Differential clinical impact of letermovir prophylaxis according to graft sources: a KSGCT multicenter retrospective analysis.

ABSTRACT: Clinically significant cytomegalovirus infection (csCMVi) is frequently observed after allogeneic hematopoietic stem cell transplantation (HSCT) and prophylaxis with letermovir is commonly adopted. However, the clinical benefit of letermovir prophylaxis according to graft sources has not been sufficiently elucidated. We retrospectively analyzed 2194 recipients of HSCT who were CMV-seropositive (236 with letermovir prophylaxis and 1958 without prophylaxis against CMV). csCMVi was significantly less frequent in patients with letermovir prophylaxis than in those without (23.7% vs 58.7% at 100 days after HSCT, P < .001) and the same trend was seen when recipients of bone marrow (BM), peripheral blood stem cell (PBSC), or cord blood (CB) transplantation were separately analyzed. In recipients of BM, nonrelapse mortality (NRM) was significantly lower in the letermovir group at 6 months after HSCT (5.0% vs 14.9%, P = .018), and the same trend was observed in recipients of PBSCs (14.7% vs 24.8%, P = .062); however, there was no statistical significance at 1 year (BM, 21.1% vs 30.4%, P = .67; PBSCs, 21.2% vs 30.4%, P = .096). In contrast, NRM was comparable between recipients of CB with and without letermovir prophylaxis throughout the clinical course (6 months, 23.6% vs 24.3%, P =.92; 1 year, 29.3% vs 31.0%, P = .77), which was confirmed by multivariate analyses. In conclusion, the impact of letermovir prophylaxis on NRM and csCMVi should be separately considered according to graft sources.

Prognostic factors for the development of lower respiratory tract infection after influenza virus infection in allogeneic hematopoietic stem cell transplantation recipients: A Kanto Study Group for Cell Therapy multicenter analysis.

OBJECTIVES: Influenza virus infection (IVI) occasionally causes lower respiratory tract infection (LRTI) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Although the progression to LRTI entails a high mortality, the role of early antiviral therapy for its prevention has not been fully elucidated. METHODS: This was a multicenter retrospective study using an additional questionnaire. Allo-HSCT recipients who developed IVI between 2012 and 2020 were included. RESULTS: A total of 278 cases of IVI after allo-HSCT were identified from 15 institutions. The median patient age was 49 years, and the median time from allo-HSCT to IVI was 918 days. Neuraminidase inhibitors were administered within 48 hours of symptom onset (early neuraminidase inhibitor [NAI]) in 199 (76.9%) patients. Subsequently, 36 (12.3%) patients developed LRTI. On the multivariate analysis, age ≥50 years (hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.02-4.58) and moderate to severe chronic graft-versus-host disease (HR, 2.28; 95% CI, 1.14-4.58) were significantly associated with progression to LRTI, whereas early NAI suppressed the progression (HR, 0.17; 95% CI, 0.06-0.46). The IVI-related mortality rate was 2.2%. CONCLUSION: To reduce the risk of LRTI development after IVI, early NAI therapy should be considered in allo-HSCT recipients, especially with older patients and those with chronic graft-versus-host disease.

Mutational analysis of DNMT3A improves the prognostic stratification of patients with acute myeloid leukemia.

