Biosimilar

A biosimilar (also known as follow-on biologic or subsequent entry biologic) is a biologic medical product which is almost an identical copy of an original product that is manufactured by a different company. Biosimilars are officially approved versions of original "innovator" products, and can be manufactured when the original product's patent expires. Reference to the innovator product is an integral component of the approval.

Unlike with generic drugs of the more common small-molecule type, biologics generally exhibit high molecular complexity, and may be quite sensitive to changes in manufacturing processes. Follow-on manufacturers do not have access to the originator's molecular clone and original cell bank, nor to the exact fermentation and purification process, nor to the active drug substance, although they do have access to the commercialized innovator product. Overall, it is harder to ascertain fungibility between generics and innovators among biologics than it is among totally synthesized and semisynthesized drugs, which is why the name "biosimilar" was coined to differentiate these drugs from small-molecule generics. A simple analogy is that it is harder to say that two wines are "sufficiently interchangeable", because of differences in yeast strain, weather, grape harvest, or terroir, than it is to say that two soda pops are "sufficiently interchangeable" because they contain the same flavoring powder and salts.

Drug related authorities such as European Medicines Agency (EMA), Food and Drug Administration (FDA), and Health Canada hold their own guidance on requirements for demonstration of the similar nature of two biological products in terms of safety and efficacy. According to them, analytical studies that demonstrate that the biological product is highly similar to the reference product notwithstanding minor differences in clinically inactive components, animal studies (including the assessment of toxicity), and a clinical study or studies (including the assessment of immunogenicity and pharmacokinetics or pharmacodynamics) are sufficient to demonstrate safety, purity, and potency in one or more appropriate conditions of use for which the reference product is licensed and intended to be used and for which licensure is sought for the biological product.

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