Abstract: Abstract 3118 Introduction: Elderly patients with myelodysplastic syndromes (MDS) are often lack of suitable human leukocyte antigen (HLA)-matched related donors. Unfortunately, the data on the efficacy of allogeneic transplantation using alternative donor sources are limited. We retrospectively compared the outcomes of HLA 6/6 antigen-matched related bone marrow or peripheral blood progenitor cells (rBM/PBPC) transplantation (6/6rBM/PBPCT), HLA 8/8 allele-matched unrelated bone marrow (uBM) transplantation (8/8uBMT), HLA 7/8 allele-matched uBM transplantation (7/8uBMT), and HLA at least 4/6 antigen-matched single-unit umbilical cord blood (CB) transplantation (sCBT) for elderly patients with MDS. Method: The data were obtained from the Transplant Registry Unified Management Program, which includes data from the Japan Society for Hematopoietic Cell Transplantation, the Japan Marrow Donor Program, and the Japan Cord Blood Bank Network. Patients aged 50–70 years old at transplantation with MDS according to French-American-British (FAB) classification who received first allogeneic transplantation between January 1, 2001 and December 31, 2010 were included. Among 336 rBM/PBPC, 291 uBM, and 215 CB transplantation recipients with complete HLA data, 268 6/6rBM/PBPCT, 147 8/8uBMT, 90 7/8uBMT, and 211 sCBT recipients were included. Cox proportional-hazards regression model was used for adjusted comparisons of the donor sources on overall survival (OS). Fine and Gray proportional-hazards model was used for adjusted comparisons of the donor sources on non-relapse mortality (NRM), relapse, grade 2–4 acute graft-versus-host disease (aGVHD2–4), and neutrophil engraftment. Recipient age at transplantation ( 〉 =60 or 50–59), recipient sex (male or female), performance status (PS) at transplantation (2–4 or 0–1), FAB classification at transplantation (refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEBt), or refractory anemia (RA) and RA with ringed sideroblasts), latest cytogenetics classification according to International Prognostic Scoring System (good, intermediate, poor, or unevaluable), transplant conditioning regimen (reduced-intensity conditioning or myeloablative conditioning), and the year at transplantation (2001–2005 or 2006–2010) were included in the multivariate models. Result: Median follow-up was 2.9 years. The unadjusted 3-year OS rates for recipients of 6/6rBM/PBPCT, 8/8uBMT, 7/8uBMT, and sCBT were 50.7%, 58.2%, 46.2%, and 28.4%, respectively. Multivariate analysis revealed that the OS for sCBT recipients was significantly inferior to those for 6/6rBM/PBPCT (relative risk (RR) [95% confidential interval], 1.9 [1.5–2.5] ; P 〈 0.001), 8/8uBMT (RR, 2.3 [1.7–3.2]; P 〈 0.001), and 7/8uBMT (RR, 1.4 [1.0–2.0]; P=0.047) recipients. The OS for 8/8uBMT and 7/8uBMT recipients were comparable with that for 6/6rBM/PBPCT. Other variables associated with significant inferior OS were recipient age 〉 = 60, male sex, PS 〉 1, FAB classification at transplantation as RAEB/RAEBt, and poor cytogenetics. The risk of relapse for sCBT recipients was comparable with that for 6/6rBM/PBPCT but significantly higher than those for 8/8uBMT (RR, 2.4 [1.5–3.8]; P 〈 0.001) and 7/8uBMT (RR, 2.3 [1.3–4.2]; P=0.005) recipients. The risk of NRM for sCBT recipients was significantly higher than that for 6/6rBM/PBPCT recipients (RR, 1.7 [1.1–2.4] ; P=0.009) but comparable with those for 8/8uBMT and 7/8uBMT recipients. The risk for NRM for 7/8uBMT recipients was significantly higher than that for 6/6rBM/PBPCT (RR, 2.1 [1.4–3.1], P 〈 0.001) and 8/8uBMT (RR, 1.6 [1.1–2.5]; P=0.024) recipients. The risk of aGVHD2–4 for 7/8uBMT recipients was significantly higher than those for 6/6rBM/PBPCT (RR, 1.6 [1.1–2.4] ; P=0.008), 8/8uBMT (RR, 1.7 [1.2–2.6], P=0.008), and sCBT (RR, 1.6 [1.0–2.3] ; P=0.032) recipients. Neutrophil engraftment for sCBT recipients was significantly slower than those for 6/6rBM/PBPCT (RR, 0.26 [0.21–0.33]; P 〈 0.001), 8/8uBMT (RR, 0.35 [0.29–0.43]; P 〈 0.001), and 7/8uBMT (RR, 0.40 [0.31–0.51]; P 〈 0.001) recipients. Conclusion: For elderly patients with MDS, the outcome of sCBT recipient was inferior to those of 6/6rBM/PBPCT, 8/8uBMT, and 7/8uBMT recipients. Decreasing the risk of NRM, which would be brought by improving the neutrophil engraftment, and decreasing the risks of relapse are required to improve the outcome of sCBT. Disclosures: No relevant conflicts of interest to declare.

