Emerging antibody-based therapeutic modalities such as CAR-Ts and bispecific antibodies have proven highly efficacious in treating diseases, including hematological malignancies. However, the complex molecular architectures of these novel agents present significant challenges in their design and production, for which binding moieties with small size and favorable physicochemical properties may offer a promising solution. Single domain antibodies (sdAbs), typically derived from the heavy chain antibodies of camelids and cartilaginous fishes but increasingly from synthetic and other sources as well, are small (12-15 kDa), well expressed, and exhibit favorable physicochemical properties, making them ideal targeting domains for these new modalities. In this article, we review the origins and characteristics of sdAbs, along with recent studies on CAR-T cell therapies and bispecific antibodies for hematological malignancies that incorporate sdAbs into their constructs, with emphasis on their structures, binding properties, and therapeutic efficacies. Together, these developments underscore the promise of sdAb-based CAR-Ts and bispecific antibodies as next-generation therapeutics, with the potential to expand treatment options and improve outcomes in hematological malignancies and beyond.

Bispecific T cell engagers (bispecific TCEs) are engineered antibodies that redirect T cells to mediate tumor cell killing by simultaneously binding to CD3 on T cells and tumor-associated antigens. As of July 2025, ten bispecific TCEs are clinically available. The CD3-binding antibodies in these bispecific TCEs can be classified into 6 groups based on the amino acid sequence similarity across their 6 complementarity-determining regions (CDRs). Specifically, antibodies were assigned to the same family if their six CDRs-HCDR1-3 and LCDR1-3-exhibited ≥80% pairwise sequence identity upon multiple sequence alignment. Family 1, derived from OKT3-a mouse hybridoma generated by immunizing BALB/c mice with human T cells-includes only blinatumomab; Family 2, derived from SP34-a rhesus monkey (Macaca mulatta) derived hybridoma specific for human T cells-comprises 5 antibodies; and Family 6, derived from UCHT1-a mouse hybridoma generated by immunizing mice with human T cells-contains only tebentafusp. The origin of the remaining 3 antibodies has not been disclosed and they possess unique CD3-binding sequences. We classified them into their own distinct families (Families 3, 4, and 5). Interestingly, mosunetuzumab (Family 4) showed remarkably lower incidence of adverse events such as cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and infection compared to other bispecific TCEs even though its affinity for CD3ε was not significantly different. The epitopes of 4 antibodies in Family 2, teclistamab, talquetamab, glofitamab, and tarlatamab were previously defined to be located at the N-terminal region of CD3ε via hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis. In our in silico epitope prediction analysis, the N-terminal region was included in the epitope region of all bispecific TCEs regardless of their family. Blinatumomab (Family 1) and tebentafusp (Family 6) did not bind to the CD3ε homolog of the cynomolgus monkey, whereas the other 8 bispecific TCEs did. This lack of cross-reactivity poses clear disadvantages in their preclinical development, particularly for toxicity and safety evaluation in nonhuman primate models.

The detection of measurable residual disease (MRD) in acute myeloid leukaemia (AML) has emerged as one of the strongest prognostic indications of adverse outcomes across different treatment settings and disease stages, independent of baseline genetic risk classification. Multiple techniques for MRD-assessment have been developed and clinically validated, including multiparameter flow cytometry (MFC) and molecular assays such as quantitative PCR (qPCR) and next-generation sequencing (NGS). These approaches have been incorporated into routine clinical practice to evaluate treatment efficacy and refine disease risk stratification. Beyond the prognostic significance, MRD monitoring offers a powerful tool for monitoring subclinical disease, enabling early relapse detection and influencing therapeutic decisions, including consolidation strategies, transplant conditioning, and pre-emptive interventions. In non-intensive treatment settings, MRD may help tailor treatment duration and identify patients eligible for therapy cessation. As the therapeutic landscape of AML continues to evolve with novel agents and strategies, the role and clinical applications of MRD are becoming increasingly relevant. This review summarizes current MRD assessment techniques, optimal measurement timepoints, and clinical applications across different therapeutic settings. We also highlight ongoing innovations and future directions that aim to fully integrate MRD into precision management of patients with AML.

