CD30 targeting with brentuximab vedotin: a novel therapeutic approach to primary effusion lymphoma

Promising immunotherapeutic approaches for primary effusion lymphoma

Primary effusion lymphoma (PEL) is a large B-cell neoplasm usually presenting as a serious effusion in body cavities without detectable tumor masses. It is an AIDS-related non-Hodgkin's lymphoma (HL) with human herpes virus 8 (HHV8)/Kaposi sarcoma-associated herpes virus (KSHV) infection. A combination antiretroviral therapy (cART) prolongs the lifespan of AIDS and AIDS-related malignant lymphoma patients, but PEL continues to have a dismal prognosis. PEL showed disappointing outcomes with standard chemotherapy such as CHOP or CHOP-like regimens. A PEL status highlights the urgent need for new therapeutic approaches and treatment strategies and improve clinical outcomes. This review discusses the current knowledge and some recent clinical trials for PEL in the platform of immunotherapy as well as promising future immunotherapeutic approaches for PEL.

Monoclonal Antibodies in Oncology: A Decade of Novel Options

Several decades of research and clinical trials have conclusively provided proof of concept on the usefulness of monoclonal antibodies in the armamentarium against cancer. There are numerous mAbs approved for both, the treatment of solid tumors as well as hematological malignancies. These have ranked in the top ten best-selling drugs in recent years and one such mAb, pembrolizumab, is slated to be the highest revenue-generating drug by 2024. A large proportion of the mAbs in oncology have been approved by regulatory agencies in just the past decade and many professionals working in the field have been unable to keep abreast with the latest mAbs available and their mechanism of action. In this review, we aim to provide a systematic compilation of the various mAbs in oncology, approved by the US FDA in the past decade. It also elaborates on the mechanism of action of the newly approved mAbs to provide an overall update of the same. For this purpose, we have referred to the Drugs at FDA and relevant articles from PubMed from the year 2010 to date.

Immunotherapy for KSHV-associated diseases

Kaposi sarcoma herpesvirus (KSHV)-associated diseases (Kaposi sarcoma, multicentric Castleman disease, primary effusion lymphoma, and KSHV inflammatory cytokine syndrome) are associated with immune suppression and dysregulation and loss of KSHV-specific immunity. These diseases are most frequent in people living with HIV as well as those with primary or iatrogenic immune deficiencies. KSHV itself can modulate the immune system via viral homologs of host cytokines or downregulation of immune-surface markers altering host immune surveillance. These factors make KSHV-associated diseases prime targets for immunotherapy approaches. Several agents have been studied or are under investigation in KSHV-associated diseases, including monoclonal antibodies, immunomodulatory agents, and therapeutic cytokines. Here, we review the role of immunotherapies in KSHV-associated diseases.

KSHV/HHV8-mediated hematologic diseases

Kaposi sarcoma (KS) herpesvirus (KSHV), also known as human herpesvirus 8, is the causal agent of KS but is also pathogenetically related to several lymphoproliferative disorders, including primary effusion lymphoma (PEL)/extracavitary (EC) PEL, KSHV-associated multicentric Castleman disease (MCD), KSHV+ diffuse large B-cell lymphoma, and germinotropic lymphoproliferative disorder. These different KSHV-associated diseases may co-occur and may have overlapping features. KSHV, similar to Epstein-Barr virus (EBV), is a lymphotropic gammaherpesvirus that is preferentially present in abnormal lymphoid proliferations occurring in immunecompromised individuals. Notably, both KSHV and EBV can infect and transform the same B cell, which is frequently seen in KSHV+ EBV+ PEL/EC-PEL. The mechanisms by which KSHV leads to lymphoproliferative disorders is thought to be related to the expression of a few transforming viral genes that can affect cellular proliferation and survival. There are critical differences between KSHV-MCD and PEL/EC-PEL, the 2 most common KSHV-associated lymphoid proliferations, including viral associations, patterns of viral gene expression, and cellular differentiation stage reflected by the phenotype and genotype of the infected abnormal B cells. Advances in treatment have improved outcomes, but mortality rates remain high. Our deepening understanding of KSHV biology, clinical features of KSHV-associated diseases, and newer clinical interventions should lead to improved and increasingly targeted therapeutic interventions.

Primary Effusion Lymphoma: A Clinicopathologic Perspective

Primary effusion lymphoma (PEL) is a rare, aggressive B-cell lymphoma that usually localizes to serous body cavities to subsequently form effusions in the absence of a discrete mass. Although some tumors can develop in extracavitary locations, the areas most often affected include the peritoneum, pleural space, and the pericardium. PEL is associated with the presence of human herpesvirus 8 (HHV8), also called the Kaposi sarcoma-associated herpesvirus (KSHV), with some variability in transformation potential suggested by frequent coinfection with the Epstein-Barr virus (EBV) (~80%), although the nature of the oncogenesis is unclear. Most patients suffering with this disease are to some degree immunocompromised (e.g., Human immunodeficiency virus (HIV) infection or post-solid organ transplantation) and, even with aggressive treatment, prognosis remains poor. There is no definitive guideline for the treatment of PEL, although CHOP-like regimens (cyclophosphamide, doxorubicin, vincristine, and prednisone) are frequently prescribed and, given the rarity of this disease, therapeutic focus is being redirected to personalized and targeted approaches in the experimental realm. Current clinical trials include the combination of lenalidomide and rituximab into the EPOCH regimen and the treatment of individuals with relapsed/refractory EBV-associated disease with tabelecleucel.

