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The nanoparticle complex of cholesteryl pullulan (CHP) and NY-ESO-1 antigen protein (CHP-NY-ESO-1) presents multiple epitope peptides to MHC class I and II pathways, leading to CD8+ and CD4+ T cell responses. Poly-ICLC is a synthetic, double-stranded RNA, an agonist of toll-like receptor (TLR)-3, and a cytoplasmic receptor of melanoma differentiation-associated gene (MDA)-5. It should be a suitable immune adjuvant of cancer vaccine to overcome the inhibitory tumor microenvironment. We conducted a phase 1 clinical trial of CHP-NY-ESO-1 with poly-ICLC in patients with advanced or recurrent esophageal cancer. CHP-NY-ESO-1/poly-ICLC (μg/mg) was administered at a dose of 200/0.5 or 200/1.0 (cohorts 1 and 2, respectively) every 2 weeks for a total of six doses. The primary endpoints were safety and immune response. The secondary endpoint was tumor response. In total, 16 patients were enrolled, and six patients in each cohort completed the trial. The most common adverse event (AE) was injection site skin reaction (86.7%). No grade 3 or higher drug-related AEs were observed. No tumor responses were observed, and three patients (30%) had stable disease. The immune response was comparable between the two cohorts, and all patients (100%) achieved antibody responses with a median of 2.5 vaccinations. Comparing CHP-NY-ESO-1 alone to the poly-ICLC combination, all patients in both groups exhibited antibody responses, but the titers were higher in the combination group. In a mouse model, adding anti-PD-1 antibody to the combination of CHP-NY-ESO-1/poly-ICLC suppressed the growth of NY-ESO-1-expressing tumors. Combining the vaccine with PD-1 blockade holds promise in human trials.

Polyfunctionality/multifunctionality of effector T cells at the single cell level has been shown as an important parameter to predict the quality of T cell response and immunological control of infectious disease and malignancy. However, the fate of polyfunctional CD8+ CTLs and the factors that control the polyfunctionality of T cells remain largely unknown. Here we show that the acquisition of polyfunctionality on the initial stimulation is a sensitive immune correlate of CTL survival and memory formation. CD8+ T cells with high polyfunctionality, assessed with γ‐interferon and tumor necrosis factor‐α production and surface mobilization of the degranulation marker CD107a, showed enhanced Bcl‐2 expression, low apoptosis, and increased CD127highKLRG1low memory precursor phenotype. Consistent with these observations, CD8+ T cells were found to acquire high frequency of cells with polyfunctionality when stimulated in conditions known to enhance memory formation, such as the presence of CD4+ T cells, interleukin (IL)‐2, or IL‐21. Utilizing T‐cell receptor (TCR) transgenic mouse‐derived CD8+ T cells that express a TCR specific for a tumor‐derived neoantigen, we showed that polyfunctional tumor‐specific CTLs generated in the presence of CD4+ T cells showed long persistence in vivo and induced enhanced tumor regression when adoptively transferred into mice with progressing tumor. Acquisition of polyfunctionality thus impacts CTL survival and memory formation associated with immunological control of tumor., We report that polyfunctional CD8+ T cells showed the potential for long survival and memory formation. We found that CD4+ T cells, interleukin (IL)‐2, and IL‐21 exert a critical effect on the determination of polyfunctionality of CD8+ T cells. Polyfunctional tumor‐specific CTLs generated in the presence of CD4+ T cells showed long persistence in vivo and induced enhanced tumor regression when used for adoptive immunotherapy.

Cholesteryl pullulan (CHP) is a novel antigen delivery system. CHP and New York esophageal squamous cell carcinoma 1 (NY-ESO-1) antigen complexes (CHP-NY-ESO-1) present multiple epitope peptides to the MHC class I and II pathways. Adjuvants are essential for cancer vaccines. MIS416 is a non-toxic microparticle that activates immunity via the nucleotide-binding oligomerization domain 2 (NOD2) and TLR9 pathways. However, no reports have explored MIS416 as a cancer vaccine adjuvant. We conducted a first-in-human clinical trial of CHP-NY-ESO-1 with MIS416 in patients with NY-ESO-1-expressing refractory solid tumors. CHP-NY-ESO-1/MIS416 (μg/μg) was administered at 100/200, 200/200, 200/400 or 200/600 (cohorts 1, 2, 3 and 4, respectively) every 2 weeks for a total of 6 doses (treatment phase) followed by one vaccination every 4 weeks until disease progression or unacceptable toxicity (maintenance phase). The primary endpoints were safety and tolerability, and the secondary endpoint was the immune response. In total, 26 patients were enrolled. Seven patients (38%) continued vaccination in the maintenance phase. Grade 3 drug-related adverse events (AEs) were observed in six patients (23%): anorexia and hypertension were observed in one and five patients, respectively. No grade 4–5 drug-related AEs were observed. Eight patients (31%) had stable disease (SD). Neither augmentation of the NY-ESO-1-specific IFN-γ-secreting CD8+ T cell response nor an increase in the level of anti-NY-ESO-1 IgG1 was observed as the dose of MIS416 was increased. In a preclinical study, adding anti-PD-1 monoclonal antibody to CHP-NY-ESO-1 and MIS416 induced significant tumor suppression. This combination therapy is a promising next step. Electronic supplementary material The online version of this article (10.1007/s00262-020-02483-1) contains supplementary material, which is available to authorized users.

The anti-tumor efficacy of TCR-engineered T cells in vivo depends largely on less-differentiated subsets such as T cells with naive-like T cell (TN) phenotypes with greater expansion and long-term persistence. To increase these subsets, we compared the generation of New York esophageal squamous cell carcinoma-1 (NY-ESO-1)-specific T cells under supplementation with either IL-2 or IL-7/IL-15. PBMCs were transduced with MS3II-NY-ESO-1-siTCR retroviral vector. T cell generation was adapted from a CD19-specific CART cell production protocol. Comparable results in viability, expansion and transduction efficiency of T cells under stimulation with either IL-2 or IL-7/IL-15 were observed. IL-7/IL-15 led to an increase of CD4+ T cells and a decrease of CD8+ T cells, enriched the amount of TN among CD4+ T cells but not among CD8+ T cells. In a 51Cr release assay, similar specific lysis of NY-ESO-1-positive SW982 sarcoma cells was achieved. However, intracellular cytokine staining revealed a significantly increased production of IFN-γ and TNF-α in T cells generated by IL-2 stimulation. To validate these unexpected findings, NY-ESO-1-specific T cell production was evaluated in another protocol originally established for TCR-engineered T cells. IL-7/IL-15 increased the proportion of TN. However, the absolute number of TN did not increase due to a significantly slower expansion of T cells with IL-7/IL-15. In conclusion, IL-7/IL-15 does not seem to be superior to IL-2 for the generation of NY-ESO-1-specific T cells. This is in sharp contrast to the observations in CD19-specific CART cells. Changes of cytokine cocktails should be carefully evaluated for individual vector systems.

