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Press Coverage from Racial Survival Disparity in Head and Neck Cancer Results from Low Prevalence of Human Papillomavirus Infection in Black Oropharyngeal Cancer Patients

Perspective on This Article from Racial Survival Disparity in Head and Neck Cancer Results from Low Prevalence of Human Papillomavirus Infection in Black Oropharyngeal Cancer Patients

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Purpose: We have previously reported that many types of tumors can induce changes in human T cells that lead to the acquisition of suppressive function and phenotypic alterations resembling those found in senescent T cells. In the present study, we find a role for interleukin 7 (IL-7) in protecting T cells from these changes and further define involved signaling pathways.Experimental Design: We evaluated the ability of IL-7 treatment to prevent the gain of suppressive function and phenotypic alterations in human T cells after a short coculture with tumor cells in vitro. We then used inhibitors of components of the phosphoinositide 3-kinase (PI3K)/AKT pathway and short interfering RNA knockdown of Mcl-1 and Bim to evaluate the role of these signaling pathways in IL-7 protection.Results: We found that IL-7 inhibits CD27/CD28 loss and maintains proliferative capacity, IL-2 production, and reduced suppressive function. The protective ability of IL-7 depended on activation of the PI3K/AKT pathway, which inhibited activation of glycogen synthase kinase 3β, which, in turn, prevented the phosphorylation and loss of Mcl-1. We further showed a key role for Mcl-1 in that its knockdown or inhibition abrogated the effects of IL-7. In addition, knockdown of the Mcl-1 binding partner and proapoptotic protein Bim protected T cells from these dysfunctional alterations.Conclusion: These observations confirm the role for Bcl-2 family members in cytokine signaling and suggest that IL-7 treatment in combination with other immunotherapies could lead to new clinical strategies to maintain normal T-cell function and reduce tumor-induced generation of dysfunctional and suppressor T cells. Clin Cancer Res; 17(15); 4975–86. ©2011 AACR.

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Purpose: Myeloma-directed cellular immune responses after autologous stem cell transplantation (ASCT) may reduce relapse rates. We studied whether coinjecting the TLR-3 agonist and vaccine adjuvant Poly-ICLC with a MAGE-A3 peptide vaccine was safe and would elicit a high frequency of vaccine-directed immune responses when combined with vaccine-primed and costimulated autologous T cells.Experimental Design: In a phase II clinical trial (NCT01245673), we evaluated the safety and activity of ex vivo expanded autologous T cells primed in vivo using a MAGE-A3 multipeptide vaccine (compound GL-0817) combined with Poly-ICLC (Hiltonol), granulocyte macrophage colony-stimulating factor (GM-CSF) ± montanide. Twenty-seven patients with active and/or high-risk myeloma received autografts followed by anti-CD3/anti-CD28–costimulated autologous T cells, accompanied by MAGE-A3 peptide immunizations before T-cell collection and five times after ASCT. Immune responses to the vaccine were evaluated by cytokine production (all patients), dextramer binding to CD8+ T cells, and ELISA performed serially after transplant.Results: T-cell infusions were well tolerated, whereas vaccine injection site reactions occurred in >90% of patients. Two of nine patients who received montanide developed sterile abscesses; however, this did not occur in the 18 patients who did not receive montanide. Dextramer staining demonstrated MAGE-A3–specific CD8 T cells in 7 of 8 evaluable HLA-A2+ patients (88%), whereas vaccine-specific cytokine-producing T cells were generated in 19 of 25 patients (76%). Antibody responses developed in 7 of 9 patients (78%) who received montanide and only weakly in 2 of 18 patients (11%) who did not. The 2-year overall survival was 74% [95% confidence interval (CI), 54%–100%] and 2-year event-free survival was 56% (95% CI, 37%–85%).Conclusions: A high frequency of vaccine-specific T-cell responses were generated after transplant by combining costimulated autologous T cells with a Poly-ICLC/GM-CSF–primed MAGE-A3 vaccine. Clin Cancer Res; 20(5); 1355–65. ©2013 AACR.

Supplementary References from Considerations for the Clinical Application of Chimeric Antigen Receptor T Cells: Observations from a Recombinant DNA Advisory Committee Symposium Held June 15, 2010

T cells that are genetically modified to express single-chain chimeric antigen receptors (CAR) have shown promise in early cancer immunotherapy clinical trials. Unfortunately, 2 recent deaths in cancer patients treated with CAR T cells have created some uncertainty on how to best mitigate patient risk, while continuing to advance this very promising therapeutic avenue. In order to address these concerns, the Recombinant DNA Advisory Committee (RAC) held a symposium, the objectives of which were to first review the reported treatment-associated toxicities and, second, to discuss methods for improving safety and efficacy. This report highlights the issues raised as part of this discussion, with a specific focus on protocols infusing CAR T cells. Because this was not a consensus conference, the opinions described should not be construed to represent those of any individual RAC member, the RAC as a body, conference participants, the National Institutes of Health, or the U.S. Food and Drug Administration. Cancer Res; 71(9); 3175–81. ©2011 AACR.

Supplementary Tables 1-5 from Considerations for the Clinical Application of Chimeric Antigen Receptor T Cells: Observations from a Recombinant DNA Advisory Committee Symposium Held June 15, 2010

Monoclonal antibodies (mAbs) that target immune co-signaling pathways have the potential to enable immune mediated tumor eradication. While early adoption of these agents for the treatment of advanced squamous cell carcinoma of the head and neck (SCCHN) has produced some astounding clinical successes, the majority of patients fail to respond to therapy. The purpose of this review is to first provide a broad overview of the immuno-oncology (I-O) landscape and to then focus on the current status of mAb-based I-O (mAb:I-O) for the treatment of SCCHN, with particular attention to the development of strategies for improving treatment responses.

