Integrative analysis reveals selective 9p24.1 amplification, increased PD-1 ligand expression, and further induction via JAK2 in nodular sclerosing Hodgkin lymphoma and primary mediastinal large B-cell lymphoma. Blood. 2010;116:3268-3277. [PMID: 20628145 DOI: 10.1182/blood-2010-05-282780]

Harnessing the immune system through programmed death-1 blockade in the management of Hodgkin lymphoma

Immunotherapy is a rapidly evolving therapeutic option in the treatment of lymphoma. Neoplastic cells evade immune recognition through the programmed death (PD)-1/PD-ligand immune checkpoint pathway. Several novel agents have been developed to restore the immune system's ability to recognize and destroy cancer cells. Nivolumab and pembrolizumab are two anti-PD-1 antibodies that have demonstrated success in the treatment of refractory Hodgkin lymphoma. Harnessing the immune system's ability to target neoplastic cells, ideally without the use of cytotoxic chemotherapeutic agents, is one way in which these novel agents are changing the therapeutic landscape in the treatment of lymphomas. Here, we review the emerging data regarding checkpoint inhibitors in the management of Hodgkin lymphoma, the unique adverse effects encountered with the use of these agents, and a practical approach to the management of these adverse effects. Additionally, we discuss upcoming trials that will further assess the promising future developments of checkpoint inhibition in the treatment of not only Hodgkin lymphoma but also other B cell lymphomas and myeloma. These agents offer immense promise of a future where many lymphomas can be treated without the toxic effects of chemotherapeutic agents.

Surveilling the Potential for Precision Medicine-driven PD-1/PD-L1-targeted Therapy in HNSCC

Immunotherapy is becoming an accepted treatment modality for many patients with cancer and is now approved for use in platinum-refractory recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). Despite these successes, a minority of patients with HNSCC receiving immunotherapy respond to treatment, and few undergo a complete response. Thus, there is a critical need to identify mechanisms regulating immune checkpoints in HNSCC such that one can predict who will benefit, and so novel combination strategies can be developed for non-responders. Here, we review the immunotherapy and molecular genetics literature to describe what is known about immune checkpoints in common genetic subsets of HNSCC. We highlight several highly recurrent genetic lesions that may serve as biomarkers or targets for combination immunotherapy in HNSCC.

[Immune-checkpoint and hemopathies]

Immune-checkpoint inhibitors represent potent new therapies for most lymphomas, particularly for refractory diseases. Contrasting with solid tumors the majority of lymphoma are sensitive to conventional therapies and immunotherapies such as anti-CD20 or anti-CD30. But relapsing lymphoma or refractory disease have a very poor prognosis and new drugs are mandatory. Immune-checkpoint inhibitors targeting CTLA4, PD-1 et PD-L1 demonstrated efficiency with prolonged survivals even after bone marrow allograft for aggressive disease. Lymphomas differ from solid tumors as tumor cells belong to the immune compartment and therefore molecules targeting immune cells may act on both immune environment and tumor cells. Furthermore, PD-L1 expression in most lymphomas is related to tumor cell molecular alterations such as PD-L1 gene amplification or mutation. PD-L1 protein expression on tumor cells and immune cells, particularly it frequency and distribution vary according to different lymphoma subtype and it may help to assess diagnosis as it may predict therapeutical response.

Emerging role of checkpoint blockade therapy in lymphoma

Following the successful application of immune checkpoint blockade therapy (CBT) in refractory solid tumors, it has recently gained momentum as a promising modality in the treatment of relapsed lymphoma. This significant therapeutic advance stems from decades of research that elucidated the role of immune regulation pathways and the mechanisms by which tumors can engage these critical pathways to escape immune detection. To date, two main pathways, the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1), have emerged as key targets of CBT demonstrating unprecedented activity particularly in heavily pretreated relapsed/refractory Hodgkin lymphoma and some forms of non-Hodgkin disease. Herein we provide a brief discussion of checkpoint blockade in the context of lymphoma biology with a specific focus on novel checkpoint inhibitors and their therapeutic activity. We discuss current clinical trials and the landscape of CBT to underscore both the remarkable progress and foreseeable limitations of this novel treatment strategy. In particular, we build upon state-of-the-art knowledge and clinical insights gained from the early trials to review potential approaches to how CBT may be integrated with other treatment modalities, including chemoimmunotherapy to improve patient outcomes in the future. Finally, as the role of CBT evolves to potentially become a cornerstone of therapy in refractory/relapsed lymphoma, we briefly emphasize the importance of predictive biomarkers in an effort to select appropriate patients who are most likely to derive benefit from CBT.

Broad and Conserved Immune Regulation by Genetically Heterogeneous Melanoma Cells

Although mutations drive cancer, it is less clear to what extent genetic defects control immune mechanisms and confer resistance to T-cell-based immunotherapy. Here, we studied the reactions of malignant and benign melanocyte lines to cytotoxic CD8⁺ T cells (CTL) using flow cytometry and gene expression analyses. We found rapid and broad upregulation of immune-regulatory genes, essentially triggered by CTL-derived IFNγ and augmented by TNFα. These reactions were predominantly homogenous, independent of oncogenic driver mutations, and similar in benign and malignant cells. The reactions exhibited both pro- and antitumorigenic potential and primarily corresponded to mechanisms that were conserved, rather than acquired, by mutations. Similar results were obtained from direct ex vivo analysis of the tumor microenvironment. Thus, immune regulation in the tumor landscape may often be driven by conserved mechanisms, which may explain why T-cell-based immunotherapy can provide durable benefits with relatively infrequent escape. Cancer Res; 77(7); 1623-36. ©2017 AACR.

