Selection of a Ligand-Binding Neutralizing Antibody Assay for Benralizumab: Comparison with an Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) Cell-Based Assay

A competitive ligand binding assay for detection of neutralizing antibodies against an insulin analog

Biotherapeutics have the potential to trigger undesired immune responses in the patients. For therapeutic proteins, immunogenicity is manifested as anti-drug antibodies (ADA). Because ADA could compromise pharmacokinetics, efficacy, and safety, regulatory agencies require immunogenicity assessment during clinical development. A tiered bioanalytical approach is recommended to monitor clinical immunogenicity, and neutralizing antibodies (NAb) are studied in Tier 4 if the molecule is immunogenic. Although cell-based assays, which reflect the pharmacological mechanism of action, are in some cases the preferred assay format for detecting NAbs, they are associated with operational complexity and sometimes suboptimal assay performance. Alternatively, non-cell-based assays have also been developed and implemented. In our current study, a competitive ligand binding assay (CLBA) was developed to detect NAbs for insulin efsitora alfa (efsitora, basal insulin Fc, LY3209590), a novel fusion protein being studied for the treatment of Type 1 diabetes and Type 2 diabetes. The CLBA demonstrated acceptable sensitivity, drug tolerance, precision, and robustness, and thus provides a suitable approach for detecting NAbs against efsitora.

Neutralizing Antibody Validation Testing and Reporting Harmonization

Evolving immunogenicity assay performance expectations and a lack of harmonized neutralizing antibody validation testing and reporting tools have resulted in significant time spent by health authorities and sponsors on resolving filing queries. A team of experts within the American Association of Pharmaceutical Scientists' Therapeutic Product Immunogenicity Community across industry and the Food and Drug Administration addressed challenges unique to cell-based and non-cell-based neutralizing antibody assays. Harmonization of validation expectations and data reporting will facilitate filings to health authorities and are described in this manuscript. This team provides validation testing and reporting strategies and tools for the following assessments: (1) format selection; (2) cut point; (3) assay acceptance criteria; (4) control precision; (5) sensitivity including positive control selection and performance tracking; (6) negative control selection; (7) selectivity/specificity including matrix interference, hemolysis, lipemia, bilirubin, concomitant medications, and structurally similar analytes; (8) drug tolerance; (9) target tolerance; (10) sample stability; and (11) assay robustness.

A competitive ligand-binding assay for the detection of neutralizing antibodies against dostarlimab (TSR-042)

Dostarlimab is a humanized anti–PD-1 monoclonal antibody. Dostarlimab (JEMPERLI; TSR-042) was recently approved in the USA and in the EU. The presence of neutralizing antibodies (NAbs) is a cause for concern because they block the therapeutic function of the antibody and reduce drug efficacy. Therefore, programs developing therapeutic biologics need to develop and validate assays that adequately assess the presence of NAbs in the serum of patients treated with biologic therapies. Presented here is the development and validation of a competitive ligand-binding assay that specifically detects anti-dostarlimab NAbs in human serum. Precision, sensitivity, hook effect, selectivity, assay robustness, stabilities, and system suitability were evaluated. In addition, drug tolerance of the assay with the implementation of a drug removal process was investigated. The cut point factor for the detection of NAbs in human serum at a 1% false-positive rate was determined. The assay’s precision, sensitivity, hook effect, selectivity, robustness, and drug interference were tested and found to be acceptable. With system suitability and stability established, this assay has been used to evaluate NAbs to guide the development of dostarlimab.

Trial registration: Clinicaltrials.gov, NCT02715284. Registered 9 March 2016

2020 White Paper on Recent Issues in Bioanalysis: Vaccine Assay Validation, qPCR Assay Validation, QC for CAR-T Flow Cytometry, NAb Assay Harmonization and ELISpot Validation (Part 3 - Recommendations on Immunogenicity Assay Strategies, NAb Assays, Biosimilars and FDA/EMA Immunogenicity Guidance/Guideline, Gene & Cell Therapy and Vaccine Assays)

The 14^th edition of the Workshop on Recent Issues in Bioanalysis (14^th WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14^th WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by LCMS were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the Global Bioanalytical Community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations on Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity). Part 1 (Innovation in Small Molecules, Hybrid LBA/LCMS & Regulated Bioanalysis), Part 2A (BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation) and Part 2B (Regulatory Input) are published in volume 13 of Bioanalysis, issues 4 and 5 (2020), respectively.

Immunogenicity of Protein Therapeutics: A Lymph Node Perspective

The continuous development of molecular biology and protein engineering technologies enables the expansion of the breadth and complexity of protein therapeutics for in vivo administration. However, the immunogenicity and associated in vivo development of antibodies against therapeutics are a major restriction factor for their usage. The B cell follicular and particularly germinal center areas in secondary lymphoid organs are the anatomical sites where the development of antibody responses against pathogens and immunogens takes place. A growing body of data has revealed the importance of the orchestrated function of highly differentiated adaptive immunity cells, including follicular helper CD4 T cells and germinal center B cells, for the optimal generation of these antibody responses. Understanding the cellular and molecular mechanisms mediating the antibody responses against therapeutics could lead to novel strategies to reduce their immunogenicity and increase their efficacy.

Effectiveness of benralizumab for allergic and eosinophilic predominant asthma following negative initial results with omalizumab

A 64-year-old woman, who had presented with a 30-year history of refractory asthma, and been treated with anti-allergic drug therapy, inhaled corticosteroids, a long-acting beta-agonist, and a long-acting muscarinic antagonist. She had been characterized as an allergic, eosinophilic asthmatic. Although omalizumab was tried initially, it was found to be insufficient. We began treatment with benralizumab. The asthma symptom control and sinusitis were improved immediately. Benralizumab was effective for overlapping patient population following negative initial results with omalizumab.