Pulsed Dendritic Cell Vaccine Research Articles

Immunological analysis of hybrid neoantigen peptide encompassing class I/II neoepitope-pulsed dendritic cell vaccine.

Neoantigens/ are tumor-specific antigens that evade central immune tolerance mechanisms in the thymus. Long-term tumor-specific cytotoxic T lymphocyte activity maintenance requires class II antigen-reactive CD4+ T cells. We had previously shown that intranodal vaccination with class I neoantigen peptide-pulsed dendritic cells (DCs) induced a robust immune response in a subset of patients with metastatic cancer. The present study aimed to perform a detailed ex vivo analysis of immune responses in four patients receiving an intranodal hybrid human leukocyte antigen class II neoantigen peptide encompassing a class I neoantigen epitope (hybrid neoantigen)-pulsed DC vaccine. After vaccination, strong T-cell reactions against the hybrid class II peptide and the class I-binding neoantigen peptide were observed in all four patients. We found that hybrid class II neoantigen peptide-pulsed DCs stimulated CD4+ T cells via direct antigen presentation and CD8+ T cells via cross-presentation. Further, we demonstrated that hybrid class II peptides encompassing multiple class I neoantigen epitope-pulsed DCs could present multiple class I peptides to CD8+ T cells via cross-presentation. Our findings provide insight into the mechanisms underlying hybrid neoantigen-pulsed DC vaccine therapy and suggest future neoantigen vaccine design.

Identification of Immunogenic MHC Class II Human HER3 Peptides that Mediate Anti-HER3 CD4+ Th1 Responses and Potential Use as a Cancer Vaccine.

The HER3/ERBB3 receptor is an oncogenic receptor tyrosine kinase that forms heterodimers with EGFR family members and is overexpressed in numerous cancers. HER3 overexpression associates with reduced survival and acquired resistance to targeted therapies, making it a potential therapeutic target in multiple cancer types. Here, we report on immunogenic, promiscuous MHC class II-binding HER3 peptides, which can generate HER3-specific CD4+ Th1 antitumor immune responses. Using an overlapping peptide screening methodology, we identified nine MHC class II-binding HER3 epitopes that elicited specific Th1 immune response in both healthy donors and breast cancer patients. Most of these peptides were not identified by current binding algorithms. Homology assessment of amino acid sequence BLAST showed >90% sequence similarity between human and murine HER3/ERBB3 peptide sequences. HER3 peptide-pulsed dendritic cell vaccination resulted in anti-HER3 CD4+ Th1 responses that prevented tumor development, significantly delayed tumor growth in prevention models, and caused regression in multiple therapeutic models of HER3-expressing murine tumors, including mammary carcinoma and melanoma. Tumors were robustly infiltrated with CD4+ T cells, suggesting their key role in tumor rejection. Our data demonstrate that class II HER3 promiscuous peptides are effective at inducing HER3-specific CD4+ Th1 responses and suggest their applicability in immunotherapies for human HER3-overexpressing tumors.

CTIM-18. DENDRITIC CELL VACCINATION IN CONJUNCTION WITH ADJUVANT TLR-3 AGONIST ADMINISTRATION ENHANCES PRO-INFLAMMATORY IMMUNE RESPONSES AND IS ASSOCIATED WITH EXTENDED SURVIVAL IN MALIGNANT GLIOMA PATIENTS

Abstract Despite recent advances with immunotherapy in other tumor types, malignant glioma patients have not shown a therapeutic benefit, potentially due to the insufficient activation of an immune response. We and others have documented immune responses and extended survival following dendritic cell (DC) vaccination in small clinical trials. In this Phase II clinical trial, we randomized malignant glioma patients to receive autologous tumor lysate pulsed DC vaccination with and without adjuvant toll-like receptor (TLR) agonists. Treatment with TLRs in cancer patients has been shown to activate the innate immune response by inducing the expression of pro-inflammatory factors and cytokines. Twenty-three patients with WHO grade III or IV glioma received three intradermal injections of autologous tumor lysate-pulsed DC on days 0, 14, and 28 in conjunction with either a placebo adjuvant, TLR-7 agonist (Resiquimod), or TLR-3 agonist (Poly ICLC). We observed a difference in survival for the DC-vaccinated patients who received adjuvant Poly ICLC treatment of 54 months over adjuvant placebo (20 months) and adjuvant Resiquimod (28 months) groups (P = 0.04). The patient cohorts were balanced for WHO grade, IDH mutation, and MGMT methylation status. Mass cytometry (CyTOF) analysis of patient peripheral blood mononuclear cells (PBMCs) showed increased levels of the monocyte populations CD14+CD16- and CD14dimCD16+ after Poly ICLC treatment. In addition, gene expression analysis of the PBMC populations using single cell RNA sequencing demonstrated increased expression of pro-inflammatory genes after adjuvant Poly ICLC and Resiquimod treatment. Nonetheless, a greater fold change increase and a larger pro-inflammatory repertoire was observed in the Poly ICLC group. Overall, these findings demonstrate that adjuvant Poly ICLC increases the number of circulating monocytes and induces a large pro-inflammatory response, which may account for the survival differences observed over adjuvant Resiquimod and placebo.

