Harnessing the immune system has revolutionized cancer treatments, but toxicities limit the potential. Revitope develops T cell engagers (TwoGATE) designed to elicit a potent tumor-focused immune response. The split anti-CD3 paratope requires two antigens on the same tumor cell for activity, which may enable greater tumor specificity and drive potent in vitro and in vivo tumor cell killing. TwoGATE are well-tolerated in non-human primates and have excellent developability properties.

Many novel immune-oncology biologics are limited in clinical utility due to a narrow therapeutic window. The PROTECT (PROgrammed Tumor Engagement & Checkpoint/Costimulation Targeting) platform is designed to employ orthogonal mechanistic features in a multispecific design to increase the therapeutic window. In particular, we bring TME-specific activity and localized immune modulation in a single transferable, conditionally active design. We show that the PROTECT design is more active than treatment with combinations.

T cell engagers are widely recognized for their tremendous potential for cancer therapies, but with hundreds in development, only two are on the market. Limited pools of parental antibodies and limited access to bispecific engineering technologies have been barriers to bringing T cell engagers to the clinic. We combine  a diverse panel of fully human CD3-binding antibodies with our clinically-validated bispecific engineering platform to streamline discovery of T cell engager therapies.

T cell engagers are a potent therapeutic modality but often require careful management of cytokine release syndrome and other on-target toxicities. Here, we discuss our approaches to engineering protease-activated T cell engager prodrugs, present preclinical evidence on how these different approaches help improve the safety of T cell engagers and propose their utility in diseases previously intractable to T cell engagers.

XPATs are conditionally active T cell engagers (TCEs) designed to exploit the dysregulated protease activity in tumors. In preclinical studies across multiple tumor targets XPATs demonstrated 1) Strong masking of in vitro cytotoxicity by up to  4 logs;  2) Potent in vivo efficacy at doses similar to the efficacious doses of unmasked TCEs; 3) Masking increases tolerated Cmax in NHP by greater than 400-fold for HER2-XPAT.

We have selected antibody fragments by phage display that target mutant peptides derived from the tumour suppressor gene, p53R175H, and from oncogenes KRASG12V and IDH2R140Q. While it remains to be determined which class of therapeutics will prove more efficacious in humans, we present here two avenues, off-the-shelf bispecifics, and CAR T cell, to treat cancer harboring intracellular targets.

Antibody-based immunotherapy is a promising strategy for targeting tumor cells. However, classical antibody-based approaches are restricted to targeting cell-surface antigens. We engineered a novel T cell bispecific (TCB) antibody, containing a bivalent T cell receptor-like binding domain that recognizes the intracellular tumor antigen Wilms' tumor 1 (WT1) via pHLA. WT1-TCB facilitates potent in vitro, ex vivo and in vivo killing of AML cell lines and primary AML cells.

Proteolysis targeting chimeras (PROTACs) are essential bifunctional small molecules that engage the formation of a ternary complex consisting of an E3-ubiquitin-ligase, a target protein of interest and the PROTAC itself. Using switchSENSE technology and the novel DNA Y-structure, an E3-ligase and a target protein can be functionalized on separate ends of two FRET pair color-coded Y-arms, thereby performing high-throughput PROTAC screening to gain information on binary and ternary binding.

This talk will describe the BiXAb platform for the generation of bivalent, bispecific antibodies. The advantages of targeting non-conventional T cells and redirecting non-conventional T cells with BiXAb therapeutics will be outlined.

Human monoclonal antibody (mAb) therapeutics have demonstrated utility against emerging viruses but are often deployed as cocktails to enhance efficacy and reduce the risks of viral mutational escape. Here, I discuss our recent work to identify combinations of mAbs that recognize distinct epitopes and drive synergistic viral neutralization through multiple mechanisms. I show that combining such mAbs into bispecific antibodies affords enhanced antiviral potency in vitro and in vivo.

We developed CoV-X2, a fully human, IgG-like bispecific antibody rationally engineered to bind simultaneously to two sites on the SARS-CoV-2 Spike (Nature, 2021); it potently neutralizes all variants of concern, protects from the virus both prophylactically and therapeutically, and prevents formation of viral escape mutants in vivo. Bispecifics against Zika (Cell 2017) and Prion also had synergistic properties beyond those of the parental monoclonals. Simultaneous targeting of non-overlapping epitopes by IgG-like bispecific antibodies is feasible and effective against infectious diseases, combining the advantages of antibody cocktails with those of single-molecule approaches.

HIV-1 Env x CD3 DART molecules, which induce redirected T cell killing of HIV-1 Env-expressing cells, are being developed as clearance agents for use in strategies to reduce or eliminate persistent viral reservoirs in persons with HIV-1 (PWH) maintained on anti-retroviral therapy (ART). In vitro and in vivo properties of DART molecules with different anti-Env specificities and results from a first-in-human safety study in PWH on ART will be shared.

Bispecifics are exciting due to their improved specificity, additional MOA, and/or improved therapeutic index. They may be more risky due to increased development complexity, experiment combinatorics, cost and time. Here a T-Cell engager case study is used to highlight Applied BioMath Assess, a web enabled model informed drug development and discovery analysis application, that helps quickly generate actionable hypotheses, impacting critical thinking and portfolio decisions, thus derisking projects.

Bispecific antibodies offer potential advantages as therapeutics against infectious pathogens, including resistance to antigen mutations and the possibility of novel interactions due to the covalent linkage between component antibodies. Here, we discuss two studies: 1) the discovery of naturally occurring bispecific antibodies targeting malaria antigens and 2) the engineering of bispecific antibodies that potently neutralize SARS-CoV-2 variants of concern.

Synthetic Nucleic Acid (DNA) is a novel approach for developing immunotherapies in both the area of infectious disease as well as cancer. Next-generation in vivo self-assembling designs support biologic generation of designer mAbs as well as more complex Bispecific molecules. We will provide examples of this approach for infectious diseases, such as AMR and for the treatment of pathogenic cells.