Regeneron developed 2 non-competing, anti-SARS-CoV-2 neutralizing monoclonal antibodies, casirivimab and imdevimab, as a therapeutic for COVID-19. Our bioanalytical teams navigated multiple hurdles to support development of this cocktail (REGEN-COV): multiple drug concentration and immunogenicity assays were developed, logistical issues were overcome throughout, and a non-standard immunogenicity package was used for the BLA submission. In this presentation, I will describe the clinical bioanalytical strategy and submissions for this important therapy.

Immunoassays are routinely used for anti-drug antibody (ADA) assessments in clinical studies, with a drive towards improvements in assay performance and bioanalytical laboratory productivity. Moreover, assay performance between sites or institutions can facilitate assay transfer during outsourcing. Here we present results for a pembrolizumab ADA bridging assay using Gyrolab microfluidic CD-based platform developed at two different companies with both assays showing high precision and drug tolerance, improving productivity and assay transfer. 

The role of critical quality attributes (CQAs) in inducing clinically relevant immune responses is largely unknown. Here, data will be presented that explores the potential impact of subvisible particles and silicone oil droplets in pre-filled syringes on inducing anti-drug antibodies and possible clinical relevance.

Therapeutic monoclonal antibodies in use in the clinic differ widely in their ability to elicit unwanted antidrug antibodies, and includes fairly immunogenic examples such as infliximab and adalimumab. Routine diagnostic testing service for PK and ADA has been available and is being used to variable degrees by clinicians to make informed treatment decisions for these drugs. Which role does immunogenicity of these therapeutic monoclonal antibodies play in clinical practice?

Complement can be a meaningful immunogenicity effector. I will discuss specific data that were required for a comprehensive understanding of Pegvaliase immunogenicity: characterization of both the maturation of the anti-therapeutic immune response (specificity and isotypes over time) as well as complement (circulating immune complex and complement levels). In addition, I’ll discuss how nonclinical assessments of complement activation by oligonucleotide therapeutic candidates can inform our clinical immunogenicity risk-assessment.

While all biotherapeutics have immunogenic potential, clinical outcomes such as safety and efficacy drive clinical development. Incorporating immunogenicity data into the clinical database will facilitates future analyses of potential impact on these outcomes. In November 2021, the Standardized Data Tabulation Model (SDTM) update to the Immunogenicity Specimens Assessments domain (IS) will provide structure to consistently capture immunogenicity data while maintaining flexibility to represent different tiered testing schemes. 

Reporting levels of antibodies in terms of titer is generally understood and accepted by regulatory and medical communities. A strong correlation between signal-to-negative control (S/NC) and titer has been observed across multiple Pfizer programs. Retrospective analysis of anti-bococizumab ADA response and correlation of impact on pharmacokinetic (PK) and pharmacodynamic (PD) endpoints illustrates S/NC is a valid alternative to titer for characterizing the magnitude and stratification of clinically relevant ADA response.

I will discuss the potential impact of pre-existing immunity on the efficacy of AAV-based gene therapy and provide a brief overview of mitigation strategies. Additionally, I will present preliminary non-clinical data from a few approaches we have evaluated aiming to remove existing antibodies or prevent the development of treatment-induced antibodies.

CAR T cell immunotherapy has become one of the most promising approaches for treatment of hematological malignancies. While both cellular and humoral immunogenicity of CAR T products could affect efficacy and may be monitored, most published assessments have so far failed to indicate direct clinical correlations with in vitro testing. This presentation will provide an overview of concepts, strategies, and methodologies for assessing cellular and humoral immunogenicity of CAR T cell therapies. 

Drug interference is a major challenge in clinical immunogenicity assessment, especially assaying for neutralizing antibodies (NAb), which could lead to erroneous results. Herein, we are excited to share our new approach to increase the drug tolerance of NAb assay while preserving the sensitive NAb species in serum. In addition, our new approach offers several advantages towards cost-effectiveness with minimal use of biotin-drug and unnecessity to use streptavidin-coated magnetic beads.

Cellular therapies where patient T cells are engineered to attack tumors have been shown to be an effective cancer treatment; however, persistence of the infused T cell product is critical for clinical efficacy. Depletion of the infused T cell product can occur through several mechanisms, but one critical pathway is through the host immune response. Therefore, it is critical to develop robust cellular immunogenicity assays to detect the patient immune reactivity.

Anti-drug antibody (ADA) assessment is a critical component of the safety and efficacy evaluation of protein therapeutics in the clinic since ADA can interfere with target engagement, eliminate the drug from the body and/or lead to serious adverse events. Serum samples are frequently treated with low pH solutions to dissociate the therapeutic from ADA prior to measurement. Such treatment may result in ADA denaturation and defeat the intended purpose. Using a domain antibody therapeutic and several ADA controls of varying affinities, we examine and report the differential impact of several acids/pH levels on assay drug tolerance and antibody sensitivity.