Temporally Distinct PD-L1 Expression by Tumor and Host Cells Contributes to Immune Escape

Antibody blockade of programmed death-1 (PD-1) or its ligand, PD-L1, has led to unprecedented therapeutic responses in certain tumor-bearing individuals, but PD-L1 expression's prognostic value in stratifying cancer patients for such treatment remains unclear. Reports conflict on the significance of correlations between PD-L1 on tumor cells and positive clinical outcomes to PD-1/PD-L1 blockade. We investigated this issue using genomically related, clonal subsets from the same methylcholanthrene-induced sarcoma: a highly immunogenic subset that is spontaneously eliminated in vivo by adaptive immunity and a less immunogenic subset that forms tumors in immunocompetent mice, but is sensitive to PD-1/PD-L1 blockade therapy. Using CRISPR/Cas9-induced loss-of-function approaches and overexpression gain-of-function techniques, we confirmed that PD-L1 on tumor cells is key to promoting tumor escape. In addition, the capacity of PD-L1 to suppress antitumor responses was inversely proportional to tumor cell antigenicity. PD-L1 expression on host cells, particularly tumor-associated macrophages (TAM), was also important for tumor immune escape. We demonstrated that induction of PD-L1 on tumor cells was IFNγ-dependent and transient, but PD-L1 induction on TAMs was of greater magnitude, only partially IFNγ dependent, and was stable over time. Thus, PD-L1 expression on either tumor cells or host immune cells could lead to tumor escape from immune control, indicating that total PD-L1 expression in the immediate tumor microenvironment may represent a more accurate biomarker for predicting response to PD-1/PD-L1 blockade therapy, compared with monitoring PD-L1 expression on tumor cells alone. Cancer Immunol Res; 5(2); 106-17. ©2017 AACR.

Utilisation des inhibiteurs de PD-1 dans les hémopathies lymphoïdes

ANTI-PD-1 ANTIBODIES THERAPEUTIC USE IN LYMPHOID NEOPLASMS: Immune checkpoints blockade is under investigation in oncology, and has demonstrated its clinical efficacy. In hematology, immune checkpoints blockade is in earlier stages of development, but there are strong evidences of PD-1 blockade anti-tumor efficacy in some lymphoid malignancies. In this review, we will discuss the main clinical results of PD-1 inhibitors in lymphoid neoplasms and the main perspectives of development.

Diffuse Large B-Cell Lymphoma in the Era of Precision Oncology: How Imaging Is Helpful

Diffuse large B cell lymphoma (DLBCL) is the most common histological subtype of Non-Hodgkin's lymphoma. As treatments continues to evolve, so do imaging strategies, and positron emission tomography (PET) has emerged as the most important imaging tool to guide oncologists in the diagnosis, staging, response assessment, relapse/recurrence detection,and therapeutic decision making of DLBCL. Other imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and conventional radiography are also used in the evaluation of lymphoma. MRI is useful for nervous system and musculoskeletal system involvement and is emerging as a radiation free alternative to PET/CT. This article provides a comprehensive review of both the functional and morphological imaging modalities, available in the management of DLBCL.

Oncogenic Signaling Pathways and Pathway-Based Therapeutic Biomarkers in Lymphoid Malignancies

Lymphoma is characterized by heterogeneous biology, pathologic features, and clinical outcome. This has been proven by accumulating pathologic and molecular evidence attributed to underlying aberrant alterations at genetic, epigenetic, transcriptional, protein, microenvironmental levels, and dysregulated oncogenic signaling pathways. In the era of precision medicine, targeting oncogenic pathways to design drugs and to optimize treatment regimens for the lymphoma patients is feasible and clinically significant. As such, further understanding of the biology and the mechanisms behind lymphoma development and identification of oncogenic pathway activation and pathway-based biomarkers to better design precise therapies are challenging but hopeful. Furthermore, pathway-based targeted therapies in combination with traditional chemotherapy, single specific targeted antibody therapy, and immunotherapy might raise the hope for the patients with lymphoma, especially for relapsed and refractory lymphoma patients.

The emerging role of immune checkpoint inhibition in malignant lymphoma

To evade elimination by the host immune system, tumor cells commonly exploit physiological immune checkpoint pathways, restraining efficient anti-tumor immune cell function. Growing understanding of the complex dialog between tumor cells and their microenvironment contributed to the development of immune checkpoint inhibitors. This innovative strategy has demonstrated paradigm-shifting clinical activity in various malignancies. Antibodies targeting programmed death 1 and cytotoxic T-lymphocyte-associated protein-4 are also being investigated in lymphoid malignancies with varying levels of activity and a favorable toxicity profile. To date, evaluated only in the setting of relapsed or refractory disease, anti-programmed death 1 antibodies such as nivolumab and pembrolizumab show encouraging response rates particularly in classical Hodgkin lymphoma but also in follicular lymphoma and diffuse-large B-cell lymphoma. As the first immune checkpoint inhibitor in lymphoma, nivolumab was approved for the treatment of relapsed or refractory classical Hodgkin lymphoma by the Food and Drug Administration in May 2016. In this review, we assess the role of the pathways involved and potential rationale of checkpoint inhibition in various lymphoid malignancies. In addition to data from current clinical trials, immune-related side effects, potential limitations and future perspectives including promising combinatory approaches with immune checkpoint inhibition are discussed.

Hodgkin Lymphoma: Current Status and Clinical Trial Recommendations

The National Clinical Trials Network lymphoid malignancies Clinical Trials Planning Meeting (CTPM) occurred in November of 2014. The scope of the CTPM was to prioritize across the lymphoid tumors clinically significant questions and to foster strategies leading to biologically informed and potentially practice changing clinical trials. This review from the Hodgkin lymphoma (HL) subcommittee of the CTPM discusses the ongoing clinical challenges in HL, outlines the current standard of care for HL patients from early to advanced stage, and surveys the current science with respect to biomarkers and the landscape of ongoing clinical trials. Finally, we suggest areas of unmet need in HL and elucidate promising therapeutic strategies to guide future HL clinical trials planning across the NCTN.

