ALBERT

Description: 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

Description: Key Points GWAS can identify allele mismatch associated with aGVHD development. Three novel candidate loci for minor histocompatibility antigens significantly associate with aGVHD.

Description: Although the effects of human leukocyte antigen (HLA) locus matching on clinical outcome in unrelated hematopoietic stem cell transplantations have been characterized, the biologic implications of HLA haplotypes have not been defined. We demonstrated the genetic fixity of Japanese conserved extended haplotypes by multi–single nucleotide polymorphism analysis in 1810 Japanese donor-recipient pairs matching with HLA-A, -B, -C, -DRB1, and -DQB1 alleles. Three major Japanese conserved extended haplotypes (named HP-P1, HP-P2, and HP-P3) were essentially completely conserved at least in the 3.3-Mb HLA region from HLA-A to -DPB1, and extended far beyond HLA-A. The risk of acute graft-versus-host disease (GVHD) of these HLA haplotypes was assessed with multivariate Cox regression in 712 patients transplanted from HLA fully (HLA-A, B, C, DRB1, DQB1, and DPB1) matched unrelated donors. HP-P2 itself reduced the risk of grade 2 to 4 acute GVHD (hazard ratio [HR] = 0.63; P = .032 compared with HP-P2-negative), whereas HP-P3 tended to increase the risk (HR = 1.38; P = .07). Among 381 patients with HP-P1, HP-P1/P3 (HR = 3.35; P = .024) significantly increased the risk of acute GVHD compared with homozygous HP-P1. This study is the first to demonstrate that a genetic difference derived from HLA haplotype itself is associated with acute GVHD in allogeneic hematopoietic stem cell transplantation.

Description: Key Points Significant HLA locus mismatches responsible for transplant-related events were determined in 7898 unrelated marrow donor transplants. This information provides a rationale for use of an algorithm for unrelated donor selection.

Description: Minor histocompatibility antigens (mHAgs) with expression limited to hematopoietic cells represent attractive targets for immunotherapy to induce selective graft-versus-leukemia (GVL) reactions. Here we report the identification of a novel mHAg which is recognized by an HLA-B*4403-restricted CTL clone. Microsatellite allele image analysis of two DNA pools generated from CTL-defined mHAg positive and mHAg negative groups was performed using microsatellite markers set at 100 kb intervals within the segment initially mapped by two-point genetic linkage analysis and detailed mapping of the chromosomal recombinant points. This approach defined a 0.53 Mbp region of chromosome 18q21–22 containing 12 candidate genes potentially encoding the mHAg, although the target gene could not be identified. Subsequently, cDNA expression cloning studies demonstrated that the CTL epitope of interest was encoded by a novel allelic splice variant of XM_209104, hereafter designated as XM_209104-av. Indeed, this gene was found to lie within the region predicted by microsatellite allele image analysis. The immunogenicity of the epitope was generated by differential protein expression due to alternative splicing, which was completely controlled by one intronic single nucleotide polymorphism (SNP) located in the consensus 5′ splice site adjacent to an exon. To our knowledge, this is the first example of a mHAg controlled by a SNP located in a region other than coding sequences. Because the CTL lysed also HLA-B*4402 positive, mHAg positive B-LCLs, this novel epitope peptide can bind to not only HLA-B*4403 but also HLA-B*4402 which is a relatively common HLA-B allele in Caucasian populations. Finally, the finding that the novel XM_209104-av showed low or no expression in normal tissues including resting hematopoietic cells, but significantly higher expression in primary acute leukemia cells, especially those of myeloid lineage, suggest that this novel epitope may be an attractive therapeutic target for immunotherapy not only as a minor H antigen but also as a leukemia-associated antigen.