Immune checkpoint inhibitors and adoptive transfer of gene-engineered T cells have emerged as novel therapeutic modalities for hard-to-treat solid tumors; however, many patients are refractory to these immunotherapies, and the mechanisms underlying tumor immune resistance have not been fully elucidated. By comparing the tumor microenvironment of checkpoint inhibition-sensitive and -resistant murine solid tumors, we observed that the resistant tumors had low immunogenicity. We identified antigen presentation by CD11b+F4/80+ tumor-associated macrophages (TAMs) as a key factor correlated with immune resistance. In the resistant tumors, TAMs remained inactive and did not exert antigen-presenting activity. Targeted delivery of a long peptide antigen to TAMs by using a nano-sized hydrogel (nanogel) in the presence of a TLR agonist activated TAMs, induced their antigen-presenting activity, and thereby transformed the resistant tumors into tumors sensitive to adaptive immune responses such as adoptive transfer of tumor-specific T cell receptor-engineered T cells. These results indicate that the status and function of TAMs have a significant impact on tumor immune sensitivity and that manipulation of TAM functions would be an effective approach for improving the efficacy of immunotherapies., The Journal of clinical investigation, 129(3), pp.1278-1294; 2019

Introduction: Cytokine release syndrome (CRS) is a potentially life-threatening systemic disease that has been observed after treatment with antibodies and adoptive T cell therapies. In this case, we observed nivolumab-induced CRS in a patient with gastric cancer. Case Presentation: A 43-year-old male with advanced gastric cancer was treated with nivolumab as a third-line chemotherapy. He had no history of allergies. Eight days after the first administration of nivolumab, fever, tachycardia, appetite loss and increases in liver and biliary enzymes were observed. Computed tomography revealed neither bile duct obstruction nor progression of liver metastases but showed that there was edema of the Gleason sheath. Histopathological analysis of the liver revealed cholestatic liver injury with CD8+ T lymphocyte and macrophage infiltration. Neither viral infection nor autoimmune disease was revealed. His symptoms were similar to those of CRS observed after T cell therapy. We diagnosed his disease as nivolumab-induced liver injury and cholangitis accompanied by CRS based on his serum cytokine levels. Discussion/Conclusion: To the best of our knowledge, this is the first report of nivolumab-induced CRS in a patient with gastric cancer.

Exosomes secreted from T cells have been shown to affect dendritic cells, cancer cells, and other T cells. However, little is known about how T-cell exosomes (T exosomes) modulate endothelial cell functions in the context of tissue-specific homing. Here, we study the roles of T exosomes in the regulation of gut-specific T-cell homing. The gut-tropic T cells induced by retinoic acid secrete the exosomes that upregulate integrin α4β7 binding to the MAdCAM-1 expressed on high endothelial venules in the gut. T exosomes were preferentially distributed to the villi of the small intestine in an α4β7-dependent manner. Exosomes from gut-tropic T cells suppressed the expression of MAdCAM-1 in the small intestine, thereby inhibiting T-cell homing to the gut. Moreover, microRNA (miRNA) profiling analysis has shown that exosomes from gut-tropic T cells were enriched with miRNAs targeting NKX2.3, a transcription factor critical to MAdCAM-1 expression. Taken together, our study proposes that α4β7-expressing T exosomes distribute themselves to the small intestine and modify the expression of microenvironmental tissues such that any subsequent lymphocyte homing is precluded. This may represent a novel mechanism by which excessive lymphocyte homing to the intestinal tissues is downsized.

Background Adoptive immunotherapy using chimeric antigen receptor (CAR) is recently reported as one of the effective cancer therapy. Especially CAR-T cell therapy targeting CD19 antigen in B-cell tumors have shown impressive clinical results and CAR-T cell products targeting CD19 have already approved. However as the high relapse rate is still the problem and the clinical efficacy of CAR-T cell therapy for solid tumors is currently inadequate, further improvement of CAR design is required.It is known that the design of CAR construct affects the function of CAR-T cells. For example co-stimulatory domain such as CD28 and 4-1BB is used in the second generation CARs, CD28z-CAR-T cells show higher anti-tumor activity, whereas 4-1BBz-CAR-T cells demonstrate superior in vivo persistence. To enhance survival of T cells, several attempts had been made to optimize the signaling domains. Recently, we have developed the novel CARs incorporated GITR (glucocorticoid-induced tumor necrosis factor receptor family-related protein) intracellular domain for T cell survival prolongation and inhibition of regulatory T cells’ suppressive activity. It is also reported that the antigen-nonspecific activation of CAR-T cells (tonic signaling) is influenced by the CAR design, and excessive T cell activation leads exhaustion of CAR-T cells. Previously, we have found that the design of CAR, not only single chain variable fragments (scFvs), affect the strength of tonic signaling. Thus, the optimization of CAR construct is essential to induce antigen-specific response with minimal non-specific activation, which results in maximal efficacy. Methods We have optimized the structure of anti-CEA-GITR-CAR targeting CEA antigen expressing solid tumor such as gastric and pancreatic cancer. We have constructed several CARs with the different composition such as hinge region, transmembrane domain, and the order of VL/VH in scFV region, and compared the tonic signaling and antigen-specific activity in CAR-T cells. Results The property of CAR-T cells was largely affected by the CAR constructs, especially the hinge region. The CAR-T cells with CD8α hinge showed strong tonic signaling, the CAR-T cells with short hinge-CAR lost antigen specificity, and elimination of hinge region lowered the CAR expression level and antigen reactivity. Furthermore, GITR-CAR-T cells showed higher proportion of CCR7+CD45RA+ cells and lower expression of exhaustion markers (PD1, Tim3, and LAG3) compared to CD28z-CAR-T cells. Conclusions Our CEA-GITR-CAR with the optimized scFV design and CD28-hinge demonstrated improved antigen-specific response with reduced tonic signaling, potentially indicating that our novel CAR-T cells may show improved clinical efficacy on solid tumor.

Background Cancer testis (CT) antigens are promising targets for cancer immunotherapies such as cancer vaccines and genetically modified adoptive T cell therapy. In this study, we evaluated the expression of three CT antigens, melanoma-associated antigen A4 (MAGE-A4), New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) and sarcoma antigen gene (SAGE). Methods MAGE-A4, NY-ESO-1 and/or SAGE antigen expression in tumour samples was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Informed consent was obtained from individuals prior to study enrolment. Results In total, 585 samples in 21 tumour types were evaluated between June 2009 and March 2018. The positive expression rates of these CT antigens were as follows: MAGE-A4, 34.6% (range, 30.7–38.7); NY-ESO-1, 21.0% (range, 17.2–25.1); and SAGE, 21.8% (range, 18.5–25.4). The MAGE-A4 antigen was expressed in 54.9% of oesophageal cancers, 37.5% of head and neck cancers, 35.0% of gastric cancers and 34.2% of ovarian cancers; the NY-ESO-1 antigen was expressed in 28.6% of lung cancers, 25.3% of oesophageal cancers and 22.6% of ovarian cancers; and the SAGE antigen was expressed in 35.3% of prostate cancers, 32.9% of oesophageal cancers and 26.3% of ovarian cancers. The most common tumour type in this study was oesophageal cancer. MAGE-A4, NY-ESO-1 and SAGE antigen expression were assessed in 214 oesophageal cancer samples, among which 24 (11.2%) were triple-positive, 58 (27.1%) were positive for any two, 59 (27.6%) were positive for any one, and 73 (34.1%) were triple negative. Conclusions Oesophageal cancer exhibited a relatively high rate of CT antigen mRNA expression positivity.