Nucleophosmin1 (NPM1) mutations are the most frequently detected gene mutations in acute myeloid leukemia (AML) and are considered a favorable prognostic factor. We retrospectively analyzed the prognosis of 605 Japanese patients with de novo AML, including 174 patients with NPM1-mutated AML. Although patients with NPM1-mutated AML showed a high remission rate, this was not a favorable prognostic factor for overall survival (OS); this is contrary to generally accepted guidelines. Comprehensive gene mutation analysis showed that mutations in codon R882 of DNA methyltransferase 3A (DNMT3AR882 mutations) were a strong predicative factor indicating poor prognosis in all AML (p < 0.0001) and NPM1-mutated AML cases (p = 0.0020). Furthermore, multivariate analysis of all AML cases showed that DNMT3AR882 mutations and the co-occurrence of internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD), NPM1 mutations, and DNMT3AR882 mutations (triple mutations) were independent factors predicting a poor prognosis related to OS, with NPM1 mutations being an independent factor for a favorable prognosis (hazard ratios: DNMT3AR882 mutations, 1.946; triple mutations, 1.992, NPM1 mutations, 0.548). Considering the effects of DNMT3AR882 mutations and triple mutations on prognosis and according to the classification of NPM1-mutated AML into three risk groups based on DNMT3AR882 /FLT3-ITD genotypes, we achieved the improved stratification of prognosis (p < 0.0001). We showed that DNMT3AR882 mutations are an independent factor for poor prognosis; moreover, when confounding factors that include DNMT3AR882 mutations were excluded, NPM1 mutations were a favorable prognostic factor. This revealed that ethnological prognostic discrepancies in NPM1 mutations might be corrected through prognostic stratification based on the DNMT3A status.

Outcomes of poor peripheral blood stem cell mobilizers with multiple myeloma at the first mobilization: A multicenter retrospective study in Japan.

Autologous stem cell transplantation (ASCT) remains an important therapeutic strategy for multiple myeloma; however, a proportion of patients fail to mobilize a sufficient number of peripheral blood stem cells (PBSCs) to proceed to ASCT. In the present study, we aimed to clarify the characteristics and outcomes of poor mobilizers. Clinical data on poorly mobilized patients who underwent PBSC harvest for almost 10 years were retrospectively collected from 44 institutions in the Japanese Society of Myeloma (JSM). Poor mobilizers were defined as patients with less than 2 × 106/kg of CD34+ cells harvested at the first mobilization. The proportion of poor mobilization was 15.1%. A sufficient dataset including overall survival (OS) was evaluable in 258 poor mobilizers. Overall, 92 out of 258 (35.7%) poor mobilizers did not subsequently undergo ASCT, mainly due to an insufficient number of PBSCs. Median OS from apheresis was longer for poor mobilizers who underwent ASCT than for those who did not (86.0 vs. 61.9 mon., p = 0.02). OS from the diagnosis of poor mobilizers who underwent ASCT in our cohort was similar to those who underwent ASCT in the JSM database (3y OS rate, 86.8% vs. 85.9%). In this cohort, one-third of poor mobilizers who did not undergo ASCT had relatively poor survival. In contrast, the OS improved in poor mobilizers who underwent ASCT. However, the OS of extremely poor mobilizers was short irrespective of ASCT.

NPM1-mutation-based measurable residual disease assessment after completion of two courses of post-remission therapy is a valuable clinical predictor of the prognosis of acute myeloid leukemia.

Recent studies have reported that measurable residual disease (MRD) analysis using NPM1 mutations helps determine whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) is indicated in acute myeloid leukemia (AML) patients. However, the optimal timing and cutoff value for measuring MRD using genomic DNA remain undetermined. This study aimed to investigate the optimal timing and cutoff value to ascertain the value of NPM1 mutation in MRD assessment. NPM1-mutated MRD was quantified by real-time polymerase chain reaction of bone marrow samples from 56 patients with NPM1-positive AML who achieved hematological remission. The area under the receiver-operating characteristic curve was greatest when MRD was assessed after two courses of post-remission therapy with a cutoff value of 0.010% (specificity, 68.4%; sensitivity, 87.0%). Patients whose MRD was below the cutoff value throughout the course of treatment had significantly better overall survival and relapse-free survival rates. Of the 33 patients who did not undergo transplantation during the first remission, all of the 11 who were never MRD-negative at any point experienced a relapse. Evaluating MRD with a cutoff value of 0.010% after two courses of post-remission therapy helps predict prognosis and determine the indication for allo-HSCT.

Prognostic impact of CEBPA bZIP domain mutation in acute myeloid leukemia.

