Effective treatment with the selective cytokine inhibitor BNZ-1 reveals the cytokine dependency of T-LGL leukemia.

T-cell large granular lymphocytic leukemia (T-LGLL) is a clonal proliferation of cytotoxic T lymphocytes that can result in severe neutropenia, anemia, and bone marrow failure. Strong evidence from patients and mouse models demonstrate the critical role of interleukin-15 (IL-15) in T-LGLL pathogenesis. BNZ-1 is a pegylated peptide that selectively inhibits the binding of IL-15 and other γc cytokines to their cellular receptor complex, which has demonstrated efficacy in ex vivo T-LGLL cells and transgenic mice in preclinical studies. We conducted a phase 1/2 trial of BNZ-1 in patients with T-LGLL who had hematocytopenias (anemia or neutropenia) and required therapy. Clinical responses were assessed using hematologic parameters (improvement in hematocytopenias) based on response criteria from the Eastern Cooperative Oncology Group 5998 T-LGLL trial. BNZ-1 demonstrated clinical partial responses in 20% of patients with T-LGLL with minimal toxicity and the maximum tolerated dose was not reached. Furthermore, T-LGL leukemic cells showed significantly increased apoptosis in response to BNZ-1 treatment as early as day 2, including in clinical nonresponders, with changes that remained statistically different from baseline throughout treatment (P < .005). We report first-in-human proof that T-LGL leukemic cells are dependent on IL-15 and that intervention with IL-15 inhibition with BNZ-1 in patients with T-LGLL shows therapeutic effects, which carries important implications for the understanding of the pathogenesis of this disease. This trial was registered at www.clinicaltrials.gov as #NCT03239392.

The role of signaling lymphocyte activation molecule family receptors in hematologic malignancies.

PURPOSE OF REVIEW: In this review, we provide an overview of the current understanding of SLAM-family receptors in hematologic malignancies. We highlighted their contribution to the disease pathogenesis and targeting strategies to improve therapeutic outcomes. RECENT FINDINGS: Emerging studies have reported the tumor-promoting role of SLAM-family receptors in various hematologic malignancies, including chronic lymphocytic leukemia, acute myeloid leukemia, and multiple myeloma. Specifically, they regulate the interaction between malignant cells and the tumor microenvironment to promote apoptosis resistance, therapeutic resistance, impairment of antitumor and tumor progression. SUMMARY: SLAM-family receptors promote the progression of hematologic malignancies by regulating the interaction between malignant cells and the tumor microenvironment. This provides the rationale that SLAM-targeted therapies are appealing strategies to enhance therapeutic outcomes in patients.

Targeting macrophages for enhancing CD47 blockade-elicited lymphoma clearance and overcoming tumor-induced immunosuppression.

Tumor-associated macrophages (TAMs) are often the most abundant immune cells in the tumor microenvironment (TME). Strategies targeting TAMs to enable tumor cell killing through cellular phagocytosis have emerged as promising cancer immunotherapy. Although several phagocytosis checkpoints have been identified, the desired efficacy has not yet been achieved by blocking such checkpoints in preclinical models or clinical trials. Here, we showed that late-stage non-Hodgkin lymphoma (NHL) was resistant to therapy targeting phagocytosis checkpoint CD47 due to the compromised capacity of TAMs to phagocytose lymphoma cells. Via a high-throughput screening of the US Food and Drug Administration-approved anticancer small molecule compounds, we identified paclitaxel as a potentiator that promoted the clearance of lymphoma by directly evoking phagocytic capability of macrophages, independently of paclitaxel's chemotherapeutic cytotoxicity toward NHL cells. A combination with paclitaxel dramatically enhanced the anticancer efficacy of CD47-targeted therapy toward late-stage NHL. Analysis of TME by single-cell RNA sequencing identified paclitaxel-induced TAM populations with an upregulation of genes for tyrosine kinase signaling. The activation of Src family tyrosine kinases signaling in macrophages by paclitaxel promoted phagocytosis against NHL cells. In addition, we identified a role of paclitaxel in modifying the TME by preventing the accumulation of a TAM subpopulation that was only present in late-stage lymphoma resistant to CD47-targeted therapy. Our findings identify a novel and effective strategy for NHL treatment by remodeling TME to enable the tumoricidal roles of TAMs. Furthermore, we characterize TAM subgroups that determine the efficiency of lymphoma phagocytosis in the TME and can be potential therapeutic targets to unleash the antitumor activities of macrophages.

