Acquired resistance to cancer immunotherapy

In recent times, advances in cancer immunotherapy have yielded impressive, durable clinical responses in patients with varied subtypes of cancer. However, a significant proportion of patients who initially demonstrate encouraging tumor regression develop resistance and progress over time. The identification of novel therapeutic approaches to overcome resistance may result in significantly improved clinical outcomes and remains an area of high scientific priority. This review aims to summarize the current knowledge regarding the role of both tumor-intrinsic and tumor-extrinsic factors in the development of resistance to cancer immunotherapy and to discuss current and possible future therapeutic strategies targeting these mechanisms

Cancer immunotherapy in patients with brain metastases

The exclusion of “real-world” patients from registration clinical trials of cancer immunotherapy represents a significant emerging issue. For instance, a large fraction of cancer patients develops brain metastases during the course of the disease, but results from large prospective clinical trials investigating this considerable proportion of the cancer patient population are currently lacking. To provide a useful tool for the clinician in a “real-world” setting, we have reviewed the available literature regarding the safety and efficacy of immune check-point inhibitors in patients with cancer metastatic to the brain. Overall, these data provide encouraging evidence that these therapeutic agents can induce intracranial objective responses, particularly in patients with asymptomatic and previously untreated brain metastases. Larger prospective studies are needed to confirm these initial results

Evidence of T cell activation and intratumoral nivolumab-presence in glioblastoma patients treated with nivolumab and bevacizumab

Glioblastoma (GBM) is an aggressive brain tumor with a dismal prognosis. Salvage neurosurgical resection is performed if possible and GBM patients are hereafter treated with Stupp’s regime as standard treatment in the primary setting. However, after relapse, treatment in the recurrent setting shows very limited effect. We are monitoring the immune system of patients participating in a phase II clinical trial, where patients with recurrent GBM receive Nivolumab and Bevacizumab, treatments blocking PD1 and VEGF, respectively. The clinical trial consists of two arms. Arm A includes patients where surgical removal of the tumor is possible, and arm B includes patients who are only able to receive medical treatment. Arm A has received Nivolumab 7 days prior to surgery. Single cells suspension was produced from the resected tumors and blood samples was collected from patients through the course of treatment, wherefrom PBMCs (peripheral blood mononuclear cells) were purified. All samples were immunophenotyped using multi-color flow cytometry, to identify and follow the distribution of various immune cell types, and determine their expression of activating and inhibitory molecules over the course of treatment, in the periphery and in the tumor. An activated subset of T cells was characterized by CD103 (tissue residence), CD39 (antigen exposure) and CD69 (cytotoxicity). Such T cell populations were significantly enriched in the tumor. Importantly, we could demonstrate the presence of Nivolumab in the tumor, using an anti-IgG4 antibody to detect Nivolumab binding to T cells. We observed IgG4 positive T cell in the tumor digest, suggesting T cells binding Nivolumab are present in the tumor. Additional data analysis will be performed prior to the conference. With this we hope to gain further knowledge of the immune system’s role in tumor clearance in the brain and the impact of immunotherapy hereupon

Nivolumab and bevacizumab for recurrent glioblastoma; t-cell reactivity against autologous tumor cells

INTRODUCTION: Glioblastoma is an aggressive brain tumor with a median survival of 14.6 months. We have no standard treatment for relapse and known options have limited effect. Novel treatments are necessary to improve survival and quality of life. METHODS: We present our trial; phase II open label, two-armed translational study of Nivolumab and Bevacizumab for recurrent GBM, who have failed Stupp’s regimen. Patients are included in two arms depending on the possibility of salvage neurosurgical resection. Both arms receive Nivolumab and Bevacizumab administrated every second weekend, and the surgical arm also receive Nivolumab 7 days prior surgery. Forty-four patients were included by January 2021; 20 in each arm (four screen-failures). In the surgical arm, 20 fresh tumor samples as well as paired tissue from primary tumor were available. Tumor infiltrating lymphocytes (TILs) and tumor digest were produced in vitro from recurrent settings. Young TILs were expanded from fresh tumor fragments after minimal-culture, whereas rapidly expanded TILs (REP TILs) were obtained after massive expansion. By intracellular cytokine staining, we investigated the TIL reactivity after exposure to autologous tumor digest in order to evaluate whether the TILs were tumor-reactive, non-reactive or bystanders. RNA and whole exome sequencing were available before and after treatment. RESULTS: Material from 19 patients was analyzed (one out of the 20 collected biopsies was limited in size, therefore no tumor digest could be produced). Four out of 19 TIL samples showed tumor reactivity after exposure to the autologous tumor digest. Tumor reactivity was ranged between 1,2 to 13,6 tox% in CD8+ TILs and between 2,8 to 10,9 tox% in CD4+ TILs. By flowcytometry we found, IgG4+ CD3+ TILS from tumor biopsies, meaning that Nivolumab were found in the brain. Currently controls are included to evaluate these results. CONCLUSIONS: Updated results will be presented at SNO

Immunologic Characterization and T cell Receptor Repertoires of Expanded Tumor-infiltrating Lymphocytes in Patients with Renal Cell Carcinoma

The successful use of expanded tumor-infiltrating lymphocytes (TIL) in adoptive TIL therapies has been reported, but the effects of the TIL expansion, immunophenotype, function, and T cell receptor (TCR) repertoire of the infused products relative to the tumor microenvironment (TME) are not well understood. In this study, we analyzed the tumor samples (n = 58) from treatment-naive patients with renal cell carcinoma (RCC), "pre-rapidly expanded" TILs (pre-REP TIL, n= 15) and "rapidly expanded" TILs (REP TIL, n = 25) according to a clinical-grade TIL production protocol, with single-cell RNA (scRNA)+TCR alpha beta-seq (TCR alpha beta sequencing), TCR beta-sequencing (TCR beta-seq), and flow cytometry. REP TILs encompassed a greater abundance of CD4(+) than CD8(+) T cells, with increased LAG-3 and low PD-1 expressions in both CD4(+) and CD8(+) T cell compartments compared with the pre-REP TIL and tumor T cells. The REP protocol preferentially expanded small clones of the CD4(+) phenotype (CD4, IL7R, KLRB1) in the TME, indicating that the largest exhausted T cell clones in the tumor do not expand during the expansion protocol. In addition, by generating a catalog of RCC-associated TCR motifs from >1,000 scRNA+TCR alpha beta-seq and TCR beta-seq RCC, healthy and other cancer sample cohorts, we quantified the RCC-associated TCRs from the expansion protocol. Unlike the low-remaining amount of anti-viral TCRs throughout the expansion, the quantity of the RCC-associated TCRs was high in the tumors and pre-REP TILs but decreased in the REP TILs. Our results provide an in-depth understanding of the origin, phenotype, and TCR specificity of RCC TIL products, paving the way for a more rationalized production of TILs.Significance: TILs are a heterogenous group of immune cells that recognize and attack the tumor, thus are utilized in various clinical trials. In our study, we explored the TILs in patients with kidney cancer by expanding the TILs using a clinical-grade protocol, as well as observed their characteristics and ability to recognize the tumor using in-depth experimental and computational tools.Peer reviewe