Description: Introduction Epstein-Barr virus (EBV) is a double-stranded DNA virus that infects 〉95% of the human population and is associated with a substantial risk of cancer development. Most infections in children and adolescents are asymptomatic or result in infectious mononucleosis; however, in some patients, EBV is associated with various hematological malignancies including Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and extranodal NK/T-cell lymphoma. EBV infection is also present in a portion of epithelial cell neoplasms such as gastric cancer and nasopharyngeal carcinoma. Despite the large population risk of cancer associated with EBV, it is poorly understood why only a small subset of EBV-infected individuals develop neoplasms, while others do not. Patients and Methods We designed a target enrichment system to capture several EBV strains including the Akata strain, which is responsible for the majority of EBV infections in Japan. We analyzed the genomes of EBV strains in 139 patients with various EBV-associated diseases and 17 EBV-positive cell lines. Next-generation sequencing reads were aligned to the Akata reference genome to analyze nucleotide variations, copy number alterations, and structural variations including sequence insertions in the human genome. The institutional review board of Nagoya University Graduate School of Medicine approved this study. Results We identified a median of 645 single nucleotide variants (SNVs) in the EBV genomes, 78% of which affected coding sequences. SNVs in coding sequences were significantly biased toward synonymous variants, suggesting negative selection pressure. The SNVs detected in noncoding sequences were enriched in two evolutionarily conserved viral noncoding RNAs (EBER1 and EBER2), particularly in the PAX5-binding domain of EBER2. However, most SNVs identified in the EBV genome do not seem to affect the development of neoplasms, as hierarchical clustering of EBV genomes from neoplastic and non-neoplastic diseases based on SNVs revealed no significant association between the EBV strain and disease type. In addition to SNVs, we identified frequent intragenic deletions in the EBV genomes of patients with EBV-positive DLBCL (10/14, 71%), extranodal NK/T-cell lymphoma (10/23, 43%), chronic active EBV infection (27/77, 35%), and other EBV-associated neoplasms (2/7). Such deletions were also identified in several EBV-associated cell lines (6/17), but not in non-neoplastic diseases such as infectious mononucleosis (0/4) and post-transplant lymphoproliferative disorders (0/14), suggesting a unique role of these mutations in the neoplastic proliferation of EBV-infected cells. Frequent deletions were detected in BamHI A rightward transcripts microRNA clusters (31/156), which suppress viral transcription factors (BZLF1 and BRLF1) required for the lytic reactivation of EBV. Deletions also were associated with several genes essential for virus production (20/156). These observed deletions are thought to upregulate lytic cycle-associated genes, some of which benefit neoplasms by inducing genomic instability and immune escape and mitigate cell damage caused by the production of viral particles. In fact, deletion of one essential gene, BALF5, resulted in upregulation of the lytic cycle and promotion of lymphomagenesis in a xenograft model. Discussion Although the essential roles of several latency-associated genes, such as LMP-1 and EBNA-2, in EBV-mediated immortalization and transformation of human lymphocytes have long been discussed, our finding raises the possibility that lytic cycle-associated genes also contribute to lymphomagenesis. This agrees with reports that lytic cycle-associated genes are expressed in Burkitt lymphoma, DLBCL, and chronic active EBV infection, and that BZLF1-deficient lymphoblastoid cells exhibit significantly impaired tumorigenicity in mice. In addition, essential gene deletions lead to the protection of EBV-infected cells from lysis. Further studies are warranted to exploit these findings for the design of novel therapeutics for EBV-associated neoplasms. Disclosures Kiyoi: Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Novartis Pharma K.K.: Research Funding; Phizer Japan Inc.: Research Funding; Sanofi K.K.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Celgene Corporation: Research Funding; Eisai Co., Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; FUJIFILM Corporation: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Bristol-Myers Squibb: Honoraria. Nakamura:Roche/Chugai,: Research Funding; Kyowa-Kirin: Research Funding.

