Aggressive Adult T-cell Leukemia/lymphoma Research Articles

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.

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.

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.

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.

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for ATL with HTLV-1 Antibody-Positive Donors.

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only available curative treatment option for patients with aggressive adult T cell leukemia-lymphoma (ATL). Donor human T cell leukemia virus (HTLV) 1 seropositivity is a critical concern when choosing relative donors, as they are not usually recommended due solely to the occurrence of donor-derived ATL. A previous report suggested that allo-HCT with an HTLV-1-seropositive donor increased ATL-related mortality. We updated the risk assessment for choosing an HTLV-1-seropositive allo-HCT donor for ATL. Our current registry data, which include larger numbers of HTLV-1-seropositive donors and longer observation periods, revealed no significant difference in overall survival (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.70-1.24; P=.61) or cumulative incidence of either ATL-related (HR, 0.96; 95% CI, 0.64 to 1.45; P=.80) or non-ATL-related mortality (HR, 0.91; 95% CI, 0.61 to 1.37; P=.66). Similarly, when considering only patients with ATL in complete remission, there was no significant difference in overall survival (HR, 1.02; 95% CI, 0.70 to 1.49; P=.91) or cumulative incidence of either ATL-related (HR, 1.20; 95% CI, 0.66 to 2.20; P=0.54) or non-ATL-related mortality (HR, 0.86; 95% CI, 0.52-1.42; P=.66). These data indicate that selecting HTLV-1-seropositive donors might not be contraindicated for patients with ATL receiving allo-HCT if alternative donors are unavailable. Further risk assessment remains to be performed.

Identifying a Simple Clinical Prognostic Model for Aggressive Adult T-Cell Leukemia/Lymphoma in Latin American Population and Its Validation: A Large International Study of the Latin America Working Group for Lymphomas (GELL)

Identifying a Simple Clinical Prognostic Model for Aggressive Adult T-Cell Leukemia/Lymphoma in Latin American Population and Its Validation: A Large International Study of the Latin America Working Group for Lymphomas (GELL)

Improved Overall Survival Among Newly Diagnosed Aggressive Adult T-Cell Leukemia/Lymphoma Patients Treated with Mogamulizumab Plus EPOCH Compared to Mogamulizumab Plus Vcap-AMP-Vecp

Introduction: Adult T-cell leukemia/lymphoma (ATLL) is a rare and quite refractory peripheral T-cell lymphoma. The human T-lymphotropic virus type 1 (HTLV-1) retrovirus causes ATLL. Tax protein produced by HTLV-1 has oncogenic activities, and its peptides can be recognized as tumor antigens by the host immune system. Therefore, some immunological approaches to treat ATLL are effective. Mogamulizumab (Moga), an anti-CCR4 monoclonal antibody, and lenalidomide, an immunomodulator, have been recently approved for newly diagnosed and/or relapsed/refractory aggressive ATLL in Japan. However, to date, satisfactory treatment results have not been obtained with these drugs. Before approval of Moga and lenalidomide, VCAP-AMP-VECP (mLSG15) therapy was one of the standard combination chemotherapies for aggressive ATLL. A randomized phase II study comparing Moga plus mLSG15 and mLSG15 alone showed a higher %CR in Moga plus mLSG15 arm but