Mogamulizumab Treatment Prior to Allogeneic Hematopoietic Stem Cell Transplantation Induces Severe Acute Graft-versus-Host Disease

Allogeneic hematopoietic stem cell transplantation after mogamulizumab in T-cell lymphoma patients: a retrospective analysis

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important therapy for patients with T-cell lymphomas, including cutaneous T-cell lymphoma (CTCL), adult T-cell lymphoma (ATL), and peripheral T-cell lymphoma (PTCL). Mogamulizumab is an anti-CCR4 antibody that has been associated with an increased risk of transplant-related complications in retrospective analyses of ATL, particularly when administered within 50 days before transplantation. This post hoc analysis of 3 clinical trials examined safety and outcome data for 32 patients with CTCL (n = 23), ATL (n = 7), or PTCL (n = 2) who underwent allo-HSCT after mogamulizumab treatment. Overall, 22 patients (69%) were known to have graft-versus-host disease (GVHD), 8 patients (25%) did not report GVHD, and 2 patients (6%) had unknown GVHD status. Fourteen patients with known GVHD underwent transplantation between 50 and 365 days after their last dose of mogamulizumab, while 2 underwent transplantation within 50 days after treatment. Based on this limited evidence, GVHD was not associated with the time interval from last mogamulizumab dose to transplantation.

Stem cell therapy for HTLV-1 induced adult T-cell leukemia/lymphoma (ATLL): A comprehensive review

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive form of cancer associated with human T-cell lymphotropic virus type 1 (HTLV-1) infection. The emerging field of stem cell therapies for ATLL is discussed, highlighting the potential of hematopoietic stem cell transplantation (HSCT) and genetically modified stem cells. HSCT aims to eradicate malignant T-cells and restore a functional immune system through the infusion of healthy donor stem cells. Genetically modified stem cells show promise in enhancing their ability to target and eliminate ATLL cells. The article presents insights from preclinical studies and limited clinical trials, emphasizing the need for further research to establish the safety, efficacy, and long-term outcomes of stem cell therapies for ATLL and challenges associated with these innovative approaches are also explored. Overall, stem cell therapies hold significant potential in revolutionizing ATLL treatment, and ongoing clinical trials aim to determine their benefits in larger patient populations.

Allogeneic stem cell transplant for treatment of mycosis fungoides and Sezary syndrome: a systematic review and meta-analysis

Allogeneic hematopoietic stem cell transplant (allo-HSCT) has been noted to be a potential curative treatment in cases of advanced-stage mycosis fungoides (MF) or Sezary syndrome (SS). To assess outcomes of allo-HSCT for MF/SS we performed a systematic review and meta-analysis including 15 manuscripts and 557 patients, published from 2010-2023. Meta-analysis revealed 1-year and 3+year overall survival (OS) of 51% (95% CI 39-64%) and 40% (32-49%). Progression-free survival at 1 year and 3+years were 42% (31-53%) and 33% (25-42%). Non-relapse mortality was 18% (13-23%). Relapse occurred in of 47% (40-53%) with a median time to relapse of 7.9 months (range 1.6-24 months). Rates of acute and chronic graft-versus-host disease (GVHD) were 45% (35-55%) and 40% (33-48%). Reduced-intensity conditioning (RIC) was associated with superior OS compared to myeloablative conditioning (MAC) (58% vs. 30%, p < 0.001). Of patients with relapse after allo-HSCT, 46% treated with donor lymphocyte infusion (DLI) achieved complete remission. These data support use of allo-HSCT for treatment of advanced-stage MF/SS and suggest superiority of RIC over MAC. Rates of GVHD were comparable to allo-HSCT in general. The improved OS for RIC and high rate of CR with DLI underscore the importance of the graft-versus-lymphoma effect in allo-HSCT for MF/SS.

Advances in the treatment of mycoses fungoides and Sézary syndrome: a narrative update in skin-directed therapies and immune-based treatments

Mycoses fungoides (MF) and Sézary syndrome (SS) are cutaneous T-cell lymphomas that are often challenging to manage given the absence of reliably curative therapies, at times high symptom burden with significant detriment to quality of life, and need for ongoing treatment for disease and symptom control. Recent developments in skin-directed treatments include optimizing the use of existing topical therapies, the introduction of known dermatological agents and treatment modalities for the specific treatment of MF/SS (such as mechlorethamine gel, calcineurin inhibitor creams, and photodynamic therapy), and novel local and topical agents. For advanced disease, dedicated clinical trials have translated to exciting progress, leading to the approval of brentuximab vedotin (2017) and mogamulizumab (2018) for relapsed MF/SS. Additional studies of other active systemic agents, including various cellular therapies, represent further attempts to add to the therapeutic armamentarium in treating MF/SS. In this review, we highlight these recent advancements, ranging from optimization of skin-directed therapies to the introduction of novel systemic agents. We focus on therapies approved in the preceding five years or under investigation in advanced-phase clinical trials.