// Yasutaka Tono 1, 2 , Mikiya Ishihara 2 , Yoshihiro Miyahara 3 , Satoshi Tamaru 2 , Hiroyasu Oda 2 , Yoshiki Yamashita 2 , Isao Tawara 1 , Hiroaki Ikeda 3, 4 , Hiroshi Shiku 3 , Toshiro Mizuno 2 and Naoyuki Katayama 1, 2 1 Department of Hematology and Oncology, Mie University Graduate School of Medicine, 514-8507 Mie, Japan 2 Department of Medical Oncology, Mie University Hospital, 514-8507 Mie, Japan 3 Department of Immuno-Gene Therapy, Mie University Graduate School of Medicine, 514-8507 Mie, Japan 4 Department of Oncology, Nagasaki University Graduate School of Biomedical Sciences, 852-8523 Nagasaki, Japan Correspondence to: Mikiya Ishihara, email: mishihara@clin.medic.mie-u.ac.jp Keywords: breast cancer; eribulin mesylate; HER2-positive; trastuzumab; pertuzumab Received: May 09, 2017 Accepted: February 07, 2018 Epub: February 16, 2018 Published: March 13, 2018 ABSTRACT The standard treatment for advanced human epidermal growth factor receptor 2 (HER2)-positive breast cancer is the triple combination of pertuzumab, trastuzumab and docetaxel, but some patients cannot tolerate taxane. To explore a non-taxane triple therapy, we conducted a feasibility study of pertuzumab, trastuzumab and eribulin mesylate (PTE) therapy for previously treated advanced HER2-positive breast cancer with analyses of quality of life and biomarkers. Ten patients were enrolled, two of whom had a history of docetaxel allergy. The median number of prior regimens was 3. The most common Grade 3 toxicities were leukopenia (70%) and neutropenia (70%). Grade 4 or 5 adverse events were not observed. An improving trend for the Functional Assessment of Cancer Therapy-Breast (FACT-B) score at 3 months was observed. Eight cases were included in the biomarker analysis. The peripheral CD8+ T cell/ CD4+Foxp3+ regulatory T cells (Tregs) ratio was significantly increased ( p = 0.039). The frequency of peripheral Tregs was associated with the trastuzumab trough concentration ( p = 0.019). In a non-clinical analysis, Eribulin mesylate significantly inhibited Ser473 Akt phosphorylation in PIK3CA wild-type cells and mutated cells. These results suggest that PTE therapy is a feasible and promising option for advanced HER2-positive breast cancer. Further investigation is warranted.

Wilms' tumor 1 (WT1) is constantly expressed in leukemic cells of acute leukemia and myelodysplastic syndrome (MDS). A T-cell receptor (TCR) that specifically reacts with WT1 peptide in the context of HLA-A*24:02 has been identified. We conducted a first-in-human trial of TCR-gene transduced T-cell (TCR-T-cell) transfer in patients with refractory acute myeloblastic leukemia (AML) and high-risk MDS to investigate the safety and cell kinetics of the T cells. The WT1-specific TCR-gene was transduced to T cells using a retroviral vector encoding small interfering RNAs for endogenous TCR genes. The T cells were transferred twice with a 4-week interval in a dose-escalating design. After the second transfer, sequential WT1 peptide vaccines were given. Eight patients, divided into 2 dose cohorts, received cell transfer. No adverse events of normal tissue were seen. The TCR-T cells were detected in peripheral blood for 8 weeks at levels proportional to the dose administered, and in 5 patients, they persisted throughout the study period. The persisting cells maintained ex vivo peptide-specific immune reactivity. Two patients showed transient decreases in blast counts in bone marrow, which was associated with recovery of hematopoiesis. Four of 5 patients who had persistent T cells at the end of the study survived more than 12 months. These results suggest WT1-specific TCR-T cells manipulated by ex vivo culture of polyclonal peripheral lymphocytes survived in vivo and retained the capacity to mount an immune reaction to WT1. This trial was registered at www.umin.ac.jp as #UMIN000011519.

To harvest for T cell therapy, a 1.6-fold higher number of CD3+ T cells was collected with MNC mode (N = 10) compared with Auto PBSC mode (N = 5) in COBE Spectra cell separator, but the blood product volume was increased by 3.5-fold. For therapeutic angiogenesis therapy, apheresis was initially performed using Auto PBSC mode (N = 4) to fine tune the blood product volume to omit cell concentration, but the collected number of mononuclear cells was lower than expected. However, an increase of the harvest cycle number from 3.8 ± 0.5 to 7.4 ± 2.0 cycles (N = 19) resulted in a 2.1-fold higher number of collected mononuclear cells (8.7 ± 4.1 × 109 vs. 4.1 ± 1.0 × 109 cells, P

// Daisuke Muraoka 1,2 , Naohiro Seo 1 , Tae Hayashi 1 , Chisaki Hyuga-Amaike 1 , Kana Okamori 1 , Isao Tawara 3 , Naozumi Harada 1 and Hiroshi Shiku 1 1 Department of Immuno-Gene Therapy, Mie University Graduate School of Medicine, Mie, Japan 2 Center for Drug Discovery, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan 3 Department of Hematology and Oncology, Mie University Graduate School of Medicine, Mie, Japan Correspondence to: Daisuke Muraoka, email: // Hiroshi Shiku, email: // Keywords : memory T cell, CTL function, STAP2, STAT signaling, SOCS3, Immunology and Microbiology Section, Immune response, Immunity Received : April 18, 2016 Accepted : February 01, 2017 Published : February 16, 2017 Abstract Long-surviving memory CD8 + T cells generated by stimulation with appropriate tumor-associated antigens are the most aggressive and persistent tumoricidal effectors. In this event of memory CD8 + T cell development, the signal transducer and activator of transcription (STAT) proteins function as the crucial intracellular signaling molecules, but the regulatory mechanism of STATs in CD8 + T cells is not fully understood. In this study, we report for the first time, by using murine vaccination models, that signal-transducing adaptor protein-2 (STAP2) maintains the cytotoxicity of long-lived memory CD8 + T cells by controlling a STAT3/suppressor of cytokine signaling 3 (SOCS3) cascade. Following T cell activation, STAP2 expression was transiently reduced but was subsequently recovered and augmented. Analysis using small-interfering RNA (siRNA) demonstrated that restored STAP2 expression was associated with the activation of STAT3/SOCS3 signals and maintenance of cytotoxic T lymphocytes (CTLs) secondary responses by preventing their differentiation into terminal effector cells. Notably, this STAP2-dependent memory differentiation was observed in the spleen, but not in the lymph nodes (LNs). These findings indicate an essential role for STAP2 in the generation of a high-quality memory CD8 + CTLs periphery, and suggest the therapeutic potential of STAP2 in cancer patients.

A phase I+II clinical trial of vaccination with MAGE-A4 protein complexed with cholesteryl pullulan melanoma antigen gene-A4 nanogel (CHP-MAGE-A4) is currently underway in patients with MAGE-A4-expressing cancer. In the present study, the primary phase I endpoint was to test the safety of the administration of 300 µg CHP-MAGE-A4 with and without OK-432. Another aim of the study was to clarify the details of the specific humoral immune response to vaccination. The 9 patients enrolled for phase I were vaccinated 6 times, once every 2 weeks: 3 patients with 100 µg and 3 patients with 300 µg CHP-MAGE-A4, and 3 patients with 300 µg CHP-MAGE-A4 plus 0.5 clinical units of OK-432. Toxicities were assessed using Common Terminology Criteria for Adverse Events v3.0. Clinical response was evaluated by modified Response Evaluation Criteria in Solid Tumours. Immunological monitoring of anti-MAGE-A4-specific antibodies was performed by ELISA of pre- and post-vaccination patient sera. The 6 vaccinations produced no severe adverse events. Stable disease was assessed in 4/9 patients. Anti-MAGE-A4 total immunoglobulin (Ig)G titers increased in 7/9 patients. Efficacious anti-MAGE-A4 IgG1, 2 and 3 antibody responses were observed in 7/9 patients. Among them, positive conversions to T helper 2 (Th2)-type antibody responses (IgG4 and IgE) were observed after frequent vaccination in 4/7 patients. The Th2 conversion was possibly associated with undesirable clinical observations, including progressive disease and the appearance of a new relapse lesion. The present study suggested that frequent vaccinations activated a Th2-dominant status in the cancer patients. The identification of a time-dependent IgG subclass and IgE antibody production during vaccination protocols may be a useful surrogate marker indicating a potentially undesirable change of the immunological environment for an effective antitumor immune response in cancer patients.