Abstract: Background: CD56 expression is reported to be associated with adverse prognosis in patients with acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) and chemotherapy (Murray et al, 1999, Ferrara et al, 2000, Montesinos et al, 2011, Ono T et al, 2014). However, the prognostic significance of CD56 has not been elucidated, particularly when more potent agents are used. We recently reported long term analysis of the Japan Adult Leukemia Study Group (JALSG) APL204 study and concluded that maintenance therapy with tamibarotene was more effective than ATRA by reducing relapse in APL patients (Takeshita et al, 2018). In this study, the clinical significance of CD56 was evaluated with other surface markers on APL cells. Patients and Methods: Newly diagnosed APL patients with documented cytogenetic and/or molecular evidence of t(15;17)/PML-RARA were registered to the APL204 study from April 2004 to December 2010. The eligibility criteria included age between 15 and 70 years, ECOG performance status between 0 and 3, and sufficient function of organs. Induction therapy was composed of ATRA and chemotherapy whose dose and duration were based on initial white blood cell (WBC) count. Patients who achieved molecular remission after three courses of consolidation therapy were randomly assigned to maintenance therapy with tamibarotene 6 mg/day for 14 days or ATRA 45 mg/day for 14 days, which was repeated every 3 months for 2 years. The primary endpoint was hematological or molecular relapse-free survival (RFS). Surface markers, including CD56, were defined as positive if more than 10% of the CD45-gated cells expressed a specific antigen. Clinical characteristics were compared by the chi-square test or the Fisher's exact test for categorical data and the Wilcoxon rank-sum test for continuous data. RFS, overall survival (OS) and event-free survival (EFS) were estimated by the Kaplan-Meier method, and compared using the log-rank test. Cumulative incidence of relapse (CIR) was compared by Gray's test. Multivariate analyses were also performed by the Cox-proportional-hazards-model. Clinical outcomes were renewed between January 2016 and June 2017 and the median follow-up period was 7.3 years. This study is registered at the University Hospital Medical Information Network Clinical Trials Registry as C000000154. Results: Of the 344 eligible patients, 319 (93%) achieved CR. After completing consolidation chemotherapy, 269 patients underwent maintenance random assignment; 135 to ATRA, and 134 to tamibarotene. Among 344 eligible patients, 325 were assessable for CD-phenotypes, and 45 (14%) were CD56-positive (CD56+). Among 269 patients who underwent the maintenance assignment, 34 (13%) were CD56+. CD56 expression was significantly associated with obvious bleeding (p 〈 0.001). The CR rate and mortality during induction therapy were not significantly different compared with CD56- APL. RFS and CIR was significantly inferior in CD56+ APL (77% vs. 91%, HR 3.04, 95% CI 1.34-6.90, p=0.005 and 24% vs. 8%, p=0.004, respectively), whereas OS was not significantly different between the two groups 80% vs. 89%, p=0.069). In patients whose initial WBC counts were more than 3.0 x 109/L, RFS for the CD56+ group (n=14) was significantly inferior (64% vs. 87%, p=0.028), while in patients whose initial WBC count was under 3.0 x 109/L (n=20), RFS was not different (85% vs. 93%, p=0.164). Other surface markers such as CD13 and CD33 did not show any prognostic significance except for CD34 (p=0.040). By multivariate analysis, CD56 expression was an independent unfavourable prognostic factor for RFS (HR=3.19, 