Fibrolamellar carcinoma (FLC) is a rare liver malignancy that has no known cure. Novel therapies for FLC are urgently needed to improve patient outcomes. The key genetic event in FLC tumorigenesis is a highly conserved gene fusion between the first exon of DNAJB1 and the last nine exons of PRKACA. This fusion gene is present in all FLC tumors, and more than 90% of patients express fusion proteins with identical amino acid sequences. Genetic mutations like this gene fusion can serve as important therapeutic vulnerabilities, in part because they may be processed and presented on the surface of tumor cells as neoantigens that can activate an anti-tumor T cell response. The purpose of our study was to test the hypothesis that DNAJB1-PRKACA fusion neoantigens could elicit T cell responses against FLC and serve as targets for novel immunotherapies. Spatial transcriptomic analyses of human FLC tumor samples indicated that CD8+ T cells could infiltrate these tumors, but often expressed markers of dysfunction and exhaustion, such as TOX. Nevertheless, we successfully expanded tumor-infiltrating T cells from FLC ex vivo and used intracellular cytokine staining (ICS) to identify a subset of FLC patient T cells that produced IFNγ and TNFα in response to stimulation with a fusion neoantigen. We used both peptide-MHC tetramer staining and functional response after stimulation to identify T cells in FLC patients and healthy donors that recognize fusion neoantigens. We then determined the paired T cell receptor (TCR) sequences using single-cell sequencing and expressed the TCRs in primary human T cells to test their potential utility in TCR-engineered immunotherapies. We validated the specificity and functionality of these TCRs using peptide-MHC tetramer staining, ICS, and in vitro cytotoxicity assays on the xCelligence and Berkeley Lights Lightning platforms. Primary T cells expressing fusion-specific TCRs bound to their cognate peptide-MHC tetramer, produced multiple cytokines in response to stimulation with their cognate fusion peptide, and specifically killed fusion-presenting target cells in vitro. Ongoing experiments will test whether T cells expressing these fusion-specific TCRs can control growth of fusion-presenting tumors in vivo. Collectively, these studies have defined the first reported fusion-specific T cell response in FLC, as well as fusion-specific TCRs that hold promise for use in adoptive T cell therapies. Our spatial transcriptomic analyses have also begun to illuminate the immune microenvironment in FLC and will inform future efforts to develop immunotherapies for this disease. Citation Format: Allison M. Kirk, Ching-Heng Chou, Jeremy Chase Crawford, Walid Awad, E. Kaitlynn Allen, Xiaoyu Zhang, Anthony E. Zamora, Scott E. Strome, Paul G. Thomas. Characterization of CD8 T cell responses to DNAJB1-PRKACA fusion neoantigens in fibrolamellar carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1383.

Fibrolamellar carcinoma (FLC) is an often-lethal liver malignancy of adolescents and young adults. No systemic therapies are currently approved for FLC, so novel treatments are needed to improve patient outcomes. A promising therapeutic vulnerability in FLC is a highly-conserved gene fusion between DNAJB1 and PRKACA. The resultant fusion protein is identical in more than 90% of patients, making it a potentially ideal neoantigen target for T cell-based immunotherapy. The goal of our study was to test if DNAJB1-PRKACA neoantigens could elicit T cell responses and serve as targets for immunotherapy. Spatial transcriptomic analyses of FLC tumor tissue indicated that CD8 T cells could infiltrate FLC tumors, but expressed exhaustion markers such as TOX. Nevertheless, we expanded T cells from an FLC patient tumor ex vivo and detected T cells that produced IFNγ and TNFα in response to stimulation with a fusion neoantigen. We then used functional response after peptide stimulation or peptide-MHC tetramer staining to identify fusion-specific T cell receptors (TCRs) in both FLC patients and healthy donors. We expressed these TCRs in primary human T cells and found that cells expressing fusion-specific TCRs bound to their cognate tetramer and produced IFNγ, TNFα, and IL-2 in response to stimulation with their cognate peptide. TCR-expressing cells also specifically killed target cells presenting their cognate fusion peptide in vitro. Ongoing experiments will test if cells expressing these TCRs can control growth of fusion-expressing tumors in vivo. Together, these studies have defined the first reported fusion-specific T cell response in an FLC patient, as well as fusion-specific TCRs that hold promise for development in adoptive T cell therapies. Supported by grants from NIH (R01 AI136514, F31 CA254423) and The Mark Foundation for Cancer Research (Aspire Award)

The success of Intravenous Immunoglobulin in treating autoimmune and inflammatory processes such as immune thrombocytopenia purpura and Kawasaki disease has led to renewed interest in developing recombinant molecules capable of recapitulating these therapeutic effects. The anti-inflammatory properties of IVIG are, in part, due to the Fc region of the IgG molecule, which interacts with activating or inhibitory Fcγ receptors (FcγRs), the neonatal Fc Receptor, non-canonical FcRs expressed by immune cells and complement proteins. In most cases, Fc interactions with these cognate receptors are dependent upon avidity—avidity which naturally occurs when polyclonal antibodies recognize unique antigens on a given target. The functional consequences of these avid interactions include antibody dependent cell-mediated cytotoxicity, antibody dependent cell phagocytosis, degranulation, direct killing, and/or complement activation—all of which are associated with long-term immunomodulatory effects. Many of these immunologic effects can be recapitulated using recombinant or non-recombinant approaches to induce Fc multimerization, affording the potential to develop a new class of therapeutics. In this review, we discuss the history of tolerance induction by immune complexes that has led to the therapeutic development of artificial Fc bearing immune aggregates and recombinant Fc multimers. The contribution of structure, aggregation and N-glycosylation to human IgG: FcγR interactions and the functional effect(s) of these interactions are reviewed. Understanding the mechanisms by which Fc multimers induce tolerance and attempts to engineer Fc multimers to target specific FcγRs and/or specific effector functions in autoimmune disorders is explored in detail.

