Despite great progress in understanding the genomic basis of immature T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma (T-ALL) and acute leukemias of ambiguous lineage (ALAL), there are still cases that lack defining genetic markers, complicating risk stratification and limiting targeted therapeutic options. Recent studies have shown that enhancer hijacking drives oncogene activation in approximately half of T-ALL cases, with the BCL11B enhancer frequently involved. Here, we describe a subtype of leukemia with a distinct gene expression signature, and immunophenotype characterized by positivity for immature (CD38), myeloid (CD13), T-lymphoid (cytoplasmic (c)CD3, CD7), and B-lymphoid markers (CD19, CD79a, CD10). This subtype is defined by the t(14;16)(q32;q24) translocation, which places the FOXF1 gene and its antisense long noncoding RNA gene FENDRR under the regulatory control of the BCL11B enhancer, leading to their ectopic transcriptional activation. Common concomitant genetic lesions are loss-of-function alterations of GATA3, CDKN2A/CDKN2B deletion and activating JAK/STAT and NOTCH1 pathway mutations. Patients were predominantly children and adolescents/young adults (AYA) and experienced poor treatment outcome. High-throughput drug screening of 176 compounds demonstrated efficacy of combined BCL2-family proteins and JAK/STAT signaling inhibitors. Additionally, the clinical use of tyrosine kinase inhibitors in some of these cases showed therapeutic efficacy. Collectively, these findings identify BCL11B-enhancer mediated deregulation of FOXF1/FENDRR as a hallmark of a subtype of high-risk lineage ambiguous leukemia that is potentially amenable to targeted therapeutic intervention.

Hypofibrinogenemia reduces experimental venous thrombosis, but the impact on arterial thrombosis remains unknown. In a cohort of patients with congenital fibrinogen disorders, 19/264 (~7%) patients developed arterial thrombosis, including 4/41 (~10%) patients with hypofibrinogenemia. However, 0/8 patients with fibrinogen aC-region truncation mutations reported arterial thrombosis over 286 patient-years. To analyze the impact of hypofibrinogenemia and the fibrinogen aC-region on arterial thrombosis, two mouse models were employed: 1) wildtype mice treated with lipid nanoparticles encapsulating siRNA against fibrinogen (siFga) and 2) Fga270/270 hypofibrinogenemic mice expressing fibrinogen with a truncated aC-region. While siFga-treated hypofibrinogenemic mice developed occlusive carotid artery thrombi similarly to controls, Fga270/270 mice displayed suppressed carotid thrombosis following FeCl3 challenge, indicating loss of the aC-region but not hypofibrinogenemia alone reduces arterial thrombosis. To determine if protection from arterial thrombosis in Fga270/270 mice was linked to loss of aC-region-platelet glycoprotein VI receptor (GPVI) interaction, platelet GPVI was depleted by JAQ1 antibody administration. JAQ1-treated wildtype mice were protected from arterial thrombosis following 5% FeCl3 but not 10% FeCl3 challenge. Interestingly, JAQ administration suppressed arterial thrombosis in siFga-treated mice but did not enhance protection in Fga270/270 mice following 10% FeCl3 challenge. Our studies suggest the fibrinogen aC-region promotes arterial thrombosis in hypofibrinogenemic conditions.

B cell receptor (BCR) signaling is a key determinant of chronic lymphocytic leukemia (CLL) pathophysiology. CD49d, the alpha4 subunit of the very late antigen-4 (VLA-4) integrin, can be activated by BCR signals; however, its role in modulating BCR functionality remains unknown. We used knockout mouse models and primary human CLL stratified by CD49d expression to address this aspect. CD49d was required for bone marrow infiltration and shaped bone marrow infiltration patterns and patient outcomes in human CLL. In TCL1 transplantation models, loss of CD49d abrogated bone marrow homing and leukemic cell positioning within splenic niches. At the cellular level, CD49d-deficient murine TCL1 transgenic cells and human CD49d-low CLL cells failed to form efficient immune synapses with antigen-presenting membranes. Transcriptome analyses identified CD49d-dependent regulation of actin-associated pathways and distinct signatures of BCR responsiveness in human and mouse. Consistently, CD49d-low human CLL cells displayed aberrant actin remodeling following BCR stimulation, and a second aggressive murine CLL model reproduced the actin and engraftment defects. Kinome profiling linked impaired antigen-induced BCR responses in CD49d-deficient murine cells to altered kinase activity, and pharmacological actin perturbation phenocopied CD49d loss. In human CD49d-low CLL cells, a desynchronization of BCR-related downstream Syk and PLCɣ activation was found. Mechanistically, the CD49d-BCR interplay involved their co-localization, and CD49d converged with BCR signaling on a focal adhesion kinase-actin axis. In summary, our findings establish CD49d as a key regulator of BCR functionality in CLL, linking integrins to cytoskeletal dynamics and antigen responsiveness.

