Allogeneic hematopoietic stem cell transplantation for MDS and CMML: recommendations from an international expert panel

Prognostic impact of the conditioning intensity on outcomes after allogeneic transplantation for MDS with low blasts: a nationwide retrospective study by the adult MDS working group of the Japan Society for Transplantation and Cellular Therapy

Poor prognostic factors, such as transfusion dependency and chromosomal risk, need to be considered in the indication of allogeneic hematopoietic cell transplantation (allo-HCT) for patients harboring myelodysplastic syndromes with less than 5% marrow blasts (MDS-Lo). We analyzed the post-transplant outcomes of 1229 MDS-Lo patients who received myeloablative (MAC)(n = 651), reduced-intensity (RIC)(n = 397), and non-myeloablative conditioning (NMAC) regimens (n = 181). The multivariate analysis revealed that the RIC group had better chronic graft-versus-host disease (GVHD)- and relapse-free survival (CRFS) (P = 0.021), and GVHD- and relapse-free survival (GRFS) than the MAC group (P = 0.001), while no significant differences were observed between the NMAC and MAC groups. In the subgroup analysis, the MAC group has better overall survival (P = 0.008) than the RIC group among patients with an HCT-comorbidity index (HCT-CI) score of 0, while the RIC group had better overall survival (P = 0.029) than the MAC group among those with an HCT-CI score ≥3. According to the type of conditioning regimen, total body irradiation 12 Gy-based MAC regimen showed better OS and CRFS than the other MAC regimen, and comparable outcomes to the RIC regimen. In conclusion, the RIC and NMAC regimens are promising options for MDS-Lo patients in addition to the MAC regimen.

Comparison of Melphalan Dose in Patients with Myelodysplastic Syndrome Undergoing Allogeneic Transplantation with Reduced-Intensity Conditioning

The present study compared lower-dose melphalan (80 mg/m2, FM80) and higher-dose melphalan (140 mg/m2, FM140) when administering reduced-intensity conditioning with fludarabine in adult patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed nationwide registry data (2006 to 2019) and compared transplant outcomes between the 2 groups. Ninety-two patients (median age, 61 [interquartile range, 56 to 65] years) were assigned to the FM80 and FM140 groups by propensity score matching. The 3-year overall survival (OS) rate in the FM140 group (63.9%; 95% confidence interval [CI], 52.9% to 73.0%) was significantly higher than that in the FM80 group (54.2%; 95% CI, 37.1% to 52.1%) (P = .038). The FM140 group had a nonsignificantly (P = .095) lower 3-year cumulative incidence of relapse (15.5%; 95% CI, 8.9% to 23.8% versus 26.0%; 95% CI, 17.3% to 35.5%). The 3-year cumulative incidences of nonrelapse mortality were 22.3% (95% CI, 14.1% to 31.8%) and 23.7% (95% CI, 15.4% to 33.2%) in the FM80 and FM140 groups, respectively (P = .49). The beneficial effect of FM140 was more evident in patients with a poor cytogenetic risk. Our findings suggest the superiority of FM140 in patients with MDS undergoing allo-HSCT, especially in high-risk patients.

Role of reactive oxygen species in myelodysplastic syndromes

Reactive oxygen species (ROS) serve as typical metabolic byproducts of aerobic life and play a pivotal role in redox reactions and signal transduction pathways. Contingent upon their concentration, ROS production not only initiates or stimulates tumorigenesis but also causes oxidative stress (OS) and triggers cellular apoptosis. Mounting literature supports the view that ROS are closely interwoven with the pathogenesis of a cluster of diseases, particularly those involving cell proliferation and differentiation, such as myelodysplastic syndromes (MDS) and chronic/acute myeloid leukemia (CML/AML). OS caused by excessive ROS at physiological levels is likely to affect the functions of hematopoietic stem cells, such as cell growth and self-renewal, which may contribute to defective hematopoiesis. We review herein the eminent role of ROS in the hematological niche and their profound influence on the progress of MDS. We also highlight that targeting ROS is a practical and reliable tactic for MDS therapy.

How I reduce and treat posttransplant relapse of MDS

ABSTRACT

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only potentially curative option for patients with high-risk myelodysplastic syndromes (MDS). Advances in conditioning regimens and supportive measures have reduced treatment-related mortality and increased the role of transplantation, leading to more patients undergoing HSCT. However, posttransplant relapse of MDS remains a leading cause of morbidity and mortality for this procedure, necessitating expert management and ongoing results analysis. In this article, we review treatment options and our institutional approaches to managing MDS relapse after HSCT, using illustrative clinical cases that exemplify different clinical manifestations and management of relapse. We address areas of controversy relating to conditioning regimen intensity, chemotherapeutic bridging, and donor selection. In addition, we discuss future directions for advancing the field, including (1) the need for prospective clinical trials separating MDS from acute myeloid leukemia and focusing on posttransplant relapse, as well as (2) the validation of measurable residual disease methodologies to guide timely interventions.

Engraftment and Measurable Residual Disease Monitoring after Hematopoietic Stem Cell Transplantation: Comparison of Two Chimerism Test Strategies, Next-Generation Sequencing versus a Combination of Short-Tandem Repeats and Quantitative PCR

Chimerism testing supports the study of engraftment and measurable residual disease (MRD) in patients after allogeneic hematopoietic stem cell transplant. In chimerism MRD, relapse can be predicted by increasing mixed chimerism (IMC), recipient increase ≥0.1% in peripheral blood, and proliferating recipient cells as a surrogate of tumor activity. Conventionally, the combination of short-tandem repeat (STR) and quantitative PCR (qPCR) was needed to ensure assay sensitivity and accuracy in all chimerism status. We evaluated the use of next-generation sequencing (NGS) as an alternate technique. The median numbers of informative markers in unrelated/related cases were 124/82 (NGS; from 202 single-nucleotide polymorphism), 5/3 (qPCR), and 17/10 (STR). Assay sensitivity was 0.22% (NGS), 0.1% (qPCR), and 1% (STR). NGS batch (4 to 48 samples) required 19.60 to 24.80 hours and 1.52 to 2.42 hours of hands-on time (comparable to STR/qPCR). NGS assay cost/sample was $91 to $151, similar to qPCR ($99) but higher than STR ($27). Using 56 serial DNAs from six post-transplant patients monitored by the qPCR/STR, the correlation with NGS was strong for percentage recipient (y = 1.102x + 0.010; R2 = 0.968) and percentage recipient change (y = 0.892x + 0.041; R2 = 0.945). NGS identified all 17 IMC events detected by qPCR (100% sensitivity). The NGS chimerism provides sufficient sensitivity, accuracy, and economical/logistical feasibility in supporting engraftment and MRD monitoring.

Outcomes with allogeneic hematopoietic stem cell transplantation in TP53-mutated myelodysplastic syndrome: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to evaluate outcomes after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) in TP53-mutated myelodysplastic syndromes (MDS). A literature search was performed on PubMed, Cochrane, Embase, and Clinicaltrials.gov. After screening 626 articles, eight studies were included. Data were extracted following the PRISMA guidelines and analyzed using the meta-package by Schwarzer et al. We analyzed 540 patients. The pooled median 3 (1-5) year overall survival was 21% (95% CI 0.08-0.37, I2=91%, n=540). The pooled relapse rate was 58.9% (95% CI 0.38-0.77, I2=93%, n=487) at a median of 1.75 (1-3) years. The pooled 4-year progression- free survival was 34.8% (95% CI 0.15-0.57, I2=72%, n=105). Outcomes of Allo-HSCT for TP53-mutated MDS patients remain poor, with 21% OS at three years; however, Allo-HSCT confers a survival advantage as compared to non-transplant palliative therapies. Our findings suggest the need to explore novel therapeutic agents in prospective clinical trials.

