Search

Tumor-derived peptides can induce antitumor cytotoxic T lymphocyte(CTL)response. However, the effects are limited. We aimed to overcome this limitation by selectively delivering antigen peptides to an XC chemokine receptor 1-expressing dendritic cell subset(XCR1+DC)that is notable for its exceptional ability to generate CTL response. To do that, we designed a vaccine(mXCL1-OVA peptide vaccine)that consisted of a murine XCR1 ligand(XCL1)and an ovalbumin(OVA)-derived MHC class I-restricted antigen. When co-injected with the immune adjuvant polyinosinic-polycytidylic acid(poly[I: C]), mXCL1-OVA peptide vaccine showed much greater antigen-specific cytotoxic T cell(CTL)response than either OVA protein plus poly(I: C)or OVA peptide plus poly(I: C). Furthermore, mXCL1-OVA peptide vaccine plus poly(I: C)showed more prominent antitumor effects against OVA-expressing melanoma(B16-OVA)than other vaccines with regard to growth inhibition. Thus, our results suggest that chemokine-directed antigen delivery to DC subsets with high CTL-inducing ability is a promising method for generating effective antitumor immunity.

Recently, with the rapid development of elucidating the tumor immunological status, it has become clear that various lymphocytes, which are infiltrating tumor, are deeply involved in not only tumor growth but also its elimination. The interest and importance of cytotoxic T cells(CTLs)for cancer immunotherapy has been further increased, since CTLs play an important role in eliminating cancer cells by having high cytotoxic activity and high proliferation ability. To achieve potent antitumor effects, in addition to the anti-tumor immune response induced by various methods such as cancer peptide vaccine and immune checkpoint inhibitor, it is thought to be essential that CTLs should migrate and invade into localized cancer tissues. In this article, we will introduce the latest immunotherapies related to CTLs infiltration, and various methods to enhancement of CTLs infiltration into the cancer tissues.

Therapeutic cancer vaccine enhances a specific immune response against tumor cells in vivo, resulting in exertion of antitumor effects. On the other hand, immune checkpoint inhibitors promote the induction of tumor-specific T cells and also enhance the cytotoxic abilityof these T cells in tumor microenvironment. There is a possibilitythat immune checkpoint inhibitors enhance tumor immune responses induced bytherapeutic cancer vaccine, and it is expected that additive or synergistic effects will be obtained bythe combination of them. Moreover, according to previous reports, we should use an immune checkpoint inhibitor to enhance the cytotoxic ability of tumor-specific T cells as the combination for therapeutic cancer vaccine. Furthermore, the combination of a specific antibodyagainst newlyidentified co-inhibitoryreceptors (Lag-3, Tim-3, TIGIT, etc)and a therapeutic cancer vaccine is also one of newlyexpected treatments in the future.

Therapeutic cancer vaccines have been dramatically progressing in a variety of their forms for the last two decades. The CTIepitope peptide vaccines are one of them. We proposed the personalized peptide vaccine (PPV) therapy. Our PPV is different from the classical one in that a maximum of four peptides are selected based on the patient's HLA-A types and.their pre-existing immunity (=immunological memory), leading to the more rapid and stronger re- sponses to the vaccinated peptides. Since then, we have been conducting clinical studies for various types of advanced cancers. We summarized the clinical outcomes of the PPV studies and described its prospect for the clinical application.

Wilms'tumor gene 1(WT1) is a leukemia cell-specific marker, and WT1 protein is pan- tumor-associated antigen (TAA) that was ranked as a top among 75 TAAs. WT1 peptide vaccine has been performing for over 800 patients with 58 kinds of malignancies including leukemia and various types of solid tumors. Clinical results are promising, and adverse effects are limited to skin eruption on the vaccine injection sites. Two types of WT1 peptide vaccines are under clinical studies by pharmaceutical companies for the development of medicine.

ATL is a HTLV-1 induced T-cell malignancy with extremely poor prognosis. HTLV-1 Tax which is regulatory protein encoded in the pX region plays a crucial role in HTLV-1 leukemo- genesis and is a major target antigen for CTL. We conducted a clinical trial of Tax targeted therapeutic vaccine consisting of autologous dendritic cells (Tax-DC). The good quality of lives and long-term treatment-free survival were observed for more than 3 years in two of three patients enrolled in the pilot study. Tax-specific proliferative CTL responses were ob- served in all cases and the sporadic augmented responses also have been detected subse- quently. Tax-DC vaccine might be a well-tolerated and long-lasting maintenance therapy that is acceptable for even elderly patients.

