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The introduction of tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) treatment has dramatically improved the prognosis of CML patients and reduced the number of patients receiving allogeneic stem cell transplantation (allo-SCT). However, the impact of the newest-generation TKIs on the overall survival (OS) after allo-SCT has not been well described. To investigate the beneficial effects of TKIs on the prognosis after allo-SCT, we conducted a retrospective observational study using the Transplant Registry Unified Management Program database in Japan. We analyzed 1188 patients (male/female: 738/450; median age: 44 years; range: 16-75) who underwent their first allo-SCT between January 2001 and December 2018. We divided the patients into two groups according to the TKI treatment used before allo-SCT: group 1 was treated with the first generation TKI imatinib; group 2 was treated with the second generation TKIs nilotinib, dasatinib, or bosutinib and/or the third generation TKI ponatinib. We compared the post allo-SCT OS between the two groups. The 3-year OS rates (95%CI) of groups 1 and 2 were 59.3% (54.8%-63.5%) and 65.8% (61.6%-69.6%), respectively (p = 0.017). Multivariate analysis confirmed that group 2 had superior OS after allo-SCT compared to group 1 (p = 0.002). Other factors associated with superior prognosis were age ≤65, performance status (PS) 0/1, a 6/6 HLA-matched donor and chronic-phase (CP) disease status at allo-SCT. A subgroup analysis showed poor prognoses for patients who could not obtain a molecular response before allo-SCT and patients with positive T315I mutation in the BCR/ABL gene. In group 2, early allo-SCT was correlated with superior OS in patients with a blast-crisis disease status at allo-SCT (p = 0.001). The cumulative incidence of non-relapse mortality rate significantly decreased in group 2 (p = 0.0005). The post allo-SCT OS was improved both by pre- and post-management of allo-SCT and by the introduction of newer TKIs.

Thus far, there have been no large cohort studies on total body irradiation (TBI)-containing conditioning regimens without antithymocyte globulin (ATG) in adults with aplastic anemia (AA) undergoing umbilical cord blood (UCB) transplantation (UCBT). We retrospectively analyzed 115 adults with idiopathic AA undergoing UCBT using TBI-containing reduced-intensity conditioning (RIC) regimens without ATG between 2000 and 2018 on behalf of the Adult Aplastic Anemia Working Group of the Japanese Society for Hematopoietic Cell Transplantation. We then compared transplantation outcomes between a fludarabine (Flu)- and melphalan (Mel)-based regimen (FM) and a Flu- and cyclophosphamide (Cy)-based regimen (FC). The median patient age at UCBT was 41 years. The median total nucleated cell and total CD34+ cell doses in a UCB unit at cryopreservation were 2.5 × 107/kg and 0.7 × 105/kg, respectively. The median follow-up period for survivors was 47 months. The cumulative incidence rate of neutrophil engraftment was 76.5%, and the 4-year overall survival (OS) rate was 64.3%. In multivariate analysis, the covariates that were significantly associated with a higher neutrophil engraftment were total CD34+ cell dose in an UCB unit (≥ 0.7 × 105/kg; hazard ratio, 0.57, P = 0.01) and total dose of TBI (4 Gy of TBI; hazard ratio, 0.32, P = 0.01). There was no significant difference in the cumulative incidence of neutrophil engraftment and the 4-year OS between the FM and FC groups. In conclusion, TBI-containing RIC regimens without ATG are suitable for adults with AA undergoing UCBT. There were no significant differences in transplantation outcomes between the FM and FC groups.

Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Stem cell source or HLA disparity may exert a significant impact on the overall survival (OS) after the development of aGVHD. In order to clarify this point, we performed a retrospective analysis using a database of the Japan Society for HCT. We analyzed the clinical outcomes of 10,035 patients who developed grade II-IV aGVHD. The median age of the patients was 48 years. The probability of 2-year OS after the onset of grade II-IV aGVHD in the study cohort was 54.1%. The multivariate analysis showed that the HLA ≥2-loci mismatched related donor and HLA 1-locus mismatched unrelated donor were significantly associated with an inferior OS after grade II-IV aGVHD. In a subgroup analysis, peripheral blood stem cells and HLA disparity were associated with an inferior OS in patients who received related or unrelated HCT. Thus, the clinical outcome after grade II-IV aGVHD significantly varied as per the combination of the presence of HLA disparity and stem cell source. Further research using other databases is necessary to confirm our findings.

Chromosomal abnormalities in the role of prognostic factor for transplant patients with myelofibrosis (MF) are not fully investigated. Regarding complex karyotype (CK), we retrospectively analyzed 241 patients with primary and secondary MF who received a first allogeneic hematopoietic cell transplantation (HCT). Based on an unfavorable karyotype in the Dynamic International Prognostic Scoring System, we compared the outcomes in 3 groups: favorable karyotype, unfavorable karyotype including CK (unfavorable-CK(+)), and unfavorable karyotype not including CK (unfavorable-CK(-)). Overall survival was significantly shorter in the unfavorable-CK(+) group (hazard ratio (HR) 2.49, 95% CI: 1.46-4.24, P 0.001), whereas there was no difference between the unfavorable-CK(-) group and the favorable group (HR 0.57, 95% CI: 0.20-1.59, P = 0.28). In addition, a significantly higher proportion of patients in the unfavorable-CK(+) group did not achieve complete remission after HCT (P = 0.007). The cumulative incidence of disease progression was significantly higher in the unfavorable-CK(+) group (HR 2.5, 95% CI 1.6-3.92, P 0.001), whereas that in the unfavorable-CK(-) group was comparable to that in the favorable group (HR 0.49, 95% CI 0.12-1.94, P = 0.31). Further investigations will be needed to clarify the impact of CK on transplant outcomes in MF.

Temcell is a cryopreserved, human bone marrow-derived mesenchymal stem cell (MSC) product approved for the treatment of patients of all ages with acute graft-versus-host disease (GVHD). Initial experience with Temcell in a real-world setting from a cellular therapy registry in Japan is presented. A total of 381 consecutive patients were enrolled since its approval in 2016. The median cell number infused was 2.00 × 106/kg. The most common number of infusions was 8 in 100 patients. Of the 306 evaluable patients, the overall response rate (ORR) on day 28 after the start of MSC therapy was 56%. Of the 151 evaluable patients who received it as second-line therapy following first-line steroid therapy for classic acute GVHD, the ORR was 61%. Liver involvement of GVHD and ≥14 days from first-line steroid therapy to second-line MSC therapy was associated with a lower ORR. Day 28 ORR, patient age, GVHD grade, GVHD organ involvement, and a number of GVHD therapies before MSC therapy were associated with nonrelapse mortality. Overall survival at 6 months in 381 patients was 40%. This study suggests that Temcell is one of the treatment options for steroid-refractory acute GVHD until a new treatment with survival benefit is developed.

To overcome the delayed or failed engraftment after unrelated cord blood transplantation (CBT), we conducted a multicenter phase II study of intrabone single-unit CBT without antithymocyte globulin (ATG) for adult patients with hematological malignancies (UMIN-CTR, UMIN000020997). Sixty-four patients received an intrabone injection of unwashed (n = 61) or washed (n = 3) cord blood after local anesthesia. All injection-related adverse events were mild and resolved spontaneously. Sixty-two patients were evaluable for the efficacy of intrabone CBT of serological HLA-A, -B, and -DR ≥ 4/6 matched cord blood with a median number of 2.57 × 10^7/kg cryopreserved total nucleated cells. The probability of survival with neutrophil engraftment on day 28 was 77.4% (95% confidence interval, 67.0–85.8%), which exceeded the threshold value. The cumulative incidences of neutrophils ≥ 0.5 × 10^9/L on day 60 was 80.6% (68.2–88.6%), with a median time to recovery of 21 days after transplantation. The cumulative incidences of platelets ≥ 20 × 10^9/L and platelets ≥ 50 × 10^9/L on day 100 were 75.8% (62.6–84.9%) and 72.6% (59.4–82.1%), respectively, with median time to platelets ≥ 20 × 10^9/L and platelets ≥ 50 × 10^9/L of 38 and 45 days after transplantation, respectively. The cumulative incidences of grade II–IV and III–IV acute graft-versus-host disease were 29.0% and 6.5%, respectively. All responded to steroid therapy, and secondary treatments were not required. The present study suggests the efficacy of intrabone single-unit CBT without ATG in terms of early engraftment and controllable acute graft-versus-host disease.

To date, there are no data focusing on outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelodysplastic/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U). This study aimed to evaluate outcomes and prognostic factors in patients with MDS/MPN-U after allo-HSCT using Japanese nationwide registry data. The primary endpoint was 3-year overall survival (OS); secondary endpoints included the cumulative incidence of relapse and nonrelapse mortality (NRM). We evaluated the prognostic factors for 3-year OS by univariate analysis using the log-rank test. In our cohort of 86 patients with MDS/MPN-U, we found a 3-year OS of 48.5%, cumulative incidence of relapse of 23.7%, and NRM of 26.3%. The 3-year OS was significantly worse in patients age ≥50 years compared with those age50 years (38.1% versus 65.0%; P = .049) and in patients with disease progression compared with those without disease progression (28.4% versus 57.2%; P = .042). Our results suggest that allo-HSCT may offer a curative option for patients with MDS/MPN-U, and that age and disease status could be important indicators in helping clinicians determine treatment options for these patients.

