IL12-engineered human PSMA-CAR T cells for the treatment of advanced prostate cancer

Adoptive cell therapies used to treat advanced prostate cancer are being developed to target several tumor-associated antigens, including prostate-specific membrane antigen (PSMA). Chimeric antigen receptor (CAR) T cell therapy using the single chain variable fragment (scFv) derived from the humanized murine mAb clone, J591, as the antigen-binding domain has shown promising anti-tumor activity. However, it has also been associated with macrophage activation syndrome and other unwanted toxicities, highlighting the need for more specific and human-derived antigen-binders with optimized construct designs for improved safety and efficacy. Here, we optimize a human scFv-based PSMA-targeted CAR (hPSMA-CAR) with highly selective PSMA targeting. We further introduce a membrane-bound IL-12 (mbIL12) molecule, which enhances potency with increased T cell expansion, IFNy production and anti-tumor cell activity <i>in vitro</i> . Using two clinically-relevant bone-metastatic prostate cancer models, we show that mbIL12-engineered hPSMA-CAR T cells drive potent <i>in vivo</i> anti-tumor responses. In summary, we have developed a promising therapeutic that has potential to promote safe and effective treatment of advanced PSMA+ prostate cancer.