ALBERT

Description: Abstract 2007 Background: High-dose cyclophosphamide (HD-CY) + granulocyte-colony stimulating factor (G-CSF) and G-CSF alone have been used to mobilize hematopoietic stem cells (HSCs) for autologous SC transplantation (ASCT) in multiple myeloma (MM). However, which regimen is better is unknown; anti-myeloma effects of HD-CY + G-CSF have not been established. From January 1999 to June 2009, we administered HD-CY+G-CSF but changed to G-CSF alone during July 2009–December 2010. We retrospectively assessed HSC collection efficacy, complications, and anti-myeloma effects of these regimens. Patients and methods: We analyzed 147 MM patients from whom HSCs were to be collected at our institute. For mobilization, 115 patients were administered HD-CY (4 g/m2)+G-CSF (600 mg/body filgrastim or 500 mg/body lenograstim) and 32 were administered G-CSF alone (same dose as HD-CY). Here, 17 patients received therapeutic intervention between mobilization and transplantation without disease progression (PD). To avoid the patient outcome effect, we defined event- and progression-free survivals (EFS and PFS). EFS was defined as PD, death, or therapeutic intervention without PD. PFS was defined as PD or death, where therapeutic intervention without PD was used as a censor. Both were calculated from the start of mobilization. For analyzing response by mobilization, patients receiving therapeutic intervention without PD were excluded. Response was evaluated in those not receiving therapeutic intervention without PD or in whom response could not be evaluated before ASCT. Thalidomide was administered as maintenance therapy to 14 and 6 patients in the HD-CY+G-CSF and G-CSF groups after ASCT. Thalidomide administration was used as a censor. Results: Vincristine, doxorubicin, and dexamethasone (VAD) and HD dexamethasone (HDD) therapies were administered as induction therapy (VAD for 117, HDD for 2, and both for 11). New (bortezomib or thalidomide) and alkylating agents were administered to 7 and 13 patients, respectively. Before mobilization, 26 patients received radiotherapy; none were administered lenalidomide. No statistical difference was seen in baseline characteristics (Durie-Salmon stage, International staging system, interval from diagnosis to mobilization, disease control, and previous therapies) between both groups. However, patients mobilized by G-CSF alone were significantly older. Among 147 patients, 121 underwent planned ASCT. Of the 17 receiving therapeutic intervention without PD, 13 and 4 belonged to the HD-CY+G-CSF and G-CSF groups, respectively. More than 2 × 106 CD34-positive cells/kg were collected from 93% and 75% patients in the HD-CY+G-CSF and G-CSF (p = 0.0079) groups, respectively. More than 4 × 106 CD34-positive cells/kg were collected from 84% and 69% in the HD-CY+G-CSF and G-CSF (p = 0.07). Mean HSC count was 11.4 × 106/kg in the HD-CY+G-CSF group and 4.5 × 106/kg in the G-CSF group (p = 0.0007). Among patients receiving HD-CY+G-CSF, 66% were treated with intravenous antibiotics; 3 suffered cardiac shock and 2 septic shock. However, among those receiving G-CSF alone, no severe complications were seen. Median hospitalization days were 21 and 8 for the HD-CY+G-CSF and G-CSF groups, respectively (p 〈 0.0001). In the HD-CY+G-CSF group, 16% improved in disease control before ASCT, 71% showed no change, and 13% progressed. However, no patient improved, 63% showed no change, and 27% progressed in the G-CSF group (p = 0.015). Median EFS was 25 months in the HD-CY+G-CSF group and 13 in the G-CSF group (fig 1, p value of log-rank test = 0.012). Median PFS was 28 months in the HD-CY+G-CSF group and 15 in the G-CSF group (fig 2, p value of log-rank test = 0.011). Median overall survival did not differ significantly. Conclusion: Regarding the safety and duration of hospitalization, G-CSF alone may be safer and beneficial. However, HD-CY+G-CSF was more effective as a mobilization regimen and showed higher anti-myeloma effects than G-CSF alone. Disclosures: No relevant conflicts of interest to declare.

