JAK2-mutant Clonal Hematopoiesis is Associated with Venous Thromboembolism.

Venous thromboembolism (VTE) is common among older individuals, but provoking factors are not identified in many cases. Patients with myeloid malignancies, especially myeloproliferative neoplasms, are at increased risk for venous thrombosis. Clonal hematopoiesis of indeterminate potential (CHIP), a precursor state to myeloid malignancies, is common among the elderly and may similarly predispose to venous thrombosis. We evaluated overall and genotype-specific associations between CHIP and prevalent and incident VTE in >400,000 samples from the UK Biobank. CHIP was modestly associated with incident VTE with a hazard ratio of 1.17 (95% confidence interval (CI) 1.09-1.3; p= 0.002) but was not significantly associated with prevalent VTE with an odds ratio of 1.02 (95% CI 0.81-1.23; p= 0.81). TET2-mutant CHIP was associated with incident VTE with a hazard ratio of 1.33 (95% CI 1.05-1.69; p= 0.02). JAK2 mutations were highly associated with both prevalent and incident VTE risk with odds ratio of 6.58 (95% CI 2.65-16.29; p= 4.7 x 10-5) and hazard ratio of 4.2 (95% CI 2.18-8.08; p= 1.7 x 10-5), respectively, consistent with the thrombophilia associated with JAK2-mutant myeloproliferative neoplasms. The association between JAK2-mutant CHIP and VTE remained significant after excluding potential undiagnosed myeloproliferative neoplasms based on laboratory parameters. Compared to heterozygous factor V Leiden and heterozygous prothrombin gene mutation, JAK2-mutant CHIP was more strongly associated with VTE but was less common. These results indicate that most individuals with CHIP do not have an altered risk of thrombosis, but that individuals with JAK2-mutant CHIP have a significantly elevated risk of VTE.

Systematic identification of minor histocompatibility antigens predicts outcomes of allogeneic hematopoietic cell transplantation.

T cell alloreactivity against minor histocompatibility antigens (mHAgs)-polymorphic peptides resulting from donor-recipient (D-R) disparity at sites of genetic polymorphisms-is at the core of the therapeutic effect of allogeneic hematopoietic cell transplantation (allo-HCT). Despite the crucial role of mHAgs in graft-versus-leukemia (GvL) and graft-versus-host disease (GvHD) reactions, it remains challenging to consistently link patient-specific mHAg repertoires to clinical outcomes. Here we devise an analytic framework to systematically identify mHAgs, including their detection on HLA class I ligandomes and functional verification of their immunogenicity. The method relies on the integration of polymorphism detection by whole-exome sequencing of germline DNA from D-R pairs with organ-specific transcriptional- and proteome-level expression. Application of this pipeline to 220 HLA-matched allo-HCT D-R pairs demonstrated that total and organ-specific mHAg load could independently predict the occurrence of acute GvHD and chronic pulmonary GvHD, respectively, and defined promising GvL targets, confirmed in a validation cohort of 58 D-R pairs, for the prevention or treatment of post-transplant disease recurrence.

COVID-19 mRNA Vaccination Responses in Individuals With Sickle Cell Disease: ASH RC Sickle Cell Research Network Study.

Children and adults with sickle cell disease (SCD) have increases in morbidity and mortality with COVID-19 infections. The ASH Research Collaborative Sickle Cell Disease Research Network performed a prospective COVID-19 vaccine study to assess antibody responses and analyze whether mRNA vaccination precipitated any adverse effects unique to individuals with SCD. Forty-one participants received two doses of the Pfizer-BioNTech vaccine and provided baseline blood samples prior to vaccination and 2 months after the initial vaccination for analysis of IgG reactivity against the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Six month IgG reactivity against the viral RBD was also available in 37 patients. Post-vaccination reactogenicity was common and similar to the general population. There were no fevers that required inpatient admission. Vaso-occlusive pain within 2-3 days of 1st or 2nd vaccination was reported by 5 (12%) participants including 4 (10%) who sought medical care. Twenty-seven participants (66%) were seropositive at baseline, and all 14 (34%) initially seronegative participants converted to seropositive post vaccination. Overall, mRNA vaccination had a good risk benefit-profile in individuals with sickle cell disease.This mRNA vaccine study also marks the first evaluation of vaccine safety and antibody response in very young children with sickle cell disease. NCT05139992.

