Results of an open-label multicenter phase 2 trial of lenalidomide monotherapy in refractory mycosis fungoides and Sézary syndrome

Unveiling the Role of the Cellular Tumor Microenvironment and the Therapeutic Targets it Provides in Cutaneous T-Cell Lymphoma

PURPOSE OF REVIEW

Cutaneous T-Cell Lymphoma (CTCL) poses challenges both in diagnosis and prognosis. The purpose of this review is to address the role of profiling immune and non-immune cells in the tumor microenvironment (TME) as it provides information for better diagnosis, prognosis, biomarker discovery, and personalized treatment strategies.

RECENT FINDINGS

Recent evidence suggests that the progression of CTCL is closely linked to the Tumor Microenvironment (TME) which comprises various cell types including immune cells, stromal cells, blood vessels, and the extracellular matrix. Cell profiling within the TME demonstrates the perplexity of intracellular communication of the different cell fates and their mediators as the disease progresses. CTCL as a rare form of non-Hodgkin lymphoma often misdiagnosed due to its similarity to other skin conditions. It encompasses diseases like Mycosis fungoides (MF) and Sézary Syndrome (SS), with the latter being more severe. Advances in studying the TME have shown its pivotal role in CTCL progression, highlighting the need for comprehensive cell profiling to enhance diagnosis, prognosis, and treatment personalization.

Management of Mycosis Fungoides and Sézary Syndrome With Oral Systemic Therapies

Mycosis fungoides (MF) and Sézary syndrome (SS) are subtypes of cutaneous T-cell lymphoma with numerous topical and systemic therapies. Early-stage MF can be managed with topical corticosteroids, mechlorethamine, and phototherapy. However, patients are often non-responsive to topical therapies, thus requiring systemic therapies. There are few studies summarizing oral (PO) therapies for MF and SS. We aim to discuss the efficacy and safety of FDA-approved, off-label, and investigational oral therapies for MF and SS. FDA-approved oral therapies include bexarotene and vorinostat, both of which are effective in patients who are recalcitrant to prior topical therapies. Off-label oral therapies include methotrexate, acitretin, and chlorambucil. Methotrexate improves MF lesions in both early-stage and late-stage MF and is effective in erythrodermic MF. A combination of acitretin with phototherapy may lead to better response rates compared to acitretin monotherapy. Chlorambucil is mainly used to treat erythrodermic MF. Investigational oral therapies for MF include tenalisib, duvelisib, cerdulatinib, lenalidomide, bortezomib, and azacytidine, and direct comparison studies between these investigational agents and FDA-approved therapies should be undertaken to better understand their role in the management of MF and SS.

What's New in Cutaneous T-Cell Lymphoma-Associated Pruritus

Cutaneous T-cell lymphomas are a heterogenous group of lymphomas that cause various skin manifestations. Severe pruritus occurs frequently in cutaneous T-cell lymphoma and negatively impacts patients' quality of life. The pathophysiology of cutaneous T-cell lymphoma-associated itch is complex and involves various immune cells, inflammatory cytokines, and neuroimmune interactions. Treating cutaneous T-cell lymphoma pruritus can be challenging, and there have been few randomized controlled studies evaluating the use of antipruritic treatments in these patients. Systemic therapies targeting the disease have also been shown to have some antipruritic effects. Furthermore, although biologic therapy has revolutionized the treatment of other pruritic skin conditions, the use of biologics in cutaneous T-cell lymphoma remains controversial.

Advances in Immunotherapy for the Treatment of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphoma (CTCL) is a heterogenous disease that consists of distinct clinicopathologic entities and presentations requiring a unique and expert approach to management. The most common subtype is mycosis fungoides, in which local disease has an excellent prognosis and is often managed with topical therapy alone. More extensive cutaneous involvement as well as involvement of lymph nodes and the peripheral blood (Sezary syndrome) require systemic therapies. Recent years have brought an expansion of therapeutic options, specifically with immune-based approaches that were developed using the knowledge gained regarding the biology and molecular pathology of CTCL. Previous systemic therapies such as retinoids, histone deacetylase inhibitors, and chemotherapeutic agents come with significant toxicity and only short-term response. Newer agents such as mogamulizumab and brentuximab vedotin use a targeted immune-based approach leading to longer periods of response with less systemic toxicity. While still in its infancy, the use of immune checkpoint inhibitors such as nivolumab and pembrolizumab appears promising, and while their current clinical application is limited, early data suggest possible future areas for research of immune manipulation to treat CTCL. Herein, we review these novel immune-based treatment strategies, their superiority over prior systemic options, and the ongoing need for further research and clinical trial enrollment.

