The problem for physicians, and therefore for medical societies, is that biosimilars can never be exact copies of their reference products. Many physicians worry that if a reference product and its biosimilar are not structurally identical they might not be therapeutically equivalent.

The problem is particularly evident in a naturally relapsing/remitting disease like rheumatoid arthritis (RA). A patient who starts taking a biosimilar, in place of the reference product they were prescribed originally, and suffers a relapse of symptoms may well blame the symptoms on the biosimilar. Physicians might not always be confident explaining that this is unlikely – given the comparability studies to which each biosimilar will have been subject.

The problem, suggests Professor Pekka Kurki of the Finnish Medicines Agency, Fimea, Finland, is that while regulators decide what constitutes a biosimilar based on analytical and non-clinical testing and clinical trials as one package (the totality of evidence), clinicians focus on clinical testing only.

Professor Kurki, who chaired a GaBI Roundtable on Biosimilars in Brussels earlier this year [1], says that this explains a lack of confidence in comparability among clinicians. Regulators are confident because they have been carrying out studies like these for over two decades for manufacturing changes to the same drug. Many changes are routinely made to the manufacturing process of individual products after they have been approved, a fact that is not fully understood – or even known about – by most clinicians.

For specialist clinicians, it is difficult to accept that studies performed in one disease can be applied to another disease with different pathogenic features. Regulators, meanwhile, are focussed on receptor binding of the biosimilar, i.e. the mode of action of the active substance. It is important to recognize that biosimilars have a proven similarity without being identical to the reference product.

The position papers published by medical societies share one common concern: physician autonomy. Physicians need to make their own therapeutic decisions. ‘That is understandable, and we support that’, said Professor Kurki. ‘But there are economic realities, and the question is how to apply prescribing autonomy in the best way for the benefit to patients and healthcare systems’.

The next article discusses the benefits of biosimilars need to be communicated.

Editor’s comment
This article for GaBI Online is a series of two articles prepared from the full manuscript published in GaBI Journal.

If you would like to receive a copy* of the GaBI Journal manuscript [1], please send us an email.

Readers interested to learn more about biosimilars for prescribers are invited to visit www.gabi-journal.net to view the following manuscript published in GaBI Journal:

Biosimilars for prescribers

If you are interested in contributing a research paper in a similar area to GaBI Journal, please send us your submission here.

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Related articles
Biosimilars: the benefits need to be communicated

Half of doctors not convinced about biosimilars

Clinical and regulatory issues for biosimilars

Reference
1. Annese V, Avendaño-Solá C, Breedveld F, Ekman N, Giezen TJ, Gomollón F, et al. Roundtable on biosimilars with European regulators and medical societies, Brussels, Belgium, 12 January 2016. Generics and Biosimilars Initiative Journal (GaBI Journal). 2016;5(2):74-83. doi:10.5639/gabij.2016.0502.019

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