Checkpoint Blockade Agents Research Articles

Abstract A030: Epigenetic immune modulation by entinostat in breast cancer: Correlative analysis of ENCORE 301 trial

Abstract Background: Entinostat, a class I HDAC inhibitor (HDACi), has shown promising activity in ENCORE 301, a randomized, placebo-controlled, phase II trial of entinostat + exemestane (EE) vs. exemestane + placebo (EP) in advanced hormone receptor-positive breast cancer progressed on nonsteroidal aromatase inhibitors. ENCORE 301 met the primary progression free survival endpoint and showed a median 8.3-month improvement in the overall survival (OS) exploratory endpoint for the EE arm. Emerging preclinical work suggests that entinostat has immunomodulatory effects and can eradicate modestly immunogenic mouse tumors in combination with immune checkpoint blockade agents via reduction of circulating myeloid-derived suppressor cells (MDSC). Based on these data, we conducted an analysis of immune subsets in blood samples from ENCORE 301 breast cancer patients. Method: Blood was collected from a subset of 49 patients (27 EE and 22 EP) representative of the 130 patients enrolled in ENCORE 301 on cycle 1 day 1 (C1D1; pre-treatment), C1D2, C1D8, and C1D15 for biomarker analysis. Of these, 34 patient samples (20 EE and 14 EP) were analyzed for circulating immune subsets. The percent change in subsets at C1D15 vs. baseline was assessed based on the following surface markers: Lin-MDSC (lin; CD3, CD19, CD56)-HLA-DR-CD11b+CD33+), granulocytic MDSC (CD14-CD11b+CD33+), monocytic MDSC (Lin-HLA-DR-CD11b+CD33+CD14+), immature MDSC (Lin-HLA-DR-CD11b+CD33+CD14-), CD8+ T-cells (CD4-CD8+), Foxp3-CD4+ T-cells (CD8-CD4+Foxp3-), and Tregs (CD4+CD8-CD25hiFoxp3+). Monocytes were analyzed for three populations: CD14+, CD14+HLA-DRhi, and CD14+HLA-DRlow/negative. In addition, PD-1, CTLA-4, and TIM-3 were measured on T-cell subsets, and CD40 was measured on MDSCs. Results: In line with preclinical data, we observed a significant reduction in granulocytic MDSC (-14.67% vs. +20.56%, p 0.029) and monocytic MDSC (-62.3% vs. +1.97%, p 0.002) in EE. Entinostat did not alter immature MDSC levels (-20.9% vs. -15.0%, p 0.93) suggesting a downstream effect of entinostat on MDSC subsets. Interestingly, CD40, a costimulatory receptor required for MDSC-mediated immune suppression was significantly down-regulated in all MDSC subsets except granulocytic MDSC where a downward trend was observed. Entinostat did not significantly impact the ratio of CD8+ T-cells per CD4+ T-cells or per Tregs or alter expression of CTLA4, PD-1, or TIM3 on T-cell subsets. Reduced expression of HLA-DR on monocytes has been associated with poor prognosis in cancer. Consistent with entinostat-mediated immunomodulatory effects, a significant increase in the number of HLA-DR+ monocytes (34.1% vs. -11.38%, p 0.0004) and level of HLA-DR expression on monocytes (16.3% vs. -4.7%; p 0.015) was observed. Conclusion: Data with entinostat combined with exemestane in ENCORE 301 provide the first evidence of HDACi-mediated reduction of immunosuppressive MDSCs and increased immunocompetent CD14+HLA-DRhi monocytes in patients. These findings may explain the improved OS seen with EE in ENCORE 301 and provide strong rationale for planned combination studies of entinostat with immune checkpoint blockade agents. Citation Format: Peter Ordentlich, Min-Jung Lee, Yusuke Tomita, Sunmin Lee, Saori Tomita, Scott Cruickshank, Saranya Chumsri, Jane B. Trepel. Epigenetic immune modulation by entinostat in breast cancer: Correlative analysis of ENCORE 301 trial. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A030.

