Bispecific ADCs—bridging HER2, and high turnover surface protein, PRLR—travel to lysosomes and improve efficacy of HER2 ADCs with non-cleavable linker. Here we present an extended version of this approach to improve ADC therapeutic index, which may be applicable to the broad set of ADC targets.

Effective design of IgG-like multi-specific ADCs necessitates a thorough evaluation of multiple parameters. This includes optimizing the affinity and potency of targeting arms, maximizing payload delivery through diverse epitope combinations and binding geometries, and understanding the influence of antigen density variations on efficacy. By employing an easy-to-use bispecific platform that supports a diverse array of variable domains without custom engineering and is compatible with one-step affinity purification, extensive empirical testing of numerous bispecific combinations in their final format is enabled. This presentation will explore how such a platform can simplify, accelerate, and de-risk the development of bispecific ADCs.

Inter-patient and intra-tumoral target heterogeneity is a challenge for antibody drug conjugates (ADCs). A novel-format bispecific ADC targeting two different TAAs independently could increase the addressable patient population relative to a monospecific ADC or a bivalent bispecific ADC. A library of 48 bispecific molecules was designed, employing multiple paratopes and variable antibody formats with the aim of targeting tumors that express either FRα, NaPi2b, or both targets.

Understanding molecular recognition mechanisms is crucial to development of platforms to intervene with the immune system. By using protein design methods, we have developed a novel protein strategy to achieve antigen-specific binding to class I, II, and non-classical Major Histocompatibility Complexes (MHC). The platform, called TRACeR, breaks from classical T cell receptor (TCR)-restricted modalities and offers unprecedented simplicity and speed to develop MHC-antigen specific binders. We believe that the ease of deployment and specificities that this platform offers can be of broad interest for general MHC-targeting applications.

HIV-1 persists in a latent reservoir of resting memory CD4+T cells.  "Shock and kill" approaches to induce HIV-1 gene expression, protein production, and targeting by the host immune system have been unsuccessful.  Using phage display technology, we constructed T cell receptor (TCR)-mimic antibodies to HIV peptide-MHC (pMHC) derived from Gag and Pol proteins that were identified via LC-DIA mass spectrometry from cells infected with a pseudotyped HIV reporter virus (NL4.3 dEnv).  These bispecific antibodies induced killing of CD4+T cells infected with reporter strains as well as patient isolates of HIV-1, which has significant implications for the HIV-1 cure field.

The talk will present learnings for understanding paratope-epitope interactions from computational analysis of > 850,000 atom-atom contacts from >1800 structurally elucidated antibody-antigen complexes and >11000 functional antibodies. The use of the learnings and patterns for antibody engineering and technologies for the generating of novel in-silico designed humanized single-domain antibody phage display libraries with maximal functional diversity for generating fusion partners. A novel technology for deep mining of antibody phage-display selections using ONT and dual UMI will be shown.

The inability of antibodies to penetrate the blood-brain barrier is a key limitation to their use in diverse applications. We are developing bispecific antibodies that engage CD98hc and efficiently transport IgGs into the CNS. Notably, CD98hc shuttles lead to much longer-lived brain retention than transferrin receptor shuttles while enabling more specific targeting due to limited CD98hc engagement in the brain parenchyma, which we demonstrate for several shuttled IgGs.

New approaches are needed to universally improve patient outcomes with CAR and TCR T cell therapies. We used IL-15 and IL-21 to enhance the efficacy of adoptive T cells. Self-delivery of these cytokines by CAR or TCR T cells prevents functional exhaustion by repeated stimulation and limits the emergence of dysfunctional natural killer (NK)-like T cells. Across different preclinical murine solid tumor models, we observed enhanced regression with each individual cytokine but the greatest anti-tumor efficacy when T cells were armored with both. The co-expression of membrane-tethered IL-15 and IL-21 represents a technology that could be applicable to multiple therapy platforms and diseases.

The Dual-Ig consist of a Fab which binds to both CD3 and CD137 in a competitive manner. It can be easily converted into a T cell bispecific antibody by attaching to a tumor antigen targeting Fab. This unique binding mode enhanced tumor target specific T cell activation and eliminated target independent T cell activation, which showed improved efficacy and safety profile. Different antibody formats generated from Dual-Ig platform and their efficacy in preclinical models will be shared in this presentation.

Vγ9Vδ2-T cells constitute a relatively homogeneous population of pro-inflammatory immune effector cells. This presentation will focus on the preclinical and early clinical development of bispecific Vγ9Vδ2-T cell engagers as a novel approach for cancer immunotherapy.

Although combination antiretroviral therapy (cART) is effective in suppressing HIV replication, it does not eliminate the population of T-cells that harbor integrated full-length replication competent proviral DNA (the HIV latent reservoir), and thus requires life-long adherence. A therapeutic agent capable of recognizing the HIV envelope glycoprotein expressed on latently infected T-cells following provirus activation, and safely recruiting the immune system to kill and eliminate these cells, is potentially capable of contributing to a functional cure for HIV. Here we describe the engineering and pre-clinical assessment of GS-8588, a bispecific T-cell engager targeting the HIV envelope glycoprotein that is currently in phase I clinical trials. The talk will cover engineering of all three component building blocks (anti-CD3, anti-gp120, hetero-Fc) as well as the bispecific format, with a focus on multi-dimensional optimization of both function and drug-like properties. In vitro pharmacology and in vivo NHP PK and toxicology data supporting the clinical studies of GS-8588 will also be shared.

Cancer cells require high levels of iron for rapid proliferation, leading to a significant upregulation of the iron carrier protein Transferrin Receptor (TfR) on their cell surface. Leveraging this phenomenon and the exceptionally fast endocytosis rate of TfR, we introduce Transferrin Receptor TArgeting Chimeras (TransTAC), a novel molecular archetype for membrane protein degradation in cancers and other cell types.

Targeted protein degradation (TPD) of plasma membrane proteins has emerged as a novel therapeutic avenue in drug development. While recent strategies have been successful, these approaches are still limited by the availability and modularity of suitable binders to generate heterobifunctional molecules. Here, we developed a TPD toolbox termed REULR (Receptor-Elimination-by-E3-Ubiquitin-Ligase-Recruitment):

• modular, “mix-and-match” strategy
  
• nanobody-based
  
• human and mouse cross-reactive 
  
• targeting 5 PA-TM-RING type E3-ligases (RNF128, RNF130, RNF167, RNF43, and ZNRF3)

A versatile targeting strategy by retasking five PA-TM-RING E3 to generate homo-, heterobifunctional, and arrayed multimeric REULRs to modulate cell surface receptors by induced proximity, allowing selective, tissue-specific applications.

We are interested in developing new strategies for targeted protein degradation, specifically on the cell surface. In this presentation, we will highlight the current state-of-the-art technology for targeted protein degradation on the cell surface, delve into the intricate mechanism of employing ligases on the cell surface for receptor degradation, and explore both the advantages and limitations of this technology.