Mutations of CCAAT/enhancer-binding protein alpha (CEBPAmu) are found in 10% to 15% of de novo acute myeloid leukemia (AML) cases. Double-mutated CEBPA (CEBPAdm) is associated with a favorable prognosis; however, single-mutated CEBPA (CEBPAsm) does not seem to improve prognosis. We investigated CEBPAmu for prognosis in 1028 patients with AML, registered in the Multi-center Collaborative Program for Gene Sequencing of Japanese AML. It was found that CEBPAmu in the basic leucine zipper domain (bZIP) was strongly associated with a favorable prognosis, but CEBPAmu out of the bZIP domain was not. The presence of CEBPAmu in bZIP was a strong indicator of a higher chance of achieving complete remission (P < .001), better overall survival (OS; P < .001) and a lower risk of relapse (P < .001). The prognostic significance of CEBPAmu in bZIP was also observed in the subgroup with CEBPAsm (all patients: OS, P = .008; the cumulative incidence of relapse, P = .063; patients aged ≤70 years and with intermediate-risk karyotype: OS, P = .008; cumulative incidence of relapse, P = .026). Multivariate analysis of 744 patients aged ≤70 years showed that CEBPAmu in bZIP was the most potent predictor of OS (hazard ratio, 0.3287; P < .001). CEBPAdm was validated as a cofounding factor, which was overlapping with CEBPAmu in bZIP. In summary, these findings indicate that CEBPAmu in bZIP is a potent marker for AML prognosis. It holds potential in the refinement of treatment stratification and the development of targeted therapeutic approaches in CEBPA-mutated AML.

Resignation and return to work in patients receiving allogeneic hematopoietic cell transplantation close up.

PURPOSE: To characterize the issues regarding work and employment specific to allogeneic hematopoietic cell transplantation (allo-HCT) survivors, we conducted a nationwide cross-sectional questionnaire survey. METHODS: We targeted allo-HCT survivors employed at diagnosis, aged 20-64 at survey, and survived ≥2 years without relapse. The questionnaire included the timing of and reasons for resignation (termination of employment contract), and patient-related, HCT-related, work-related, and HCT center-related factors. RESULTS: A total of 1048 eligible participants were included in the analysis (response rate, 60%). The median time after allo-HCT was 5 years (range, 2-30) at the time of survey. After diagnosis, 41% of participants resigned from work throughout the course of treatment. The most frequent timing of the first resignation was "after discharge post-HCT" (46%), followed by "from diagnosis to initial treatment" (27%). Factors significantly associated with resignation included female gender, older age, and part-time employment. Favorable factors included the presence of occupational health staff at the workplace, employment of ≥10 years, and self-employed/freelance. After resignation, the overall incidence of return to work with some accommodations was 76% at 5 years after HCT, but it was 52% without any accommodation. CONCLUSIONS: Overall, the rate of resignation was 41%, and the most frequent timing of resignation was after discharge post-HCT, accounting for approximately half of the resignations (46%). Workplace accommodations increased the rate of return to work from 52% to 76%. IMPLICATIONS FOR CANCER SURVIVORS: Early detection of employment-related concerns and support throughout the treatment process are necessary for patients receiving allo-HCT.

Pharmacokinetically guided, once-daily intravenous busulfan in combination with fludarabine for elderly AML/MDS patients as a conditioning regimen for allogeneic stem cell transplantation.

The efficacy of pharmacokinetically (PK) guided, once-daily administration of busulfan (BU) was evaluated in elderly patients with acute myeloid leukemia/myelodysplastic syndrome (AML/MDS). Twenty-one patients (median age 61) received 30 mg/m2 fludarabine for 6 days and BU for 4 days, starting from 3.2 mg/m2 and subsequently adjusted to the target area under the curve (AUC) of 6000 µmol-min/L. The median AUC of day 1 (AUC1), AUC4, and their average were 4871.3, 6021.0, and 5368.1 µmol-min/L, respectively. Veno-occlusive disease/sinusoidal obstructive syndrome (VOD/SOS) occurred in five patients (24%) but all recovered well. Four patients (20%) had non-infectious pulmonary complications (NIPCs). Patients with high AUC1 had frequent gastrointestinal adverse events, but similar incidence of VOD/SOS and NIPCs. Two-year overall survival (OS), non-relapse mortality (NRM), and relapse rates were 44.4%, 28.6%, and 29.1%, respectively. Patients with high AUC1 had significantly high NRM (57.1% vs. 14.3%, P = 0.04) and inferior OS (14.3% vs. 60.1%, P = 0.002), while patients with high AUC4 had a significantly low relapse rate (8.3% vs. 55.6%, P = 0.02). In conclusion, once-daily BU and a PK-guided dose intensification were beneficial for reducing relapse in elderly patients with AML/MDS. However, caution should be exercised as rapid BU dose elevation may contribute to NRM.