A prospectively registered observational study was conducted to assess the significance of allogeneic hematopoietic stem cell transplantation from highly HLA-matched unrelated donors (UD) and cord blood (CB) on outcomes in adult acute leukemia (AL) and myelodysplastic syndrome (MDS). Between 2007 and 2015, 231 transplant-eligible patients were registered for a phase 2 study of alternative donor transplantation. After registration, a sufficient time period was given to find appropriate UD. Patients received CB transplantation (CBT) if an appropriate UD was unavailable. In total, 119 patients received CBT (106 AL and 13 MDS) and 91 patients received UD transplantation (UDT) (86 AL and 5 MDS). The median age was 39 years in both groups. The primary objective was overall survival (OS); secondary objectives included cumulative incidences of non-relapse mortality (NRM) and relapse, and disease-free survival. Diagnosis, disease status at transplantation, refined disease risk index, and hematopoietic cell transplant-specific comorbidity index did not differ between UDT and CBT. In multivariate analyses, graft source was not a significant risk factor for all objectives. In adjusted analyses, UDT and CBT showed similar OS, NRM, and relapse in this prospective study. CB can be a comparable alternative stem cell source to UD by achieving a timely transplant.

Almost comparable transplantation outcomes have been reported with HLA-matched unrelated donor transplantation (UDT) and cord blood transplantation (CBT). We conducted a prospective phase 2 study to assess the efficacy and safety of single-unit myeloablative CBT in adult leukemia and myelodysplastic syndrome. Because the day 180 survival of UDT was approximately 80%, we determined the alternative hypothesis of expected day 180 survival with a successful engraftment rate of 80% and set the null hypothesis of threshold rate at 65%. Sixty-two patients (median age, 37 years) were registered, including 28 with acute myelogenous leukemia, 25 with acute lymphoblastic leukemia, and 9 with myelodysplastic syndrome. Of 61 eligible patients, 52 were successfully engrafted and survived at day 180 (85%; 95% confidence interval, 74% to 93%). Single-unit CBT was judged to be effective because the null hypothesis was rejected (P.001). Furthermore, neutrophil engraftment was observed in 57 patients (92%); the incidences of grade II-IV acute and chronic graft-versus-host disease were 30% and 32%, respectively; and the cumulative incidences of nonrelapse mortality and relapse at 2 years were 18% and 13%, respectively. The present study showed favorable survival outcomes with single-unit CBT. Therefore, this method may be considered if a well-HLA-matched UDT cannot be obtained.

Acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1) is an enzyme that converts cholesterol to cholesteryl esters. A recent in vivo study reported that inhibiting ACAT1 enzyme activity upregulates the membrane cholesterol levels of T cells, enhancing their cytotoxic function. In the present study, we investigated whether the presence of the ACAT1 single nucleotide polymorphism rs11545566 in transplant donors affected the risk of graft-versus-host disease (GVHD) in 116 adult patients who underwent bone marrow transplantation from human leukocyte antigen-identical sibling donors, and who received GVHD prophylaxis with short-term methotrexate and cyclosporine. The frequencies of the AA, AG, and GG genotypes in the donors were 31%, 45%, and 24%, respectively. The cumulative incidences of grade II–IV acute GVHD on day 100 in patients whose donors had AA vs. non-AA genotypes were 6% and 18%, respectively, and those of extensive chronic GVHD at 2 years were 7% and 32%, respectively. Multivariate analyses demonstrated that donor rs11545566 non-AA genotypes showed a trend toward a higher incidence of grade II–IV acute GVHD (P = 0.079), and were significantly associated with a higher incidence of extensive chronic GVHD (P = 0.021). These results suggest that donor ACAT1 rs11545566 genotype may be predictive of GVHD., ファイル公開：2021/01/01

Genomic deletion of donor-patient-mismatched HLA alleles in leukemic cells is a major cause of relapse after allogeneic hematopoietic stem cell transplantation (HSCT). Mismatched HLA is frequently lost as an individual allele or a whole region in HLA-class I, however, it is downregulated in HLA-class II. We hypothesized that there might be a difference in T cell recognition capacity against epitopes associated with HLA-class I and HLA-class II and consequently such allogeneic immune pressure induced HLA alterations in leukemic cells. To investigate this, we conducted in vitro experiments with T cell receptor-transduced T (TCR-T) cells. The cytotoxic activity of NY-ESO-1-specific TCR-T cells exhibited similarly against K562 cells with low HLA-A*02:01 expression. However, we demonstrated that the cytokine production against low HLA-DPB1*05:01 expression line decreased gradually from the HLA expression level approximately 2-log lower than normal expressors. Using sort-purified leukemia cells before and after HSCT, we applied the next-generation sequencing, and revealed that there were several marked downregulations of HLA-class II alleles which demonstrated consistently low expression from pre-transplantation. The marked downregulation of HLA-class II may lead to decreased antigen recognition ability of antigen-specific T cells and may be one of immune evasion mechanism associated with HLA-class II downregulation.

Cord blood transplantation (CBT) is a curative therapeutic option for patients with acute myeloid leukemia (AML) who do not have an HLA-matched donor. The decline in early nonrelapse mortality (NRM) after CBT has significantly improved overall survival (OS) during the past 20 years because of advances in CBT practices, including more careful patient selection, use of safer conditioning regimens, better cord blood unit selection, and improved supportive care. A previous study reported a conditioning regimen comprising fludarabine, busulfan, and melphalan (Flu/Bu4/Mel) developed for patients undergoing CBT in non-complete remission (CR) myeloid malignancies that showed durable engraftment and remission with acceptable nonrelapse mortality (NRM), leading to excellent survival outcomes. However, no prior study has focused on the role of Flu/Bu4/Mel in CBT conditioning and compared it with conventional myeloablative conditioning (MAC) for AML patients in CR. We aimed to investigate the efficacy and safety of Flu/Bu4/Mel compared with cyclophosphamide and total body irradiation (CY/TBI)-based MAC for AML patients in CR who underwent CBT. Patients were selected from the Japanese nationwide transplantation registry according to the following inclusion criteria: (1) patients with AML aged ≥16 years, (2) first single-unit CBT, and (3) CR at the time of transplantation. Of 477 eligible patients, 148 (31.0%) received CY/TBI, 223 (46.8%) received high-dose cytarabine (HDCA)/CY/TBI, and 106 (22.2%) received Flu/Bu4/Mel. The probability of OS at 3 years was 64.8% (95% confidence interval [CI], 56.0% to 72.3%) in the CY/TBI group, 65.1% (95% CI, 57.8% to 71.4%) in the HDCA/CY/TBI group, and 65.5% (95% CI, 53.7% to 74.9%) in the Flu/Bu4/Mel group (P = .71); the cumulative incidence of relapse at 3 years was 22.0% (95% CI, 15.2% to 29.5%), 17.2% (95% CI, 12.2% to 22.9%), and 18.0% (95% CI, 11.2% to 26.2%), respectively (P = .40); and the cumulative incidence of NRM at 3 years was 17.2% (95% CI, 11.5% to 24.0%), 20.7% (95% CI, 15.4% to 26.7%), and 18.6% (95% CI, 11.4% to 27.2%), respectively (P = .95). Multivariate analysis identified Flu/Bu4/Mel as a favorable factor for OS; however, it was not significantly favorable for relapse and NRM in the CY/TBI, HDCA/CY/TBI, and Flu/Bu4/Mel groups (hazard ratio [HR], .50 [95% CI, .29-.88], P = .015; .67 [95% CI, .31-1.46], P = .31; and .55 [95% CI, .26-1.18], respectively; P = .12). Flu/Bu4/Mel was a favorable factor for neutrophil engraftment (HR, 1.51; 95% CI, 1.08 to 2.12; P = .016). Multivariate analysis showed that Flu/Bu4/Mel had a favorable prognostic impact on OS and neutrophil engraftment despite the non-TBI regimen. Our findings suggest that Flu/Bu4/Mel may sustain the antileukemia effect with decreasing NRM and could be a favorable CBT conditioning regimen for patients with AML in CR.

Sporadic incidence of veno-occlusive disease (VOD) continues to occur, despite achievement of recommended busulfan (BU) concentrations after real-time BU dose adjustment. To explore the potential influence of glutathione S-transferase (GST) and cytochrome P450 (CYP) genotypes on plasma BU concentration, subsequent VOD, and transplant outcome, we assessed the polymorphisms of multiple GST and CYP genes. Fifty-five patients were included (median age 38 years; range 21-67). Of these, 49 received dose-adjusted BU/CY therapy. Twenty-six patients received transplants from human leukocyte antigen-identical siblings, 26 from unrelated donors. The GSTA1*A/*A genotype was significantly associated with lower BU first-dose area under curve (AUC1st). We found that patients with higher AUC1st showed a significantly higher serum total bilirubin during the first month after transplantation, but this was not necessarily associated with subsequent development of VOD. We further analyzed a possible association of GST and CYP polymorphisms and VOD development, and found none of the polymorphisms investigated was associated with VOD incidence. Regarding transplant outcomes, GSTM1-positive patients showed lower relapse rates and better overall survival in multivariate analyses. These results suggest that a GSTM1-positive genotype in patients receiving BU/CY conditioning protects against relapse of hematological malignancies after allogeneic hematopoietic stem cell transplantation.