Identification of tumor-associated antigens (TAAs) recognized by T cells has enabled clinical peptide vaccination trials targeting TAAs to be performed for patients with carcinoma or sarcoma. Although peptide vaccination could elicit specific immunological responses, clinical objective responses were not frequently observed, especially in end-stage patients with large tumor burdens who were receiving high-dose chemotherapy. The key points for developing effective peptide vaccination therapy are (i) targeting cancer stem-like cell antigens that are expressed in cancer cells but not in normal cells and regulating tumorigenesis and (ii) manip- ulating memory T stem cells that have the capacity of long-living and resistance to chemo- therapeutic drugs. The combination of a peptide vaccination and immune checkpoint inhibi- tors might also be attractive.

Recently, immunotherapy has been utilized as a novel option for the treatment of various malignancies, however, it is necessary to develop immune cell therapy on the basis of the blockade of immune checkpoints, antigen presentation on dendritic cell (DC) vaccines and the high avidity tumor reactive T cells. Autologous tumor lysate-loaded DC vaccines could have a potency to elicit T cells immune response with both epitopes of neoantigen and com- mon antigen; however the innate immunity should be essential for the cross-presentation process. Furthermore, DC vaccines loaded with tumor lysates by electroporation system eli- cited both antigen-specific CD8 and CD4 T cells. In order to break the immunosuppression, the combined therapy of the tumor lysate-loaded DC vaccines and immune checkpoint inhib- itors should be investigated in the future.

We assessed the efficacy of WT1 class I peptide and WT1 class II peptide pulsed dendritic cell(DC)therapy for a wide range of advanced cancers. This retrospective study included 60 advanced cancer patients who were vaccinated 5times or more in this clinic between September 2013 and December 2015. The clinical response was examined. This treatment was approved by the ethics panel at this institution. Sixty patients were injected an average of 6.15times with dendritic cells(DCs) (2.6×10 / 7 cells/injection). Overall, 55of 60(92%)patients achieved a clinical benefit per the RECIST v1.1 criteria. The median survival time(MST)from diagnosis was 26.9 months, and the MST from the first admission at this institution was 12.2 months. Complete response(CR)was achieved in 5patients(9.1%), partial response(PR)in 12(22%), and stable disease(SD) in 21(38%), with confirmed progressive disease(PD)in 17(31%). In 11 cases of pancreatic cancer, the response(RR)and disease control rates(DCR)were 27%and 55%,respectively. In 8 cases of colorectal cancer, the rates were 25% and 75%; in 7 cases of lung cancer, the rates were 29% and 43%; in 7 cases of gastric cancer, the rates were 71% and 86%; in 22 other types, the rates were 23% and 74%. These results demonstrated the potential clinical efficacy of DC-based immunotherapy.

Our previous phase II clinical trial showed that therapeutically selected personalized peptide vaccines(PPVs)were effective at boosting anticancer immunity; the immune response after PPV was associated with a clinical outcome as a prognostic factor for metastatic breast cancer(mBC). We conducted an early phase II study to evaluate the safety and efficacy of a new regimen using multiple peptide vaccines(KRM-19)for patients with metastatictriple -negative breast cancer. KRM-19 consisted of 19 mixed peptides chosen from the previously reported 31 PPVs according to their anti-tumor immunologiceffec ts and safety profiles for patients with mBC. All patients had histologically confirmed measurable ER-PgR-HER2- mBC and their human leukocyte antigen(HLA) / -A molecules were A2, A3, A11, A24, A26, A31, or A33. KRM-19(19mg/mL)was administrated subcutaneously every week for a total of 6 doses. Concurrent conventional chemo- and/or endocrine therapy were not permitted during treatment. This was an open-label, early phase II study. The primary endpoint was safety and anti-tumor immunologic effect, while the secondary endpoints were clinical responses and progression-free survival(PFS). The estimated enrollment was 10-15 and 8 patients were enrolled(Clinical trial registry number: UMIN000014616). Measurement of peptide-specific cytotoxic T lymphocyte and IgG responses were conducted before and after vaccination. The correlation between PFS and the increased IgG response and/or CTL levels were investigated.