Pre-conditioning intervention in patients with relapsed or refractory acute lymphoblastic leukemia who underwent allogeneic hematopoietic cell transplantation: a KSGCT multicenter retrospective analysis.

The efficacy and clinical significance of pre-conditioning intervention (PCI) before allogeneic hematopoietic cell transplantation (HCT) in patients with acute lymphoblastic leukemia (ALL) not in remission remain inconclusive. The purpose of this multicenter retrospective study was to clarify the clinical significance of PCI before HCT in patients with non-remission ALL. Patients with non-remission ALL who received HCT between 2005 and 2015 at 16 institutions were included. PCI was objectively defined and classified to three groups according to the intensity of PCI (no, intensive, or moderate). The study cohort consisted of 104 patients with a median age of 38 (range 17-68). A significant decrease of blast percentage in the peripheral blood (PB) was confirmed in both PCI groups, suggesting that PCIs were effective to stabilize the disease activity. The group with moderate PCI had higher nucleated cell count in the BM compared to the group with intensive PCI or the group without PCI. The overall survival (OS) rates of groups with intensive and no PCI showed comparable and significantly better compared to the group with moderate PCI (P = 0.009). Multivariate analysis demonstrated that the OS of moderate PCI group was significantly worse compared to that of intensive PCI group (HR = 2.43, 95% CI: 1.32-4.14, P = 0.004), while the OS of intensive PCI group was comparable to that of the group without PCI. These results suggest that the intensity of PCI rather than the response to PCI may contribute to improve the transplant outcome in patients with ALL not in remission.

Newly proposed threshold and validation of white blood cell count at diagnosis for Philadelphia chromosome-positive acute lymphoblastic leukemia: risk assessment of relapse in patients with negative minimal residual disease at transplantation-a report from the Adult Acute Lymphoblastic Leukemia Working Group of the JSTCT.

White blood cell count (WBC) at diagnosis is the conventional prognostic factor in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Nevertheless, little is known about the impact of WBC at diagnosis considering the minimal residual disease (MRD) status at allogeneic hematopoietic cell transplantation (HCT). We evaluated adult patients with Ph+ ALL who achieved negative-MRD and received HCT in first complete remission between 2006 and 2018. The entire cohort was temporally divided into derivation (n = 258) and validation cohorts (n = 366). Using a threshold of 15,000/µL, which was determined by a receiver operating characteristic curve analysis in the derivation cohort, high WBC was associated with an increased risk of hematological relapse in both the derivation cohort (25.3% vs. 11.6% at 7 years, P = 0.004) and the validation cohort (16.2% vs. 8.5% at 3 years, P = 0.025). In multivariate analyses, high WBC was a strong predictor of hematological relapse in the derivation cohort (HR, 2.52, 95%CI 1.32-4.80, P = 0.005) and in the validation cohort (HR, 2.32, 95%CI, 1.18-4.55; P = 0.015). In conclusion, WBC at diagnosis with a new threshold of 15,000/µL should contribute to better risk stratification in patients with negative-MRD at HCT.

Pharmacokinetics of intravenous busulfan as condition for hematopoietic stem cell transplantation: comparison between combinations with cyclophosphamide and fludarabine.