Vaccination with dendritic cells pulsed ex vivo with gp100 peptide-decorated liposomes enhances the efficacy of anti PD-1 therapy in a mouse model of melanoma

BackgroundTargeting antigens to dendritic cells (DCs) via nanoparticles is a powerful strategy which improves the efficacy of ex vivo antigen-pulsed DC vaccines. MethodsIn this study, liposomes were first decorated with gp10025-33 self-antigen and then characterized. Then, DCs were pulsed ex vivo with liposomal gp100 and injected subcutaneously in mice bearing B16F10 established melanoma tumors in combination with anti-PD-1 therapy. ResultsTreatment with liposomal pulsed DC vaccine elicited the strongest anticancer immunity and enhanced intratumoral immune responses based on infiltration of gp100-specific CD4+ and CD8+ T cells to the tumor leading to significant tumor growth regression and prolonged survival rate. Treatment with liposomal pulsed DC vaccine also markedly enhanced specific cytotoxic T lymphocytes (CTL) responses with a significant higher titer of IFN-γ in the spleen. Moreover, a significant increase of PD-1 expressing CD8+ tumor infiltrating lymphocytes (TILs) was detected in tumors. ConclusionOur results demonstrate an optimum dose of liposomal gp100 significantly increases the efficacy of anti-PD-1 therapy in mice and might be an effective strategy to overcome resistance to anti-PD-1 therapy.

Abstract PR13: Adjuvant TLR-3 administration enhances proinflammatory immune responses and is associated with extended survival in glioblastoma patients treated with dendritic cell vaccination

Abstract Malignant glioma, associated with a poor prognosis, is the most common primary malignant brain tumor in adults. We and others have documented immune responses following dendritic cell (DC) vaccination as an active immunotherapeutic treatment for these patients. In this phase II clinical trial, we randomized malignant glioma patients to receive autologous tumor lysate pulsed DC vaccination with and without adjuvant Toll-like receptor (TLR) agonists. TLRs are present on dendritic cells and serve to modulate immune responses. Twenty-three patients with WHO grade III or IV glioma were treated with three intradermal injections of autologous tumor lysate-pulsed DC on days 0, 14, and 28 followed by an adjuvant placebo, TLR-7 agonist (resiquimod), or TLR-3 agonist (Poly ICLC). Mass cytometry (CyTOF) was used to analyze immune cell populations of patient peripheral blood mononuclear cells (PBMC) before and following treatment. DC-vaccinated patients who received adjuvant Poly ICLC treatment had a significantly improved median survival of 54 months over placebo (11 months) and adjuvant resiquimod (17 months) groups (P<0.01). CyTOF and single-cell RNA sequencing (scRNseq) gene expression analysis of systemic PBMCs from patients demonstrated increased immune cell activation and expression of proinflammatory genes. Notably, the expansion of a heterogenous myeloid cell population was noted to correlate with increased survival, corroborating preclinical evidence that these cells modulate adaptive immunity in the tumor microenvironment. Overall, these findings suggest that adjuvant Poly ICLC treatment improves outcomes with autologous lysate-pulsed DC vaccine treatment via modulation of proinflammatory pathways. This abstract is also being presented as Poster B27. Citation Format: Joseph P. Antonios, Richard G. Everson, Aaron Mochizuki, Sara Khattab, Horacio Soto, Prashant Romiyo, Matthew Z. Sun, Diana Moughon, Emma Billingslea-Yoon, Sylvia Odesa, Gang Li, Eric Kawaguchi, Alex Salazar, William Yong, Jason Schlossman, Benjamin Ellingson, Anthony C. Wang, Timothy Cloughesy, Robert M. Prins, Linda M. Liau. Adjuvant TLR-3 administration enhances proinflammatory immune responses and is associated with extended survival in glioblastoma patients treated with dendritic cell vaccination [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr PR13.

