Prognostic Mutations in Myelodysplastic Syndrome after Stem-Cell Transplantation

Lenalidomide promotes the development of TP53-mutated therapy-related myeloid neoplasms

There is a growing body of evidence that therapy-related myeloid neoplasms (t-MNs) with driver gene mutations arise in the background of clonal hematopoiesis (CH) under the positive selective pressure of chemo- and radiation therapies. Uncovering the exposure relationships that provide selective advantage to specific CH mutations is critical to understanding the pathogenesis and etiology of t-MNs. In a systematic analysis of 416 patients with t-MN and detailed prior exposure history, we found that TP53 mutations were significantly associated with prior treatment with thalidomide analogs, specifically lenalidomide. We demonstrated experimentally that lenalidomide treatment provides a selective advantage to Trp53-mutant hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, the effect of which was specific to Trp53-mutant HSPCs and was not observed in HSPCs with other CH mutations. Because of the differences in CK1α degradation, pomalidomide treatment did not provide an equivalent level of selective advantage to Trp53-mutant HSPCs, providing a biological rationale for its use in patients at high risk for t-MN. These findings highlight the role of lenalidomide treatment in promoting TP53-mutated t-MNs and offer a potential alternative strategy to mitigate the risk of t-MN development.

Novel Therapies for Unmet Clinical Needs in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a very heterogeneous disease, with extremely variable clinical features and outcomes. Current management relies on risk stratification based on IPSS and IPSS-R, which categorizes patients into low (LR-) and high-risk (HR-) MDS. Therapeutic strategies in LR-MDS patients mainly consist of erythropoiesis stimulating agents (ESAs), transfusion support, and luspatercept or lenalidomide for selected patients. Current unmet needs include the limited options available after treatment failure, and the consequent transfusion burden with several hospital admissions and poor quality of life. Therapeutic approaches in HR-MDS patients are aimed at changing the natural course of the disease and hypometylating agents (HMA) are the first choice. The only potentially curative treatment is allogeneic stem cell transplant (allo-HCT), restricted to a minority of young and fit candidates. Patients unfit for or those that relapse after the abovementioned options harbor an adverse prognosis, with limited overall survival and frequent leukemic evolution. Recent advances in genetic mutations and intracellular pathways that are relevant for MDS pathogenesis are improving disease risk stratification and highlighting therapeutic targets addressed by novel agents. Several drugs are under evaluation for LR and HR patients, which differ by their mechanism of action, reported efficacy, and phase of development. This review analyzes the current unmet clinical needs for MDS patients and provides a critical overview of the novel agents under development in this setting.

Stem Cell Transplantation in Patients Affected by Shwachman-Diamond Syndrome: Expert Consensus and Recommendations From the EBMT Severe Aplastic Anaemia Working Party

Shwachman-Diamond syndrome is a rare disorder that can develop malignant and nonmalignant hematological complications. Overall, 10% to 20% of Shwachman-Diamond patients need hematopoietic stem cell transplantation (HSCT), but most centers have a limited experience and different approaches. The European Society for Blood and Marrow Transplantation-Severe Aplastic Anaemia Working Party promoted an expert consensus to propose recommendations regarding key issues in the management of Shwachman-Diamond patients with hematological complications. The main items identified as relevant for improving survival were: the importance of regular and structured hematologic follow-up, the potential reduction of transplant-related mortality by using reduced-intensity conditioning regimens, the limitation of total body irradiation, particularly for non-malignant severe cytopenia/bone marrow failure, the early diagnosis of clonal malignant evolution and early recognition of an indication for HSCT. Finally, the poor results of HSCT in patients with acute myeloid leukemia, irrespective of cytoreductive chemotherapy treatment received prior to transplantation, highlights the need for innovative approaches. © 2023 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Dose-finding trial of azacitidine as post-transplant maintenance for high-risk MDS: a KSGCT prospective study

This 3+3 dose-escalation phase I multicenter study investigated the optimal dose of azacitidine (AZA) for post-hematopoietic stem cell transplantation (HSCT) maintenance, which remains unknown in Japan. Recipients of a first HSCT for high-risk myelodysplastic syndromes (MDS, n = 12) or acute myeloid leukemia (AML) with antecedent MDS (n = 3) received post-HSCT AZA maintenance in 2015-2019. The optimal AZA dose was defined as the dose at which 50-70% of patients can complete four cycles without dose-limiting toxicity (DLT). The initial dose level 1 was set as 30 mg/m² for 5 days per 28-day cycle, and dose levels 0, 2, and 3 were set as 20, 40, and 50 mg/m². DLT was defined as any grade 3 non-hematological or grade 4 hematological toxicity. The 15 evaluable patients were 55 (37-64) years old. The median observation of the post-HSCT survivors was 935 (493-1915) days. The median number of days post-HSCT to the start of AZA was 101 (59-176). In the first, second, and third cohorts, five of nine patients completed four cycles at dose level 1. In the final cohort, five of six additional patients completed at the same dose. In total, 10 (67%) patients tolerated AZA 30 mg/m², which was determined as optimal. DLT occurred in five cases: grade 3 hepatotoxicity, pneumonia, enterocolitis, and grade 4 thrombocytopenia and neutropenia. The 2-year overall survival and disease-free survival rates post-HSCT were 77.0% and 73.3%. Post-HSCT AZA maintenance was well-tolerated and merits further evaluation for patients with MDS or AML with antecedent MDS. Trial registration: UMIN000018791.

How I Treat TP53-Mutated Acute Myeloid Leukemia and Myelodysplastic Syndromes

TP53-mutated acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are among the myeloid malignancies with the poorest prognosis. In this review, we analyze the prognosis of these two diseases, focussing particularly on the extent of the mono or biallelic mutation status of TP53 mutation, which is largely correlated with cytogenetic complexity. We discuss the possible/potential improvement in outcome based on recent results obtained with new drugs (especially eprenetapopt and magrolimab). We also focus on the impact of allogeneic hematopoietic stem cell transplantation (aHSCT) including post aHSCT treatment.

PPM1D in Solid and Hematologic Malignancies: Friend and Foe?

In the face of constant genomic insults, the DNA damage response (DDR) is initiated to preserve genome integrity; its disruption is a classic hallmark of cancer. Protein phosphatase Mg2+/Mn2+-dependent 1D (PPM1D) is a central negative regulator of the DDR that is mutated or amplified in many solid cancers. PPM1D overexpression is associated with increased proliferative and metastatic behavior in multiple solid tumor types and patients with PPM1D-mutated malignancies have poorer prognoses. Recent findings have sparked an interest in the role of PPM1D in hematologic malignancies. Acquired somatic mutations may provide hematopoietic stem cells with a competitive advantage, leading to a substantial proportion of mutant progeny in the peripheral blood, an age-associated phenomenon termed "clonal hematopoiesis" (CH). Recent large-scale genomic studies have identified PPM1D to be among the most frequently mutated genes found in individuals with CH. While PPM1D mutations are particularly enriched in patients with therapy-related myeloid neoplasms, their role in driving leukemic transformation remains uncertain. Here, we examine the mechanisms through which PPM1D overexpression or mutation may drive malignancy by suppression of DNA repair, cell-cycle arrest, and apoptosis. We also discuss the divergent roles of PPM1D in the oncogenesis of solid versus hematologic cancers with a view to clinical implications and new therapeutic avenues.