Efficacy and mechanism of the anti-CD38 monoclonal antibody Daratumumab against primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare, aggressive B cell non-Hodgkin's lymphoma of the body cavities with malignant effusions. The prognosis is poor, and no optimal treatment has been established. CD38 is a type II transmembrane glycoprotein known to overexpress in multiple myeloma (MM). Daratumumab (DARA), a human CD38-targeting monoclonal antibody (mAb), is approved for MM treatment. In this study, we found expression of CD38 on PEL cells and assessed the anti-PEL activity of DARA. We found that both KHYG-1 and N6 (CD16-transfected KHYG-1) NK cell lines showed direct killing activity against PEL cells with induction of CD107a, and NK-mediated cytotoxicity by N6NK (CD16⁺) cells increased with DARA treatment. We confirmed direct NK activity and antibody-dependent cell cytotoxicity (ADCC) by expanded NK cells, indicating that DARA has high ADCC activity. We elucidated the antibody-dependent cell phagocytosis (ADCP) by using human monocyte-derived macrophages (MDMs) and mouse peritoneal macrophages. DARA also showed potent complement-dependent cytolysis (CDC) toward PEL. DARA also induced PEL cell death in the presence of a cross-linking antibody. Moreover, treatment with DARA inhibited tumor growth in a PEL xenograft mouse model. These results provide preclinical evidence that Ab targeting of CD38 could be an effective therapeutic strategy for the treatment of PEL.

Use of Brentuximab Vedotin in a Non-HIV Patient with Primary Effusion Lymphoma

Primary effusion lymphoma is a rare and aggressive large B-cell lymphoma presenting as malignant effusion with poor prognosis. Although it is more prevalent among HIV patients, it has also been described in non-HIV immunocompromised individuals. Given its rarity, there are no large randomized trials regarding the best therapeutic option. The choice of therapy is based on retrospective studies, case reports and preclinical data. We present the case of a non-HIV patient with relapsed disease after treatment with CHOP who was then successfully treated with brentuximab vedotin, achieving complete remission.

LEARNING POINTS

Primary effusion lymphoma is a rare entity in non-HIV patients, so there are no clinical trials regarding therapeutic options or management decisions.Targeted therapy with brentuximab vedotin has been used in other CD30 positive malignancies and in HIV-related primary effusion lymphoma with good outcomes.We present the case of a non-HIV patient with primary effusion lymphoma who was successfully treated with brentuximab vedotin, which highlights the potential role of a new therapeutic approach in this subgroup of patients.

Non-Hodgkin Lymphomas: Malignancies Arising from Mature B Cells

Non-Hodgkin lymphomas (NHLs) are a diverse group of entities, both clinically and molecularly. Here, we review the evolution of classification schemes in B-cell lymphoma, noting the now standard WHO classification system that is based on immune cell-of-origin and molecular phenotypes. We review how lymphomas arise throughout the B-cell development process as well as the molecular and clinical features of prominent B-cell lymphomas. We provide an overview of the major progress that has occurred over the past decade in terms of our molecular understanding of these diseases. We discuss treatment options available and focus on a number of the diverse research tools that have been employed to improve our understanding of these diseases. We discuss the problem of heterogeneity in lymphomas and anticipate that the near future will bring significant advances that provide a measurable impact on NHL outcomes.

CD30 and ALK combination therapy has high therapeutic potency in RANBP2-ALK-rearranged epithelioid inflammatory myofibroblastic sarcoma

BACKGROUND

Epithelioid inflammatory myofibroblastic sarcoma (eIMS) is characterised by perinuclear ALK localisation, CD30 expression and early relapse despite crizotinib treatment. We aimed to identify therapies to prevent and/or treat ALK inhibitor resistance.

METHODS

Malignant ascites, from an eIMS patient at diagnosis and following multiple relapses, were used to generate matched diagnosis and relapse xenografts.

RESULTS

Xenografts were validated by confirmation of RANBP2-ALK rearrangement, perinuclear ALK localisation and CD30 expression. Although brentuximab-vedotin (BV) demonstrated single-agent activity, tumours regrew during BV therapy. BV resistance was associated with reduced CD30 expression and induction of ABCB1. BV resistance was reversed in vitro by tariquidar, but combination BV and tariquidar treatment only briefly slowed xenograft growth compared with BV alone. Combining BV with either crizotinib or ceritinib resulted in marked tumour shrinkage in both xenograft models, and resulted in prolonged tumour-free survival in the diagnosis compared with the relapse xenograft.

CONCLUSIONS

CD30 is a therapeutic target in eIMS. BV efficacy is limited by the rapid emergence of resistance. Prolonged survival with combination ALK and CD30-targeted-therapy in the diagnosis model provides the rationale to trial this combination in eIMS patients at diagnosis. This combination could also be considered for other CD30-positive, ALK-rearranged malignancies.

Development and Significance of Mouse Models in Lymphoma Research

PURPOSE OF REVIEW

Animal models have played an indispensable role in interpreting cancer gene functions, pathogenesis of disease, and in the development of innovative therapeutic approaches targeting aberrant biological pathways in human cancers.

RECENT FINDINGS

These models have guided the therapeutic targeting of cancer-causing mutations and paved the way for assessing anti-cancer drug responses and the preclinical development of immunotherapies. The mammalian models of cancer utilize genetically edited or transplanted mice that develop fairly accurate disease histopathology. The mouse model also allows us to study the effect of tumor microenvironment in the development of lymphoma. The emergence of patient-derived xenografts provides a better opportunity for recapitulating primary lymphoma characteristics and researching personalized drug therapy. In conclusion, the refinement and advancement of available mouse models in lymphoma significantly minimize the therapeutic translational failures in patients.

The spectrum of the cytopathological features of primary effusion lymphoma and human herpes virus 8-related lymphoproliferative disorders

INTRODUCTION

Human herpes virus 8-related lymphoproliferative disorders are a complex and heterogeneous group of entities and some of them are eminently diagnosed by cytopathology. In a routine laboratory, these lesions account for less than 1% of the effusion fluids samples. However, they represent up to 30% of all the lymphoma diagnosis from effusion cytological samples and their consideration in the diagnostic flow chart is mandatory, especially in human immunodeficiency virus-positive patients.

METHODS

A retrospective series of cytological specimens from cavity effusions (n = 605) were analysed. Five human herpes virus 8-related lymphoproliferative processes were recruited. A combination of morphological criteria (enhanced with May-Grünwald Giemsa staining), cell block-based immunocytochemistry and flow cytometry were undertaken for final characterisation.

RESULTS

The identification of malignant cells may be difficult. Some specimens are particularly rich, easily leading to suspect a lymphoproliferative process, whereas in other cases, the presence of abundant reactive mesothelial cells, histiocytes, neutrophils, small reactive T and B lymphocytes may obscure the neoplastic process. The biological behaviour may be very heterogeneous and a standardised therapy for these cases is still lacking, although some patients may benefit from antiretroviral therapy in a human immunodeficiency virus setting.

