Non-Hodgkin lymphomas (NHLs) are the most common hematological malignancies worldwide. Among these, B-cell lymphomas (B-NHLs) are the second leading cause of death in hematologic neoplasms.

In this study, a detailed immunophenotypic analysis of lymphocytes in the bone marrow aspirate (BMA) of 75 patients with four different subtypes of B-NHLs was performed at diagnosis. The samples were analyzed by flow cytometry (FC) using a stain-lyse-no wash technique and a comprehensive six-color antibody panel.

Our data showed a different trend in the percentage values of the distinct lymphocyte subsets, which did not seem to correlate with a worse prognosis, except for B cells in diffuse large B-cell lymphoma (DLBCL), which were significantly higher in stage IV than in stages II and III. ROC curve analysis showed that the B-cell percentage value could be used to predict the stage of the disease. Total lymphocytes and B cells were greater in lymphomas that presented a lower percentage of disease progression, specifically mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL). In contrast, natural killer (NK) and T cells showed higher values in DLBCL and follicular lymphoma (FL), which progressed more frequently. Interestingly, in DLBCL patients with higher percentage values of double positive (DPT) and helper T cells (Th), we observed a good prognosis. Specifically, univariate Cox regression analyses indicated that a higher value of Th cells at diagnosis was a better prognostic predictor in patients with DLBCL.

These preliminary findings encourage us to further investigate the role of lymphocyte subpopulations in B-cell NHL.

Onconephrology is an expanding subspecialty focused on the management of cancer patients with renal injury. This study used a comprehensive bibliometric analysis to emphasize the need for cooperation between oncologists and nephrologists, exploring current trends and future research areas in onconephrology.

Relevant literature on onconephrology published between 1 January 2000 and 27 April 2024 was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection, followed by manual screening. Bibliometric analyses were performed using CiteSpace, VOSviewer, and Bibliometrix software.

A total of 1,853 publications, including 1,647 articles and 206 reviews, by 11,606 authors from 2,757 institutions in 73 countries, were analyzed. Annual publications generally follow a steadily increasing trend, ranging from 25 to 161 documents. The United States (n = 464), The University of Texas MD Anderson Cancer Center (n = 39), Meletios A. Dimopoulos (n = 21), and Nephrology Dialysis Transplantation (n = 35) were the most productive country, institution, author, and journal, respectively. Immune checkpoint inhibitors, glomerular filtration rate, and cisplatin were clusters of highly cited references after 2015. Oxaliplatin, calcium, open-label, and thrombotic microangiopathy were trending topics after 2020. Outcome, acute kidney injury, immunotherapy, and chronic kidney disease were keyword bursts that persisted through 2024.

Current research of onconephrology is focusing on chemotherapeutic nephrotoxicity, kidney function assessment, dosing of chemotherapeutic agents in chronic kidney disease, glomerular disease in cancer, immunotherapy, and electrolyte disturbances. Future directions in this field include clinical trials and thrombotic microangiopathy.

Decentralized or point-of-care (POC) manufacture of CAR-T cells is a potential strategy to improve accessibility and reduce cost and logistic challenges. A total of 10 relapsed/refractory patients (B cell acute lymphoblastic leukemia [B-ALL] N = 6, diffuse large B cell lymphoma [DLBCL] N = 4) were enrolled in this POC phase 1 study. Chimeric antigen receptor (CAR)-T cells were manufactured using the fully automated CliniMACS Prodigy system. The CAR-T cell products had a median 15-fold expansion with a median transduction rate of 38%. The immunophenotypic characterization indicates a significant increase in central memory and effector T cells. All the patients were infused with fresh CAR-T cells. Complete remission rates were 100% for B-ALL and 50% for DLBCL. At a median follow-up of 15 months, 8 of 10 patients remain without disease progression. Adverse events reported were cytokine release syndrome grade 2 or higher in 2 of 10 patients. None of the patients developed immune effector cell-associated neurotoxicity syndrome. Late hematological toxicity of grade 2 or higher was noted only in one patient. Evaluation of health care resource utilization demonstrates that the median cost was US$12,724, while the manufacturing cost was US$35,107. Our data highlight the safety, efficacy, low cost, and potential to enhance the accessibility of CAR-T cell therapy in low- and middle-income countries through a fully automated and closed manufacturing platform.

Various gene-modified cell therapies have been investigated in clinical trials, among which chimeric antigen receptor (CAR)-T cell therapy has been approved for the treatment of B cell tumors and has shown remarkable therapeutic effects. However, challenges, such as, cancer recurrence and manufacturing issues remain. To overcome such limitations, we investigated whether combining CAR-T cells with tolinapant, an inhibitor of apoptosis proteins (IAP) antagonist with immunomodulatory activity, could enhance the anti-tumor effect. Tolinapant induced cancer cell death in the presence of TNF-α. Tumor killing by CAR-T, TCR-T or CÊNK cells was enhanced by tolinapant in vitro in a TNF-α-dependent manner. TNF-α secreted from CAR-T cells, in the presence of tolinapant, also induced cell death of antigen-negative cancer cells not in cell-cell contact with CAR-T cells. Addition of tolinapant potentiated efficacy of not only two different CAR-T, but also TCR-T and CAR-NK cells in vivo. Tolinapant treatment led to faster expansion of stimulated CAR-T cells in vitro and in vivo. Our study suggests that the combination of tolinapant improves the efficacy of cell-based cancer therapies by inducing both cancer cell death and CAR-T cell proliferation. This combination therapy may overcome the current limitations of cell-based therapies and enhance their anti-cancer effect.

Leveraging the capacity to precisely manipulate and analyze individual cells, single-cell technology has rapidly become an indispensable tool in the advancement of cell-based drug delivery systems and innovative cell therapies. This technology offers powerful means to address cellular heterogeneity and significantly enhance therapeutic efficacy. Recent breakthroughs in techniques such as single-cell electroporation, mechanical perforation, and encapsulation, particularly when integrated with microfluidics and bioelectronics, have led to remarkable improvements in drug delivery efficiency, reductions in cytotoxicity, and more precise targeting of therapeutic effects. Moreover, single-cell analyses, including advanced sequencing and high-resolution sensing, offer profound insights into complex disease mechanisms, the development of drug resistance, and the intricate processes of stem cell differentiation. This review summarizes the most significant applications of these single-cell technologies, highlighting their impact on the landscape of modern biomedicine. Furthermore, it provides a forward-looking perspective on future research directions aimed at further optimizing drug delivery strategies and enhancing therapeutic outcomes in the treatment of various diseases.