no significant difference in overall survival (OS) between the two arms. In this study, we compared the outcomes of Moga plus EPOCH with those of Moga plus mLSG15. Methods: Aggressive ATLL patients, who were ineligible for hematopoietic stem cell transplantation (HSCT) and were newly diagnosed after June 2000 in our hospital, were retrospectively analyzed. Results: Table 1 summarizes the patient characteristics. Twenty-two patients were treated with Moga plus EPOCH, and 16 were treated with Moga plus mLSG15. There was no significant difference in gender and disease subtype between the groups. Moga-induced skin disorders, such as rash and erythema, were observed in 14 (64%) patients treated with Moga plus EPOCH group and 9 (56%) patients treated within Moga plus mLSG15; the difference was not significant. Figure 1 shows OS of both groups. There was no significant difference (P=0.3092), but a 30% risk reduction was observed in the Moga plus EPOCH group (hazard ratio [HR]: 0.6859, 95% confidence interval [CI]: 0.3165−1.430), though patients treated with Moga plus EPOCH were significantly older than those treated with Moga plus mLSG15 (Table 1). Figure 2 shows OS of patients with and without Moga-induced skin disorders in both groups. The OS of patients with skin disorders was significantly greater than that of those without skin disorders (P<0.0001, HR: 0.2653, 95% CI: 0.05879−0.3628), as previously reported. Elevation of the Tax-specific cytotoxic T-lymphocytes (CTL) percentage was observed after occurrences of skin disorders in some patients. Representative data are shown in Figure 3. These data suggest that the combination chemotherapy regimen might be irrelevant for patients with Moga-induced skin disorders. Next, the OS of the Moga plus EPOCH group was compared with that of those treated with chemotherapy alone, such as mLSG15 and the CHOP-like regimen, as the historical control (Table 2). There was no statistical difference between the groups, but a 16% risk reduction was observed in the Moga plus EPOCH group (P=0.5885, HR: 0.8401, 95% CI: 0.4491−1.568) (Figure 4), though those treated with Moga plus EPOCH were significantly older than those treated with chemotherapy alone (Table 2). A 36% risk reduction in OS was observed in patients with Moga-induced skin disorders compared to those treated with chemotherapy alone (Figure 5). Conclusion: Improved OS was observed more frequently in the Moga plus EPOCH group than in the Moga plus mLSG15 group. However, to date, Moga plus chemotherapy has not shown a significant impact on OS for newly diagnosed aggressive ATLL patients in non-HSCT settings, except for patients with Moga-induced skin disorders. Elevation of the Tax-specific CTL percentage was observed in some patients with Moga-induced skin disorders. We previously reported in the 2014 ASH annual meeting that several aggressive ATLL patients, who obtained long-time survival using chemotherapy alone, had maintained Tax-specific CTLs for long periods. Therefore, it might be necessary to induce, up-regulate, and maintain ATLL-specific CTLs to obtain long-time survival. Moga is useful, but insufficient, for inducing such CTLs by suppressing regulatory T-cells. No effective method is available to activate an ATLL-specific cellular immune response. Further studies are urgently needed to establish effective methods for attaining ATLL-specific CTLs. Disclosures No relevant conflicts of interest to declare.

