Characterization of a single reporter-gene potency assay for T-cell-dependent bispecific molecules. Issue 7 (3rd October 2019)

• Record Type: Journal Article
• Authors: Lee, Ho Young; Register, Ames; Shim, Jeongsup; Contreras, Edward; Wu, Qiang; Jiang, Guoying
• Is Part Of: MAbs. Volume 11:Issue 7(2019)
• Page Start: 1245
• Page End: 1253
• Publication Date: 2019-10-03
• Subjects: T-cell-dependent bispecific antibodies (TDBs) -- T cell activation -- mechanism of action (MoA) -- reporter gene potency assay -- bispecific antibodies (BsAbs) -- biological characterization strategy; Monoclonal antibodies -- Therapeutic use -- Periodicals; Monoclonal antibodies -- Periodicals; Antibodies, Monoclonal -- Periodicals; 616.0798
• DOI: 10.1080/19420862.2019.1640548
• Languages: English
• ISSNs: 1942-0862

Abstract

ABSTRACT: T-cell-dependent bispecific antibodies (TDBs) are promising cancer immunotherapies that recruit patients' T cells to kill cancer cells. There are many TDBs in clinical trials, demonstrating their widely recognized therapeutic potential. However, their complex, multi-step mechanism of action (MoA), which includes bispecific antigen binding, T-cell activation, and target-cell killing, presents unique challenges for biological characterization and potency assay selection. Here, we describe the development of a single reporter-gene potency assay for a TDB (TDB1) that is MoA reflective and sensitive to binding of both antigens. Our reporter-gene assay measures T-cell activation using Jurkat cells engineered to express luciferase under the control of an NFkB response element. The potencies of select samples were measured both by this assay and by a flow-cytometry-based cell-killing assay using human lymphocytes as effector cells. Correlating the two sets of potency results clearly establishes our reporter-gene assay as MoA reflective. Furthermore, correlating potencies for the same panel of samples against binding data measured by binding assays for each individual arm demonstrates that the reporter-gene potency assay reflects dual-antigen binding and can detect changes in affinity for either arm. This work demonstrates that one reporter-gene assay can be used to measure the potency of TDB1 while capturing key aspects of its MoA, thus serving as a useful case study of selection and justification of reporter-gene potency assays for TDBs. Furthermore, our strategy of correlating reporter-gene potency, target-cell killing, and antigen binding for each individual arm serves as a useful example of a thorough, holistic approach to biological characterization for TDBs that can be applied to other bispecific molecules.