ALBERT

Description: Abstract 3090 Poster Board III-27 The outcome of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) has dramatically improved since the start of treatment with imatinib. The Japan Adult Leukemia Study Group (JALSG) has reported a high complete remission (CR) rate for Ph+ALL treated with imatinib-combined chemotherapy (Yanada et al, J Clin Oncol 2006). Here we report a follow-up analysis of the results of the JALSG imatinib-combined chemotherapy. In the study, remission was induced by administering imatinib from day 8 to day 62 in combination with cyclophosphamide, daunorubicin, vincristine (VCR), and prednisolone (PSL). Consolidation regimen consisted of an odd course comprising high-dose methotrexate and high-dose cytarabine and an even course with 28 days administration of single-agent imatinib. The consolidation regimens were alternated for four courses each. Maintenance consisting of VCR, PSL, and imatinib was continued for two years after a CR. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was recommended if HLA identical sibling donor was available and was allowed from an alternative donor. A total of 103 newly diagnosed Ph+ALL patients were enrolled in the study between August 2002 and August 2004. Median age of the patients was 45 years (range, 15-64 years), and there were 57 males and 46 females. Median follow-up period was 2.6 years (range, 0.1-5.1 years). A CR was achieved in 100 (97.1%) of the 103 patients and not achieved in a patient in whom imatinib was discontinued because of ileus. There were two early deaths during induction. The probability of overall survival (OS) rate for the entire group at three years was 56.8%. No severe adverse effects were observed. Allo-HSCT was performed in the 1st CR (CR1) in 54 of the 74 CR patients under 55 years of age. Relapse occurred in 18 of 20 patients (90.0%) in whom allo-HSCT was not performed in CR1, but in only seven of the 54 patients (13.0%) who underwent allo-HSCT. At three years, the probability of OS rate for patients under 55 years of age was 75.0% in the transplanted group and 36.4% in the non-transplanted group. Allo-HSCT was performed in CR1 in eight of the 25 patients over 55 years of age. Two were myeloablative and six reduced intensity conditionings. Seven of eight patients who underwent HSCT are still alive in a CR. However, the probability of OS rate at three years in the non-transplanted group was 43.2%. In the group that did not receive allo-HSCT in CR1, age (55〈 years or 55〉 years), WBC count, bcr/abl transcript level, bcr/abl transcript type (major or minor), co-expression of myeloid antigens (CD13 and/or CD33), and additional chromosomal abnormalities at diagnosis were not associated with OS. The results demonstrated that the imatinib-combined chemotherapy regimen was effective and feasible. The regimen provided a better chance to receive allo-HSCT which resulted in an excellent outcome. However, relapse still remains a problem, especially in patients who are not candidates for allo-HSCT. Disclosures No relevant conflicts of interest to declare.

Description: Background In patients with Myelodysplastic Syndromes (MDS), TP53 mutations associate with high-risk presentation, complex karyotype, acute myeloid leukemia (AML) progression and poor response to hematopoietic stem cell transplantation. These associations highlight the relevance of TP53 as a prognostic and predictive biomarker. Consistent with its role as a tumor suppressor, bi-allelic targeting of the TP53 locus is a frequent but not an obligatory event. Despite the central role of TP53 in MDS, the clinical implications of TP53 mutations in the context of allelic state have not been extensively studied. Methods Under the auspices of the International Working Group for Prognosis in MDS, we sequenced a representative cohort of 3,324 peri-diagnosis MDS patients on a next generation sequencing (NGS) panel optimized for myeloid disease. Conventional G-banding analysis (CBA) was available for 2,931 patients. Focal (~3MB) gains and deletions and regions of NGS-derived copy-neutral loss of heterozygosity (cnLOH) were assessed using an in-house algorithm CNACS. Putative oncogenic mutations in TP53 were characterized by consideration of