Somatic Mutations and Loss of Heterozygosity of HLA Genes Are Frequently Occurred and Tightly Associated with Poor Prognosis in Adult T Cell Leukemia-Lymphoma

Introduction: Adult T cell leukemia-lymphoma (ATL) is clinically divided into aggressive (acute and lymphoma) and indolent (chronic and smoldering) subtypes. Recent studies revealed that ATL has a wide variety of gene alternations (Nat Genet. 2015; 47:1304, Nature. 2016; 534:402). Consistent with the notion that human leukocyte antigen (HLA) play a critical role for immune response, reduced expression of HLA has been shown to associate with poor prognosis in various types of malignancies (Oncogene. 2008; 27:5869). However, it is extremely difficult to assess the impact of somatic mutations of HLA genes in cancer cells because of its highly polymorphic nature. Taking advantage of computational tools using whole-exome sequencing data, somatic mutations of HLA class I genes were previously reported in about 3% of various types of cancers (Nat Biotechnol. 2015; 33:1152). To date, HLA typing has been performed through partial sequencing data of polymorphic exons, resulting in the loss of critical information on the entire region of HLA genes. In this context, using a next generation sequence (NGS)-based HLA DNA typing method, we analyzed the entire region of HLA genes in ATL cells and its impact on clinical outcomes. Methods: The present study was approved by the Investigational Review Board of University of the Ryukyus and Tokai University. Peripheral blood mononuclear cells collected from 25 ATL patients (Pts) (20 with acute type and 5 with chronic type) were analyzed. Cell adhesion molecular 1 (CADM1)-positive ATL cells and CADM1-negative non-ATL cells were separated by a magnetic-activated cell-sorting protocol, and genomic DNAs in each fraction were distinctively extracted. The PCR products of the eight HLA loci (HLA-A, -B, -C, -DRB1, -DQA1, -DQB1, -DPA1 and -DPB1) were obtained using the previously designed long ranged PCR primers (Tissue Antigens. 2012; 80:305) that cover the entire HLA gene sequences from the enhancer-promoter region to the 3'UTR region. The full-length level HLA genotypes were determined by mapping of sequence reads obtained by the Ion Torrent system to HLA allele reference sequences in the international ImMunoGeneTics project (IMGT)-HLA database. Somatic mutations and loss of heterozygosity (LOH) generated in ATL cells were identified by detail comparison of sequence data between the ATL and non-ATL cells. Survival curves were estimated using the Kaplan-Meier method and compared by the log-rank test. Results: We found a total of 20 somatic mutations in ATL cells among 9 Pts, including 15 single nucleotide variations (SNVs) and 5 insertions/deletions (indels) (Table 1). Of the 15 SNVs, 3 were nonsense mutations in exon 2/3 of HLA-A/B, 7 were nonsynonymous mutations in exon 1/4/5 of HLA-A/B/C, and 2 were mutations at splice sites in intron 2 of HLA-B/C. The mutations of splice sites in intron 2 and all the 5 indels caused frameshift generating premature stop codons. In contrast to the exons, there were only 3 mutations found in introns. Of 8 Pts harboring LOH, two Pts showed LOH in HLA-A gene, 4 Pts in HLA-A, -C, and -B genes, one Pt in HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 genes, and one Pt in all the HLA-genes from HLA-A to HLA-DPB1. All the somatic mutations altering the structure of the HLA proteins (St-mt) and/or LOH were found in Pts with acute type ATL, while no St-mt or LOH were detected in Pts with chronic type ATL. Pts with St-mt/LOH (n = 9) significantly worsened in 3 years overall survival rate as compared to that in Pts without St-mt/LOH (n = 16) (11 % vs. 32 %, P = 0.016) (Fig. 1A). Among Pts with acute type ATL, Pts with St-mutations/LOH (n = 9) also showed a trend to worsen in the survival rate as compared to those in Pts without St-mutation /LOH (n = 11) (11 % vs. 30 %, P=0.064) (Fig. 1B). Conclusion: NGS-based HLA gene analyses at full-length level revealed that St-mt/LOH were frequently occurred predominantly in HLA class I loci in tumor cells from Pts with aggressive ATL. Importantly, St-mt/LOH in HLA genes were associated with aggressive phenotypes and poor prognosis, suggesting the possibility that ATL cells would develop immune escape mechanisms through a variety of acquired abnormalities in HLA gene. Since allogeneic stem cell transplantation is an essential therapeutic option for aggressive ATL, comprehensive knowledges on HLA gene abnormalities provide considerable advantage to optimize therapeutic modalities. Disclosures Fukushima: Daiichi-Sankyo: Research Funding.