Disease-related thrombocytopenia in myelofibrosis is defined by distinct genetic etiologies and is associated with unique prognostic correlates

BACKGROUND

Thrombocytopenia in patients with myelofibrosis (MF) is prognostically detrimental and poses a therapeutic challenge. MF patients with thrombocytopenia are considered high-risk by most prognostic models and their distinct phenotype has given rise to the emerging concept of cytopenic MF. Yet, the mechanisms underlying thrombocytopenia in MF are poorly understood.

METHODS

This study aimed to highlight the genetic mechanisms driving low platelet counts in treatment-naive MF patients, establish their phenotypic correlates, and assess prognostic factors specific to this group of patients.

RESULTS

The authors found that most patients presenting with low platelets had a clear thrombocytopenia-specific genetic abnormality involving a U2AF1 Q157 mutation, deletion 20q, molecular complexity (three or more mutations), or high-risk karyotype. Etiologic clustering did not correlate with prognosis; however, thrombocytopenic patients were found to have unique prognostic variables including low serum albumin and mutations of SRSF2 and TP53. This led to the proposal of a prognostic model (SRSF2, albumin, TP53 score) that stratifies thrombocytopenic patients as low, intermediate, or high-risk with corresponding median survivals of 93.5, 29.5, and 7.2 months, respectively.

CONCLUSIONS

This study demonstrates that thrombocytopenia in MF is driven by different genetic mechanisms and is not uniformly high-risk. As novel agents with improved hematologic safety profiles enter the treatment landscape, thoughtful, risk-adapted therapeutic decisions will be required for MF patients with thrombocytopenia.

LAY SUMMARY

A significant minority of patients with myelofibrosis (MF) present with low platelets. Historically, these patients have been viewed as having "high-risk" disease, but this may not be uniformly true. Our study shows that there are various different causes for low platelets in MF, some of which represent high-risk disease whereas others do not. Additionally, our study shows that genetic mutations affecting the genes SRSF2 and TP53 are uniquely problematic in this group, as is a low serum albumin level. This study helps to risk-stratify MF patients with thrombocytopenia, thereby providing more information to guide informed and individualized treatment decisions.

Additional cytogenetic features determine outcome in patients allografted for TP53 mutant acute myeloid leukemia

BACKGROUND

The presence of TP53 mutations is associated with an unfavorable outcome in patients allografted for acute myeloid leukemia (AML), leading some to question the benefit of an allogeneic stem cell transplantation (allo-SCT) for this patient group, although this has not been studied in a large cohort.

METHODS

A total of 780 patients with AML in first complete remission, with either intermediate- or adverse-risk cytogenetics, whose TP53 mutation status was reported, were included in this study from the European Society for Blood and Marrow Transplantation.

RESULTS

Two-year overall survival (OS) was impaired in patients (n = 179) with evidence of a TP53 mutation at diagnosis (35.1%; 95% confidence interval [CI], 26.7-43.7) as compared to the cohort without (n = 601) (64%; 95% CI, 59.1-68.4; P = .001). In patients with mutant TP53 AML with no evidence of either chromosome 17p loss (17p-) and/or complex karyotype (CK) (n = 53, 29.6%), 2-year OS was 65.2% (95% CI, 48.4-77.6). This was not significantly different to patients without TP53 mutations. In patients with mutant TP53 AML with either 17p- and/or CK (n = 126, 70.4%), the OS was lower (24.6%; 95% CI, 16.2-34; P = .001).

CONCLUSIONS

In summary, the adverse prognostic effect of TP53 mutations in AML following an allo-SCT is not evident in patients with neither co-occurring 17p- and/or CK, and these data inform decisions regarding allo-SCT in patients with TP53 mutant AML.

Allogeneic haematopoietic stem cell transplantation with decitabine-containing preconditioning regimen in TP53-mutant myelodysplastic syndromes: A case study

Myelodysplastic syndrome (MDS) with TP53 mutations has a poor prognosis after transplantation, and novel therapeutic means are urgently needed. Decitabine (Dec) monotherapy has demonstrated improved overall response rates in MDS and acute myeloid leukaemia, although these responses were not durable. This study aimed to preliminary evaluate the efficacy of a Dec-containing allogeneic haematopoietic stem cell transplantation (allo-HSCT) preconditioning regimen in TP53-mutant MDS. Nine patients with TP53-mutant myelodysplastic syndromes received the decitabine-containing preconditioning regimen and subsequent myeloablative allo-HCT between April 2013 and September 2021 in different centres. At a median follow-up of 42 months (range, 5 to 61 months), the overall survival (OS) was 89% (8/9), progression-free survival (PFS) was 89% (8/9), and relapse incidence was 11.1%. The incidence of severe acute (grade III-IV) graft-versus-host disease (GVHD) was 22.2% (2/9) and that of chronic moderate-to-severe GVHD was 11.1% (1/9). The 1-year GVHD-free/relapse-free survival (GRFS) was 56% (5/9). In conclusion, we found real-world clinical data that supports the use of a Dec-containing preconditioning regimen before allo-HSCT for possible improved outcomes in TP53-mutant MDS patients; there is therefore an urgent call for an in-depth exploration of the involved mechanism to confirm these preliminary findings.

TP53 copy number and protein expression inform mutation status across risk categories in acute myeloid leukemia

Mutant TP53 is an adverse risk factor in acute myeloid leukemia (AML), but large-scale integrated genomic-proteomic analyses of TP53 alterations in patients with AML remain limited. We analyzed TP53 mutational status, copy number (CN), and protein expression data in AML (N = 528) and provide a compilation of mutation sites and types across disease subgroups among treated and untreated patients. Our analysis shows differential hotspots in subsets of AML and uncovers novel pathogenic variants involving TP53 splice sites. In addition, we identified TP53 CN loss in 70.2% of TP53-mutated AML cases, which have more deleterious TP53 mutations, as well as copy neutral loss of heterozygosity in 5/32 (15.6%) AML patients who had intact TP53 CN. Importantly, we demonstrate that mutant p53 protein expression patterns by immunohistochemistry evaluated using digital image-assisted analysis provide a robust readout that integrates TP53 mutation and allelic states in patients with AML. Expression of p53 by immunohistochemistry informed mutation status irrespective of TP53 CN status. Genomic analysis of comutations in TP53-mutant AML shows a muted landscape encompassing primarily mutations in genes involved in epigenetic regulation (DNMT3A and TET2), RAS/MAPK signaling (NF1, KRAS/NRAS, PTPN11), and RNA splicing (SRSF2). In summary, our data provide a rationale to refine risk stratification of patients with AML on the basis of integrated molecular and protein-level TP53 analyses.