Conventional cytogenetic analyses and fluorescent in situ hybridization (FISH) are helpful for stratifying patients with multiple myeloma (MM) into high-risk [t(4;14), t(14;16), and/or del 17p] and standard-risk [t(11;14)] categories. However, the prognosis of patients with MM treated with autologous stem cell transplantation (ASCT) stratified according to these categories remains unclear. This retrospective observational study analyzed 97 patients with MM who received a single, planned ASCT after treatment with 200 mg/m2 melphalan between 2001 and 2011. The patients were grouped according to chromosomal abnormality, including t(11;14) (n = 45), t(4;14) (n = 31), del 17p (n = 10), t(11;14) with del 17p (n = 7), and t(4;14) with del 17p (n = 4). Median overall survival (OS) of the t(11;14) group (64.1 months) was not significantly different from that of the t(4;14) group (not reached), but it was significantly longer than that of the del 17p group (23.0 months; P = .002). G-banding revealed that the median OS of the t(11;14) group with additional chromosomal abnormalities (ACAs) (46.2 months) was significantly shorter than that of the t(11;14) group without ACAs (not reached; P = .005) and the t(4;14) group (not reached; P = .010). These findings highlight the importance of G-banding in patients with t(11;14) MM.

Owing to the difficulty in isolating T cells from human biopsy samples, the characteristics of T cells that are infiltratinghuman acute graft-versus-host disease (GVHD) tissues remain largely uninvestigated. In the present study, TCR-β deep sequencing of various GVHD tissue samples and concurrent peripheral blood obtained from transplant recipients was performed in combination with functional assays of tissue-infiltrating T cell clones. The T cell repertoire was more skewed in GVHD tissues than in the peripheral blood. The frequent clonotypes differed from tissue to tissue in the same patient, and the frequent clonotypes in the same tissue differed from patient to patient. Two T cell clones were successfully isolated from GVHD skin of a patient. In a cytotoxicity assay, both Tcell clones lysed patient peripheral blood mononuclear cells, but not donor-derived Epstein-Barr virus-transformed lymphoblastoid cells. Their clonotypes were identical to the most and second most frequent T cell clonotypes in the original GVHD skin and accounted for almost all of the skin-infiltrating T cells. These results suggest that human acute GVHD may result from only a few different alloreactive cytotoxic T cell clones, which differ from tissue to tissue and from patient to patient. The characterization of T cells infiltrating human GVHD tissues should be further investigated.

Antithymocyte globulin (ATG) is widely used to reduce acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD). To clarify the different impacts of ATG for conditioning across different donor types, we retrospectively analyzed patients with acute leukemia (n = 6617) who underwent hematopoietic stem cell transplantation between 2008 and 2015 with ATG (n = 279) or without ATG (n = 6338). Because thymoglobulin is the only ATG drug approved for GVHD prophylaxis in Japan since September 2008, we included thymoglobulin alone in the present analysis. The survivors’ median follow-up time was 1081 days. Patients were categorized into 5 groups: cord blood (CB; n = 1915), matched related donor (n = 1772), 1-antigen mismatched related donor (1-MMRD; n = 225), matched unrelated donor (MUD; n = 1742), and 1-allele mismatched unrelated donor (1-MMUD; n = 963). In multivariate analysis, ATG decreased overall survival (hazard ratio [HR], 1.403; P = .054) and GVHD-free/relapse-free survival (GRFS) (HR, 1.458; P = .053) in association with increased nonrelapse mortality (NRM) (HR, 1.608; P = .03) with CB, whereas it improved GRFS (HR, 0.515; P < .01) and decreased grades II to IV aGVHD (HR, 0.576; P < .01), extensive cGVHD (HR, 0.460; P = .02), and NRM (HR, 0.545; P = .03) with 1-MMUD. ATG did not impact survival with 1-MMRD and MUD. The use of ATG in conditioning is beneficial due to the reduction in acute/chronic GVHD without increasing NRM or disease relapse only in 1-MMUD transplantation. On the other hand, ATG is not recommended for CB transplantation.

Previous Japanese studies have shown that bone marrow transplantation (BMT) is associated with better survival compared with peripheral blood stem cell transplantation (PBSCT) from a matched related donor (MRD). PBSCT recipients have shown higher incidences of severe graft-versus-host disease (GVHD) and nonrelapse mortality (NRM) compared with BMT recipients. In recent years, the efficacy and safety of antithymocyte globulin (ATG) for PBSCT recipients has been evaluated worldwide. In the present study, we aimed to compare BMT and PBSCT recipients to identify current improvements and unmet needs among MRD PBSCT recipients. In addition, we evaluated the impact of ATG administration on the outcomes of PBSCT recipients. We retrospectively analyzed patients age ≥16 years with acute leukemia, myelodysplastic syndrome, or chronic myelogenous leukemia who underwent their first BMT or PBSCT from an MRD between 2009 and 2018 in Japan. A total of 3599 transplantations were performed (BMT, n = 1218; PBSCT without ATG [PBSCT-ATG(-)], n = 2288; PBSCT with ATG [PBSCT-ATG(+)], n = 93). The PBSCT-ATG(-) group had a higher NRM (hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.08 to 1.57; P = .005) and lower overall survival (OS) (HR, 1.16; 95% CI, 1.04 to 1.30; P = .011) compared with the BMT group. Furthermore, the PBSCT-ATG(-) group had higher incidences of grade III-IV, stage 2-4 gut, high-risk, and steroid-refractory acute GVHD compared with the BMT group. Acute GVHD had a negative impact on NRM and OS. The PBSCT-ATG(-) group also was associated with an elevated risk of chronic GVHD (HR, 1.89; 95% CI, 1.24 to 2.57; P.001) and extensive chronic GVHD (HR, 1.44; 95% CI, 1.23 to 1.68; P.001). The incidences of acute GVHD, chronic GVHD, and NRM and chronic GVHD-free relapse-free survival rates were comparable between the PBSCT-ATG(+) and BMT groups. The OS of patients with acute GVHD was similar in the 3 donor groups. Patients treated with reduced-intensity conditioning in the PBSCT-ATG(+) group had a higher relapse rate and lower OS rate compared with those in the BMT group. In this Japanese cohort, standard calcineurin inhibitor-based GVHD prophylaxis was not sufficient for recipients of MRD PBSCT because of the high incidence of severe acute GVHD. Prophylactic ATG was found to be a promising strategy against GVHD.

Second allogeneic hematopoietic stem cell transplantation is a curative treatment option for patients with hematologic malignancies. However, it is unclear whether HLA discrepancy between graft and first donor has an impact on the outcome of second transplantation. We retrospectively analyzed 646 patients receiving second transplantation after an initial HLA mismatched transplantation. With regard to graft-versus-host, the one-allele mismatch (1 mismatch) group (SHR, 1.88; 95%CI: 0.79-4.45; P=0.163) and more than one-allele mismatch group (≥ 2 mismatch) (SHR, 1.84; 95%CI, 0.75–4.51; P=0.182) had higher risks of grade III–IV acute graft-versus-host disease (GvHD) compared to the HLA-matched (0 mismatch) group. In contrast, no difference in risk of acute GvHD was found among the 0, 1, and ≥ 2 mismatch group with respect to graft-versus-first donor. With regard to graft-versus-host, the ≥ 2 mismatch group showed a significantly higher risk of treatment-related mortality (SHR, 1.90; 95%CI, 1.04–3.50; P=0.038) compared to the 0 mismatch group, while the risk of relapse was slightly lower in the ≥ 2 mismatch group (SHR, 068; 95%CI, 0.44–1.06; P=0.086). In contrast, with regard to graft-versus-first donor, there were no significant differences in treatment-related mortality or relapse among the three groups. These findings suggested that HLA discrepancy between graft and host induces transplant-related immunological responses in second transplantation leading to an increase in treatment-related mortality, in contrast, the biological effects of HLA discrepancy between graft and first donor on outcome may be negligible.