Identifying unmet needs and challenges in the definition of a plaque in mycosis fungoides: An EORTC-CLTG/ISCL survey.

BACKGROUND: Consensus about the definition and classification of 'plaque' in mycosis fungoides is lacking. OBJECTIVES: To delineate a comprehensive view on how the 'plaque' entity is defined and managed in clinical practice; to evaluate whether the current positioning of plaques in the TNMB classification is adequate. METHODS: A 12-item survey was circulated within a selected panel of 22 experts (pathologists, dermatologists, haematologists and oncologists), members of the EORTC and International Society for Cutaneous Lymphoma. The questionnaire discussed clinical and histopathological definitions of plaques and its relationship with staging and treatment. RESULTS: Total consensus and very high agreement rates were reached in 33.3% of questions, as all panellists regularly check for the presence of plaques, agree to evaluate the presence of plaques as a potential separate T class, and concur on the important distinction between plaque and patch for the management of early-stage MF. High agreement was reached in 41.7% of questions, since more than 50% of the responders use Olsen's definition of plaque, recommend the distinction between thin/thick plaques, and agree on performing a biopsy on the most infiltrated/indurated lesion. High divergence rates (25%) were reported regarding the possibility of a clinically based distinction between thin and thick plaques and the role of histopathology to plaque definition. CONCLUSIONS: The definition of 'plaque' is commonly perceived as a clinical entity and its integration with histopathological features is generally reserved to specific cases. To date, no consensus is achieved as for the exact definition of thin and thick plaques and current positioning of plaques within the TNMB system is considered clinically inadequate. Prospective studies evaluating the role of histopathological parameters and other biomarkers, as well as promising diagnostic tools, such as US/RM imaging and high-throughput blood sequencing, are much needed to fully integrate current clinical definitions with more objective parameters.

Expression of immune checkpoint molecules programmed death protein 1, programmed death-ligand 1 and inducible T-cell co-stimulator in mycosis fungoides and Sézary syndrome: association with disease stage and clinical outcome.

BACKGROUND: The relationship between immune checkpoint status and disease outcome is a major focus of research in cutaneous T-cell lymphoma (CTCL), a disfiguring neoplastic dermatological disorder. Mycosis fungoides (MF) and Sézary syndrome (SS) are the two most common types of CTCL. OBJECTIVES: The aim was to evaluate the immune checkpoint markers programmed death protein 1 (PD1), inducible T-cell co-stimulator (ICOS) and programmed death-ligand 1 (PD-L1) in skin biopsies from patients with CTCL relative to disease stage and overall survival. METHODS: This consecutive case series enrolled 47 patients: 57% had stage IA-IIA disease and 43% had stage IIB-IVA2 disease (including seven with SS). RESULTS: PD1, PD-L1 and ICOS expression was seen in all biopsies. Notably, PD-L1 was predominantly expressed on histiocytes/macrophages, but focal expression on CTCL cells was seen. High expression of either ICOS or PD-L1 was associated with advanced-stage disease (P = 0·007 for both) and with the appearance of large-cell transformation (LCT), a histopathological feature associated with a poor prognosis (ICOS: P = 0·02; PD-L1: P = 0·002). PD1 expression was not significantly associated with disease stage (P = 0·12) or LCT (P = 0·49), but expression was high in SS biopsies. A high combined checkpoint marker score (PD1, PD-L1 and ICOS) was associated with advanced-stage disease (P = 0·001), LCT (P = 0·021) and lower overall survival (P = 0·014). CONCLUSIONS: These findings demonstrate the existence of a complex immunoregulatory microenvironment in CTCL and support the development of immunotherapies targeting ICOS and PD-L1 in advanced disease.

Emerging drugs for the treatment of cutaneous T-cell lymphoma.