Description: Previous studies have revealed various extrinsic stimuli and factors involved in the regulation of hematopoiesis. Among these, Notch-mediated signaling has been suggested to be critically involved in this process. Herein, we show that conditional inactivation of ADAM10, a membrane-bound protease with a crucial role in Notch signaling (S2 cleavage), results in myeloproliferative disorder (MPD) highlighted by severe splenomegaly and increased populations of myeloid cells and hematopoietic stem cells. Reciprocal transfer of bone marrow cells between wild-type and ADAM10 mutant mice revealed that ADAM10 activity in both hematopoietic and nonhematopoietic cells is involved in the development of MPD. Notably, we found that MPD caused by lack of ADAM10 in nonhematopoietic cells was mediated by G-CSF, whereas MPD caused by ADAM10-deficient hematopoietic cells was not. Taken together, the present findings reveal previously undescribed nonredundant roles of cell-autonomous and non–cell-autonomous ADAM10 activity in the maintenance of hematopoiesis.

Description: Adult T-cell leukemia-lymphoma (ATL) is an aggressive disease, incurable by standard chemotherapy. NK314, a new anticancer agent possessing inhibitory activity specific for topoisomerase IIα (Top2α), inhibited the growth of various ATL cell lines (50% inhibitory concentration: 23-70nM) with more potent activity than that of etoposide. In addition to the induction of DNA double-strand breaks by inhibition of Top2α, NK314 induced degradation of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), resulting in impaired DNA double-strand break repair. The contribution of DNA-PK to inhibition of cell growth was affirmed by the following results: NK314 inhibited cell growth of M059J (a DNA-PKcs–deficient cell line) and M059K (a cell line with DNA-PKcs present) with the same potency, whereas etoposide exhibited weak inhibition of cell growth with M059K cells. A DNA-PK specific inhibitor, NU7026, enhanced inhibitory activity of etoposide on M059K as well as on ATL cells. These results suggest that NK314 is a dual inhibitor of Top2α and DNA-PK. Because ATL cells express a high amount of DNA-PKcs, NK314 as a dual molecular targeting anticancer agent is a potential therapeutic tool for treatment of ATL.

Description: Abstract 1278 Hematopoietic stem cells (HSCs) have been highly enriched using combinations of more than 10 surface markers. However the simple method using a few positive markers is preferable to identify HSCs location in tissue section. We performed a stringent comparative gene expression profiling analysis to find genes preferentially expressed in the HSC population, and identified a total of 63 genes that are highly expressed in HSC among various hematopoietic cell population. In order to find HSC-specific marker we focused on genes encoding cell surface protein, and found that plexin domain containing 2 (Plxdc2) is highly expressed in CD34—c-Kit+Sca-1+Lineage−(CD34−KSL) HSC population using Plxdc2::GFP knock-in mice. Only 0.2% of whole bone marrow cells were Plxdc2+, and competitive repopulation assay clearly showed that all HSCs are included in the Plxdc2+ fraction. These results identify Plxdc2 as a new marker of HSCs. Plxdc2+ population contain not only HSCs but uncharacterized c-Kitlow/−Sca-1+Lineage−cells. To further purify HSCs, we investigated the additional positive marker. Throughout the screening of various known HSC-related marker, CD150 was selected. CD150 is already recognized as a positive HSC marker (Kiel, et al. Cell 2005). The Plxdc2+CD150+ fraction represented only 0.1%±0.002% in whole bone marrow, and 6% in c-Kit+Sca-1+Lineage− cells, respectively. To test whether the combination of Plxdc2 and CD150 with or without other markers can highly enrich long-term HSCs, we competitively reconstituted irradiated mice with single Plxdc2+CD150+ cells or single Plxdc2+CD150+c-Kit+Sca-1+Lineage− cells. One out of every 4.6 Plxdc2+CD150+ cells (22%), and one out of 2.2 Plxdc2+CD150+c-Kit+Sca-1+Lineage− cells (44%) engrafted and gave long-term multi-lineage reconstitution. The simple combination of Plxdc2 and CD150 significantly