Adoptive T cell therapy using tumor-specific T cells or TCR-modified T cells is a promising next-generation immunotherapy. The major source of tumor-reactive T cells is PD-1+ tumor-infiltrating lymphocytes (TILs). In contrast, PD-1- TILs have received little attention. Here, we analyzed the TCR-β repertoires of PD-1- and PD-1+ CD8+ TILs derived from colorectal cancer and breast cancer. Approximately 40-60% of the PD-1+ population consisted of oligoclonal populations in both colorectal cancer and breast cancer. In contrast, approximately 37% of the PD-1- population consisted of an oligoclonal population in colorectal cancer, whereas 14% of them were oligoclonal in breast cancer. In colorectal cancer, the TCR repertoires of PD-1- CD8+ TILs and PD-1+ CD8+ TILs hardly overlapped. Interestingly, clonally expanded CD8+ TILs in primary tumors and the metastases expressing the same clonotypic TCR showed the same phenotype regarding the PD-1-expression. These results suggest that the intrinsic properties of TCRs determine the fate of TILs in terms of whether they become PD-1+ or PD-1- in the tumor microenvironment. Further functional analysis of TCRs in TILs will allow us to better understand the regulatory mechanisms for PD-1 expression on TILs and may contribute to tumor immunotherapy.

The aim of the present study was to explore the expression of the cancer testis antigens New York-esophageal squamous cell carcinoma (NY-ESO)-1 and melanoma-associated antigen (MAGE)-A4 in high-grade soft-tissue sarcoma and to evaluate their association with the standard clinical-pathological features of surgically treated high-grade sarcoma patients. The study included 82 patients, and NY-ESO-1 and MAGE-A4 antigen expression was analyzed immunohistochemically. The results revealed NY-ESO-1- and MAGE-A4-positive staining in 58.8 and 52.9% of synovial sarcomas, and 55.6 and 0% of myxoid liposarcomas, respectively. In patients with synovial sarcoma, NY-ESO-1 and MAGE-A4 were expressed in 7 patients, only NY-ESO-1 was expressed in 3 patients, and only MAGE-A4 was expressed in 2 patients. Univariate analysis indicated that a significantly higher MAGE-A4 expression was observed in younger patients (P

NY-ESO-1-specific T cells have shown promising activity in the treatment of soft tissue sarcoma (STS). However, standardized protocols for their generation are limited. Particularly, cost-effectiveness considerations of cell production protocols are of importance for conducting clinical studies. In this study, two different NY-ESO-1-specific T cell production protocols were compared. Major differences between protocols 1 and 2 include culture medium, interleukin-2 and retronectin concentrations, T cell activation strategy, and the transduction process. NY-ESO-1-specific T cells generated according to the two protocols were investigated for differences in cell viability, transduction efficiency, T cell expansion, immunophenotype as well as functionality. NY-ESO-1-specific T cells showed similar viability and transduction efficiency between both protocols. Protocol 1 generated higher absolute numbers of NY-ESO-1-specific T cells. However, there was no difference in absolute numbers of NY-ESO-1-specific T cell subsets with less-differentiated phenotypes accounting for efficient in vivo expansion and engraftment. Furthermore, cells generated according to protocol 1 displayed higher capacity of TNF-&alpha, generation, but lower cytotoxic capacities. Overall, both protocols provided functional NY-ESO-1-specific T cells. However, compared to protocol 1, protocol 2 is advantageous in terms of cost-effectiveness. Cell production protocols should be designed diligently to achieve a cost-effective cellular product for further clinical evaluation.

Purpose: Mogamulizumab (Mog), a humanized anti-CC chemokine receptor 4 (CCR4) mAb that mediates antibody-dependent cellular cytotoxicity (ADCC) using FcγR IIIa (CD16)-expressing effector cells, has recently been approved for treatment of CCR4-positive adult T-cell leukemia (ATL) in Japan. However, Mog failure has sometimes been observed in patients who have accompanying chemotherapy-associated lymphocytopenia. In this study, we examined whether adoptive transfer of artificial ADCC effector cells combined with Mog would overcome this drawback. Experimental Design: We lentivirally gene-modified peripheral blood T cells from healthy volunteers and ATL patients expressing the affinity-increased chimeric CD16-CD3ζ receptor (cCD16ζ-T cells). Subsequently, we examined the ADCC effect mediated by those cCD16ζ-T cells in the presence of Mog against ATL tumor cells both in vitro and in vivo. Results: cCD16ζ-T cells derived from healthy donors killed in vitro Mog-opsonized ATL cell line cells (n = 7) and primary ATL cells (n = 4) depending on both the number of effector cells and the dose of the antibody. cCD16ζ-T cells generated from ATL patients (n = 3) also exerted cytocidal activity in vitro against Mog-opsonized autologous ATL cells. Using both intravenously disseminated model (n = 5) and subcutaneously inoculated model (n = 4), coadministration of Mog and human cCD16ζ-T cells successfully suppressed tumor growth in xenografted immunodeficient mice, and significantly prolonged their survival (P < 0.01 and P = 0.02, respectively). Conclusions: These data strongly suggest clinical feasibility of the novel combined adoptive immunotherapy using cCD16ζ-T cells and Mog for treatment of aggressive ATL, particularly in patients who are ineligible for allogeneic hematopoietic stem cell transplantation. Clin Cancer Res; 22(17); 4405–16. ©2016 AACR.

Aim: To investigate the antigen spreading pattern in the CHP-MAGE-A4-vaccinated patients and analyze the clinical relevance of antigen spreading pattern as a surrogate marker of patient survival. Materials & methods: 12 patients who had been injected with 300 μg of CHP-MAGE-A4 and 0.5 Klinische Einheit of OK-432 in more than five vaccinations were analyzed. Results: Increases in the anti-MAGE-A4-specific antibody response were observed in eight patients (66.7%), compared with six patients (50%) for anti-NY-ESO-1 and five patients (41.7%) for anti-MAGE-A3 after five vaccinations. We identified frequent antigen spreading following MAGE-A4 vaccinations without associations with the clinical response or patient prognosis. Conclusion: Antigen spreading pattern might reflect tumor shrinkage as a response to treatment and treatment history (clinical trial registration number: UMIN000001999).

MAGE-A4 antigen is a cancer-testis antigen that is frequently expressed in tumor tissues. Cholesteryl pullulan (CHP) is a novel antigen delivery system for cancer vaccines. This study evaluated the safety, immune responses and clinical outcomes of patients who received a CHP-MAGE-A4 vaccine. Twenty-two patients with advanced or metastatic cancer were enrolled, and were subcutaneously vaccinated with either 100 μg or 300 μg of CHP-MAGE-A4. Seven and 15 patients, respectively, were repeatedly vaccinated with 100 μg or 300 μg of CHP-MAGE-A4; patients in both groups received a median of 7 doses. No serious adverse events related to the vaccine were observed. Of 7 patients receiving the 100 μg dose, 2 (29%) showed immune responses, compared with 3 of the 14 (21%) patients who received the 300 μg dose. In total, MAGE-A4-specific antibody responses were induced in 5 of 21 (24%) patients. No differences in survival were seen between patients receiving the 100 μg and 300 μg doses, or between immune responders and non-responders. Eleven (50%) patients had pre-existing antibodies to NY-ESO-1. In 16 patients with esophageal or head/neck squamous cell carcinoma, the survival time was significantly shorter in those who had NY-ESO-1-co-expressing tumors. Patients with high pre-existing antibody responses to NY-ESO-1 displayed worse prognosis than those with no pre-existing response. Therefore, in planning clinical trials of MAGE-A4 vaccine, enrolling NY-ESO-1-expressing tumor or not would be a critical issue to be discussed. Combination vaccines of MAGE-A4 and NY-ESO-1 antigens would be one of the strategies to overcome the poor prognosis.