Abstract 1451: HER2 peptide pulsed dendritic cell vaccine induce senescence and eliminates disseminated cancer cells in a preventive model of transgenic HER2/neu breast cancer

Abstract HER-2/neu overexpression plays a critical role in breast cancer development, and its expression in ductal carcinoma in situ (DCIS) is associated with development of invasive breast cancer. The detection of disseminated cancer cells (DCCs) in early-stage DCIS likely to become invasive and manifests prominent role in metastasis and recurrence. The HER2-positive DCCs can easily escape targeted therapies and become a source of tumor recurrence suggesting that targeting these cells may provide eminent benefits in HER2 positive breast cancer patients. Unfortunately, the conventional therapies that target these DCCs are limited. Previous studies from our lab have shown that HER2 peptide pulsed-DC1 (HER2-DC1) vaccine induced 30% complete response (pCR) in DCIS patients. However, little is known about the effect of HER2-DC1 vaccine on DCCs. Here, we investigated the efficacy of HER2-DC1 vaccine on DCCs in a transgenic HER2 mammary cancer model (neuT). The key features of this model are each one of ten mammary glands develops an independent carcinoma that slowly progresses from a microscopic lesion to an invasive tumor and metastasis is mainly driven by DCCs. Since this model mimics some of the most critical features of human disease, we evaluated the efficacy of HER2-DC1 vaccine on DCCs. Mice received six doses of HER2-DC1 vaccine subcutaneously twice a week. The spontaneous tumor development in the mammary glands of NeuT mice was examined once a week by ultrasound until the age of week 16. HER2-DC1 vaccine significantly prevented spontaneous tumor growth in NeuT mice. Remarkably, HER2-DC1 vaccine treatment significantly decreased HER2+CYT8/18+Ki-67+ proliferative DCCs (2%, p<0.002) in the bone marrow (BM-DCCs) compared to untreated mice (6%) by flow cytometry. We also observed increased senescent DCCs (82%, p<0.0001 compared to untreated mice, 37%) by a β-gal assay. BM-DCCs in HER2-DC1 vaccinated mice had reduced expression of Ki-67 compared to untreated mice. Multicolor flow cytometry demonstrated elevated levels of CD4 T cells (2 fold increase) and CD8 T cells (1 fold increase) in the bone marrow after HER2-DC1 vaccination compared to untreated mice. Importantly, accumulation of CD4 T cells (5 fold increase), CD8 T cells (19 fold increase) and B cells (100 fold increase) was observed in the mammary glands of HER2-DC1 vaccinated mice with strong anti-HER2 Th1 immune responses. Notably, HER2-DC1 vaccine led to an increased in the M1 macrophage phenotype (3 fold increase) and decreased M2 type (8 fold decrease) at the tumor site. Treatment of DCCs with Th1 cytokines, IFN-γ or TNF-α significantly induced senescence (76.3%, p<0.0001) in cultured DCCs compared to untreated cells (26%) in vitro. These results describe the novel role of HER2-DC1 vaccine in targeting DCCs and a possible role in prevention of metastasis and recurrence. Citation Format: Ganesan Ramamoorthi, Krithika Kodumudi, Colin Synder, William Dominguez-Viqueira, Scott Kidd, Shari Pilon-Thomas, Brian Czerniecki. HER2 peptide pulsed dendritic cell vaccine induce senescence and eliminates disseminated cancer cells in a preventive model of transgenic HER2/neu breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1451.

Safety of nivolumab in combination with dendritic cell vaccines in recurrent high-grade glioma.

e13526 Background: Recurrence of high-grade glioma (HGG) (WHO grade III-IV) is a nearly universal phenomenon and necessitates the development of new therapeutic modalities. Two possible immunotherapeutic modalities are checkpoint blockade with agents such as nivolumab, a blocking antibody against the inhibitory checkpoint programmed cell death-1 (PD-1), and dendritic cell (DC) vaccination. We have shown in phase 1 and 2 trials that DC vaccination against the glioblastoma (GBM)-associated antigen human cytomegalovirus pp65-lysosomal-associated membrane protein (CMVpp65) is safe and possesses potential benefit. We hypothesized that nivolumab-induced immune checkpoint blockade could enhance efficacy of DC vaccination. Therefore, we undertook a phase 1 study to evaluate safety of nivolumab in combination with CMVpp65 mRNA pulsed DC vaccination in subjects with first or second recurrence of resectable HGG. Methods: We performed a phase 1, single-center, randomized study of nivolumab alone versus nivolumab + DC vaccination prior to planned surgical resection for both groups. We administered nivolumab 3 mg/kg IV q2weeks for 8 weeks followed by surgery and planned continuation of nivolumab. For the group receiving nivolumab + DC vaccination, we administered 3 vaccines before surgical resection with both groups receiving 5 planned post-resection DC vaccines. Primary endpoint was safety assessment using NCI-CTCAE 4.03. Results: We enrolled 6 subjects (4: GBM, 1: anaplastic astrocytoma, 1: anaplastic oligodendroglioma) with 3 receiving nivolumab alone and 3 receiving nivolumab + DC vaccination. Age range was 45-63 years subjects. We documented similar adverse events in both groups with most common grade 1-2 toxicities being fatigue (2 subjects, nivolumab alone) and thrombocytopenia (2 subjects, nivolumab + DC vaccine). Grade 4 toxicities included wound infection (2 subjects, nivolumab + DC vaccine) and meningitis (1 subject, nivolumab + DC vaccine). While we designed the study to enroll 66 subjects, we terminated the study early in light of CheckMate 143 phase III data showing nivolumab did not improve overall survival in recurrent GBM. Conclusions: Safety of nivolumab + DC vaccination in recurrent HGG is similar to nivolumab alone. Continued evaluation of new therapeutics including immunotherapy is underway for this patient population. Clinical trial information: NCT02529072.

