Filgrastim (G-CSF)

Filgrastim was approved by the FDA in February 1991 to reduce the incidence of infection from febrile neutropenia in non-myeloid malignancies receiving myelosuppressive chemotherapy, and later for AML induction, bone marrow transplantation, peripheral blood progenitor cell mobilisation, severe chronic neutropenia and acute radiation syndrome. It was the first Amgen blockbuster and the model for supportive-care biologics; the first US biosimilar of any kind was filgrastim-sndz (Zarxio, 2015), and the EU authorised the first filgrastim biosimilars in 2008. Guidelines recommend primary prophylaxis when the febrile neutropenia risk of a regimen exceeds about 20%. Bone pain is the main adverse effect; splenic rupture, acute respiratory distress syndrome and sickle cell crises are rare but serious. Pegfilgrastim gives a once-per-cycle alternative.