There is a lack of effective targeted therapies for the treatment of complement dependent diseases. We developed two recombinant Fc multimers, G207 and G211, with limited ability to interact with low/moderate affinity FcγRs, but with high avidity for C1q. These drugs effectively inhibited complement dependent cytotoxicity (CDC) in vitro, and prevented the deposition of C1q, C3b and MAC, on the surface of Ab-opsonized cells. Importantly, these inhibitory effects were both C1q dependent and independent. In order to determine the biologic relevance of our findings, we evaluated the clinical efficacy of these drugs in three different animal models, acute RBC hemolysis, anti-Thy-1 nephritis and passive Heymann's nephropathy (PHN), in which disease pathophysiology relies preferentially on complement activation. While G207 was protective in the anti-Thy-1 nephritis and PHN models, G211 was protective in all of the models tested and could effectively treat PHN. In the anti-Thy-1 nephritis model, G211 prevented the characteristic histologic changes associated with the disease and limited glomerular deposition of C3. Collectively, these data suggest that “complement preferential” Fc multimers offer a novel approach to the treatment of complement mediated diseases.

GL-2045 is a recombinant human immunoglobulin G1 (IgG1)-based Fc multimer designed to recapitulate the anti-inflammatory activities of intravenous immunoglobulin (IVIG) on the innate and adaptive immune responses. We used functional in vitro studies to determine if GL-2045 could mimic the modulatory activity of IVIG on complement activation. GL-2045, at log-order lower concentrations than heat-aggregated IgG (HAGG) and IVIG, protected antibody-opsonized cells from complement-dependent cytotoxicity. These protective effects were completely mediated by the higher order multimer fractions of GL-2045 and were partially dependent upon sequestration of C1q. Exposure of serum to GL-2045 and, to a lesser extent, IVIG, resulted in high levels of C4a, limited levels of C3a, and no C5a. In contrast, HAGG induced high levels of C4a, C3a, and C5a. The means by which GL-2045 governed complement activation was dependent on its ability to augment the function of factor H, alone and in combination with factor I, to indirectly limit the alternative form of C3 convertase, with resultant increases in the anti-inflammatory molecule, the "inactive" form of C3b, called iC3b. Although IVIG, like GL-2045, potentiated factor H function, it also directly inhibited the alternative form of C3 convertase. Our findings help elucidate how IVIG, GL-2045, and HAGG regulate complement function. Furthermore, the capacity of GL-2045 to sequester C1q and augment factor H activity, in combination with its ability to generate activation-induced immunomodulatory complement split products, such as iC3b, make it a viable drug candidate for the treatment of diverse complement-mediated diseases.

Recent advances have permitted successful therapeutic targeting of the immune system in head and neck squamous cell carcinoma (HNSCC). These new immunotherapeutic targets and agents are being rapidly adopted by the oncologic community and hold considerable promise. The National Cancer Institute sponsored a Clinical Trials Planning Meeting to address the issue of how to further investigate the use of immunotherapy in patients with HNSCC. The goals of the meeting were to consider phase 2 or 3 trial designs primarily in 3 different patient populations: those with previously untreated, human papillomavirus-initiated oropharyngeal cancers; those with previously untreated, human papillomavirus-negative HNSCC; and those with recurrent/metastatic HNSCC. In addition, a separate committee was formed to develop integrative biomarkers for the clinical trials. The meeting started with an overview of key immune components and principles related to HNSCC, including immunosurveillance and immune escape. Four clinical trial concepts were developed at the meeting integrating different immunotherapies with existing standards of care. These designs were presented for implementation by the head and neck committees of the National Cancer Institute-funded National Clinical Trials Network. This article summarizes the proceedings of this Clinical Trials Planning Meeting, the purpose of which was to facilitate the rigorous development and design of randomized phase 2 and 3 immunotherapeutic trials in patients with HNSCC. Although reviews usually are published immediately after the meeting is held, this report is unique because there are now tangible clinical trial designs that have been funded and put into practice and the studies are being activated to accrual. Cancer 2017;123:1259-1271. © 2016 American Cancer Society.

We developed a fully recombinant anti-CD20 protein derived from cDNA encoding one Fab domain, two IgG1 Fc regions, the IgG2 hinge, and an isoleucine zipper. This protein, called GB4542, contained both the homodimer and higher-order multimers. Binding studies revealed that GB4542 preferentially bound CD20+ cells yet also recognized CD20−FcγR+ PBMC. In contrast, a control mAb containing the identical Fab region, GB4500, failed to bind CD20−FcγR+ PBMC. Consistent with these findings, interactions between GB4542 and the canonical FcγRs had substantially lower KD values than correlate interfaces between GB4500 and these receptors. At low concentrations, GB4542 showed enhanced Ab-dependent cellular cytotoxicity, Ab-dependent cellular phagocytosis, and complement-dependent cytotoxicity compared with GB4500. However, at higher concentrations, an Fc analog of GB4542 inhibited anti-CD20 mAb–mediated B cell clearance through direct blocking of both Fc–FcγR interactions and C1q deposition on target cells. Furthermore, the higher-order multimer fraction of GB4542 demonstrated greater binding avidity with the canonical FcγRs and was associated with inhibitory effects observed in Ab-dependent cellular phagocytosis and complement-dependent cytotoxicity assays. These data suggest that GB4542 might have utility in the treatment of autoimmune diseases by combining both mAb-mediated B cell depletion and multimerized Fc-mediated tolerogenic effects.

