Similar outcomes using myeloablative vs reduced-intensity allogeneic transplant preparative regimens for AML or MDS

Efficient bone marrow irradiation and low uptake by non-haematological organs with an yttrium-90-anti-CD66 antibody prior to haematopoietic stem cell transplantation

We report the results of a Phase I radiation dose escalation study using an yttrium-90 (90Y) labelled anti-CD66 monoclonal antibody given with standard conditioning regimen for patients receiving haematopoietic stem cell transplants for myeloid leukaemia or myeloma. The 90Y-labelled anti-CD66 was infused prior to standard conditioning. In total, 30 patients entered the trial and 29 received 90Y-labelled mAb, at infused radiation activity levels of 5, 10, 25, or 37.5 megaBequerel (MBq)/kg lean body weight. A prerequisite for receiving the 90Y-labelled mAb was favourable dosimetry determined by single-photon emission computerised tomography (SPECT) dosimetry following administration of indium-111 (111In) anti-CD66. Estimated absorbed radiation doses delivered to the red marrow demonstrated a linear relationship with the infused activity of 90Y-labelled mAb. At the highest activity level of 37.5 MBq/kg, mean estimated radiation doses for red marrow, liver, spleen, kidneys and lungs were 24.6 ± 5.6 Gy, 5.8 ± 2.7 Gy, 19.1 ± 8.0 Gy, 2.1 ± 1.1 and 2.2 ± 0.9, respectively. All patients engrafted, treatment-related mortality 1-year post-transplant was zero. Toxicities were no greater than those anticipated for similar conditioning regimens without targeted radiation. The ability to substantially intensify conditioning prior to haematopoietic stem cell transplantation without increasing toxicity warrants further testing to determine efficacy. clinicaltrials.gov identifier: NCT01521611.

Reduced intensity conditioning regimen of fludarabine, busulfan, ATG based haploidentical stem cell transplantation for older or unfit patients

Reduced-intensity conditioning (RIC) regimens allogeneic hematopoietic stem cell transplantation (HSCT) was developed for older patients or those with poor functional status. Haploidentical donor was appropriate alternative donor for patients without matched donors or patients with emergency disease state. However, there was few studies report the outcomes of RIC regimen of anti-thymocyte globulin (ATG) based haploidentical HSCT. The selection of the appropriate RIC regimen based on age and comorbidities in ATG-based haploidentical HSCT remains poorly described. To investigate the safety and efficacy of RIC regimen ATG-based haploidentical HSCT in older or unfit patients. Additionally, to explore the potential factors that impact the prognosis of RIC regimen of ATG-based haploidentical HSCT. We included a retrospective cohort of 63 patients with hematologic malignant diseases who underwent their first RIC haploidentical HSCT from November 2016 to June 2022 at our institutions. The conditioning regimen involved fludarabine (Flu) 30 mg/m²/kg 6 days combined with busulfan 3.2 mg/kg 2 days (Bu2) or 3 days (Bu3). ATG-Fresenius (ATG-F) was administered 10 mg/kg in total, ATG-thymoglobulin (ATG-T) was administered 6 mg/kg in total. The median age of patients in the entire cohort was 60 (32-67) years with a median follow-up of 496 (83-2182) days. There were 29 patients with AML, 20 patients with MDS, and 14 patients with ALL. A total of 32 patients underwent Bu2 RIC haplo-HSCT and 31 patients were treated with Bu3 RIC haplo-HSCT. The 2-year overall survival (OS) and 2-year disease-free survival (DFS) in whole cohort were 67.7% (95% confidence interval [CI], 53.8 - 85.1%) and 61.4% (95% CI, 48.8 - 77.3%) respectively. The cumulative incidence rates of grades II to IV and grades III to IV acute graft-versus-host disease (aGVHD) in whole cohort were 15.8% (95% CI, 4.8 - 19.6%) and 9.7% (95% CI, 0.0 - 11.8%) respectively. The 2-year cumulative incidence of chronic GVHD was 34.0% (95% CI, 18.9 - 46.3%). The 2-year cumulative incidence rates of relapse (IR) and non-relapse mortality (NRM) rates in whole cohort were 27.5% (95% CI, 14.5 - 33.7%) and 11.6% (95% CI, 2.2 - 21.9%) respectively. The probability of 2-year OS were 60.2% (95% CI:42.5-85.3%) in Bu2 and 85.5%(95% CI:73.0-100%) in Bu3 group respectively(P = 0.150). The probability of 2-year DFS were 49.7% (95% CI:33.0-74.8%) in Bu2 and 72.6% (95% CI:55.5-95.5%) in Bu3 group respectively (P = 0.045). The 2-year IR of Bu2 group was significantly higher than Bu3 group (P = 0.045). However, the 2-year NRM were not significantly different between Bu2 and Bu3 group(P > 0.05). In multivariable analysis, RIC regimen of Bu3 had superior OS and DFS than Bu2 group respectively [HR 0.42, 95% CI 0.18-0.98; P = 0.044; HR 0.34, 95% CI 0.14-0.86; P = 0.022]. Besides, RIC regimen of Bu3 had lower IR than Bu2 group [HR 0.34, 95% CI 0.13-0.89; P = 0.029]. The RIC regimen of ATG-based haploidentical HSCT is a safe and effective treatment option for patients who are older or have poor functional status. In particular, a relatively high-intensity pre-treatment regimen consisting of Bu achieves significant improvements in OS and DFS, thus providing more favorable post-transplantation clinical outcomes.

Advances in the management of higher-risk myelodysplastic syndromes: future prospects

Higher-risk myelodysplastic syndromes (HR-MDS) are defined using a number of prognostic scoring systems that include the degree of cytopenias, percentage of blasts, cytogenetic alterations, and more recently genomic data. HR-MDS encompasses characteristics such as progressive cytopenias, increased bone marrow blasts, unfavorable cytogenetics, and an adverse mutational profile. Survival is generally poor, and patients require therapy to improve outcomes. Hypomethylating agents (HMAs), such as azacitidine, decitabine, and more recently, oral decitabine/cedazuridine, are the only approved therapies for HR-MDS. These are often continued until loss of response, progression, or unacceptable toxicity. Combinations including an HMA plus other drugs have been investigated but have not demonstrated better outcomes compared to single-agent HMA. Moreover, in a disease of high genomic complexity such as HR-MDS, therapy targeting specific genomic abnormalities is of interest. This review will examine the biological underpinnings of HR-MDS, its therapeutic landscape in the frontline and relapsed settings, as well as the impact of hematopoietic stem cell transplantation, the only known curative intervention for this disease.

Allogeneic Stem Cell Transplantation in Refractory Acute Myeloid Leukaemia

Refractory acute myeloid leukaemia is very difficult to treat and represents an unmet clinical need. In recent years, new drugs and combinations of drugs have been tested in this category, with encouraging results. However, all treated patients relapsed and died from the disease. The only curative option is allogeneic transplantation through a graft from a healthy donor immune system. Using myeloablative conditioning regimens, the median overall survival regimens is 19%. Several so-called sequential induction chemotherapies followed by allogeneic transplantation conditioned by reduced intensity regimens have been developed, improving the overall survival to 25-57%. In the allogeneic transplantation field, continuous improvements in practices, particularly regarding graft versus host disease prevention, infection prevention, and treatment, have allowed us to observe improvements in survival rates. This is true mainly for patients in complete remission before transplantation and less so for refractory patients. However, full myeloablative regimens are toxic and carry a high risk of treatment-related mortality. In this review, we describe the results obtained with the different modalities used in more recent retrospective and prospective studies. Based on these findings, we speculate how allogeneic stem cell transplantation could be modified to maximise its therapeutic effect on refractory acute myeloid leukaemia.

CLAG combined with total body irradiation as intensive conditioning chemotherapy prior to allogeneic hematopoietic stem cell transplantation in patients with refractory or relapsed acute myeloid leukemia

Refractory or relapsed acute myeloid leukemia (R/R AML) remains the major challenge of AML treatment. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only valid option to achieve cure, but the prognosis is still dismal. We conducted a retrospective analysis for the feasibility of CLAG regimens (cladribine, cytarabine, and granulocyte colony-stimulating factor) combined with total body irradiation (TBI) as new intensive conditioning chemotherapy prior to HSCT in R/R AML. A total of 70 patients, including 21 primary refractory and 49 relapsed AML, were analyzed. Forty-nine (70%) patients had extramedullary diseases, and 54 (77%) patients received haploidentical transplantation. Except for one who died before white blood cell engraftment, all of the 69 evaluable patients achieved measurable residual disease (MRD) negative complete remission. The 3-year overall survival (OS) and relapse-free survival (RFS) rates were 46.0% (95% confidence interval [CI], 33.5-57.7%) and 38.5% (95%CI, 26.8-50.0%). The 1-year cumulative incidences of relapse and non-relapse mortality (NRM) were 38.6% (95%CI, 27.3-49.3%) and 11.6% (95%CI: 5.4-20.3%), respectively. The presence of chronic graft-versus-host disease (cGVHD) showed a trend to be associated with a lower risk of relapse (P = 0.054) and extramedullary diseases with a higher risk of NRM (P = 0.074). Multivariate analyses identified low leukemia burden pre-HSCT (defined as bone marrow blasts ≤ 50%) and cGVHD as independent factors associated with favorable OS and RFS. In conclusion, intensive conditioning with CLAG regimens plus TBI may be an effective and well-tolerated choice for R/R AML patients undergoing allo-HSCT.

