Unification of hematopoietic stem cell transplantation registries in Japan and establishment of the TRUMP system

HLA Class I Allele Loss and Bone Marrow Transplantation Outcomes in Immune Aplastic Anemia

In patients with immune-mediated acquired aplastic anemia (AA), HLA class I alleles often disappear from the surface of hematopoietic progenitor cells, potentially enabling evasion from cytotoxic T lymphocyte-mediated pathogenesis. Although HLA class I allele loss has been studied in AA patients treated with immunosuppressive therapy (IST), its impact on allogeneic bone marrow transplantation (BMT) has not been thoroughly investigated. The purpose of this study was to evaluate the clinical implications of HLA class I allele loss in patients with acquired AA undergoing allogeneic BMT. The study enrolled acquired AA patients who underwent initial BMT from unrelated donors through the Japan Marrow Donor Program between 1993 and 2011. The presence of HLA class I allele loss due to loss of heterozygosity (HLA-LOH) was assessed using pretransplantation blood DNA and correlated with clinical data obtained from the Japanese Transplant Registry Unified Management Program. A total of 432 patients with acquired AA were included in the study, and HLA-LOH was detected in 20 of the 178 patients (11%) available for analysis. Patients with HLA-LOH typically presented with more severe AA at diagnosis (P = .017) and underwent BMT earlier (P < .0001) compared to those without HLA-LOH. They also showed a slight but significant recovery in platelet count from the time of diagnosis to BMT (P = .00085). However, HLA-LOH status had no significant effect on survival, engraftment, graft failure, chimerism status, graft-versus-host disease, or other complications following BMT, even when the 20 HLA-LOH+ patients were compared with the 40 propensity score-matched HLA-LOH- patients. Nevertheless, patients lacking HLA-A*02:06 or HLA-B*40:02, the alleles most frequently lost and associated with a better IST response, showed higher survival rates compared to those lacking other alleles, with estimated 5-year overall survival (OS) rates of 100% and 44%, respectively (P = .0042). In addition, in a specific subset of HLA-LOH- patients showing clinical features similar to HLA-LOH+ patients, the HLA-A*02:06 and HLA-B*40:02 allele genotypes correlated with better survival rates compared with other allele genotypes, with estimated 5-year OS rates of 100% and 43%, respectively (P = .0096). However, this genotype correlation did not extend to all patients, suggesting that immunopathogenic mechanisms linked to the loss of certain HLA alleles, rather than the HLA genotypes themselves, influence survival outcomes. The survival benefit associated with the loss of these two alleles was confirmed in a multivariable Cox regression model. The observed correlations between HLA loss and the pretransplantation clinical manifestations and between loss of specific HLA class I alleles and survival outcomes in AA patients may improve patient selection for unrelated BMT and facilitate further investigations into the immune pathophysiology of the disease.

Low- versus standard-dose post-transplant cyclophosphamide as GVHD prophylaxis for haploidentical transplantation

Haploidentical haematopoietic cell transplantation (haplo-HCT) using post-transplant cyclophosphamide (PTCY) as graft-versus-host disease (GVHD) prophylaxis is the standard of care for various haematological malignancies. The original PTCY dose after haplo-HCT was 100 mg/kg, but no dose-finding studies have been performed to identify the optimal dose. We performed a retrospective analysis to compare standard-dose PTCY (100 mg/kg) with reduced-dose PTCY (80 mg/kg): 969 in the standard-dose group and 538 in the reduced-dose group. As there was a significant difference between the two groups regarding patient and transplant characteristics, we performed propensity score (PS) matching. After PS matching, 425 patients in each group were included. The probabilities of 2-year OS were 55.9% in the standard-dose group and 47.0% in the reduced-dose group (p = 0.36). The cumulative incidences of 2-year non-relapse mortality were 21.3% in the standard-dose group and 20.5% in the reduced-dose group (p = 0.55). There was no significant difference in the incidence of acute (grade II-IV 29.2% [95% CI, 24.9-33.6] vs. 25.3% [95% CI, 21.3-29.6]; grade III-IV 7.3% [95% CI, 5.1-10.0] vs. 6.6% [95% CI, 4.5-9.3]) or chronic GVHD. In conclusion, reduced- and standard-dose PTCY were comparable in terms of major clinical outcomes.

Comparison of fludarabine-based conditioning regimens in adult cord blood transplantation for myeloid malignancy: A retrospective, registry-based study

Fludarabine/busulfan and fludarabine/melphalan are viable options as conditioning regimens. However, the optimal fludarabine-based conditioning in cord blood transplantation (CBT) remains unclear. Therefore, this retrospective, registry-based study aimed to analyze the impact of five fludarabine-containing conditioning regimens on 1395 adult patients (median age, 61 years) with acute myeloid leukemia, myelodysplastic syndrome, and chronic myeloid leukemia who underwent their first CBT. Treatment outcomes of fludarabine combined with melphalan (100-140 mg/m2 ) and low-dose total body irradiation (TBI; FM140T); melphalan (80-99 mg/m2 ) and TBI (FM80T); busulfan (12.8 mg/kg) and melphalan (FB4M); busulfan (12.8 mg/kg) and TBI (FB4T); and busulfan (6.4 mg/kg) and TBI (FB2T) were compared. The 3-year survival rate was 67%, 53%, 44%, 36%, and 39%, respectively (p < .0001). The FM140T survival rate was the most favorable after adjusting for confounders, and the hazard ratios (vs. FM140T) for overall mortality were as follows: FM80T, 1.6 (95% confidence interval [CI], 1.2-2.2); FB4M, 2.1 (95% CI, 1.6-2.8); FB4T, 2.7 (95% CI, 2.0-3.7); and FB2T, 2.2 (95% CI, 1.6-3.1). The better survival observed with FM140T, regardless of the disease, disease risk, age, or transplant year, was attributed to the lower relapse rate and lower non-relapse mortality (NRM) associated with fewer infectious deaths. Conversely, FB4T was associated with a higher relapse rate and higher NRM. The findings indicate that the outcomes of CBT in myeloid malignancies were highly dependent on both the alkylating agent and its dose in combination with fludarabine. Therefore, compared with fludarabine/busulfan-based conditioning, FM140T may be the preferred regimen.

Improved Long-Term Net Survival after Allogeneic Hematopoietic Cell Transplantation in Patients with Hematologic Malignancies over Two Decades

Allogeneic (allo-) hematopoietic cell transplantation (HCT) has evolved as a curative therapy for hematologic malignancies and diseases, with practice changes over the past 2 decades. This study aimed to evaluate the change in 5-year net survival (NS) of allo-HCT recipients in a population-based cohort over the past 2 decades, which allows the estimation of a more HCT-specific long-term survival rate by considering background mortality changes. This study included 42,064 patients with hematologic malignancies who underwent their first allo-HCT in Japan between 2000 and 2018 and were reported to the Transplant Registry Unified Management Program. We compared the 5-year NS after allo-HCT in 4 consecutive HCT periods (2000 to 2004, 2005 to 2008, 2009 to 2012, and 2013 to 2018). The 5-year NS of the latest period was estimated using the period analysis method. Adjusted excess hazard ratios (EHRs) for 5-year NS over the HCT period were analyzed using an EHR model. In addition to the analysis of all hematologic malignancies, adjusted 5-year NS for each major hematologic malignancy, including acute myelogenous leukemia, acute lymphoblastic leukemia (ALL), myelodysplastic syndrome, adult T cell leukemia/lymphoma, chronic myeloid leukemia (CML), and malignant lymphoma, was analyzed. The probability of adjusted 5-year NS after HCT improved significantly over time: 35% in 2000 to 2004, 39% in 2005 to 2008, 45% in 2009 to 2012, and 49% in 2013 to 2018. The adjusted EHRs were .90 (95% confidence interval [CI], .86 to .93) in the 2005 to 2008 period, .77 (95% CI, .74 to .80) in the 2009 to 2012 period, and .65 (95% CI, .63 to .68) in the 2013 to 2018 period, with the 2000 to 2004 period as the reference. The 5-year NS improved among all hematologic malignancies, with a significant improvement in CML and ALL. The changes in 5-year NS from the 2000 to 2004 period to the 2013 to 2018 period ranged from 46% to 66% in CML and from 41% to 59% in ALL. In addition to the large improvement of 1-year NS, smaller but continued improvement in NS between 1 and 5 years after transplantation was observed. NS at 5 years conditional on being alive at 1 year increased from 64% in 2000 to 2004 to 73% in 2013 to 2018. Even after subtracting the background mortality in the general population, we found a significant improvement in long-term allo-HCT-specific survival rates for patients with hematologic malignancies over the past 2 decades in Japan.

Adverse impact of delay of platelet recovery after autologous hematopoietic cell transplantation for aggressive non-Hodgkin lymphoma and multiple myeloma

BACKGROUND AIMS

The prognostic impact of platelet recovery after autologous hematopoietic cell transplantation (AHCT) on clinical outcomes remains to be elucidated. We aimed to clarify the impact of platelet recovery on clinical outcomes, risk factors of delayed platelet recovery and the necessary dose of CD34+ cells for prompt platelet recovery in each patient.

METHODS

Using a nationwide Japanese registry database, we retrospectively analyzed clinical outcomes of 5222 patients with aggressive non-Hodgkin lymphoma (NHL) or multiple myeloma (MM).