The methods of cell detachment influence phenotype and function of human macrophages cultured in vitro. However, comparative studies defining the influence of cell detachment techniques on secondary characterization of M1 or M2 polarized macrophages are largely absent from the literature. In this study we evaluated the impact of trypsin, accutase, EDTA, PBS, and cell scraping on: A. cell recovery, B. phenotype and C. function of in vitro polarized macrophages. Our data demonstrate that while exposure to trypsin or accutase yields highly efficient recovery of viable cells, such chemical cleavage results in loss of select M2 cell surface markers with correlative changes in cell function. In contrast, phenotype and function are maintained following detachment by EDTA on ice. Our data suggest that seemingly "trivial" changes in methodologies for macrophage detachment induce both variable and profound changes on cell phenotype and function which can dramatically impact the results of polarization experiments.

Given the heightened interest in manipulation of co-signaling cascades for cancer immunotherapy, we sought to determine how/whether tumors decorated with therapeutic monoclonal antibodies (mAbs) impact the expression of co-signaling molecules on human NK cells. Stimulation of NK cells with aggregated IgG1 resulted in the upregulation of HAVCR2 – the gene encoding T-cell immunoglobulin and mucin-containing domain (Tim)-3 – known to be involved in the induction of peripheral T cell tolerance. This upregulation of HAVCR2 was recapitulated at the protein level, following NK cell stimulation by either mAb opsonized tumors, recombinant human IgG1 Fc multimer, and/or non-Fc stimuli e.g. IL-12/IL-18. The patterns of Tim-3 expression were temporally distinct from the FcR mediated induction of the co-signaling molecule, 4-1BB (CD137), with Tim-3 increases observed twenty minutes following exposure to Fc multimers and remaining at high levels for at least six hours, while increases in CD137 expression were first observed at the four-hour time point. Importantly, these Tim-3+ NK cells were functionally diverse, as evidenced by the fact that their ability to produce IFN-γ in response to an NK cell responsive tumor was strictly dependent upon the stimuli employed for Tim-3 induction. These data suggest that Tim-3 upregulation is the common end-result of NK cell activation by a variety of unique and overlapping stimuli and is not an independent marker of NK cell exhaustion. Furthermore, our observations potentially explain the diverse functionality attributed to Tim-3+ NK cells and should be considered prior to use of anti-Tim-3 inhibitory mAbs for cancer immunotherapy.

BACKGROUND We sought to evaluate intratumor heterogeneity in squamous cell carcinoma of the oral cavity (OCC) and specifically determine the effect of physical separation and histologic differentiation within the same tumor. METHODS We performed whole exome sequencing on five biopsy sites-two from well-differentiated, two from poorly differentiated regions, and one from normal parenchyma-from five primary OCC specimens. RESULTS We found high levels of intratumor heterogeneity and, in four primary tumors, identified only 0 to 2 identical mutations in all subsites. We found that the heterogeneity inversely correlated with physical separation and that pairs of well-differentiated samples were more similar to each other than analogous poorly differentiated specimens. Only TP53 mutations, but not other purported "driver mutations" in head and neck squamous cell carcinoma, were found in multiple biopsy sites. CONCLUSION These data highlight the challenges to characterization of the mutational landscape of OCC with single site biopsy and have implications for personalized medicine.

The antiinflammatory effects of i.v. Ig (IVIG) in the treatment of autoimmune disease are due, in part, to the Fc fragments of Ig aggregates. In order to capitalize on the known antiinflammatory and tolerogenic properties of Ig Fc aggregates, we created a recombinant human IgG1 Fc multimer, GL-2045. In vitro, GL-2045 demonstrated high-avidity binding to Fc receptors, blocked the binding of circulating immune complexes from patients with rheumatoid arthritis to human Fcγ receptors (FcγRs), and inhibited antibody-mediated phagocytosis at log order-lower concentrations than IVIG. In vivo, administration of GL-2045 conferred partial protection against antibody-mediated platelet loss in a murine immune thrombocytopenic purpura (ITP) model. GL-2045 also suppressed disease activity in a therapeutic model of murine collagen-induced arthritis (CIA), which was associated with reduced circulating levels of IL-6. Furthermore, GL-2045 administration to nonhuman primates (NHPs) transiently increased systemic levels of the antiinflammatory cytokines IL-10 and IL-1RA, reduced the proinflammatory cytokine IL-8, and decreased surface expression of CD14 and HLA-DR on monocytes. These findings demonstrate the immunomodulatory properties of GL-2045 and suggest that it has potential as a treatment for autoimmune and inflammatory diseases, as a recombinant alternative to IVIG.

Background Racial outcome disparities have been observed in head and neck squamous cell carcinoma (HNSCC) with diminished survival for black patients compared with white patients. Methods We retrospectively analyzed 1318 patients with primary HNSCC treated at the University of Maryland Greenebaum Cancer Center (UMGCC) from 2000 to 2010. Results Of all the patients, 65.9% were white, 30.7% were black, and 3.3% were of other races. Black patients were less likely to present with oral cavity cancer, and more likely to present with laryngeal or hypopharyngeal cancers. White patients were more likely to have early stage disease, especially in the oral cavity. Black race was independently associated with worse overall survival (OS) in the entire cohort. Black patients had a significantly worse OS among oral cavity and oropharyngeal cancers, with the largest disparity in oropharyngeal cancer. However, in multivariate analysis, race was only still significant in oropharyngeal cancer. Conclusion We observed differences by race in distribution of disease site, stage, and OS. Survival disparity in the entire cohort was driven mostly by differences among oropharyngeal cancer.