Treatment of Adult T-Cell Leukemia/Lymphoma: Established Paradigms and Emerging Directions

OPINION STATEMENT

Adult T-cell leukemia/lymphoma (ATL) is a rare, aggressive subtype of peripheral T-cell lymphoma developing after many years of chronic, asymptomatic infection with the retrovirus human T-cell lymphotropic virus type 1 (HTLV-1). HTLV-1 is endemic to certain geographic areas of the world, and primary infection generally occurs in infancy through mother-to-child transmission via breastfeeding. In less than 5% of infected individuals, a decades-long pathogenic process culminates in the development of ATL. Aggressive subtypes of ATL are life-threatening and challenging to treat, with median overall survival typically less than 1 year in the absence of allogeneic hematopoietic cell transplantation (alloHCT). Owing to the rarity of this illness, prospective large-scale clinical trials have been challenging to perform, and treatment recommendations are largely founded upon limited evidence. Herein, we review the current therapeutic options for ATL, providing a broad literature overview of the foremost clinical trials and reports of this disease. We emphasize our own treatment paradigm, which is broadly based upon disease subtype, patient fitness, and intent to perform alloHCT. Finally, we highlight recent advances in understanding ATL disease biology and important ongoing clinical trials that we foresee as informative and potentially practice-changing.

Functional heterogeneity of human skin-resident memory T cells in health and disease

The human skin is populated by a diverse pool of memory T cells, which can act rapidly in response to pathogens and cancer antigens. Tissue-resident memory T cells (TRM ) have been implicated in range of allergic, autoimmune and inflammatory skin diseases. Clonal expansion of cells with TRM properties is also known to contribute to cutaneous T-cell lymphoma. Here, we review the heterogeneous phenotypes, transcriptional programs, and effector functions of skin TRM . We summarize recent studies on TRM formation, longevity, plasticity, and retrograde migration and contextualize the findings to skin TRM and their role in maintaining skin homeostasis and altered functions in skin disease.

SOHO State of the Art Updates and Next Questions | A Modern Approach to the Systemic Treatment of Advanced CTCL

The term cutaneous T-cell lymphoma (CTCL) is a general term for T-cell lymphomas that are found primarily in skin. The most common CTCL entities, mycosis fungoides and Sezary syndrome are incurable diseases with a plethora of conventional treatment options. In the past treatment options have been selected primarily according to stage. Given newer targeted therapies with varied response in different body compartments, we suggest a compartment-guided algorithm that may enhance response rates directing the selection of the most efficacious treatment options.

Advances in the treatment of HTLV-1-associated adult T-cell leukemia lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive hematologic malignancy linked to HTLV-1 infection, which is refractory to therapy. The precise mechanism of oncogenesis in ATLL is incompletely understood, however, oncogenic viral genes Tax and Hbz are implicated, and recent large genomic and transcriptome studies provide further insight. Despite progress in understanding the disease, survival and outcome with current therapies remain poor. Long-term survivors are reported, primarily among those with indolent disease or activating CC chemokine receptor 4 mutations, however, allogeneic hematopoietic stem cell transplant is the only curative treatment option. The majority of patients succumb to their disease and ongoing and collaborative research efforts are needed. I will review recent updates in HTLV-1-associated ATLL epidemiology, pathogenesis, therapy, and prevention.

Management of relapsed cutaneous T-Cell lymphoma following allogeneic hematopoietic stem cell transplantation: Review with representative patient case

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment option for patients with refractory cutaneous T-cell lymphoma (CTCL) through replacement of the bone marrow responsible for lymphoma cells and possibly induction of a graft-versus-lymphoma effect. However, allo-HSCT is not always curative; relapse of CTCL occurs in about half of patients post-transplant. Treatment of relapsed CTCL after allo-HSCT is challenging because post-transplant patients are at high risk of graft-versus-host disease, and this condition may be precipitated or exacerbated by standard CTCL therapies. The benefit of each potential therapy must therefore be weighed against its risk of graft versus host disease (GVHD). In this article, we review the management of relapsed CTCL after allo-HSCT. We begin with an exemplative patient whose relapsed Sezary syndrome was successfully treated without development of GVHD. We also report high-throughput T-cell receptor sequencing data obtained during the patient's disease relapse and remission. We then review general guidelines for management of relapsed CTCL and summarize all reported cases and outcomes of relapsed CTCL after transplant. We conclude by reviewing the current CTCL therapies and their risk of GVHD.

