Outcome of patients with HTLV-1-associated adult T-cell leukemia/lymphoma after SCT: a retrospective study by the EBMT LWP

Outcomes in human T-cell leukemia virus type I carriers after hematopoietic stem cell transplantation for diseases other than adult T cell leukemia/lymphoma: a Japanese national survey

Background

Human T-cell leukemia virus type I (HTLV-1) is a retrovirus known to cause adult T-cell leukemia/lymphoma (ATL). There are few reports on hematopoietic stem cell transplantation (HSCT) for HTLV-1 carriers with diseases other than ATL.

Methods

A total of 25,839 patients (24,399 adults and 1440 children) with pre-transplant HTLV-1 serostatus information recorded in the Japanese National Survey Database who had undergone their first HSCT were analyzed. We investigated the overall survival (OS), transplant-related mortality (TRM), and disease-related mortality (DRM) after HSCT in relation to HTLV-1 serologic status.

Findings

Three hundred and forty-eight patients were HTLV-1 antibody carriers. The number of HTLV-1 carriers and noncarriers among adult patients who received allogeneic HSCT (allo-HSCT) or autologous HSCT (auto-HSCT) was 237/15,777 and 95/8920, respectively, and was 16/1424 among pediatric patients who received allo-HSCT. No pediatric HTLV-1 carrier recipients undergoing auto-HSCT were identified. There were no significant differences between HTLV-1 carriers and non-carriers regarding stem cell source, disease risk, or HCT-CI score prior to allo-HSCT. Multivariate analysis of OS (P = 0.020) and TRM (P = 0.017) in adult patients showed that HTLV-1 positive status was a significant prognostic factor. In children, TRM was significantly higher (P = 0.019), but OS was not significantly different. In adult patients who underwent auto-HSCT, HTLV-1 positive status was not a significant prognostic factor. In adult allo-HSCT patients, cytomegalovirus reactivation was significantly more common in HTLV-1 carriers (P = 0.001).

Interpretation

HTLV-1 antibody positivity was shown to have a poor prognosis in OS and TRM after allo-HSCT in adult patients and in TRM after allo-HSCT in pediatric patients.

Funding

This work was supported in part by the practical research programs of the Japan Agency for Medical Research and Development (AMED) under grant number 17ck0106342h0001.

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.

Outcome of Stem Cell Transplantation in HTLV-1-Associated North American Adult T-Cell Leukemia/Lymphoma

Adult T-cell leukemia/lymphoma (ATLL) remains challenging to treat and has dismal outcome. Allogeneic stem-cell transplantation (allo-SCT) has promising results, but data remain scarce. In this single-center retrospective analysis of 100 patients with ATLL from north America (67 acute, 22 lymphomatous), 17 underwent allo-SCT and 5 autologous SCT (ASCT), with a median follow-up of 65 months. Post-transplant 3-years relapse incidence (RI) and non-relapse mortality (NRM) were 51% and 37%, respectively, and 3-year progression-free survival (PFS) and overall survival (OS) were 31% and 35%, respectively. ASCT 1-year RI was 80% compared to 30% in allo-SCT (p = 0.03). After adjusting for immortal-time bias, allo-SCT had significantly improved OS (HR = 0.4, p = 0.01). In exploratory multivariate analysis, patients achieving first complete response and Karnofsky score ≥ 90 had significantly better outcomes, as did Black patients, compared to Hispanics, who had worse outcome. In transplanted patients, 14 died within 2 years, 4 of which ASCT recipients. Our data are the largest ATLL transplant cohort presented to date outside of Japan and Europe. We show that allo-SCT, but not ASCT, is a valid option in select ATLL patients, and can induce long term survival, with 40% of patients alive after more than 5 years.

Deciphering the roles of myeloid derived suppressor cells in viral oncogenesis

Myeloid derived suppressor cells (MDSCs) are a heterogenous population of myeloid cells derived from monocyte and granulocyte precursors. They are pathologically expanded in conditions of ongoing inflammation where they function to suppress both innate and adaptive immunity. They are subdivided into three distinct subsets: monocytic (M-) MDSC, polymorphonuclear (or neutrophilic) (PMN-) MDSC and early-stage (e-) MDSC that may exhibit differential function in different pathological scenarios. However, in cancer they are associated with inhibition of the anti-tumour immune response and are universally associated with a poor prognosis. Seven human viruses classified as Group I carcinogenic agents are jointly responsible for nearly one fifth of all human cancers. These viruses represent a large diversity of species, including DNA, RNA and retroviridae. They include the human gammaherpesviruses (Epstein Barr virus (EBV) and Kaposi's Sarcoma-Associated Herpesvirus (KSHV), members of the high-risk human papillomaviruses (HPVs), hepatitis B and C (HBV, HCV), Human T cell leukaemia virus (HTLV-1) and Merkel cell polyomavirus (MCPyV). Each of these viruses encode an array of different oncogenes that perturb numerous cellular pathways that ultimately, over time, lead to cancer. A prerequisite for oncogenesis is therefore establishment of chronic infection whereby the virus persists in the host cells without being eradicated by the antiviral immune response. Although some of the viruses can directly modulate the immune response to enable persistence, a growing body of evidence suggests the immune microenvironment is modulated by expansions of MDSCs, driven by viral persistence and oncogenesis. It is likely these MDSCs play a role in loss of immune recognition and function and it is therefore essential to understand their phenotype and function, particularly given the increasing importance of immunotherapy in the modern arsenal of anti-cancer therapies. This review will discuss the role of MDSCs in viral oncogenesis. In particular we will focus upon the mechanisms thought to drive the MDSC expansions, the subsets expanded and their impact upon the immune microenvironment. Importantly we will explore how MDSCs may modulate current immunotherapies and their impact upon the success of future immune-based therapies.

