Monoclonal antibody (mAb) products are known to be prone to molecular instabilities like aggregation, fragmentation, oxidation, and reduction. Aggregation is a major issue for the advancement of marketed biotherapeutics products which can induce adverse immune responses in patients that may affect safety and efficacy. Though therapeutic formulations are designed to stabilize the product and minimize product degradation, aggregation is unavoidable and continues to be a concern for manufacturers of protein based therapeutic products. Aggregate particles of various sizes and morphologies are formed when subjected to physical, mechanical, and/or chemical stresses. These stresses may be experienced during manufacturing, storage, filling, formulation development and shipping. While there is widespread consensus that protein aggregation can enhance immunogenicity, the underlying immunological and biological mechanisms are not completely understood. A better understanding of protein aggregation can be gained by developing robust analytical techniques for monitoring level as well as nature of the aggregates. This study investigates how mAb aggregates generated by a variety of mechanical, thermal and chemical stresses impact the biological activity of a biotherapeutic. Increased aggregation resulted in a decrease in biological activity, as confirmed by cell based assays such as antibody dependent cell mediated cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) and ligand binding assays such as surface plasmon resonance (SPR). It was observed that aggregates formed due to extreme pH (pH 3.5 and pH 11.0), stirring (1 d stir and 3 d stir), thermal stress, and oxidation via CuSO4 have the most impact on potency of the therapeutic. In contrast, aggregates formed due to stresses from pipetting, milder pH (4.3 and 8.5), oxidation via H2O2, freeze-thaw (Ft-slow and Ft-fast) have relatively less impact on the potency of the mAb biotherapeutic. The results affirm that understanding of the mechanism of aggregation is critical for achieving consistent product quality and the resulting efficacy.

Impact of therapeutic mAb aggregation on its biological activity

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.