CONCLUSIONS

The present case series highlights some characteristic findings of these entities to reaffirm useful cytopathological diagnostic criteria, stressing the crucial role of the appropriate technical processing of effusion fluids to obtain the best performances.

Activity of brentuximab vedotin in AIDS-related primary effusion lymphoma

Brentuximab vedotin is active in primary effusion lymphoma, a rare CD30-positive lymphoma with an extremely poor prognosis.

Single-Chain Variable Fragment-Based Bispecific Antibodies: Hitting Two Targets with One Sophisticated Arrow

Despite the success of monoclonal antibodies (mAbs) to treat some disorders, the monospecific molecular entity of mAbs as well as the presence of multiple factors and pathways involved in the pathogenesis of disorders, such as various malignancies, infectious diseases, and autoimmune disorders, and resistance to therapy have restricted the therapeutic efficacy of mAbs in clinical use. Bispecific antibodies (bsAbs), by concurrently recognizing two targets, can partly circumvent these problems. Serial killing of tumor cells by bsAb-redirected T cells, simultaneous blocking of two antigens involved in the HIV-1 infection, and concurrent targeting of the activating and inhibitory receptors on B cells to modulate autoimmunity are part of the capabilities of bsAbs. After designing and developing a large number of bsAbs for years, catumaxomab, a full-length bsAb targeting EpCAM and CD3, was approved in 2009 to treat EpCAM-positive carcinomas besides blinatumomab, a bispecific T cell engager antibody targeting CD19 and CD3, which was approved in 2014 to treat relapsed or refractory acute lymphoblastic leukemia. Furthermore, approximately 60 bsAbs are under investigation in clinical trials. The current review aims at portraying different formats of the single-chain variable fragment (scFv)-based bsAbs and shedding light on the scFv-based bsAbs in preclinical development, different phases of clinical trials, and the market.

High-dose Therapy and Autologous Hematopoietic Cell Transplantation as Consolidation Treatment for Primary Effusion Lymphoma

BACKGROUND

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin lymphoma. The limited disease-free survival after chemotherapy has resulted in a poor prognosis. The outcomes data for high-dose therapy followed by autologous hematopoietic cell transplantation (auto-HCT) for PEL are limited owing to the rarity of the disease.

PATIENTS AND METHODS

The present study included 9 patients with PEL from 2 major academic centers. Of these patients, 4 had received auto-HCT after high-dose therapy. Of the 9 patients, 8 (89%) had immunodeficiency (7 with human immunodeficiency virus seropositivity; 1, a solid organ transplant recipient) at the diagnosis. Human herpesvirus-8 by immunohistochemistry was positive in 8 patients. Anthracycline-based combination chemotherapy was used as first-line treatment in 7 patients; 4 underwent auto-HCT after attaining first complete remission.

RESULTS

The median follow-up of the surviving patients was 25 months (95% confidence interval [CI], 8%-29%). The 2-year progression-free and overall survival for the 8 patients who had received treatment was 58% (95% CI, 22%-95%) and 73% (95% CI, 41%-100%), respectively. The 2-year progression-free and overall survival for the patients who had received auto-HCT was 50% (95% CI, 1%-99%) and 75% (95% CI, 33%-100%), respectively. Of the 4 auto-HCT recipients, all had been in first complete remission at the time of autografting. The cumulative incidence of relapse was 50% (95% CI, 19%-100%). No deaths were attributable to auto-HCT at 2 years after autografting.

CONCLUSION

Despite the small sample size, our data have shown that consolidative auto-HCT is safe and effective and should be considered for eligible patients with PEL after demonstration of an objective response to induction chemotherapy. However, the high relapse rate remains a concern and warrants the development of new strategies to mitigate post-transplantation relapse.

Overview of Targeted Drugs for Mature B-Cell Non-hodgkin Lymphomas

The improved knowledge of pathogenetic mechanisms underlying lymphomagenesis and the discovery of the critical role of tumor microenvironments have enabled the design of new drugs against cell targets and pathways. The Food and Drug Administration (FDA) has approved several monoclonal antibodies (mAbs) and small molecule inhibitors (SMIs) for targeted therapy in hematology. This review focuses on the efficacy results of the currently available targeted agents and recaps the main ongoing trials in the setting of mature B-Cell non-Hodgkin lymphomas. The objective is to summarize the different classes of novel agents approved for mature B-cell lymphomas, to describe in synoptic tables the results they achieved and, finally, to draw future scenarios as we glimpse through the ongoing clinical trials. Characteristics and therapeutic efficacy are summarized for the currently approved mAbs [i.e., anti-Cluster of differentiation (CD) mAbs, immune checkpoint inhibitors, chimeric antigen receptor (CAR) T-cell therapy, and bispecific antibodies] as well as for SMIs i.e., inhibitors of B-cell receptor signaling, proteasome, mTOR BCL-2 HDAC pathways. The biological disease profiling of B-cell lymphoma subtypes may foster the discovery of innovative drug strategies for improving survival outcome in lymphoid neoplasms, as well as the trade-offs between efficacy and toxicity. The hope for clinical advantages should carefully be coupled with mindful awareness of the potential pitfalls and the occurrence of uneven, sometimes severe, toxicities.

Chronic CD30 signaling in B cells results in lymphomagenesis by driving the expansion of plasmablasts and B1 cells

CD30 is expressed on a variety of B-cell lymphomas, such as Hodgkin lymphoma, primary effusion lymphoma, and a diffuse large B-cell lymphoma subgroup. In normal tissues, CD30 is expressed on some activated B and T lymphocytes. However, the physiological function of CD30 signaling and its contribution to the generation of CD30⁺ lymphomas are still poorly understood. To gain a better understanding of CD30 signaling in B cells, we studied the expression of CD30 in different murine B-cell populations. We show that B1 cells expressed higher levels of CD30 than B2 cells and that CD30 was upregulated in IRF4⁺ plasmablasts (PBs). Furthermore, we generated and analyzed mice expressing a constitutively active CD30 receptor in B lymphocytes. These mice displayed an increase in B1 cells in the peritoneal cavity (PerC) and secondary lymphoid organs as well as increased numbers of plasma cells (PCs). TI-2 immunization resulted in a further expansion of B1 cells and PCs. We provide evidence that the expanded B1 population in the spleen included a fraction of PBs. CD30 signals seemed to enhance PC differentiation by increasing activation of NF-κB and promoting higher levels of phosphorylated STAT3 and STAT6 and nuclear IRF4. In addition, chronic CD30 signaling led to B-cell lymphomagenesis in aged mice. These lymphomas were localized in the spleen and PerC and had a B1-like/plasmablastic phenotype. We conclude that our mouse model mirrors chronic B-cell activation with increased numbers of CD30⁺ lymphocytes and provides experimental proof that chronic CD30 signaling increases the risk of B-cell lymphomagenesis.