Treating relapsed/refractory mature T- and NK-cell neoplasms with tislelizumab: a multicenter open-label phase 2 study

Patients with relapsed/refractory (R/R) mature T- and natural killer (NK)-cell neoplasms lack effective treatments after failure of standard therapies. This phase 2 study evaluated the efficacy and safety of the programmed cell death protein 1 inhibitor tislelizumab in these patients. Seventy-seven patients were treated with 200 mg tislelizumab every 3 weeks. Twenty-two patients with extranodal NK-/T-cell lymphomas were enrolled in cohort 1; 44 patients with peripheral T-cell lymphoma (PTCL) were enrolled in cohort 2 (21 patients had PTCL not otherwise specified, 11 patients had angioimmunoblastic T-cell lymphoma, and 12 patients had anaplastic large-cell lymphoma). Cohort 3 comprised 11 patients with cutaneous T-cell lymphoma, of which 8 patients had mycosis fungoides (MF) and 3 had Sézary syndrome. Of the 77 patients, 76.6% had advanced-stage disease, 51.9% had refractory disease, and 49.4% received ≥3 prior systemic regimens. Promising efficacy was observed in cohort 3 (median follow-up [FU], 16.6 months; overall response rate [ORR], 45.5%; complete response [CR], 9.1%; median duration of response [DOR], 11.3 months; median progression-free survival, 16.8 months; median overall survival, not reached). Modest efficacy was observed in cohort 1 (median FU, 8.4 months; ORR, 31.8%; CR, 18.2%; median DOR, not reached) and cohort 2 (median FU, 9.3 months; ORR, 20.5%; CR, 9.1%; median DOR, 8.2 months). Most treatment-related adverse events were grade 1 or 2, and the safety profile was consistent with the known safety profile of tislelizumab. In conclusion, tislelizumab was well tolerated, achieving modest efficacy in R/R mature T- and NK-cell neoplasms, with some long-lasting remissions. This trial was registered at www.clinicaltrials.gov as #NCT03493451.

CD25: A potential tumor therapeutic target

CD25 is the alpha-chain of the heterotrimer IL-2 receptor. CD25 is expressed on the surface of both immune and non-immune cells with different frequencies. For cancers, CD25 is expressed at high levels in many types of hematological malignancies, but at low levels in most solid tumors. CD25 is also highly expressed in activated circulating immune cells and regulatory T cells (Tregs). Infiltration of Tregs in the tumor microenvironment can lead to an imbalanced ratio of effector T cells (Teffs) and Tregs, which is associated with the progression of cancers. A rescued Teff/Treg cell ratio indicates an efficient anti-tumor response to immunotherapy. CD25 as a potential target for the depletion of Tregs is critical in developing new immunotherapeutic strategies. Few articles have summarized the relationships between CD25 and tumors, or the recent progress of drugs targeting CD25. In this paper, we will discuss the structures of IL-2 and IL-2R, the biological function of CD25 and its important role in tumor therapy. In addition, the latest research on drugs targeting CD25 has been summarized, providing guidance for future drug development.

Harnessing the immune system in the treatment of cutaneous T cell lymphomas

Cutaneous T cell lymphomas are a rare subset of non-Hodgkin's lymphomas with predilection for the skin with immunosuppressive effects that drive morbidity and mortality. We are now appreciating that suppression of the immune system is an important step in the progression of disease. It should come as no surprise that therapies historically and currently being used to treat these cancers have immune modulating functions that impact disease outcomes. By understanding the immune effects of our therapies, we may better develop new agents that target the immune system and improve combinatorial treatment strategies to limit morbidity and mortality of these cancers. The immune modulating effect of therapeutic drugs in use and under development for cutaneous T cell lymphomas will be reviewed.

Cutaneous T-cell lymphomas: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or the blood involvement are generally approached with systemic therapies, including biologic-response modifiers, histone deacetylase inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Retrospective Analysis of 118 Patients With Cutaneous T-Cell Lymphomas: A Single-Center Experience

Cutaneous T-cell lymphomas (CTCL) represent rare non-Hodgkin lymphomas (NHL) with an incidence less than 1 per 100,000 inhabitants. The most common type of CTCL is mycosis fungoides (MF), which represents approximately 60% of all CTCL, followed by Sézary syndrome (SS), approximately 5%. We retrospectively analyzed the outcome of 118 patients with MF (n=96) and SS (n=22) treated between the years 1998 and 2021 at the Charles University General Hospital in Prague, Czech Republic. The ratio between men and women was 1.2:1 (62 men, and 56 women). The median age at diagnosis was 62 years (23 to 92 years). From the MF cohort 48 patients (50% out of MF cohort) presented with advanced stage disease. Ninety patients (77%) received a systemic treatment at any time from the diagnosis; the median number of therapy lines was two. At the time of database lock, the overall survival (OS) of 96 patients with MF reached 17.7 years with the median follow-up 4.0 years. With the median follow-up 2.6 years, the median OS of 22 patients with SS was 3.5 years. The most common type of systemic therapy for MF included low-dose methotrexate (61%), interferon-alpha (58%), bexarotene (28%), and chlorambucil (25%). The most common type of therapy for SS included bexarotene (64%), extracorporeal photopheresis (50%), and interferon-alpha (45%). Only the minority of patients received innovative targeted agents including brentuximab vedotin, mogamulizumab, or pembrolizumab. Besides the retrospective analysis of the CTCL cohort, current standards and future perspectives of selected innovative agents are summarized and discussed. The analyzed cohort represents the largest cohort of CTCL patients in the Czech Republic. Overall, the survival parameters of our CTCL cohort are comparable to those previously published by other groups. In conclusion, our analysis of 118 real world cohort of consecutive CTCL patients treated at the single center confirmed the efficacy of immune response modifiers and underlines the urgent need for ample implementation of innovative agents and their combinations into earlier lines of therapy.