Multiple myeloma (MM) is a hematological malignancy characterized by abnormal proliferation of clonal plasma cells, which is usually confined to the bone marrow (BM). But some malignant plasma cells grow independently of the BM, called extramedullary disease (EMD). With the clinical application of proteasome inhibitors, immunomodulators, monoclonal antibodies, and hematopoietic stem cell transplantation, the overall survival of MM patients has been significantly improved, but the survival of patients with EMD is still worse than that of non-EMD patients. There are currently no specific treatment options for EMD. chimeric antigen receptor T (CAR-T) cell therapy has brought a new era of immunotherapy. The application of CAR-T has significantly benefited many MM patients, and CAR-T may be a new hope for patients with EMD in the future. This review retrospectively summarizes the mechanism and prognosis of EMD, focusing on the application and potential of CAR-T in the treatment of EMD. It is hoped that this review can provide ideas for the treatment of EMD with CAR-T in the future.

Extracellular vesicles (EVs) play a vital role in intercellular communication within the tumor microenvironment (TME). These vesicles, secreted by tumor cells, contain proteins, lipids, and nucleic acids that significantly influence immune responses, particularly impacting T-cell function. In cancer, T cell dysfunction and exhaustion-marked by reduced proliferation, diminished cytokine production, and impaired cytotoxic activity-are key barriers to effective immune responses. Tumor-derived extracellular vesicles (TEVs) contribute to this dysfunction by carrying immunosuppressive molecules, such as transforming growth factor-beta (TGF-β) and various microRNAs (miRNAs). These TEV-mediated mechanisms promote T cell exhaustion and foster a broader immunosuppressive environment, enabling tumor progression and immune evasion. Furthermore, TEVs have been implicated in resistance to cancer immunotherapies, including immune checkpoint inhibitors and T cell therapies. Understanding the molecular pathways and cargoes within TEVs that drive T cell dysfunction is crucial for developing novel therapeutic strategies aimed at reinvigorating exhausted T cells, enhancing anti-tumor immunity, and improving cancer treatment outcomes.

Chimeric antigen receptor T cells recognizing CD19 (19CAR-T) cell therapy has achieved robust clinical efficacy when treating some hematological malignancies, but which patient subgroups benefit mostly remains elusive. Here we summarized the data of 541 patients from 30 clinical trials who underwent 19 CAR-T therapy and analyzed the different clinical responses between young (<44 years), middle-aged (45-59 years) and elderly (>60 years) patients and found that the young patients showed a higher level of complete response (CR) rate. Therefore, we then summarize the advances of studies focusing on the effects of age on anti-tumor efficacy of CAR-T therapy and analyze the reasons for the low CR rate after CAR-T cell therapy in elderly patients with tumors, aiming to provide hints for oncologists to select the most suitable candidate for this cancer immunotherapy.

Therapy resistance is a major barrier to achieving a cure in cancer patients, often resulting in relapses and mortality. Heat shock proteins (HSPs) are a group of evolutionarily conserved proteins that play a prominent role in the progression of cancer and drug resistance. HSP synthesis is upregulated in cancer cells, facilitating adaptation to various tumor microenvironment (TME) stressors, including nutrient deprivation, exposure to DNA-damaging agents, hypoxia, and immune responses. In this review, we present background information about HSP-mediated cancer therapy resistance. Within this context, we emphasize recent progress in the understanding of HSP machinery, exploring the therapeutic potential of HSPs in cancer treatment.

The advent of chimeric antigen receptor (CAR) T cells has revolutionized the treatment landscape for hematologic malignancies, and emerging evidence suggests their potential in autoimmune diseases (AIDs). This article evaluates the early successes and future implications of B-cell-targeting CAR T-cell therapy in AIDs. Initial applications, particularly in refractory systemic lupus erythematosus, have demonstrated significant and durable clinical remissions, with accompanying evaluation of the immune system suggesting a so-called "reset" of innate inflammation and adaptive autoimmunity. This has generated widespread interest in expanding this therapeutic approach. CAR T cells offer unique advantages over other treatment modalities, including very deep B-cell depletion and unique therapeutic activity within inflamed tissues and associated lymphoid structures. However, the field must address key concerns, including long-term toxicity, particularly the risk of secondary malignancies, and future accessibility given the higher prevalence of AIDs compared with malignancies. Technological advances in cell therapy, such as next-generation CAR T cells, allogeneic off-the-shelf products, and alternative cell types, such as regulatory CAR T cells, are being explored in AIDs to improve efficacy and safety. In addition, bispecific antibodies are emerging as potential alternatives or complements to CAR T cells, potentially offering comparable efficacy without the need for complex logistics, lymphodepletion, and the risk of insertional mutagenesis. As the field evolves, cellular therapists will play a critical role in the multidisciplinary teams managing these complex cases. The transformative potential of CAR T cells in AIDs is undeniable, but careful consideration of safety, efficacy, and implementation is essential as this novel therapeutic approach moves forward.

Extracellular vesicles are membranous particles released by cells in physiological and pathological conditions. Their cargo is heterogeneous since it includes different biomolecules such as nucleic acids and proteins. Oncogenic alterations affect the composition of extracellular vesicles and model their content during cancer evolution.

This review provides an overview of the studies focused on extracellular vesicles as source of biomarkers in hematological malignancies. A special insight into extracellular vesicles-derived biomarkers as tools for evaluating the prognosis of hematological malignancies and their response to treatment is given.

Extracellular vesicles are a valuable source of biomarkers in hematological malignancies. However, the translation from the bench to the bedside is challenged by the lack of standardization of the preanalytical variables of the experimental workflow. The release of standard operating procedures and the validation of the extracellular vesicles-derived biomarkers in large cohort of patients will help in exploiting the potential of extracellular vesicles in the clinical setting.

Chimeric antigen receptor T cell (CAR-T)-based immunotherapies have reshaped the therapeutic landscape of cancer treatment, in particular for patients afflicted with leukemia. However, defects in CAR behaviors and clinical complications have hindered their widespread application across diverse cancer types. Chief among these defects is high tonic signaling, absent in native activating immune receptors, which accelerates T cell exhaustion and undermines treatment efficacy. We hypothesized that these limitations arise because current CAR architectures fail to replicate the modular design of native activating immune receptors, which integrate distinct receptor and signaling modules. This modular assembly is crucial for maintaining proper receptor regulation and function.