Impact of Human T Cell Lymphotropic Virus Type 1 and 2 Infection on Survival Following Stem Cell Transplantation

Human T cell lymphotropic virus types 1 and 2 (HTLV-1/2) are delta retroviruses. HTLV-1 may lead to complications, including adult T cell leukemia-lymphoma (ATLL) and HTLV-1-associated myelopathy. Immunosuppression may result in progression from an asymptomatic carrier state to ATLL. Data on the safety of stem cell transplantation (SCT) in patients with HTLV-1/2 infection are lacking. The Center for International Blood and Marrow Transplant Research database was queried for patients who tested positive for HTLV infection in the pretransplantation workup and underwent either autologous SCT (autoSCT) or allogeneic SCT (alloSCT). Patients were excluded if they underwent SCT for ATLL. The primary outcome was overall survival (OS) at 3 years and 4 years post-SCT. In those who underwent autoSCT, 54 patients were HTLV-positive and 9836 were HTLV-negative. In those who underwent alloSCT, 105 patients were HTLV-positive and 18,077 were HTLV-negative. No difference in OS was noted between the HTLV-positive and HTLV-negative patients at 3 years post-autoSCT (76% versus 77%; P = .916). Inferior OS (32% versus 46%; P = .017) and nonrelapse mortality (35% versus 27%; P = .030) were observed in HTLV-positive patients at 4 years post-alloSCT. Future work should examine the mechanism by which HTLV-1/2 impact survival in alloSCT recipients.

Current treatment strategies and emerging therapies for cutaneous lymphoma

Cutaneous lymphoma is generally treated with skin-directed therapies (SDT) during the early and localized stages. For the refractory or advanced stages, systemic therapies are used. Previously, retinoids and interferons were used for SDT-resistant cases. Only a few chemotherapy options were available for more advanced disease. In recent years, many novel agents have been introduced and the strategy for systemic therapy has changed, especially for cutaneous T-cell lymphoma (CTCL). For SDT, helical tomotherapy, a new radiation modality, has been drawing attention as an option for radiotherapy. Targeted therapies such as histone deacetylase inhibitors, mogamulizumab, brentuximab vedotin, and denileukin diftitox are new treatment options. Chemotherapy agents such as gemcitabine and pralatrexate have been introduced; they are expected to have meaningful efficacy as monotherapy. Allogeneic hematopoietic stem cell transplantation is still considered for young patients with advanced CTCL as the only potentially curative treatment.

Acute Pulmonary Graft-Versus-Host Disease in a Patient with Adult T-cell Leukemia-Lymphoma Diagnosed by a Cryobiopsy

A 51-year-old woman with adult T-cell leukemia-lymphoma was hospitalized in order to undergo allogeneic hematopoietic stem-cell transplantation. On day 29 after transplantation, she began to experience hypoxia upon exertion. Chest computed tomography revealed centrilobular granular shadows, and pulmonary function tests revealed a remarkable obstructive ventilatory impairment compared to before transplantation. A histopathological analysis following a transbronchial lung cryobiopsy revealed acute graft-versus-host disease (GVHD). We herein report a rare case of histopathologically diagnosed acute pulmonary GVHD with spontaneous remission.

How I treat adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive T-cell malignancy that arises in a proportion of individuals who are long-term carriers of human T-lymphotropic virus type 1. The median survival of aggressive subtypes is 8 to 10 months; with chemotherapy-based approaches, overall survival has remained largely unchanged in the ∼35 years since ATL was first described. Through the use of 4 representative case studies, we highlight advances in the biological understanding of ATL and the use of novel therapies such as mogamulizumab, as well as how they are best applied to different subtypes of ATL. We discuss the implementation of molecular methods that may guide diagnosis or treatment, although we accept that these are not universally available. In particular, we acknowledge discrepancies in treatment between different countries, reflecting current drug licensing and the difficulties in making treatment decisions in a rare disease, with limited high-quality clinical trial data.

Allogeneic Stem Cell Transplantation in Mature T Cell and Natural Killer/T Neoplasias: A Registry Study from Spanish GETH/GELTAMO Centers

Despite advances in understanding the biology of mature T and natural killer (NK)/T cell neoplasia, current therapies, even the most innovative ones, are still far from ensuring its cure. The only treatment to date that has been shown to control aggressive T cell neoplasms in the long term is allogeneic stem cell transplantation (alloSCT). We aim to report the results of alloSCT for advanced mature T and NK/T neoplasias performed in centers from our national GELTAMO/GETH (Grupo Español de Linfoma y Trasplante de Médula Ósea/Grupo Español de Trasplante Hematopoyético y Terapia Celular) over the past 25 years. As a secondary objective, we analyzed the results of alloSCT from haploidentical donors. We performed a retrospective analysis of all patients who received an alloSCT in Spanish centers (n = 201) from September 1995 to August 2018. The 2-year overall survival (OS) and disease-free survival (DFS) were 65.5% and 58.2%, respectively. The univariate for OS and DFS showed statistically different hazard ratios for conditioning intensity, response pre-alloSCT, comorbidity index, donor/receptor cytomegalovirus status and Eastern Cooperative Oncology Group (ECOG) pre-alloSCT, but only a better ECOG pre-alloSCT remained significant in the multivariate analysis. There was an increased incidence of relapse in those patients who did not develop chronic graft-versus-host disease (GVHD) and an increased risk of death in those developing moderate to severe acute GVHD. The 1-year nonrelapse mortality was 21.9% and was mainly due to GVHD (30%) and bacterial infections (17%). When comparing unrelated donors with haploidentical donors, we found similar results in terms of OS and DFS. There was, however, a reduction of acute GVHD in the haploidentical group (P = .04) and trend to a reduction of chronic GVHD. In conclusion, alloSCT is the only curative option for most aggressive T cell neoplasias. Haploidentical donors offer similar results to related donors in terms of survival with a reduction of acute GVHD.

