Enrica Antonia Martino

Background: mRNA‐based vaccines are emerging as a promising platform for cancer immunotherapy, including in hematologic malignancies. Current vaccine development has largely focused on antigen selection, mRNA engineering, lipid nanoparticle (LNP) formulation, and combination with established immunotherapies. However, increasing evidence indicates that the cellular and tissue distribution of antigen expression may critically influence the quality and durability of the immune response. In this context, the term “cellular pharmacology” refers to the principle that the pharmacodynamic effect of an mRNA vaccine is shaped not only by the encoded antigen and formulation but also by the cell types in which antigen expression occurs. Objectives: Here, we propose a cellular pharmacology framework for mRNA vaccines in hematologic malignancies, moving beyond the traditional dendritic‐cell‐centric model and considering antigen expression as a determinant of immune activation, tolerance, and T‐cell exhaustion. Discussion: Three functionally distinct compartments can be considered: professional antigen‐presenting cells, immunogenic non‐immune cells at the injection site, and tolerogenic tissues, particularly hepatocytes. This tripartite model is intended as a simplified functional framework rather than a complete anatomical or cellular classification. While antigen expression in dendritic cells and other antigen‐presenting cells supports effective T‐cell priming, antigen production by skeletal myocytes and stromal cells may provide a sustained source of antigen for uptake and cross‐presentation. Importantly, myocytes should not be regarded as professional antigen‐presenting cells, but rather as potential antigen‐producing cells whose antigens can be presented by professional APCs. Conversely, hepatic antigen expression may promote peripheral tolerance and impair antitumor CD8+ T‐cell responses. Recent preclinical evidence indicates that microRNA‐guided hepatocyte detargeting may enhance vaccine‐induced immunity and tumor control in experimental models, although its clinical relevance in hematologic malignancies remains to be established. This concept may be particularly relevant in hematologic malignancies, characterized by disseminated disease, chronic antigen exposure, immune dysfunction, and frequent treatment‐related organ vulnerability. We discuss how cellular targeting could be incorporated into mRNA vaccine strategies for lymphomas, acute leukemias, chronic lymphocytic leukemia, and multiple myeloma, as well as into combination approaches with CAR‐T cells, bispecific antibodies, and immune checkpoint inhibitors. Conclusions: The therapeutic potential of mRNA vaccines in hematologic malignancies may depend not only on the antigen encoded but also on the cellular compartment in which it is expressed. Incorporating tissue biodistribution and cell‐type specificity into vaccine design could represent a new strategy to improve immunogenicity while limiting tolerogenic signals and potentially reducing unwanted tissue exposure. At present, however, hepatocyte detargeting should be considered a promising and testable translational strategy rather than a clinically validated approach. Prospective clinical studies integrating biodistribution, immune correlates, and tissue‐specific antigen expression will be essential to translate this cellular pharmacology concept into clinical practice.

Despite the development of robust prognostic biomarkers for risk stratification in newly diagnosed diffuse large B-cell lymphoma (DLBCL), namely international prognostic index (IPI), cell-of-origin (COO), circulating tumor DNA (ctDNA) and molecular clusters, none of these capture potential host-related features. In this study, untargeted plasma metabolomics was performed in a discovery cohort of 96 newly diagnosed R-CHOP-treated DLBCL patients. The key finding was validated in an independent cohort of 42 DLBCL with comparable clinical characteristics and outcomes. None of the 280 identified plasma metabolites was associated with COO classification subtypes. Conversely, the metabolomic profile appeared to show variations across ctDNA-defined molecular clusters. After an elastic net regression-based survival analysis, 2-hydroxybutyric acid (2HB) was selected as the only endogenous metabolite to be associated with worse progression-free survival (PFS) in the discovery cohort. The impact of 2HB levels on PFS was confirmed in the validation cohort. Also, 2HB levels (HR 2.09, 95% CI 1.04-4.19, p=0.04) maintained an independent association with shorter PFS when adjusted for higher ctDNA levels (HR 2.08, 95% CI 1.06-4.08, p=0.03). Therefore, 2HB and ctDNA levels were included in a two-factor prognostic score based entirely on minimally invasive plasma-derived biomarkers. This hypothesis-generating score improved outcome prediction compared with ctDNA assessment alone and enabled the identification of high-risk patients who might benefit from early restaging and potential treatment intensification (24-month PFS 28.8%). In conclusion, plasma metabolomics revealed a prognostically relevant role and 2HB sorted out as a potential host-related biomarker able to refine risk stratification in newly diagnosed DLBCL.

