SBIR: In vivo engineering of multifaceted B7H3.CAR-T cells for cellular immunotherapy of pancreatic ductal adenocarcinoma

Project Summary T-cells modified with chimeric antigen receptor against unique cancer antigens i.e., CAR-T, represent a promising form of immunotherapy for cancer, but are currently limited by production time and costs to prepare the engineered T-cells ex vivo, as well as by modest efficacy against solid cancers due to poor tumor penetration. Rather than harvesting, activating, transducing, and expanding T-cells ex vivo, we believe direct engineering of CAR-T cells in vivo, by transducing circulating T-cells with high specificity, will reduce the time and cost of CAR-T therapy while also maximizing T-cell function by eliminating extended cultures in vitro. Mucommune has recently in-licensed a platform that enables exceptionally potent yet highly specific transduction of circulating T-cells, without first requiring T-cell activation, by combining both virological and chemical approaches. Specifically, it utilizes a LV system incorporating the Nipah virus fusion protein with its native tropism ablated and retargeted via anti-CD3 scFv, then formulates the resulting Nipah LV (NLV) with a proprietary combo of transduction enhancers. To date, we have shown that this new system can specifically transduce non-activated T-cells among circulating PBMCs in vivo, generate CD19-targeted CAR-T that effectively eliminate the highly aggressive BV173 lymphoma, and generate in vivo-engineered B7-H3-targeted CAR-T cells that eliminate metastatic non-small cell lung cancer (NSCLC) in vivo. In this proposal, we will extend this novel NLV platform to develop more effective T cell therapy against pancreatic ductal adenocarcinoma (PDAC). While B7-H3 is highly over-expressed in PDAC, two notable challenges with cellular therapies against PDAC are an immunosuppressive tumor microenvironment (iTME) and a stromal barrier that limits access of immune cells into the tumor. Dotti and colleagues recently showed that dual IL-15+GPC3.CAR-T cells markedly improved objective response rates in patients compared to GPC3.CAR-T, and that expression of the chemokine receptor CCR2b can greatly increase migration of CAR-T cells into solid tumors. Thus, we believe in vivo engineered multi-functional CAR-T cells comprising CCR2b, IL-15 and B7-H3.CAR are uniquely suited to address the challenges with PDAC. in Aim 1, we will engineer and characterize NLVs that encode all three elements, and evaluate their transduction efficiency in vivo as well as effectiveness in co-culture models with different PDAC cell lines and PDAC patient derived xenografts (PDX). In Aim 2, we will assess anti-tumor efficacy, prolonged survival and reduction in metastases of in vivo engineered CAR-T cells vs. conventional CAR-T in PDX mouse models, as well as rigorously characterize the phenotypes of the resulting CAR-T cells. If successful, our work will likely markedly expand the clinical adoption of CAR-T therapy, both by lowering costs but also potentially broadening their use for treatment of solid tumors, enabling CAR-T therapy to potentially become a front-line therapy for PDAC.