Introduction: Chimeric antigen receptor-modified T cells targeting CD19 (CD19.CAR-T cells) have shown clinical success in patients with hematological malignancies. Despite the encouraging results obtained with this novel therapy, a major concern to its global spread, particularly in developing countries, is its high cost. We developed a method of non-viral gene transfer using piggyBac transposon to reduce the cost of CAR-T therapy. In preclinical study, the median number and transduction efficiency of CAR-T cells obtained from 2x10 7 PBMC in 9 donors were 1.0x10 8 (range, 0.58-1.8x10 8) and 51% (range, 29-73%), respectively. The major subset of CAR-T cells was phenotypically CD8+CD45RA+CCR7+, closely related T-memory stem cells. Ex vivo, CD19.CAR-T cells showed cytotoxic effect on CD19 positive tumor cell lines. In NSG mice model, CD19.CAR-T cells successfully inhibit tumor growth. CAR gene integration sites were determined by inverse polymerase chain reaction and subsequent next-generation sequencing using MiSeq and equally distributed throughout the genome without preference for specific sites. The pre-clinical testing in mouse demonstrated safe toxicity profile at the 50 times dose of CD19.CAR-T cells. We started a human clinical trial to define feasibility, toxicity, maximum tolerated dose and clinical response of CD19.CAR-T cells (jRCTa040190099). Methods: We report the results of cohort 1 of the study in which the safety and efficacy of autologous CD19.CAR-T in patients with relapsed or refractory B-precursor acute lymphoblastic leukemia were evaluated. We engineered autologous T cells via the piggyBac transposon system with CD19.CAR-expression transposon vector and piggyBac transposase-expression vector to express CD19.CAR incorporating CD28 costimulatory domain. We designed this phase I trial using a modified 3 + 3 design to enroll 3-12 patients with relapsed or refractory acute lymphoblastic leukemia in both children and adults. In this study, patients in cohorts 1 (16-60 years old) and 2 (1-15 years old) receive 1 × 10 5 CAR-transduced T cells per kg. Patients in cohorts 3 and 4 (both 1-60 years old) receive 3 × 10 5 and 1 × 10 6 CAR-transduced T cells per kg, respectively. All patients receive 25mg/m 2/d of fludarabine and 250mg/m 2/d of cyclophosphamide for 3 days followed by a single infusion of CAR-T cells. Results: Three patients were enrolled in cohort 1 and infused with 1 × 10 5 CAR-transduced T cells per kg. All patients had previously undergone allogeneic hematopoietic stem cell transplantation. All patients had achieved a hematological complete response with salvage treatment before CAR-T therapy. None of the patients had dose-limiting toxicities (DLT) defined as nonhematological toxicities above grade 4 or cytokine release syndrome (CRS) above grade 4 or graft versus host disease (GVHD) above 4, or grade 3 nonhematological toxicities and GVHD not improved to grade 2 within 4 weeks after CAR-T infusion. There was no occurrence of non-hematological adverse events above grade 3. CRS was observed in one patient (grade 1) who also developed headache due to infiltration of CAR-T cells into the spinal fluid. In two patients, B cell aplasia lasted 2 and 9 months, respectively. Elevation of serum cytokine levels was observed in all patients and the peak time point was 7-21 days after CAR-T cell infusion. Conclusions: CD19.CAR-T cell infusion produced by the piggyBac transposon gene engineering system was safe in cohort 1 of our study. As no patients had DLT in cohort 1, we are enrolling the patients in further cohorts. Disclosures Murata: MSD: Honoraria; Kyowa Kirin: Honoraria; Sumitomo Dainippon Pharma: Honoraria; FUJIFILM: Honoraria; Toyama Chemical: Honoraria; Novartis: Honoraria; JCR Pharmaceutical: Honoraria; Astellas: Honoraria; Miyarisan Pharmaceutical: Honoraria; Asahi Kasei: Honoraria; GlaxoSmithKline: Honoraria; Celgene: Honoraria; Otsuka Pharmaceutical: Honoraria.

Wilms' tumor 1 (WT1) is constantly expressed in leukemic cells of acute leukemia and myelodysplastic syndrome (MDS). A T-cell receptor (TCR) that specifically reacts with WT1 peptide in the context of HLA-A*24:02 has been identified. We conducted a first-in-human trial of TCR-gene transduced T-cell (TCR-T-cell) transfer in patients with refractory acute myeloblastic leukemia (AML) and high-risk MDS to investigate the safety and cell kinetics of the T cells. The WT1-specific TCR-gene was transduced to T cells using a retroviral vector encoding small interfering RNAs for endogenous TCR genes. The T cells were transferred twice with a 4-week interval in a dose-escalating design. After the second transfer, sequential WT1 peptide vaccines were given. Eight patients, divided into 2 dose cohorts, received cell transfer. No adverse events of normal tissue were seen. The TCR-T cells were detected in peripheral blood for 8 weeks at levels proportional to the dose administered, and in 5 patients, they persisted throughout the study period. The persisting cells maintained ex vivo peptide-specific immune reactivity. Two patients showed transient decreases in blast counts in bone marrow, which was associated with recovery of hematopoiesis. Four of 5 patients who had persistent T cells at the end of the study survived more than 12 months. These results suggest WT1-specific TCR-T cells manipulated by ex vivo culture of polyclonal peripheral lymphocytes survived in vivo and retained the capacity to mount an immune reaction to WT1. This trial was registered at www.umin.ac.jp as #UMIN000011519.

HLA 1-locus-mismatched unrelated donors (1MMUD) have been used in allogeneic hematopoietic stem cell transplantation (allo-HCT) for patients who lack an HLA-matched donor. We retrospectively analyzed 3313 patients with acute leukemia or myelodysplastic syndrome who underwent bone marrow transplantation from an HLA allele-matched unrelated donor (MUD) or 1MMUD between 2009 and 2014. We compared the outcomes of MUD (n=2089) and 1MMUD with antithymocyte globulin (ATG) (1MM-ATG(+); n=109) with those of 1MMUD without ATG (1MM-ATG(−); n=1115). The median total dose of ATG (thymoglobulin) was 2.5 mg/kg (range 1.0–11.0 mg/kg) in the 1MM-ATG(+) group. The rates of grade III–IV acute GvHD, non-relapse mortality (NRM) and overall mortality were significantly lower in the MUD group than in the 1MM-ATG(−) group (hazard ratio (HR) 0.77, P=0.016; HR 0.74; P

To investigate better GVHD prophylaxis in reduced intensity conditioning umbilical cord blood transplantation (RIC-UCBT), we compared transplant outcomes after UCBT among GvHD prophylaxes using the registry data. We selected patients transplanted for AML or ALL with a calcineurin inhibitor and methotrexate (MTX)/mycophenolate mofetil (MMF) combination. A total of 748 first RIC-UCBT between 2000 and 2012 (MTX+ group, 446, MMF+ group, 302) were included. The cumulative incidence of neutrophil and platelet counts higher than 50 000/μL was significantly better in the MMF+ group (relative risk (RR), 1.55; P

The effect of GVHD on transplant outcomes after unrelated cord blood transplantation (UCBT) is not yet fully understood. Pediatric patients aged 0–15 years with acute leukemia or myelodysplastic syndrome who underwent their first UCBT (n = 740) were selected from the Japanese registry. Fifty percent of the patients received a UCB unit containing more than 5.0 × 107/kg total nucleated cells. The occurrence of grade III–IV acute GVHD was associated with a higher risk of non-relapse mortality (NRM, hazard ratio [HR] 4.07, P

Induced pluripotent stem cells (iPSCs) have been applied to clinical regenerative cell therapy. Recently, an iPSC banking system to collect HLA haplotype (HP) homozygous (homo) cells for iPSC transplantation in allogeneic settings was proposed, and tissue transplantation generated from iPSC through banking has just began. We analyzed 5017 single cord blood transplantation (CBT) pairs with HLA-A, -B, -C, -DRB1 allele typing data and found 39 donor HLA homo donor to patient HLA heterozygous (hetero) pairs. Of note, all 39 HLA homo to hetero pairs engrafted neutrophils, except 1 early death pair, and all 30 assessable pairs engrafted platelets. Acute graft-versus-host disease (GVHD) grades II to IV and grades III to IV occurred in 17 and 3 of 38 assessable pairs, respectively. Competing risk regression analysis revealed a favorable risk of neutrophil engraftment and higher risk of acute GVHD compared with HLA-matched CBTs. Thirty-seven of 39 homo to hetero pairs had conserved extended HLA HPs (HP-1, n = 18; HP-2, n = 8; HP-3, n = 7; HP-4, n = 4; HP-5, n = 1) that were ethnicity-specific, and at least 1 of 2 patient HLA-A, -B, -C, and -DRB1 alleles in each locus were invariably shared with the same donor HP in 35 pairs. These findings confirmed our preliminary results with 6 HLA homo CBTs, and a trend of high incidence of acute GVHD was newly observed. Importantly, they imply the possibility that HLA-homo iPSC transplantation provides favorable engraftment and accordingly imply the merit of banking iPSC with homozygous major conserved extended HLA HPs.

Ganciclovir (GCV) and foscarnet (FCN) are effective anti-cytomegalovirus (CMV) preemptive therapies; however, the impact of the 2 agents on various clinical outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) remains unclear. We retrospectively analyzed data on 532 patients undergoing allogeneic HSCT from unrelated donors and administered FCN (n = 86) or GCV (n = 446) as first-line anti-CMV preemptive therapy. Overall survival, relapse, and nonrelapse mortality (NRM) did not differ between the FCN and GCV groups, whereas the GCV group had a higher risk of chronic graft-versus-host disease (cGVHD) (hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.28 to 4.39; P = .006) and extensive cGVHD (HR, 3.94; 95% CI, 1.43 to 10.9; P = .008). All 13 patients with cGVHD in the FCN group survived. Switching to the other agent was done mainly due to hematologic adverse events in the GCV group and mainly due to insufficient efficacy in the FCN group. The incidence of end-organ CMV disease was similar in the 2 groups. Selection of FCN or GCV as first-line preemptive anti-CMV therapy did not affect survival, relapse, or NRM. Physicians can select either of the agents, depending on the clinical situation; however, the selection may influence the cGVHD-related clinical course in HSCT recipients.