Background/aim The aim of this study was to explore whether the treatment effect or immune response to a cancer vaccine can be predicted by the percentage of CD4+CD25+Foxp3+ regulatory T cells (Tregs) in peripheral blood mononuclear cells (PBMCs) after vaccination. Patients and methods Sixteen patients (9 men, 7 women; median age 61.5 years) enrolled in the CHP-MAGE-A4 cancer vaccine clinical trial who had a fixed dose (300 μg of CHP-MAGE-A4 cancer vaccine and 0.5 Klinische Einheit (KE) of OK432 and received at least four vaccinations were investigated. Safety, immune response, and clinical effects were assessed before and after the cancer vaccination. Results Treg ratios that remained low both before and after vaccination were associated with a good prognosis, and a low Treg/CD4 lymphocyte ratio 7-weeks after the initial vaccination was correlated with a better prognosis. Conclusion The Treg ratio following vaccination appears to have some utility for predicting patient prognosis.

Melanoma antigen family A4 (MAGEA4), a cancer/testis antigen, is overexpressed and is thus an immunotherapy target in various malignant tumors, including non-small cell lung cancer. However, whether MAGEA4 induces or inhibits the apoptosis of lung cancer cells remains controversial, as is its prognostic significance, particularly since there is no reliable method with which to detect MAGEA4 specifically. In this study, we optimized assay conditions to detect MAGEA4 based on cells transiently transfected with MAGEA genes, and found that MAGEA4 was expressed in four of eight non-small cell lung cancer cell lines, and in 25.4% of clinical lung cancer specimens. We also found that MAGEA4 overexpression decreased apoptosis, as measured by the levels of cleaved caspase-3 in stably transfected 293F cells. Notably, patients with nuclear MAGEA4, but not p53 expression exhibited a significantly poorer survival than those expressing both nuclear MAGEA4 and p53. Indeed, multivariate analysis identified nuclear MAGEA4 as an independent prognostic factor (P=0.0042), albeit only in the absence of p53. In this study, to the best of our knowledge, we are the first to demonstrate that the function and prognostic value of MAGEA4 depends on its subcellular localization and on the p53 status.

The recent success of chimeric antigen receptor (CAR)-T cell therapy for treatment of hematologic malignancies supports further development of treatments for both liquid and solid tumors. However, expansion of CAR-T cell therapy is limited by the availability of surface antigens specific for the tumor while sparing normal cells. There is a rich diversity of tumor antigens from intracellularly expressed proteins that current and conventional CAR-T cells are unable to target. Furthermore, adoptively transferred T cells often suffer from exhaustion and insufficient expansion, in part, because of the immunosuppressive mechanisms operating in tumor-bearing hosts. Therefore, it is necessary to develop means to further activate and expand those CAR-T cells in vivo. The Wilms tumor 1 (WT1) is an intracellular oncogenic transcription factor that is an attractive target for cancer immunotherapy because of its overexpression in a wide range of leukemias and solid tumors, and a low level of expression in normal adult tissues. In the present study, we developed CAR-T cells consisting of a single chain variable fragment (scFv) specific to the WT1235-243/HLA-A*2402 complex. The therapeutic efficacy of our CAR-T cells was demonstrated in a xenograft model, which was further enhanced by vaccination with dendritic cells (DCs) loaded with the corresponding antigen. This enhanced efficacy was mediated, at least partly, by the expansion and activation of CAR-T cells. CAR-T cells shown in the present study not only demonstrate the potential to expand the range of targets available to CAR-T cells, but also provide a proof of concept that efficacy of CAR-T cells targeting peptide/major histocompatibility complex can be boosted by vaccination.

The CXCR3 ligands CXCL9, 10, and 11 play critical roles in the amplification of immune responses by recruiting CXCR3+ immune effector cells to the tumor site. Taking advantage of this property of CXCR3 ligands, we aimed to establish a novel approach to identify immunogenic mutated-antigens. We examined the feasibility of using CXCR3 ligand mRNAs as sensors for detection of specific immune responses in human and murine systems. We further investigated whether this approach is applicable for the identification of immunogenic mutated-antigens by using murine sarcoma lines. Rapid synthesis of CXCR3 ligand mRNAs occurred shortly after specific immune responses in both human and murine immune systems. Particularly, in CMS5 tumor-bearing mice, we detected specific immune responses to mutated mitogen-activated protein kinase 2 (ERK2), which has previously been identified as an immunogenic mutated-antigen. Furthermore, by combining this approach with whole-exome and transcriptome sequencing analyses, we identified an immunogenic neo-epitope derived from mutated staphylococcal nuclease domain-containing protein 1 (Snd1) in CMS7 tumor-bearing mice. Most importantly, we successfully detected the specific immune response to this neo-epitope even without co-administration of anti-cytotoxic T-lymphocyte protein-4 (CTLA-4), anti-programmed cell death-1 (PD-1) and anti-glucocorticoid-induced TNFR-related protein (GITR) antibodies, which vigorously augmented the immune response and consequently enabled us to detect the specific immune response to this neo-epitope by conventional IFNγ intracellular staining method. Our data indicate the potential usefulness of this strategy for the identification of immunogenic mutated-antigens. We propose that this approach would be of great help for the development of personalized cancer vaccine therapies in future.

Purpose We conducted a cancer vaccine clinical trial with MAGE-A4 protein. Safety, clinical response, and antigen-specific immune responses were analyzed and the prognostic factors by vaccination were investigated. Experimental design Twenty patients with advanced esophageal, stomach or lung cancer were administered MAGE-A4 vaccine containing 300 μg protein subcutaneously once every 2 weeks in six doses. Primary endpoints of this study were safety and MAGE-A4 immune responses. Results The vaccine was well tolerated. Fifteen of 20 patients completed one cycle of vaccination and two patients showed SD. A MAGE-A4-specific humoral immune response was observed in four patients who had high expression of MAGE-A4 and MHC class I on tumor cells. These four patients showed significantly longer overall survival than patients without an antibody response after vaccination (p = 0.009). Patients with tumor cells expressing high MAGE-A4 or MHC class I antigen showed significantly longer overall survival than those with low expression. Induction of CD4 and CD8T cell responses was observed in three and six patients, respectively, and patients with induction of MAGE-A4-specific IFNγ-producing CD8T cells, but not CD4T cells, lived longer than those without induction. Conclusions The CHP-MAGE-A4 vaccine was safe. Expression of MAGE-A4 and MHC class I in tumor tissue and the induction of a MAGE-A4-specific immune response after vaccination would be feasible prognostic markers for patients vaccinated with MAGE-A4.

Because existing therapeutic cancer vaccines provide only a limited clinical benefit, a different vaccination strategy is necessary to improve vaccine efficacy. We developed a nanoparticulate cancer vaccine by encapsulating a synthetic long peptide antigen within an immunologically inert nanoparticulate hydrogel (nanogel) of cholesteryl pullulan (CHP). After subcutaneous injection to mice, the nanogel-based vaccine was efficiently transported to the draining lymph node, and was preferentially engulfed by medullary macrophages but was not sensed by other macrophages and dendritic cells (so-called "immunologically stealth mode"). Although the function of medullary macrophages in T cell immunity has been unexplored so far, these macrophages effectively cross-primed the vaccine-specific CD8(+) T cells in the presence of a Toll-like receptor (TLR) agonist as an adjuvant. The nanogel-based vaccine significantly inhibited in vivo tumor growth in the prophylactic and therapeutic settings, compared to another vaccine formulation using a conventional delivery system, incomplete Freund's adjuvant. We also revealed that lymph node macrophages were highly responsive to TLR stimulation, which may underlie the potency of the macrophage-oriented, nanogel-based vaccine. These results indicate that targeting medullary macrophages using the immunologically stealth nanoparticulate delivery system is an effective vaccine strategy.