Allogeneic Hematopoietic Cell Transplantation in Advanced Systemic Mastocytosis: A retrospective analysis of the DRST and GREM registries

We identified 71 patients with AdvSM (aggressive SM [ASM], SM with an associated hematologic neoplasm [SM-AHN, e.g., acute myeloid leukemia, SM-AML], mast cell leukemia [MCL]) in two national registries (DRST/GREM) who received an allogeneic hematopoietic cell transplantation (alloHCT) performed in Germany from 1999-2021. Median overall survival (OS) of ASM/SM-AHN (n = 30, 45%), SM-AML (n = 28, 39%) and MCL ± AHN (n = 13, 19%) was 9.0, 3.3 and 0.9 years (P = 0.007). Improved median OS was associated with response of SM (17/41, 41%; HR 0.4 [0.2-0.9], P = 0.035) and/or of AHN (26/43, 60%, HR 0.3 [0.1-0.7], P = 0.004) prior to alloHCT. Adverse predictors for OS included absence of KIT D816V (10/61, 16%, HR 2.9 [1.2-6.5], P < 0.001) and a complex karyotype (9/60, 15%, HR 4.2 [1.8-10.0], P = 0.016). HLA-match, conditioning type or transplantation at centers reporting above-average alloHCTs (≥7) had no impact on OS. Taking into account competing events at years 1, 3 and 5, relapse-related mortality and non-relapse mortality rate were 15%/23%, 20%/30% and 23%/35%, respectively. Irrespective of subtype, subsequent treatment response was achieved in 13/30 (43%) patients and was highest on midostaurin/avapritinib (7/9, 78%). We conclude that outcome of alloHCT in AdvSM is more affected by disease phenotype and treatment response prior to transplant than by transplant characteristics.

Identification and surveillance of rare relapse-initiating stem cells during complete remission after transplantation

ABSTRACT

Relapse after complete remission (CR) remains the main cause of mortality after allogeneic stem cell transplantation for hematological malignancies and, therefore, improved biomarkers for early prediction of relapse remains a critical goal toward development and assessment of preemptive relapse treatment. Because the significance of cancer stem cells as a source of relapses remains unclear, we investigated whether mutational screening for persistence of rare cancer stem cells would enhance measurable residual disease (MRD) and early relapse prediction after transplantation. In a retrospective study of patients who relapsed and patients who achieved continuous-CR with myelodysplastic syndromes and related myeloid malignancies, combined flow cytometric cell sorting and mutational screening for persistence of rare relapse-initiating stem cells was performed in the bone marrow at multiple CR time points after transplantation. In 25 CR samples from 15 patients that later relapsed, only 9 samples were MRD-positive in mononuclear cells (MNCs) whereas flowcytometric-sorted hematopoietic stem and progenitor cells (HSPCs) were MRD-positive in all samples, and always with a higher variant allele frequency than in MNCs (mean, 97-fold). MRD-positivity in HSPCs preceded MNCs in multiple sequential samples, in some cases preceding relapse by >2 years. In contrast, in 13 patients in long-term continuous-CR, HSPCs remained MRD-negative. Enhanced MRD sensitivity was also observed in total CD34+ cells, but HSPCs were always more clonally involved (mean, 8-fold). In conclusion, identification of relapse-initiating cancer stem cells and mutational MRD screening for their persistence consistently enhances MRD sensitivity and earlier prediction of relapse after allogeneic stem cell transplantation.

Impact of myelofibrosis on patients with myelodysplastic syndromes following allogeneic hematopoietic stem cell transplantation

BACKGROUND

The prognostic significance of myelofibrosis (MF) grade in patients with myelodysplastic syndrome (MDS) following an allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains elusive.

METHODS

We retrospectively analyzed data from 153 patients with MDS who underwent allo-HSCT and divided the patients into the MF-0/1 (N = 119) and MF-2/3 (N = 34) cohorts to explore the impact of MF on outcomes of allo-HSCT.

RESULTS

The 2-year rates of relapse, non-relapse mortality (NRM), overall survival (OS), and progression-free survival (PFS) were 10.9% (95% confidence interval [CI] 5.9%-17.7%), 16.3% (95% CI 10.2%-23.6%), 76.6% (95% CI 69.0%-85.1%), and 72.8% (95% CI 65.0%-81.5%) in the MF-0/1 cohort, and 16.9% (95% CI 5.8%-32.9%), 14.7% (95% CI 5.3%-28.7%), 71.8% (95% CI 57.6%-89.6%), and 68.4% (95% CI 53.6%-87.2%) in the MF-2/3 cohort, respectively. No significant difference in the outcomes of allo-HSCT was observed between the two cohorts. Both univariate and multivariate analyses confirmed that MF-2/3 in patients with MDS had no effect on the prognosis of transplantation. In addition, major/bidirectional ABO blood type between donors and recipients was an independent risk factor for OS (hazard ratio [HR], 2.55; 95% CI 1.25-5.21; P = 0.010) and PFS (HR, 2.21; 95% CI 1.10-4.42; P = 0.025) in the multivariate analysis. In the subgroup of patients diagnosed with MDS with increased blasts (MDS-IB), it was consistently demonstrated that the clinical outcomes of the MF-2/3 cohort were comparable with those of the MF-0/1 cohort. The risk factors for OS and PFS in patients with MDS-IB were non-complete remission at transplantation and major/bidirectional ABO blood type.

CONCLUSIONS

In conclusion, MF grade had no significant effect on prognosis of allo-HSCT in patients diagnosed with MDS. Major/bidirectional ABO blood type should be carefully considered in the context of more than one available donor.

Peripheral Blood Haploidentical Allogeneic Stem Cell Transplantation in Older Adults with Acute Myeloid Leukemia and Myelodysplastic Syndromes Demonstrates Long Term Survival, Results from Australia and New Zealand Transplant and Cellular Therapies

There is a limited body of evidence for haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in older patients. Previous studies have used a high proportion of bone marrow-derived grafts and a variety of conditioning regimens. In Australia and New Zealand, haplo-HCST is predominantly performed using peripheral blood (PB) with universal use of post-transplantation cyclophosphamide (PTCy). To characterize the outcomes of older recipients undergoing haplo-HSCT for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Data were collected through the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) for patients aged 65 or older receiving a PB haplo-HSCT for AML/MDS between January 2010 and July 2020. A total of 44 patients were included in the analysis. The median follow-up time was 377 days. The median age was 68 (range 65-74) with a median Karnofsky performance status of 90. Thirty patients (68.2%) had AML, whereas 14 (31.8%) had MDS. The median donor age was 40. The most common conditioning regimen was nonmyeloablative fludarabine, cyclophosphamide, and total body irradiation (75%); the remainder of the patients received either melphalan- or busulfan-based regimens, and the majority were reduced intensity, with only 2 patients undergoing myeloablative conditioning. All patients received post-transplantation cyclophosphamide and mycophenolate mofetil, with the majority also receiving tacrolimus (90.5%) and the remainder receiving cyclosporine (9.5%). No patients received anti-thymocyte globulin. Neutrophil engraftment was achieved in 97.6% of patients at a median of 18 days, whereas platelet engraftment was achieved in 92.7% of patients at a median of 28 days. The cumulative incidences of cytomegalovirus (CMV) reactivation and CMV disease were 52.5% and 5.1% at 1 year. The incidence of grade 2-4 acute Graft Versus Host Disease (GVHD) was 18.2%. The incidence of chronic GVHD at 2 years was 40.7%, with extensive chronic GVHD occurring in 17.7% of patients. The incidences of relapse and non-relapse mortality (NRM) at 2 years were 8.8% and 20.7% respectively. The leading causes of death were infection (64.7%) followed by relapse (14.2%). The 2-year overall survival was 74%. Relapse free survival and GVHD free, relapse free survival at 2 years was 70% and 48%. Haplo-HSCT using a peripheral blood graft and PTCy GVHD prophylaxis demonstrates long-term disease control with acceptable rates of NRM for older patients with AML/MDS.

Defining the mutational profile of lower-risk myelodysplastic neoplasm patients with respect to disease progression using next-generation sequencing and pyrosequencing

Introduction

Lower-risk myelodysplastic neoplasms (LR-MDS) comprise the majority of MDS. Despite favourable prognoses, some patients remain at risk of rapid progression. We aimed to define the mutational profile of LR-MDS using next-generation sequencing (NGS), Sanger Sequencing (SSeq), and pyrosequencing.