normal controls and established population databases. A validation cohort of 1,120 samples with independent but comparable molecular and clinical annotation was sourced from a compendium of Japanese MDS data to include JALSG-MDS212, JMDP registry, and regional registries. Results NGS-derived ploidy alterations and CBA show a high genome-wide concordance. From NGS profiles, 11% of patients (n=360) are subject to cnLOH, of which 80 target the TP53 locus. We characterize 490 TP53 mutations in 380 patients, representing 11% of the cohort. Amongst those patients, 22% (n=85) and 21% (n=78) have a deletion or a cnLOH involving the TP53 locus, respectively. Taken together, these segregate patients into two TP53 states: a mono-allelic state where one wild type allele remains (33% of TP53 mutated patients, n=126); and a multi-hit state where TP53 is altered multiple times by either mutations, deletions or cnLOH (67% of TP53 mutated patients, n=254). We find that TP53 state shapes clinical presentation and outcomes. Mono-allelic TP53 patients present with more favorable disease than multi-hit TP53 patients: they are less cytopenic, have lower bone marrow blasts (median 4 vs. 9%, p

Description: Introduction: In recent decades, a considerable number of tumor antigens have been characterized, including the leukemia-associated antigen, Wilm's tumor 1 (WT1). WT1 is found to be expressed at low levels in various normal tissues such as gonads, kidney and the hematopoietic system. However, it is highly overexpressed in various hematological malignancies and solid tumors, including in the majority of acute myeloid leukemia (AML) cases. OCV-501 is a human leukocyte antigen (HLA) class II-restricted helper peptide derived from the WT1 protein. This Phase II trial was conducted to evaluate the efficacy and safety of OCV-501 in elderly patients with AML (ClinicalTrials.gov identifier: NCT01961882). Methods: This multicenter, randomized, double-blind, placebo-controlled trial was conducted in Japan, the Republic of Korea and Taiwan between October, 2013 to November, 2017. The key eligibility criteria for this trial were patients with AML, aged 60 years or older, who achieved first complete remission within one or two courses of standard induction therapy, completed more than one course of standard consolidation therapy, and not scheduled for hematopoietic stem cell transplantation. Patients were assigned to receive either OCV-501 monotherapy or placebo. Subcutaneous administration of OCV-501 3mg or placebo was given once weekly up to the eighth administration, and once biweekly from the ninth administration onwards up to a duration of 2 years, followed by post-treatment observation period. The primary endpoint was disease-free survival (DFS) that was defined as the time from randomization to AML relapse or death from any cause, whichever came first, within the observation period. Secondary endpoints were overall survival (OS), quality of life (QOL; The European Organization for Research and Treatment of cancer [EORTC] QLQ-C30), and performance status (Eastern Cooperative Oncology Group performance status [ECOG PS]). Safety, including any occurrence of adverse events (AEs) was evaluated. Results: A total of 133 patients who had achieved first remission after prior induction and consolidation therapies were randomized to receive either OCV-501 (OCV-501 arm, N=68) or placebo (placebo arm, N=65). The median age of the patients was 67 years (range, 60 - 85) and most of them had good performance status (ECOG PS score 0 - 1). The WT1 mRNA level at Day 1 was

Description: Background:Rigosertib is a novel phosphoinositide 3 kinase pathway inhibitor that induces G2/M arrest leading to the apoptosis of cancer cells and myeloblasts and causes minimal damage to normal cells. A Phase I study in the U.S. showed the safety and good tolerability of oral rigosertib in patients (pts) with low, intermediate-1, intermediate-2, or high risk myelodysplastic syndromes (MDS). Methods:A multicenter, open-label Phase I clinical study was conducted to examine the tolerability of oral rigosertib in Japanese pts with recurrent/relapsed or refractory MDS, and to determine the recommended dose for a Phase II clinical study. The key eligibility