Hyper-Interferon Sensitive influenza induces adaptive immune responses and overcomes resistance to anti-PD-1 in murine non-small cell lung cancer.

Despite recent advances in immunotherapy with immune checkpoint inhibitors (ICI), many patients with non-small cell lung cancer (NSCLC) fail to respond or develop resistance after an initial response. In situ vaccination (ISV) with engineered viruses has emerged as a promising antigen-agnostic strategy that can both condition the tumor microenvironment (TME) and augment anti-tumor T cell responses to overcome immune resistance. We engineered a live attenuated viral vaccine, Hyper-Interferon Sensitive virus (HIS), by conducting a genome-wide functional screening and introducing eight interferon (IFN)-sensitive mutations in the influenza genome. Compared to wild-type (WT) influenza, HIS replication was attenuated in immunocompetent hosts, enhancing its potential as a safe option for cancer therapy. HIS ISV elicited robust yet transient type I IFN responses in murine NSCLCs, leading to an enrichment of polyfunctional effector Th1 CD4 and cytotoxic CD8 T cells into the tumor. HIS ISV demonstrated enhanced anti-tumor efficacy compared to WT in multiple syngeneic murine models of NSCLC with distinct driver mutations and varying mutational burden. This efficacy was dependent on host type 1 IFN responses and T lymphocytes. HIS ISV overcame resistance to anti-PD-1 in LKB-1 deficient murine NSCLC, resulting in improved overall survival and enduring systemic tumor-specific immunity. These studies provide compelling evidence to support further clinical evaluation of HIS as a novel 'off-the-shelf' ISV strategy for patients with NSCLC refractory to ICI.