MRD-directed and risk-adapted individualized stratified treatment of AML

Measurable residual disease (MRD) has been widely recognized as a biomarker for deeply evaluating complete remission (CR), predicting relapse, guiding pre-emptive interventions, and serving as an endpoint surrogate for drug testing. However, despite the emergence of new technologies, there remains a lack of comprehensive understanding regarding the proper techniques, sample materials, and optimal time points for MRD assessment. In this review, we summarized the MRD methods, sample sources, and evaluation frequency according to the risk category of the European Leukemia Net (ELN) 2022. Additionally, we emphasize the importance of properly utilizing and combining these technologies. We have also refined the flowchart outlining each time point for pre-emptive interventions and intervention paths. The evaluation of MRD in acute myeloid leukemia (AML) is sophisticated, clinically applicable, and technology-dependent, and necessitates standardized approaches and further research.

Novel risk assessment for the intensity of conditioning regimen in older patients

Reduced-intensity conditioning (RIC) regimens have long-term outcomes that are generally comparable with those of myeloablative conditioning (MAC) because of a lower risk of nonrelapse mortality (NRM) but a higher risk of relapse. However, it is unclear how we should select the conditioning intensity in individual cases. We propose the risk assessment for the intensity of conditioning regimen in elderly patients (RICE) score. We retrospectively analyzed 6147 recipients aged 50 to 69 years using a Japanese registry database. Based on the interaction analyses, advanced age (≥60 years), hematopoietic cell transplantation-specific comorbidity index (≥2), and umbilical cord blood were used to design a scoring system to predict the difference in an individual patient's risk of NRM between MAC and RIC: the RICE score, which is the sum of the 3 factors. Zero or 1 implies low RICE score and 2 or 3, high RICE score. In multivariate analyses, RIC was significantly associated with a decreased risk of NRM in patients with a high RICE score (training cohort: hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.60-0.90; P = .003; validation cohort: HR, 0.57; 95% CI, 0.43-0.77; P < .001). In contrast, we found no significant differences in NRM between MAC and RIC in patients with a low RICE score (training cohort: HR, 0.99; 95% CI, 0.85-1.15; P = .860; validation cohort: HR, 0.81; 95% CI, 0.66-1.01; P = .061). In summary, a new and simple scoring system, the RICE score, appears to be useful for personalizing the conditioning intensity and could improve transplant outcomes in older patients.

Comparison of reduced intensity and nonmyeloablative conditioning for adults with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation in first or second remission

Reduced intensity conditioning (RIC) and nonmyeloablative (NMA) conditioning regimens have expanded use of allogeneic hematopoietic cell transplantation (HCT) in AML to include older and medically less-fit patients, but relative efficacies and toxicities remain poorly defined. Here, we analyzed outcomes from 343 adults transplanted in remission after RIC (n = 137) or NMA (n = 206) conditioning between 2006 and 2021. The characteristics of RIC and NMA HCT patients were similar except that RIC patients were younger and their time between most recent remission achievement and allografting was shorter. There were no significant differences in relapse risk, relapse-free survival (RFS), overall survival (OS), and non-relapse mortality (NRM) between RIC and NMA HCT patients, both overall (relapse: hazard ratio [HR] = 0.80, P = 0.27; RFS: HR = 0.93, P = 0.61; OS: HR = 0.93, P = 0.66; NRM: HR = 1.13, P = 0.59) and when patients were stratified by pre-HCT measurable residual disease (MRD) status. After multivariable adjustment, there was no statistically significant association between conditioning intensity and relapse (HR = 0.69, P = 0.088), RFS (HR = 0.86, P = 0.37), OS (HR = 0.89, P = 0.49), or NRM (HR = 1.37, P = 0.19). In this non-randomized cohort of adults undergoing allografting for AML in first or second remission at our center, we could not detect statistically significant differences in outcomes between those assigned to RIC and those assigned to NMA conditioning.

Clofarabine and total body irradiation (TBI) as conditioning regimen for allogeneic stem cell transplantation in high-risk acute leukemia patients: a two-center retrospective cohort study

Clofarabine (Clo) is an immunosuppressive purine analog that may have better anti-leukemic activity than fludarabine (Flu). The addition of total body irradiation (TBI) to conditioning regimens has been widely investigated. However, the use of single agent Clo in combination with intermediate doses of TBI ranging from 4 to 8 Gy has not been studied yet. This study is a double center, observational, retrospective study of patients with high-risk hematological malignancies diagnosed from 2012 to 2021, treated at the American University of Beirut Medical Center in Beirut (AUBMC), Lebanon, and Saint-Antoine Hospital (SAH) in Paris, France. It aims to identify the outcome of patients with high-risk hematological malignancies who underwent allogeneic stem cell transplant (allo-SCT) and received Clo and TBI (4-8 Gy) before transplant. Data regarding patient baseline characteristics, disease-related factors, and transplant outcomes including graft-versus-host disease (GVHD), Non-relapse mortality (NRM), progression-free survival (PFS), and overall survival (OS), were collected. We identified 24 high-risk patients diagnosed with a hematological malignancy. The median age at transplant was 37 years (range 22-78). At the time of the transplant, only 15 patients (63%) were in complete remission (CR). All patients received Clo/TBI (4-8 Gy). After a median follow-up of 40 months, the cumulative incidences of grade II-III acute GVHD, grade IV acute GVHD, and chronic GVHD were 50%, 4%, and 8%, respectively. NRM at 100 days, and 1 year after transplant was 4% and 25%, respectively. 17% of the patients had a relapse or progression of the disease by the end of the study. The 2-year PFS and OS were 50% and 56%, respectively. The median PFS and OS were 66 and 68 months respectively. As a conclusion, Clo/TBI (4-8 Gy) as a conditioning regimen for allo-SCT in high-risk patients confers disease control with an acceptable toxicity profile.

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.

Clofarabine and Busulfan Myeloablative Conditioning in Allogeneic Hematopoietic Cell Transplantation for Patients With Active Myeloid Malignancies

Patients with refractory or relapsed and refractory myeloid malignancies have a poor prognosis. Allogeneic hematopoietic cell transplantation (HCT) with myeloablative conditioning (MAC) in patients with active, chemotherapy-refractory myeloid disease is historically associated with high rates of relapse and nonrelapse mortality (NRM). A MAC regimen combining clofarabine with busulfan (Clo/Bu4) has been reported to exhibit antileukemic activity with acceptable toxicity in patients age ≤70 years. Here we describe the clinical outcomes of a real-world population of patients with active myeloid malignancies undergoing allogeneic HCT with Clo/Bu4 MAC. In a single-center retrospective descriptive analysis, we identified patients who underwent HCT for myeloid malignancies not in remission using Clo/Bu4 MAC between 2012 and 2020. We report event-free survival (EFS) and overall survival (OS), cumulative incidences of relapse and NRM, and the incidence and severity of acute and chronic graft-versus-host disease (GVHD). We identified 69 patients with a median age of 60 years (range, 22 to 70 years). Most patients had relapsed/refractory or primary refractory acute myelogenous leukemia (AML; n = 55) or refractory myelodysplastic syndrome (MDS; n = 12); 1 patient had chronic myelogenous leukemia, and 1 patient had a blastic plasmacytoid dendritic cell neoplasm. Fifty patients (72.5%) had complete remission at day 100 post-transplantation. Two-year EFS and OS were 30% (95% confidence interval [CI], 20% to 44%) and 40% (95% CI, 29% to 54%), respectively. Patients with AML had a 2-year EFS and OS of 28% (95% CI, 18% to 44%) and 38% (95% CI, 27% to 54%), respectively; those with MDS had a 2-year EFS and OS of 47% (95% CI, 25% to 88%) and 56% (95% CI, 33% to 94%), respectively. The cumulative incidence of relapse at 2 years was 39% (95% CI, 27% to 51%) for all patients, including 45% (95% CI, 31% to 58%) in the patients with AML and 18% (95% CI, 2% to 45%) in those with MDS. NRM at 2 years was 31% (95% CI, 20% to 42%), including 27% (95% CI, 15% to 39%) in patients with AML and 35% (95% CI, 10% to 63%) in those with MDS. The total incidence of acute GVHD (aGVHD) of any severity was 80%, and the incidence of grade III-IV aGVHD was 22%. In patients who achieved remission, those who required systemic immunosuppression for aGVHD (58%) had poorer 2-year EFS (29% versus 54%; P = .05) and 2-year OS (39% versus 70%; P = .04) compared to those who did not. The 2-year cumulative incidence of chronic GVHD was 44% (95% CI, 28% to 58%). Clo/Bu4 MAC followed by allogeneic HCT for patients with active myeloid malignancies is an effective transplantation strategy for patients up to age 70, particularly those with advanced MDS. The high incidence of and poor outcomes associated with aGVHD highlight the importance of optimizing preventative strategies.

Clinical Experience of Allogeneic Hematopoietic Stem Cell Transplantation in Elderly Patients Aged 60 Years and Older in South Korea

PURPOSE

The purpose of this study is to share our outcomes and experiences on allogeneic hematopoietic stem cell transplantation (HSCT) in elderly patients aged 60 years and older with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) in South Korea, and to compare them with other studies.