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy defined by the clonal expansion of undifferentiated myeloid blasts with a block in differentiation and aberrant self-renewal. While recurrent genomic mutations are well-documented in AML, epigenetic dysregulation has emerged as an equally pivotal driver of leukemogenesis, a notion corroborated by the frequent recurrence of mutations in epigenetic regulators. Leukemic cells exhibit pervasive epigenetic alterations-including abnormal DNA methylation patterns, dysregulated histone modification, disrupted chromatin architecture and RNA-based regulatory mechanisms -which collectively rewire gene expression programs. These changes silence key differentiation genes and sustain self-renewal pathways, enforcing the developmental arrest and hyper-proliferation that are the hallmarks of AML. Importantly, epigenetic aberrations in AML are not merely downstream consequences of genetic lesions but actively contribute to the malignant phenotype. Somatic mutations frequently target epigenetic regulators (for example, DNA methyltransferases or histone modifiers), and these lesions cooperate with other genetic alterations to initiate and maintain the leukemic clone. Together, these insights highlight epigenetic dysregulation as a central mechanism in AML pathogenesis.

Therapy-related acute myeloid leukemia (tAML) and AML arising from previous hematologic disorders (secondary AML, sAML) share similar biological features, including karyotype abnormalities and gene specific mutations, patient-related risk factors. Older age and lower performance status also contribute to dimal prognosis, and dismal prognosis, both in terms of response rate and overall survival. However, these 2 entities significantly differ in leukemogenic trajectories. In this line, recent advances allowed for a better understanding of differential clonal progression processes in the broad landscape of sAMLs. Thus, in this manuscript, we reviewed clinical and biological characteristics of tAML and sAML, highlighting commonalities and divergent features and discussed classification aspects. We also gathered the newest evidence of leukemogenic trajectories leading from bone marrow failure syndromes, myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN) and MDS/MPN overlap syndromes to sAML, as well as leukemias arising from donors' cells in the setting of allogenic transplantation. Furthermore, we reviewed germline and acquired predisposition to leukemias and discussed the therapeutic landscape and future directions.

Acute myeloid leukemia (AML) is an aggressive blood cancer in which disease initiation and relapse are driven by leukemic cells with stem-like properties, known as leukemic stem cells (LSCs). The LSC compartment is highly heterogenous and this contributes to differences in therapy response. This heterogeneity is determined by genetic and nongenetic factors including somatic mutations, the cell of origin, transcriptional and epigenetic states as well as phenotypic plasticity. While this complicates the identification and eradication of LSCs, it also presents an opportunity to tailor therapeutic strategies to the phenotypic and functional states of LSCs present in a patient, exploiting their specific vulnerabilities. The emergence of single-cell multiomics technologies has transformed our ability to dissect cellular heterogeneity in AML, enabling simultaneous interrogation of genomic, transcriptomic, epigenomic and proteomic layers and providing high-resolution molecular snapshots of individual cells. In this review, we discuss causes and consequences of LSC heterogeneity, highlight advances in single-cell multiomics technologies to resolve it and outline how they can address shortcomings in our understanding of LSC heterogeneity and plasticity to revolutionize diagnostics and disease monitoring of AML.

Menin inhibitors are emerging as targeted therapies for acute leukemias with high HOXA gene expression. These leukemias harbor mutations including KMT2A-rearrangements, NPM1c mutations, NUP98-fusions, UBTF tandem duplications and potentially others. Mechanistically, each of these oncoproteins depend on the KMT2A:Menin interaction to maintain critical gene expression. Several Menin inhibitors have entered clinical trials and have shown impressive efficacy in heavily pretreated patients with acute myeloid leukemia (AML). Revumenib received FDA approval for patients with relapsed or refractory acute myeloid leukemia with KMT2A-rearrangements in November 2024. Despite the success of Menin inhibitors, leukemia progression due to therapeutic resistance is a common occurrence with monotherapy. Hence, current clinical trials focus on Menin inhibition in combination with chemotherapy and/or standard-of-care targeted therapies to potentially overcome or prevent resistance. Menin inhibitors are also being investigated in patients with newly diagnosed acute leukemia or as a maintenance therapy post allogeneic stem cell transplantation. This review provides an overview of the mechanism of action of Menin inhibitors and the disease subsets that show sensitivity. We explain the current understanding of genetic resistance, mediated by Menin mutations that reduce drug binding affinity, and the emerging understanding of other types of resistance. Ongoing clinical trials are summarized, and we discuss the future role of Menin inhibition as a potentially practice-changing treatment for up to 50% of patients with AML.