Intensive Induction Chemotherapy versus Hypomethylating Agents in Combination with Venetoclax in NPM1-mutant AML.

While intensive induction chemotherapy (IC) remains the standard of care for younger patients with acute myeloid leukemia (AML), data from older patients shows that hypomethylating agents + venetoclax (HMA/VEN) can lead to durable remissions among patients with NPM1 mutations. Whether IC or HMA/VEN is superior in patients ≥60 years-old with NPM1-mutant AML is unknown. To compare IC and HMA/VEN, we performed an international, multicenter retrospective cohort study of patients with newly diagnosed, NPM1-mutant AML.We included 221 patients (147 IC, 74 HMA/VEN) with previously untreated NPM1-mutant AML. Composite complete remission (cCR; defined as CR + CR with incomplete count recovery [CRi]) rate was similar for IC and HMA/VEN (cCR: 85% vs. 74%; p=0.067). While OS was favorable with IC in unselected patients compared to HMA/VEN (24-month OS 59% [95% CI: 52-69%] vs. 38% [95% CI 27-55%]; p=0.013), it was not statistically different among patients 60-75 years-old (60% [95% CI 52-70%] vs. 44% [95% CI 29-66%]; p=0.069) and patients who received an allogeneic stem cell transplant (70% [95% CI: 58-85%] vs. 66% [95% CI: 44-100%]; p=0.56). Subgroup analyses suggested that patients with normal cytogenetics (24-month OS with IC 65% [95% 56-74%] vs. 40% [95% CI: 26-60%] with HMA/VEN; p=0.009) and without FLT3-ITD mutations might benefit from IC compared with HMA/VEN (24-month OS: 68% [95% CI: 59-79%] vs. 43% [95% CI: 29-63%]; p=0.008). In multivariable analysis, OS was not statistically different for patients treated with IC and HMA/VEN (hazard ratio for death HMA/VEN vs. IC: 0.71; 95% CI: 0.40-1.27; p=0.25).

Targetable leukaemia dependency on noncanonical PI3Kγ signalling.

Phosphoinositide-3-kinase-γ (PI3Kγ) is implicated as a target to repolarize tumour-associated macrophages and promote antitumour immune responses in solid cancers1-4. However, cancer cell-intrinsic roles of PI3Kγ are unclear. Here, by integrating unbiased genome-wide CRISPR interference screening with functional analyses across acute leukaemias, we define a selective dependency on the PI3Kγ complex in a high-risk subset that includes myeloid, lymphoid and dendritic lineages. This dependency is characterized by innate inflammatory signalling and activation of phosphoinositide 3-kinase regulatory subunit 5 (PIK3R5), which encodes a regulatory subunit of PI3Kγ5 and stabilizes the active enzymatic complex. We identify p21 (RAC1)-activated kinase 1 (PAK1) as a noncanonical substrate of PI3Kγ that mediates this cell-intrinsic dependency and find that dephosphorylation of PAK1 by PI3Kγ inhibition impairs mitochondrial oxidative phosphorylation. Treatment with the selective PI3Kγ inhibitor eganelisib is effective in leukaemias with activated PIK3R5. In addition, the combination of eganelisib and cytarabine prolongs survival over either agent alone, even in patient-derived leukaemia xenografts with low baseline PIK3R5 expression, as residual leukaemia cells after cytarabine treatment have elevated G protein-coupled purinergic receptor activity and PAK1 phosphorylation. Together, our study reveals a targetable dependency on PI3Kγ-PAK1 signalling that is amenable to near-term evaluation in patients with acute leukaemia.

The Adverse Event Landscape of Stem Cell Transplant: Evidence for aGVHD Driving Early Transplant Associated Toxicities.

