ALBERT

Description: Key Points BMI1 overexpression is one of the second hit partner genes of RUNX1 mutations that contribute to the development of MDSs.

Description: Background: Autologous stem cell transplantation (ASCT) combined with novel therapeutic drugs, including proteasome inhibitors (PIs)/immunomodulatory agents (IMiDs), can substantially improve the prognosis of patients with multiple myeloma (MM). Because MM patients survive longer, the incidence of secondary primary malignancies (SPMs) in long-term survivors is increasing. To date, only few studies have evaluated SPMs in real-world patients, particularly in those with MM in Asia. Aims: To analyze the risk factors of SPMs in MM patients after ASCT before and after the introduction of PIs/IMiDs. Methods: In this retrospective observational study, data from the Registry of the Japan Society for Hematopoietic Cell Transplantation were collected and analyzed. A total of 2340 newly diagnosed MM patients who underwent ASCT between 1993 and 2016 were enrolled in this study. Median age 58 at ASCT (range 22-72); males 1329 (56.8%), females 1011 (43.2%); IgG 1340 (57.3%), IgA 452 (19.3%), IgD 63 (2.7%), IgE 3 (0.1%), IgM 6 (0.3%), BJP 416 (17.8%), non-secreting 38 (1.6%), unknown 22 (0.9%); ISS1 774 (33.1%), ISS2 825 (35.3%), ISS3 455 (19.4%), not assessed 286 (12.2%). 1908 (81.5%) and 432 (18.5%) patients received single melphalan 200 mg/sqm (Mel200) and double Mel200, respectively as conditioning regimen before ASCT. Moreover, 771 (32.9%) and 1569 (67.1%) patients underwent ASCT from 1993 to 2006 and from 2007 to 2016, respectively. 659 (28.2%) patients received PIs, 73 (3.1%) IMiDs and 903 (38.6%) both PIs and IMiDs. Meanwhile, 38 (1.6%) patients received radiation treatment. The disease status at ASCT was as follows: 690 (29.5%), sCR/CR; 580 (24.8%), VGPR; 831 (35.5%), PR; 144 (6.2%), SD; 50 (2.1%), PD; and 45 (1.9%), unknown. Results: The median follow-up from ASCT was 24 (range: 0-218) months. A total of 38 patients in this cohort developed SPMs, with a cumulative incidence of 0.8% [95% confidence interval (CI): 0.4%-1.2%] and 2.4% (95% CI: 1.6%-3.5%) at 24 and 60 months, respectively. Twenty-four solid (4, stomach; 3, breast; 5, lung; 2, liver; 2, pancreas; 2, colon; 1, uterus; 1, thyroid gland; 1, bladder; 2, sarcoma; and 1, basal cell carcinoma), 11 hematologic (7, myelodysplastic syndrome; 1, acute leukemia; 2, lymphoma; and 1, unknown), and 3 unknown tumors were observed. The cumulative incidence of hematologic and solid SPMs at 60 months was 0.8% and 1.7%, respectively. OS at 60 months after ASCT was 62.9%, and OS after the diagnosis of SPMs at 24 months was 70.7% for hematologic and 64.6% for solid SPMs (median follow-up of 23 months). Next, the risk factors affecting the incidence of SPMs were analyzed, which included age at ASCT (≤65 or 〉65 years), sex, PI/IMiD treatment, use of radiation, single/double ASCT, and period of ASCT (1993-2006 or 2007-2016). Because bortezomib, thalidomide, and lenalidomide were released for relapse/refractory MM treatment in Japan in December 2006, February 2009, and July 2010, respectively, we categorized the patients into two treatment cohorts: pre-novel agent era (1993-2006) and novel agent era (2007-2016). Univariate analysis showed that the novel agent era (1.7% vs 4.3% at 60 months; P = 0.013; Fig. 1) and use of radiation (2.3% vs 9.5% at 60 months; P = 0.027) were significant independent risk factors for SPMs. Multivariate analysis revealed that the use of radiation [hazard ratio (HR): 3.895; 95% CI: 1.163-13.050; P = 0.027] was a significant, independent risk factor for SPMs. The novel agent era (HR: 1.716; 95% CI: 0.857-3.438; P = 0.13) and IMiD without PI treatment (HR: 2.206; 95% CI: 0.787-6.189; P = 0.13) were likely high-risk factors for SPMs. In contrast, PI without IMiD treatment (P = 0.79) was not a risk factor for SPMs. The probabilities of developing SPMs and death due to other causes (mainly MM) at 60 months were 2.4% and 36.5% (Fig. 1), respectively, indicating that the risk for SPMs was lower than that for death from MM. Furthermore, OS between the pre-novel and novel agent era groups significantly improved (59.2% vs. 69.5%, P 〈 0.0001) at 60 months after ASCT. Conclusions: The incidence of SPMs in patients with MM in Japan was consistent with that reported recently (Sahebi et al. BBMT, 2018). Although the risk for SPMs increased in the novel agent era group, the mortality rate of SPMs was lower than that of other causes (primarily MM). Considering the increase in the number of long-term survivors with MM, the early occurrence of SPMs should be cautiously monitored. Disclosures Takamatsu: Bristol-Myers Squibb: Honoraria, Research Funding; Ono pharmaceutical: Honoraria, Research Funding; CSL Behring: Research Funding; SRL: Consultancy, Research Funding; Daiichi-Sankyo Company: Honoraria; Becton, Dickinson and Company: Honoraria; Sanofi: Consultancy, Honoraria; Takeda Pharmaceutical Company Limited: Honoraria; Fujimoto Pharmaceutical: Honoraria; Janssen Pharmaceutical: Consultancy, Honoraria; Abbvie: Consultancy; Celgene: Consultancy, Honoraria, Research Funding. Mizuno:Takeda Pharmaceutical Co., Ltd.: Honoraria; Bristol-Myers Squibb Corporation: Honoraria; Celgene Corporation: Honoraria; Nippon Shinyaku Co., Ltd.: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Honoraria. Fuchida:Japan Blood Products Organization: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Daiichi-Sankyo Company: Honoraria; Celgene: Honoraria; Bristol-Myers Squibb: Honoraria; Ono pharmaceutical: Honoraria; Kyowa Kirin: Honoraria; SEKISUI MEDICAL CO., LTD.: Honoraria; Takeda Pharmaceutical Company Limited: Honoraria. Hanamura:Asai Clinic: Research Funding; Yamada Yohojo: Research Funding; AbbVie: Honoraria; Chugai: Research Funding; Eli Lilly: Research Funding; Taiho: Research Funding; Sanofi: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Astellas: Research Funding; Pfizer: Honoraria, Research Funding; Eisai: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Fukuyu Hospital: Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Nihon Shinyaku: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Shionogi: Honoraria, Research Funding; Fujimoto: Research Funding; MSD: Research Funding; Zenyaku: Research Funding; Ono: Consultancy, Honoraria, Research Funding; Kyowa Kirin: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Mundi: Honoraria. Nakamura:Astellas Pharma Inc.: Honoraria; Takeda Pharmaceutical Company Limited: Research Funding; Eisai Co. Ltd.: Honoraria; Kyowa Kirin: Research Funding. Mori:Celgene: Honoraria; Takeda Pharmaceutical Company