The difficulty in obtaining a sufficient number of functional dendritic cells(DCs)is a well-known serious problem in DCbased immunotherapy. Therefore, we used induced pluripotent stem cell-derived DCs(iPSDCs). We have reported that mouse iPSDCs are equivalent to BMDCs, in terms of maturation and antigen presentation. In this study, the antitumor immune response of human iPSDCs expressing the carcinoembryonic antigen was examined, to determine its clinical application in gastrointestinal cancer. Human iPS cells were established from healthy human fibroblasts using a Sendai virus vector, and human iPSDCs were differentiated under a feeder-free culture. Additionally, the surface marker expression, cytokine production, and migratory capacity of human iPSDCs were equivalent to those of monocyte-derived DCs(MoDCs). After 3 cycles of stimulation of autologous PBMCs by genetically modified DCs, the 51Cr-release assay was performed. The lymphocytes stimulated by iPSDCs-CEA showed cytotoxic activity against LCL-CEA and CEA652-pulsed LCL, but showed no cytotoxicity against LCL-LacZ. In addition, they showed cytotoxic activity against CEA-positive human cancer cell lines, MKN45 and HT29, but showed no cytotoxicity against CEA-negative human cancer cell line MKN1. In conclusion, CEA-specific CTLs responses could be induced by iPSDCs-CEA. This vaccination strategy may be useful in future clinical applications of cancer vaccines.

During cancer progression, many somatic mutations accumulate in cancer cells. Antigens derived from tumor-specific mutated genes are primary sources ofneoantigens in cancer immunology. As compared with non-mutated self-antigens, neoantigens are thought to have higher antigenicity, and are expected to be ideal targets for tumor rejection. Recent studies demonstrate that T cells recognize neoantigens and elicit immune responses against tumor cells. The importance ofneoantigens in cancer immunity has been well acknowledged, and development ofneoantigen -targeted cancer immunotherapy is in progress worldwide. High-throughput detection ofsomatic mutations by whole-exome sequencing is combined with computational algorithm for MHC-peptide binding affinity to predict potential neoantigens. After the antigenicity is confirmed by immunological assays, personalized vaccines targeting the identified neoantigens will be generated with peptides, dendritic cells, or RNAs. Such neoantigen-targeted cancer vaccines are being developed for practical use. In fact, several clinical trials have already been initiated in Europe and the US.

Since the discovery of the human T cell-defined tumor antigen, the cancer immunotherapy field has rapidly progressed, with the research and development of cancer immunotherapy, including cancer vaccines, being conducted actively. However, the disadvantages of most cancer vaccines include relatively weak immunogenicity and immune escape or exhaustion. Adjuvants with innate immunostimulatory activities have been used to overcome these issues, and these agents have been shown to enhance the immunogenicity of cancer vaccines and to act as mono-therapeutic anti-tumor agents. CpG ODN, an agonist for TLR9, is one of the promising nucleic acid-based adjuvants, and it is a potent inducer of innate immune effector functions. CpG ODN suppresses tumor growth in the absence of tumor antigens and peptide administration. Therefore, CpG ODN is expected to be useful as a cancer vaccine adjuvant as well as a cancer immunotherapy agent. In this review, we discuss the potential therapeutic applications and mechanisms of CpG ODN for cancer immunotherapy.

Targeted therapies and immunotherapies attack tumor cells through different mechanisms. In addition, these therapies exhibit quick and delayed effects, respectively, and therefore, these therapies are complementary. Furthermore, targeted therapies may enhance the function of immune cells, and therefore, both the therapies are expected to have a synergistic effect. Antitumor immune responses comprise several steps including dendritic cell activation, T cell activation, and dampening tumor-induced immunosuppression; targeted drugs that work at each step have been reported. Clinical trials of rational combinations of both therapies, while avoiding severe adverse events, will greatly advance cancer treatments in the near future.