We conducted a phase I dose escalation study to evaluate the safety and immunologic response to peptide immunomodulatory vaccines GL-0810 (HPV16) and GL-0817 (MAGE-A3) in HPV16 and MAGE-A3-positive RM–SCCHN patients, respectively. Three dose levels (500, 1,000, and 1,500 µg) of GL-0810 or GL-0817 with adjuvants Montanide (1.2 ml) and GM-CSF (100 µg/m2) were administered subcutaneously q2 weeks for a total of four vaccinations in HPV16 and MAGE-A3-positive RM–SCCHN patients, respectively. Nine and seven patients were enrolled in the HPV16 and MAGE-A3 cohorts, respectively. No dose-limiting toxicities were observed, and toxicity was predominantly local and grade 1 (erythema, pain, and itching at the injection site). In those patients who received all four vaccinations, 80 % (4/5) of the HPV16 cohort and 67 % (4/6) of the MAGE-A3 cohort developed antigen-specific T cell and antibody responses to the vaccine. Significant concordance between T cell and antibody responses was observed for both groups. No clear dose–response correlation was seen. All patients progressed by RECIST at first repeat imaging, except for one patient in the MAGE-A3 500 µg cohort who had stable disease for 10.5 months. The median PFS and OS for the MAGE-A3 cohorts were 79 and 183 days, respectively, and for the HPV16 cohort 80 and 196 days, respectively. GL-0810 and GL-0817 were well tolerated in patients with RM–SCCHN with T cell and antibody responses observed in the majority of patients who received all four vaccinations.

Agonistic monoclonal antibodies (mAbs) directed against the co-signaling molecule CD137 (4-1BB) elicit potent anti-tumor immunity in mice. This anti-tumor immunity has traditionally been thought to result from the ability of the Fab portion of anti-CD137 to function as an analog for CD137L. Although binding of CD137 by anti-CD137 mAbs has the potential to cross-link the Fc fragments, enabling Fc engagement of low to moderate affinity Fc gamma receptors (FcγR), the relative import of such Fc-FcγR interactions in mediating anti-CD137 associated anti-tumor immunity is unknown. We studied the ability of a rat anti-mouse CD137 mAb (2A) to mediate the anti-tumor response against the EL4E7 lymphoma in WT and FcγR(-/-) strains. 2A-treated FcRγ(-/-) mice had improved anti-tumor immunity against EL4E7, which could be completely recapitulated in FcγRIII(-/-) animals. These improved anti-tumor responses were associated with increased splenic CD8β T cell and dendritic cell (DC) populations. Furthermore, there was an increase in the number of DCs expressing high levels of the CD40, CD80, and CD86 molecules that are associated with more effective antigen presentation. Our results demonstrate an unexpected inhibitory role for FcγRIII in the anti-tumor function of anti-CD137 and underscore the need to consider antibody isotype when engineering therapeutic mAbs.

Tumour antigen targeted antibodies (mAbs) can induce natural killer (NK) cells to kill tumours through antibody dependent cellular cytotoxicity (ADCC) upon engagement of NK cell expressed FcγRIIIa. FcγRIIIa polymorphisms partially dictate the potency of the ADCC response. The high affinity FcγRIIIa-158-valine (V) polymorphism is associated with more potent ADCC response than the low affinity FcγRIIIa-158-phenylalanine (F) polymorphism. Because approximately 45% of patients are homozygous for the FcγRIIIa-158-F polymorphism (FF genotype), their ability to mount ADCC is impaired. We investigated whether a novel mAb capable of binding multiple antigen specific targets and engaging multiple low affinity FcγRIIIa receptors could further enhance ADCC against colon cancer in vitro. Specifically, we generated a novel anti-epidermal growth factor receptor (EGFR) antibody (termed a stradobody) consisting of an unmodified Fab sequence and two Immunoglobulin G, subclass 1 (IgG1) Fc domains separated by an isoleucine zipper domain and the 12 amino-acid IgG2 hinge. The stradobody framework induced multimerisation and was associated with increased binding to the EGFR and FcγRIIIa. From a functional perspective, when compared to an unmodified anti-EGFR mAb with a sequence identical to cetuximab (a commercially available anti-EGFR mAb), stradobodies significantly enhanced ADCC. These effects were observed using both KRAS wild type HT29 and KRAS mutant SW480 colon cancer cells as targets, and by NK cells obtained from healthy donors and a cohort of patients with colon cancer. These data suggest that high avidity cross-linking of multiple tumour surface antigens and multiple NK cell associated FcγRIIIa molecules can enhance ADCC and partially overcome impaired ADCC by FF genotype individuals in vitro.

Recurrent solid malignancies are often refractory to standard therapies. Although adoptive T cell transfer may benefit select individuals, the majority of patients succumb to their disease. To address this important clinical dilemma, we developed a mouse melanoma model in which initial regression of advanced disease was followed by tumor recurrence. During recurrence, Foxp3+ tumor-specific CD4+ T cells became PD-1+ and represented >60% of the tumor-specific CD4+ T cells in the host. Concomitantly, tumor-specific CD4+ T effector cells showed traits of chronic exhaustion, as evidenced by their high expression of the PD-1, TIM-3, 2B4, TIGIT, and LAG-3 inhibitory molecules. Although blockade of the PD-1/PD-L1 pathway with anti–PD-L1 Abs or depletion of tumor-specific regulatory T cells (Tregs) alone failed to reverse tumor recurrence, the combination of PD-L1 blockade with tumor-specific Treg depletion effectively mediated disease regression. Furthermore, blockade with a combination of anti–PD-L1 and anti–LAG-3 Abs overcame the requirement to deplete tumor-specific Tregs. In contrast, successful treatment of primary melanoma with adoptive cell therapy required only Treg depletion or Ab therapy, underscoring the differences in the characteristics of treatment between primary and relapsing cancer. These data highlight the need for preclinical development of combined immunotherapy approaches specifically targeting recurrent disease.

