The broader clinical use of bispecific T cell engagers for inducing anti-tumour toxicity is hindered by their on-target off-tumour toxicity and the associated neurotoxicity and cytokine-release syndrome. Here we show that the off-tumour toxicity of a supramolecular bispecific T cell engager binding to the T cell co-receptor CD3 and to the human epidermal growth factor receptor 2 on breast tumour cells can be halted by disengaging the T cells from the tumour cells via the infusion of the small-molecule drug amantadine, which disassembles the supramolecular aggregate. Supramolecular chemistry may be further leveraged to control the anti-tumour activity and off-tumour toxicity of bispecific antibodies.

Bispecific engagers are off-the-shelf agents that recruit endogenous T and NK cells to eradicate tumor cells in a major histocompatibility complex (MHC)-independent manner. However, the promise of BiTE molecules in the treatment of solid tumors has been challenged by antigenic heterogeneity and the immunosuppressive tumor microenvironment (TME). We have developed bispecific engager-sialidase fusion proteins to address these challenges by targeted removal of aberrantly expressed sialoglycans in the TME.

We have developed a bispecific antibody-conjugate platform to enhance the multifunctional capabilities of antibodies. Several bispecific antibodies targeting CD20, HER2, and CD40 have been produced to enable a versatile antibody/drug conjugate tool via a simple mixing step. We have studied drug conjugates based on peptide and oligonucleotides-based cargoes using this technology and have investigated conjugate stability and its impact on in vitro and in vivo drug efficacy.

Cell engagers are often detuned to reduce the risk of toxicity. This strategy can sacrifice the magnitude of cytotoxicity and addresses neither cell fitness nor response durability. Simultaneous adjustment of cell engager synaptic distance and apparent affinity for targets allows for optimization of signal strength to establish a “cytokine window” at maximum cytotoxicity. Such engagers support the inclusion of functionally specific cytokines that promote proliferation, oppose functional exhaustion, and facilitate the targeting of small lymphocyte populations with inherent abilities to distinguish normal from diseased cells.

Major progress in the field of T cell redirecting therapies have contributed to the successful development of T cell engager (TCEs) and the recent approval of several molecules for haematological malignancies and solid tumours. However, this class of therapies is still associated with challenges limiting their widespread use, including risk of high-grade toxicity requiring specialized management, as well as potential long-term exhaustion of the T cell population. Autoregulation (AR) provides an embedded mechanism that enables the specific inactivation of TCEs when there is a risk of T cell overactivation to limit T cell stimulation and preserve function. This has led to the development of next generation of TCEs with an improved therapeutic index due to a safer, more efficacious profile.

This talk will explore the use of engineered allogeneic T cells in enhancing bispecific antibody (biAb) cancer immunotherapy. By decoupling T cell receptor (TCR) binding from CD3 signaling, we maintain biAb-driven T cell activation while preventing harmful alloreactive responses. In a CD19+ tumor model, these engineered T cells, combined with the biAb blinatumomab, demonstrated effective tumor clearance without detectable alloreactivity, highlighting a promising approach for ‘off-the-shelf’ T cell therapies.

Like camelids, sharks produce a heavy chain isotype, IgNAR. The variable domains of shark IgNAR, so called VNARs, are structurally more similar to TCR and Ig light chain variable regions than those of Ig heavy chains. The highly diverse structural repertoire created by the presence of 4 CDR/hypervariable loops allows VNARs to bind in unique ways and access epitopes unrecognized by conventional Igs or, for some targets, camelid VHHs. We will discuss how we are exploiting the novel binding modalities of VNARs obtained from immunized nurse sharks to generate bispecific and multispecific antibodies with extended binding profiles and improved function.

A subset of bovine antibodies displays a peculiarly long CDR-H3 which is composed of a stalk and a knob region. Importantly, the knob is primarily responsible for antigen binding. We have harnessed this specific diversity for the generation of mono- and multispecific antibody derivatives and also generated a novel symmetric bispecific antibody format by introducing the knob paratope into the CH3 domain of the Fc part of an IgG.

The principle of a bispecific antibody targeting CD3 to redirect cytotoxic T cells toward a tumor target has undeniably contributed to the success of T cell engagers and led to the recent approval of several molecules showing undisputed efficacy in both haematological malignancies and solid tumours. A broad range of research programs are now looking at ways to enhance the potential of these molecules and develop next-generation TCEs.

• New technologies to optimize the balance between efficacy and adverse events
• Harnessing multispecific antibody formats for enhanced efficacy/specificity
• Maximizing the efficiency of TCEs in the solid tumor microenvironment?

• Design parameters and objectives for T cell engagers
• Engineering strategies to improve their on-target (correct receptor) on-tissue (correct localization)
• Engineering strategies to reduce their on-target (correct receptors) off-tissue (wrong tissue localization)
• Considerations for the timing, reversibility, and translation of these approaches

Conventional T cell engagers (TCEs) for solid tumors face challenges of “on-target, off-tumor toxicity” and T cell dysfunction by CD3 activation alone. The newly developed SAIL66, a trispecific antibody targeting CLDN6/CD3/CD137, adopts a proprietary Dual-Ig to activate both of CD3 and CD137. Our CLDN6 specific Fab and the Dual-Ig platform with unique binding mode enabling superior T cell activation and potent anti-tumor effects to conventional TCEs.

This presentation discusses the pivotal role of dendritic-T cell crosstalk in driving anti-tumor immunity and enhancing immunotherapy. I will highlight our recent studies that led to the development of new immunotherapies, harnessing dendritic cell-T cell interactions for optimal efficacy.

CD3 bispecific T cell engagers redirect a patient's T cells to cancer cells and have emerged as a therapeutic strategy for the treatment of diverse cancers with 10 drug approvals, 9 approvals since 2022, including 2 approvals in solid tumors. Recent preclinical and clinical studies have identified strategies to utilize T cell costimulation to optimize T cell engager-induced anti-tumor immunity. EVOLVE integrates proprietary light-chain pairing, CD2 and CD3 affinity-tuned agonism to deliver potent tumor killing with balanced cytokine release in a highly developable platform.

The design of bispecific fusion proteins is a central challenge for the realization of new immunotherapeutic strategies. We developed a multi-scale computational framework to understand how bispecific fusion proteins target surface-bound membrane receptors. We found that proteins with long and flexible linkers are more efficient in targeting receptors.

The development of therapeutic molecules is often limited by insufficient on-target efficacy and adverse effects related to on-target, off-tissue activity. Ampersand has developed a computationally powered drug-discovery approach that has identified tissue-specific addresses that in turn has enabled the generation of a new type of programmable biologic. The resulting AND-Body Therapeutics are designed to specifically target the site of disease and conditionally actuate biology after localizing, thus sparing healthy tissue or cells. AND-Body molecules have a significantly improved therapeutic index when compared to non-targeted medicines, making them an attractive modality to address new targets for the treatment of a multitude of different diseases.

The majority of bispecific IgG molecules reported so far are asymmetric format that have monovalent binding on each epitope. We developed a novel bivalent bispecific antibody with a native IgG-like structure containing four Fabs that enhances binding avidity compared to traditional monovalent bispecific. This presentation will focus on the engineering, developability and applications of bivalent bispecifics in infectious diseases