8 Things to Know About Biosimilars

Anya Romanowski, MS, RD


November 23, 2016

With the recent US Food and Drug Administration (FDA) approval of a fourth biosimilar medication, these compounds remain a hot topic in many areas of medicine, including nephrology,[1] oncology, endocrinology, gastroenterology, and rheumatology, as attested by the several biosimilar trials presented at the recent American College of Rheumatology Annual Meeting.

Despite the growing body of knowledge about biosimilars—and despite their increasing coverage in peer-reviewed journals and presentations—a recent Biosimilars Forum press release reveals that more physician education is needed about these medications. Areas in which it appears education can be improved include being able to define a biosimilar; understanding the FDA's approval process; and understanding the safety and efficacy of biosimilars, as well as their interchangeability with originator biologics.[2]

Given the remaining uncertainty about biosimilars, Medscape has put together a guide to better understand these agents.

What Are Biosimilar Medications?

Biosimilars are medicines that contain an active drug substance that is derived from or composed of a living organism highly similar to an existing FDA-approved biologic (known as the "reference product"). Notwithstanding minor differences in clinically inactive components between the two types of medications, the biosimilar must have no clinically meaningful differences from the reference product in terms of quality, safety, or efficacy.

A biosimilar is made available by a different pharmaceutical company from the originator when the patent and exclusivity expire on the original reference product. A biosimilar is not considered a generic drug, because it is not chemically synthesized.

What Is the Approval Process of Biosimilars?

Because biosimilars were only introduced into the market in the past decade, the process by which they are tested and approved is continually being refined and updated. Regulatory authorities, including the FDA, the European Medicines Agency (EMA), and the World Health Organization (WHO), have implemented unique measures for approving biosimilars, recognizing that their process for approving generic drugs cannot be applied to the licensing of biosimilars. The main differences among the authorities relate to the choice of the originator biologic and how the clinical indications are extrapolated.

The FDA follows a "totality of the evidence" process that is similar to the EMA's stepwise approach, and will approve a biosimilar if it has the same mechanism of action and is used for the conditions previously approved for the reference product. The route of administration, dosage form, and strength of both products need to be the same. The facility in which the biosimilar is manufactured, processed, packed, or held must meet the same standards as the one where the original reference product is manufactured, to ensure that it continues to be safe, potent, and pure.

The EMA's classification of biosimilarity is "a biological medicinal product that contains a version of the active substance of an already authorized original product (reference medicinal product)," whereas the WHO classifies it as "a biotherapeutic product that is similar in terms of quality, safety and efficacy to an already licensed reference biotherapeutic product."

The EMA's approval process of biosimilars is based on demonstrating the comparability to the reference product and follows a stepwise procedure of evaluating the reliability of physiochemical, biological, and nonclinical in vitro data. Once approved, manufacturers are required to implement a meticulous program for monitoring efficacy and appropriately managing safety risks.[3]


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