Patient satisfaction with cancer immunotherapy, which is not covered by health insurance in Japan, was evaluated among 65 patients with advanced cancer who had received immunotherapy in our hospital for 2 years. Satisfaction measures were based on patients' expectations for medical care, cost, and staff services, and involved a questionnaire consisting of 25 items. Results of the questionnaire analysis showed that most patients, who expected much of antigen-specific vaccination such as dendritic cells (DC) pulsed tumor-associated antigens, were dissatisfied with the high cost of private immunotherapy(i. e., not covered by medical insurance), and were unable to perceive the effectiveness of the treatment because there was no quantitative analysis of killer T cells induced by immunotherapy. Therefore, it is critically important for us to confirm the safety and efficiency of cancer immunotherapy, before introducing medical insurance for cancer patients in Japan. In addition, the quantitative measurement of killer T cells induced by DC peptide vaccines should be considered, to meet patients' expectations.

We conducted a clinical trial of a seven-peptide vaccine in combination with tegafur-uracil/Leucovorin for advanced colorectal cancer. These antigenic peptides were derived from 5 proteins identified as cancer-testis antigens(ring finger protein 43 [RNF43], translocase of outer mitochondrial membrane 34[TOMM34], maternal embryonic leucine zipper kinase[MELK], forkhead box M1[FOXM1], and holliday junction recognition protein[HJURP])and 2 vascular endothelial growth factor receptors(VEGFR1 and VEGFR2). Thirty patients with advanced colorectal cancer were enrolled. We found that 25 patients had Grade 1 injection-site redness/induration and 1 patient had Grade 3 anaphylaxis. Tumor imaging revealed that 3 patients had a partial response (PR), 15 had stable disease(SD)and 12 had progressive disease(PD). This trial showed that treatment with the seven-peptide vaccine and UFT/LV was well tolerated and feasible for advanced colorectal cancer.

A 66-year-old woman was diagnosed with pancreatic tail cancer, and she was referred to our hospital. Abdominal computed tomography(CT)revealed a tumor(2.5 cm in diameter)in the pancreatic tail, with invasion to the spleen and splenic vein. In February 2013, we performed distal pancreatectomy with splenectomy, left adrenal gland resection, and D2 lymph node dissection. Diagnostic peritoneal lavage cytology during surgery was positive; however, we performed curative resection because there were no signs of peritoneal dissemination and distant metastasis. The patient was discharged from the hospital 23 days after the operation, with good postoperative course. Histological diagnosis was pancreatic tail cancer, pT4N0H0P0M(-) fStage IVa. Subsequently, the patient received postoperative adjuvant chemotherapy(TS-1: 100mg/day, 4 courses)combined with Wilms'tumor 1(WT1)peptide-pulsed dendritic cell therapy. No serious adverse events occurred during the postoperative adjuvant therapy. The patient remains alive without recurrence 16 months after the operation.

We assessed the efficacy of Wilms' tumor protein-1(WT1)peptide and/or mucin 1(MUC-1)peptide-pulsed dendritic cell(DC)therapy for a wide range of advanced cancers.This retrospective study included 313 patients with advanced cancer who were vaccinated ≥5 times in our clinic between May 2009 and October 2013.T he clinical response was evaluated.This treatment was approved by the ethics panel of our institution.A total of 313 patients were injected an average of 6.0 times with DCs(2.4×10 / 7 cells/injection).Overall, 292 of the 313(93%)patients obtained clinical benefit according to the Response Evaluation Criteria in Solid Tumors(RECIST), version 1.1. The median survival time(MST)from diagnosis and from first being admitted to this institution was 28.4 months and 13.2 months, respectively. Complete response(CR)was achieved in 21 patients(7.2%).Partial response(PR)was achieved in 69 patients(24%).Stable disease(SD)was observed in 107 patients(37%), and progressive disease(PD)was observed in 95 patients(33%).The response rate(RR)and disease control rate(DCR)for each type of cancer were as follows: colorectal cancer(56 patients), 25%and 45%, respectively; lung cancer(39 patients), 31% and 82%, respectively; pancreatic cancer(36 patients), 22% and 64%, respectively; gastric cancer( 34 patients), 32% and 74%; breast cancer(20 patients), 15% and 75%, respectively; ovarian cancer(16 patients), 19% and 50%, respectively; esophageal cancer(15 patients), 20% and 73%, respectively; and others(76 patients), 38% and 67%.These results demonstrated the potential clinical effectiveness of DC-based immunotherapy.