Abstract C104: TAS-121, a highly potent and mutant-specific EGFR inhibitor, modulates the immune system, resulting in anti-tumor immune responses

Abstract Background: TAS-121 is one of the 3rd generation EGFR TKI, which specifically inhibits mutant EGFRs, and it leads to high cellular selectivity and potent antitumor activity in various in vivo models. TAS-121 is being investigated in patients with non-small cell lung cancer (NSCLC) harboring not only active mutant EGFR, but also acquired resistance mutation T790M in phase I study. immune-related events observed during treatment with TAS-121 in preclinical and clinical studies suggested that TAS-121 could modulate the immune system and, consequently, might partially contribute to anti-tumor effect. To prove this hypothesis, we examined the immuno-modulating potential of TAS-121 using MLR assay, TCR stimulation assay and in vivo syngeneic tumor models. Material and methods: Immune cell proliferation and cytokine production were confirmed by the CFSE dilution using flow cytometry, and ELISA assay, respectively. Anti-tumor immune response was analyzed in syngeneic models bearing with MC38 murine colon carcinoma cell line. Results: TAS-121 strongly induced the proliferation of CD4 T cells and CD8 T cells as well as stimulating cytokine production. Other EGFR TKIs, including 1st generation to 3rd generation agents, didn't show these effects. TAS-121 inhibited the growth of syngeneic tumor, MC38 in vivo, while no growth inhibition was observed in vitro. These data demonstrate that TAS-121 can induce anti-tumor immune responses. Conclusions: These findings suggest that TAS-121 could specifically modulate the immune system including T cells, leading to the anti-tumor immune responses. Therefore, TAS-121 has a unique profile among the 3rd generation EGFR-TKI. Considering this immune-modulating profile, combination with immune checkpoint blockade agent such as anti-PD1 monoclonal antibody might be beneficial for NSCLC patients harboring mutant EGFR. Citation Format: Satoshi Fukaya, Yoshimi Aoyagi, Masanori Katoh, Kimihiro Itoh, Toshihiro Shibutani, Nozomu Tanaka, Tomonori Haruma, Akihiro Hashimoto, Kazutaka Miyadera, Kenichi Matsuo, Yoshikazu Iwasawa, Teruhiro Utsugi, Kazuhiko Yonekura. TAS-121, a highly potent and mutant-specific EGFR inhibitor, modulates the immune system, resulting in anti-tumor immune responses. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C104.

Abstract B67: A big role in tumor immune microenvironment of a small non-coding RNA: microRNA-200

Abstract Immunosuppression of tumor-infiltrating lymphocytes (TIL) is a common feature of advanced epithelial tumors, but its biological basis has remained obscure. In addition, anti-PD-1/PD-L1 treatment has produced encouraging clinical responses, but it is still unclear which patients are likely to benefit. Thus, successful therapeutic translation will require a thorough understanding of mechanisms of treatment resistance and predictive biomarkers to select patients. Using multiple lung cancer mouse models (spontaneous and transplant models), we demonstrate a molecular link between epithelial-to-mesenchymal transition (EMT) and intra-tumoral CD8+ T cell immunosuppression, two key drivers of malignant tumor progression. We show that microRNA-200 (miR-200), a cell-autonomous suppressor of EMT and metastasis, targets PD-L1, a checkpoint inhibitor of CD8+ T cell immunity. Moreover, ZEB1, an EMT activator and transcriptional repressor of miR-200, relieves miR-200 repression of PD-L1 on tumor cells, leading to CD8+TIL dysfunction and metastasis. These findings were further supported by robust correlations between the EMT score, miR-200 levels and PD-L1 expression in multiple human lung cancer datasets: The Cancer Genome Atlas (TCGA) lung adenocarcinoma dataset and the Profiling of Resistance patterns and Oncogenic Signaling Pathways in Evaluation of Cancers of the Thorax (PROSPECT) project at MD Anderson Cancer Center. In addition to revealing a link between EMT and T cell dysfunction, these findings also show that ZEB1 promotes metastasis through a heretofore unappreciated cell non-autonomous mechanism, and they suggest that subgroups of patients in whom malignant progression is driven by EMT activators may respond to treatment with PD-L1 antagonists. Our data also suggest that EMT represents an important biomarker to select the patients who may benefit from immune checkpoint blockade agents and other immunotherapies in lung cancer and possibly a broader range of other cancers. Citation Format: Limo Chen, Sangeeta Goswami, Xiaohui Yi, Lauren Byers, Lixia Diao, Jonathon Roybal, Christin Ungewiss, David Peng, Jing Wang, Ignacio Wistuba, Lieping Chen, Stephen Ullrich, John Heymach, Jonathan Kurie, Xiao-Feng Qin, Don Gibbons. A big role in tumor immune microenvironment of a small non-coding RNA: microRNA-200. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr B67.