increased HSC purity. In addition, we found robust levels of PLXDC2 transcripts in purified human cord blood CD34+ HSCs. Next, we attempted to characterize the another Plxdc2+ fraction which is c-Kitlow/−Sca-1+Lineage−. Multicolor flowcytometric analysis revealed that Plxdc2+c-Kitlow/−Sca-1+Lineage− cells uniformly express CD45, IL7Rα, Thy-1.2, CD27, T1/ST2 (IL1RL1, a subunit of IL33R) and CD25. These cell surface phenotype indicated that this population is probably of lymphoid lineage. However, culturing Plxdc2+ c-Kit low/−Sca-1+Lineage− cells on OP9-DL1, which supports the development of T-cell progenitors to mature T-cells, did not induce T-cell differentiation. Plxdc2+c-Kitlow/−Sca-1+Lineage−cells also did not differentiate into B cells when co-cultured with OP9 stroma cell line. Furthermore Plxdc2+c-Kitlow/−Sca-1+Lineage− cells produce IL-5 and IL-13 in response to IL-33 or a combination of IL-2 and IL-25. These characteristics resemble that of “natural helper (NH) cells”, a recently identified cell population capable of producing large amounts of Th2 cytokines in fat-associated lymphoid clusters (Moro, et al. Nature 2010). Immunohistochemical staining of bone section to detect HSCs, and functional analyses to clarify why Plxdc2 specifically express in HSCs and bone marrow “NH cells” using Plxdc2-deficient mice are our ongoing tasks. Disclosures: No relevant conflicts of interest to declare.

Description: We conducted a prospective randomized study to assess the optimal postremission therapy for adult acute myeloid leukemia in patients younger than 65 years in the first complete remission. A total of 781 patients in complete remission were randomly assigned to receive consolidation chemotherapy of either 3 courses of high-dose cytarabine (HiDAC, 2 g/m2 twice daily for 5 days) alone or 4 courses of conventional standard-dose multiagent chemotherapy (CT) established in the previous JALSG AML97 study. Five-year disease-free survival was 43% for the HiDAC group and 39% for the multiagent CT group (P = .724), and 5-year overall survival was 58% and 56%, respectively (P = .954). Among the favorable cytogenetic risk group (n = 218), 5-year disease-free survival was 57% for HiDAC and 39% for multiagent CT (P = .050), and 5-year overall survival was 75% and 66%, respectively (P = .174). In the HiDAC group, the nadir of leukocyte counts was lower, and the duration of leukocyte less than 1.0 × 109/L longer, and the frequency of documented infections higher. The present study demonstrated that the multiagent CT regimen is as effective as our HiDAC regimen for consolidation. Our HiDAC regimen resulted in a beneficial effect on disease-free survival only in the favorable cytogenetic leukemia group. This trial was registered at www.umin.ac.jp/ctr/ as #C000000157.

Description: We conducted a multi-institutional randomized study to determine whether high-dose daunorubicin would be as effective as standard-dose idarubicin in remission-induction therapy for newly diagnosed adult patients younger than 65 years of age with acute myeloid leukemia. Of 1064 patients registered, 1057 were evaluable. They were randomly assigned to receive either daunorubicin (50 mg/m2 daily for 5 days) or idarubicin (12 mg/m2 daily for 3 days) in combination with 100 mg/m2 of cytarabine by continuous infusion daily for 7 days as induction therapy. Complete remission was achieved in 407 (77.5%) of 525 patients in the daunorubicin group and 416 (78.2%) of 532 in the idarubicin group (P = .79). Patients achieving complete remission received intensive postremission therapy that consisted of either 3 courses of high-dose cytarabine or 4 courses of standard-dose therapy. Overall survival rates at 5 years were 48% for the daunorubicin group and 48% for the idarubicin group (P = .54), and relapse-free survival rates at 5 years were 41% and 41% (P = .97), respectively. Thus, high-dose daunorubicin and standard-dose idarubicin were equally effective for the treatment of adult acute myeloid leukemia, achieving a high rate of complete remission and good long-term efficacy. This study is registered at http://www.umin.ac.jp/ctrj/ as C000000157.