The molecular classification of T-cell acute lymphoblastic leukemia (T-ALL) remains incomplete, limiting risk stratification and the development of targeted therapies. Enhancer hijacking is a critical oncogenic mechanism that deregulates proto-oncogenes by repositioning cis-regulatory regions via structural variants. Here, we performed an integrated analysis of pediatric and adult T-ALL and mixed phenotype acute leukemias (MPALs), using whole-genome and whole-transcriptome sequencing. This analysis identified a group of 14 patients with predominantly T-lineage neoplasms driven by a t(14;16)(q32;q24) translocation, harboring universal GATA3 mutations and CDKN2A/B deletions. Mechanistically, this translocation repositions the ThymoD locus downstream of BCL11B, causing monoallelic, ectopic overexpression of FENDRR and mesenchymal transcription factor genes FOXF1 and FOXC2, activating epithelial-mesenchymal transition (EMT) transcription signatures. Immunophenotypic and single-cell RNA-seq analyses revealed marked lineage ambiguity with myeloid and B-cell differentiation potentials specific to this subtype. Furthermore, functional analyses in CD34-positive cord blood cells demonstrated that FOXF1 overexpression promotes myeloid differentiation while suppressing T-cell differentiation, serving as a key factor for lineage specification. Clinically, this subtype was detected in 0.15-4.0% of T-ALL/MPAL cases depending on the cohort, showing a median age of 15 years and enrichment in adolescents and young adults (AYA). Importantly, patients with t(14;16)(q32;q24) have an extremely poor prognosis, showing a trend toward worse outcomes than high-risk groups such as KMT2A-rearranged early T-cell progenitor (ETP)-like, SPI1-rearranged, and LMO2 γδ-like T-ALLs. The unique molecular landscape and poor prognosis of patients with the t(14;16)(q32;q24) translocation underscore the need for the development of novel subtype-specific therapeutic approaches.

Briquilimab is a monoclonal antibody inhibiting stem cell factor (SCF) binding to CD117 (c-Kit). Based on preclinical data demonstrating the antibody clears hematopoietic stem and progenitor cells (HSPC) and myeloid malignant cells, we conducted a phase 1 trial examining briquilimab plus non-myeloablative fludarabine (flu) and total body irradiation (TBI) as conditioning for older adults with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) undergoing matched donor allogeneic hematopoietic cell transplantation (HCT). Briquilimab was infused 10-14 days before transplant day (TD) 0; fludarabine 30mg/m2 and TBI 2-3 Gy were administered on TD -4 to -2 and TD0, respectively. Graft-versus-host disease prophylaxis consisted of tacrolimus, sirolimus, and mycophenolate mofetil. Thirty-two patients enrolled (n=13 AML in complete remission [CR], n=3 AML in relapse, n=16 MDS). Median age was 70 years and most had detectable measurable residual disease at screening. There were no briquilimab infusion reactions, dose limiting toxicities, or primary graft failure events; briquilimab clearance was predictable across patients. Among the AML in CR cohort, 1-year EFS was 69.2% (95% CI, 37.3, 87.2); 1-year OS was 75% (95% CI, 40.8, 91.2). Among the MDS cohort, 1-year EFS was 53.8% (26.8, 74.8); 1-year OS was 76.4% (42.7, 91.8). One of 3 AML patients in relapse experienced a transient response. Marrow samples obtained before and after briquilimab and prior to flu/TBI demonstrated AML/MDS HSPC depletion (mean 62.4±22.7%) with resultant 3-fold increase in serum SCF. In summary, we demonstrate the feasibility, safety, and proof of concept of CD117 targeting with briquilimab as HCT conditioning for AML/MDS. The trial is registered at clinicaltrials.gov; using identifier: NCT04429191.

