Antigen-dependent IL-12 signaling in CAR T cells promotes regional to systemic disease targeting

• Published in: bioRxiv : the preprint server for biology
• Main Authors: Jun Lee, Eric Hee, Cullen, Cody, Murad, John P, Gumber, Diana, Park, Anthony K, Yang, Jason, Stern, Lawrence A, Adkins, Lauren N, Dhapola, Gaurav, Gittins, Brenna, Chung-Chang, Wen, Martinez, Catalina, Woo, Yanghee, Cristea, Mihaela, Rodriguez-Rodriguez, Lorna, Ishihara, Jun, Lee, John K, Forman, Stephen J, Wang, Leo D, Priceman, Saul J
• Format: Journal Article
• Language: English
• Published: United States 07.01.2023

Chimeric antigen receptor (CAR) T cell therapeutic responses are hampered by limited T cell trafficking, persistence, and durable anti-tumor activity in solid tumor microenvironments. However, these challenges can be largely overcome by relatively unconstrained synthetic engineering strategies, which are being harnessed to improve solid tumor CAR T cell therapies. Here, we describe fully optimized CAR T cells targeting tumor-associated glycoprotein-72 (TAG72) for the treatment of solid tumors, identifying the CD28 transmembrane domain upstream of the 4-1BB co-stimulatory domain as a driver of potent anti-tumor activity and IFNγ secretion. These findings have culminated into a phase 1 trial evaluating safety, feasibility, and bioactivity of TAG72-CAR T cells for the treatment of patients with advanced ovarian cancer ( NCT05225363 ). Preclinically, we found that CAR T cell-mediated IFNγ production facilitated by IL-12 signaling was required for tumor cell killing, which was recapitulated by expressing an optimized membrane-bound IL-12 (mbIL12) molecule on CAR T cells. Critically, mbIL12 cell surface expression and downstream signaling was induced and sustained only following CAR T cell activation. CAR T cells with mbIL12 demonstrated improved antigen-dependent T cell proliferation and potent cytotoxicity in recursive tumor cell killing assays and showed robust anti-tumor efficacy in human xenograft models of ovarian cancer peritoneal metastasis. Further, locoregional administration of TAG72-CAR T cells with antigen-dependent IL-12 signaling promoted durable anti-tumor responses against both regional and systemic disease in mice and was associated with improved systemic T cell persistence. Our study features a clinically-applicable strategy to improve the overall efficacy of locoregionally-delivered CAR T cells engineered with antigen-dependent immune-modulating cytokines in targeting both regional and systemic disease.