criteria were as follows: patients with recurrent/relapsed or refractory MDS, aged 20 years or older, ECOG PS of 0 to 2, and no major organ dysfunctions. Rigosertib (280 and 560 mg BID) was administered orally in one 21-day cycle that consisted of the 14-day, twice-daily, oral administration term, followed by the 7-day monitoring term. In principle, oral rigosertib was administered in up to cycle 6. The primary endpoint was the dose-limiting toxicity (DLT) in each dose group. The secondary endpoints were as follows: 1) safety as assessed with adverse events (AEs) and laboratory results; 2) efficacy as assessed according to the International Working Group 2006 criteria; and 3) pharmacokinetics. Results: Between March 2013 and November 2014, 10 patients were enrolled at 7 medical institutions in Japan. However, 1 of them did not receive rigosertib because of a tendency for PS deterioration. Six pts were male, the median age was 70 years (range 52 to 80 years), and ECOG PS was 0 in 7 pts and was 1 in 2 pts. Consequently, 3 and 6 pts were eventually assigned to the 280 and 560 mg dose groups, respectively. According to the FAB classification, 4, 2, 2, and 1 pts were categorized to RAEB, RARS, RA, and RAEB-t, respectively. The prognostic factor according to IPSS was Int-1 risk in 4 pts (1 and 3 pts in the 280 and 560 mg dose groups, respectively) and was Int-2 in 5 pts (2 and 3 pts in the 280 and 560 mg dose groups, respectively). In the 280 mg dose group, 2 of 3 pts completed cycle 6, and the median relative dose intensity (RDI) was 86% (77 to 92%). In the 560 mg dose group, the maximum number of cycles delivered was 4, and the median RDI was 85% (68 to 93%). A total of 57 AEs developed. In the 280 mg dose group, grade 3 or higher nonhematologic toxicities, grade 3 type 2 diabetes mellitus, and grade 4 delirium (1/3, 33.3%) developed. In the 560 mg dose group, grade 3 AEs: cholecystitis, periodontitis, pneumonia, soft tissue infection, increased alanine aminotransferase, increased aspartate aminotransferase, and prolonged QT interval, as well as grade 5 urinary tract infection (1/6, 16.7%) developed. DLTs (all of which were grade 3 or higher nonhematologic toxicities) were observed with 1 of 3 pts in the 280 mg dose group (type 2 diabetes mellitus and delirium) and with 2 of 6 pts in the 560 mg dose group (urinary tract infection and prolonged QT interval). Serious AEs were 2 events in 1 of 3 pts in the 280 mg dose group (type 2 diabetes mellitus and delirium) and were 6 events in 3 of 6 pts in the 560 mg dose group (soft tissue infection, periodontitis, cholecystitis, and pneumonia in 1 pt, hematuria in 1 pt, and urinary tract infection in 1 pt). One pt in the 560 mg dose group died of septic shock that had been caused by a urinary tract infection during the study period. The hematological remission rate was 11.1% (1 marrow CR; 1/9 pts), and the hematological improvement rate was 11.1% (1 HI-P; 1/9 pts); however, cytogenetic response was not found. Plasma concentrations of rigosertib increased rapidly after each oral administration. Among the PK parameters, intersubject variability was observed in the maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC). However, changes suggesting the accumulation of rigosertib during repeated oral administration (e.g., consistent increases in the Cmax and AUC) were not found. The urinary excretion rates of rigosertib on day 1 were 1.6 ± 1.0% and 11.0 ± 6.6% (mean ± SD) in the 280 and 560 mg dose groups, respectively. Conclusions: The present chemotherapy regimen of oral rigosertib was well tolerated. Our study indicates that the recommended dose for a Phase II clinical study is 560 mg BID in Japanese patients with recurrent/relapsed or refractory MDS. Disclosures Ishizawa: SymBio Pharmaceuticals: Research Funding. Usuki:Nippon Shinyaku: Honoraria; Sumitomo Dainippon Pharma: Honoraria; MSD: Honoraria; Kyouwa-Kirin: Honoraria; Novartis: Honoraria; Bristol-Myer-Squibb: Honoraria; SymBio Pharmaceuticals: Research Funding. Ando:SymBio Pharmaceuticals: Research Funding. Ueda:SymBio Pharmaceuticals: Research Funding. Uike:SymBio Pharmaceuticals: Research Funding. Onishi:SymBio Pharmaceuticals: Research Funding. Iida:SymBio Pharmaceuticals: Research Funding.