Background: Adult T-cell leukemia/lymphoma (ATL) is a refractory peripheral T-cell malignancy caused by human T-lymphotropic virus type 1 (HTLV-1) infection. Although only allogeneic hematopoietic stem cell transplantation (allo-HSCT) displaying the graft-vs. ATL (GvATL) can bring durable remission, allo-HSCT is largely ineligible for newly diagnosed ATL patients due to disease aggressiveness and advanced age-related conditions. Thus, a novel treatment with safety and efficacy instead of allo-HSCT still remains an unmet need, and a cellular immunotherapy using TCR or CAR gene-modified immune cells exerting GvATL could be such an option. However, to generate those effector cells from autologous T cells of heavily pre-treated ATL patients faces many obstacles. To circumvent those hurdles, an employment of unconventional allogeneic Vγ9/δ2-T cells which are potentially free from the risk of GVHD could provide greater treatment opportunity for ATL patients due to highly extended donor availability. Taking above, here, we have newly devised an adoptive immunotherapy using a novel HTLV-1 p40Tax-specific TCR gene-modified allogeneic Vγ9/δ2 T cells against ATL. Methods: After written informed conscent, we firstly established novel HLA-A24 restricted TCR-α/β genes from HTLV-1 P40Tax301-309 (SFHSLHLLF)/HLA-A24 tetramer-positive peripheral CD8+T-lymphocytes of ATL patinets in durable remission using a single cell cloning method. Then, we confirmed that T cells gene-modified with these TCR-α/β genes exerted the epitope-specific and HLA-A24-restricted responses. Next, in order to achieve highly stable expression of this TCR-α/β heterodimer on gene-modified Vγ9/δ2-T cells, we newly developed a retroviral vector co-expressing TCR-α/β and CD8 α/β genes using self-cleaving P2A and E2A peptides. Using this vector, allogeneic Vγ9/δ2-T cells from healthy donors numerously expanded with high purity in our novel culture system were subjected to gene-transfer to express relevant TCR α/β complex. Thereafter, we asssessed target-reactive cytokine production and cytocidal activity mediated by those gene-modified allogeneic Vγ9/δ2-T cells both in vitro and in vivo. Finally, we additionally assessed a potential risk of GVHD using intravenous administration of another TCR gene-modified Vγ9/δ2 T-cells in vivo. Results: To start with PBMCs from healthy donors, allogeneic Vγ9/δ2-T cells were stably multiplied greater than thousandfold with a quite high purity (≥95%) using our novel bisphosphonate derivative PTA (tetrakis-pivaloyloxymethyl2-(thiazole-2-ylamino) ethylidene-1,1-bisphosphonate) combined with both 25 ng/ml of IL-7 and IL-15 in culture for 8 to 10 days. The stable expression of introduced TCR α/β heterodimer on Vγ9/δ2-T cells were successfully achieved by co-expression of CD8 α/β molecule. Those gene-modified Vγ9/δ2-T cells successfully recognized target peptide (SFHSLHLLF) in an HLA-A24 restricted fashion, and similarly demonstrated a cytocidal activity both in vitro and in vivo against HLA-A24 positive HTLV-1 infected cell lines (TL-Su and ILT#Hod), but not HLA-A24-negtive/Tax-positive cell line ILT#37 or HLA-A24-positve/Tax-negative cell line ATN-1. Furthermore, intravenously administered those TCR gene-modified Vγ9/δ2-T cells quickly and durably eradicated luciferase-gene modified TL-Su cells, but not ATN-1 cells in xenografted immunodeficient (NOG) mice, examined by in vivo imaging system. Finally, infused HLA-A2 restricted and NY-ESO-1 specific TCR (G50) gene-modified Vγ9/δ2-T cells exerted durable antitumor activity without causing GVHD using NOG mice xenografted with HLA-A2 positive melanoma cell line cells (NW-MEL-38). Conclusions: Our preclinical observations here obviously demonstrated the potential utility of TCR-α/β gene-modified allogeneic Vγ9/δ2-T cells for the treatment of ATL without causing GVHD. Further studies regarding biological behaviors of HTLV-1 Tax specific TCR-α/β gene-modified allogeneic Vγ9/δ2-T cells following target recognition in vivo are warranted, however, based on these lines of evidence and currently conducting assessments using clinical samples, we are planning to launch a novel clinical trial, particularly focusing on the applicability of HLA partially matched relative donors, as the source of gene-modified allogeneic Vγ9/δ2-T cells, which could highly extend the donor availability. Disclosures Fujiwara: BrightPath Biotherapeutics, Co.,Ltd.: Other: member of the department endowed by BrightPath Bio. Okumura:BrightPath Biotherapeutics, Co.,Ltd.: Other: member of the department endowed by BrightPth Bio.. Miyahara:BirghtPath Biotherapeutics, Co., Ltd.: Other: member of the department endowed by BrightPath Bio.. Wan:BrightPath Biotherapeutics, Co., Ltd.: Other: member of the department endowed by BrightPath Bio.. Tawara:Astellas Pharma: Research Funding; Ono Pharmaceutical: Research Funding; Kyowa Hakko Kirin: Honoraria, Research Funding. Shiku:BrightPath Biotherapeutics, Co., Ltd.: Other: Chair of the department endowed by BrightPath Bio..

Background Adoptive transfer of TCR-redirected T cells has been reported to exhibit efficacy in some patients with melanoma and sarcoma. However, cytokine release syndrome (CRS) or its relations to tumor response has not been well documented. This study aimed to evaluate clinical responses in association with the cell kinetics and CRSs after transfer of high-affinity NY-ESO-1 TCR-gene transduced T cells in cancer patients. Methods We developed a novel-type affinity-enhanced NY-ESO-1-specific TCR and an originally-developed retrovirus vector that encodes siRNA to silence endogenous TCR creation. The NY-ESO-1/TCR sequence was mutated for high affinity with replacements of G50A and A51E in CDR2 region. This is a first-in-human clinical trial of the novel NY-ESO-1-specfic TCR-T cell transfer to evaluate the safety, in vivo cell kinetics and clinical responses. It was designed as a cell-dose escalation from 5 x108 to 5 x109 cells. NY-ESO-1-expressing refractory cancer patients were enrolled, with 3 + 3 cohort design. Cyclophosphamide (1,500mg/m2) were administered prior to the TCR-T cell transfer as pre-conditioning. Results Nine patients were treated with the TCR-T cells that expanded in peripheral blood with a dose-dependent manner, associated with rapid proliferation within 5 days after infusion. Three patients receiving 5x109 cells developed early-onset CRSs, with elevated levels of serum IL-6, IFN-γ. The CRSs on day1 or 2 were well managed with tocilizumab treatment. Three synovial sarcoma patients exhibited tumor shrinkage and partial responses, and they all had high-expression of NY-ESO-1 in the tumor samples, namely, 75% or more. Exploratory analysis revealed that multiple chemotactic cytokines including CCL2 and CCL7, and IL-3 increased in the serum from the patients with CRS. The proportions of effector-memory phenotype T cells in the infused cell-product were significantly associated with CRS development. Conclusions The affinity-enhanced NY-ESO-1/TCR-T cell transfer exhibited early-onset CRS in association with in vivo cell proliferation and sequential tumor responses in the patients with high-NY-ESO-1-expressing synovial sarcoma. Clinical trial identification NCT02366546. Legal entity responsible for the study The authors. Funding Japan Agency for Medical Research and Development. Disclosure All authors have declared no conflicts of interest.