Proteomic Profiling of HTLV-1 Carriers and ATL Patients Reveal TNFR2 As a Novel Diagnostic and Chemosensitivity Biomarker for ATL

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell malignancy associated with the human T-cell leukemia virus type I (HTLV-1). Classification of ATL into clinical subtypes acute, lymphoma, chronic and smoldering types was proposed based on prognostic factors, clinical features and natural history of the disease. Although HTLV-1 infection alone is not sufficient to cause ATL and only about 5% of HTLV-1 carriers progress to ATL, the prognosis is generally poor especially for patients with aggressive ATL (i.e., acute, lymphoma or unfavorable chronic types), with a median survival time at around 1 year, even after chemotherapy. Currently, biomarkers to predict ATL onset and progression are limited, making early diagnosis and treatment for ATL challenging. To develop early diagnostic biomarkers for ATL, we performed, for the first time, an extensive proteomic profiling of HTLV-1 carriers and ATL patients as a foundation for establishing a blood-based biomarker panel for ATL. Expression levels of 1305 plasma proteins in HTLV-1 carriers (n=40), untreated ATL patients (n=40, 28 acute; 4 lymphoma; 5 chronic; 3 smoldering), and remission status (n=5) were measured by SOMAscan assay (SomaLogic Inc, Boulder, CO). ATL diagnosis was based on criteria proposed by the Japan Clinical Oncology Group (JCOG) and identification of monoclonal integration of HTLV-1 proviral DNA using Southern blot hybridization method. Deregulated proteins in HTLV-1 versus ATL versus remission states were ranked by significance (Welch's t-test) and discrimination capacity (area under the curve [AUC]). In addition, machine learning algorithms were used to set discrimination boundaries for HTLV-1, ATL, and remission states using some of the top deregulated proteins. Statistical analyses were performed using Python 3.6.2 software. To elucidate on ATL pathogenesis, we further analyzed our proteomic data using Gene Set Enrichment Analysis (GSEA 3.0 hallmarks, curated gene sets) and Gene Ontology (GO Panther Pathways) and determined pathway deregulation among disease states as well as among ATL subtypes. Overrepresented pathways in ATL versus HTLV-1 included inflammation mediated by cytokine and chemokine signaling, angiogenesis, notch signaling, and IL6/JAK/STAT3, among others. Among a total of 176 proteins which were categorized as extremely significant (p<0.00001) with AUC scores ranging from 0.90-0.99, we further confirmed plasma protein concentrations of CD223 (LAG3) (n=40, 2 healthy individuals; 8 HTLV-1 carriers; 10 acute; 8 lymphoma; 6 chronic; 6 smoldering), CD30 (TNFRSF8), TIM-3 (HAVCR2) (n=40, 2 healthy individuals; 8 HTLV-1 carriers; 12 acute; 6 lymphoma, 6 chronic; 6 smoldering), and TNFR2 (TNFRSF1B) (n=79, 5 healthy individuals; 16 HTLV-1 carriers; 26 acute; 9 lymphoma; 11 chronic; 9 smoldering), through ELISA. We discovered significantly higher CD30 and TIM-3 levels in acute ATL versus HTLV-1 carriers (p<0.05) and remarkably high TNFR2 levels among aggressive ATL patients, acute (p<0.001) and lymphoma types (p<0.01) versus HTLV-1 carriers. In addition, a significant decrease in TNFR2 levels among ATL patients who have achieved remission was also seen (p<0.001). These results indicate the potential value of TNFR2 not only as a diagnostic biomarker for ATL, but also for predicting response or failure to therapy. Furthermore, this study represents a novel proteomic approach in developing candidate biomarkers for ATL, by combining data from high-throughput SOMAmer technology, machine learning, proteomic pathway analysis, in addition to previously well-established techniques such as ELISA. Further investigation of TNFR2 and other potential biomarkers in this study need to be done in the near future. Disclosures Fukushima: Daiichi-Sankyo: Research Funding.