95% CI 1.40-7.25, p=0.006) together with more than 3.0 x 109/L WBC counts (p=0.001) and the ATRA arm in maintenance therapy (p=0.028). Conclusions: CD56 expression is an independent unfavorable prognostic factor for RFS in APL patients treated with ATRA and chemotherapy followed by ATRA or tamibarotene maintenance therapy, especially in patients whose initial WBC count was more than 3.0 x 109/L. The present study supports the prognostic significance of CD56 in the treatment of APL using more potent agents. Figure. Figure. Disclosures Takeshita: Chugai Pharmaceutical Co. Ltd.: Research Funding; Pfizer Japan Inc.: Research Funding; Astellas Pharma Inc.: Research Funding; Takeda Pharmaceutical Co. Ltd.: Research Funding; Bristol-Myers Squibb Co.: Research Funding; Kyowa Hakko Kirin Co. Ltd.: Research Funding. Asou:Asahi Kasei Pharma Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; SRL Inc.: Consultancy; Yakult Honsha Co., Ltd.: Speakers Bureau; Kyowa Hakko Kirin Co., Ltd.: Speakers Bureau; Astellas Pharma Inc.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding. Sawa:Celgene Corporation: Honoraria; Takeda Pharmaceutical Company Limited: Honoraria; Bristol-Myers Squibb: Honoraria; Novartis International AG: Honoraria; CHUGAI PHARMACEUTICAL CO., LTD.: Honoraria; Mundipharma K.K.: Honoraria. Dobashi:Celgene Co.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co. Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Sysmex Co.: Research Funding. Kobayashi:Pfizer: Research Funding; Ohtuka: Research Funding; Astellas: Research Funding. Kiyoi:Kyowa Hakko Kirin Co., Ltd.: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; Bristol-Myers Squibb: Honoraria; FUJIFILM Corporation: Research Funding; Celgene Corporation: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Sanofi K.K.: Research Funding; Astellas Pharma Inc.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Phizer Japan Inc.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Novartis Pharma K.K.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding.

Abstract: Background Copy-number alterations (CNAs) and gene mutations are hallmarks of cancer genomes, and they are implicated in the development of myeloid neoplasm. However, their relationships have not been fully examined. To address this issue, we have recently developed a novel, next-generation sequencing-based platform for copy-number analysis, which enabled us to detect mutations and CNAs simultaneously. We applied this platform to around 2,000 cases with myeloid neoplasms. Aims We aimed at delineating the landscape of CNAs and their relationships with gene mutations in myeloid neoplasms. Methods We examined 2,101 cases with myeloid neoplasms by whole-exome sequencing (WES) or targeted deep sequencing. Excluding 116 samples showing low qualities of copy-number signals, we performed subsequent analysis on the remaining 1,985 cases with myelodysplastic syndromes (MDS, n = 1,102), myelodysplastic/myeloproliferative neoplasms (MDS/MPN, n = 140), de novo acute myeloid leukemia (de novo AML, n = 448), and secondary AML (sAML, n = 295). In copy-number analysis, total copy numbers and allele-specific copy numbers (ASCNs) were quantified based on sequencing depths and allelic ratios on genome-wide probes. Copy-number signals were corrected for multiple biases (e.g. GC content, ASCN, and fragment length). We also validated the performance of this platform through comparison with SNP-array karyotyping data in 115 de novo AML cases. CNAs longer than 5 Mb were regarded as arm-level CNAs, and those shorter than 5 Mb were regarded as focal CNAs. Results In total, we