RESULTS

At a landmark of 28 days after AHCT, a delay of platelet recovery was observed in 1102 patients (21.1%). Prompt platelet recovery was significantly associated with superior overall survival (hazard ratio [HR] 0.32, P < 0.001), progression-free survival (HR 0.48, P < 0.001) and decreased risks of disease progression (HR 0.66, P < 0.001) and non-relapse/non-progression mortality (HR 0.19, P < 0.001). The adverse impacts of a delay of platelet recovery seemed to be more apparent in NHL. In addition to the dose of CD34+ cells/kg, disease status, performance status and the hematopoietic cell transplant-specific comorbidity index in both diseases were associated with platelet recovery. We then stratified the patients into three risk groups according to these factors. For the purpose of achieving 70% platelet recovery by 28 days in NHL, the low-, intermediate- and high-risk groups needed more than 2.0, 3.0 and 4.0 × 106 CD34+ cells/kg, respectively. In MM, the low-risk group needed approximately 1.5 × 106 CD34+ cells/kg, whereas the intermediate- and high-risk groups required 2.0 and 2.5 × 106 CD34+ cells/kg to achieve about 80% platelet recovery by 28 days.

CONCLUSIONS

A delay of platelet recovery after AHCT was associated with inferior survival outcomes.

Outcomes in human T-cell leukemia virus type I carriers after hematopoietic stem cell transplantation for diseases other than adult T cell leukemia/lymphoma: a Japanese national survey

Background

Human T-cell leukemia virus type I (HTLV-1) is a retrovirus known to cause adult T-cell leukemia/lymphoma (ATL). There are few reports on hematopoietic stem cell transplantation (HSCT) for HTLV-1 carriers with diseases other than ATL.

Methods

A total of 25,839 patients (24,399 adults and 1440 children) with pre-transplant HTLV-1 serostatus information recorded in the Japanese National Survey Database who had undergone their first HSCT were analyzed. We investigated the overall survival (OS), transplant-related mortality (TRM), and disease-related mortality (DRM) after HSCT in relation to HTLV-1 serologic status.

Findings

Three hundred and forty-eight patients were HTLV-1 antibody carriers. The number of HTLV-1 carriers and noncarriers among adult patients who received allogeneic HSCT (allo-HSCT) or autologous HSCT (auto-HSCT) was 237/15,777 and 95/8920, respectively, and was 16/1424 among pediatric patients who received allo-HSCT. No pediatric HTLV-1 carrier recipients undergoing auto-HSCT were identified. There were no significant differences between HTLV-1 carriers and non-carriers regarding stem cell source, disease risk, or HCT-CI score prior to allo-HSCT. Multivariate analysis of OS (P = 0.020) and TRM (P = 0.017) in adult patients showed that HTLV-1 positive status was a significant prognostic factor. In children, TRM was significantly higher (P = 0.019), but OS was not significantly different. In adult patients who underwent auto-HSCT, HTLV-1 positive status was not a significant prognostic factor. In adult allo-HSCT patients, cytomegalovirus reactivation was significantly more common in HTLV-1 carriers (P = 0.001).

Interpretation

HTLV-1 antibody positivity was shown to have a poor prognosis in OS and TRM after allo-HSCT in adult patients and in TRM after allo-HSCT in pediatric patients.

Funding

This work was supported in part by the practical research programs of the Japan Agency for Medical Research and Development (AMED) under grant number 17ck0106342h0001.

A double encryption protection algorithm for stem cell bank privacy data based on improved AES and chaotic encryption technology

The unique infinite self-renewal ability and multidirectional differentiation potential of stem cells provide a strong support for the clinical treatment. In light of the growing demands for stem cell storage, how to ensure personal privacy security and comply with strict ethical supervision requirements is particularly important. In order to solve the problem of low security of traditional encryption algorithm, we proposed a double encryption protection (DEP) algorithm for stem cell bank privacy data based on improved AES and chaotic encryption technology. Firstly, we presented the hash value key decomposition algorithm, through the hash value dynamic coding, cyclic shift, conversion calculation to get the key of each subsystem in the built algorithm. Secondly, DEP algorithm for privacy data is realized with two level of encryption. The first level of encryption protection algorithm used AES as the main framework, adding dynamic coding and byte filling based on DNA coding, and carries out dynamic shift of rows and simplified mixing of columns. The second level of encryption protection algorithm conducted random encoding, operation, diffusion and decoding based on the results of our proposed sequence conversion algorithm. Finally, we raised two evaluation indexes, the number of characters change rate (NCCR) and the unified average change intensity of text (UACIT) to measure the sensitivity of encryption algorithms to changes in plain information. The experimental results of using DEP shown that the average values of histogram variance, information entropy, NCCR and UACIT are116.7883, 7.6688, 32.52% and 99.67%, respectively. DEP algorithm has a large key space, high key sensitivity, and enables dynamic encryption of private data in stem cell bank. The encryption scheme provided in this study ensures the security of the private information of stem cell bank in private cloud environment, and also provides a new method for the encryption of similar high confidentiality data.

Risk factors for fatal cardiac complications after allogeneic hematopoietic cell transplantation: Japanese Society for Transplantation and Cellular Therapy transplant complications working group

Fatal cardiac complications can occur from the early to late phases after hematopoietic cell transplantation (HCT). Herein, the Japanese transplant registry database was used to retrospectively analyze health records of 33,791 allogeneic HCT recipients to elucidate the pathogenesis and risk factors involved. Overall, 527 patients died of cardiac complications at a median of 130 (range 0-3924) days after HCT. The cumulative incidence of fatal cardiac complications was 1.2% (95% confidence interval [CI]: 1.0-1.3) and 1.6% (95% CI: 1.5-1.8) at 1 and 5 years after HCT, respectively. Fatal cardiovascular events were significantly associated with an HCT-specific comorbidity index (HCT-CI) score of ≥1 specific to the three cardiovascular items, lower performance status, conditioning regimen cyclophosphamide dose of >120 mg/kg, and female sex. Cardiovascular death risk within 60 days after HCT was associated with the type of conditioning regimen, presence of bacterial or fungal infections at HCT, and number of blood transfusions. Contrastingly, late cardiovascular death beyond 1 year after HCT was associated with female sex and older age. Lower performance status and positive cardiovascular disease-related HCT-CI were risk factors for cardiac complications in all phases after HCT. Systematic follow-up may be necessary according to the patients' risk factors and conditions.

A convolutional neural network-based model that predicts acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Forecasting acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT) is highly challenging with conventional statistical techniques due to complex parameters and their interactions. The primary object of this study was to establish a convolutional neural network (CNN)-based prediction model for aGVHD.

METHOD

We analyzed adult patients who underwent allogeneic HSCT between 2008 and 2018, using the Japanese nationwide registry database. The CNN algorithm, equipped with a natural language processing technique and an interpretable explanation algorithm, was applied to develop and validate prediction models.

RESULTS

Here, we evaluate 18,763 patients between 16 and 80 years of age (median, 50 years). In total, grade II-IV and grade III-IV aGVHD is observed among 42.0% and 15.6%. The CNN-based model eventually allows us to calculate a prediction score of aGVHD for an individual case, which is validated to distinguish the high-risk group of aGVHD in the test cohort: cumulative incidence of grade III-IV aGVHD at Day 100 after HSCT is 28.8% for patients assigned to a high-risk group by the CNN model, compared to 8.4% among low-risk patients (hazard ratio, 4.02; 95% confidence interval, 2.70-5.97; p < 0.01), suggesting high generalizability. Furthermore, our CNN-based model succeeds in visualizing the learning process. Moreover, contributions of pre-transplant parameters other than HLA information to the risk of aGVHD are determined.

CONCLUSIONS

Our results suggest that CNN-based prediction provides a faithful prediction model for aGVHD, and can serve as a valuable tool for decision-making in clinical practice.

Clinical characteristics and risk factors of pneumococcal diseases in recipients of allogeneic hematopoietic stem cell transplants in the late phase: A retrospective registry study

Pneumococcal diseases are one of the most important infectious complications in the late period following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The importance of long-term follow-up care is increasing, as the number of long-term survivors following allo-HSCT increases, but there has been a dearth of research specifically focusing on pneumococcal diseases during the late post-transplant period (day >100). Using a transplant registry database between January 1, 2001 and December 31, 2011, we aimed to assess the clinical spectrum and risk factors for pneumococcal diseases in the late post-transplant period. Among the 22,514 recipients who received allo-HSCT over an 11-year period and could be followed for ≥100 days, 43 patients developed 49 episodes of pneumococcal diseases. Six of the 43 patients died from pneumococcal diseases, and four of these six patients died within a week, despite having undergone allo-HSCT two or more years ago. A history of chronic graft-versus-host disease (odds ratio [OR], 2.31; 95% confidence interval [CI], 1.15-4.66; P = 0.02), viral infection (OR, 3.38; 95% CI, 1.70-6.72; P < 0.01), and complete remission of the underlying disease at the time of transplantation (OR, 2.38; 95%CI, 1.10-5.14; P = 0.03) were identified as risk factors. Given the risk of sudden death and the high mortality rate, attention should be paid to pneumococcal diseases in providing long-term follow-up care, even several years after allo-HSCT.

Adverse effect of donor-specific anti-human leukocyte antigen (HLA) antibodies directed at HLA-DP/-DQ on engraftment in cord blood transplantation

BACKGROUND AIMS

While donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) in the recipient before transplantation are associated with graft failure in cord-blood transplantation (CBT), effects of DSAs other than against HLA-A, -B or -DRB1 on transplantation outcomes remained poorly understood.

METHODS

We retrospectively analyzed 567 single-unit CBT recipients to evaluate impact of DSAs against HLA-DP and -DQ on CBT outcomes.