Clinicopathologic Features Associated With Human Papillomavirus/p16 in Patients With Metastatic Squamous Cell Carcinoma of the Anal Canal.

The incidence of anal carcinoma in the U.S. continues to increase steadily, and infection with the human papillomavirus (HPV) is an established risk factor for the development of anal carcinoma. However, the clinicopathologic characteristics of patients with metastatic squamous cell carcinoma of the anal canal according to HPV status have not yet been defined. The records of patients treated for metastatic squamous cell carcinoma of the anal canal at the MD Anderson Cancer Center from June 2005 to August 2013 were reviewed. The patients were tested for the presence of HPV DNA by in situ hybridization and/or the p16 oncoprotein by immunohistochemistry. Associations between the presence of HPV and clinicopathologic attributes were measured. Of the 72 patients reviewed, 68 tumors (94%) had detectable HPV. Patients with HPV-negative tumors were more likely to be of nonwhite ethnicity (odds ratio, 8.7) and have a strong (>30 pack-year) tobacco history (odds ratio, 8.7). A trend toward improved survival from the time of diagnosis of metastatic disease was noted among patients with HPV-positive tumors. Most patients with metastatic anal cancer had detectable HPV, with differences in tobacco history and ethnicity detected according to HPV status. The high frequency of HPV positivity for patients with metastatic anal cancer has important implications for novel immunotherapy treatment approaches, including ongoing clinical trials with immune checkpoint blockade agents using antibodies targeting the programmed death-1 receptor. Previous studies investigating the clinical features of patients with anal cancer focused on those with early-stage disease. The present study characterizes, for the first time, clinical and pathological features according to human papillomavirus (HPV) status for patients with metastatic anal cancer. A high frequency of HPV-positive tumors and correlations between HPV status and both ethnicity and tobacco history was found. No standard-of-care therapy is available for patients with metastatic anal cancer, and most receive cytotoxic chemotherapy. The high prevalence of HPV in the current population generates optimism for ongoing clinical trials investigating the role of immune checkpoint blockade agents as a novel treatment approach for this disease.

Personalized approaches to active immunotherapy in cancer

Immunotherapy is emerging as a promising anti-cancer curative modality. However, in contrast to recent advances obtained employing checkpoint blockade agents and T cell therapies, clinical efficacy of therapeutic cancer vaccines is still limited. Most vaccination attempts in the clinic represent “off-the shelf” approaches since they target common “self” tumor antigens, shared among different patients. In contrast, personalized approaches of vaccination are tailor-made for each patient and in spite being laborious, hold great potential. Recent technical advancement enabled the first steps in the clinic of personalized vaccines that target patient-specific mutated neo-antigens. Such vaccines could induce enhanced tumor-specific immune response since neo-antigens are mutation-derived antigens that can be recognized by high affinity T cells, not limited by central tolerance. Alternatively, the use of personalized vaccines based on whole autologous tumor cells, overcome the need for the identification of specific tumor antigens. Whole autologous tumor cells could be administered alone, pulsed on dendritic cells as lysate, DNA, RNA or delivered to dendritic cells in-vivo through encapsulation in nanoparticle vehicles. Such vaccines may provide a source for the full repertoire of the patient-specific tumor antigens, including its private neo-antigens. Furthermore, combining next-generation personalized vaccination with other immunotherapy modalities might be the key for achieving significant therapeutic outcome.

