Brand Name: Neulasta
Generic name: pegfilgrastim
Medication Class: CSF (colony stimulation factor), hematopoetic agent
Similar Drugs: Neupogen (filgrastim), Granix (Tbo-filgrastim), Leukine (sargramostin)
Manufacturer: Amgen Inc.
FDA Approval Date: January 31, 2002
What is Neulasta and its mechanism of action?
Neulasta (pegfilgrastim) is a neupogen (filgrastim) that has been conjugated to polyethylene glycol (PEG). Compared to Neupogen, pegfilgrastim, is metabolized much slower, thus stays in the body longer than filgrastim. Filgrastim is recombinant human G-CSF (granulocyte-stimulating factors). G-CSF is found in the bone marrow and it stimulates the production of neutrophils. Neutrophils are a type of white blood cell (WBC) that is part of the body’s immune system which fights infections. Neulasta binds to a specific receptor on hematopoietic cell (blood forming cell), which will stimulate the production, maturation, and activation of neutrophils.
What is Neulasta used for treating?
A common adverse effect of chemotherapy is neutropenia (a low neutrophil or WBC count). Neulasta is FDA approved for preventing chemotherapy-induced febrile neutropenia in patients with non-myeloid malignancies. Severe neutropenia is defined by American Society of Clinical Oncology as fever > 101o F (38.3o C) sustained for >1 hour and absolute neutrophil count (ANC) <500 cells per microL.
Neulasta is also used during autologous stem cell transplantation to harvest peripheral blood stem cells. This is a non-FDA approved indication.
How effective is Neulasta?
Neulasta was evaluated in three randomized, double-blinded, controlled studies. The primary endpoint of the study was to establish that Neulasta is no less effective than filgrastim by measuring the number of days a patient is in severe neutropenia after chemotherapy. If the difference in the number of days in severe neutropenia (between the filgrastim groups and the Neulasta group) is less than 1 day, then it was considered to have met the efficacy outcome as illustrated in studies one and two below.
In study one, a single subcutaneous injection of Neulasta (6 mg) was compared to filgrastim 5 mcg/kg/day subcutaneous injection. The Neulasta group had an average of 1.8 days of severe neutropenia compared to 1.6 days for the filgrastim group.
In study two, Neulasta 100 mcg/kg/day was compared to filgrastim 5 mcg/kg/day. The Neulasta group had an average of 1.7 days of severe neutropenia compared to 1.6 days for the filgrastim group.
In study three, a single shot of Neulasta (6 mg) was compared to placebo. The placebo group had a higher incidence of febrile neutropenia (1% versus 17%), hospitalization (1% versus 14%) and more intravenous antibiotic (2% versus 10%) were used during treatment.