Secondary myelofibrosis (SMF) represents a late stage of polycythemia vera and essential thrombocythemia, with overall survival (OS) currently defined by the MYelofibrosis SECondary to PV and ET (MYSEC) Prognostic Model (MYSEC-PM). To identify additional myeloid neoplasm-associated cancer gene variants (CGVs) associated with SMF outcome, we evaluated next-generation sequencing panel testing in 644 patients within the MYSEC cohort. Overall, 429 (66.6%) subjects reported at least one CGV, with ASXL1, TET2 and DNMT3A being the most frequently involved. Specific molecular profiles affected OS (p < .001): U2AF1, TP53 or SRSF2 variants (UTS, 9.3% of cases, median OS 4.1 years) and ASXL1 without UTS (25.3%, median OS 8.4 years). By integrating these genetic signatures within the MYSEC-PM through penalized Cox regressions, we identified the following independent predictors (p from < .0001 to .02) and weighted: hemoglobin <11 g/dl (1 point), circulating blasts ⩾3% (2), platelets <150 × 109/l (2), age (0.21 points/year), ASXL1 without UTS mutations (1) and any UTS mutations (3). Finally, we developed the MYSEC-molecular prognostic model (MYSEC-mPM) allocating 582 SMF patients into four categories with different OS (p < .001): low (median OS 18.0 years, 95%CI: 14.2-not reached; score <14), intermediate-1 (8.8. years, 95%CI: 7.7-9.7; score 14-16), intermediate-2 (4.6 years, 95%CI: 3.1-7.2; score 17-18), and high risk (1.9 years, 95%CI: 1.2-2.5; score ⩾19). Additionally, in 381 SMF with available cytogenetics, the MYSEC-mPM was implemented with complex/monosomal karyotype, generating the karyotype-enhanced MYSEC-kmPM. Our study shows that genomic and cytogenetic profiling improve survival prediction in SMF, outperforming the MYSEC-PM.

Protein disulfide isomerase (PDI) functions in thrombus formation in vivo and represents a viable target for antithrombotic therapy. PDI is a redox sensor that can either reduce or oxidize substrates depending on the redox environment. Yet whether PDI functions primarily as a reductase or an oxidase in the context of thrombus formation is unknown. We have used pharmacological approaches and PDI mutants to determine how the redox state of PDI affects thrombus formation. LOC14, which inhibits PDI reductase activity and induces PDI oxidation, promoted thrombus formation in arteries exposed to FeCl3 and enhanced injury-induced platelet accumulation and fibrin formation in cremaster arterioles. Substitution of a single sulfur atom with oxygen in LOC14 reversed these prothrombotic effects. Blocking antibodies targeting PDI also reversed the effect of LOC14. Evaluation of sulfenylation-mediated PDI oxidation using C53A, C56A, R120D and T101A PDI mutants showed that the sulfenylation mechanism of PDI resembles that of H2O2 reduction by peroxiredoxins. These studies identified PDI mutants that failed to undergo H2O2-mediated oxidation, but showed normal reductase activity. When tested in vivo, either wild-type PDI or the R120D mutant fully restored normal thrombus formation following morphilino-induced knockdown of PDI. In contrast, the R120D mutant PDI was unable to fully restore thrombus formation in the setting of oxidative stress induced in mice with genetic deletion of glutathione peroxidase 3 null (GPx3-/-). These studies show that PDI-catalyzed oxidization drives thrombus formation in vivo and demonstrate a mechanism of peroxide-mediated oxidation of PDI that contributes to the prothrombotic response of oxidative stress.