identified 4,141 CNAs (52.9 % of cases with at least one CNA), and 3,863 mutations (73.9 % of cases with at least one mutation). Most frequent alterations included -7/del(7q) (13.2 %), del(5q) (11.4 %), trisomy 8 (7.2 %), and del(20q) (5.2 %), and mutations of TET2 (12 .3 %), TP53 (11.3 %), ASXL1 (10.1%), and DNMT3A (9.9 %). To evaluate the difference of copy-number landscapes between de novo AML and myelodysplasia (MDS, MDS/MPN, and sAML), we compared the frequencies of CNAs between them. Uni-parental disomy (UPD) of 13q (FLT3) and 11p (WT1), and amplifications of 11q, 13q, and 21q (ERG) were more enriched in de novo AML, while der(1;7), UPD of 11q (CBL), and del(20q) were enriched in myelodysplasia, suggesting differential involvements of CNAs. We next analyzed the correlations between CNA profiles and prognosis in cases with myelodysplasia. Since TP53 status implies a large impact on both patients' prognosis and CNA profiles, we separately analyzed TP53-positive (n = 53) and negative (n = 686) cases with available survival data. In TP53-negative cases, -7/7qLOH (Hazard ratio(HR): 2.28, q 〈 0.001), and UPD of 11q (CBL) (HR: 2.60, q = 0.0034) significantly correlated with shorter overall survivals (OS), while, in TP53-positive cases, amp(11q), +19, and amp(21q) were marginally associated with shorter OS. To delineate the relationships between CNAs and mutations, we interrogated correlations between both lesions among MDS cases without TP53 alterations (n = 937). A number of significant correlations were detected, such as those between trisomy 8 and del(20q) with U2AF1 mutations (q 〈 0.05, for each), and monosomy 7 and amp(21q) with mutations of RUNX1 and NRAS (q 〈 0.01, for each). These correlations were also revealed in clustering analysis based on CNA and mutation profiles, which identified 5 unique clusters: Cluster 1 (n = 171) with trisomy 8, del(20q), and mutations of U2AF1 and ETV6, Cluster 2 (n = 43) with monosomy 7, amp(21q), and mutations of NRAS, SETBP1, and RUNX1, Cluster 3 (n = 19) with amp(1q) and amp(3q), Cluster 4 (n = 127) with those of SF3B1, TET2, and DNMT3A, and Cluster 5 (n = 50) with those of SRSF2, STAG2, ASXL1, and RUNX1. The remaining 527 cases were not assigned into any cluster due to lack of significantly correlated alterations. Finally, the temporal relationships of coexisting alterations were estimated based on their cell fractions; monosomy 7 had significantly greater cell fractions (P = 0.031) and is predicted to precede NRAS mutations, while the cell fractions of U2AF1 mutations tended to be greater than those of trisomy 8 (P = 0.063), suggesting their implications in different stages of disease progression. Conclusion An integrated analysis of CNAs and mutations in 〉 2,000 cases revealed the impacts of CNAs on disease characteristics and provided novel insight into the interplay between CNAs and mutations in the pathogenesis of MDS. Figure Disclosures Atsuta: CHUGAI PHARMACEUTICAL CO., LTD.: Honoraria; Kyowa Kirin Co., Ltd: Honoraria. Kanda:Celgene: Consultancy, Research Funding; Novartis: Research Funding; Shionogi: Consultancy, Honoraria, Research Funding; Nippon-Shinyaku: Research Funding; Taiho: Research Funding; Asahi-Kasei: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Eisai: Consultancy, Honoraria, Research Funding; Eisai: Consultancy, Honoraria, Research Funding; Dainippon Sumitomo: Consultancy, Honoraria, Research Funding; Otsuka: Research Funding; Kyowa-Hakko Kirin: Consultancy, Honoraria, Research Funding; Ono: Consultancy, Honoraria, Research Funding; MSD: Research Funding; Chugai: Consultancy, Honoraria, Research Funding; CSL