Material and methods

Samples from 5 primary LR-MDS (67 exons of SF3B1, U2AF1, SRSF2, ZRSR2, TET2, ASXL1, DNMT3A, TP53, and RUNX1 genes) were subjected to NGS. Next, a genomic study was performed to test for the presence of identified DNA sequence variants on a larger group of LR-MDS patients (25 bone marrow [BM], 3 saliva [SAL], and one peripheral blood [PB] sample/s). Both SSeq (all selected DNA sequence variants) and pyrosequencing (9 selected DNA sequence variants) were performed.

Results

Next-generation sequencing results identified 13 DNA sequence variants in 7 genes, comprising 8 mutations in 6 genes (ASXL1, DNMT3A, RUNX1, SF3B1, TET2, ZRSR2) in LR-MDS. The presence of 8 DNA variants was detected in the expanded LR-MDS group using SSeq and pyrosequencing. Mutation acquisition was observed during LR-MDS progression. Four LR-MDS and one acute myeloid leukaemia myelodysplasia-related patient exhibited the presence of at least one mutation. ASXL1 and SF3B1 alterations were most commonly observed (2 patients). Five DNA sequence variants detected in BM (patients: 9, 13) were also present in SAL.

Conclusions

We suggest using NGS to determine the LR-MDS mutational profile at diagnosis and suspicion of disease progression. Moreover, PB and SAL molecular testing represent useful tools for monitoring LR-MDS at higher risk of progression. However, the results need to be confirmed in a larger group.

Hematopoietic cell transplantation (HCT) in MDS patients of older age

Hematopoietic cell transplantation (HCT) has evolved to an essential treatment in younger and more recently in elderly patients with myelodysplastic syndrome (MDS), the age group with the highest incidence. Less intense conditioning regimens and improvements in supportive therapy have reduced considerably transplant related mortality and in the same time increased the access to this curative treatment. Timing of HCT in the course of the disease assumes a crucial role. Detection of disease progression, geriatric assessment, comorbidity evaluation, and identification of transplant-specific risks are becoming increasingly important in this context. Novel statistical methods, molecular biomarkers, and quantification of tumor burden pre- and post-HCT will play an essential role in years to come. More effective and less toxic treatments to reduce the tumor burden before and/or after HCT are expected to improve the outcome. In this review article we discuss the current views and what we can expect.

Outcomes of CMML patients undergoing allo-HCT are significantly worse compared to MDS-a study of the CMWP of the EBMT

Although CMML since long has been separated from MDS, many studies continue to evaluate the outcomes of both diseases after hematopoietic cell transplantation (allo-HCT) together. Data evaluating outcomes of a large CMML cohort after allo-HCT compared to MDS are limited. We aim to compare outcomes of CMML to MDS patients who underwent allo-HCT between 2010 and 2018. Patients ≥18 years with CMML and MDS undergoing allo-HCT reported to the EBMT registry were analyzed. Progression to AML before allo-HCT was an exclusion criterion. Overall survival (OS), progression/relapse-free survival (PFS), relapse incidence (including progression) (REL), and non-relapse mortality (NRM) were evaluated in univariable and multivariable (MVA) Cox proportional hazard models including interaction terms between disease and confounders. In total, 10832 patients who underwent allo-HCT were included in the study, there were a total of 1466 CMML, and 9366 MDS. The median age at time of allo-HCT in CMML (median 60.5, IQR 54.3-65.2 years) was significantly higher than in the MDS cohort (median 58.8, IQR 50.2-64.5 years; p < .001). A significantly higher percentage of CMML patients were male (69.4%) compared to MDS (61.2%; p < .001). There were no clinically meaningful differences in the distribution of Karnofsky score, Sorror HCT-CI score at allo-HCT, and donor type, between the CMML and MDS patients. RIC platforms were utilized in 63.9% of CMML allo-HCT, and in 61.4% of MDS patients (p = .08). In univariable analyses, we found that OS, PFS, and REL were significantly worse in CMML when compared with MDS (all p < .0001), whereas no significant difference was observed in NRM (p = .77). In multivariable analyses, the HR comparing MDS versus CMML for OS was 0.81 (95% CI, 0.74-0.88, p < .001), PFS 0.76 (95% CI 0.70-0.82, p < .001), relapse 0.66 (95% CI 0.59-0.74, p < .001), and NRM 0.87 (95% CI 0.78-0.98, p = .02), respectively. The association between baseline variables and outcome was found to be similar in MDS and CMML (all interaction p > .05) except for a decreasing trend over time of the risk of relapse in CMML (HR allo-HCT per year later 0.94, 95% CI 0.90-0.98), whereas no such trend was observed in MDS (HR 1.00, 95% CI 0.98-1.02). The poor outcome observed for CMML could be related to variables not measured in this study or to factors inherent to the disease itself. This study demonstrates that outcomes of CMML patients after allo-HCT are significantly worse compared to MDS. The results of this study may contribute to future recommendations for allo-HCT in CMML patients.

Recent advances in the application of induced pluripotent stem cell technology to the study of myeloid malignancies

Acquired myeloid malignancies are a spectrum of clonal disorders known to be caused by sequential acquisition of genetic lesions in hematopoietic stem and progenitor cells, leading to their aberrant self-renewal and differentiation. The increasing use of induced pluripotent stem cell (iPSC) technology to study myeloid malignancies has helped usher a paradigm shift in approaches to disease modeling and drug discovery, especially when combined with gene-editing technology. The process of reprogramming allows for the capture of the diversity of genetic lesions and mutational burden found in primary patient samples into individual stable iPSC lines. Patient-derived iPSC lines, owing to their self-renewal and differentiation capacity, can thus be a homogenous source of disease relevant material that allow for the study of disease pathogenesis using various functional read-outs. Furthermore, genome editing technologies like CRISPR/Cas9 enable the study of the stepwise progression from normal to malignant hematopoiesis through the introduction of specific driver mutations, individually or in combination, to create isogenic lines for comparison. In this review, we survey the current use of iPSCs to model acquired myeloid malignancies including myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), acute myeloid leukemia and MDS/MPN overlap syndromes. The use of iPSCs has enabled the interrogation of the underlying mechanism of initiation and progression driving these diseases. It has also made drug testing, repurposing, and the discovery of novel therapies for these diseases possible in a high throughput setting.

Clinical decision-making and treatment of myelodysplastic syndromes

ABSTRACT

The myelodysplastic syndromes (MDSs) constitute a profoundly heterogeneous myeloid malignancy with a common origin in the hemopoietic stem cell compartment. Consequently, patient management and treatment are as heterogeneous. Decision-making includes identifying risk, symptoms, and options for an individual and conducting a risk-benefit analysis. The only potential cure is allogeneic stem cell transplantation, and albeit the fraction of patients with MDS who undergo transplant increase over time because of better management and increased donor availability, a majority are not eligible for this intervention. Current challenges encompass to decrease the relapse risk, the main cause of hematopoietic stem cell transplantation failure. Hypomethylating agents (HMAs) constitute firstline treatment for higher-risk MDSs. Combinations with other drugs as firstline treatment has, to date, not proven more efficacious than monotherapy, although combinations approved for acute myeloid leukemia, including venetoclax, are under evaluation and often used as rescue treatment. The treatment goal for lower-risk MDS is to improve cytopenia, mainly anemia, quality of life, and, possibly, overall survival. Erythropoiesis-stimulating agents (ESAs) constitute firstline treatment for anemia and have better and more durable responses if initiated before the onset of a permanent transfusion need. Treatment in case of ESA failure or ineligibility should be tailored to the main disease mechanism: immunosuppression for hypoplastic MDS without high-risk genetics, lenalidomide for low-risk del(5q) MDS, and luspatercept for MDS with ring sideroblasts. Approved therapeutic options are still scarcer for MDS than for most other hematologic malignancies. Better tools to match disease biology with treatment, that is, applied precision medicines are needed to improve patient outcome.