Therefore, we set forth to develop a modular chimeric antigen receptor leveraging the same assembly principles found in native activating immune receptors to reestablish the intrinsic safeguards in receptor expression and signaling.

The resulting Modular Actuation Receptor Complex (MARC) displayed surface expression levels akin to its native immune receptor counterpart, the NK cell receptor KIR2DS3, while eliminating tonic signaling. In a clinically relevant mouse leukemia model, MARC-T cells exhibited remarkable long-term persistence and a less exhausted phenotype compared with conventional CAR-T cells.

With its modular architecture, the MARC offers unparalleled opportunities for optimization and broad applicability across different cell types, paving the way for transformative advancements in cell-based therapies. This innovation holds immense promise as a next-generation therapeutic tool in clinical settings.

Chimeric antigen receptor (CAR)-modified NK (CAR-NK) cells are candidates for next-generation cancer immunotherapies. Here we generated CD19-specific CAR-NK cells with 4-1BB and CD3ζ signaling endo-domains (CD19-BBz CAR-NK) by transduction of cord blood-derived NK cells using baboon envelope pseudotyped lentiviral vectors and demonstrated their antitumor activity in preclinical B cell lymphoma models in female mice. We next conducted a phase 1 dose-escalation trial involving repetitive administration of CAR-NK cells in 8 patients with relapsed/refractory large B cell lymphoma (NCT05472558). Primary end points were safety, maximum tolerated dose, and overall response rate. Secondary end points included duration of response, overall survival, and progression-free survival. No dose-limiting toxicities occurred, and the maximum tolerated dose was not reached. No cases of cytokine release syndrome, neurotoxicity, or graft-versus-host disease were observed. Results showed an overall response rate of 62.5% at day 30, with 4 patients (50%) achieving complete response. The median progression-free survival was 9.5 months, and the median overall survival was not reached. A post hoc exploratory single-cell RNA sequencing analysis revealed molecular features of CAR-NK cells associated with therapeutic efficacy and efficacy-related immune cell interaction networks. This study met the pre-specified end points. In conclusion, CD19-BBz CAR-NK cells were feasible and therapeutically safe, capable of inducing durable response in patients with B cell lymphoma.

Allogeneic double-negative T-cell (DNT) therapy has emerged as a novel, off-the-shelf cellular treatment with clinical feasibility, safety, and promising efficacy against leukemia. However, the biology of DNTs is less well characterized, and how DNT therapy distinguishes from conventional γδ T-cell therapy remains unclear. Collectively, this hinders our ability to bolster DNT functionalities in cancer therapy. Here, we performed single-cell RNA sequencing with in vitro and in vivo functional analysis on DNTs. As a significant proportion of DNTs express Vγ9Vδ2 (Vδ2) TCR chain, we compared DNTs with donor-matched conventional Vδ2 T cells expanded with zoledronic acid.

Healthy donor-derived allogeneic DNTs and Vδ2 T cells were expanded ex vivo. Single-cell RNA sequencing analysis was performed on both cellular products to identify the transcriptional landscape and inferred cellular interactions within DNTs, followed by comparisons with donor-matched Vδ2 T cells. Unique cellular subsets found only in DNTs were depleted to identify their contributions to the overall efficacy of DNTs against acute myeloid leukemia. The anti-leukemic activity and in vivo persistence of DNTs and Vδ2 T-cells were explored using flow cytometry-based cytotoxicity assays, memory phenotyping, and xenograft models.

Despite a shared Vδ2 expression between cellular products, we identified unique cellular compositions in DNTs that contribute to distinct transcriptional and cellular communication patterns relative to the donor-matched Vδ2 T cells, including higher expression of genes identified in chimeric antigen receptor T cells that persist in patients with durable cancer-remission. Vδ2- DNTs exhibited strong persistence characteristics, and their presence promoted the cytotoxic capabilities of Vδ2+ DNTs in repeated stimulation assays. This unique genetic signature and diverse cellular composition of DNTs resulted in better overall ex vivo expansion, prolonged persistence, and superior anti-leukemic activity compared with Vδ2 T cells in vitro and in vivo.

These results highlight the unique transcriptional, cellular, and functional profile of human DNTs and support the continued clinical investigation of allogeneic DNT therapy. The data also provide a reference gene signature that may help improve the efficacy of other types of allogeneic adoptive cellular therapies.

ObjectiveTo evaluate the potential of chimeric antigen receptor T-cell (CAR-T) therapy in revolutionizing the treatment of systemic lupus erythematosus (SLE) and to outline necessary future steps for its implementation.MethodsA careful literature search was conducted for relevant English language papers on pubmed.ResultsPreliminary data suggest that CAR-T therapy could significantly improve SLE outcomes. Demonstrating remarkable clinical and serologic improvements in SLE patients, with all treated patients achieving remission and discontinuing conventional steroids and immunosuppressive drugs. To realize this potential, it is imperative to advance our understanding and application of CAR-T therapy. Rigorous research is necessary to validate current findings, and clinical trials must be conducted to assess both the short- and long-term efficacy and safety across diverse populations. Identifying appropriate patient populations is crucial, as CAR-T may also address compliance issues. Despite its current high cost, the financial burden is comparable to the long-term costs of severe SLE treatment. Strategies to reduce costs, including production efficiencies and outpatient treatment options, are under exploration. Early intervention could enhance its feasibility and impact on long-term prognosis.ConclusionCAR-T therapy holds promise for altering the prognosis of SLE and potentially offering a cure. However, substantial efforts are required to validate its efficacy, ensure safety, identify suitable patient cohorts, and reduce financial barriers. This development represents an exciting advancement in SLE treatment, necessitating urgent and focused research and clinical application.