Behring: Research Funding; Taisho-Toyama: Research Funding; Tanabe Mitsubishi: Research Funding; Dainippon Sumitomo: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Kyowa-Hakko Kirin: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Astellas: Consultancy, Honoraria, Research Funding; Takara-bio: Consultancy, Honoraria; Novartis: Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Sanofi: Research Funding; Pfizer: Research Funding; Asahi-Kasei: Research Funding; Alexion: Consultancy, Honoraria; CSL Behring: Research Funding; Takara-bio: Consultancy, Honoraria; Mochida: Consultancy, Honoraria; Taiho: Research Funding; Celgene: Consultancy, Research Funding; Tanabe Mitsubishi: Research Funding; Taisho-Toyama: Research Funding; Pfizer: Research Funding; Sanofi: Research Funding; Mochida: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Otsuka: Research Funding. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees. Saunthararajah:EpiDestiny: Consultancy, Equity Ownership, Patents & Royalties; Novo Nordisk: Consultancy. Miyazaki:Chugai: Research Funding; Otsuka: Honoraria; Novartis: Honoraria; Nippon-Shinyaku: Honoraria; Dainippon-Sumitomo: Honoraria; Kyowa-Kirin: Honoraria. Usuki:Boehringer-Ingelheim Japan: Other: Received Research ; Daiichi Sankyo: Other: Received Research ; SymBio Pharmaceuticals Limited.,: Other: Received Research ; Novartis: Speakers Bureau; Ono Pharmaceutical: Speakers Bureau; Takeda Pharmaceutica: Speakers Bureau; Chugai Pharmaceutical: Speakers Bureau; Nippon Shinyaku: Speakers Bureau; Mochida Pharmaceutical: Speakers Bureau; MSD K.K.: Speakers Bureau; Celgene Corporation: Other: Received Research , Speakers Bureau; Sumitomo Dainippon Pharma: Other: Received Research , Speakers Bureau; Pfizer Japan: Other: Received Research ; Stellas Pharma: Other: Received Research ; Otsuka: Other: Received Research ; Kyowa Kirin: Other: Received Research ; GlaxoSmithKline K.K.: Other: Received Research ; Sanofi K.K.: Other: Received Research ; Shire Japan: Other: Received Research ; Janssen Pharmaceutical K.K: Other: Received Research . Imada:Bristol-Meyer Squibb K.K.: Honoraria; Celgene K.K.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Kyowa Hakko Kirin Co., Ltd.: Honoraria; Ono Pharmaceutical Co., Ltd.: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; Astellas Pharma Inc.: Honoraria; Novartis Pharma K.K.: Honoraria; Takeda Pharmaceutical Co.,LTD.: Honoraria; Nippon Shinyaku Co.,Ltd.: Honoraria. Takaori-Kondo:Kyowa Kirin: Research Funding; Pfizer: Honoraria; Janssen: Honoraria; Chugai: Research Funding; Takeda: Research Funding; Ono: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria; Celgene: Honoraria, Research Funding. Kiguchi:Celltrion, Inc.: Research Funding; Astellas Pharmaceutical Co., Ltd.: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; MSD CO., Ltd.: Research Funding; Novartis Pharmaceutical Co., Ltd.: Research Funding; Sumitomo Dainippon Pharmaceutical Co., Ltd.: Research Funding; Bristol-Myeres Squibb Co., Ltd.: Research Funding; Janssen Pharmaceutical Co., Ltd.: Research Funding; Celgene Co., Ltd.: Research Funding; SymBio Pharmaceutical Co., Ltd.: Research Funding; Taiho Pharmaceutical Co., Ltd.: Research Funding; Tejin Co., Ltd.: Research Funding; Sanofi K.K., Ltd.: Research Funding. Maciejewski:Alexion: Consultancy; Novartis: Consultancy. Ogawa:Asahi Genomics: Equity Ownership; Qiagen Corporation: Patents & Royalties; Dainippon-Sumitomo Pharmaceutical, Inc.: Research Funding; RegCell Corporation: Equity Ownership; ChordiaTherapeutics, Inc.: Consultancy, Equity Ownership; Kan Research Laboratory, Inc.: Consultancy.