Limited: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Bristol-Myers Squibb: Honoraria; Ono Pharmaceutical: Honoraria; Novartis Pharma K.K: Honoraria. Tsukada:Chugai Pharmaceutical Co.,Ltd: Honoraria; Kyowa Kirin: Honoraria; Celgene: Honoraria; Ono Pharmaceutical: Honoraria; Sanofi: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria; MOCHIDA PHARMACEUTICAL CO., LTD.: Honoraria; Asahi Kasei Pharma Corporation: Honoraria; Ohtsuka Pharmaceutical: Honoraria; Fujimoto Pharmaceutical: Honoraria. Ichinohe:Astellas Pharma: Research Funding; Chugai Pharmaceutical Co.: Research Funding; CSL Behring: Research Funding; Eisai Co.: Research Funding; Kyowa Hakko Kirin Co.: Research Funding; Ono Pharmaceutical Co.: Research Funding; Pfizer: Research Funding; Nippon Shinyaku Co.: Research Funding; MSD: Research Funding; Otsuka Pharmaceutical Co.: Research Funding; Repertoire Genesis Inc.: Research Funding; Sumitomo Dainippon Pharma Co.: Research Funding; Taiho Pharmaceutical Co.: Research Funding; Takeda Pharmaceutical Co.: Research Funding; Zenyaku Kogyo Co.: Research Funding; Alexion Pharmaceuticals: Honoraria; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; JCR Pharmaceuticals: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Mundipharma: Honoraria; Novartis: Honoraria. Kanda:Pfizer: Research Funding; Novartis: Research Funding; Mochida: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Nippon-Shinyaku: Research Funding; Chugai: Consultancy, Honoraria, Research Funding; Shionogi: Consultancy, Honoraria, Research Funding; Ono: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Nippon-Shinyaku: Research Funding; Ono: Consultancy, Honoraria, Research Funding; Eisai: Consultancy, Honoraria, Research Funding; CSL Behring: Research Funding; Kyowa-Hakko Kirin: Consultancy, Honoraria, Research Funding; Asahi-Kasei: Research Funding; Tanabe Mitsubishi: Research Funding; Novartis: Research Funding; Kyowa-Hakko Kirin: Consultancy, Honoraria, Research Funding; Shionogi: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Chugai: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria; Takara-bio: Consultancy, Honoraria; Tanabe Mitsubishi: Research Funding; Asahi-Kasei: Research Funding; MSD: Research Funding; Alexion: Consultancy, Honoraria; Takara-bio: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; Mochida: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Pfizer: Research Funding; CSL Behring: Research Funding; MSD: Research Funding; Otsuka: Research Funding; Eisai: Consultancy, Honoraria, Research Funding; Dainippon Sumitomo: Consultancy, Honoraria, Research Funding; Otsuka: Research Funding; Sanofi: Research Funding; Dainippon Sumitomo: Consultancy, Honoraria, Research Funding; Taisho-Toyama: Research Funding; Sanofi: Research Funding; Taiho: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Taisho-Toyama: Research Funding; Celgene: Consultancy, Research Funding; Taiho: Research Funding. Atsuta:CHUGAI PHARMACEUTICAL CO., LTD.: Honoraria; Kyowa Kirin Co., Ltd: Honoraria. Sunami:Takeda: Honoraria, Research Funding; GSK: Research Funding; Sanofi: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding; Ono: Honoraria, Research Funding; Alexion-pharma: Research Funding; Daiichi Sankyo: Research Funding; MSD: Research Funding; Abbvie: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Research Funding.