Molecular International Prognostic Scoring System for Myelodysplastic Syndromes

BACKGROUND: Risk stratification and therapeutic decision-making for myelodysplastic syndromes (MDS) are based on the International Prognostic Scoring System–Revised (IPSS-R), which considers hematologic parameters and cytogenetic abnormalities. Somatic gene mutations are not yet used in the risk stratification of patients with MDS. METHODS: To develop a clinical-molecular prognostic model (IPSS-Molecular [IPSS-M]), pretreatment diagnostic or peridiagnostic samples from 2957 patients with MDS were profiled for mutations in 152 genes. Clinical and molecular variables were evaluated for associations with leukemia-free survival, leukemic transformation, and overall survival. Feature selection was applied to determine the set of independent IPSS-M prognostic variables. The relative weights of the selected variables were estimated using a robust Cox multivariable model adjusted for confounders. The IPSS-M was validated in an external cohort of 754 Japanese patients with MDS. RESULTS: We mapped at least one oncogenic genomic alteration in 94% of patients with MDS. Multivariable analysis identified TP53multihit, FLT3 mutations, and MLLPTD as top genetic predictors of adverse outcomes. Conversely, SF3B1 mutations were associated with favorable outcomes, but this was modulated by patterns of comutation. Using hematologic parameters, cytogenetic abnormalities, and somatic mutations of 31 genes, the IPSS-M resulted in a unique risk score for individual patients. We further derived six IPSS-M risk categories with prognostic differences. Compared with the IPSS-R, the IPSS-M improved prognostic discrimination across all clinical end points and restratified 46% of patients. The IPSS-M was applicable in primary and secondary/therapy-related MDS. To simplify clinical use of the IPSS-M, we developed an open-access Web calculator that accounts for missing values. CONCLUSIONS: Combining genomic profiling with hematologic and cytogenetic parameters, the IPSS-M improves the risk stratification of patients with MDS and represents a valuable tool for clinical decision-making. (Funded by Celgene Corporation through the MDS Foundation, the Josie Robertson Investigators Program, the Edward P. Evans Foundation, the Projects of National Relevance of the Italian Ministry of University and Research, Associazione Italiana per la Ricerca sul Cancro, the Japan Agency for Medical Research and Development, Cancer Research UK, the Austrian Science Fund, the MEXT [Japanese Ministry of Education, Culture, Sports, Science and Technology] Program for Promoting Research on the Supercomputer Fugaku, the Japan Society for the Promotion of Science, the Taiwan Department of Health, and Celgene Corporation through the MDS Foundation.)

Therapeutic Outcomes and Prognostic Impact of Gene Mutations Including TP53 and SF3B1 in Patients with Del(5q) Myelodysplastic Syndromes (MDS)

BACKGROUND

Genetic alterations are increasingly being recognized to play an important role in both diagnosis and prognosis of MDS. In general, MDS patients with SF3B1 mutations (MT) are known to have favorable outcomes whereas those with TP53 mutations have dismal survivals. However, it is unclear if the impact of these mutations applies to all subtypes of MDS including del(5q) which is known for its response to lenalidomide and better prognosis.

MATERIALS AND METHODS

We retrospectively reviewed 132 del(5q) MDS patients who were treated at the Moffitt Cancer Center (2001-2019).

RESULTS

Among patients who received lenalidomide (n = 98), 50%, 42.9%, and 7.1% achieved hematologic improvement or better, no response, and disease progression/death with a median overall survival (mOS) of 93.2, 72.4, and 25.6 months, respectively (P < .0001). The mOS was 73.3 months but only 25.6 months after patients stopped lenalidomide. TP53 was the most common mutation accounting for 23.8% of the patients. Of the 63 patients with molecular data available, 23.8% harbored TP53 MT and 10% with SF3B1 MT. TP53 status did not impact OS (MT 86.4 vs. wild-type (WT) 73.3 months; P = .72) but those with SF3B1 mutations had a significantly shorter mOS compared to WT (23.9 vs. 83.5 months; P = .001). Multivariate analysis confirmed lenalidomide response and SF3B1 mutations are independently associated with outcomes.

CONCLUSION

Our findings indicate many del(5q) MDS patients will benefit from lenalidomide but survival after its failure is limited. Mutations known to have prognostic impact in MDS at large may not have the same implications in the del(5q) subset.

Allosteric inhibition of PPM1D serine/threonine phosphatase via an altered conformational state

PPM1D encodes a serine/threonine phosphatase that regulates numerous pathways including the DNA damage response and p53. Activating mutations and amplification of PPM1D are found across numerous cancer types. GSK2830371 is a potent and selective allosteric inhibitor of PPM1D, but its mechanism of binding and inhibition of catalytic activity are unknown. Here we use computational, biochemical and functional genetic studies to elucidate the molecular basis of GSK2830371 activity. These data confirm that GSK2830371 binds an allosteric site of PPM1D with high affinity. By further incorporating data from hydrogen deuterium exchange mass spectrometry and sedimentation velocity analytical ultracentrifugation, we demonstrate that PPM1D exists in an equilibrium between two conformations that are defined by the movement of the flap domain, which is required for substrate recognition. A hinge region was identified that is critical for switching between the two conformations and was directly implicated in the high-affinity binding of GSK2830371 to PPM1D. We propose that the two conformations represent active and inactive forms of the protein reflected by the position of the flap, and that binding of GSK2830371 shifts the equilibrium to the inactive form. Finally, we found that C-terminal truncating mutations proximal to residue 400 result in destabilization of the protein via loss of a stabilizing N- and C-terminal interaction, consistent with the observation from human genetic data that nearly all PPM1D mutations in cancer are truncating and occur distal to residue 400. Taken together, our findings elucidate the mechanism by which binding of a small molecule to an allosteric site of PPM1D inhibits its activity and provides insights into the biology of PPM1D.

Comprehensive Validation of Diagnostic Next-Generation Sequencing Panels for Acute Myeloid Leukemia Patients

Next-generation sequencing has greatly advanced the molecular diagnostics of malignant hematological diseases and provides useful information for clinical decision making. Studies have shown that certain mutations are associated with prognosis and have a direct impact on treatment of affected patients. Therefore, reliable detection of pathogenic variants is critically important. In this study, we aimed to compare four sequencing panels with different characteristics, from number of genes covered to technical aspects of library preparation and data analysis workflows, to find the panel with the best clinical utility for myeloid neoplasms with a special focus on acute myeloid leukemia. Using the Acrometrix Oncology Hotspot Control DNA and DNA from acute myeloid leukemia patients, we evaluated panel performance in terms of coverage, precision, recall, and reproducibility and tested different bioinformatics tools that can be used for the evaluation of any next-generation sequencing panel. Taken together, our results support the reliability of the Acrometrix Oncology Hotspot Control to validate and compare sequencing panels for hematological diseases and show which panel-software combination (platform) has the best performance.

Impact of diagnostic genetics on remission MRD and transplantation outcomes in older patients with AML

Older patients with acute myeloid leukemia (AML) have high relapse risk and poor survival after allogeneic hematopoietic cell transplantation (HCT). Younger patients may receive myeloablative conditioning to mitigate relapse risk associated with high-risk genetics or measurable residual disease (MRD), but older adults typically receive reduced-intensity conditioning (RIC) to limit toxicity. To identify factors that drive HCT outcomes in older patients, we performed targeted mutational analysis (variant allele fraction ≥2%) on diagnostic samples from 295 patients with AML aged ≥60 years who underwent HCT in first complete remission, 91% of whom received RIC, and targeted duplex sequencing at remission in a subset comprising 192 patients. In a multivariable model for leukemia-free survival (LFS) including baseline genetic and clinical variables, we defined patients with low (3-year LFS, 85%), intermediate (55%), high (35%), and very high (7%) risk. Before HCT, 79.7% of patients had persistent baseline mutations, including 18.3% with only DNMT3A or TET2 (DT) mutations and 61.4% with other mutations (MRD positive). In univariable analysis, MRD positivity was associated with increased relapse and inferior LFS, compared with DT and MRD-negative mutations. However, in a multivariable model accounting for baseline risk, MRD positivity had no independent impact on LFS, most likely because of its significant association with diagnostic genetic characteristics, including MDS-associated gene mutations, TP53 mutations, and high-risk karyotype. In summary, molecular associations with MRD positivity and transplant outcomes in older patients with AML are driven primarily by baseline genetics, not by mutations present in remission. In this group of patients, where high-intensity conditioning carries substantial risk of toxicity, alternative approaches to mitigating MRD-associated relapse risk are needed.

