NEULASTA (pegfilgrastim)

Drug overview for NEULASTA (pegfilgrastim):

Generic name: PEGFILGRASTIM (PEG-fil-GRA-stim)
Drug class: Leukocyte Stimulating Factors
Therapeutic class: Hematological Agents

Pegfilgrastim, a covalent conjugate of filgrastim and monomethoxypolyethylene glycol, is a biosynthetic hematopoietic agent that principally affects the proliferation and differentiation of neutrophils within the bone marrow. Pegfilgrastim-jmdb, pegfilgrastim-pbbk, pegfilgrastim-apgf, pegfilgrastim-fpgk, pegfilgrastim-cbqv, and pegfilgrastim-bmez are biosimilar to pegfilgrastim (Neulasta(R)). The US Food and Drug Administration (FDA) defines a biosimilar as a biological that is highly similar to an FDA-licensed reference biological with the exception of minor differences in clinically inactive components and for which there are no clinically meaningful differences in safety, purity, or potency.

The claim of biosimilarity is based on a totality-of-evidence approach, which includes consideration of data from analytical, animal, and clinical studies (e.g., human pharmacokinetic and pharmacodynamic studies, clinical immunogenicity assessment, additional comparative clinical studies). Therefore, biosimilarity of 2 drugs may be established even when there are formulation or minor structural differences or minor differences in rates of adverse effects between the drugs as long as these differences are not clinically meaningful. Biosimilars are approved through an abbreviated licensure pathway that establishes biosimilarity between the proposed biological and the reference biological but does not independently establish safety and effectiveness of the proposed biological.

In order to be considered an interchangeable biosimilar, a biological product must meet additional requirements beyond demonstrating biosimilarity to its reference product; these requirements include demonstrating that the biological product can be expected to produce the same clinical results as the reference product in any given patient and, for a biological product that is administered more than once to an individual, the risk in terms of safety or diminished efficacy of alternating or switching between use of the biological product and the reference product is no greater than the risk of using the reference product without such alternation or switch. Biosimilar products that are interchangeable can be substituted for the reference product without the intervention of the healthcare provider who prescribed the reference product. None of the available pegfilgrastim biosimilars have interchangeable data at this time. In this monograph, unless otherwise stated, the term ''pegfilgrastim products'' refers to pegfilgastrim (the reference drug) and its biosimilars (pegfilgrastim-jmdb, pegfilgrastim-pbbk, pegfilgrastim-apgf, pegfilgrastim-fpgk, pegfilgrastim-cbqv, and pegfilgrastim-bmez).

Several pegfilgrastim biosimilars are available and biosimilarity of these products has been demonstrated for the ability to decrease infection occurrence in patients with non-myeloid malignancies who are administered myelosuppressive chemotherapeutic agents associated with a clinically significant incidence of febrile neutropenia. Biosimilarity of all availablepegfilgrastim products has not been demonstrated for use in patients with acute exposure to myelosuppressive doses of radiation; only the reference pegfilgrastim (Neulasta(R)) and the biosimilar (pegfilgrastim-cbqv) are currently indicated for this use. Pegfilgrastim products are not indicated for use in the mobilization of peripheral blood progenitor cells for hematopoietic stem cell transplantation.

Clinical practice guidelines on the use of myeloid growth factors, such as pegfilgrastim, have been published. These guidelines focus on recommendations related to the use of these agents in reducing the risk of febrile neutropenia in patients at increased risk for associated complications. The American Society of Clinical Oncology (ASCO) guidelinespecifically states that pegfilgrastim and biosimilars (as they become available) can be used for the prevention of treatment-related febrile neutropenia and that the choice of agent depends on convenience, costs, and clinical situation.