Progress in the therapy of follicular lymphoma (FL), the most common indolent lymphoma subtype, has been achieved in recent years with significant improvement in median overall survival. Most patients diagnosed with FL will now die from other causes. Multiple novel immunotherapy and other targeted therapies are now approved for relapsed and refractory disease. However, early progression and transformation to aggressive lymphoma remain key issues requiring further innovation. We expect that bispecific antibodies will likely move to earlier use and in novel combinations. Future generations of these and chimeric antigen receptor T-cell therapy will be developed in an effort to minimize toxicity and improve efficacy. New technologies, such as circulating tumor DNA assays, may enable more rational selection and guidance of therapy duration or changes in treatment, as well as possibly substituting for follow-up imaging while monitoring patients. We also look forward to more extensive use of quality-of-life tools to select treatment for patients who have a favorable long-term outlook with multiple options. Finally, patients and clinicians now envision a day when FL is no longer referred to as "incurable." Having a definition and possibility of a "cure" and being able to optimize such a mindset in the approach of FL would represent a major advance in our future management strategy.

Thrombus structure and composition are the main determinants of the severity, course, and outcomes of thrombosis. Detailed thrombus morphology has become available due to mechanical thrombectomy, which allows for the extraction of fresh thrombi from patients, followed by scanning electron microscopy. The major structural elements of a thrombus are platelets, erythrocytes, and fibrin, each playing a critical role in the determination of biological and physical properties of thrombi, such as permeability, stiffness, and lytic and mechanical stability. The minor components include neutrophils, monocytes, von Willebrand factor, cellular microvesicles, plasma proteins, cholesterol crystals, and other structures. Platelets are responsible for the contraction (retraction) of thrombi, which results in compaction with very little free space, low permeability, and high stiffness. Because of clot contraction, erythrocytes, which are prevalent in all types of thrombi, undergo compressive deformation to polyhedral (polyhedrocytes) and polyhedral-like cells, altogether comprising pressure-deformed cells (piezocytes). Fibrin is the structural and mechanical scaffold of thrombi that changes in time and space both quantitatively and qualitatively during their formation. Fibrin is an equilibrium polymer that can adapt to forced deformations by reorientation at the microscopic level and unfolding at the molecular level. The relative volume fractions of thrombus components, along with their functional and structural forms, vary substantially, providing a basis for the diverse pathogenic mechanisms and clinical manifestations of thrombosis. Modulating any of these components leads to prospective therapeutic approaches. This review summarizes recent research describing the quantitative and qualitative morphologic characteristics of arterial and venous thrombi, which provide a basis for new therapeutic opportunities in thrombosis.

Natural killer (NK) cells are important effector cells in antibody-based immune therapies for multiple myeloma (MM) through antibody-dependent cellular cytotoxicity. Here, we used single-cell transcriptomics, flow cytometry, and functional assays to investigate the bone marrow NK-cell compartment of patients with MM at diagnosis and during treatment. We show reduced proportion of CD16+ cytotoxic NK cells in a subset of patients at diagnosis, which correlated with decreased cytokine production and NK-cell degranulation against MM cells in the presence of the anti-CD38 antibody daratumumab. In line with these findings, a low proportion of CD16+ bone marrow NK cells at diagnosis was associated with a reduced likelihood of achieving measurable (or minimal) residual disease (MRD) negativity after consolidation in patients treated with daratumumab, bortezomib, thalidomide, and dexamethasone in conjunction with autologous stem cell transplantation in the CASSIOPEIA trial. In contrast, NK-cell distribution did not predict MRD negativity in patients treated in the control arm without daratumumab. These findings highlight the impact of the bone marrow NK-cell compartment on therapeutic outcomes in patients with MM receiving immunotherapy with CD38-targeting antibodies.