Chimeric antigen receptor T cell therapy (CAR-T) cells represent a new generation of autologous, allogeneic and personalised cell-based therapies that have revolutionised the treatment of B cell haematological malignancies. Despite their significant effectiveness in treating challenging relapsed and refractory diseases, access to this cutting-edge treatment remains a critical issue globally, even in high income countries. To gain insights into these challenges, the Worldwide Network for Blood & Marrow Transplantation (WBMT) initiated a survey focused on the state of CAR-T and cellular therapy availability worldwide. The survey aimed to identify the accessibility, manufacturing capabilities, apheresis, accreditation, reimbursement, presence of regulatory frameworks and legal oversight of these cell-based therapies. The survey included questions on demographics, the respondent's centre, CAR-T availability, details about haematopoietic stem cell transplant programs, supply and indications for CAR-T, quality assurance, and information about other cell and gene therapy products beside CAR-T. Conducted online over three months in 2023, the survey garnered 181 complete responses from various geographical regions, from North America, Asia, Europe, South and Central America, Australia and New Zealand, and Africa. Our findings suggested a promising level of awareness and interest in CAR-T therapy globally, even in lower-income regions. However, survey respondents cited cost as the primary barrier to access, alongside infrastructure and governmental support issues. The survey also highlighted the varying reimbursement strategies across regions, with costs in Europe and North America being relatively similar while Asia showed more variability. There was also variability in the regulatory and accreditation frameworks associated with delivery of these novel therapies As CAR-T therapy continues to grow, innovative solutions such as global partnerships, in-house production, and the establishment of cellular therapy centres in developing countries are essential. Addressing the challenges of access requires a comprehensive approach that combines efforts to lower costs, enhance healthcare infrastructure, and foster international collaborations, ensuring that CAR-T therapy becomes available to all who need it.

While chimeric antigen receptor (CAR) T cell therapy has shown great success in hematologic malignancies, the effectiveness in solid tumors has been limited by several factors, including antigenic heterogeneity and the immunosuppressive nature of the tumor microenvironment (TME). In this review, we discuss the advancements made in clinical studies and challenges faced by CAR-T therapy for solid tumors. To enhance CAR-T cell efficacy in solid tumors, we explore strategies such as enhancing T cell persistence and cytotoxicity, targeting multiple antigens, and utilizing innovative allogeneic CAR-T cell manufacturing. Additionally, we highlight the potential benefits of combining CAR-T therapies with immune checkpoint inhibitors and other treatment modalities to overcome TME limitations. We remain optimistic about the future of CAR-T cell therapy in solid tumors, emphasizing the need for continued research to refine therapeutic approaches and address the clinical needs of patients with cancer.

Although anti-CD19 chimeric antigen receptor (CAR-T) cells demonstrate high response rates in relapsed/refractory B-cell lymphomas, a considerable proportion of patients eventually encounter disease progression or relapse. The short-term and long-term outcomes of CAR-T treatment are intricately linked to the tumor microenvironment (TME), wherein macrophages with polarized characteristics can exhibit either anti-tumorigenic or pro-tumorigenic roles. Despite evidence implicating the crucial involvement of macrophages in CAR-T cell-treated lymphoma, their dynamic distribution and immune function related to lymphoma progression remain poorly understood. Immunocompetent mice were utilized to establish syngeneic A20 lymphoma/leukemia models. The distribution and polarization of macrophages were detected using immunohistochemistry (IHC) and flow cytometry techniques. We observed that CD19 CAR-T therapy exhibited significant efficacy in protecting mice against lymphoma, leading to increased infiltration of macrophages into the tumor tissue. Notably, during remission stages, M1-like macrophages (CD11b+F4/80+C206-CD80+) were predominant, whereas in relapsed mice, there was a shift towards M2-like phenotypes (CD11b+F4/80+C206+CD80+). The transition from remissive to relapsed status was accompanied by a reduction in the M1/M2 ratio and a decrease in pro-inflammatory cytokines. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed differential expression levels of CD206 and CD163 between remissive and relapsed mice, while signaling pathways involving PI3K and STAT3 may contribute to the skewing towards M2 polarization. In summary, our findings highlight the dynamic transformation of macrophage polarization during different stages of lymphoma progression and underscore its potential implications for immunotherapeutic interventions.

Immunotherapy has gathered significant attention and is now a widely used cancer treatment that uses the body's immune system to fight cancer. Despite initial successes, its broader clinical application is hindered by limitations such as heterogeneity in patient response and challenges associated with the tumor immune microenvironment. Recent advancements in nanotechnology have offered innovative solutions to these barriers, providing significant enhancements to cancer immunotherapy. Nanotechnology-based approaches exhibit multifaceted mechanisms, including effective anti-tumor immune responses during tumorigenesis and overcoming immune suppression mechanisms to improve immune defense capacity. Nanomedicines, including nanoparticle-based vaccines, liposomes, immune modulators, and gene delivery systems, have demonstrated the ability to activate immune responses, modulate tumor microenvironments, and target specific immune cells. Success metrics in preclinical and early clinical studies, such as improved survival rates, enhanced tumor regression, and elevated immune activation indices, highlight the promise of these technologies. Despite these achievements, several challenges remain, including scaling up manufacturing, addressing off-target effects, and navigating regulatory complexities. The review emphasizes the need for interdisciplinary approaches to address these barriers, ensuring broader clinical adoption. It also provides insights into interdisciplinary approaches, advancements, and the transformative potential of nano-immunotherapy and promising results in checkpoint inhibitor delivery, nanoparticle-mediated photothermal therapy, immunomodulation as well as inhibition by nanoparticles and cancer vaccines.

Patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) have poor outcomes (complete response [CR] rates with standard salvage therapy gemcitabine plus oxaliplatin [GemOx], ∼30%; median overall survival [OS], 10 to 13 months). Patients with refractory disease fare worse (CR rate with salvage therapy, 7%; median OS, 6 months). Epcoritamab, a CD3×CD20 bispecific antibody approved for R/R DLBCL after ≥2 therapy lines, has shown promising safety and efficacy in various combinations. We report results from the phase 1b/2 EPCORE NHL-2 trial evaluating epcoritamab plus GemOx in autologous stem cell transplant (ASCT)-ineligible R/R DLBCL. Patients received 48 mg subcutaneous epcoritamab after 2 step-up doses until progression or unacceptable toxicity; GemOx was given once every 2 weeks for 8 doses. The primary end point was overall response rate (ORR). As of 15 December 2023, 103 patients were enrolled (median follow-up, 13.2 months; median age, 72 years). Patients had challenging-to-treat disease: ≥2 prior therapy lines, 62%; prior chimeric antigen receptor T-cell therapy, 28%; primary refractory disease, 52%; refractory to last therapy, 70%. ORR and CR rate were 85% and 61%, respectively. Median duration of CR and OS were 23.6 and 21.6 months, respectively. Common treatment-emergent adverse events were cytopenias and cytokine release syndrome (CRS). CRS events had predictable timing, were primarily low grade (52% overall, 1% grade 3), and resolved without leading to discontinuation. Epcoritamab plus GemOx yielded deep, durable responses and favorable long-term outcomes in ASCT-ineligible R/R DLBCL. This trial was registered at www.clinicaltrials.gov as #NCT04663347.

