Abstract 4549: Pemetrexed enhances anti-tumor efficacy of PD1 pathway blockade by promoting intra tumor immune response via immunogenic tumor cell death and T cell intrinsic mechanisms

Abstract

Background: Recently, pemetrexed and carboplatin in combination with PD–1 antibody (pembrolizumab) demonstrated markedly improved clinical outcome in NSCLC patients (KEYNOTE–021G trial) suggesting a positive interaction between pemetrexed–based chemotherapy and immunotherapy. However, the role of pemetrexed in modulating antitumor immune response is largely unknown. The objective of this study was to characterize the effects of pemetrexed on intra–tumor immune response in monotherapy and combination with carboplatin or PD–1 pathway blockade in preclinical models. Methods: Mice bearing syngeneic MC38 or Colon26 tumors were treated with pemetrexed with or without carboplatin or anti–mouse PD–L1 antibody (178G7). Immune cell subsets and immune–related changes in mouse tumor tissue and T cells were assessed by flow cytometry and gene expression analysis (Quantigene Plex and nanoString nCounter assays). Effects of pemetrexed on immunogenic cell death in tumor cells and mitochondrial respiration in T cells were evaluated by HMGB1 ELISA and Agilent Seahorse XF analysis, respectively. Results: In MC38 tumors, pemetrexed monotherapy demonstrated a trend towards an increased frequency of intratumoral leukocytes and total and cycling (Ki67+) T cells accompanied by immune–related gene expression changes indicative of enhanced antigen presentation, T cell infiltration and/or activation and down–modulation of the myeloid cell compartment. Immune gene expression signature induced by pemetrexed was largely unaffected by carboplatin. In both MC38 and Colon26 tumor cells, in vitro treatment with pemetrexed induced a robust release of HMGB1 indicative of immunogenic cell death. Proliferation of primary human T cells stimulated with CD3/CD28 was inhibited by pemetrexed in a dose–dependent manner. At clinically relevant concentrations pemetrexed also enhanced T cell activation phenotype exemplified by an increased frequency of CD137+, GITR+ and PD–L1+ T cells as well as upregulation of multiple interferon gamma–induced genes, and increased mitochondrial respiration. In both MC38 and Colon26 models, treatment with pemetrexed and 178G7 demonstrated a combination benefit compared to either monotherapy, and nCounter profiling of Colon26 tumors followed by Ingenuity Pathway Analysis revealed that improved antigen presentation, enhanced T cell and cytokine signaling and an engagement of CD4+ T cell–mediated immunity might underlie this combination effect. Conclusions: Pemetrexed promotes intra–tumor T cell–mediated immune response through immunogenic tumor cell death and increased activation and metabolic fitness of T cells leading to an enhanced anti–tumor efficacy in combination with PD–L1 antibody. Citation Format: Ruslan Novosiadly, David Schaer, Nelusha Amaladas, Erik Rasmussen, Zhao Hai Lu, Andreas Sonyi, Carmine Carpenito, Yanxia Li, Shuang Luo, Andrew Capen, Catalina Meyer, Xiaodong Huang, Jason Manro, Gregory Donoho, Thompson Doman, Gerald Hall, Sandaruwan Geeganage, Michael Kalos. Pemetrexed enhances anti-tumor efficacy of PD1 pathway blockade by promoting intra tumor immune response via immunogenic tumor cell death and T cell intrinsic mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4549.

Chemotherapy in combination with immune checkpoint inhibitors for the first-line treatment of patients with advanced non-small cell lung cancer: A systematic review and literature-based meta-analysis.

“…Depending on results after a longer follow-up, this may warrant further exploration in a hypothetical randomized trial. There could also be differences in the immunogenic activities of the chemotherapy compounds combined with ICPI, as reported by Novosiadly et al (23), suggesting differently an immunomodulatory effect of pemetrexed compared to paclitaxel. However, the magnitude of the effect we observed in our analysis with the Keynote 407 trial, which combined the anti-PD-1 pembrolizumab with paclitaxel or nab-paclitaxel in squamous histology, appears similar to other Keynote trial results.…”

Blood T cell diversity associated with the prognosis of advanced non‐small cell lung carcinoma treated with first‐line pemetrexed based chemotherapy

“…There have been only a few previous studies on the effects of pemetrexed on immune function, primarily on animals or in vitro studies 14,15 . It has been found that when pemetrexed is used in combination with anti‐PD‐L1 antibody, antitumor effects are increased and significant inflammation/immune activation is observed in animal experiments 3,14,16 . Meanwhile, the immunoregulatory effects of platinum have both negative regulatory effects 17 and positive regulatory effects 18–22 .…”

Immunogenic Cell Death and Elimination of Immunosuppressive Cells: A Double-Edged Sword of Chemotherapy

“…Pemetrexed, classically used in NSCLC adenocarcinoma, has also shown in vitro its ability to induce ICD, with significant release of HMGB1 [37], calreticulin exposure and interferon Type I [38].…”

“…Based on in vitro data, pemetrexed appears to be the best chemotherapy to associate with platinum in lung cancer [37,38]. In vivo analyses are needed to confirm this hypothesis and validate this choice as first line therapy in combination with pembrolizumab.…”