Biosimilars are copies of biotechnology-derived pharmaceuticals, in a similar manner to generic drugs, but requiring a considerably higher standard of testing for proof of similarity in terms of efficacy and safety.
Biologically derived pharmaceuticals are significantly more complex and bigger (about 1000 fold) compared to traditional “small molecule” medicines, which raises their therapeutic power to a higher level. Biologics are typically produced by living cells. A demonstration of complete identity in terms of efficacy and safety to the reference product is therefor considered technically unfeasible by regulatory authorities even though the amino acid sequence is required to be identical in most cases. This is reflected by the term “biosimilar”.
To address this, the registration process of biosimilars requires non-clinical and clinical testing in comparison to the reference product, beyond the limited bioequivalence-testing sufficient for small molecule generic drugs.
Technically, biosimilars share the same base amino acid sequence, often the same host cell type and occasionally even parts or all of the manufacturing process and technology as the originator product.
In a number of countries biosimilars are considered substitutable for the originator drug while in other countries extensive additional safety and efficacy testing can be required by local authorities prior to considering the product to be substitutable.