Multiplexed cytokine and antigen mRNA administration generates durable anti-tumor immunity against pancreatic cancer.

Immunotherapy has limited success in pancreatic ductal adenocarcinoma (PDAC) due to an immune exclusive tumor microenvironment (TME) that lacks many cytokines necessary for Natural Killer (NK) and T cell responses. Here, we design multiplexed mRNAs encoding interleukins, chemokines, and interferons as a safe and effective cytokine therapy for PDAC. Intratumoral injection of IL-12, IL-18, CCL5, CXCL10, and IFNβ mRNAs achieves robust yet transient cytokine expression, leading to NK and CD8+ T cell activation and reduced tumor growth and fibrosis in PDAC transplant mouse models. Combining cytokine with tumor antigen mRNAs enhances dendritic cell antigen presentation and CD8+ T cell priming locally and systemically that prolongs animal survival after a single dose. Remarkably, nanoparticle encapsulation of the cytokine/antigen mRNA cocktail allows systemic administration and local delivery to autochthonous PDAC tumors in mice, culminating in curative responses in 50% of animals and antigen-reactive T cell persistence. These results suggest that multiplexed mRNA approaches to deliver cytokines and antigens generally absent in the TME could pave the way for effective immunotherapy in PDAC.