The Real-World Experience of the Biosimilar (Grastofil(®)) to the Reference Biologic (Neupogen(®)) in Breast Cancer and Lymphoma: A Canadian Single-Centre Retrospective Study

Febrile neutropenia (FN) is a common side effect of cytotoxic chemotherapy that may result in poor treatment outcomes. The short acting granulocyte colony stimulating factors (G-CSF) act to stimulate granulocytes to increase production of white blood cells. The filgrastim biosimilar is useful, as it may provide a cheaper and equally effective treatment to FN. This study explored the usage of the filgrastim biosimilar (Grastofil(®)) and the reference biologic (Neupogen(®)) in breast cancer and lymphoma patients. A retrospective chart review of patients receiving Grastofil(®) from January 2017 to June 2019 or Neupogen(®) for primary prophylaxis of FN from January 2013 to December 2017 was conducted. The endpoints included the incidence of FN and the occurrence of dose reduction (DR) and dose delay (DD). One hundred and fifty-three Grastofil(®) patients were matched to 153 Neupogen(®) patients. This cohort was further split into breast cancer (n = 275) and non-Hodgkin’s lymphoma (n = 31) cohorts. After adjusting for chemotherapy cycles, the biosimilar filgrastim was non-inferior to the reference biologic based on FN incidence in addition to related outcomes including DR and DD.