Clonal hematopoiesis: Mutation-specific adaptation to environmental change

Clonal hematopoiesis of indeterminate potential (CHIP) describes a widespread expansion of genetically variant hematopoietic cells that increases exponentially with age and is associated with increased risks of cancers, cardiovascular disease, and other maladies. Here, we discuss how environmental contexts associated with CHIP, such as old age, infections, chemotherapy, or cigarette smoking, alter tissue microenvironments to facilitate the selection and expansion of specific CHIP mutant clones. Further, we consider major remaining gaps in knowledge, including intrinsic effects, clone size thresholds, and factors affecting clonal competition, that will determine future application of this field in transplant and preventive medicine.

Clinical risk factors for patients with myelodysplastic syndromes undergoing allogeneic hematopoietic stem cell transplantation

Objectives: Allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only curative treatment for myelodysplastic syndromes (MDS), although predicting post-transplant outcomes remains inconclusive. This study evaluated patients who underwent allo-HCT for MDS to identify prognostic factors and develop a clinical risk model.Methods: We evaluated 55 patients between June 2000 and March 2015 to identify prognostic factors and develop a model for three-year overall survival (OS) and event-free survival (EFS). Cox regression analysis was performed on four factors: age ≥55 years; Hematopoietic Cell Transplant-Comorbidity Index >2; intermediate or worse cytogenetic status based on revised International Prognostic Scoring System; and unrelated donor status associated with poor OS in the univariate analysis. A clinical risk model was constructed using the sum of the regression coefficients and evaluated using receiver operating characteristic analysis and five-fold cross-validation.Results: Patient median age was 51 (range: 30-67) years. Median follow-up was 45.8 (range: 1.27-193) months; the three-year OS and EFS rates were 61.8% and 56.4%, respectively. The areas under the curves (AUCs) for OS and EFS were 0.738 and 0.778, respectively, and the average AUC for 50 times five-fold cross-validation were 0.711 and 0.723 for three-year OS and EFS, respectively.Conclusion: A four-clinical-risk-factor model that could effectively predict post-transplantation outcomes and help decision-making in MDS treatment was developed.

Selinexor synergizes with azacitidine to eliminate myelodysplastic syndrome cells through p53 nuclear accumulation

Myelodysplastic syndromes (MDS) are clonal malignancies of multipotent hematopoietic stem cells, characterized by ineffective hematopoiesis leading to cytopenia. Hypomethylating agents, including azacitidine, have been used for treating MDS with some success; however, the overall survival rate remains poor and, therefore, finding new therapies is necessary. Selinexor, which exerts anticancer effects against some hematologic tumors, is a nuclear export protein inhibitor that blocks cell proliferation and induces apoptosis in various cancer cell lines. We investigated the effects of combined selinexor and azacitidine administration on two MDS cell lines, namely SKM-1 and MUTZ-1. Cells were subjected to a proliferation assay, and the effects of each drug alone, and in combination, were compared. Changes in apoptosis and the cell cycle between groups were also analyzed. Western blotting was conducted to identify the underlying mechanism of action of combined selinexor and azacitidine therapy. The results revealed that the combination of selinexor and azacitidine synergistically inhibited MDS cell proliferation and arrested the cell cycle at the G2/M phase. This combination also promoted MDS cell apoptosis and enhanced p53 accumulation in the nucleus, thereby allowing p53 to be activated and to function as a tumor suppressor. Overall, our results indicate that the combination of selinexor and azacitidine may be a promising approach for treating MDS.

Prediction of life-threatening and disabling bleeding in patients with AML receiving intensive induction chemotherapy

Bleeding in patients with acute myeloid leukemia (AML) receiving intensive induction chemotherapy is multifactorial and contributes to early death. We sought to define the incidence and risk factors of grade 4 bleeding to support strategies for risk mitigation. Bleeding events were retrospectively assessed between day-14 and day +60 of induction treatment according to the World Health Organization (WHO) bleeding assessment scale, which includes grade 4 bleeding as fatal, life-threatening, retinal with visual impairment, or involving the central nervous system. Predictors were considered pretreatment or prior to grade 4 bleeding. Using multivariable competing-risk regression analysis with grade 4 bleeding as the primary outcome, we identified risk factors in the development cohort (n = 341), which were tested in an independent cohort (n = 143). Grade 4 bleeding occurred in 5.9% and 9.8% of patients in the development and validation cohort, respectively. Risk factors that were independently associated with grade 4 bleeding included baseline platelet count ≤40 × 109/L compared with >40 × 109/L, and baseline international normalized ratio of prothrombin time (PT-INR) >1.5 or 1.3 > 1.5 compared with ≤1.3. These variables were allocated points, which allowed for stratification of patients with low- and high-risk for grade 4 bleeding. Cumulative incidence of grade 4 bleeding at day+60 was significantly higher among patients with high- vs low-risk (development: 31 ± 7% vs 2 ± 1%; P < .001; validation: 25 ± 9% vs 7 ± 2%; P = .008). In both cohorts, high bleeding risk was associated with disseminated intravascular coagulation (DIC) and proliferative disease. We developed and validated a simple risk model for grade 4 bleeding, which enables the development of rational risk mitigation strategies to improve early mortality of intensive induction treatment.

Association of Clonal Hematopoiesis of Indeterminate Potential with Worse Kidney Function and Anemia in Two Cohorts of Patients with Advanced Chronic Kidney Disease

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) is an inflammatory premalignant disorder resulting from acquired genetic mutations in hematopoietic stem cells. This condition is common in aging populations and associated with cardiovascular morbidity and overall mortality, but its role in CKD is unknown.

METHODS

We performed targeted sequencing to detect CHIP mutations in two independent cohorts of 87 and 85 adults with an eGFR<60 ml/min per 1.73m2. We also assessed kidney function, hematologic, and mineral bone disease parameters cross-sectionally at baseline, and collected creatinine measurements over the following 5-year period.

RESULTS

At baseline, CHIP was detected in 18 of 87 (21%) and 25 of 85 (29%) cohort participants. Participants with CHIP were at higher risk of kidney failure, as predicted by the Kidney Failure Risk Equation (KFRE), compared with those without CHIP. Individuals with CHIP manifested a 2.2-fold increased risk of a 50% decline in eGFR or ESKD over 5 years of follow-up (hazard ratio 2.2; 95% confidence interval, 1.2 to 3.8) in a Cox proportional hazard model adjusted for age, sex, and baseline eGFR. The addition of CHIP to 2-year and 5-year calibrated KFRE risk models improved ESKD predictions. Those with CHIP also had lower hemoglobin, higher ferritin, and higher red blood cell mean corpuscular volume versus those without CHIP.

CONCLUSIONS

In this exploratory analysis of individuals with preexisting CKD, CHIP was associated with higher baseline KFRE scores, greater progression of CKD, and anemia. Further research is needed to define the nature of the relationship between CHIP and kidney disease progression.