Description: Introduction: We have recently reported that the evaluation CD25 expression on leukemic blasts at the time of disease onset could be an alternative non-molecular tool for predicting transplant outcomes in patients with cytogenetically intermediate acute myeloid leukemia (AML). We herein focus on patients with refractory or relapsed AML and examine the clinical correlation of the surface CD25 expression measured by flow cytometry at the time of transplantation and subsequent transplant outcomes. Patients and methods: A total of 60 AML samples with primary induction failure (n = 32), first relapse (n = 23) or second relapse (n = 5) were analyzed by means of flow cytometric CD25 antigen expression on leukemic blasts at the time of transplantation. Survival outcomes were compared with regard to the CD25 expression. Overall survival (OS) and progression-free survival (PFS) were estimated by Kaplan-Meiyer. Factors associated with at least borderline significance (p〈 0.10) on univariate analyses were subjected to multivariate analysis using backward stepwise proportional hazard modeling. Multivariate analysis was performed using the Cox proportional hazards regression model. Results: CD25 antigen expression (〉10%) on leukemic blasts was observed in 24 patients (40%). There was no significant difference between CD25 positive and negative groups in terms of clinical characteristics including cytogenetic risk, WHO classification, marrow or peripheral blasts % at transplantation, comorbidity, conditioning regimen, donor source or interval between diagnosis and transplantation. Although more early relapse cases within 180 days were observed in the CD25 positive group (p = 0.01), cumulative incidence of relapse, non-relapse mortality, acute or chronic graft-versus-host disease were not different between 2 groups. However, there was a significant difference in OS or PFS between 2 groups: 2-years OS; 8.3% vs. 34.0%, p=0.004 (Fig 1A), 2-years PFS; 8.3% vs. 26.3%, p=0.003 (Fig 1B). Moreover, multivariate analysis showed that CD25 expression was an independent adverse factor for OS (hazard ratio: 2.01, 95% confidence interval: 1.10-3.67, p = 0.02). Conclusion: Our cohorts with total 60 patients with refractory or relapsed AML showed that CD25 endowed these patients with an adverse prognostic impact, which might not be overcome even by transplantation. AML patients with residual CD25+ blasts at the time of transplantation might require additional therapy before or after transplantation for better survival. However, our small experience clearly desires larger series patients for evaluating the real impact of CD25 expression. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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: Acute lymphoblastic leukemia (ALL) is one of the most frequently occurring cancers in infants and young children. For patients suffering from CD20-positive B-cell ALL (B-ALL) and Ph-positive ALL, overall survival rates have been greatly improved after clinical introduction of rituximab and imatinib, respectively. However, T-cell ALL (T-ALL) patients still exhibit poor prognosis, since there is no such an efficient molecular-targeted drug. It is known that LIM-only transcriptional co-factor LMO2 and its target gene HHEX are essential for self-renewal of T cell precursors and onset of T-ALL. LMO2 directly associates with LDB1 in a large DNA-containing nuclear complex and controls the transcription of T-ALL-related downstream genes. Recently, we reported that overexpression of LIM-homeodomain transcription factor Lhx2 results in liberation of Lmo2 protein from the Lmo2-Ldb1 complex followed by degradation by ubiquitin-proteasome system. We found that proliferation of 5 different human T-ALL-derived cell lines including CCRF-CEM was significantly suppressed by retroviral overexpression of Lhx2. In contrast, enforced overexpression of Lhx2 did not reduce the growth rate of B lymphoma-derived cell line Raji, oral cancer-derived cell line HSC-3, and osteosarcoma-derived cell line Saos-2. Majority of the Lhx2-transduced CCRF-CEM cells was arrested in G0 phase and subsequently underwent apoptosis. Expression of LMO2 protein and HHEX mRNA was repressed by the Lhx2 transduction. Importantly, the Lhx2-mediated growth inhibition was partially rescued by the simultaneous overexpression of Lmo2. However, both C-terminal LIM-domain and homeodomain of Lhx2 were required for the growth-suppressive activity. These data indicated that Lhx2 is capable to blocking proliferation of T-ALL-derived cells in LMO2-dependent and independent fashions. Lhx2 would be a useful molecular tool for designing a new type of anti-T-ALL drug. In order to develop a new drug that mimics the aforementioned activity of Lhx2, we performed large-scale screening of natural compound libraries to find out a compound that suppresses the proliferation of T-ALL cell line CCRF-CEM, but does not inhibit the growth of B lymphoma cell line Raji. Among 150,000 different compounds, we successfully identified 3 low-molecular-weight compounds (44D-L008, 31D-F005, 21D-D016) that fulfilled the above criteria. 