In order to examine GvHD prophylaxis in umbilical cord blood transplantation (UCBT) in more detail, we compared transplant outcomes after UCBT for acute leukemia among GvHD prophylaxes using registry data. We selected patients transplanted with a calcineurin inhibitor and methotrexate (MTX)/mycophenolate mofetil (MMF) combination. A total of 1516 first myeloablative UCBT between 2000 and 2012 (Cyclosporine A (CyA) plus MTX, 824, Tacrolimus (Tac) plus MTX, 554, Tac plus MMF, 138) were included. With adjusted analyses, Tac plus MMF showed a significantly higher risk for grade II-IV and III-IV acute GvHD than CyA or Tac plus MTX. Although NRM was similar, Tac plus MMF showed a significantly lower risk of relapse than CyA or Tac plus MTX. A significant difference was observed in the risk of overall mortality (OM) between the MTX-containing group and MMF-containing group. In patients with standard-risk disease, there was no significant difference in the risk of OM in any GvHD prophylaxis. However, in patients with advanced-risk disease, Tac plus MMF showed a significantly lower risk of OM. Therefore, MTX-containing prophylaxis is preferred in UCBT for standard-risk disease, whereas MMF-containing prophylaxis is preferred for advanced-risk disease. A prospective study to identify optimal GvHD prophylaxis for UCBT is warranted.

We conducted a retrospective registry-based study involving 198 patients with acute promyelocytic leukemia (APL) who underwent autologous hematopoietic cell transplantation (HCT) during second complete remission (CR2) from 1995 to 2012. Arsenic trioxide (ATO) became commercially available in Japan in December 2004, and a substantial increase in the annual numbers of transplantations has occurred since 2005. Patients transplanted after 2006 had significantly better relapse-free and overall survival than those transplanted before 2004 (p = .028 and p = .027, respectively). There was a significant difference in cumulative incidence of relapse in favor of those transplanted after 2006 (p = .008), whereas non-relapse mortality did not differ between the two groups (p = .683). Our findings suggest that the introduction of ATO may have reduced post-transplantation relapse without increasing non-relapse mortality, resulting in significant improvements in overall outcomes for relapsed APL patients undergoing autologous HCT during CR2.

The risk of acute graft-versus-host disease (GVHD) after HLA-matched sibling bone marrow transplantation (BMT) is lower in Japanese than in Caucasian patients. However, race may have differential effect on GVHD dependent on the graft source. North American Caucasian and Japanese patients receiving their first allogeneic BMT or peripheral blood stem cell transplantation from an HLA-matched sibling for leukemia were eligible. BMT was performed in 13% of the Caucasian patients and in 53% of the Japanese patients. On multivariate analysis, the interaction term between race and graft source was not significant in any of the models, indicating that graft source does not affect the impact of race on outcomes. The risk of grade III or IV acute GVHD was significantly lower in the Japanese patients compared with the Caucasian patients (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57 to 0.96), which resulted in lower risk of nonrelapse mortality in the Japanese patients (HR, 0.69; 95% CI, 0.54 to 0.89). The risk of relapse was also lower in this group. The lower risks of nonrelapse mortality and relapse resulted in lower overall mortality rates among the Japanese patients. In conclusion, our data indicate that irrespective of graft source, the risk of severe acute GVHD is lower in Japanese patients, resulting in a lower risk of nonrelapse mortality.

Introduction and Objectives Regulatory T cells (Treg) play a central role in the maintenance of immune tolerance. We previously reported that the altered Treg homeostasis in the prolonged lymphopenia after HSCT is one of the major pathogenesis of impaired Treg recovery leading to the onset of chronic GVHD and low-dose IL-2 can restore normal Treg homeostasis by a PD-1-dependent mechanism, resulting in the improvement of clinical GVHD symptoms. In these years, the tolerogenic effects of IL-2 have been tested for various autoimmune diseases by clinical trials. However, the schedules of IL-2 dosing in each trial are different and the optimal strategy to expand Treg is still unclear. Our murine study has shown that daily administration of IL-2 seems to be optimal for the initial expansion of Treg but less frequent dosing within the threshold could be preferable for the following maintenance of expanded Treg. Methods Based on the findings, we conducted a phase1/2a clinical trial of low-dose IL-2 for steroid-refractory chronic GVHD with a distinctive dosing schedule consisting of an initial induction phase (IL-2 dosing everyday for the first 4 weeks) and a subsequent maintenance phase (IL-2 dosing 3 times a week for the following 8 weeks). Patients who obtained clinical benefit by the 3 months could proceed to the extended therapy up to total 12 months. The appropriate single dose of IL-2 was examined by a three-step dose escalation design. Results A total of 12 patients were enrolled. None had progression of chronic GVHD or recurrent hematologic malignancy. Dose-limiting toxicity did not occur even at the maximum dose. All patients were evaluable for response, and 7 had clinically significant responses involving multiple sites. Response was observed most often in the joints (67%). One patient with oral GVHD and another patient with gastrointestinal GVHD achieved complete response. One patient with severe lung GVHD markedly improved pulmonary functional test (%FEV1; from 24.8% to 64.8 %) and activity of daily life (from bedridden to return to work). Treg were preferentially increased in all patients, with a peak median value almost 10 times the baseline value (P Conclusion These results indicate that the sustained efficacy of IL-2 against chronic GVHD does not necessarily require that Treg is maintained at a high level by continuing daily IL-2 administration over the long term. Our data provide important information for reconsidering IL-2 dosing methods from the viewpoint of long-term safety and possible combination with other treatments.

The choice of alternative donor is a major issue in allogeneic hematopoietic stem cell transplantation (HSCT) for patients with primary myelofibrosis (PMF) without an HLA-matched related donor. We conducted this retrospective study using the Japanese national registry data for 224 PMF patients to compare the outcomes of first allogeneic HSCT from HLA-matched related donor bone marrow (Rtd-BM), HLA-matched related donor peripheral blood stem cells (Rtd-PB), HLA-matched unrelated donor bone marrow (UR-BM), unrelated umbilical cord blood (UR-UCB), and other hematopoietic stem cell grafts. Nonrelapse mortality (NRM) rates at 1 year after Rtd-BM, Rtd-PB, UR-BM, UR-UCB, and other transplantations were 16%, 36%, 30%, 41%, and 48%, respectively. Multivariate analysis identified UR-UCB transplantation, other transplantation, frequent RBC transfusion before transplantation, and frequent platelet (PLT) transfusion before transplantation as predictive of higher NRM. Relapse rates at 1 year after Rtd-BM, Rtd-PB, UR-BM, UR-UCB, and other transplantation were 14%, 17%, 11%, 14%, and 15%, respectively. No specific factor was associated with the incidence of relapse. Overall survival (OS) at 1 and 4 years after Rtd-BM, Rtd-PB, UR-BM, UR-UCB, and other transplantation were 81% and 71%, 58% and 52%, 61% and 46%, 48% and 27%, and 48% and 41%, respectively. Multivariate analysis identified older patient age, frequent RBC transfusion before transplantation, and frequent PLT transfusion before transplantation as predictive of lower OS. In conclusion, UR-UCB transplantation, as well as UR-BM transplantation, can be selected for PMF patients without an HLA-identical related donor. However, careful management is required for patients after UR-UCB transplantation because of the high NRM. Further studies including more patients after HLA-haploidentical related donor and HLA-mismatched unrelated donor transplantation would provide more valuable information for patients with PMF when making decisions regarding the choice of alternative donor.

Following a phase I/II study using mesenchymal stem cells (MSCs; JR-031) for steroid-refractory grade II or III acute graft-versus-host disease (aGVHD), a phase II/III study using the cells focused on steroid-refractory grade III or IV aGVHD was conducted. The number of infused MSCs and the number of MSC infusions were the same as the phase I/II study. No additional immunosuppressant was given for steroid-refractory aGVHD during the course of MSC infusions. Twenty-five patients (grade III, 22 patients and grade IV, 3 patients) were enrolled in this study. At 4 weeks after the first MSC infusions, six (24 %) and nine patients (36 %) achieved a complete response (CR) and partial response (PR), respectively. Durable CR by 24 weeks, which was the primary end-point, was obtained in 12 of 25 patients (48 %). At 52 weeks, 12 patients (48 %) treated with MSCs only (six patients) and MSCs plus additional treatments (six patients) were alive in CR. The survival was significantly better in patients showing overall response (OR; CR+PR) than in those showing no OR at 4 weeks. Adverse effects commonly associated with MSC infusions were not observed. Taken together, our two clinical trials suggest JR-031 to be effective for steroid-refractory aGVHD.