Background Since PD-1/PD-L1 blockade has displayed clinical efficacy in esophageal cancer patients, an immunological therapeutic approach such as a cancer vaccine will be realistic in clinics. NY-ESO-1, one of cancer-testis antigens, is expressed in approximately 30% esophageal squamous cell carcinoma (ESCC). Cholesteryl pullulan (CHP) is an antigen delivery system to antigen-presenting cells including macrophages. The complex of CHP and NY-ESO-1 protein (CHP-NY-ESO-1) is a vaccine that activates CD4+ and CD8+ T cells. We aimed to evaluate clinical efficacy of the CHP-NY-ESO-1 for esophageal cancer patients after radical surgery in a randomized phase II trial. Methods 54 NY-ESO-1-expressing ESCC patients who underwent radical surgery following neoadjuvant chemotherapy of cisplatin/5-FU were randomized to two arms, CHP-NY-ESO-1 vaccine and observation as a control arm. The vaccine was composed of 200 mg full-length NY-ESO-1 protein, which was subcutaneously given 15 doses with 2 or 4-week interval for 12 months. Primary endpoints were disease-free survival (DFS) and safety. Secondary endpoints were immune-responses and overall survival (OS). 49 patients were evaluated for DFS and OS. Results DFS in 2 years are 56.0% and 58.3% in the vaccine arm and in the control. OS in 2 years are 76.0% and 79.2%, respectively. No differences were seen between the vaccine and the control group. Subgroup analysis demonstrated that T-bet+ CD8+ T cell infiltration was significantly correlated to DFS and that PD-L1-expression in tumors showed unfavorable tendency for the vaccine group. Exploratory analysis of intra-cohort correlations among the vaccinated patients revealed that 5% or more expression of NY-ESO-1 and high polymeric immunoglobulin receptor (PIGR)-gene expression in tumors were favorable factors. Conclusions The clinical trial revealed that CHP-NY-ESO-1 vaccine alone did not display clinical efficacy compared to the control. It suggested that CHP-NY-ESO-1 vaccine would be indicated to > 5% NY-ESO-1 and/or high PIGR gene-expressing esophageal tumors that are infiltrated with activated T cells. Clinical trial identification UMIN000007905. Legal entity responsible for the study The authors. Funding Japan Agency for Medical Research and Development. Disclosure All authors have declared no conflicts of interest.

2530 Background: Adoptive transfer of TCR-redirected T cells has been reported to exhibit efficacy in some of melanoma and sarcoma patients. However, there have not been well known about cytokine release syndrome (CRS) or its relations to tumor responses. This study evaluates clinical responses in association with the cell kinetics and CRSs after transfer of high-affinity NY-ESO-1 TCR-gene transduced T cells in NY-ESO-1-expressiong cancer patients (NCT02366546). Methods: We developed a novel-type affinity-enhanced NY-ESO-1-specific TCR and an originally-developed retrovirus vector that encodes siRNA to silence endogenous TCR creation. The NY-ESO-1/TCR sequence is mutated for high affinity with replacements of G50A and A51E in CDR2 region. This is a first-in-man clinical trial of the novel NY-ESO-1-specfic TCR-T cell transfer to evaluate the safety, in vivo cell kinetics and clinical responses. It was designed as a cell-dose escalation from 5 x108 to 5 x109 cells. NY-ESO-1-expressing refractory cancer patients were enrolled, with 3+3 cohort design. Cyclophosphamide (1,500mg/m2) were administered prior to the TCR-T cell transfer as pre-conditioning. Results: 9 patients were treated with the NY-ESO-1/TCR-T cell transfer. The TCR-T cells expanded in peripheral blood with a dose-dependent manner, associated with rapid proliferation within 5 days after the cell transfer. 3 patients receiving 5x109 cells developed early-onset CRSs, with elevations of serum IL-6, IFN-γ. The CRSs developed on day1 or 2 after the cell transfer. They were well managed with tocilizumab treatment. 3 synovial sarcoma patients exhibited tumor shrinkages of partial responses, and they all had high-expression of NY-ESO-1 in the tumor samples, namely, 75% or more. Exploratory analysis revealed that multiple chemotactic cytokines including CCL2 and CCL7, and IL-3 increased in the serum from the patients with CRS. The proportions of effector-memory phenotype T cells in the infused cell-product were significantly associated with CRS development. Conclusions: The affinity-enhanced NY-ESO-1/TCR-T cell transfer exhibited early-onset CRS in association with in vivo cell proliferation and sequential tumor responses in the patients with high-NY-ESO-1-expressing synovial sarcoma. Clinical trial information: NCT02366546.

TPS11074 Background: Combination therapy to enhance the efficacy of T cell receptor (TCR)-engineered T cells (TCR-T) has received increasing attention. We found that a combination therapy of TCR-T and a long peptide vaccine with CpG adjuvant without lymphodepletion regimen caused regression of immune checkpoint inhibitor-resistant sarcoma in a preclinical mouse model. Based on this finding, we initiated a clinical trial of TBI-1301 combined with CHP:NE1 without lymphodepletion for the patients with NY-ESO-1-expressing advanced soft tissue sarcoma. TBI-1301 is an NY-ESO-1157–165/HLA-A*02:01- or -A*02:06-specific TCR-T engineered to reduce endogenous TCR mRNA expression. CHP:NE1 is a novel T cell stimulator consisting of NY-ESO-1 long peptide antigen, cholesteryl pullulan (CHP) nanogel, and CpG oligoDNA. CHP nanogel is used for efficient delivery of long peptide antigen into the lymph nodes. CpG oligoDNA is a TLR9 agonist and used as an adjuvant. CHP:NE1 is expected to reinforce TBI-1301 T cells in the lymph nodes. Methods: This is an investigator-initiated multi-institutional first-in-human phase I/II clinical trial. TBI-1301 is infused at 5×109 cells one day after subcutaneous injection of CHP:NE1. CHP:NE1 is injected again 7 days after TBI-1301 infusion. This cycle is repeated once more. Lymphodepletion using cyclophosphamide and/or fludarabine is not performed. Key inclusion criteria include: refractory soft tissue sarcoma with NY-ESO-1 antigen expression, HLA-A*02:01- or HLA-A*02:06- positive, ECOG Performance Status 0 or 1, and adequate organ function. The primary objective is to assess the safety and efficacy in the phase 1 and 2 parts, respectively. The secondary objective is to assess the efficacy and immune response (blood concentration, immunophenotype and activity of TBI-1301) in the phase 1 part and the safety and immune response in the phase 2 part. Enrollment in this study is currently ongoing. Clinical trial information: JMA-IIA00346.

Although adult T-cell leukemia (ATL) has a poor prognosis, successful allogeneic hematopoietic stem cell transplantation (allo-HSCT) in some cases suggests that a cellular immune-mediated strategy can be effective. So far, however, no effective target for anti-ATL immunotherapy has been defined. Here we demonstrated for the first time that human telomerase reverse transcriptase (hTERT) is a promising therapeutic target for ATL, and we developed a novel redirected T-cell-based immunotherapy targeting hTERT. hTERT messenger RNA was produced abundantly in ATL tumor cells but not in steady-state normal cells. Rearranged human leukocyte antigen-A*24:02 (HLA-A*24:02) -restricted and hTERT461-469 nonameric peptide-specific T-cell receptor (TCR) α/β genes were cloned from our previously established cytotoxic T lymphocyte clone (K3-1) and inserted into a novel retroviral TCR expression vector encoding small interfering RNAs for endogenous TCR genes in redirected T cells (hTERT-siTCR vector). Consequently, allogeneic or autologous gene-modified CD8(+) T cells prepared using the hTERT-siTCR vector successfully killed ATL tumor cells, but not normal cells including steady-state hematopoietic progenitors, in an HLA-A*24:02-restricted manner both in vitro and in vivo. Our experimental observations support the development of a novel hTERT-targeting redirected T-cell-based adoptive immunotherapy for ATL patients, especially those for whom suitable allo-HSCT donors are lacking.

