Feasibility and Safety of Personalized, Multi-Target, Adoptive Cell Therapy (IMA101): First-in-Human Clinical Trial in Patients with Advanced Metastatic Cancer.

IMA101 is an actively personalized, multi-targeted adoptive cell therapy (ACT), whereby autologous T cells are directed against multiple novel defined peptide-HLA (pHLA) cancer targets. HLA-A*02:01-positive patients with relapsed/refractory solid tumors expressing ≥1 of 8 predefined targets underwent leukapheresis. Endogenous T cells specific for up to 4 targets were primed and expanded in vitro. Patients received lymphodepletion (fludarabine, cyclophosphamide), followed by T-cell infusion and low-dose IL2 (Cohort 1). Patients in Cohort 2 received atezolizumab for up to 1 year (NCT02876510). Overall, 214 patients were screened, 15 received lymphodepletion (13 women, 2 men; median age, 44 years), and 14 were treated with T-cell products. IMA101 treatment was feasible and well tolerated. The most common adverse events were cytokine release syndrome (Grade 1, n = 6; Grade 2, n = 4) and expected cytopenias. No patient died during the first 100 days after T-cell therapy. No neurotoxicity was observed. No objective responses were noted. Prolonged disease stabilization was noted in three patients lasting for 13.7, 12.9, and 7.3 months. High frequencies of target-specific T cells (up to 78.7% of CD8+ cells) were detected in the blood of treated patients, persisted for >1 year, and were detectable in posttreatment tumor tissue. Individual T-cell receptors (TCR) contained in T-cell products exhibited broad variation in TCR avidity, with the majority being low avidity. High-avidity TCRs were identified in some patients' products. This study demonstrates the feasibility and tolerability of an actively personalized ACT directed to multiple defined pHLA cancer targets. Results warrant further evaluation of multi-target ACT approaches using potent high-avidity TCRs. See related Spotlight by Uslu and June, p. 865.

T cell receptor dynamic and transcriptional determinants of T cell expansion in glioma-infiltrating T cells.

Background: Glioblastoma (GBM) is characterized by low numbers of glioma-infiltrating lymphocytes (GIL) with a dysfunctional phenotype. Whether this dysfunctional phenotype is fixed or can be reversed upon ex vivo culturing is poorly understood. The aim of this study was to assess T cell receptor (TCR)-dynamics and -specificities as well as determinants of in vitro GIL expansion by sequencing-based technologies and functional assays to explore the use of GIL for cell therapy. Methods: By means of flow cytometry, T cell functionality in GIL cultures was assessed from 9 GBM patients. TCR beta sequencing (TCRB-seq) was used for TCR repertoire profiling before and after in vitro expansion. Microarrays or RNA sequencing (RNA-seq) were performed from 6 micro-dissected GBM tissues and healthy brain RNA to assess the individual expression of GBM-associated antigens (GAA). GIL reactivity against in silico predicted tumor-associated antigens (TAA) and patient-individual GAA was assessed by ELISpot assay. Combined ex vivo single cell (sc)TCR-/RNA-seq and post-expansion TCRB-seq were used to evaluate transcriptional signatures that determine GIL expansion. Results: Human GIL regains cellular fitness upon in vitro expansion. Profound TCR dynamics were observed during in vitro expansion and only in one of six GIL cultures, reactivity against GAA was observed. Paired ex vivo scTCR/RNA-seq and TCRB-seq revealed predictive transcriptional signatures that determine GIL expansion. Conclusions: Profound TCR repertoire dynamics occur during GIL expansion. Ex vivo transcriptional T cell states determine expansion capacity in gliomas. Our observation has important implications for the use of GIL for cell therapy including genetic manipulation to maintain both antigen specificity and expansion capacity.

Phase I/II Multicenter Trial of a Novel Therapeutic Cancer Vaccine, HepaVac-101, for Hepatocellular Carcinoma.

PURPOSE: Immunotherapy for hepatocellular carcinoma (HCC) shows considerable promise in improving clinical outcomes. HepaVac-101 represents a single-arm, first-in-human phase I/II multicenter cancer vaccine trial for HCC (NCT03203005). It combines multipeptide antigens (IMA970A) with the TLR7/8/RIG I agonist CV8102. IMA970A includes 5 HLA-A*24 and 7 HLA-A*02 as well as 4 HLA-DR restricted peptides selected after mass spectrometric identification in human HCC tissues or cell lines. CV8102 is an RNA-based immunostimulator inducing a balanced Th1/Th2 immune response. PATIENTS AND METHODS: A total of 82 patients with very early- to intermediate-stage HCCs were enrolled and screened for suitable HLA haplotypes and 22 put on study treatment. This consisted in a single infusion of low-dose cyclophosphamide followed by nine intradermal coadministrations of IMA970A and CV8102. Only patients with no disease relapse after standard-of-care treatments were vaccinated. The primary endpoints of the HepaVac-101 clinical trial were safety, tolerability, and antigen-specific T-cell responses. Secondary or exploratory endpoints included additional immunologic parameters and survival endpoints. RESULTS: The vaccination showed a good safety profile. Transient mild-to-moderate injection-site reactions were the most frequent IMA970A/CV8102-related side effects. Immune responses against ≥1 vaccinated HLA class I tumor-associated peptide (TAA) and ≥1 vaccinated HLA class II TAA were respectively induced in 37% and 53% of the vaccinees. CONCLUSIONS: Immunotherapy may provide a great improvement in treatment options for HCC. HepaVac-101 is a first-in-human clinical vaccine trial with multiple novel HLA class I- and class II-restricted TAAs against HCC. The results are initial evidence for the safety and immunogenicity of the vaccine. Further clinical evaluations are warranted.

