SBIR: In vivo engineering of B7-H3.CAR-T cells for ovarian cancer therapy

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 for engineering B7-H3.CAR-T cells in vivo to develop more effective T cell therapy against ovarian cancer (OC). Notably, B7-H3 is highly over-expressed in OC, and there is an ongoing clinical trial at UNC that investigates B7-H3.CAR-T cells prepared using conventional ex vivo manufacturing. A particular challenge with cell therapies against OC is the immunosuppressive tumor microenvironment (iTME) imposed by solid OC tumors. Dotti and colleagues recently showed that dual IL-15 and GPC3.CAR expression can markedly improve the objective response rate in patients compared to GPC3.CAR alone. Thus, we believe in vivo engineered IL-15.B7-H3.CAR-T should also offer considerable promise against OC. in Aim 1, we will first engineer and characterize NLVs that encode both B7-H3.CAR and different forms of IL-15, and evaluate their transduction efficiency in vivo as well as the effectiveness of IL-15.B7-H3.CAR in co-culture models with different OC cell lines. In Aim 2, we will rigorously characterize NLV-induced in vivo CAR-T, including T cell memory and exhaustion, compared to conventional ex vivo engineering CAR-T cells. We will then assess anti-tumor efficacy, prolonged survival and reduction in metastases in both humanized OC models in NSG mice as well as in syngeneic OC models in immunocompetent mice. 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 OC.