Diagnosis and management of adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell malignancy caused by human T-cell leukemia virus type I (HTLV-1). Between 3% and 5% of HTLV-1-infected individuals develop ATL after a long latency. Confirmation of seropositivity of anti-HTLV-1 antibody, and clonal proliferation of CD4 and CD25 positive lymphocytes with nuclear pleomorphism in patients suspicious of malignant lymphoma or chronic lymphocytic leukemia is crucial for the diagnosis of ATL. The clinical course of ATL is very heterogeneous, and divided into acute, lymphoma, chronic, and smoldering types. The chronic type is further subclassified into the favorable and unfavorable subtypes. Acute, lymphoma, and unfavorable chronic type ATL, and favorable chronic and smoldering type ATL are defined as aggressive and indolent ATL, respectively. Recently identified prognostic indices based on clinical parameters and/or genetic predictors of outcomes need to be confirmed and incorporated for more stratified therapeutic interventions. The standard of care for aggressive ATL is multiagent chemotherapy followed by allogeneic hematopoietic stem cell transplantation if possible, while that for indolent ATL is watchful waiting until progression to aggressive ATL. The combination of interferon-α and zidovudine is also standard for leukemic type ATL. In addition, mogamulizumab, lenalidomide, and brentuximab vedotin have been incorporated into clinical practices in Japan. Furthermore, several novel drugs are currently undergoing clinical trials.

Outlines of the Japanese guidelines for the management of primary cutaneous lymphomas 2020

Since the publication of the Japanese "Guidelines for the management of cutaneous lymphomas" in 2011, the World Health Organization (WHO) classification of hematolymphoid neoplasms and the WHO-European Organisation for Research and Treatment of Cancer classification for primary cutaneous lymphomas were updated and a number of novel systemic drugs for cutaneous T-cell lymphoma had been approved in Japan. In 2020, we revised the Japanese guidelines for the management of cutaneous lymphomas with consideration of the recent advances in the understanding of the pathophysiology and classification of cutaneous lymphomas together with the update of treatment strategies reflecting the advent of novel drugs. In addition to a brief explanation of epidemiology, diagnosis, staging system, prognosis and management of each subtype of cutaneous lymphomas, the recommendations for nine clinical questions regarding treatment options that can vary even among experts are also described. A systematic review process and determination of recommendations in answer to each clinical question have been performed in accordance with the Grading of Recommendations, Assessment, Development and Evaluation scheme by a multidisciplinary expert panel consisting of dermatologists, a hematologist and a radiation oncologist. In this article, we present the outlines of the revised Japanese "Guidelines for the management of cutaneous lymphomas".

Spotlight on Mogamulizumab-Kpkc for Use in Adults with Relapsed or Refractory Mycosis Fungoides or Sézary Syndrome: Efficacy, Safety, and Patient Selection

Advanced cutaneous T cell lymphomas (CTCL) including mycosis fungoides (MF) and Sézary syndrome (SS) are often difficult to manage once they become resistant to initial systemic treatment. Current systemic treatments usually provide a limited duration of disease control, leaving this an area in desperate need of new treatment options for better long-term control. These conditions often affect the older population where transplantation may not be a feasible option. Recent studies evaluated a novel CCR4 humanized monoclonal antibody, mogamulizumab, in relapsed/refractory MF and SS, which show a meaningful progression free survival (PFS) benefit. In August 2018, mogamulizumab was approved by the FDA for the treatment of patients with relapsed/refractory MF/SS who have failed at least one treatment. Approval was based on the Phase III MAVORIC study comparing mogamulizumab to vorinostat, an FDA approved drug for this indication, in 372 patients. In this trial, mogamulizumab was found to have a superior PFS with a median of 7.7 months compared to 3.1 months in the vorinostat arm, with a hazard ratio of 0.53, p<0.001. Mogamulizumab was well tolerated with the most common AE being infusion-related reactions (32%), drug rash (20%), diarrhea (23%), and fatigue (22%). We reviewed the literature leading to the development and approval of mogamulizumab and suggest which patients may benefit the most from this treatment.