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.

Impact of pretransplant anti-CCR4 antibody administration on clinical outcomes in allogeneic hematopoietic stem cell transplantation

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-cell lymphoma caused by human T-cell lymphotropic virus type I. Patients with aggressive ATL exhibit poor outcomes, even with dose-dense intensive chemotherapy. Thus, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered in all patients eligible for transplant. However, patients with aggressive ATL often have chemo-refractoriness or experience early relapse during chemotherapy. Allo-HSCT is often ineffective in patients with active disease status. Mogamulizumab (Moga) was approved in 2012 in Japan as a potent treatment option for patients with relapsed or refractory ATL. However, there is a major concern that the use of Moga before allo-HSCT could increase the risk of post-transplant complications, such as graft-versus-host disease (GVHD), because Moga depletes regulatory T cells. Here, we would like to describe the possible effects of pre-transplant Moga on post-transplant complications, such as acute GVHD, and to discuss how Moga could be efficiently incorporated in the treatment regimen of patients with aggressive ATL to maximize the expected clinical benefit.

The In Vivo infected Clones Have Mixed Immunophenotype and Malignant Transformation Is Characterized By Dominant Growth of CD4+CCR4+CD26-CD7- Cells in Human T Lymphotropic Virus Type 1 Infection

Aggressive Adult T cell leukemia/lymphoma (ATL), a human T lymphotropic virus type 1 (HTLV-1) -associated disease, has a poor prognosis. There is an urgent need for effective prevention and treatment. Aggressive ATL develops in patients with non-malignant HTLV-1 (asymptomatic carriers (AC) and patients with HTLV-1 associated myelopathy (HAM)) over decades with evolution from high proviral load (PVL) and non-dominant clonal growth through emergence of dominant clones and indolent to aggressive ATL. A single dominant clone is a major contributor to HTLV-1 infection burden in ATL despite a polyclonal background whilst hundreds of small clones contribute relatively equally to infection burden in non-malignant HTLV-1 infection(1). CD4+CCR4+CD26-CD7- is the dominant immunophenotype of lymphocytes in patients with ATL (ATL cells) but infected cells with similar immunophenotype (‘ATL-like’ cells) are also present in patients with non-malignant HTLV-1 infection(2). We hypothesize that ‘ATL-like’ infected cells harbor: larger HTLV-1 infected clones detected in total PBMC and are more oligo-clonal compared to total PBMC in patients with high PVL non-malignant HTLV-1 infection and; only the dominant clone detected in total PBMC in patients with ATL. The aim is to study the relationship between clonality and immunophenotype in patients with high PVL non-malignant HTLV-1 infection and ATL.Clonality analysis was performed on total PBMC by ligation mediated PCR followed by high throughput sequencing (LMPCR-HTS) and on sorted CD4+CCR4+CD26-CD7- cells by LMPCR-HTS and T-cell receptor (TCR) sequencing in ACs (four and nine respectively), patients with HAM (four and nine respectively) and patients with ATL (four and nine respectively). Clonality analysis within CD4+CCR4+CD26-CD7- cells, similar to PBMC, showed hundreds of non-dominant clones (relative abundance of largest clone ≤ 25%) in 83% of patients with high PVL non-malignant HTLV-1 infection and a dominant clone (relative abundance of largest clone ≥ 25%) over a background of non-dominant clones in 17% and 100% of patients with non-malignant HTLV-1 infection and ATL respectively. CD4+CCR4+CD26-CD7- cells contributed a median of 95% of the largest PBMC clone in patients with ATL and a median of 23% of the largest PBMC clone in 63% of patients with non-malignant HTLV-1 infection. Cells which do not have ‘ATL-like’ immunophenotype (CD4+CCR4- and CD4+CCR4+CD26-CD7+) were also detected alongside CD4+CCR4+CD26-CD7- cells within individual clones in patients with non-malignant HTLV-1 infection as shown in figure 1. Three out of eighteen patients with high PVL non-malignant HTLV-1 infection had two or more dominant clones, one of which showed signs of overt ATL 12 months after the sample data. Clonality analysis in an patient with incident aggressive ATL showed presence of two dominant clones with two integrated provirus each 3 months prior to diagnosis and single dominant clone at presentation, remission and relapse as shown in figure 2. There was no significant difference in distribution of viral integration site by LMPCR-HTS or TCR repertoire in patients with non-malignant HTLV-1 infection and ATL.In summary, ‘ATL-like’ cells are derived from relatively small non-dominant clones in the majority of patient with high PVL non-malignant HTLV-1 infection and from a dominant clone over a non-dominant background in patients with ATL. The dominant clone in patients with ATL was comprised almost universally of ‘ATL-like’ cells whilst the large PBMC clones in patients with non-malignant HTLV-1 infection had cells with a mixed immunophenotype including ‘ATL-like’ and non- ‘ATL-like’ cells. Oligoclonal proliferation of ‘ATL-like’ cells precedes monoclonal proliferation at clinical presentation of ATL. Clonality analysis in patient with high PVL non-malignant HTLV-1 infection might help in further prognostication in malignant risk.Cook LB, Melamed A, Niederer H, Valganon M, Laydon D, Foroni L, et al. The role of HTLV-1 clonality, proviral structure, and genomic integration site in adult T-cell leukemia/lymphoma. Blood. 2014;123(25):3925-31.Kagdi H, Demontis MA, Ramos JC, Taylor GP. Switching and loss of cellular cytokine producing capacity characterize in vivo viral infection and malignant transformation in human T- lymphotropic virus type 1 infection. PLoS pathogens. 2018;14(2):e1006861. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Transcriptome and Somatic Mutation Associated with Non-Malignant Human T Lymphotropic Virus Type 1 Infection and Adult T-Cell Leukemia/Lymphoma