Busulfan (Bu) has been used in combination with fludarabine (Flu; BuFlu) or cyclophosphamide (Cy; BuCy) as conditioning for allogeneic hematopoietic stem cell transplantation (HSCT). This multi-institutional prospective study compared pharmacokinetic (PK) parameters of Bu between BuFlu and BuCy. Plasma Bu concentrations were measured by high-performance liquid chromatography at the first dose of the first and fourth days of intravenous Bu administrations (total of 16 doses of 0.8 mg/kg). Thirty-seven patients were evaluable (BuFlu, N = 18; BuCy, N = 19). The median age was significantly higher in BuFlu. In BuFlu, the median area under the blood concentration-time curve of Bu on the fourth day was 1183 µmol min/L (range 808-1509), which was significantly higher than that on the first day [1095 µmol min/L (range 822-1453), P < 0.01]. In contrast, such differences were not observed in BuCy. Consistently, there was a significant decrease in the clearance of Bu on the fourth day as compared with the first day in BuFlu. These results suggest that the PK of Bu was altered during the co-administration of Flu, which was not the case with Cy. A large-scale study is required to evaluate the significance of the differences in the PK of Bu between the conditionings on HSCT outcomes.

Clinical Benefits of Preconditioning Intervention in Patients with Relapsed or Refractory Acute Myelogenous Leukemia Who Underwent Allogeneic Hematopoietic Cell Transplantation: A Kanto Study of Group for Cell Therapy Multicenter Analysis.

A multicenter retrospective study was conducted to evaluate the clinical significance of preconditioning intervention (PCI) before allogeneic hematopoietic cell transplantation (HCT) in patients with acute myelogenous leukemia (AML) not in remission. The study cohort consisted of 519 patients classified according to the intensity (intensive/moderate) of PCI and their response to PCI. The group treated with PCI had higher blast counts in the peripheral blood (PB) and had a lower overall survival (OS) rate (P < .001) and higher nonrelapse mortality (NRM) rate (P = .035) compared with those without PCI (no PCI group). Approximately 40% of the patients (68 of 236) achieved a good response to PCI (good PCI group), and those patients had lower blast counts in the PB compared with the group with poor response to PCI (poor PCI group). OS in the good PCI group was comparable to that in the no PCI group and significantly better than that in the poor PCI group (hazard ratio, .54; 95% confidence interval, .39 to .77; P < .001). However, OS was significantly lower in patients with intensive/moderate PCI compared with the no PCI group. These results suggest that PCI increases NRM without decreasing the post-transplantation relapse rate, but may be beneficial for patients with lower blast counts in PB irrespective of its intensity.

The sensitivity of the FLT3-ITD detection method is an important consideration when diagnosing acute myeloid leukemia.

Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is a key predictive factor for the prognosis of acute myeloid leukemia (AML). We compared the detection sensitivity of fragment analysis with that of PCR-electrophoresis using MV4-11 (FLT3-ITD) and NKM-1 (FLT3-wild type) cell lines. DNA of these cells was mixed at different ratios and subjected to PCR-electrophoresis or fragment analysis. PCR-electrophoresis was found to have an FLT3-ITD allelic ratio (AR) detection limit of 0.034-0.072. Visual inspection of the PCR-electrophoresis revealed a lower detection sensitivity than that of fragment analysis. Therefore, it is essential to conduct fragment analysis when screening for FLT3-ITD.

Reduced-intensity conditioning is a reasonable alternative for Philadelphia chromosome-positive acute lymphoblastic leukemia among elderly patients who have achieved negative minimal residual disease: a report from the Adult Acute Lymphoblastic Leukemia Working Group of the JSHCT.

Reduced-intensity conditioning (RIC) regimens have been widely used for allogeneic hematopoietic cell transplantation (HCT) in elderly patients. After the emergence of tyrosine kinase inhibitor (TKI), most patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL) now achieve negative results for minimal residual disease (MRD) at HCT. In this study, we evaluated patients aged 50 years or more with Ph-positive ALL who received TKI before HCT, achieved negative-MRD at HCT, and underwent their first allogeneic HCT between 2008 and 2017. In total, 90 and 136 patients who received myeloablative conditioning (MAC) and a RIC regimen, respectively, were included. The median age of patients with MAC and RIC was 54 and 60 years, respectively. Even in multivariate analyses, RIC was not significantly associated with overall mortality (hazard ratio [HR], 1.09; P = 0.724), hematological relapse (HR, 1.97; P = 0.170), or non-relapse mortality (HR, 0.84; P = 0.540). Subgroup analyses suggested that RIC resulted in superior overall survival due to a lower incidence of non-relapse mortality in patients with a poor performance status or a high HCT comorbidity index. In conclusion, RIC is a reasonable option for elderly patients with negative-MRD at HCT.