Although unrelated-donor (URD) hematopoietic cell transplantation (HCT) is associated with many toxicities, a detailed analysis of adverse events, as defined by the Common Terminology Criteria for Adverse Events (CTCAE), has not previously been curated. This represents a major unmet need, especially as it relates to assessing the safety of novel agents. We analyzed a detailed AE database from the "ABA2" randomized, double-blind, placebo-controlled clinical trial of abatacept for acute graft-versus-host disease (aGVHD) prevention, for which the FDA mandated a detailed AE assessment through Day +180, and weekly neutrophil and platelet counts through Day +100. These were analyzed for their relationship to key transplant outcomes, with a major focus on the impact of aGVHD on the development/severity of AEs. A total of 2102 AEs and 1816 neutrophil/platelet counts were analyzed from 142 8/8-HLA-matched URD HCT recipients on ABA2 (placebo cohort, n = 69, abatacept cohort, n = 73). This analysis resulted in 2 major observations. (1) Among graft source, conditioning intensity, age, and Grade 2 to 4 aGVHD, only aGVHD impacted Grade 3 to 5 AE acquisition after the first month post-transplant. (2) The development of Grade 3 to 4 aGVHD was associated with thrombocytopenia. We have created a detailed resource for the transplant community by which to contextualize clinical toxicities after transplant. It has identified aGVHD as a major driver of post-HCT Grade 3 to 5 AEs, and underscored a link between aGVHD and thrombocytopenia. This establishes a critical safety framework upon which the impact of novel post-transplant aGVHD therapeutics should be evaluated. This trial was registered at www.clinicaltrials.gov (#NCT01743131).

Organ involvement in adults with BPDCN is associated with sun exposure history, TET2 and RAS mutations, and survival.

ABSTRACT: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) can involve skin, bone marrow (BM), central nervous system (CNS), and non-CNS extramedullary sites. Preclinical models demonstrated clonal advantage of TET2-mutated plasmacytoid dendritic cells exposed to UV radiation. However, whether sun exposure, disease characteristics, and patient survival are clinically related is unclear. We classified organ involvement in 66 patients at diagnosis as skin only (n = 19), systemic plus skin (n = 33), or systemic only (n = 14). BM involvement was absent, microscopic (<5%), or overt (≥5%). UV exposure was based on clinical and demographic data. Patients with skin only BPDCN were more frequently aged ≥75 years (47% vs 19%; P = .032) and had lower rates of complex karyotype (0 vs 32%, P = .022) and mutated NRAS (0 vs 29%, P = .044). Conversely, those without skin involvement had lower UV exposure (23% vs 59%, P = .03) and fewer TET2 mutations (33% vs 72%, P = .051). The median overall survival (OS) was 23.5, 20.4, and 17.5 months for skin only, systemic plus skin, and systemic only, respectively. Patients with no BM involvement had better OS vs overt involvement (median OS, 27.3 vs 15.0 months; P = .033) and comparable with microscopic involvement (27.3 vs 23.5 months; P = .6). Overt BM involvement remained significant for OS when adjusted for baseline characteristics and treatment received. In summary, BPDCN clinical characteristics are associated with disease genetics and survival, which together may impact prognosis and indicate informative disease subtypes for future research.

Molecular ontogeny underlies the benefit of adding venetoclax to hypomethylating agents in newly diagnosed AML patients.

The clinical impact of molecular ontogeny in acute myeloid leukemia (AML) was defined in patients treated with intensive chemotherapy. In a cohort of 314 newly diagnosed AML patients, we evaluated whether molecular ontogeny subgroups have differential benefit of venetoclax (VEN) added to hypomethylating agents (HMA). In secondary ontogeny (n = 115), median overall survival (OS)(14.1 vs. 6.9 months, P = 0.0054), composite complete remission (cCR 61% vs. 18%, P < 0.001) and allogeneic hematopoietic stem cell transplant (alloHCT) (24% vs. 6%, P = 0.02) rates were better in patients treated with HMA + VEN vs. HMA. In contrast, in TP53 AML(n = 111) median OS (5.7 vs. 6.1, P = 0.93), cCR (33% vs. 37%, P = 0.82) and alloHCT rates (15% vs. 8%, P = 0.38) did not differ between HMA + VEN vs. HMA. The benefit of VEN addition in the secondary group was preserved after adjustment for significant clinicopathologic variables (HR 0.59 [95% CI 0.38-0.94], P = 0.025). The OS benefit of HMA + VEN in secondary ontogeny was similar in those with vs. without splicing mutations (P = 0.92). Secondary ontogeny AML highlights a group of patients whose disease is selectively responsive to VEN added to HMA and that the addition of VEN has no clinical benefit in TP53-mutated AML.