The anti-tumor function of engineered T cells expressing chimeric antigen receptors (CARs) is dependent on signals transduced through intracellular signaling domains (ICDs). Different ICDs are known to drive distinct phenotypes, but systematic investigations into how ICD architectures direct T cell function-particularly at the molecular level-are lacking. Here, we use single-cell sequencing to map diverse signaling inputs to transcriptional outputs, focusing on a defined library of clinically relevant ICD architectures. Informed by these observations, we functionally characterize transcriptionally distinct ICD variants across various contexts to build comprehensive maps from ICD composition to phenotypic output. We identify a unique tonic signaling signature associated with a subset of ICD architectures that drives durable in vivo persistence and efficacy in liquid, but not solid, tumors. Our findings work toward decoding CAR signaling design principles, with implications for the rational design of next-generation ICD architectures optimized for in vivo function.

In contrast to chimeric antigen receptor T cells, T cell receptor (TCR)-engineered T cells can target intracellular tumor-associated antigens crucial for treating solid tumors. However, most trials published so far show limited clinical activity. Here we report interim data from a first-in-human, multicenter, open-label, 3 + 3 dose-escalation/de-escalation phase 1 trial studying IMA203, an autologous preferentially expressed antigen in melanoma (PRAME)-directed TCR T cell therapy in HLA-A*02+ patients with PRAME+ recurrent and/or refractory solid tumors, including melanoma and sarcoma. Primary objectives include the evaluation of safety and tolerability and the determination of the maximum tolerated dose (MTD) and/or recommended dose for extension. Secondary objectives include the evaluation of IMA203 TCR-engineered T cell persistence in peripheral blood, tumor response as well as duration of response. A total of 27 patients were enrolled in the phase 1a dose escalation and 13 patients in the phase 1b dose extension. IMA203 T cells were safe, and the MTD was not reached. Of the 41 patients receiving treatment (that is, who started lymphodepletion), severe cytokine release syndrome was observed in 4.9% (2/41), and severe neurotoxicity did not occur. In the 40 patients treated with IMA203, an overall response rate consisting of patients with unconfirmed or confirmed response (u/cORR) of 52.5% (21/40) and a cORR of 28.9% (11/38) was observed with a median duration of response of 4.4 months (range, 2.4-23.0, 95% confidence interval: 2.6-not reached) across multiple indications. Rapid T cell engraftment and long-term persistence of IMA203 T cells were observed. IMA203 T cells trafficked to all organs, and confirmed responses were more frequent in patients with higher dose. T cell exhaustion was not observed in the periphery; deep responses were enriched at higher PRAME expression; and higher T cell infiltration resulted in longer progression-free survival. Overall, IMA203 showed promising anti-tumor activity in multiple solid tumors, including refractory melanoma. ClinicalTrials.gov identifier: NCT03686124 .

CAR-T cell therapy faces challenges in solid tumor treatment and hematologic malignancy relapse, among which the limited persistence of CAR-T cells and target antigen downregulation are prominent factors. Therefore, we engineered an NKG2D/CD28 chimeric co-stimulatory receptor (CCR), leveraging its broad ligand expression on tumors to enhance the antitumor activity of MSLN CAR and CD19 CAR-T cells.

We generated MSLN CAR-T and CD19 CAR-T cells co-expressing the NKG2D/CD28 CCR and assessed their antitumor efficacy in vitro and in vivo. CAR-T cell activation, differentiation, and exhaustion were analyzed over time following tumor antigen stimulation. Furthermore, a chronic antigen stimulation model was established using tumor cells with low antigen density to simulate the sustained antigenic pressure encountered in vivo treatment conditions.

Our study shows that NKG2D/CD28&CAR-T cells exhibit enhanced cytotoxicity against tumor cells, especially those with low antigen density, both in vitro and in vivo. Compared to conventional second-generation MSLN CAR or CD19 CAR-T cells, these dual-targeted NKG2D/CD28&CAR-T cells demonstrate superior sensitivity in recognizing and lysing low-density antigen-expressing lung cancer and leukemia cells, and they are capable of eradicating tumors with low-density antigen expression in vivo. Furthermore, the complementary co-stimulation provided by the 4-1BB and CD28 intracellular domains in the CAR and NKG2D/CD28 promotes cytokine secretion, reduces CAR-T cell exhaustion, and enhances the in vivo persistence of CAR-T cells, significantly improving their antitumor efficacy.

The combination of CAR and NKG2D/CD28 offers a potent strategy to enhance the cytotoxicity and durability of CAR-T cells. This approach is promising for improving therapeutic outcomes in solid and hematological tumors and preventing recurrence in tumors with low target antigen density.

Tumor antigens are crucial for T-cell mediated immunotherapy, but identified antigens for gliomas remain limited. Aberrant splicing variants are commonly expressed in tumors, resulting in unique tumor isoforms with potential antigenic properties. Herein, we analyzed multi-omics data from 587 glioma patients and assembled a library of putative tumor-enriched isoform antigens (TIA) and corresponding peptides presented on each HLA-I allele. We constructed an individual-specific TIA peptide candidate repertoire for each patient based on their TIA expression and HLA-I haplotypes. TIAs were highly expressed, enriched with glioma malignancy, and demonstrated strong HLA-binding affinity. We focused on periostin isoform-203 (POSTN-203), which was associated with poor survival of patients and contained multiple predicted HLA-restricted peptide epitopes. A selected HLA-A11-restricted peptide from POSTN-203 (POSTN-203A11) induced antigen-specific T-cell responses against both peptide-pulsed and POSTN-203-expressing glioma cells in an HLA-specific manner. Our findings highlight TIAs as a promising source of immunogenic antigens and POSTN-203 as a potential promising target for glioma immunotherapy.