Aggressive Adult T-cell leukemia/lymphoma (ATL), a human T lymphotropic virus type 1 (HTLV-1) -associated disease, has a poor prognosis. There is an urgent need for effective prevention and treatment. A large number of genomic aberrations including hundreds of somatic mutations and copy number changes are typically observed in ATL tumours, with certain genes, PLCG1, PRKCB, CCR4, CARD11, STAT3, TP53, VAV1, TBL1XR1, NOTCH1, GATA3 and IRF4 mutated in over 10% of cases(1). CD4+CCR4+CD26-CD7- is the dominant immunophenotype of lymphocytes in patients with ATL (ATL cells) but infected cells with similar immunophenotype (‘ATL-like’ cells) are also present in patients with non-malignant HTLV-1 infection(2, 3). Aggressive ATL develops in patients with non-malignant HTLV-1 (asymptomatic carriers (AC) and patients with HTLV-1 associated myelopathy (HAM)) over decades with evolution from high proviral load (PVL) and non-dominant clonal growth through emergence of dominant clones and indolent to aggressive ATL. HTLV-1 infected clones have been shown to have cells with mixed immunophenotype. The aim was to investigate specific genomic aberration associated with non-malignant HTLV-1 infection, dominant clonal growth and ATL.RNA sequencing followed by differential gene expression and mutational analysis of HTLV-1 and human genes was performed on sorted CD4+CCR4+CD26-CD7- cells from nine patients with ATL (four with indolent, four with aggressive ATL and one with indolent to aggressive transformation; ATL cells); and 18 patients with high PVL non-malignant HTLV-1 infection (three with dominant clones and 15 with non-dominant clones, ‘ATL-like’ infected cells). Seven antisense transcript of HTLV-1 genome was detected. A spliced antisense transcript spanning the whole HTLV-1 genome was detected in all samples whilst two novel transcripts were detected in > 2 samples. There was no significant difference in viral transcriptome expression between ATL and ‘ATL-like’ cells. A total of 13637 including 7952 well annotated human genes were detected within which 400 genes were significantly differentially expressed ( > 2 fold change and false discover rate < 0.1) between ATL and ‘ATL-like’ cells as shown in figure 1. Small nuclear RNA and endothelial cancer associated genes were upregulated in patients with ATL whilst T-cell, inflammatory, apoptosis and proliferation related genes were upregulated in patients with non-malignant HTLV-1 infection respectively. Principle component analysis did not showed any significant cluster but hierarchical analysis using differentially expressed genes showed clustering of ATL cells from patient with aggressive ATL, indolent ATL and ‘ATL-like’ cells from patients with non-malignant HTLV-1 infection (AC and HAM) of ATL as shown in figure 2. One out of three patient with high PVL non-malignant HTLV-1 infection and dominant clones (HKU) clustered with ATL and this patient progressed to ATL 12 months from sample data. Hallmark pathway analysis showed upregulation cluster in ‘ATL-like’ cells with only metabolism associated pathways clustered in ATL cells as shown in table 1. Expression of all recurrently mutated genes was detected and mutation analysis is currently underway.In summary, there is a major overlap of infected cell transcriptome in patient with non-malignant HTLV-1 infection and ATL. ATL cells have downregulation of T-cell, inflammatory, apoptosis and proliferation related genes compared to ‘ATL-like’ infected cells whilst upregulation of small nuclear RNAs. Transcriptome analysis in patient with high PVL non-malignant HTLV-1 infection might help in further prognostication in malignant risk.Kataoka K, Nagata Y, Kitanaka A, Shiraishi Y, Shimamura T, Yasunaga J, et al. Integrated molecular analysis of adult T cell leukemia/lymphoma. Nature genetics. 2015;47(11):1304-15.Kagdi H, Demontis MA, Ramos JC, Taylor GP. Switching and loss of cellular cytokine producing capacity characterize in vivo viral infection and malignant transformation in human T- lymphotropic virus type 1 infection. PLoS pathogens. 2018;14(2):e1006861.Kagdi HH, Demontis MA, Fields PA, Ramos JC, Bangham CR, Taylor GP. Risk stratification of adult T-cell leukemia/lymphoma using immunophenotyping. Cancer medicine. 2017;6(1):298-309. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Possibility of a Risk-Adapted Treatment Strategy for Untreated Aggressive Adult T-Cell Leukemia-Lymphoma (ATL) Based on the ATL Prognostic Index: A Supplementary Analysis of the JCOG9801 Study

Possibility of a Risk-Adapted Treatment Strategy for Untreated Aggressive Adult T-Cell Leukemia-Lymphoma (ATL) Based on the ATL Prognostic Index: A Supplementary Analysis of the JCOG9801 Study