RESULTS

Among 143 recipients (25.2%) who had anti-HLA antibodies, nine harbored DSAs against HLA-DP or -DQ. DSAs against HLA-DP or -DQ were associated with a significantly lower neutrophil engraftment rate (55.6% versus 91.8%, P = 0.032) and with a marginally lower platelet engraftment rate (46.7% versus 75.3%, P = 0.128) at day 100 after transplantation, compared with patients without anti-HLA antibodies. Time to neutrophil and platelet engraftment in patients with DSAs for HLA-DP or -DQ was significantly longer than that in patients without anti-HLA antibodies (median, 25 versus 21 days, P = 0.002 in neutrophil; median 61 versus 46 days, P = 0.014 in platelet). Cumulative incidence of bacterial infection at day 100 was significantly greater (88.9% versus 57.1%, P = 0.024), and re-transplant-free survival was marginally lower (55.6% versus 76.8%, P = 0.132) in patients with DSAs against HLA-DP or -DQ, compared with those without anti-HLA antibodies. These findings suggest that DSAs against HLA-DP or -DQ lead to unfavorable engraftment, which may increase risk of bacterial infection, and reduce survival soon after CBT.

CONCLUSIONS

Our results suggest the importance of evaluating DSAs against HLA-DP and -DQ in recipients before selecting CB units.

Allogeneic transplantation of bone marrow versus peripheral blood stem cells from HLA-identical relatives in patients with myelodysplastic syndromes and oligoblastic acute myeloid leukemia: a propensity score analysis of a nationwide database

Bone marrow (BM) and granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (PBSC) are used as grafts from HLA-identical-related donors for adults with myelodysplastic syndrome (MDS). To assess the impact of graft sources on post-transplant outcomes in MDS patients, we conducted a retrospective analysis of a nationwide database. A total of 247 and 280 patients underwent transplantation with BM and PBSC, respectively. The inverse probability of treatment weighting (IPTW) methods revealed that overall survival (OS) was comparable between BM and PBSC (P = .129), but PBSC transplantation was associated with worse graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS) (hazard rate [HR], 1.24; 95% confidence intervals [CIs], 1.00-1.53; P = 0.049) and chronic GVHD-free and relapse-free survival (CRFS) (HR, 1.29; 95% CIs, 1.13-1.73; P = 0.002) than BM transplantation. In the propensity score matched cohort (BM, n = 216; PBSC, n = 216), no significant differences were observed in OS and relapse; 3-year OS rates were 64.7% and 60.0% (P = 0.107), while 3-year relapse rates were 27.1% and 23.5% (P = 0.255) in BM and PBSC, respectively. Three-year GRFS rates (36.6% vs. 29.2%; P = 0.006), CRFS rate (37.7% vs. 32.5%; P = 0.003), and non-relapse mortality rates (13.9% vs. 21.1%; P = 0.020) were better in BM than in PBSC. The present study showed that BM transplantation provides a comparable survival benefit with PBSC transplantation and did not identify an enhanced graft-versus-MDS effect to reduce the incidence of relapse in PBSC transplantation.

Advantages of Higher Busulfan Dose Intensity in Fludarabine-Combined Conditioning for Patients with Acute Myeloid Leukemia Undergoing Cord Blood Transplantation

The alkylating agent busulfan is commonly used as conditioning in allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia (AML). However, a consensus has not yet been reached regarding the optimal busulfan dose in cord blood transplantation (CBT). Therefore, we conducted this large nationwide cohort study to retrospectively analyze the outcomes of CBT in patients with AML receiving busulfan at intermediate (6.4 mg/kg i.v.; BU2) or higher (12.8 mg/kg i.v.; BU4) doses within a fludarabine/i.v. busulfan (FLU/BU) regimen. Among 475 patients who underwent their first CBT following FLU/BU conditioning between 2007 and 2018, 162 received BU2 and 313 received BU4. Multivariate analysis identified BU4 as a significant factor for longer disease-free survival (hazard ratio [HR], .85; 95% confidence interval [CI], .75 to .97; P = .014) and a lower relapse rate (HR, .84; 95% CI, .72 to .98; P = .030). No significant differences were observed in non-relapse mortality between BU4 and BU2 (HR, 1.05; 95% CI, .88-1.26; P = .57). Subgroup analyses showed that BU4 provided significant benefits for patients who underwent transplantation while not in complete remission (CR) and those age <60 years. Our present results suggest that higher busulfan doses are preferable in patients undergoing CBT, particularly those not in CR and younger patients.

Adult patients with Ph+ ALL benefit from conditioning regimen of medium-dose VP16 plus CY/TBI

The medium-dose etoposide (VP16) added on cyclophosphamide (CY)/total body irradiation (TBI) is one of the intensified myeloablative conditioning regimens used in allogenic hematopoietic stem cell transplantation (allo-HSCT) for acute lymphoblastic leukemia (ALL). However, the patient subgroups who can actually benefit from VP16/CY/TBI compared to CY/TBI have not been precisely defined. Therefore, we conducted a multi-center retrospective study using the Japanese nationwide registry database to elucidate the efficacy of VP16/CY/TBI on post-transplant prognosis. Biological and clinical distinct subtypes (i.e., Philadelphia chromosome-positive (Ph+) and -negative (Ph-) ALL) were evaluated separately, which included 820 Ph+ and 1463 patients with Ph- ALL, respectively. Compared with the CY/TBI group, the VP16/CY/TBI group showed superior progression-free survival (PFS) in patients with Ph+ ALL (65% vs. 57% at 3 years after HSCT; adjusted hazard ratio (HR), 0.73; 95% confidence interval (CI), 0.55-0.98; p = 0.03), along with significantly reduced incidence of relapse (adjusted HR, 0.58; 95% CI, 0.37-0.90; p = 0.02) without the increase of non-relapse mortality (NRM). By contrast, in patients with Ph- ALL, VP16/CY/TBI did not improve PFS nor incidence of relapse; addition of VP16 reduced relapse (HR, 0.65; p = 0.06) in patients with Ph- ALL transplanted at CR1, while improved PFS was not observed (HR, 0.90; p = 0.52) due to increased NRM. This study demonstrated that VP16/CY/TBI is a more effective and well-tolerated regimen in comparison with CY/TBI in patients with myeloablative allo-HSCT for adult Ph+ ALL. Our findings can provide a novel algorithm for conditioning regimen selection in patients with adult ALL.

Prognostic impact of complex karyotype on post-transplant outcomes of myelofibrosis

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.

Comparable survival outcomes with haploidentical stem cell transplantation and unrelated bone marrow transplantation

We retrospectively compared outcomes of unrelated donor bone marrow transplant (UBMT) and HLA-haploidentical peripheral blood stem cell transplantation using post-transplant cyclophosphamide (PTCy-haploPBSCT) using the Japanese registry data. Recipients of first HCT for acute leukemia and myelodysplastic syndromes between 2012 and 2015 were included. The analyzed subjects comprised UBMT recipients with 8/8 matched HLA alleles (n = 1470), 7/8 matched alleles (n = 859), 6/8 matched alleles (n = 186), and recipients of PTCy-haploPBSCT (n = 133). In multivariate analyses with 8/8 matched UBMT as the reference, PTCy-haploPBSCT showed similar overall mortality, decreased risk of non-relapse mortality (NRM), increased risk of relapse, and decreased risk of grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD. Adjusted probabilities for 8/8 matched UBMT, PTCy-haploPBSCT, and 7/8 and 6/8 matched UBMT groups at 2 years post-transplant were 61%, 60%, 58%, and 52% for overall survival, 23%, 28%, 21%, and 19% for relapse, and 20%, 7%, 24%, and 33% for NRM. PTCy-haploPBSCT was associated with remarkably low NRM, contributing to survival outcomes that were comparable to 8/8 matched UBMT. The higher relapse rate in the PTCy-haploPBSCT group might be associated with the higher proportion of high-risk patients. PTCy-haploPBSCT may be a viable alternative when HLA-matched related donors are not available.

Improvements in allogeneic hematopoietic cell transplantation outcomes for adults with ALL over the past 3 decades

Allogeneic hematopoietic cell transplantation (allo-HCT) is a promising treatment for adult acute lymphoblastic leukemia (ALL), an intractable hematological malignancy. The trends in allo-HCT outcomes over the past 30 years were examined to verify the efficacy of evolving treatment methods and to identify further challenges. We analyzed data from a registry database that included 8467 adult ALL patients who underwent their first allo-HCT between 1990 and 2019. The period was divided into three 10-year intervals for analysis. Five-year overall survival improved from 48.2% to 70.2% in the first complete remission (CR1), from 25.6% to 44.1% in subsequent CR, and from 10.0% to 22.7% in non-CR. Nonrelapse mortality improved over the 3 decades in each disease stage. However, the relapse rate only improved in CR1 every decade (26.3% to 15.9% in CR1, 33.4% to 32.8% in subsequent CR, and 53.6% to 54.8% in non-CR). Although there were continual improvements in adjusted survival for Philadelphia chromosome (Ph)-positive patients, the improvement was inadequate for Ph⁻ patients with t(4;11), t(8;14), t(14;18), or hypodiploidy. Allo-HCT outcomes for adults with ALL have improved over the past 30 years. Improved outcomes in the future will require more effective prevention of relapse in patients with ALL not in CR1 and in those with high-risk chromosomal abnormalities.

Impact of KIR-ligand mismatch on pediatric T-cell acute lymphoblastic leukemia in unrelated cord blood transplantation

BACKGROUND

Currently, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered to be indicated for children and adolescents with high-risk or relapsed T-cell acute lymphoblastic leukemia (T-ALL); however, the outcomes are unsatisfactory. Killer cell immunoglobulin-like receptors (KIRs) are the main receptors on natural killer (NK) cells that play an important role in the graft-versus-leukemia effect after allo-HSCT. In allo-HSCT, when the recipient lacks a donor KIR-ligand (KIR-ligand mismatch in the graft-versus-host [GVH] direction), donor NK cells will be activated against recipient cells. KIR-ligand mismatch in the GVH direction improves outcomes after unrelated cord blood transplantation (UCBT) with acute myeloid leukemia, but the effect in T-ALL is unclear.

