Allogeneic hematopoietic cell transplantation for acute myeloid leukemia during first complete remission: a clinical perspective

Age and allogeneic hematopoietic cell transplantation outcomes in acute myeloid leukemia

Although several studies have reported significant effects of patient age on outcomes of allogeneic hematopoietic cell transplantation (HCT), the prognostic relevance of age must be determined separately for myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC). We analyzed Japanese nationwide transplantation registry data of patients aged 20-79 years with acute myeloid leukemia who underwent allogeneic HCT using MAC (n = 7525) or RIC (n = 3154) between 2008 and 2019. Patient were divided into six groups by age, with each group representing a decade, and overall survival (OS), relapse, and non-relapse mortality (NRM) were compared between adjacent age groups. The adverse impact of age on OS increased each decade starting at age 40 among patients receiving MAC, but only differed significantly between patients in their 50s and 60s among those receiving RIC. In patients receiving both MAC and RIC, the detrimental effect of advanced age on OS was accompanied by an increased risk of NRM. These findings show that age affects NRM and OS significantly, but differs depending on conditioning intensity. RIC mitigates the adverse prognostic impact of older age and is thus considered a reasonable option for older patients.

Conditioning regimens for allogeneic hematopoietic cell transplantation in acute myeloid leukemia: Real-world data from the Japanese registry studies

Conditioning regimens play a crucial role in preventing relapse of acute myeloid leukemia (AML) following allogeneic hematopoietic cell transplantation (HCT). In early times, myeloablative conditioning was used exclusively, but it was associated with significant toxicity. However, the advent of reduced-intensity conditioning has allowed allogeneic HCT to be performed more safely, leading to an expansion of our choices for conditioning regimens. As the transplantation methods have become highly diversified, it is reasonable to determine an optimal conditioning regimen in consideration of patient-, disease-, and transplantation-related factors. In this context, large-scale registry-based studies provide real-world data to allow for a detailed evaluation of the utility of individual conditioning regimens in specific clinical settings. The Japanese Society for Transplantation and Cellular Therapy has been conducting a nationwide survey for HCT since 1993 that currently covers >99% of all the transplantation centers nationwide, and >1,000 allogeneic HCTs performed for adults with AML are registered per year. We have been using the registry data to implement a number of studies focusing on adults with AML, and the large number of patients registered consecutively from nearly all transplantation centers nationwide represent real-world practice in Japan. This article reviews and discusses the results obtained from our registry-based studies pertaining to various conditioning regimens.

Cachectic muscle wasting in acute myeloid leukaemia: a sleeping giant with dire clinical consequences

Acute myeloid leukaemia (AML) is a haematological malignancy with poor survival odds, particularly in the older (>65 years) population, in whom it is most prevalent. Treatment consists of induction and consolidation chemotherapy to remit the cancer followed by potentially curative haematopoietic cell transplantation. These intense treatments are debilitating and increase the risk of mortality. Patient stratification is used to mitigate this risk and considers a variety of factors, including body mass, to determine whether a patient is suitable for any or all treatment options. Skeletal muscle mass, the primary constituent of the body lean mass, may be a better predictor of patient suitability for, and outcomes of, AML treatment. Yet skeletal muscle is compromised by a variety of factors associated with AML and its clinical treatment consistent with cachexia, a life-threatening body wasting syndrome. Cachectic muscle wasting is associated with both cancer and anticancer chemotherapy. Although not traditionally associated with haematological cancers, cachexia is observed in AML and can have dire consequences. In this review, we discuss the importance of addressing skeletal muscle mass and cachexia within the AML clinical landscape in view of improving survivability of this disease.

Syngeneic hematopoietic stem cell transplantation for acute myeloid leukemia: a propensity score-matched analysis