44D-L008 and 31D-F005 possessed a common chemical structure. In the presence of 5μM of 44D-L008 and 31D-F005, proliferation of 5 human T-ALL cell lines including CCRF-CEM was severely blocked. On the other hand, Raji, HSC-3 and Saos-2 were completely resistant to both compounds in the same experimental settings. Intriguingly, 44D-L008 decreased viability of human skin fibroblasts in culture, whereas 31D-F005 displayed no such negative effects on skin fibroblasts, peripheral blood mononuclear cells, and peripheral blood T cells of human origin. These results indicated that small differences in the chemical structure between 44D-L008 and 31D-F005 are responsible for the side effect on normal cells. Finally, we collaborated with a hospital and found that 0.5 μM of 31D-F005 efficiently suppressed the in vitro growth of primary cancer cells of a T-ALL patient. Taken together, theses data demonstrated that 31D-F005 is a promising lead compound for a new anti-T-ALL drug. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 2820 RUNX1/AML1 mutations have been frequently detected in patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). RUNX1 mutations are rarely detected in lower-risk MDS, whereas approximately 20% patients with higher-risk MDS (H-MDS) have the mutations. The mutations were distributed throughout the RUNX1 protein, and replacement of D171 amino acid in runt homology domain was the most frequent target of mutations in the RUNX1 gene. The D171N mutant showed a loss of normal RUNX1 trans-activation potential and dominant-negative suppression. In mouse transplantation systems D171N-transduced mice exhibited AML with multilineage dysplasia in collaboration with Evi1 overexpression. However, EVI1 overexpression was very rare in patients. Instead, most of H-MDS patients with RUNX1 mutations displayed a high expression of BMI1. RUNX1 D171N mutant showed an increased self-renewal capacity, differentiation block, dysplasia in all 3 lineages, slightly increased immature cells and no proliferation ability using enforced expression in human CD34+ cells, and the D171N-transduced cells showed low expression level of BMI1. Both D171N and BMI1 transduced cells displayed long-term proliferation ability. When BMI1 transduced later into D171N cells, the cells expanded with a retained CD34+ cell fraction, suggesting that BMI1 have a potential to boost the D171N cells to H-MDS. To confirm the collaboration of BMI1 overexpression with D171N mutant in vivo, we performed mouse BMT using BM cells transduced with both D171N and BMI1. Ly-5.1 murine BM mononuclear cells infected with retrovirus harboring D171N/BMI1 or control vectors were transplanted into sublethally irradiated syngeneic Ly-5.2 mice. Mice that received transplants of BMI1-transduced cells remained healthy over the observation period (n=12/12), as well as those that were transplanted with empty vectors-transduced cells (n=4/4). Most of the mice that received transplants of D171N -transduced cells developed MDS/AML mainly 6–8 months after transplantation (n=6/11, P

Description: 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 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

Description: Introduction: Acute myeloid leukemia (AML) with chromosomal translocation t(7;11)(p15;p15) [t(7;11)], which results in a fusion between NUP98 and HOXA9, is uncommon, and classified as intermediate risk (IR) in National Comprehensive Cancer Network (NCCN) Guidelines. Previous studies have reported that the patients with AML harboring t(7;11) exhibited a worse clinical outcome than the other AML groups. These reports included mostly patients who underwent chemotherapy rather than allogeneic hematopoietic stem cell transplantation (allo-HSCT), and the number of patients in each study was very small. Moreover, the transplant outcomes of patients with AML harboring t(7;11) compared to patients with other AML have not been reported. Therefore, we investigated the transplant outcomes among 91 patients with AML harboring t(7;11) compared to the patients with IR (n=7,308) and poor risk (PR) (n=2,406) AML, except for t(7;11). Moreover, we evaluated the risk factors for survival in patients with AML harboring t(7;11) who underwent allo-HSCT. Patients and Methods: During 