Outcomes and Prognostic Factors for Patients with Relapsed or Refractory Acute Lymphoblastic Leukemia Who Underwent Allogeneic Hematopoietic Cell Transplantation: A KSGCT Multicenter Analysis.

A multicenter retrospective study was performed to evaluate the prognostic factors in 104 patients with relapsed or refractory acute lymphoblastic leukemia (ALL), who underwent allogeneic hematopoietic cell transplantation (HCT) between 2005 and 2015. The median age was 38 (range, 17 to 68), and the median blast fraction in peripheral blood and bone marrow was 1% (range, 0 to 99%) and 52% (range, 0 to 100%), respectively. With a median follow-up of 47 months (range, 8.3 to 105 months), overall survival (OS), nonrelapse mortality, and relapse mortality at 1 year were 25%, 44%, and 31%, respectively. Multivariate analysis demonstrated independent predictors for poor OS, including nuclear cell count in the bone marrow ≥10 × 104/µL (hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.33 to 3.43; P = .002), elevated lactate dehydrogenase level (HR, 1.66; 95% CI, 1.05 to 2.62; P = .031), and no primary induction failure (HR, 2.05; 95% CI, 1.11 to 3.78; P = .022). A prognostic scoring index was designed based on these survival predictors. At 2 years, OS was 28%, 14%, and 0% for good (score 0 or 1; n = 47), intermediate (score 2; n = 40), and poor (score 3; n = 17), respectively (P < .001). This scoring system may be useful in identifying the patient population for which allogeneic HCT is least beneficial in advanced stages of ALL.

A Prospective, Longitudinal Observation of the Incidence, Treatment, and Survival of Late Acute and Chronic Graft-versus-Host Disease by National Institutes of Health Criteria in a Japanese Cohort.

To prospectively validate the incidence, manifestations, and outcomes of graft-versus-host disease (GVHD) by National Institutes of Health criteria, we recruited 406 hematopoietic stem cell transplantation recipients at 16 transplant centers in Japan from May 2012 to June 2014. The 2-year cumulative incidence of late acute and chronic GVHD was 3.2% (n = 13) and 35.4% (n = 145), with a median onset of 3.6 and 4.7 months after transplant, respectively. The global severity at onset was mild in 30.3%, moderate in 43.5%, and severe in 26.2%. Eighty-two patients were followed up for 2 years, with 79.3% still manifesting GVHD symptoms, and 80.6% (n = 117) of the patients received systemic immunosuppressive treatment (IST), with a 2-year cumulative incidence of IST termination of 33.1%. Severe patients showed a significantly lower rate of IST termination than those with mild and moderate severities (mild, 38.5%; moderate, 40.9%; and severe, 17.2%). The 2-year incidence of nonrelapse mortality (NRM) and relapse was not significantly different according to the severity at onset (NRM: mild [16.6%] versus moderate [8.7%] versus severe [16.1%]; relapse: mild [14.9%] versus moderate [14.7%] versus severe [5.3%]). As a result, 2-year overall survival (OS) and GVHD-specific survival (GSS) were equivalent according to the severity at onset (mild: OS = 81.0%, GSS = 85.7%; moderate: OS = 84.2%, GSS = 92.5%; severe: OS = 83.9%, GSS = 89.2%). Our study helped identify the characteristics of late acute and chronic GVHD in Japanese patients. Further investigation is needed to identify an optimal endpoint for survival prediction.

Allogeneic hematopoietic stem cell transplantation for aplastic anemia with pre-transplant conditioning using fludarabine, reduced-dose cyclophosphamide, and low-dose thymoglobulin: A KSGCT prospective study.