MATERIALS AND METHODS

We analyzed the clinical outcomes of 116 patients with AML or MDS aged 60 years and older who underwent allogeneic HSCT. We also analyzed which pretreatment factors affect the overall survival (OS) after allogeneic HSCT.

RESULTS

Neutrophil and platelet engraftment were achieved at median day +11 [interquartile range (IQR) 10-15] and +14 (IQR 11-19), respectively. A complete donor chimerism was confirmed in 65 (56.0%) patients at 3 weeks and in 63 (54.3%) patients at 3 months after HSCT. The estimated incidence of grade II-IV acute graft-versus-host disease (GVHD) at day 100 was 13.7%. The estimated incidence of chronic GVHD at 2 years was 38.8%. Within a median follow-up of 14 months after HSCT, OS was 64% at 1 year and 55% at 2 years, and non-relapse mortality (NRM) was 20% at 1 year and 28% at 2 years. Multivariate analysis revealed that male sex and Hematopoietic Cell Transplantation-Specific Comorbidity Index ≥3 were associated with poor OS.

CONCLUSION

This study showed that allogeneic HSCT in elderly adults aged 60 and older can be performed with successful engraftment and acceptable NRM and OS are expected given the generally known survival of patients with higher risk MDS and poor risk AML.

Hematopoietic Cell Transplantation in the Management of Myelodysplastic Syndrome: An Evidence-Based Review from the American Society for Transplantation and Cellular Therapy Committee on Practice Guidelines

The sole curative therapy for myelodysplastic syndrome (MDS) is allogeneic hematopoietic cell transplantation (HCT). Here this therapeutic modality is reviewed and critically evaluated in the context of the evidence. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the recommendations. A panel of MDS experts comprising transplantation and nontransplantation physicians developed consensus treatment recommendations. This review summarizes the standard MDS indications for HCT and addresses areas of controversy. Recent prospective trials have confirmed that allogeneic HCT confers survival benefits in patients with advanced or high-risk MDS compared with nontransplantation approaches, and the use of HCT is increasing in older patients with good performance status. However, patients with high-risk cytogenetic or molecular mutations remain at high risk for relapse. It is unknown whether administration of novel therapies before or after transplantation may decrease the risk of disease relapse in selected populations. Ongoing and future studies will investigate revised approaches to disease risk stratification, patient selection, and post-transplantation approaches to optimize allogeneic HCT outcomes for patients with MDS.

Intensified conditioning regimens improved disease-free survival and engraftment after unrelated single-unit cord blood transplantation but not after matched sibling or matched unrelated donor allogeneic hematopoietic cell transplantation

The impact of conditioning intensity on different donor groups has been unclear in allogeneic transplantation. The objective of this study was to clarify the effect of conditioning intensity on disease-free survival (DFS), relapse, non-relapse mortality (NRM), neutrophil engraftment, and graft-versus-host disease for each donor type. We retrospectively evaluated the effect of conditioning intensity on transplant outcomes for patients with acute leukemia or myelodysplastic syndrome aged between 16 and 60 years in Japan using the transplant conditioning intensity (TCI) scoring system. A total of 8526 patients who received first allogeneic transplantation from 6/6 antigen-matched sibling donor (MSD, n = 2768), 8/8 allele-matched unrelated donor (MUD, n = 2357), and unrelated single-cord blood (UCB, n = 3401) were eligible for the analyses. Compared to conditioning with TCI score 4.0, which was corresponds to conventional myeloablative conditioning, including cyclophosphamide with total body irradiation 12 Gy or busulfan 12.8 mg, and was considered as the reference group in the multivariate analyses, intensified conditioning with TCI score ≥4.5 improved DFS (hazard ratio [HR],0.81, P < 0.001) and relapse rate (HR, 0.70, P < 0.001) but only after UCB transplants and not MSD and MUD transplants. In contrast, NRM was higher after intensified conditioning with TCI score ≥4.5 for MSD (HR, 1.39, P = 0.008) and MUD (HR, 1.47, P = 0.002) transplants but not UCB transplants (HR, 1.12, P = 0.240). Neutrophil engraftment was also significantly higher after intensified conditioning with TCI score ≥4.5 but only for UCB transplants (HR, 1.24, P < 0.001), whereas it was significantly lower after reduced-intensity conditioning with TCI score ≤3.5 for MSD transplants only (HR, 0.82, P < 0.001). These data demonstrated that an intensified conditioning regimen improved survival and engraftment rate only after a UCB transplants. Therefore, TCI scoring system could enable the optimization of conditioning intensity according to donor type, particularly in terms of survival and engraftment.

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.

Efficacy of decitabine combined with allogeneic hematopoietic stem cell transplantation in the treatment of recurrent and refractory acute myeloid leukemia (AML): A systematic review and meta-analysis

BACKGROUND

This analysis aimed to assess the effect of decitabine combined with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in treating recurrent and refractory acute myeloid leukemia.

METHOD

The present analysis was carried out according to the principles of Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline statement. Web of Science, Embase, PubMed, The Cochrane Library, CNKI, VIP, and WanFang Data databases were searched for trials published from their corresponding inception to September 13, 2021. Retrospective research or published randomized controlled trials in Chinese or English were ruled out. The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database scale. Mean differences with 95% confidence intervals were used to analyze continuous data. The I2 test was used to determine heterogeneity, and the meta-analysis was conducted using Revman 5.4.

RESULTS

Eight studies including 795 participants in total were identified. Decitabine and allo-HSCT showed significant reductions in recurrence after transplantation (odds ratio [OR] = 0.29, 95% confidence interval [CI] (0.17, 0.50), P < .00001), leukemia-free survival (OR = 2.17, 95% CI (1.47, 3.21), P < .0001), graft related death (OR = 0.50, 95% CI (0.25, 0.98), P = .04), and significant improvements in complete remission (OR = 0.39, 95% CI = 0.23-0.68, P = .0007) and partial remission (OR = 0.46, 95%CI = 0.27-0.78, P = .004). The median follow-up time, acute graft-versus-host disease, and no remission had no significant difference between treatment and control groups (the median follow-up time: OR = -1.76, 95% CI (-6.28, 2.76), P = .45; acute graft-versus-host disease: OR = 0.72, 95% CI (0.50, 1.03), P = .08; no remission: OR = 3.19, 95%CI = 2.06-4.94, P = .05). Overall, the magnitude of the effect was found to be in the small to moderate range.

CONCLUSION

Decitabine combined with allo-HSCT can obtain lower recurrence risk and longer disease-free survival time, and improve the prognosis of patients. The safety is relatively stable. Due to the varying quality level of the included studies, the validation of multiple high-quality studies still needs improvement.

Augmented FLAMSA-Bu versus FluBu2 reduced-intensity conditioning in patients with active relapsed/refractory acute myeloid leukemia: an EBMT analysis

Comparative data of fludarabine, cytarabine and amsacrine (FLAMSA) chemotherapy followed by busulfan (Bu)-based reduced-intensity conditioning (RIC) (FLAMSA-Bu) versus RIC regimens are lacking in patients with active relapsed/refractory (R/R) acute myeloid leukemia (AML) at the time of allogeneic hematopoietic stem cell transplantation (alloSCT). Here, we retrospectively analyzed outcomes after FLAMSA-Bu versus fludarabine/busulfan (FluBu2) conditioning in this patient population. A total of 476 patients fulfilled the inclusion criteria, of whom 257 received FluBu2 and 219 FLAMSA-Bu. Median follow-up was 41 months. Two-year non-relapse mortality (21%), graft-versus-host disease-free, relapse-free survival (24%) and chronic graft-versus-host disease (GVHD) (29%) were not statistically different between cohorts. FLAMSA-Bu was associated with lower 2-year relapse incidence (RI) (38 vs 49% after FluBu2, p = 0.004), and increased leukemia-free survival (LFS) (42 vs 29%, p = 0.001), overall survival (47 vs 39%, p = 0.008) and grades II-IV acute GVHD (36 vs 20%, p = 0.001). In the multivariate analysis, FLAMSA-Bu remained associated with lower RI (HR 0.69, p = 0.042), increased LFS (HR 0.74, p = 0.048) and a higher risk of acute GVHD (HR 2.06, p = 0.005). Notwithstanding the limitations inherent in this analysis, our data indicate that FLAMSA-Bu constitutes a tolerable conditioning strategy, resulting in a long-term benefit in a subset of patients reaching alloSCT with active disease.