NLRP3 inflammasome activation and symptom burden in KRAS-mutated CMML patients is reverted by IL-1 blocking therapy

Chronic myelomonocytic leukemia (CMML) is frequently associated with mutations in the rat sarcoma gene (RAS), leading to worse prognosis. RAS mutations result in active RAS-GTP proteins, favoring myeloid cell proliferation and survival and inducing the NLRP3 inflammasome together with the apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), which promote caspase-1 activation and interleukin (IL)-1β release. Here, we report, in a cohort of CMML patients with mutations in KRAS, a constitutive activation of the NLRP3 inflammasome in monocytes, evidenced by ASC oligomerization and IL-1β release, as well as a specific inflammatory cytokine signature. Treatment of a CMML patient with a KRASG12D mutation using the IL-1 receptor blocker anakinra inhibits NLRP3 inflammasome activation, reduces monocyte count, and improves the patient's clinical status, enabling a stem cell transplant. This reveals a basal inflammasome activation in RAS-mutated CMML patients and suggests potential therapeutic applications of NLRP3 and IL-1 blockers.

[Allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes]

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the treatment options for myelodysplastic syndromes (MDS). This treatment is indicated as first-line treatment for high-risk MDS according to the IPSS and R-IPSS classifications and improves overall survival and progression-free survival. However, allo-HSCT is not indicated in first intention for low-risk MDS. It can be discussed in case of cytopenias needing transfusions, poor evolution under other treatment, or in case of poor prognosis molecular anomaly. Allo-HSCT is a treatment that can be complicated by early or late toxicities (graft versus host disease, infections, chemotherapy toxicity…). The decision to do an allo-HSCT is based on the benefit/risk ratio between the risk of progression from MDS to myeloid leukemia and the risk of transplant related mortality, which increases with the patient's age and comorbidities. The indication of a cytoreductive treatment before allo-HSCT depends on the blasts count, and on the delay before the allograft. The use of reduced intensity conditioning regimen and alternative donors such as haploidentical donors, expanded the indications for allo-HSCT. Relapse remains one of the main causes of mortality after allo-HSCT. Some genetic mutations and karyotype anomalies increase the risk of post-transplant relapse. Preventive treatments for relapse are currently being studied. Treatments such as azacytidine, donor lymphocytes infusions or targeted therapies can be used, prophylactically or preemptively.

Therapy-related myelodysplastic syndromes in the genomics era

Therapy-related myelodysplastic syndromes (t-MDS) represent a heterogeneous group of malignancies that arise as a late complication of prior exposure to chemotherapy and/or radiotherapy administered for a primary condition. T-MDS account for approximately 20% of all MDS and are characterized by resistance to current treatment strategies and poor prognosis. Our understanding of t-MDS pathogenesis has considerably improved over the last 5 years with the availability of deep sequencing technologies. T-MDS development is now considered as a multifactorial process resulting from complex interactions between an underlying germline genetic susceptibility, the stepwise acquisition of somatic mutations in hematopoietic stem cells, the clonal selection pressure exerted by cytotoxic therapies, and alterations of the bone marrow microenvironment. The survival of patients with t-MDS is generally poor. This can be explained by both patient-related factors including poor performance status and less tolerance to treatment and disease-related factors, such as the presence of chemoresistant clones, high-risk cytogenetic alterations and molecular features (e.g. high frequency of TP53 mutations). Around 50% of t-MDS patients are classified as high/very high risk based on IPSS-R or IPSS-M scores, versus 30% in de novo MDS. Long-term survival is only achieved in a minority of t-MDS patients who receive allogeneic stem cell transplantation, but the development of novel drugs may open new therapeutic opportunities, especially in unfit patients. Further investigations are needed to improve the identification of patients at higher risk of developing t-MDS and determine whether primary disease treatment can be modified to prevent the occurrence of t-MDS.

Impact of a novel prognostic model on allogeneic hematopoietic stem cell transplantation outcomes in patients with CMML

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell malignancy, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curable treatment. The outcomes after transplant are influenced by both disease characteristics and patient comorbidities. To develop a novel prognostic model to predict the post-transplant survival of CMML patients, we identified risk factors by applying univariable and multivariable Cox proportional hazards regression to a derivation cohort. In multivariable analysis, advanced age (hazard ratio [HR] 3.583), leukocyte count (HR 3.499), anemia (HR 3.439), bone marrow blast cell count (HR 2.095), and no chronic graft versus host disease (cGVHD; HR 4.799) were independently associated with worse survival. A novel prognostic model termed ABLAG (Age, Blast, Leukocyte, Anemia, cGVHD) was developed and the points were assigned according to the regression equation. The patients were categorized into low risk (0-1), intermediate risk (2, 3), and high risk (4-6) three groups and the 3-year overall survival (OS) were 93.3% (95%CI, 61%-99%), 78.9% (95%CI, 60%-90%), and 51.6% (95%CI, 32%-68%; p < .001), respectively. In internal and external validation cohort, the area under the receiver operating characteristic (ROC) curves of the ABLAG model were 0.829 (95% CI, 0.776-0.902) and 0.749 (95% CI, 0.684-0.854). Compared with existing models designed for the nontransplant setting, calibration plots, and decision curve analysis showed that the ABLAG model revealed a high consistency between predicted and observed outcomes and patients could benefit from this model. In conclusion, combining disease and patient characteristic, the ABLAG model provides better survival stratification for CMML patients receiving allo-HSCT.

ESMO/ASCO Recommendations for a Global Curriculum in Medical Oncology Edition 2023

The European Society for Medical Oncology (ESMO) and ASCO are publishing a new edition of the ESMO/ASCO Global Curriculum (GC) with contributions from more than 150 authors. The purpose of the GC is to provide recommendations for the training of physicians in medical oncology and to establish a set of educational standards for trainees to qualify as medical oncologists. This edition builds on prior ones in 2004, 2010, and 2016 and incorporates scientific advances and input from an ESMO ASCO survey on GC adoption conducted in 2019, which revealed that GC has been adopted or adapted in as many as two thirds of the countries surveyed. To make GC even more useful and applicable, certain subchapters were rearranged into stand-alone chapters, that is, cancer epidemiology, diagnostics, and research. In line with recent progress in the field of multidisciplinary cancer care new (sub)chapters, such as image-guided therapy, cell-based therapy, and nutritional support, were added. Moreover, this edition includes an entirely new chapter dedicated to cancer control principles, aiming to ensure that medical oncologists are able to identify and implement sustainable and equitable cancer care, tailored to local needs and resources. Besides content renewal, modern didactic principles were introduced. GC content is presented using two chapter templates (cancer-specific and non-cancer-specific), with three didactic points (objectives, key concepts, and skills). The next step is promoting GC as a contemporary and comprehensive document applicable all over the world, particularly due to its capacity to harmonize education in medical oncology and, in so doing, help to reduce global disparities in cancer care.

Decitabine/Cedazuridine in the Management of Myelodysplastic Syndrome and Chronic Myelomonocytic Leukemia in Canada

The management of myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) is limited and remains an unmet need. Decitabine/cedazuridine (DEC-C, ASTX727) is Canada's first and only approved oral hypomethylating agent for MDS and CMML. We characterized the real-world use of DEC-C through a Canadian compassionate use program. Demographic and clinical data from 769 patients enrolled in Taiho Pharma Canada's Patient Support Program were collected and analyzed. These patients represent a collection period from 10 November 2020 to 31 August 2022 with a median age of 76 years. Among 651 patients who started DEC-C, the median treatment duration was 4.2 cycles. The median overall and progression-free survival were 21.6 and 10.7 months, respectively. Among 427 patients who discontinued treatment, the majority (69.5%) stopped due to death (n = 164) or disease progression (n = 133). Multivariable cox regression showed that age, province of residence, blast counts, antibiotic prophylaxis, and number of dose reductions and delays were not significantly associated with overall and progression-free survival. DEC-C is a promising alternative to parenteral hypomethylating agent therapy, and it likely addresses an important unmet need for effective and convenient therapies in this setting.