OBJECTIVE

We evaluated the impact of KIR-ligand mismatch in the GVH direction on the transplant outcomes of children and adolescents with T-ALL who received UCBT.

STUDY DESIGN

We conducted a retrospective study using a nationwide registry of the Japanese Society for Transplantation and Cellular Therapy. Patients diagnosed with T-ALL, aged 0-19 years, and underwent first UCBT between 1999 and 2017 were included.

RESULTS

A total of 91 patients were included in this study. In all, 23 (25.3%) percent of patients had KIR-ligand mismatch in the GVH direction. The 5-year leukemia-free survival (LFS) and overall survival (OS) rates after UCBT were 65.8% and 69.6%, respectively. In a multivariate analysis, KIR-ligand mismatch in the GVH direction was associated with a significant reduction in the relapse rate (hazard ratio [HR], 0.19; P = 0.002), resulting in better LFS (HR, 0.18; P = 0.010) and OS (HR, 0.26; P = 0.048) without increasing non-relapse mortality (NRM; HR, 1.90; P = 0.264). The cumulative incidence of GVH disease (GVHD) did not differ between patients with and without KIR-ligand mismatch (grade II-IV acute GVHD, 39.1% versus 36.8%, P = 0.648, grade III-IV acute GVHD, 13.0% versus 11.8%, P = 0.857, and chronic GVHD, 26.1% versus 22.9%, P = 0.736, respectively). Furthermore, acute and chronic GVHD were not associated with good patient outcomes. Notably, no relapse was observed in patients who received KIR-ligand mismatched UCBT in complete remission.

CONCLUSION

KIR-ligand mismatch in the GVH direction improved LFS and decreased relapse rates without increasing NRM in children and adolescents with T-ALL who received UCBT, which was not mediated by GVHD.

Registry data analysis of hematopoietic stem cell transplantation on systemic chronic active Epstein-Barr virus infection patients in Japan

The effects of allogeneic hematopoietic stem cell transplantation (allo-HSCT) on systemic chronic active Epstein-Barr virus infection (sCAEBV) are yet to be analyzed in a large number of patients. Using the Japanese registry database, Transplant Registry Unification Management Program, we investigated the outcomes of 102 sCAEBV patients who underwent allo-HSCT. The median age at HSCT was 21 years, and the three-year overall survival (3-year OS) rate was 72.5%. Of the 90 patients whose viral load after allo-HSCT was evaluated, 56 (62.2%) achieved a virological complete response, defined by the complete resolution of disease activity with a significant decrease in EBV-DNA in peripheral blood. The multivariate Cox proportional hazard model indicated that advanced age, in adolescents and young adults (AYA) (age, 15-39) and adults (age, ≥40 years) was a risk factor of poor OS. The hazard ratios (HRs) of the AYA and adult groups were 10.87 (95% confidence interval [CI]: 1.98-59.56, p = .006) and 15.93 (95% CI: 2.45-103.8, p = .004), respectively. Disease activity (HR 5.74), elevated soluble IL-2 receptor (sIL-2R) (≥ median, 691 U/mL) at HSCT (HR 6.93), and conditioning without radiotherapy (HR 3.53) were also independently associated with poor survival. Notably, 79% of radiotherapy doses were less than 6 Gy. Regardless of the presence of hemophagocytic lymphohistiocytosis, the group with a high sIL-2R level (≥2000 U/mL) showed a poorer prognosis. Although allo-HSCT is the only curative therapy for sCAEBV, treatment strategies need to be improved for high-risk patients, especially those with high levels of sIL-2R.

Effect of multiple HLA-locus mismatches on outcomes after single cord blood transplantation

BACKGROUND

Effect of single or multiple mismatches at each HLA locus on outcomes after cord blood transplantation (CBT) is controversial.

OBJECTIVE

We analyzed the effects of single or multiple HLA-locus mismatches on the outcomes after single CBT using a Japanese registry data from the Japan Society for Hematopoietic Cell Transplantation (JSHCT).

STUDY DESIGN

Patients with acute leukemia and myelodysplastic syndromes, aged 16 years or older, who underwent their first CBT between 2003 and 2017 (n = 4,074) were included. The effect of the number of HLA-locus mismatches (0, 1, and 2, for the HLA-A, -B, -C, and -DRB1 loci) on outcomes was analyzed after adjusting for other significant variables.

RESULTS

The median age of the patients was 54 years. Median total nucleated and CD34 cell doses were 2.6 × 10⁷/kg and 0.8 × 10⁵/kg, respectively. The number of CBTs with single or double mismatches were 2,099 and 292 for HLA-A locus, 2,699 and 341 for HLA-B locus, 2,555 and 609 for HLA-C locus, and 2,593 and 571 for HLA-DRB1 locus, respectively. Single and double HLA-DRB1 mismatches were associated with a higher risk of grade II-IV acute graft-versus-host disease (GVHD, single: HR 1.29, P<0.001, double: HR 1.49, P<0.001, trend-P: P<0.001). Single and double mismatches at HLA-DRB1 as well as single mismatches at HLA-A and HLA-B were also associated with grade III-IV acute GVHD. Single and double HLA-B mismatches and double HLA-DRB1 mismatches were associated with a high risk of non-relapse mortality. On the other hand, double mismatches at HLA-A or HLA-DRB1 and single mismatches at HLA-B were associated with a lower risk of relapse.

CONCLUSION

HLA-DRB1 double mismatch was associated with high risks of grade II-IV and III-IV acute GVHD and non-relapse mortality but lower risk of relapse. Not only the locus mismatch but also the number of mismatches may be considered in cord blood unit selection.

Ideal body weight is useful for predicting neutrophil engraftment and platelet recovery for overweight and obese recipients in single-unit cord blood transplantation

BACKGROUND

Since cord blood (CB) units are usually selected based on the cell dose /kg, overweight (25 kg/m² ≤ body mass index (BMI) < 30 kg/m²) and obese (30 kg/m² ≤ BMI) recipients tend to have difficulty in getting appropriate CB units. In general, actual body weight (ABW) is used for CB unit selection. However, ideal body weight (IBW) has been reported to be more closely correlated with successful engraftment after autologous, allogeneic bone marrow, and peripheral blood stem cell transplantation than ABW.

OBJECTIVES

We conducted this analysis to clarify the threshold of CD34⁺ cell doses based on ideal body weight (CD34^IBW) and to compare the outcomes among the groups stratified by the threshold according to actual body weight (CD34^ABW) and CD34^IBW for overweight and obese recipients in cord blood transplantation (CBT).

STUDY DESIGN

We retrospectively analyzed 650 overweight and obese recipients who received single-unit CBT. To focus on the recipients who received a low CD34⁺ cell dose /kg, those who received 1.5×10⁵ CD34⁺ cells /ABW or more were excluded. Using a cut-off of 0.8×10⁵ CD34⁺ cells/kg, we compared the outcomes in 3 groups with low CD34^ABW and low CD34^IBW (CD34^Low/Low), low CD34^ABW but high CD34^IBW (CD34^Low/High), and high CD34^ABW and high CD34^IBW (CD34^High/High).

RESULTS

Hematopoietic recoveries were significantly delayed in the CD34^Low/Low group compared with those in the CD34^Low/High group (hazard ratio (HR) 0.67 for neutrophil, P < 0.001; HR 0.72 for platelet, P = 0.014), while those were comparable in the CD34^Low/High and CD34^High/High groups (HR 1.22 for neutrophil, P = 0.16; HR 1.29 for platelet, P = 0.088). Moreover, the CD34^Low/High group demonstrated longer overall survival than the CD34^Low/Low group (HR 1.48, P = 0.011) and comparable survival to the CD34^High/High group (HR 0.93, P = 0.68).

CONCLUSIONS

This finding may address the lack of availability of CB units for some overweight and obese recipients for whom suitable donors are unavailable. Further investigations are warranted to evaluate the appropriateness of ABW and IBW.

Improved outcomes of single-unit cord blood transplantation for acute myeloid leukemia by killer immunoglobulin-like receptor 2DL1-ligand mismatch

The impact of the killer immunoglobulin-like receptor (KIR)-ligand mismatch between donor and recipient in hematopoietic stem cell transplantation is controversial. Recently, it has been suggested that their effect on cord blood transplantation (CBT) differs among types of mismatched KIR-ligand and graft-versus-host disease (GVHD) prophylaxis. To investigate their role in acute myeloid leukemia (AML), mismatch of KIR2DL1, KIR3DL1, and KIR3DL2-ligand (HLA-C2, Bw4, and A3/11) were retrospectively assessed in patients undergoing CBT with GVHD prophylaxis comprising a calcineurin inhibitor plus methotrexate (CNI/MTX) or mycophenolate mofetil (CNI/MMF). In patients who received CNI/MTX, a favorable effect of KIR-ligand mismatch on relapse was noted in HLA-C2 mismatched cases (24.8% at 3 years post-CBT [no HLA-C2 mismatch, n = 1602] vs. 15.4% [HLA-C2 mismatch, n = 161], P = 0.0116). In this group, overall survival (OS) was also superior (68.2%, P = 0.0083) compared to the other group (55.0%). Multivariate analysis results supported these findings (hazard ratio [HR] 0.61 for relapse, P = 0.017 and HR 0.72 for OS, P = 0.016). However, the KIR-ligand mismatch effect was not observed in patients with KIR-ligand mismatch types other than HLA-C2 and those using CNI/MMF for GVHD prophylaxis. These results suggest that HLA-C2 mismatch in CBT using CNI/MTX as GVHD prophylaxis may improve the outcomes of patients with AML.