BMT for Myelodysplastic Syndrome: When and Where and How

Myelodysplastic syndromes (MDS) are a diverse group of hematological malignancies distinguished by a combination of dysplasia in the bone marrow, cytopenias and the risk of leukemic transformation. The hallmark of MDS is bone marrow failure which occurs due to selective growth of somatically mutated clonal hematopoietic stem cells. Multiple prognostic models have been developed to help predict survival and leukemic transformation, including the international prognostic scoring system (IPSS), revised international prognostic scoring system (IPSS-R), WHO prognostic scoring system (WPSS) and MD Anderson prognostic scoring system (MDAPSS). This risk stratification informs management as low risk (LR)-MDS treatment focuses on improving quality of life and cytopenias, while the treatment of high risk (HR)-MDS focuses on delaying disease progression and improving survival. While therapies such as erythropoiesis stimulating agents (ESAs), erythroid maturation agents (EMAs), immunomodulatory imide drugs (IMIDs), and hypomethylating agents (HMAs) may provide benefit, allogeneic blood or marrow transplant (alloBMT) is the only treatment that can offer cure for MDS. However, this therapy is marred, historically, by high rates of toxicity and transplant related mortality (TRM). Because of this, alloBMT is considered in a minority of MDS patients. With modern techniques, alloBMT has become a suitable option even for patients of advanced age or with significant comorbidities, many of whom who would not have been considered for transplant in prior years. Hence, a formal transplant evaluation to weigh the complex balance of patient and disease related factors and determine the potential benefit of transplant should be considered early in the disease course for most MDS patients. Once alloBMT is recommended, timing is a crucial consideration since delaying transplant can lead to disease progression and development of other comorbidities that may preclude transplant. Despite the success of alloBMT, relapse remains a major barrier to success and novel approaches are necessary to mitigate this risk and improve long term cure rates. This review describes various factors that should be considered when choosing patients with MDS who should pursue transplant, approaches and timing of transplant, and future directions of the field.

Incidence and Outcomes of Respiratory Failure After Non-Myeloablative Related Haploidentical Blood or Marrow Transplant

BACKGROUND

Respiratory failure is a devastating complication of allogenic blood or marrow transplant (BMT). Prior data suggest 20% and 15% of BMT patients develop respiratory failure and ARDS, respectively. Non-myeloablative (NMA) haploidentical BMT allows donor pool expansion and may decrease complications. Incidence, outcomes, and risk factors for respiratory failure after NMA haploidentical BMT are unknown.

RESEARCH QUESTION

Determine the incidence of respiratory failure after NMA haploidentical BMT and explore outcomes and risk factors for respiratory failure.

STUDY DESIGN AND METHODS

Single-center, retrospective study of all patients > 18 years old undergoing NMA haploidentical BMT from 2004-2016. The primary outcome was respiratory failure (high-flow nasal cannula oxygen, non-invasive ventilation [NIV], or invasive mechanical ventilation [IMV]) within 2 years after BMT. Respiratory failure incidence is reported as incidence rate ratios (IRR) with 95% confidence intervals. Unadjusted and multivariable Cox proportional hazards models with adjustment for a priori identified patient-level characteristics were used. Results are presented as hazard ratios (HR) with 95% CIs.

RESULTS

520 patients underwent NMA haploidentical BMT; 82 (15.8%) developed respiratory failure (IRR 0.114/person-year) at a median of 0.34 years (25^th, 75^th percentiles 0.06, 0.75 years) after BMT. Older age (HR 1.04, 1.02, 1.07), transplant for MDS (HR 1.99, 1.07, 3.72), and parent donor (HR 3.49, 1.32, 9.26) were associated with increased risk of respiratory failure; higher pre-transplant DLCO (% pred) was associated with lower risk (HR 0.98, 0.77, 0.99). Sixty-one (11.7%) patients required IMV; 30 were successfully extubated. Only 37 (7%) patients had ARDS. Of the 82 with respiratory failure, 43 (52.4%) and 61 (77.2%) died during index hospitalization and by 2 years, respectively. Only 40 (49%) had non-relapse mortality.

INTERPRETATION

Incidence of respiratory failure and ARDS after NMA haploidentical BMT is modest at 15% by 2 years after transplant. Despite successful extubation in more than 50% of patients, respiratory failure, regardless of cause, is associated with a high rate of death by 2 years, from both relapse and non-relapse causes. Age, BMT for MDS, parental donor, and pre-transplant DLCO were risk factors for respiratory failure.

Effective Immunosurveillance After Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemia

The number of patients receiving allogeneic hematopoietic stem cell transplantation (alloHCT) has increased constantly over the last years due to advances in transplant technology development, supportive care, transplant safety, and donor availability. Currently, acute myeloid leukemia (AML) is the most frequent indication for alloHCT. However, disease relapse remains the main cause of therapy failure. Therefore, concepts of maintaining and, if necessary, reinforcing a strong graft-versus-leukemia (GvL) effect is crucial for the prognosis and long-term survival of the patients. Over the last decades, it has become evident that effective immunosurveillance after alloHCT is an entangled complex of donor-specific characteristics, leukemia-associated geno- and phenotypes, and acquired resistance mechanisms. Furthermore, adoption of effector cells such as natural killer (NK) cells, alloreactive and regulatory T-cells with their accompanying receptor repertoire, and cell–cell interactions driven by messenger molecules within the stem cell and the bone marrow niche have important impact. In this review of pre- and posttransplant elements and mechanisms of immunosurveillance, we highlight the most important mechanisms after alloHCT.

Allogeneic hematopoietic cell transplantation in patients with myelodysplastic syndrome using treosulfan based compared to other reduced-intensity or myeloablative conditioning regimens. A report of the chronic malignancies working party of the EBMT

Allogeneic haematopoietic-cell transplantation (allo-HCT) is a potentially curative therapy for high-risk myelodysplastic syndrome (MDS). Reduced-intensity conditioning (RIC) is usually associated with lower non-relapse mortality (NRM), higher relapse rate and similar overall-survival (OS) as myeloablative-conditioning (MAC). Fludarabine/treosulfan (FT) is a reduced-toxicity regimen with intense anti-leukaemia activity and a favourable toxicity profile. We investigated post-transplant outcomes in 1722 MDS patients following allo-HCT with FT (n = 367), RIC (n = 687) or MAC (n = 668). FT and RIC recipients were older than MAC recipients, median age 59, 59 and 51 years, respectively (P < 0·001) but other disease characteristics were similar. The median follow-up was 64 months (1-171). Five-year relapse rates were 25% (21-30), 38% (34-42) and 25% (22-29), after FT, RIC and MAC, respectively, (P < 0·001). NRM was 30% (25-35), 27% (23-30) and 34% (31-38, P = 0·008), respectively. Five-year OS was 50% (44-55), 43% (38-47), and 43% (39-47), respectively (P = 0·03). In multivariate analysis, FT was associated with a lower risk of relapse (HR 0·55, P < 0·001) and better OS (HR 0·72, P = 0·01). MAC was associated with higher NRM (HR 1·44, P = 0·001). In conclusion, FT is associated with similar low relapse rates as MAC and similar low NRM as RIC, resulting in improved OS. FT may be the preferred regimen for allo-HCT in MDS.

Immunotherapy in hematological malignancies: recent advances and open questions

Over recent years, tremendous advances in immunotherapy approaches have been observed, generating significant clinical progress. Cancer immunotherapy has been shown, in different types of blood cancers, to improve the overall survival of patients. Immunotherapy treatment of hematopoietic malignancies is a newly growing field that has been accelerating over the past years. Several US FDA approved drugs and cell-based therapies are being exploited in the late stage of clinical trials. This review attempt to highlight and discuss the numerous innovative immunotherapy approaches of hematopoietic malignancy ranging from nonmyeloablative transplantation, T-cell immunotherapy, natural killer cells and immune agonist to monoclonal antibodies and vaccination. In addition, a brief discussion on the future advances and accomplishments required to counterpart the current immunotherapeutic approaches for hematopoietic malignancies were also highlighted.

On Behalf of the SFGM-TC: Retrospective Comparison of Reduced and Higher Intensity Conditioning for High-Risk Myelodysplastic Syndrome Treated With Allogeneic Stem-Cell Transplantation

BACKGROUND

Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) remains the best curative option for high-risk myelodysplastic syndrome . We retrospectively compared patient outcomes after allo-HSCT according to the intensity of the conditioning regimen.

PATIENTS AND METHODS

Three conditioning regimens were compared in 427 patients allografted for high-risk myelodysplastic syndrome: reduced-intensity conditioning (RIC), fludarabine (150-160 mg/m²) and busulfan (6.4 mg/kg); sequential FLAMSA-RIC, fludarabine, amsacrine, and aracytine followed by RIC; and myeloablative with reduced toxicity (RTC), fludarabine and busulfan (9.6 mg/kg or 12.8 mg/kg).

RESULTS

The patients in the 3 conditioning groups were different in regards to the number of treatment lines (P< .001), percentage of blasts in bone marrow (P< .001), and disease status at transplantation (P< .001). No significant differences in outcomes (overall survival, progression-free survival, nonrelapse mortality, relapse incidence, and graft versus host disease relapse-free survival) were observed between the 3 groups. Using propensity score analysis to overcome baseline imbalances, we compared 70 patients receiving FLAMSA-RIC to 260 patients receiving RIC, and compared 83 patients receiving RTC to 252 patients receiving RIC. The only factor influencing overall and progression-free survival was cytogenetic risk at transplantation. After the covariate adjustment using propensity score to reduce baseline imbalances, the only factor influencing overall and progression-free survival was still cytogenetic risk at transplantation.

CONCLUSION

Overall survival appears to be similar with the 3 conditioning regimens. The only factor influencing survival is cytogenetic risk at transplantation, suggesting that new promising drugs in the conditioning and/or early interventions after transplantation are needed to improve outcomes in these patients.