Description: Abstract 1337 Erythroid hypoplasia or aplasia is a hematological condition observed in including idiopathic pure red cell aplasia (PRCA), thymoma-associated PRCA and aplastic anemia. Myelodysplastic syndrome (MDS) with erythroid hypoplasia/aplasia in bone marrow is a rare type of MDS that was not included in existing classifications of MDS. Patients with erythroid hypoplasia/aplasia have common characteristics; transfusion dependencies, immunologic abnormalities and successful immunosuppressive therapies with cyclosporin A (CsA). Thus, we may regard erythroid hypoplasia/aplasia as one of hematological disease entities. However, pathogenic mechanisms of erythroid hypoplasia/aplasia have not been fully elucidated, although T-lymphocyte-mediated inhibition of erythropoiesis is suspected to be the most possible mechanism of the pathogenesis. Recently, we reported that oligoclonal expansion of CD8+/perforin+ T cells was observed in patients with thymoma-associated PRCA and the oligoclonality was exclusively detected in CD8+ T cells, but not CD4+ T cells. To clarify the pathogenetic role of the T-cells, we analyzed the T-cell subsets and therapeutic responses in patients with erythroid hypoplasia/aplasia in bone marrow. Among 253 patients with MDS diagnosed at Hiroshima University Hospital between 2000 and June 2011, 12 patients (4.7%) showed erythroid hypoplasia/aplasia. A total of 22 patients with erythroid hypoplasia/aplasia, including 8 MDS with erythroid hypoplasia/aplasia, 3 idiopathic PRCA, 3 thymoma-associated PRCA and 8 aplastic anemia, were enrolled in this study. All patients were treated with CsA and improvement in anemia in this study followed the International Working Group (IWG) 2006 criteria. For T-cell subset analysis, mononuclear cells (MNCs) were purified from bone marrow (BM) or peripheral blood (PB) of the patients. MNCs were stained with fluorescent (FITC, PE, PerCP or APC)-conjugated antibodies for CD8, perforin, CCR7, CD62L, CD27, CD28 and CD45RO, CD45RA and were subjected to flow cytometric analysis. As controls, 30 patients with MDS without erythroid hypoplasia/aplasia and 30 patients without BM abnormalities were also analyzed. Among 22 patients with erythroid hypoplasia/aplasia, 10 patients (4 MDS with erythroid hypoplasia/aplasia, 1 idiopathic PRCA, 3 thymoma-associated PRCA and 2 aplastic anemia) responded to CsA therapy within 2 to 8 weeks. The median blood hemoglobin concentration increased from 6.5 g/dL at the baseline to 9.3 g/dL with treatment, with a median increase of hemoglobin of 2.8 g/dL from the baseline. We attempted to compare the T-cell subsets between CsA-responders and non-responders. All of 3 thymoma-associated PRCA showed good response to CsA therapy, suggesting that the oligoclonal expansion of a CD8+/perforin+ T-cell subset may be associated with the responses to immunosuppressive therapy. Thus, we focused on a T-cell subpopulation expressing CD8+/perforin+. Intriguingly, the CD8+/perforin+ T cells were significantly increased in the CsA-responders (44.3 ± 9.6%, n=10) compared to the non-responders (19.0 ± 9.3%, n=12, P

Description: Abstract 1403 Resistance to imatinib is most commonly explained by acquired point mutations in the kinase domain of BCR-ABL, which impair drug binding. The more potent ABL1 inhibitors nilotinib and dasatinib have proven largely successful in imatinib-resistant chronic myeloid leukemia (CML) patients with the key exception of the T315I BCR-ABL1 mutant. Ponatinib, also known as AP24534, is an oral, the multi-targeted tyrosine kinase inhibitor (TKI) and highly activity against ABL kinase point mutation included T315I. Ponatinib is currently being investigated in a pivotal phase 2 clinical trial (PACE trial). However, ABL1 inhibitor-resistant patients already harboring mutations have a higher likelihood of developing further mutations under the selective pressure of ABL1 TKIs. The challenge for development of an effective Philadelphia chromosome (Ph) positive leukemia therapy is therefore to develop an alternative treatment strategy that does not rely solely on kinase domain inhibition but rather results in degradation of the offending BCR-ABL1 protein regardless of its mutation status. Histone acetyltransferases (HAT) and histone deacetylases (HDAC) control the acetylation of histones and intracellular proteins, and regulate the transcription and function of the proteins. Several small molecule HDAC inhibitors such as vorinostat (suberoylanilide hydroxamic acid: SAHA) are also evaluated for significant clinical activity in hematological malignancies. Therefore, combination therapy using a ponatinib and an HDAC inhibitor, vorinostat may help prevent development of ABLTKI resistance and may improve their long-term outcome. In the present study, we analyzed the ponatininb and vorinostat efficacy by using the BCR-ABL positive cell line, K562 and murine Ba/F3 cell line which was transfected with imatinib resistant BCR-ABL random mutagenesis and T315I mutant cells. 