Prognostic Factors for Outcomes of Allogeneic HSCT for Children and Adolescents/Young Adults with CML in the TKI Era

BACKGROUND

The breakthrough effects of tyrosine kinase inhibitors (TKIs) have lessened indications for allogeneic hematopoietic stem cell transplantation (HSCT) in chronic myeloid leukemia (CML). However, HSCT is still attractive for children and adolescents/young adults (AYAs) requiring lifelong TKI therapy. Nevertheless, little has been reported on the outcomes of large clinical studies of HSCT targeting these age groups.

OBJECTIVE

This study aimed to identify prognostic factors for the outcomes of HSCT, including reduced-intensity conditioning (RIC)-HSCT, for children and AYAs with CML in the TKI era.

STUDY DESIGN

We performed a registry analysis for 200 patients with CML aged <30 years who underwent pretransplant TKI therapy from the observational nationwide database established by the Japanese Society for Transplantation and Cellular Therapy. The patients received bone marrow (BM), peripheral blood (PB), or cord blood (CB) from either related or unrelated donors. The indication for HSCT for individual patients was determined by the institution according to European LeukemiaNet recommendations and other guidelines.

RESULTS

The 5-year overall survival (OS) rates for patients with chronic phase (CP) (n = 124), accelerated phase (AP) (n = 23), and blastic phase (BP) (n = 53) at diagnosis were 82.8%, 71.1%, and 73.3%, respectively, with no significant difference (P = 0.3293). The strongest predictor of engraftment was transplant source, with CB (hazard ratio [HR], 0.33) and PB (HR, 2.00) (compared with BM) being independent unfavorable and favorable predictors, respectively. Transplant source was also an independent predictor of chronic GVHD, with PB (HR, 1.81) and CB (HR, 0.39) (compared with BM) being unfavorable and favorable predictors, respectively. The strongest predictor of OS rate for patients with CP at diagnosis was disease phase at HSCT, with second or greater CP, AP, or BP (HR, 2.81) (compared with first CP [CP1]) being an unfavorable predictor. In addition, patients with CP at diagnosis who had major and complete molecular responses at HSCT had excellent outcomes, with 5-year OS rates of 100% and 94.4%, respectively. The 5-year OS rate was compared between RIC (n = 31) and myeloablative conditioning (MAC) (n = 58) in patients with CP1, both of which were 89.3%, with no significant difference (P = 0.9440). On univariate analysis for the RIC cohort with CP at diagnosis, the age at HSCT (HR, 1.27) (increase per year) and the time from diagnosis to HSCT (HR, 1.83) (increase per year) were significant predictors for OS.

CONCLUSIONS

Our study demonstrates that RIC may be an appropriate alternative to MAC for children and AYAs with CP1. As for the transplant source, we recommend first selecting BM because of a higher engraftment rate compared to CB and a lower incidence of chronic GVHD compared to PB. Although HSCT in the status of a major molecular response is desirable, it is not advisable to continue TKI pointlessly long because age at HSCT and timing of HSCT are prognostic factors that determine survival. The decision to perform RIC-HSCT instead of continuing TKI should be carefully made, considering the possibility of transplant-related complications.

Outcome of therapy-related myelodysplastic syndrome and oligoblastic acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation: A propensity score matched analysis

Therapy-related myelodysplastic syndromes (t-MDS) are generally progressive and associated with poorer outcomes than de novo MDS (d-MDS). To evaluate the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for t-MDS, we conducted a propensity score matched-pair analysis of patients with t-MDS and d-MDS using a nationwide database. A total of 178 patients with t-MDS underwent allo-HSCT between 2001 and 2018, and 178 out of 3,123 patients with d-MDS were selected. The probability of 3-year overall survival rate was 40.0% and 50.0% in the t-MDS and d-MDS groups, respectively (P=0.032). The 3-year transplant-related mortality was 30.9% and 19.0% in the t-MDS and d-MDS groups, respectively (P=0.005). The 3-year cumulative incidence of relapse was 32.8% and 33.0% in the t-MDS and d-MDS groups, respectively (P=0.983). A multivariate analysis identified four adverse factors for overall survival in the t-MDS group: age ≥55 years (hazard ratio [HR], 2.09; 95% CI, 1.11-3.94; P=0.023), the poor cytogenetic risk group (HR, 2.19; 95% CI, 1.40-4.19; P=0.019), performance status at allo-HSCT 2-4 (HR, 2.14; 95% CI, 1.19-3.86; P=0.011), and a shorter interval from diagnosis to transplantation (<8 months) (HR, 1.61; 95% CI, 1.00-2.57; P=0.048). The most frequent cause of transplant-related death was the infectious complications (21.6%) in t-MDS group and organ failure (12.5%) in d-MDS group. In conclusion, allo-HSCT potentially provides long-term remission in patients with t-MDS; however, further efforts to reduce transplant-related death are needed. This article is protected by copyright. All rights reserved.

Allogeneic Hematopoietic Stem Cell Transplantation for Adult Philadelphia Chromosome-Negative B-Cell Acute Lymphoblastic Leukemia in Second Complete Remission

Even in the era of high-intensity chemotherapy, disease recurrence remains a major cause of treatment failure in adult patients with Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia (Ph-negative B-ALL). For patients who achieved second complete remission (CR2) with salvage chemotherapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) could be the best curative treatment. However, limited data are available on the outcomes of allo-HSCT for adult Ph-negative B-ALL in CR2 in the high-intensity chemotherapy era. We evaluated the transplantation outcomes of adult patients with Ph-negative B-ALL in CR2 compared with those in CR1. We also clarified the prognostic factors among adult allo-HSCT recipients with Ph-negative B-ALL in CR2. We conducted a nationwide retrospective study using the data form Japanese transplant registry database. Patients aged ≥16 years and underwent their first allo-HSCT between 2003 and 2017 were included. The 3-year overall survival (OS) rate of the patients in CR2 (n = 382) was significantly lower than that in first complete remission (n = 1375) (51.8% versus 68.1%; P < .001), accompanied by a higher relapse rate (34.2% versus 17.6% at 3 years; P < .001). In a multivariate analysis among CR2 patients, time from diagnosis to allo-HSCT (≤2 years) was a significant factor for OS (hazard ratio [HR] 1.87; P < .001) and relapse (HR = 1.88; P < .001), whereas age at allo-HSCT (≥30 years) was a significant factor for OS (HR = 2.10, P < .001) and nonrelapse mortality (HR = 2.68; P < .001). By assigning a score of 1 to each factor, the 3-year OS rate of CR2 patients significantly stratified: 70.7% in patients with score 0, 56.4% with score 1, and 28.4% with score 2 (P < .001). The survival outcomes of allo-HSCT in adult Ph-negative B-ALL patients in CR2 were inferior to those in CR1 in the high-intensity chemotherapy era, mainly because of the higher relapse rate. Among the CR2 patients, the short time between diagnosis and allo-HSCT was a significant risk factor for disease recurrence and overall mortality. Better disease control with novel treatment strategies may be needed for early relapse. In addition, the nonrelapse mortality rate in patients over 30 years of age was particularly high among CR2 patients, suggesting the need for improved supportive care for these patients. Further studies are warranted on the outcomes of allo-HSCT after achieving CR2 with novel drugs, such as inotuzumab ozogamicin and blinatumomab.

HLA 1-3 antigen-mismatched related peripheral blood stem cells transplantation using low-dose antithymocyte globulin versus unrelated cord blood transplantation

Little information is available regarding whether unrelated cord blood transplantation (CBT) or an HLA 1-3 antigen-mismatched related donor peripheral blood stem-cell transplantation (PBSCT) using low-dose anti-thymocyte globulin (ATG) is superior as an alternative transplantation for patients who lack an HLA-matched sibling or unrelated donor. Therefore, we evaluated 7861 patients with hematologic malignancies (aged 0 to 70 years) who received either a CBT without ATG (CBT-no ATG, n = 7034) or an HLA 1-3 antigen-mismatched related donor PBSCT using low-dose ATG (PBSCT-ATG, n = 827). CBT-no ATG was associated with significantly better overall survival (OS) than the use of a PBSCT-ATG (hazard ratio [HR], 0.77; p < .001), although PBSCT-ATG patients with an HLA 1 antigen-mismatch showed OS comparable to that in the CBT-no ATG group. Neutrophil and platelet engraftment was significantly delayed, whereas the incidences of nonrelapse mortality, and severe graft-versus-host disease (GVHD) were significantly lower in the CBT-no ATG group. The incidences of relapse and chronic GVHD were comparable between these donors. In conclusion, CBT-no ATG may be a better alternative than HLA-mismatched related donor PBSCT using low-dose ATG. Notably, HLA 2-3 antigen mismatch-related transplantation with low-dose ATG had significant adverse effects on transplantation outcomes.

Characterization of myeloid neoplasms following allogeneic hematopoietic cell transplantation

We compared characteristics of myeloid neoplasms (MNs) following allogeneic hematopoietic cell transplantation (HCT) versus autologous HCT using a Japanese HCT registry database. Among 43 788 patients who underwent allogeneic (n = 18 874) or autologous HCT (n = 24 914) for non-myeloid malignancies or non-malignant diseases, 352 developed MNs. The cumulative incidence of MNs was lower after allogeneic HCT than after autologous HCT (0.3% vs. 1.8% at 10 years, respectively, p < .001). Compared with autologous HCT, MNs following allogeneic HCT developed in younger patients (median, 42 vs. 57 years old, respectively) and sooner after HCT (median, 16 vs. 33 months, respectively). Approximately half of MNs following allogeneic HCT were donor-derived and occurred later than recipient-derived MNs (median, 26 vs. 6 months, respectively, p = .003). In multivariate analysis, reduced-intensity conditioning and cord blood transplantation were associated with MN development after allogeneic HCT. Overall survival was similar in patients who developed MNs following allogeneic versus autologous HCT (18% vs. 22% at 5 years, respectively, p = .48). Patient age ≥ 55 years, the presence of previous HCT, AML subtype, and chromosome 5 or 7 abnormalities were adverse factors for overall survival after MN diagnosis. Further research is warranted to elucidate the mechanisms of MN development following allogeneic HCT.