HTLV-1-related adult T-cell leukemia/lymphoma: insights in early detection and management

PURPOSE OF REVIEW

Adult T-cell leukemia-lymphoma (ATL) is an aggressive mature T-cell malignancy that arises in approximately 5% of carriers of human T-lymphotropic virus type 1 (HTLV-1), but this risk is not random among carriers. We describe recent advance in pathogenesis, risk factors and for early detection of ATL.

RECENT FINDINGS

Unraveling ATL molecular genetics has shed light on pathogenesis and provides insights into novel therapeutic targets. Moreover, an important step in improving outcomes is identifying asymptomatic carriers who are at high risk of progression to ATL, which has traditionally relied on quantifying the proviral load (PVL). This can be done by quantifying oligoclonality- and in particular the expanded clone- with molecular and flow cytometric techniques, that can be applied to a clinical setting. Studies using these methods have shown that carriers with oligoclonal populations are at an increased risk of transformation, beyond that that predicted by PVL alone.

SUMMARY

There is an urgent unmet need for developing novel therapies in ATL in order to improve survival. Recent advances in the molecular and epigenetic landscape of ATL, and the early detection of disease offer the potential to intervene early, before disease becomes aggressive, and to offer tailored therapeutic strategies.

Interplay between innate immunity and the viral oncoproteins Tax and HBZ in the pathogenesis and therapeutic response of HTLV-1 associated adult T cell leukemia

The Human T-cell Leukemia virus type 1 (HTLV-1) causes an array of pathologies, the most aggressive of which is adult T-cell leukemia (ATL), a fatal blood malignancy with dismal prognosis. The progression of these diseases is partly ascribed to the failure of the immune system in controlling the spread of virally infected cells. HTLV-1 infected subjects, whether asymptomatic carriers or symptomatic patients are prone to opportunistic infections. An increasing body of literature emphasizes the interplay between HTLV-1, its associated pathologies, and the pivotal role of the host innate and adoptive immune system, in shaping the progression of HTLV-1 associated diseases and their response to therapy. In this review, we will describe the modalities adopted by the malignant ATL cells to subvert the host innate immune response with emphasis on the role of the two viral oncoproteins Tax and HBZ in this process. We will also provide a comprehensive overview on the function of innate immunity in the therapeutic response to chemotherapy, anti-viral or targeted therapies in the pre-clinical and clinical settings.

Adult T-Cell Leukemia: a Comprehensive Overview on Current and Promising Treatment Modalities

PURPOSE OF THE REVIEW

Adult T-cell leukemia (ATL) is an aggressive chemo-resistant malignancy secondary to HTLV-1 retrovirus. Prognosis of ATL remains dismal. Herein, we emphasized on the current ATL treatment modalities and their drawbacks, and opened up on promising targeted therapies with special focus on the HTLV-1 regulatory proteins Tax and HBZ.

RECENT FINDINGS

Indolent ATL and a fraction of acute ATL exhibit long-term survival following antiviral treatment with zidovudine and interferon-alpha. Monoclonal antibodies such as mogamulizumab improved response rates, but with little effect on survival. Allogeneic hematopoietic cell transplantation results in long-term survival in one third of transplanted patients, alas only few patients are transplanted. Salvage therapy with lenalidomide in relapsed/refractory patients leads to prolonged survival in some of them. ATL remains an unmet medical need. Targeted therapies focusing on the HTLV-1 viral replication and/or viral regulatory proteins, as well as on the host antiviral immunity, represent a promising approach for the treatment of ATL.

A Phase I/II Multicenter Trial of HLA-Haploidentical PBSCT with PTCy for Aggressive Adult T Cell Leukemia/Lymphoma

Adult T cell leukemia/lymphoma (ATL) is a highly aggressive hematologic malignancy with a very poor prognosis, and most patients with ATL are elderly. Although post-transplantation cyclophosphamide (PTCy) has yielded promising results in various diseases, available data are limited regarding its outcomes in ATL. The aim of this study was to determine the safety and efficacy of reduced-intensity peripheral blood stem cell transplantation (PBSCT) from a human leukocyte antigen (HLA)-haploidentical donor using PTCy as graft-versus-host disease (GVHD) prophylaxis. This was a prospective, multicenter phase I/II study (UMIN000021783) conducted at 16 hospitals in Japan. The primary endpoint was the probability of survival with engraftment and without grade III/IV acute GVHD at day 60 after PBSCT. The expected probability of the primary endpoint was estimated to be 60%, and the threshold probability was set at 30% on the basis of previous studies. The conditioning regimen consisted of fludarabine (30 mg/m²/d from day -7 to -2), melphalan (40 mg/m²/d on days -3 and -2), and total body irradiation (2 Gy on day -1). GVHD prophylaxis consisted of tacrolimus starting at 0.02 mg/kg/d on day -1, PTCy (50 mg/kg/d on days +3 and +5), and mycophenolate mofetil 2000 mg/d starting on day +6. Eighteen ATL patients underwent PBSCT. The probability of patients who met the primary endpoint was 89% (95% confidence interval, 65% to 99%). The cumulative incidences of grade II to IV acute GVHD, III/IV acute GVHD, and moderate-to-severe chronic GVHD were 39%, 11%, and 17%, respectively. The probabilities of overall survival were 83% at 1 year and 73% at 2 years. The cumulative incidences of non-relapse mortality and disease progression at 1 year were 11% and 28%, respectively. HLA-haploidentical PBSCT with PTCy as GVHD prophylaxis is a valid option for patients with aggressive ATL.