Clinical efficacy of mogamulizumab for relapsed/refractory aggressive adult T-cell leukemia/lymphoma: A retrospective analysis

OBJECTIVES

Although phase 2 studies have confirmed the efficacy of mogamulizumab for adult T-cell leukemia/lymphoma (ATL), real-world data on its benefits are limited. We assessed the benefits of mogamulizumab for relapsed/refractory ATL in clinical practice.

METHODS

We retrospectively analyzed patients with acute- and lymphoma-type ATL. Among 57 patients diagnosed with ATL between January 2008 and August 2018, 42 who received salvage therapy were eligible, including 24 who received mogamulizumab.

RESULTS

The overall response rate to mogamulizumab was 54.2%. Median survival time (MST) and 1-year overall survival (OS) rate from mogamulizumab initiation were 7.7 months and 42.0%, respectively. Patients with acute-type ATL showed longer MST (15.1 months) and higher 1-year OS (63.6%). MST without skin rash was 5.0 months, and 1-year OS was 34.3%; however, MST with skin rash was not reached and 1-year OS was 66.7%. Among patients who received the salvage therapy, longer MST and higher 1-year OS were observed with mogamulizumab than without mogamulizumab (P = .078; 9.2 vs. 3.9 months; 47.9% vs. 17.6%, respectively). Mogamulizumab administration improved prognosis in patients with acute-type ATL and skin rash.

CONCLUSIONS

In clinical practice, mogamulizumab improved OS in patients with relapsed/refractory ATL, especially those with acute-type ATL and skin rash.

Diagnostic Approaches and Established Treatments for Adult T Cell Leukemia Lymphoma

Adult T-cell leukemia-lymphoma (ATL) is a distinct mature T-cell malignancy caused by human T-cell leukemia/lymphotropic virus type I (HTLV-1) endemic in some areas in the world. HTLV-1 transmits through mother-to-child infection via breastfeeding, sexual intercourses, and blood transfusions. Early HTLV-1 infection, presumably through mother’s milk, is crucial in developing ATL. The estimated cumulative risk of the development of ATL in HTLV-1 carriers is a few percent after transmission from their mothers. The median age of ATL onset is about 70 in Japan and is now rising, whereas an overall mean age in the mid-forties is reported in other parts of the world. ATL is classified into four clinical subtypes (acute, lymphoma, chronic, and smoldering) defined by organ lesions and LDH/calcium values. In aggressive ATL (acute, lymphoma or unfavorable chronic types) and indolent ATL (favorable chronic or smoldering types), intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation and watchful waiting until disease progression has been recommended, respectively, in Japan. Based on a worldwide meta-analysis and multiple other retrospective studies, the antiviral combination of interferon alpha (IFN) and zidovudine (AZT) is recommended in many parts of the world in acute, chronic, and smoldering ATL whereas patients with the lymphoma subtype are treated with chemotherapy, either alone or combined with AZT/IFN. Several new agents have been approved for ATL by the Pharmaceutical and Medical Devices Agency (PMDA) after clinical trials, including an anti-CC chemokine receptor 4 monoclonal antibody, mogamulizumab; an immunomodulatory agent, lenalidomide; and an anti-CD30 antibody/drug conjugate, brentuximab vedotin.

Eligibility Criteria for Patients Undergoing Allogeneic Hematopoietic Cell Transplantation

Eligibility assessment of a potential candidate for allogeneic hematopoietic cell transplantation (allo-HCT) is a complex yet vital component of pretransplant evaluation. Although no formal standardized consensus exists to guide this process, transplant centers follow institutional standard operating procedures and parameters to approve candidacy of an individual patient. Consideration for allo-HCT is dependent on a myriad of interrelated factors, including disease-related (eg, appropriate indication, disease status, prior therapies), patient-related (eg, age, functional status, frailty, comorbidities), psychosocial, and economic factors. A multidisciplinary approach is optimal for patient selection and requires the efforts of transplant coordinators, nurses, advanced practice providers, social workers, psychologists, financial specialists, and physicians. This article reviews the data and provides general guidelines that may be used in making an informed decision when evaluating a prospective candidate for allo-HCT. These recommendations are based on published data, expert commentary, reviews, and institutional practices. In the end, the eligibility assessment and decision to consider allo-HCT as the optimal choice of treatment for an individual patient are truly as much an "art" as it is the "science" of medicine, encompassing a multidisciplinary approach to minimize harm without compromising the curative potential-all essential doctrines of the Hippocratic Oath.

