Innovative strategies for T cell engagers for cancer immunotherapy

T cell engagers (TCEs) are a promising class of cancer immunotherapy that re-direct T cells to kill tumor cells. However, their clinical application is limited by several challenges, including cytokine release syndrome (CRS), on-target off-tumor toxicity and overcoming immunosuppression in both hematological and solid tumors. This review explores recent innovations in TCE design aimed at improving their safety and efficacy. Key developments include optimizing geometry to facilitate effective immune synapses, affinity optimization of the anti-CD3/TCR domain and targeting of specific T cell subsets which both aim to reduce CRS. Logic-gated approaches such as dual-targeted and conditional TCEs activated by tumor microenvironment factors have the potential to reduce on target, off tumor toxicity and potentially increase the depth and durability of response. Additionally, leveraging costimulatory signaling offers the potential to further improve efficacy across hematological and solid tumor settings. The next generation of TCEs is expected to overcome some of the limitations of conventional TCEs, enhancing their therapeutic window and enabling combination therapies. As the field advances, TCEs are poised to become a cornerstone of cancer immunotherapy, potentially improving outcomes for a broader range of patients than the ones currently benefiting from conventional immunotherapy.