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

Management of adult patients with CMML undergoing allo-HCT: recommendations from the EBMT PH&G Committee

ABSTRACT

Chronic myelomonocytic leukemia (CMML) is a heterogeneous disease presenting with either myeloproliferative or myelodysplastic features. Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only potentially curative option, but the inherent toxicity of this procedure makes the decision to proceed to allo-HCT challenging, particularly because patients with CMML are mostly older and comorbid. Therefore, the decision between a nonintensive treatment approach and allo-HCT represents a delicate balance, especially because prospective randomized studies are lacking and retrospective data in the literature are conflicting. International consensus on the selection of patients and the ideal timing of allo-HCT, specifically in CMML, could not be reached in international recommendations published 6 years ago. Since then, new, CMML-specific data have been published. The European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines (PH&G) Committee assembled a panel of experts in the field to provide the first best practice recommendations on the role of allo-HCT specifically in CMML. Recommendations were based on the results of an international survey, a comprehensive review of the literature, and expert opinions on the subject, after structured discussion and circulation of recommendations. Algorithms for patient selection, timing of allo-HCT during the course of the disease, pretransplant strategies, allo-HCT modality, as well as posttransplant management for patients with CMML were outlined. The keynote message is, that once a patient has been identified as a transplant candidate, upfront transplantation without prior disease-modifying treatment is preferred to maximize chances of reaching allo-HCT whenever possible, irrespective of bone marrow blast counts.

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.

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

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

Evaluating targeted therapies in older patients with TP53-mutated AML

Mutation of thetumor suppressor gene, TP53 (tumor protein 53), occurs in up to 15% of all patients with acute myeloid leukemia (AML) and is enriched within specific clinical subsets, most notably in older adults, and including secondary AML cases arising from preceding myeloproliferative neoplasm (MPN), myelodysplastic syndrome (MDS), patients exposed to prior DNA-damaging, cytotoxic therapies. In all cases, these tumors have remained difficult to effectively treat with conventional therapeutic regimens. Newer approaches fortreatmentofTP53-mutated AML have shifted to interventions that maymodulateTP53 function, target downstream molecular vulnerabilities, target non-p53 dependent molecular pathways, and/or elicit immunogenic responses. This review will describe the basic biology of TP53, the clinical and biological patterns of TP53 within myeloid neoplasms with a focus on elderly AML patients and will summarize newer therapeutic strategies and current clinical trials.

Latest Insights and Therapeutic Advances in Myelodysplastic Neoplasms

Myelodysplastic syndromes/neoplasms (MDSs) encompass a range of hematopoietic malignancies, commonly affecting elderly individuals. Molecular alterations in the hematopoietic stem cell compartment drive disease pathogenesis. Recent advancements in genomic profiling have provided valuable insights into the biological underpinnings of MDSs and have expanded therapeutic options, particularly for specific molecularly defined subgroups. This review highlights the diagnostic principles, classification updates, prognostic stratification systems, and novel treatments, which could inform future clinical trials and enhance the management of adult MDS patients, particularly for specific molecularly defined subgroups.

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.

Myelodysplastic Neoplasms (MDS): The Current and Future Treatment Landscape

Myelodysplastic neoplasms (MDS) are a heterogenous clonal disorder of hemopoietic stem cells characterized by cytomorphologic dysplasia, ineffective hematopoiesis, peripheral cytopenias and risk of progression to acute myeloid leukemia (AML). Our understanding of this disease has continued to evolve over the last century. More recently, prognostication and treatment have been determined by cytogenetic and molecular data. Specific genetic abnormalities, such as deletion of the long arm of chromosome 5 (del(5q)), TP53 inactivation and SF3B1 mutation, are increasingly associated with disease phenotype and outcome, as reflected in the recently updated fifth edition of the World Health Organization Classification of Hematolymphoid Tumors (WHO5) and the International Consensus Classification 2022 (ICC 2022) classification systems. Treatment of lower-risk MDS is primarily symptom directed to ameliorate cytopenias. Higher-risk disease warrants disease-directed therapy at diagnosis; however, the only possible cure is an allogenic bone marrow transplant. Novel treatments aimed at rational molecular and cellular pathway targets have yielded a number of candidate drugs over recent years; however few new approvals have been granted. With ongoing research, we hope to increasingly offer our MDS patients tailored therapeutic approaches, ultimately decreasing morbidity and mortality.

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.

Prophylactic donor lymphocyte infusion after haploidentical hematopoietic cell transplantation and post-transplant cyclophosphamide for treatment of high-risk myeloid neoplasms in children: A retrospective study

BACKGROUND

Post-transplant cyclophosphamide (PTCy) has been recommended for prevention of graft-versus-host disease (GvHD) following haploidentical hematopoietic cell transplantation (haplo-HCT) for treatment of malignant blood diseases, but disease relapse remains a problem. Although donor lymphocyte infusion (DLI) is reported to be effective for treating post-transplantation relapse, the efficacy and safety of prophylactic-DLI (pro-DLI) post haplo-HCT, and PTCy in pediatric patients with hematological malignancies is unknown.

METHODS

We retrospectively analyzed the outcomes of 54 pediatric patients with high-risk myeloid neoplasms who received a PTCy regimen for GvHD prophylaxis and pro-DLI after haploidentical peripheral blood stem cell transplantation. The high-risk myeloid neoplasms in this cohort included acute myeloid leukemia (n = 46) and myelodysplastic syndromes (n = 8).

RESULTS

Median follow-up was for 19.7 (range: 3.4-46.6) months. The cumulative incidences of grade II-IV and III-IV acute GvHD were 37.0% (95% CI: 22.7%-48.7%) and 16.7% (95% CI: 6.1%-26.0%), respectively. There were no graft-failure events, and the 2-year rate of moderate/severe chronic GvHD was 8.1% (95% CI: 0%-16.7%). The 2-year non-relapse mortality, relapse, disease-free survival, GvHD-free relapse-free survival, and overall survival rates were 5.1% (95% CI: 0%-11.7%), 16.6% (95% CI: 5.3%-26.6%), 78.9% (95% CI: 68.0%-91.6%), 62.2% (95% CI: 49.4%-78.3%), and 87.3% (95% CI: 78.3%-97.4%), respectively.

CONCLUSIONS

Prophylactic donor lymphocyte infusion in the setting of haploidentical hematopoietic cell transplantation with post-transplant cyclophosphamide appears to be effective and safe in pediatric patients with high-risk myeloid neoplasms.

How do we improve the translation of new evidence into the practice of hematopoietic cell transplantation and cellular therapy?

The field of hematopoietic cell transplantation and cell therapy (HCT/CT) is advancing rapidly to bring an ever-expanding collection of potentially curative therapies to patients with malignant and non-malignant diseases. The impact of these therapies depends on our ability to implement them as new evidence becomes available to advance the quality of care. There is often a long delay between evidence development and adoption of therapies based on that evidence into clinical practice. In this review, we describe the potential factors based on an implementation framework that could act as facilitators or barriers to adoption of therapies in the context of HCT/CT. We highlight two examples, the first to showcase the efforts to improve the efficiency of adoption of new findings and accelerate improvement in care of HCT/CT patients and the second to discuss the challenges in real world implementation of chimeric antigen receptor T cell therapy. We conclude by reviewing strategies to improve translation of evidence and ways to measure their success.

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.