Triple-negative breast cancers with amplification of JAK2 at the 9p24 locus demonstrate JAK2-specific dependence

Amplifications at 9p24 have been identified in breast cancer and other malignancies, but the genes within this locus causally associated with oncogenicity or tumor progression remain unclear. Targeted next-generation sequencing of postchemotherapy triple-negative breast cancers (TNBCs) identified a group of 9p24-amplified tumors, which contained focal amplification of the Janus kinase 2 (JAK2) gene. These patients had markedly inferior recurrence-free and overall survival compared to patients with TNBC without JAK2 amplification. Detection of JAK2/9p24 amplifications was more common in chemotherapy-treated TNBCs than in untreated TNBCs or basal-like cancers, or in other breast cancer subtypes. Similar rates of JAK2 amplification were confirmed in patient-derived TNBC xenografts. In patients for whom longitudinal specimens were available, JAK2 amplification was selected for during neoadjuvant chemotherapy and eventual metastatic spread, suggesting a role in tumorigenicity and chemoresistance, phenotypes often attributed to a cancer stem cell-like cell population. In TNBC cell lines with JAK2 copy gains or amplification, specific inhibition of JAK2 signaling reduced mammosphere formation and cooperated with chemotherapy in reducing tumor growth in vivo. In these cells, inhibition of JAK1-signal transducer and activator of transcription 3 (STAT3) signaling had little effect or, in some cases, counteracted JAK2-specific inhibition. Collectively, these results suggest that JAK2-specific inhibitors are more efficacious than dual JAK1/2 inhibitors against JAK2-amplified TNBCs. Furthermore, JAK2 amplification is a potential biomarker for JAK2 dependence, which, in turn, can be used to select patients for clinical trials with JAK2 inhibitors.

Mature aggressive B-cell lymphoma across age groups - molecular advances and therapeutic implications

INTRODUCTION

Mature B-cell lymphoma represents the most common type of Non-Hodgkin lymphoma, and different subtypes prevail at different patient ages. Areas covered: We review recent data on differences and commonalities in mature B-cell lymphoma occurring in adult and pediatric patients, with a special emphasis on molecular advances and therapeutic implications. To this end, we will discuss knowledge on diffuse large B-cell lymphoma and Burkitt lymphoma/leukemia, which are the most frequent subtypes in adult and pediatric patients, respectively, and on primary mediastinal B-cell lymphoma, which is a subtype of mature B-cell lymphoma occurring mainly in adolescents and young adults with a female predominance. Expert commentary: Molecular profiling has revealed molecular alterations that can be used to further classify the subtypes of mature B-cell lymphoma. These new subgroups frequently respond differentially to targeted therapeutic strategies. Future clinical trials utilizing new drugs will address this issue by combining clinical data and response assessment with a molecular workup of the corresponding lymphomas.

The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of hematologic malignancies: multiple myeloma, lymphoma, and acute leukemia

Increasing knowledge concerning the biology of hematologic malignancies as well as the role of the immune system in the control of these diseases has led to the development and approval of immunotherapies that are resulting in impressive clinical responses. Therefore, the Society for Immunotherapy of Cancer (SITC) convened a hematologic malignancy Cancer Immunotherapy Guidelines panel consisting of physicians, nurses, patient advocates, and patients to develop consensus recommendations for the clinical application of immunotherapy for patients with multiple myeloma, lymphoma, and acute leukemia. These recommendations were developed following the previously established process based on the Institute of Medicine's clinical practice guidelines. In doing so, a systematic literature search was performed for high-impact studies from 2004 to 2014 and was supplemented with further literature as identified by the panel. The consensus panel met in December of 2014 with the goal to generate consensus recommendations for the clinical use of immunotherapy in patients with hematologic malignancies. During this meeting, consensus panel voting along with discussion were used to rate and review the strength of the supporting evidence from the literature search. These consensus recommendations focus on issues related to patient selection, toxicity management, clinical endpoints, and the sequencing or combination of therapies. Overall, immunotherapy is rapidly emerging as an effective therapeutic strategy for the management of hematologic malignances. Evidence-based consensus recommendations for its clinical application are provided and will be updated as the field evolves.

Challenges and opportunities for checkpoint blockade in T-cell lymphoproliferative disorders

The T-cell lymphoproliferative disorders are a heterogeneous group of non-Hodgkin’s lymphomas (NHL) for which current therapeutic strategies are inadequate, as most patients afflicted with these NHL will succumb to disease progression within 2 years of diagnosis. Appreciation of the genetic and immunologic landscape of these aggressive NHL, including PD-L1 (B7-H1, CD274) expression by malignant T cells and within the tumor microenvironment, provides a strong rationale for therapeutic targeting this immune checkpoint. While further studies are needed, the available data suggests that responses with PD-1 checkpoint blockade alone will unlikely approach those achieved in other lymphoproliferative disorders. Herein, we review the unique challenges posed by the T-cell lymphoproliferative disorders and discuss potential strategies to optimize checkpoint blockade in these T-cell derived malignancies.

PD1 and PDL1 expression in primary central nervous system diffuse large B-cell lymphoma are frequent and expression of PD1 predicts poor survival

Primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) is a rare and aggressive type of diffuse large B-cell lymphoma (DLBCL) whit poorly understood pathogenesis. Finding biomarkers associated with patient survival may be important for understanding its physiopathology and to develop new therapeutic approaches. We investigated 32 PCNS-DLBCL from immunocompetent patients for BCL2, CMYC, LMO2, and P53 expression and for cytogenetic aberrations of BCL2, BCL6, and MYC genes, all known for their prognostic value in systemic DLBCL (s-DLBCL). We analyzed PD1 and PDL1 protein expression in both tumor infiltrating lymphocytes (TILs) and tumor cells. Finally, we searched for correlation between biological data and clinical course. The PCNS-DLBCL expressed BCL2, CMYC, LMO2, and P53 at similar frequency than s-DLBCL but without significant prognostic on survival. None cases harbored aberrations involving BCL2 and MYC gene whereas BCL6 abnormalities were present in 20.7% of cases but without value on survival. Expression of PD1 in TILs and PDL1 in tumor cells was observed at higher rates than in s-DLBCL (58% and 37%, respectively). The PD1 expression in TILs correlated with PDL1 expression in tumor cells (P = .001). Presence of PD1 positive TILs was associated with poorer overall survival (P = .011). Patients with PDL1 overexpression tended to better response to chemotherapy (P = .23). In conclusion PCNS-DLBCL pathogenesis differs from s-DLBCL without prognostic value of the phenotypic and cytogenetic parameters known for their pejorative impact in the latter. The PD1/PDL1 pathway plays a strong role in PCNS-DLBCL and represents an attractive target for this aggressive lymphoma.