Essentials Fc-fusion increases a therapeutic's half-life, but FcγR interactions may impact immunogenicity. Species-specific Fc-FcγR interactions allow for mechanistic in vivo studies using mouse models. Fc fusion modulates the immune response to factor IX in hemophilia B mice by eliciting Th1 bias. This model could inform future studies of IgE-associated anaphylaxis in hemophilia B patients. SummaryBackground Fc fusion is a platform technology used to increase the circulating half-life of protein and peptide therapeutics. However, there are potential immunological consequences with this approach, such as changes in the molecule's immunogenicity as well as possible interactions with a repertoire of Fc receptors (FcR) that can modulate immune responses. Objectives/Methods Using a mouse hemophilia B (HB) model, we compared the immune responses to infusions of recombinant human factor IX (hFIX) and hFIX fused to mouse IgG2a-Fc (hFIX-mFc). The mFc was employed to allow species-specific Fc–FcγR interactions. Results Although treatment with hFIX-mFc altered the early development of anti-FIX IgG, no significant differences in anti-FIX antibody titers were observed at the end of the treatment regimen (5 weeks) or upon anamnestic response (5 months). However, treatment with hFIX-mFc elicited higher FIX-neutralizing antibody levels and resulted in reduced IgE titers compared with the hFIX-treated group. Additionally, differences in plasma cytokine levels and in vitro CD4+ T-cell responses suggest that whereas hFIX treatment triggered a Th2-biased immune response, hFIX-mFc treatment induced Th1-biased CD4+ T cells. We also show that hFIX-mFc bound to soluble FcγRs and engaged with FcγRs on different cell types, which may impact antigen presentation. Conclusions These studies provide a model system to study how Fc-fusion proteins may affect immune mechanisms. We used this model to demonstrate a plausible mechanism by which Fc fusion may modulate the IgE response to hFIX. This model may be appropriate for investigating the rare but severe IgE-mediated anaphylaxis reaction to hFIX infusions in HB patients.

We review the current clinical knowledge surrounding one of the most promising immune checkpoint pathways currently investigated in head and neck squamous cell carcinoma patients, programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2). We review ongoing clinical trials and associated clinical responses observed with targeting the receptor, PD-1, and its ligand, PD-L1. A recent phase III clinical trial (Checkmate 141) demonstrated an improved overall survival in head and neck cancer patients treated with anti-PD-1 monotherapy as compared to standard of care for recurrent and/or metastatic disease, which raises questions on how best to incorporate immunotherapy in the context of standard of care. We discuss biomarkers of response to this class of novel drugs, which is an area of active investigation. Lastly, we project future directions in the field wherein understanding how the Fc portions of the various monoclonal antibodies may impact their clinical efficacy as well as discuss areas where our next advances may take place, such as combination strategies.

The tumor volume has been established as a significant predictor of outcomes among patients with head-and-neck cancer undergoing radiotherapy alone. The present study attempted to add to the existing data on tumor volume as a prognostic factor among patients undergoing chemoradiotherapy.A total of 78 patients who had undergone definitive chemoradiotherapy for Stage III-IV squamous cell cancer of the hypopharynx, oropharynx, and larynx were identified. The primary tumor volumes were calculated from the treatment planning computed tomography scans, and these were correlated to the survival and tumor control data obtained from the retrospective analysis.The interval to progression correlated with the primary tumor volume (p = .007). The critical cutoff point for the tumor volume was identified as 35 cm(3), and patients with a tumor volume35 cm(3) had a significantly better prognosis than those with a tumor volume35 cm(3) at 5 years (43% vs. 71%, p = .010). Longer survival was also correlated with smaller primary tumor volumes (p = .022). Similarly, patients with a primary tumor volume35 cm(3) had a better prognosis in terms of both progression-free survival (61% vs. 33%, p = .004) and overall survival (84% vs. 41%, p =.001). On multivariate analysis, the primary tumor volume was the best predictor of recurrence (hazard ratio 4.7, 95% confidence interval 1.9-11.6; p = .001) and survival (hazard ratio 10.0, 95% confidence interval 2.9-35.1; p =.001). In contrast, the T stage and N stage were not significant factors. Analysis of variance revealed that tumors with locoregional failure were on average 21.6 cm(3) larger than tumors without locoregional failure (p = .028) and 27.1-cm(3) larger than tumors that recurred as distant metastases (p = .020).The results of our study have shown that the primary tumor volume is a significant prognostic factor in patients with advanced cancer of the head and neck undergoing definitive chemoradiotherapy and correlated with the treatment outcomes better than the T or N stage.

Background. We performed a pilot study using Trojan vaccines in patients with advanced squamous cell carcinoma of the head and neck (SCCHN). These vaccines are composed of HLA-I and HLA-II restricted melanoma antigen E (MAGE)-A3 or human papillomavirus (HPV)-16 derived peptides, joined by furin-cleavable linkers, and linked to a "penetrin'' peptide sequence derived from HIV- TAT. Thirty-one patients with SCCHN were screened for the trial and 5 were enrolled. Methods. Enrolled patients were treated with 300 lg of Trojan peptide supplemented with Montanide and granulocyte-macrophage colony- stimulating factor (GM-CSF) at 4-week intervals for up to 4 injections. Results. Following vaccination, peripheral blood mononuclear cells (PBMCs) from 4 of 5 patients recognized both the full Trojan constructs and constituent HLA-II peptides, whereas responses to HLA-I restricted peptides were less pronounced. Conclusion. This treatment regimen seems to have acceptable toxicity and elicits measurable systemic immune responses against HLA-II restricted epitopes in a subset of patients with advanced SCCHN. V C 2012 Wiley Periodicals, Inc. Head Neck 34: 1734-1746, 2012