A Phenogenetic Axis that Modulates Clinical Manifestation and Predicts Treatment Outcome in Primary Myeloid Neoplasms

Although the concept of "myeloid neoplasm continuum" has long been proposed, few comparative genomics studies directly tested this hypothesis. Here we report a multi-modal data analysis of 730 consecutive newly diagnosed patients with primary myeloid neoplasm, along with 462 lymphoid neoplasm cases serving as the outgroup. Our study identified a "Pan-Myeloid Axis" along which patients, genes, and phenotypic features were all aligned in sequential order. Utilizing relational information of gene mutations along the Pan-Myeloid Axis improved prognostic accuracy for complete remission and overall survival in adult patients of de novo acute myeloid leukemia and for complete remission in adult patients of myelodysplastic syndromes with excess blasts. We submit that better understanding of the myeloid neoplasm continuum might shed light on how treatment should be tailored to individual diseases.

Significance

The current criteria for disease diagnosis treat myeloid neoplasms as a group of distinct, separate diseases. This work provides genomics evidence for a "myeloid neoplasm continuum" and suggests that boundaries between myeloid neoplastic diseases are much more blurred than previously thought.

Dysfunctional bone marrow endothelial progenitor cells are involved in patients with myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal disorders characterized by ineffective haematopoiesis and immune deregulation. Emerging evidence has shown the effect of bone marrow (BM) endothelial progenitor cells (EPCs) in regulating haematopoiesis and immune balance. However, the number and functions of BM EPCs in patients with different stages of MDS remain largely unknown.

METHODS

Patients with MDS (N = 30), de novo acute myeloid leukaemia (AML) (N = 15), and healthy donors (HDs) (N = 15) were enrolled. MDS patients were divided into lower-risk MDS (N = 15) and higher-risk MDS (N = 15) groups according to the dichotomization of the Revised International Prognostic Scoring System. Flow cytometry was performed to analyse the number of BM EPCs. Tube formation and migration assays were performed to evaluate the functions of BM EPCs. In order to assess the gene expression profiles of BM EPCs, RNA sequencing (RNA-seq) were performed. BM EPC supporting abilities of haematopoietic stem cells (HSCs), leukaemia cells and T cells were assessed by in vitro coculture experiments.

RESULTS

Increased but dysfunctional BM EPCs were found in MDS patients compared with HDs, especially in patients with higher-risk MDS. RNA-seq indicated the progressive change and differences of haematopoiesis- and immune-related pathways and genes in MDS BM EPCs. In vitro coculture experiments verified that BM EPCs from HDs, lower-risk MDS, and higher-risk MDS to AML exhibited a progressively decreased ability to support HSCs, manifested as elevated apoptosis rates and intracellular reactive oxygen species (ROS) levels and decreased colony-forming unit plating efficiencies of HSCs. Moreover, BM EPCs from higher-risk MDS patients demonstrated an increased ability to support leukaemia cells, characterized by increased proliferation, leukaemia colony-forming unit plating efficiencies, decreased apoptosis rates and apoptosis-related genes. Furthermore, BM EPCs induced T cell differentiation towards more immune-tolerant cells in higher-risk MDS patients in vitro. In addition, the levels of intracellular ROS and the apoptosis ratios were increased in BM EPCs from MDS patients, especially in higher-risk MDS patients, which may be therapeutic candidates for MDS patients.

CONCLUSION

Our results suggest that dysfunctional BM EPCs are involved in MDS patients, which indicates that improving haematopoiesis supporting ability and immuneregulation ability of BM EPCs may represent a promising therapeutic approach for MDS patients.

Venetoclax combination therapy in acute myeloid leukemia and myelodysplastic syndromes

PURPOSE OF REVIEW

Venetoclax is a BCL-2 inhibitor that was approved in combination therapy with hypomethylating agents or low dose cytarabine for newly diagnosed acute myeloid leukemia (AML). The purpose of this review is to outline the most recent venetoclax-based combination therapies in newly diagnosed or relapsed myelodysplastic syndrome (MDS) and AML patients.

RECENT FINDING

Venetoclax has been incorporated in various therapeutic regimens - either with chemotherapy, immunotherapy or targeted therapies. These combinations achieve high remission rates with deep molecular responses, as suggested by measurable residual disease measurements. There are concerns regarding the incomplete count recovery, prolonged cytopenia and infection rates, especially when combined with chemotherapy. There is also limited data concerning durability of these remissions, and the effectiveness in high-risk population (i.e. p53-mutated AML patients).

SUMMARY

Venetoclax-based combination therapies encompass novel therapeutic possibilities in MDS and AML with encouraging initial results. However, the exact role of each combination therapy and the long-term effects on patients' outcome are yet to be defined.

[The prognostic significance of pretransplantation evaluation of IPSS-R and WPSS in patients with myelodysplastic syndrome undergoing allogeneic hematopoietic stem cell transplantation]

Objective: This study aimed to explore the prognostic value of the revised international prognostic scoring system (IPSS-R) and the WHO prognostic scoring system (WPSS) in patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: The clinical data of 184 patients with MDS who received allo-HSCT from July 2016 to June 2019 were retrospectively analyzed. IPSS-R and WPSS were performed at diagnosis and before transplantation. The prognostic values of IPSS-R and WPSS and potential risk factors were explored. Results: With a median follow-up of 21.9 (0.5-47.5) months, the two-year overall survival (OS) and progression-free survival (PFS) rates were (75.1±3.4)% and (71.6±3.6)% , respectively. The two-year cumulative relapse rate and nonrelapse mortality rate were (11.9±0.1)% and (16.5±0.1)% , respectively. There were no significant differences in OS and PFS between the IPSS-R ≤3.5 and >3.5 groups at diagnosis (P=0.409; P=0.724). No significant differences in OS and PFS between the WPSS ≤2 and >2 groups (P=0.426; P=0.726) were observed as well. When the patients were reevaluated before transplantation, the OS and PFS of the IPSS-R ≤3.5 group were significantly better than >3.5 group [OS: (88.6±4.1)% vs (65.8±5.3)% , P=0.003; PFS: (87.6±4.2)% vs (60.5±5.8)% , P=0.002]. However, there were no significant differences in OS and PFS among the WPSS ≤2 and >2 groups (P=0.584; P=0.565). In addition, the OS and PFS of the improved group based on IPSS-R were significantly better than those of the unimproved group before transplantation [OS: (83.8±4.6)% vs (69.3±5.8)% , P=0.027; PFS: (82.8±4.4)% vs. (64.0±7.2)% , P=0.006]. Multivariate analysis indicated that a pretransplant IPSS-R of >3.5 (P=0.021, HR=2.510, 95% CI 1.151-5.476) and TP53 mutation (P=0.047, HR=2.460, 95% CI 1.014-5.971) were independent risk factors for OS, whereas a pretransplant IPSS-R of >3.5 (P=0.017, HR=2.457, 95% CI 1.175-5.141) and pretransplant cytogenetic poor and very poor (P=0.008, HR=2.765, 95% CI 1.305-5.856) were independent risk factors for PFS. Conclusion: A pretransplantation evaluation of IPSS-R could help determine the prognosis of patients with MDS undergoing allo-HSCT. In addition, patients with improved IPSS-R scores before undergoing allo-HSCT had a better prognosis.