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 manifests 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 heterogenous 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.

What factors guide treatment selection in mycosis fungoides and Sezary syndrome?

Cutaneous T-cell lymphoma (CTCL) comprises a spectrum of T-cell lymphomas with primary skin involvement. Mycosis fungoides (MF) and Sezary syndrome (SS) are the common subtypes of CTCL in which patients present with widely diverse profiles of skin involvement and varying extents of extracutaneous disease. Patients with early-stage disease have an excellent prognosis and are managed primarily with skin-directed therapies; however, those with advanced-stage MF or SS often require multiple lines and recurrent courses of systemic therapies. Many options are available when considering systemic agents, and it is often challenging to know how to prioritize therapies to address a patient's objective disease and quality of life issues. Appreciating the disease heterogeneity and understanding the patient's overall disease profile (eg, skin, lymph nodes, blood, large cell transformation) serve as a useful framework in aligning therapies that can optimally treat active sites of disease. Tissue or blood biomarkers can be integrated into our process of prioritizing therapies and personalizing management in MF or SS. Multidisciplinary management and optimizing supportive care are additional key elements for a favorable outcome. Appropriate patients with high-risk disease should be considered for allogeneic hematopoietic stem cell transplant.

Role of lenalidomide in the treatment of peripheral T-cell non-Hodgkin lymphomas

T-cell lymphomas (TCLs) represent a group of lymphoid neoplasms characterized by an aggressive clinical course, even after an anthracycline-containing regimen. Novel agents for patients with relapsed/refractory TCL are urgently needed. Lenalidomide is an oral drug with immunomodulatory, antiangiogenic and direct antineoplastic effects. These peculiar mechanisms of action make TCL an attractive target for lenalidomide. We have identified five clinical trials in which lenalidomide monotherapy was investigated to treat TCL, including cutaneous TCL (CTCL) and adult T-cell lymphoma/leukemia (ATLL). In the ATLL-002 study, the overall response rate (ORR) was 42% and median progression-free survival (PFS) and overall survival were 3.8 mo and 20.3 mo, respectively. In a phase II trial for CTCL, ORR was 28% and median PFS and overall survival were 8 mo and 43 mo, respectively. For nodal peripheral TCL, ORR was between 10% and 43% in three clinical trials, with a median PFS of about 4 mo, even if some patients had a durable response. Overall toxicity is manageable and grade 3-4 events are mainly hematological and reversible. Combination strategies did not improve PFS. In conclusion, lenalidomide could represent a suitable treatment option for relapsed/refractory TCL, especially for neoplasms with a T-follicular helper origin, such as angioimmunoblastic TCL.

The Microenvironment's Role in Mycosis Fungoides and Sézary Syndrome: From Progression to Therapeutic Implications

BACKGROUND

Mycosis fungoides (MF) and Sezary Syndrome (SS) are the most common cutaneous T-cell lymphomas. It has been hypothesized that the interaction between the immune system, cutaneous cells, and neoplastic elements may play a role in MF/SS pathogenesis and progression.

METHODS

This paper aims to revise in a narrative way our current knowledge of the microenvironment's role in MF/SS.

RESULTS AND CONCLUSIONS

Literature data support a possible implication of microenvironment cells in MF/SS pathogenesis and progression, opening up new therapeutic avenues.

Cutaneous T-cell lymphomas: 2021 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with systemic therapies, including biologic-response modifiers, histone deacetylase inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Romidepsin and lenalidomide-based regimens have efficacy in relapsed/refractory lymphoma: Combined analysis of two phase I studies with expansion cohorts

Romidepsin (histone deacetylase inhibitor), lenalidomide (immunomodulatory agent), and carfilzomib (proteasome inhibitor), have efficacy and lack cumulative toxicity in relapsed/refractory lymphoma. We performed two investigator initiated sequential phase I studies to evaluate the maximum tolerated dose (MTD) of romidepsin and lenalidomide (regimen A) and romidepsin, lenalidomide, and carfilzomib (regimen B) in relapsed/refractory lymphoma. Cohorts in T-cell lymphoma (TCL), B-cell lymphoma (BCL) were enrolled at the MTD. Forty-nine patients were treated in study A (27 TCL, 17 BCL, 5 Hodgkin lymphoma (HL)) and 27 (16 TCL, 11 BCL) in study B. The MTD of regimen A was romidepsin 14 mg/m² IV on days 1, 8, and 15 and lenalidomide 25 mg oral on days 1-21 of a 28-day cycle. The MTD of regimen B was romidepsin 8 mg/m² on days 1 and 8, lenalidomide 10 mg oral on days 1-14 and carfilzomib 36 mg/m² IV on days 1 and 8 of a 21-day cycle. In study A, 94% had AEs ≥Grade 3, most commonly neutropenia (49%), thrombocytopenia (53%), and electrolyte abnormalities (49%). In study B 59% had AEs ≥Grade 3, including thrombocytopenia (30%) and neutropenia (26%). In study A the ORR was 49% (50% TCL, 47% BCL, 50% HL). In study B the ORR was 48% (50% TCL, 50% BCL). For study A and B the median progression free survival (PFS) was 5.7 months and 3.4 months respectively with 11 patients proceeding to allogeneic transplant. The combinations of romidepsin and lenalidomide and of romidepsin, lenalidomide and carfilzomib showed activity in relapsed/refractory lymphoma with an acceptable safety profile.