Influence of melphalan plus fludarabine-conditioning regimen in elderly patients aged ⩾ 55 years with hematological malignancies

Hepatic acute GvHD (aGvHD) is associated with high mortality owing to poor response to immunosuppressive therapy. The pathogenesis of hepatic aGvHD differs from that of other lesions, and specific risk factors related to pre-transplant liver conditions should be determined. We conducted a cohort study by using a Japanese transplant registry database (N=8378). Of these subjects, 1.5% had hepatitis C virus Ab (HCV-Ab) and 9.4% had liver dysfunction (elevated transaminase or bilirubin levels) before hematopoietic cell transplantation (HCT). After HCT, the cumulative incidence of hepatic aGvHD was 6.7%. On multivariate analyses, HCV-Ab positivity (hazard ratio (HR), 1.93; P=0.02) and pre-transplant liver dysfunction (HR, 1.85; P

Little is known regarding the chimerism status after reduced-intensity conditioning transplantation when bone marrow is used as a stem cell source. We prospectively analyzed lineage-specific chimerism and retrospectively evaluated clinical outcomes in 80 adult patients who underwent unrelated donor bone marrow transplantation (URBMT) with fludarabine plus melphalan (FM) as the conditioning regimen. Mixed donor chimerism (MDC) was seen in 43 and 10 % of patients at days 14 and 28, respectively. Melphalan at ≤130 mg/m(2) was associated with an increased incidence of MDC at day 28 (P = 0.03). Patients with MDC at day 14 showed a marginally increased risk of primary graft failure and a marginally decreased risk of graft-versus-host disease. In multivariate analysis, MDC at day 14 was associated with higher overall mortality (hazard ratio (HR) = 2.1; 95 % confidence interval (CI), 1.1-4.2; P = 0.04) and relapse rate (HR = 3.0; 95 % CI, 1.2-7.5; P = 0.02), but not with non-relapse mortality (HR = 1.8; 95 % CI, 0.70-4.6; P = 0.23). Thus, the FM regimen yields prompt complete donor chimerism after URBMT, but the melphalan dose significantly impacts the kinetics of chimerism. Chimerism status evaluation at day 14 may be instrumental in predicting relapse after URBMT with the FM regimen.

We retrospectively analyzed 2682 patients who developed grade II-IV acute graft-versus-host disease (GVHD). On analysis with stratification into five age groups (20-29, 30-39, 40-49, 50-59 and ≥60), 2-year non-relapse mortality rates (NRM) after the onset of GVHD were 20.7, 26.2, 26.6, 37.0 and 40.4%, respectively (p

Graft-versus-host disease (GVHD) occasionally leads to morbidity and mortality but is thought to reduce the risk of relapses in patients with a hematological malignancy. However, information on the effect of GVHD in pediatric leukemia is limited. Using a nationwide registry, we retrospectively analyzed 1526 children who underwent allogeneic stem cell transplantation for leukemia. Grades 0-I acute GVHD were associated with a higher relapse rate at three years after transplantation, at 25.4 and 24.3%, respectively, than grades II, III, or IV acute GVHD at 18.9%, 21.2%, and 2.6%, respectively. In contrast, the overall survival curve of the grades 0 and I GVHD groups (79.0% and 79.5%, respectively) approximated that of the grade II GVHD group (76.3%), and the probability of survival was worst in the severe GVHD groups (66.9% for grade III and 42.5% for grade IV). Chronic GVHD also reduced the relapse risk but conferred no survival advantage. Acute lymphoblastic leukemia was more sensitive to acute GVHD than acute myeloid leukemia (AML) while AML was more sensitive to chronic GVHD. Our study reproduced the preventive effects of GVHD against pediatric leukemia relapses but failed to demonstrate a significant survival advantage.

Impact of T-cell chimerism on relapse after cord blood transplantation for hematological malignancies: Nagoya Blood and Marrow Transplantation Group study

Allogeneic bone marrow and peripheral blood stem cell transplantations are curative treatment modalities for adult T cell leukemia/lymphoma (ATLL) because of the intrinsic graft-versus-ATLL effect. However, limited information is available regarding whether cord blood transplantation (CBT) induces a curative graft-versus-ATLL effect against aggressive ATLL. To evaluate the effect of CBT against ATLL, we retrospectively analyzed data from 175 patients with ATLL who initially underwent single-unit CBT. The 2-year overall survival (OS) rate was 20.6% (95% confidence interval [CI], 13.8% to 27.4%). A multivariate analysis revealed that the development of graft-versus-host disease (GVHD) was a favorable prognostic factor for OS (hazard ratio, .10; 95% CI, .01 to .94; P = .044). Furthermore, the 2-year OS (42.7%; 95% CI, 28.1% to 56.6%) of patients with grade 1 to 2 acute GVHD was higher than that of patients without acute GVHD (24.2%; 95% CI, 11.2% to 39.8%; P = .048). However, the cumulative incidence of treatment-related mortality (TRM) was high (46.1%; 95% CI, 38.2% to 53.7%), and early death was particularly problematic. In conclusion, CBT cures patients with ATLL partly through a graft-versus-ATLL effect. However, novel interventions will be required, particularly in the early phase, to reduce TRM and optimize GVHD.

Background Cyclosporine A (CsA) is used widely for graft-versus-host disease (GVHD) prophylaxis in hematopoietic stem cell transplantation (HSCT); however, the optimal schedule of its administration has not been established. Although comparative studies of adult patients undergoing HSCT have demonstrated enhanced efficacy and safety of twice-daily infusion (TD) compared with continuous infusion (CIF) of CsA, to our knowledge, similar studies have not yet been performed in pediatric groups. Procedure A self-administered questionnaire was used to retrospectively compare the clinical outcome and incidence of CsA-associated adverse events of 70 pediatric acute myelogenous leukemia patients who were receiving CsA by TD (n = 36) or CIF (n = 34) as GVHD prophylaxis for their first allogeneic HSCT. Results The cumulative incidences of grade II–IV acute GVHD and chronic GVHD, as well as the overall survival and event-free survival rates, did not differ significantly between the TD and CIF groups; however, the incidence of severe hypertension was significantly higher in the CIF group than the TD group. Conclusions The analysis presented here indicates that TD and CIF administration of CsA have similar prophylactic effect on pediatric GVHD and suggest that TD is associated with a lower rate of toxicity than CIF in pediatric patients undergoing HSCT. Pediatr Blood Cancer 2015;62:291–298. © 2014 Wiley Periodicals, Inc.

Background: Delayed hematological recovery, graft failure, and acute graft-versus-host disease (GVHD) remain major problems in cord blood transplantation (CBT). Mesenchymal stem cells (MSCs) are known to support bone marrow (BM) stroma and promote hematopoiesis. Additionally, MSCs possess immunomodulatory properties and are used clinically for the treatment of acute GVHD. Therefore, the use of MSCs to enhance engraftment and prevent GVHD after allogeneic hematopoietic cell transplantation has been explored. Recent clinical trials have shown the safety and feasibility of CBT with intravenous co-transplantation of MSCs in pediatric patients (pts), but not in adults, who are at greater risk of graft failure. Previous preclinical study showed that direct intra-BM injection of MSCs enhanced the engraftment of CB cells more than intravenous injection. Based on these backgrounds, to develop a new strategy not only to enhance engraftment but also to prevent GVHD, we designed a first phase I clinical trial to evaluate the safety of CBT combined with intra-BM injection of MSCs (MSC-CBT) for adults (UMIN-CTR, number 000024291). Methods: This study was a single arm, non-randomized, open-label, single-center, phase I trial. Adult pts with hematological disorders were eligible for this study. The target sample size was 5. MSCs were expanded from BM mononuclear cells harvested from healthy adult donors who were patient's spouse or relative within the fourth degree of relationship. The target dose of MSCs infused was 0.5×106 cells/kg of patient body weight. On the day of CBT, MSCs were injected into the intra-BM of the patient 4 hours before the infusion of a single CB unit. The conditioning regimen varied according to patient characteristics. GVHD prophylaxis was tacrolimus and methotrexate. The primary endpoint of this study was toxicity related to intra-BM injection of MSCs within 14 days after transplantation. Hematopoietic recoveries, clinical outcomes, lymphocyte subsets, and cytokine/chemokine levels were compared with controls (n=6) who received CBT without MSC during same time period in our institute. Results: Between February 2017 and June 2018, 6 pts were enrolled, but one did not meet the criteria for release of MSCs due to insufficient cell counts. Among 5 eligible pts, the median age was 47 years (range, 24-70 years). Four pts (80%) were male. Two pts (40%) had AML in 1st or 2nd CR, 2 (40%) had MDS-EB-2, and one (20%) had malignant lymphoma in 1st remission. The median number of cryopreserved TNCs and CD34+ cells in a CB unit was 2.6 × 107/kg (range, 1.9-4.3 × 107/kg) and 1.0 × 105/kg (range, 0.7-1.2 × 105/kg), respectively. No pts had donor-specific HLA antibodies. All pts received myeloablative conditioning regimen. There was no significant difference between pts and controls in these characteristics. The median number of MSCs was 1.4 × 106/kg (range, 0.3-1.8 × 106/kg). No adverse events related to intra-BM injection of MSCs were observed. All pts achieved neutrophils ≥0.5 × 109/L, reticulocytes ≥1%, platelets ≥20 × 109/L , and platelets ≥50 × 109/L recoveries, with median time to recoveries of 21 (range, 17-27), 35 (range, 29-39), 38 (range, 29-48), and 52 (range, 42-57) days after transplantation, respectively. There was no difference in hematopoietic recoveries compared to controls. Grade II-IV acute GVHD developed in 3 controls (50%); however, there was no grade II-IV acute GVHD in MSC-CBT pts (Fig. 1). No pts developed chronic GVHD in both groups. At 1 year after transplantation, 2 controls developed relapse and 1 died for relapse, whereas all MSC-CBT pts survived without relapse. T and NK cell counts at 28 days after transplantation in MSC-CBT pts had tendencies to be higher compared to controls, with median cell counts of 166 (range, 21-351) vs. 25 (range, 3-120) cells/μL (P=0.09) and 107 (range, 78-168) vs. 61 (range, 11-117) cells/μL (P=0.06), respectively (Fig. 2). There were tendencies to decrease in IFN-γ, IL-21, IL-1α, IL-2, and IL-4 levels within 28 days after transplantation in MSC-CBT pts compared to controls (Fig. 3). Conclusions: The present study shows the safety of CBT combined with intra-BM injection of MSCs. Our findings also suggest that co-transplantation of MSCs may prevent GVHD, accompanied by decrease in some inflammatory cytokines, whereas may enhance immune reconstitutions. Further analysis is required to confirm the efficacy of co-transplantation of MSCs. Disclosures Goto: JCR Pharmaceuticals Co., Ltd.: Honoraria; Celgene Co., Ltd.: Honoraria; Novartis Pharma Co., Ltd.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria. Murata:Chugai Pharmaceutical Co., Ltd.: Honoraria; JCR Pharmaceuticals Co., Ltd.: Honoraria; Novartis Pharma Co., Ltd.: Honoraria; Astellas Pharma Inc.: Honoraria; Kyowa-Hakko Kirin Co., Ltd.: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; Celgene Co., Ltd.: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Consultancy, Honoraria; Bristol-Myers Squibb, Ltd.: Honoraria; GSK Co., Ltd.: Consultancy; MSD Co., Ltd.: Honoraria. Nishida:Amgen Astellas BioPharma K.K.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria; MSD K.K.: Consultancy, Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Honoraria. Terakura:Sumitomo Dainippon Pharma: Honoraria; Novartis: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; Yakult Honsha, Co., Ltd.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Astellas Pharma Inc.: Honoraria; Amgen Astellas BioPharma K.K.: Honoraria. Ishikawa:Bristol-Myers Squibb: Honoraria; Celgene Co., Ltd.: Honoraria; Kyowa Hakko Kirin Co., Ltd.: Honoraria; Abbvie GK.: Honoraria. Matsushita:CSL: Consultancy, Honoraria; Bioverative: Research Funding; Novo Nordisk: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; KM biologists: Consultancy, Honoraria, Research Funding; uniQure: Consultancy, Honoraria. Kiyoi:Bristol-Myers Squibb: Research Funding; FUJIFILM Corporation: Research Funding; Nippon Shinyaku Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Perseus Proteomics Inc.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Zenyaku Kogyo Co., Ltd.: Research Funding; Astellas Pharma Inc.: Honoraria, Research Funding; Otsuka Pharmaceutical Co.,Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Pfizer Japan Inc.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Research Funding; Daiichi Sankyo Co., Ltd: Research Funding.

