The Food and Drug Administration (FDA) has approved Releuko (filgrastim-ayow), a biosimilar to Neupogen® (filgrastim). The approval was based on data demonstrating that the biosimilar product and the reference product were highly similar, and that there were no clinically meaningful differences between the 2 agents.

Releuko, a leukocyte growth factor, is approved to:

  • Decrease the incidence of infection‚ as manifested by febrile neutropenia‚ in patients with nonmyeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a significant incidence of severe neutropenia with fever.
  • Reduce the time to neutrophil recovery and the duration of fever, following induction or consolidation chemotherapy treatment of patients with acute myeloid leukemia.
  • Reduce the duration of neutropenia and neutropenia-related clinical sequelae‚ eg‚ febrile neutropenia, in patients with nonmyeloid malignancies undergoing myeloablative chemotherapy followed by bone marrow transplantation.
  • Reduce the incidence and duration of sequelae of neutropenia in symptomatic patients with congenital neutropenia‚ cyclic neutropenia‚ or idiopathic neutropenia.

Releuko is supplied in single-dose vials and single-dose prefilled syringes containing 300mcg or 480mcg of filgrastim-ayow in a preservative-free solution. The product is expected to be available in the third quarter of 2022.


  1. Amneal enters US biosimilars market with approval of ReleukoTM (filgrastim-ayow). News release. March 2, 2022.
  2. Releuko. Package insert. Amneal. Accessed March 2, 2022.