Immune Check Point Inhibitors in Primary Cutaneous T-Cell Lymphomas: Biologic Rationale, Clinical Results and Future Perspectives

Primary cutaneous T-cell lymphomas (PCTCL) are the most common types of cutaneous lymphomas, with Mycosis fungoides as the most frequent subtype. Besides early stages which usually have a good prognosis, advanced stages remain a great therapeutic challenge with low survival rates. To date, none of the currently available therapeutic options have significantly improved the outcomes of advanced cutaneous lymphomas. Recent studies have demonstrated that immune-checkpoint molecules, such as PD-1 and CTLA-4, play part in the proliferation pathways of neoplastic T-cells, as well as in other tumors. Hence, the potential role of immune-checkpoint-inhibitors in treating cutaneous lymphomas has been investigated in the last years. Herein, we outline the current knowledge regarding the role of immune-checkpoint molecules in PCTCL, their signaling pathways, microenvironment and therapeutic inhibition rationale. Moreover, we review the published data on immunotherapies in PCTCL and summarize the currently ongoing clinical trials in this field.

Mycosis Fungoides in Children and Adolescents: A Systematic Review

Importance

Comprehensive data on childhood mycosis fungoides (MF) is scarce.

Objective

To describe clinical features, immunophenotypes, various treatment options, and prognosis of MF in children and adolescents.

Evidence Review

This systematic review searched MEDLINE via PubMed, Embase, Cochrane, and Scopus databases in October 2019. The search terms included mycosis fungoides, infant, children, and adolescent. No filter for the publication period was used, but studies written in a language other than English were excluded. Reference lists of the relevant articles were also searched manually. Case series and case reports were included if data on childhood MF were extractable. The Asan Medical Center database for cases of childhood MF was also searched. Patients were treated from January 1, 1990, to July 31, 2019, and were younger than 20 years at the time of diagnosis. The methodologic quality of the included studies was assessed with items from the Newcastle-Ottawa scale. Data were analyzed from December 9, 2019, to September 4, 2020.

Findings

A total of 571 unique patients were included. The mean (SD) age at diagnosis was 12.2 (4.2) years; at onset, 8.6 (4.2) years. The female-to-male ratio was 1:1.6 (350 male patients [61.3%]). Among 522 patients with data available at diagnosis, stage 1 disease constituted 478 cases (91.6%), followed by stage 2 (39 [7.5%]) and stage 4 (5 [1.0%]). Among the 567 patients with data available, the most common variant of MF was the hypopigmented form (309 [54.5%]), followed by classic MF (187 [33.0%]). The MF lesions were predominantly the CD4+ and CD8+ immunophenotype in 99 (49.5%) and 79 (39.5%) of 200 patients, respectively. Among the treatments, narrowband UV-B was the most frequently used (150 of 426 [35.2%]). Most patients were alive with the disease (185 of 279 [66.3%]); 83 of 279 (29.8%) were in complete remission; and 11 of 279 (3.9%) had died by the last follow-up. A longer time from onset to diagnosis (hazard ratio [HR], 1.24; 95% CI, 1.06-1.45), granulomatous slack skin (HR, 12.25; 95% CI, 1.99-75.26), granulomatous MF (HR, 14.59; 95% CI, 1.31-162.00), a history of organ transplant (HR, 10.15; 95% CI, 0.98-105.37), and stage 2 disease at the time of diagnosis (HR, 10.22; 95% CI, 2.94-35.50) were associated with worse outcomes.

Conclusions and Relevance

The findings of this review suggest that there is often a significant delay until the establishment of a correct diagnosis of childhood MF, which may be detrimental to the prognosis.

Cancer therapies based on targeted protein degradation - lessons learned with lenalidomide

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of 'degrader' drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies.

How we treat advanced stage cutaneous T-cell lymphoma - mycosis fungoides and Sézary syndrome

T-cell lymphomas (TCLs) constitute a rare subset of non-Hodgkin lymphomas, with mycosis fungoides/Sézary syndrome (MF/SS) being the most common subtype of cutaneous TCLs (CTCLs). Considered an incurable but treatable disease, MF/SS management presents several challenges including diagnostic delays, debilitating effect on patients' quality of life, need for several lines of therapies, multidisciplinary care and cumulative drug toxicities limiting duration of use. The present review intends to provide an overview of the recent advances in our understanding of the biology of CTCL and how these are being leveraged to provide additional treatment options for management of advanced and recurrent disease. In addition, the discussion of the different modalities of treatment is summarised to further outline the importance of multidisciplinary care and early referral to CTCL centres.