Impact of induction chemotherapy with intermediate-dosed cytarabine and subsequent allogeneic stem cell transplantation on the outcome of high-risk acute myeloid leukemia

Background

Acute myeloid leukemia (AML) with antecedent hematological disease (s-AML) and treatment-related AML (t-AML) predicts poor prognosis. Intensive treatment protocols of those high-risk patients should consider allogeneic stem cell transplantation (allo-HSCT) in first complete remission (CR). Despite allo-HSCT, relapse rate remains high. Induction chemotherapy with liposomal cytarabine and daunorubicin (CPX-351) has been approved for patients with AML with myeloid-related changes (AML-MRC) or t-AML based on improved survival and remission rates compared to standard 7 + 3 induction.

Patients and methods

110 patients with newly diagnosed s-AML or t-AML at a university hospital were analyzed retrospectively. Median age was 62 years (24–77 years). A total of 65 patients with s-AML after MDS (59%) and 23 patients (20.9%) with t-AML were included. Induction chemotherapy consisted of intermediate-dosed cytarabine (ID-AraC) in combination with idarubicin (patients up to 60 years) or mitoxantrone (patients over 60 years). In patients subsequently undergoing allo-HSCT, reduced conditioning regimens (RIC) were applied prior to transplantation in 47 of 62 patients (76%).

Results

Induction chemotherapy with ID-AraC resulted in an overall response rate of 83% including complete remission (CR/CRi) in 69 patients (63%) with a low rate of early death (2.7%). Most relevant non-hematologic toxicity consisted of infectious complications including sepsis with need of intensive care treatment in five patients (4.5%) and proven or probable invasive fungal disease in eight patients (7.2%). Relapse-free survival (RFS), event-free survival (EFS) and overall survival (OS) of the whole cohort were 19 months (0–167), 10 months (0–234) and 15 months (0–234), respectively (p < 0.0001). A significant improvement of OS was observed in patients who underwent allo-HSCT compared to those without subsequent allo-HSCT: 9 vs. 46 months, p < 0.0001. Rate of transplantation-related mortality (TRM) in the early phase post allo-HSCT was low (0.9% at day 30 and 1.8% at day 90, respectively). RIC conditioning results in OS rate of 60% after 60 months post allo-HSCT (median OS not reached).

Conclusion

S-AML and t-AML patients receiving induction chemotherapy with intermediate-dosed cytarabine showed satisfactory response rate and consolidation therapy with allo-HSCT after full or reduced-intensity conditioning further improved survival in these patients with similar outcome as reported for CPX-351.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03733-0.

Dose intensity for conditioning in allogeneic hematopoietic cell transplantation: can we recommend "when and for whom" in 2021?

Allogeneic hematopoietic stem-cell transplantation is a potentially curative therapy for various hematologic diseases. An essential component of this procedure is the pre-transplant conditioning regimen, which should facilitate engraftment and reduce or eliminate tumor cells. The recognition of the substantial association of a graft-versus- tumor effect and the high toxicity of the commonly used conditioning regimen led to the introduction of more differentiated intensity strategies, with the aim of making hematopoietic stem-cell transplantation less toxic and safer, and thus more applicable to broader populations such as older or unfit patients. In general, prospective and retrospective studies suggest a correlation between increasing intensity and nonrelapse mortality and an inverse correlation with relapse incidence. In this review, we will summarize traditional and updated definitions for conditioning intensity strategies and the landscape of comparative prospective and retrospective studies, which may help to find the balance between the risk of non-relapse mortality and relapse. We will try to underscore the caveats regarding these definitions and analyses, by missing complex differences between intensity and toxicity as well as the broad influences of other factors in the transplantation procedure. We will summarize evidence regarding several confounders which may influence decisions when selecting the intensity of the conditioning regimen for any given patient, according to the individual risk of relapse and non-relapse mortality.

Novel Indicators of Transplant Outcomes for PhALL: Current Molecular-Relapse-Free Survival

Molecular relapse after allogeneic hematopoietic cell transplantation (allo-HCT) has been thought to predict clinical relapse in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (PhALL). Tyrosine kinase inhibitor (TKI) administration after allo-HCT may dynamically change the status from molecular relapse to molecular remission, but these state changes cannot be accurately represented by conventional survival indicators such as relapse-free survival, where events are usually considered irreversible. We aimed to develop novel indicators of transplant outcomes for allo-HCT recipients with PhALL and to visualize current molecular-relapse-free survival (CMRFS) and current on-TKI status (CTKI), treating molecular relapse or TKI administration after allo-HCT as a reversible event. We retrospectively analyzed 286 patients with PhALL who received allo-HCT between 2000 and 2016 in order to develop the indicators. CMRFS was defined as the probability of molecular remission without clinical relapse or death at any time after allo-HCT. Similarly, CTKI was defined as the probability of TKI administration without clinical relapse or death at any time after allo-HCT. The 1- and 5-year CMRFS rates were 67% and 59%, respectively, whereas the 1- and 5-year conventional molecular relapse-free survival rates were 42% and 37%. The 1- and 5-year CTKI rates were 14% and 8%, respectively. In a post hoc analysis focusing on patients who had achieved a molecular complete remission within 6 weeks (n = 201), the 5-year CMRFS rate (71%) was similar to the 5-year conventional molecular relapse-free survival (molRFS) rate (70%) in the non-TKI group. On the other hand, the 5-year CMRFS rate in the TKI group was 61%, whereas the 5-year conventional molRFS rate was only 38%. CMRFS and CTKI might become useful indicators of transplant success in terms of survival, leukemia-free status, and treatment-free status at any time point. Future extension of these survival models to other clinical situations is warranted.

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 intensity conditioning for acute myeloid leukemia using melphalan- vs busulfan-based regimens: a CIBMTR report

There is a lack of large comparative study on the outcomes of reduced intensity conditioning (RIC) in acute myeloid leukemia (AML) transplantation using fludarabine/busulfan (FB) and fludarabine/melphalan (FM) regimens. Adult AML patients from Center for International Blood and Marrow Transplant Research who received first RIC allo-transplant between 2001 and 2015 were studied. Patients were excluded if they received cord blood or identical twin transplant, total body irradiation in conditioning, or graft-versus-host disease (GVHD) prophylaxis with in vitro T-cell depletion. Primary outcome was overall survival (OS), secondary end points were leukemia-free survival (LFS), nonrelapse mortality (NRM), relapse, and GVHD. Multivariate survival model was used with adjustment for patient, leukemia, and transplant-related factors. A total of 622 patients received FM and 791 received FB RIC. Compared with FB, the FM group had fewer transplant in complete remission (CR), fewer matched sibling donors, and less usage of anti-thymocyte globulin or alemtuzumab. More patients in the FM group received marrow grafts and had transplantation before 2005. OS was significantly lower within the first 3 months posttransplant in the FM group (hazard ratio [HR] = 1.82, P < .001), but was marginally superior beyond 3 months (HR = 0.87, P = .05). LFS was better with FM compared with FB (HR = 0.89, P = .05). NRM was significantly increased in the FM group during the first 3 months of posttransplant (HR = 3.85, P < .001). Long-term relapse was lower with FM (HR = 0.65, P < .001). Analysis restricted to patients with CR showed comparable results. In conclusion, compared with FB, the FM RIC showed a marginally superior long-term OS and LFS and a lower relapse rate. A lower OS early posttransplant within 3 months was largely the result of a higher early NRM.

Comparison of Myeloablative versus Reduced-Intensity Conditioning Regimens in Allogeneic Stem Cell Transplantation Recipients with Acute Myelogenous Leukemia with Measurable Residual Disease-Negative Disease at the Time of Transplantation: A Retrospective Cohort Study

The ideal conditioning intensity in allogeneic hematopoietic stem cell transplantation (HSCT) is evolving. Previous prospective studies comparing myeloablative conditioning (MAC) versus reduced-intensity conditioning (RIC) regimens in adults with acute myelogenous leukemia (AML) have shown mixed results. In many of these studies, patients were not stratified based on measurable residual disease (MRD). We evaluated the effect of conditioning intensity on the outcomes of AML patients in complete remission (CR) with flow cytometry evidence of MRD negativity. A total of 135 patients age 20 to 75 years with AML in CR1 or CR2 and flow cytometry evidence of MRD negativity who underwent allogeneic HSCT at our center between 2011 and 2019 were evaluated. We compared overall survival (OS), relapse-free survival (RFS), nonrelapse mortality (NRM), relapse, and acute and chronic graft-versus-host disease (GVHD) in recipients of MAC (n = 89) and RIC (n = 46). Although the patients receiving RIC were older (62 versus 51 years; P < .0001), there were no statistically significant differences between the groups in terms of Eastern Cooperative Oncology Group and European Leukemia Network risk criteria and disease status (CR1 or CR2) at the time of transplantation. At a median follow-up of 24.6 months, no statistically significant differences in OS (hazard ratio [HR], 0.78; 95% confidence interval [CI] 0.42 to 1.42, P = .411) or RFS (HR, 1.004; 95% CI, 0.48 to 2.09, P = .99) were identified. The cumulative incidence of NRM (HR, 0.595; 95% CI, 0.24 to 1.48; P = .2644) and relapse (HR, 1.007; 95% CI, 0.45 to 2.23; P = .9872) was not different between the 2 groups. Grade II-IV and grade III-IV acute GVHD were more frequent in the MAC group (39.3% verses 19.9% [P = .018] and 19.3% versus 2.3% [P < .001], respectively), as was moderate/severe chronic GVHD (23.6% versus 15.8%; P = .038). Our data indicate that conditioning intensity did not appear to affect OS, RFS, NRM, and relapse risk in patients with MRD-negative AML as measured by flow cytometry. RIC resulted in less severe acute and chronic GVHD.