Cancer vaccines have yet to yield clinical benefit, despite the measurable induction of humoral and cellular immune responses. As immunosuppression by CD4(+) CD25(+) regulatory T (Treg) cells has been linked to the failure of cancer immunotherapy, blocking suppression is therefore critical for successful clinical strategies. Here, we addressed whether a lyophilized preparation of Streptococcus pyogenes (OK-432), which stimulates Toll-like receptors, could overcome Treg-cell suppression of CD4(+) T-cell responses in vitro and in vivo. OK-432 significantly enhanced in vitro proliferation of CD4(+) effector T cells by blocking Treg-cell suppression and this blocking effect depended on IL-12 derived from antigen-presenting cells. Direct administration of OK-432 into tumor-associated exudate fluids resulted in a reduction of the frequency and suppressive function of CD4(+) CD25(+) Foxp3(+) Treg cells. Furthermore, when OK-432 was used as an adjuvant of vaccination with HER2 and NY-ESO-1 for esophageal cancer patients, NY-ESO-1-specific CD4(+) T-cell precursors were activated, and NY-ESO-1-specific CD4(+) T cells were detected within the effector/memory T-cell population. CD4(+) T-cell clones from these patients had high-affinity TCRs and recognized naturally processed NY-ESO-1 protein presented by dendritic cells. OK-432 therefore inhibits Treg-cell function and contributes to the activation of high-avidity tumor antigen-specific naive T-cell precursors.

Since 2009, a cancer vaccine clinical trial was conducted with melanoma antigen gene-A4 as an immunogenic agent. The levels of IgG1, IgG2 and IgG3, which are known to be Type 1 T helper cell-associated antibodies, and the levels of IgG4 and IgE, which are known to be Type 2 T helper cell-associated antibodies, were measured and used as biomarkers for predicting therapeutic effect. The results of the present study indicated a strong positive correlation between IgG2 and IgG4, with a correlation coefficient of R=0.808 (P

Carcinoembryonic antigen (CEA) is a cell surface antigen highly expressed in various cancer cell types and in healthy tissues. It has the potential to be a target for chimeric antigen receptor (CAR)-modified T-cell therapy; however, the safety of this approach in terms of on-target/off-tumor effects needs to be determined. To address this issue in a clinically relevant model, we used a mouse model in which the T cells expressing CEA-specific CAR were transferred into tumor-bearing CEA-transgenic (Tg) mice that physiologically expressed CEA as a self-antigen. The adoptive transfer in conjunction with lymphodepleting and myeloablative preconditioning mediated significant tumor regression but caused weight loss in CEA-Tg, but not in wild-type mice. The weight loss was not associated with overt inflammation in the CEA-expressing gastrointestinal tract but was associated with malnutrition, reflected in elevated systemic levels of cytokines linked to anorexia, which could be controlled by the administration of an anti-IL-6 receptor monoclonal antibody without compromising efficacy. The apparent relationship between lymphodepleting and myeloablative preconditioning, efficacy, and off-tumor toxicity of CAR-T cells would necessitate the development of CEA-specific CAR-T cells with improved signaling domains that require less stringent preconditioning for their efficacy. Taken together, these results suggest that CEA-specific CAR-based adoptive T-cell therapy may be effective for patients with CEA+ solid tumors. Distinguishing the fine line between therapeutic efficacy and off-tumor toxicity would involve further modifications of CAR-T cells and preconditioning regimens.

Forkhead box protein p3 (Foxp3) is crucial to the development and suppressor function of regulatory T cells (Tregs) that have a significant role in tumor-associated immune suppression. Development of small molecule inhibitors of Foxp3 function is therefore considered a promising strategy to enhance anti-tumor immunity. In this study, we developed a novel cell-based assay system in which the NF-κB luciferase reporter signal is suppressed by the co-expressed Foxp3 protein. Using this system, we screened our chemical library consisting of approximately 2,100 compounds and discovered that a cancer chemotherapeutic drug epirubicin restored the Foxp3-inhibited NF-κB activity in a concentration-dependent manner without influencing cell viability. Using immunoprecipitation assay in a Treg-like cell line Karpas-299, we found that epirubicin inhibited the interaction between Foxp3 and p65. In addition, epirubicin inhibited the suppressor function of murine Tregs and thereby improved effector T cell stimulation in vitro. Administration of low dose epirubicin into tumor-bearing mice modulated the function of immune cells at the tumor site and promoted their IFN-γ production without direct cytotoxicity. In summary, we identified the novel action of epirubicin as a Foxp3 inhibitor using a newly established luciferase-based cellular screen. Our work also demonstrated our screen system is useful in accelerating discovery of Foxp3 inhibitors.

Monoclonal antibody (mAb) therapy against tumor antigens expressed on the tumor surface is associated with clinical benefit. However, many tumor antigens are intracellular molecules that generally would not be considered suitable targets for mAb therapy. In this study, we provide evidence challenging this view through an investigation of the efficacy of mAb directed against NY-ESO-1, a widely expressed immunogen in human tumors that is expressed intracellularly rather than on the surface of cells. On their own, NY-ESO-1 mAb could neither augment antigen-specific CD8+ T-cell induction nor cause tumor eradication. To facilitate mAb access to intracellular target molecules, we combined anti-NY-ESO-1 mAb with anticancer drugs to accentuate the release of intracellular NY-ESO-1 from dying tumor cells. Strikingly, combination therapy induced a strong antitumor effect that was accompanied by the development of NY-ESO-1–specific effector/memory CD8+ T cells that were not elicited by single treatments alone. The combinatorial effect was also associated with upregulation of maturation markers on dendritic cells, consistent with the organization of an effective antitumor T-cell response. Administration of Fc-depleted F(ab) mAb or combination treatment in Fcγ receptor–deficient host mice abolished the therapeutic effect. Together, our findings show that intracellular tumor antigens can be captured by mAbs and engaged in an efficient induction of CD8+ T-cell responses, greatly expanding the possible use of mAb for passive cancer immunotherapy. Cancer Res; 72(7); 1672–82. ©2012 AACR.

Adoptive cell therapy using tumor-specific T cells is a promising strategy for treating patients with malignancy. However, accumulating evidences have demonstrated that optimal function of tumor-reactive T cells is often attenuated by negative regulatory signal(s) delivered through receptors, such as cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed death 1 (PD-1), and their cognate ligands. Although systemic blocking of these molecules needs careful attention on the risk of uncontrolled immune activation, selective inhibition of negative signals in tumor-specific T cells by their genetic modification is an attractive approach to overcome immunological suppression in cancer patients. Here, we demonstrate the improved effector functions of tumor-specific CD4(+) and CD8(+) human T cells by small interfering RNA (siRNA) -mediated silencing of PD-1 ligands, PD-L1 or PD-L2. Tumor antigen MAGE-A4-specific human T-cell clones upregulated the expression of PD-1 ligands upon activation. siRNA-mediated knockdown of PD-L1 or -L2 enhanced the interferon-γ production and antigen-specific cytotoxicity of these cells. Peripheral blood mononuclear cells transduced with a retroviral vector encoding MAGE-A4-specific T-cell receptor α/β chains also increased their effector functions by this modification. These results suggest that siRNA-mediated knockdown of PD-1 ligands is an attractive strategy to inhibit a negative regulatory mechanism of tumor-specific T cells resulting in enhanced efficacy of adoptive T-cell therapy of cancer using genetically modified autologous lymphocytes.