The therapeutic landscape for older adults with acute myeloid leukemia (AML) has undergone a major paradigm shift with the advent of lower‐intensity targeted regimens, particularly hypomethylating agents combined with venetoclax. As treatment transitions from acute induction to prolonged, multi‐cycle administration, clinical success increasingly depends on the patient's capacity to sustain repeated cycles, manage cytopenias and infections, and maintain functional independence. Current precision oncology models excel at characterizing the leukemic clone via cytogenetics, genomics, and measurable residual disease (MRD); however, they provide limited insight into the patient's underlying biological reserve. In this perspective, we propose host fitness as a critical, complementary dimension of precision medicine in older AML. Host fitness is a dynamic, multidimensional construct encompassing functional reserve, body composition, nutritional status, immune competence, inflammatory burden, and metabolic resilience. Moving beyond traditional performance status and simplistic metrics like body mass index, longitudinal assessment of host fitness aims to identify actionable vulnerabilities, guide targeted supportive interventions, and optimize treatment persistence. Integrating continuous host‐fitness evaluation with clonal profiling establishes a dual host–tumor precision‐medicine framework designed to maximize therapeutic efficacy while preserving patient resilience and quality of life.

Mitochondria are increasingly recognized as dynamic regulators of cancer-cell adaptation, immune function, and therapeutic response. Beyond their canonical role in energy production, mitochondrial metabolism, dynamics, quality control, and stress signaling influence tumor-cell survival and the capacity of immune effector cells to sustain antitumor activity within the tumor microenvironment. In this narrative review, we examine mitochondrial fitness as a multidimensional functional property encompassing bioenergetic capacity, metabolic flexibility, redox homeostasis, mitochondrial quality control, and adaptation to cellular and therapeutic stress. We propose the mitochondrial functional immune checkpoint as a conceptual framework linking mitochondrial fitness in malignant and immune cells to tumor–immune interactions and immunotherapy response. We discuss how mitochondrial metabolic plasticity, mitochondrial stress and mtDNA signaling, reactive oxygen species, mitochondrial dynamics, and intercellular mitochondrial transfer contribute to immune escape and treatment resistance. We further examine the relevance of mitochondrial fitness to immune checkpoint blockade, CAR-T-cell therapy, and T-cell-redirecting bispecific antibodies, with particular attention to hematological malignancies, including acute myeloid leukemia and multiple myeloma, while incorporating selected evidence from solid tumors to highlight shared mitochondrial mechanisms and their broader oncologic relevance. Finally, we discuss emerging strategies for mitochondrial targeting and functional mitochondrial profiling and their potential integration with established molecular and measurable residual disease assessments. Current evidence supports mitochondrial biology as a complementary dimension of precision oncology, although important challenges remain regarding context dependence, biomarker standardization, therapeutic selectivity, and preservation of immune-cell fitness. Prospective studies are needed to determine whether functional mitochondrial profiling can improve patient stratification and guide rational therapeutic combinations that selectively exploit tumor mitochondrial vulnerabilities while preserving effective antitumor immunity.