Cell signaling in cutaneous T-cell lymphoma microenvironment: promising targets for molecular-specific treatment

Cutaneous T-cell lymphomas (CTCL) result from the infiltration and proliferation of a population of T cells in the skin, inducing changes in the activity of both T cells and surrounding skin cells. In the CTCL microenvironment, cell interactions mediated by cell signaling pathways are altered. Defining changes in cell signaling enables to understand T-cell deregulations in the CTCL microenvironment and thus the progression of the disease. Moreover, characterizing signaling networks activated in CTCL stages can lead to consider new molecular biomarkers and therapeutic targets. Focusing on mycosis fungoides (MF), the most frequent variant of CTCL, and Sézary syndrome (SS), its leukemic variant, this review highlights recent molecular and genetic findings revealing modifications of key signaling pathways involved in (1) cell proliferation, cell growth, and cell survival such as MAP kinases and PI3K/Akt; (2) immune responses derived from TCR, TLR, JAK/STAT, and NF-kB; and (3) changes in tissue conditions such as extracellular matrix remodeling, hypoxia, and angiogenesis. Alterations in these signaling networks promote malignant T-cell proliferation and survival, T-cell migration, inflammation, and suppression of immune regulation of malignant T cells, making a skin microenvironment that allows disease progression. Targeting key proteins of these signaling pathways, using molecules already available and used in research, in clinical trials, and with other disease indications, can open the way to different therapeutic options in CTCL treatment.

Novel therapies targeting cutaneous T cell lymphomas and their microenvironment

Cutaneous T-cell lymphomas (CTCL) are rare non-Hodgkin lymphomas with a generally indolent course managed with topical, skin-directed therapies. A small subset, however, will progress to advanced stage disease necessitating systemic therapy for disease control. Currently approved therapies have low response rates and generally short durations of response. Novel therapies, therefore, are urgently needed to address this unmet need. In this review, the mechanisms of CTCL pathogenesis and progression, including the role of the tumor microenvironment and molecular alterations, are summarized. Based on these biologic insights, novel therapies currently under investigation and those with a strong preclinical biologic rationale including T cell and macrophage checkpoint inhibitors, epigenetic regulators, targeted antibodies, tyrosine kinase inhibitors, and apoptosis modulating therapies are discussed.

Mycosis fungoides and Sézary syndrome: Australian clinical practice statement

Primary cutaneous lymphomas represent a heterogeneous group of T- and B-cell lymphomas with distinct clinical presentations, histopathologic features, treatment approaches and outcomes. The cutaneous T-cell lymphomas, which include mycosis fungoides and Sézary syndrome, account for the majority of the cutaneous lymphomas. This Clinical Practice Statement is reflective of the current clinical practice in Australia. An expanded form of the Clinical Practice Statement (and updates), along with helpful patient resources and access to support groups, can be found at the following (http://www.australasianlymphomaalliance.org.au).

The changing therapeutic landscape, burden of disease, and unmet needs in patients with cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) have a chronic, relapsing course, and the most common subtypes are mycosis fungoides and Sézary syndrome. The disease causes visible skin alterations and can also cause alopecia, pruritus and pain, all of which can impact patients' health-related quality of life (HRQoL). The goal of treatment is to reduce symptoms and prevent disease progression. However, treatment recommendations are often based on low levels of evidence due to the lack of well-designed randomised clinical trials and treatment guidelines, and approved drugs vary considerably across different countries and regions. Currently, available treatments rarely lead to durable remissions and eventually become less effective, meaning patients often require multiple therapy changes. Skin-directed therapies (SDTs) are first-line treatments for early-stage CTCL, whereas systemic therapies may be needed for early-stage disease that does not respond to SDT or for advanced-stage disease. However, patients can experience significant side-effects with these treatments or may be unable to tolerate them. Hence, there is an unmet need for effective therapies with good safety profiles for the treatment of early- and late-stage CTCL. Here, we review current treatment guidelines, investigational and approved treatments, the impact of CTCL on patients' HRQoL, and the treatment of pruritus.

IMiDs New and Old

PURPOSE OF REVIEW

IMiDs are a class of biologic agents with immunomodulatory, anti-angiogenic, and direct anti-cancer activities. This review summarizes current data on clinical development and application of IMiDs in non-Hodgkin lymphoma (NHL) subtypes, focusing primarily on lenalidomide, with additional discussion on managing common side effects.

RECENT FINDINGS

Improved upon the prototype thalidomide, the second-generation compound lenalidomide has enhanced immunological and anti-cancer properties with fewer side effects, while next-generation small molecule cereblon/E3 ubiquitin ligase modulator CC-122 is in early clinical studies. Lenalidomide is FDA-approved for treatment of relapsed/refractory mantle cell lymphoma as a single agent, as well as in combination with rituximab for R/R follicular lymphoma and marginal zone lymphoma. In addition, numerous clinical trials of lenalidomide, as single agent, in combination with anti-CD20 antibodies, or in combination with chemoimmunotherapy regimens, have shown promise in aggressive and indolent NHL in both the upfront and relapsed/refractory setting. As clinical trials with lenalidomide continue to find success in both indolent and aggressive lymphomas, IMiDs are poised to be important building blocks for combinatorial strategies with antibodies, chemotherapy, novel target agents, and emerging immunotherapy involving immune checkpoint inhibitors and chimeric antigen receptor T cell (CAR-T) therapy. Delineation of treatment-specific and disease-specific biomarkers is an important research objective to gain insight into potential mechanisms of action, and to guide future clinical development.