The PD1:PD-L1/2 Pathway from Discovery to Clinical Implementation

The immune system maintains a critically organized network to defend against foreign particles, while evading self-reactivity simultaneously. T lymphocytes function as effectors and play an important regulatory role to orchestrate the immune signals. Although central tolerance mechanism results in the removal of the most of the autoreactive T cells during thymic selection, a fraction of self-reactive lymphocytes escapes to the periphery and pose a threat to cause autoimmunity. The immune system evolved various mechanisms to constrain such autoreactive T cells and maintain peripheral tolerance, including T cell anergy, deletion, and suppression by regulatory T cells (TRegs). These effects are regulated by a complex network of stimulatory and inhibitory receptors expressed on T cells and their ligands, which deliver cell-to-cell signals that dictate the outcome of T cell encountering with cognate antigens. Among the inhibitory immune mediators, the pathway consisting of the programed cell death 1 (PD-1) receptor (CD279) and its ligands PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273) plays an important role in the induction and maintenance of peripheral tolerance and for the maintenance of the stability and the integrity of T cells. However, the PD-1:PD-L1/L2 pathway also mediates potent inhibitory signals to hinder the proliferation and function of T effector cells and have inimical effects on antiviral and antitumor immunity. Therapeutic targeting of this pathway has resulted in successful enhancement of T cell immunity against viral pathogens and tumors. Here, we will provide a brief overview on the properties of the components of the PD-1 pathway, the signaling events regulated by PD-1 engagement, and their consequences on the function of T effector cells.

What have we learned from immunotherapy? Report from the 3rd and 4th meetings of the Campania Society of Oncology Immunotherapy (SCITO)

Treatment strategies that target the immune system provide the opportunity for antitumor activity across multiple cancer types, regardless of mutational status or tumor histology. While many of the initial advances in immunotherapy have been in melanoma, the focus has now broadened to include many other solid as well as hematological cancers. Different immunotherapeutic approaches are being evaluated across tumor types and their various novel mechanisms of action and safety profiles offer the potential for a variety of combination regimens. Ongoing and planned investigation of these immunotherapies, alone and in combination, represents the start of a new chapter in our treatment of cancer and offers the hope of better outcomes for patients with a wide range of cancers. Recent advances in the use of immune-based approaches to treat non-small-cell lung cancer, breast cancer, ovarian cancer, gastrointestinal cancer, hepatocellular carcinoma, head and neck cancer and lymphoma were discussed at the 2015 Spring and Winter meetings of the Campania Society of Oncology Immunotherapy (SCITO) and are reported here.

Histological Transformation and Progression in Follicular Lymphoma: A Clonal Evolution Study

BACKGROUND

Follicular lymphoma (FL) is an indolent, yet incurable B cell malignancy. A subset of patients experience an increased mortality rate driven by two distinct clinical end points: histological transformation and early progression after immunochemotherapy. The nature of tumor clonal dynamics leading to these clinical end points is poorly understood, and previously determined genetic alterations do not explain the majority of transformed cases or accurately predict early progressive disease. We contend that detailed knowledge of the expansion patterns of specific cell populations plus their associated mutations would provide insight into therapeutic strategies and disease biology over the time course of FL clinical histories.

METHODS AND FINDINGS

Using a combination of whole genome sequencing, targeted deep sequencing, and digital droplet PCR on matched diagnostic and relapse specimens, we deciphered the constituent clonal populations in 15 transformation cases and 6 progression cases, and measured the change in clonal population abundance over time. We observed widely divergent patterns of clonal dynamics in transformed cases relative to progressed cases. Transformation specimens were generally composed of clones that were rare or absent in diagnostic specimens, consistent with dramatic clonal expansions that came to dominate the transformation specimens. This pattern was independent of time to transformation and treatment modality. By contrast, early progression specimens were composed of clones that were already present in the diagnostic specimens and exhibited only moderate clonal dynamics, even in the presence of immunochemotherapy. Analysis of somatic mutations impacting 94 genes was undertaken in an extension cohort consisting of 395 samples from 277 patients in order to decipher disrupted biology in the two clinical end points. We found 12 genes that were more commonly mutated in transformed samples than in the preceding FL tumors, including TP53, B2M, CCND3, GNA13, S1PR2, and P2RY8. Moreover, ten genes were more commonly mutated in diagnostic specimens of patients with early progression, including TP53, BTG1, MKI67, and XBP1.

CONCLUSIONS

Our results illuminate contrasting modes of evolution shaping the clinical histories of transformation and progression. They have implications for interpretation of evolutionary dynamics in the context of treatment-induced selective pressures, and indicate that transformation and progression will require different clinical management strategies.

Genomic Approaches to Understanding Response and Resistance to Immunotherapy

Immunotherapy has led to a paradigm shift in the treatment of some malignancies, providing long-term, durable responses for patients with advanced cancers. However, such therapy has benefited only a subset of patients, with some patients failing to respond to treatment at all and others achieving a limited response followed by tumor progression. Understanding factors contributing to an effective response and further elucidating mechanisms of resistance will be crucial as these therapies are applied more broadly. Genomics-based approaches have significantly advanced the study of response and resistance to immunotherapy in general, and to immune checkpoint blockade more specifically. Here, we review how genomic and transcriptomic approaches have identified both somatic and germline positive correlates of response, including high mutational/neoantigen load and low intratumoral heterogeneity, among others. The genomic analysis of resistant tumors has additionally identified crucial factors involved in resistance to immune checkpoint blockade, including loss of PTEN and upregulation of other immune checkpoints. Overall, the continued use of genomic techniques at the point of care, combined with appropriate functional studies, would ideally lead to a better understanding of why certain patients respond to immune-based therapies, allowing clinicians to identify the subset of patients likely to benefit from such therapy, and potentially providing insight into how other therapies may be added in combination to increase the number of patients who may benefit from immunotherapy. Clin Cancer Res; 22(23); 5642-50. ©2016 AACR.