The present study evaluated outcomes and prognostic factors in adult patients with acute myeloid leukemia (AML) after syngeneic hematopoietic stem cell transplantation (HSCT). Among patients in first complete remission (CR1), outcomes of syngeneic HSCT (Syn) were compared with those of autologous HSCT (Auto), allogeneic HSCT from human leukocyte antigen (HLA)-matched sibling donor (MSD), or allogeneic HSCT from HLA-matched unrelated donor (MUD). Among 11,866 patients receiving first HSCT, 26 in the Syn group were analyzed. The 5-year overall survival (OS) rate, the cumulative incidence of relapse, and the cumulative incidence of non-relapse mortality (NRM) were 47.8%, 59.6%, and 4.6%, respectively. The OS was significantly better in patients in CR1 (n = 13) than in patients in non-CR1 (P = 0.012). Furthermore, 39 patients in CR1 each were assigned to the Auto, MSD, and MUD groups using propensity score matching. The 5-year OS in the Syn (68.4%) was not significantly different from those in the Auto (55.9%, P = 0.265), MSD (62.4%, P = 0.419), or MUD (63.7%, P = 0.409) groups. A higher relapse in the Syn than in the MSD and MUD groups was offset by lower NRM. In summary, syngeneic HSCT might be an alternative option for AML patients in CR1.

The evolving concept of indications for allogeneic hematopoietic cell transplantation during first complete remission of acute myeloid leukemia

The long-standing debate of whether patients with acute myeloid leukemia (AML) should proceed to allogeneic hematopoietic cell transplantation (HCT) during first complete remission (CR1) remains unsettled. Although allogeneic HCT during CR1 used to be recommended for those with intermediate or poor cytogenetics if they had a matched sibling donor, the concept of indications for allogeneic HCT during CR1 has been evolving by virtue of advances in understanding of the molecular pathogenesis of AML and innovations in transplantation practice attained over the last few decades. The incorporation of molecular profiles of leukemia has been shown to contribute to further refinements of risk classification that had previously relied mostly on cytogenetics, while the progress in transplantation procedures has made it possible to perform transplantations more safely even for patients without a matched sibling donor. These significant changes have underpinned the need to reappraise indications for allogeneic HCT during CR1 of AML. Improvements in clinical applications of genetic and measurable residual disease information as well as in transplantation technology are expected to further refine indications for allogeneic HCT during CR1, and thus promote an individualized approach for the treatment of AML.

Predicting non-relapse mortality following allogeneic hematopoietic cell transplantation during first remission of acute myeloid leukemia

The aim of this study was to develop a comprehensive system for predicting non-relapse mortality after allogeneic hematopoietic cell transplantation (HCT) during first complete remission (CR) of acute myeloid leukemia (AML). After dividing 2344 eligible patients randomly into a training set and a validation set, we first identified and scored five parameters, that is, age, sex, performance status, HCT-comorbidity index (HCT-CI), and donor type, on the basis of their impact on non-relapse mortality for patients in the training set. The non-relapse mortality-J (NRM-J) index using the sum of these scores was then applied to patients in the validation set, resulting in a clear differentiation of non-relapse mortality, with expected 2-year rates of 11%, 16%, 27%, and 33%, respectively (P < 0.001). The estimated c-statistic was 0.67, which was significantly higher than that of the European Society for Blood and Marrow Transplantation score (0.60, P = 0.002) and the HCT-CI (0.57, P < 0.001). The NRM-J index showed a significant association with overall survival, but not with relapse. Our findings demonstrate that the NRM-J index is useful for predicting post-transplant non-relapse mortality for patients with AML in first CR, for whom the decision of whether to perform allogeneic HCT is critical.

Comparative study of micro-transplantation from HLA fully mismatched unrelated and partly matched related donors in acute myeloid leukemia

Micro-transplantation (MST) by chemotherapy, combined with granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (GPBSC) infusion, from an HLA partial matched related donor has shown some encouraging effective therapy for acute myeloid leukemia (AML). However, the outcome of human leukocyte antigen (HLA) fully mismatched unrelated donor-derived MST in such patients is still unknown. In the present study, we compared the efficacy of HLA fully mismatched unrelated donor-derived MST, and partly matched related donor-derived MST, in AML of 126 patients from two centers in China, These patients, aged 16 to 65 years, were given three or four courses of MST, which consisted of a high dosage cytarabine followed by GPBSC from unrelated donor or related donor. There was a statistically significant difference in 3-year leukemia-free survival (LFS) and 3-year overall survival (OS) between the unrelated and the related group. The non-treatment-related mortality (NRM) rates of patients, and other adverse complications, were no different in the two groups. In conclusion, unrelated donor-derived MST is believed to be a safe treatment, with efficacy similar to or higher than related donor-derived MST. This result provides support for the potential of MST for expanding the donor selection. However, the specific mechanism of action needs further study.