Dendritic cell-based vaccine for pancreatic cancer in Japan.

"Vaccell" is a dendritic cell (DC)-based cancer vaccine which has been established in Japan. The DCs play central roles in deciding the direction of host immune reactions as well as antigen presentation. We have demonstrated that DCs treated with a streptococcal immune adjuvant OK-432, produce interleukin-12, induce Th1-dominant state, and elicit anti-tumor effects, more powerful than those treated with the known DC-maturating factors. We therefore decided to mature DCs by the OK-432 for making an effective DC vaccine, Vaccell. The 255 patients with inoperable pancreatic cancer who received standard chemotherapy combined with DC vaccines, were analyzed retrospectively. Survival time of the patients with positive delayed type hypersensitivity (DTH) skin reaction was significantly prolonged as compared with that of the patients with negative DTH. The findings strongly suggest that there may be "Responders" for the DC vaccine in advanced pancreatic cancer patients. We next conducted a small-scale prospective clinical study. In this trial, we pulsed HLA class II-restricted WT1 peptide (WT1-II) in addition to HLA class I-restricted peptide (WT1-I) into the DCs. Survival of the patients received WT1-I and -II pulsed DC vaccine was significantly extended as compared to that of the patients received DCs pulsed with WT1-I or WT1-II alone. Furthermore, WT1-specific DTH positive patients showed significantly improved the overall survival as well as progression-free survival as compared to the DTH negative patients. The activation of antigen-specific immune responses by DC vaccine in combination with standard chemotherapy may be associated with a good clinical outcome in advanced pancreatic cancer. We are now planning a pivotal study of the Vaccell in appropriate protocols in Japan.

Shikonin-enhanced cell immunogenicity of tumor vaccine is mediated by the differential effects of DAMP components

BackgroundThe tumor cell lysate-pulsed, dendritic cell (DC)-based cancer vaccine approaches are being actively evaluated for application to cancer immunotherapy, hopefully at a personalized medicine base. There is apparently an emerging technical problem however, the lack of highly efficacious potency in activation of patient’s DCs for T-cell priming and the associated process for presenting tumor immunogenicity.MethodsOne strategy to address this is to consider the manipulation of the tumor immunogenic cells death (ICD) complex ex-vivo for maximal activation of DC efficacy. In our previous study we showed that phytochemical shikonin (SK) can drastically enhance ICD activity in mouse tumor cells treated ex-vivo, and the resultant tumor cell lysate (TCL) can effectively augment such SK-TCL pulsed DC vaccine activity in vivo in anti-tumor activities. In this study, we investigated the specifics and the multi-functional effects of various damaged associated molecular pattern (DAMP) components of the ICD complex for their participation, roles and potential cross talks in activating DCs, as measured by five different functional assays.ResultsAmong three DAMPs tested, HSP70 and CRT mediate a key role in SK-TCL-induced DC immunity for both CD4+ and CD8+ T cell proliferations in vitro. HSP70 is the most important component, followed by CRT, then HMGB1 in facilitating DC immunity on suppressing metastasis of mouse 4 T1 mammary tumors and prolonging survival in test mice. Only HSP70, but not CRT or HMGB1, is effective for the suppression of both granulocytic and monocytic MDSC populations in vivo. Both HSP70 and HMGB1, but not CRT, are essential in activating the expression of three key ICD molecules-associated receptors on test DCs. Each of the three test ICD proteins can exhibit a distinguishable pattern in stimulating the expression of four key chemokines in test DCs.ConclusionOur findings on the differential roles or effect of various ICD components in activating vaccinated DCs may help formulate new strategies for future cancer vaccine designs.

Dendritic cell vaccine treatment of advanced de novo colorectal cancer in renal transplant patients.

Objective: The clinical outcome, especial the immunologic responses to cancer and graft, of dendritic cell (DC) vaccine in the treatment of advanced de novo colorectal cancer (CRC) in renal transplant patients was investigated in this study. Materials and Methods: 7 patients were received 1 cycle tumor lysate pulsed autologous DC vaccine. The positive cell-mediated cytotoxicity responses to DC vaccine against CRC cell in two out of 7 patients were seen by delayed type hypersensitivity (DTH) test. The positive cell-mediated cytotoxicity responses to DC vaccine against normal kidney cell in all 7 patients were not seen by DTH tests and no notable change of renal function during and after vaccination. Conclusions: DC vaccine has emerged as a promising new strategy in the treatment of advanced de novo CRC in renal transplant patients and DC vaccines have become an attractive therapeutic option, developing immune responses specific against CRC cell, achieving clinical efficacy without graft failure.