Cell-free DNA measurable residual disease as a predictor of postallogeneic hematopoietic cell transplant outcomes

The measurable residual disease (MRD) assessment provides an attractive predictor of allogeneic hematopoietic cell transplnat (alloHCT) outcomes. Cell-free DNA (cfDNA) has been applied to diagnosis, early detection, and disease burden monitoring in various tumors, but its utility as an MRD test in myeloid malignancies has not been systematically evaluated. We sought to determine the differential sensitivity between bone marrow (BM) and cfDNA MRD and to assess the effect of cfDNA MRD on alloHCT outcomes. The technical and clinical validation cohorts, including 82 patients participating in clinical trials (Bone Marrow Transplant Clinical Trials Network-0201 and 0402), were used. Ultradeep error-corrected targeted sequencing was performed on plasma and BM-derived DNA. We demonstrated that 94.6% (range, 93.9-95.3) of cfDNA was derived from hematopoietic tissue. The mutant allele fraction was congruent between BM and cfDNA (rho = 0.8; P < .0001); however, cfDNA seemed to be more sensitive in detecting clones with a variant allele frequency (VAF) of <0.26%. cfDNA-MRD clearance by day 90 after alloHCT (D90) was associated with improved relapse-free survival (RFS, median survival not reached vs 5.5 months; P < .0001) and overall survival (OS, median survival not reached vs 7.3 months; P < .0001) when compared with patients with persistent MRD. Irrespective of pre-alloHCT MRD, D90 cfDNA MRD was associated with inferior 2-year OS (16.7% vs 84.8%; P < .0001) and RFS (16.7% vs 80.7%; P < .0001). cfDNA seems to be an accurate, minimally invasive alternative to BM aspirates in MRD assessment and confers important prognostic implications in patients with myeloid malignancies undergoing alloHCT.

Intestinal microbiota controls graft-versus-host disease independent of donor-host genetic disparity

Acute graft-versus-host disease (aGVHD) remains a major limitation of allogeneic stem cell transplantation (SCT), and severe intestinal manifestation is the major cause of early mortality. Intestinal microbiota control MHC class II (MHC-II) expression by ileal intestinal epithelial cells (IECs) that promote GVHD. Here, we demonstrated that genetically identical mice of differing vendor origins had markedly different intestinal microbiota and ileal MHC-II expression, resulting in discordant GVHD severity. We utilized cohousing and antibiotic treatment to characterize the bacterial taxa positively and negatively associated with MHC-II expression. A large proportion of bacterial MHC-II inducers were vancomycin sensitive, and peri-transplant oral vancomycin administration attenuated CD4+ T cell-mediated GVHD. We identified a similar relationship between pre-transplant microbes, HLA class II expression, and both GVHD and mortality in a large clinical SCT cohort. These data highlight therapeutically tractable mechanisms by which pre-transplant microbial taxa contribute to GVHD independently of genetic disparity.

CPX-351 in higher risk myelodysplastic syndrome and chronic myelomonocytic leukaemia: a multicentre, single-arm, phase 2 study

BACKGROUND

CPX-351, an encapsulated form of cytarabine and daunorubicin, has shown greater efficacy than the classic 3 + 7 treatment administration in secondary acute myeloid leukaemia. Given that higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia share similarities with secondary acute myeloid leukaemia, we aimed to investigate the safety and efficacy of CPX-351 in this context.

METHODS

This investigator-initiated two-cohort phase 2 trial was conducted by the Groupe Francophone des Myélodysplasies, with 12 participating centres in France. It comprised cohort A (reported here and completed), which included patients in first-line treatment, and cohort B, which was stopped for lack of inclusion (ie, not enough patients met the inclusion criteria), for patients with hypomethylating agent failure that is not reported here. Cohort A enrolled patients with newly diagnosed higher-risk myelodysplastic syndrome or chronic myelomonocytic leukaemia (aged 18-70 years old) with an Eastern Cooperative Oncology Group performance status of 0-1. Intravenous CPX-351 (100 mg/m2 cytarabine and 44 mg/m2 daunorubicin) was given on days 1, 3, and 5, with a second induction cycle given (same daily dose on days 1 and 3) if at least a partial response was not reached. Patients who responded could receive up to four monthly consolidation cycles (same daily dose on day 1) or allogeneic haematopoietic stem-cell transplantation (HSCT). Overall response rate after one or two induction courses according to European LeukemiaNet 2017 acute myeloid leukaemia was the primary endpoint after CPX-351 induction, whether patients received one or two induction cycles. Safety was assessed in all patients enrolled (in cohort A). This trial is registered with ClinicalTrials.gov, NCT04273802.

FINDINGS

Between April 29, 2020, and Feb 10, 2021, 21 (68%) male and ten (32%) female patients were enrolled. 27 (87%) of 31 patients responded (95% CI 70-96). 16 (52%) of the 31 patients received at least one consolidation cycle. 30 (97%) of the 31 patients included were initially considered eligible for allogeneic HSCT and 29 (94%) of the 31 patients had the procedure. Median follow-up was 16·1 months (IQR 8·3-18·1). The most common grade 3-4 adverse events were pulmonary (eight [26%] of 31 patients) and cardiovascular (six [19%] of 31 patients). There were 14 serious adverse events (mainly hospitalisation for infection [n=5] and only one was treatment-related) and no treatment-related death.

INTERPRETATION

CPX-351 appears to be active and safe in patients with higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia, allowing bridging to allogenic HSCT in most patients.

FUNDING

Jazz Pharmaceuticals.

Management of Patients with Lower-Risk Myelodysplastic Neoplasms (MDS)

Myelodysplastic neoplasms (MDS) are a heterogenous group of clonal hematologic disorders characterized by morphologic dysplasia, ineffective hematopoiesis, and cytopenia. In the past year, the classification of MDS has been updated in the 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours and the International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemia with incorporation of morphologic, clinical, and genomic data. Furthermore, the more comprehensive International Prognostic Scoring System-Molecular (IPSS-M) allows for improved risk stratification and prognostication. These three developments allow for more tailored therapeutic decision-making in view of the expanding treatment options in MDS. For patients with lower risk MDS, treatment is aimed at improving cytopenias, usually anemia. The recent approval of luspatercept and decitabine/cedazuridine have added on to the current armamentarium of erythropoietic stimulating agents and lenalidomide (for MDS with isolated deletion 5q). Several newer agents are being evaluated in phase 3 clinical trials for this group of patients, such as imetelstat and oral azacitidine. This review provides a summary of the classification systems, the prognostic scores and clinical management of patients with lower risk MDS.

Proposals for Clinical Trials in Chronic Myelomonocytic Leukemia

OPINION STATEMENT

Chronic myelomonocytic leukemia (CMML) is a clonal hematologic malignancy of mostly older individuals that exhibits both myelodysplastic and myeloproliferative features. CMML presentation and outcome are variable, reflecting genetic and clinical heterogeneity. Hypomethylating agents are the mainstay of therapy but induce complete remissions in less than 20% of patients and do not prolong survival compared to hydroxyurea. Allogeneic stem cell transplant (ASCT) is potentially curative, but few patients qualify due to advanced age and/or comorbidities. Work of the past several years has identified key molecular pathways that drive disease proliferation and transformation to acute leukemia, including JAK/STAT and MAPK signaling and epigenetic dysregulation. There is increasingly compelling evidence that inflammation is a major driver of CMML progression. Thus far however, this mechanistic knowledge has not yet been translated into improved outcomes, suggesting that fundamentally new approaches are required. In this review, we discuss the disease course, new classifications, and current treatment landscape of CMML. We review ongoing clinical studies and discuss options for rationally based future clinical trials.

Real-World Validation of Molecular International Prognostic Scoring System for Myelodysplastic Syndromes

PURPOSE

Myelodysplastic syndromes (MDS) are heterogeneous myeloid neoplasms in which a risk-adapted treatment strategy is needed. Recently, a new clinical-molecular prognostic model, the Molecular International Prognostic Scoring System (IPSS-M) was proposed to improve the prediction of clinical outcome of the currently available tool (Revised International Prognostic Scoring System [IPSS-R]). We aimed to provide an extensive validation of IPSS-M.