What does PD-L1 positive or negative mean?

Ribas and Hu-Lieskovan show that different processes may lead to the expression of PD-L1 on cancer cells, and each one of them may have a different meaning to interpret the results of clinical trials with anti–PD-1/L1 antibodies.

Expression of the programmed death-1 (PD-1) ligand 1 (PD-L1) is used to select patients and analyze responses to anti–PD-1/L1 antibodies. The expression of PD-L1 is regulated in different ways, which leads to a different significance of its presence or absence. PD-L1 positivity may be a result of genetic events leading to constitutive PD-L1 expression on cancer cells or inducible PD-L1 expression on cancer cells and noncancer cells in response to a T cell infiltrate. A tumor may be PD-L1 negative because it has no T cell infiltrate, which may be reversed with an immune response. Finally, a tumor that is unable to express PD-L1 because of a genetic event will always be negative for PD-L1 on cancer cells.

Understanding the epigenetic regulation of tumours and their microenvironments: opportunities and problems for epigenetic therapy

The tumour microenvironment plays an instrumental role in cancer development, progression and treatment response/resistance. Accumulating evidence is underscoring the fundamental importance of epigenetic regulation in tumour immune evasion. Following many pioneering discoveries demonstrating malignant transformation through epigenetic anomalies ('epimutations'), there is also a growing emphasis on elucidating aberrant epigenetic mechanisms that reprogramme the milieu of tumour-associated immune and stromal cells towards an immunosuppressive state. Pharmacological inhibition of DNA methylation and histone modifications can augment the efficiency of immune checkpoint blockage, and unleash anti-tumour T-cell responses. However, these non-specific agents also represent a 'double-edged sword', as they can also reactivate gene transcription of checkpoint molecules, interrupting immune surveillance programmes. By understanding the impact of epigenetic control on the tumour microenvironment, rational combinatorial epigenetic and checkpoint blockage therapies have the potential to harness the immune system for the treatment of cancer. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The role of immune checkpoint inhibition in the treatment of ovarian cancer

The introduction of immune checkpoint inhibitors has revolutionized treatment of multiple cancers and has bolstered interest in this treatment approach. So far, emerging clinical data show limited clinical efficacy of these agents in ovarian cancer with objective response rates of 10–15% with some durable responses. In this review, we present emerging clinical data of completed trials of immune checkpoint inhibitors and review ongoing studies. In addition we examine the current knowledge of the tumor microenvironment of ovarian cancers with a focus on the significance of PD-L1 expression and tumor-infiltrating lymphocytes on predicting response to immune checkpoint blockade. We evaluate approaches to improve treatment outcomes through the use of predictive biomarkers and patient selection. Finally, we review management considerations including immune related adverse events and response criteria.

Nivolumab in the Treatment of Hodgkin Lymphoma

Despite an extensive immune infiltrate that is recruited to the tumor by malignant Reed-Sternberg cells in Hodgkin lymphoma, the antitumor immune response is ineffective and unable to eradicate the malignant cells. The ineffective immune response is in part due to PD-1 signaling that renders intratumoral immune cells anergic. Reed-Sternberg cells have been shown to upregulate expression of the PD-1 ligands, PD-L1 and PD-L2, due to either genetic alterations at chromosome 9p24.1 or Epstein-Barr virus infection, and these ligands suppress the function of PD-1⁺ intratumoral T cells. Blockade of PD-1 signaling has proven to be a highly successful therapeutic approach, and the use of the anti-PD-1 mAb nivolumab recently received accelerated approval by the FDA for patients with classical Hodgkin lymphoma that has relapsed or progressed after autologous stem cell transplant and posttransplantation brentuximab vedotin. Initial clinical trials using nivolumab in this patient population resulted in high response rates that were durable. Adverse events associated with nivolumab included immune-mediated adverse reactions and infusion reactions, but these were well tolerated, allowing for continued nivolumab administration. Clinical trials are now in progress to test the use of nivolumab in combination with standard chemotherapy or with novel agents with a goal of improving the outcome of patients with Hodgkin lymphoma. Clin Cancer Res; 23(7); 1623-6. ©2016 AACR.

PD-L1 Status in Refractory Lymphomas

Targeted immunotherapy based on PD-1/PD-L1 suppression has revolutionized the treatment of various solid tumors. A remarkable improvement has also been observed in the treatment of patients with refractory/relapsing classical Hodgkin lymphoma (cHL). We investigated PD-L1 status in a variety of treatment resistant lymphomas. Tumor samples from 78 patients with therapy resistant lymphomas were immunohistochemically (IHC) investigated for the expression of PD-L1 using two antibody clones (SP142 and SP263, Ventana). Thirteen PD-L1+ cases were further analyzed for gene copy number variations (CNV) by NGS and for PD-L1/JAK2/PD-L2 co-amplification using fluorescent in-situ hybridization assay (FISH). PD-L1 positivity (≥5% positive cancer cells, IHC) was present in 32/77 (42%) and 33/71 cases (46%) using SP142 and SP263 antibodies, respectively. Concordance between the two anti-PD-L1 clones was high with only three (4%) discrepant cases. The strongest and consistent (10/11 cases) expression was observed in cHL and primary mediastinal B-cell lymphomas (3/3). Diffuse large B-cell lymphomas (DLBCL) were frequently positive (13/26) irrespective of subtype. Follicular (1/8), peripheral T-cell (3/11) and mantle cell (1/8) lymphomas were rarely positive, while small lymphocytic lymphoma/CLL and marginal zone lymphomas were consistently negative (3/3). Co-amplification/CNVs of PD-L1/JAK2/PD-L2 were observed in 3 cases of DLBCL and cHL, respectively. Of note, all three cHL-amplified cases were positive by FISH, but not by NGS. Since only a fraction of the IHC positive lymphoma cases were positive by FISH and NGS assays, other mechanisms are involved in PD-L1 upregulation, especially in DLBCL. FISH assay may be more suitable than NGS assay for determination of PD-L1 alterations in cHL.