Immunotherapy has dramatically improved outcomes in lymphoid malignancies. In B cell cancers, CD19-directed CAR T cells and T-cell engagers have produced high remission rates and durable responses, now forming the cornerstone of treatment in many relapsed or refractory settings. In contrast, acute myeloid leukemia (AML) has not experienced a comparable breakthrough. To date, only antibody-drug conjugates have reached regulatory approval, with gemtuzumab ozogamicin approved in combination with intensive induction and consolidation therapy for newly diagnosed CD33-positive AML. This divergence is rooted in the biological and immunologic complexity of AML. Unlike B-cell malignancies with lineage-restricted surface markers such as CD19, AML lacks leukemia-specific antigens. Most targets are shared with normal hematopoietic progenitors, leading to on-target/off-leukemia toxicity. Moreover, AML exerts local and systemic immunosuppression through both tumor-intrinsic and microenvironmental mechanisms, limiting T-cell persistence and function. This review will introduce the current immunotherapy platforms under investigation in AML, starting with antibody-based approaches, followed by T-cell redirecting therapies, and culminating in an overview of immune resistance, the bone marrow microenvironment, and strategies toward personalized combinatorial immunotherapy. By synthesizing recent clinical data and mechanistic insights, including those from early CAR and T-cell engager trials, we aim to provide a translational framework for how immunotherapy might still reshape AML care-through integration of immune contexture of the bone marrow environment aiming for rational combinatorial approaches.

Germline predisposition syndromes to myeloid malignancies have been recognized increasingly over the last decade. Although many of these genetic syndromes present early in life, the age at which a hematopoietic malignancy develops can vary widely depending on the specific gene involved and its role in hematopoiesis. Herein, we aim to review age-related penetrance and phenotype of key germline predisposition syndromes including: SAMD9/9L, GATA2, inherited bone marrow failure syndromes, RUNX1, CEBPA, TP53, and DDX41. We describe optimal diagnostic strategies for these patients, and explain how recognition of germline predisposition allows for the development of optimal treatment plan for the affected individual and counseling of at-risk family members.

After decades of therapeutic inertia, the treatment of acute myeloid leukemia (AML) has seen remarkable improvements over the past ten years. Scientific discoveries have substantially enhanced the understanding of AML disease biology. The improved knowledge about leukemic transformation and disease mechanisms in this heterogeneous group of aggressive blood cancers has resulted in enhanced biologically defined risk prognostication and the development of novel targeted therapeutic agents. Many of these mechanism-based therapeutics have entered clinical development, with some getting approval for the treatment of specific genetically defined AML subgroups in patients fit or unfit for intensive chemotherapy-based treatment. As a result, the European LeukemiaNet (ELN) expert panel has established a distinct genetic risk stratification for AML patients undergoing less-intensive treatment, which incorporates targeted drugs (ELN 2024). The ELN 2022 risk categories, designed for predicting outcomes following intensive chemotherapy, did not adequately assess responses to these new regimens. In this review, we discuss the current state-of-the-art approaches in both intensive and less-intensive front-line treatments for AML, highlighting the most promising therapeutic innovations.

The landscape of acute myeloid leukemia (AML) diagnostics is undergoing a pivotal shift towards a transformative era, driven by the integration of artificial intelligence (AI). This review delves into the pivotal role of AI in reshaping AML diagnostics in the 21st century, highlighting advancements, challenges, and future prospects. AML, marked by the immediate need for accurate diagnosis and treatment, requires precise analysis against the complexity of various diagnostic methods such as cytomorphology, immunophenotyping, cytogenetics, and molecular testing. The introduction of AI in this field promises to address the critical need for rapid and standardized diagnostics, thereby enhancing patient care. AI technologies, including deep learning (DL) and machine learning (ML), are revolutionizing the interpretation of complex diagnostic data. With the use of AI-based models such as deep learning (DL) classifiers or automated karyotyping, promising tools do already exist. When it comes to reporting and reasoning, large language models (LLM) show their potential in efficient data processing and better clinical decision-making. This includes the use of large language models (LLMs) for generating comprehensive diagnostic reports that integrate multi-layered diagnostic information. However, there is a critical need for transparency and interpretability in AI-driven diagnostics. Explainable AI (XAI) models address this need building trust among clinicians and patients. Moreover, this review addresses the growing field of synthetic data that are becoming increasingly accessible due to advances in AI and computational technology. While synthetic data present a promising avenue for augmenting clinical research and potentially optimizing clinical trials in fields such as AML, their application requires careful ethical, regulatory, and methodological considerations. There are several limitations and challenges to consider regarding not only synthetic data but also AI models in general. This includes regulatory hurdles due to the dynamic nature of AI, as well as data privacy concerns and interoperability between different systems. In conclusion, AI has the potential to completely change how we diagnose and treat AML by offering faster, more accurate, and more comprehensive diagnostic insights. This potential is especially crucial for preserving knowledge in times of shortages of human experts. However, realizing this potential will require overcoming significant challenges and fostering collaboration between technologists and clinicians. As we move forward, the synergy between AI and human expertise will undoubtedly redefine the landscape of AML diagnostics, leading in a new era of precision medicine in hematology.