BCOR and BCORL1 Mutations Drive Epigenetic Reprogramming and Oncogenic Signaling by Unlinking PRC1.1 from Target Genes

Polycomb repressive epigenetic complexes are recurrently dysregulated in cancer. Unlike polycomb repressive complex 2 (PRC2), the role of PRC1 in oncogenesis and therapy resistance is not well-defined. Here, we demonstrate that highly recurrent mutations of the PRC1 subunits BCOR and BCORL1 in leukemia disrupt assembly of a noncanonical PRC1.1 complex, thereby selectively unlinking the RING-PCGF enzymatic core from the chromatin-targeting auxiliary subcomplex. As a result, BCOR-mutated PRC1.1 is localized to chromatin but lacks repressive activity, leading to epigenetic reprogramming and transcriptional activation at target loci. We define a set of functional targets that drive aberrant oncogenic signaling programs in PRC1.1-mutated cells and primary patient samples. Activation of these PRC1.1 targets in BCOR-mutated cells confers acquired resistance to treatment while sensitizing to targeted kinase inhibition. Our study thus reveals a novel epigenetic mechanism that explains PRC1.1 tumor-suppressive activity and identifies a therapeutic strategy in PRC1.1-mutated cancer.

SIGNIFICANCE

We demonstrate that BCOR and BCORL1 mutations in leukemia unlink PRC1.1 repressive function from target genes, resulting in epigenetic reprogramming and activation of aberrant cell signaling programs that mediate treatment resistance. Our study provides mechanistic insights into the pathogenesis of PRC1.1-mutated leukemia that inform novel therapeutic approaches. This article is highlighted in the In This Issue feature, p. 85.

The significance of CUX1 and chromosome 7 in myeloid malignancies

PURPOSE OF REVIEW

Loss of chromosome 7 has long been associated with adverse-risk myeloid malignancy. In the last decade, CUX1 has been identified as a critical tumor suppressor gene (TSG) located within a commonly deleted segment of chromosome arm 7q. Additional genes encoded on 7q have also been identified as bona fide myeloid tumor suppressors, further implicating chromosome 7 deletions in disease pathogenesis. This review will discuss the clinical implications of del(7q) and CUX1 mutations, both in disease and clonal hematopoiesis, and synthesize recent literature on CUX1 and other chromosome 7 TSGs.

RECENT FINDINGS

Two major studies, including a new mouse model, have been published that support a role for CUX1 inactivation in the development of myeloid neoplasms. Additional recent studies describe the cellular and hematopoietic effects from loss of the 7q genes LUC7L2 and KMT2C/MLL3, and the implications of chromosome 7 deletions in clonal hematopoiesis.

SUMMARY

Mounting evidence supports CUX1 as being a key chromosome 7 TSG. As 7q encodes additional myeloid regulators and tumor suppressors, improved models of chromosome loss are needed to interrogate combinatorial loss of these critical 7q genes.

NPM1 ablation induces HSC aging and inflammation to develop myelodysplastic syndrome exacerbated by p53 loss

Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis with morphologic dysplasia and a propensity to transform into overt acute myeloid leukemia (AML). Our analysis of two cohorts of 20 MDS and 49 AML with multi-lineage dysplasia patients shows a reduction in Nucleophosmin 1 (NPM1) expression in 70% and 90% of cases, respectively. A mouse model of Npm1 conditional knockout (cKO) in hematopoietic cells reveals that Npm1 loss causes premature aging of hematopoietic stem cells (HSCs). Mitochondrial activation in Npm1-deficient HSCs leads to aberrant activation of the NLRP3 inflammasome, which correlates with a developing MDS-like phenotype. Npm1 cKO mice exhibit shortened survival times, and expansion of both the intra- and extra-medullary myeloid populations, while evoking a p53-dependent response. After transfer into a p53 mutant background, the resulting Npm1/p53 double KO mice develop fatal leukemia within 6 months. Our findings identify NPM1 as a regulator of HSC aging and inflammation and highlight the role of p53 in MDS progression to leukemia.

High prevalence of myeloid malignancies in progeria with Werner syndrome is associated with p53 insufficiency

Werner syndrome (WS) is a progeroid syndrome caused by mutations in the WRN gene, which encodes the RecQ type DNA helicase for the unwinding of unusual DNA structures and is implicated in DNA replication, DNA repair, and telomere maintenance. WS patients are prone to develop malignant neoplasms, including hematological malignancies. However, the pathogenesis of WS-associated hematological malignancies remains uncharacterized. Here we investigated the somatic gene mutations in WS-associated MDS/AML. Whole-exome sequencing (WES) of 4 WS patients with MDS/AML revealed that all patients had somatic mutations in TP53 but no other recurrent mutations in MDS/AML. TP53 mutations were identified at low allele frequencies at more than one year before the MDS/AML stage. All 4 patients had complex chromosomal abnormalities including those that involved TP53. Targeted sequencing of 9 WS patients without apparent blood abnormalities did not detect recurrent mutations in MDS/AML except for a PPM1D mutation. These results suggest that WS patients are apt to acquire TP53 mutations and/or chromosomal abnormalities involving TP53, rather than other MDS/AML-related mutations. TP53 mutations are frequently associated with prior exposure to chemotherapy; however, all 4 WS patients with TP53 mutations/deletions had not received any prior chemotherapy, suggesting a pathogenic link between WRN mutations and p53 insufficiency. These results indicate that WS hematopoietic stem cells with WRN insufficiency acquire competitive fitness by inactivating p53, which may cause complex chromosomal abnormalities and the subsequent development of myeloid malignancies. These findings promote our understanding of the pathogenesis of myeloid malignancies associated with progeria.

The spectrum of genetic mutations in myelodysplastic syndrome: Should we update prognostication?

The natural history of patients with myelodysplastic syndrome (MDS) is dependent upon the presence and magnitude of diverse genetic and molecular aberrations. The International Prognostic Scoring System (IPSS) and revised IPSS (IPSS-R) are the most widely used classification and prognostic systems; however, somatic mutations are not currently incorporated into these systems, despite evidence of their independent impact on prognosis. Our manuscript reviews prognostic information for TP53, EZH2, DNMT3A, ASXL1, RUNX1, SRSF2, CBL, IDH 1/2, TET2, BCOR, ETV6, GATA2, U2AF1, ZRSR2, RAS, STAG2, and SF3B1. Mutations in TP53, EZH2, ASXL1, DNMT3A, RUNX1, SRSF2, and CBL have extensive evidence for their negative impact on survival, whereas SF3B1 is the lone mutation carrying a favorable prognosis. We use the existing literature to propose the incorporation of somatic mutations into the IPSS-R. More data are needed to define the broad spectrum of other genetic lesions, as well as the impact of variant allele frequencies, class of mutation, and impact of multiple interactive genomic lesions. We postulate that the incorporation of these data into MDS prognostication systems will not only enhance our therapeutic decision making but lead to targeted treatment in an attempt to improve outcomes in this formidable 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.

TP53 mutation defines a unique subgroup within complex karyotype de novo and therapy-related MDS/AML

Among patients with MDS and AML, the presence of TP53 mutation in the context of CK identifies a homogeneously aggressive disease.

TP53 mutation (in particular multihit) identifies an aggressive disease, irrespective of the blast count or therapy-relatedness.

A subset of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) show complex karyotype (CK), and these cases include a relatively high proportion of cases of therapy-related myeloid neoplasms and TP53 mutations. We aimed to evaluate the clinicopathologic features of outcome of 299 AML and MDS patients with CK collected from multiple academic institutions. Mutations were present in 287 patients (96%), and the most common mutation detected was in TP53 gene (247, 83%). A higher frequency of TP53 mutations was present in therapy-related cases (P = .008), with a trend for worse overall survival (OS) in therapy-related patients as compared with de novo disease (P = .08) and within the therapy-related group; the presence of TP53 mutation strongly predicted for worse outcome (P = .0017). However, there was no difference in survival between CK patients based on categorization of AML vs MDS (P = .96) or presence of absence of circulating blasts ≥1% (P = .52). TP53-mutated patients presented with older age (P = .06) and lower hemoglobin levels (P = .004) and marrow blast counts (P = .02) compared with those with CK lacking TP53 mutation. Multivariable analysis identified presence of multihit TP53 mutation as strongest predictor of worse outcome, whereas neither a diagnosis of AML vs MDS nor therapy-relatedness independently influenced OS. Our findings suggest that among patients with MDS and AML, the presence of TP53 mutation (in particular multihit TP53 mutation) in the context of CK identifies a homogeneously aggressive disease, irrespective of the blast count at presentation or therapy-relatedness. The current classification of these cases into different disease categories artificially separates a single biologic disease entity.

