Biosimilars: the paradox of sharing the same pharmacological action without full chemical identity.

The use of biotech medicines is increasing, with consequent mounting expenses for National Health Systems (NHSs). Biosimilars should be considered an opportunity to improve access to care. On the other side, the general public might suspect to receive low-quality medicines to save money. Actually, no drugs with a lesser degree of pharmaceutical quality with respect to existing alternatives can be authorized on the ground of a lower price. Biosimilars can be authorized only if their quality is of the same level as that of the originator. There is no chemical identity between biosimilars and the originators: any differences in quality attributes must be justified and shown not to impact on the safety and efficacy of the biosimilar by scientific investigations including pre-approval nonclinical and/or clinical studies. The biosimilar safety profile may be different from the originator or change over time for the same product. Hence caveats limiting the widespread use of biosimilars yet exist and should be solved by education on the main biological issues of biotech medicines, and on continuous update of the rules set up by the Regulatory Authorities to assess biosimilarity and to monitor post-approval safety.