Abstract 4563: Local and abscopal effects in oncolytic virotherapy are boosted by immune checkpoint blockade, immunogenic chemotherapy, or IFNAR blockade

Athough the clinical efficacy of oncolytic viruses has been demonstrated for local treatment, the ability to induce immune-mediated regression of distant metastases is still poorly documented. We here report that an engineered oncolytic Vaccinia Virus, VV WR -TK - RR - -Fcu1, is able to induce an immunogenic cell death and thus to generate a systemic immune response. Effect on tumor growth and survival is largely driven by CD8 + T-cells, and we could demonstrate that the immune cell infiltrate in the tumor could be reprogrammed towards a higher ratio of effector T-cells to regulatory CD4 + T-cells. The key role of the type 1-IFN pathway in oncolytic virotherapy was also highlighted, and we could show a strong abscopal response in Ifnar -/- tumors. In this model, the single administration of the virus directly into the tumors, on one flank, led to regression in the contralateral flank (i.e. opposite to the virus injection site). Moreover, we observed that these effects are further enhanced when the oncolytic treatment is combined with either immunogenic chemotherapy such as oxaliplatin, or with immune checkpoint blockers such as anti-PD-1 or anti-CTLA-4. Altogether, these data suggest that local oncolytic virotherapy in patients with tumors altered in IFNAR signaling could increase immune-mediated abscopal regression of distant metastases. Citation Format: Laetitia Fend, Takahiro Yamazaki, Xavier Preville, Eric Quemeneur, Oliver Kepp, Julien Adam, Aurelien Marabelle, Jonathan Pitt, Guido Kroemer, Laurence Zitvogel. Local and abscopal effects in oncolytic virotherapy are boosted by immune checkpoint blockade, immunogenic chemotherapy, or IFNAR blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4563. doi:10.1158/1538-7445.AM2017-4563