Prescribers,
pharmacists,
payers and
patients should
feel confident in
the sound,
scientific
approaches taken
to evaluate and
approve
biosimilars
support a switch from originator to biosimilar, if
certain conditions are fulfilled by the drug. Different
immunogenic responses of the patient to the drug
are dependent on the drug’s quality characteristics,
but not on the patient him/herself because the
genetic background and nature of the disease
is similar before and after switching. To further
complicate this issue, immunogenicity is not only
due to the drug, because other factors such as the
status of disease and how the drug is administered
can play a role, but also because clinicians are
sometimes more concerned with the safety profile
of the drug and how the different production
process of a biosimilar affects the risk of the patient
experiencing adverse events. 22
Interchangeability and the issue of switching
Interchangeability implies that a biologic can be
replaced by the biosimilar without intervention of
the prescriber. However, there are discrepancies
between countries about what constitutes an
interchangeable product. Whereas the US Food and
Drug Administration (FDA) might approve a product
as such, the EMA does not to designate a product
as interchangeable, with decisions regarding
interchangeability occurring at the national level.
FDA guidelines require that a biosimilar should
produce the same outcome as the originator,
without increased safety risks or reduced efficacy
when switching from the reference product to
the biosimilar. Once a product is approved as
interchangeable, it becomes possible to substitute
the reference product with the biosimilar. 23
As explicitly defined by the guidelines pertaining
to biosimilars, the data supporting biosimilarity
are not only based on quality, but also on clinical
confirmation. By contrast, the assessment of quality
differences is not a relevant question in the clinical
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