Presentation will focus on challenges associated with assessing and predicting clinical immunogenicity of antibody-drug conjugates (ADCs). ADCs are complex therapeutic modalities, with several bioanalytical species in systemic circulation which complicates in vitro in vivo correlation of immunogenicity data and its interpretation. Speaker will provide insight on this challenging topic with some case studies.

Immunogenicity of biotherapeutics presents a major challenge during the clinical development of new protein drugs, including monoclonal antibodies. To address this, multiple humanization and de-immunization techniques that employ in silico algorithms and in vitro test systems have been implemented in the field. To date, no systematic study to examine the effectiveness of these approaches in the reduction of immunogenicity has been performed in vivo in humans or in a relevant animal model, such as non-human primates. Aside from retrospective analyses, there is very little direct information on the true predictability of in silico/in vitro approaches to predict immunogenicity observed in vivo. Since human and cynomolgus macaque are highly homologous and share similar mechanisms of antigen processing and presentation, it can serve as a useful model to study immunogenicity of biotherapeutics. Here, we examined an in silico-guided approach to reduce the risk of immunogenicity of two commercially available antibodies using cynomolgus macaque as a surrogate for human. The resultant engineered antibodies had a comparable affinity for TNFa, demonstrated similar biophysical properties, and exhibited significantly reduced ADA levels in cynomolgus macaque as compared to the parental antibodies, with a corresponding improvement in pharmacokinetic profile. The results point to the significant value in the investment in these engineering strategies and the relevance of testing in non-human primates as an important guide for monoclonal antibody optimization, which can contribute to improved clinical outcomes. 

Immunogenicity is one of the most complex issues to address in drug design and development and requires intelligent application of integrated platforms to mitigate the risk to your biologic. In this talk I will present case studies to illustrate the range of solutions that ProImmune provides including DC-T/T cell proliferation assays for lead selection/optimization, MAPPS assays for characterization of antigen presentation; HLA-peptide binding assays to characterize individual epitopes & undiluted whole blood cytokine storm assays.

Mass spectrometry profiling of peptides associated to human leukocyte antigen (HLA) – referred herein as immunopeptidomics – has become a dynamic new frontier in immunology, vaccine, and immunotherapy. In this presentation, we will describe the latest advances in the field. In particular, we will describe the importance of dissecting the molecular architecture that shapes the global composition of the immunopeptidome to understand and control tumor immunogenicity.

Next-generation sequencing (NGS) of paired-antibody heavy and light chains has opened up new possibilities for studying human antibody repertoires. Here, we applied high-throughput interrogation of human antibody responses and paired these data with large-scale T cell epitope prediction. We reveal new trends in antibody development that reduce antibody immunogenicity. These findings have broad implications for the identification and discovery of new antibody therapeutics with reduced immune rejection.

A key consideration for successful immunotherapy of cancers, autoimmunity and chronic infectious disease is the selective and specific modulation of the immune repertoire while avoiding systemic immune modulation and related safety liabilities. To that end, we have developed a unique biologics platform termed Immuno-STAT that provides the opportunity to directly target and modulate the antigen-specific T cell repertoire in the patient. 

Regulatory T (T_REG) cells hold promise for modulation of Th1-driven processes, including autoimmune and neurodegenerative disease, transplantation complications (graft rejection, GVHD), and foreign protein immunogenicity. Because T_REG and Th2-type cells counter-regulate Th1 responses, we developed an ex vivo manufacturing process that generates a T cell product of hybrid T_REG/Th2 phenotype. A phase I clinical trial of hybrid T_REG/Th2 cells has been developed for therapy of amyotrophic lateral sclerosis (clinicaltrials.gov; NCT04220190).   

Unwanted immune responses to therapeutic proteins can adversely affect clinical outcomes and may complicate product development. Reducing the risk of immunogenicity through application of ‘predictive’ assays during molecular design is appealing, though useful prediction via a single assay is not currently possible. I will describe an approach to integrate data relating to molecules and patients to simulate the outcome of clinical trials, including the introduction of an Immunogenicity Simulator consortium.

Risk assessment of protein drugs is most often performed using MHC-Associated Peptide Proteomics (MAPPs) and/or T cell activation assays. In this talk, we demonstrate how in silico methods trained on MS HLA eluted ligand data can effectively and accurately complement these assays for the risk assessment of protein drugs.

Treatment of patients with biotherapeutic protein products may result in immune responses of varying clinical relevance, including development of life-threatening anti-drug antibodies (ADA) that can limit product efficacy or impact its safety. Therefore, predicting the risk for immunogenicity of biotherapeutic products at early stages is a crucial need. This presentation will focus on in vitro T cell assay studies to characterize the immunogenic potential of different biotherapeutic proteins and their correlation to the clinically observed outcome.

The efficacy and mechanisms of action of negatively charged, antigen-encapsulating, carboxylated poly(lactide-co-glycolide) (PLG) nanoparticles (Ag-PLG) for gliadin tolerance induction in a Phase 2 clinical trial in celiac disease patients will be discussed. In addition, data showing the efficacy of Ag-PLG tolerance in inducing tolerance in a preclinical model of gene therapy using AAV-expressing green fluorescent protein will be presented and prospects for clinical translation for gene therapy will be discussed.