METHODS

A total of 2,876 patients with primary MDS from the GenoMed4All consortium were retrospectively analyzed.

RESULTS

IPSS-M improved prognostic discrimination across all clinical end points with respect to IPSS-R (concordance was 0.81 v 0.74 for overall survival and 0.89 v 0.76 for leukemia-free survival, respectively). This was true even in those patients without detectable gene mutations. Compared with the IPSS-R based stratification, the IPSS-M risk group changed in 46% of patients (23.6% and 22.4% of subjects were upstaged and downstaged, respectively).In patients treated with hematopoietic stem cell transplantation (HSCT), IPSS-M significantly improved the prediction of the risk of disease relapse and the probability of post-transplantation survival versus IPSS-R (concordance was 0.76 v 0.60 for overall survival and 0.89 v 0.70 for probability of relapse, respectively). In high-risk patients treated with hypomethylating agents (HMA), IPSS-M failed to stratify individual probability of response; response duration and probability of survival were inversely related to IPSS-M risk.Finally, we tested the accuracy in predicting IPSS-M when molecular information was missed and we defined a minimum set of 15 relevant genes associated with high performance of the score.

CONCLUSION

IPSS-M improves MDS prognostication and might result in a more effective selection of candidates to HSCT. Additional factors other than gene mutations can be involved in determining HMA sensitivity. The definition of a minimum set of relevant genes may facilitate the clinical implementation of the score.

Telomere biology: from disorders to hematological diseases

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Regulation of hematopoietic stem cells differentiation, self-renewal, and quiescence through the mTOR signaling pathway

Hematopoietic stem cells (HSCs) are important for the hematopoietic system because they can self-renew to increase their number and differentiate into all the blood cells. At a steady state, most of the HSCs remain in quiescence to preserve their capacities and protect themselves from damage and exhaustive stress. However, when there are some emergencies, HSCs are activated to start their self-renewal and differentiation. The mTOR signaling pathway has been shown as an important signaling pathway that can regulate the differentiation, self-renewal, and quiescence of HSCs, and many types of molecules can regulate HSCs' these three potentials by influencing the mTOR signaling pathway. Here we review how mTOR signaling pathway regulates HSCs three potentials, and introduce some molecules that can work as the regulator of HSCs' these potentials through the mTOR signaling. Finally, we outline the clinical significance of studying the regulation of HSCs three potentials through the mTOR signaling pathway and make some predictions.

The Management of Low-Risk Myelodysplastic Syndromes-Current Standards and Recent Advances

ABSTRACT

The myelodysplastic syndromes (MDSs) are a heterogeneous group of hematologic neoplasms with varied natural histories and prognoses. Specific to this review, treatment of low-risk MDS most often focuses on improving quality of life by correcting cytopenias, as opposed to urgent disease modification to avoid acute myeloid leukemia. These treatments include transfusion support with iron chelation when necessary, growth factors including novel maturation agents such as luspatercept, lenalidomide for del(5q) disease, and, increasingly, low-dose hypomethylating agents. Recent advances in the understanding of the genetic lesions that drive MDS have prompted a reassessment of how low-risk disease is defined and helped to identify a subset of low-risk MDS patients who may benefit from a more aggressive treatment paradigm, including hematopoietic stem cell transplantation.

Transplant Referral Patterns for Patients with Newly Diagnosed Higher-Risk Myelodysplastic Syndromes and Acute Myeloid Leukemia at Academic and Community Sites in the Connect® Myeloid Disease Registry: Potential Barriers to Care

BACKGROUND

Hematopoietic stem cell transplantation (HCT) is indicated for patients with higher-risk (HR) myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Age, performance status, patient frailty, comorbidities, and non-clinical factors (eg, cost, distance to site) are all recognized as important clinical factors that can influence HCT referral patterns and patient outcomes. However, the proportion of eligible patients referred for HCT in routine clinical practice is largely unknown.

OBJECTIVE

This study aimed to assess patterns of consideration for HCT among patients with HR-MDS and AML enrolled in the Connect® Myeloid Disease Registry, at community/government (CO/GOV)- or academic (AC)-based sites, as well as to identify factors associated with transplant referral rates.

STUDY DESIGN

We assessed patterns of consideration for, and completion of, HCT among patients with HR-MDS and AML enrolled between December 12, 2013 and March 6, 2020 in the Connect® Myeloid Disease Registry at 164 CO/GOV and AC sites. Registry sites recorded whether patients were considered for transplant at baseline and at each follow-up visit. The following answers were possible: "considered potentially eligible", "not considered potentially eligible", or "not assessed". Sites also recorded whether patients subsequently underwent HCT at each follow-up visit. Comparison of transplant consideration rates between CO/GOV and AC sites was performed using multivariable logistic regression analysis with covariates for age and comorbidity.

RESULTS

Among the 778 patients with HR-MDS or AML enrolled in the Registry, patients at CO/GOV sites (27.9%) were less likely to be considered potentially eligible for HCT than patients at AC sites (43.9%; (P < .0001). Multivariable logistic regression analysis with factors for age (<65 versus ≥65 years) and ACE-27 comorbidity grade (<2 versus ≥2) demonstrated that patients at CO/GOV sites were significantly less likely to be considered potentially eligible for transplant than those at AC sites (odds ratio: 1.6, 95% confidence interval [CI], 1.1-2.4, P = .0155). Of patients considered eligible for transplant, 45.1% (65/144) and 35.7% (41/115) of patients at CO/GOV and AC sites, respectively, underwent transplantation (P = .12). Approximately half of all patients at CO/GOV (50.1%) and AC (45.4%) sites were not considered potentially eligible for HCT; the most common reasons were age at CO/GOV sites (71.5%) and comorbidities at AC sites (52.1%). Across all sites, 17.4% of patients across all sites were reported as not assessed (and thus not considered) for transplant by their treating physician (20.7% at CO/GOV and 10.7% at AC sites; P = .0005).

CONCLUSIONS

These findings suggest many patients with HR-MDS and AML who may be candidates for HCT are not receiving assessment or consideration for transplant in clinical practice. In addition, treatment at CO/GOV sites and age are still significant barriers to ensuring all potentially eligible patients are assessed for HCT.

Whole-genome sequencing identifies novel predictors for hematopoietic cell transplant outcomes for patients with myelodysplastic syndrome: a CIBMTR study

Recurrent mutations in TP53, RAS pathway and JAK2 genes were shown to be highly prognostic of allogeneic hematopoietic cell transplant (alloHCT) outcomes in myelodysplastic syndromes (MDS). However, a significant proportion of MDS patients has no such mutations. Whole-genome sequencing (WGS) empowers the discovery of novel prognostic genetic alterations. We conducted WGS on pre-alloHCT whole-blood samples from 494 MDS patients. To nominate genomic candidates and subgroups that are associated with overall survival, we ran genome-wide association tests via gene-based, sliding window and cluster-based multivariate proportional hazard models. We used a random survival forest (RSF) model with build-in cross-validation to develop a prognostic model from identified genomic candidates and subgroups, patient-, disease- and HCT-related clinical factors. Twelve novel regions and three molecular signatures were identified with significant associations to overall survival. Mutations in two novel genes, CHD1 and DDX11, demonstrated a negative impact on survival in AML/MDS and lymphoid cancer data from the Cancer Genome Atlas (TCGA). From unsupervised clustering of recurrent genomic alterations, genomic subgroup with TP53/del5q is characterized with the significant association to inferior overall survival and replicated by an independent dataset. From supervised clustering of all genomic variants, more molecular signatures related to myeloid malignancies are characterized from supervised clustering, including Fc-receptor FCGRs, catenin complex CDHs and B-cell receptor regulators MTUS2/RFTN1. The RSF model with genomic candidates and subgroups, and clinical variables achieved superior performance compared to models that included only clinical variables.