Although the bone marrow is the main site of blood cell production in adults, rare pools of hematopoietic stem and progenitor cells have been found in extramedullary organs. In mice, we have previously shown that the lung contains hematopoietic progenitor cells and is a site of platelet production. Here, in the adult human lung, we show that functional hematopoietic precursors reside in the extravascular spaces with a frequency similar to the bone marrow and are capable of proliferation and engraftment in mice. The gene signature of pulmonary and medullary CD34+ hematopoietic progenitors indicates greater baseline activation of immune-, megakaryocyte/platelet-, and erythroid-related pathways in lung progenitors. Spatial transcriptomics mapped blood progenitors in the lung to an alveolar interstitium niche with only a few cells identified in an intravascular location. In human blood samples collected for stem cell transplantation, CD34+ cells with a lung signature enriched the mobilized pool of hematopoietic stem cells. These results identify the lung as a pool for uniquely programmed blood stem and progenitor cells with the potential to support hematopoiesis in humans.

Multiple myeloma (MM) is driven by clonal plasma cell (cPC)-intrinsic factors and changes in the tumor microenvironment (TME). To investigate whether residual polyclonal PCs (pPCs) are disrupted, single-cell (sc) RNA sequencing (scRNA-seq) and sc B-cell receptor analysis were applied in a cohort of 46 samples with PC dyscrasias and 21 healthy donors (HDs). Of 234 789 PCs, 64 432 were genotypically identified as pPCs with frequencies decreasing over different disease stages, from 23.66% in monoclonal gammopathy of undetermined significance to 3.23% in MMs (P = .00012). Both cPCs and pPCs had a comparable expression of typical lineage markers (ie, CD38 and CD138), whereas others were more variable (CD27 and ITGB7). Only cPCs overexpressed oncogenes (eg, CCND1/2 and NSD2), but CCND3 was often expressed in pPCs. B-cell maturation antigen was expressed on both pPCs and cPCs, whereas GPRC5D was mostly upregulated in cPCs with implications for on-target, off-tumor activity of targeted immunotherapies. In comparison with HDs, pPCs from patients showed upregulated autophagy and disrupted interaction with TME. Importantly, interferon-related pathways were significantly enriched in pPCs from patients vs HDs (adjusted P < .05) showing an inflamed phenotype affecting genotypically normal PCs. The function of pPCs was consequently affected and correlated with immunoparesis, driven by disrupted cellular interactions with TME. Leveraging our scRNA-seq data, we derived a "healthy PC signature" that could be applied to bulk transcriptomics from the CoMMpass data set and predicted significantly better progression-free survival and overall survival (log-rank P < .05 for both). Our findings show that genotypic sc identification of pPCs in PC dyscrasias has relevant pathogenic and clinical implications.

The thrombopoietin:cMPL signaling axis is a critical regulator of early hematopoiesis. However, the utility of cMPL as a standalone marker for identifying long-term repopulating hematopoietic stem cells (LT-HSCs) within the adult human CD34+ hematopoietic stem and progenitor cell (HSPC) population has not been validated. In this study, we established high cMPL surface expression as a defining feature of human LT-HSCs. Targeting the cMPL receptor facilitated the separation of human LT-HSCs from mature progenitors, a delineation not achievable with c-KIT (CD117). Leveraging this finding, we explored the therapeutic potential of cMPL as a novel target for pretransplant conditioning regimens. We developed a cMPL-targeting immunotoxin and demonstrated its ability to preferentially deplete host cMPLhigh LT-HSCs in murine xenograft models. Evaluation in rhesus macaques confirmed these findings and highlighted a favorable safety profile with rapid systemic clearance within 24 hours of administration. Proof of concept experiments validated the immunotoxin as a novel conditioning agent, enabling donor HSPC engraftment without the use of chemotherapy or irradiation. These findings advance our understanding of the molecular determinants of human hematopoiesis and underscore the potential of cMPL-targeting preparative regimens to improve therapeutic transplantation outcomes.