Abstract 3364: Epithelial-mesenchymal transition is associated with a profound inflammatory tumor microenvironment in lung adenocarcinoma

Abstract Promising results in the treatment of non-small cell lung cancer (NSCLC) have been seen with immunomodulatory agents targeting immune checkpoints, such as programmed cell death 1 (PD-1) or programmed cell death 1 ligand (PD-L1). However, only a select group of patients respond to these interventions. The identification of biomarkers that predict clinical benefit to immune-based approaches, such as immune checkpoint blockade, is critical to successful translation of these agents. By using integrated gene array analysis in three large independent NSCLC patient datasets along with immunohistochemistry study (IHC), reverse phase protein array (RPPA) and in vivo animal study, we demonstrated that epithelial-mesenchymal transition (EMT) is highly associated with a profound inflammatory tumor microenvironment in lung adenocarcinoma. Our data revealed immune activation and simultaneous development of multiple immune suppressive mechanisms, including elevation of immune checkpoints such as PD-L1, PD-L2, PD-1, TIM-3, BTLA and CTLA-4, as well as an increase in tumor infiltrating CD4+Foxp3+ regulatory T cells, IL-6 and indoleamine 2,3-dioxygenase (IDO) in lung adenocarcinomas with a mesenchymal phenotype. Our data suggested that EMT might represent a potential biomarker to select the patients who will benefit from immune checkpoint blockade agents and other immunotherapies in NSCLC and possibly other cancers. Note: This abstract was not presented at the meeting. Citation Format: Yanyan Lou, Lixia Diao, Parra Cuentas Edwin Roger, Warren L. Denning, Limo Chen, Youhong Fan, Jaime Rodriguez, Lauren Byers, Jing Wang, Vassiliki Papadimitrakopoulou, Behrens Carmen, Ignacio I. Wistuba, Patrick Hwu, John V. Heymach, Don L. Gibbons. Epithelial-mesenchymal transition is associated with a profound inflammatory tumor microenvironment in lung adenocarcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3364. doi:10.1158/1538-7445.AM2015-3364

Safety and efficacy of ipilimumab to treat advanced melanoma in the setting of liver transplantation.

Ipilimumab is a first-in-class immunological checkpoint blockade agent and monoclonal antibody against Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) that has demonstrated survival benefit and durable responses in patients with metastatic melanoma. To date, solid organ transplant recipients have been excluded from clinical trials with cancer immunotherapies on the basis of their concurrent treatment with immunosuppressive agents. We present the first case to our knowledge of a patient with advanced cutaneous melanoma receiving ipilimumab status post orthotopic liver transplantation with a partial response. Transaminitis was observed 4 months after administration of ipilimumab that resolved with close observation. No evidence of graft rejection has been observed to date. This case advocates for further investigation of the safety and efficacy of cancer immunotherapies in solid organ transplant recipients.

Role and complexity of next-generation sequencing in melanoma.

Role and complexity of next-generation sequencing in melanoma.

Immune-Checkpoint Blockade and Active Immunotherapy for Glioma

Cancer immunotherapy has made tremendous progress, including promising results in patients with malignant gliomas. Nonetheless, the immunological microenvironment of the brain and tumors arising therein is still believed to be suboptimal for sufficient antitumor immune responses for a variety of reasons, including the operation of “immune-checkpoint” mechanisms. While these mechanisms prevent autoimmunity in physiological conditions, malignant tumors, including brain tumors, actively employ these mechanisms to evade from immunological attacks. Development of agents designed to unblock these checkpoint steps is currently one of the most active areas of cancer research. In this review, we summarize recent progresses in the field of brain tumor immunology with particular foci in the area of immune-checkpoint mechanisms and development of active immunotherapy strategies. In the last decade, a number of specific monoclonal antibodies designed to block immune-checkpoint mechanisms have been developed and show efficacy in other cancers, such as melanoma. On the other hand, active immunotherapy approaches, such as vaccines, have shown encouraging outcomes. We believe that development of effective immunotherapy approaches should ultimately integrate those checkpoint-blockade agents to enhance the efficacy of therapeutic approaches. With these agents available, it is going to be quite an exciting time in the field. The eventual success of immunotherapies for brain tumors will be dependent upon not only an in-depth understanding of immunology behind the brain and brain tumors, but also collaboration and teamwork for the development of novel trials that address multiple layers of immunological challenges in gliomas.