Tripartite antigen-agnostic combination immunotherapy cures established poorly immunogenic tumors

Abstract

BackgroundSingle-agent immunotherapy has shown remarkable efficacy in selected cancer entities and individual patients. However, most patients fail to respond. This is likely due to diverse immunosuppressive mechanisms acting in a concerted way to suppress the host anti-tumor immune response. Combination immunotherapy approaches that are effective in such poorly immunogenic tumors mostly rely on precise knowledge of antigenic determinants on tumor cells. Creating an antigen-agnostic combination immunotherapy that is effective in poorly immunogenic tumors for which an antigenic determinant is not known is a major challenge.MethodsWe use multiple cell line and poorly immunogenic syngeneic, autochthonous, and autologous mouse models to evaluate the efficacy of a novel combination immunotherapy named tripartite immunotherapy (TRI-IT). To elucidate TRI-ITs mechanism of action we use immune cell depletions and comprehensive tumor and immune infiltrate characterization by flow cytometry, RNA sequencing and diverse functional assays.ResultsWe show that combined adoptive cellular therapy (ACT) with lymphokine-activated killer cells, cytokine-induced killer cells, Vγ9Vδ2-T-cells (γδ-T-cells) and T-cells enriched for tumor recognition (CTLs) display synergistic antitumor effects, which are further enhanced by cotreatment with anti-PD1 antibodies. Most strikingly, the full TRI-IT protocol, a combination of this ACT with anti-PD1 antibodies, local immunotherapy of agonists against toll-like receptor 3, 7 and 9 and pre-ACT lymphodepletion, eradicates and induces durable anti-tumor immunity in a variety of poorly immunogenic syngeneic, autochthonous, as well as autologous humanized patient-derived models. Mechanistically, we show that TRI-IT coactivates adaptive cellular and humoral, as well as innate antitumor immune responses to mediate its antitumor effect without inducing off-target toxicity.ConclusionsOverall, TRI-IT is a novel, highly effective, antigen-agnostic, non-toxic combination immunotherapy. In this study, comprehensive insights into its preclinical efficacy, even in poorly immunogenic tumors, and mode of action are given, so that translation into clinical trials is the next step.

Fes-deficient macrophages enhance CD8+T cell priming and tumour control through increased proinflammatory cytokine production and presentation

“…Since CTLs in the E0771 model only show an increase in PD-1 positivity following Dox therapy, we treated all mice with Dox, and either an isotype antibody control (IgG) or anti-PD-1 antibody (Figure 5A, D). In both the E0771 and B16F10 models, Dox, and anti-PD-1 treated fes +/+ mice show a decrease in tumour growth (Figure 5B, E), but no improvement in survival (Figure 5C, F) compared to Dox therapy alone, consistent with literature describing these tumour types as anti-PD-1 therapy resistant (27)(28)(29)(30)(31)(32). Impressively, fes -/mice treated only with Dox performed just as well (Fig 5B ), or better (Fig 5E) than fes +/+ treated with both Dox and anti-PD-1 therapy on delaying tumour growth.…”

“…This reprogramming of the tumour microenvironment to one that is more inflamed and anti-tumoural, was recapitulated in our study, which showed increased T cell activation and PD-1 expression in fes -/-, but not fes +/+ mice. Furthermore, E0771 and B16F10 models are commonly reported in the literature as resistant to anti-PD-1 therapy (27)(28)(29)(30)(31)(32)(58)(59)(60). This was seen in our studies where even in combination with Dox, anti-PD-1 elicited only a marginal improvement on tumour growth, and no improvement on survival in fes +/+ mice in either model.…”