1997 and 2014, 91 patients with AML harboring t(7;11) were identified from the nationwide registration data of the Japan Society for Hematopoietic Cell Transplantation. Cytogenetic risk group stratification was performed using the NCCN guidelines for AML in 2016. Univariate and multivariate analysis for survival were performed in all patients cohort and only among patients with AML harboring t(7;11). Univariate models for overall survival (OS) and disease-free survival (DFS) included age at allo-HSCT (age 55 ≥ years vs. 55 〈 years), sex, performance status (PS) (2-4 vs. 0-1), the hematopoietic cell transplantation-comorbidity index (0-2 vs. ≥ 3), additional chromosomal change, disease status at allo-HSCT (first complete remission [CR]: CR1 vs. second CR:CR2 or non-CR at allo-HSCT), conditioning regimen (total body irradiation [TBI] ≥ 8Gy vs. others), and stem cell source (related donor vs. cord blood or unrelated donor). Factors associated with at least borderline significance (p 〈 0.20) on univariate analyses were subjected to multivariate analysis. Results: Patient Characteristics We evaluated the clinical characteristics of patients with t(7;11), IR, and PR.The median follow-up period for survivors was 1,124 days (range, 1-8,758). Patients with t(7;11) were younger (median age: 45 vs. 48 vs. 50 years, p

Description: Introduction In allogeneic stem cell transplantation (allo-SCT), recent reports have shown that post-transplant microbial diversity of the gastrointestinal tract is closely associated with clinical outcomes. Furthermore, pre-transplant microbial status has also been associated with the development of acute graft-versus-host disease (GVHD). These results indicate that pre-transplant microbial ecosystem may influence the immune system after allo-SCT, induce alloimmune response such as GVHD, and may finally affect the transplant outcome. Thus, we evaluate the association between pre-transplant microbial diversity and transplant outcomes. Patients and Methods Between April 2013 and March 2015, fecal samples were obtained from 107 patients in Komagome hospital. Fecal samples were collected within 2 weeks before conditioning. Microbial analysis was performed using 16S rRNA gene (hypervariable V1-2 region) sequencing. Operational taxonomic units (OTU)-based microbial diversity was estimated by calculating the Shannon index. Patients were classified into 3 groups based on the diversity index: low (3) diversity group, and we evaluated transplant outcomes such as survival, non-relapse mortality, and the cumulative incidence of GVHD, in these 3 groups. Results Among the 107 patients, there were 18 (16.8%) patients in the low diversity group, 48 (44.9%) in the intermediate diversity group, and 41 (38.3%) in the high diversity group. The median age of all patients was 49 (range: 16-72) years. The median follow-up period for survivors was 597 days (range, 23-1,046 days). We found no significant differences among 3 groups in terms of age, gender, underlying disease, disease status, performance status, hematopoietic cell transplantation comorbidity index, GVHD prophylaxis, conditioning regimen, stem cell sources, and human leukocyte antigen disparity. However, the patients in the low diversity group received intravenous antibiotics just before the conditioning more frequently compared to the patients in the intermediate /high diversity groups. The patients in the low diversity group showed poor survival (p=0.37, Figure 1a), higher non-relapse mortality (p=0.25, Figure 1b) and higher incidence of grade II-VI gastrointestinal GVHD (p=0.77, Fgiure 1c) compared with the patients in the intermediate /high diversity group although these results were not statistically significant. The cumulative incidence of relapse was similar between 3 groups. When compared between patients with and without acute GVHD, the composition of microbiota did not differ significantly between these patients. Discussion and conclusion Our results indicate that pre-transplant microbial diversity did not affect transplant outcomes. Furthermore, in contrast to previous report, the microbial composition was also irrelevant to the development of GVHD. Bacterial translocation after allo-SCT is a key trigger for the development of acute GVHD. Thus, microbial status in this period would be more important than that before allo-SCT. However, the patients in the low diversity group tended to show poor survival, higher incidence of non-relapse mortality and GVHD. Thus, further evaluation with larger sample size might be necessary to confirm the association between pre-transplant microbial ecosystem and transplant outcomes. Disclosures No relevant conflicts of interest to declare.