Abstract LB-163: A phase I trial investigating apoptosis induction with tumor necrosis factor or radiation alone prior to intratumoral injection of autologous dendritic cells in patients with locally advanced or low volume metastatic pancreatic cancer.

Abstract The purpose of this trial was to determine the safety, feasibility and efficacy of intra-tumoral injection of an autologous dendritic cell (DC) based vaccine following apoptosis induction with a tumor necrosis factor expressing adenovector (TNF) or low dose radiation therapy (XRT). Methods: Between August 2006 and August 2011, 24 patients with locally advanced (n= 17) or low-volume metastatic (n=7) pancreatic cancer were enrolled to receive either: TNF on day 1 followed by vector activating XRT (2 Gy/d on days 1-3) and then an autologous, KLH pulsed DC vaccine (50M cells, day 4) for 3 weeks; or, XRT (1.9 Gy/d on days1-4) followed by DC vaccine (50M cells, day 5) for 3 weeks. Feasibility endpoints included our ability to produce the vaccine and the subject's ability to complete all phases of the protocol. Serious adverse events (SAE) were recorded to establish safety. Efficacy was established by radiographic and biochemical tumor response, progression free (PFS) and overall survival (OS). Results: All but 2 patients completed the protocol (92%). One patient died prior to initiation of treatment (not included in survival analysis) and one disenrolled during treatment due to deep venous thrombosis. 50 of 66 (76%) total vaccines produced contained greater than 50M DC. There was no vaccine related toxicity. In the TNF group, there were 19 SAEs including one death. In the XRT group, there were 33 SAEs mostly characterized by pain, nausea, dehydration and vomiting. Two (4%) SAEs led to hospital admission, one for duodenal bleeding and one for bacteremia. Tumor response favored the radiation group as did survival. (table) Conclusions: DC based vaccines are feasible and safe in patients with advanced pancreatic cancer. Apoptosis induction using TNF, though less complicated, imparted no survival advantage over radiation alone and may have provided some disadvantage. Efficacy O.S. (mos) P.F.S. (mos) Stable or partial response (%) Stable or decreased Ca19-9(%) TNF (n = 15) 5.8±2.05 4.7±2.17 60 62 XRT (n = 8) 8.7±3.48 6.9±3.79 75 100 Total 6.9±2.92 5.4±2.96 65 76 Citation Format: Emmanuel E. Zervos, James J. Mule, Denise Brigham, William Janssen, Jennifer Cooper, Alexander S. Rosemurgy. A phase I trial investigating apoptosis induction with tumor necrosis factor or radiation alone prior to intratumoral injection of autologous dendritic cells in patients with locally advanced or low volume metastatic pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-163. doi:10.1158/1538-7445.AM2013-LB-163

Comparison of Glioma-associated Antigen Peptide-loaded Versus Autologous Tumor Lysate-loaded Dendritic Cell Vaccination in Malignant Glioma Patients

Dendritic cell (DC) vaccination is emerging as a promising therapeutic option for malignant glioma patients. However, the optimal antigen formulation for loading these cells has yet to be established. The objective of this study was to compare the safety, feasibility, and immune responses of malignant glioma patients on 2 different DC vaccination protocols. Twenty-eight patients were treated with autologous tumor lysate (ATL)-pulsed DC vaccination, whereas 6 patients were treated with glioma-associated antigen (GAA) peptide-pulsed DCs. Safety, toxicity, feasibility, and correlative immune monitoring assay results were compared between patients on each trial. Because of HLA subtype restrictions on the GAA-DC trial, 6/15 screened patients were eligible for treatment, whereas 28/32 patients passed eligibility screening for the ATL-DC trial. Elevated frequencies of activated natural killer cells were observed in the peripheral blood from GAA-DC patients compared with the ATL-DC patients. In addition, a significant correlation was observed between decreased regulatory T lymphocyte (Treg) ratios (postvaccination/prevaccination) and overall survival (P = 0.004) in patients on both trials. In fact, Treg ratios were independently prognostic for overall survival in these patients, whereas tumor pathology was not in multivariate analyses. In conclusion, these results suggest that ATL-DC vaccination is associated with wider patient eligibility compared with GAA-DC vaccination. Decreased postvaccination/prevaccination Treg ratios and decreased frequencies of activated natural killer cells were associated with prolonged survival in patients from both trials, suggesting that these lymphocyte subsets may be relevant immune monitoring endpoints for immunotherapy protocols in malignant glioma patients.

