Redirected Immune Cell Therapies

Chimeric antigen receptor (CAR) T cell therapies are able to generate deep and durable clinical responses in hematologic malignancies of the B-cell lineage. The manufacturing of these T cell-based therapies typically relies upon viral transduction of T cell-receptor (TCR) activated T cell followed by ex vivo expansion for 6 or more days prior to infusion. In addition to the required time and labor, the TCR/CD3 activation and ex vivo expansion leads to progressive differentiation of the CAR T cells with associated loss of anti-leukemic activity. We demonstrate that functional CAR T cells can be generated within less than 24 hours from peripheral blood-derived T cells without the need for prior T cell activation in a process that is significantly influenced by the medium formulation and geometry of the transduction vessel. Using several CAR models, we show that T cells generated using this simple and rapid manufacturing approach exhibit superior per-cell anti-leukemic compared to CAR T cells produced in the standard protocol. These data illustrate the potential for significantly reducing the time and cost of CAR T cell production. This will further extend the application of this therapy to patients with rapidly progressive disease as well as resource-poor healthcare settings.

Bispecific T cell engagers (bs-TCE) are a promising class of immune-oncology agents in targeted cancer immunotherapy. Classical bs-TCE designs consist of a tumor antigen-binding domain combined with a binding domain against the CD3 T-cell receptor-signaling complex. Irrespective of the bispecific antibody format used, CD3-based bs-TCEs have a number of disadvantages, which in part are explained by the fact that they activate all T-cells irrespective of lineage, which associates with serious adverse events as a result of exaggerated T cell activation and cytokine release in some patients, and limited efficacy due to T suppressor cell activation in others.

The development of bs-TCEs with increased tumor selectivity to widen the therapeutic window has high potential. Lava Therapeutics’ platform is based on the selective recruitment of Vγ9Vδ2 T cells for tumor targeting. This γδ T cell subset has been shown to display powerful innate anti-tumor immune effector activity with an ability to infiltrate human tumors in which its abundance in tumor-infiltrating lymphocytes has been shown to positively correlate with patient survival. I will discuss a novel class of bsTCEs designed to recruit Vγ9Vδ2-T cells for the development of next generation T cell engagers and cancer immunotherapies.

Bispecific T cell engagers represent a promising modality for redirection of T cells in immuno-oncology. In recent years, the field of T cell engagers developed from short half-life T cell engagers for hematological tumors towards half-life extended T cell engagers for the treatment of solid tumors. In this presentation, I will discuss the current advances and challenges of discovery of novel T cell engagers for solid tumors and provide mechanistic insights into the mode of action of the DLL3/CD3 ITE, a novel IgG-like bispecific T cell engaging antibody, which is currently in clinical development.

T cells are important to the initiation, prevention, and cure of many diseases. In the past several years, we have developed several tools to profile the T cell repertoire from T cell receptor diversity to T cell receptor affinity to multi-dimensional profiling of single T cells in high-throughput. In this talk, I will first introduce these tools and then give examples on how we use them to answer some of the fundamental questions in systems immunology, which in turn helps us design new approaches in immune engineering.

Tumor-associated macrophages (TAMs) promote metastasis and inhibit T cells, yet macrophages can be polarized to kill cancer cells. Macrophage polarization could thus be a strategy for controlling cancer. We show that macrophages from metastatic pleural effusions of breast cancer patients can be polarized to kill cancer cells with monophosphoryl lipid A (MPLA) and interferon γ (IFNγ). MPLA+IFNγ injected intratumorally or intraperitoneally reduces primary tumor growth and metastasis in breast cancer mouse models and suppresses metastasis and enhances chemotherapy response in an ovarian cancer model. Both macrophages and T cells are critical for the treatment’s anti-metastatic effects. MPLA+IFNγ stimulates type I IFN signaling, reprograms CD206+ TAMs to inducible NO synthase (iNOS)+ macrophages, and activates cytotoxic T cells through macrophage-secreted interleukin 12 (IL-12) and tumor necrosis factor α (TNFα). MPLA and IFNγ are used individually in clinical practice and together represent a previously unexplored approach for engaging a systemic anti-tumor immune response.

Donor lymphocyte infusion (DLI) is a standard of care and potentially curative immunotherapy for relapsed leukemia after allogeneic hematopoietic stem cell transplant (allo-SCT). Durable response is associated with reversal of exhaustion of bone marrow-infiltrating T cells. However, the exact transcriptional states of T cells mediating exhaustion, anti-leukemia responses, and resistance to DLI remain unclear. To map the dynamics of T cell states, we profiled viable cells from bone marrow mononuclear cells before and after DLI from patients with relapsed CML after allo-SCT using single-cell RNA-seq. To overcome the limitations of experimental design inherent to clinical studies, we adapted statistical techniques and developed novel longitudinal and integrative probabilistic models. Gaussian Process regression models were used to delineate temporal dynamics of exhausted T cells that are predictive of response or expand in Responders. Using a Bayesian framework, we integrated ATAC-seq from sorted subsets of T cells with scRNA-seq data, to deconvolve the circuitry of T cell subsets underlying effective anti-leukemic response

Synthetic biology is driving a new era of medicine through the genetic programming of living cells. This transformative approach allows for the creation of engineered systems that intelligently sense and respond to diverse environments, ultimately adding specificity and efficacy that extends beyond the capabilities of molecular-based therapeutics. One particular focus has been on engineering bacteria for cancer therapy, where a multitude of studies have demonstrated selective colonization of solid tumors by bacteria, primarily due to reduced immune surveillance in tumor cores. In this talk, I will describe our laboratory's progress in building a multi-scale framework for engineering bacteria as a cancer therapy. We use a methodology that bridges in silico computational modeling, in vitro characterization and platform development, and in vivo mouse models for cancer. We will highlight recent examples of bacteria programmed to sense and respond to tumor environments and release specific therapeutic payloads ranging from cytotoxic to immunomodulatory agents.