Risk factors and prognosis of non-infectious pulmonary complications after allogeneic hematopoietic stem cell transplantation

Non-infectious pulmonary complications (NIPCs) following allogeneic hematopoietic stem cell transplantation (HSCT) are relatively rare, but frequently fatal. This study investigated the pre-transplant risk factors for developing NIPCs using Japanese transplant registry database entries from 2001 to 2009. Among 13,573 eligible patients, 535 experienced NIPCs (3.9%). Multivariate analysis identified high recipient age (60 + years: HR 1.85, P = 0.003), HLA mismatch (HR 1.61, P < 0.001), female to male HSCT (HR 1.54, P < 0.001), and unrelated bone marrow transplantation (UR-BMT) (HR 3.88, P < 0.001) as significantly associated with an increased risk of NIPCs. In contrast, a non-total body irradiation (TBI) regimen with reduced intensity conditioning (RIC) were associated with a decreased risk of NIPCs compared with a cyclophosphamide (CY) + TBI regimen (busulfan + CY: HR 0.67, P = 0.009, other non-TBI: HR 0.46, P < 0.001), fludarabine-based RIC (HR 0.52, P < 0.001), and other RIC (HR 0.42, P = 0.003). The mortality rate was significantly worse for patients with NIPCs than those without (HR 1.54, 71 P < 0.001). This large-scale retrospective study suggests that both allo-reactions to donor cells and conditioning regimen toxicity contributed to NIPCs following HSCT.

Disease-specific impact of anti-thymocyte globulin in allogeneic hematopoietic cell transplantation: a nationwide retrospective study on behalf of the JSTCT, transplant complications working group

The disease-specific impact of anti-thymocyte globulin (ATG) in allogeneic hematopoietic cell transplantation (allo-HCT) has not been determined. We retrospectively assessed the impact of ATG in allo-HCT using nationwide registry data from the Japan Society for Transplantation and Cellular Therapy. We included patients who received their first allo-HCT between 2007 and 2018 for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or malignant lymphoma (ML). In total, 8747 patients were included: 7635 patients did not receive ATG and 1112 patients received ATG as GVHD prophylaxis. The median follow-up period of surviving patients was 1457 days. There was no significant impact of pretransplant ATG on the OS or NRM rates in patients with ALL, AML, or ML. In patients with MDS, the probability of 3-year OS was 53.3% in the non-ATG group and 64.2% in the ATG group (P = 0.001). The cumulative incidence rates of relapse and NRM at 3 years were 14.2% and 30.3% (95% CI 27.2-33.3%), respectively, in the non-ATG group and 17.1% and 18.1% in the ATG group (P = 0.15 and P < 0.001). The same finding was observed in a propensity-score matched cohort. Our study suggests that the clinical benefit of ATG could vary among hematological diseases.

Risk and predictive factors for candidemia after allogeneic hematopoietic cell transplantation: JSTCT Transplant Complications Working Group

BACKGROUND

Although antifungal prophylaxis that covers Candida species is a standard of care in allogeneic hematopoietic cell transplantation (HCT), candidemia mainly caused by non-albicans Candida species still occurs and is associated with a high mortality rate.

OBJECTIVE

This study aimed to evaluate the risk factors for candidemia after allogeneic HCT. Particularly, we evaluated the impact of patient factors such as hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and performance status (PS) in addition to well-recognized risk factors including donor type, delayed engraftment and graft-versus-host disease (GVHD).

STUDY DESIGN

By using data from a Japanese transplant registry database, we analyzed 26,236 pediatric and adult patients with hematological malignancies who underwent their first allogeneic HCT. The posttransplant period was divided into early (days 0-40), late (days 41-100) and very late (days 101-365) phases RESULTS: The 1-year cumulative incidence of candidemia was 1.8%. When we analyzed pretransplant factors, age ≥ 40 years (hazard ratio [HR] 1.85), male (HR 1.34), HCT-CI (HCT-CI 1-2, HR 1.56; HCT-CI ≥ 3, HR 2.21), PS ≥ 2 (HR 2.01), high-risk disease (HR 1.78) and donor type including HLA-mismatched related donor (MMRD) (HR 1.96), HLA-mismatched unrelated donor (HR 2.05) and cord blood (CB) (HR 2.85) were significantly associated with an increased incidence of candidemia. Focusing on the early phase (days 0-40), HCT-CI, PS, high-risk disease and CB transplantation together with engraftment and severe acute GVHD significantly affected the development of candidemia. In the late phase (days 41-100), higher HCT-CI, male, and donor type including MMRD, and CB were associated with the occurrence of candidemia together with acute GVHD and disease relapse. In the very late phase (days 101-365), HCT-CI ≥ 3 and high-risk disease significantly affected the occurrence of candidemia together with acute and chronic GVHD, and disease relapse.

CONCLUSIONS

In addition to well-recognized risk factors including donor type, engraftment and GVHD, patient factors such as HCT-CI and PS were associated with the development of candidemia, which suggests that severely ill patients with transplantation-associated complications are more likely to develop candidemia.

Anti-thymocyte globulin could potentially overcome an adverse effect of acute GVHD in matched-related PBSCT

BACKGROUND

Previous Japanese studies have shown that bone marrow transplantation (BMT) is associated with a better survival compared with peripheral blood stem cell transplantation (PBSCT) from matched related donors (MRDs). PBSCT recipients showed a higher incidence of severe graft-versus-host disease (GVHD) and non-relapse mortality (NRM) than BMT recipients. In recent years, the efficacy and safety of anti-thymocyte globulin (ATG) for PBSCT recipients has been reported from around the world.

OBJECTIVE

We aimed to compare BMT and PBSCT to identify current improvements and unmet needs among PBSCT recipients from MRDs. Moreover, we evaluated the impact of ATG administration on the outcomes for PBSCT recipients.

STUDY DESIGN

We retrospectively analyzed patients aged 16 years or older with acute leukemia, myelodysplastic syndrome, or chronic myeloid leukemia who received their first BMT or PBSCT from MRDs between 2009 and 2018 in Japan.

RESULTS

In total, 3599 transplantations were performed (BMT, 1218; PBSCT without ATG [PBSCT-ATG(-)], 2288; and PBSCT with ATG [PBSCT-ATG(+)], 93). The PBSCT-ATG(-) group had a higher NRM rate (hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.08-1.57; p = 0.005) and lower overall survival (OS) rate (HR, 1.16; 95% CI, 1.04-1.30; p = 0.011) than the BMT group. Furthermore, the PBSCT-ATG(-) group had a higher incidence of grade III-IV, stage 2-4 gut, high-risk, and steroid-refractory acute GVHD than the BMT group. Acute GVHDs had a negative impact on NRM and OS rates. PBSCT-ATG(-) was also associated with a higher risk of chronic GVHD (HR: 1.89; 95% CI: 1.24-1.57; p < 0.001) and extensive chronic GVHD (HR: 1.44; 95% CI: 1.23-1.68; p < 0.001). The incidence 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 rate of patients with acute GVHD in the three donor groups was similar. Patients treated with reduced-intensity conditioning in the PBSCT-ATG(+) group had a higher relapse rate and lower OS rate than those in the BMT group.

CONCLUSIONS

In this Japanese cohort, standard calcineurin inhibitor-based GVHD prophylaxis was not sufficient for PBSCT recipients from MRDs because of the high incidence of severe acute GVHD. Moreover, prophylactic ATG was found to be a promising strategy against GVHD.

Impact of donor types on reduced-intensity conditioning allogeneic stem cell transplant for mature lymphoid malignancies

We retrospectively compared the outcomes of reduced-intensity conditioning (RIC) transplantation from matched related donors (MRD; n = 266), matched unrelated donors (MUD; n = 277), and umbilical cord blood (UCB; n = 513) for mature lymphoid malignancies. The 3-year overall survival rates for the MRD, MUD, and UCB groups were 54%, 59%, and 40%, respectively (P < 0.001). Multivariate analysis showed no differences in survival between the MRD group and the MUD or UCB group. However, survival was significantly affected by the conditioning regimen and graft-versus-host disease (GVHD) prophylaxis in the UCB group, but not in the MRD and MUD groups. Notably, multivariate analysis showed that the risk of overall mortality in the UCB recipients who received the optimal conditioning regimen and GVHD prophylaxis (n = 116) was lower than that in the MRD group (relative risk [RR], 0.69; P = 0.03) and tended to be lower than that in the MUD group (RR, 0.75; P = 0.09). Our results suggest that UCB transplantation performed with the optimal conditioning regimen and GVHD prophylaxis is highly effective. Moreover, UCB is readily available. Thus, UCB transplantation with the optimal conditioning regimen and GVHD prophylaxis is preferable to MUD transplantation when MRD are not available in the setting of RIC transplantation for mature lymphoid malignancies.

