Immunotherapy has become a powerful clinical strategy for treating cancer. The number of immunotherapy drug approvals has been increasing, with numerous treatments in clinical and preclinical development. However, a key challenge in the broad implementation of immunotherapies for cancer remains the controlled modulation of the immune system, as these therapeutics have serious adverse effects including autoimmunity and nonspecific inflammation. Understanding how to increase the response rates to various classes of immunotherapy is key to improving efficacy and controlling these adverse effects. Advanced biomaterials and drug delivery systems, such as nanoparticles and the use of T cells to deliver therapies, could effectively harness immunotherapies and improve their potency while reducing toxic side effects. Here, we discuss these research advances, as well as the opportunities and challenges for integrating delivery technologies into cancer immunotherapy, and we critically analyse the outlook for these emerging areas.

Delivery technologies for cancer immunotherapy

Cellular senescence is characterized by stable cell-cycle arrest and a secretory program that modulates the tissue microenvironment1,2 Physiologically, senescence serves as a tumour-suppressive mechanism that prevents the expansion of premalignant cells3,4 and has a beneficial role in wound-healing responses5,6 Pathologically, the aberrant accumulation of senescent cells generates an inflammatory milieu that leads to chronic tissue damage and contributes to diseases such as liver and lung fibrosis, atherosclerosis, diabetes and osteoarthritis1,7 Accordingly, eliminating senescent cells from damaged tissues in mice ameliorates the symptoms of these pathologies and even promotes longevity1,2,8-10 Here we test the therapeutic concept that chimeric antigen receptor (CAR) T cells that target senescent cells can be effective senolytic agents We identify the urokinase-type plasminogen activator receptor (uPAR)11 as a cell-surface protein that is broadly induced during senescence and show that uPAR-specific CAR T cells efficiently ablate senescent cells in vitro and in vivo CAR T cells that target uPAR extend the survival of mice with lung adenocarcinoma that are treated with a senescence-inducing combination of drugs, and restore tissue homeostasis in mice in which liver fibrosis is induced chemically or by diet These results establish the therapeutic potential of senolytic CAR T cells for senescence-associated diseases

Senolytic CAR T cells reverse senescence-associated pathologies.

Chimeric antigen receptor (CAR) T cell therapy for B cell malignancies has surpassed expectations, driving an ever-expanding number of clinical trials and the first US Food and Drug Administration approvals of cell therapies for the treatment of cancer. This experience has illuminated some generalizable requirements for CAR T cell efficacy as well as the interplay between disease biology and clinical outcomes. Major CAR intrinsic variables affecting T cell behavior have been defined, and mechanisms of tumor resistance are increasingly understood. Here, we review the clinical experience with CAR T cells amassed to date, including but not limited to B cell malignancies, emphasizing factors associated with efficacy, resistance and major barriers to success. We also discuss how these insights are driving next-generation clinical trials, including those in solid tumors.

Clinical lessons learned from the first leg of the CAR T cell journey.

Tumor mutational burden (TMB), the total number of somatic coding mutations in a tumor, is emerging as a promising biomarker for immunotherapy response in cancer patients. TMB can be quantitated by a number of NGS-based sequencing technologies. Whole Exome Sequencing (WES) allows comprehensive measurement of TMB and is considered the gold standard. However, to date WES remains confined to research settings, due to high cost of the large genomic space sequenced. In the clinical setting, instead, targeted enrichment panels (gene panels) of various genomic sizes are emerging as the routine technology for TMB assessment. This stimulated the development of various methods for panel-based TMB quantification, and prompted the multiplication of studies assessing whether TMB can be confidently estimated from the smaller genomic space sampled by gene panels. In this review, we inventory the collection of available gene panels tested for this purpose, illustrating their technical specifications and describing their accuracy and clinical value in TMB assessment. Moreover, we highlight how various experimental, platform-related or methodological variables, as well as bioinformatic pipelines, influence panel-based TMB quantification. The lack of harmonization in panel-based TMB quantification, of adequate methods to convert TMB estimates across different panels and of robust predictive cutoffs, currently represents one of the main limitations to adopt TMB as a biomarker in clinical practice. This overview on the heterogeneous landscape of panel-based TMB quantification aims at providing a context to discuss common standards and illustrates the strong need of further validation and consolidation studies for the clinical interpretation of panel-based TMB values.

https://jitc.bmj.com/content/jitc/7/1/183.full.pdf

Tumor mutational burden quantification from targeted gene panels: major advancements and challenges

Chimeric antigen receptor (CAR) T-cell therapy targeting solid tumors has stagnated as a result of tumor heterogeneity, immunosuppressive microenvironments, and inadequate intratumoral T cell trafficking and persistence. Early (≤3 days) intratumoral presentation of CAR T cells post-treatment is a superior predictor of survival than peripheral persistence. Therefore, we have co-opted IL-8 release from tumors to enhance intratumoral T-cell trafficking through a CAR design for maximal antitumor activity in solid tumors. Here, we demonstrate that IL-8 receptor, CXCR1 or CXCR2, modified CARs markedly enhance migration and persistence of T cells in the tumor, which induce complete tumor regression and long-lasting immunologic memory in pre-clinical models of aggressive tumors such as glioblastoma, ovarian and pancreatic cancer.