Abstract: The standard treatment for adults with Philadelphia chromosome–positive (Ph+) acute lymphoblastic leukemia (ALL) in Japan is imatinib-based chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT). However, ∼40% of patients cannot undergo HSCT in their first complete remission (CR1) because of chemotherapy-related toxicities or relapse before HSCT or older age. In this study, we evaluated dasatinib-based 2-step induction with the primary end point of 3-year event-free survival (EFS). The first induction (IND1) was dasatinib plus prednisolone to achieve CR, and IND2 was dasatinib plus intensive chemotherapy to achieve minimal residual disease (MRD) negativity. For patients who achieved CR and had an appropriate donor, HSCT during a consolidation phase later than the first consolidation, which included high-dose methotrexate, was recommended. Patients with pretransplantation MRD positivity were assigned to receive prophylactic dasatinib after HSCT. All 78 eligible patients achieved CR or incomplete CR after IND1, and 52.6% achieved MRD negativity after IND2. Nonrelapse mortality (NRM) was not reported. T315I mutation was detected in all 4 hematological relapses before HSCT. Fifty-eight patients (74.4%) underwent HSCT in CR1, and 44 (75.9%) had negative pretransplantation MRD. At a median follow-up of 4.0 years, 3-year EFS and overall survival were 66.2% (95% confidence interval [CI], 54.4-75.5) and 80.5% (95% CI, 69.7-87.7), respectively. The cumulative incidence of relapse and NRM at 3 years from enrollment were 26.1% and 7.8%, respectively. Dasatinib-based 2-step induction was demonstrated to improve 3-year EFS in Ph+ ALL. This study was registered in the UMIN Clinical Trial Registry as #UMIN000012173.

Abstract: Background: Tamibarotene, a new synthetic retinoid, displays (i) approximately 10-fold increased potency over ATRA at inducing in vitro differentiation of NB-4 cells (ii) enhanced chemical stability compared with ATRA (iii) low affinity for cellular RA-binding protein. The clinical efficacy of tamibarotene for the treatment of acute promyelocytic leukemia (APL) has also been reported. A prospective randomized controlled study to evaluate tamibarotene by comparison to ATRA was carried out for maintenance therapy of APL in JALSG APL204 (Shinagawa et al, 2014). The 4-year-relapse free survival (RFS) did not differ between patients treated with ATRA or tamibarotene. However, an improved efficacy of tamibarotene in high-risk patients was suggested, which warrants further investigation. Here, we evaluate the long-term outcome of the study. Patients and Methods: Patients enrolled in this study were newly diagnosed with APL and documented cytogenetic and/or molecular evidence of t(15;17)/ PML-RARA . The age of the patients ranged between 15 and 70 years and the ECOG performance status was between 0 and 3. For remission induction therapy, ATRA was administered to all patients at a daily dose of 45 mg/m2 until complete remission (CR). The chemotherapy protocol varied depending on the initial leukocyte count and blast count in the peripheral blood. In brief, patient groups were defined as: leukocytes & lt; 3,000/µl (Group A: ATRA alone), 3,000/µl ≤ leukocytes & lt; 10,000/µl (Group B: ATRA plus IDA/Ara-C: 2+5), and leukocytes ≥ 10,000/µl (Group C: ATRA plus IDA/Ara-C: 3+5). Those patients who experienced leukocytosis received additional chemotherapy (Group D). Patients who achieved molecular remission after consolidation chemotherapy were randomly assigned to 2 groups of maintenance therapy, and administered tamibarotene at a daily dose of 6 mg/m2 divided into 2 doses for 14 days or ATRA at a daily dose of 45 mg/m2 divided into 3 doses for 14 days. Each cycle of treatment was repeated every 3 months for 2 years. The