Mycosis fungoides: developments in incidence, treatment and survival

BACKGROUND

Prior studies have demonstrated improved disease-specific survival of mycosis fungoides (MF) patients over the last 50 years.

OBJECTIVE

To analyse patterns of survival and incidence from 1973 to 2016 and determine whether apparent improvements in MF-specific survival are due to lead-time bias rather than improvements in treatment.

METHODS

We performed an analysis of 10 155 patients diagnosed with MF from 1973 to 2016 in the United States cancer registries of SEER-18. We also performed a literature review of papers including stage data for unselected populations of MF patients prior to 2000.

RESULTS

Incidence of MF increased from 3.0 per million person-years in the 1970s to 5.9 in the 2010s. For all cohorts, non-Hodgkin lymphoma (including MF) was the leading cause of death. Survival analysis demonstrated marked improvement in disease-specific and overall survival from the 1970s to 2010s. Based on systematic review of the literature, 32%-73% of patients diagnosed prior to 2000 were diagnosed with early-stage disease, as opposed to 81% of patients in the SEER 2000-2016 cohort (P < 0.035 for all cohorts).

CONCLUSIONS

Although there have been improvements in MF-related survival over the last 50 years, these may reflect improvements in our ability to diagnose early-stage disease rather than improved treatment.

[Cutaneous lymphomas : Clinical presentation - diagnosis - treatment]

Cutaneous lymphomas comprise different subgroups with distinct biological behavior. Mycosis fungoides, the most common cutaneous lymphoma, presents with patches, plaques, tumors and erythroderma. Therapeutic options depend on stage and comprise local skin-directed treatment in early stages, while later stages and Sézary syndrome require systemic therapies including bexarotene, interferon or brentuximab vedotin. While the rare CD4-positive lymphoproliferation and acral CD8-positive lymphoma present with an invariably indolent course, cutaneous peripheral T‑cell lymphomas exhibit an aggressive clinical behavior. Among the subgroup of cutaneous B‑cell lymphomas, primary cutaneous marginal zone lymphoma and follicle center cell lymphoma belong to indolent entities with almost unrestricted overall survival, whereas cutaneous large B‑cell lymphoma presents with a significant risk of systemic dissemination and is associated with high lethality.

[Cutaneous lymphomas : Clinical presentation - diagnosis - treatment]

Cutaneous lymphomas comprise different subgroups with distinct biological behavior. Mycosis fungoides, the most common cutaneous lymphoma, presents with patches, plaques, tumors and erythroderma. Therapeutic options depend on stage and comprise local skin-directed treatment in early stages, while later stages and Sézary syndrome require systemic therapies including bexarotene, interferon or brentuximab vedotin. While the rare CD4-positive lymphoproliferation and acral CD8-positive lymphoma present with an invariably indolent course, cutaneous peripheral T‑cell lymphomas exhibit an aggressive clinical behavior. Among the subgroup of cutaneous B‑cell lymphomas, primary cutaneous marginal zone lymphoma and follicle center cell lymphoma belong to indolent entities with almost unrestricted overall survival, whereas cutaneous large B‑cell lymphoma presents with a significant risk of systemic dissemination and is associated with high lethality.

Mycosis fungoides and Sézary syndrome: 2019 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas (CTCL) are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis fungoides (MF) or Sézary syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, skin-directed therapies are preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with systemic therapies. These include biologic-response modifiers, histone deacetylase (HDAC) inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Novel and Future Therapeutic Drugs for Advanced Mycosis Fungoides and Sézary Syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphoma. The majority of MF cases present with only patches and plaques and the lesions are usually limited to the skin. On the other hand, in some cases, patients show skin tumors or erythroderma followed by lymph node involvement and rarely visceral organ involvement. SS is a rare, aggressive cutaneous T-cell lymphoma marked by exfoliative erythroderma, lymphadenopathy, and leukemic blood involvement. Because patients with relapsed or refractory MF/SS display a poor prognosis and the current treatment options are characterized by high rates of relapse, there is unmet need for the efficient treatment. This review provides a discussion of the recent and future promising therapeutic approaches in the management of advanced MF/SS. These include mogamulizumab, brentuximab vedotin, alemtuzumab, immune checkpoint inhibitors, IPH4102 (anti-KIR3DL2 antibody), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat, belinostat, and resminostat), pralatrexate, forodesine, denileukin diftitox, duvelisib, lenalidomide, and everolimus.