Analysis of genetic variants in myeloproliferative neoplasms using a 22-gene next-generation sequencing panel

Background

The Philadelphia (Ph)-negative myeloproliferative neoplasms (MPNs), namely essential thrombocythaemia (ET), polycythaemia vera (PV) and primary myelofibrosis (PMF), are a group of chronic clonal haematopoietic disorders that have the propensity to advance into bone marrow failure or acute myeloid leukaemia; often resulting in fatality. Although driver mutations have been identified in these MPNs, subtype-specific markers of the disease have yet to be discovered. Next-generation sequencing (NGS) technology can potentially improve the clinical management of MPNs by allowing for the simultaneous screening of many disease-associated genes.

Methods

The performance of a custom, in-house designed 22-gene NGS panel was technically validated using reference standards across two independent replicate runs. The panel was subsequently used to screen a total of 10 clinical MPN samples (ET n = 3, PV n = 3, PMF n = 4). The resulting NGS data was then analysed via a bioinformatics pipeline.

Results

The custom NGS panel had a detection limit of 1% variant allele frequency (VAF). A total of 20 unique variants with VAFs above 5% (4 of which were putatively novel variants with potential biological significance) and one pathogenic variant with a VAF of between 1 and 5% were identified across all of the clinical MPN samples. All single nucleotide variants with VAFs ≥ 15% were confirmed via Sanger sequencing.

Conclusions

The high fidelity of the NGS analysis and the identification of known and novel variants in this study cohort support its potential clinical utility in the management of MPNs. However, further optimisation is needed to avoid false negatives in regions with low sequencing coverage, especially for the detection of driver mutations in MPL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01145-0.

Lessons From Pediatric MDS: Approaches to Germline Predisposition to Hematologic Malignancies

Pediatric myelodysplastic syndromes (MDS) often raise concern for an underlying germline predisposition to hematologic malignancies, referred to as germline predisposition herein. With the availability of genetic testing, it is now clear that syndromic features may be lacking in patients with germline predisposition. Many genetic lesions underlying germline predisposition may also be mutated somatically in de novo MDS and leukemias, making it critical to distinguish their germline origin. The verification of a suspected germline predisposition informs therapeutic considerations, guides monitoring pre- and post-treatment, and allows for family counseling. Presentation of MDS due to germline predisposition is not limited to children and spans a wide age range. In fact, the risk of MDS may increase with age in many germline predisposition conditions and can present in adults who lack classical stigmata in their childhood. Furthermore, germline predisposition associated with DDX41 mutations presents with older adult-onset MDS. Although a higher proportion of pediatric patients with MDS will have a germline predisposition, the greater number of MDS diagnoses in adult patients may result in a larger overall number of those with an underlying germline predisposition. In this review, we present a framework for the evaluation of germline predisposition to MDS across all ages. We discuss characteristics of personal and family history, clinical exam and laboratory findings, and integration of genetic sequencing results to assist in the diagnostic evaluation. We address the implications of a diagnosis of germline predisposition for the individual, for their care after MDS therapy, and for family members. Studies on MDS with germline predisposition have provided unique insights into the pathogenesis of hematologic malignancies and mechanisms of somatic genetic rescue vs. disease progression. Increasing recognition in adult patients will inform medical management and may provide potential opportunities for the prevention or interception of malignancy.

Mutant PPM1D- and TP53-Driven Hematopoiesis Populates the Hematopoietic Compartment in Response to Peptide Receptor Radionuclide Therapy

PURPOSE

Hematologic toxic effects of peptide receptor radionuclide therapy (PRRT) can be permanent. Patients with underlying clonal hematopoiesis (CH) may be more inclined to develop hematologic toxicity after PRRT. However, this association remains understudied.

MATERIALS AND METHODS

We evaluated pre- and post-PRRT blood samples of patients with neuroendocrine tumors. After initial screening, 13 cases of interest were selected. Serial blood samples were obtained on 4 of 13 patients. Genomic DNA was analyzed using a 100-gene panel. A variant allele frequency cutoff of 1% was used to call CH.

RESULT

Sixty-two percent of patients had CH at baseline. Persistent cytopenias were noted in 64% (7 of 11) of the patients. Serial sample analysis demonstrated that PRRT exposure resulted in clonal expansion of mutant DNA damage response genes (TP53, CHEK2, and PPM1D) and accompanying cytopenias in 75% (3 of 4) of the patients. One patient who had a normal baseline hemogram and developed persistent cytopenias after PRRT exposure showed expansion of mutant PPM1D (variant allele frequency increased to 20% after exposure from < 1% at baseline). In the other two patients, expansion of mutant TP53, CHEK2, and PPM1D clones was also noted along with cytopenia development.

CONCLUSION

The shifts in hematopoietic clonal dynamics in our study were accompanied by emergence and persistence of cytopenias. These cytopenias likely represent premalignant state, as PPM1D-, CHEK2-, and TP53-mutant clones by themselves carry a high risk for transformation to therapy-related myeloid neoplasms. Future studies should consider CH screening and longitudinal monitoring as a key risk mitigation strategy for patients with neuroendocrine tumors receiving PRRT.

Adding venetoclax to fludarabine/busulfan RIC transplant for high-risk MDS and AML is feasible, safe, and active

Adding the selective BCL-2 inhibitor venetoclax to reduced-intensity conditioning chemotherapy (fludarabine and busulfan [FluBu2]) may enhance antileukemic cytotoxicity and thereby reduce the risk of posttransplant relapse. This phase 1 study investigated the recommended phase 2 dose (RP2D) of venetoclax, a BCL-2 selective inhibitor, when added to FluBu2 in adult patients with high-risk acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and MDS/myeloproliferative neoplasms (MPN) undergoing transplant. Patients received dose-escalated venetoclax (200-400 mg daily starting day -8 for 6-7 doses) in combination with fludarabine 30 mg/m2 per day for 4 doses and busulfan 0.8 mg/kg twice daily for 8 doses on day -5 to day -2 (FluBu2). Transplant related-toxicity was evaluated from the first venetoclax dose on day -8 to day 28. Twenty-two patients were treated. At study entry, 5 patients with MDS and MDS/MPN had 5% to 10% marrow blasts, and 18 (82%) of 22 had a persistent detectable mutation. Grade 3 adverse events included mucositis, diarrhea, and liver transaminitis (n = 3 each). Neutrophil/platelet recovery and acute/chronic graft-versus-host-disease rates were similar to those of standard FluBu2. No dose-limiting toxicities were observed. The RP2D of venetoclax was 400 mg daily for 7 doses. With a median follow-up of 14.7 months (range, 8.6-24.8 months), median overall survival was not reached, and progression-free survival was 12.2 months (95% confidence interval, 6.0-not estimable). In patients with high-risk AML, MDS, and MDS/MPN, adding venetoclax to FluBu2 was feasible and safe. To further address relapse risk, assessment of maintenance therapy after venetoclax plus FluBu2 transplant is ongoing. This study was registered at clinicaltrials.gov as #NCT03613532.