It is generally accepted that the difficulty in obtaining a sufficient number of functional dendritic cells (DCs) poses a serious problem in DC-based immunotherapy. Therefore, we used induced pluripotent stem (iPS) cell-derived DCs (iPSDCs) instead. If the therapeutic efficacy of iPSDCs was equivalent to that of bone marrow-derived DCs( BMDCs), then the above-mentioned problems may be solved. In this study, we generated iPSDCs from iPS cells and compared their capacity to mature and migrate to the regional lymph nodes with that of BMDCs. We adenovirally transduced the hgp100 gene, which codes for a natural tumor antigen, into the DCs and immunized the mice with these genetically modified DCs. The cytotoxic activity of CD8( +) cytotoxic T lymphocytes( CTLs) was assayed using a 51Cr-release assay. The therapeutic efficacy of the vaccination was examined in a subcutaneous tumor model. Our results demonstrated that iPSDCs equaled BMDCs in terms of their maturation and migration capacity. Furthermore, hgp100-specific CTLs were generated in mice that were immunized with the genetically modified iPSDCs. These CTLs exhibited a high level of cytotoxicity against B16 cells, which is similar to that exhibited by CTLs generated in BMDCs immunized mice. Moreover, vaccination with genetically modified iPSDCs elicited a high level of therapeutic efficacy equaling that of vaccination with BMDCs. This study clarified experimentally that genetically modified iPSDCs are equivalent to BMDCs in terms of tumor-associated antigen-specific therapeutic antitumor immunity. This vaccination strategy may therefore be useful for future clinical application as a cancer vaccine.

Complementary DNA( cDNA) microarray technology coupled with laser microdissection has been used to identify human leukocyte antigen (HLA)-A24-restricted epitope peptides as potential targets for cancer vaccination in colorectal cancer patients. These antigenic peptides were derived from 2 different cancer-testis antigens, ring finger protein 43 (RNF43) and translocase of outer mitochondrial membrane 34( TOMM34). We conducted a clinical trial of colorectal cancer-specific peptide( RNF43, TOMM34) vaccines with uracil/tegafur( UFT)+Leucovorin( LV) for the treatment of advanced or recurrent colorectal cancer. The vaccinations were well tolerated without any serious adverse events. There were long-term survivors in the group showing cytotoxic T lymphocyte (CTL) responses against both RNF43 and TOMM34, as well as in the group showing CTL responses against either RNF43 or TOMM34. A new study has been planned to obtain more immunological responses. We started a clinical trial of vaccines against multiple peptides (RNF43, TOMM34, forkhead box protein M1 [FOXM1], maternal embryonic leucine zipper kinase [MELK], holliday junction recognition protein[HJURP], vascular endothelial growth factor receptor 1[VEGFR1], and VEGFR2) for the treatment of advanced or recurrent colorectal cancer.

Molecular identification of tumor antigens has made possible to develop tumor-specific immunotherapy. Provenge was approved by FDA as a first therapeutic drug for cancer in 2010. A line of drug candidates is in late phase clinical trials as therapeutic vaccine for patients with solid tumors. Adoptive immunotherapy with tumor-specific T cells demonstrated clinical effectiveness in patients with advanced malignancy such as metastatic melanoma and synovial cell sarcoma. Genetically engineered T cells were administrated to cancer patients with promising results and may extend the application of adoptive immunotherapy of tumor. Although recent findings in tumor biology and immunity suggest the integrated immune response against tumor with special emphasis on inhibitory mechanism, we are unmistakably witnessing the moment that immunotherapy of cancer becomes a medical option.

Wilms' tumor gene WT1 encodes a transcription factor and functions as an oncogene. WT1 gene product WT1 protein is a promising par-tumor-associated antigen. WT1 peptide-based immunotherapy has been performing for more than six hundred patients with leukemias and various types of solid tumors. This immunotherapy is safe and has clinical benefit especially for leukemia, glioblastoma multiforme, advanced pancreatic cancer, and ovarian cancer. As a new strategy for cancer treatment, it should be recommended to initiate immunotherapy that had a potential of eradication of cancer stem cells before surgery, chemo- and radio-therapy.

We conducted personalized peptide vaccination (PPV) for various types of advanced cancers in the past 10 years. A maximum of four HLA-matched peptides, which were selected based on the pre-existing host immunity before vaccination, were subcutaneously administered at PPV trials. Randomized phase II trial for patients with castration resistant prostate cancer showed the favorite clinical responses in the PPV group. PPV was also conducted for recurrent or progressive glioblastoma multiforme patients with median overall survival of 10.6 months, resulting in the initiation of randomized phase III clinical trial. A randomized phase III trial is essential to prove clinical benefits of PPV.