72 hours treatment of ponatinib exhibits cell growth inhibition and induced apoptosis against K562 cells in a dose dependent manner. We also found that ponatinib potently induced cell growth inhibition of Ba/F3 cells ectopically expressing T315I mutation. We found that phosphorylation of BCR-ABL, Crk-L was decreased and poly (ADP-ribose) polymerase (PARP) was activated in a dose dependent manner in these cells. Combined treatment of Ba/F3 T315I mutant cells with vorinostat and ponatinib caused significantly more cytotoxicity than each drug alone. We investigated the intracellular signaling of ponatinib and vorinostat. Although phosphorylation of BCR-ABL, Crk-L was not reduced after vorinostat treatment for 24 hours, acetylation of histone H4 was increased. Caspase 3 and PARP activation were increased after combination of ponatinib and vorinostat. Moreover, an increase in phosphorylation levels of γ-H2A.X was observed after treatment with ponatinib and vorinostat, compared to ponatinib or vorinostat alone suggests that combination of ponatinib and vorinostat induced DNA damage against T315I mutant cells. We next established ponatinib resistant cells by using Ba/F3 BCR-ABL with resistant random mutants. In the ponatinib resistant cell lines, IC50 of ponatinib was 200nM. BCR-ABL triple point mutations (T315I, E255K and Y253H) were detected by direct sequence and invader analysis. Ponatinib resistant Ba/F3 cells were also resistant to imatinib (IC50: more than 10μM) or nilotinib (IC50: 7.5μM) and also resistant to dasatinib (IC50: more than 100nM). We investigated the efficacy between ponatinib and vorinostat by using these cell lines. Combined treatment of Ba/F3 ponatinib resistant cells with ponatinib and vorinostat caused significantly more cytotoxicity. Moreover, acetylation of histone H4, caspase 3 and PARP activation were found after combination of ponatinib and vorinostat. Data from this study suggested that administration of the ponatinib and HDAC inhibitor, vorinostat may be a powerful strategy against BCR-ABL mutant cells and enhance cytotoxic effects of ponatinib in those BCR-ABL mutant cells. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4563 Introduction: Cord blood transplantation with fludarabine-containing toxicity-reduced conditioning (RT-CBT) has been widely applied to adult patients who have advanced hematologic diseases and are not eligible for conventional conditioning. Severe immune-mediated reactions early after transplant (preengraftment immune reactions, PIR) have been the major cause of early non-relapse mortality particularly for elderly patients. Mycophenolate mofetil (MMF) has been administered since late December 2005 at our institute and was shown to be effective in reducing early toxicity (Transplantation 92:366,2011). However, disease relapse has been the issue hampers successful outcomes, and the optimal GVHD prophylaxis has still not been established. We conducted a retrospective analysis of those who received RT-CBT at our institute using tacrolimus + MMF focusing on the impact of MMF dosing on the outcome. Design and Methods: We retrospectively reviewed patients aged 55 and older who underwent single-unit RT-CBT and GVHD prophylaxis using tacrolimus + MMF consecutively. Median dose of MMF was 33 mg/kg recipient body weight per day, ranging from 13 to 80 mg/kg, divided by 2 or 3 times at each physician’s determination. MMF was started on day -1 and continued until neutrophil recovery (〉500/μl). Patients who had prior history of transplantation, were in poor performance status (ECOG PS 4 and greater), had active bacterial or fungal infections at the time of conditioning, had diagnosed as multiple myeloma were excluded. Results: From December 2005 to April 2011, 134 patients underwent RT-CBT at our institute. Twenty-seven were excluded due to active infection at the day of transplant or poor performance status, and 107 patients were subjected to the following analysis. The diagnoses included were AML/MDS (n=87), ALL (n=2) CML/MPD (n=4), ML (n=11), and SAA (n=3). Eighty-six (80%) had high risk diseases, and 29 (27%) and 6 (6%) were in ECOG PS 2 and 3, respectively. Cumulative incidence of neutrophil recovery 〉500/μl were 81 %. Median follow-up time of survivors was 521 days (range, 83 – 1847). Cumulative incidences of non-relapse mortality were 21.4 % and 27.3 % at day 100 and 1 year post-transplant, respectively. Overall survival and event-free survival at 1 year post-transplant were estimated as 47.7 % and 31.7 %, respectively. The patients were subdivided into 2 groups according to MMF dosing (≥30 vs.