Long-term results of reduced-intensity conditioning allogeneic hematopoietic cell transplantation for older patients with acute myeloid leukemia: a retrospective analysis of 10-year follow-up data

The long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) with reduced-intensity conditioning (RIC) remain inconclusive. To address this issue, we conducted a nationwide registry-based study of patients with acute myeloid leukemia (AML) age 50 years or older who underwent allogeneic HCT in complete remission using RIC (n = 284) or myeloablative conditioning (MAC, n = 190) between 2002 and 2007. The median follow-up period for surviving patients was 10.1 years for RIC recipients and 10.4 years for MAC recipients. The 10-year probabilities of overall survival, relapse, and non-relapse mortality were 36.4%, 30.0%, and 35.7% for RIC recipients, and 39.8%, 26.3%, and 35.5% for MAC recipients, respectively. Multivariate analysis revealed that the conditioning intensity did not affect overall mortality (P = 0.184), relapse (P = 0.904), or non-relapse mortality (P = 0.387). For the 218 patients qualifying for propensity score-matched pairing (109 pairs), RIC was found to be associated with similar survival (P = 0.095) and relapse (P = 0.467), and significantly lower non-relapse mortality (P = 0.046) compared with MAC. Our results confirm the long-term efficacy of RIC allogeneic HCT for older patients with AML and mitigate concerns over an increase in late relapse.

Autologous hematopoietic cell transplantation for acute myeloid leukemia in adults: 25 years of experience in Japan

Autologous hematopoietic cell transplantation (HCT) has not gained universal popularity in the treatment of acute myeloid leukemia (AML), and its status remains unclear. To determine the implementation status and outcomes of autologous HCT for adults with AML in Japan, we analyzed data from 1,174 patients (including 446 with acute promyelocytic leukemia [APL]) who underwent autologous HCT between 1992 and 2016 consecutively reported to the Japanese nationwide transplantation registry. The annual number of transplantations peaked at 82 cases in 1997, and has recently remained at around 40 cases. The percentage of APL has increased sharply since 2004, and currently exceeds 70%. While most non-APL patients underwent autologous HCT during first complete remission (CR), transplantation during second CR has become mainstream for APL patients since the early 2000s. The 5-year survival, relapse, and non-relapse mortality rates were 55.3%, 42.1%, and 8.6% for non-APL patients, and 87.6%, 12.9%, and 3.4% for APL patients, respectively. Patients transplanted in the later period showed better survival than those transplanted in the earlier period, both for non-APL (P < 0.001) and APL (P = 0.036). These results clearly show the various changes in transplantation practice and post-transplant outcomes in Japan over the past 25 years.

Time-Varying Effects of Graft Type on Outcomes for Patients with Acute Myeloid Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

This study aimed to investigate time-varying effects of graft type on outcomes for patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplant. For this purpose we analyzed 3952 patients, 720 of whom underwent matched related bone marrow transplantation (BMT), 1004 matched related peripheral blood stem cell transplantation (PBSCT), 856 matched unrelated BMT, and 1372 umbilical cord blood transplantation (UCBT) during complete remission. The 4-year relapse-free survival (RFS) rates were 59.1%, 52.8%, 59.5%, and 50.6%, respectively. Compared with related BMT, related PBSCT, unrelated BMT, and UCBT were associated with higher risk of nonrelapse mortality and unrelated BMT and UCBT with lower risk of relapse. As a result, both RFS and overall survival were comparable between related BMT and unrelated BMT but were worse for related PBSCT and UCBT than for related BMT. Adverse impact of UCBT was observed only during the early phase of transplant, whereas that of related PBSCT continued even after 2 years post-transplant. Our findings raise concerns about the increased risk of late nonrelapse mortality with the use of PBSC grafts and suggest that related BMT is preferable to related PBSCT; matched unrelated BMT is the next choice in the absence of a matched related donor.

Haploidentical, Unmanipulated Granulocyte Colony-Stimulating Factor (G-CSF)-Primed Peripheral Blood Stem Cell Transplants for Acute Myeloid Leukemia (AML) in Remission: A Single Center Experience

Background

Data about application of related haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT) on patients with high-risk or intermediate-risk acute myeloid leukemia (AML) in the first complete remission (CR1) are lacking. In this study, we report the outcomes of using unmanipulated haploidentical allogeneic peripheral blood stem cell transplantation (haplo-PBSCT) as post-remission therapy for patients with high-risk or intermediate-risk AML in CR1.