PD-1 and PD-L1 inhibitors foster the progression of adult T-cell Leukemia/Lymphoma

Immunotherapy through immune checkpoints blockade and its subsequent clinical application has revolutionized the treatment of a spectrum of solid tumors. Blockade of Programmed cell death protein-1 and its ligand has shown promising results in clinical studies. The clinical trials that enrolled patients with different hematopoietic malignancies including non-Hodgkin lymphoma, Hodgkin lymphoma, and acute myeloid leukemia (AML) showed that anti-PD-1 agents could have potential therapeutic effects in the patients. Adult T-cell leukemia/lymphoma (ATLL) is a non-Hodgkin T-cell Lymphoma that is developed in a minority of HTLV-1-infected individuals after a long latency period. The inhibition of PD-1 as a treatment option is currently being investigated in ATLL patients. In this review, we present a summary of the biology of the PD-1/PD-L1 pathway, the evidence in the literature to support anti-PD-1/PDL-1 application in the treatment of different lymphoid, myeloid, and virus-related hematological malignancies, and controversies related to PD-1/PD-L1 blocking in the management of ATLL patients.

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.

Chromosomal defects and survival in patients with adult T-cell leukemia/lymphoma after allogeneic HSCT

Adult T-cell leukemia/lymphoma (ATL) cells frequently exhibit chromosomal abnormalities, including numerical aberrations and structural defects. However, no studies have examined the correlation between these abnormalities and survival in patients with ATL after allogeneic HSCT (allo-HSCT). In this study, 300 patients with ATL (median age, 55 years; range, 24-74) who were registered in a Japanese nationwide registry database were analyzed. The majority (n = 183) had acute ATL. Specimens for chromosomal analysis were collected from bone marrow (n = 166), lymph nodes (n = 86), peripheral blood (n = 41), and other locations (n = 7). In survival analyses, breakpoints at 2q (hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.12-2.38; P = .012) and 5q (HR, 2.18; 95% CI, 1.25-3.80; P = .006) were significantly poor prognostic factors for overall survival (OS). In terms of ATL-related death, loss of chromosome 14 and breakpoints at 3p, 1q, 5q, and 6q were extracted as significantly poor prognostic factors. Moreover, complex karyotypes were associated with ATL-related death. This study of the survival impact of chromosomal abnormalities in patients with ATL after allo-HSCT demonstrated that several structural breakpoints were independent risk factors for OS and ATL-related death.

Outcomes of adult T-Cell leukemia/lymphoma with allogeneic stem cell transplantation: single-institution experience

Few publications exist concerning allogeneic hematopoietic cell transplant (alloHCT) outcomes in non-Japanese patients with HTLV-1-associated ATLL. We detail the patient and disease characteristics, transplant approach, and clinical outcomes in 17 patients with ATLL at our institution who underwent alloHCT. We report favorable outcomes, with 8/17 in ongoing remission, 2/17 with prolonged (>6 years) disease-free survival, and a low incidence of transplant-related mortality (2/17). These results validate the feasibility and efficacy of alloHCT in non-Japanese patients with ATLL.

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.

Cord blood transplantation with a reduced-intensity conditioning regimen using fludarabine and melphalan for adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell lymphoma with a poor prognosis when treated with chemotherapy alone; therefore, allogeneic stem cell transplantation is a consideration. We attempted cord blood transplantation (CBT) using a reduced-intensity conditioning regimen without total body irradiation (non-TBI-RIC) to allow for the best possible timing of transplantation and improve survival outcomes, particularly in older patients. Forty-eight patients (27 male, 21 female) underwent CBT using fludarabine (Flu) 125 mg/m² and melphalan (Mel) 140 mg/m² as pre-transplant conditioning. The median age was 32 years (range 44-72), and 21 patients were in complete remission (CR) at the time of CBT. The median duration to neutrophil engraftment (NE) was 19.5 days (range 15-50), with a cumulative incidence of NE of 86.7% at day 50 after CBT. The 1- and 3-year overall survival (OS) rates were 40.4% and 37.7%, respectively. The 3-year OS rate in CR patients was 60.8%, compared with 18.8% in non-CR patients. In ATLL patients, CBT with non-TBI-RIC using Flu/Mel is a promising treatment strategy.

Adult T-cell Leukemia-lymphoma with Primary Breast Involvement: A Case Report and Literature Review

Breast involvement of Adult T-cell leukemia-lymphoma (ATLL) is extremely rare, and the data on the characteristics are limited. We herein describe a 49-year-old woman who presented with skin involvement of ATLL. Positron emission tomography/computed tomography showed bilateral breast lesions. Although the patient once achieved a complete metabolic response, a relapse of her ATLL occurred. The patient received subsequent allogeneic hematopoietic stem cell transplantation (HSCT). To our knowledge, only four cases of ATLL with breast involvement have previously been reported, and the prognoses have generally been poor. Breast lesions of ATLL have aggressive features, and intensive systemic chemotherapy and HSCT are required to improve survival.