What’s New in the Classification, Diagnosis and Therapy of Myeloid Leukemias

Myeloid leukemias are a broad group of hematological disorders, characterized by heterogeneous clinical and biological features. In recent years, unprecedented genetic discoveries and clinical–biological correlations have revolutionized the field of myeloid leukemias. The most relevant changes have specifically occurred in acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), chronic myeloid leukemia (CML) and myeloid neoplasms (MNs) with eosinophilia. The recently published International Consensus Classification (ICC) of myeloid neoplasms has addressed these changes, providing an updated framework and revised diagnostic criteria for such entities. This is also the aim of the 5th edition of the WHO classification of hematopoietic tumors, whose preliminary version was published in 2022. Parallel to this, new therapeutic options and novel molecular targets have changed the management of many myeloid entities, including AML and CML. This review aims to address the most relevant updates in the classification and diagnosis of AML, CMML, CML and MNs with eosinophilia. The state of the art of treatment and future therapeutic options for such disorders are also discussed.

Current Therapeutic Landscape in Lower Risk Myelodysplastic Syndromes

OPINION STATEMENT

Lower risk myelodysplastic syndromes are typically characterized by an indolent disease course with a relatively low risk of transformation into acute myeloid leukemia. These patients are classically identified using the revised International Prognostic Scoring System and most likely its molecular version in the near future which may change the paradigm of treatment. The overall goals of care are symptomatic control to reduce transfusion requirements and improve quality of life. Symptomatic anemia is the most common indication to initiate disease-specific therapies after the optimization of supportive measures. Currently, erythropoiesis-stimulating agents remain the standard upfront therapy for anemia, and patients with del(5q) cytogenetic changes can benefit from lenalidomide monotherapy. Other therapeutic options after failure of upfront treatment include luspatercept, hypomethylating agents, and immunosuppressive therapies after taking into account of individualized disease features. Allogeneic hematopoietic stem cell transplant is the only potentially curative option and is usually reserved for medically fit patients with severe symptomatic cytopenias who failed all standard options and/or the disease is progressing toward higher risk categories. Fortunately, novel investigational therapies are rapidly emerging by targeting different biological processes contributing to MDS pathogenesis, and eligible patients should be managed in clinical trials if available.

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

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

Therapeutic approaches for the management of higher risk myelodysplastic syndromes

The heterogeneous nature of myelodysplastic syndromes (MDS) demands a risk-adapted therapeutic approach, and higher risk MDS, characterized by an increased risk of transformation into acute myeloid leukemia and inferior survival, is typically defined based on an integrated assessment of cytopenias, bone marrow blast percentage, and cytogenetic findings using the revised International Prognostic Scoring System. Incorporating mutational data could further refine the risk assessment and identify those with higher-than-expected disease risk. The principal therapeutic goal in this disease subset is to modify the natural history and prolong survival. Allogeneic stem cell transplant, the only potentially curative treatment, should be offered to eligible patients. Hypomethylating agents are the only approved treatment with unsatisfactory response rates and duration, and patients who failed prior hypomethylating agents unfortunately have dismal outcomes with urgent need of novel therapeutic agents. In this review, we provide the therapeutic landscape in higher risk MDS based on the current evidence and discuss the investigational treatment options under development.

The effect of granulocyte-colony stimulating factor, decitabine, and busulfan-cyclophosphamide versus busulfan-cyclophosphamide conditioning on relapse in patients with myelodysplastic syndrome or secondary acute myeloid leukaemia evolving from myelodysplastic syndrome undergoing allogeneic haematopoietic stem-cell transplantation: an open-label, multicentre, randomised, phase 3 trial

BACKGROUND

Relapse remains high in patients with myelodysplastic syndrome-refractory anaemia with excess blasts (RAEB) or secondary acute myeloid leukaemia evolving from myelodysplastic syndrome undergoing allogeneic haematopoietic stem-cell transplantation (HSCT). We aimed to investigate whether granulocyte-colony stimulating factor (G-CSF) and decitabine plus busulfan-cyclophosphamide conditioning reduced relapse compared with busulfan-cyclophosphamide in this population.

METHODS

We did an open-label, randomised, phase 3 trial at six hospitals in China. Eligible patients (aged 14-65 years) had myelodysplastic syndrome-RAEB or secondary acute myeloid leukaemia evolving from myelodysplastic syndrome, and an Eastern Cooperative Oncology Group performance status of 0-2 and HSCT comorbidity index of 0-2. Patients were randomly assigned (1:1) to receive G-CSF, decitabine, and busulfan-cyclophosphamide conditioning or busulfan-cyclophosphamide conditioning. Randomisation was done with permuted blocks (block size four) with no stratification and was implemented through an interactive web-based response system, which was independent of study site staff and investigators. G-CSF, decitabine, and busulfan-cyclophosphamide conditioning comprised G-CSF 5 μg/kg daily subcutaneously (days -17 to -10), decitabine 20 mg/m² daily intravenously (days -14 to -10), busulfan 3·2 mg/kg daily intravenously (days -7 to -4), and cyclophosphamide 60 mg/kg daily intravenously (days -3 and -2). Busulfan-cyclophosphamide conditioning comprised the same dose and duration of busulfan and cyclophosphamide. The primary endpoint was 2 year cumulative incidence of relapse. All efficacy and safety endpoints were assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02744742; the trial is complete.

FINDINGS

Between April 18, 2016, and Sept 30, 2019, 297 patients were screened for eligibility, 202 of whom were randomly assigned to G-CSF, decitabine, and busulfan-cyclophosphamide (n=101) or busulfan-cyclophosphamide (n=101) conditioning. 123 (61%) participants were male and 79 (31%) were female. Median follow-up was 32·4 months (IQR 10·0-43·0). The 2-year cumulative incidence of relapse was 10·9% (95% CI 5·8-17·9) in the G-CSF, decitabine, and busulfan-cyclophosphamide group and 24·8% (16·8-33·5) in the busulfan-cyclophosphamide group (hazard ratio 0·39 [95% CI 0·19-0·79]; p=0·011). Within 100 days after transplantation, the most common grade 3-4 adverse events in the G-CSF, decitabine, and busulfan-cyclophosphamide group and the busulfan-cyclophosphamide group were infections (34 [34%] and 32 [32%]), acute graft-versus-host disease (30 [30%] and 30 [30%]), and gastrointestinal toxicity (28 [28%] and 29 [29%]). 11 (11%) patients in the G-CSF, decitabine, and busulfan-cyclophosphamide group and 13 (13%) in the busulfan-cyclophosphamide group died of adverse events. There were no treatment related deaths.

INTERPRETATION

Our results suggest that G-CSF, decitabine, and busulfan-cyclophosphamide conditioning is a better choice than busulfan-cyclophosphamide conditioning for patients with myelodysplastic syndrome-RAEB or secondary acute myeloid leukaemia evolving from myelodysplastic syndrome undergoing allogeneic HSCT. This conditioning could be a suitable therapuetic option for this patient population.

FUNDING

None.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Allogeneic stem cell transplantation without preconditioning in a child with therapy-related myelodysplastic syndrome: A case report

RATIONALE

Infants with mixed-lineage leukemia (MLL)-rearranged leukemia are usually refractory to standard induction therapy and are not immediate candidates for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Chromosome 11q23 translocations, resulting in MLL rearrangement, have been well characterized in infant acute lymphoblastic leukemia (ALL). While t(4;11) ALL continues to have carry a bleak prognosis, patients with therapy-related myelodysplastic syndrome (t-MDS) have a shorter median overall survival than those compared with de novo MDS.

PATIENT CONCERNS

We describe a child with t-MDS who evolved from MLL-rearranged ALL and was successfully treated with HSCT without toxic preconditioning.

DIAGNOSES

MDS diagnosis was based on morphological characteristics of bone marrow dysplasia in patients with clinical manifestations evidence of hematopoiesis impairments by different combinations of anemia, leukopenia, neutropenia, and thrombocytopenia.

INTERVENTIONS

Although the best donor for allo-HSCT is generally considered an human leukocyte antigen-matched sibling, only ~ 30% of patients have a suitable sibling. HSCT from an unrelated donor is a suitable option for patients with t-MDS who do not have matched sibling donors.