Description: Background: DNA hypomethylating agents, such as 5-azacitidine (5-aza) and decitabine, comprise the current standard in therapy for patients with high-risk myelodysplastic syndromes (MDS), with dramatic responses in some patients. However, the responses are poorly predictable and their impact on clonal dynamics has not been fully elucidated. Patients and Methods: We enrolled a total of 119 patients with high-risk MDS who were treated with 5-aza . Bone marrow samples were collected before (n = 71) and both before and after (n = 48) treatment and analyzed by targeted-capture sequencing using RNA baits designed for 67 known or putative driver genes in myeloid neoplasms and 1,674 single nucleotide polymorphisms, which enabled detection of both mutations and copy number alterations on the same platform. In 9 of the 48 patients, pre- and post-therapy samples were further analyzed by whole exome sequencing (WES). Results: Average number of driver mutations before 5-aza was 2.8 per patient and 107 (90%) patients had multiple mutations. Most frequently mutated were TP53 (27%), followed by RUNX1, TET2, DNMT3A, and ASXL1. Reflecting high-risk disease subtypes of the subjects, splicing factor mutations were relatively rare (29 %) in the current cohort. Chromosomal abnormalities were identified in 65 (55%) patients, where 7q- and /or 5q- were the most frequent. Among 48 patients with serially collected samples, 46 had one or more mutations, enabling an evaluation of clone dynamics. In total 163 and 146 mutations were detected before and after treatment, respectively. About two thirds (110/163) of the mutations before 5-aza remained detectable after treatment. By contrast, the remaining one third showed a dynamic clonal behavior; 36 mutations in 22 cases were newly acquired, whereas 53 in 28 cases disappeared. Among those newly acquired, most frequently observed were mutations in STAG2 and EP300 (n = 3), of which STAG2 (7 cases) also represented the most frequent targets of disappeared mutations after treatment. In WES in 9 patients, a total of 112 mutations were identified either before or after 5-aza treatment with a mean of 10.4 or 8.9 mutations per sample, respectively. Among these, 63 were found at both pre- and post-therapy samples, whereas 17 and 32 mutations were newly acquired or disappeared during treatment, Given that only 4 newly acquired and 8 lost mutations had been detected by targeted-capture sequencing, respectively, WES enabled more sensitive detection of alternation of clones during 5-aza treatment, which were demonstrated in 8 (89%) subjects, rather than 5 (56%) in targeted-capture sequencing. Clinical outcomes have been reported for 22 patients as of the time of abstract submission; 5 achieved complete remission (CR), 9 stable disease (SD), and 5 progressive disease (PD). Alteration in clone size was frequently associated with clinical response. The size of dominant clones significantly decreased in 4 of 5 cases with CR, whereas stable or increased in 12 of 14 patients with SD or PD. In patients with SD or PD, acquisition of new mutations was common (10/14) during 5-aza treatment and potentially implicated in the resistance to 5-aza-treatment. Of interest, newly acquired mutations were also found in 2 CR samples, albeit at low allele frequency, even though the clone size of dominant clones was substantially reduced, suggesting the evolution of alternative MDS subclones or expansion of preexisting non-leukemic hematopoietic clone. Although CR was achieved in 3 of 6 patients with TP53 mutations, the TP53-mutationsdid not totally disappeared but were still detectable in CR samples in 2 cases, suggesting that TP53 mutated clones have not been completely eradicated by 5-aza treatment. Conclusion: Our study successfully depicted the structure of clones and their dynamics in high-risk MDS on 5-aza treatment. Alteration in the size of the dominant clones was frequently associated with a clinical response. Clonal evolution was common even in patients who achieved CR. Tracking the mutations in MDS patients during 5-aza treatment provides the opportunity to detect clones resistant to 5-aza and might be used to guide 5-aza therapy. Disclosures Kataoka: Kyowa Hakko Kirin: Honoraria; Boehringer Ingelheim: Honoraria; Yakult: Honoraria. Kiyoi:Celgene Corporation: Consultancy; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; JCR Pharmaceutlcals Co.,Ltd.: Research Funding; AlexionpharmaLLC.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Toyama Chemikal Co.,Ltd.: Research Funding; Mochida Pharmaceutical Co., Ltd.: Research Funding; Novartis Pharma K.K.: Research Funding; Alexion Pharmaceuticals: Research Funding; MSD K.K.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding; Phizer Japan Inc.: Research Funding; Yakult Honsha Co.,Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; Fujifilm Corporation: Patents & Royalties, Research Funding; Zenyaku Kogyo Co.LTD.: Research Funding; Kyowa-Hakko Kirin Co.LTD.: Research Funding; Chugai Pharmaceutical Co. LTD.: Research Funding. Naoe:Sumitomo Dainippon Pharma Co.,Ltd.: Honoraria, Research Funding; Chugai Pharmaceutical Co.,LTD.: Honoraria, Patents & Royalties; Astellas Pharma Inc.: Research Funding; Kyowa-Hakko Kirin Co.,Ltd.: Honoraria, Patents & Royalties, Research Funding; TOYAMA CHEMICAL CO.,LTD.: Research Funding; Amgen Astellas BioPharma K.K.: Honoraria; Bristol-Myers Squibb: Honoraria; Celgene K.K.: Honoraria, Research Funding; CMIC Co., Ltd.: Research Funding; Fujifilm Corporation: Honoraria, Patents & Royalties, Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Honoraria, Research Funding; Otsuka Pharmaceutical Co.,Ltd.: Honoraria, Research Funding; Pfizer Inc.: Research Funding. Makishima:The Yasuda Medical Foundation: Research Funding. Ogawa:Sumitomo Dainippon Pharma: Research Funding; Kan research institute: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy, Research Funding.