Over the past decades, the progressive identification of chromosomal abnormalities and gene mutations has transformed acute myeloid leukemia (AML) from a morphologically defined disease into a genetically stratified malignancy. The coexistence and competition of multiple mutations within leukemic clones underscore the complexity of AML and the need for therapeutic strategies that address clonal interference and mutational synergy. Molecular profiling now offers a more accurate definition of AML ontogeny, surpassing clinical history and revealing biologically and prognostically distinct subtypes. At the same time, new classifications focusing on genetic characteristics have enabled a more coherent and clinically meaningful categorization of the disease. These advances have contributed directly to risk stratification and treatment selection, and thus to more appropriate management.

Approximately 95% of lymphoplasmacytic lymphomas (LPL) are IgM secreting and are characterized as Waldenstrom Macroglobulinemia (WM). Conversely, non-IgM secreting LPL are rare. As part of the 12th International Workshop on WM (IWWM-12), a consensus panel of experts was tasked to develop recommendations for the management and response assessment of non-IgM LPL. The panel considered that in view of available molecular, pathological and clinical data, non-IgM LPL should be considered as a separate sub-entity of LPL. The panel further recommended that the IWWM-2 consensus criteria used for IgM LPL (WM) treatment initiation, should also be used for non-IgM LPL and be independent of IgG or IgA paraprotein level unless symptomatic hyperviscosity is present. The panel agreed that based on current evidence, there is insufficient data to support a different clinical management for non-IgM vs IgM (WM) LPL. Moreover, the panel advised that patients with non-IgM LPL should be treated in a similar manner to patients with IgM LPL independent of MYD88 mutation status until more is known about its impact on treatment outcomes for non-IgM LPL patients. The panel therefore recommends the use of the IWWM-11 IgM LPL (WM) response criteria for cases of non-IgM LPL with a monoclonal IgA or IgG paraprotein component, but creating a specific panel to develop formal response criteria for this LPL subset was also recommended.

Over the last decade, covalent Bruton tyrosine kinase (BTK) inhibitors have become a standard option for treating patients with symptomatic Waldenström Macroglobulinemia (WM) in the frontline or relapsed settings. However, the definition of intolerance and resistance to covalent BTK inhibitors has not been established. Understanding the best approaches to managing such patients is crucial to avoiding premature abandonment of effective therapy or pursuing futile therapies unlikely to be effective in controlling symptomatic disease progression. With the advent of noncovalent BTK inhibitors and BCL2 antagonists, in addition to clinical trials evaluating phospholipid-drug conjugates, antibody-drug conjugates, and bispecific antibodies, the present Consensus Panel 5 aims to establish working definitions for intolerance and resistance to covalent BTK inhibitors, as well as provide strategies to identify and manage these issues not infrequently encountered in clinical practice.