Maternal alloantibodies directed to HPA-1a on fetal platelets can induce fetal-neonatal alloimmune thrombocytopenia (FNAIT) which causes intracranial hemorrhage in 10-20% of fetuses/newborns. Presentation is usually unexpected and identified by neonatal bleeding, with implications for future pregnancies. This review synthesizes advances in diagnosis, pathophysiology, and management that reshape understanding of anti-HPA-1a-mediated FNAIT. Genomic and serologic testing, together with cell-free fetal DNA for fetal HPA typing, allow accurate identification of at-risk pregnancies. Among HPA-1bb women, those who carry DRB3*01:01 are at greatest risk of forming clinically-significant anti-HPA-1a. Not only anti-HPA-1a levels but also structural features, particularly decreased Fc-fucosylation enhancing FcγR-mediated effector functions, more accurately determine disease severity. Furthermore, increased Fc-galactosylation may contribute by enhancing complement activation. Fab-mediated effects impact platelets, megakaryocytes, trophoblasts, and endothelial cells. Taken together, this explains why anti-HPA-1a levels and neonatal platelet counts alone do not reliably predict bleeding including intracranial hemorrhage. Anti-HPA-1a also induces placental inflammation increasing risks of fetal growth restriction and long-term neurodevelopmental impairment, e.g. autism. Neonatal management involves random donor and matched platelet transfusions, and also IVIG if needed. Antenatal IVIG, with/without prednisone administered in an affected pregnancy typically increases fetal platelet counts with management strategies varying internationally. Blocking FcRn has emerged as an alternative approach to both reduce maternal anti-HPAa-1a levels and inhibit its transplacental transfer. Whether antenatal treatment reduces placental inflammation requires further study. These developments support the importance of identifying predictive biomarkers of fetal risk to guide antenatal management and of preventing affected pregnancies ideally by screening all pregnancies followed by prophylaxis.

Breakthroughs in cancer immunotherapy have redefined patient care, ushering in a new era of therapeutic modalities including checkpoint inhibitors, chimeric antigen receptor (CAR) T-cells, and bispecific T-cell engagers, amongst others. However, their distinct toxicity profiles have required clinicians across all specialties to rapidly adopt an immunologic perspective in management. Among them, therapy related hemophagocytic lymphohistiocytosis (HLH)-like toxicities are increasingly recognized as part of a broader category of hyperinflammatory syndromes. The recently defined Immune effector cell-associated HLH-like syndrome (IEC-HS), characterized by hallmark clinical and biochemical features of secondary HLH, is both clinically and temporally distinct from cytokine release syndrome (CRS), typically emerging as CRS subsides or after it has resolved. In contrast, in CRS with multiorgan dysfunction (CRS-MOD), HLH-like manifestations often appear with worsening CRS and progress through standard CRS-directed therapy. Importantly, CRS-MOD is to be differentiated from the acute hyperferritinemia and transient organ toxicities seen with CRS, which often responds to standard CRS management. Clinically differentiating these HLH-like syndromes remains challenging; however, their shared pathophysiology has contributed to an evolving landscape of therapeutic strategies. Given the association of HLH-like toxicities with poor outcomes, enhanced recognition, comprehensive diagnostic approaches and early intervention strategies may improve outcomes-preserving the potential benefit of the therapies patients are receiving. In this "How I Treat," we highlight our collective approach in managing two recognized CAR-associated HLH-like toxicity syndromes, CRS-MOD and IEC-HS, and provide an overview of the current treatment landscape.

Myeloid/Lymphoid neoplasms with FGFR1 rearrangement (M/LN-FGFR1) are rare, heterogenous diseases due to fusion transcripts originated by translocations of FGFR1 with different partners, resulting in constitutive FGFR1-mediated signaling. Presentation varies from chronic myeloid neoplasms to acute leukemia or lymphoma and extramedullary localizations are common. Outside allogeneic stem cell transplantation (ASCT), survival with conventional therapy is dismal, representing an unmet clinical need. We summarize here the data that led to approval of pemigatinib, a FGFR1 inhibitor, showing unprecedented efficacy in M/LN-FGFR1.

The therapeutic landscape for systemic immunoglobulin light chain (AL) amyloidosis has been revolutionized by daratumumab-based regimens, achieving 76% five-year overall survival in the landmark ANDROMEDA trial. However, the current prognostic models were developed using patient populations treated with now-suboptimal therapies, creating a critical gap between risk stratification models and contemporary outcomes. This comprehensive review analyses prognostic factors and progression biomarkers in AL, categorizing them into disease-specific (clone-related and organ-related) and patient-specific factors. Notably, traditional baseline biomarkers including difference between involved and uninvolved free light chains (dFLC) and bone marrow plasma cell burden are losing prognostic significance with effective clone-directed therapies. Emerging approaches show promise, including dynamic markers such as minimal residual disease by free light chain mass spectrometry, cardiac imaging parameters such as global longitudinal strain, and functional measures. There is an urgent need for validation studies and prognostic model refinement to identify high-risk patients who may benefit from interventions beyond anti-plasma cell therapy.