The recent clinical success of genetically modified T-cell therapies underscores the urgent need to accelerate fundamental studies and functional screening methods in T lymphocytes. However, a facile and cost-effective method for efficient genetic engineering of T-cells remains elusive. Current approaches often rely on viral transduction, which is labor-intensive and requires stringent biosafety measures. Plasmid-based electroporation presents an affordable alternative, but remains underexplored in T-cells. Moreover, the availability of prototypical T-cell lines is limited. Here, we address these challenges by focusing on two immortalized murine T-cell lines, HT-2 and CTLL-2, which recapitulate key characteristics of primary T-cells, including cytotoxicity and cytokine-dependent proliferation. Alongside the widely used Jurkat T-cell line, HT-2 and CTLL-2 were successfully transfected with single or multiple genes with high efficiencies by means of optimized electroporation in a cuvette-based system. Notably, optimization of plasmid constructs enabled the delivery of large gene-of-interest (GOI) cargos of up to 6.5 kilobase pairs, as well as stable integration of a GOI into the genome via the Sleeping Beauty transposon system. We also developed advanced methodologies for CRISPR/Cas9-mediated gene editing in immortalized T lymphocytes, achieving knockout efficiencies of up to 97 % and homology-directed repair (HDR)-based targeted knock-in efficiencies of up to 70 %. We believe this optimized plasmid-based electroporation approach will contribute to advances in basic research on lymphocyte biology, as well as providing a practical, cost-effective tool for preclinical studies of T-cell therapies.

Chimeric antigen receptor (CAR) T cell therapy stands as a transformative advancement in immunotherapy, triumphing against hematological malignancies and, increasingly, autoimmune disorders. After a decade of relatively modest results for solid tumors, recent clinical trials and patient reports have also started to yield promising outcomes in glioblastoma and other challenging solid tumor entities. This Perspective seeks to explore the reasons behind these latest achievements and discusses how they can be sustained and expanded through different strategies involving CAR engineering and synthetic biology. Furthermore, we critically analyze how these breakthroughs can be leveraged to maintain momentum and broaden the therapeutic impact of CAR T cells across a variety of solid tumor landscapes.

T-cell therapy advances have stimulated the development of bioprocesses to address the specialized needs of cell therapy manufacturing. During concentrated cell washing, the cells are frequently exposed to transiently reduced oxygen, temperature, pH, and nutrient levels. Longer durations of these conditions can be caused by process deviations or, if they are not harmful, be used to ease the scheduling of process stages during experiments as well as manufacturing.

To avoid unpredictable impacts on T-cell quality during bioprocessing, we measured the influences of such environmental exposures generated by settling 250 million activated human T cells per mL, for up to 6 h at temperatures from 4 to 37°C.

The measured glucose concentration decreased to as low as 0.5 mM and the pH to 6, while lactate increased up to 55 mM. The concentrated cell conditions at 37°C resulted in by far the greatest losses in viable cell numbers with, on average, only 58% and 41% of the cells recovered after 3 and 6 h, respectively. Likewise, their subsequent cell expansion cultures were substantially reduced even after only 3 h of exposure, and with decreased percentages of central memory T cells and increased percentages of effector memory and effector T cells. Although under similar environmental conditions at room temperatures, the negative impacts of high cell concentrations were greatly diminished for up to 3 h. At 4°C the transient conditions were less extreme, and the cells well maintained for 6 h.

Overall, when developing processes and devices for T-cell therapy manufacturing that involve concentrated cells, the results of this study indicate that more practically feasible room temperatures can be used for up to 3 h to obtain high viable cell recoveries whereas lower temperatures such as 4°C should be used if there is a need for more prolonged concentrated T-cell conditions.

Exosomes are extracellular vehicles that facilitate intra-cellular communication via transport of critical proteins and genetic material. Every exosome is intrinsically reflective of the cell from which it was derived and can even mimic effector functions of their parent cells. In recent years, with the success of CAR-T therapies, there has been growing interest in characterizing exosomes derived from CAR-T cells. CAR exosomes contain the same cytotoxic granules as their parent cells and have demonstrated significant anti-tumor activity in vitro and in animal models. Moreover, infusion of CAR exosomes in animal models did not generate cytokine release syndrome. Conversely, there are also novel bispecific antibodies which target tumor-derived exosomes in hopes of derailing immunosuppressive pathways mediated by exosomes produced from malignant cells. The two most promising examples include (a) BsE CD73 x EpCAM which binds and inhibits exosomal CD73 to suppress production of immunosuppressant adenosine and (b) BsE CD3 x PD-L1 which targets exosomal PD-L1 within the tumor microenvironment to guide cytotoxic T-cells towards tumor cells. As our understanding of exosome biology continues to evolve, opportunities for advances in cellular therapies will grow in tandem.

Prosurvival tumor necrosis factor receptor (TNFR) superfamily (TNFRSF) members on T cells, including 4-1BB, CD27, GITR, and OX40, support T cell accumulation during clonal expansion, contributing to T cell memory. During viral infection, tumor necrosis factor superfamily (TNFSF) members on inflammatory monocyte-derived antigen-presenting cells (APCs) provide a postpriming signal (signal 4) for T cell accumulation, particularly in the tissues. Patients with loss-of-function mutations in TNFR/TNFSF members reveal a critical role for 4-1BB and CD27 in CD8 T cell control of Epstein-Barr virus and other childhood infections and of OX40 in CD4 T cell responses. Here, on the 20th anniversary of a previous Annual Review of Immunology article about TNFRSF signaling in T cells, we discuss the effects of endogenous TNFRSF signals in T cells upon recognition of TNFSF members on APCs; the role of TNFRSF members, including TNFR2, on regulatory T cells; and recent advances in the incorporation of TNFRSF signaling in T cells into immunotherapeutic strategies for cancer.

Choosing appropriate delivery system for chemotherapeutic drugs as well as arranging the time spots for adoptive cells administrations is the key to achieve efficient combined chemo-adoptive cell therapy. Tumor-homing character makes adoptive immune cells appropriate targeting delivery carriers, but they are rarely used for chemtoxic payloads considering payloads internalization during administration which impairs adoptive cells. Herein, we frame adoptive NK cells using DNA scaffold with chemotherapeutic payloads fastened exterior, and achieves time-programmed drugs release and NK cell decapsulation to minimize side effects and enhance therapeutic effect. IL-21 nanoparticles are prepared by conjugating cytokine IL-21 with a GSH cleavable linker and act as anchor points for DNA scaffold assembly. Chemotherapeutic payloads are prepared by loading DOX/verapamil drugs to PLGA nanoparticles (PLGAdrugs NPs), and connected to the exterior of DNA scaffold with a ROS cleavable linker. Porous DNA scaffold protects NK cells functions from impairing by chemotherapeutic payloads, while guarantees efficient communication of NK cells with exterior environment to keep tumor homing capability. Reactive oxygen species (ROS) in tumor microenvironment releases PLGAdrugs NPs to perform chemotherapy, which subsequently generates a reductive environment to detach DNA scaffold for NK cell and IL-21 release to achieve combined chemo-adoptive cell therapy with enhanced therapeutic efficiency.

