A mechanistic marker-based screening tool to predict clinical immunogenicity of biologics.

BACKGROUND: The efficacy and safety of therapeutic proteins are undermined by immunogenicity driven by anti-drug antibodies. Immunogenicity risk assessment is critically necessary during drug development, but current methods lack predictive power and mechanistic insight into antigen uptake and processing leading to immune response. A key mechanistic step in T-cell-dependent immune responses is the migration of mature dendritic cells to T-cell areas of lymphoid compartments, and this phenomenon is most pronounced in the immune response toward subcutaneously delivered proteins. METHODS: The migratory potential of monocyte-derived dendritic cells is proposed to be a mechanistic marker for immunogenicity screening. Following exposure to therapeutic protein in vitro, dendritic cells are analyzed for changes in activation markers (CD40 and IL-12) in combination with levels of the chemokine receptor CXCR4 to represent migratory potential. Then a transwell assay captures the intensity of dendritic cell migration in the presence of a gradient of therapeutic protein and chemokine ligands. RESULTS: Here, we show that an increased ability of the therapeutic protein to induce dendritic cell migration along a gradient of chemokine CCL21 and CXCL12 predicts higher immunogenic potential. Expression of the chemokine receptor CXCR4 on human monocyte-derived dendritic cells, in combination with activation markers CD40 and IL-12, strongly correlates with clinical anti-drug antibody incidence. CONCLUSIONS: Mechanistic understanding of processes driving immunogenicity led to the development of a predictive tool for immunogenicity risk assessment of therapeutic proteins. These predictive markers could be adapted for immunogenicity screening of other biological modalities.

Protein drugs have a structure that is very similar to proteins in the human body, however there are slight differences. This can result in a person's immune system having a negative reaction to the drug. Unfortunately, during the early stages of drug development, it is currently difficult to predict which of these potential new drugs might cause this problem. We think that there is a higher chance for undesired immune responses to protein drugs when they cause an increase in the movement of the body's immune cells from the drug injection site to the lymph nodes. The more immune cells that arrive in the lymph node, the stronger the immune reaction. We developed a method that can predict how likely it is that a protein drug will trigger the unwanted activation and movement of these immune cells. This tool has the potential to improve our ability to predict, and thus avoid, unwanted immune system reactions toward protein drugs. This could shorten the time and cost required to develop new drugs.

Immunogenicity of Therapeutic Biological Modalities - Lessons from Hemophilia A Therapies.

The introduction and development of biologics such as therapeutic proteins, gene-, and cell-based therapy have revolutionized the scope of treatment for many diseases. However, a significant portion of the patients develop unwanted immune reactions against these novel biological modalities, referred to as immunogenicity, and no longer benefit from the treatments. In the current review, using Hemophilia A (HA) therapy as an example, we will discuss the immunogenicity issue of multiple biological modalities. Currently, the number of therapeutic modalities that are approved or recently explored to treat HA, a hereditary bleeding disorder, is increasing rapidly. These include, but are not limited to, recombinant factor VIII proteins, PEGylated FVIII, FVIII Fc fusion protein, bispecific monoclonal antibodies, gene replacement therapy, gene editing therapy, and cell-based therapy. They offer the patients a broader range of more advanced and effective treatment options, yet immunogenicity remains the most critical complication in the management of this disorder. Recent advances in strategies to manage and mitigate immunogenicity will also be reviewed.

Immunogenicity Challenges Associated with Subcutaneous Delivery of Therapeutic Proteins.

The subcutaneous route of administration has provided convenient and non-inferior delivery of therapeutic proteins compared to intravenous infusion, but there is potential for enhanced immunogenicity toward subcutaneously administered proteins in a subset of patients. Unwanted anti-drug antibody response toward proteins or monoclonal antibodies upon repeated administration is shown to impact the pharmacokinetics and efficacy of multiple biologics. Unique immunogenicity challenges of the subcutaneous route have been realized through various preclinical and clinical examples, although subcutaneous delivery has often demonstrated comparable immunogenicity to intravenous administration. Beyond route of administration as a treatment-related factor of immunogenicity, certain product-related risk factors are particularly relevant to subcutaneously administered proteins. This review attempts to provide an overview of the mechanism of immune response toward proteins administered subcutaneously (subcutaneous proteins) and comments on product-related risk factors related to protein structure and stability, dosage form, and aggregation. A two-wave mechanism of antigen presentation in the immune response toward subcutaneous proteins is described, and interaction with dynamic antigen-presenting cells possessing high antigen processing efficiency and migratory activity may drive immunogenicity. Mitigation strategies for immunogenicity are discussed, including those in general use clinically and those currently in development. Mechanistic insights along with consideration of risk factors involved inspire theoretical strategies to provide antigen-specific, long-lasting effects for maintaining the safety and efficacy of therapeutic proteins.