Material/Methods

From January 2008 to July 2016, 33 patients diagnosed as high-risk or intermediate-risk AML in CR1 undergoing haplo-PBSCT in our institution were enrolled for analysis. The cumulative incidence of platelet and neutrophil recovery, the occurrence of acute graft-versus-host-disease (GVHD) and chronic GVHD, relapse and non-relapse mortality were assessed. Patients’ survival rates were estimated using the Kaplan-Meier method.

Results

The cumulative incidence of grade 2–4 acute GVHD, overall and extensive chronic GVHD was 18.2%, 9.1%, and 6.1%, respectively. 2-year probability of relapse was 9.1%. Disease-free survival and overall survival at 2 years were 72.7% and 75.8%, respectively.

Conclusions

Our results showed that unmanipulated haploidentical transplantation with G-CSF primed PBSC alone as a graft source could be an acceptable alternative post-remission treatment for high-risk or intermediate-risk AML patients in CR1 lacking a matched donor.

Unrelated donor hematopoietic stem cell transplantation for pediatric de novo acute myeloid leukemia with intermediate- or high-risk cytogenetics

The role of unrelated donor HSCT for children with de novo AML in CR1 is controversial. We performed this study to investigate the feasibility of unrelated donor HSCT who initially had intermediate- or high-risk cytogenetics. We retrospectively reviewed medical records of patients with AML who received unrelated HSCT in CR1 at Samsung Medical Center between November 2001 and January 2012. Patients were allocated based on karyotype at diagnosis as follows: (a) low-risk: inv(16), t(16;16), t(8;21), and t(15;17); (b) high-risk: -5, 5q-, -7, 3q abnormalities, t(8;16), t(6;9), t(6;11), t(6;21), t(10;11), complex karyotype (≥3 abnormalities), and acute megakaryocytic leukemia without t(1;22); and (c) IR: all the other karyotypes including normal. Patients in intermediate- or high-risk group who were transplanted with either unrelated CB or matched unrelated BM/mobilized PB in their CR1 were included in this study. The projected OS and EFS rates were 74.9% and 71.1%, respectively, with a median follow-up of 87.3 months after transplantation. The EFS was 70.1%, 80.7%, and 73.9% for CB, BM, and mobilized PB groups, respectively (P = 0.89), and 73.9% and 70.6% for IR and high-risk groups (P = 0.76). The leading cause of death was relapse (n = 8), and only one patient died from non-relapse cause. Unrelated donor HSCT seems a feasible approach for children with intermediate- or high-risk AML in CR1. Relapse remains the leading cause of treatment failure among these patients.

Patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation: trends in survival during the past two decades

It remains unclear how specific innovations in allogeneic hematopoietic cell transplantation (HCT) attained over the past decades have contributed to improvement in transplantation outcomes. To address this question, we conducted a registry-based study of adults with acute myeloid leukemia in first or second complete remission who underwent allogeneic HCT between 1994 and 2013 from a sibling (N = 1600) or unrelated (N = 2113) donor matched at the antigen level for HLA-A, -B, and -DR. Preliminary analysis led us to focus on comparisons between the 1994-2006 and 2007-2013 periods. Significant improvement in survival was observed in the later cohort compared to the earlier cohort for unrelated HCT (P = 0.004), but not for related HCT (P = 0.767). The improvement in unrelated HCT was solely due to diminished non-relapse mortality (P = 0.001), while incidence of relapse did not change over time (P = 0.934). The percentage of patients receiving transplants from 8/8-matched unrelated donors was significantly higher in the later cohort (P < 0.001), and their survival was significantly better than that of those undergoing mismatched unrelated HCT (P = 0.022). These findings suggest that advances in HLA-typing technology have been vital for improvement in transplantation outcomes.