Increased incidence of adult T cell leukemia-lymphoma and peripheral T cell lymphoma-not otherwise specified with limited improvement in overall survival: a retrospective analysis using data from the population-based Osaka Cancer Registry

Peripheral T cell lymphomas (PTCL) are a heterogeneous group of non-Hodgkin lymphomas with poor outcomes. Adult T cell leukemia-lymphoma (ATL) and PTCL-not otherwise specified (PTCL-NOS)-are 2 common mature T cell lymphomas in Japan. Since it is unclear whether novel agents and treatment strategies incorporating hematopoietic cell transplantation have contributed to improved clinical outcomes in the real world, we performed a retrospective analysis using data from the population-based Osaka Cancer Registry. From 1977 to 2014, 1274 and 1143 patients were diagnosed with ATL or PTCL-NOS, respectively. Recently, the incidence of both diseases has gradually increased, and the age at diagnosis has risen. The 3-year overall survival (OS) rates in ATL patients were 12.0% in era 1 (1977-1999), 12.4% in era 2 (2000-2008), and 17.5% in era 3 (2009-2014) (P < 0.001). The 3-year OS rates in PTCL-NOS patients were 27.6% in era 1, 36.2% in era 2, and 35.0% in era 3 (P = 0.049). In conclusion, the incidences of ATL and PTCL-NOS have been increasing, particularly in elderly individuals. Clinical outcomes have improved in recent decades but are still unsatisfactory in both diseases. Thus, effective new treatment strategies incorporating novel agents are needed to further improve clinical outcomes in patients with ATL and PTCL-NOS.

Allogeneic Stem Cell Transplantation for Adult T-Cell Leukemia/Lymphoma-Romanian Experience

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive mature T-cell malignancy caused by the human T lymphoma virus I (HTLV-I) affecting 3–5% of HTLV-1 carriers and is usually diagnosed in endemic regions. Romania is a region with high prevalence of HTLV-1 infection and ATLL and with low median age at diagnosis for aggressive types. We performed a retrospective analysis of post-transplant outcome in the first Romanian patients with ATLL receiving hematopoietic stem cell allotransplant. The study population included eight patients (three males, five females), with median age of 39.5 (range 26–57), with acute (one case) and lymphoma type (seven cases) that received peripheral stem cells (PBSC) from matched related (MRD) and unrelated donors (MUD) after reduced intensity conditioning. Graft versus host disease (GVHD) developed in six patients. Relapse occurred in four cases (50%) at a median time of 5-months post-transplant. Six patients died: four cases with disease-related deaths and two patients with GVHD-related deaths. The median survival post-transplant was 19.5 months (range 2.3–44.2 months). The post-transplant survival at 1-year was 62.5%, at 2-years 50%, and at 3-years 37.5%. In our opinion allogeneic transplant improves outcome in aggressive type ATLL.

GVHD-free, relapse-free survival provides novel clues for optimizing allogeneic-HSCT for adult T-cell leukemia/lymphoma

The outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult T-cell leukemia/lymphoma (ATL) is still unsatisfactory. To illustrate the advantages and disadvantages of each donor source, we performed a nationwide retrospective study of graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) of patients with allo-HSCT-treated ATL. One-year GRFS did not significantly differ between patients who received related bone marrow transplantation (R-BMT; 26%, n = 117), related peripheral blood stem cell transplantation (R-PBSCT; 22%, n = 225), unrelated bone marrow transplantation (UR-BMT; 26%, n = 619), and cord blood transplantation (CBT; 21%, n = 359; p = 0.09). This was attributable to a low incidence of systemically-treated chronic GVHD after CBT (9% at 1 year) and reduced non-GVHD/relapse mortality after R-PBSCT (9% at 1 year). Among patients transplanted in complete remission (CR), 1-year overall survival after CBT (52%, n = 132) was not inferior to that after R-BMT (55%, n = 51), R-PBSCT (57%, n = 79), and UR-BMT (58%, n = 280; p = 0.15), and relapse rates were equivalent among the four sources (p = 0.19). Our results suggest that all donor sources are feasible for CR patients and that GRFS provides important clues toward optimizing allo-HSCT for ATL.

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.

Complete remission and proviral load negativization after allogeneic-SCT in a patient with Adult T-cell lymphoma: Case report

Adult T-cell lymphoma is an aggressive and poor prognosis HTLV1-associated lymphoma. There is no standard treatment, but it is known that intensive chemotherapy regimens are necessary, with or without concomitant antiretroviral therapy, plus consolidation with allogeneic stem cell transplantation. Our case report shows a favorable outcome after 2 cycles of chemotherapy and allogeneic stem cell transplantation without antiretroviral agents, achieving complete remission, and a negative proviral load.

Novel Treatments of Adult T Cell Leukemia Lymphoma

Adult T cell leukemia-lymphoma (ATL) is an aggressive malignancy secondary to chronic infection with the human T cell leukemia virus type I (HTLV-I) retrovirus. ATL carries a dismal prognosis. ATL classifies into four subtypes (acute, lymphoma, chronic, and smoldering) which display different clinical features, prognosis and response to therapy, hence requiring different clinical management. Smoldering and chronic subtypes respond well to antiretroviral therapy using the combination of zidovudine (AZT) and interferon-alpha (IFN) with a significant prolongation of survival. Conversely, the watch and wait strategy or chemotherapy for these indolent subtypes allies with a poor long-term outcome. Acute ATL is associated with chemo-resistance and dismal prognosis. Lymphoma subtypes respond better to intensive chemotherapy but survival remains poor. Allogeneic hematopoietic stem cell transplantation (HSCT) results in long-term survival in roughly one third of transplanted patients but only a small percentage of patients can make it to transplant. Overall, current treatments of aggressive ATL are not satisfactory. Prognosis of refractory or relapsed patients is dismal with some encouraging results when using lenalidomide or mogamulizumab. To overcome resistance and prevent relapse, preclinical or pilot clinical studies using targeted therapies such as arsenic/IFN, monoclonal antibodies, epigenetic therapies are promising but warrant further clinical investigation. Anti-ATL vaccines including Tax peptide-pulsed dendritic cells, induced Tax-specific CTL responses in ATL patients. Finally, based on the progress in understanding the pathophysiology of ATL, and the risk-adapted treatment approaches to different ATL subtypes, treatment strategies of ATL should take into account the host immune responses and the host microenvironment including HTLV-1 infected non-malignant cells. Herein, we will provide a summary of novel treatments of ATL in vitro, in vivo, and in early clinical trials.