Mogamulizumab: a new tool for management of cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) poses unique treatment challenges, given its range of presentations and numerous systemic therapy options. These options often lack comparative evidence or are characterized by low response rates and short remission duration in relapsed/refractory disease. The approval of mogamulizumab, a humanized, glycoengineered IgG1κ monoclonal antibody targeting the chemokine receptor type 4 (CCR4) chemokine receptor, brings a novel tool into the spectrum of treatment options for advanced CTCL and adult T-cell leukemia/lymphoma (ATLL). CCR4 is expressed in almost all cases of ATLL, and in a majority of CTCLs, particularly when blood involvement is present. In a Phase III randomized trial, mogamulizumab was associated with 28% overall response rate among patients with relapsed CTCL, median progression-free survival of 7.7 months, and median duration of remission of 14.1 months. Responses are more frequent among patients with Sézary syndrome and within the blood compartment. Common adverse effects include rash and infusion reactions, which are usually low grade. Sentinel reports indicate that exposure to mogamulizumab may result in severe or refractory graft vs host disease after allogeneic bone marrow transplantation, highlighting the need for vigilance and expert management. Further research may establish incremental efficacy of combining mogamulizumab with cytotoxic or immunomodulatory agents in CTCL, ATLL, and possibly other lymphomas and even solid tumors.

A case of AITL complicated by EBV-positive B cell and monoclonal plasma cell proliferation and effectively treated with lenalidomide

Angioimmunoblastic T-cell lymphoma (AITL) is a common subtype of peripheral T-cell lymphoma with an aggressive clinical course and poor prognosis after conventional chemotherapy, for which there is no current standard of care. We describe here an 87-year-old woman with AITL, whose clinical diagnosis was complicated by the presence of B immunoblasts positive for Epstein-Barr virus in the lymph nodes and monoclonal plasma cells in the bone marrow at initial presentation. Rebiopsy of the lymph node led to the correct diagnosis of AITL with concurrent smoldering plasma cell myeloma. She was treated with several courses of conventional chemotherapy, resulting in progressive disease, and then switched to the immunomodulatory drug lenalidomide, which used in Japan for the treatment of multiple myeloma. Lenalidomide was effective in controlling both AITL and plasma cell myeloma.

Immunologic Milieu of Mature T-Cell and NK-Cell Lymphomas-Implications for Therapy

PURPOSE OF THE REVIEW

T-cells and natural killer (NK) cells share the same ontogeny, and lymphomas derived from them are clinically diverse, occurring in nodal and extranodal sites. In addition to inherent properties of these lymphomas, their microenvironment also impacts on pathogenesis and response to therapy. An understanding of the milieu of T-cell and NK cell lymphomas has important implications on treatment.

RECENT FINDINGS

Components of the microenvironment include tumour-associated macrophages (TAM), non-neoplastic T-cells and B-cells, eosinophils, dendritic cells, endothelial cells and blood vessels. TAM typically undergoes M2 polarization, promoting angiogenesis and inhibiting anti-tumour cellular immunity. In lymphomas of follicular helper T-cell derivation, increased B-cell proliferation occurs, which may in turn enhance neoplastic T-cell growth. The expression of immune checkpoint ligands on TAM, dendritic cells or lymphoma cells induces an immunosuppressive environment conducive to neoplastic proliferation. Strategies against this complex cellular and immunologic microenvironment have shown promises. These include the use of signal transduction inhibitors, monoclonal antibodies against chemokines or non-neoplastic microenvironmental cells, immunomodulatory drugs and immune checkpoint blockade. As T-cell and NK cell lymphomas are highly heterogeneous, clinical trials to demonstrate efficacy of a given therapeutic approach requires careful design aiming at enriching patient populations who will best respond. Targeting of the immunologic milieu in T-cell and NK-cell lymphomas offers exciting challenges and opportunities.

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.

Integrating novel systemic therapies for the treatment of mycosis fungoides and Sézary syndrome

Novel systemic therapies are generally prescribed to patients with advanced-stage disease or those with early-stage disease refractory to skin-directed therapies. In general, systemic chemotherapy should be reserved for patients who fail to respond to biological agents. Such biological agents include interferon alfa, bexarotene, histone deacetylase inhibitors (vorinostat, romidepsin), brentuximab vedotin and mogamulizumab. Extracorporeal photopheresis is particularly effective for patients with Sézary Syndrome. Allogeneic transplantation is becoming increasing used for younger patients. Novel agents in advanced development include the monoclonal antibody IPH4102,duvelisib,and the new modified formulation of denileukin diftitox. The choice of agents for patients is typically a balance of patient factors (age, co-morbidities, geographic location), relative efficacy and toxicity.