Comparison of transplant outcomes and economic costs between biosimilar and originator filgrastim in allogeneic hematopoietic stem cell transplantation

From January 2012 to September 2015, 49 patients received biosimilar filgrastim (BF) after allogeneic bone marrow transplantation (BMT, n = 31) or peripheral stem cell transplantation (PBSCT, n = 18) in our institution. To evaluate the clinical impact of BF on transplant outcomes of these patients, we compared hematological recovery, overall survival (OS), disease-free survival (DFS), transplantation-related mortality (TRM), cumulative incidence of relapse (CIR), and acute and chronic graft-versus-host disease (GVHD) with those of control patients who received originator filgrastim (OF) after BMT (n = 31) or PBSCT (n = 18). All cases were randomly selected from a clinical database in our institution. In both the BMT and PBSCT settings, neutrophil recovery (17 vs. 19 days in BMT; 13 vs. 15 days in PBSCT) and platelet recovery (27 vs. 31 days in BMT; 17 vs. 28 days in PBSCT) were essentially the same between BF and OF. They were also comparable in terms of OS, DFS, TRM, CIR, and the incidence of acute GVHD and chronic GVHD. On multivariate analysis, the use of BF in both BMT and PBSCT was not a significant factor for adverse transplant outcomes. Although BF significantly reduced filgrastim costs in both BMT and PBSCT, total hospitalization costs were not significantly different between BF and OF.

TP53 mutations in older adults with acute myeloid leukemia

The net benefits of induction therapy for older adults with acute myeloid leukemia (AML) remain controversial. Because AML in older adults is a heterogeneous disease, it is important to identify those who are unlikely to benefit from induction therapy based on information available at the initial assessment. We used next-generation sequencing to analyze TP53 mutation status in AML patients aged 60 years or older, and evaluated its effects on outcomes. TP53 mutations were detected in 12 of 77 patients (16 %), and there was a significant association between TP53 mutations and monosomal karyotype. Patients with TP53 mutations had significantly worse survival than those without (P = 0.009), and multivariate analysis identified TP53 mutation status as the most significant prognostic factor for survival. Neverthelsess, TP53-mutated patients had a 42 % chance of complete remission and a median survival of 8.0 months, which compares favorably with those who did not undergo induction therapy, even in the short term. These results suggest that screening for TP53 mutations at diagnosis is useful for identifying older adults with AML who are least likely to respond to chemotherapy, although the presence of this mutation alone does not seem to justify rejecting induction therapy.

Efficacy of Allogeneic Hematopoietic Stem Cell Transplantation in Intermediate-Risk Acute Myeloid Leukemia Adult Patients in First Complete Remission: A Meta-Analysis of Prospective Studies

Hematopoietic stem cell transplantation (HSCT) and consolidation chemotherapy have been used to treat intermediate-risk acute myeloid leukemia (AML) patients in first complete remission (CR1). However, it is still unclear which treatments are most effective for these patients. The aim of our study was to analyze the relapse-free survival (RFS) and overall survival (OS) benefit of allogeneic HSCT (alloHSCT) for intermediate-risk AML patients in CR1. A meta-analysis of prospective trials comparing alloHSCT to non-alloHSCT (autologous HSCT [autoHSCT] and/or chemotherapy) was undertaken. We systematically searched PubMed, Embase, and the Cochrane Library though October 2014, using keywords and relative MeSH or Emtree terms, 'allogeneic'; 'acut*' and 'leukem*/aml/leukaem*/leucem*/leucaem*'; and 'nonlympho*' or 'myelo*'. A total of 7053 articles were accessed. The primary outcomes were RFS and OS, while the secondary outcomes were treatment-related mortality (TRM) and relapse rate (RR). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for each outcome. The primary outcomes were RFS and OS, while the secondary outcomes were TRM and RR. We included 9 prospective controlled studies including 1950 adult patients. Patients with intermediate-risk AML in CR1 who received either alloHSCT or non-alloHSCT were considered eligible. AlloHSCT was found to be associated with significantly better RFS, OS, and RR than non-alloHSCT (HR, 0.684 [95% CI: 0.48, 0.95]; HR, 0.76 [95% CI: 0.61, 0.95]; and HR, 0.58 [95% CI: 0.45, 0.75], respectively). TRM was significantly higher following alloHSCT than non-alloHSCT (HR, 3.09 [95% CI: 1.38, 6.92]). However, subgroup analysis showed no OS benefit for alloHSCT over autoHSCT (HR, 0.99 [95% CI: 0.70, 1.39]). In conclusion, alloHSCT is associated with more favorable RFS, OS, and RR benefits (but not TRM outcomes) than non-alloHSCT generally, but does not have an OS advantage over autoHSCT specifically, in patients with intermediate-risk AML in CR1.