Rovadicitinib (TQ05105) is a novel, oral dual Janus kinase 1/2 and rho-associated coiled-coil-containing protein kinase-1/2 inhibitor targeting inflammatory and fibrotic components of chronic graft-versus-host disease (cGVHD). This phase 1b/2a, multicenter, open-label study enrolled patients with moderate or severe glucocorticoid-refractory or -dependent cGVHD to evaluate the safety and efficacy of rovadicitinib. The study followed a 3+3 design with 2 escalating doses (rovadicitinib 10 and 15 mg twice daily) and a dose expansion cohort. Primary end points included safety and recommended phase 2 dose (RP2D); the best overall response (BOR) was the key secondary end point. A total of 44 patients were enrolled (29 at 10 mg, 15 at 15 mg twice daily). Rovadicitinib was well tolerated without dose-limiting toxicity at both dosages, and no rovadicitinib-related adverse events (AEs) led to discontinuation. The most prevalent hematological AE was anemia (38.6%), with grade ≥3 of 4.6%. The RP2D was 10 mg twice daily. The BOR was 86.4% (95% confidence interval [CI], 72.6-94.8), with no difference between the 2 dosage cohorts. Besides, BOR was 72.7% in the steroid-refractory cohort and 90.9% in the steroid-dependent cohort. All affected organs exhibited responses regardless of prior therapy. The failure-free survival rate was 85.2% (95% CI, 64.5-94.3) at 12 months. Rovadicitinib reduced corticosteroid doses in 88.6% of patients and improved cGVHD symptoms in 59.1%. Rovadicitinib has favorable tolerability and notable clinical response rates, ameliorating the quality of life and reducing corticosteroid dose requirements in patients with glucocorticoid-refractory or -dependent cGVHD. This trial was registered at www.ClinicalTrials.gov as #NCT04944043.

Patients with TP53-mutated acute myeloid leukemia (AML) have an extremely poor prognosis, necessitating new treatments. The global, randomized, phase 3 ENHANCE-2 trial evaluated the anti-CD47 monoclonal antibody magrolimab plus azacitidine (Magro/Aza) for previously untreated TP53-mutated AML. Patients determined ineligible for intensive therapy were randomized to receive Magro/Aza or venetoclax plus Aza (Ven/Aza); those eligible for intensive therapy were randomized to receive Magro/Aza or 7+3 induction chemotherapy. The primary end point was overall survival (OS) in the nonintensive arm. At interim analysis, nonintensive-arm OS hazard ratio (HR) between treatment groups was 1.191 (95% confidence interval [CI], 0.744-1.906), meeting the study's definition for futility and resulting in study termination. At final analysis, median OS was 4.4 vs 6.6 months (HR, 1.132; 95% CI, 0.783-1.637; P = .5070) in the nonintensive arm (n = 205) and 7.3 vs 11.1 months (HR, 1.434; 95% CI, 0.635-3.239; P = .3798) in the intensive arm (n = 52) between Magro/Aza and control groups, respectively. Incidences of grade ≥3 adverse events were similar across Magro/Aza and control groups (nonintensive, n = 194: 96.9% and 95.9%; intensive, n = 50: 92.6% and 95.7%), including grade ≥3 anemia (nonintensive: 27.1% and 23.5%; intensive: 25.9% and 21.7%). Grade ≥3 infections were observed in 50.0% and 53.1% of patients in the nonintensive arm and 44.4% and 65.2% of intensive-arm patients. ENHANCE-2 did not meet its primary end point of OS in TP53-mutated AML but provides important data informing future studies in this challenging population. This trial was registered at www.clinicaltrials.gov as #NCT04778397.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy that is characterized by an expansion of T-cell progenitors and DNA mutations that lead to overactive NOTCH1 signaling in >50% of T-ALL cases. Using synthetic models of human T-ALL, we report that NOTCH1 dimeric signaling was crucial for the leukemogenesis of human hematopoietic stem/progenitor cells (HSPCs) from cord blood. We also identified a Notch dimerization-dependent gene signature, including the HES4 transcription factor, which induced a proliferative advantage in human HSPCs and in Notch dimerization-dependent, patient-derived xenografts of T-ALL. Interestingly, in human T-ALL cells, HES4 enforced the expression of the Δ133p53 isoform with the concomitant block of proapoptotic p53 target genes and the induction of BCL2L1 gene expression and antiapoptotic B-cell lymphoma extra-large protein. In addition, through an integrated experimental approach that included genetically modified cell lines, RNA/chromatin immunoprecipitation sequencing, and single-cell RNA sequencing profiles of primary T-ALL samples, we revealed cell subsets with Notch dimerization-dependent gene signatures, which indirectly correlated with proapoptotic genes and directly associated with cell markers of poor clinical outcome in primary T-ALL samples. Taken together, these findings highlight the crucial role of NOTCH1 dimeric signaling in human T-cell leukemogenesis and T-ALL maintenance, suggesting that a possible benefit can be obtained with a therapeutic strategy that target NOTCH1 dimer signaling or its downstream effectors.