Description: Background: Studies on germline variants responsible for cancer predisposition provide an important clue to the understanding of genetic basis of cancer and also help better prediction and management of relevant cancers. As for myeloid neoplasms, only a handful of genes, including RUNX1, CEBPA, GATA2, ETV6, and ANKRD26, have been implicated in early onset familial acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), although they are rarely seen in sporadic cases. Recently, using whole exome sequencing of familial AML/MDS, we have reported novel AML/MDS predisposing gene, DDX41, an encoding dead-box helicase gene. Conspicuously, the onset of AML/MDS was over 60 in most of the affected cases, raising a possibility that the genetic predisposition might be obscured and many cases could be diagnosed with sporadic AML/MDS. In this study, we investigated germline DDX41 mutations in sporadic cases with AML/MDS and the incidence and mutation types were compared between Asian and Western patients. Patients and Methods: We performed targeted sequencing of DDX41 in patients from Asian (N = 239) cohort of AML/MDS, where the origin of the detected variations was determined by using matched germline DNA. The result was compared to those obtained from the Western cohort (N = 1,034) in terms of frequency and type of mutation. The effect size of the mutations was estimated by calculating odds ratios of each variant for AML/MDS development using the data for DDX41 variants in Asian and Western population from the ExAC (Exome Aggregation Consortium) database (http://exac.broadinstitute.org) as controls. Results: Germline and somatic DDX41 mutations were found in 12 (5.0%) and 10 (4.7%) of sporadic cases with AML/MDS from the Asian cohort, as compared to 8 (0.8%) and 10 (1.0%) from the Western cohort. All the patients with germline variants were aged over 40 year-old with a median of 68.5, confirming the late onset of the disease also in the sporadic cases with germline variants. Eight of the 12 germline variants (67%) in the Asian cohort were accompanied by an additional somatic mutation, as compared to 2 of the 8 (25%) in the Western cohort. Biallelic involvement was demonstrated in selected cases (N = 2). In total, 8 and 3 germline variants were observed in the Asian and the Western cohorts, respectively, without no common variants between both cohorts, of which the predominant variants included p.A500fs (n=5; 42%) and p.E7X (n=2; 17%) in the Asian cohort and p.F140fs (n=6; 75%) in Western cohort. In contrast, a prominent hotspot mutation involving a highly conserved amino-acid within the helicase domain (p.R525H) was commonly observed in both cohorts, accounting for 55% of all the somatic mutations. These germline variants as a whole showed significant enrichment in AML/MDS cases compared to the respective control population (OR〉171, 95% confidence interval (CI): 51-730 for the Asian variants and more than 21.7, 95%CI: 8.4-50 for the Western variants), although the enrichment of individual variants showed substantial variations, suggesting different effect size among these variants: the odds ratio was 19.5 (p

Description: DNA hypermethylation has long been implicated in the pathogenesis of myelodysplastic syndromes (MDS) and also highlighted by the frequent efficacy of demethylating agents to this disease. Meanwhile, recent genetic studies in MDS have revealed high frequency of somatic mutations involving epigenetic regulators, suggesting a causative link between gene mutations and epigenetic alterations in MDS. The accumulation of genetic and epigenetic alterations promotes tumorigenesis, hypomethylating agents such as Azacitidine exert their therapeutic effect through inhibition of DNA methylation. However, the relationship between patterns of epigenetic phenotypes and mutations, as well as their impact on therapy, has not been clarified. To address this issue, we performed genome-wide DNA methylation profiling (Infinium 450K) in combination with targeted-deep sequencing of 104 genes for somatic mutations in 291 patients with MDS. Beta-mixture quantile normalization was performed for correcting probe design bias in Illumina Infinium 450k DNA methylation data. Of the 〉480,000 probes on the methylation chip, we selected probes using the following steps: (i) probes annotated with "Promotor_Associated" or "Promoter_Associated_Cell_type_specific; (ii) probes designed