To validate and replicate an automated decentralized CD19 chimeric antigen receptor T (CAR-T) cell manufacturing process from healthy adult volunteers in an academic institution in a middle-income country.

Healthy volunteers were recruited and underwent leukapheresis with the continuous mononuclear cell (MNC) collection protocol. Clinical-grade CAR-T cell manufacturing was performed in a closed system using a second-generation CD19 vector with 41BB costimulatory domain. Quality control was assessed at different points in the production process with prespecified release criteria including product's aspect, sterility, cell viability, impurity, and quantity. The target dose formulation was 1 × 106/kg viable CAR-T cells per volunteer.

Five healthy volunteers were recruited, all donated adequate MNC units, and successfully underwent the manufacturing process. After T-cell culture harvest, the products contained a median CAR-T cell concentration of 16.5 × 106/mL (range, 7.7-22.2 × 106/mL), with a median transduction percentage of 44.7% (range, 39.2%-60.5%) and a median CD3+ cell viability of 97.7% (range, 90.4%-98.7%). Sterility was maintained throughout the manufacturing process. The quantity of cells harvested per kilogram of body weight was 24.6 MB-CART19.1 cells × 106/kg (range, 9.3-33.1 × 106/mL). The quality was similar in both fresh and cryopreserved units. Dose formulations were 1.1 CAR-T cells × 106/kg (range, 1.0-1.2 CAR-T cells × 106/kg).

Our study demonstrates an effective methodology with satisfactory and comparable performance to international reports. Point-of-care manufacturing is a feasible alternative to increase access to CAR-T cells in academic centers.

Organ transplantation is a lifesaving procedure, with 50,000 transplants happening every year in the United States. However, many patients harbor antibodies and B cells directed against allogeneic human leukocyte antigen (HLA) molecules, notably HLA-A2, greatly decreasing their likelihood of receiving a compatible organ. Moreover, antibody-mediated rejection is a significant contributor to chronic transplant rejection. Current strategies to desensitize patients non- specifically target circulating antibodies and B cells, resulting in poor efficacy and complications. Regulatory T cells (Tregs) are immune cells dedicated to suppressing specific immune responses by interacting with both innate and adaptive immune cells. Here, we genetically modified human Tregs with a chimeric anti-HLA antibody receptor (CHAR) consisting of an extracellular HLA-A2 protein fused to a CD28-CD3zeta intracellular signaling domain, driving Treg activation upon recognition of anti-HLA-A2 antibodies on the surface of alloreactive B cells. We find that HLA-A2 CHAR Tregs get activated specifically by anti-HLA-A2 antibody-producing cells. Of note, HLA-A2 CHAR activation does not negatively affect Treg stability, as measured by expression of the Treg lineage transcription factors FOXP3 and HELIOS. Interestingly, HLA-A2 CHAR Tregs are not cytotoxic towards anti-HLA-A2 antibody-producing cells, unlike HLA-A2 CHAR modified conventional CD4 + T cells. Importantly, HLA-A2 CHAR Tregs recognize and significantly suppress high affinity IgG antibody production by B cells from HLA-A2 sensitized patients. Altogether, our results provide proof-of-concept of a new strategy to specifically inhibit alloreactive B cells to desensitize transplant recipients.

Chimeric antigen receptor (CAR) T cell therapies have revolutionized B cell malignancy treatment, but subsets of patients with large B cell lymphoma (LBCL) experience primary resistance or relapse after CAR T cell treatment. To uncover tumor microenvironment (TME)-induced resistance mechanisms, we examined patients' intratumoral immune infiltrates and observed that elevated levels of immunoregulatory macrophages in pre-infusion tumor biopsies are correlated with poor clinical responses. CAR T cell-produced interferon-gamma (IFN-γ) promotes the expression of inducible nitric oxide synthase (iNOS, NOS2) in immunoregulatory macrophages, impairing CAR T cell function. Mechanistically, iNOS-expressing macrophages upregulated the p53 pathway, mediating apoptosis and cell cycle arrest in CAR T cells, while downregulating the MYC pathway involved in ribosome biogenesis and protein synthesis. Furthermore, CAR T cell metabolism is compromised by depletion of glycolytic intermediates and rewiring of the TCA cycle. Pharmacological inhibition of iNOS enhances the CAR T cell treatment efficacy in B cell tumor-bearing mice. Notably, elevated levels of iNOS+CD14+ monocytes were observed in leukaphereses of patients with non-durable response to CAR T cell therapy. These findings suggest that mitigating iNOS in tumor-associated macrophages (TAMs) by blocking IFN-γ secretion from CAR T cells will improve outcomes for LBCL patients.

The development of chimeric antigen receptor (CAR) T-cells, engineered from peripheral T-lymphocytes of a patient with lymphoma, in order to specifically target tumor cells, has been a revolution in adoptive cell therapy (ACT). As outlined in this review, ACT was initiated by hematopoietic cell transplantation (HSCT) and re-injection of interleukin-boosted tumor-infiltrating lymphocytes (TIL). The innovative venture of genetically modifying autologous peripheral T-cells to target them to cell-surface tumoral antigens through an antibody-derived structure (i.e. independent of major histocompatibility antigen presentation, physiologically necessary for T-cell activation), and intracytoplasmic T-cell costimulatory peptides, via a novel membrane CAR, has been an outstanding breakthrough. Here, focusing on B-cell hematological malignancies and mostly non-Hodgkin lymphoma, attention is brought to the importance of providing an optimal microenvironment for such therapeutic cells to proliferate and positively develop anti-tumoral cytotoxicity. This, perhaps paradoxically, implies a pre-infusion step of deep lymphopenia and deregulation of immunosuppressive mechanisms enhanced by tumoral cells. Fludarabine and cyclophosphamide appear to be the most efficient lymphodepletive drugs in this context, dosage being of importance, as will be illustrated by a thorough literature review.