Description: [Background] Philadelphia chromosome positive (Ph+) leukemia is characterized by highly proliferative nature and clone instability that evokes the emergence of mutated clones, including BCR-ABL1 T315I mutated clone. Established evidence on the use of tyrosine kinase inhibitors (TKIs) after allogeneic hematopoietic stem cell transplantation (HSCT) is still lacking. The use of second-generation TKIs as a maintenance treatment after HSCT has been studied, and it is expected that their use would improve the prognosis by suppressing recurrence. The advent of ponatinib (PON), a potent inhibitor of tyrosine kinase including T315I mutated BCR-ABL1, is expected to improve clinical outcome of Ph+leukemia. However, there are few reports of a maintenance treatment using PON after HSCT. [Methods] We retrospectively reviewed data of 13 patients (pts) who received PON for Ph+leukemia after HSCT while in hematological complete remission (CR) between April 1, 2016 and July 15, 2019. Prophylactic treatment (Pro) was defined as post-transplant administration of PON while in minimal residual disease (MRD) negative CR. Pre-emptive treatment (Pre) was defined as starting PON when the bcr-abl transcript was detected by either quantitative or nested qualitative PCR after HSCT. ABL1 mutation was analyzed through the direct sequencing method. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events version 5.0. Overall survival (OS) was estimated using Kaplan-Meier method. Non-relapse mortality (NRM) and cumulative incidence of hematological relapse (CIR) were calculated using Gray's test. This study protocol was approved by the ethics committee of Tokyo Metropolitan Komagome Hospital. [Results] Underlying diseases were Ph+ALL in 8 pts (5 in CR, 3 in non-CR at HSCT), CML in 5 (all in second chronic phase). ABL1 mutations were analyzed in 12 pts and T315I mutation was detected in 4 pts with Ph+ALL and 2 with CML. Furthermore, compound mutations (CMs) in BCR-ABL1 were detected in 4 pts before HSCT. PON was used in 6 only after HSCT, and in 7 both before and after HSCT. During the median observation after HSCT of 584 days (range, 116-1,110) for survivors, no vascular occlusion event occurred. With regard to adverse events (AEs), grade 3 AEs occurred in 2 pts (15.4%) and no grade 4 AE was observed. Two had liver dysfunction and one of them discontinued PON due to grade 3 abnormalities in liver function tests. One suffered from grade 3 thrombocytopenia. Four had skin rashes lower than grade 3 that were indistinguishable from skin graft-versus-host disease, and all of them resolved through topical steroid therapy. Of all, 6 were in Pro group and 7 were in Pre group. The initial dose of PON was median 15mg (range 45mg/twice a week - 15mg/day) in Pro and median 30mg (range, 15-45mg) in Pre. The median days from HSCT to the start of PON was 107 days (range, 32-174) in Pro and 208 days (range, 50-364) in Pre. The median duration of PON treatment was 297 days (range, 20-699) in Pro and 188 days (range, 5-608) in Pre. At final observation in Pro group, 2 pts relapsed and died during the salvage therapy, 1 pt discontinued PON due to hepatic adverse event, and 3 pts were still on PON. Meanwhile, in Pre group, 5 pts achieved MRD negative CR after PON administration (1 pt also received donor lymphocyte infusion and stop PON due to liver dysfunction, 1 discontinued PON by the patient's request, and 3 of them were still on PON). One pt with CM relapsed but achieved CR through salvage therapy and 1 pt with low performance status (KPS 60) died at home of unknown cause six days after taking PON 30mg daily. For all the 13 pts receiving PON maintenance therapy, OS was 74.6% (95%CI; 39.8-91.1), CIR was 23.1% (95%CI; 5.1-48.5), and NRM was 7.7% (95%CI; 0.4-30.6) at 1 year after transplant (Figure 1). Two out of 4 pts with CMs (V299L/F317L and E255K/T315I/F317L) remains in MRD negative CR. The other 2 with CMs (E255K/T315I and D276G/T315I) had progressed to hematological relapse, suggesting the resistance to PON. In contrast, only one out of 9 without CMs relapsed on PON treatment. [Conclusion] Our results suggested that post-transplant maintenance treatment using PON was tolerable in the majority of patients with Ph+leukemia, although the optimal dose or the initiation strategy (Pre or Pro) are still undetermined. Furthermore, some patients with T315I-inclusive CMs seemed to be resistant to PON. The longer observation in a larger cohort is warranted. Disclosures No relevant conflicts of interest to declare.