For the breakthrough of the tumor escape mechanisms, immuno-chemo-combined therapy has been conducted. Tumor cell killing by anticancer drugs may be supported by their immuno- and pharmacologic effects. Chemotherapy is in fact able to up regulate tumor-associated antigen expression, and down regulate tumor cell resistance to the cytotoxic T lymphocytes. We conducted a phase II trials, administration of epitope peptides with FOLFOX to evaluate immunologic and clinical responses. Research into biomarkers that correlate with the clinical outcome of immunotherapy has behind vaccine development. Very few immunological or other markers exist that can be used in clinical trials for immunotherapy. We discuss with biomarkers specifically for the efficacy and monitoring of cancer vaccines.

Despite advances in treatment modalities, malignant solid tumors remain devastating maladies. Conventional treatment with chemotherapy and radiation is still only partially effective and highly toxic. In the era of increasing knowledge of the molecular biology of tumors and the interaction between the tumor and immune system, the development of targeted agents, including cancer vaccines, has emerged as a promising modality. This article will summarize the recent progress in developing cancer vaccines and immunotherapeutic approaches including adoptive cell transfer and will further review currently ongoing phase II/III studies for malignant solid tumors in the world.

Cancer therapy utilizing cellular immunity has been developed using various reagents including stimulus for innate immunity, cytokines, vaccines, autologous cells and gene-vectors. Recently, mono-clonal antibodies have been added to the list as well. These reagents of modalities have been developed base on the findings in the basic research in cellular immunology which has been proven to have potent activities to suppress the tumor growth in either in vitro or in vivo. This review describes the characteristics of the reagents of modalities focusing on their mechanisms of action.

NY-ESO-1 antigen is a prototype of a class of cancer/testis antigens. We carried out three serial clinical trials using NY-ESO-1 whole protein, NY-ESO-1f long peptide and overlapping peptides as a cancer vaccine for advanced cancer patients. Although vaccines elicited NY-ESO-1 humoral and cellular immune responses in most patients, results of immune monitoring using peripheral blood was not consistent with clinical responses. Analysis of immunohistochemistry revealed possible involvement of regulatory mechanisms in local antitumor immunity. Immune checkpoint molecules, e.g., CTLA-4 and PD-1, on immune effector cells, and regulatory T cells are known to regulate the induced immune responses and minimize local tissue damage. We should take these factors into consideration for further strategy of cancer vaccine and its monitoring.

The carcinoembryonic antigen glypican-3 (GPC3) is an ideal target of tumor antigen-specific immunotherapy against hepatocellular carcinoma (HCC), because it is overexpressed specifically in HCC. We have reported that a GPC3-derived peptide vaccination was well-tolerated, and immune responses and antitumor efficacy were noted in a phase I trial for HCC patients. We have begun a phase II study of the GPC3-derived peptide vaccine as an adjuvant therapy for HCC patients, and a pilot study of liver biopsies performed before and after GPC3 peptide vaccination for advanced HCC to determine whether tumor-infiltrating lymphocytes are indeed GPC3 peptide-specific CTLs. Furthermore, we are initiating clinical trials of a GPC3-derived peptide vaccine for patients with hepatoblastoma or ovarian clear cell carcinoma.

Cancer immunotherapy has shown much potential, but is not yet beneficial for all patients. Acquired immunity after immunotherapy can be assessed by a variety of methods; however, the methods for the prediction of such responses before treatment are quite limited. To challenge this classic problem, we quantified 17 different leukocyte function-associated mRNAs( IFN-γ,TNFSF1, TNFSF2, TNFSF5, IL-10, TGF β,CTLA4, PD1, FOXP3, GMCSF, VEGF, IL-8, CCL8, CXCL3, and IL-2) in whole blood after ex vivo stimulation with 7 different agents(PHA, HAG, zymosan, IFN-γ,rIL-2, aTCR, and picibanil) to activate various subsets of leukocytes. The mRNAs were quantified by the Hitachi Chemical Research Center, Inc. Irvine, CA. The clinical outcomes for WT1 peptide-and/or MUC1 peptide-pulsed dendritic cell therapy for advanced cancer (n=26) were CR+PR, 4 cases; SD, 9 cases; and PD, 13 cases. The accuracy of prediction was found to be 100% using the formula developed by multivariate discriminant analysis of the values for ex vivo induced mRNAs. Because the volume of blood needed for this test is less than 1.5 mL, and because cell isolation and culture are not necessary, this method will become a model of personalized medicine diagnostics for cancer immunotherapy.