This study assessed real-world effectiveness and safety of lisocabtagene maraleucel (liso-cel) in patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL), including those with high-risk disease, secondary central nervous system (sCNS) involvement, comorbidities, and poor fitness, using data in the Center for International Blood and Marrow Transplant Research Registry from 5 Feb 2021 to 4 Feb 2025. Eligible patients (N=1116) received liso-cel and had ≥1 effectiveness and safety assessment after infusion, including 195 in the second-line setting, 71 with sCNS, and 257 with transformed LBCL. Median age was 71.1 years (range, 21.5‒91.2), with 72.3% ≥65 years. Within the overall population, 6.6% had Eastern Cooperative Oncology Group performance status of ≥2, 53.4% had ≥1 comorbidity, and median number of prior lines of therapy was 3 (range, 1‒16). Median study follow-up was 12.6 months (95% confidence interval [CI], 12.5‒12.8). Among effectiveness-evaluable patients (n=1109), objective response rate was 81.2% and complete response rate was 71.3%. Duration of response, progression-free survival, and overall survival rates (95% CI) at 12 months were 60.2% (56.4‒63.9), 51.2% (48.0‒54.4), and 67.6% (64.5‒70.6), respectively. Cytokine release syndrome was reported in 51.0% of patients, with grade ≥3 events in 2.5%. Immune effector cell-associated neurotoxicity syndrome was reported in 26.6% of patients, with grade ≥3 events in 9.2%. The 12-month nonrelapse mortality rate was 6.1% (95% CI, 4.6‒7.8). These real-world data reinforce the effectiveness and safety of liso-cel in this broad population of patients with R/R LBCL, including younger patients and those with high-risk disease features.

The contribution of immune cells to thrombus architecture and mechanical properties in acute ischemic stroke (AIS) remains poorly understood. Using 3D imaging and multiplex staining, we mapped immune cells in human stroke thrombi and identified neutrophils as the dominant population. Analysis of 19 thrombi confirmed their positive correlation with collagen, increased stiffness, and poorer clinical outcomes. To preserve the spatial context, we developed a laser capture-based proteomic workflow and analyzed thrombus neutrophils from 34 patients with AIS stratified by 90-day outcomes, followed by validation in an independent cohort of 22 patients. Proteomic analysis revealed SERPINB3 as a neutrophil-enriched protein strongly correlated with poor prognosis. In murine models of FeCl₃-induced carotid artery thrombosis and middle cerebral artery occlusion, experiments using wild-type, neutrophil-depleted, and Serpinb3a knockout mice demonstrated that neutrophil-derived SERPINB3 promotes early thrombus formation, enhances collagen deposition, and contributes to progressive thrombus stiffening. Mechanistically, SERPINB3 secreted by neutrophils amplifies thrombus stiffness through upregulation of TGFβ1, neutrophil extracellular traps, and COL1A1. Targeted SERPINB3 knockdown delayed vascular occlusion, improved thrombolysis efficiency, and resulted in better neurological recovery. Collectively, these findings identify a neutrophil-driven mechanism underlying thrombus stiffening and establish SERPINB3 as both a prognostic biomarker and a promising therapeutic target in AIS. This project has been registered with the Chinese Clinical Trial Registration Platform (https://www.chictr.org.cn/index.html) and has successfully passed the review process (Registration Number: ChiCTR2300077911).

The TCF3::HLF fusion protein defines a highly aggressive and incurable subtype of B cell acute lymphoblastic leukemia (B-ALL). Using a newly established mouse model that faithfully recapitulates human TCF3::HLF B-ALL, including osteolytic bone lesions, we identified self-reinforcing IL-1β signaling networks as a central driver of disease progression. TCF3::HLF B-ALL cells displayed marked upregulation of inflammatory cytokines such as IL1B, IL6, and IFNG. Genetic deletion of IL1B or its receptor IL1R1 suppressed leukemic growth, reduced RANKL expression, and ameliorated bone destruction in vivo. Epigenetic profiling revealed a previously unrecognized intronic regulatory element within the IL1B locus bound directly by TCF3::HLF. Importantly, single-cell RNA-seq of patient samples demonstrated strong IL1B induction at relapse compared with diagnosis, underscoring its clinical relevance. Collectively, these findings establish the TCF3::HLF-IL-1β axis as a critical determinant of leukemic propagation and bone pathology, and highlight IL-1β blockade as a potential therapeutic strategy for this otherwise incurable leukemia.