in "Island", "N_Shore" or "S_Shore"; (iii) removing probes designed on the X and Y chormosomes; (iv) removing probes with 〉10% of missing value. Consensus clustering was performed utilizing the hierarchical clustering based on Ward and Pearson correlation algorithms with 1000 iterations on the top 0.5% (2,000) of probes showing high variation by median absolute deviation across the dataset using Bioconductor package Consensus cluster plus. The number of cluster was determined by relative change in area under cumulative distribution function curve by consensus clustering. Unsupervised clustering analysis of DNA methylation revealed 3 subtypes of MDS, M1-M3, showing discrete methylation profiles with characteristic gene mutations and cytogenetics. The M1 subtype (n=121) showed a high frequency of SF3B1 mutations, exhibiting the best clinical outcome, whereas the M2 subtype (n=106), characterized by frequent ASXL1, TP53 mutations and high-risk cytogenetics, showed the shortest overall survival with the hazard ratios of 3.4 (95% CI:1.9-6.0) and 2.2 (95% CI:1.2-4.0) compared to M1 and M3, respectively. Finally, the M3 subtype (n=64) was highly enriched (70% of cases) for biallelic alterations of TET2 and showed the highest level of CpG island methylation and showed an intermediate survival. In the current cohort, we had 47 patients who were treated with demethylating agents, including 11 responders and 36 non-responders. When DNA methylation status at diagnosis was evaluated in terms of response to demethylating agents, we identified 54 differentiated methylated genes showing 〉20% difference in mean methylation levels between responders and non-responders (q 〈 0.1). Twenty-five genes more methylated in responders were enriched in functional pathways such as chemokine receptor and genes with EGF-like domain, whereas 29 less methylated gene in responders were in the gene set related to regulation of cell proliferation. Genetic alterations were also assessed how they affected treatment responses. In responders, TET2 mutated patients tended to more frequently respond (45% vs 34%), whereas patients with IDH1/2 and DNMT3A mutations were less frequently altered (0% vs 14%, 9% vs 14%) in responders, compared in non-responders. In conclusion, our combined genetic and methylation analysis unmasked previously unrecognized associations between gene mutations and DNA methylation, suggesting a causative link in between. We identified correlations between genetic/epigenetic profiles and the response to demethylating agents, which however, needs further investigation to clarify the mechanism of and predict response to demethylation agents in MDS. Disclosures Alpermann: MLL Munich Leukemia Laboratory: Employment. Nadarajah:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kiyoi:Taisho Toyama Pharmaceutical Co., Ltd.: Research Funding; Novartis Pharma K.k.: Research Funding; Pfizer Inc.: Research Funding; Takeda Pharmaceutical Co.,Ltd.: Research Funding; MSD K.K.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Alexion Pharmaceuticals.: Research Funding; Teijin Ltd.: Research Funding; Zenyaku Kogyo Company,Ltd.: Research Funding; FUJIFILM RI Pharma Co.,Ltd.: Patents & Royalties, Research Funding; Nippon Shinyaku Co.,Ltd.: Research Funding; Japan Blood Products Organization.: Research Funding; Eisai Co.,Ltd.: Research Funding; Yakult Honsha Co.,Ltd.: Research Funding; Astellas Pharma Inc.: Consultancy, Research Funding; Kyowa-Hakko Kirin Co.,Ltd.: Consultancy, Research Funding; Fujifilm Corporation.: Patents & Royalties, Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Bristol-Myers Squibb.: Research Funding; Chugai Pharmaceutical Co.,LTD.: Research Funding; Mochida Pharmaceutical Co.,Ltd.: Research Funding. Kobayashi:Gilead Sciences: Research Funding. Naoe:Toyama Chemical CO., LTD.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Nippon Boehringer Ingelheim Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Patents & Royalties, Research Funding; Pfizer Inc.: Research Funding; Astellas Pharma Inc.: Research Funding; FUJIFILM Corporation: Patents & Royalties, Research Funding; Celgene K.K.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Patents & Royalties. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Miyazaki:Chugai: Honoraria, Research Funding; Shin-bio: Honoraria; Sumitomo Dainippon: Honoraria; Celgene Japan: Honoraria; Kyowa-Kirin: Honoraria, Research Funding.