Prognostic scoring systems and risk stratification in myelodysplastic syndrome: focus on integration of molecular profile

Myelodysplastic syndromes (MDS) form a clinically and molecularly heterogeneous disease group. Precise risk stratification remains crucial for choosing optimal management strategies. Several conventional prognostic scoring systems have been developed and validated in the MDS population. These risk models divide patients into prognostic subgroups based on clinical and cytogenetic characteristics. Lack of dynamicity, variable risk estimate across models, and heterogeneity within intermediate-risk group are the limitations of traditional models like IPSS-R, with questionable relevance of these scoring systems in treated MDS patients. Recent progress in next-generation sequencing techniques has improved understanding of the distribution and prognostic importance of recurrent genetic mutations in MDS. Early studies have suggested that incorporating mutations in risk stratification could supplement IPSS-R in further refining the model's performance in predicting overall survival and risk of transformation to acute myeloid leukemia and should translate into a molecularly driven prognostication approach in the near future.

Establishment of a Predictive Model for GvHD-free, Relapse-free Survival after Allogeneic HSCT using Ensemble Learning

Stacked ensemble of machine-learning algorithms could establish more accurate prediction model for survival analysis than existing methods.

Stacked ensemble model can be applied to personalized prediction of HSCT outcomes from pretransplant characteristics.

Graft-versus-host disease-free, relapse-free survival (GRFS) is a useful composite end point that measures survival without relapse or significant morbidity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aimed to develop a novel analytical method that appropriately handles right-censored data and competing risks to understand the risk for GRFS and each component of GRFS. This study was a retrospective data-mining study on a cohort of 2207 adult patients who underwent their first allo-HSCT within the Kyoto Stem Cell Transplantation Group, a multi-institutional joint research group of 17 transplantation centers in Japan. The primary end point was GRFS. A stacked ensemble of Cox Proportional Hazard (Cox-PH) regression and 7 machine-learning algorithms was applied to develop a prediction model. The median age for the patients was 48 years. For GRFS, the stacked ensemble model achieved better predictive accuracy evaluated by C-index than other state-of-the-art competing risk models (ensemble model: 0.670; Cox-PH: 0.668; Random Survival Forest: 0.660; Dynamic DeepHit: 0.646). The probability of GRFS after 2 years was 30.54% for the high-risk group and 40.69% for the low-risk group (hazard ratio compared with the low-risk group: 2.127; 95% CI, 1.19-3.80). We developed a novel predictive model for survival analysis that showed superior risk stratification to existing methods using a stacked ensemble of multiple machine-learning algorithms.

PARP Inhibitors and Myeloid Neoplasms: A Double-Edged Sword

Simple Summary

Poly(ADP-ribose) polymerase (PARP) inhibitors, which are medications approved to treat various solid tumors, including breast, prostate, ovarian, and prostate cancers, are being examined in hematological malignancies. This review summarizes the potential role of PARP inhibitors in the treatment of myeloid diseases, particularly acute myeloid leukemia (AML). We review ongoing clinical studies investigating the safety and efficacy of PARP inhibitors in the treatment of AML, focusing on specific molecular and genetic AML subgroups that could be particularly sensitive to PARP inhibitor treatment. We also discuss reports describing an increased risk of treatment-related myeloid neoplasms in patients receiving PARP inhibitors for solid tumors.

Abstract

Despite recent discoveries and therapeutic advances in aggressive myeloid neoplasms, there remains a pressing need for improved therapies. For instance, in acute myeloid leukemia (AML), while most patients achieve a complete remission with conventional chemotherapy or the combination of a hypomethylating agent and venetoclax, de novo or acquired drug resistance often presents an insurmountable challenge, especially in older patients. Poly(ADP-ribose) polymerase (PARP) enzymes, PARP1 and PARP2, are involved in detecting DNA damage and repairing it through multiple pathways, including base excision repair, single-strand break repair, and double-strand break repair. In the context of AML, PARP inhibitors (PARPi) could potentially exploit the frequently dysfunctional DNA repair pathways that, similar to deficiencies in homologous recombination in BRCA-mutant disease, set the stage for cell killing. PARPi appear to be especially effective in AML with certain gene rearrangements and molecular characteristics (RUNX1-RUNX1T1 and PML-RARA fusions, FLT3- and IDH1-mutated). In addition, PARPi can enhance the efficacy of other agents, particularly alkylating agents, TOP1 poisons, and hypomethylating agents, that induce lesions ordinarily repaired via PARP1-dependent mechanisms. Conversely, emerging reports suggest that long-term treatment with PARPi for solid tumors is associated with an increased incidence of myelodysplastic syndrome (MDS) and AML. Here, we (i) review the pre-clinical and clinical data on the role of PARPi, specifically olaparib, talazoparib, and veliparib, in aggressive myeloid neoplasms and (ii) discuss the reported risk of MDS/AML with PARPi, especially as the indications for PARPi use expand to include patients with potentially curable cancer.

The Dawn of next generation DNA sequencing in myelodysplastic syndromes- experience from Pakistan

Background

Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic stem cells exhibiting ineffective hematopoiesis and tendency for transformation into acute myeloid leukemia (AML). The available karyotyping and fluorescent in situ hybridization provide limited information on molecular abnormalities for diagnosis/prognosis of MDS. Next generation DNA sequencing (NGS), providing deep insights into molecular mechanisms being involved in pathophysiology, was employed to study MDS in Pakistani cohort.

Patients and methods

It was a descriptive cross-sectional study carried out at National institute of blood diseases and bone marrow transplant from 2016 to 2019. Total of 22 cases of MDS were included. Complete blood counts, bone marrow assessment and cytogenetic analysis was done. Patients were classified according to revised WHO classification 2016 and IPSS score was applied for risk stratification. Baseline blood samples were subjected to analysis by NGS using a panel of 54 genes associated with myeloid malignancies.

Results

The median age of patients was 48.5 ± 9.19 years. The most common presenting complaint was weakness 10(45.45%). Cytogenetics analysis revealed abnormal karyotype in 10 (45.45%) patients. On NGS, 54 non-silent rare frequency somatic mutational events in 29 genes were observed (average of 3.82 (SD ± 2.08) mutations per patient), including mutations previously not observed in MDS or AML. Notably, two genes of cohesin complex, RAD21 and STAG2, and two tumor suppressor genes, CDKN2A and TP53, contained highest number of recurrent non-silent somatic mutations in the MDS. Strikingly, a missense somatic mutation p.M272Rof Rad21 was observed in 13 cases. Overall, non-silent somatic mutations in these four genes were observed in 21 of the 22 cases. The filtration with PharmGKB database highlighted a non-synonymous genetic variant rs1042522 [G > C] located in the TP53. Genotype GG and GC of this variant are associated with decreased response to cisplatin and paclitaxel chemotherapy. These two genotypes were found in 13 cases.

Conclusion

Sequencing studies suggest that numerous genetic variants are involved in the initiation of MDS and in the development of AML. In countries like Pakistan where financial reservation of patients makes the use of such analysis even more difficult when the availability of advanced techniques is already a prevailing issue, our study could be an initiating effort in adding important information to the local data. Further studies and large sample size are needed in future to enlighten molecular profiling and ultimately would be helpful to compare and contrast the molecular characteristics of Asian versus global population.