Should patients receive consolidation chemotherapy before reduced intensity allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia in first complete remission?

Background:

For acute myeloid leukemia (AML) patients, the role of bridging consolidation chemotherapy after achieving first complete remission (CR1) in the transplant setting is a frequently debated issue. The lack of data from Asian patients led us to conduct this study.

Methods:

We retrospectively studied outcomes of 106 patients in CR1 undergoing allogeneic stem cell transplantation (alloSCT) with reduced intensity conditioning (RIC) based on their exposure to pre-transplant consolidation chemotherapy. There were 35 in the no consolidation group versus 71 in the consolidation group.

Results:

The median relapse free survival (RFS) was 9 months for the no consolidation group and 51 months for consolidation group (p = 0.023). The median overall survival was 32 months for the no consolidation group and not reached for the consolidation group (p = 0.034). Multivariate analysis recognized consolidation and poor cytogenetics as adverse prognostic factors for RFS. Moreover, RFS was better in patients with a shorter time lapse between last chemotherapy and alloSCT in both the no consolidation group and the consolidation group. Consolidation chemotherapy did not negatively affect neutrophil and platelet engraftment, infection rates, or acute graft-versus-host disease (GVHD) incidence. On the other hand, patients undergoing consolidation chemotherapy showed trends towards a more severe degree of chronic GVHD.

Conclusion:

The exposure to consolidation chemotherapy in CR1 prior to alloSCT with RIC conditioning did not negatively impact the outcomes in Korean AML patients, for whom a suitable donor is rarely immediately available. Therefore, post-remission consolidation chemotherapy is a reasonable option if required.

Measurable residual disease as a biomarker in acute myeloid leukemia: theoretical and practical considerations

Several methodologies that rely on the detection of immunophenotypic or molecular abnormalities of the neoplastic cells are now available to quantify measurable ("minimal") residual disease (MRD) in acute myeloid leukemia (AML). Although the perfect MRD test does not (yet) exist, the strong association between MRD and adverse patient outcomes has provided the impetus to use measures of MRD as biomarker in the routine care of AML patients and during clinical trials. MRD test results may inform the selection of postremission therapy in some patients but evidence supporting the use of MRD as predictive biomarker is still limited. Several retrospective studies have shown that conversion from undetectable to detectable MRD or increasing MRD over time is associated with overt disease recurrence, and MRD testing may therefore be valuable as a monitoring biomarker for early detection of relapse. Interpreting serial MRD data is complex, with open questions regarding the optimal timing and frequency of testing, as well as the identification of test-specific thresholds to define relapse. Importantly, it is unknown whether intervening at the time of MRD detection, rather than at overt disease recurrence, improves outcomes. Finally, using MRD as a surrogate efficacy-response biomarker to accelerate drug development/approval has already been accepted by regulatory authorities in other diseases and is of great interest as a potential strategy in AML. While the prognostic value of MRD in AML is well established, data from prospective clinical trials confirming that treatment effects on MRD directly relate to clinical outcomes are needed to further establish the role of MRD as a surrogate endpoint in AML.

Myeloablative versus Reduced-Intensity Conditioning for Hematopoietic Cell Transplantation in Acute Myelogenous Leukemia and Myelodysplastic Syndromes-Long-Term Follow-Up of the BMT CTN 0901 Clinical Trial

Several prospective randomized trials comparing conditioning intensity before allogeneic hematopoietic cell transplantation (HCT) have been performed, with conflicting results. Although reduced-intensity conditioning (RIC) leads to lower treatment-related mortality (TRM), this is offset by higher rates of relapse. Long-term follow-up of randomized comparative trials are limited. Here we present long-term follow-up of a randomized comparison of myeloablative conditioning (MAC) compared with RIC before HCT for acute myelogenous leukemia (AML) or myelodysplasia (MDS). Long-term comparative analyses of overall survival, relapse, and relapse-free survival were performed. Patients age 18 to 65 years with <5% marrow myeloblasts were randomized to receive MAC (n = 135) or RIC (n = 137), followed by HCT from an HLA-matched donor. The primary endpoint of the trial was an 18-month pointwise comparison of overall survival. The analyses were performed using a proportional hazards model. The median follow-up of the entire cohort was 51 months. At 4 years, the transplant-related mortality (TRM) was 25.1% for MAC, compared with 9.9% for RIC (P < .001). Patients who received RIC had a significantly higher risk of relapse compared to those who received MAC (hazard ratio [HR], 4.06; 95% CI, 2.59 to 6.35; P < 0.001). Among the patients who relapsed after HCT, postrelapse survival was similar at 3 years (24% for MAC and 26% for RIC). Overall survival was superior for patients who received MAC compared to those who received RIC (HR, 1.54; 95% CI, 1.07 to 2.2; P = .03). Our data show that patients who received MAC were at higher risk of late TRM compared with those who received RIC; however, because of the exceedingly high rates of relapse in the RIC arm, overall survival remained significantly better for patients who received MAC. Among patients with MDS or AML eligible for either MAC or RIC regimens, long-term follow up demonstrates a survival advantage for patients who received MAC.

Updated prevalence, predictors and treatment outcomes for bronchiolitis obliterans syndrome after allogeneic stem cell transplantation

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS) after allogeneic haemopoietic stem cell transplant (HSCT) is an under-recognised and difficult to treat disease. This occurs in the context of limited clinical research and inconsistent diagnostic criteria.

METHOD

Retrospective data was collected on 275 patients who underwent allogeneic HSCT at an Australian tertiary hospital between 2007 and 2017. The prevalence of BOS, defined by 2014 National Institute of Health criteria, as well as predictors for BOS and mortality were determined. Treatment outcomes, using serial spirometry, were compared between patients who received early versus late immunosuppression for BOS.

RESULTS

The prevalence of BOS was 9.1%. Myeloablative conditioning (OR: 2.7, 95%CI: 1.13-6.50, p = 0.03) and extra-pulmonary chronic graft-versus-host disease (OR 2.62, 95% CI: 1.04-6.60, p = 0.04) were associated with BOS. There was reduced median survival in the BOS group compared with the non-BOS group, but this was not statistically significant (4.1years (IQR: 2.8, 6.8) versus 4.6years (IQR: 2.4, 7.8), respectively, p = 0.33). The vast majority (87.5%) of BOS patients failed to attain improvement in FEV1 at 12 months, regardless of treatment strategy. Patients who underwent a late immunosuppression strategy had worse mean FEV1 decline compared to those who received early immunosuppression (-36.3% versus -1.6%, respectively, p = 0.03).

CONCLUSION

BOS is a common and progressive disease following HSCT and is largely refractory to current treatment strategies. Compared to late immunosuppression, early augmentation of immunosuppression may slow lung function deterioration in the short term. However, further research is urgently needed to identify effective prevention and treatment strategies for BOS.

Impact of Conditioning Intensity and Genomics on Relapse After Allogeneic Transplantation for Patients With Myelodysplastic Syndrome

PURPOSE

Patients with myelodysplastic syndrome (MDS) are at risk of relapse after allogeneic hematopoietic cell transplantation. The utility of ultra-deep genomic testing to predict and the impact of conditioning intensity to prevent MDS relapse are unknown.

METHODS

Targeted error-corrected DNA sequencing was performed on preconditioning blood samples from patients with MDS (n = 48) from the Blood and Marrow Transplant Clinical Trials Network 0901 phase III randomized clinical trial, which compared outcomes by allogeneic hematopoietic cell transplantation conditioning intensity in adult patients with < 5% marrow myeloblasts and no leukemic myeloblasts in blood on morphological analysis at the time of pretransplant assessment. Clinical end points (53-month median follow-up) included transplant-related mortality (TRM), relapse, relapse-free survival (RFS), and overall survival (OS). Of the 48 patients examined, 14 experienced TRM, 23 are relapse-free, and 11 relapsed, of which 7 died.

RESULTS

Using a previously described set of 10 gene regions, 42% of patients (n = 20) had mutations detectable before random assignment to reduced intensity conditioning (RIC) or myeloablative conditioning (MAC). Testing positive was associated with increased rates of relapse (3-year relapse, 40% v 11%; P = .022) and decreased OS (3-year OS, 55% v 79%, P = .045). In those testing positive, relapse rates were higher (3-year relapse, 75% v 17%; P = .003) and RFS was lower (3-year RFS, 13% v 49%; P = .003) in RIC versus MAC arms. Testing additional genes, including those associated with MDS, did not improve prognostication.

CONCLUSION

This study provides evidence that targeted DNA sequencing in patients with MDS before transplant can identify those with highest post-transplant relapse rates. In those testing positive, random assignment to MAC lowered but did not eliminate relapse risk.