Tax-Targeting Dendritic Cell Therapy for ATL: A Phase Ia/Ib Clinical Study

Background: Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive peripheral T-cell neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). Although most patients respond to initial therapy, relapse is inevitable and the overall prognosis is dismal. Therefore, we developed a novel immune therapy consisting of autologous dendritic cells (DC) pulsed with Tax peptides (ATL-DC-101) to prevent relapse. The used peptides are corresponding to the major epitopes of HTLV-1 Tax-specific cytotoxic T lymphocytes (CTLs) that potentially act as anti-ATL effectors. Mogamulizumab is an anti-CCR4 antibody, which binds to ATL cells and regulatory T cells. A preceding pilot study suggested the safety of ATL-DC-101 monotherapy, and then we conducted a phase Ia/Ib study to investigate safety and efficacy of ATL-DC-101 combined with mogamulizumab.Methods: ATL patients pretreated and stable for at least 4 weeks were enrolled. Peripheral blood mononuclear cells were obtained by apheresis and differentiated into DC, which was pulsed with Tax-peptides. The study consisted of 2 cohorts, i.e., Ia and Ib phase, in which patients were assigned ATL-DC-101 monotherapy and ATL-DC-101 combined with mogamulizumab, respectively. The protocol consisted of three subcutaneous injections of ATL-DC-101 at 2-week intervals. Mogamulizumab was administered once before ATL-DC-101 in Ib phase. The primary endpoint of the study was to evaluate safety and feasibility of ATL-DC-101. The secondary endpoints were anti-tumor effects, progression-free survival (PFS), overall survival (OS), and time to next treatment, estimated by Kaplan-Meier method. The safety and disease status were accessed at day 56 and followed until 2 years.Results: Six aggressive ATL patients who were in stable condition by previous therapies were enrolled in this study from 2015 to 2016. Frequent DC- related toxicities were mild injection site reaction (n=5, 83.3%), decreased WBC count (n=3, 50%), and liver damage (n=2, 33.3%), all of which were grade 1 or 2. Notably, 2 patients (1 in each cohort) with partial response (PR) after chemotherapy were converted into complete response (CR) after ATL-DC-101. The 2-year PFS and OS were both 83.3%. All three patients who received ATL-DC-101 monotherapy (Ia) maintained CR for more than two years. Although one patient in phase Ib developed progressive disease after one year, the other two patients remained in CR. Interestingly ATL cells in a relapsed case harbored deletion of Tax gene, which resulted in the loss of the target peptide presentation. After a median follow-up of 29 months, 5/6 patients are alive without any additional chemotherapy after ATL-DC-101.Conclusions: ATL-DC-101 was well tolerated and successfully maintained CR more than 2 years in 5/6 patients irrespective of additional mogamulizumab, indicating that this therapy could be a safe and effective long-lasting maintenance therapy even for elderly ATL patients. Currently, we are preparing Phase II trial to confirm anti-tumor effects of ATL-DC-101 monotherapy. DisclosuresShiratsuchi:Kyowa Hakko Kirin Co.Ltd: Research Funding; Chugai Pharmaceutical Co.Ltd: Research Funding; Daiichi Sankyo Co.Ltd: Research Funding. Fukuda:Chugai Pharmaceutical: Speakers Bureau. Ishida:Kyowa Hakko Kirin Co.Ltd: Honoraria, Research Funding; Celgene K.K: Honoraria, Research Funding; Bayer AG: Research Funding; Mundiparma K: Honoraria. Akashi:Ono Pharmaceutical: Research Funding; MSD: Research Funding; Taiho Pharmaceutical: Research Funding; sanofi: Research Funding; Celgene: Research Funding, Speakers Bureau; Eli Lilly Japan: Research Funding; Novartis pharma: Research Funding; Kyowa Hakko Kirin: Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding, Speakers Bureau; Otsuka Pharmaceutical: Research Funding; Eisai: Research Funding; Pfizer: Research Funding; Astellas Pharma: Research Funding; Asahi-kasei: Research Funding; Chugai Pharma: Research Funding. Matsuoka:Bristol Myers Squibb: Research Funding. Suehiro:Kyowa Hakko Kirin: Research Funding; Ono Pharmaceutical: Research Funding; Chugai Pharmaceutical: Research Funding; Takeda Pharmaceutical: Research Funding.

Mutational Intratumor Heterogeneity is a Complex and Early Event in the Development of Adult T-cell Leukemia/Lymphoma

The clonal architecture of tumors plays a vital role in their pathogenesis and invasiveness; however, it is not yet clear how this clonality contributes to different malignancies. In this study we sought to address mutational intratumor heterogeneity (ITH) in adult T-cell leukemia/lymphoma (ATL). ATL is a malignancy with an incompletely understood molecular pathogenesis caused by infection with human T-cell leukemia virus type-1 (HTLV-1). To determine the clonal structure through tumor genetic diversity profiles, we investigated 142 whole-exome sequencing data of tumor and matched normal samples from 71 ATL patients. Based on SciClone analysis, the ATL samples showed a wide spectrum of modes over clonal/subclonal frequencies ranging from one to nine clusters. The average number of clusters was six across samples, but the number of clusters differed among different samples. Of these ATL samples, 94% had more than two clusters. Aggressive ATL cases had slightly more clonal clusters than indolent types, indicating the presence of ITH during earlier stages of disease. The known significantly mutated genes in ATL were frequently clustered together and possibly coexisted in the same clone. IRF4, CCR4, TP53, and PLCG1 mutations were almost clustered in subclones with a moderate variant allele frequency (VAF), whereas HLA-B, CARD11, and NOTCH1 mutations were clustered in subclones with lower VAFs. Taken together, these results show that ATL displays a high degree of ITH and a complex subclonal structure. Our findings suggest that clonal/subclonal architecture might be a useful measure for prognostic purposes and personalized assessment of the therapeutic response.

Evaluation of two prognostic indices for adult T-cell leukemia/lymphoma in the subtropical endemic area, Okinawa, Japan.