New Therapies and Immunological Findings in Cutaneous T-Cell Lymphoma

Primary cutaneous lymphomas comprise a group of lymphatic malignancies that occur primarily in the skin. They represent the second most common form of extranodal non-Hodgkin’s lymphoma and are characterized by heterogeneous clinical, histological, immunological, and molecular features. The most common type is mycosis fungoides and its leukemic variant, Sézary syndrome. Both diseases are considered T-helper cell type 2 (Th2) diseases. Not only the tumor cells but also the tumor microenvironment can promote Th2 differentiation, which is beneficial for the tumor cells because a Th1 environment enhances antitumor immune responses. This Th2-dominant milieu also underlies the infectious susceptibility of the patients. Many components, such as tumor-associated macrophages, cancer-associated fibroblasts, and dendritic cells, as well as humoral factors, such as chemokines and cytokines, establish the tumor microenvironment and can modify tumor cell migration and proliferation. Multiagent chemotherapy often induces immunosuppression, resulting in an increased risk of serious infection and poor tolerance. Therefore, overtreatment should be avoided for these types of lymphomas. Interferons have been shown to increase the time to next treatment to a greater degree than has chemotherapy. The pathogenesis and prognosis of cutaneous T-cell lymphoma (CTCL) differ markedly among the subtypes. In some aggressive subtypes of CTCLs, such as primary cutaneous gamma/delta T-cell lymphoma and primary cutaneous CD8⁺ aggressive epidermotropic cytotoxic T-cell lymphoma, hematopoietic stem cell transplantation should be considered, whereas overtreatment should be avoided with other, favorable subtypes. Therefore, a solid understanding of the pathogenesis and immunological background of cutaneous lymphoma is required to better treat patients who are inflicted with this disease. This review summarizes the current knowledge in the field to attempt to achieve this objective.

Systemic Treatment Options for Advanced-Stage Mycosis Fungoides and Sézary Syndrome

PURPOSE OF REVIEW

Cutaneous T-cell lymphoma (CTCL) is a rare form of non-Hodgkin lymphoma. Globally, the most common subtypes of CTCL are mycosis fungoides and Sézary syndrome. CTCL can confer significant morbidity and even mortality in advanced disease. Here we review the current and potential future treatments for advanced-stage CTCL.

RECENT FINDINGS

Heterogeneity of treatment choice has been demonstrated both in US and non-US centers. Systemic treatment choice is currently guided by prognostic features, incorporating stage, immunophenotypic and molecular findings, and patient-specific factors such as age and comorbidities. Randomized controlled studies are uncommon, and the literature is composed predominantly of retrospective, cohort, and early-phase studies. International consensus guidelines are available; however, the lack of comparative trials means that there is no clear algorithmic approach to treatment. This review article reports on the systemic treatment options in current use for advanced CTCL, and on the possible future therapies, acknowledging that an algorithmic approach is not yet forthcoming to guide treatment prioritization.

Venous thromboembolism in patients with non-Hodgkin lymphoma or chronic lymphocytic leukemia treated with lenalidomide: a systematic review

Lenalidomide has been associated with an increased risk of venous thromboembolism (VTE) in multiple myeloma. It is unclear whether patients with non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) are also at such risk. We conducted a systematic review of the incidence of VTE in prospective trials of lenalidomide-treated patients with NHL or CLL. Sixty-eight unique reports were assessed for inclusion. For grade ≥3 VTE, 98 events were reported in 3043 patients (60 studies) (crude incidence: 3.22% [95% confidence interval: 2.6-3.9%]). For any grade VTE, 97 events were reported in 2244 patients (46 studies) (crude incidence: 4.32% [3.5-5.2%]). Subgroup analysis showed no difference based on histological subtype or use of prophylaxis. The study is at risk of bias, largely due to insufficient data from the individual studies. Within the limitations of this systematic review, we found a low risk of VTE in patients with NHL treated with lenalidomide.

Current systemic therapeutic options for advanced mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common cutaneous T-cell lymphomas (CTCLs). Both lack curative options, and advanced-stage carries a poor prognosis. Whilst there are a number of treatments available, achieving and maintaining a durable remission remains challenging. We review current systemic treatment options as monotherapy for advanced-stage MF (IIB-IV), appraising their mechanism of action, analyzing their efficacy, and describing toxicities. Individually, reported overall response rates (ORR) vary widely in the literature and duration of responses are typically short, ranging from 7.5 to 22.4 months. Combined therapy is frequently used in an effort to boost responses, although prospective studies comparing combinations to single agent therapies are rarely conducted. While recent translational research has led to increased understanding of the immunopathogenesis of MF and SS and the development of new treatments, current standard of care therapies are not curative and have low ORR for advanced-stage disease.

Cutaneous T-cell lymphomas: Focusing on novel agents in relapsed and refractory disease

Patients with relapsed or refractory cutaneous T-cell lymphoma (CTCL) display a dismal prognosis and their therapy represents an unmet medical need, as the best treatment strategy is yet to be determined. Exciting data on novel targeted agents are now emerging from recently concluded and ongoing clinical trials in patients with relapsed and refractory CTCL. Three FDA approved compounds are used as single agents including the oral retinoid bexarotene and histone deacetylase inhibitors romidepsin and vorinostat. Brentuximab vedotin, an anti-CD30 drug-conjugated monoclonal antibody, has received from European Commission the orphan designation but has not been approved by EMA yet. Several other molecules have demonstrated their activity in the same context and combination strategies are being explored. Participation in a well designed clinical trial is encouraged, as the introduction of novel agents will continue to expand the therapeutics options available in the management of CTCL.