Retrospective Analysis of Autologous Stem Cell Transplantation for AL Amyloidosis: A Study from the Multiple Myeloma Working Group of the Japan Society for Hematopoietic Cell Transplantation

Autologous stem cell transplantation (ASCT) is the standard of care for eligible patients with light-chain (AL) amyloidosis, but little is known about it in Asian populations. To investigate the outcome of and prognostic factors for ASCT, we retrospectively analyzed ASCT cases registered to the Transplant Registry Unified Management Program between December 1999 and December 2015, with extra clinical information collected through a secondary survey. The primary endpoint was overall survival (OS). Hematologic response, organ response, and transplantation-related mortality were analyzed as secondary endpoints. The database search identified 330 patients (median age, 57 years; range, 31 to 74), and the secondary survey provided details for the 110 patients (33.3%) included in the study cohort. Fewer than 3 organs were involved in 56.4% of the patients, with cardiac involvement in 57.3%. Performance status (PS) was 0 to 1 in 83.6%. The conditioning melphalan dose was reduced in 54.6%. Overall hematologic response was a partial response or better in 77.6% of the patients and a complete response in 49.3%. The 5-year OS was 70.1%. A PS of 0 to 1 was associated with a significantly better prognosis in terms of OS. Although survival after ASCT for AL amyloidosis improved over time, poor PS and cardiac involvement had negative impacts on prognosis. The early mortality after ASCT was 6.4%. Poor PS and cardiac involvement led to high early mortality. A brain natriuretic peptide (BNP) level of 400 pg/mL was associated with worse OS. Our study has several limitations inherent to a retrospective analysis using a questionnaire. The depth of response and biomarker responses were significantly limited by the degree of missing data. Nonetheless, our data support the importance of careful patient selection for good outcomes of ASCT in patients with AL amyloidosis. In our cohort, poor PS and cardiac involvement had a negative impact on prognosis, and BNP level was a useful prognostic factor.

Improved survival of multiple myeloma patients treated with autologous transplantation in the modern era of new medicine

New drugs for multiple myeloma (MM) have dramatically improved patients’ overall survival (OS). Autologous stem cell transplantation (ASCT) remains the mainstay for transplant‐eligible MM patients. To investigate whether the post‐ASCT prognosis of MM patients has been improved by new drugs, we undertook a retrospective observational analysis using the Transplant Registry Unified Management Program database in Japan. We analyzed 7323 patients (4135 men and 3188 women; median age, 59 years; range 16‐77 years) who underwent upfront ASCT between January 2007 and December 2018. We categorized them by when they underwent ASCT according to the drugs’ introduction in Japan: group 1 (2007‐2010), group 2 (2011‐2016), and group 3 (2017‐2018). We compared the groups’ post‐ASCT OS. The 2‐year OS rates (95% confidence interval [CI]) of groups 1, 2, and 3 were 85.8% (84.1%‐87.4%), 89.1% (88.0%‐90.1%), and 92.3% (90.0%‐94.2%) (P < .0001) and the 5‐year OS (95% CI) rates were 64.9% (62.4%‐67.3%), 71.6% (69.7%‐73.3%), and not applicable, respectively (P < .0001). A multivariate analysis showed that the post‐ASCT OS was superior with these factors: age less than 65 years, performance status 0/1, low International Staging System (ISS) stage, receiving SCT for 180 days or less post‐diagnosis, better treatment response pre‐ASCT, later year of ASCT, and receiving SCT twice. A subgroup analysis showed poor prognoses for the patients with unfavorable karyotype and poor treatment response post‐ASCT. The post‐ASCT OS has thus improved over time (group 1 < 2 < 3) with the introduction of new drugs for MM. As the prognosis of high‐risk‐karyotype patients with ISS stage III remains poor, their treatment requires improvement.

Impact of chronic GVHD on QOL assessed by visual analogue scale in pediatric HSCT survivors and differences between raters: a cross-sectional observational study in Japan

A nationwide cross-sectional survey was conducted in long-term survivors of allogeneic hematopoietic stem cell transplantation (HSCT) in childhood to investigate the effect of chronic graft-versus-host disease (cGVHD) on quality of life (QOL) and differences in QOL assessments between raters. QOL was evaluated by a visual analogue scale (VAS). Assessments were compared between the survivor, guardian, and attending pediatrician for those aged 15 years or younger, and between the survivor and attending pediatrician for those aged 16 years or older. For cGVHD, severity scores were obtained by organ and their association with the VAS score was analyzed. The average pediatrician-rated VAS score was higher than that of other raters for both patient age groups (< 15 years and > 16 years). By organ, involvement of the skin, digestive organs, and joints in GVHD affected the VAS scores. A high joint score was associated with a low VAS score, and conversely, a high lung score was associated with a low pediatrician-rated VAS score. Our results indicate that differences between raters must be considered when evaluating QOL of HSCT survivors, because patients appeared to experience grater inconvenience and difficulties due to joint GVHD than their pediatricians perceived.

Off-the-shelf bone marrow-derived mesenchymal stem cell treatment for acute graft-versus-host disease: real-world evidence

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.

Altered effect of killer immunoglobulin-like receptor-ligand mismatch by graft versus host disease prophylaxis in cord blood transplantation

The role of killer immunoglobulin-like receptor-ligand mismatch (KIR-ligand mismatch) between donors and recipients undergoing cord blood transplantation (CBT) is controversial. If each immunosuppressant differently affects natural killer (NK) cell function, the effect of KIR-ligand mismatch may be altered depending on the type of graft versus host disease (GVHD) prophylaxis. To verify this hypothesis, the difference in the effect of KIR-ligand mismatch was retrospectively assessed between patients who received CBT for acute leukemia, myelodysplastic syndrome, or chronic myeloid leukemia, as well as GVHD prophylaxis comprising tacrolimus plus methotrexate (MTX) or mycophenolate mofetil (MMF). In the MMF group (n = 1363), KIR-ligand mismatch augmented the incidence of non-relapse mortality (NRM; hazard ratio [HR], 1.40; P = 0.008), which worsened overall survival (OS; HR, 1.30, P = 0.0077). In the analysis of each KIR-ligand mismatch type, HLA-C2 mismatch had a favorable effect on relapse incidence (HR, 0.56; P = 0.0043) and OS (HR, 0.72; P = 0.037) only in the MTX group. In the MMF group, HLA-A3/A11 mismatch worsened NRM (HR, 1.93; P < 0.001) and OS (HR, 1.48; P = 0.014). These results imply that the effects of KIR-ligand mismatch differ with the type of GVHD prophylaxis and that assessing the KIR-ligand mismatch status is important for CBT.

Prognostic value of the revised International Prognostic Scoring System five-group cytogenetic abnormality classification for the outcome prediction of hematopoietic stem cell transplantation in pediatric myelodysplastic syndrome

Cytogenetic abnormalities are a major risk factor for relapse after hematopoietic stem cell transplantation (HSCT) for myelodysplastic syndrome (MDS). We aimed to evaluate the value of the five-group cytogenetic classification according to the revised International Prognostic Scoring System (R-IPSS) for predicting the outcome after HSCT in pediatric patients with MDS. We retrospectively analyzed the Japanese registration data of 242 pediatric patients with MDS. According to the R-IPSS classification, 112 (45.5%) patients had good, 55 (22.7%) had intermediate, 64 (26.4%) had poor, and 11 (4.6%) had very poor cytogenetics. The 5-year overall survival (5yOS) was 72%, 69%, 59%, and 30% in the good, intermediate, poor, and very poor cytogenetic subgroups (p = 0.026), respectively. The very good, good, and intermediate subgroups were grouped into a "standard" subgroup and reclassified into three subgroups (standard, poor, and very poor). Patients with very poor risk had worse 5yOS (hazard ratio 2.17, 95% confidence interval (CI) 1.02-4.61; p = 0.04) and a much higher 5yCIR (hazard ratio 2.52, 95% CI 1.05-6.04; p = 0.04) than those of patients in the standard group in the multivariate analysis, indicating that very poor risk cytogenetic characteristics independently predicted worse outcome after HSCT in pediatric patients with MDS.

Impact of HLA disparity on the risk of overall mortality in patients with grade II-IV acute GVHD on behalf of the HLA Working Group of Japan Society for Hematopoietic Cell Transplantation

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.

Effect of high-dose chemotherapy plus stem cell rescue on the survival of patients with neuroblastoma modified by MYCN gene gain/amplification and remission status: a nationwide registration study in Japan

In high-risk neuroblastoma, the presence of an MYCN gain/amplification (MYCN-GA) is not always a risk factor of cancer-specific death. We herein examined the effect modification of high-dose chemotherapy with autologous hematopoietic stem cell rescue (HDC-autoSCR) in terms of the interaction between MYCN status and remission status (complete remission or very good partial remission [CR/VGPR] vs. partial remission or less [≤PR]). The present study recruited patient data from 1992 to 2017 in the Japan Society of Hematopoietic Cell Transplantation's national registry. The MYCN status was known in 586 of 950 patients with a single course of HDC-autoSCR. Cumulative hazard curves for neuroblastoma-specific death showed that a subgroup with MYCN-GA and ≤PR had a significantly poorer prognosis than three other subgroups, namely, the MYCN-NGA/ ≤ PR, MYCN-NGA/CR/VGPR, and MYCN-GA/CR/VGPR subgroups even after adjusting for non-infants and stage IV disease (hazard ratio: 2.79; 95% confidence interval: 1.91-4.09; P < 0.001). The interaction between MYCN-GA and ≤PR was significant (p_interaction = 0.006). Hence, the patients with MYCN-GA with non-remission status at HDC-autoSCR had a significantly poorer prognosis than the other subgroups, suggesting that HDC-autoSCR may be effective in patients with CR/VGPR regardless of MYCN gene status and in patients with MYCN-NGA regardless of remission status.

