Objectives: Prophylaxis with granulocyte colony-stimulating factor (G-CSF) reduces the severity of chemotherapy-induced neutropenia. Biosimilar G-CSF is now approved for use, based on comparable efficacy, safety and quality with the originator product.
Methods: We conducted a retrospective review of patients' charts following the switch from originator G-CSF (Neupogen(®)) to biosimilar G-CSF (Zarzio(®)/Filgrastim Hexal(®)) in a large community oncology practice. A total of 77 consecutive patients with cancer who received biosimilar G-CSF were reviewed, as were 25 patients who received originator G-CSF at the same centre.
Results: The median age of patients in the biosimilar G-CSF cohort was 67 years (range 20-83). In this cohort 48% had chemotherapy with a febrile neutropenia risk of >20%. Biosimilar G-CSF was given as primary prophylaxis in 52% and as secondary prophylaxis in 48% of patients. Age and febrile neutropenia in medical history or in previous chemotherapy were factors that triggered the use of G-CSF in patients with a febrile neutropenia risk of <20%. One patient developed febrile neutropenia. Neutropenia led to chemotherapy dose reductions in five patients (6.5%) and discontinuation in two patients (2.5%). No unexpected safety findings were observed. Patient characteristics were generally similar in the originator G-CSF cohort. Only 24% of patients had a febrile neutropenia risk >20% and 36% received primary prophylactic G-CSF. One patient developed febrile neutropenia. Neutropenia led to chemotherapy dose reductions in two patients (8%) and discontinuation in two patients (8%).
Conclusions: Biosimilar G-CSF was effective and prevented dose reductions/discontinuation in the majority of patients. Biosimilar G-CSF was considered clinically comparable to its reference product.
Keywords: biosimilars; chemotherapy; granulocyte colony-stimulating factor; neutropenia.