Tumor-targeted IL-10 synergizes with IL-2 to enhance antitumor immunity while minimizing immune-related adverse events

Tumor-targeting cytokines have emerged as a promising strategy for cancer immunotherapy, although their mechanisms of action often remain complex. In this study, we develop an approach by combining tumor-targeted IL-10 (CmAb-(IL10)2) with IL-2 (CmAb-IL2) to enhance antitumor immunity while minimizing immune-related adverse events (irAEs). We demonstrate that endogenous IL-10 plays a critical role in IL-2-mediated antitumor effects, and that the combination of CmAb-(IL10)2 and CmAb-IL2 preferentially expands less-exhausted CD8+ T cells within tumors. Mechanistically, we identify that the IL-10/IL-10 receptor (IL-10R) axis in dendritic cells (DCs) is critical for mediating the efficacy of this combination therapy by promoting intratumoral DC function. Furthermore, we show that this combination enhances antitumor immune responses in humanized female mice and ex vivo patient-derived tumor fragments models. Our findings reveal that tumor-targeted IL-10 synergizes with IL-2 to enhance antitumor immunity through the IL-10/IL-10R/DC axis within tumors, while mitigating IL-2-associated irAEs through the IL-10/IL-10R/macrophage axis. This approach offers an IL-10 based strategy to improve the efficacy of immunotherapy while reducing irAEs. IL2-based immunotherapies enhance anti-tumor immune responses, however, there is a significant risk of severe immune-related adverse events (irAEs). Here the authors show that combining a tumor-targeting cetuximab-based bispecific IL10 fusion protein with tumor-targeted IL2 enhances antitumor immunity and controls tumor growth while reducing IL2-associated irAEs through distinct IL-10R functions in dendritic cells and macrophages.