Summary: The extensive use of lenalidomide (Len) in the first‐line treatment of multiple myeloma (MM) has resulted in an increased frequency of patients who have been exposed or are refractory to Len (Len‐R) at first relapse. However, the outcome of Len‐R patients treated at first relapse after autologous haematopoietic stem cell transplantation (AHSCT) remains unclear. The aim of this real‐life study is to evaluate the effectiveness of the regimens licensed in Italy and used in a cohort of patients who relapsed during Len maintenance after AHSCT. We collected 306 patients with these features. Considering the different regimens used, most patients received isatuximab–carfilzomib–dexamethasone (Isa‐KD) (45.4%) followed by daratumumab–pomalidomide–dexamethasone (D‐PD) (19.3%) and daratumumab–bortezomib–dexamethasone (D‐VD) (12.4%). Overall, a reduced progression‐free survival (PFS) and overall survival (OS) were observed in patients with high‐risk disease features at relapse, including high lactate dehydrogenase (LDH) ( p = 0.0003 and p < 0.0001), International Staging System (ISS) ≥2 ( p < 0.0001 and p < 0.0001) and early relapse (p = 0.0017 and p = 0.0009). Considering the type of treatment, anti‐cluster of differentiation 38 (CD38) monoclonal antibodies (anti‐CD38 MoAb)‐based regimen displayed improved survival compared to the other treatment, with Isa‐KD reporting the longest PFS (22.8 months). Our data in a homogenous cohort of Len‐R patients treated at first relapse demonstrated that the anti‐CD38 MoAb‐based combinations, particularly Isa‐KD, represented the standard of care before the approval of anti‐B cell maturation antigen (BCMA) immunotherapy.

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by the clonal expansion of myeloid blasts and the persistence of leukemic stem cells (LSCs) within a profoundly remodeled bone marrow (BM) microenvironment. Despite advances in molecular stratification and the introduction of targeted agents, long-term outcomes remain unsatisfactory, particularly in older and high-risk patients. Increasing evidence indicates that leukemogenesis and treatment resistance are critically sustained by a permissive immune milieu, in which LSCs, myeloid-derived suppressor cells, leukemia-associated macrophages, and dysfunctional T and NK cells shape an immunosuppressive “leukemic niche.” This evolving understanding has renewed interest in immune-based strategies capable of restoring effective antitumor immunity. Bispecific antibodies (bsAbs) are engineered molecules designed to engage AML-associated antigens while simultaneously recruiting and activating immune effector cells, most commonly T cells or NK cells. By promoting immune synapse formation independently of major histocompatibility complex expression and conventional co-stimulatory pathways, bsAbs can overcome several mechanisms of immune escape. In this review, we summarize the biological rationale for immunotherapy in AML, with a focus on the role of the BM microenvironment and immune dysregulation. We then discuss the structural and functional properties of IgG-like and non-IgG-like bsAbs, key antigenic targets such as CD33, CD123, CD70 and others, and the main T-cell- and NK-cell-engaging platforms under clinical investigation. Finally, we highlight emerging clinical data, principal toxicities, and the challenges of integrating bsAbs into existing treatment algorithms, including combinations with hypomethylating agents, BCL-2 inhibitors, and allogeneic stem cell transplantation. A deeper understanding of AML immune biology and antigen expression patterns will be essential to optimize bsAb design, maximize therapeutic benefit, and minimize on-target off-tumor toxicity.

Mitochondrial dynamics is a key regulator of cellular homeostasis, orchestrating metabolic reprogramming that fuels tumor progression and treatment resistance. In multiple myeloma (MM), however, the functional relevance of mitochondrial remodeling has not been fully defined. Using ultrastructural analyses, we reveal that MM cells display a highly fragmented mitochondrial network, a phenotype further exacerbated in both cell lines and primary MM cells resistant to proteasome inhibitors. Transcriptomic profiling across multiple patient-derived datasets consistently demonstrated upregulation of DNM1L gene, which encodes the mitochondrial fission GTPase DRP1, particularly in relapsed and refractory MM, and revealed a significant association with inferior overall survival. Disrupting mitochondrial fission, either through genetic targeting of DNM1L or pharmacologic inhibition of DRP1 with the selective small molecule inhibitor Drpitor1a, resulted in pronounced mitochondrial dysfunction, impaired oxidative phosphorylation, and potent anti-myeloma activity in vitro, culminating in a hybrid cell death program with a predominant apoptotic component accompanied by ferroptotic features. These effects were recapitulated in vivo in a bortezomib-resistant xenograft model, where either DNM1L depletion or DRP1 inhibition produced similar outcomes. Mechanistically, the transcription factor c-MYC upregulated DNM1L expression, and DRP1-dependent mitochondrial fragmentation sustained MYC-driven oxidative metabolism and lipid synthesis. Altogether, these findings establish aberrant mitochondrial fission as a pathogenic hallmark of MM and highlight DRP1 inhibition as a promising therapeutic approach, especially for relapsed or refractory disease.