapy.There is a need to ensure appropriate prescribing to optimize patient outcomes, as deviation from the guideline recommendations was associated with increased incidence of FN and hospitalization.

Chemotherapy-induced febrile neutropenia (FN) causes treatment delays and interruptions and can have fatal consequences. Current guidelines provide recommendations on granulocyte colony-stimulating factors (G-CSF) for prevention of FN, but guidance is unclear regarding use of short- vs long-acting G-CSF (e.g., filgrastim vs pegfilgrastim/lipegfilgrastim, respectively). An international panel of experts convened to develop guidance on appropriate use of pegfilgrastim for prevention of chemotherapy-induced FN.
Guidance recommendations were developed following a literature review, survey, evaluation of current practice, and an expert meeting. Consensus was established using an anonymous Delphi-based approach.
Guidance recommendations for prevention of treatment-associated FN were as follows: for treatment with curative intent, maintenance of dose intensity using G-CSF to prevent dose delays/reduction should be standard of care; for treatment-associated FN risk ≥ 20%, short-acting G-CSF/pegfilgrastim should be given from cycle 1 onwards; and for treatment-associated FN risk < 20%, short-acting G-CSF/pegfilgrastim should be given if factors suggest overall risk (including treatment-related and patient-related risk factors) is ≥ 20%. It was agreed that pegfilgrastim and 11 days\' filgrastim have similar efficacy and safety and that pegfilgrastim is preferred to < 11 days\' filgrastim (and may be preferred to ≥ 11 days\' filgrastim based on adherence and convenience); pegfilgrastim is not appropriate in weekly chemotherapy; in split-dose chemotherapy, pegfilgrastim is recommended 24 h after last chemotherapy dose; and during palliative chemotherapy, patient adherence and convenience may favor pegfilgrastim.
In this era of targeted therapies, additional trials with G-CSF are still required. These recommendations should be used with existing guidelines to optimize pegfilgrastim use in clinical practice.