Abstract Background: Currently approved monospecific antibody checkpoint inhibitors are often insufficiently effective for all patients and/or indications. Thus, investigators are interested in targeting multiple signaling pathways and/or cell types to enhance clinical outcomes, often in the form of multispecific antibody treatments (‘multispecifics’). Many of these multispecifics target the T cell as T cell engagers (TCEs), with the majority targeting CD3 and a tumor-associated antigen (TAA) to activate T cell-dependent cellular cytotoxicity. Co-stimulation by targeting CD28 or CD137 in addition to CD3 has recently shown promise. However, the large number of possible topologies and added complexity for manufacturing necessitate the development and application of a robust set of complementary technologies that facilitate generation and allow for functional screening of large multispecific panels. Methods: Co-stimulatory antibodies against CD28 were identified from synthetic IgG (kappa 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr C001.
Ross Connor (Wed,) studied this question.