Aggressive adult T‐cell leukemia/lymphoma (ATL) has an extremely poor prognosis and is hyperendemic in Okinawa, Japan. This study evaluated two prognostic indices (PIs) for aggressive ATL, the ATL‐PI and Japan Clinical Oncology Group (JCOG)‐PI, in a cohort from Okinawa. The PIs were originally developed using two different Japanese cohorts that included few patients from Okinawa. The endpoint was overall survival (OS). Multivariable Cox regression analyses in the cohort of 433 patients revealed that all seven factors for calculating each PI were statistically significant prognostic predictors. Three‐year OS rates for ATL‐PI were 35.9% (low‐risk, n = 66), 10.4% (intermediate‐risk, n = 256), and 1.6% (high‐risk, n = 111), and those for JCOG‐PI were 22.4% (moderate‐risk, n = 176) and 5.3% (high‐risk, n = 257). The JCOG‐PI moderate‐risk group included both the ATL‐PI low‐ and intermediate‐risk groups. ATL‐PI more clearly identified the low‐risk patient subgroup than JCOG‐PI. To evaluate the external validity of the two PIs, we also assessed prognostic discriminability among 159 patients who loosely met the eligibility criteria of a previous clinical trial. Three‐year OS rates for ATL‐PI were 34.5% (low‐risk, n = 42), 9.2% (intermediate‐risk, n = 109), and 12.5% (high‐risk, n = 8). Those for JCOG‐PI were 22.4% (moderate‐risk, n = 95) and 7.6% (high‐risk, n = 64). The low‐risk ATL‐PI group had a better prognosis than the JCOG‐PI moderate‐risk group, suggesting that ATL‐PI would be more useful than JCOG‐PI for establishing and examining novel treatment strategies for ATL patients with a better prognosis. In addition, strongyloidiasis, previously suggested to be associated with ATL‐related deaths in Okinawa, was not a prognostic factor in this study.

Pre- and posttransplant use of mogamulizumab in patients with aggressive adult T-cell leukemia-lymphoma: A statement from key opinion leaders in Japan

Pre- and posttransplant use of mogamulizumab in patients with aggressive adult T-cell leukemia-lymphoma: A statement from key opinion leaders in Japan

Genetic analysis and its clinical implication in adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell neoplasm with a dismal prognosis. This disease is caused by human T-cell leukemia virus type-1 (HTLV-1) retrovirus. Not only viral proteins, such as Tax and HBZ, but also additional genetic and epigenetic aberrations, including gain-of-function alterations in the components of T-cell receptor/NF-κB pathway or deteriorating alterations responsible for immune surveillance, are essential for ATL development and progression. Furthermore, recent investigation has demonstrated the effects of genetic and epigenetic alterations prevalently identified in ATL on the disease phenotype and its clinical outcomes. Aggressive ATL is associated with an increased burden of genetic and epigenetic abnormalities. Higher frequencies of TP53 and IRF4 mutations and several copy number alterations, including PD-L1 amplifications and CDKN2A deletions, are more predominant in aggressive than indolent diseases. In contrast, STAT3 mutations are more frequent in indolent ATL. Several genetic alterations, such as PD-L1 amplification, can predict the clinical outcomes independent of established clinical factors. Therefore, ATL subtypes can further be subdivided into genetically distinct subgroups with different prognoses. The genetic profiling of ATL cases has revealed its molecular pathology and should contribute to improved prognostication and management of patients with ATL.

Role of anti-CCR4 antibody in the treatment of transplant-eligible patients with aggressive adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell lymphoma caused by the human T-cell lymphotropic virus type I. Patients with aggressive ATL show dismal prognoses, even with intensive dose-dense chemotherapy. Such patients often show chemo-refractoriness. Mogamulizumab (Moga) is a potent treatment option for patients with relapsed or refractory ATL. However, use of Moga before allo-HSCT could theoretically increase the risk of post-transplant complications like graft-versus-host disease (GVHD) as Moga depletes regulatory T-cells (Tregs). We retrospectively assessed the impact of Moga on post-transplant outcomes using data from a nationwide survey. Pre-transplant administration of Moga was associated with an increased risk of grade 3 to 4 acute GVHD and refractoriness to systemic corticosteroid for acute GVHD. The one-year cumulative incidence of non-relapse mortality was significantly higher in patients who were treated with Moga pre-transplant compared with those who were not (43.7% vs. 25.1%, P<0.01). The probability of one-year overall survival was also significantly lower in patients with pre-transplant Moga use compared to those without (32.3% vs. 49.4%, P<0.01). In summary, pre-transplant Moga was significantly associated with an increased risk of GVHD-related mortality, which supports the relevance of CCR4-expressing Tregs after allo-HSCT in humans.