Reversal of CYLD phosphorylation as a novel therapeutic approach for adult T-cell leukemia/lymphoma (ATLL)

Adult T-cell leukemia/lymphoma (ATLL) is a malignancy of mature T cells associated with chronic infection by human T-cell lymphotropic virus type-1 (HTLV-1). ATLL patients with aggressive subtypes have dismal outcomes. We demonstrate that ATLL cells co-opt an early checkpoint within the tumor necrosis factor receptor 1 (TNFR1) pathway, resulting in survival advantage. This early checkpoint revolves around an interaction between the deubiquitinase CYLD and its target RIPK1. The status of RIPK1 K63-ubiquitination determines cell fate by creating either a prosurvival signal (ubiquitinated RIPK1) or a death signal (deubiquitinated RIPK1). In primary ATLL samples and in cell line models, an increased baseline level of CYLD phosphorylation was observed. We therefore tested the hypothesis that this modification of CYLD, which has been reported to inhibit its deubiquitinating function, leads to increased RIPK1 ubiquitination and thus provides a prosurvival signal to ATLL cells. CYLD phosphorylation can be pharmacologically reversed by IKK inhibitors, specifically by TBK1/IKKε and IKKβ inhibitors (MRT67307 and TPCA). Both of the IKK sub-families can phosphorylate CYLD, and the combination of MRT67307 and TPCA have a marked effect in reducing CYLD phosphorylation and triggering cell death. ATLL cells overexpressing a kinase-inactive TBK1 (TBK1-K38A) demonstrate lower CYLD phosphorylation and subsequently reduced proliferation. IKK blockade reactivates CYLD, as evidenced by the reduction in RIPK1 ubiquitination, which leads to the association of RIPK1 with the death-inducing signaling complex (DISC) to trigger cell death. In the absence of CYLD, RIPK1 ubiquitination remains elevated following IKK blockade and it does not associate with the DISC. SMAC mimetics can similarly disrupt CYLD phosphorylation and lead to ATLL cell death through reduction of RIPK1 ubiquitination, which is CYLD dependent. These results identify CYLD as a crucial regulator of ATLL survival and point to its role as a potential novel target for pharmacologic modification in this disease.

Treatment with mogamulizumab or lenalidomide for relapsed adult T-cell leukemia/lymphoma after allogeneic hematopoietic stem cell transplantation: The Nagasaki transplant group experience

Mogamulizumab (Mog) and lenalidomide (Len) are new therapeutic candidates for relapsed adult T-cell leukemia/lymphoma after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the present study, we retrospectively analyzed 12 patients who received Mog or Len monotherapy for relapsed ATL after allo-HSCT. Eight and three patients received Mog and Len, respectively. The remaining patient received Mog for the first relapse and Len for the third relapse. A complete response was achieved by three and two patients who received Mog and Len, respectively, two and one of whom remained alive with a complete response for more than 20 months. In terms of adverse events, the emergence or progression of graft-versus-host disease was observed in three out of four patients treated with Len and in none of the patients treated with Mog. The development or progression of cytomegalovirus reactivation was detected in four out of eight patients treated with Mog and in none of those treated with Len. The present results suggest that Mog and Len would be promising treatment options for relapsed ATL after allo-HSCT and need to be selected based on adverse event profiles.

Updates in lymph node and skin pathology of adult T-cell leukemia/lymphoma, biomarkers, and beyond

Adult T-cell leukemia/lymphoma (ATLL) is a mature T-cell lymphoproliferative disorder associated with the human T lymphotropic virus (HTLV-1) infection. ATLL predominantly affects individuals within HTLV-1 endemic areas such as Japan, areas of Africa, South America, and the Caribbean. HTLV-1 preferentially infects CD4+ T-cells, and several genetic hits must occur before ATLL develops. ATLL is classically divided into four clinical variants based on manifestations of disease: acute, chronic, lymphomatous, and smouldering. As of 2019, a new subtype has been described: lymphoma type of ATL, extranodal primary cutaneous. In this review, emphasis will be taken to describe the common clinicopathologic manifestations of the disease, advances in biomarker discovery, mutational landscape and targeted therapeutic approaches to treat this highly aggressive and frequently lethal type of T-cell lymphoma.

A decision analysis comparing unrelated bone marrow transplantation and cord blood transplantation in patients with aggressive adult T-cell leukemia-lymphoma

Patients with aggressive adult T-cell leukemia-lymphoma (ATL) have dismal outcomes with intensive chemotherapy. Early up-front allogeneic hematopoietic stem cell transplantation (allo-HSCT) is generally recommended. However, the choice of stem cell source, i.e., unrelated bone marrow transplant (UBMT) or cord blood transplantation (CBT), when an HLA-matched related donor is unavailable remains controversial. Thus, we undertook a decision analysis to compare the outcomes of two therapeutic strategies: chemotherapy followed by up-front UBMT at 6 months, and chemotherapy followed by up-front CBT at 3 months. Patients were stratified into low-, intermediate-, and high-risk groups according to the modified ATL-prognostic index. The model simulated life expectancy (LE) and quality-adjusted LE (QALE). LE following up-front UBMT was higher than that following up-front CBT in the low-risk group (2.63 vs. 2.28 years), but was comparable in the intermediate- (2.06 vs. 2.01 years) and high-risk groups (1.25 vs. 1.30 years). The Monte Carlo simulation for LE and QALE in each risk group showed that there was significant uncertainty in all categories. In conclusion, up-front UBMT was superior to up-front CBT in the low-risk group, but the strategies were comparable in the intermediate- and high-risk groups.