Description: Background Azacitidine (AZA) is one of the hypomethylating agents (HMAs) proven to significantly prolong overall survival (OS) for patients with higher-risk myelodysplastic syndromes (h-MDS) via a prospective phase 3 trial. However, the optimal treatment schedule of AZA for h-MDS has not yet been prospectively determined. As a 7-day treatment schedule includes weekends, a 5-day administration has also been applied with h-MDS, though solid evidence has not been established. Based on this background, we planned to compare AZA treatment on 7-day and 5-day schedules. Patients Patients diagnosed with de novo or treatment-related MDS (FAB-defined RAEB and RAEB-t), aged 16 years or older were eligible for this study, if they showed adequate performance status (ECOG PS 0-2) and no history of HMA treatment or chemotherapy. Candidates for allogeneic stem-cell transplantation were excluded. Study design This was a multicenter, randomized, open-label, phase 3 trial to compare the efficacy of AZA treatment for 7-days (AZA-7) to 5-days (AZA-5). The primary endpoint was 2-year OS rate (2y OS). AZA was given subcutaneously at 75 mg/m² every 28 days. To test the non-inferiority of AZA-5 to AZA-7, 2y OS of AZA-7 was estimated at 30%, and the delta was defined as 11%, for which 410 patients were needed to complete the trial. However, because of the poor recruitment, this study closed prematurely, and the protocol-planned interim analysis (when 200 patients were registered) was performed. This protocol was approved by the IRB at each trial center. All patients provided written informed consent, and the trial was conducted in accordance with the Declaration of Helsinki. The efficacy of AZA was evaluated using IWG2006 criteria, and treatment was continued until study completion, or relapse, unacceptable toxicity, or disease progression was observed. Efficacy was analyzed by intention-to-treat. Secondary endpoints were the hematological response rate, 2-year leukemia-free survival (2y LFS) rate, the cytogenetic response, and occurrence of adverse events. Results Between January 2013 and Jun 2018, 201 patients were randomly assigned to AZA-7 (n=99) or AZA-5 group (n=102). The median age of all patients at the enrollment was 73.5 years old (range, 48 to 91). Between the two groups, there was no significant difference in the baseline characteristics, such as sex, type of MDS (de novo or treatment-related), percent of BM blasts, FAB and WHO classification, and IPSS and IPSS-R risk. After excluding 5 and 6 patients from AZA-7 and AZA-5, respectively (poor data entry, change in diagnosis), at the time of last follow-up, 59 and 67 patients died in AZA-7 and AZA-5, respectively. The Kaplan-Meier estimates of the 2y OS and 2y LFS were 35.1% (95% CI, 23.8 to 46.7) and 27.3% (95% CI, 17.3 to 38.3) for AZA-7, and 22.4% (95% CI, 13.1 to 33.3) and 20.5% (95% CI, 11.6 to 31.2) for AZA-5, respectively. There was no significant difference in the frequency of erythroid, platelet or neutrophil improvement, or hematological response (complete or partial response, or any hematological improvement) between the two groups. The most common non-hematological adverse event of grade 3 to 4 (in ≥20% of the patients in either group) was febrile neutropenia (33.7% for AZA-7, and 30.5% for AZA-5). Conclusion and Discussion Because of the premature termination of this trial, statistical analysis for the primary endpoint (2y OS of 35.1% for AZA-7, and 22.4% for AZA-5) could not provide any solid evidence. However, considering the difference of more than 10% in 2y OS, and no major differences in the safety profiles, we favor AZA-7 to AZA-5 for MDS patients with RAEB and RAEB-t. Figure Disclosures Kiguchi: Tejin Co., Ltd.: Research Funding; Taiho Pharmaceutical Co., Ltd.: Research Funding; SymBio Pharmaceutical Co., Ltd.: Research Funding; Celgene Co., Ltd.: Research Funding; Janssen Pharmaceutical Co., Ltd.: Research Funding; Sumitomo Dainippon Pharmaceutical Co., Ltd.: Research Funding; Novartis Pharmaceutical Co., Ltd.: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; Astellas Pharmaceutical Co., Ltd.: Research Funding; MSD