CD20-negative primary middle ear diffuse large B-cell lymphoma coexpressing MYC and BCL-2 secondary to acute lymphoblastic leukemia: A case report

RATIONALE

Second diffuse large B-cell lymphoma (DLBCL) after treatment of acute lymphoblastic leukemia (ALL) is uncommon. To our knowledge, primary middle ear DLBCL which presents CD20-negative and coexpression of MYC and BCL-2 has not been reported yet.

PATIENT CONCERNS

A 20-year-old Chinese man complained fever and weakness for 2 months. Subsequently bone marrow morphology and flow cytometry immunophenotype suggested ALL. Administrated with 9 cycles of multiagent combined chemotherapy, he felt right ear progressive hearing loss, otalgia, aural fullness. Otoendoscopic examination revealed a pitchy mass obstructing the right external auditory canal. Then the mass resection was performed for biopsy and immunohistochemistry examination.

DIAGNOSIS

The mass was diagnosed as DLBCL which was negative for CD20 and double expression of MYC and BCL-2.

INTERVENTIONS

Chemotherapy.

OUTCOMES

The patient eventually gave up and died of severe infection.

LESSONS

Although intensive chemotherapy has markedly improved the survival of ALL, more and more secondary cancers have been reported. In addition, primary middle ear lymphoma is much rare; hence, it is easy to be misdiagnosed. Furthermore, DLBCL with negative CD20 and double expression of MYC and BCL-2 is aggressive, which is characterized by chemotherapy resistance and inferior survival rates. We discuss this case aiming at raising awareness of tumors secondary to ALL and exploring the appropriate treatment options for the rare DLBCL.

Body Cavity-Based Lymphoma in a Country with Low Human Immunodeficiency Virus Prevalence: A Series of 17 Cases from the Consortium for Improving Survival of Lymphoma

Purpose

Primary effusion lymphoma (PEL) is a type of body cavity–based lymphoma (BCBL). Most patients with PEL are severely immunocompromised and seropositive for human immunodeficiency virus (HIV). We investigated the distinctive clinicopathologic characteristics of BCBL in a country with low HIV burden.

Materials and Methods

We retrospectively collected data on the clinicopathologic characteristics, treatments, and outcomes of 17 consecutive patients with BCBL at nine institutions in Korea.

Results

Latency-associated nuclear antigen 1 (LANA1) immunostaining indicated that six patients had PEL, six patients had human herpesvirus 8 (HHV8)-unrelated BCBL, and five patients had HHV8-unknown BCBL. The patients with PEL exhibited no evidence of immunodeficiency except for one who was HIV positive. One (20%) and four (80%) patients with PEL and six (100%) and zero (0%) patients with HHV8-unrelated BCBL were positive for CD20 and CD30 expression, respectively. The two patients with PEL (one HIV-positive and one HIV-negative patient) with the lowest proliferation activity as assessed by the Ki-67 labeling index survived for > 1 and > 4 years without chemotherapy, respectively, in contrast to the PEL cases in the literature, which mostly showed a high proliferation index and poor survival.

Conclusion

PEL mostly occurred in ostensibly immunocompetent individuals and had a favorable outcome in Korea. A watchful waiting approach may be applicable for managing HIV-seronegative patients with PEL with a low Ki-67 labeling index. A possible trend was detected among LANA1, CD20, and CD30 expression in BCBL.

Brentuximab vedotin as frontline treatment for HIV-related extracavitary primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive herpesvirus-8 (HHV-8) driven B cell non-Hodgkin's lymphoma (NHL) that is usually associated with human immunodeficiency virus (HIV) infection, and has a poor prognosis. PEL is comprised of two clinically distinct but pathologically similar variants: classic and extracavitary PEL. Based on retrospective series, treatment options include combined antiretroviral therapy (cART) in conjunction with chemotherapy regimens used in other forms of NHLs. Treatment outcomes with this approach are usually dismal and there is no standard of care. We present a case of a patient with HIV associated CD30+ extracavitary PEL unfit for multi-agent chemotherapy, who achieved a durable complete response with single agent brentuximab-vedotin and cART.

AIDS-Associated Malignancies

Malignancies were one of the earliest recognized manifestations that led to the description of the acquired immune deficiency syndrome (AIDS). The majority of cancers in AIDS patients are associated with coinfection with oncogenic viruses, such as Epstein-Barr virus, human herpesvirus 8, and human papillomavirus, with resulting malignancies occurring secondary to diminished immune surveillance against viruses and virus-infected tumor cells. Over 50% of AIDS lymphomas are associated with Epstein-Barr virus (EBV) and/or HHV8 infection. HHV8-associated diseases include Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). EBV is associated with several malignancies, including Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Coinfection with HIV and HPV is associated with an increased risk of various squamous cell carcinomas of epithelial tissues. HAART has significantly impacted the incidence, management, and prognosis of AIDS-related malignancies. In addition to changing the natural history of HIV infection in regard to incidence and survival, HAART has dramatically decreased the incidence of certain virally mediated HIV-associated malignancies such as KS and primary CNS lymphoma. The beneficial effects of HAART on these tumors are attributed to drug-mediated HIV suppression and immune reconstitution. However, HAART has had a less favorable impact on EBV- and HPV-related malignancies. This chapter presents an overview of HIV-associated malignancies mediated by HHV-8, EBV, and HPV, and reviews the effect of HAART on the epidemiology, presentation, treatment, and outcomes of these cancers.