Fractionated busulfan myeloablative conditioning improves survival in older patients with acute myeloid leukemia and myelodysplastic syndrome

BACKGROUND

A myeloablative conditioning regimen can be safely given to older patients and those with comorbidities without increasing nonrelapse mortality (NRM) by fractionating the dose of intravenous busulfan. How this approach compares in efficacy with traditional, nonfractionated, lower dose regimens is unknown.

METHODS

Outcomes were compared in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome who received either myeloablative, fractionated busulfan (f-Bu) dosed to achieve an area under the curve of 20,000 μmol per minute (f-Bu20K) over 2 weeks (n = 84) or a standard, nonfractionated, lower busulfan dose regimen of 16,000 μmol per minute (Bu16K) over 4 days (n = 78). Both groups also received fludarabine 40 mg/m² intravenously for 4 days. Graft-versus-host disease prophylaxis was tacrolimus and methotrexate. Patients in the Bu16K group who had unrelated donors also received antithymocyte globulin. The primary endpoint was progression-free survival.

RESULTS

Roughly one-half of the patients were aged >65 years, approximately 40% had poor-risk cytogenetics, approximately 40% of those with AML were not in complete remission, and approximately 40% had a comorbidity index >3. At 2 years, progression-free survival was significantly improved in the f-Bu20K group compared with the Bu16K group (45% vs 24%, respectively; hazard ratio [HR], 0.6; 95% CI, 0.4-0.8; P = .004). This was because of a significant reduction in progression (34% vs 59%, respectively; HR, 0.5; 95% CI, 0.3-0.8; P = .003) without any increase in NRM (21% vs 15%, respectively; HR, 1.4; 95% CI, 0.7-3; P = .3), which resulted in improved overall survival (51% vs 31%, respectively; HR, 0.6; 95% CI, 0.3-0.9; P = .01).

CONCLUSIONS

A myeloablative, fractionated busulfan regimen reduces relapse and improves survival without increasing NRM in older patients with AML and myelodysplastic syndrome.

Stopping tyrosine kinase inhibitors started after allogeneic HCT in patients with Philadelphia chromosome-positive leukemia

For patients with Philadelphia chromosome (Ph)-positive leukemia, there is no consensus regarding how long tyrosine kinase inhibitors (TKI) should be given or whether TKI could be stopped if TKI is administrated after allogeneic hematopoietic cell transplantation (allo-HCT). We analyzed relapse-free survival (RFS) in 92 allo-HCT patients who received TKI for >3 months after allo-HCT, and aimed to develop a novel indicator, called as current TKI- & relapse-free (cTRFree) achievement. TKI after allo-HCT was started as planned in 39 patients, based on measurable residual disease (MRD) in 53 at a median of 152 days after allo-HCT. There was no difference in post-TKI RFS between the planned and MRD-based starting groups (P = 0.69). Second-generation TKIs were associated with superior RFS in Ph-positive acute leukemia (HR 2.71, P = 0.031). TKI was stopped before relapse in 48 patients. Stopping TKI as a time-dependent covariate was not associated with subsequent hematological relapse (HR 1.18, P = 0.72). In the TKI-stop group, TKI administration for >6 months tended to be associated with superior RFS (HR = 0.30, P = 0.08). As an indicator of transplant success, cTRFree was 35% 5 years after starting TKI. TKI could be stopped for recipients with sustained undetectable MRD. However, further prospective studies will be required to establish clinical recommendations.

Successful treatment of two relapsed patients with t(11;19)(q23;p13) acute myeloid leukemia by CLAE chemotherapy sequential with allogeneic hematopoietic stem cell transplantation: Case reports

The prognosis of patients with relapsed/refractory acute myeloid leukemia (R/R AML) is poor, with a 3-year overall survival rate of 10%. Patients with translocation (t)(11;19)(q23;p13) have a higher risk of relapse and there is no optimal regimen for these patients. The present study treated two young patients with t(11;19)(q23;p13) AML, who relapsed after one or two cycles of consolidation, with a salvage treatment consisting of sequential cladribine, cytarabine and etoposide (CLAE) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). Both neutrophil and platelet engraftments were achieved within 15 days, and no severe transplant-related complications and graft-versus-host diseases were observed. Following allo-HSCT, both patients achieved complete hematologic and cytogenetic remission. Decitabine was used for the prophylaxis of relapse. The two patients remained alive and disease-free for 100 days following allo-HSCT. The results presented here suggest that CLAE regimen sequential with allo-HSCT may be effective in treating patients with R/R AML, with t(11;19)(q23;p13). However, further studies and a larger sample size are required to validate the effectiveness of this treatment regimen.

Development of Telintra as an Inhibitor of Glutathione S-Transferase P

Glutathione S-transferase P (GSTP) is a component of a complex series of pathways that provide cellular redox homeostasis. It is an abundant protein in certain tumors and is over-expressed in cancer drug resistance. It has diverse cellular functions that include, thiolase activities with small electrophilic agents or susceptible cysteine residues on the protein to mediate S-glutathionylation, and chaperone binding with select protein kinases. Preclinical and clinical testing of a nanomolar inhibitor of GSTP, TLK199 (Telintra; Ezatiostat) has indicated a role for the enzyme in hematopoiesis and utility for the drug in the treatment of patients with myelodysplastic syndrome.

Allogeneic stem cell transplant in patients with acute myeloid leukemia and karnofsky performance status score less than or equal to 80%: A study from the acute leukemia working party of the European Society for Blood and Marrow Transplantation (EBMT)

Limited data are currently available on the outcome of patients with acute myeloid leukemia (AML) undergoing allogeneic stem cell transplantation (allo-SCT) with a reduced performance status. We herein present the results of a registry study on 2,936 AML patients undergoing allo-SCT in first remission (CR1) with a Karnofsky Performance Status (KPS) score less than or equal to 80%. Two-year leukemia-free survival (LFS), overall survival (OS) and graft-versus-host disease (GVHD)-free, and relapse-free survival (GRFS) rates were 54%, 59%, and 41%, respectively. In multivariable analysis, patients with a KPS score = 80% had lower non-relapse mortality (NRM) and superior OS in comparison to patients with a KPS score <80% (p < 0.001). In the subgroup of patients with a KPS score =80%, a reduced-intensity conditioning (RIC) regimen was associated with an increased risk of relapse (p = 0.002) and lower GRFS (p < 0.001) compared to myeloablative conditioning (MAC). Differently, in patients with a KPS score <80%, a RIC regimen resulted in lower NRM (p < 0.001), whereas relapse incidence did not differ, thus leading to an improved GRFS (p = 0.008) as compared to MAC. A transplant from a matched sibling donor (MSD) was associated with a reduced incidence of grade III-IV acute GVHD (p < 0.01) and NRM (p < 0.01) in comparison to other donor types. In conclusion, allo-SCT appears feasible in AML patients with a jeopardized KPS score. Survival is significantly affected by the conditioning intensity, which should be adjusted according to the severity of KPS impairment.

Myeloablative Versus Reduced Intensity Conditioning Regimens for Allogeneic Hematopoietic Stem Cell Transplant for Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Retrospective Analysis

The conditioning regimens used for the allo-HSCT include either myeloablative conditioning (MAC) or reduced intensity conditioning (RIC) regimens based on the age, performance status and co-morbidities. Studies comparing the survival outcomes of RIC and MAC allo-HSCT in AML and MDS patients have reported contradictory results. We therefore retrospectively analyzed our data of AML and MDS patients who received MAC and RIC allo-HSCT at our center and compared the long term outcome of the two conditioning regimens. One hundred twenty six consecutive patients were evaluated, 32 (25.4%) underwent MAC allo-HSCT and 94 (74.6%) underwent RIC allo-HSCT. The most common MAC regimen used was busulfan plus cyclophosphamide and the most common RIC regimen used was fludarabine plus melphalan. The median age was higher in RIC group (44 years, range 4-75 years) compared to MAC group (31 yrs, range 6-51 yrs, p = 0.001). There was no significant difference in terms of overall survival (p = 0.498), relapse-free survival (p = 0.791) and non-relapse mortality (p = 0.366) between the two groups. In multivariate analysis, only chronic graft-versus-host disease resulted in decreased risk of relapse and improved overall survival irrespective of the conditioning regimens used.

Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia of the Elderly: Review of Literature and New Perspectives

Acute myeloid leukemia (AML) in patients over the age of 60 carries a poor prognosis, mainly due to unsatisfactory control of leukemia with chemotherapy alone. Allogeneic hemopoietic stem cell transplantation (HSCT) would provide significant anti-leukemic effect but is associated with morbidity and mortality, especially in older patients with comorbidities. Reduced-intensity conditioning (RIC) and non-myeloablative (NMA) conditioning regimens have been designed and have led to improved outcomes in this older patient population. New targeted agents, such as Flt3 inhibitors, are currently being used to improve the control of AML further and may be incorporated in a transplant approach. The increasing knowledge of AML in the elderly is currently being associated with a multidimensional approach to identify eligibility and design tailored transplant platforms.

