Native peptide mapping - A simple method to routinely monitor higher order structure changes and relation to functional activity

NMR coupled with multivariate data analysis for monitoring the degradation of a formulated therapeutic monoclonal antibody

The function of a protein is directly coupled to its higher-order structure (HOS). Deviations in this critical quality attribute (CQA) may be linked to a decrease in the efficacy and/or safety of the final therapeutic product. High-resolution nuclear magnetic resonance (NMR) spectroscopy has been recently highlighted for protein HOS characterization, thanks to its ability to capture small changes at the molecular and structural levels (primary, secondary, tertiary and quaternary structures). The present study was carried out to demonstrate the ability of NMR (1D 1H and 2D 1H-13C experiments) coupled with multivariate data analysis (PCA and PLS regression) to monitor the degradation of a formulated mAb-like protein and for the simultaneous quantification of related CQAs, i.e., potency, purity and impurities (aggregates and fragments). The results indicate that this approach could be applied to mitigate product quality risks during development, manufacturing and stability studies of mAb therapeutics.

Biophysical Analysis of Therapeutic Antibodies in the Early Development Pipeline

The successful progression of therapeutic antibodies and other biologics from the laboratory to the clinic depends on their possession of "drug-like" biophysical properties. The techniques and the resultant biophysical and biochemical parameters used to characterize their ease of manufacture can be broadly defined as developability. Focusing on antibodies, this review firstly discusses established and emerging biophysical techniques used to probe the early-stage developability of biologics, aimed towards those new to the field. Secondly, we describe the inter-relationships and redundancies amongst developability assays and how in silico methods aid the efficient deployment of developability to bring a new generation of cost-effective therapeutic proteins from bench to bedside more quickly and sustainably.

Limited Proteolysis Coupled with Mass Spectrometry for Simultaneous Evaluation of a Large Number of Protein Variants for Their Impact on Conformational Stability

A stable molecular structure is important in the development of a protein candidate into a therapeutic product. A therapeutic protein often contains many different variants; some of them may have an impact on the conformational stability of the protein. Conventionally, to evaluate the impact of a variant on stability, the variant must be enriched to a reasonable purity, and then its stability characterized by chromatographic or biophysical techniques. However, it is often impractical to purify and characterize each variant in a therapeutic protein. A workflow, based on limited proteolysis followed by MS detection, was established to simultaneously assess the impact of a large number of variants on conformational stability without enrichment. Because a less stable domain is more susceptible to proteolytic degradation, conformational stability of the domain can be reported from the release rate of a proteolytic peptide. A kinetic model is established to quantitatively determine the extent of domain stabilization/destabilization of different variants. The methodology is demonstrated by examining variants known to affect the stability of immunoglobulin domains, such as different N-glycoforms, methionine oxidations, and sequence variants. With this methodology, near 100 variants may be evaluated within 2 days in a single experiment. Insights into the sequence-stability relationship will be obtained by monitoring the large number of low-level sequence variants, facilitating engineering of more stable molecules.

A multi-angular view on the impact of protein unfolding on biophysical structural data

The performance of biophysical methods used for the characterization of protein higher order structure (HOS) is key to ensure reliable structural data for drug applications, as these methods are not routinely validated. To assess the analytical performance characteristics, the impact of increasing amounts of heat-denatured material (HDM) on HOS data obtained for a monoclonal antibody (mAb) and its cysteine-conjugated antibody-drug conjugate (ADC) by a set of biophysical methods routinely used in the pharmaceutical industry was evaluated. Relationships between structural data generated by these methods were established using statistical correlation analysis. Most individual methods revealed a linear correlation with increasing amounts of HDM, in the presence of intact mAb or ADC. Overall, Pearson correlation analysis showed strong correlations between the biophysical data obtained. Moreover, biophysical methods that are generally claimed to be orthogonal, were confirmed to provide similar structural insights based on the data obtained. Some methods were capable of differentiating the impact of structural change and/or onset of protein aggregation between the mAb and the ADC. Our results underline the capabilities and performance of the biophysical characterization methods investigated, thereby substantiating these are 'scientifically sound' and 'fit for purpose': the interrogation of protein HOS as part of pharmaceutical development.