Mogamulizumab in the treatment of advanced mycosis fungoides and Sézary syndrome: safety and efficacy

INTRODUCTION

Advanced mycosis fungoides (MF) and Sézary syndrome (SS) are forms of cutaneous T-cell lymphoma characterized by a poor prognosis. Treatments are associated with high rates of relapse, and thus there exists an unmet medical need for new, improved therapies. Mogamulizumab is a novel defucosylated monoclonal antibody targeting C-C chemokine receptor 4 that eradicates malignant cells via antibody-dependent cellular cytotoxicity (ADCC).

AREAS COVERED

Phase I-III clinical trials involving mogamulizumab demonstrated its significant efficacy and tolerability. In the phase III MAVORIC study, mogamulizumab exhibited greater efficacy than vorinostat (response rate, 28% versus 5%; median progression-free survival, 7.7 versus 3.1 months, respectively) for advanced, relapsed/refractory MF/SS. Responses were durable (median, 14.1 months), and response rates were highest in SS (37%) and within the blood compartment (68%). Common adverse events include infusion reactions and drug eruptions. The drug also increases the risk of immune-mediated complications such as autoimmune disease and acute graft-versus-host disease following transplantation.

EXPERT OPINION

Mogamulizumab represents a valuable therapy for advanced MF/SS as it can produce prolonged responses, particularly within the peripheral blood. Since it eliminates malignant T cells via ADCC, combining mogamulizumab with immunotherapeutic agents such as interferons, interleukin-12, and Toll-like receptor agonists may further enhance its efficacy.

Reduced-intensity haploidentical peripheral blood stem cell transplantation using low-dose thymoglobulin for aggressive adult T cell leukemia/lymphoma patients in non-complete remission

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been accepted as a treatment option for aggressive (acute or lymphoma type) adult T cell leukemia/lymphoma (ATLL) patients with a poor prognosis, when a suitable HLA-matched donor is not available. However, haplo-HSCT carries a potential risk of treatment-related mortality including severe graft-versus-host disease (GVHD). Therefore, we conducted a prospective pilot study in order to evaluate the efficacy and safety of reduced-intensity haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with low-dose thymoglobulin (2.5 mg/kg only on day −2), fludarabine, melphalan, and total body irradiation 4 Gy for aggressive ATLL. Three consecutive acute type ATLL patients, who were ineligible for conventional myeloablative conditioning due to advanced age or comorbidities, were enrolled. One patient received pretransplant mogamulizumab therapy. All the patients were not in complete remission (CR) at the time of transplantation. Our transplantation protocol was safely carried out. CR was achieved in all the patients after transplantation. HTLV-I viral loads became undetectable after transplantation. No severe adverse events such as grade III-IV GVHD or viral/fungal diseases were observed. At a follow-up of 2 years, they were still in CR. However, T cell receptor repertoire diversities were low 1 year after transplantation in next-generation sequencing. Our results show encouraging therapeutic benefits of this pilot approach using reduced-intensity haplo-PBSCT with low-dose thymoglobulin for aggressive ATLL patients.

Progress in Allogeneic Hematopoietic Cell Transplantation in Adult T-Cell Leukemia-Lymphoma

The prognosis of aggressive adult T-cell leukemia-lymphoma (ATL) remains poor because of frequent infections and drug resistance. Dose-intensified chemotherapy followed by autologous stem cell transplantation failed to improve the prognosis of patients with ATL; however, we first revealed that allogeneic hematopoietic cell transplantation (allo-HCT) might improve their prognosis. We showed that reduced-intensity stem cell transplantation using peripheral blood was feasible for elderly patients. Further, the prognosis of patients in remission, who receive cord blood transplantation, has been recently improved and is equivalent to that of patients who receive transplants from other stem cell sources. As for the timing of HCT, the patients who underwent transplantation early showed better outcomes than those who underwent transplantation late. Based on the analysis of patients with aggressive ATL, including those who received transplants, we identified five prognostic factors for poor outcomes: acute-type ATL, poor performance status, high soluble interleukin-2 receptor levels, hypercalcemia, and high C-reactive protein level. Next, we developed a new prognostic index: the modified ATL-PI. The overall survival (OS) rates were significantly higher in patients who underwent allo-HCT than those who did not in the intermediate and high-risk groups stratified using the modified ATL-PI. Two new anti-cancer agents, mogamulizumab and lenalidomide, were recently approved for ATL patients in Japan. They are expected to induce longer survival in ATL patients when administered along with transplantation. However, a retrospective analysis that the risk of severe, acute, and corticosteroid-refractory graft-versus-host disease was higher in patients who received mogamulizumab before allo-HCT, and that mogamulizumab might increase the transplant-related mortality (TRM) rates and decrease the OS rates compared to those of patients who did not receive mogamulizumab. However, our recent study showed that administration of mogamulizumab before allo-HCT tended to improve the survival of patients with ATL. In conclusion, allo-HCT procedures for patients with aggressive ATL have considerably progressed and have helped improve the prognosis of these patients; however, many concerns still remain to be resolved. Further development of allo-HCT by using new molecular targeting agents is required for the improvement of cure rates in patients with ATL.