Venetoclax (VEN) combined with hypomethylating agents is approved for frontline therapy in older/unfit patients with acute myeloid leukemia (AML). However, prospective data on this low-intensity therapy in treatment-naive younger patients with AML are lacking. This study investigated the efficacy and safety of VEN plus decitabine (VEN-DEC) as induction in untreated young fit patients with AML in a randomized trial. Patients aged 18 to 59 years eligible for intensive chemotherapy were randomized 1:1 to receive VEN-DEC or IA-12 (idarubicin and cytarabine). All patients achieved composite complete remission (CRc) underwent high-dose cytarabine consolidation. The primary end point was CRc rate after induction. Of 255 screened, 188 were enrolled and randomly assigned, with 94 in each group. In the intention-to-treat population, CRc was 89% (84/94) in the VEN-DEC group vs 79% (74/94) in the IA-12 group (noninferiority P = .0021), with measurable residual disease negativity rates of 80% (67/84) vs 76% (56/74), respectively. VEN-DEC showed superior CRc in patients aged ≥40 years (91% vs 75%) and those with adverse risk (91% vs 42%) or epigenetic mutations (91% vs 67%), but lower CRc in RUNX1::RUNX1T1 fusion cases (44% vs 88%) than IA-12. Patients in the VEN-DEC group experienced fewer grade ≥3 infections (32% vs 67%) and shorter severe thrombocytopenia duration (median, 13 vs 19 days; P < .001). At a median follow-up of 12.1 months, overall and progression-free survival were similar between groups. In conclusion, VEN-DEC demonstrated noninferior response rates with superior safety over IA-12 in young patients with AML. The trial was registered at www.clinicaltrials.gov as #NCT05177731.

Discontinuation of lenalidomide maintenance after autologous stem cell transplantation is a burning question within the multiple myeloma (MM) community, especially after the inclusion of minimal residual disease (MRD) in the disease response criteria. In this prospective study, we evaluated the conversion to MRD positivity, the treatment-free survival (TFS), and the progression-free survival (PFS) in 52 patients with MM who discontinued lenalidomide maintenance after achieving sustained bone marrow and imaging MRD negativity for 3 years. Patients who developed MRD positivity after lenalidomide discontinuation restarted lenalidomide maintenance at the same dose. The median follow-up from lenalidomide discontinuation was 3 years. Overall, 12 (23%) patients obtained MRD positivity and restarted lenalidomide maintenance. Only 4 (7.6%) patients progressed; 3 had a biochemical progression and 1 had a clinical progression. The overall median PFS was not reached, whereas the 7-year PFS from diagnosis was 90.2%. The 1-, 2-, and 3-year TFS rates were 93.9%, 91.6%, and 75.8%, respectively, whereas the 1-, 2-, and 3-year landmark PFS rates from maintenance discontinuation (study entrance) were 96.0%, 96.0%, and 92.9%, respectively. There were no statistically significant associations among age, sex, Second Revision International Staging System, type of induction therapy, and use of consolidation therapy and the effect outcomes of PFS and TFS. We conclude that maintenance discontinuation after 3 years of sustained marrow and imaging MRD negativity is associated with low rates of MRD conversion and progressive disease. Thus, in the era of modern antimyeloma treatments, a subgroup of patients may remain treatment free while in complete remission without jeopardizing disease response.