Association of PD-1/PD-L axis expression with cytolytic activity, mutational load, and prognosis in melanoma and other solid tumors

Programmed cell death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) checkpoint blockade has led to remarkable and durable objective responses in a number of different tumor types. A better understanding of factors associated with the PD-1/PD-L axis expression is desirable, as it informs their potential role as prognostic and predictive biomarkers and may suggest rational treatment combinations. In the current study, we analyzed PD-L1, PD-L2, PD-1, and cytolytic activity (CYT) expression, as well as mutational density from melanoma and eight other solid tumor types using The Cancer Genome Atlas database. We found that in some tumor types, PD-L2 expression is more closely linked to Th1/IFNG expression and PD-1 and CD8 signaling than PD-L1 In contrast, mutational load was not correlated with a Th1/IFNG gene signature in any tumor type. PD-L1, PD-L2, PD-1, CYT expression, and mutational density are all positive prognostic features in melanoma, and conditional inference modeling revealed PD-1/CYT expression (i.e., an inflamed tumor microenvironment) as the most impactful feature, followed by mutational density. This study elucidates the highly interdependent nature of these parameters, and also indicates that future biomarkers for anti-PD-1/PD-L1 will benefit from tumor-type-specific, integrated, mRNA, protein, and genomic approaches.

Checkpoint Inhibition: Programmed Cell Death 1 and Programmed Cell Death 1 Ligand Inhibitors in Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a lymphoid malignancy characterized by a reactive immune infiltrate surrounding relatively few malignant cells. In this scenario, active immune evasion seems to play a central role in allowing tumor progression. Immune checkpoint inhibitor pathways are normal mechanisms of T-cell regulation that suppress immune effector function following an antigenic challenge. Hodgkin lymphoma cells are able to escape immune surveillance by co-opting these mechanisms. The programmed cell death 1 (PD-1) pathway in particular is exploited in HL as the malignant Hodgkin and Reed-Sternberg cells express on their surface cognate ligands (PD-L1/L2) for the PD-1 receptor and thereby dampen the T-cell-mediated antitumoral response. Monoclonal antibodies that interact with and disrupt the PD-1:PD-L1/L2 axis have now been developed and tested in early-phase clinical trials in patients with advanced HL with encouraging results. The remarkable clinical activity of PD-1 inhibitors in HL highlights the importance of immune checkpoint pathways as therapeutic targets in HL. In this review, we discuss the rationale for targeting PD-1 and PD-L1 in the treatment of HL. We will evaluate the published clinical data on the different agents and highlight the safety profile of this class of agents. We discuss the available evidence on the use of biomarkers as predictors of response to checkpoint blockade and summarize the areas under active investigation in the use of PD-1/PD-L1 inhibitors for the treatment of HL.

PD-1-PD-L1 immune-checkpoint blockade in B-cell lymphomas

Cancer cells can escape T-cell-mediated cellular cytotoxicity by exploiting the inhibitory programmed cell-death protein 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) immune checkpoint. Indeed, therapeutic antibodies that block the PD-1-PD-L1 axis induce durable clinical responses against a growing list of solid tumours. B-cell lymphomas also leverage this checkpoint to escape immune recognition, although the outcomes of PD-1-PD-L1 blockade, and the correlations between PD-L1 expression and treatment responses, are less-well elucidated in these diseases than in solid cancers. Nevertheless, in patients with Hodgkin lymphoma, amplification of the gene encoding PD-L1 is commonly associated with increased expression of this protein on Reed-Sternberg cells. Correspondingly, PD-1 blockade with nivolumab has been demonstrated to result in response rates as high as 87% in unselected patients with relapsed and/or refractory Hodgkin lymphoma, leading to the FDA approval of nivolumab for this indication in May 2016. The PD-1/PD-L1 axis is probably also important for immune evasion of B-cell lymphomas with a viral aetiology, including those associated with human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV). This Review is focused on the role of PD-1-PD-L1 blockade in unleashing host antitumour immune responses against various B-cell lymphomas, and summarizes the clinical studies of this approach performed to date.

Programmed Death-1 Blockade With Pembrolizumab in Patients With Classical Hodgkin Lymphoma After Brentuximab Vedotin Failure

Purpose Classical Hodgkin lymphoma (HL) frequently exhibits genetic alterations leading to overexpression of the programmed death-1 (PD-1) ligands, suggesting a possible vulnerability to PD-1 blockade. The phase Ib study KEYNOTE-013 (NCT01953692) tested the safety and efficacy of the anti-PD-1 antibody pembrolizumab in patients with hematologic malignancies. Based on its genetics, HL was included as an independent cohort. Methods We enrolled patients with relapsed or refractory HL whose disease progressed on or after treatment with brentuximab vedotin. Patients received pembrolizumab, 10 mg/kg every 2 weeks, until disease progression occurred. Response to treatment was assessed at week 12 and every 8 weeks thereafter. Principal end points were safety and complete remission (CR) rate. Results Thirty-one patients were enrolled; 55% had more than four lines of prior therapy, and 71% had relapsed after autologous stem cell transplantation. Five patients (16%) experienced grade 3 drug-related adverse events (AEs); there were no grade 4 AEs or deaths related to treatment. The CR rate was 16% (90% CI, 7% to 31%). In addition, 48% of patients achieved a partial remission, for an overall response rate of 65% (90% CI, 48% to 79%). Most of the responses (70%) lasted longer than 24 weeks (range, 0.14+ to 74+ weeks), with a median follow-up of 17 months. The progression-free survival rate was 69% at 24 weeks and 46% at 52 weeks. Biomarker analyses demonstrated a high prevalence of PD-L1 and PD-L2 expression, treatment-induced expansion of T cells and natural killer cells, and activation of interferon-γ, T-cell receptor, and expanded immune-related signaling pathways. Conclusions Pembrolizumab was associated with a favorable safety profile. Pembrolizumab treatment induced favorable responses in a heavily pretreated patient cohort, justifying further studies.