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.

Is It Time to Revisit the Role of Allogeneic Transplantation in Lymphoma?

PURPOSE OF REVIEW

A multitude of new drug and cell therapy approvals for lymphoma has prompted questions about the role of allogeneic blood or marrow transplantation (allo-BMT). We sought to review the latest evidence examining the role of allo-BMT for lymphoma in this evolving landscape.

RECENT FINDINGS

Despite several new drug classes, there remains a large unmet need, particularly in hard to treat subtypes of lymphoma and for patients with relapsed/refractory disease. Allo-BMT can provide an opportunity for cure due to a potent graft vs lymphoma effect in high-risk relapse/refractory follicular lymphoma, mantle cell lymphoma, and aggressive T cell lymphomas. Chimeric antigen receptor T cell therapy and checkpoint blockers have improved outcomes for patients with relapsed /aggressive B cell lymphomas and Hodgkin lymphoma respectively; the role of allo-BMT consolidation in the treatment algorithm for responders to these therapies is an evolving topic. Expanded donor availability including haploidentical relatives has improved access to allo-BMT. Non-myeloablative conditioning regimens and post-transplant cyclophosphamide prophylaxis have improved early transplant-related morbidity and rates of graft versus host disease and translated into long-term survival for patients with lymphoid malignancies. Patient selection remains key, but allo-BMT remains the only modality able to deliver durable long-term remissions across different types of lymphoma.

Efficacy of Allogeneic Hematopoietic Cell Transplantation in Human T Cell Lymphotropic Virus Type 1-Associated Adult T Cell Leukemia/Lymphoma: Results of a Systematic Review/Meta-Analysis

Human T cell lymphotropic virus type 1 (HTLV1)-associated adult T cell leukemia/lymphoma (ATLL) is an aggressive malignant disorder. Intensive conventional chemotherapy regimens and autologous hematopoietic cell transplantation (HCT) have failed to improve outcomes in ATLL. Allogeneic HCT (allo-HCT) is commonly offered as front-line consolidation despite lack of randomized controlled trials. We performed a comprehensive search of the medical literature using PubMed/Medline, EMBASE, and Cochrane reviews on September 10, 2018. We extracted data on clinical outcomes related to benefits (complete response [CR], overall survival [OS], and progression-free survival [PFS]) and harms (relapse and nonrelapse mortality [NRM]), independently by 2 authors. Our search strategy identified a total of 801 references. Nineteen studies (n = 2446 patients) were included in the systematic review; however, only 18 studies (n = 1767 patients) were included in the meta-analysis. Reduced intensity conditioning regimens were more commonly prescribed (52%). Bone marrow (50%) and peripheral blood (40%) were more frequently used as stem cell source. The pooled post-allografting CR, OS, and PFS rates were 73% (95% confidence interval [CI], 57% to 87%), 40% (95% CI, 33% to 46%), and 37% (95% CI, 27% to 48%), respectively. Pooled relapse and NRM rates were 36% (95% CI, 28% to 43%) and 29% (95% CI, 21% to 37%), respectively. The heterogeneity among the included studies was generally high. These results support the use of allo-HCT as an effective treatment for patients with ATLL, yielding pooled OS rates of 40%, but relapse still occurs in over one-third of cases. Future studies should evaluate strategies to help reduce relapse in patients with ATLL undergoing allo-HCT.

Allogeneic Stem Cell Transplantation and Chimeric Antigen Receptor (CAR) T-Cell Therapy for the Treatment of Non-Hodgkin Lymphoma

Despite the myriad of available treatments, a substantial subset of patients with non-Hodgkin lymphoma are not able to achieve a prolonged disease-free interval with conventional chemotherapy or targeted agents. For these patients, hematopoietic stem cell transplantation remains an option for consolidative or curative treatment. Additionally, chimeric antigen receptor T-cell therapy has emerged for patients with relapsed/refractory B-cell lymphomas. Published studies vary widely in their selected approach to transplant and cellular therapies. This review summarizes available data related to allogeneic hematopoietic stem cell transplantation and chimeric antigen receptor T-cell therapy for the treatment of non-Hodgkin lymphomas.

VCAP-AMP-VECP as a preferable induction chemotherapy in transplant-eligible patients with aggressive adult T-cell leukemia-lymphoma: a propensity score analysis

A dose-intensified multi-agent chemotherapy regimen called VCAP-AMP-VECP was investigated in Japan as front-line therapy for patients with adult T-cell leukemia-lymphoma (ATL). Although a prospective randomized controlled study showed that VCAP-AMP-VECP was superior to CHOP, the trial was rather small and no subsequent studies confirmed the benefit of VCAP-AMP-VECP over CHOP. We conducted a retrospective analysis of transplant-eligible patients with ATL who received only VCAP-AMP-VECP or CHOP, incorporating inverse probability of treatment weighting (IPTW) using propensity scoring. Overall, 947 and 513 patients were treated with VCAP-AMP-VECP and CHOP, respectively. The median follow-up of surviving patients was 1006 days. The crude probabilities of 2-year overall survival (OS) for patients in the VCAP-AMP-VECP and CHOP groups were 31.2% and 24.6%, respectively (P < 0.001). Stratified by risk group according to the modified ATL-prognostic index score at diagnosis, the crude probabilities of 2-year OS in the VCAP-AMP-VECP and CHOP groups were 39.8 and 45.0% in the low-risk group (P = 0.69), 32.2 and 21.6% in the intermediate-risk group (P < 0.001), and 17.2 and 6.2% in the high-risk group (P = 0.005). Our current analysis suggests that VCAP-AMP-VECP regimen is a preferable front-line therapy in patients with aggressive ATL in intermediate- and high-risk groups.