/pdf/cxcr1-or-cxcr2-modified-car-t-cells-co-opt-il-8-for-maximal-447ebujkl0.pdf

CXCR1- or CXCR2-modified CAR T cells co-opt IL-8 for maximal antitumor efficacy in solid tumors

The heterogeneous expression of tumor-associated antigens limits the efficacy of chimeric antigen receptor (CAR)-redirected T cells (CAR-Ts) for the treatment of glioblastoma (GBM). We have found that chondroitin sulfate proteoglycan 4 (CSPG4) is highly expressed in 67% of the GBM specimens with limited heterogeneity. CSPG4 is also expressed on primary GBM-derived cells, grown in vitro as neurospheres (GBM-NS), which recapitulate the histopathology and molecular characteristics of primary GBM. CSPG4.CAR-Ts efficiently controlled the growth of GBM-NS in vitro and in vivo upon intracranial tumor inoculation. Moreover, CSPG4.CAR-Ts were also effective against GBM-NS with moderate to low expression of CSPG4. This effect was mediated by the in vivo up-regulation of CSPG4 on tumor cells, induced by tumor necrosis factor-α (TNFα) released by the microglia surrounding the tumor. Overall, the constitutive and TNFα-inducible expression of CSPG4 in GBM may greatly reduce the risk of tumor cell escape observed when targeted antigens are heterogeneously expressed on tumor cells.

/pdf/constitutive-and-tnfa-inducible-expression-of-chondroitin-f40b83p8cu.pdf

Constitutive and TNFα-inducible expression of chondroitin sulfate proteoglycan 4 in glioblastoma and neurospheres: Implications for CAR-T cell therapy

In the ex vivo stimulation method of dendritic cells, the stimulation occurs with the lysate of tumour spheres (TS) of the solid tumours.

Method for stimulating dendritic cells and cell product thus obtained for the autologous immunotherapy of solid human tumours

507. Chondroitin Sulfate Proteoglycan 4 (CSPG4)-Redirected T Cells Eliminate Glioblastoma-Derived Neurospheres

Two clinical studies, DENDR1 and DENDR2 including, respectively, the treatment of first diagnosis and recurrent glioblastoma (GB) patients with dendritic cells (DCs) loaded with autologous tumor lysate are currently active at Istituto Neurologico Besta, Milan. Our first results obtained on a group of recurrent GB patients demonstrated that the response of NK cells correlates with significantly prolonged survival. Here we provide results of the interim analysis on 22 patients affected by primary GB. Patients with post-surgery volume ≤10 cc underwent leukapheresis before radiotherapy and chemotherapy with temozolomide (TMZ). Three intradermal injections of mature DC were done before adjuvant chemotherapy. The subsequent 4 injections were performed 17 ± 3 days after adjuvant TMZ. MRI, clinical and immunological follow-up were performed every 2 months. The median age at surgery was 54.5 years (28-69). RT-TMZ induced significant lymphopenia ( 1000 lymphocytes/microl (5/22) before first vaccination had shorter PFS than others (p < 0.005). Peripheral Blood Lymphocytes (PBLs) were analyzed by flow cytometry to identify CD8+ T cells, NK and NKT cells before and after DC vaccines. The ratio of vaccination/baseline frequencies and counts (V/B ratio) of all of the immunological parameters for each patient was calculated, and the median of all of the observations used as the cut off value to separate patients. V/B ratio was correlated with the progression free survival (PFS) of each patient. Increased V/B ratio for NK cells and in particular NKT cells, but not for CD8 T lymphocytes, was significantly associated with prolonged PFS (median PFS 14 vs 8.0 mo, p = 0.01; 15.0 vs 8.0 mo, respectively). Interferon (IFN)-γ in PBLs was significantly higher in patients with PFS12 (p < 0.02), increasing immediately after the second vaccination as evaluated by real time-PCR. No changes in the expression levels of IFN-γ were observed in the other patients. After a median follow up of 14 months (6-27), the median progression-free survival (PFS) was 9 mo, with PFS6 90% (C. I. 0.78-1.029%) and PFS12 42% (C. I: 0.20-0.64) at Kaplan Meier analysis. Median overall survival (OS) was 22 mo with OS 12 70%. (C. I. 0.50-0.9). 2/4 patients with MGMT methylation were in the group of high V/B ratio. Our results show a positive association between increased peripheral NK and NKT cells response and prolonged survival. Further investigations are required on possible interference of radio-chemotherapy on activation of CD8+ T cells.

P02.03increased counts of nk and nkt cells are associated with prolonged survival in primary glioblastoma patients treated with dendritic cell immunotherapy in combination with radio- and chemo-therapy

S. Pellegatta

Papers

Constitutive and TNFα-inducible expression of chondroitin sulfate proteoglycan 4 in glioblastoma and neurospheres: Implications for CAR-T cell therapy

Method for stimulating dendritic cells and cell product thus obtained for the autologous immunotherapy of solid human tumours

507. Chondroitin Sulfate Proteoglycan 4 (CSPG4)-Redirected T Cells Eliminate Glioblastoma-Derived Neurospheres

P02.03increased counts of nk and nkt cells are associated with prolonged survival in primary glioblastoma patients treated with dendritic cell immunotherapy in combination with radio- and chemo-therapy

C URRENT OPINION Perspectives for immunotherapy in glioblastoma treatment