INTRODUCTION: Cutaneous T cell lymphoma (CTCL) is a rare and incurable group of non-Hodgkin lymphomas that manifest as patches, plaques, tumors, and/or erythroderma in the skin. Standard skin-directed therapies for CTCL are effective in patients with indolent early-stage disease, but more advanced/refractory stage patients require systemic therapies. However, none of the treatments are considered curative and most patients suffer from relapses. Biologic therapies and immunotherapy provide novel treatment options for patients with advanced or refractory disease. AREAS COVERED: This review provides a discussion of recently approved biological and novel therapeutics that are actively developed for the management of the heterogeneous group of CTCL. EXPERT OPINION: Mogamulizumab and brentuximab vedotin have reached the market and are approved for the treatment of CTCL, providing valuable options. Additionally, therapies utilizing immune checkpoint inhibitors, miRNA inhibitors, and peptide inhibitors show promising results in clinical trials. Durvalumab, pembrolizumab, TTI-621, BNZ-1, and MRG-106 are several of the emerging treatments still in trials. Further combinatorial studies are needed as none of the treatments have demonstrated long-term remissions.

Post hoc Analysis of a Randomized, Controlled, Phase 2 Study to Assess Response Rates with Chlormethine/Mechlorethamine Gel in Patients with Stage IA-IIA Mycosis Fungoides.

BACKGROUND: Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma. Patients can be treated using chlormethine gel, a skin-directed therapy developed and approved for MF. In the randomized, controlled 201 trial, chlormethine gel was found to be noninferior to equal-strength chlormethine ointment. However, there remains a need to gain more insight into outcome measures after treatment. OBJECTIVE: The aim of this study was to further investigate the potential of chlormethine gel treatment through a novel post hoc analysis of the 201 trial data (NCT00168064). METHODS: Patients were randomized to chlormethine gel or ointment; response assessments included Composite Assessment of Index Lesion Severity (CAILS) and total body surface area (BSA). In this post hoc analysis, additional subgroup response analyses were performed for stage IA/IB-IIA MF. Very good partial response (75 to <100% improvement) was included as an additional response category. Time to response and overall response trends were determined. Finally, multivariate time-to-event analyses were performed to determine whether associations were observed between treatment frequency, response, and adverse events. RESULTS: Response rates were significantly higher for patients with stage IA MF for CAILS (intent-to-treat [p = 0.0014] and efficacy-evaluable [EE; p = 0.0036] populations) and BSA (EE population [p = 0.0488]) treated with gel versus ointment. Time to first CAILS response and response trends were better for all-stage gel-treated patients overall. No association was seen between treatment frequency and response or occurrence of adverse events at the following visit. An association was observed between the occurrence of contact dermatitis and improved clinical response at the next visit (p = 0.0001). CONCLUSION: This post hoc analysis shows that treatment with chlormethine gel may result in higher and faster response rates compared with chlormethine ointment, which confirms and expands results reported in the original analysis. The incidence of contact dermatitis may potentially be a prognostic indicator for clinical response; this needs to be confirmed in a larger population.

The impact of gender, age, race/ethnicity, and stage on quality of life in a spectrum of cutaneous lymphomas.

PURPOSE: Cutaneous lymphomas (CLs) are a group of rare, potentially disfiguring and disabling cancers that can have a significant impact on quality of life (QoL). While previous studies have shown that mycosis fungoides (MF) and Sézary syndrome (SS) impair QoL, the effect of other types of CL on QoL has not been evaluated. OBJECTIVE: To determine the impact of disease on QoL in all CL patients and to assess how QoL between the CL sub-types varies by demographic and clinical factors. METHODS: The Cutaneous Lymphoma Distress Questionnaire (CL-DQ) was used to assess QoL. All CL patients seen in a multidisciplinary CL clinic were screened for eligibility. Questionnaire responses were collected over a 22-month period between 2017 and 2019. A cross-sectional analysis of CL-DQ scores from an initial visit was performed to determine the effect of disease on QoL across CL sub-types and the potential impact of patient demographics, CL sub-type, and type of treatment. RESULTS: The study population consisted of 151 patients presenting with distinct types of cutaneous B- and T-cell lymphomas. Notable across the study population were the findings of frustration (44%), worry about progress/spread (43%), itching/pruritus (32%), and embarrassment/shame (28%). QoL was found to be most negatively affected in SS patients, females, younger patients, Black patients, and those with advanced stages of MF/SS. CONCLUSIONS: Impairment of QoL due to CL correlates with gender, age, race/ethnicity, and stage of MF/SS. While the negative impact on QoL is most pronounced in SS patients, other CL sub-types also affect QoL and impact psychosocial distress. Our findings highlight the need for QoL assessment in all CL patients and further examination of disparities noted across demographic groups.