The promise of Janus kinase inhibitors in the treatment of hematological malignancies

The Janus kinases (JAK) are a family of kinases that play an essential role in cytokine signaling and are implicated in the pathogenesis of autoimmune diseases and hematological malignancies. As a result, the JAKs have become attractive therapeutic targets. The discovery of a JAK2 point mutation (JAK2 V617F) as the main cause of polycythemia vera lead to the development and FDA approval of a JAK1/2 inhibitor, ruxolitinib, in 2011. This review focuses on the various JAK and associated components aberrations implicated in myeloproliferative neoplasms, leukemias, and lymphomas. In addition to ruxolitinib, other JAK inhibitors are currently being evaluated in clinical trials for treating hematological malignancies. The use of JAK inhibitors alone or in combination therapy should be considered as a way to deliver targeted therapy to patients.

Metastatic basal cell carcinoma with amplification of PD-L1: exceptional response to anti-PD1 therapy

Metastatic basal cell carcinomas are rare malignancies harbouring Hedgehog pathway alterations targetable by SMO antagonists (vismodegib/sonidegib). We describe, for the first time, the molecular genetics and response of a patient with Hedgehog inhibitor-resistant metastatic basal cell carcinoma who achieved rapid tumour regression (ongoing near complete remission at 4 months) with nivolumab (anti-PD1 antibody). He had multiple hallmarks of anti-PD1 responsiveness including high mutational burden (>50 mutations per megabase; 19 functional alterations in tissue next-generation sequencing (NGS; 315 genes)) as well as PDL1/PDL2/JAK2 amplification (as determined by both tissue NGS and by analysis of plasma-derived cell-free DNA). The latter was performed using technology originally developed for the genome-wide detection of sub-chromosomal copy-number alterations (CNAs) in noninvasive prenatal testing and showed numerous CNAs including amplification of the 9p24.3-9p22.2 region containing PD-L1, PD-L2 and JAK2. Of interest, PD-L1, PD-L2 and JAK2 amplification is a characteristic of Hodgkin lymphoma, which is exquisitely sensitive to nivolumab. In conclusion, selected SMO antagonist-resistant metastatic basal cell carcinomas may respond to nivolumab based on underlying molecular genetic mechanisms that include PD-L1 amplification and high tumour mutational burden.

Checkpoint Inhibition in Hodgkin Lymphoma: Saving the Best for Last?

Hodgkin lymphoma is a unique disease entity characterized by a low number of neoplastic tumor cells surrounded by an inflammatory microenvironment composed of dysfunctional immune cells. Recent molecular and genetic studies have revealed that upregulation of the immune checkpoint pathway programmed death 1/programmed death ligand 1 is a key oncogenic driver of Hodgkin lymphoma. Corroborating these mechanistic studies, early-phase clinical trials using the checkpoint inhibitors nivolumab and pembrolizumab in treatment regimens for relapsed and/or refractory Hodgkin lymphoma have demonstrated impressive response rates, a promising durability of response, and a favorable side-effect profile. Given its targeted mechanism of action, acceptable safety, and clinically meaningful activity, the checkpoint inhibitor nivolumab was recently approved by the US Food and Drug Administration as therapy for classical Hodgkin lymphoma that has relapsed or progressed after autologous stem cell transplantation (ASCT) and post-ASCT consolidation therapy with brentuximab vedotin. In this article we review the scientific rationale, preclinical evidence, and most recent clinical data for the use of checkpoint inhibitor therapy in patients with relapsed Hodgkin lymphoma.

A case report and literature review of primary resistant Hodgkin lymphoma: a response to anti-PD-1 after failure of autologous stem cell transplantation and brentuximab vedotin

Hodgkin lymphoma (HL) is a highly curable hematologic malignancy, and ~70% of cases can be cured with combination chemotherapy with or without radiation. However, patients with primary resistant disease have a cure rate of <30%. For such patients, high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is considered to be the standard treatment. If patients fail to respond to ASCT or relapse soon thereafter, they usually receive another ASCT, allogeneic stem cell transplantation or treatment with novel agents. This case report presents the case of a 54-year-old patient with primary resistant HL who received single-agent treatment, brentuximab vedotin, after ASCT relapse. Despite treatment with brentuximab vedotin, the disease continued to progress. In patients with such highly resistant disease, the treatment options are limited. Depending on the physical condition and the willingness of the patient, pembrolizumab, a programmed cell death protein-1 inhibitor, can be given as salvage therapy. But, out of our expectation, the patient achieved a very good partial response after four cycles of pembrolizumab. No serious adverse events were observed with pembrolizumab treatment. This case provides support for a new and effective strategy for treating primary resistant Hodgkin lymphoma.

Checkpoint inhibitors and radiation treatment in Hodgkin's lymphoma : New study concepts of the German Hodgkin Study Group

BACKGROUND

Patients with classical Hodgkin's lymphoma (cHL) have a good prognosis even in advanced stages. However, combined chemo- and radiotherapy, as the standard of care, is also associated with treatment-related toxicities such as organ damage, secondary neoplasias, infertility, or fatigue and long-term fatigue. Many patients suffer from this burden although their cHL was cured. Therefore, the efficacy of immune checkpoint inhibitors like anti-PD1/PD-L1 antibodies in the treatment of solid cancers and also in HL offers new options. A remarkable and durable response rate with a favorable toxicity profile was observed in heavily pretreated cHL patients.

METHODS

Planning to perform prospective randomized clinical trials in the content of radio-immune treatment in patients with Hodgkin's lymphoma (HL), we transferred the results of preliminary clinical studies and basic research in clinical relevant study concepts.

RESULTS

Based on these promising early phase trial data, the German Hodgkin Study Group (GHSG) will investigate innovative treatment regimens in upcoming phase II trials.

CONCLUSION

The therapeutic efficacy and potential synergies of anti-PD1 antibodies in combination with chemo- or radiotherapy will be investigated in various settings of HL.

