1. Biological activity validation of a computationally designed Rituximab/CD3 T cell engager targeting CD20+ cancers with multiple mechanisms of action
- Author
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Sachith Gallolu Kankanamalage, Cai Huang, Yue Liu, Jiadong Shi, Jing Zhang, Zhejun Jia, Jianbo Dong, Joe Zhou, Bo Wang, Allison Titong, Steven Z. Kan, Jun Lin, Shuhua Han, and Wenyan Cai
- Subjects
T cell ,Immunology ,therapeutic antibodies ,computer-aided antibody design ,Immunology and Allergy ,Medicine ,Original Research Article ,CD20/CD3 ,Antibody-dependent cell-mediated cytotoxicity ,CD20 ,AcademicSubjects/SCI01030 ,biology ,business.industry ,medicine.anatomical_structure ,Cell killing ,T cell engager antibodies ,Cancer cell ,Cancer research ,biology.protein ,Cytokine secretion ,Rituximab ,AcademicSubjects/SCI00100 ,Antibody ,bispecific antibodies ,business ,medicine.drug - Abstract
Background Bispecific T cell engaging antibodies (TEAs) with one arm targeting a cancer antigen and another arm binding to CD3 have demonstrated impressive efficacy in multiple clinical studies. However, establishing a safety/efficacy balance remains challenging. For instance, some TEAs have severe safety issues. Additionally, not all patients or all cancer cells of one patient respond equally to TEAs. Methods Here, we developed a next-generation bispecific TEA with better safety/efficacy balance and expanded mechanisms of action. Using the computer-aided antibody design strategy, we replaced heavy chain complementarity-determining regions (HCDRs) in one Rituximab arm with HCDRs from a CD3 antibody and generated a novel CD20/CD3 bispecific antibody. Results After series of computer-aided sequence optimization, the lead molecule, GB261, showed great safety/efficacy balance both in vitro and in animal studies. GB261 exhibited high affinity to CD20 and ultra-low affinity to CD3. It showed comparable T cell activation and reduced cytokine secretion compared with a benchmark antibody (BM). ADCC and CDC caused by GB261 only killed CD20+ cells but not CD3+ cells. It exhibited better RRCL cell killing than the BM in a PBMC-engrafted, therapeutic treatment mouse model and good safety in cynomolgus monkeys. Conclusions Thus, GB261 is a promising novel TEA against CD20+ cancers.
- Published
- 2021