Chimeric antigen receptor (CAR) NK cell therapy has emerged as a promising alternative to CAR T cell therapy, offering significant advantages in terms of safety and versatility. Here we explore the current clinical landscape of CAR NK cells, and their application in hematologic malignancies and solid cancers, as well as their potential for treating autoimmune disorders. Our analysis draws from data collected from 120 clinical trials focused on CAR NK cells, and presents insights into the demographics and characteristics of these studies. We further outline the specific targets and diseases under investigation, along with the major cell sources, genetic modifications, combination strategies, preconditioning- and dosing regimens, and manufacturing strategies being utilized. Initial results from 16 of these clinical trials demonstrate promising efficacy of CAR NK cells, particularly in B cell malignancies, where response rates are comparable to those seen with CAR T cells but with lower rates of severe adverse effects, such as cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and graft-versus-host disease (GvHD). However, challenges remain in solid tumor applications, where only modest efficacy has been observed to date. Our analysis reveals that research is increasingly focused on enhancing CAR NK cell persistence, broadening their therapeutic targets, and refining manufacturing processes to improve accessibility and scalability. With recent advancements in NK cell engineering and their increased clinical applications, CAR NK cells are predicted to become an integral component of next-generation immunotherapies, not only for cancer but potentially for immune-mediated diseases as well.

There is still an unmet need for the treatment of high-risk hematological malignancies. To date, allogeneic stem cell transplantation remains the only chance of cure. Most patients suffering from high-risk hematological malignancies are of an older age and often present with comorbidities. Moreover, patients achieving remission often suffer from early relapse. Amongst the different treatment options, sequential conditioning has yet to prove its value against other conditioning regimens. Sequential conditioning relies on a short course of intensive chemotherapy that is quickly followed by immunosuppressive conditioning before allogeneic stem cell transplantation. Here, we will try to determine which patients can benefit from sequential conditioning. Amongst the different sequential regimens, we will also try to assess if one regimen is better than all the others. Despite the several studies conducted on sequential conditioning, very few are prospective work and head-to-head comparisons are almost inexistant. Sequential conditioning also relies on the use of prophylactic donor lymphocyte infusion post-transplantation. Hence, limiting non-relapse complications is of primary importance to the allow administration of post-transplant treatment. In the era of new targeting therapies, is there still a place for sequential conditioning? Can patients benefit from an association of new therapeutic agents and sequential conditioning?

Adoptive cell therapy (ACT) can address an unmet clinical need for patients with relapsed/refractory acute myeloid leukemia (AML), but its effect is often modest in the setting of high tumor burden. In this study, we postulated that strategies to lower the AML apoptotic threshold will augment T cell killing of AML cells. BH3 mimetics, such as venetoclax, are a clinically approved class of compounds that predispose cells to intrinsic apoptosis by inhibiting anti-apoptotic mitochondrial proteins. We explored the anti-leukemic efficacy of BH3 mimetics combined with WT1-specific CD8+ T cells on AML cell lines and primary samples from patients with a diverse array of disease characteristics to evaluate if lowering the cellular apoptotic threshold via inhibition of anti-apoptotic mitochondrial proteins can increase leukemic cell sensitivity to T cell therapy. We found that the combination approach of BH3 mimetic and CD8+ T cells led to significantly increased killing of established AML lines as well as of adverse-risk primary AML leukemic blast cells. In contrast to the hypothesis that enhanced killing would be due to combined activation of the intrinsic and extrinsic apoptotic pathways, our data suggests that CTL-mediated killing of AML cells was accomplished primarily through activation of the intrinsic/mitochondrial apoptotic pathway. This highly effective combinatorial activity due to convergence on the mitochondrial apoptotic pathway was conserved across multiple AML cell lines and primary samples, suggesting that mitochondrial priming may represent a novel mechanism of optimizing adoptive cell therapy for AML patients.

In recent years, several global phase III trials have shown that combinations of immune checkpoint inhibitors (ICIs) offer superior efficacy and survival compared to multi-kinase inhibitors, establishing them as the gold standard for treating patients with advanced hepatocellular carcinoma (HCC). This success has led to investigations into expanding the use of immunotherapy into various other settings and populations, including neoadjuvant and adjuvant therapies, patients with decompensated liver function and those awaiting liver transplantation. Despite its proven efficacy, a significant number of patients still develop resistance to immunotherapy, highlighting the need for innovative strategies to address this challenge. Approaches aimed at enhancing tumour immunogenicity, such as combining immunotherapy with transarterial chemoembolization or radiation therapies, show significant promise. Additionally, novel immunotherapeutics - such as triplet therapy, bispecific antibodies, adoptive T-cell therapy and cancer vaccines - are in early development for HCC. These agents have demonstrated potential for synergistic effects with existing ICIs, with initial studies yielding positive outcomes. In this review, we offer our future perspective on immunotherapy, emphasizing emerging indications, novel combination strategies and the development of new immunotherapeutic agents. Overall, the future of immunotherapy in HCC is brimming with extraordinary potential, set to transform the treatment landscape and redefine the possibilities for managing this challenging disease.

Insufficient infiltration of cytotoxic lymphocytes to solid tumors limits the efficacy of immunotherapies and cell therapies. Here, we report a programmable mechanism to mobilize Natural Killer (NK) and T cells to breast cancer tumors by engineering these cells to express orphan and metabolite-sensing G protein-coupled receptors (GPCRs). First, in vivo and in vitro CRISPR activation screens in NK-92 cells identified GPR183, GPR84, GPR34, GPR18, FPR3, and LPAR2 as top enhancers of both tumor infiltration and chemotaxis to breast cancer. These genes equip NK and T cells with the ability to sense and migrate to chemoattracting metabolites such as 7α,25-dihydroxycholesterol and other factors released from breast cancer. Based on Perturb-seq and functional investigations, GPR183 also enhances effector functions, such that engineering NK and CAR NK cells to express GPR183 enhances their ability to migrate to, infiltrate, and control breast cancer tumors. Our study uncovered metabolite-based tumor immune recruitment mechanisms, opening avenues for spatially targeted cell therapies.

Measurable residual disease (MRD) is a powerful predictor of clinical outcomes in acute lymphoblastic leukemia (ALL). In addition to its clear prognostic importance, MRD information is increasingly used in clinical decision algorithms to guide therapeutic interventions. Although it is well established that achievement of MRD-negative remission is an important end point of ALL therapy, the prognostic and therapeutic implications of MRD in an individual patient are influenced by both disease-related factors (eg, cytomolecular risk) and assay-related factors (eg, sensitivity, specimen source, and timing of assessment), which add complexity to MRD-guided treatment decisions. In this review, we discuss the data supporting the use of MRD assessment in adult ALL and how this information can rationally inform clinical decisions, including selection of patients for MRD-directed therapies or allogeneic hematopoietic stem cell transplantation. We also discuss important interpretative challenges related to novel high sensitivity next-generation sequencing-based MRD assays, which are becoming increasingly used in clinical practice.