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Switching between a reference product and a biosimilar





A biosimilar is a copy of a reference product previously approved in the EU (1). It can be used in the same therapeutic indications as the reference drug.

Biosimilars were first introduced in the EU in 2006.

The approval of biosimilars are based on the notion that there are no differences compared to the reference product, either in terms of quality, safety and efficacy (2). Adverse reactions have not been observed due to switching between reference products and biosimilars, or switching between biosimilars to the same reference drug. There are no scientific grounds to assume that adverse reactions should occur because of switching (3).

Switching during treatment

The position of the Norwegian Medicines Agency is that switching between reference products and biosimilars during ongoing treatment, is safe. It can apply to the following situations:

  • Switching from reference drug to biosimilar.

  • Switching from biosimilar to reference drug.

  • Switching from a biosimilar to another biosimilar based on the same reference product.

Further clinical studies confirming safety of switching are considered unnecessary. The decision on switching products is made by the treating physician or hospital, who have to provide the necessary information to patients. All patients treated with biological drugs must receive the necessary follow-up. To ensure traceability, adverse reactions with biological drugs should be reported with the drug name, active substance and batch number.

Why switching?

Switching is necessary to achieve competition between equally efficient drugs. Competition leads to price reductions that reduce the financial burden of expensive biological drugs in the healthcare system.

Automatic substitution in pharmacies?

In Norway, automatic substitution in pharmacies of biosimilar products is allowed.

You can read more about this here (only in Norwegian):

Biotilsvarende legemidler kan byttes i apotek


1. Weise M, Bielsky MC, De Smet K, Ehmann F, Ekman N, Giezen TJ et al. Biosimilars: what clinicians should know. Blood 2012; 120: 5111-7. doi: 10.1182 / blood-2012-04-425744.


European Medicines Agency, European Commission. Biosimilars in the EU. Information Guide healthca e professionals. (2017)


Kurki P, van Aerts L, Wolff-Holz E, Giezen T, Skibeli V, Weise M. Interchangeability of biosimilars: A European Perspective. BioDrugs 2017. DOI 10.1007 / s40259-017-0210-0

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