Description: Abstract 4541 Background: The heterogeneous status of host immune defenses may influence the risk of infection and graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation (HSCT). In such defense, dendritic cells (DC) which act as specialized antigen-presenting cells that bridge the innate and adaptive immune systems, and NK-cells, responsible for the innate defense against infections and residual tumor cells, are essential cell components. Objectives: To monitor the recovery of different subsets of DC and NK cells after unrelated umbilical cord blood (UCB), bone marrow (BM), and peripheral blood (PBSC) HSCT and to evaluate the impact of the distribution of these cell subsets on the outcome of the transplant. Methods: Overall, 34 patients (median age 13y; range 1–63y) receiving a UCB (n=15), BM (n=14) or PBSC (n=5) unrelated HSCT were studied. The most common diagnosis was acute leukemia (ALL, 12 cases; AML, 10; CML, 5; aplastic anemia, 4; MDS, 2; Hodgkin lymphoma, 1; SCID, 1), a majority of patients were males (56%), and received myeloablative conditioning (MAC) regimens (73%). Antithymocyte globulin (ATG) was used in 38% and total body irraditation (TBI) in 41% of cases. Median time to neutrophil engraftment was 18 days (range: 12–45). T-cell (CD4+, CD8+, CD4−8−, CD4+8+), DC [CD123+ plasmacytoid(p)DC, CD11c+ myeloid(m)DC, and CD16+ monocytoid(mo)DC] and NK cell subsets (CD3−/CD19− 56++16− and 56+16++) were quantified by multiparametric flow cytometry at 7 sequential time points (pre-transplant, at engraftment, and at days 3, 7, 14, 21 and 60 after engraftment). Results: As compared to BM/PBSC, UCB was associated with a delayed neutrophil recovery (28 days vs. 17 days; p=0.01), and a trend to lower counts of all T-, NK- and pDC subsets, particularly for the CD4+ and CD4−/CD8− T-cells during the first 3 weeks after recovery. Conversely, no significant differences were observed between both groups as regards the distribution of mDC and moDC. The use of TBI, MAC or ATG were not associated with the reconstitution of the studied cell subsets. In contrast, patients who died from transplantation-related causes (TRM) had significantly lower counts of pDC and mDC during the first 3 weeks after HSCT. At day 21 after engraftment, the median number of pDC and mDC was 0.9 and 2.0/uL among patients who died from TRM vs. 7.1 (p=.006) and 8.4/uL (p=.01) in the remainder, respectively). Patients presenting grade II-IV acute GVHD also had significantly lower pDC counts at days 14 and 21. There was no significant association of both the hematopoietic stem cell source and the conditioning regimen on the risk of TRM or acute GVHD. Conclusion: Low pDC counts in the first weeks after unrelated HSCT are associated with an increased incidence of GVHD and mortality. The precise mechanisms that might explain the role of pDC on immunity early after HSCT deserve further investigations. Disclosures: No relevant conflicts of interest to declare.