Plasma exchange eliminates residual mogamulizumab but does not warrant prompt recovery of peripheral Treg levels

Mogamulizumab (Mog), a humanized anti-CCR4 antibody, provides an important treatment option for relapsed/refractory adult T cell leukemia/lymphoma. However, administration of Mog before allogenic hematopoietic stem cell transplantation has been reported to be a risk factor for severe acute graft-versus-host disease (GVHD). The etiological hypothesis is Mogamulizumab may eradicate CCR4-positive regulatory T cells (Tregs). Theoretically, Treg homeostasis and course of GVHD can be affected by plasma exchange (PE) with decreasing plasma Mog concentration. Here, we present a case of severe acute GVHD after pretransplantation Mog, in which PE was performed for liver failure. As a result, plasma Mog concentration was decreased but it did not lead to the prompt elevation of Treg levels in peripheral blood and clinical responses of GVHD were limited to partial remission. Our case suggests that recovery of donor-derived Treg in the acute phase after HSCT is multifactorial and the single procedure of PE-based Mog depletion does not necessarily warrant the quick restoration of Treg homeostasis.

Smoldering type adult T-cell leukemia/lymphoma effectively treated with mogamulizumab (anti-CC chemokine receptor 4 monoclonal antibody)-A case report

The use of mogamulizumab needs careful consideration because of severe adverse reactions such as graft-vs-host disease. However, refractory specific skin lesions of smoldering type adult T-cell leukemia/lymphoma can be effectively treated with mogamulizumab when patients have no opportunity to receive hematopoietic stem cell transplantation like our case.

Mogamulizumab for the Treatment of Adult T-cell Leukemia/Lymphoma

Mogamulizumab, a defucosylated humanized monoclonal antibody against the C-C chemokine receptor 4 (CCR4), has been approved for the treatment of relapsed adult T-cell leukemia/lymphoma (ATL). Compared with conventional chemotherapy, mogamulizumab monotherapy displayed more efficacy in relapsed ATL, making mogamulizumab a promising therapeutic agent. However, mogamulizumab could increase graft-versus-host disease, resulting in poor survival outcome in the allogenic stem cell transplant (allo-SCT) setting. It is possible that the efficacy of mogamulizumab could be established by the occurrence of skin rashes and/or CCR4 mutational status. Hence, this study reviews the current treatment strategies for patients with ATL and focuses on the safety and efficacy (single-agent and combined with chemotherapy or allo-SCT) of mogamulizumab.

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.

An activating mutation of interferon regulatory factor 4 (IRF4) in adult T-cell leukemia

The human T-cell leukemia virus-1 (HTLV-1) oncoprotein Tax drives cell proliferation and resistance to apoptosis early in the pathogenesis of adult T-cell leukemia (ATL). Subsequently, probably as a result of specific immunoediting, Tax expression is down-regulated and functionally replaced by somatic driver mutations of the host genome. Both amplification and point mutations of interferon regulatory factor 4 (IRF4) have been previously detected in ATL., K59R is the most common single-nucleotide variation of IRF4 and is found exclusively in ATL. High-throughput whole-exome sequencing revealed recurrent activating genetic alterations in the T-cell receptor, CD28, and NF-κB pathways. We found that IRF4, which is transcriptionally activated downstream of these pathways, is frequently mutated in ATL. IRF4 RNA, protein, and IRF4 transcriptional targets are uniformly elevated in HTLV-1-transformed cells and ATL cell lines, and IRF4 was bound to genomic regulatory DNA of many of these transcriptional targets in HTLV-1-transformed cell lines. We further noted that the K59R IRF4 mutant is expressed at higher levels in the nucleus than WT IRF4 and is transcriptionally more active. Expression of both WT and the K59R mutant of IRF4 from a constitutive promoter in retrovirally transduced murine bone marrow cells increased the abundance of T lymphocytes but not myeloid cells or B lymphocytes in mice. IRF4 may represent a therapeutic target in ATL because ATL cells select for a mutant of IRF4 with higher nuclear expression and transcriptional activity, and overexpression of IRF4 induces the expansion of T lymphocytes in vivo.

A Review of New Findings in Adult T-cell Leukemia-Lymphoma: A Focus on Current and Emerging Treatment Strategies

Adult T-cell leukemia–lymphoma (ATL), a rare and aggressive T-cell malignancy caused by human T-cell lymphotropic virus type 1 (HTLV-1), is associated with a poor prognosis. Evidence-based standard treatment options are lacking and outcomes are generally unsatisfactory, particularly for patients with relapsed or refractory disease. Continued research is contributing to changing treatment landscape as a number of existing and investigational agents are evaluated. We describe the epidemiology of HTLV-1 and ATL, discuss the biology behind the disease, review current treatment practices and guidelines, and provide an overview of emerging therapies in ATL, with a focus on those for relapsed or refractory disease.