Comparative evaluation of T-cell receptors in experimental glioma-draining lymph nodes.

BACKGROUND: Glioblastomas, the most common primary malignant brain tumors, are considered immunologically cold malignancies due to growth in an immune sanctuary site. While peptide vaccines have shown to generate intra-tumoral antigen-specific T cells, the identification of these tumor-specific T cells is challenging and requires detailed analyses of tumor tissue. Several studies have shown that CNS antigens may be transported via lymphatic drainage to cervical lymph nodes, where antigen-specific T-cell responses can be generated. Therefore, we investigated whether glioma-draining lymph nodes (TDLN) may constitute a reservoir of tumor-reactive T cells. METHODS: We addressed our hypothesis by flow cytometric analyses of chicken ovalbumin (OVA)-specific CD8+ T cells as well as T-cell receptor beta (TCRß) next-generation-sequencing (TCRß-NGS) of T cells from tumor tissue, TDLN, spleen, and inguinal lymph nodes harvested from experimental mouse GL261 glioma models. RESULTS: Longitudinal dextramer-based assessment of specific CD8+ T cells from TDLN did not show tumor model antigen reactivity. Unbiased immunogenomic analysis revealed a low overlap of TCRß sequences from glioma-infiltrating CD8+ T cells between mice. Enrichment scores, calculated by the ratio of productive frequencies of the different TCRß-CDR3 amino-acid (aa) rearrangements of CD8+ T cells derived from tumor, TDLN, inguinal lymph nodes, and spleen demonstrated a higher proportion of tumor-associated TCR in the spleen compared to TDLN. CONCLUSIONS: In experimental glioblastoma, our data did not provide evidence that glioma-draining cervical lymph nodes are a robust reservoir for spontaneous glioma-specific T cells highlighting the requirement for detailed analyses of glioma-infiltrating T cells for the discovery of tumor-specific TCR.

Tryptophan metabolism drives dynamic immunosuppressive myeloid states in IDH-mutant gliomas.

The dynamics and phenotypes of intratumoral myeloid cells during tumor progression are poorly understood. Here we define myeloid cellular states in gliomas by longitudinal single-cell profiling and demonstrate their strict control by the tumor genotype: in isocitrate dehydrogenase (IDH)-mutant tumors, differentiation of infiltrating myeloid cells is blocked, resulting in an immature phenotype. In late-stage gliomas, monocyte-derived macrophages drive tolerogenic alignment of the microenvironment, thus preventing T cell response. We define the IDH-dependent tumor education of infiltrating macrophages to be causally related to a complex re-orchestration of tryptophan metabolism, resulting in activation of the aryl hydrocarbon receptor. We further show that the altered metabolism of IDH-mutant gliomas maintains this axis in bystander cells and that pharmacological inhibition of tryptophan metabolism can reverse immunosuppression. In conclusion, we provide evidence of a glioma genotype-dependent intratumoral network of resident and recruited myeloid cells and identify tryptophan metabolism as a target for immunotherapy of IDH-mutant tumors.

Heterogeneity of response to immune checkpoint blockade in hypermutated experimental gliomas.

Intrinsic malignant brain tumors, such as glioblastomas are frequently resistant to immune checkpoint blockade (ICB) with few hypermutated glioblastomas showing response. Modeling patient-individual resistance is challenging due to the lack of predictive biomarkers and limited accessibility of tissue for serial biopsies. Here, we investigate resistance mechanisms to anti-PD-1 and anti-CTLA-4 therapy in syngeneic hypermutated experimental gliomas and show a clear dichotomy and acquired immune heterogeneity in ICB-responder and non-responder tumors. We made use of this dichotomy to establish a radiomic signature predicting tumor regression after pseudoprogression induced by ICB therapy based on serial magnetic resonance imaging. We provide evidence that macrophage-driven ICB resistance is established by CD4 T cell suppression and Treg expansion in the tumor microenvironment via the PD-L1/PD-1/CD80 axis. These findings uncover an unexpected heterogeneity of response to ICB in strictly syngeneic tumors and provide a rationale for targeting PD-L1-expressing tumor-associated macrophages to overcome resistance to ICB.