Revised Adult T-Cell Leukemia-Lymphoma International Consensus Meeting Report

PURPOSE

Adult T-cell leukemia-lymphoma (ATL) is a distinct mature T-cell malignancy caused by chronic infection with human T-lymphotropic virus type 1 with diverse clinical features and prognosis. ATL remains a challenging disease as a result of its diverse clinical features, multidrug resistance of malignant cells, frequent large tumor burden, hypercalcemia, and/or frequent opportunistic infection. In 2009, we published a consensus report to define prognostic factors, clinical subclassifications, treatment strategies, and response criteria. The 2009 consensus report has become the standard reference for clinical trials in ATL and a guide for clinical management. Since the last consensus there has been progress in the understanding of the molecular pathophysiology of ATL and risk-adapted treatment approaches.

METHODS

Reflecting these advances, ATL researchers and clinicians joined together at the 18th International Conference on Human Retrovirology-Human T-Lymphotropic Virus and Related Retroviruses-in Tokyo, Japan, March, 2017, to review evidence for current clinical practice and to update the consensus with a new focus on the subtype classification of cutaneous ATL, CNS lesions in aggressive ATL, management of elderly or transplantation-ineligible patients, and treatment strategies that incorporate up-front allogeneic hematopoietic stem-cell transplantation and novel agents.

RESULTS

As a result of lower-quality clinical evidence, a best practice approach was adopted and consensus statements agreed on by coauthors (> 90% agreement).

CONCLUSION

This expert consensus highlights the need for additional clinical trials to develop novel standard therapies for the treatment of ATL.

A retrospective analysis of haplo-identical HLA-mismatch hematopoietic transplantation without posttransplantation cyclophosphamide for GVHD prophylaxis in patients with adult T-cell leukemia-lymphoma

Currently, allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only available curative modality for patients with adult T-cell leukemia-lymphoma (ATL). When used in conjunction with posttransplantation cyclophosphamide (PTCY) for graft-versus-host disease prophylaxis, allo-HCT from an HLA haplo-identical donor yields promising outcomes for many diseases other than ATL. However, appropriate comparisons with other donor sources, especially cord blood and conventional HLA haplo-identical donors, are needed to validate the safety and efficacy of this modality. In this study, we retrospectively evaluated the outcome of allo-HCT without PTCY in patients with ATL registered in the Japan Society for Hematopoietic Cell Transplantation TRUMP database between 1985 and 2015. During that period, 46 patients received allo-HCT without PTCY and survivors were followed for a median of 2316.5 days (range: 220-3884 days). Although the estimated 1- and 5-year overall survival rates of the entire cohort were 34.5% and 17.7%, respectively, the cumulative 1- and 5-year non-ATL mortality rates of 41.3% and 55.8%, respectively, were high. The results of our study will serve as a platform for discussions of the safety and efficacy of haplo-HCT for future clinical trials in patients with ATL.

Allogeneic hematopoietic stem cell transplantation for T-cell lymphomas

Mature T- and natural killer (NK)-cell neoplasms comprise a group of morphologically, immunophenotypically, molecularly, and clinically heterogeneous disorders with generally unfavorable outcome. Results of first-line chemotherapy are unsatisfactory for the most common T-cell lymphomas (peripheral T-cell lymphoma, not otherwise specified; angioimmunoblastic T-cell lymphoma; anaplastic large cell lymphomas; anaplastic lymphoma tyrosine kinase-negative) as well as for many other entities. High-dose therapy followed by autologous hematopoietic stem cell transplantation (HSCT) is widely recommended for consolidation after a complete or partial remission is achieved. However, about one-third of patients never reach transplantation because of early relapse or refractoriness. Targeted therapies have recently been developed; combinations with chemotherapy may improve outcomes, but long-term results from prospective studies are largely missing. In this situation, allogeneic HSCT remains a valuable treatment option inducing long-lived remissions in about 30% to 50% of patients with relapsed and refractory T-cell lymphoma able to proceed to transplantation. Results of allogeneic transplantation for consolidation in first remission are less defined and its indications remain controversial. With growing evidence that haploidentical HSCT also works in lymphoma, more patients can be brought to transplantation. Decreasing the morbidity and mortality of allogeneic transplantation is a continuous challenge. Integrating new drugs into transplant concepts and setting up prospective studies involving allogeneic transplantation remain unmet needs that warrant urgent study in a group of disorders in which classical chemotherapy and new drugs have generated results, which are far from optimal until today.

Mouse Models That Enhanced Our Understanding of Adult T Cell Leukemia

Adult T cell Leukemia (ATL) is an aggressive lymphoproliferative malignancy secondary to infection by the human T-cell leukemia virus type I (HTLV-I) and is associated with a dismal prognosis. ATL leukemogenesis remains enigmatic. In the era of precision medicine in oncology, mouse models offer one of the most efficient in vivo tools for the understanding of the disease biology and developing novel targeted therapies. This review provides an up-to-date and comprehensive account of mouse models developed in the context of ATL and HTLV-I infection. Murine ATL models include transgenic animals for the viral proteins Tax and HBZ, knock-outs for key cellular regulators, xenografts and humanized immune-deficient mice. The first two groups provide a key understanding of the role of viral and host genes in the development of ATL, as well as their relationship with the immunopathogenic processes. The third group represents a valuable platform to test new targeted therapies against ATL.