Description: Introduction: Enhancer of zeste homolog 2 (EZH2) and EZH1 are alternative subunits of polycomb repressive complex 2 that catalyze the tri-methylation of lysine 27 residue of histone H3. This histone modification epigenetically regulates gene expression and may play an important role in tumor progression. Valemetostat (DS-3201) is a potent and highly specific orally bioavailable dual inhibitor of EZH2 and EZH1 demonstrating anti-tumor activity against various hematological malignancies in preclinical studies (Honma D, et al. Cancer Sci 2017; Fujita S, et al. Leukemia 2018). Valemetostat demonstrated clinical activity as a novel oral therapeutic option for both B-cell and T-cell NHLs in the interim analysis of a phase I study (Maruyama D, et al. ASH 2017). Here we report the updated results of this phase I study focusing on ATL patients. ATL is a peripheral T-cell malignancy caused by human T-cell leukemia virus type I (HTLV-1), and is divided into aggressive and indolent subtypes. Aggressive ATL has an extremely poor prognosis, with a median survival time of only 8 to 10 months (Katsuya H, et al. Blood 2015). Although conventional chemotherapeutic agents, anti-CCR4 antibody mogamulizmab, and oral immunomodulator lenalidomide have been used for treatment of aggressive ATL patients, most patients eventually become resistant to treatment. In addition, allogenic hematopoietic stem cell transplantation is not available for elderly patients. Therefore, new therapeutic options are urgently needed. Methods: This ongoing open-label, single-arm phase I study consists of the dose escalation part (NHLs including ATL and peripheral T-cell lymphoma [PTCL]) and the expansion part (ATL and PTCL). The drug was administered orally once daily (QD) continuously over 28-days (1 cycle) until disease progression or intolerance. Results: Thirty-eight patients (15 females) with a median age of 69 (44-88) were enrolled in this study as of the data cut-off of 24 January 2019. Of 38 patients, 25 patients were enrolled in the dose-escalation part, and additional 13 patients (7 ATLs and 6 PTCLs) were treated in the expansion part with 200 mg of valemetostat. In all patients, adverse events (≥30%) on treatment with all grades included; platelet count decreased (73.7%), dysgeusia (52.6%), anemia (42.1%), lymphocyte count decreased (39.5%), neutrophil count decreased (39.5%), and white blood cell count decreased (39.5%). Preliminary efficacy was based on investigator's assessment with an objective response rate (ORR) of 47.2%. Fifteen patients were able to stay on valemetostat for more than 24 weeks with tumor shrinkage. Of the 9 ATL patients in the study (2 in dose escalation and 7 in dose expansion), baseline characteristics are as follows: age, median age 74 (range 61-78 yrs); sex, 7 males and 2 females; ATL subtype, 6 acute- and 3 lymphoma-subtypes; median number of prior therapies, 2 (range 1-8). Adverse events (≥30%) on treatment with all grades in the 9 ATL patients included; platelet count decreased (77.8%), dysgeusia (66.7%), neutrophil count decreased (44.4%), white blood cell count decreased (44.4%), anemia (33.3%), alopecia (33.3%), and dry skin (33.3%). No grade 4 and 5 adverse events were detected. Grade 3 adverse events included; white blood cell count decreased (33.3%), platelet count decreased (22.2%), neutrophil count decreased (22.2%), lymphocyte count decreased (11.1%), and anemia (11.1%), which are consistent with those in all population. Responses for the 9 ATL patients included; 1 unconfirmed complete remission (CRu), 3 partial remission (PR), and 3 stable disease (SD) (ORR = 44.4%; 4/9). Of the 6 prior mogamulizumab treated patients, 3 patients demonstrated a response (ORR = 50%; 3/6). Five of 9 ATL patients continued on valemetostat treatment for more than 12 weeks with tumor shrinkage (Figure). Four ATL patients continue on treatment. The latest study results will be presented. Conclusion: The updated results of this ongoing phase I study showed that the oral EZH1/2 dual inhibitor valemetostat has demonstrated acceptable safety and promising preliminary efficacy in NHL. In addition, the results of ATL patients, including mogamulizumab pretreated patients, showed promising clinical activity. A subsequent pivotal phase II study for ATL will soon be initiated. Clinical trial information: NCT02732275 Disclosures Ishitsuka: Novartis: Honoraria, Research Funding; sanofi: Honoraria; Celgene: Honoraria; Astellas Pharma: Honoraria, Research Funding; Pfizer: Honoraria; Takeda Pharmaceutical: Honoraria, Research Funding; Janssen Pharmaceutical: Honoraria; Janssen Pharmaceutical: Honoraria; Shire: Honoraria; Eisai: Honoraria, Research Funding; Otsuka Pharmaceutical: Honoraria; Mochida: Honoraria, Research Funding; Shire: Honoraria; Teijin Pharma: Research Funding; Sumitomo Dainippon Pharma: Honoraria, Research Funding; Astellas Pharma: Honoraria, Research Funding; Sumitomo Dainippon Pharma: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Genzyme: Honoraria; Genzyme: Honoraria; Eisai: Honoraria, Research Funding; Ono Pharmaceutical: Honoraria, Research Funding; Teijin Pharma: Research Funding; MSD: Research Funding; Yakult: Research Funding; Asahi kasei: Research Funding; MSD: Research Funding; Asahi kasei: Research Funding; Eli Lilly: Research Funding; Eli Lilly: Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Kyowa Hakko Kirin: Honoraria, Research Funding; mundiharma: Honoraria; Taiho Pharmaceutical: Honoraria, Research Funding; Alexion: Honoraria; Mochida: Honoraria, Research Funding; Takeda Pharmaceutical: Honoraria, Research Funding; mundiharma: Honoraria; Taiho Pharmaceutical: Honoraria, Research Funding; Otsuka Pharmaceutical: Honoraria; Ono Pharmaceutical: Honoraria, Research Funding; Yakult: Research Funding; Bristol-Myers Squibb: Honoraria; Chugai Pharmaceutical: Honoraria, Research Funding; Pfizer: Honoraria; Alexion: Honoraria; sanofi: Honoraria. Izutsu:Eisai, Chugai, Zenyaku: Honoraria; Chugai, Celgene, Daiichi Sankyo, Astra Zeneca, Eisai, Symbio, Ono, Bayer, Solasia, Zenyaku, Incyte, Novartis, Sanofi, HUYA Bioscience, MSD, Astellas Amgen, Abbvie, ARIAD, Takeda, Pfizer: Research Funding; Celgene: Consultancy; Eisai, Symbio, Chugai, Zenyaku: Research Funding; Kyowa Kirin, Eisai, Takeda, MSD, Chugai, Nihon Medi-physics, Janssen, Ono, Abbvie, Dainihon Sumitomo, Bayer, Astra Zeneca, HUYA Japan, Novartis, Bristol-Byers Squibb, Mundi, Otsuka, Daiichi Sankyo, Astellas, Asahi Kasei: Honoraria. Kusumoto:Chugai Pharmaceutical Co., Ltd.: Consultancy, Honoraria, Research Funding; Kyowa Kirin Co., Ltd.: Honoraria, Research Funding. Araki:Daiichi Sankyo: Employment. Adachi:Daiichi Sankyo: Employment. Yamashita:Daiichi Sankyo: Employment. Atsumi:Daiichi Sankyo: Employment. Tsukasaki:Eisai: Research Funding; Mundi Pharma: Honoraria; Chugai Pharmaceutical: Honoraria, Research Funding; Huya: Consultancy, Honoraria, Research Funding; Byer: Research Funding; Kyowa Kirin: Honoraria; Ono Pharmaceutical: Consultancy; Celgene: Honoraria, Research Funding; Daiichi Sankyo: Consultancy. Tobinai:Eisai: Honoraria, Research Funding; Kyowa Kirin: Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Takeda Pharmaceutical: Consultancy, Honoraria, Research Funding; Chugai Pharmaceutical: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Zenyaku Kogyo: Consultancy, Honoraria; Meiji Seika: Honoraria; Verastem: Honoraria; Solasia: Honoraria; Janssen Pharmaceutical: Honoraria, Research Funding; Yakult: Honoraria; AbbVie: Research Funding; Ono Pharmaceutical: Consultancy, Honoraria, Research Funding; Mundi Pharma: Consultancy, Honoraria, Research Funding; HUYA Bioscience: Consultancy, Honoraria; Bristol-Myers Squibb: Honoraria.

