Intertek ASG Laboratory, Manchester, UK

Biopharmaceutical Comparability Studies

Comparability studies are of major importance in the development of biopharmaceuticals. For new products, such studies may be needed to qualify sources of clinical trial materials following process development, optimization, and scale up as progress through the clinical development phases is made. The demonstration of equivalence to materials used in toxicology and early phase clinical trials is necessary to avoid bridging toxicology or clinical trials which would clearly add significantly to drug development timescales and costs. Comparability studies are also key to the development of biogenerics or biosimilars.

Intertek ASG is highly experienced in the biophysical characterization of a diverse range of biopharmaceuticals and has undertaken detailed comparability sutides. There is a regulatory expectation that “orthogonal” approaches will be applied such that conclusions for key quality attributes are based on multiple technologies. Recent projects have included comparing the study materials using the following approaches:

Primary Structure

Molecular weight by MALDI-MS, electrospray MS and LCMS
Amino acid composition
Peptide mappng by protease digestion followed by LCMS, LCMSMS and MALDI-MS (this typically also provides the N- and C- terminal sequence information)

Post Translational Modifications

Disulphide bridge mapping using protease digest and chemical modification experiments followed by MALDI-MS
Free thiol determination
Glycosylation detection and fingerprinting using acid hydrolysis followed by anion exchange chromatography with electrochemical detection
Characterisation of other PTMs including deamidation, acetylation and phosphorylation

Chromatographic Profiles

Profiles generated for each sample using LCMS, reducing and non-reducing gel electrophoresis,
horizontal and vertical gel isoelectric focusing and capillary isoelectric focusing

Secondary/Tertiary Structure

Determination of secondary structural attributes (α-helix, β-sheet, β-turns) using FTIR and circular dichroism (CD)†
NMR studies using 500 MHz instrument to compare the behaviour of samples when stressed by heating, resulting in loss of secondary and/or tertiary structure and precipitation

Quaternary Structure/Aggregation State

SEC-MALLS and Analytical Ultra Centrifugation (AUC†) studies
Imaging of aggregates using electron microscopy following immuno-gold labelling
Fluorescence studies of behaviour under denaturing conditions such as heat or urea

†CD and AUC data is generated in partner laboratories following QA audit and can be included in formal regulatory studies and in conclusions drawn across multiple techniques