Maintenance therapy for AML after allogeneic HCT

Clinical Outcomes of Early WT1 mRNA Reduction After Remission Induction in Newly Diagnosed Acute Myeloid Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Wilms' Tumor 1 (WT1) mRNA is a non-specific marker of measurable residual disease in acute myeloid leukemia (AML). Few studies have focused on the prognostic value of WT1 mRNA after initial remission induction of patients with AML who have received transplant treatments. Thus, we retrospectively analyzed the clinical features and prognostic impact of WT1 mRNA reduction in patients with AML after initial remission induction at our hospital. We classified the reduction in WT1 mRNA levels using logarithmic stratification, with particular focus on the prognostic impact of a 3-log reduction after initial remission induction. This single-center, retrospective, observational study included 71 consecutive patients with AML who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) between April 2013 and June 2023 and had WT1 mRNA quantified. Patients were grouped based on whether a 3-log reduction was observed during follow-up (N=30) or not (N=41). Among patients who did not achieve a 3-log reduction, European Leukemia Net (ELN) 2022 adverse risk was more common, and fewer patients showed complete hematological responses at transplantation. Patients who reached a 3-log reduction in WT1 mRNA after the initial remission induction had significantly longer overall survival (OS) and progression-free survival (PFS) and a lower relapse rate than patients who had not reached a 3-log reduction (2-year OS: 79.7% vs. 27.5%, 2-year PFS: 83.1% vs. 11.7% and 2-year cumulative relapse rate: 5.9% vs. 81.2%). In multivariate analysis, a 3-log reduction in WT1 mRNA after initial remission induction and ELN 2022 adverse risk by genetics were significantly associated with OS and PFS. We identified that patients with AML undergoing HSCT with an early and deep 3-log reduction in WT1 mRNA after initial remission induction were associated with low relapse rates and better long-term prognosis. Our data highlight the importance of WT1 mRNA reduction after initial remission induction.

Pre-transplantation levels of lysine (K)-specific methyltransferase 2A (KMT2A) partial tandem duplications can predict relapse of acute myeloid leukemia patients following haploidentical donor hematopoietic stem cell transplantation

We aimed to identify dynamic changes of lysine (K)-specific methyltransferase 2A partial tandem duplications (KMT2A-PTD) before and after haploidentical donor hematopoietic stem cell transplantation (HID HSCT) and explore the prognostic value of pre-transplantation levels of KMT2A-PTD in acute myeloid leukemia (AML) receiving HID HSCT. Consecutive 64 AML patients with KMT2A-PTD positivity at diagnosis receiving HID HSCT were included in this study. Patients with KMT2A-PTD ≥1% before HSCT had a slower decrease of KMT2A-PTD after HID HSCT. Patients with KMT2A-PTD ≥1% before HID HSCT had a higher cumulative incidence of relapse (36.4%, 95% confidence interval [CI]: 6.3%-66.5%) at 2 years after HSCT than those with KMT2A-PTD <1% (7.5%, 95% CI: 0.3%-14.7%, P = .010). In multivariable analysis, KMT2A-PTD ≥1% before HID HSCT was the only independent risk factor for relapse (hazard ratio [HR]: 4.90; 95% CI: 1.22-19.59; P = .025). Thus, pre-transplantation levels of KMT2A-PTD could predict relapse in AML patients following HID HSCT.

Post-Transplant Maintenance Therapy in Acute Myeloid Leukemia

Allogeneic hematopoietic cell transplantation (allo-HCT) is potentially curative for patients with acute myeloid leukemia (AML). However, the post-transplant relapse rate ranges from 40 to 70%, particularly with reduced intensity conditioning, and remains a major cause of treatment failure for these patients due to the limited efficacy of salvage therapy options. Strategies to mitigate this risk are urgently needed. In the past few years, the basic framework of post-transplant maintenance has been shaped by several clinical trials investigating targeted therapy, chemotherapy, and immunomodulatory therapies. Although the practice of post-transplant maintenance in AML has become more common, there remain challenges regarding the feasibility and efficacy of this strategy. Here, we review major developments in post-transplant maintenance in AML, along with ongoing and future planned studies in this area, outlining the limitations of available data and our future goals.

Azacitidine maintenance therapy for blastic plasmacytoid dendritic cell neoplasm allograft: A case report

BACKGROUND

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, highly invasive malignant neoplasm. There is no universally accepted standard of care because of its rarity and the dearth of prospective research. It is still challenging for some patients to achieve persistent clinical remission or cure, despite the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT), indicating that there is still a significant recurrence rate. We report a case of prevention of BPDCN allograft recurrence by azacitidine maintenance therapy and review the relevant literature.

CASE SUMMARY

We report a 41-year-old man with BPDCN who was admitted to hospital due to skin sclerosis for > 5 mo' duration. BPDCN was diagnosed by combined clinical assessment and laboratory examinations. Following diagnosis, the patients underwent induction consolidation chemotherapy to achieve the first complete remission, followed by bridging allo-HSCT. Post-transplantation, azacitidine (75 mg/m2 for 7 d) was administered as maintenance therapy, with repeat administration every 4-6 wk and appropriate extension of the chemotherapy cycle. After 10 cycles, the patient has been disease free for 26 mo after transplantation. Regular assessments of bone marrow morphology, minimal residual disease, full donor chimerism, Epstein-Barr virus, and cytomegalovirus all yielded normal results with no abnormalities detected.