During past decades, cancer vaccine therapy has been focused on only the activation of CTL, but its therapeutic effect was not successful though long SD was induced. The failure of cancer vaccine is derived from (i) the existence of a strong tumor escape mechanisms and (ii) the ignorance of helper T cell activation. We have proposed that Th1-dominant immunity played a critical role for overcoming immunosuppressive tumor-escape mechanisms to induce tumor-specific CTL, which are essential for the complete cure of tumor and prevention of tumor recurrence. To apply these basic findings, we started a clinical trial of a novel cancer vaccine/cell therapy (Th1 cell therapy) using H/K-HELP of MAGE-A4 or Survivin cancer antigen. In phase I study, H/K-HELP consisted of both killer and helper epitopes and Th1 adjuvants (OK-432 and Montanide) were subcutaneously administered into cancer patients 4 times at 2 wks intervals. Both MAGE-A4-H/K-HELP and Survivin-H/K-HELP cancer vaccine induced cancer-specific Th1 and Tc1 immune responses and cancer-specific C-fixing antibodies (IgG1 and IgG3) in cancer patients. Moreover, Survivin-H/K-HELP vaccination induced a complete regression of chemo and radio-resistant lateral deep cervical node recurrence of triple-negative breast cancer. H/K-HELP vaccination with Th1 adjuvants or its combination with Th1 cells will become a promising cancer vaccine/cell therapy of human cancer.

Patients with advanced carcinoma are thought to have an impaired immune surveillance system. Therefore, the potent helper action is required for the induction of an antitumor immune response in such patients. We evaluated the efficacy of CpG-ODN, which is TLR-9 agonist, as cancer vaccine adjuvant through in vitro experiments. We also conducted a phase I clinical trial for patients with advanced esophageal squamous cell carcinoma (ESCC) using peptide vaccine in combination with CpG-B. In vitro experiments showed that CpG-ODN caused various immune-modifications, suggesting an efficacy of CpG-ODN as peptide vaccine adjuvant. Moreover, the immune monitoring data in phase I clinical trial suggested that CpG-B augmented the generation of antigen-specific T cell responses and innate immunity. These data indicated that the vaccination with cancer-testis antigen derived peptide in combination with CpG-B may be useful as a new immunotherapy for patients with advanced ESCC.

cDNA microarray technology has been used to identify HLA-A24-restricted epitope peptides as potential targets for cancer vaccination in metastatic colorectal cancer patients. We conducted a clinical trial of two novel cancer-specific peptides( RNF43, TOMM34) with UFT/LV for the treatment of recurrent colorectal cancer. Among 23 patients, 21 patients had completed the protocol. All patients were well tolerated with no severe toxicities. The median survival time was 24.4 months. Furthermore, we investigated the relationship between CTL response to both antigens and overall survival. The best long-term survival was observed in the group with CTL responses against both antigens, followed by the group showing CTL responses against only RNF43 or TOMM34. The patients with no response had the lowest survival. Based on the results, we started a randomized trial of the current protocol, as adjuvant immunochemotherapy in following curative resection of Stage III colorectal cancer patients.