The role of myeloid-derived suppressor cells in hematologic malignancies.

PURPOSE OF REVIEW: This article focuses on the immunosuppressive impact of myeloid-derived suppressor cells (MDSCs) and the potential clinical implications in hematological malignancies. RECENT FINDINGS: MDSCs play a critical role in the regulation of the immune response in cancer. They inhibit activation of adaptive immune response and as a result foster the growth of the malignancy. Recent studies have shown that MDSCs serve as prognostic biomarkers and as targets for cancer immunotherapy. Preclinical and clinical studies have identified new approaches to deplete MDSC populations and inhibit MDSC function with combination immunomodulatory therapies including chemotherapeutic agents with immune checkpoint-directed treatment. SUMMARY: A broad spectrum of publications indicate that direct targeting of MDSCs may abrogate their protumorigenic impact within the tumor microenvironment through activation of the adaptive immune response.

Targeting microRNA in hematologic malignancies.

PURPOSE OF REVIEW: MiRNAs are critical regulators for gene expression. Numerous studies have revealed how miRNAs contribute to the pathogenesis of hematologic malignancies. RECENT FINDINGS: The identification of novel miRNA regulatory factors and pathways crucial for miRNA dysregulation has been linked to hematologic malignancies. miRNA expression profiling has shown their potential to predict outcomes and treatment responses. Recently, targeting miRNA biogenesis or pathways has become a promising therapeutic strategy with recent miRNA-therapeutics being developed. SUMMARY: We provide a comprehensive overview of the role of miRNAs for diagnosis, prognosis, and therapeutic potential in hematologic malignancies.

Primary Cutaneous T-Cell Lymphomas: Mycosis Fungoides and Sezary Syndrome.

Mycosis fungoides and Sézary syndrome are the most common subtypes of all primary cutaneous lymphomas and represent complex diseases that require a multidisciplinary assessment by dermatologists, oncologists, and pathologists. Staging and work-up are critical to guarantee an optimal treatment plan that includes skin-directed and/or systemic regimens depending on the clinical stage, tumor burden, drug-related side effect profile, and patient comorbidities. However, there is no cure and patients frequently relapse, requiring repeated treatment courses for disease control. The study of the tumor microenvironment and molecular mechanisms of these rare neoplasms may assist in the development of new immune therapies providing promising treatment approaches tailored for patients with relapse/refractory disease.

CD30-Positive Lymphoproliferative Disorders.

Primary cutaneous CD30-positive lymphoproliferative disorders (CD30+ LPD) encompass lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (pcALCL), and borderline lesions [1]. CD30+ LPD are the second most common cutaneous T-cell lymphomas (CTCL) after mycosis fungoides (MF) and represent approximately 25% of all CTCL cases [2]. Their common phenotypic hallmark is an expression of the CD30 antigen, a cytokine receptor belonging to the tumor necrosis factor (TNF) receptor superfamily. Both LyP and pcALCL show numerous clinical, histological and immunophenotypic variants, and generally have an indolent course with a favorable prognosis. Overlapping features of LyP and pcALCL with other CD30+ T-cell lymphomas, inflammatory, and/or infectious conditions emphasize the importance of careful clinicopathologic correlation and staging.

Relief of intractable pruritus with romidepsin in patients with cutaneous T-cell lymphoma: A series of four cases.

