The EMA guideline covering analytical considerations of biosimilars recommends the application of extensive state- of-the-art characterisation studies, in order to demonstrate with a high level of assurance that the quality of biosimilars is comparable to their reference medicinal product.
The EMA recognises that “for some analytical techniques, a direct or side-by-side analysis of the biosimilar and reference medicinal product may not be feasible or give limited information (e.g. due to the low concentration of active substance and/or the presence of interfering excipients such as albumin). Samples might be prepared from the finished product (e.g. extraction, concentration, and/or other suitable techniques) and this poses the first significant hurdle that has to be overcome in terms of providing analytical data to support a claim of biosimilarity.
A number of innovator products are formulated at low concentration with relatively high concentrations of protein, amino acid, mono- and di-saccharide and/or surfactant stabilisers. All of these common excipients can and will interfere with the analytical data obtained.