Molecular Biology of EBV in Relationship to HIV/AIDS-Associated Oncogenesis

Herpesvirus-induced disease is one of the most lethal factors which leads to high mortality in HIV/AIDS patients. EBV, also known as human herpesvirus 4, can transform naive B cells into immortalized cells in vitro through the regulation of cell cycle, cell proliferation, and apoptosis. EBV infection is associated with several lymphoma and epithelial cancers in humans, which occurs at a much higher rate in immune deficient individuals than in healthy people, demonstrating that the immune system plays a vital role in inhibiting EBV activities. EBV latency infection proteins can mimic suppression cytokines or upregulate PD-1 on B cells to repress the cytotoxic T cells response. Many malignancies, including Hodgkin Lymphoma and non-Hodgkin's lymphomas occur at a much higher frequency in EBV positive individuals than in EBV negative people during the development of HIV infection. Importantly, understanding EBV pathogenesis at the molecular level will aid the development of novel therapies for EBV-induced diseases in HIV/AIDS patients.

Biology and management of primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare B-cell malignancy that most often occurs in immunocompromised patients, such as HIV-infected individuals and patients receiving organ transplantation. The main characteristic of PEL is neoplastic effusions in body cavities without detectable tumor masses. The onset of the disease is associated with latent infection of human herpes virus 8/Kaposi sarcoma–associated herpes virus, and the normal counterpart of tumor cells is B cells with plasmablastic differentiation. A condition of immunodeficiency and a usual absence of CD20 expression lead to the expectation of the lack of efficacy of anti-CD20 monoclonal antibody; clinical outcomes of the disease remain extremely poor, with an overall survival at 1 year of ∼30%. Although recent progress in antiretroviral therapy has improved outcomes of HIV-infected patients, its benefit is still limited in patients with PEL. Furthermore, the usual high expression of programmed death ligand 1 in tumor cells, one of the most important immune-checkpoint molecules, results in the immune escape of tumor cells from the host immune defense, which could be the underlying mechanism of poor treatment efficacy. Molecular-targeted therapies for the activating pathways in PEL, including NF-κB, JAK/STAT, and phosphatidylinositol 3-kinase/AKT, have emerged to treat this intractable disease. A combination of immunological recovery from immune deficiency, overcoming the immune escape, and the development of more effective drugs will be vital for improving the outcomes of PEL patients in the future.

Primary effusion lymphoma of the pleural space: Report of a rare complication of cardiac transplant with review of the literature

Primary effusion lymphoma (PEL) is a rare mature B-cell non-Hodgkin's lymphoma arising in body cavities and presenting with effusions. It has been described predominantly in patients with impaired immunity from the acquired immunodeficiency syndrome and is associated with the Human Herpesvirus-8 (HHV-8). Seldom has PEL been diagnosed in persons negative for the human immunodeficiency virus (HIV), and in such cases it has occurred primarily in the setting of posttransplant immunosuppression. We report an instructive case of a Caribbean-American HIV-negative orthotopic heart transplant recipient with a history of HHV-8-associated Kaposi's sarcoma who developed HHV-8 viremia and PEL of the pleural space early in the posttransplant course. This case highlights the importance of considering PEL in the differential diagnosis of a new pleural effusion in a transplant recipient at risk for HHV-8-associated disease.

Multi-targeted therapy of everolimus in Kaposi's sarcoma associated herpes virus infected primary effusion lymphoma

Kaposi's sarcoma associated herpes virus (KSHV) infected primary effusion lymphoma (PEL) is a rare aggressive form of non-Hodgkin's lymphoma of B cells. KSHV latent and lytic antigens modulate several host cellular signalling pathways especially mammalian target of rapamycin (mTOR), STAT-3 and nuclear factor-kappa B (NF-κB) for rapid tumor progression and immune evasion. Current chemotherapeutic strategies are becoming ineffective as they kill only dividing cells and inefficient to target molecular pathways crucial for active virus replication and its survival. In this study, we evaluated the efficacy of everolimus, an mTOR inhibitor in inducing apoptosis of PEL cells. Dose-dependent treatment of everolimus triggered mitochondria-mediated caspase-dependent apoptosis in PEL cells. Everolimus downregulated KSHV latent antigen expression with concurrent blocking of lytic reactivation for active virus replication. Everolimus also inhibited latent antigen mediated constitutively active STAT-3 and NF-κB signalling. We co-cultured everolimus treated PEL cells with immature dendritic cells and found activation of dendritic cells with increase in surface expression of CD86 and HLA-DR. As everolimus targets and disrupts KSHV antigens as well as antigen facilitated multiple signalling pathways necessary for KSHV survival and maintenance of infection with synchronised boosting of immune system against viral infection, it can be a better therapeutic approach towards treatment of PEL.

Primary effusion lymphoma: current perspectives

Primary effusion lymphoma (PEL) is a rare and aggressive disease, affecting a unique population of patients who are often elderly or immunocompromised. PEL is associated with human herpesvirus type-8 infection and most commonly presents as malignant effusions of the body cavities. Patients diagnosed with PEL often have a compromised immune system from secondary conditions such as HIV. Chemotherapy has traditionally been the cornerstone of treatment for patients with a good performance status and no significant comorbidities. However, an optimal regimen does not exist. Most patients with PEL experience a relapse after frontline therapy within 6-8 months and subsequently require further treatment. In recent years, our understanding of the molecular drivers and environmental factors affecting the pathogenesis of PEL has expanded. This review will discuss the pathogenesis of PEL and various management approaches available in the frontline and relapsed setting as well as targeted agents that have shown promise in this disease.

CD30 expression and survival in extranodal NK/T-cell lymphoma: a systematic review and meta-analysis

Background

The paradoxical reports about the prognostic value of the CD30 expression in extranodal NK/T-cell lymphoma (ENKTL) have restricted its further applications in clinical practice. To identify the common effects and the variation, we conducted this systematic review and meta-analysis.

Methods

PubMed, MEDLINE, Embase, and Web of Science were searched between January 1975 and 31 January 2017. The pooled hazard ratio was used to estimate the effect of the CD30 expression on overall survival. Bias was assessed by prespecified criteria referring to Reporting Recommendations for Tumor Marker Prognostic Studies and Newcastle-Ottawa Scale.