Cutaneous T-cell lymphomas (CTCL) are a relatively rare and heterogeneous group of non-Hodgkin lymphomas that typically present in the skin. The majority of patients with CTCL experience pruritus, which can interfere with daily activities, significantly impact quality of life, and is typically uncontrolled by standard anti-itch therapies. Several lymphoma treatments have reported anti-pruritic effects including romidepsin, a potent class 1 selective histone deacetylase inhibitor approved for the treatment of patients with CTCL who have had at least one prior systemic therapy. Here, we describe the cases of four patients with debilitating and refractory pruritus that were resolved with romidepsin. Resolution of pruritus was observed in both clinical responders and nonresponders, and dose modification was used successfully to manage adverse events and for maintenance treatment. The potential for pruritus relief with romidepsin should be considered when treating patients with CTCL.

Targeting CD47 as a cancer therapeutic strategy: the cutaneous T-cell lymphoma experience.

PURPOSE OF REVIEW: To describe the relevance of CD47 in the tumor microenvironment and summarize data on anti-CD47 therapies, including its role in cutaneous T-cell lymphoma (CTCL). RECENT FINDINGS: CD47 is expressed on all normal cells and targets SIRPα on the surface of myeloid cells. However, CD47 is found to be overexpressed on cancer cells. CD47-SIRPα interaction inhibits macrophage phagocytosis, allowing cancer cells to escape immune surveillance. Current focus in immunotherapy has been targeted toward inhibiting CD47-SIRPα interaction via anti-CD47 antibodies. This activates innate immunity, promoting cancer cell destruction by macrophages. It also activates adaptive immunity resulting in antigen-presentation, mostly by dendritic cells, leading to antitumor cytotoxic reactions. Current CD47 antagonists undergoing clinical trials include Hu5F9 (an anti-CD47 antibody that directly inhibits the CD47-SIRPα interaction) and TTI-621, (a fusion protein composed of CD47 binding domain of human SIRPα and linked to the Fc region of IgG1). These agents have continued to show strong efficacy against solid and hematological tumors. SUMMARY: In the CTCL tumor microenvironment, increased immune checkpoint inhibition expression via CD47 bound to SIRPα correlates with a more advanced disease state. Continued success in treating these patients requires further studies on CD47 antagonists, specifically when combined with other antibodies.

Progression of undiagnosed cutaneous lymphoma after anti-tumor necrosis factor-alpha therapy.

BACKGROUND: Cutaneous lymphoma diagnosed after anti-tumor necrosis factor-α therapy (anti-TNF-α) has been reported in the literature, yet a clear link between both events remains elusive. OBJECTIVE: To review our experience with cutaneous lymphoma diagnosed during or after the use of anti-TNF-α therapies. METHODS: This is a multicenter retrospective study and a literature review. RESULTS: A total of 22 cases, including 20 cutaneous T-cell lymphomas (CTCLs) and 2 cutaneous B-cell lymphomas, were identified. In the CTCL group, 75% of the patients received an anti-TNF-α agent for a presumed inflammatory skin condition. Mycosis fungoides and Sézary syndrome were the most common subtypes of CTCL diagnosed. Advanced disease (stage IIB to IVA) was commonly seen at time of diagnosis and required aggressive therapy, including stem cell transplant in 3 patients; 2 patients in whom cutaneous B-cell lymphomas was diagnosed had an indolent course. A total of 31 cases were gathered from a literature search. LIMITATIONS: This is a retrospective study. CONCLUSIONS: Our findings suggest that the disease of most of the identified patients was misdiagnosed as psoriasis or eczema; therefore, a comprehensive morphologic and molecular review of skin biopsy specimens and peripheral blood samples should be considered before initiation of anti-TNF-α therapy in patients with poorly defined dermatitis or atypical presentations of psoriasis.

Clinical manifestations and pathogenesis of cutaneous lymphomas: current status and future directions.

The primary cutaneous lymphomas are a heterogeneous group of T-, Natural Killer- and B- cell neoplasms with a wide range of clinical and pathological presentations, and with very different prognoses compared to systemic lymphomas. Recent studies have shown that the skin microenvironment, which is composed of various immune cell subsets as well as their spatial distribution and T-cell interactions through different chemokines and cytokines, has an important role in the development and pathogenesis of cutaneous lymphomas and has assisted in the development of novel and more effective immunotherapies. The following review will focus on the major subtypes of primary cutaneous lymphomas, including the clinical and histological patterns, molecular hallmarks, and current and future treatment strategies.