Project description:CD3-bispecific antibodies represent an important therapeutic strategy in oncology. These molecules work by redirecting cytotoxic T cells to antigen-bearing tumor cells. Although CD3-bispecific antibodies have been developed for several clinical indications, cases of cancer-derived resistance are an emerging limitation to the more generalized application of these molecules. Here, we devised whole-genome CRISPR screens to identify cancer resistance mechanisms to CD3-bispecific antibodies across multiple targets and cancer types. By validating the screen hits, we found that deficiency in IFNγ signaling has a prominent role in cancer resistance. Interestingly, IFNγ functions by stimulating the expression of T cell killing-related molecules in a cell type-specific manner. Additionally, by assessing resistance to the clinical CD3-bispecific antibody flotetuzumab, we identified core fucosylation as a novel and critical pathway to regulate flotetuzumab binding to the CD123 antigen. Disruption of this pathway resulted in significant resistance to flotetuzumab treatment. Moreover, proper fucosylation of CD123 is required for its normal biological functions. In order to treat the resistance associated with fucosylation loss, flotetuzumab in combination with an alternative targeting CD3-bispecific antibody demonstrated superior efficacy. Together, our study reveals multiple mechanisms that can be targeted to enhance the clinical potential of current and future T cell engaging CD3-bispecific antibody therapies.
Project description:This is a phase II Randomized comparison clinical trial of activated CIK armed with anti-CD3-MUC1 bispecific antibody for advanced colorectal cancer. And the aim of this research is to study the clinical efficacy and safety of activated CIK armed with anti-CD3-MUC1 bispecific antibody for colorectal cancer.
Project description:We performed a global gene expression analysis comparing intragraft tolerant CD8+ T cells from CD3 antibody-treated mice showing permanent islet graft survival to intra-graft effector CD8+ T cells isolated from untreated mice showing acute rejection of islet allografts. The objective was to emphasize the anergic profile of CD8+ T cells residing within the pancreatic islet allograft of mice rendered tolerant following CD3 antibody therapy.
Project description:Purpose: Accumulating analyses of pro-oncogenic molecular mechanisms triggered a rapid development of targeted cancer therapies. Although many of these treatments produce impressive initial responses, eventual resistance onset is practically unavoidable. One of the main approaches for preventing this refractory condition relies on the implementation of combination therapies. This includes dual-specificity reagents that affect both of their targets with a high level of selectivity. Unfortunately, selection of target combinations for these treatments is often confounded by limitations in our understanding of tumor biology. Here, we describe and validate a multipronged unbiased strategy for predicting optimal co-targets for bispecific therapeutics. Experimental design: Our strategy integrates ex-vivo genome-wide loss of function screening, BioID interactome profiling and gene expression analysis of patient data to identify the best fit co-targets. Final validation of selected target combinations is done in tumorsphere cultures and xenograft models. Results: Integration of our experimental approaches unambiguously pointed towards EGFR and EPHA2 tyrosine kinase receptors as molecules of choice for co-targeting in multiple tumor types. Following this lead, we generated a human bispecific anti-EGFR/EPHA2 antibody that, as predicted, very effectively suppresses tumor growth, compared to its prototype anti-EGFR therapeutic antibody, cetuximab. Conclusion: Our work not only presents a new bispecific antibody with a high potential for being developed into clinically-relevant biologics, but more importantly, successfully validates a novel unbiased strategy for selecting biologically optimal target combinations. This is of a significant translational relevance, as such multifaceted unbiased approaches are likely to augment the development of effective combination therapies for cancer treatment.
Project description:T-cell-recruiting bispecific antibody therapy has yielded promising results in patients with hematologic malignancies, however, resistance and subsequent relapse remains a major challenge. T-cell exhaustion induced by persistent antigen stimulation or tonic receptor signaling has been reported to compromise outcomes of T-cell based immunotherapies. The impact of continuous exposure to bispecifics on T-cell function, however, remains poorly understood. In relapsed/refractory B-cell precursor acute lymphoblastic leukemia patients, 28-day continuous infusion with the CD19xCD3 bispecific antibody blinatumomab led to declining T-cell function. In an in vitro model system, mimicking 28-day continuous infusion with the half-life-extended CD19xCD3 bispecific AMG 562, we identified hallmark features of exhaustion arising over time. Continuous AMG 562 exposure induced progressive loss of T-cell function (day 7 vs day 28 mean specific lysis: 88.4% vs 8.6%; n = 6; p = .0003). Treatment-free intervals (TFIs), achieved by AMG 562 withdrawal, were identified as powerful strategy for counteracting exhaustion. TFIs induced strong functional reinvigoration of T cells (continuous vs TFI specific lysis on day 14: 34.9% vs 93.4%; ± SEM; n = 6; p < .0001) and transcriptional reprogramming. Furthermore, use of a TFI led to improved T-cell expansion and tumor control in vivo. Our data demonstrate the relevance of T-cell exhaustion in bispecific antibody therapy and highlight that T cells can be functionally and transcriptionally rejuvenated with TFIs. In view of the growing number of bispecific molecules being evaluated in clinical trials, our findings emphasize the need to consider and evaluate TFIs in application schedules to improve clinical outcomes.
Project description:Tumor-specific cytotoxic T cells are required for effective immunotherapy. Here we introduce a bispecific fusion protein (tebentafusp) designed to target gp100 (a melanoma-associated antigen) through a high affinity T cell receptor binding domain, and through an anti-CD3 effector domain re-directs any cytotoxic T cell, regardless of its intrinsic specificity, to kill gp100-expressing tumor cells. In patients with metastatic melanoma, tebentafusp showed anti-tumor activity and manageable and predictable side effects. Notably, tebentafusp induced an increase in serum CXCL10 (a T cell attractant), and a reduction in circulating CXCR3+ CD8+ T cells together with an increase in cytotoxic T cells in the tumor microenvironment (TME). Furthermore, the appearance of rash, likely due to cytotoxic T cells targeting of gp100-expressing skin melanocytes, or an increase in serum CXCL10 showed a positive association with patient survival. Taken together, these results suggest that re-directing T cells using a gp100-targeting T cell receptor/anti-CD3 bispecific fusion protein may provide benefit to patients with metastatic melanoma.
Project description:A novel affinity-tuned dual-checkpoint bispecific antibody with potent PD-L1 and moderate CD47 affinity was designed to improve the selectivity to TME and thus enhance antitumor immunity and efficacy. The gene expression analysis using Nanostring platform was performed to examine the immune cell modulation in TME following the CD47/PD-L1 bispecific treatment.
Project description:A novel affinity-tuned dual-checkpoint bispecific antibody with potent PD-L1 and moderate CD47 affinity was designed to improve the selectivity to TME and thus enhance antitumor immunity and efficacy. The scRNAseq analysis was performed to examine the immune cell modulation in TME following the CD47/PD-L1 bispecific treatment.