CO., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Bristol-Myeres Squibb Co., Ltd.: Research Funding; Sanofi K.K., Ltd.: Research Funding; Celltrion, Inc.: Research Funding. Usuki:Daiichi Sankyo Co., Ltd.: Research Funding, Speakers Bureau; Astellas Pharma Inc: Research Funding, Speakers Bureau. Suzuki:kyowa Hakko Kirin: Consultancy, Honoraria; MSD k.k.: Research Funding; Nippon Shinyaku: Honoraria; Novartis: Honoraria; takeda: Research Funding; Incyte and Pfizer: Research Funding; astellas: Research Funding; Celgene: Honoraria; Chugai: Honoraria, Research Funding; daiichi sankyo: Research Funding; eisai: Research Funding. Tomita:Chugai Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Kyowa Kirin: Research Funding; Taiho Pharma: Research Funding. Handa:Ono: Research Funding. Maeda:Janssen Pharmaceutical K.K..: Honoraria; Nippon Shinyaku Co., Ltd.: Honoraria. Iyama:Otsuka Pharmaceutical Co., Ltd.: Honoraria; Otsuka Pharmaceutical Factory: Honoraria; Astellas Pharma: Honoraria; Daiichi Sankyo: Honoraria; Allexion Pharma: Honoraria; CSL Behring: Honoraria. Yamauchi:Astellas, AbbVie: Consultancy; Pfizer, Chugai, Teijin, Solasia: Research Funding. Kiyoi:Daiichi Sankyo Co., Ltd: Research Funding; Bristol-Myers Squibb: Research Funding; Pfizer Japan Inc.: Honoraria; Nippon Shinyaku Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co.,Ltd.: Research Funding; Perseus Proteomics Inc.: Research Funding; FUJIFILM Corporation: Research Funding; Astellas Pharma Inc.: Honoraria, Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Takeda Pharmaceutical Co., Ltd.: Research Funding. Miyazaki:Chugai: Research Funding; Otsuka: Honoraria; Novartis: Honoraria; Nippon-Shinyaku: Honoraria; Dainippon-Sumitomo: Honoraria; Kyowa-Kirin: Honoraria.

Description: Background: Recent advance in genetic analysis has revealed that many mutations are associated with the development, progression and/or prognosis of core-binding factor acute myeloid leukemia (CBF-AML). Although KIT mutation is the most frequently identified in CBF-AML, its prognostic relevance remains controversial. We conducted the prospective, multicenter cooperative study (JALSG CBF-AML209-KIT, UMIN Clinical Trials Registry UMIN000003434, http://www.umin.ac.jp/ctr/) to evaluate the prognostic impact of KIT mutation, the incidence and clinical relevance of the other gene mutations and prognostic impact of the minimal residual disease (MRD) in CBF-AML. Methods: A total of 199 patients 16 to 64 years of age with newly diagnosed de novo AML were enrolled in this study if they had a RUNX1-RUNX1T1 or CBFB-MYH11 chimeric transcript and achieved complete remission within 2 courses of the standard induction therapies consisting of cytarabine and either daunorubicin or idarubicin. All patients were to be received 3 courses of high-dose cytarabine therapy (2 g/m2 by 3-hour infusion every 12 hours for 5 days) and no further chemotherapy until relapse. MRD level was evaluated in BM after the completion of the 3-course of consolidation therapy by the quantitation of RUNX1-RUNX1T or CBFB-MYH11 transcript in 112 patients. Target sequencing of 56 genes frequently identified in myeloid malignancies including exons 8, 10, 11 and 17 of the KIT gene were analyzed using the preserved DNA extracted from AML cells at diagnosis. Results: A total of 68 KIT mutations were identified in 63 of 199 patients (31.7%); 42 of 132 (31.8%) and 21 of 67 (31.3%) patients with RUNX1-RUNX1T1 and CBFB-MYH11, respectively. Mutation in exon 17 was the most frequently identified (73.5%), followed by in exon 8 (20.6%) and in exon 10-11 (5.9%). Mutation in exon 8 was more frequent in AML with CBFB-MYH11 (37.5%) than that with RUNX1-RUNX1T1 (11.4%, P=0.014). Although mutation at N822 residue in exon 17 was identified in 13/44 (29.5%) KIT mutations of the patients with RUNX1-RUNX1T1, no patient with CBFB-MYH11 had this mutation (P=0.008); however, mutation at the D816 residue was equally identified in patients with RUNX1-RUNX1T1 (21/44, 47.7%) and CBFB-MYH11 (13/24, 54.1%). The median BM blast percentage of the KIT mutation positive-patients (73.5%) was significantly higher than that of negative-patients (53.8%, P