Histological transformation (HT) in Waldenström's macroglobulinemia (WM) is a rare complication and despite growing literature in the last years, no consensus recommendations exist. Consensus Panel 6 (CP6) of the 12th International Workshop on Waldenström's Macroglobulinemia (IWWM-12) was convened to review the current data on transformed WM and make recommendations on its diagnosis and management. The key recommendations from IWWM-12 CP6 included: (1) in case of suspected HT, tissue biopsy is the gold standard for diagnosis; (2) the initial work-up should comprise FDG-PET/CT for the evaluation of disease extent and, for patients with clinical suspicion or for high-risk patients (CNS-IPI, multiple and/or specific extranodal involvements), cerebrospinal fluid examination and brain MRI; (3) standard dose chemoimmunotherapy (CIT) such as R-CHOP (rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone) or R-CHP + polatuzumab vedotin are the preferred front-line regimen; (4) CNS prophylaxis and consolidation with autologous stem cell transplantation (SCT) can be considered according to de novo diffuse large B-cell lymphoma (DLBCL) guidelines; (5) T-cell-engaging therapies (CAR T-cells, bispecific antibodies) should be used in the relapse/refractory setting according to international guidelines for DLBCL and local access to these therapies. Key unanswered questions include the role of TP53 abnormalities and CXCR4 mutations on the risk of HT, the prognostic role of clonal relationship between WM and HT, the optimal front-line therapy (addition of novel agents to CIT, dose-intensive CIT, consolidation with autologous SCT), and the sequence of T-cell-engaging therapies. International collaboration and consideration of and inclusion in clinical trials is critical to address these issues in a rare patient population.

The IgM-related peripheral neuropathies (IgM-PN) are a group of chronic disorders characterized by the presence of monoclonal IgM that may be associated with one of several diseases affecting the peripheral nerves. In many cases, there is a monoclonal IgM associated with activity against neural targets, leading to progressive peripheral nerve demyelination. Neurological symptoms in this setting can also result from direct invasion of the peripheral or central nervous system by lymphoplasmacytic cells (neurolymphomatosis and Bing-Neel syndrome respectively) or via other mechanisms (for example AL amyloid deposition or cryoglobulinemic vasculitis). There is an expanding array of treatment options, but high-quality data are sparse. Diagnostic accuracy is important and needs collaboration between hematologists and neuromuscular specialists to determine the sequence and intensity of investigations. Appropriate causal attribution to the IgM disorder is essential to enable the correct therapeutic intervention. The aims of treatment intervention should be clear and realistic. Consistent and clinically meaningful measures are needed to capture treatment success. Despite therapeutic advances, many patients experience persistent disability, highlighting the need for further research.

Consensus panel 2 from the 12th International Workshop on Waldenstrom Macroglobulinemia was tasked with updating the guidelines on the diagnosis and management of patients with Bing-Neel syndrome (BNS). In this panel we have summarized the clinical symptoms that may be present with BNS, discussed the criteria required for diagnosis of BNS, made recommendations for follow-up imaging, and proposed revised guidelines for response assessment in BNS. The key recommendations from the 12th International Workshop on WM (IWWM-12) Consensus panel 2 include: (1) the establishment of zanubrutinib as a standard therapy for treatment of BNS; (2) recommendations on imaging and CSF evaluation during treatment and follow-up of BNS; and (3) revised response criteria in view of new data showing that malignant cells can persist in the CSF of many patients treated with BTK-inhibitors. New categorical response categories proposed include that for a Clinical Complete Response and Progressive Disease.

The Consensus Panel 3 (CP3) of the 12th International Workshop on Waldenström macroglobulinemia (IWWM-12) has reviewed and incorporated current data to make recommendations for the management of patients with high-risk WM (HR-WM). Recognizing the considerable heterogeneity in survival outcomes and identifying a subgroup of patients with a very poor prognosis, the key recommendations from CP3 include: (1) Risk stratifying patients with smoldering WM (SWM) and active (symptomatic) WM at diagnosis (2) Using the degree of i) bone marrow lymphoplasmacytosis, ii) serum beta-2 microglobulin (β2M) elevation, iii) IgM increase, iv) serum albumin decrease and the presence of wild-type MYD88 status markers that adversely dictate the time-to-progression from smoldering to active WM to the define HR-SWM. (3) Among patients with active WM, the presenting parameters: advanced chronological age, low serum albumin, elevated serum lactate dehydrogenase, elevated β2M and the presence of TP53 alterations (TP53 mutation or deletion 17p) unfavorably impact the prognosis and should be utilized to risk-stratify patients into the HR category. (4) The panel encourages screening for genetic alterations at diagnosis, prior to initiating therapy and also with rapidly advancing disease or refractoriness to ongoing therapy, which might result from clonal evolution. Although limited data directing the selection and sequencing of therapies exist, a risk-adapted approach and clinical trial participation for patients with HR-WM are highly encouraged.