CONCLUSION

Azacitidine may be a safe and effective maintenance treatment for BPDCN following transplantation because there were no overt adverse events during the course of treatment.

Granulocyte-Macrophage-Colony-Stimulating-Factor Combined with Prostaglandin E1 Create Dendritic Cells of Leukemic Origin from AML Patients' Whole Blood and Whole Bone Marrow That Mediate Antileukemic Processes after Mixed Lymphocyte Culture

Although several (chemotherapeutic) protocols to treat acute myeloid leukemia (AML) are available, high rates of relapses in successfully treated patients occur. Strategies to stabilize remissions are greatly needed. The combination of the (clinically approved) immune-modulatory compounds Granulocyte-Macrophage-Colony-Stimulating-Factor (GM-CSF) and Prostaglandine E1 (PGE-1) (Kit-M) converts myeloid blasts into dendritic cells of leukemic origin (DCleu). After stimulation with DCleu ex vivo, leukemia-specific antileukemic immune cells are activated. Therefore, Kit-M treatment may be an attractive immunotherapeutic tool to treat patients with myeloid leukemia. Kit-M-mediated antileukemic effects on whole bone marrow (WBM) were evaluated and compared to whole blood (WB) to evaluate the potential effects of Kit-M on both compartments. WB and WBM samples from 17 AML patients at first diagnosis, in persisting disease and at relapse after allogeneic stem cell transplantation (SCT) were treated in parallel with Kit-M to generate DC/DCleu. Untreated samples served as controls. After a mixed lymphocyte culture enriched with patients' T cells (MLC), the leukemia-specific antileukemic effects were assessed through the degranulation- (CD107a+ T cells), the intracellular IFNγ production- and the cytotoxicity fluorolysis assay. Quantification of cell subtypes was performed via flow cytometry. In both WB and WBM significantly higher frequencies of (mature) DCleu were generated without induction of blast proliferation in Kit-M-treated samples compared to control. After MLC with Kit-M-treated vs. not pretreated WB or WBM, frequencies of (leukemia-specific) immunoreactive cells (e.g., non-naive, effector-, memory-, CD3+β7+ T cells, NK- cells) were (significantly) increased, whereas leukemia-specific regulatory T cells (Treg, CD152+ T cells) were (significantly) decreased. The cytotoxicity fluorolysis assay showed a significantly improved blast lysis in Kit-M-treated WB and WBM compared to control. A parallel comparison of WB and WBM samples revealed no significant differences in frequencies of DCleu, (leukemia-specific) immunoreactive cells and achieved antileukemic processes. Kit-M was shown to have comparable effects on WB and WBM samples regarding the generation of DCleu and activation of (antileukemic) immune cells after MLC. This was true for samples before or after SCT. In summary, a potential Kit-M in vivo treatment could lead to antileukemic effects in WB as well as WBM in vivo and to stabilization of the disease or remission in patients before or after SCT. A clinical trial is currently being planned.

Immunopathogenic mechanisms and modulatory approaches to graft-versus-host disease prevention in acute myeloid leukaemia

Allogeneic haematopoietic stem cell transplantation (HSCT) remains the only potential cure for intermediate to high-risk acute myeloid leukaemia (AML). The therapeutic effect of HSCT is largely dependent on the powerful donor-derived immune response against recipient leukaemia cells, known as graft-versus-leukaemia effect (GvL). However, the donor-derived immune system can also cause acute or chronic damage to normal recipient organs and tissues, in a process known as graft-versus-host disease (GvHD). GvHD is a leading cause of non-relapse mortality in HSCT recipients. There are many similarities and cross talk between the immune pathways of GvL and GvHD. Studies have demonstrated that both processes require the presence of mismatched alloantigens between the donor and recipient, and activation of immune responses centered around donor T-cells, which can be further modulated by various recipient or donor factors. Dissecting GvL from GvHD to achieve more effective GvHD prevention and enhanced GvL has been the holy grail of HSCT research. In this review, we focused on the key factors that contribute to the immune responses of GvL and GvHD, the effect on GvL with different GvHD prophylactic strategies, and the potential impact of various AML relapse prevention therapy or treatments on GvHD.

The impact of epigenetic modifications on allogeneic hematopoietic stem cell transplantation

The field of epigenetics studies the complex processes that regulate gene expression without altering the DNA sequence itself. It is well established that epigenetic modifications are crucial to cellular homeostasis and differentiation and play a vital role in hematopoiesis and immunity. Epigenetic marks can be mitotically and/or meiotically heritable upon cell division, forming the basis of cellular memory, and have the potential to be reversed between cellular fate transitions. Hence, over the past decade, there has been increasing interest in the role that epigenetic modifications may have on the outcomes of allogeneic hematopoietic transplantation and growing enthusiasm in the therapeutic potential these pathways may hold. In this brief review, we provide a basic overview of the types of epigenetic modifications and their biological functions, summarizing the current literature with a focus on hematopoiesis and immunity specifically in the context of allogeneic hematopoietic stem cell transplantation.