Background: Among HLA-well-matched unrelated donor (UD) and umbilical cord blood (CB), HLA-8/8 allele-matched UD transplantation (UDT) showed superior overall survival (OS) to 7/8 allele-matched UDT and CBT, while a similar OS has been demonstrated between the HLA-7/8 allele-matched UDT and the CBT. However, a fair comparison between UDT and CBT is difficult, because graft availability and time required for donor-search is completely different. Once patients relapsed during UD-search period, most of those patients would choose immediate CBT. This means that patients who maintained CR in UD group may have more favorable characteristics, because those patients have been longer in remission and selected as a group of patients who maintained CR. Thus we thought that the factor of "donor-search duration" is important upon conducting a comparative study between UDT and CBT. We planned a clinical study that also taken "donor-search duration" into consideration to compare CBT outcomes with HLA well-matched UDT in a prospective trial setting. Purpose: The purpose of the current study is to compare the transplant outcomes of HLA-well-matched UDT with those of CBT in a prospective trial. Patients and Methods: From 2007 to 2015, 231 patients were provisionally registered for a single-arm phase 2 study of CBT (manuscript submitted). All provisionally registered patients were subjects of current study (Figure 1). After provisional registration, we attempted to find appropriate UD within a decent time period. After approximately 180 days of donor-search, patients received CBT if an appropriate UD was not available. In total, 91 patients received UDT, and 119 patients received CBT. Six patients withdrew and three died before transplantation. Twelve patients did not receive either UDT or CBT, but five received HLA-mismatched SCT from family donor (seven chose not to receive allogeneic SCT). Of 119 CBT recipients, 62 patients were eligible and registered to a phase 2 clinical trial reported elsewhere. Herein we analyzed transplant outcomes of 91 UDT and 119 CBT (UDT group; 49 AML, 37 ALL, 5 MDS: CBT group; 68 AML, 38 ALL, 13 MDS). Risk factors were analyzed by cox proportional hazard model, and survival estimates were depicted by Kaplan-Meier estimation and tested by log-rank test. Results: Patient age was median 39 yrs in both UDT and CBT (p=0.80). Patient body weight was median 59kg (37-90kg) in UDT, and median 55kg (35-90kg) in CBT (p=0.10). Sixty-six of 91 (72.5%) in UDT and 114 of 119 (95.8%) in CBT received myeloablative conditioning. More than 90% of patients received Tacrolimus and short-term methotrexate as GVHD prophylaxis in both UDT and CBT. Days from provisional registration to transplant were median 126 days (range, 77-261 days) in UDT, and median 99 days (8-286 days) in CBT (p Conclusion: Taken donor-search period into consideration, OS after UDT and CBT were similar in a prospective clinical study. CB may be the comparable alternative donor source to UDT. Disclosures Terakura: Novartis: Honoraria; Astellas Pharma Inc.: Honoraria; Amgen Astellas BioPharma K.K.: Honoraria; Sumitomo Dainippon Pharma: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Yakult Honsha, Co., Ltd.: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria. Nishida:Sumitomo Dainippon Pharma Co., Ltd.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria; MSD K.K.: Consultancy, Honoraria; Amgen Astellas BioPharma K.K.: Honoraria. Sawa:Mundi Pharma: Honoraria; Bristol-Myers Squibb: Honoraria; Sumitomo Dainippon Pharma: Honoraria; Sanofi: Honoraria; Astellas Pharma Inc.: Honoraria; Ono Pharmaceutical Co., Ltd: Honoraria; Otsuka Pharmaceutical: Honoraria; Kyowa-Hakko Kirin: Honoraria; Novartis: Honoraria; Shire: Honoraria; Eisai: Honoraria; Mochida: Honoraria; Pfizer Japan Inc.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Nippon Shinyaku: Honoraria; MSD: Honoraria; Asahi-Kasei: Honoraria; Takeda: Honoraria; Celgene: Honoraria. Miyao:Bristol-Myers Squibb: Honoraria; Celgene Corporation: Honoraria; Novartis: Honoraria. Ozawa:Pfizer Japan Inc.: Honoraria; Kyowa-Hakko Kirin: Honoraria; Astellas Pharma Inc.: Honoraria; Novartis: Honoraria. Goto:Celgene Co., Ltd.: Honoraria; JCR Pharmaceuticals Co., Ltd.: Honoraria; Novartis Pharma Co., Ltd.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria. Onishi:Sumitomo Dainippon Pharma: Honoraria; Janssen Pharmaceutical K.K.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; ONO PHARMACEUTICAL CO., LTD.: Honoraria; Nippon Shinyaku: Honoraria; Kyowa-Hakko Kirin: Honoraria; Pfizer Japan Inc.: Honoraria; Astellas Pharma Inc.: Honoraria; Celgene: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; Novartis Pharma: Honoraria; Takeda Pharmaceutical Co., Ltd.: Research Funding; MSD: Honoraria, Research Funding. Fukuhara:Janssen Pharma: Honoraria; Eisai: Honoraria, Research Funding; Chugai Pharmaceutical Co., Ltd.: Honoraria; AbbVie: Research Funding; Celgene Corporation: Honoraria, Research Funding; Zenyaku: Honoraria; Bayer: Research Funding; Nippon Shinkyaku: Honoraria; Kyowa-Hakko Kirin: Honoraria; Mochida: Honoraria; Mundi: Honoraria; Ono Pharmaceutical Co., Ltd.: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Gilead: Research Funding; Solasia Pharma: Research Funding. Fujii:Novartis Pharma Co., Ltd.: Honoraria; Kyowa-Hakko Kirin Co., Ltd.: Honoraria. Iida:Chugai Pharmaceutical Co., Ltd.: Research Funding. Endo:Ono: Research Funding. Onizuka:Sumitomo Dainippon Pharma: Research Funding; Astellas: Research Funding; Novartis: Research Funding; pfizer: Research Funding; Chugai Pharma: Research Funding; Bristol-Myers Squibb: Research Funding. Iyama:Otsuka Pharmaceutical Co., Ltd.: Honoraria; Otsuka Pharmaceutical Factory: Honoraria; Astellas Pharma: Honoraria; Daiichi Sankyo: Honoraria; Allexion Pharma: Honoraria; CSL Behring: Honoraria. Nakamae:Japan Blood Products Organization: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kyowa-Hakko Kirin Co.,Ltd: Honoraria; Nippon Shinyaku: Honoraria; Bristol-Myers Squibb: Honoraria; Shire Japan KK.: Honoraria; Pfizer Japan Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma Inc.: Research Funding; Alexion: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Novartis: Honoraria, Research Funding; Takeda Pharmaceutical Co., Ltd.: Honoraria. Nagata:Janssen Pharmaceutical K.K.: Honoraria; Bristol-Myers Squibb K.K.: Honoraria; Ono Pharmaceutical Co., Ltd: Honoraria; Novartis Pharma K.K.: Honoraria; Celgene K.K.: Honoraria; Takeda Pharmaceutical Co., Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kurahashi:Novartis Pharma Co., Ltd.: Honoraria; Bristol-Myers Squibb, Ltd.: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Honoraria; Takeda Pharmaceutical Co., Ltd: Honoraria. Suzuki:Celgene: Honoraria; Eisai: Honoraria; Novartis: Honoraria; Bristol-Myers Squibb: Honoraria; Kyowa Hakko Kirin: Honoraria; Chugai Pharmaceutical Co.,Ltd.: Honoraria; Meiji Seika: Honoraria; Merck Sharp & Dohme: Honoraria; Takeda Pharmaceutical Co., Ltd.: Honoraria; ONO Pharmaceutical Co., Ltd.: Honoraria; Janssen: Honoraria; AbbVie: Honoraria. Atsuta:Mochida Pharmaceutical Co. Ltd: Honoraria; Kyowa Kirin Co., Ltd: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Janssen Paharmaceutical K.K.: Honoraria. Miyamura:Bristol-Myers Squibb: Honoraria; Novartis: Honoraria; Pfizer Japan Inc.: Honoraria; Otsuka Pharmaceutical: Honoraria; Takeda Pharmaceutical: Honoraria; Kyowa-Hakko Kirin Co., Ltd: Honoraria; CHUGAI PHARMACEUTICAL CO., LTD.: Honoraria; Astellas Pharma Inc.: Honoraria; Celgene: Honoraria. Murata:Bristol-Myers Squibb, Ltd.: Honoraria; Kyowa-Hakko Kirin Co., Ltd.: Honoraria; Celgene Co., Ltd.: Honoraria; Sumitomo Dainippon Pharma Co., Ltd.: Consultancy, Honoraria; GSK Co., Ltd.: Consultancy; Astellas Pharma Inc.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; JCR Pharmaceuticals Co., Ltd.: Honoraria; Novartis Pharma Co., Ltd.: Honoraria; MSD Co., Ltd.: Honoraria.

