CAR T cells targeting Nectin-4 safely overcome resistance to anti-Nectin-4 antibody-drug conjugate in solid tumors

CAR-T cell therapy to solid tumors faces substantial challenges. Lack of tumor specific antigen (TSA) predicts toxicities in vital organs. Nectin-4 is a cell adhesion molecule expressed at different levels in many solid tumors, including breast and urothelial carcinoma (UC). Enfortumab vedotin (EV), an antibody-drug conjugate (ADC) against Nectin-4, has significantly improved survival in patients with metastatic UC. Skin adverse reactions are frequently observed due to high Nectin-4 expression in keratinocytes. Here, we developed second-generation CAR T cells against Nectin-4 (N4CART) with a scFv that recognizes a tumor specific antigenic variant (TSAV) in human Nectin-4, not present in Nectin-4 expressed in skin keratinocytes. To study the effects of N4CART cell therapy, we used preclinical models of cell-derived xenografts (CDX) and patient-derived xenograft (PDX) of breast cancer expressing moderate to high levels of Nectin-4. We showed a marked efficacy in xenografted mouse models including EV-resisting, with induction of remissions in absence of skin toxicity. Interestingly, N4CART cells kill Nectin-4-positive breast, urothelial and colon tumor cells, which are also resistant to EV. Finally, we showed that the baboon-envelope pseudotyped lentiviral vectors (LV) outperformed VSVG-LVs for Nectin-4 CAR expressing in αβ T cells resulting in an efficient anti-tumoral response in PDX mice. Through TSAV and LV selection, our results open up a new avenue in the treatment of solid tumors by CAR-T cells.