Immunotherapy by autologous dendritic cell vaccine in patients with advanced HCC

Dendritic cells (DCs) could be used as potential cellular adjuvant for the production of specific tumor vaccines. Our study was aimed to evaluate the safety and efficacy of autologous pulsed DC vaccine in advanced hepatocellular carcinoma (HCC) patients in comparison with supportive treatment. Thirty patients with advanced HCC not suitable for radical or loco-regional therapies were enrolled. Patients were divided into 2 groups, group I consisted of 15 patients received I.D vaccination with mature autologous DCs pulsed ex vivo with a liver tumor cell line lysate. Group II (control group, no. 15) received supportive treatment. One hundred and 4 ml of venous blood were obtained from each patient to generate DCs. DCs were identified by CD80, CD83, CD86 and HLA-DR expressions using flow cytometry. Follow up at 3, and 6 months post injection by clinical, radiological and laboratory assessment was done. Improvement in overall survival was observed. Partial radiological response was obtained in 2 patients (13.3 %), stable course in 9 patients (60 %) and 4 patients (26.7 %) showed progressive disease (died at 4 months post-injection). Both CD8(+) T cells and serum interferon gamma were elevated after DCs injection. Autologous DC vaccination in advanced HCC patients is safe and well tolerated.

Correlation of survival with tumor antigen expression in patients with newly diagnosed glioblastoma receiving a multi-epitope pulsed dendritic cell vaccine.

2087 Background: This study evaluated the safety and immune responses to an autologous dendritic cell vaccine pulsed with class I peptides from tumor associated antigens (TAA) expressed on gliomas and overexpressed in their cancer stem cell population (ICT-107). These TAA epitodes AIM-2. TRP-2, HER2 and AIM-2, are also overexpressed on glioblastoma multiforme (GBM) cancer stem cells. Methods: TAA epitopes included HER2, TRP-2, gp100, MAGE-1, IL13Rα2, and AIM-2. HLA-A1 and/or HLA-A2 positive glioblastoma (GBM) patients with gross total resection were eligible. Mononuclear cells from leukapheresis were differentiated into dendritic cells, pulsed with TAA peptides, and administered intradermally three times at two-week intervals in the axilla region after a standard treatment with concurrent temozolomide (TMZ) and radiation therapy for newly diagnosed (ND-GBM). Results: Twenty-one patients were enrolled with 17 ND-GBM and three recurrent GBM patients and one brainstem glioma. Immune response data on 15 newly diagnosed patients showed 33% responders. TAA expression by qRT-PCR showed all patient tumors expressed at least three TAA with 75% expressing all six. Correlations of increased PFS and quantitative expression of MAGE1, AIM-2, gp100 and HER2 were observed. A decrease or absence of CD133 expression was seen in five patients who underwent a second resection. As of February 1, 2012, six of 16 ND-GBM patients showed no evidence of tumor recurrence (44-63 months). Median progressive free survival (PFS) in newly diagnosed patients was 16.9 months with a two-year PFS rate was 43.8% (95%CI,19.8-66.0 ). The median overall survival rate (OS) was 38.4 months and a two-year OS was 80.3% (95%CI,58.6-96.7). Conclusions: Expression of four ICT-107 targeted antigens in the pre-vaccine tumors correlated with prolonged overall survival and PFS in ND-GBM patients. The goal of targeting tumor antigens highly expressed on glioblastoma cancer stem cells is supported by the observation of decreased or absent CD133 expression in the recurrent areas of gadolinium-enhanced tumor.

Lack of T-cell responses following autologous tumour lysate pulsed dendritic cell vaccination, in patients with relapsed osteosarcoma

Immunotherapy using autologous dendritic cell (DC) vaccination has not been systematically evaluated in osteosarcoma. We therefore conducted a phase I trial to assess feasibility, safety and tumour-specific immune responses in patients with relapsed disease. Of 13 recruited patients with relapsed osteosarcoma, 12 received 3 weekly vaccines of autologous DCs matured with autologous tumour lysate and keyhole limpet haemocyanin (KLH), to a maximum of 6 vaccinations. An additional 3 paediatric patients afflicted with other tumour types and with relapsed disease received vaccines generated with identical methodology. Immune responses were assessed using an ELISpot assay for the detection of interferon gamma, whilst interleukin-2 and granzyme B were additionally assessed in cases where interferon-γ responses were induced. In total 61 vaccines, of homogeneous maturation phenotype and viability, were administered with no significant toxicity. Only in 2 out of 12 treated osteosarcoma cases was there an induction of specific T-cell immune response to the tumour, whilst a strong but non-specific immune response was induced in 1 further osteosarcoma patient. Immune response against KLH was induced in only 3 out of 12 osteosarcoma patients. In contrast, three additional non-osteosarcoma patients showed significant T-cell responses to vaccine. We have shown the strategy of DC vaccination in relapsed osteosarcoma is safe and feasible. However, significant anti-tumour responses were induced in only 2 out of 12 vaccinated patients with no evidence of clinical benefit. Comparison of results with identically treated control patients suggests that osteosarcoma patients might be relatively insensitive to DC-based vaccine treatments.