OUTCOMES

Allo-HSCT without recipient preconditioning could be a promising treatment option for t-MDS, especially for patients with recurrent or persistent infections.

LESSONS

Cytogenetics, prognosis, and treatment of t-MDS are briefly discussed. Preconditioning before allo-HSCT seriously damages immune function. This work reviews our experience with a patient with t-MDS following ALL complicated by recurrent infections, and highlights our choice to omit preconditioning from allo-HSCT.

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.

Identifying the optimal conditioning intensity for stem cell transplantation in patients with myelodysplastic syndrome: a machine learning analysis

A conditioning regimen is an essential prerequisite of allogeneic hematopoietic stem cell transplantation for patients with myelodysplastic syndrome (MDS). However, the optimal conditioning intensity for a patient may be difficult to establish. This study aimed to identify optimal conditioning intensity (reduced-intensity conditioning regimen [RIC] or myeloablative conditioning regimen [MAC]) for patients with MDS. Overall, 2567 patients with MDS who received their first HCT between 2009 and 2019 were retrospectively analyzed. They were divided into a training cohort and a validation cohort. Using a machine learning-based model, we developed a benefit score for RIC in the training cohort. The validation cohort was divided into a high-score and a low-score group, based on the median benefit score. The endpoint was progression-free survival (PFS). The benefit score for RIC was developed from nine baseline variables in the training cohort. In the validation cohort, the hazard ratios of the PFS in the RIC group compared to the MAC group were 0.65 (95% confidence interval [CI]: 0.48-0.90, P = 0.009) in the high-score group and 1.36 (95% CI: 1.06-1.75, P = 0.017) in the low-score group (P for interaction < 0.001). Machine-learning-based scoring can be useful for the identification of optimal conditioning regimens for patients with MDS.

Allogeneic stem cell transplantation for patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogenous group of clonal hematopoietic stem cell neoplasms primarily affecting older persons, associated with dysplastic changes of bone marrow cells, peripheral cytopenias, and various risk of leukemic transformation. Although treatment with several drugs has shown improved disease control, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment for MDS. The number of patients receiving a transplant, as well as survival, have increased past years because of the use of reduce-intensity conditioning regimens (RIC) as well as the use of haploidentical donors for transplantation. With treatment-related mortality as main limitation, pre-transplant evaluation is essential to assess risks for this older group of patients. In a recent randomized study, allo-HSCT with RIC for patients >50 years old with higher-risk MDS demonstrated superiority in survival compared with hypomethylating agents. Genetic mutations have been shown to significantly impact treatment outcomes including after transplant. Recently, a transplant-specific risk score (which includes age, donor type, performance status, cytogenetic category, recipient's cytomegalovirus status, percentage of blasts, and platelet count) has shown superiority in transplantation outcome prediction, compared with previous scoring systems. Survival remains low for most patients with TP53 mutations and novel treatment strategies are needed, such as administration of natural killer cells post-transplant, as there is no clear evidence that maintenance therapy after transplantation can improve outcomes.

Impact of treatments before allogeneic hematopoietic stem cell transplantation in patients with higher-risk myelodysplastic syndrome

OBJECTIVE

The study aimed to evaluate pre-allogeneic hematopoietic stem cell transplantation (allo-HSCT) treatment, compare the endpoints related to disease management between pre-HSCT cytoreduction patients and upfront transplantation patients with higher-risk myelodysplastic syndrome (MDS).

METHODS

A total of 90 higher-risk MDS patients administered allo-HSCT in the Hematology Department of the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed, which included 28 patients with upfront transplantation and 62 patients with pre-transplant cytoreduction, including 30 patients received hypomethylating agents (HMA) and 32 patients received hypomethylating agents and induction chemotherapy (HMA+IC). Difference between the two groups regarding hematopoietic reconstruction, graft-versus-host disease (GVHD), relapse rate, non-relapse death (NRM), overall survival (OS) and relapse-free survival (RFS) was compared.

RESULTS

No significant differences in OS, DFS and NRM were found between the upfront transplantation and pre-transplant cytoreduction groups, and cumulative cGVHD occurrence and relapse rates were 35.7 % and 14.5 % (P = 0.029), and 10.7 % and 12.9 % (p = 0.535), respectively. Survival rates were significantly higher in the upfront transplantation and HMA+IC groups compared with the HMA group (3-year OS: 67.9 %, 68.8 %, 43.3 %, P = 0.039; 3-year RFS: 64.3 %, 62.5 %, 43.3 %, P = 0.107; 3-year NRM: 25.0 %, 21.9 %, 50.0 %, P = 0.025). Compared with the upfront transplantation group, overall response to cytoreductive therapy (OR) and non-response to cytoreductive therapy (NR), 3-year OS were 67.9 %, 73.0 % and 32.0 % (P < 0.001), 3-year RFS were 64.3 %, 73.0 % and 24.0 % (P < 0.001) and 3-year NRM were 25.0 %, 21.6 %, and 56.0 %, respectively (P < 0.001). Upfront transplantation (n = 11) had better OS and RFS compared with the cytoreductive group (n = 10) in patients with ≥ 10 % bone marrow blast cells before transplantation (3-year OS: 63.64 %, 22.22 %, p = 0.010; 3-year DFS: 63.64 %, 20.00 %, p = 0.012, respectively).

CONCLUSION

The pre-transplant treatment regimen was an independent prognostic factor of OS and NRM. If the donor is suitable, upfront transplantation may provide longer survival in higher-risk MDS patients, which, however, may also increase the incidence of cGVHD. Even in patients with bone marrow blast cells ≥ 10 % before transplantation, upfront transplantation was not worse than transplantation after cytoreductive therapy. While waiting for a transplant, HMA+IC therapy may be a good pre-transplant treatment option.

Splicing factor mutations in the myelodysplastic syndromes: Role of key aberrantly spliced genes in disease pathophysiology and treatment

Mutations of splicing factor genes (including SF3B1, SRSF2, U2AF1 and ZRSR2) occur in more than half of all patients with myelodysplastic syndromes (MDS), a heterogeneous group of myeloid neoplasms. Splicing factor mutations lead to aberrant pre-mRNA splicing of many genes, some of which have been shown in functional studies to impact on hematopoiesis and to contribute to the MDS phenotype. This clearly demonstrates that impaired spliceosome function plays an important role in MDS pathophysiology. Recent studies that harnessed the power of induced pluripotent stem cell (iPSC) and CRISPR/Cas9 gene editing technologies to generate new iPSC-based models of splicing factor mutant MDS, have further illuminated the role of key downstream target genes. The aberrantly spliced genes and the dysregulated pathways associated with splicing factor mutations in MDS represent potential new therapeutic targets. Emerging data has shown that IRAK4 is aberrantly spliced in SF3B1 and U2AF1 mutant MDS, leading to hyperactivation of NF-κB signaling. Pharmacological inhibition of IRAK4 has shown efficacy in pre-clinical studies and in MDS clinical trials, with higher response rates in patients with splicing factor mutations. Our increasing knowledge of the effects of splicing factor mutations in MDS is leading to the development of new treatments that may benefit patients harboring these mutations.

Management of patients with lower-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic stem cell disorders characterized by ineffective hematopoiesis with abnormal blood cell development (dysplasia) leading to cytopenias and an increased risk for progression to acute myeloid leukemia (AML). Patients with MDS can generally be classified as lower- (LR-MDS) or higher-risk (HR-MDS). As treatment goals for patients with LR-MDS and those with HR-MDS differ significantly, appropriate diagnosis, classification, and follow-up are critical for correct disease management. In this review, we focus on the diagnosis, prognosis, and treatment options, as well as the prediction of the disease course and monitoring of treatment response in patients with LR-MDS. We discuss how next-generation sequencing, increasing knowledge on mechanisms of MDS pathogenesis, and novel therapies may change the current treatment landscape in LR-MDS and why structured assessments of responses, toxicities, and patient-reported outcomes should be incorporated into routine clinical practice.