CMV70-3P miRNA contributes to the CMV mediated glioma stemness and represents a target for glioma experimental therapy

Glioblastoma multiforme (GBM) is a rapidly progressive brain tumor with a median survival of 15–19 months. Therapeutic resistance and recurrence of the disease is attributed to cancer stem cells (CSC). Here, we report that CMV70-3P miRNA encoded by CMV increases GBM CSC stemness. Inhibition of CMV70-3P expression using oligo inhibitors significantly attenuated the ability of primary glioma cells to proliferate and form neurospheres. At the molecular level, we show that CM70-3P increases expression of cellular SOX2. Collectively, these findings indicate that CMV70-3P is a potential regulator of CMV- mediated glioma progression and cancer stemness.

Adult T-cell leukemia/lymphoma in the Caribbean cohort is a distinct clinical entity with dismal response to conventional chemotherapy

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive disease caused by human T-cell lymphotropic virus type 1 that predominantly affects Japanese and Caribbean populations. Most studies have focused on Japanese cohorts. We conducted a retrospective analysis of 53 cases of ATLL who presented to our institution between 2003-2014. ATLL in the Caribbean population presents more often as the acute and lymphomatous subtypes, is associated with complex cytogenetics, and has a high rate of CNS involvement. The overall response rate to first-line therapies with anthracycline-based regimens was poor (32%), with a median survival of only 6.9 months. A complete or partial response to first-line regimens was associated with better survival. There was no difference in survival between patients who received chemotherapy alone versus chemotherapy with antiviral agents. Allogeneic transplantation was performed in five patients, two of whom achieved complete remission despite residual or refractory disease. Recipients of allogeneic transplantation had significantly improved overall survival compared to non-transplanted patients. This is the first analysis to describe ATLL pathological features, cytogenetics, and response to standard therapy and transplantation in the Caribbean cohort.

Clinical Practice Recommendations on Indication and Timing of Hematopoietic Cell Transplantation in Mature T Cell and NK/T Cell Lymphomas: An International Collaborative Effort on Behalf of the Guidelines Committee of the American Society for Blood and Marrow Transplantation

Recognizing the significant biological and clinical heterogeneity of mature T cell and natural killer (NK)/T cell lymphomas, the American Society for Blood and Marrow Transplantation invited experts to develop clinical practice recommendations related to the role of autologous hematopoietic cell transplantation (auto-HCT) and allogeneic HCT (allo-HCT) for specific histological subtypes. We used the GRADE methodology to aid in moving from evidence to decision making and ultimately to generating final recommendations. Auto-HCT in front-line consolidation is recommended in peripheral T cell lymphoma not otherwise specified (PTCL-NOS), angioimmunoblastic T cell lymphoma (AITL), anaplastic large cell lymphoma-anaplastic lymphoma kinase (ALCL-ALK)-negative, NK/T cell (disseminated), enteropathy-associated T cell lymphoma (EATL), and hepatosplenic lymphomas. Auto-HCT in relapsed-sensitive disease is recommended for NK/T cell (localized and disseminated), EATL, subcutaneous panniculitis-like T cell, and ALCL-ALK-positive lymphomas. Auto-HCT is also recommended for PTCL-NOS, AITL, and ALCL-ALK-negative lymphomas if not performed as front-line therapy. Auto-HCT in refractory (primary or relapsed) disease is not recommended for any of the histological subtypes discussed. Allo-HCT in front-line consolidation is recommended for NK/T cell (disseminated), adult T cell leukemia/lymphoma (ATLL; acute and lymphoma type), and hepatosplenic lymphomas. Allo-HCT for relapsed-sensitive disease is recommended for PTCL-NOS, AITL, ALCL-ALK-negative, ALCL-ALK-positive, NK/T cell (localized and disseminated), ATLL (acute, lymphoma type, smoldering/chronic), mycosis fungoides/Sezary syndrome (advanced stage IIB-IVB or tumor stage/extracutaneous), EATL, subcutaneous panniculitis-like T cell, and hepatosplenic lymphoma. Allo-HCT in refractory (primary or relapsed refractory) disease is recommended for any aforementioned histological subtypes. Emerging novel therapies will likely be incorporated into the pretransplantation, peritransplantation, and post-transplantation algorithms (auto-HCT or allo-HCT) with the goals of optimizing efficacy and improving outcomes. We acknowledge that there are unique clinical scenarios not covered by these recommendations that may require individualized decisions.

Treatment advances and prognosis for patients with adult T-cell leukemia-lymphoma

A classification for adult T-cell leukemia-lymphoma (ATL) based on clinical features was proposed in 1991: acute, lymphoma, chronic, and smoldering types, and their median survival times (MSTs) were reported to be 6.2, 10.2, 24.3 months, and not reached, respectively. Several new therapies for ATL have since been developed, i.e. dose-intensity multi-agent chemotherapies, allogeneic hematopoietic stem cell transplantation (allo-HSCT), monoclonal antibodies, and anti-viral therapy. The monoclonal antibody to CCR4, mogamulizumab, clearly improved response rates in patients with treatment-naïve and relapsed aggressive ATL, and has the potential to provide a survival advantage. The outcomes of allo-HSCT have been reported since the early 2000s. High treatment-related mortality was initially the crucial issue associated with this treatment approach; however, reduced intensity conditioning regimens have decreased the risk of treatment-related mortality. The introduction of allo- HSCT has had a positive impact on the prognosis of and potential curability with treatments for ATL. A meta-analysis of a treatment with interferon-α and zidovudine (IFN/AZT) revealed a survival benefit in patients with the leukemic subtype. A phase 3 study comparing IFN/AZT with watchful waiting in patients with indolent ATL is ongoing in Japan. Several clinical trials on novel agents are currently being conducted, such as the histone deacetylase inhibitors, alemtuzumab, brentuximab vedotin, nivolumab, and an EZH1/2 dual inhibitor.