Results

Ten retrospective cohort studies with 310 patients are included. CD30 is associated with better overall survival significantly (HR 0.71, 95% CI 0.51 to 0.99, I² = 0%). A greater effect is observed among studies including participants predominant in regional involvement (HR 0.31, 95%CI 0.13 to 0.76, I² = 0%) compared with those in systemic involvement.

Conclusions

This study indicates that the CD30 expression is significantly associated with better prognosis in ENKTL, especially for patients with regional lymphoma involvement.

Brentuximab vedotin: clinical updates and practical guidance

Brentuximab vedotin (BV), a potent antibody-drug conjugate, targets the CD30 antigen. Owing to the remarkable efficacy shown in CD30-positive lymphomas, such as Hodgkin's lymphoma and systemic anaplastic large-cell lymphoma, BV was granted accelerated approval in 2011 by the US Food and Drug Administration. Thereafter, many large-scale trials in various situations have been performed, which led to extensions of the original indication. The aim of this review was to describe the latest updates on clinical trials of BV and the in-practice guidance for the use of BV.

The promising role of monoclonal antibodies for immunotherapy of the HIV-associated cancer, non-Hodgkin lymphoma

Association between HIV/AIDS and some of the cancers such as lymphomais is well known. Relative risk for developing non-Hodgkin lymphoma (NHL) increases 60-200 folds in HIV-infected individuals. Diffuse large B cell lymphoma (DLBCL), primary effusion lymphoma (PEL), Burkitt's lymphoma (BL) and Plasmablastic Lymphoma (PBL) are among the most frequent subtypes. During the last century, scientists found that the immune system could potentially detect and destroy cancer cells. Therefore, they started a new field of study, which is named immunotherapy. There are different immunotherapeutic methods, among which therapeutic antibodies, such as Brentuximabvedotin (Adcetris), Ibritumomabtiuxetan (Zevalin) and rituximab (Rituxan), used for treatment of NHLs showed promising results. In this article, we will review the immunotherapeutic option, monoclonal antibodies, for treatment of HIV-associated NHLs as well as their recent clinical status. We will also discuss the selective monoclonal antibody for each subtype of NHLs.

Viral Oncology: Molecular Biology and Pathogenesis

Oncoviruses are implicated in approximately 12% of all human cancers. A large number of the world's population harbors at least one of these oncoviruses, but only a small proportion of these individuals go on to develop cancer. The interplay between host and viral factors is a complex process that works together to create a microenvironment conducive to oncogenesis. In this review, the molecular biology and oncogenic pathways of established human oncoviruses will be discussed. Currently, there are seven recognized human oncoviruses, which include Epstein-Barr Virus (EBV), Human Papillomavirus (HPV), Hepatitis B and C viruses (HBV and HCV), Human T-cell lymphotropic virus-1 (HTLV-1), Human Herpesvirus-8 (HHV-8), and Merkel Cell Polyomavirus (MCPyV). Available and emerging therapies for these oncoviruses will be mentioned.

Management and Outcomes of HIV-Associated Primary Effusion Lymphoma: A Single Center Experience

BACKGROUND

Primary effusion lymphoma (PEL) is a rare malignancy usually associated with HIV infection. Management and outcomes are poorly understood.

METHODS

The medical records of all patients diagnosed with HIV-associated PEL at our institution between 1999 and 2014 were reviewed. Patients were followed till death, treatment failure or loss of follow-up.

RESULTS

Twelve patients with PEL were identified during the 15 year study period; 9 had HIV infection. All 9 were male; median age was 45 years. All presented with local symptoms and were diagnosed with PEL a median of 11 years after HIV diagnosis. Location was pleural (3), pericardial (3), peritoneal (1) and extracavitatory (2). By definition, all had Ann Arbor stage 4 at diagnosis. Median follow-up was 34 months. Two patients had poor performance status and were unable to get chemotherapy. Seven patients had a complete remission (CR) and two died within 1 month of diagnosis. The median CD4 levels at PEL diagnosis in patients with poor versus good outcomes were 54 cells/mm3 (range, 26-82 cells/mm3) and 211 cells/mm3 (range, 73-800 cells/mm3). In contrast, the median lactate dehydrogenase (LDH) levels at PEL diagnosis with poor versus good prognosis were 1074 U/L (range, 703-1445 U/L) and 283 U/L (range, 156-760 U/L).

CONCLUSIONS

Given its rarity, our knowledge of PEL relies solely on case reports and case series. Prompt HAART and chemotherapy may be effective in HIV- associated PEL and good outcomes are possible. LDH and CD4 may be possible prognostic factors in PEL.

Survival of patients with CD20-negative variants of large B-cell lymphoma: an analysis of the National Cancer Data Base

Using records from the National Cancer Data Base, we studied overall survival of CD20-negative variants of diffuse large B-cell lymphoma (DLBCL): primary effusion (PEL, N = 228), plasmablastic (PBL, N = 481), ALK-positive large B-cell (ALK + LBLC, N = 15), and human herpesvirus-8-positive DLBCL (HHV8 + DLBCL, N = 77). Three-year survival was 27% for PEL, 40% for PBL, 34% for ALK + LBCL, and 63% for HHV8 + DLBCL. Compared with unspecified DLBCL, and adjusting for clinical characteristics (including the HIV status), survival was significantly worse for PEL (hazard ratio [HR], 1.58; 95% confidence interval [CI], 1.31-1.90), PBL (HR 1.66; 95% CI, 1.41-1.95), and ALK + LBCL (HR, 2.70; 95% CI, 1.27-5.75), but not for HHV8 + DLBCL (HR, 0.89; 95% CI, 0.54-1.45). The HIV status was not an independent prognostic factor in PEL, PBL, or HHV8 + DLBCL. Advanced stage was prognostic for PBL (p = .0002), but not for ALK + LBCL (p = .96), or HHV8 + DLBCL (p = .28). In PEL and PBL survival significantly differed according to primary site. Novel therapeutic approaches are urgently needed for these rare diseases.