Autologous second-generation CD7-directed CAR T-cells, expressing an anti-CD7 protein expression blocker to prevent self-killing fratricide, were infused in three pediatric/young adult patients with relapsed/refractory CD7+ acute myeloid leukemia resulting in measurable residual disease negativity. The safety profile was favorable.

CD4+CD25+Foxp3+ regulatory T cells (Tregs) are pivotal negative regulators of the adaptive immune system. Abnormalities in the number and/or function of Tregs contribute to the pathogenesis of primary immune thrombocytopenia (ITP). Strategies aimed at modulating Tregs offer potential therapeutic opportunities for ITP management. In this study, we demonstrated that inhibition of cyclin-dependent kinase 8 (CDK8) and CDK19 activity by the small-molecule inhibitor AS2863619 (AS) robustly promoted the conversion of CD4+CD25- effector T cells (Teffs) into CD4+CD25+Foxp3+ Tregs, endowing the converted Tregs with lineage stability and potent suppressive capacity. Mechanistically, AS rapidly augmented STAT5 phosphorylation and subsequent Foxp3 induction. STAT5 blockade completely abrogated this effect, confirming that the Treg-promoting activity of AS was critically dependent on STAT5 signaling. In parallel, AS suppressed STAT3 phosphorylation under IL-6-driven conditions, thereby attenuating Th17 polarization. These mechanistic findings were supported by global transcriptomic analysis, which revealed a profound transcriptional shift by broadly suppressing gene programs of Teff differentiation and function while simultaneously upregulating a robust signature characteristic of stable Tregs. Crucially, unbiased upstream analysis of these changes pinpointed STAT5, STAT3, and FOXP3 as the core transcription factors mediating the drug's effect. Functional metabolic analysis further revealed that AS mediated metabolic reprogramming in T cells by suppressing glycolysis, thereby providing the necessary metabolic adaptations for Treg conversion. In a murine model of active ITP, CDK8/CDK19 inhibition elevated Treg frequencies and ameliorated thrombocytopenia in a STAT5-dependent manner. Collectively, our study highlighted the therapeutic potential of CDK8/CDK19 inhibition in restoring immune homeostasis and managing ITP.

Chronic graft-versus-host disease (cGVHD) significantly contributes to late mortality after allogeneic stem cell transplantation, with bronchiolitis obliterans syndrome (BOS) being a particularly lethal and treatment-resistant complication despite available therapies. Bromodomain and Extra terminal (BET) proteins are epigenetic readers driving inflammatory transcriptional programs across multiple cell types. We hypothesized that BET inhibition would suppress inflammatory T and B cells while also decreasing macrophage polarization to a profibrotic phenotype, alleviating disease. In an established BOS cGVHD model, BET inhibition reduced germinal center formation and response through a reduction of the CXCL13:CXCR5 axis, inflammatory Tfh/GC B cells in the spleen along with a reduction in plasma cell infiltration within the lung. Mice with cGVHD had elevated pathogenic IgG1 and IgM, both in circulation and deposited on lung tissue, which was attenuated under BET inhibition. Single-cell RNA sequencing analysis revealed distinct cell states in the BOS lung vs. control. In cGVHD mice, GSEA analysis revealed upregulation of profibrotic Arginase1 and Tgfb1 expression in alveolar macrophages (AM) and interstitial macrophages (IM), which was significantly reduced with BET inhibition. Furthermore, BET inhibition targeted lung-infiltrating M2 macrophages, through selective depletion of CD206+FcgR+ IMs and AMs, ultimately resulting in reduced collagen deposition and improved lung function. Our findings reveal a previously unrecognized mechanistic axis of BET regulation during cGVHD fibrosis and highlight BET inhibition as a promising therapeutic strategy.

