RESUMEN
Glioblastoma (GBM) is an aggressive brain tumor with poor prognosis. Although immunotherapy is being explored as a potential treatment option for patients with GBM, it is unclear whether systemic immunotherapy can reach and modify the tumor microenvironment in the brain. We evaluated immune characteristics in patients receiving the anti-PD1 immune checkpoint inhibitor Nivolumab one week prior to surgery, compared to control patients receiving salvage resection without prior Nivolumab treatment. We observed saturating levels of Nivolumab bound to intratumorally- and tissue-resident T cells in the brain, implicating saturating levels of Nivolumab reaching brain tumors. Following Nivolumab treatment, significant changes in T-cell activation and proliferation were observed in the tumor resident T-cell population, and peripheral T cells upregulated chemokine receptors related to brain homing. A strong Nivolumab-driven upregulation in compensatory checkpoint inhibition molecules, TIGIT, LAG-3, TIM-3 and CTLA-4 was observed, potentially counteracting the treatment effect. Finally, tumor-reactive tumor-infiltrating lymphocytes (TILs) were found in a subset of Nivolumab-treated patients with prolonged survival, and neoantigen-reactive T cells were identified in both TILs and blood. This indicates a systemic response towards GBM in a subset of patients, which was further boosted by Nivolumab, with T-cell responses towards tumor-derived neoantigens. Our study demonstrates that Nivolumab does reach the GBM tumor lesion and enhances antitumor T-cell responses both intratumorally and systemically. However, various anti-inflammatory mechanisms mitigate the clinical efficacy of the anti-PD1 treatment.
RESUMEN
BACKGROUND: Glioblastoma is a highly aggressive type of brain tumour for which there is no curative treatment available. Immunotherapies have shown limited responses in unselected patients, and there is an urgent need to identify mechanisms of treatment resistance to design novel therapy strategies. METHODS: Here we investigated the phenotypic and transcriptional dynamics at single-cell resolution during nivolumab immune checkpoint treatment of glioblastoma patients. RESULTS: We present the integrative paired single-cell RNA-seq analysis of 76 tumour samples from patients in a clinical trial of the PD-1 inhibitor nivolumab and untreated patients. We identify a distinct aggressive phenotypic signature in both tumour cells and the tumour microenvironment in response to nivolumab. Moreover, nivolumab-treatment was associated with an increased transition to mesenchymal stem-like tumour cells, and an increase in TAMs and exhausted and proliferative T cells. We verify and extend our findings in large external glioblastoma dataset (n = 298), develop a latent immune signature and find 18% of primary glioblastoma samples to be latent immune, associated with mesenchymal tumour cell state and TME immune response. Finally, we show that latent immune glioblastoma patients are associated with shorter overall survival following immune checkpoint treatment (p = 0.0041). CONCLUSIONS: We find a resistance mechanism signature in a quarter of glioblastoma patients associated with a tumour-cell transition to a more aggressive mesenchymal-like state, increase in TAMs and proliferative and exhausted T cells in response to immunotherapy. These patients may instead benefit from neuro-oncology therapies targeting mesenchymal tumour cells.
RESUMEN
Background: Glioblastoma is an aggressive brain cancer with no possibility for cure. Treatment and survival have only improved slightly since 2005 when the current regime was implemented. The limited improvements in the treatment of glioblastoma may reflect our poor understanding of the disease. We hypothesize that systematically collected translational data will improve knowledge and hereby treatment. Methods: We have been performing whole exome sequencing in glioblastoma tumor tissue since 2016 and whole genome sequencing (WGS) since 2020 with the aim of offering experimental treatment. Results: We have sequenced 400+ GBM patients and from these 100+ are paired tumor samples from relapse surgery. To develop genomic profiling and to increase the information on each patient´s contribution, we have initiated the Neurogenome study as of June 2022. The Neurogenome protocol is a national, comprehensive, translational, and omic protocol. It is a continuation of 2 previous protocols from 2016 and forth in our department, but with more substudies added, focusing on the translational and clinical utility. We collect and analyze data from an out-patient clinic in a systematic approach to a number of subprojects ranging from basic science to applied clinical science, including clinical trials. Conclusions: The protocol will act as a backbone for future projects in the national research center, Danish Comprehensive Cancer Center-Brain Tumor Center with the overall aim to select eligible patients for experimental treatment based upon genomic alterations. The article will present the Neurogenome setup and a presentation of selected projects that are based upon inclusion.