Myeloablative Conditioning for Allogeneic Transplantation Results in Superior Disease-Free Survival for Acute Myelogenous Leukemia and Myelodysplastic Syndromes with Low/Intermediate but not High Disease Risk Index: A Center for International Blood and Marrow Transplant Research Study

Compared with reduced-intensity conditioning (RIC), myeloablative conditioning (MAC) is generally associated with lower relapse risk after allogeneic hematopoietic cell transplantation (HCT) for acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS). However, disease-specific risk factors in AML/MDS can further inform when MAC and RIC may yield differential outcomes. We analyzed HCT outcomes stratified by the Disease Risk Index (DRI) in 4387 adults (age 40 to 65 years) to identify the impact of conditioning intensity. In the low/intermediate-risk DRI cohort, RIC was associated with lower nonrelapse mortality (NRM) (hazard ratio [HR], .74; 95% confidence interval [CI], .62 to .88; P < .001) but significantly greater relapse risk (HR, 1.54; 95% CI, 1.35 to 1.76; P < .001) and thus inferior disease-free survival (DFS) (HR, 1.19; 95% CI, 1.07 to 1.33; P = .001). In the high/very high-risk DRI cohort, RIC was associated with marginally lower NRM (HR, .83; 95% CI, .68 to 1.00; P = .051) and significantly higher relapse risk (HR, 1.23; 95% CI, 1.08 to 1.41; P = .002), leading to similar DFS using either RIC or MAC. These data support MAC over RIC as the preferred conditioning intensity for patients with AML/MDS with low/intermediate-risk DRI, but with a similar benefit as RIC in high/very high-risk DRI. Novel MAC regimens with less toxicity could benefit all patients, but more potent antineoplastic approaches are needed for the high/very-high risk DRI group.

Myeloablative vs reduced intensity T-cell-replete haploidentical transplantation for hematologic malignancy

In the absence of prospective studies that examine the effect of conditioning regimen intensity after T-cell-replete haploidentical transplant for acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS), a retrospective cohort analysis was performed. Of the 1325 eligible patients (AML, n = 818; ALL, n = 286; and MDS, n = 221), 526 patients received a myeloablative regimen and 799 received a reduced-intensity regimen. Graft-versus-host disease prophylaxis was uniform with posttransplant cyclophosphamide, a calcineurin inhibitor, and mycophenolate mofetil. The primary end point was disease-free survival. Cox regression models were built to study the effect of conditioning regimen intensity on transplant outcomes. For patients aged 18 to 54 years, disease-free survival was lower (hazard ratio [HR], 1.34; 42% vs 51%; P = .007) and relapse was higher (HR, 1.51; 44% vs 33%; P = .001) with a reduced-intensity regimen compared with a myeloablative regimen. Nonrelapse mortality did not differ according to regimen intensity. For patients aged 55 to 70 years, disease-free survival (HR, 0.97; 37% vs 43%; P = .83) and relapse (HR, 1.32; 42% vs 31%; P = .11) did not differ according to regimen intensity. Nonrelapse mortality was lower with reduced-intensity regimens (HR, 0.64; 20% vs 31%; P = .02). Myeloablative regimens are preferred for AML, ALL, and MDS; reduced-intensity regimens should be reserved for those unable to tolerate myeloablation.

Increased overall and bacterial infections following myeloablative allogeneic HCT for patients with AML in CR1

Presumably, reduced-intensity/nonmyeloablative conditioning (RIC/NMA) for allogeneic hematopoietic cell transplantation (alloHCT) results in reduced infections compared with myeloablative conditioning (MAC) regimens; however, published evidence is limited. In this Center for International Blood and Marrow Transplant Research study, 1755 patients (aged ≥40 years) with acute myeloid leukemia in first complete remission were evaluated for infections occurring within 100 days after T-cell replete alloHCT. Patients receiving RIC/NMA (n = 777) compared with those receiving MAC (n = 978) were older and underwent transplantation more recently; however, the groups were similar regarding Karnofsky performance score, HCT-comorbidity index, and cytogenetic risk. One or more infections occurred in 1045 (59.5%) patients (MAC, 595 [61%]; RIC/NMA, 450 [58%]; P = .21) by day 100. The median time to initial infection after MAC conditioning occurred earlier (MAC, 15 days [range, <1-99 days]; RIC/NMA, 21 days [range, <1-100 days]; P < .001). Patients receiving MAC were more likely to experience at least 1 bacterial infection by day 100 (MAC, 46% [95% confidence interval (CI), 43-49]; RIC/NMA, 37% [95% CI, 34-41]; P = .0004), whereas at least a single viral infection was more prevalent in the RIC/NMA cohort (MAC, 34% [95% CI, 31-37]; RIC/NMA, 39% [95% CI, 36-42]; P = .046). MAC remained a risk factor for bacterial infections in multivariable analysis (relative risk, 1.44; 95% CI, 1.23-1.67; P < .0001). Moreover, the rate of any infection per patient-days at risk in the first 100 days (infection density) after alloHCT was greater for the MAC cohort (1.21; 95% CI, 1.11-1.32; P < .0001). RIC/NMA was associated with reduced infections, especially bacterial infections, in the first 100 days after alloHCT.

Conditioning Intensity, Pre-Transplant Flow Cytometric Measurable Residual Disease, and Outcome in Adults with Acute Myeloid Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

How conditioning intensity is related to outcomes of AML patients undergoing allografting in morphologic remission is an area of great ongoing interest. We studied 743 patients in morphologic remission and known pre-transplant measurable residual disease (MRD) status determined by multiparameter flow cytometry (MFC) who received a first allograft after myeloablative, reduced intensity, or nonmyeloablative conditioning (MAC, RIC, and NMA). Overall, relapse-free survival (RFS) and overall survival (OS) were longer after MAC than RIC or NMA conditioning, whereas relapse risks were not different. Among MRD^pos patients, 3-year estimates of relapse risks and survival were similar across conditioning intensities. In contrast, among MRD^neg patients, 3-year RFS and OS were longer for MAC (69% and 71%) than RIC (47% and 55%) and NMA conditioning (47% and 52%). Three-year relapse risks were lowest after MAC (18%) and highest after NMA conditioning (30%). Our data indicate an interaction between conditioning intensity, MFC-based pre-transplant MRD status, and outcome, with benefit of intensive conditioning primarily for patients transplanted in MRD^neg remission. Differing from recent findings from other studies that indicated MAC is primarily beneficial for some or all patients with MRD^pos pre-HCT status, our data suggest MAC should still be considered for MRD^neg AML patients if tolerated.

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.

Haploidentical related donor vs matched sibling donor allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia and myelodysplastic syndrome aged over 50 years: A single-center retrospective study

Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is a potentially curative therapeutic option for patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Increasing data suggest that haploidentical donor (HID) transplantation achieve comparable outcomes with HLA‐matched sibling donor (MSD) in adult AML/MDS. This retrospective study compared the outcomes of AML or MDS patients age ≥50 years underwent HID and MSD transplantation. One hundred and fifty‐six patients were enrolled in this study, including 75 HID and 81 MSD transplantation. The 100‐day cumulative incidence of II‐IV° acute graft‐versus‐host disease (GVHD) was 33.3 ± 5.4% vs 22.2 ± 4.6%, respectively, in HID and MSD groups (P = .066), and III‐IV° acute GVHD was not significantly different between two groups (5.3%±2.6% vs 6.2%±2.7%, respectively, P = .823). The 2‐year cumulative incidence of limited and extensive chronic GVHD was not statistically different in HID and MSD groups (20.9 ± 5.5% vs 18.9 ± 4.8% and 13.0 ± 4.7% vs 19.7 ± 5.0%, P = .889 and P = .269, respectively). The 2‐year cumulative incidences of relapse (27.0 ± 5.6% vs 22.7 ± 5.1%, P = .509), 2‐year overall survival (63.0 ± 5.8% vs 66.7 ± 5.4%, P = .454), 2‐year transplant‐related mortality (17.2 ± 4.6% vs 17.4 ± 4.4%, P = .847), 2‐year progression‐free survival (59.3 ± 5.8% vs 64.5 ± 5.4%, P = .437), 2‐year GVHD‐free relapse‐free survival (42.6 ± 5.9% vs 40.9 ± 5.6%, P = .964) were not significantly different in the two groups. The present data showed equivalent outcomes in AML or MDS patients age ≥50 years underwent HID and MSD transplantation.

Early Mixed Lymphoid Donor/Host Chimerism is Associated with Improved Transplant Outcome in Patients with Primary or Secondary Myelofibrosis

We investigated risk factors for the development of mixed chimerism in 131 patients who underwent transplantation for myelofibrosis and determined the impact of lymphoid (CD3+) and myeloid (CD33+) chimerism on transplant outcome. Disease risk included DIPSS plus categories low to high. The median patient age was 58 years. Patients were conditioned with high-intensity (myeloablative) or low/reduced-intensity (nonmyeloablative) regimens and received a transplant from a related or unrelated donor. Mixed CD3⁺ chimerism was observed earlier after HCT, whereas CD33⁺ chimerism occurred later. Mixed chimerism was more frequent with low-intensity regimens than with high- intensity regimens. Mixed CD3⁺ chimerism did not lead to graft failure and was associated with a reduced incidence of acute GVHD and improved overall survival (OS) and relapse-free survival, whereas mixed CD33⁺ chimerism was associated with an increased incidence of relapse and reduced OS and relapse-free survival, independent of the CD34⁺ cell dose transplanted. Thus, mixed CD3⁺ chimerism in patients with myelofibrosis had a favorable impact on transplantation outcome and does not require therapeutic interventions.