[BLOG]: 5 things you need to know about biosimilars

ReedOn March 6, 2015, FDA approved Zarxio (filgrastim-sndz), the first biosimilar product to be approved in the United States. There are several other biosimilars under development and thus this is likely the first of many.

Given this, pharmacists will want to familiarize themselves with this new class of therapies. The Biosimilars Forum offers 5 top things that a pharmacist should know about biosimilars:

#1. A biosimilar is a biologic medicine that is developed to be highly similar to an existing biologic medicine (reference product), and has been shown to have no clinically meaningful differences from the reference product.

It is important to note, however, that a biosimilar is not the same as a generic. Generics have chemical structures that are simpler and are considered to be identical to their referenced medications. Biosimilars are made from living substances like biologics and thus may have a degree of natural variability. They may include the active substance of its reference biologic and deemed essentially the same biological substance, but may have minor differences because of their complex nature and production methods. All differences must be supported by a robust data package of comparative, analytical, pharmacological, and clinical data to demonstrate a highly similar standard to the reference biological product, and the same quality, safety, and efficacy.

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#2. A stepwise approach to biosimilars is followed, and the totality of evidence is reviewed holistically to determine there are no significant clinical differences.

This analytical testing demonstrates physical, chemical, and functional similarity to the reference biologic. This includes assessment of physicochemical properties; functional activities; receptor binding and immunochemical properties, screening for impurities; reference product and reference standards; finished drug product; and stability testing. Non-clinical studies evaluate comparative toxicity. Pharmacokinetic (PK) and pharmacodynamic (PD) studies demonstrate whether a proposed biosimilar stays in the body for the same amount of time, elicits the same response, and can be expected to be highly similar at multiple levels with no differences that are clinically relevant when compared to the reference biologic.

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#3. Robust analytical data is the foundation for establishing the totality of evidence for a biosimilar that is ultimately confirmed by the clinical data.

The safety and efficacy of the biosimilar is established by relying on the body of evidence developed by the reference biological product. The clinical data generated with the biosimilar includes and completes the link to the reference product. Thus, there is an understanding that the data generated with the reference biological drug product will also apply to the biosimilar.

#4. Extrapolation is critical for the success of biosimilars.

A biosimilar may be approved for 1 or more conditions of use for which the reference biological product is licensed. This is based on the extrapolation of data intended to demonstrate biosimilarity in one condition of use. The concept of extrapolation is an established principle in pharmaceutical development. The use of extrapolation data for a biosimilar has to be backed by sufficient evidence and scientific justification.

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#5. An interchangeable biological product, in addition to meeting the biosimilarity standard, has data to support the premise that it is expected to produce the same clinical result as the reference product in any given patient.

Biosimilars have no clinically meaningful difference in terms of safety and efficacy from the reference biologic they are compared to. Additionally, a biosimilar can only be approved for the indications and conditions of use that have been previously approved for the reference biologic. An interchangeable biological product, in addition to meeting the biosimilarity standard set by FDA, is expected to produce the same clinical result as the reference product in any given patient. A biosimilar is thus deemed interchangeable by FDA after careful review of the totality of the data that represents that the biosimilar will produce the same clinical result as the reference product in any given patient.

Juliana Reed is vice president, government affairs at Coherus Bioscience, Inc., and president of the Biosimilars Forum, a non-profit organization to advance biosimilars in the United States with the intent of expanding access and availability of biological medicines and improving healthcare.