Science Translational Medicine | September 8, 2021

Hotz C, Wagenaar TR, Gieseke F, Bangari DS, Callahan M, Cao H, Diekmann J, Diken M, Grunwitz C, Hebert A, Hsu K, Bernardo M, Karikó K, Kreiter S, Kuhn AN, Levit M, Malkova N, Masciari S, Pollard J, Qu H, Ryan S, Selmi A, Schlereth J, Singh K, Sun F, Tillmann B, Tolstykh T, Weber W, Wicke L, Witzel S, Yu Q, Zhang YA, Zheng G, Lager J, Nabel GJ, Sahin U and Wiederschain D

Science translational medicine. 2021;13:eabc7804

http://doi.org/10.1126/scitranslmed.abc7804

Abstract

Local immunotherapy ideally stimulates immune responses against tumors while avoiding toxicities associated with systemic administration. Current strategies for tumor-targeted, gene-based delivery, however, are limited by adverse effects such as off-targeting or antivector immunity. We investigated the intratumoral administration of saline-formulated messenger (m)RNA encoding four cytokines that were identified as mediators of tumor regression across different tumor models: interleukin-12 (IL-12) single chain, interferon-α (IFN-α), granulocyte-macrophage colony-stimulating factor, and IL-15 sushi. Effective antitumor activity of these cytokines relied on multiple immune cell populations and was accompanied by intratumoral IFN-γ induction, systemic antigen-specific T cell expansion, increased granzyme B⁺ T cell infiltration, and formation of immune memory. Antitumor activity extended beyond the treated lesions and inhibited growth of distant tumors and disseminated tumors. Combining the mRNAs with immunomodulatory antibodies enhanced antitumor responses in both injected and uninjected tumors, thus improving survival and tumor regression. Consequently, clinical testing of this cytokine-encoding mRNA mixture is now underway.