Autologous huMNC2-CAR44 or huMNC2-CAR22 T Cells for Breast Cancer Targeting Cleaved Form of MUC1 (MUC1*)

Recent trials have demonstrated that chimeric antigen receptor (CAR)-modified T cells (CAR-T cells) specific for the CD19 molecule can mediate marked tumor regression in a subset of patients with advanced acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). It would be ideal to extend CAR-T cell therapy to common epithelial cancers. However, this poses several challenges, including the identification of molecules expressed on tumor cells that can be targeted safely with CAR-T cells. Minerva Biotechnologies has developed a CAR T product (huMNC2-CAR44 or huMNC2-CAR22) that targets the extra cellular domain of the cleaved form of MUC1 (called MUC1\*), which is the form of MUC1 that functions as a growth factor receptor and is present on large percentage of solid tumors, including breast tumors. The antibody targeting head of huMNC2-CAR44 or huMNC2-CAR22 specifically recognizes a cancerous form of MUC1\* and does not bind to another form of cleaved MUC1 that is present on some normal tissues that also have a rapid turnover. To be clear, patients will receive either huMNC2-CAR44 or huMNC2-CAR22, but not a combined product.

The huMNC2-CAR44 product consists of autologous T cells that are isolated from cancer patients, transduced with a proprietary lentiviral vector backbone manufactured under cGMP and containing sequences for a human CD8 alpha leader sequence, humanized MNC2-scFv (MUC1\* targeting head), portions of human CD8 hinge and transmembrane domains, and human 4-1BB and human CD3-zeta costimulatory domains. The huMNC2-CAR44 transduced T cells are antigen-stimulated in vitro, with a synthetic MUC1\* extracellular domain peptide. The CAR T cells are then ready for administration to the patient. Alternatively, the CAR T cells can be cryopreserved, then administered to the patient after thaw at bedside.

The huMNC2-CAR22 product is comprised of a CD8-α leader sequence, the huMNC2 scFv, a CD28 hinge and transmembrane region, followed by a CD28 co-stimulatory domain and a CD3-ζ signaling domain bearing two Tyrosine to Phenylalanine mutations in each of ITAMs 2 and 3 to minimize CAR T cell exhaustion and increase in vivo persistence. The huMNC2-CAR22 transduced T cells are not antigen-stimulated. The CAR T cells can be cryopreserved, then administered to the patient after thaw at bedside.

The investigators propose to evaluate the safety and preliminary anti-tumor activity of adoptively transferred autologous T cells genetically modified to express a CAR that targets MUC1\*, huMNC2-CAR44 or huMNC2-CAR22, in Phase I/II clinical trials in patients with metastatic MUC1\* positive breast cancers.