Our laboratory has constructed the V_HH and V_NAR single domain antibody phage display libraries from camels (Camelus dromedarius) and sharks (Ginglymostoma cirratum). In my talk, I will discuss (i) isolation of camel V_HHs and shark V_NARs against PD-L1 and B7-H3, (ii) characterization of CAR T cells derived from these single domain antibodies for treating solid tumors including pancreatic cancer, neuroblastoma and hepatocellular carcinoma, and (iii) mechanisms of action related to NFkB and NFAT signaling.

Bispecific anti-CD20, anti-CD19 CAR T cells are being explored as a potential second generation cell therapy treatment for B-cell non-Hodgkin lymphoma. Unique to our program is utilization of a point-of-care CAR T cell manufacturing process with the Prodigy CliniMACS device and exploration of a fresh (non-cryopreserved) infusion of CAR T cells. In this talk, we will review clinical outcomes of this vector, manufacturing platform, benefits of a fresh infusion, and future directions.

We generated a bispecific antibody that targets both the prostate tumor–specific antigen PSMA and CD3 (PMSAxCD3). Mice expressing the human extracellular regions of CD3 and human PSMA were generated to examine antitumor efficacy in the presence of an intact immune system and PSMA expression in normal tissues. Although PSMAxCD3 induced T cell activation and showed antitumor efficacy in mice with low tumor burden, PSMAxCD3 lost efficacy against larger solid tumors. 4-1BB costimulation boosted efficacy against larger tumors, leading to durable antitumor responses.

T cell engager (TCE) molecules that induce T cell-mediated lysis of cancer cells have demonstrated promising anti-solid tumor activity, but the factors that limit the response to these therapies in vivo remain poorly understood. Using immunocompetent mice and surrogate TCE molecules, we demonstrate that pre-treatment tumor T cell density is critical to TCE therapy efficacy, characterize the CD8+ T cell-polarized response to TCE therapy, reveal the dual role of CD4+ T cells in TCE efficacy, and identify therapeutic combinations that cause the regression of poorly T cell-infiltrated cold solid tumors refractory to immune checkpoint blockade therapy.

Mice expressing human immune checkpoints can serve as powerful preclinical models to evaluate the in vivo efficacy of anti-human antibody candidates for immuno-oncology targets. To ensure immunocompetence, knock-in humanized mouse models are carefully designed and subjected to rigorous validation. This session will highlight the use of humanized CD3E and CD3EDG models for broader targeting of the entire CD3 complex with novel mono- and bispecific antibody therapeutics.

TCR/BCR repertoire profiling holds great potential for understanding disease mechanisms. We introduce a novel technology for profiling of all human TCR and BCR variable regions and phenotypic characterization of immune cells in bulk and at the single-cell level in PBMCs and immune cell fractions. Preliminary data shows that TCR/BCR clonotype analysis combined with targeted expression profiling of immune cells can be applied for large-scale discovery in several immune-responsive model systems. 

We develop conditionally activated CARs to improve the safety profile of CAR T cells. The tumor antigen recognition is directly modulated by an FDA-approved small molecule drug. The resulting CAR T cells demonstrate specific cytotoxicity of tumor cells comparable to that of traditional CARs, but the cytotoxicity is reversibly attenuated by the addition of the small molecule.

Maverick has developed a novel recombinant bsAb platform called COBRA (Conditional Bispecific Redirected Activation). COBRAs are engineered to enable targeting of more widely expressed and validated tumor cell surface antigens by focusing T cell engagement within the tumor microenvironment. Maverick has (2) initial leads in clinical development, TAK-186 (EGFR-targeted COBRA) and TAK-280 (B7H3-targeted COBRA), which have the potential to treat a wide variety of tumor indications.  The data presented here will demonstrated the pre-clinical data package on both molecules, with a focus on TAK-280, which encompasses a unique targeting mechanism relative to our initial COBRA TAK-186.  

The humanized mice capable of evaluation of tumor microenvironment in vivo have provided a unique platform for immuno-oncology drug tests.  Genetically engineering mice and human immune system reconstituted mice show different features to facilitate drug evaluation, and model types related to efficacy and toxicity results.  We'll present the pre-clinical model choice based on drug design exemplified by Fc dependent antibody and T cell engager and showing toxicity evaluation data.

Preclinical studies demonstrated potency of anti-CD79b/CD3 TDB can be enhanced with increased binding affinity of either the anti-CD79b arm or the anti-CD3 arm. This evaluates the effect of CD3 binding affinities on PK and how it relates to the PD and safety. Anti-cynoCD79b/CD3 TDB was well tolerated, exhibited nonlinear PK consistent with target-mediated clearance (CL_Total range: 42-315 mL/day/kg) and resulted in dose-dependent B cell depletion.

We established in vivo imaging to visualize both antibody delivery and T cell migration and observed three phenotypes, (1) good accumulation of both antibodies and T cells, (2) good antibody delivery but suppressed T cell migration, and (3) suppression of T cells and antibodies. In solid tumors, (2) and (3) were predominant. Moreover, exhausted T cells lost proliferative and cytotoxic activities, which could attenuate bispecific antibody (BsAb) efficacy in vivo.  Hence, we are developing BsAb therapy in combination with immunoregulation using DDS and molecular imaging to overcome T cell deserts and exhaustion in the tumor microenvironment.

Glycoepitopes are potent targets for tumor therapeutics due to their unique tumor-specificity and broad indication coverage. We developed an IL-15-based immunocytokine (PM-IL15) targeting a conformational induced glycosylation/protein combined epitope (glycoepitope) on MUC1. PM-IL15 is designed to induce anti-tumor responses directly within the tumor microenvironment. It has high potential for the treatment of solid tumors either as monotherapeutic agent or as valuable combination partner for different anti-cancer drugs.

IgG mAbs eliminate tumor cells through NK cell-mediated ADCC and macrophage-mediated antibody-dependent phagocytosis. IgG, however, ineffectively recruits neutrophils as effector cells. By contrast, IgA mAbs induce neutrophil migration and activation through the IgA Fc receptor (FcaRI), but do not activate NK cells and have poorer half-life. We combined the agonistic activity of IgG mAbs and FcaRI targeting in a bispecific antibody, and results with this novel molecule will be discussed.

Bispecific antibodies have the potential to provide new options in indications where checkpoint inhibitors fail. T cell redirecting CD3 antibodies have paved the way for this class of immunotherapies. A new promising class of tumor associated antigen (TAA) conditionally active agonistic bispecific antibodies that modulates checkpoint co-stimulators, e.g., CD40 and 4-1BB, has recently emerged as a promising approach to enhance T cell priming and activity in immuno-oncology. Alligator develops bispecific antibodies targeting both TAA x CD40/TAA x 4-1BB and data from these programs will be presented.

Receptor-mediated internalization is an essential part of MOA for antibody drug conjugates (ADC). A bispecific format of ADC may affect its internalization properties. Contrary to parental arm antibodies a biparatopic anti-HER2 antibody (anti-HER2-Bs), targeting two non-overlapping epitopes on HER2, induced rapid internalization and efficient degradation of receptors. Our study investigated the molecular mechanism of rapid internalization and redirected trafficking providing insights in drug MOA and rational design of bispecific molecules.

On the basis of technology developed at City of Hope, we have developed CD38-CD3 Biologics Nested Inside Chains (BIONICS), which comprise a CD38 nanobody linked to an anti-CD3 antibody via a short peptide linker. Our data show that CD38-CD3 BIONICS induces remarkable T cell activation and can eradicate acute myelogenous leukemia (AML) cells not only in vitro but also ex-vivo in autologous patient setting and in vivo animal models.