Description: Idiopathic aplastic anemia (AA) is a common cause of acquired BM failure. Although autoimmunity to hematopoietic progenitors is thought to be responsible for its pathogenesis, little is known about the molecular basis of this autoimmunity. Here we show that a substantial proportion of AA patients harbor clonal hematopoiesis characterized by the presence of acquired copy number-neutral loss of heterozygosity (CNN-LOH) of the 6p arms (6pLOH). The 6pLOH commonly involved the HLA locus, leading to loss of one HLA haplotype. Loss of HLA-A expression from multiple lineages of leukocytes was confirmed by flow cytometry in all 6pLOH(+) cases. Surprisingly, the missing HLA-alleles in 6pLOH(+) clones were conspicuously biased to particular alleles, including HLA-A*02:01, A*02:06, A*31:01, and B*40:02. A large-scale epidemiologic study on the HLA alleles of patients with various hematologic diseases revealed that the 4 HLA alleles were over-represented in the germline of AA patients. These findings indicate that the 6pLOH(+) hematopoiesis found in AA represents “escapes” hematopoiesis from the autoimmunity, which is mediated by cytotoxic T cells that target the relevant auto-antigens presented on hematopoietic progenitors through these class I HLAs. Our results provide a novel insight into the genetic basis of the pathogenesis of AA.