Pegfilgrastim

Pegfilgrastim is a PEGylated form of the recombinant human granulocyte colony-stimulating factor (G-CSF) analogue, filgrastim. The drug is approved for use to decrease the incidence of infection, as manifested by febrile neutropenia, in susceptible patients with with non-myeloid cancer receiving myelosuppressive anti-cancer treatment. Although the risk of developing febrile neutropenia is less than 20% in many readily used chemotherapy regimens, infections pose risks of hospitalization and mortalities. Due to the relatively short circulating half-life of filgrastim, a 20 kDa PEG moiety was covalently conjugated to the N-terminus of filgrastim (at the methionine residue) to develop longer-acting pegfilgrastim. Due to a longer half-life and slower elimination rate than filgrastim, pegfilgrastim requires less frequent dosing than filgrastim; however, pegfilgrastim has a comparable pharmacological activity to filgrastim and binds to the G-CSF receptor to stimulate the proliferation, differentiation, and activation of neutrophils.

First developed by Amgen, pegfilgrastim was initially approved by the FDA in 2002 and marketed as Neulasta. It is typically administered via a subcutaneous injection. There are several pegfilgrastim biosimilars (Fulphila, Pelgraz or Lapelga, Pelmeg, Udenyca, Ziextenzo, Grasustek, Fylnetra, Stimufend) by Health Canada, European Union (EU), and FDA that are approved to reduce infection risk. These biosimilars are highly similar to the reference product, Neulasta, in terms of pharmacological and pharmacokinetic profile and conditions of use.

Pegfilgrastim is indicated to decrease the incidence of infection, as manifested by febrile neutropenia, in patients with non­ myeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a clinically significant incidence of febrile neutropenia.

It is also indicated to increase survival in patients acutely exposed to myelosuppressive doses of radiation (Hematopoietic Subsyndrome of Acute Radiation Syndrome).