Fine tuning of CpG spatial distribution with DNA origami for improved cancer vaccination.

Multivalent presentation of ligands often enhances receptor activation and downstream signalling. DNA origami offers a precise nanoscale spacing of ligands, a potentially useful feature for therapeutic nanoparticles. Here we use a square-block DNA origami platform to explore the importance of the spacing of CpG oligonucleotides. CpG engages Toll-like receptors and therefore acts to activate dendritic cells. Through in vitro cell culture studies and in vivo tumour treatment models, we demonstrate that square blocks induce Th1 immune polarization when CpG is spaced at 3.5 nm. We observe that this DNA origami vaccine enhances DC activation, antigen cross-presentation, CD8 T-cell activation, Th1-polarized CD4 activation and natural-killer-cell activation. The vaccine also effectively synergizes with anti-PD-L1 for improved cancer immunotherapy in melanoma and lymphoma models and induces long-term T-cell memory. Our results suggest that DNA origami may serve as a platform for controlling adjuvant spacing and co-delivering antigens in vaccines.

Hypomethylating agents plus venetoclax compared with intensive induction chemotherapy regimens in molecularly defined secondary AML.

Molecularly defined secondary acute myeloid leukemia is associated with a prior myeloid neoplasm and confers a worse prognosis. We compared outcomes of molecularly defined secondary AML patients (n = 395) treated with daunorubicin and cytarabine (7 + 3, n = 167), liposomal daunorubicin and cytarabine (CPX-351, n = 66) or hypomethylating agents (HMA) + venetoclax (VEN) (n = 162). Median overall survival (OS) was comparable between treatment groups among patients aged >60 years. In a multivariable model HMA + VEN vs. 7 + 3 was associated with better OS (hazard ratio [HR] 0.64 [95% confidence interval (CI) 0.42-0.98, p = 0.041]), whereas CPX-351 vs. 7 + 3 was not (HR 0.79 [CI 95% 0.50-1.25, p = 0.31]). Allogeneic hematopoietic stem cell transplantation, BCOR and IDH mutations were associated with improved OS; older age, prior myeloid disease, NRAS/KRAS mutations, EZH2 mutation, and monosomal karyotype were associated with worse OS. When analyzed in each treatment separately, the IDH co-mutations benefit was seen with 7 + 3 and the detrimental effect of NRAS/KRAS co-mutations with HMA + VEN and CPX-351. In pairwise comparisons adjusted for age, HMA + VEN was associated with improved OS vs. 7 + 3 in patients with SF3B1 mutation and improved OS vs. CPX-351 in those with RNA splicing factor mutations. In molecularly defined secondary AML treatment with HMA + VEN might be preferred but could further be guided by co-mutations.

Overlap chronic GVHD is associated with adverse survival outcomes compared to classic chronic GVHD.

Chronic graft-versus-host-disease (cGVHD) is divided into two subtypes: classic (absence of acute GVHD features) and overlap cGVHD ('ocGVHD'), in which both chronic and acute GVHD clinical features are present simultaneously. While worse outcomes with ocGVHD have been reported, there are few recent analyses. We performed a secondary analysis of data from the ABA2 trial (N = 185), in which detailed GVHD data were collected prospectively and systematically adjudicated. Analyses included cumulative incidence of classic versus ocGVHD, their specific organ manifestations, global disease severity scores, non-relapse mortality (NRM), disease-free survival (DFS) and overall survival (OS) in these two cGVHD subtypes. Of 92 patients who developed cGVHD, 35 were classified as ocGVHD. The 1-year cumulative incidence, organ involvement, and global severity of classic and ocGVHD were similar between ABA2 patients receiving CNI/MTX+placebo and CNI/MTX+abatacept; thus, cohorts were combined for ocGVHD evaluation. This analysis identified ocGVHD as having significantly higher severity at presentation and at maximum global severity compared to classic cGVHD. OS and DFS were significantly lower for ocGVHD versus classic cGVHD. OcGVHD is associated with increased cGVHD severity scores, and is associated with decreased OS and DFS compared to classic cGVHD, underscoring the high risks with this cGVHD subtype.