Erythropoiesis, the production of red blood cells, must be tightly controlled to ensure adequate oxygen delivery to tissues without causing thrombosis or stroke. Control of physiologic and pathologic erythropoiesis is dependent predominantly on erythropoietin (EPO), the expression of which is regulated by hypoxia-inducible factor (HIF) activity in response to low oxygen tension. Accumulating evidence indicates that oxygen-independent mediators, including inflammatory stimuli, cytokines, and growth factors, also upregulate HIF activity, but it is unclear whether these signals also result in EPO production and erythropoiesis in vivo. Here, we found that signaling through herpesvirus entry mediator (HVEM), a molecule of the TNF receptor superfamily, promoted HIF-1α activity in the kidney and subsequently facilitated renal Epo production and erythropoiesis in vivo under normoxic conditions. This Epo upregulation was mediated by increased production of NO by renal macrophages. Hvem-deficient mice displayed impaired Epo expression and aggravated anemia in response to erythropoietic stress. These data reveal that HVEM signaling functions to promote HIF-1α activity and Epo production, and thus to regulate erythropoiesis. Furthermore, our findings suggest that this molecular mechanism could represent a therapeutic target for Epo-responsive diseases, including anemia.

Genetic engineering of tumor cells to express immune-stimulatory molecules, including cytokines and co-stimulatory ligands, is a promising approach to generate highly efficient cancer vaccines. The co-signaling molecule, LIGHT, is particularly well suited for use in vaccine development as it delivers a potent co-stimulatory signal through the Herpes virus entry mediator (HVEM) receptor on T cells and facilitates tumor-specific T cell immunity. However, because LIGHT binds two additional receptors, lymphotoxin β receptor and Decoy receptor 3, there are significant concerns that tumor-associated LIGHT results in both unexpected adverse events and interference with the ability of the vaccine to enhance antitumor immunity. In order to overcome these problems, we generated tumor cells expressing the single-chain variable fragment (scFv) of anti-HVEM agonistic mAb on the cell surface. Tumor cells expressing anti-HVEM scFv induce a potent proliferation and cytokine production of co-cultured T cells. Inoculation of anti-HVEM scFv-expressing tumor results in a spontaneous tumor regression in CD4+ and CD8+ T cell-dependent fashion, associated with the induction of tumor-specific long-term memory. Stimulation of HVEM and 4-1BB co-stimulatory signals by anti-HVEM scFv-expressing tumor vaccine combined with anti-4-1BB mAb shows synergistic effects which achieve regression of pre-established tumor and T cell memory specific to parental tumor. Taken in concert, our data suggest that genetic engineering of tumor cells to selectively potentiate the HVEM signaling pathway is a promising antitumor vaccine therapy.

Purpose: We have previously reported that many types of tumors can induce changes in human T cells that lead to the acquisition of suppressive function and phenotypic alterations resembling those found in senescent T cells. In the present study, we find a role for interleukin 7 (IL-7) in protecting T cells from these changes and further define involved signaling pathways. Experimental Design: We evaluated the ability of IL-7 treatment to prevent the gain of suppressive function and phenotypic alterations in human T cells after a short coculture with tumor cells in vitro. We then used inhibitors of components of the phosphoinositide 3-kinase (PI3K)/AKT pathway and short interfering RNA knockdown of Mcl-1 and Bim to evaluate the role of these signaling pathways in IL-7 protection. Results: We found that IL-7 inhibits CD27/CD28 loss and maintains proliferative capacity, IL-2 production, and reduced suppressive function. The protective ability of IL-7 depended on activation of the PI3K/AKT pathway, which inhibited activation of glycogen synthase kinase 3β, which, in turn, prevented the phosphorylation and loss of Mcl-1. We further showed a key role for Mcl-1 in that its knockdown or inhibition abrogated the effects of IL-7. In addition, knockdown of the Mcl-1 binding partner and proapoptotic protein Bim protected T cells from these dysfunctional alterations. Conclusion: These observations confirm the role for Bcl-2 family members in cytokine signaling and suggest that IL-7 treatment in combination with other immunotherapies could lead to new clinical strategies to maintain normal T-cell function and reduce tumor-induced generation of dysfunctional and suppressor T cells. Clin Cancer Res; 17(15); 4975–86. ©2011 AACR.

T cells that are genetically modified to express single-chain chimeric antigen receptors (CAR) have shown promise in early cancer immunotherapy clinical trials. Unfortunately, 2 recent deaths in cancer patients treated with CAR T cells have created some uncertainty on how to best mitigate patient risk, while continuing to advance this very promising therapeutic avenue. In order to address these concerns, the Recombinant DNA Advisory Committee (RAC) held a symposium, the objectives of which were to first review the reported treatment-associated toxicities and, second, to discuss methods for improving safety and efficacy. This report highlights the issues raised as part of this discussion, with a specific focus on protocols infusing CAR T cells. Because this was not a consensus conference, the opinions described should not be construed to represent those of any individual RAC member, the RAC as a body, conference participants, the National Institutes of Health, or the U.S. Food and Drug Administration. Cancer Res; 71(9); 3175–81. ©2011 AACR.