Personalized prediction of overall survival in patients with AML in non-complete remission undergoing allo-HCT

Allogenic hematopoietic stem cell transplantation (allo‐HCT) is the standard treatment for acute myeloid leukemia (AML) in non‐complete remission (non‐CR); however, the prognosis is inconsistent. This study aimed to develop and validate nomograms and a web application to predict the overall survival (OS) of patients with non‐CR AML undergoing allo‐HCT (cord blood transplantation [CBT], bone marrow transplantation [BMT], and peripheral blood stem cell transplantation [PBSCT]). Data from 3052 patients were analyzed to construct and validate the prognostic models. The common significant prognostic factors among patients undergoing allo‐HCT were age, performance status, percentage of peripheral blasts, cytogenetic risk, chemotherapy response, and number of transplantations. The conditioning regimen was a significant prognostic factor only in patients undergoing CBT. Compared with cyclophosphamide/total body irradiation, a conditioning regimen of ≥3 drugs, including fludarabine, with CBT exhibited the lowest hazard ratio for mortality (0.384; 95% CI, 0.266–0.554; p < 0.0001). A conditioning regimen of ≥3 drugs with CBT also showed the best leukemia‐free survival among all conditioning regimens. Based on the results of the multivariable analysis, we developed prognostic models showing adequate calibration and discrimination (the c‐indices for CBT, BMT, and PBSCT were 0.648, 0.600, and 0.658, respectively). Our prognostic models can help in assessing individual risks and designing future clinical studies. Furthermore, our study indicates the effectiveness of multi‐drug conditioning regimens in patients undergoing CBT.

Reduced leukemia relapse through cytomegalovirus reactivation in killer cell immunoglobulin-like receptor-ligand-mismatched cord blood transplantation

Cytomegalovirus (CMV) reactivation in cord blood transplantation (CBT) may result in the proliferation and maturation of natural killer (NK) cells. Similarly, a mismatch of the killer cell immunoglobulin-like receptor (KIR)-ligand induces NK cell activation. Therefore, if CMV reactivation occurs in the presence of KIR-ligand mismatch, it might improve CBT outcomes. We assessed the difference in the effect of CMV reactivation in the presence of KIR-ligand mismatch on disease relapse in the graft-versus-host direction. A total of 2840 patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, and chronic myeloid leukemia were analyzed. Among those with a HLA-Bw4/A3/A11 (KIR3DL-ligand) mismatch, CMV reactivation up to 100 days following CBT had a favorable impact on relapse (18.9% vs. 32.9%, P = 0.0149). However, this effect was not observed in cases without the KIR3DL-ligand mismatch or in those with or without a HLA-C1/C2 (KIR2DL-ligand) mismatch. The multivariate analysis suggested that CMV reactivation had a favorable effect on relapse only in cases with a KIR3DL-ligand mismatch (hazard ratio 0.54, P = 0.032). Moreover, the interaction effect between CMV reactivation and KIR3DL-ligand mismatch on relapse was significant (P = 0.039). Thus, our study reveals the association between KIR-ligand mismatches and CMV reactivation, which will enhance CBT outcomes.

Analysis of Relationships between Immune Checkpoint and Methylase Gene Polymorphisms and Outcomes after Unrelated Bone Marrow Transplantation

Simple Summary

Hematopoietic stem-cell transplantation (HSCT) is a curative therapy for blood disorders. Unrelated bone marrow transplantation (uBMT) is a type of allogeneic HSCT that uses the bone marrow of an unrelated donor. While HLA mismatch is a risk factor for poor outcomes in HSCT, such as graft-versus-host disease (GVHD), the importance of non-HLA single-nucleotide polymorphisms (SNPs) remains unclear. The clinical application of immune checkpoint and chromatin methylation inhibitors to cancer has been attracting attention. In the present study, we retrospectively genotyped five SNPs in four immune checkpoint genes, BTLA, PD-1, LAG3, and CTLA4, and two SNPs in methylase genes, DNMT1 and EZH2, in 999 uBMT pairs. Although no correlations were observed between these SNPs and post-uBMT outcomes, recipient EZH2 SNP exhibited a low p-value in the analysis of grade 2–4 acute GVHD (p = 0.010). This SNP may be useful for outcome predictions and needs to be confirmed in a larger-scale study.

Abstract

Unrelated bone marrow transplantation (uBMT) is performed to treat blood disorders, and it uses bone marrow from an unrelated donor as the transplant source. Although the importance of HLA matching in uBMT has been established, that of other genetic factors, such as single-nucleotide polymorphisms (SNPs), remains unclear. The application of immunoinhibitory receptors as anticancer drugs has recently been attracting attention. This prompted us to examine the importance of immunoinhibitory receptor SNPs in uBMT. We retrospectively genotyped five single-nucleotide polymorphisms (SNPs) in the immune checkpoint genes, BTLA, PD-1, LAG3, and CTLA4, and two SNPs in the methylase genes, DNMT1 and EZH2, in 999 uBMT donor–recipient pairs coordinated through the Japan Marrow Donor Program matched at least at HLA-A, -B, and -DRB1. No correlations were observed between these SNPs and post-uBMT outcomes (p > 0.005). This result questions the usefulness of these immune checkpoint gene polymorphisms for predicting post-BMT outcomes. However, the recipient EZH2 histone methyltransferase gene SNP, which encodes the D185H substitution, exhibited a low p-value in regression analysis of grade 2–4 acute graft-versus-host disease (p = 0.010). Due to a low minor allele frequency, this SNP warrants further investigation in a larger-scale study.

Impact of the combination of donor age and HLA disparity on the outcomes of unrelated bone marrow transplantation

Impact of donor age considering HLA disparity on hematopoietic cell transplantation (HCT) outcomes has not been fully evaluated. We evaluated 8486 patients who received unrelated bone marrow transplantation (UR-BMT) from 8/8 or 7/8 HLA-matched donors. Compared to 8/8 HLA-matched younger donors (<40 years), 8/8 HLA-matched older donors (subdistribution hazard ratio [SHR], 1.16; 95% CI, 0.97-1.38) and 7/8 HLA-matched younger donors (SHR, 1.33; 95% CI, 1.11-1.58) were associated with increased risk of grade III-IV acute graft-versus-host disease (aGVHD). 7/8 HLA-matched older donors had further increased risk (SHR, 2.00; 95% CI, 1.68-2.38) due to interaction between donor age and HLA disparity (p for interaction = 0.038). Progression-free survival (PFS) after UR-BMT with 8/8 HLA-matched younger donors was comparable to that after UR-BMT with 8/8 HLA-matched older donors, whereas UR-BMT with 7/8 HLA-matched younger or older donors was significantly associated with lower PFS than UR-BMT with 8/8 HLA-matched younger donors (younger donor; HR, 1.12; 95% CI, 1.04-1.21, older donor; HR, 1.28; 95% CI, 1.17-1.40; p for interaction = 0.079). In conclusion, adverse effect of increased donor age requires attention, especially in HLA-mismatched UR-BMT due to interaction between donor age and HLA disparity. Intensive aGVHD prophylaxis may be required to improve outcomes after HCT with mismatched older donors.

Heterogeneous impact of cytomegalovirus reactivation on nonrelapse mortality in hematopoietic stem cell transplantation

Cytomegalovirus (CMV) infection is a major complication in allogeneic stem cell transplantation. The utility of CMV prophylaxis with letermovir has been reported; however, the specific applications remain unclear. In this study, we retrospectively analyzed large-scale registry data (N = 10 480) to clarify the risk factors for nonrelapse mortality (NRM) in connection with CMV reactivation. First, we identified risk factors for CMV reactivation using multivariate analysis and developed a scoring model. Although the model effectively stratified reactivation risk into 3 groups (43.7% vs 60.9% vs 71.5%; P < .001), the 3-year NRM was significantly higher in patients with CMV reactivation, even in the low (20.9% vs 13.0%, P < .001), intermediate (21.4% vs 15.6%; P < .001), and high (29.3% vs 18.0%; P < .001) reactivation risk groups. Next, survival analysis considering competing risks, time-dependent covariates, and interaction terms for exploring the heterogeneous impact of CMV reactivation on NRM in the training cohort revealed that chronic myeloid leukemia (CML) (hazard ratio [HR], 1.76; 95% confidence interval [CI], 1.05-2.96; P = .033), good performance status (PS) (HR, 1.42; 95% CI, 1.04-1.94; P = .028), HLA-matched donor (HR, 1.34; 95% CI, 1.06-1.70; P = .013), and standard-risk disease (HR, 1.28; 95% CI, 1.04-1.58; P = .022) were associated with increased NRM. In the test cohort, CMV reactivation was significantly associated with increased 3-year NRM among patients with 2 to 4 factors (22.1% vs 13.1%; P < .001) but was comparable among patients with 0 or 1 factor (23.2% vs 20.4%; P = .62). We propose that CMV prophylaxis should be determined based on reactivation risk, as well as these other factors.

Measurable residual disease affects allogeneic hematopoietic cell transplantation in Ph+ ALL during both CR1 and CR2

Although measurable residual disease (MRD) at the time of allogeneic hematopoietic cell transplantation (allo-HCT) has been reported to be an important prognostic factor for Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) during first complete remission (CR1), the prognostic impact of MRD is unclear during second CR (CR2). To clarify the impact of MRD for both CR1 and CR2, we analyzed data from a registry database including 1625 adult patients with Ph+ ALL who underwent first allo-HCT during either CR1 or CR2 between 2002 and 2017. Adjusted overall and leukemia-free survival rates at 4 years were 71% and 64%, respectively, for patients undergoing allo-HCT during CR1 with MRD-, 55% and 43% during CR1 with MRD+, 51% and 49% during CR2 with MRD-, and 38% and 29% during CR2 with MRD+. Although survival rates were significantly better among patients with CR1 MRD- than among patients with CR2 MRD-, no significant difference was observed in survival rate between patients with CR1 MRD+ and CR2 MRD-. Relapse rates after 4 years were 16% in patients with CR1 MRD-, 29% in CR1 MRD+, 21% in patients with CR2 MRD-, and 46% in patients with CR2 MRD+. No significant difference was identified in relapse rate between patients with CR1 MRD- and CR2 MRD-. CR2 MRD- was not a significant risk factor for relapse in multivariate analysis (hazard ratio, 1.26; 95% confidence interval, 0.69-2.29; P = .45 vs CR1 MRD-). MRD at time of allo-HCT was an important risk factor in patients with Ph+ ALL during both CR1 and CR2.