A short glance on Biosimilars
Autor: Eva Ballester Roig
It is well known that the European Union has been pioneer in providing a legal framework for biosimilars. The first biosimilar of the European Union was approved in 2006 and, still now, the major number of biosimilars worldwide are being approved by the European Medicines Agency.
For those not yet familiar with this up growing field of the medicine, a clear approach can be provided by the guides prepared by the European Medicines Agency, such as the “Information guide for healthcare professionals” on biosimilars in the EU. This document has been prepared by the European Medicines Agency and the European Commission together with the assistance of scientific experts from the European Union Member States. A short glance on relevant concepts defined in this guide is of great assistance:
What is a biological medicine?
It is a medicine where the active substance contained therein comes not from chemical products but from a biological source such as living cells or organisms. These living cells or organisms are modified by biotechnology (that is, technology which uses biological systems or living organism to create/ modified products or processes for specific uses). Biological medicines are more complex in structure and composition than the conventional medicines with chemical substances and therefore the cost their development is extremely higher.
Biological medicines are used to treat serious diseases such as cancer of inflammatory diseases. Hormones (for instance insuline to treat diabetes), and antimonoclonal bodies (to treat cancer and autoimmune diseases) are examples of biological medicines. Biological medicines are commonly presented as injectable.
What is a biosimilar?
A biosimilar is a biological medicine highly similar to another, already approved and marketed biological medicine, (the reference medicine). In particular the biosimilar has physical, chemical and biological properties highly similar to the reference medicine. It has the same posology and route of administration than the reference medicine.
Due to the natural variability of the biological source and to the manufacturing process unique to each manufacturer, minor differences may occur between the biosimilar and its reference medicine. However, any difference between the reference medicine and the biosimilar does not have any effect on quality, safety and efficacy.
What is the difference between biosimilar and a generic medicine?
Some of the main difference between a biosimilar and a generic are the following.
- It is not possible to obtain exact replication of the reference medicine: due to the natural variability and the more complex manufacturing process it is not possible to obtain an exact replication as it is possible in the generic medicine.
- Molecules involved in the generic medicines are generally small molecules and easy to characterize but biosimilars are larger and structurally more complex molecules which require multiple technology for its characterization and more studies are needed to obtain regulatory approval.
- More data requirements and further studies in the development are required in biosimilars:
- Not only full data on pharmaceutical quality (as in the generic medicine) but also additional studies comparing structure and biological activity of the biosimilar with the reference medicine.
- Development is based in the demonstration of biosimilarity using comparable studies to show high similarity in chemical structure, biological function, efficacy, safety and immunogenicity.
- The cost of development of a biosimilar medicine is extremely higher than the cost of development of a generic medicine.
What is immunogenicity?
When referring to biological medicines or biosimilar medicine it is extremely important to evaluate the immunogenicity of such medicines. The immune system has the ability to recognize foreign proteins and react against them. As biological medicines/biosimilars are obtained from biological sources, there is an intrinsic ability of such sources to cause an unwanted immune response of the body. However, this occurs in rare occasions and when it occurs are rarely severe. Also, antibodies directed against the biological medicine may neutralize the medicine’s activity and reduce its efficacy.
Immunogenicity may be influenced by the product characteristics or by the treatment related factors (subcutaneous v. intravenous administration, continuous versus intermittent treatment) or patient or disease related factors (age, genetic and immune status).
All in all, we do need to become familiar with these concepts as the new therapeutically routes opened by the biotechnology are and will be crucial in the future to treat very severe and severe diseases.