primary endpoint was hematological or molecular relapse-free survival (RFS) during the maintenance and follow up period. This study is registered at the University Hospital Medical Information Network Clinical Trials Registry as C000000154. Results: A total of 347 patients were enrolled in the study. Of the 344 eligible patients, 319 (93%) achieved CR. After completing three courses of consolidation therapy, 269 patients underwent maintenance random assignment; 135 patients were assigned to ATRA, and 134 patients were assigned to tamibarotene. The mean follow-up of patients alive and relapse-free at the date of last contact was 7 years. The 7-year RFS rate was 84% for the ATRA arm and 93% for the tamibarotene arm (p=0.031) (Fig.1). When the analysis was restricted to 52 high-risk patients with an initial leukocyte count ≥ 10,000/µl, the difference was more prominent (62% vs 89%, p=0.034) (Fig.2). The 7-year RFS of induction treatment for Group A (92 cases) was 91%, Group B (38 cases) 92%, Group C (52 cases) 75% and Group D (87 cases) 91% (p=0.005). Both treatments were generally well tolerated. Secondary hematopoietic disorders were observed in 12 cases, malignancies in 9 cases, late cardiac complications (grade 3 or more) in 5 cases. However, there was no significant difference in terms of these complications between the two treatment groups. Conclusions: Maintenance therapy with tamibarotene was effective at decreasing the relapse rate in APL patients by comparison to ATRA at the 7-year observation point. In particular, tamibarotene was significantly more effective than ATRA for high risk patients with leukocytes ≧10,000/μl. These results could lead to a new strategy for the treatment of high risk patients, which is one of the recent priority issues in the treatment of APL. Disclosures Takeshita: Chugai Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding; Phizer Japan Inc.: Research Funding; Takeda Pharmaceutical Co Ltd: Research Funding. Asou: Chugai Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Research Funding. Ueda: KAINOS LABORATORIES INC: Membership on an entity's Board of Directors or advisory committees; Abrynx nv: Membership on an entity's Board of Directors or advisory committees; Elli LiLLY Japan KK: Other: Clinical Trial; Takeda PharmaceuticalCompany Limited: Other: Clinical TRial; Otsuka Pharmaceutical Co Ltd: Other: Clinical Trial; Celgene KK: Other: Clinical Trial; Symbio Pharmaceutical Limited: Other: Clinical Trial; AstellasPharma Inc: Other: Clinical Trial; Eisai Co. Ltd: Other: Clinical Trial. Fujita: Chugai Pharmaceutical: Honoraria. Usui: Nippon Shinyaku Pharmaceutical Co: Research Funding. Kobayashi: Pfizer, Ohtsuka, Astellas, Ariad: Research Funding. Kiyoi: Kyowa Hakko Kirin Co., Ltd.: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; ONO Pharmaceutical Co., Ltd.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Meiji Seika Pharma Co.,Ltd.: Research Funding; FUJIFILM Corporation: Patents & Royalties, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Eisai Co., Ltd.: Research Funding; Celgene Corporation: Consultancy, Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Phizer Japan Inc.: Honoraria, Research Funding; MSD K.K.: Research Funding; Novartis Pharma K.K.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; JCR Pharmaceuticals Co.,Ltd.: Research Funding. Atsuta: Otsuka Pharmaceutical Co., Ltd.: Honoraria. Naoe: Otsuka Pharmaceutical Co.,Ltd.: Honoraria, Research Funding; Nippon Boehringer Ingelheim Co.: Honoraria, Research Funding; Fujifilm Corporation: Patents & Royalties, Research Funding; Dainippon Sumitomo Pharma Co.,LTD.: Research Funding; Astellas Pharma Inc.: Research Funding; Toyama Chemikal Co.,Ltd.: Research Funding. Miyazaki: Nippon Shinyaku: Honoraria.