Vascular endothelial growth factor receptor 2 (VEGFR2) is an essential factor in tumor angiogenesis and the growth of pancreatic cancer. In addition, it is overexpressed in tumor blood vessels, however, VEGFR2 is not expressed in normal vessels, which makes an attractive candidate as a molecular target for antiangiogenic cancer immunotherapy. Furthermore, the tumor cell-indirect immunotherapy targeting VEGFR2 is expected to overcome tumor immune escape. The phase I clinical trial using VEGFR2-169 peptide that successfully induced specific CTLs in cancer patients, combined with gemcitabine (GEM), was conducted for patients with advanced pancreatic cancer. VEGFR2-169 was subcutaneously injected weekly in a dose-escalation manner( doses of 0.5, 1.0, 2.0 mg/body, 6 patients/1 cohort). GEM was administered at a dose of 1,000 mg/m2 on days 1, 8 and 15 in a 28-day cycle. No dose limiting toxicity was observed. Specific CTLs reacting to VEGFR2-169 were induced in 11 (61%) of the 18 patients. Our protocol was safe and well-tolerated. VEGFR2-169 was immunogenic under the condition with GEM treatment. From an immunological point of view, the optimal dose might be 2.0 mg/body. A randomized phase II/III clinical trial started in January 2009 to demonstrate the clinical benefits of VEGFR2-169 for advanced pancreatic cancer patients.

The field of cancer vaccines has moved forward dramatically, along with the progressive increase in basic knowledge of tumor immunology. During the last 20 years, a number of tumor-associated antigens have been identified, some of which have been clinically examined in patients, demonstrating encouraging results as immunotherapy against various types of cancers. However, most of the randomized clinical trials conducted to gain approval for official clinical use of the antigens have failed, due to an inability to demonstrate thair meaningful therapeutic benefit to patients over other existing treatments, with the exception of the dendritic cell(DC)-based vaccine(Provenge®), which has recently been approved as the first therapeutic cancer vaccine in the US. Such unexpected results have shed light on several important issues to solve in regard to further development of cancer vaccines. In particular, more attention should be paid to the fact that the characteristics of tumor cells and the immunological status against cancers differ widely among patients. Of note, the recent failure of cancer vaccines in clinical trials may be explained, at least in part, by the existence of a vaccine-specific adverse event; an induction of an"inconvenient immune response,"that inhibits pre-existing host immunity. Development of a novel criteria and reliable biomarkers for selecting adequate patients and vaccine antigens would be a breakthrough for further cancer vaccine development. In this review, we will summarize the current status of cancer vaccine development and discuss how to overcome negative issues raised in recently conducted clinical trials of therapeutic cancer vaccines.

For cervical cancer prevention, Cervarix(HPV-16/18)was approvedin Japan andvaccination programs against HPV-16/18 were startedin December, 2009. This vaccine is almost 100% effective in preventing high-grade precancer associated with the HPV types; it is safe and well tolerated. In Japan, universal vaccination of females between 11 and 14 years is recommended. We all look forward to eradicating cervical cancer in the not too distant future.

A 53-year-old woman presented with a diagnosis of advanced gallbladder cancer at our hospital. She was evaluated with CT scan and given a diagnosis of Stage IVb due to the multiple lymph nodes metastases and significant invasion to the artery. However, we underwent simple cholecystectomy followed by immunotherapy that was the hope of herself and her family. The serum level of DUPAN-2 was gradually elevated to 6,800 U/mL, and the metastases to the liver were detected. After we started the dendritic cell vaccine pulsed with autologous tumor-lysate with S-1, DUPAN-2 decreased to 980 U/ mL. The CT scan showed complete response (CR) in the liver metastases and partial response (PR) in the lymph node metastases. However, the serum level of CEA elevated since the MUC-1 peptide was used instead of autologous tumor- lysate, even DUPAN-2 did not. The liver metastases were in control, but the lymph nodes metastases had progressed. She died of the progressed lesion later in approximately one year from the operation. This case demonstrated a possibility of the tumor escape mechanism by changing their tumor-associated antigens.

The clinical outcome of intra-hepatic cholangiocelluler carcinoma (ICC) is very poor. To prevent a tumor relapse after curative operation, we employed the combination therapy of adaptive transfer of anti-CD3 activated T cells and dendritic cell vaccine therapy (DC-CAT therapy) since 2000. During DC-CAT therapy, about a half of patient revealed skin reaction positive. Moreover, the patient who had a skin reaction showed a significantly good clinical outcome. In this study, we investigated the difference between skin reaction positive and negative checking with the surface markers of T cells. The patient who had skin reaction positive increased the number of lymphocyte. Especially, CD8 positive T cells were increased about 2 folds in number before the DC-CAT therapy, and decreased Foxp3 positive regulatory T cells. Our data suggest that increasing cytotoxic T cells and decreasing regulatory T cells made the difference of the clinical outcome such as a disease free survival rate and overall survival rate after curative operation for ICC patient.