Safety and efficacy of mogamulizumab in patients with adult T-cell leukemia-lymphoma in Japan: interim results of postmarketing all-case surveillance

We present the interim results of a postmarketing all-case surveillance study in patients with C-C chemokine receptor 4 (CCR4)-positive, relapsed or refractory adult T-cell leukemia-lymphoma (ATL) treated with the anti-CCR4 monoclonal antibody mogamulizumab since its 2012 launch in Japan. The safety and efficacy analysis populations comprised 484 and 442 patients, respectively. The ATL subtype was acute in 58.9% and lymphoma in 34.2% of patients. All patients were scheduled to receive intravenous infusions of mogamulizumab (1.0 mg/kg) once weekly for eight weeks, alone or in combination with other modalities. Adverse drug reactions (ADRs) were reported in 74.0% of patients, of which 35.7% were serious and 6.2% were fatal. The priority survey items of infusion-related reaction, skin disorder, infection, immune disorder, and tumor lysis syndrome were reported in 29.3, 34.3, 22.1, 3.5, and 2.5% of patients, respectively. Graft-versus-host disease was reported in 25/42 patients who received mogamulizumab before allogeneic hematopoietic stem cell transplantation. The best overall response rate was 57.7% overall, 57.5% in patients treated with mogamulizumab alone, and 58.2% in patients treated with combination therapy. This surveillance indicates that mogamulizumab shows acceptable tolerability in practice; however, because of the risk of serious/fatal ADRs, patients administered mogamulizumab should be carefully monitored.

Friend or foe? Mogamulizumab in allogeneic hematopoietic stem cell transplantation for adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL/ATLL) is a peripheral T-cell neoplasm associated with human T-lymphotropic virus type-1 (HTLV-1). Even the currently most intensive chemotherapy regimen modified LSG15 (mLSG15, VCAP-AMP-VECP) results in a dismal clinical outcome, with a median overall survival of only around 1 year. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) may lead to long-term remission in a proportion of patients with aggressive ATL, the clinical outcome in patients with refractory or relapsed ATL is unsatisfactory. The anti-CCR4 antibody mogamulizumab (moga) has been recently approved for ATL in Japan, and it is effective in a significant proportion of patients with refractory or relapsed ATL. However, there are major concerns about the harmful influences of pretransplant moga on the immune reconstitution after allo-HSCT. Specifically, moga depletes regulatory T cells (Tregs) for at least a few months, which may increase the risk of graft-versus-host disease (GVHD) after allo-HSCT. A recent retrospective study from Japan clearly showed that pretransplant moga increased the risk of severe and steroid-refractory GVHD, which led to increases in non-relapse mortality and overall mortality. To improve the overall clinical outcome in patients with relapsed or refractory ATL, more studies are needed to incorporate moga without increasing adverse effects on the clinical outcome after allo-HSCT. In this review, we aim to provide an updated summary of the research related to moga and allo-HSCT.

T-cell lymphomas, a challenging disease: types, treatments, and future

T-cell lymphomas are rare and aggressive malignancies associated with poor outcome, often because of the development of resistance in the lymphoma against chemotherapy as well as intolerance in patients to the established and toxic chemotherapy regimens. In this review article, we discuss the epidemiology, pathophysiology, current standard of care, and future treatments of common types of T-cell lymphomas, including adult T-cell leukemia/lymphoma, angioimmunoblastic T-cell lymphoma, anaplastic large-cell lymphoma, aggressive NK/T-cell lymphoma, and cutaneous T-cell lymphoma.

Successful treatment with mogamulizumab followed by allogeneic hematopoietic stem-cell transplantation in adult T-cell leukemia/lymphoma: a report of two cases

A humanized anti-CC chemokine receptor 4 (CCR4) monoclonal antibody, mogamulizumab (MOG), has been shown to be safe and effective in the treatment of relapsed/refractory adult T-cell leukemia/lymphoma (ATLL). MOG depletes ATLL cells as well as regulatory T cells (Tregs), as CCR4 is expressed on these cells as well. In this context, pretransplant treatment with MOG may induce severe graft-versus-host disease (GVHD) in allogeneic hematopoietic stem-cell transplantation (HSCT). However, the influence of MOG on allogeneic HSCT, including its induction of GVHD, is unclear. In this report, we describe two patients treated with MOG who subsequently underwent allogeneic HSCT. They did not develop severe GVHD or treatment-related complications. In addition, we examined the kinetics of Tregs in the second case. Finally, we suggest that the detrimental effects of MOG can be avoided, which should be prospectively evaluated in future studies.