The optimal pre-transplant conditioning for aplastic anemia (AA) remains unclear. We performed a prospective study on allogeneic transplantation from a related or unrelated donor for adult patients with AA. We assessed whether reduced-dose cyclophosphamide (CY) could decrease toxicity while maintaining engraftment, and low-dose thymoglobulin could safely prevent graft-vs-host disease (GVHD). The pre-transplant conditioning regimen consisted of fludarabine 120 mg/m2 , CY 100 mg/kg, and thymoglobulin 2.5 mg/kg with or without 2 Gy of total body irradiation. Twenty-seven patients with a median age of 36 years were analyzed. Sixteen patients received graft from related donors. The stem cell source was bone marrow in 26 patients. All of the patients but one, who died early, achieved neutrophil engraftment at a median of 19 days. Mixed chimerism was observed in six and five patients at days 30 and 90, respectively. Only one patient experienced secondary engraftment failure with complete donor-type chimerism. None of the patients developed severe acute GVHD. The cumulative incidence of chronic GVHD was 37.7% at 1 year. The overall survival rate was 96.3% at 1 year and 3 years. A high EB virus-DNA load was detected in one patient at days 60. No one developed EBV-lymphoproliferative disorder within a year. The results suggest that the conditioning regimen in this study was safe and effective. However, relatively high incidence of chronic GVHD needs further improvement.

Significance of FLT3-tyrosine kinase domain mutation as a prognostic factor for acute myeloid leukemia.

The prognostic significance of FLT3-tyrosine kinase domain (TKD) mutations remains unknown. To investigate the prognostic impact of FLT3-TKD, 676 de novo acute myeloid leukemia (AML), we retrospectively analyzed cases and conducted a review of the literature. Of the 676 de novo AML cases, 34 (5.0%) were FLT3-TKD-positive; both FLT3-TKD and FLT3-ITD were noted in only two cases (0.3%). Although no significant differences in relapse-free survival (RFS) were noted, FLT3-TKD-positive cases showed better prognoses than FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.152). For overall survival (OS), although FLT3-TKD-positive cases showed prognoses similar to those for FLT3-WT cases, their prognoses were significantly better than those of FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.032). Moreover, the 5-year OS for FLT3-TKD-positive cases was 46.1%, indicating that this as an intermediate prognosis group. Although no reports from Asia have indicated a frequency of FLT3-TKD-positive cases > 10%, several reports from Europe and the United States have indicated frequencies > 10%. This suggests the possibility that FLT3-TKD-positive cases are less common in Asia than in Europe and the United States. We anticipate that in the future, the appearance of targeting agents, such as FLT3 inhibitors, will improve the prognosis of FLT3-TKD-positive AML relative to that of FLT3-WT AML.

Prognostic index for patients with relapsed or refractory acute myeloid leukemia who underwent hematopoietic cell transplantation: a KSGCT multicenter analysis.

A multicenter retrospective study was performed to explore a prognostic scoring index in order to identify a population who are least likely to benefit from allogeneic hematopoietic cell transplantation (HCT) in patients with relapsed or refractory acute myeloid leukemia (AML). The cohort included 519 patients with AML, who received HCT between 2005 and 2015 at a status of relapse or primary induction failure. Multivariate analysis demonstrated five independent predictors for OS, including C-reactive protein ≥ 1 mg/dL, peripheral blood blast fraction ≥ 20%, poor-risk karyotype, performance status ≥ 2, and bone marrow unrelated donor as a stem cell source. A prognostic scoring index was explored based on these predictors, and successfully separated the cohort into four groups. At 2 years, OS was 47%, 24%, 8%, and 0% for Good (Score 0, 1: n = 118), Intermediate-1 (Score 2: n = 75), Intermediate-2 (Score 3: n = 39), and Poor (Score 4: n = 24), respectively (P < 0.001). The predicting value of the index was confirmed in a validation cohort. Although a further validation study is warranted, the scoring index may be useful to predict survival and to identify the population with the lowest survival prior to HCT in patients with relapsed or refractory AML.