Treatment of Chemotherapy-Induced Granulocytopenia
Primary Prophylaxis
- The American Society of Clinical Oncology recommends initiating filgrastim when chemotherapy regimens carry >20% risk of febrile neutropenia 1
- Filgrastim should be started 24-72 hours after the last chemotherapy dose, never on the same day as chemotherapy, due to increased risk of severe thrombocytopenia and febrile neutropenia 1, 2
- The standard dose of filgrastim is 5 mcg/kg/day subcutaneously, and it should be continued daily until post-nadir ANC reaches 2,000-3,000/mm³ 1, 2
- Pegfilgrastim 6 mg as a single subcutaneous dose per cycle is equally effective to 10-11 days of daily filgrastim, but should not be used in patients <45 kg 2
Therapeutic Use
- The National Comprehensive Cancer Network recommends considering filgrastim 5 mcg/kg/day subcutaneously in febrile neutropenic patients only if high-risk features are present, such as severe neutropenia, anticipated prolonged neutropenia, sepsis syndrome, or pneumonia 1, 6
- Filgrastim does not reduce mortality in febrile neutropenia, but it shortens neutropenia duration and hospitalization 6
- The European Society for Medical Oncology recommends against routine use of filgrastim in afebrile neutropenic patients, as it does not reduce hospitalization, antibiotic use, or infection rates in this population 4, 5
Absolute Contraindications
- The American College of Clinical Pharmacy recommends never administering filgrastim during concurrent chest/thoracic radiotherapy, within 24 hours before or simultaneously with chemotherapy, or in patients without neutropenia 3, 1, 2
Special Populations
- The American Society of Hematology recommends against routine use of filgrastim in pediatric AML/ALL patients due to theoretical concerns about stimulating leukemic blast growth 1, 2
- Filgrastim may be safely delayed until day 5-7 post-transplant in allogeneic bone marrow transplantation 2