Effect of atorvastatin versus placebo on efficacy in patients with diffuse large B-cell lymphoma receiving R-CHOP.

STOP-CA was a multicenter, double-blind, randomized, placebo-controlled trial comparing atorvastatin to placebo in treatment-naïve lymphoma patients receiving anthracycline-based chemotherapy. We performed a preplanned subgroup to analyze the impact of atorvastatin on efficacy in patients with diffuse large B-cell lymphoma (DLBCL). Patients received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) at standard doses for six 21-day cycles and were randomly assigned to receive atorvastatin 40 mg daily (n = 55) or placebo (n = 47) for 12 months. The complete response (CR) rate was numerically higher in the atorvastatin arm (95% [52/55] vs. 85% [40/47], p = .18), but this was not statistically significant. Adverse event rates were similar between the atorvastatin and placebo arms. In summary, atorvastatin did not result in a statistically significant improvement in the CR rate or progression-free survival, but both were numerically improved in the atorvastatin arm. These data warrant further investigation into the potential therapeutic role of atorvastatin added to anthracycline-based chemotherapies.

Coordinated Immune Cell Networks in the Bone Marrow Microenvironment Define the Graft versus Leukemia Response with Adoptive Cellular Therapy.

Understanding how intra-tumoral immune populations coordinate to generate anti-tumor responses following therapy can guide precise treatment prioritization. We performed systematic dissection of an established adoptive cellular therapy, donor lymphocyte infusion (DLI), by analyzing 348,905 single-cell transcriptomes from 74 longitudinal bone-marrow samples of 25 patients with relapsed myeloid leukemia; a subset was evaluated by protein-based spatial analysis. In acute myelogenous leukemia (AML) responders, diverse immune cell types within the bone-marrow microenvironment (BME) were predicted to interact with a clonally expanded population of ZNF683 + GZMB + CD8+ cytotoxic T lymphocytes (CTLs) which demonstrated in vitro specificity for autologous leukemia. This population, originating predominantly from the DLI product, expanded concurrently with NK and B cells. AML nonresponder BME revealed a paucity of crosstalk and elevated TIGIT expression in CD8+ CTLs. Our study highlights recipient BME differences as a key determinant of effective anti-leukemia response and opens new opportunities to modulate cell-based leukemia-directed therapy.

Integrative genotyping of cancer and immune phenotypes by long-read sequencing.

Single-cell transcriptomics has become the definitive method for classifying cell types and states, and can be augmented with genotype information to improve cell lineage identification. Due to constraints of short-read sequencing, current methods to detect natural genetic barcodes often require cumbersome primer panels and early commitment to targets. Here we devise a flexible long-read sequencing workflow and analysis pipeline, termed nanoranger, that starts from intermediate single-cell cDNA libraries to detect cell lineage-defining features, including single-nucleotide variants, fusion genes, isoforms, sequences of chimeric antigen and TCRs. Through systematic analysis of these classes of natural 'barcodes', we define the optimal targets for nanoranger, namely those loci close to the 5' end of highly expressed genes with transcript lengths shorter than 4 kB. As proof-of-concept, we apply nanoranger to longitudinal tracking of subclones of acute myeloid leukemia (AML) and describe the heterogeneous isoform landscape of thousands of marrow-infiltrating immune cells. We propose that enhanced cellular genotyping using nanoranger can improve the tracking of single-cell tumor and immune cell co-evolution.

A stapled lipopeptide platform for preventing and treating highly pathogenic viruses of pandemic potential.

The continued emergence of highly pathogenic viruses, which either thwart immune- and small molecule-based therapies or lack interventions entirely, mandates alternative approaches, particularly for prompt and facile pre- and post-exposure prophylaxis. Many highly pathogenic viruses, including coronaviruses, employ the six-helix bundle heptad repeat membrane fusion mechanism to achieve infection. Although heptad-repeat-2 decoys can inhibit viral entry by blocking six-helix bundle assembly, the biophysical and pharmacologic liabilities of peptides have hindered their clinical development. Here, we develop a chemically stapled lipopeptide inhibitor of SARS-CoV-2 as proof-of-concept for the platform. We show that our lead compound blocks infection by a spectrum of SARS-CoV-2 variants, exhibits mucosal persistence upon nasal administration, demonstrates enhanced stability compared to prior analogs, and mitigates infection in hamsters. We further demonstrate that our stapled lipopeptide platform yields nanomolar inhibitors of respiratory syncytial, Ebola, and Nipah viruses by targeting heptad-repeat-1 domains, which exhibit strikingly low mutation rates, enabling on-demand therapeutic intervention to combat viral outbreaks.

