Reference Protocol to Assess Analytical Performance of Higher Order Structural Analysis Measurements: Results from an Interlaboratory Comparison

Measurements of protein
higher order structure (HOS) provide important
information on stability, potency, efficacy, immunogenicity, and biosimilarity
of biopharmaceuticals, with a significant number of techniques and
methods available to perform these measurements. The comparison of
the analytical performance of HOS methods and the standardization
of the results is, however, not a trivial task, due to the lack of
reference protocols and reference measurement procedures. Here, we
developed a protocol to structurally alter and compare samples of
somatropin, a recombinant biotherapeutic, and describe the results
obtained by using a number of techniques, methods and in different
laboratories. This, with the final aim to provide tools and generate
a pool of data to compare and benchmark analytical platforms and define
method sensitivity to structural changes. Changes in somatropin HOS,
induced by the presence of zinc at increasing concentrations, were
observed, both globally and at more localized resolution, across many
of the methods utilized in this study and with different sensitivities,
suggesting the suitability of the protocol to improve understanding
of inter- and cross-platform measurement comparability and assess
analytical performance as appropriate.