HER‐2 pulsed dendritic cell vaccine can eliminate HER‐2 expression and impact ductal carcinoma in situ

HER-2/neu overexpression plays a critical role in breast cancer development, and its expression in ductal carcinoma in situ (DCIS) is associated with development of invasive breast cancer. A vaccine targeting HER-2/neu expression in DCIS may initiate immunity against invasive cancer. A HER-2/neu dendritic cell vaccine was administered to 27 patients with HER-2/neu-overexpressing DCIS. The HER-2/neu vaccine was administered before surgical resection, and pre- and postvaccination analysis was conducted to assess clinical results. At surgery, 5 of 27 (18.5%) vaccinated subjects had no evidence of remaining disease, whereas among 22 subjects with residual DCIS, HER-2/neu expression was eradicated in 11 (50%). When comparing estrogen receptor (ER)(neg) with ER(pos) DCIS lesions, vaccination was more effective in hormone-independent DCIS. After vaccination, no residual DCIS was found in 40% of ER(neg) subjects compared with 5.9% in ER(pos) subjects. Sustained HER-2/neu expression was found in 10% of ER(neg) subjects compared with 47.1% in ER(pos) subjects (P = .04). Postvaccination phenotypes were significantly different between ER(pos) and ER(neg) subjects (P = .01), with 7 of 16 (43.8%) initially presenting with ER(pos) HER-2/neu(pos) luminal B phenotype finishing with the ER(pos) HER-2/neu(neg) luminal A phenotype, and 3 of 6 (50%) with the ER(neg) HER-2/neu(pos) phenotype changing to the ER(neg) HER-2/neu(neg) phenotype. Results suggest that vaccination against HER-2/neu is safe and well tolerated and induces decline and/or eradication of HER-2/neu expression. These findings warrant further exploration of HER-2/neu vaccination in estrogen-independent breast cancer and highlight the need to target additional tumor-associated antigens and pathways.

Enhanced anti-tumor immunity by superantigen-pulsed dendritic cells.

Staphylococcal enterotoxins A (SEA) and B (SEB) are classical models of superantigens (SAg), which induce potent T-cell-stimulating activity by forming complexes with MHC class II molecules on antigen-presenting cells. This large-scale activation of T-cells is accompanied by increased production of cytokines such as interferon-γ (IFN-γ). Additionally, as we previously reported, IFN-γ-producing CD8(+) T cells act as "helper cells," supporting the ability of dendritic cells to produce interleukin-12 (IL-12)p70. Here, we show that DC pulsed with SAg promote the enhancement of anti-tumor immunity. Murine bone marrow-derived dendritic cells (DC) were pulsed with OVA(257-264) (SIINFEKL), which is an H-2Kb target epitope of EG7 [ovalbumin (OVA)-expressing EL4] cell lines, in the presence of SEA and SEB and were subcutaneously injected into naïve C57BL/6 mice. SAg plus OVA(257-264)-pulsed DC vaccine strongly enhanced peptide-specific CD8(+) T cells exhibiting OVA(257-264)-specific cytotoxic activity and IFN-γ production, leading to the induction of protective immunity against EG7 tumors. Furthermore, cyclophosphamide (CY) added to SAg plus tumor-antigens (OVA(257-264), tumor lysate, or TRP-2) pulsed DC immunization markedly enhanced tumor-specific T-cell expansion and had a significant therapeutic effect against various tumors (EG7, 2LL, and B16). Superantigens are potential candidates for enhancing tumor immunity in DC vaccines.

Gene Expression Profile Correlates with T-Cell Infiltration and Relative Survival in Glioblastoma Patients Vaccinated with Dendritic Cell Immunotherapy