Phase 1b trial of tagraxofusp in combination with azacitidine with or without venetoclax in acute myeloid leukemia.

ABSTRACT: CD123, a subunit of the interleukin-3 receptor, is expressed on ∼80% of acute myeloid leukemias (AMLs). Tagraxofusp (TAG), recombinant interleukin-3 fused to a truncated diphtheria toxin payload, is a first-in-class drug targeting CD123 approved for treatment of blastic plasmacytoid dendritic cell neoplasm. We previously found that AMLs with acquired resistance to TAG were re-sensitized by the DNA hypomethylating agent azacitidine (AZA) and that TAG-exposed cells became more dependent on the antiapoptotic molecule BCL-2. Here, we report a phase 1b study in 56 adults with CD123-positive AML or high-risk myelodysplastic syndrome (MDS), first combining TAG with AZA in AML/MDS, and subsequently TAG, AZA, and the BCL-2 inhibitor venetoclax (VEN) in AML. Adverse events with 3-day TAG dosing were as expected, without indication of increased toxicity of TAG or AZA+/-VEN in combination. The recommended phase 2 dose of TAG was 12 µg/kg/day for 3 days, with 7-day AZA +/- 21-day VEN. In an expansion cohort of 26 patients (median age 71) with previously untreated European LeukemiaNet adverse-risk AML (50% TP53 mutated), triplet TAG-AZA-VEN induced response in 69% (n=18/26; 39% complete remission [CR], 19% complete remission with incomplete count recovery [CRi], 12% morphologic leukemia-free state [MLFS]). Among 13 patients with TP53 mutations, 7/13 (54%) achieved CR/CRi/MLFS (CR = 4, CRi = 2, MLFS = 1). Twelve of 17 (71%) tested responders had no flow measurable residual disease. Median overall survival and progression-free survival were 14 months (95% CI, 9.5-NA) and 8.5 months (95% CI, 5.1-NA), respectively. In summary, TAG-AZA-VEN shows encouraging safety and activity in high-risk AML, including TP53-mutated disease, supporting further clinical development of TAG combinations. The study was registered on ClinicalTrials.gov as #NCT03113643.

Influence of thrombocytopenia on bleeding and vascular events in atrial fibrillation.

Whether thrombocytopenia substantively increases the risk of hemorrhage associated with anticoagulation in patients with atrial fibrillation (AF) is not established. The purpose of this study was to compare rates of bleeding in patients with AF and thrombocytopenia (platelet count < 100 000/µL) to patients with AF and normal platelet counts (>150 000/µL). We performed a propensity score-matched, retrospective cohort study of adults (n = 1070) with a new diagnosis of AF who received a prescription for an oral anticoagulant between 2015 and 2020. The thrombocytopenia cohort was defined as having at least 2 platelet counts <100 000/µL on separate days in the period spanning the 12 weeks preceding the initiation of anticoagulation to 6 weeks after the initiation of anticoagulation. The primary end point was the 1-year cumulative incidence of major bleeding; secondary end points included clinically relevant bleeding, arterial and venous thrombotic events, and all-cause mortality. Patients with AF and thrombocytopenia experienced a higher 1-year cumulative incidence of major bleeding (13.3% vs 5.7%; P < .0001) and clinically relevant bleeding (24.5% vs 16.7%; P = .005) than the controls. Thrombocytopenia was identified as an independent risk factor for major bleeding (hazard ratio, 2.20; confidence interval, 1.36-3.58; P = .001), with increasing risk based on the severity of thrombocytopenia. The cumulative incidence of arterial thrombosis at 1 year was 3.6% in the group with thrombocytopenia and 1.5% in controls (Gray test, P = .08). These findings suggest that baseline platelet counts are an important biomarker for hemorrhagic outcomes in AF and that the degree of thrombocytopenia is an important factor in determining the level of risk.