Investigation of Immune Responses to Oxidation, Deamidation, And Isomerization in Therapeutic Antibodies using Preclinical Immunogenicity Risk Assessment Assays

Product- and process- related critical quality attributes have the potential to impact pharmacokinetics, immunogenicity, potency, and safety of biotherapeutics. Among these critical quality attributes are chemical degradations, specifically oxidation, deamidation, and isomerization. These degradations can be induced by stressors such as light, pH, or temperature; they can also occur naturally under normal conditions. The immunogenicity risk of chemical degradations, particularly in the absence of aggregation, has not been thoroughly understood. In this study, model antibodies with known labile residues were stressed to induce each of the three chemical degradation classes. Aggregate-free and chemically modified antibody species were fractionalized and characterized, followed by testing in standardized and qualified preclinical immunogenicity risk assessment assays for dendritic cell internalization and presentation, monocyte activation, and pre-existing reactivity. Preclinical immunogenicity risk was assessed holistically in vitro based on changes in innate activation risk, CD4 T cell risk, and B cell risk compared to corresponding native antibody. The results of this study suggest an overall moderate increase in immune activation potential for the antibody with isomerization, with only slight increases observed in oxidized and deamidated antibodies. These findings could lend understanding to the immunogenicity risk of chemical degradations in therapeutic antibodies and therefore inform optimization engineering at particular labile residues and risk assessment under the Quality by Design framework.