Abstract Purpose: This abstract showcases how Absolute Antibody (a Vector Laboratories company) generate bi-specific antibodies based on existing monoclonal antibody therapeutics molecules, compare the constructs and feasibility in order to produce “well-behaved multi-specifics”. Experimental Procedures: Our recombinant platform converts any antibody into customizable multispecific formats with defined Fc mutations, enabling precise control of effector function. Using trastuzumab and a humanized OKT3 variant as binding arms, we generated and expressed a panel of bispecific constructs, purified them to high quality, and compared their expression profiles, monomer content, and binding. These variants now serve as a reference set for ongoing functional and biophysical characterization studies. Conclusions: Recent reports list 79 multi-specific antibodies in the clinic, while Absolute Antibody (a Vector Laboratories company) has produced more than 180 engineered formats. In this study, we built and analyzed 17 bispecific designs, revealing that Fc-containing architectures, scFv placement, and interface engineering strongly affect expression and stability. This reference panel highlights how design choices shape bispecific performance and is available for collaborative research. Citation Format: Catherine Bladen, Abbie Hardisty, Emily Blackwood, Holly Guz, Stacey Walker, Stephen Anderson, Michael Fiebig, Bowu Luan. Comparing potential bispecific formats comprising of trastuzumab and a humanized OKT3 abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4409.
Bladen et al. (Fri,) studied this question.