Abstract: Abstract 2641 INTRODUCTION: Since the introduction of the anti-CD20 monoclonal antibody rituximab, the outcomes of B-cell non-Hodgkin lymphoma (B-NHL) have improved markedly. However, fulminant hepatitis due to reactivation of hepatitis B virus (HBV) infection has emerged as a serious problem. Recently, rituximab plus corticosteroid containing chemotherapy (R-chemo) has been identified as a risk factor for HBV reactivation in hepatitis B surface antigen (HBsAg)-negative B-NHL patients. Currently, there is no standard management to prevent HBV reactivation in HBV-resolved patients without HBsAg, but with antibodies against hepatitis B core antigen (anti-HBc) and/or HBsAg (anti-HBs). PATIENTS AND METHODS: We conducted a multicenter prospective observational study to estimate the incidence of HBV reactivation by serial monthly monitoring of HBV DNA in HBV-resolved patients with B-NHL during and just after R-chemo, and to establish preemptive antiviral therapy guided by this monitoring. The major eligibility criteria included previously untreated CD20-positive B-NHL with prior HBV-resolved infection, and planned treatment with 6 to 8 cycles of R-chemo defined by protocol. The baseline HBV status was evaluated on enrollment at each institute, comprising HBsAg, anti-HBc, and anti-HBs serology. Patients were excluded if they were seropositive for hepatitis C virus or human immunodeficiency virus. Plasma HBV DNA levels were measured independently at a central laboratory, using an automated real-time TaqMan polymerase chain reaction assay after enrollment. The primary end point was the incidence of HBV reactivation defined as HBV DNA levels of 1.8 log copies per mL or more. If HBV DNA levels of less than 1.8 log copies per mL were confirmed at baseline, the serial monitoring of HBV DNA (without prophylaxis of antiviral drugs) was performed with assessments every 4 weeks after enrollment for 1.5 years. Prompt antiviral treatment with an anti-HBV nucleoside analogue (entecavir, 0.5 mg per day) was highly recommended in patients with confirmed HBV reactivation. An ancillary study was conducted to identify risk factors for HBV reactivation using the preserved specimens. The protocol was approved by the Institutional Review Board of each participating institution. All patients gave written informed consent. The planned interim analysis was performed after the enrollment of 200 patients, using data available up to June 30, 2011. RESULTS: Between Sept. 2008 and Sept. 2010, a total of 187 patients (50.8% male) with a median age of 63 years (range, 26 to 79) from 45 institutes were analyzed. Histologic subtypes of B-NHL were diffuse large B-cell lymphoma (n=121, 64.7%), follicular lymphoma (n=57, 30.5%), MALT lymphoma (n=5, 2.7%) and other types (n=4, 2.0%). The number (%) of patients positive for both anti-HBc and anti-HBs was 132 (70.6%), 35 (18.7%) were positive for anti-HBc but negative for anti-HBs, and 19 (10.2%) were negative for anti-HBc but positive for anti-HBs. One patient was positive for anti-HBc but lacked anti-HBs measurement. 168 (89.8%) patients received 6 to 8 cycles of R-CHOP (n=151) or other R-chemo (n=17). With a median follow-up of 549 days (range, 35 to 939), HBV reactivation was observed in 16 out of 187 analyzed patients. The incidence of HBV reactivation at 1 year was 7.7% (95% confidence interval [CI], 4.7 to 12.7). HBV reactivation was diagnosed at a median time of 158 days (range, 33 to 490) after enrollment. No hepatitis due to HBV reactivation was observed in patients who received antiviral treatment when HBV DNA levels were 1.8 to 3.1 log copies per mL. Multivariate analysis of the ancillary study showed that an anti-HBs baseline titer less than 10 mIU per mL was an independent risk factor for HBV reactivation, compared to a titer of 100 mIU per mL or more (adjusted hazard ratio, 5.3; 95% CI, 1.3 to 21.8; p=0.02). HBV mutations of precore (G1896A) or basal core promoter (A1762T/G1764A) that enhanced HBV replication were identified in 4 patients, two of whom had both mutations. Our strategy could inhibit such highly replicative clones and prevent hepatitis. CONCLUSIONS: Monthly monitoring of HBV DNA is highly effective for preventing hepatitis due to HBV reactivation in HBV-resolved B-NHL patients treated with R-chemo. (UMIN-CTR 000001299) (This study was supported by the Ministry of Health, Labour and Welfare of Japan.) Disclosures: Kusumoto: Bristol-Myers Squibb: Honoraria; Zenyaku Kogyo: Honoraria; Chugai Pharmaceutical Co., LTD.: Honoraria, Research Funding; Abbott: Honoraria. Tanaka:Chugai Pharmaceutical Co., LTD.: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Zenyaku Kogyo: Honoraria; Abbott: Honoraria. Tanaka:Chugai Pharmaceutical Co., LTD.: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Kinoshita:Chugai Pharmaceutical Co., LTD.: Honoraria, Research Funding; Zenyaku Kogyo: Honoraria. Ogura:Chugai Pharmaceutical Co., LTD.: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Zenyaku Kogyo: Honoraria, Research Funding. Mizokami:Chugai Pharmaceutical Co., LTD.: Honoraria; Abbott laboratories: Honoraria. Ueda:Chugai Pharmaceutical Co., LTD.: Research Funding.