To assess the feasibility, safety, and toxicity of autologous tumor lysate-pulsed dendritic cell (DC) vaccination and toll-like receptor (TLR) agonists in patients with newly diagnosed and recurrent glioblastoma. Clinical and immune responses were monitored and correlated with tumor gene expression profiles. Twenty-three patients with glioblastoma (WHO grade IV) were enrolled in this dose-escalation study and received three biweekly injections of glioma lysate-pulsed DCs followed by booster vaccinations with either imiquimod or poly-ICLC adjuvant every 3 months until tumor progression. Gene expression profiling, immunohistochemistry, FACS, and cytokine bead arrays were performed on patient tumors and peripheral blood mononuclear cells. DC vaccinations are safe and not associated with any dose-limiting toxicity. The median overall survival from the time of initial surgical diagnosis of glioblastoma was 31.4 months, with a 1-, 2-, and 3-year survival rate of 91%, 55%, and 47%, respectively. Patients whose tumors had mesenchymal gene expression signatures exhibited increased survival following DC vaccination compared with historic controls of the same genetic subtype. Tumor samples with a mesenchymal gene expression signature had a higher number of CD3(+) and CD8(+) tumor-infiltrating lymphocytes compared with glioblastomas of other gene expression signatures (P = 0.006). Autologous tumor lysate-pulsed DC vaccination in conjunction with TLR agonists is safe as adjuvant therapy in newly diagnosed and recurrent glioblastoma patients. Our results suggest that the mesenchymal gene expression profile may identify an immunogenic subgroup of glioblastoma that may be more responsive to immune-based therapies.

A Randomized Trial ofEx vivoCD40L Activation of a Dendritic Cell Vaccine in Colorectal Cancer Patients: Tumor-Specific Immune Responses Are Associated with Improved Survival

To determine whether an autologous dendritic cell (DC) vaccine could induce antitumor immune responses in patients after resection of colorectal cancer metastases and whether these responses could be enhanced by activating DCs with CD40L. Twenty-six patients who had undergone resection of colorectal metastases were treated with intranodal injections of an autologous tumor lysate- and control protein [keyhole limpet hemocyanin (KLH)]-pulsed DC vaccine. Patients were randomized to receive DCs that had been either activated or not activated with CD40L. All patients were followed for a minimum of 5.5 years. Immunization induced an autologous tumor-specific T-cell proliferative or IFNγ enzyme-linked immunospot response in 15 of 24 assessable patients (63%) and a tumor-specific DTH response in 61%. Patients with evidence of a vaccine-induced, tumor-specific T-cell proliferative or IFNγ response 1 week after vaccination had a markedly better recurrence-free survival (RFS) at 5 years (63% versus 18%, P = 0.037) than nonresponders. In contrast, no association was observed between induction of KLH-specific immune responses and RFS. CD40L maturation induced CD86 and CD83 expression on DCs but had no effect on immune responses or RFS. Adjuvant treatment of patients after resection of colorectal metastases with an autologous tumor lysate-pulsed, DC vaccine-induced, tumor-specific immune responses in a high proportion of patients. There was an association between induction of tumor-specific immune responses and RFS. Activation of this DC vaccine with CD40L did not lead to increased immune responses.

Highlights of This Issue

Kwon and colleagues explored the role of the nuclear protein HMGB2 in hepatocellular carcinoma (HCC). The mRNA and protein expression levels of HMGB2 were significantly elevated in HCC and increased expression of HMGB2 was associated with poor prognosis. Further, silencing of HMGB2 by siRNA decreased HCC cell survival and overexpression of HMGB2 suppressed cisplatin- and etoposide-induced apoptotic cell death in vitro. These findings suggest that HMGB2 expression has biological and clinical implications as an important prognostic factor associated with antiapoptotic pathways in HCC.The EGFR T790M mutation and MET amplification are the two main molecular mechanisms responsible for acquired resistance to EGFR tyrosine kinase inhibitors (TKI) in patients with non–small cell lung carcinoma (NSCLC). To explore their relationship, Suda and colleagues analyzed lung cancer cell lines and gefitinib-refractory tumors from autopsy patients. They found that these two resistance mechanisms exhibited a reciprocal and complementary relationship, with a MET amplification of four-fold or greater and EGFR T790M being almost mutually exclusive. These findings have implications in both the prevention and therapy of secondary resistance to EGFR TKIs in NSCLC.The 5T4 antigen is expressed on the surface of most solid tumors. Amato and colleagues conducted a phase III study in which modified vaccinia Ankara (MVA) was used to deliver 5T4 (MVA-5T4) to patients with renal cancer. MVA-5T4 was well tolerated, but did not result in significantly enhanced survival relative to controls. Exploratory analyses showed that a 5T4 antibody response was associated with enhanced survival and that several pretreatment hematologic factors may identify patients who receive significant benefit from MVA- 5T4. These observations could lead to the development of an early biomarker of efficacy and help to select patients most likely to benefit from treatment.There has been limited study of dendritic cell (DC) vaccines in the adjuvant setting after resection of metastatic tumors, in general, and colorectal cancer, in particular. Barth and colleagues conducted a clinical trial in which patients were treated with a DC vaccine in the adjuvant setting after resection of metastatic disease. They found that an autologous tumor lysate–pulsed DC vaccine could induce immune responses against autologous tumor in over 60% of patients. Patients who developed an autologous tumor– specific immune response had improved recurrence-free survival.