Genomic Approaches to Understanding Response and Resistance to Immunotherapy

Immunotherapy has led to a paradigm shift in the treatment of some malignancies, providing long-term, durable responses for patients with advanced cancers. However, such therapy has benefited only a subset of patients, with some patients failing to respond to treatment at all and others achieving a limited response followed by tumor progression. Understanding factors contributing to an effective response and further elucidating mechanisms of resistance will be crucial as these therapies are applied more broadly. Genomics-based approaches have significantly advanced the study of response and resistance to immunotherapy in general, and to immune checkpoint blockade more specifically. Here, we review how genomic and transcriptomic approaches have identified both somatic and germline positive correlates of response, including high mutational/neoantigen load and low intratumoral heterogeneity, among others. The genomic analysis of resistant tumors has additionally identified crucial factors involved in resistance to immune checkpoint blockade, including loss of PTEN and upregulation of other immune checkpoints. Overall, the continued use of genomic techniques at the point of care, combined with appropriate functional studies, would ideally lead to a better understanding of why certain patients respond to immune-based therapies, allowing clinicians to identify the subset of patients likely to benefit from such therapy, and potentially providing insight into how other therapies may be added in combination to increase the number of patients who may benefit from immunotherapy. Clin Cancer Res; 22(23); 5642-50. ©2016 AACR.

The immunophenotypic spectrum of primary mediastinal large B-cell lymphoma reveals prognostic biomarkers associated with outcome

Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) that shows overlap with classical Hodgkin lymphoma (CHL) and a favorable prognosis compared to mediastinal gray-zone lymphoma (MGZL). We performed immunohistochemistry on initial diagnostic specimens of 49 cases of uniformly treated PMBL to determine the frequency and clinical significance of expression of antigens commonly seen in CHL and MGZL, along with markers previously shown to be prognostic in DLBCL, not otherwise specified. The median age was 37 years with a female:male ratio of 2.3. After a median follow-up of 78 months, 24% of patients had relapsed or refractory disease and 22% had died; the 5-year PFS was 70%. Variable CD15 expression was seen in 31% of cases, but was not associated with adverse outcome. Hans cell-of-origin, proliferation index, and MYC/BCL2 coexpression were not associated with outcome, while low PDL1 (P = 0.011) and high MUM1 (P = 0.065) staining were each associated with shorter PFS. A biologic risk score (one point each for low PDL1 and high MUM1) stratified patients into three prognostic risk groups for PFS (P = 0.001) and OS (P = 0.032). On separate multivariate models, low PDL1 was independent of R-IPI risk group for PFS (HR 6.0, P = 0.023), as was a biologic risk score of 2 (HR 5.6, P = 0.011). Incorporation of the biologic risk score sub-stratified patients within R-IPI groups for both PFS (P < 0.001) and OS (P < 0.001). In summary, we characterize the immunophenotypic spectrum of PMBL and identify PDL1 and MUM1 as prognostic biomarkers for high-risk disease. Am. J. Hematol. 91:E436-E441, 2016. © 2016 Wiley Periodicals, Inc.

Targeting Immune Checkpoints in Hematologic Malignancies

The use of antibodies that target immune checkpoint molecules on the surface of T-lymphocytes and/or tumor cells has revolutionized our approach to cancer therapy. Cytotoxic-T-lymphocyte antigen (CTLA-4) and programmed cell death protein 1 (PD-1) are the two most commonly targeted immune checkpoint molecules. Although the role of antibodies that target CTLA-4 and PD-1 has been established in solid tumor malignancies and Food and Drug Administration approved for melanoma and non-small cell lung cancer, there remains a desperate need to incorporate immune checkpoint inhibition in hematologic malignancies. Unlike solid tumors, a number of considerations must be addressed to appropriately employ immune checkpoint inhibition in hematologic malignancies. For example, hematologic malignancies frequently obliterate the bone marrow and lymph nodes, which are critical immune organs that must be restored for appropriate response to immune checkpoint inhibition. On the other hand, hematologic malignancies are the quintessential immune responsive tumor type, as proven by the success of allogeneic stem cell transplantation (allo-SCT) in hematologic malignancies. Also, sharing an immune cell lineage, malignant hematologic cells often express immune checkpoint molecules that are absent in solid tumor cells, thereby offering direct targets for immune checkpoint inhibition. A number of clinical trials have demonstrated the potential for immune checkpoint inhibition in hematologic malignancies before and after allo-SCT. The ongoing clinical studies and complimentary immune correlatives are providing a growing body of knowledge regarding the role of immune checkpoint inhibition in hematologic malignancies, which will likely become part of the standard of care for hematologic malignancies.

PD-1 blockade in Hodgkin's lymphoma: learning new tricks from an old teacher

INTRODUCTION

Classical Hodgkin's Lymphoma (cHL) is characterized by genetic reliance on the PD-1 pathway. Rapid accumulation of data describing the role and efficacy of PD-1 and its blockade warrants a focused review.

AREAS COVERED

In this article, we will review the unique biologic features that predispose cHL to PD-1 inhibition, current data regarding the safety and efficacy of PD-1 inhibitors in the treatment of cHL, biomarkers of immune response, ongoing clinical trials with PD-1 inhibitors, as well as areas of uncertainty. Expert commentary: The biologic and genetic underpinnings of cHL make it unique among all malignancies in its exquisite sensitivity to PD-1 inhibition. High response rates to single agent PD-1 inhibitors in early phase clinical trials serve as further proof of concept. These data strongly support continued clinical investigation of the evolving role of PD-1 inhibition in classical Hodgkin's lymphoma, including the optimal sequence, setting, and combination to best exploit the immunologic properties of this disease.

Maybe we don't know JAK?

The cornerstone for precision medicine is the development of robust biomarkers that reflect molecular phenotypes and therapeutic vulnerabilities in disease. We recently described Janus kinase-2 (JAK2)-specific inhibition as a therapeutic opportunity in triple negative breast cancers with 9p24 amplification. Here, we comment on this work and discuss the challenges of targeting this amplicon.