Animal models of tumorigenic herpesviruses--an update

Any one model system, be it culture or animal, only recapitulates one aspect of the viral life cycle in the human host. By providing recent examples of animal models for Epstein-Barr virus and Kaposi sarcoma-associated herpesvirus, we would argue that multiple animal models are needed to gain a comprehensive understanding of the pathogenesis associated with human oncogenic herpesviruses. Transgenic mice, homologous animal herpesviruses, and tumorgraft and humanized mouse models all complement each other in the study of viral pathogenesis. The use of animal model systems facilitates the exploration of novel anti-viral and anti-cancer treatment modalities for diseases associated with oncogenic herpesviruses.

Interleukin 21 - its potential role in the therapy of B-cell lymphomas

Interleukin-21 (IL-21), a member of IL-2 cytokine family, has pleotropic biological effects on lymphoid and myeloid cells. During the past 15 years, since the discovery of IL-21, great advances have been made regarding its biological activity and the mechanisms controlling IL-21-mediated cellular responses, especially in hematological malignancies. Preclinical studies have shown that IL-21R is expressed on healthy and neoplastic B-cells and exogenous IL-21 can induce direct apoptosis of IL-21R expressing B-cell non-Hodgkin lymphomas (NHL), making it a potentially attractive anti-lymphoma therapy. However, in some hematological malignancies such as multiple myeloma, Hodgkin lymphoma and Burkitt lymphoma, IL-21 can induce proliferation of neoplastic B-cells. In NHL, the underlying mechanism of cell death was found to be different between the various subtypes, including activation of different JAK/STAT signal transduction pathways or other factors. Immunomodulatory effects of IL-21 have also been reported to contribute to its anti-tumor effects as described by earlier studies in solid tumors and B-cell associated malignancies. These effects are predominantly mediated by IL-21's ability to activate cytolytic activities by NK-cells and CD4⁺/CD8⁺ T-cells. In this review, we provide an overview of IL-21's effects in NHL, results from clinical trials utilizing IL-21, and propose how IL-21 can be therapeutically exploited for treating these lymphomas.

Role of the tumor microenvironment in regulating apoptosis and cancer progression

Apoptosis is a gene-directed program that is engaged to efficiently eliminate dysfunctional cells. Evasion of apoptosis may be an important gate to tumor initiation and therapy resistance. Like any other developmental program, apoptosis can be disrupted by several genetic aberrations driving malignant cells into an uncontrolled progression and survival. For its sustained growth, cancer develops in a complex environment, which provides survival signals and rescues malignant cells from apoptosis. Recent studies have clearly shown a wide interaction between tumor cells and their microenvironment, confirming the influence of the surrounding cells on tumor expansion and invasion. These non-malignant cells not only intensify tumor cells growth but also upgrade the process of metastasis. The strong crosstalk between malignant cells and a reactive microenvironment is mediated by soluble chemokines and cytokines, which act on tumor cells through surface receptors. Disturbing the microenvironment signaling might be an encouraging approach for patient's treatment. Therefore, the ultimate knowledge of "tumor-microenvironment" interactions facilitates the identification of novel therapeutic procedures that mobilize cancer cells from their supportive cells. This review focuses on cancer progression mediated by the dysfunction of apoptosis and by the fundamental relationship between tumor and reactive cells. New insights and valuable targets for cancer prevention and therapy are also presented.

Brentuximab: a major advance in treatment of CD30-positive malignancies

Antibody-directed therapies allow greater selectivity in targeting of tumor associated antigens and spare normal cells. Brentuximab vedotin is an anti-CD30 antibody–drug conjugate. It has demonstrated impressive activity in the treatment of refractory and or relapsed Hodgkin's lymphoma, anaplastic large cell lymphoma and other CD30+ lymphoid malignancies. Several ongoing trials are testing the potential use of brentuximab vedotin for treatment of various CD30+ and CD30- malignancies in the setting of high-risk untreated disease. It is being tested in combination with chemotherapy, and testing in combination with immune therapy is also planned. CD30 plays a pivotal role in immune regulation and is also an attractive new target for intervention in the setting of select auto-immune diseases, as well as graft versus host disease.

Identification of the Ki-1 antigen (CD30) as a novel therapeutic target in systemic mastocytosis

The Ki-1 antigen (CD30) is an established therapeutic target in patients with Hodgkin lymphoma and anaplastic large-cell lymphoma. We have recently shown that CD30 is expressed abundantly in the cytoplasm of neoplastic mast cells (MCs) in patients with advanced systemic mastocytosis (SM). In the current study, we asked whether CD30 is expressed on the surface of neoplastic MCs in advanced SM, and whether this surface structure may serve as therapeutic target in SM. As assessed by flow cytometry, CD30 was found to be expressed on the surface of neoplastic MCs in 3 of 25 patients (12%) with indolent SM, 4 of 7 patients (57%) with aggressive SM, and 4 of 7 patients (57%) with MC leukemia. The immature RAS-transformed human MC line MCPV-1.1 also expressed cell surface CD30, whereas the KIT-transformed MC line HMC-1.2 expressed no detectable CD30. The CD30-targeting antibody-conjugate brentuximab-vedotin inhibited proliferation in neoplastic MCs, with lower IC50 values obtained in CD30(+) MCPV-1.1 cells (10 µg/mL) compared with CD30(-) HMC-1.2 cells (>50 µg/mL). In addition, brentuximab-vedotin suppressed the engraftment of MCPV-1.1 cells in NSG mice. Moreover, brentuximab-vedotin produced apoptosis in all CD30(+) MC lines tested as well as in primary neoplastic MCs in patients with CD30(+) SM, but did not induce apoptosis in neoplastic MCs in patients with CD30(-) SM. Furthermore, brentuximab-vedotin was found to downregulate anti-IgE-induced histamine release in CD30(+) MCs. Finally, brentuximab-vedotin and the KIT D816V-targeting drug PKC412 produced synergistic growth-inhibitory effects in MCPV-1.1 cells. Together, CD30 is a promising new drug target for patients with CD30(+) advanced SM.