T-cell tolerance is the central program that prevents harmful immune responses against self-antigens, in which inhibitory PD-1 signal given by B7-H1 interaction plays an important role. Recent studies demonstrated that B7-H1 binds CD80 besides PD-1, and B7-H1/CD80 interaction also delivers inhibitory signals in T cells. However, a role of B7-H1/CD80 signals in regulation of T-cell tolerance has yet to be explored. We report here that attenuation of B7-H1/CD80 signals by treatment with anti–B7-H1 monoclonal antibody, which specifically blocks B7-H1/CD80 but not B7-H1/PD-1, enhanced T-cell expansion and prevented T-cell anergy induction. In addition, B7-H1/CD80 blockade restored Ag responsiveness in the previously anergized T cells. Experiments using B7-H1 or CD80-deficient T cells indicated that an inhibitory signal through CD80, but not B7-H1, on T cells is responsible in part for these effects. Consistently, CD80 expression was detected on anergic T cells and further up-regulated when they were re-exposed to the antigen (Ag). Finally, blockade of B7-H1/CD80 interaction prevented oral tolerance induction and restored T-cell responsiveness to Ag previously tolerized by oral administration. Taken together, our findings demonstrate that the B7-H1/CD80 pathway is a crucial regulator in the induction and maintenance of T-cell tolerance.

CD137 (4-1BB)-mediated costimulation plays an important role in directing the fate of Ag-stimulated T cells and NK cells, yet the role of CD137 in mediating B cell function is unknown. We found that CD137 is expressed in vitro on anti-Ig–stimulated peripheral blood B cells and in vivo on tonsillar B cells with an activated phenotype. In vitro CD137 expression is enhanced by CD40 stimulation and IFN-γ and is inhibited by IL-4, -10, and -21. The expression of CD137 on activated human B cells is functionally relevant because engagement with its ligand at the time of activation stimulates B cell proliferation, enhances B cell survival, and induces secretion of TNF-α and -β. Our study suggests that CD137 costimulation may play a role in defining the fate of Ag-stimulated human B cells.

We have a long-term interest in the connectivity between autoimmunity and tumor rejection. However, outside of the melanocyte/melanoma paradigm, little is known about whether autoimmune responses to normal tissue can induce rejection of tumors of the same histologic type. Here, we induced direct, pathogen-like cytotoxicity to the normal pancreas in association with the immune adjuvant heat shock protein 70. In sharp contrast to our studies with a similar approach for the treatment of prostate cancer, inflammatory killing of the normal pancreas induced a Th1-like, anti-self-response to pancreatic antigens, which was rapidly suppressed by a concomitant suppressive regulatory T cell (Treg) response. Interestingly, even when Treg cells were depleted, the Th1-like response was insufficient to induce significant ongoing autoimmunity. However, the Th1-like response to antigens expressed in the pancreas at the time of damage was sufficient to induce rejection of tumors expressing either a foreign (ova) antigen or fully syngeneic tumor antigens (on Panc02 tumor cells), provided that Treg were depleted before inflammatory killing of the normal pancreas. Taken together, these data indicate that profound differences exist between the immunoprotective mechanisms in place between different tissues (pancreas and prostate) in their response to pathogen-like damage. Moreover, they also show that, although multiple layers of immunologic safeguards are in place to prevent the development of severe autoimmune consequences in the pancreas (in contrast to the prostate), tumor rejection responses can still be decoupled from pathologic autoimmune responses in vivo, which may provide novel insights into the immunotherapeutic treatment of pancreatic cancer. [Cancer Res 2009;69(19):7767–74]

Antibody based manipulation of the CD137 (4-1BB) co-signaling pathway is an attractive option for the treatment of cancer and autoimmune disease. We developed a chimeric anti-human CD137 monoclonal antibody (GG) and characterized its function. As a component of planned preclinical studies, we evaluated the binding of GG to activated peripheral blood mononuclear cells (PBMCs) from cynomolgus macaque and baboon against human. Interestingly, GG only recognized human CD137, while a commercial anti-CD137 mAb (4B4-1), recognized activated PBMCs from both human and non-human primates (NHP). Subsequent analysis revealed that the amino acid sequence of CD137 is largely conserved between primate species ( approximately 95% identical), with the extracellular domain differing by only 9-10 amino acids. Based on these data, we generated mutant constructs in the extracellular domain, replacing NHP with human CD137 sequences, and identified 3 amino acids critical for GG binding. These residues are likely part of a conformational epitope, as a peptide spanning this region is unable to block mAb binding. These data demonstrate that subtle sequence variations of defined co-stimulatory molecules amongst primate species can be employed as a strategy for mapping residues necessary for antibody binding to conformational epitopes.

To protect viral particles from neutralization, sequestration, nonspecific adhesion, and mislocalization following systemic delivery, we have previously exploited the natural tumor-homing properties of antigen-specific CD8+ T cells. Thus, OT-I T cells, preloaded in vitro with the oncolytic vesicular stomatitis virus (VSV), can deliver virus to established B16ova tumors to generate significantly better therapy than that achievable with OT-I T cells, or systemically delivered VSV, alone. Here, we demonstrate that preconditioning immune-competent mice with Treg depletion and interleukin-2 (IL-2), before adoptive T-cell therapy with OT-I T cells loaded with VSV, leads to further highly significant increases in antitumor therapy. Therapy was associated with antitumor immune memory, but with no detectable toxicities associated with IL-2, Treg depletion, or systemic dissemination of the oncolytic virus. Efficacy was contributed by multiple factors, including improved persistence of T cells; enhanced delivery of VSV to tumors; increased persistence of OT-I cells in vivo resulting from tumor oncolysis; and activation of NK cells, which acquire potent antitumor and proviral activities. By controlling the levels of virus loaded onto the OT-I cells, adoptive therapy was still effective in mice preimmune to the virus, indicating that therapy with virus-loaded T cells may be useful even in virus-immune patients. Taken together, our data show that it is possible to combine adoptive T-cell therapy, with biological therapy (Treg depletion+IL-2), and VSV virotherapy, to treat established tumors under conditions where none of the individual modalities alone is successful.