The phase 3 CRISTALLO trial (NCT04285567) compared first-line fixed-duration venetoclax-obinutuzumab (VenO) vs fludarabine, cyclophosphamide, and rituximab (FCR)/bendamustine-rituximab (BR) in patients with chronic lymphocytic leukemia, using undetectable minimal residual disease (uMRD) as the sole primary endpoint. Previously untreated patients with a cumulative illness rating scale score ≤6, creatinine clearance ≥70 mL/min, without del(17p)/TP53 mutations were randomized 1:1 to VenO or FCR/BR. The primary endpoint was uMRD (<10-4) in peripheral blood (PB) using next-generation sequencing at month 15. Key secondary endpoints included uMRD (<10-4) in PB and bone marrow (BM) at end of treatment (EOT), and progression-free survival (PFS). uMRD at deeper cutoffs were explored. At data cutoff (March 19, 2024), 80 patients received VenO and 86 received FCR/BR. Baseline characteristics were generally balanced across arms. The primary endpoint was met: 81.3% (VenO) and 54.7% (FCR/BR) achieved uMRD (<10-4) in PB at month 15 (P = .0004). uMRD (<10-4) in PB and BM at EOT was also higher with VenO vs FCR/BR. Short follow-up precluded evaluation of PFS at the first planned interim analysis; however, fewer patients progressed/died with VenO vs FCR/BR (7 vs 13). At month 15, 65.0% (VenO) and 25.6% (FCR/BR) achieved uMRD (<10-6) in PB. The overall safety profile was consistent with the known safety profile of each drug. No patient in the VenO arm was deemed high-risk for tumor lysis syndrome following obinutuzumab debulking; no clinical TLS occurred. These results confirm and extend the findings from the GAIA-CLL13 trial, validating increased depth of response with VenO vs chemoimmunotherapies.

T cell-based therapies have shown remarkable efficacy in multiple myeloma (MM), yet the disease remains largely incurable. Here, we investigated the constant domains of the immunoglobulin heavy chain (IgH) as novel targets for therapeutic T cell receptors (TCRs), after confirming high and homogeneous IGH expression in >95% of MM patients. MM cells secrete excessive monoclonal immunoglobulins (M-proteins) that drive complications but are inaccessible to CAR T-cell or antibody targeting. Peptides from IgA and IgG constant regions were eluted from HLA-A*02:01, and reactive TCRs were isolated from healthy donors using allo-HLA-A*02:01 presentation to circumvent self-tolerance. T cells engineered with two TCRs specific for IgA or IgG passed a stringent multi-tier safety screen and selectively eliminated MM cells from 20 HLA-A*02:01+ patients secreting the relevant IgH in vitro. In vivo, IgA-TCR T cells eradicated IgA+HLA-A*02:01+ MM cells in xenograft models and reduced circulating IgA in humanized mice. These findings establish immunoglobulin constant domains as viable TCR targets in MM, potentially making ~40% of patients of European descent eligible for TCR T cell therapy, and extension to additional HLA alleles could further broaden eligibility. The approach may also be applicable to lymphoma and antibody-mediated autoimmune diseases.

VEXAS syndrome is a severe adult-onset autoinflammatory disease caused by somatic mutations in the UBA1 gene, disrupting cytoplasmic ubiquitin-activating enzyme E1 function in hematopoietic progenitors. Its pathogenesis remains poorly understood, particularly the mechanisms by which UBA1 mutations disrupt myeloid cell function in the context of inflammatory stimuli. Here, we combine a genetically engineered THP-1 monocytic model with ex vivo analyses of blood and tissue samples from VEXAS patients to investigate the consequences of the canonical UBA1M41V mutation. We show that UBA1-mutated monocytes exhibit TNF-α-induced cell death, characterized by RIPK1 phosphorylation, and MLKL- and caspase-8-mediated cell death. Importantly, we extend these findings to patient-derived CD14⁺ sorted cells, confirming that these cells undergo aberrant apoptotic and necroptotic cell death. Mechanistically, activation of these cell death pathways appears to be promoted by defective NF-κB-dependent transcriptional responses and reduced cFLIP(L) expression following TNF-α stimulation. UBA1-mutated monocytes also display blunted cytokine responses to Toll-like receptor (TLR) agonists despite preserved TLR expression, linked to an impaired NF-κB response. UBA1M41V-derived macrophages exhibit a pro-inflammatory transcriptional profile with increased chemokine secretion that promotes monocyte recruitment. In addition, these UBA1-mutated macrophages display impaired efferocytosis due to lysosomal dysfunction. Together, these findings reveal a pathogenic axis in VEXAS syndrome linking UBA1 loss of function and defective ubiquitination to RIPK1-mediated inflammatory cell death, impaired antimicrobial signaling, and defective resolution mechanisms. Our study provides novel mechanistic insights into the myeloid dysfunction underlying inflammation and cytopenia in VEXAS and supports the therapeutic targeting of inflammatory cell death pathways.