Human Exportin-1 is a Target for Combined Therapy of HIV and AIDS Related Lymphoma

Infection with HIV ultimately leads to advanced immunodeficiency resulting in an increased incidence of cancer. For example primary effusion lymphoma (PEL) is an aggressive non-Hodgkin lymphoma with very poor prognosis that typically affects HIV infected individuals in advanced stages of immunodeficiency. Here we report on the dual anti-HIV and anti-PEL effect of targeting a single process common in both diseases. Inhibition of the exportin-1 (XPO1) mediated nuclear transport by clinical stage orally bioavailable small molecule inhibitors (SINE) prevented the nuclear export of the late intron-containing HIV RNA species and consequently potently suppressed viral replication. In contrast, in CRISPR-Cas9 genome edited cells expressing mutant C528S XPO1, viral replication was unaffected upon treatment, clearly demonstrating the anti-XPO1 mechanism of action. At the same time, SINE caused the nuclear accumulation of p53 tumor suppressor protein as well as inhibition of NF-κB activity in PEL cells resulting in cell cycle arrest and effective apoptosis induction. In vivo, oral administration arrested PEL tumor growth in engrafted mice. Our findings provide strong rationale for inhibiting XPO1 as an innovative strategy for the combined anti-retroviral and anti-neoplastic treatment of HIV and PEL and offer perspectives for the treatment of other AIDS-associated cancers and potentially other virus-related malignancies.

Immunomodulatory drugs target IKZF1-IRF4-MYC axis in primary effusion lymphoma in a cereblon-dependent manner and display synergistic cytotoxicity with BRD4 inhibitors

Primary effusion lymphoma (PEL) is an aggressive type of non-Hodgkin lymphoma localized predominantly in body cavities. Kaposi’s sarcoma-associated herpes virus is the causative agent of PEL. PEL is an incurable malignancy and has extremely poor prognosis when treated with conventional chemotherapy. Immunomodulatory drugs (IMiDs) lenalidomide and pomalidomide are FDA approved drugs for the treatment of various ailments. IMiDs display pronounced anti-proliferative effect against majority of PEL cell lines within their clinically achievable concentrations, by arresting cells at G₀/G₁ phase of cell-cycle, and without any induction of KSHV lytic-cycle reactivation. Although microarray examination of PEL cells treated with lenalidomide revealed activation of interferon (IFN) signaling, blocking the IFN pathway did not block the anti-PEL activity of IMiDs. The anti-PEL effects of IMiDs involved cereblon-dependent suppression of IRF4 and rapid degradation of IKZF1, but not IKZF3. Small hairpin-RNA (shRNA) mediated knockdown of MYC enhanced the cytotoxicity of IMiDs. Bromodomain and extraterminal domain (BET) proteins are epigenetic readers which perform a vital role in chromatin remodeling and transcriptional regulation. BRD4, a widely expressed transcriptional coactivator, belongs to BET family of proteins, which has been shown to co-occupy the super-enhancers associated with MYC. Specific BRD4 inhibitors were developed which suppress MYC transcriptionally. Lenalidomide displayed synergistic cytotoxicity with several structurally distinct BRD4 inhibitors (JQ-1, IBET151, and PFI-1). Furthermore, combined administration of lenalidomide and BRD4 inhibitor JQ-1 significantly increased the survival of PEL bearing NOD.SCID mice in an orthotopic xenograft model as compared to either agent alone. These results provide compelling evidence for clinical testing of IMiDs alone and in combination with BRD4 inhibitors for PEL.

Brentuximab vedotin for treatment of relapsed or refractory malignant lymphoma: results of a systematic review and meta-analysis of prospective studies

Background

Recently, brentuximab vedotin has become a promising therapeutic approach for CD30-positive hematological malignancies, but its role in other relapsed or refractory malignant lymphoma needs to be proven. Brentuximab vedotin was demonstrated effective, but no study has summarized the concrete effect of brentuximab vedotin in malignant lymphoma. To truly know the role of brentuximab vedotin, we performed a systematic review of the literature and a meta-analysis of all known prospective trials, to assess the value of brentuximab vedotin for patients with relapsed and refractory malignant lymphoma.

Methods and materials

This was a systematic review of publications indexed in the PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and ISI Web of Knowledge performed on February 10, 2015. Six studies, including 302 patients were identified. Meta-analyses were carried out to calculate the objective response rate (ORR), complete response rate (CRR), and partial response rate (PRR) of brentuximab vedotin for malignant lymphoma.

Results

In patients with malignant lymphoma, ORR was 0.61, CRR was 0.38, and PRR was 0.51. High heterogeneity between studies was observed, and funnel plots were not symmetrical, which means that publication bias existed. Brentuximab vedotin was generally well-tolerated by patients reported in the included studies; adverse effects also occurred, but they were considered manageable.

Conclusion

Our analysis revealed a promising benefit of brentuximab vedotin in the treatment of relapsed and refractory malignant lymphoma. Larger sample of randomized controlled clinical trials are needed in the future.

Brentuximab vedotin for relapsed or refractory Hodgkin's lymphoma

Brentuximab vedotin is a promising antibody-drug conjugate (ADC) targeting CD30 of tumor cells. It selectively delivers monomethyl auristatin E (MMAE) into CD30-expressing cells and induces tumor cell apoptosis. Various clinical trials have provided evidence that it is effective in relapsed or refractory Hodgkin's lymphoma (HL), and it has also shown its advantages in other CD30-positive lymphomas. In this review, we focus on the structure, mechanisms, and pharmacokinetics of brentuximab vedotin. We also summarize clinical trials with brentuximab vedotin and make recommendations for brentuximab vedotin in the treatment of relapsed or refractory HL.

Role of CD30 targeting in malignant lymphoma

CD30 is an important therapeutic target for the treatment of malignant lymphomas. CD30 is a member of the TNF cell receptor superfamily and is highly expressed in a variety of lymphoma subsets, including Hodgkin lymphoma and anaplastic large cell lymphoma. Initial studies evaluated the safety and efficacy of several monoclonal antibodies targeting CD30, with limited success. More recently, the anti-CD30 drug-conjugate brentuximab vedotin produced high response rates with an excellent safety profile. These results lead to the approval of brentuximab vedotin for the treatment of patients with relapsed Hodgkin lymphoma and anaplastic large cell lymphoma. Current studies are focusing on incorporating brentuximab vedotin in front-line regimens and expanding its potential clinical utility in other CD30-expressing malignancies.