Filgrastim (ReliGrast) is a granulocyte colony-stimulating factor (G-CSF), a haematopoietic growth factor that stimulates the development of granulocytes. It is used to treat or prevent neutropenia in patients receiving myelosuppressive cancer chemotherapy and to reduce the period of neutropenia in patients undergoing bone marrow transplantation. It is also used to mobilize peripheral blood progenitor cells for use as an alternative to bone marrow transplantation, in the management of chronic neutropenia (congenital, cyclic, or idiopathic), and for persistent neutropenia in patients with advanced HIV infection.