To determine whether a difference in donor source affects the outcome of transplantation for patients with primary myelofibrosis (PMF), a retrospective study was conducted using the national registry data on patients who received first allogeneic hematopoietic cell transplantation (HCT) with related BM (n=19), related PBSCs (n=25), unrelated BM (n=28) or unrelated umbilical cord blood (UCB; n=11). The 5-year OS rates after related BM, related PBSC and unrelated BM transplantation were 63%, 43% and 41%, respectively, and the 2-year OS rate after UCB transplantation was 36%. On multivariate analysis, the donor source was not a significant factor for predicting the OS rate. Instead, performance status (PS) ⩾2 (vs PS 0–1) predicted a lower OS (P=0.044), and RBC transfusion ⩾20 times before transplantation (vs transfusion ⩽9 times) showed a trend toward a lower OS (P=0.053). No advantage of nonmyeloablative preconditioning regimens in terms of decreasing nonrelapse mortality or increasing OS was found. Allogeneic HCT, and even unrelated BM and UCB transplantation, provides a curative treatment for PMF patients.

Few studies have evaluated the risk factors for chronic GVHD and organ involvement associated with different graft types, including unrelated cord blood (U-CB). We retrospectively studied 4818 adult patients who received their first allogeneic transplantation and survived for at least 100 days. The incidence of chronic GVHD at 2 years was 37%. The following factors were associated with the development of chronic GVHD: female donor/male recipient, CMV-Ab seropositivity, matched related peripheral blood grafts vs matched related BM grafts, no in vivo T-cell depletion and the occurrence of grade II-IV acute GVHD. Among these factors, the association with acute GVHD occurrence was consistently significant across donor subtypes. The use of U-CB was not associated with chronic GVHD, but was associated with a low incidence of extensive chronic GVHD. Chronic GVHD patients who had received U-CB transplants showed less frequent involvement of the oral cavity (28% vs 55%), eye (12% vs 26%), liver (20% vs 44%), lung (11% vs 25%) and joint (0% vs 6%) than those with matched related BM grafts. In conclusion, we found that U-CB transplants were associated with a low incidence of extensive chronic GVHD and less frequent involvement of the oral cavity, eye, liver, lung and joints.

We conducted a multicenter phase I/II study using mesenchymal stem cells (MSCs) manufactured from the bone marrow of healthy unrelated volunteers to treat steroid-refractory acute graft-versus-host disease (aGVHD). Fourteen patients with hematological malignancies who suffered from grade II (9 patients) or III aGVHD (5) were treated. Affected organs were gut (10 patients), skin (9 patients), and liver (3 patients). Seven patients had two involved organs. The median age was 52. No other second-line agents were given. MSCs were given at a dose of 2 × 10(6) cells/kg for each infusion twice a week for 4 weeks. If needed, patients were continuously given MSCs weekly for an additional 4 weeks. By week 4, 13 of 14 patients (92.9 %) had responded to MSC therapy with a complete response (CR; n = 8) or partial response (PR; n = 5). At 24 weeks, 11 patients (10 with CR and 1 with PR) were alive. At 96 weeks, 8 patients were alive in CR. A total of 6 patients died, attributable to the following: underlying disease relapse (2 patients), breast cancer relapse (1), veno-occlusive disease (1), ischemic cholangiopathy (1), and pneumonia (1). No clear adverse effects associated with MSC infusion were observed. Third party-derived bone marrow MSCs may be safe and effective for patients with steroid-refractory aGVHD.

The effect of graft-versus-host disease (GVHD) on transplant outcomes after unrelated cord blood transplantation (UCBT) has not been fully elucidated. We analyzed the impact of acute and chronic GVHD on outcomes in adult patients with acute leukemia or myelodysplastic syndrome who underwent their first UCBT (n=2558). The effect of GVHD on outcomes was analyzed after adjusting for other significant variables. The occurrence of GVHD was treated as a time-dependent covariate. The occurrence of grade 1–2 or 3–4 acute GVHD was significantly associated with a lower relapse rate. Grade 3–4 acute GVHD was associated with a higher risk of non-relapse and overall mortality than no acute GVHD, whereas grade 1–2 acute GVHD was associated with a lower risk of non-relapse and overall mortality than no acute GVHD. Limited or extensive chronic GVHD was significantly associated with a lower relapse rate. Limited chronic GVHD was associated with a lower overall and non-relapse mortality than no chronic GVHD. In conclusion, mild acute or chronic GVHD was associated not only with a low risk of relapse but also with a low risk of non-relapse mortality, and provides a survival benefit in UCBT.

A nationwide retrospective study for the clinical outcomes of 99 patients who had received thymoglobulin at a median total dose of 2.5 mg/kg (range, 0.5–18.5 mg/kg) as a second-line treatment for steroid-resistant acute GvHD was conducted. Of the 92 evaluable patients, improvement (complete or partial response) was observed in 55 patients (60%). Multivariate analysis demonstrated that male sex and grade III and IV acute GvHD were associated with a lower improvement rate, whereas thymoglobulin dose (

We have demonstrated that adipose tissue-derived mesenchymal stem cells (ADSCs) from mice are capable of reconstituting the hematopoietic microenvironment, and facilitate hematopoiesis more effectively than bone marrow-derived mesenchymal stem cells (BMSCs) in mouse. The ready accessibility of fat tissue rich in MSCs and the higher hematopoiesis-supporting capacities of ADSCs suggest that ADSCs might represent a new therapeutic modality for the regeneration of impaired hematopoiesis. As a further step towards their use in clinical practice, we established human BMSCs and ADSCs from healthy volunteers of similar age, and compared their proliferation capacities, hematopoiesis-supporting properties, and safety. In vitro cell proliferation studies revealed that ADSCs have a higher population doubling number than BMSCs. In vitro co-culture assays showed that ADSCs not only support human CD34(+) peripheral blood stem cells (PBSCs), but also yield significantly more non-adherent hematic cells than BMSCs. In vitro progenitor assays revealed that ADSCs promote a higher frequency of early progenitors than do BMSCs. Interestingly, BM cellularity in irradiated mice that had received ADSCs tended to be higher than that of mice treated with BMSCs. When MSCs were injected into the BM cavity of tibiae, we observed no evidence of MSC-induced toxicity either during or after treatment. In addition, no microscopic abnormalities were observed in the bone marrow and major organs.

Background Because of the less graft-facilitating effect by bone marrow (BM), we need to assess a dosage of conditioning more accurately particularly in combination with reduced-intensity conditioning. Thus we examined that modified continual reassessment method (mCRM) is applicable for deciding appropriate conditioning of allogeneic BM transplantation. Patients and methods The conditioning regimen consisted of i.v. fludarabine (125 mg/m2) plus an examination dose of i.v. melphalan. The primary endpoint was a donor-type T-cell chimerism at day 28 with successful engraftment defined as >90% donor cells. Five patients per dose level were planned to be accrued and chimerism data were used to determine the next dose. Results Seventeen patients were enrolled at doses between 130 and 160 mg/m2. The dose was changed from 160 to 130 mg/m2 (second level) after five full-donor chimerisms. With one patient of 0% chimera in the second level, the dose was increased to 135 mg/m2 (third level). Following five full-donor chimerisms in the third level, the study was complete as projected. Conclusions mCRM was shown to be a relevant method for dose-finding of conditioning regimen. The melphalan dose of 135 mg/m2 was determined as the recommended phase II dose to induce initial full-donor chimerism.