The combination of ibrutinib plus venetoclax (IV) in chronic lymphocytic leukemia (CLL) treatment leverages their complementary mechanisms of action. Studies investigating IV typically begin with a short initial course of ibrutinib, followed by venetoclax introduction for a limited duration, typically 12 months. The Swiss Group for Clinical Cancer Research (SAKK) 34/17 study is a single-arm, multicenter, phase 2 trial evaluating the effectiveness of a modified IV schedule in patients with relapsed/refractory (R/R) CLL. No prior exposure to BTK or BCL2 inhibitors was allowed. The lead-in phase with ibrutinib was extended to 6 months to reduce the tumor burden and related tumor lysis syndrome (TLS) risk. Additionally, the treatment phase with IV is prolonged to a minimum of 24 months to enhance the undetectable minimal residual disease (uMRD; 10-4) rate. The primary end point was the rate of complete response or complete response with incomplete bone marrow recovery (CR/CRi) with uMRD in both bone marrow (BM) and peripheral blood (PB). Secondary end points included assessing the proportion of patients transitioning to a low-risk category for TLS after receiving ibrutinib lead-in. Of the 30 enrolled patients with R/R CLL, 40.0% achieved uMRD CR/CRi by intention-to-treat analysis, and 53.3% showed uMRD in the BM and PB. After the lead-in period with ibrutinib, 57.1% of patients achieved a low risk of TLS. At cycle 31, the progression-free survival rate was 89.9%. These results contribute to the increasing body of evidence supporting the idea that a longer IV duration is beneficial for enhancing therapeutic effectiveness. This trial was registered at www.clinicaltrials.gov as #NCT03708003.

Fixed-duration venetoclax-rituximab (VenR) in patients with relapsed/refractory chronic lymphocytic leukemia (CLL) in the phase 3 MURANO trial resulted in superior progression-free survival (PFS) and overall survival (OS) vs bendamustine-rituximab (BR). We report the final analyses of MURANO (median follow-up, 7 years). Patients were randomized to VenR (venetoclax 400 mg daily for 2 years plus monthly rituximab for 6 months; n = 194) or BR (6 months; n = 195). In a substudy, patients with progressive disease (PD) received VenR as retreatment or crossover from BR. At the final data cut (3 August 2022), the median PFS with VenR was 54.7 months vs 17.0 months with BR. The 7-year PFS with VenR was 23.0%. The 7-year OS was 69.6% and 51.0%, respectively. Among VenR-treated patients with undetectable minimal residual disease (MRD; uMRD) and no PD at end of treatment (EOT; n = 83), the median PFS from EOT was 52.5 vs 18.0 months in patients with MRD at EOT (n = 35; P < .0001). Fourteen patients had enduring uMRD. Three distinct mutations in BCL2 in 4 patients were identified. In the substudy, 25 patients were retreated with VenR, and 9 patients crossed over to VenR; the median PFS was 23 and 27 months, and the best overall response rate was 72% and 89%, respectively. At the end of combination treatment (EOCT), after retreatment or crossover, 8 and 6 patients achieved uMRD, respectively. No new safety findings were observed. Overall, these final MURANO analyses support consideration of fixed-duration VenR therapy for patients with relapsed/refractory CLL. This trial was registered at www.clinicaltrials.gov as #NCT02005471.

The non-O blood group is a well-established risk factor for venous thromboembolism (VTE). However, the association between plasma levels of the histo-blood group ABO system transferase (BGAT), the gene product of the ABO locus, and VTE risk remains unclear. We aimed to investigate the association between plasma BGAT levels and risk of future VTE, and whether this relationship was mediated by plasma von Willebrand factor (VWF) or coagulation factor VIII (FVIII), as VWF is glycosylated by BGAT. Incident VTE-cases (n = 294) and a randomly sampled age- and-sex-weighted subcohort (n = 1066) were derived from the third survey of the Trøndelag Health Study. Baseline plasma samples (2006-2008) were subjected to the SomaScan aptamer-based-7K platform for protein measurements. Weighted Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) across BGAT quartiles. We found that ABO haplotypes (A1/A2/B/O1/O2) explained ≈80% of the BGAT plasma variability. Participants with BGAT levels in the highest quartile had 2-fold higher VTE risk (HR, 2.12; 95% CI, 1.39-3.22) compared with those with BGAT in the lowest quartile in age-, sex-, and sample batch-adjusted models. The associations were particularly pronounced for unprovoked VTE (HR, 3.71; 95% CI, 1.79-7.67) and deep vein thrombosis (HR, 3.28; 95% CI, 1.63-6.59). The HRs were similar after further adjustment for body mass index, C-reactive protein, and estimated glomerular filtration rate, and moderately attenuated when adding VWF or FVIII plasma levels to the models. Our findings indicate that elevated BGAT plasma levels are associated with increased risk of future VTE beyond what is explained by VWF and FVIII.